JP6760091B2 - Power supply and power system - Google Patents

Description

The present invention relates to a power supply device applied to a power supply system having a plurality of storage batteries, and a power supply system.

Conventionally, for example, as an in-vehicle power supply system mounted on a vehicle, two storage batteries (for example, a lead storage battery and a lithium ion storage battery) connected in parallel to an electric load are used, and each of these storage batteries is used properly for various in-vehicle electric loads. A configuration for supplying electric power is known (for example, Patent Document 1). In this case, switches are provided in the electric path between the electric load and the lead storage battery and in the electric path between the electric load and the lithium ion storage battery, and the discharge of each storage battery is controlled by opening and closing each switch. ..

Japanese Unexamined Patent Publication No. 2014-36557

By the way, when switching the storage battery of the supply source that supplies power to the electric load between the lead storage battery and the lithium ion storage battery, each switch is temporarily closed to continuously supply power. Is done. This has prevented a power defect from occurring when power from an electrical load is required. Such switching control was especially necessary in the presence of constant voltage loads that constantly demanded power.

However, when each switch is closed and all the electric paths are energized, if there is a voltage difference between the storage batteries, the current from the storage battery side with a high voltage value is not limited to the electric load. , There is a possibility that it will flow to the storage battery side where the voltage is low as it is. In this case, a problem arises depending on the allowable current amount of each switch.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power supply device and a power supply system capable of restricting the flow of current to the storage battery side when switching the storage battery. ..

In order to solve the above problems, the first invention is a power supply device applied to a power supply system in which a first storage battery and a second storage battery are connected in parallel with respect to an electric load, wherein the first storage battery and the second storage battery are connected. A first opening / closing portion provided on the first storage battery side of the connection point with the electric load in the electric path to and from the storage battery, and a second opening / closing portion provided on the second storage battery side of the connection point in the electric path. An opening / closing unit, a control unit that controls the first opening / closing unit and the second opening / closing unit, and the first opening / closing unit and the second opening / closing unit are connected in series with a first switch and a second switch, respectively. The first switch and the second switch each have a diode and a switch unit connected in parallel with the diode, and the diode of the first switch and the first switch are provided. The diodes of the two switches are provided in opposite directions to each other, and when the control unit switches the storage battery that supplies power to the electric load between the first storage battery and the second storage battery, the first Among the switch parts of the opening / closing part and the second opening / closing part, the switching part connected to the diode that regulates the current from the connection point side to the storage battery side is opened, and the same opening / closing part as the switch part is opened. The gist is to control each opening / closing unit so as to switch the storage battery during the switching intermediate state after setting the switching intermediate state in which the switch unit connected in series with the switch unit is closed. To do.

In the switching intermediate state in which the switch unit connected in parallel with the diode that regulates the flow of current from the connection point side to the storage battery side is opened, from the storage battery side to the connection point side (that is, electric load) via the diode. The flow of current is allowed, but the flow of current on the opposite side (battery side) is restricted. Therefore, even when power is supplied from both storage battery sides to the electric load when switching, it is possible to regulate the flow of current from the connection point side to one of the storage battery sides due to the voltage difference.

In the second invention, the switch portion to be opened in the switching intermediate state is the switch portion included in the opening / closing portion provided on the storage battery side having a lower voltage value among the first storage battery and the second storage battery. The gist is that.

When there is a voltage difference between each storage battery, if both the first electric path and the second electric path are energized, the current from the storage battery side with a high voltage value is not only the electric load but also the storage battery side with a low voltage value. May flow to. Therefore, by opening the switch unit connected in parallel with the diode that regulates the current to the storage battery side with a low voltage value in the intermediate switching state, it is necessary to appropriately protect the switch where an unintended overcurrent may flow. Can be done.

The third invention includes a detection unit that detects a current flowing through the first opening / closing unit and a current flowing through the second opening / closing unit, respectively, and the control unit includes the first opening / closing unit and the second opening / closing unit. Of the switch portions, all the switch portions connected to the diode that regulates the current from the connection point side to the storage battery side are in the open state, and all the switch portions other than the switch portion are in the closed state. In the switching intermediate state, based on the current detected by the detection unit, the switching unit in which a larger current is flowing is specified among the first switching unit and the second switching unit, and the specified switching unit is specified. The gist is to switch the storage battery in a state where all the switch portions of the are closed.

More current is generated in the switching intermediate state where all the switch parts connected to the diode that regulates the current from the connection point side to the storage battery side are in the open state and all the switch parts other than the switch part are in the closed state. The opening / closing part that is flowing is specified, and the specified opening / closing part is closed. Therefore, it is possible to secure time for identifying the opening / closing portion through which a larger current flows while continuing to supply electric power to the electric load. In addition, it is possible to suppress the continuous flow of a large current through the diode.

According to a fourth aspect of the present invention, when the specified opening / closing unit is an opening / closing unit that is required to be opened when switching the storage battery, the control unit includes all the switch units included in the specified opening / closing unit. The gist is to switch the storage battery by opening all the switch portions of the specified opening / closing portion without setting the closed state.

As a result, it is possible to save the trouble of opening all the switch portions of the opening / closing portion through which a larger current flows after closing them.

In the fifth invention, the electric load includes a constant voltage load that requires constant voltage power, and either the first storage battery or the second storage battery is separated from the constant voltage load. The gist is that an electrical load that temporarily requires power is connected.

When power is supplied from an electric load that temporarily requires power, the voltage on either storage battery side may temporarily drop. Even in this case, by opening the switch unit connected in parallel with the diode that regulates the flow of current to the storage battery side, and then controlling each opening / closing unit to switch the storage battery, from the connection point side. It is possible to regulate the flow of current to the storage battery side. Therefore, regardless of the power demand from the electric load, regardless of the voltage value on either storage battery side, the switch unit can be appropriately opened and closed for switching.

It is a gist of the sixth invention that a generator for supplying electric power is connected to either the first storage battery or the second storage battery.

When power is supplied from the generator, the voltage on either storage battery side may temporarily increase. Even in this case, by opening the switch unit connected in parallel with the diode that regulates the flow of current to the storage battery side, and then controlling each opening / closing unit to switch the storage battery, from the connection point side. It is possible to regulate the flow of current to the storage battery side. Therefore, regardless of the power generation status of the generator, the switch unit can be appropriately opened and closed for switching regardless of which storage battery side has a higher voltage value.

The gist of the seventh invention is that the control unit switches the storage battery when it determines that an abnormality has occurred in the power supply device.

For example, even if a power supply source other than the storage battery or an electric load is connected to each storage battery and there is a power supply or a power request from them, when switching the storage battery, from the connection point side to the storage battery side with a low voltage. No current flows. That is, the switch unit can be opened and closed without considering the power supply source other than the storage battery or the state of the electric load. Therefore, it is possible to perform appropriate switching control when an abnormality occurs that requires quick switching.

An eighth invention is an electric path between the first storage battery and the second storage battery in a power supply system including an electric load and a first storage battery and a second storage battery connected in parallel to the electric load. The first opening / closing part provided on the first storage battery side of the connection point with the electric load, the second opening / closing part provided on the second storage battery side of the connection point in the electric path, and the first opening / closing part. The opening / closing unit and the control unit that controls the second opening / closing unit are provided, and the first opening / closing unit and the second opening / closing unit are configured by connecting a first switch and a second switch in series, respectively. The first switch and the second switch each have a diode and a switch portion connected in parallel with the diode, and the diode of the first switch and the diode of the second switch are connected to each other. The control unit is provided in the opposite direction, and when the storage battery that supplies power to the electric load is switched between the first storage battery and the second storage battery, the first opening / closing unit and the second opening / closing unit are provided. Among the switch parts of the unit, the switch part connected to the diode that regulates the current from the connection point side to the storage battery side is opened, and the switch part is in the same opening / closing part as the switch part. The gist is to control each opening / closing unit so as to switch the storage battery during the switching intermediate state after the switching intermediate state in which the switch unit connected in series is closed is set.

In the switching intermediate state in which the switch unit connected in parallel with the diode that regulates the flow of current from the connection point side to the storage battery side is opened, in order to switch the storage battery, the storage battery side to the connection point side (that is, that is, via the diode) , Electric load) is allowed to flow, but the opposite side (battery side) is restricted from flowing current. Therefore, even when power is supplied from both storage battery sides to the electric load when switching, it is possible to regulate the flow of current from the connection point side to one of the storage battery sides due to the voltage difference.

