JP7700615B2 - Vehicle battery charging device - Google Patents

Description

The present invention relates to a battery charging device for a vehicle equipped with a battery and an external charging device capable of performing external charging by charging the battery using a power source outside the vehicle.

Conventionally, vehicles have been known that are equipped with a motor as a drive source and a battery that supplies power to various electrical devices, and that allow the battery to be charged by a power source outside the vehicle.

For example, Patent Document 1 discloses a vehicle that includes a motor for driving, a high-voltage battery that supplies power to the motor, a charger that can charge the high-voltage battery from an external power source, a low-voltage battery that has a lower output voltage than the high-voltage battery, and a DC/DC converter, and is configured so that power is supplied from the high-voltage battery to the low-voltage battery via the DC/DC converter. Here, in the vehicle of Patent Document 1, even when the high-voltage battery is being charged by an external power source, the high-voltage battery and the DC/DC converter are electrically connected and the DC/DC converter is driven so that a portion of the power supplied to the high-voltage battery is supplied to the low-voltage battery.

Patent No. 6288134

As in Patent Document 1, if the battery and other electrical devices are electrically connected when the battery is being charged by an external power source, part of the power supplied to the battery can be supplied to the other electrical devices while the battery is being charged, allowing them to operate appropriately. However, if the battery and other electrical devices are simply electrically connected when a request to charge the battery is issued, power will be supplied from the battery to the electrical devices if a failure occurs in the external power source device, etc., and the power source device is unable to supply power to the battery appropriately. This can cause the battery to over-discharge.

The present invention was made in consideration of the above circumstances, and aims to provide a vehicle battery charging device that can prevent over-discharging of the battery.

In order to solve the above problem, the present invention provides a battery charging device for a vehicle equipped with a battery and an external charging device capable of performing external charging, in which the battery is charged with power supplied from an external power source outside the vehicle, comprising an electrical device supplied with power from the battery, a disconnecting device capable of electrically connecting and disconnecting the battery and the electrical device, and a control device for controlling the disconnecting device, wherein when a request for external charging is issued, if a connection prohibition condition is met in which the SOC of the battery is less than a predetermined determination value and the number of charging failures, which is the number of times the external charging has failed, is equal to or greater than a predetermined determination number, the control device controls the disconnecting device so that the electrical connection between the battery and the electrical device is cut off, and if the connection prohibition condition is not met, the control device controls the external charging device to start the external charging and controls the disconnecting device so that the battery and the electrical device are electrically connected (claim 1).

In the present invention, when a request for external charging is made in a case where the connection prohibition condition is not satisfied, the external charging device is controlled to start external charging, and the battery and the electric device are electrically connected. Therefore, power can be appropriately supplied to the electric device when external charging is performed.

Moreover, in the present invention, when the battery SOC is low and the number of external charging failures is equal to or exceeds the determination number, and it is considered that the external charging-related equipment (external power supply equipment or external charging device for the vehicle) is malfunctioning and power is not being properly supplied from the external power source to the battery, the electrical connection between the battery and the electrical equipment is cut off. This makes it possible to prevent power from being supplied to the electrical equipment from the battery when the battery SOC is low and power is not being supplied to the battery from the external power source, and reliably prevents the battery SOC from decreasing further due to power supply to the electrical equipment, i.e., prevents the battery from being over-discharged.

As a configuration for determining that the external charging has failed, the control device may determine that the external charging has failed if power is not supplied to the battery from a power source outside the vehicle even after a predetermined determination time has elapsed since the control device controlled the external charging device to start the external charging (claim 2).

In the above configuration, preferably, the electrical device includes a low-voltage battery with a lower output voltage than the battery, and a DC/DC converter that steps down the power from the battery and charges the low-voltage battery, and the control device activates the DC/DC converter when a request for external charging is issued (Claim 3).

With this configuration, the low-voltage battery can be charged while external charging is being performed, and when the battery's SOC is low and the external charging-related equipment is broken as described above, the power supply from the battery to the low-voltage battery via the DC/DC converter is stopped, preventing the battery from being over-discharged due to the power supply to the low-voltage battery.

The external charging device may be an AC external charging unit that has an AC/DC converter that converts AC current to DC current and charges the battery with output power from an AC power source outside the vehicle (Claim 4).