An electrical circuit diagram showing a power supply system. (A) and (b) are diagrams showing the energized state in the IG-on state, and (c) is a diagram showing the energized state in the fail-safe process. A flowchart showing the switching process. The figure explaining the opening / closing order of a switch part. The figure explaining the opening / closing order of a switch part. The figure explaining the opening / closing order of a switch part. The figure explaining the opening / closing order of a switch part. The flowchart which shows the switching process of 2nd Embodiment. An electrical circuit diagram showing another example power supply system. The flowchart which shows the switching process of another example.

(First Embodiment)
Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. In the present embodiment, in a vehicle traveling with an engine (internal combustion engine) as a drive source, an in-vehicle power supply system that supplies electric power to various devices of the vehicle is embodied.

As shown in FIG. 1, this power supply system is a two power supply system having a lead storage battery 11 as a first storage battery and a lithium ion storage battery 12 as a second storage battery, and electric loads from the storage batteries 11 and 12 respectively. It is possible to supply power to 13 and the electric load 15. Further, each of the storage batteries 11 and 12 can be charged by the rotary electric machine 14. In this system, the lead storage battery 11 and the lithium ion storage battery 12 are connected in parallel to the rotary electric machine 14, and the lead storage battery 11 and the lithium ion storage battery 12 are connected in parallel to the electric load 15.

The lead storage battery 11 is a well-known general-purpose storage battery. On the other hand, the lithium ion storage battery 12 is a high-density storage battery having a smaller power loss during charging / discharging, a higher output density, and a higher energy density than the lead storage battery 11. The lithium ion storage battery 12 is preferably a storage battery having higher energy efficiency during charging / discharging than the lead storage battery 11. Further, the lithium ion storage battery 12 is configured as an assembled battery each having a plurality of cell cells. The rated voltage of each of these storage batteries 11 and 12 is the same, for example, 12V.

Although a specific description by illustration is omitted, the lithium ion storage battery 12 is housed in a storage case and is configured as a battery unit U integrated with a substrate. In this embodiment, the battery unit U constitutes a "power supply device". In FIG. 1, the battery unit U is shown surrounded by a broken line. The battery unit U has external terminals P0, P1 and P2, of which the lead-acid battery 11 and the electric load 13 are connected to the external terminal P0, the rotary electric machine 14 is connected to the external terminal P1, and the external terminal P2 is connected. The electrical load 15 is connected.

The rotary electric machine 14 is a generator with a motor function having a three-phase AC motor and an inverter as a power conversion device, and is configured as an ISG (Integrated Starter Generator) integrated with mechanical and electrical power. The rotary electric machine 14 has a power generation function of generating power (regenerative power generation) by rotating the engine output shaft and the axle, and a power running function of applying a rotational force to the engine output shaft. The rotary electric machine 14 supplies the generated electric power to the storage batteries 11 and 12 and the electric load 15.

The electric load 15 includes a constant voltage load in which the voltage of the supplied power is required to be constant or fluctuate within a predetermined range. The electric load 15 can be said to be a protected load. Further, it can be said that the electric load 15 is a load to which a power failure is not allowed.

Specific examples of the electric load 15 which is a constant voltage required load include various ECUs such as a navigation device, an audio device, a meter device, and an engine ECU. In this case, by suppressing the voltage fluctuation of the supplied power, unnecessary resets and the like are suppressed in each of the above devices, and stable operation can be realized. The electric load 15 may include a traveling system actuator such as an electric steering device or a braking device.

The electric load 13 is a general electric load other than the constant voltage required load. It can be said that the electric load 13 is a load to which a power failure is allowed as compared with the electric load 15. Specific examples of the electric load 13 include a starter, a seat heater, a heater for a defroster of a rear window, a headlight, a wiper of a front window, a blower fan of an air conditioner, and the like.

Next, the battery unit U will be described. The battery unit U is provided with an electric path L1 connecting the external terminals P0 and P1 and an electric path L2 connecting the connection point N1 on the electric path L1 and the lithium ion storage battery 12 as an electric path in the unit. .. Of these, the switch 21 is provided in the electric path L1 and the switch 22 is provided in the electric path L2. The generated power of the rotary electric machine 14 is supplied to the lead storage battery 11 and the lithium ion storage battery 12 via the electric paths L1 and L2. In terms of the electric path from the lead storage battery 11 to the lithium ion storage battery 12, a switch 21 is provided between the external terminal P0 and the connection point N1 of the rotary electric machine 14, and the lithium ion storage battery 12 is more than the connection point N1. A switch 22 is provided on the side.

Further, in the battery unit U of the present embodiment, in addition to the electric paths L1 and L2, electricity that connects the connection point N2 (the point between the external terminal P0 and the switch 21) on the electric path L1 and the external terminal P2. It has a path L3. The electric path L3 forms a path that enables power to be supplied from the lead-acid battery 11 to the electric load 15. A switch 23 is provided in the electric path L3 (specifically, between the connection point N2-connection point N4).

Further, in the battery unit U, the connection point N3 of the electric path L2 (the point between the switch 22 and the lithium ion storage battery 12) and the connection point N4 on the electric path L3 (the point between the switch 23 and the external terminal P2) , Is provided with an electric path L4 for connecting the. The electric path L4 forms a path that enables power to be supplied from the lithium ion storage battery 12 to the electric load 15. A switch 24 is provided in the electric path L4 (specifically, between the connection points N3- and the connection points N4). In terms of the electrical path from the lead-acid battery 11 to the lithium-ion battery 12, a switch 23 is provided between the external terminal P0 and the connection point N4, and the switch 24 is located closer to the lithium-ion battery 12 than the connection point N4. It is provided. The switches 21 and 23 correspond to the "first opening / closing part", and the switches 22 and 24 correspond to the "second opening / closing part".

Each of these switches 21 to 24 includes a set of two semiconductor switches 21a, 21b, 22a, 22b, 23a, 23b, 24a, 24b. The semiconductor switches 21a to 24a and 21b to 24b are MOSFETs, and the parasitic diodes of the two sets of MOSFETs are connected in series so as to be opposite to each other.

For example, the switch 23 will be described in detail. The semiconductor switches 23a and 23b are connected in series. The semiconductor switches 23a and 23b inevitably have a rectifying means due to their internal structure. That is, the internal circuit of the semiconductor switch 23a is a circuit in which the switch portion Sa3 and the parasitic diode Da3 are connected in parallel. Similarly, the semiconductor switch 23b is also a circuit in which the switch unit Sb3 and the parasitic diode Db3 are connected in parallel. Then, these semiconductor switches 23a and 23b are connected in series so that the parasitic diodes Da3 and Db3 are opposite to each other. The semiconductor switch 23a corresponds to the first switch, and the semiconductor switch 23b corresponds to the second switch.

Similarly, the switch 24 is configured by connecting semiconductor switches 24a and 24b in series. The internal circuit of the semiconductor switch 24a is a circuit in which the switch portion Sa4 and the parasitic diode Da4 are connected in parallel. Similarly, the semiconductor switch 24b is also a circuit in which the switch unit Sb4 and the parasitic diode Db4 are connected in parallel. Then, these semiconductor switches 24a and 24b are connected in series so that the parasitic diodes Da4 and Db4 are opposite to each other. The semiconductor switch 24a corresponds to the first switch, and the semiconductor switch 24b corresponds to the second switch.

Although the switches 23 and 24 have been described for convenience, the switches 21 and 22 are also configured in the same manner. Further, in FIG. 1, the parasitic diodes Da3 and Db3 are connected to each other by the anodes, but the cathodes of the parasitic diodes Da3 and Db3 may be connected to each other. The same applies to the other switches 21, 22, and 24.

By configuring the switches 21 to 24 as described above, for example, when the switch 23 is turned off, that is, when the semiconductor switches 23a and 23b are turned off, a current flows through the parasitic diodes Da3 and Db3. Is completely blocked.

As the semiconductor switches 21a to 24a and 21b to 24b, it is also possible to use an IGBT, a bipolar transistor, or the like instead of the MOSFET. When an IGBT or a bipolar transistor is used as the switch unit, a diode instead of the parasitic diode may be connected to the switch unit in parallel. Further, in the switches 21 to 24, a plurality of sets of MOSFETs may be provided to connect the plurality of sets of MOSFETs in parallel.

Further, the battery unit U is provided with bypass paths B1 and B2 that enable the lead storage battery 11 to be connected to the rotary electric machine 14 and the electric load 15 without going through the switches 21 and 23 in the unit. That is, the bypass paths B1 and B2 are provided so as to bypass the switches 21 and 23 on the electric paths L1 and L3.

One end of the bypass path B1 is connected to the connection point N2 on the electric path L1 inside the unit, and the other end is connected to the connection point N1 on the electric path L1 inside the unit. The bypass path B1 is provided with a bypass opening / closing circuit RE1 that turns the bypass path B1 into a state of energization or energization cutoff. The bypass opening / closing circuit RE1 has, for example, a normally closed mechanical relay. If the bypass path B1 is energized by the bypass opening / closing circuit RE1, the generated power is supplied from the rotary electric machine 14 to the lead-acid battery 11 via the bypass path B1 even when the switch 21 is turned off. Is possible.

One end of the bypass path B2 is connected to the connection point N2 on the electric path L1 inside the unit, and the other end is connected to the connection point N4 on the electric path L3 inside the unit. The bypass path B2 is provided with a bypass opening / closing circuit RE2 that turns the bypass path B2 into a state of energization or energization. The bypass opening / closing circuit RE2 has, for example, a normally closed mechanical relay. If the bypass path B2 is energized by the bypass switching circuit RE2, power can be supplied from the lead storage battery 11 to the electric load 15 via the bypass path B2 even when the switch 23 is turned off. It is possible.

The battery unit U is provided with a voltage detector 31 that detects the voltage value on the lead storage battery 11 side and a voltage detector 32 that detects the voltage value on the lithium ion storage battery 12 side. More specifically, the voltage detector 31 that detects the voltage value on the lead-acid battery 11 side detects the voltage value at the point (for example, the external terminal P0) on the lead-acid battery 11 side of the switch 23 in the electric path L3. Further, the voltage detector 32 that detects the voltage value on the lithium ion storage battery 12 side detects the voltage value at the point (for example, the connection point N3) on the lithium ion storage battery 12 side of the switch 24 in the electric path L4.

Further, the external terminal P0 is connected to the lead storage battery 11 via a fuse 35. Further, the external terminal P2 is connected to the electric load 15 via a fuse 38. Further, the connection point N2 is connected to the bypass switching circuit RE1 via a fuse 37.

The battery unit U includes switches 21 to 24 and a control unit 51 that controls bypass switching circuits RE1 and RE2. The control unit 51 is composed of a microcomputer including a CPU, a ROM, a RAM, an input / output interface, and the like.

The control unit 51 controls the switches 21 to 24 and the like based on the storage state and the like of the storage batteries 11 and 12. For example, the control unit 51 controls to close the bypass opening / closing circuits RE1 and RE2 and open the switches 21 to 24 in the stopped state of the vehicle-mounted power supply system (that is, the ignition switch is off). In the following, the stopped state of the in-vehicle power supply system is referred to as an IG off state. Further, the operating state of the in-vehicle power supply system (that is, the ignition switch on state) is indicated as the IG on state.

On the other hand, the control unit 51 controls the bypass opening / closing circuits RE1 and RE2 to be opened and the switches 21 to 24 to be appropriately opened / closed in the IG on state. At that time, the control unit 51 appropriately controls each of the switches 21 to 24 so that at least one of the switch 23 and the switch 24 is closed. That is, the control unit 51 appropriately controls each of the switches 21 to 24 so that the electric power continues to be supplied to the electric load 15.

Specifically, the control unit 51 calculates the SOC (residual capacity: State Of Charge) of the lithium ion storage battery 12. Then, the control unit 51 controls the switches 21 to 24 so that the SOC is maintained within a predetermined range of use, and controls the charging and discharging of the lead storage battery 11 and the lithium ion storage battery 12. That is, the control unit 51 selectively uses the lead storage battery 11 and the lithium ion storage battery 12 to charge and discharge.

In addition, the control unit 51 determines an abnormality related to the battery unit U. Examples of the abnormality related to the battery unit U include an abnormality related to charging / discharging of the lithium ion storage battery 12 and an abnormality related to the switches 21 to 24. Then, the control unit 51 forcibly opens the switches 21 to 24 and closes the bypass opening / closing circuits RE1 and RE2 as a fail-safe process at the time of abnormality determination.

For example, the control unit 51 uses a current sensor or a temperature sensor to detect that an overcurrent is flowing through the lithium ion storage battery 12 or that the temperature of the lithium ion storage battery 12 is excessively rising, and at the time of such an abnormality determination. Perform fail-safe processing. As a result, the control unit 51 also functions as an abnormality determination unit for determining an abnormality (failure) of the in-vehicle power supply system.

An ECU 52 including, for example, an engine ECU is connected to the control unit 51. The ECU 52 is composed of a microcomputer including a CPU, a ROM, a RAM, an input / output interface, and the like, and controls the operation of the engine based on the engine operating state and the vehicle running state each time. The control unit 51 and the ECU 52 are connected by a communication network such as CAN so that they can communicate with each other, and various data stored in the control unit 51 and the ECU 52 can be shared with each other. The ECU 52 may detect an abnormality (failure) in the in-vehicle power supply system, and the ECU 52 may notify the control unit 51 of the failure (abnormality). When an abnormality is notified from the ECU 52, the control unit 51 performs various processes as a fail-safe process.

Next, the state of the battery unit U in the IG on state will be described. In the IG on state, for example, as shown in FIG. 2A, the switches 21 and 23 may be closed, the switches 22 and 24 may be open, and the bypass opening / closing circuits RE1 and RE2 may be open. If the rotary electric machine 14 is generating power in such a state, the generated power is supplied to the lead storage battery 11 and the generated power is supplied to the electric load 15. Further, even if power generation is not performed, power is supplied from the lead storage battery 11 to the electric load 15.

Further, in the IG on state, for example, as shown in FIG. 2B, the switches 22 and 24 may be closed, the switches 21 and 23 may be open, and the bypass opening / closing circuits RE1 and RE2 may be open. is there. If the rotary electric machine 14 is generating power in such a state, the generated power is supplied to the lithium ion storage battery 12 and the generated power is supplied to the electric load 15. Further, even if power generation is not performed, electric power is supplied from the lithium ion storage battery 12 to the electric load 15.

In the IG on state, each switch 21 to 24 is appropriately controlled so that at least one of the switch 23 and the switch 24 is turned on (closed). Therefore, it is possible to supply electric power to the electric load 15 from at least one of the lead storage battery 11 and the lithium ion storage battery 12.

Next, the state of the battery unit U in the fail-safe state will be described. In the fail-safe state, as shown in FIG. 2C, the switches 21 to 24 are open and the bypass opening / closing circuits RE1 and RE2 are closed. If the rotary electric machine 14 is generating power in such a state, the generated power is supplied to the lead storage battery 11 and the generated power is supplied to the electric load 15. Further, even if power generation is not performed, power is supplied from the lead storage battery 11 to the electric load 15.

By the way, the electric load 15 includes a constant voltage load. Therefore, it is necessary to prevent a power defect from occurring when switching the storage batteries 11 and 12 that supply power to the electric load 15 between the lead storage battery 11 and the lithium ion storage battery 12. That is, when switching between the switch 23 and the switch 24, a power defect occurs by temporarily setting the power to be supplied from both the storage batteries 11 and 12 and then opening any of the switches 23 and 24. You need to avoid it.

However, when power is temporarily supplied from both the storage batteries 11 and 12, an unintended overcurrent may flow to the switch 23 and the switch 24 depending on the voltage difference between the storage batteries 11 and 12. That is, when both the electric paths L3 and L4 are energized, the storage batteries 11 and 12 having a high voltage value are transferred to the storage batteries 11 and 12 having a low voltage value via the switch 23 and the switch 24. An overcurrent may flow between the storage batteries 11 and 12.

Further, as shown in FIG. 1, an electric load 13 for temporarily supplying electric power is connected to the lead storage battery 11. When electric power is requested from the electric load 13, the voltage value on the lead storage battery 11 side that supplies electric power to the electric load 13 may be lower than that on the lithium ion storage battery 12 side. That is, the voltage value at the external terminal P0 to which the lead storage battery 11 is connected may be lower than the voltage value of the lithium ion storage battery 12. Similarly, in this case as well, an overcurrent may flow from the lithium ion storage battery 12 side having a high voltage value to the lead storage battery 11 side having a low voltage value via the switch 23 and the switch 24.

Further, as shown in FIG. 1, the lead storage battery 11 and the lithium ion storage battery 12 are connected to the rotary electric machine 14 via electric paths L1 and L2, respectively. When either of the electric paths L1 and L2 is energized and the generated power is supplied from the rotary electric machine 14, the voltage values on the storage batteries 11 and 12 to which the generated power is supplied are supplied. It may be higher than the voltage value on the storage batteries 11 and 12 side.

That is, when the generated power is supplied from the rotary electric machine 14 to the lead storage battery 11 via the electric path L1 (for example, the state of FIG. 2A), the voltage value at the external terminal P0 to which the lead storage battery 11 is connected is , It may be higher than the voltage value of the lithium ion storage battery 12. In this case, if both the electric paths L3 and L4 are energized, even if the electric path L2 is energized, the lead-acid battery 11 side having a high voltage value (that is, the outside) is passed through the switch 23 and the switch 24. There is a possibility that an overcurrent may flow from the terminal P0 side) to the lithium ion storage battery 12 side (that is, the connection point N3 side) having a low voltage value.

Further, when the generated power is supplied from the rotary electric machine 14 to the lithium ion storage battery 12 via the electric path L2 (for example, the state of FIG. 2B), the voltage at the connection point N3 to which the lithium ion storage battery 12 is connected. The value may be higher than the voltage value of the lead storage battery 11. In this case, if both the electric paths L3 and L4 are energized, even if the electric path L1 is in the energized state, the lithium ion storage battery 12 side having a high voltage value (that is, that is, via the switch 23 and the switch 24) (that is, There is a possibility that an overcurrent may flow from the connection point N3 side) to the lead storage battery 11 side (that is, the external terminal P0 side) having a low voltage value.

In these cases, an excessive current may flow through the switch 23 and the switch 24 with respect to the allowable current amount. At this time, there is a possibility that some abnormality may occur in the switch 23 or the switch 24.

In general, the rotary electric machine 14 adjusts the amount of power generation so that the voltage becomes constant. Therefore, when a current flows into the storage batteries 11 and 12 having a low voltage value (not subject to charging) via the switches 23 and 24, the rotary electric machine 14 can maintain the voltage and increase the amount of power generation. There is sex. In this case, a larger current may flow through the switch 23 and the switch 24.

Therefore, when the switches 23 and 24 are switched on and off, overcurrent is restricted from flowing from the connection point N4 side to the storage batteries 11 and 12 side via the switch 23 and the switch 24 by performing predetermined control. .. The details will be described below.

When the control unit 51 is requested (determined) to switch the switches 23 and 24 on and off, the control unit 51 acquires the voltage value on the lead storage battery 11 side and the voltage value on the lithium ion storage battery 12 side. Specifically, the control unit 51 is connected to the voltage detectors 31 and 32, and acquires voltage values from the voltage detectors 31 and 32, respectively.

The control unit 51 compares the voltage value on the lead storage battery 11 side with the voltage value on the lithium ion storage battery 12 side. Then, the control unit 51 identifies the switch unit on the storage battery side having a low voltage value among the switch units Sa3, Sa4, Sb3, and Sb4 of the switches 23 and 24. Then, the control unit 51 opens (opens) the switch unit connected in parallel with the parasitic diode that allows the current to the connection point N4 side and regulates the current to the opposite side among the specified switch units. State). At the same time, the control unit 51 causes the other switch unit of the specified switch units to be closed (closed state). That is, the control unit 51 closes the specified switch unit connected in parallel with the parasitic diode that regulates the current to the connection point N4 side and allows the current to the opposite side. .. This state is referred to as a switching intermediate state.

For example, when the lead-acid battery 11 side is low, the current from the storage battery side having a low voltage value to the connection point N4 side is the current from the lead-acid battery 11 side, and specifically, the external terminal P0 (or the connection point N2). It is a current from the connection point N4 (or the external terminal P2). In this case, the control unit 51 specifies the switch units Sa3 and Sb3 as the switch units on the lead-acid battery 11 side having a low voltage value. Then, the control unit 51 opens the switch unit Sb3 connected in parallel with the parasitic diode Db3 that regulates the current to the lead storage battery 11 side among the specified switch units Sa3 and Sb3, and also opens the switch unit Sa3. Make it closed.

On the other hand, when the lithium ion storage battery 12 side is low, the current from the storage battery side having a low voltage value to the connection point N4 side is the current from the lithium ion storage battery 12 side. Specifically, the connection point N3 to the connection point N4 (Or the current to the external terminal P2). In this case, the control unit 51 specifies the switch units Sa4 and Sb4 as the switch units on the lithium ion storage battery 12 side having a low voltage value. Then, the control unit 51 also opens the switch unit Sa4 connected in parallel with the parasitic diode Da4 that regulates the current to the lithium ion storage battery 12 side among the specified switch units Sa4 and Sb4, and also opens the switch unit Sb4. To be closed.

In this switching intermediate state, the control unit 51 closes all of the switch units Sa3, Sa4, Sb3, and Sb4 of the switches 23 and 24 on the storage battery side having a high voltage value. As a result, electric power is supplied to the electric load 15 from any of the storage batteries 11 and 12.

On the other hand, in the switching intermediate state, among the switch portions on the storage battery side having a low voltage value, the switch portion connected in parallel with the parasitic diode that regulates the current to the connection point N4 side is open. Therefore, even if the voltage difference between the storage batteries 11 and 12 is large, the current is restricted from flowing from the connection point N4 side to the storage battery side having a low voltage value.

After the switching intermediate state is reached, the control unit 51 identifies the switches 23 and 24 that are requested (determined) to be released by the switching request among the switches 23 and 24, and releases all the switch units of the switch. Let me. That is, the control unit 51 identifies a switch provided in the electric path in the state of power cutoff among the electric paths L3 and L4, and opens the switch unit of the switch. As a result, of the electric paths L3 and L4, the electric path between the electric paths L3 and L4 and the storage battery that does not supply electric power to the electric load 15 is cut off. As described above, the storage batteries 11 and 12 for supplying electric power to the electric load 15 are switched.

When the switch on the storage battery side having a low voltage value is a switch to be closed, the switch portion on the storage battery side having a high voltage value is opened and then the switch on the storage battery side having a low voltage value is closed. That is, the switching intermediate state is terminated.

As described above, when the switches 23 and 24 are switched on and off, a current flows from the connection point N4 side to the storage battery side having a low voltage value through the switches 23 and 24 while continuing the power supply to the electric load 15. You can regulate that. That is, it is possible to regulate the flow of current from the external terminal P0 to the connection point N3 and the flow of current from the connection point N3 to the external terminal P0 through the electric paths L3 and L4.

By the way, when the fail-safe process is performed, the control unit 51 closes the switch 23, opens the switch 24, closes the bypass opening / closing circuit RE2, and then opens the switch 23. There is. As a result, it is possible to avoid a situation in which the bypass opening / closing circuit RE2 and the switch 24 are closed at the same time. That is, when the bypass switching circuit RE2 and the switch 24 are closed at the same time, a current can flow from the connection point N4 side to any storage battery side via the bypass switching circuit RE2 and the switch 24 due to the potential difference between the storage batteries 11 and 12. There is sex. Therefore, by closing the switch 23, opening the switch 24, and then closing the bypass switching circuit RE2, it is possible to prevent current from flowing to either storage battery side.

Next, a switching process executed when the switches 23 and 24 are switched on and off with each other will be described with reference to FIG. The switching process is executed by the control unit 51 at predetermined intervals.

The control unit 51 determines whether or not a switching request has occurred (step S101). The switching request (decision to switch the switches 23 and 24) is generated based on the processing result of the control unit 51 and the command from the ECU 52. For example, the control unit 51 itself may make a switching request based on the charging status of the storage batteries 11 and 12. Further, the ECU 52 may make a switching request depending on the power generation status of the rotary electric machine 14, the power running drive, the power request from the electric load 13, and the like. In addition, a switching request may occur even in the fail-safe process. If no switching request has occurred (step S101: NO), the control unit 51 ends the switching process.

When the switching request is generated (step S101: YES), the control unit 51 compares the voltage values of the storage batteries 11 and 12 acquired from the voltage detectors 31 and 32, and compares the voltage values of the lead-acid batteries 11 side (Pb). It is determined whether or not the voltage) is higher than the voltage value (Li voltage) on the lithium ion storage battery 12 side (step S102).

When the voltage value on the lead-acid battery 11 side is higher (step S102: YES), the control unit 51 is a switching request for opening the closed switch 23 and closing the opened switch 24. (Step S103). Which switches 23 and 24 are opened or closed is specified based on the processing result of the control unit 51 and the content of the command from the ECU 52. For example, when the charge amount of one storage battery 11 or 12 becomes low, a switching request for specifying the opening / closing of the switches 23 and 24 is made so as to supply electric power from the other storage battery 11 and 12 to the electric load 15. .. Further, when an abnormality occurs, a switching request for specifying the opening / closing of the switches 23 and 24 is made so that the power is supplied from the lead storage battery 11.

When the request is for switching to open the switch 23 (step S103: YES), the control unit 51 closes the switch unit Sb4 of the switch 24 (step S104). That is, when the voltage value on the lithium ion storage battery 12 side is low, the control unit 51 opens the switch unit Sa4 and closes the switch unit Sb4 (to enter the switching intermediate state), so that the switch unit Sb4 To close.

After a predetermined time (for example, 100 ms) has elapsed from step S104, the control unit 51 releases the switch units Sa3 and Sb3 of the switch 23 that are requested (determined) to be released (step S105). Further, the control unit 51 closes the switch unit Sa4 (step S106) and ends the switching process. By closing the switch unit Sa4, the switching intermediate state is also terminated.

If it is not a changeover request for opening the switch 23 (step S103: NO), that is, if it is a changeover request for closing the open switch 23, the control unit 51 releases the switch unit Sa4 of the switch 24 (step S107). ). When the voltage value of the lead storage battery 11 is higher, that is, when the voltage value on the lithium ion storage battery 12 side is lower, the switch unit Sa4 is opened and the switch unit Sb4 is closed (in the switching intermediate state). ), The switch unit Sa4 is opened.

After a predetermined time has elapsed from step S107, the control unit 51 closes the switch units Sa3 and Sb3 of the switch 23 (step S108). That is, in step S108, the control unit 51 closes all the switch units Sa3 and Sb3 on the lead-acid battery 11 side having a high voltage value. The control unit 51 releases the switch unit Sb4 of the switch 24 that is requested (determined) to be released (step S109), and ends the switching process.

When the voltage value on the lead-acid battery 11 side is lower (step S102: NO), whether or not the control unit 51 is a switching request for opening the closed switch 23 and closing the opened switch 24. (Step S110).

When it is a changeover request to open the closed switch 23 (step S110: YES), the control unit 51 releases the switch unit Sb3 of the switch 23 (step S111). When the voltage value on the lead-acid battery 11 side is lower, the control unit 51 opens the switch unit Sb3 and closes the switch unit Sa3 (to bring it into the switching intermediate state). Let it open.

After a predetermined time has elapsed from step S111, the control unit 51 closes the switch units Sa4 and Sb4 of the switch 24 (step S112). That is, in step S112, the control unit 51 closes all the switch units Sa4 and Sb4 on the lithium ion storage battery 12 side having a high voltage value. After that, the control unit 51 releases the switch unit Sa3 of the switch 23, which is requested (determined) to be released (step S113), and ends the switching process.

If it is not a changeover request to open the closed switch 23 (step S110: NO), that is, if it is a changeover request to close the open switch 23, the control unit 51 closes the switch unit Sa3 of the switch 23. (Step S114). When the voltage value on the lead-acid battery 11 side is lower, the control unit 51 opens the switch unit Sb3 and closes the switch unit Sa3 (to put it in the switching intermediate state). Close it.

After a lapse of a predetermined time from step S114, the control unit 51 releases the switch units Sa4 and Sb4 of the switch 24 that are requested (determined) to be released (step S115). After that, the control unit 51 closes the switch unit Sb3 (step S116), and ends the switching process. By closing the switch unit Sb3, the switching intermediate state is also terminated.

When the switches 23 and 24 are switched on and off by performing the above switching process, the current from the storage batteries 11 and 12 to the connection point N4 side is allowed, so that the power supply to the electric load 15 continues. Will be done. On the other hand, the current from the connection point N4 side to the storage battery side having the lower voltage value among the storage batteries 11 and 12 is regulated. That is, of the storage batteries 11 and 12, the current from the storage battery side having a high voltage value to the storage battery side having a low voltage value is regulated.

Next, the switching order of the switch units Sa3, Sb3, Sa4, and Sb4 when switching the storage batteries 11 and 12 for supplying the electric power to the electric load 15 will be described with reference to FIGS. 4 to 7. In addition, in FIGS. 4 to 7, only the electric paths L3 and L4, the switches 23 and 24, the storage batteries 11 and 12, and the electric load 15 are shown to simplify the configuration of the in-vehicle power supply system.

First, a case where the voltage value on the lead storage battery 11 side is higher and the switch 23 is changed from the closed state to the open state will be described with reference to FIG. That is, a case will be described in which the storage batteries 11 and 12 for supplying power to the electric load 15 are switched from the lead storage battery 11 to the lithium ion storage battery 12 when the voltage value on the lead storage battery 11 side is higher.

As shown in FIG. 4A, in the initial state, the switch portions Sa3 and Sb3 of the switch 23 are closed (ON), and the switch portions Sa4 and Sb4 of the switch 24 are opened (OFF). As a result, in the initial state, a current flows from the lead-acid battery 11 side to the connection point N4 side, and power is supplied from the lead-acid battery 11 side to the electric load 15. On the other hand, no current flows from the lithium ion storage battery 12 side to the connection point N4 side.

When the switching request is generated, step S104 of the switching process is performed, and as shown in FIG. 4B, the switch unit Sb4 is closed first. As a result, a current flows from the lead storage battery 11 and the lithium ion storage battery 12 side to the connection point N4 side, and power is supplied from both storage batteries 11 and 12 to the electric load 15. Even if the voltage value on the lead-acid battery 11 side is higher than the voltage value on the lithium-ion battery 12 side, no current flows from the connection point N4 side to the lithium-ion storage battery 12 side because the switch section Sa4 is open. .. That is, no current flows from the lead storage battery 11 side to the lithium ion storage battery 12 side via the electric paths L3 and L4.

After that, step S105 of the switching process is performed, and as shown in FIG. 4C, the switch units Sa3 and Sb3 are opened. As a result, the electric path L3 is turned off, and power is not supplied from the lead-acid battery 11 side to the electric load 15, and no current flows from the connection point N4 side to the lead-acid battery 11. On the other hand, since the switch portion Sb4 is in the closed state, a current flows from the lithium ion storage battery 12 side to the connection point N4 side via the switch portion Sb4 and the parasitic diode Da4. As a result, electric power is continuously supplied from the lithium ion storage battery 12 side to the electric load 15.

Then, step S106 of the switching process is performed, and as shown in FIG. 4D, the switch unit Sa4 is closed. As a result, the electric path L4 is energized, and the switching of the switches 23 and 24 is completed.

Next, a case where the voltage value on the lead storage battery 11 side is higher and the switch 23 is changed from the open state to the closed state will be described with reference to FIG. That is, a case will be described in which the storage batteries 11 and 12 for supplying power to the electric load 15 are switched from the lithium ion storage battery 12 to the lead storage battery 11 when the voltage value on the lead storage battery 11 side is higher.

As shown in FIG. 5A, in the initial state, the switch portions Sa3 and Sb3 of the switch 23 are open (OFF), and the switch portions Sa4 and Sb4 of the switch 24 are closed (ON). As a result, in the initial state, a current flows from the lithium ion storage battery 12 side to the connection point N4 side, and power is supplied from the lithium ion storage battery 12 side to the electric load 15. On the other hand, no current flows from the lead-acid battery 11 side to the connection point N4 side.

When the switching request is generated, step S107 of the switching process is performed, and as shown in FIG. 5B, the switch unit Sa4 is first opened. Even in this case as well, since the switch portion Sb4 is in the closed state, a current flows from the lithium ion storage battery 12 side to the connection point N4 side via the switch portion Sb4 and the parasitic diode Da4. That is, electric power is continuously supplied from the lithium ion storage battery 12 side to the electric load 15.

After that, step S108 of the switching process is performed, and as shown in FIG. 5C, the switch units Sa3 and Sb3 are closed. As a result, a current flows from the lead storage battery 11 and the lithium ion storage battery 12 side to the connection point N4 side, and power is supplied from both storage batteries 11 and 12 to the electric load 15. On the other hand, even if the voltage value on the lead storage battery 11 side is higher than the voltage value on the lithium ion storage battery 12, since the switch portion Sa4 is open, current flows from the connection point N4 side to the lithium ion storage battery 12 side. There is no.

After that, step S109 of the switching process is performed, and as shown in FIG. 5D, the switch unit Sb4 is opened. As a result, the electric path L3 is in the energized state, while the electric path L4 is in the energized state, and the switching of the switches 23 and 24 is completed.

Next, a case where the voltage value on the lithium ion storage battery 12 side is higher and the switch 23 is changed from the closed state to the open state will be described with reference to FIG. That is, a case will be described in which the storage batteries 11 and 12 for supplying power to the electric load 15 are switched from the lead storage battery 11 to the lithium ion storage battery 12 when the voltage value on the lithium ion storage battery 12 side is higher.

As shown in FIG. 6A, in the initial state, the switch portions Sa3 and Sb3 of the switch 23 are closed (ON), and the switch portions Sa4 and Sb4 of the switch 24 are opened (OFF). As a result, in the initial state, a current flows from the lead-acid battery 11 side to the connection point N4 side, and power is supplied from the lead-acid battery 11 side to the electric load 15. On the other hand, no current flows from the lithium ion storage battery 12 side to the connection point N4 side.

When the switching request is generated, step S111 of the switching process is performed, and as shown in FIG. 6B, the switch unit Sb3 is first opened. Even in this case, since the switch portion Sa3 is in the closed state, a current flows from the lead storage battery 11 side to the connection point N4 side via the switch portion Sa3 and the parasitic diode Db3. That is, electric power is continuously supplied from the lead storage battery 11 side to the electric load 15.

After that, step S112 of the switching process is performed, and as shown in FIG. 6C, the switch portions Sa4 and Sb4 are closed. As a result, a current flows from the lead storage battery 11 and the lithium ion storage battery 12 side to the connection point N4 side, and power is supplied from both storage batteries 11 and 12 to the electric load 15. On the other hand, even if the voltage value on the lithium ion storage battery 12 side is higher than the voltage value on the lead storage battery 11 side, since the switch portion Sb3 is open, current does not flow from the connection point N4 side to the lead storage battery 11 side. Absent.

After that, step S113 of the switching process is performed, and as shown in FIG. 6D, the switch unit Sa3 is opened. As a result, the electric path L3 is in the energized state, while the electric path L4 is in the energized state, and the switching of the switches 23 and 24 is completed.

Next, a case where the voltage value on the lithium ion storage battery 12 side is higher and the switch 23 is changed from the open state to the closed state will be described with reference to FIG. 7. That is, a case where the storage batteries 11 and 12 for supplying power to the electric load 15 are switched from the lithium ion storage battery 12 to the lead storage battery 11 when the voltage value on the lithium ion storage battery 12 side is higher will be described.

As shown in FIG. 7A, in the initial state, the switch portions Sa3 and Sb3 of the switch 23 are open (OFF), and the switch portions Sa4 and Sb4 of the switch 24 are closed (ON). As a result, in the initial state, a current flows from the lithium ion storage battery 12 side to the connection point N4 side, and power is supplied from the lithium ion storage battery 12 side to the electric load 15. On the other hand, no current flows from the lead-acid battery 11 side to the connection point N4 side.

When the switching request is generated, step S114 of the switching process is performed, and as shown in FIG. 7B, the switch unit Sa3 is closed first. As a result, a current flows from the lead storage battery 11 and the lithium ion storage battery 12 side to the connection point N4 side, and power is supplied from both storage batteries 11 and 12 to the electric load 15. Even if the voltage value on the lithium ion storage battery 12 side is higher than the voltage value on the lead storage battery 11 side, since the switch unit Sb3 as a specific switch unit is open, the current from the connection point N4 side to the lead storage battery 11 side. Does not flow. That is, no current flows from the lithium ion storage battery 12 side to the lead storage battery 11 side via the electric paths L3 and L4.

After that, step S115 of the switching process is performed, and as shown in FIG. 7C, the switch units Sa4 and Sb4 are opened. As a result, the electric path L4 is turned off, and power is not supplied from the lithium ion storage battery 12 side to the electric load 15, and no current flows from the connection point N4 side to the lithium ion storage battery 12. On the other hand, since the switch portion Sa3 is in the closed state, a current flows from the lead storage battery 11 side to the connection point N4 side via the switch portion Sa3 and the parasitic diode Db3. As a result, electric power is continuously supplied from the lead storage battery 11 side to the electric load 15.

Then, step S116 of the switching process is performed, and as shown in FIG. 7D, the switch unit Sb3 is closed. As a result, the electric path L3 is energized, and the switching of the switches 23 and 24 is completed.

According to the present embodiment described in detail above, the following excellent effects can be obtained.

The storage batteries 11 and 12 are switched through a switching intermediate state in which the switch units Sb3 and Sa4 connected in parallel with the parasitic diodes Db3 and Da4 that regulate the flow of current from the connection point N4 side to the storage batteries 11 and 12 are opened. .. In this switching intermediate state, current is allowed to flow from the storage batteries 11 and 12 sides to the connection point N4 side via the parasitic diodes Db3 and Da4, but the current flows to the opposite side (storage batteries 11 and 12 sides). Flow is regulated. Therefore, even if the switch units other than the switch units Sb3 and Sa4 are closed and power is supplied from both storage batteries 11 and 12 to the electric load 15, the voltage difference between the storage batteries 11 and 12 will eventually cause the power to be supplied. It is possible to regulate the flow of current to the storage battery side. As a result, when switching the switches 23 and 24, it is possible to regulate the flow of an excessive current that exceeds the allowable current amount of each switch unit Sa3, Sb3, Sa4, Sb4, and protect the switches 23 and 24.

When both the electric paths L3 and L4 are energized, when there is a voltage difference between the storage batteries 11 and 12, a current flows from the connection point N4 side to the storage battery side having a low voltage value via the switches 23 and 24. On the other hand, no current flows from the connection point N4 side to the storage batteries 11 and 12 sides having a high voltage value.

Therefore, in the switching intermediate state, the switch unit connected in parallel with the parasitic diode that regulates the current from the connection point N4 side to the storage battery side with a low voltage value is opened, and the other switch units are closed. I decided to put it in a state. As a result, an excessive current is applied to the switches 23 and 24 provided in the electric paths L3 and L4 between the electric load 15 and the storage batteries 11 and 12 having a low voltage value from the connection point N4 side to the storage batteries 11 and 12 side. You can regulate the flow. Therefore, the switches 23 and 24 that need to be protected can be appropriately protected.

No current flows from the connection point N4 side to the storage batteries 11 and 12 sides having a high voltage value. That is, it is not necessary to open the switch portion provided on the storage battery side having a high voltage value. Therefore, by comparing the voltage values and opening the switch section connected in parallel with the parasitic diode that regulates the current to the storage battery side with the low voltage value, it is determined which switch section does not need to be opened. It can be prevented from opening.

The lead storage battery 11 and the electric load 13 are connected in parallel to the external terminal P0. When electric power is temporarily supplied from the electric load 13, the voltage value on the lead storage battery 11 side may be temporarily lowered. That is, the voltage value at the external terminal P0 may be lower than that on the lithium ion storage battery 12 side due to the influence of the electric load 13. In this case, if the switches 23 and 24 are switched while the electric paths L3 and L4 are both energized, an excessive current may flow with respect to the allowable current amount of the switches 23 and 24 due to the power request of the electric load 13. There is. Especially when the power demand of the electric load 13 is large, the possibility becomes high.

However, when power is requested from the electric load 13 by executing the switching process as described above, even if the switches 23 and 24 are switched, the current flows to the lead storage battery 11 side via the switches 23 and 24. Can be regulated. That is, each switch unit Sa3, Sb3, Sa4, Sb4 can be appropriately opened and closed regardless of the power request from the electric load 13.

A lead storage battery 11 and a lithium ion storage battery 12 are connected in parallel to the rotary electric machine 14 via electric paths L1 and L2. Therefore, when power is supplied from the rotary electric machine 14, the voltage value on either of the storage batteries 11 and 12 may be temporarily increased. However, when power is supplied from the rotary electric machine 14 by executing the switching process as described above, even if the switches 23 and 24 are switched, the connection point N4 side is used via the switches 23 and 24. It is possible to regulate the flow of current to any of the storage batteries 11 and 12. That is, each switch unit Sa3, Sb3, Sa4, Sb4 can be appropriately opened and closed regardless of the state of the rotary electric machine 14 and the opening / closing state of the switches 21 and 22. Therefore, control becomes easy.

A rotating electric machine 14 as a power supply source other than the storage batteries 11 and 12 and an electric load 13 are connected to the storage batteries 11 and 12, and even if there is a power supply or a power request from them, the storage batteries 11 and 12 are used. When switching, no current flows from the connection point N4 side to the storage battery side having a low voltage. That is, each switch unit Sa3, Sb3, Sa4, Sb4 can be opened and closed without considering the situation of the rotary electric machine 14 and the electric load 13. Therefore, by executing this switching process, the switches 23 and 24 can be quickly and appropriately switched at the time of abnormality determination.

The control unit 51 opens the switch unit connected in parallel with the parasitic diode that allows the current to the connection point N4 side and regulates the current to the opposite side among the switch units on the storage battery side having a low voltage value. After the state is set, the other switch parts are closed. As a result, even when the storage batteries 11 and 12 for supplying electric power to the electric load 15 are switched, the electric power can be continuously supplied to the electric load 15. Therefore, the electric load 15 can include a constant voltage load that requires a constant voltage of electric power.

(Second Embodiment)
In the second embodiment, the control unit 51 opens all the switch units Sb3 and Sa4, and then closes the switch unit on the storage battery side having a high voltage value among the switch units Sb3 and Sa4, and in that state, The switches 23 and 24 are switched.

That is, when the switches 23 and 24 are requested to be switched, the control unit 51 opens all the switch units Sb3 and Sa4 and all the other switch units Sa3 and Sb4 regardless of the voltage difference between the storage batteries 11 and 12. Make it closed (make it in the intermediate state of switching). The control unit 51 identifies the storage battery side having a high voltage value based on the current or potential difference of the switches 23 and 24, and closes the switch on the storage battery side having a high voltage value. After that, the control unit 51 opens the switch unit provided in the electric paths L3 and L4 in which the energization is cut off. At that time, of the switch portions Sb3 and Sa4, the switch portions provided in the electric paths L3 and L4 to be energized are closed. Hereinafter, this switching process will be described in detail based on FIG.

The control unit 51 determines whether or not a switching request has occurred (step S301). If no switching request has occurred (step S301: NO), the control unit 51 ends the switching process. When a switching request has been generated (step S301: YES), the control unit 51 determines whether or not the switching request is for opening the closed switch 23 (step S302).

When the request is for switching to open the switch 23 (step S302: YES), the control unit 51 releases the switch unit Sb3 of the switch 23 (step S303). Further, the control unit 51 closes the switch unit Sb4 of the switch 24 (step S304). That is, the control unit 51 closes the switch units Sb4 in order to open the switch units Sb3 and Sa4 and to close the switch units Sa3 and Sb4 (to bring them into the switching intermediate state).

After that, the current flowing through the switches 23 and 24 is acquired (step S305). The switches 23 and 24 are provided with current detection circuits (not shown) as detection units for detecting the current flowing through the switches 23 and 24, and the control unit 51 is provided with the switches 23 and 24 from the current detection circuits. Get each of the currents of.

Then, the control unit 51 determines whether or not the current flowing through the switch 23 is larger than the current flowing through the switch 24 (step S306). That is, the storage battery side having the higher voltage value among the storage batteries 11 and 12 is determined based on the current ratio supplied to the electric load 15. Although the currents of the switches 23 and 24 are detected and compared, the voltage values of the storage batteries 11 and 12 may be detected and compared. Further, the currents flowing through the parasitic diodes Db3 and Da4 may be detected and compared.

When the current flowing through the switch 23 is larger (step S306: YES), the control unit 51 closes the switch unit Sb3 (step S307). That is, since the voltage value on the lead storage battery 11 side is higher than that on the lithium ion storage battery 12, the control unit 51 closes the switch unit Sb3. As a result, it is possible to prevent a large current from continuing to flow in the parasitic diode Db3.

Then, the control unit 51 releases the switch units Sa3 and Sb3 of the switch 23 that are requested (determined) to be released (step S308). The control unit 51 closes the switch unit Sa4 (step S309), and ends the switching process.

When the current flowing through the switch 24 is larger (step S306: No), the control unit 51 closes the switch unit Sa4 (step S310). That is, since the voltage value on the lead storage battery 11 side is lower than that on the lithium ion storage battery 12, the control unit 51 closes the switch unit Sa4. As a result, it is possible to prevent a large current from continuing to flow through the parasitic diode Da4.

Then, the control unit 51 releases the switch unit Sa3 of the switch 23, which is requested (determined) to be released (step S311), and ends the switching process.

If it is not a switching request to open the switch 23 (step S302: NO), the control unit 51 releases the switch unit Sa4 of the switch 24 (step S312). The control unit 51 closes the switch unit Sa3 of the switch 23 (step S313). That is, the control unit 51 closes the switch unit Sa3 in order to open the switch units Sb3 and Sa4 and to close the switch units Sa3 and Sb4 (to bring them into the switching intermediate state).

After that, the currents of the switches 23 and 24 are acquired (step S314). Then, the control unit 51 determines whether or not the current flowing through the switch 23 is larger than the current flowing through the switch 24 (step S315).

When the current flowing through the switch 23 is larger (step S315: YES), the control unit 51 closes the switch unit Sb3 (step S316). Then, the control unit 51 releases the switch unit Sb4 of the switch 24 that is requested (determined) to be released (step S317), and ends the switching process.

When the current flowing through the switch 24 is larger (step S315: No), the control unit 51 closes the switch unit Sa4 (step S318). Then, the control unit 51 releases the switch units Sa4 and Sb4 of the switch 24 that are requested (determined) to be released (step S319). After that, the control unit 51 closes the switch unit Sb3 (step S320), and ends the switching process.

According to the second embodiment described in detail above, the following excellent effects can be obtained.

When switching the switches 23 and 24, it is possible to regulate the flow of current from the connection point N4 to the storage batteries 11 and 12 while continuously supplying electric power from the storage batteries 11 and 12 to the electric load 15. Further, when the switches 23 and 24 are requested to be switched, the switch units Sb3 and Sa4 are both opened and the other switch units Sa3 and Sb4 are closed, and then the voltage value on any of the storage batteries 11 and 12 is changed. Determine if it is high. Therefore, it is possible to secure time for determination. Further, based on the currents of the switches 23 and 24, the storage batteries 11 and 12 having a high voltage value are determined, and among the switch units Sa4 and Sb4, the switch units on the storage batteries 11 and 12 having a high voltage value are closed. Therefore, it is possible to suppress the continuous flow of a large current through the parasitic diodes Db3 and Da4.

(Other embodiments)
The present invention is not limited to the above embodiment, and may be implemented as follows, for example. In the following, the parts that are the same or equal to each other in each embodiment are designated by the same reference numerals, and the description thereof will be incorporated for the parts having the same reference numerals.

In the above embodiment, the lead-acid battery 11 and the electric load 13 are connected to the external terminal P0, the rotary electric machine 14 is connected to the external terminal P1, and the electric load 15 is connected to the external terminal P2. However, it may be applied to other in-vehicle power supply systems. For example, it may be applied to an in-vehicle power supply system in which the storage batteries 11 and 12 are connected in parallel to the alternator 70 as a generator and the storage batteries 11 and 12 are connected in parallel to the electric load 15. ..

This in-vehicle power supply system will be described in detail. As shown in FIG. 9, the lead storage battery 11, the alternator 70 as a generator, the electric load 13 and the like are connected to the external terminal P0 of the battery unit U, and the electric load 15 and the like are connected to the external terminal P2. In the battery unit U, a switch 23 is provided in the electric path L3 between the external terminals P0 and P2, and a switch 24 is provided in the electric path L4 between the lithium ion storage battery 12 and the external terminal P2. Further, the battery unit U is provided with a bypass path B2 that bypasses the switch 23, and a bypass opening / closing circuit RE2 is provided in the bypass path B2.

Even in such a power supply system, by performing switching processing, it is possible to regulate the flow of current from the electric load 15 side to any of the storage batteries 11 and 12 while continuously supplying electric power to the electric load 15. Can be done.

-In the above embodiment, the lead storage battery 11 is provided as the first storage battery and the lithium ion storage battery 12 is provided as the second storage battery, but this may be changed. As the second storage battery, a high-density storage battery other than the lithium ion storage battery 12, for example, a nickel-hydrogen battery may be used. In addition, the same storage battery (for example, lead storage battery, lithium ion storage battery, etc.) can be used as the first storage battery and the second storage battery.

-In the second embodiment, when the switch to be opened is a switch on the storage battery side having a high voltage value in the switching intermediate state, among the switch portions of the switch, from the connection point N4 side to the storage batteries 11 and 12 sides. The switch may be switched as it is without temporarily closing the switch unit connected in parallel to the parasitic diode that regulates the current. That is, when the switch to be opened is a switch on the storage battery side having a high voltage value in the intermediate state of switching, the control unit 51 opens all the switch parts of the switch while closing all the switch parts of the switch to be closed. It may be.

Specifically, when the determination result in step S306 of the switching process is affirmative (when the current flowing through the switch 23 is larger), the control unit 51 is requested (determined) to open the switch of the switch 23. The part Sa3 is opened, and the switch part Sa4 is closed to end the switching process. By doing so, it is possible to omit the opening / closing process of closing the switch unit Sb3 once and then opening it, and it is possible to shorten the time for switching the switch.

Similarly, when the determination result in step S315 of the switching process is negative (when the current flowing through the switch 24 is larger), the control unit 51 is requested (determined) to open the switch unit Sb4 of the switch 24. Is opened, the switch unit Sb3 is closed, and the switching process is completed. By doing so, it is possible to omit the opening / closing process of closing the switch unit Sa4 once and then opening it, and it is possible to shorten the time for switching the switch.

-It is also possible to use the power supply system for purposes other than vehicles.

The control unit 51 opens the switch units Sb3 and Sa4 connected in parallel with the parasitic diodes Db3 and Da4 that regulate the current from the electric load 15 side to the storage batteries 11 and 12, and then switches 23, 24 may be switched. That is, when switching of the switches 23 and 24 is requested, both the switch units Sb3 and Sa4 are opened and the other switch units Sa3 and Sb4 are closed regardless of the voltage difference between the storage batteries 11 and 12. After that, the control unit 51 opens the switch unit provided in the electric paths L3 and L4 in which the energization is cut off. At that time, it is desirable to close the switch portions provided in the electric paths L3 and L4 to be energized among the switch portions Sb3 and Sa4. Hereinafter, this switching process will be described in detail with reference to FIG.

The control unit 51 determines whether or not a switching request has occurred (step S201). If no switching request has occurred (step S201: NO), the control unit 51 ends the switching process.

When a switching request has been generated (step S201: YES), the control unit 51 determines whether or not the switching request is for opening the closed switch 23 (step S202).

When the request is for switching to open the switch 23 (step S202: YES), the control unit 51 releases the switch unit Sb3 of the switch 23 (step S203).

Further, the control unit 51 closes the switch unit Sb4 of the switch 24 (step S204). That is, the control unit 51 closes the switch units Sb4 in order to open the switch units Sb3 and Sa4 and to close the switch units Sa3 and Sb4 (to bring them into the switching intermediate state).

After a predetermined time has elapsed from step S204, the control unit 51 releases the switch unit Sa3 of the switch 23 that is requested (determined) to be released (step S205). The control unit 51 closes the switch unit Sa4 (step S206) and ends the switching process.

If it is not a switching request to open the switch 23 (step S202: NO), the control unit 51 releases the switch unit Sa4 of the switch 24 (step S207). The control unit 51 closes the switch unit Sa3 of the switch 23 (step S208). That is, the control unit 51 closes the switch unit Sa3 in order to open the switch units Sb3 and Sa4 and to close the switch units Sa3 and Sb4 (to bring them into the switching intermediate state).

After a predetermined time has elapsed from step S208, the control unit 51 releases the switch unit Sb4 of the switch 24 that is requested (determined) to be released (step S209). Further, the control unit 51 closes the switch unit Sa3 (step S210), and ends the switching process. As a result, the voltage value on the lead storage battery 11 side and the voltage value on the lithium ion storage battery 12 side may be compared.

11 ... Lead storage battery, 12 ... Lithium ion storage battery, 15 ... Electric load, 21 to 24 ... Switch, 21a to 24a, 21b to 24b ... Semiconductor switch, 51 ... Control unit, Da1 to Da4, Db1 to Db4 ... Parasitic diode, Sa1 ~ Sa4, Sb1 to Sb4 ... Switch unit, U ... Battery unit.

Claims (6)

In the power supply device (U) applied to the power supply system in which the first storage battery (11) and the second storage battery (12) are connected in parallel with respect to the electric load (15).
First opening / closing portions (21, 23) provided on the first storage battery side of the connection points (N1, N4) with the electric load in the electric path between the first storage battery and the second storage battery.
Second opening / closing portions (22, 24) provided on the second storage battery side of the connection point in the electric path, and
A control unit (51) that controls the first opening / closing unit and the second opening / closing unit,
A detection unit for detecting a current flowing through the first opening / closing unit and a current flowing through the second opening / closing unit is provided.
The first opening / closing part and the second opening / closing part are configured by connecting a first switch (21a to 24a) and a second switch (21b to 24b) in series, respectively.
The first switch and the second switch each have a diode (Da1 to Da4, Db1 to Db4) and a switch unit (Sa1 to Sa4, Sb1 to Sb4) connected in parallel with the diode.
The diode of the first switch and the diode of the second switch are provided in opposite directions to each other.
When the control unit switches the supply of electric current to the electric load between the first storage battery and the second storage battery, the control unit has the switch unit of the first opening / closing unit and the second opening / closing unit. all the switch units connected current diodes for regulating the said switch unit is connected to the diode for regulating the current to the first battery side from the connection point side and from the connection point side to the second battery side After the switching intermediate state in which all the switch parts other than the switch part are closed in the open state , the first opening / closing part and the second opening / closing part are selected based on the current detected by the detection part. Identify the opening and closing part where a lot of current is flowing,
A power supply device that controls each of the opening / closing portions so as to switch between the first storage battery and the second storage battery in a state where all the switching portions of the specified opening / closing portion are closed . When the specified opening / closing unit is an opening / closing unit that is required to be opened when switching between the first storage battery and the second storage battery, the control unit has the switch unit included in the specified opening / closing unit. all without the closed state, as all opened the switch unit in which the specified closing unit has a power supply device according to claim 1 for switching between the second battery and the first battery. The electrical load includes a constant voltage load that requires constant voltage power.
The power supply device according to claim 1 or 2 , wherein an electric load (13) that temporarily requires electric power is connected to either the first storage battery or the second storage battery in addition to the constant voltage load. The power supply device according to any one of claims 1 to 3 , wherein a generator (14,70) for supplying electric power is connected to either the first storage battery and the second storage battery. The power supply device according to any one of claims 1 to 4 , wherein the control unit switches between the first storage battery and the second storage battery when it is determined that an abnormality has occurred in the power supply device. In a power supply system including an electric load (15) and a first storage battery (11) and a second storage battery (12) connected in parallel to the electric load.
First opening / closing portions (21, 23) provided on the first storage battery side of the connection points (N1, N4) with the electric load in the electric path between the first storage battery and the second storage battery.
Second opening / closing portions (22, 24) provided on the second storage battery side of the connection point in the electric path, and
A control unit (51) that controls the first opening / closing unit and the second opening / closing unit,
A detection unit for detecting a current flowing through the first opening / closing unit and a current flowing through the second opening / closing unit is provided.
The first opening / closing part and the second opening / closing part are configured by connecting a first switch (21a to 24a) and a second switch (21b to 24b) in series, respectively.
The first switch and the second switch each have a diode (Da1 to Da4, Db1 to Db4) and a switch unit (Sa1 to Sa4, Sb1 to Sb4) connected in parallel with the diode.
The diode of the first switch and the diode of the second switch are provided in opposite directions to each other.
When the control unit switches the supply of electric current to the electric load between the first storage battery and the second storage battery, the control unit has the switch unit of the first opening / closing unit and the second opening / closing unit. all the switch units connected current diodes for regulating the said switch unit is connected to the diode for regulating the current to the first battery side from the connection point side and from the connection point side to the second battery side and the open state, after the switching intermediate state that all the switch portions other than the switch portion closed, based on the detected current by the detecting unit, among the second closing part and the first closing part, more Identify the opening and closing part where a lot of current is flowing,
A power supply system that controls each of the opening / closing portions so as to switch between the first storage battery and the second storage battery in a state where all the switching portions of the specified opening / closing portion are closed .

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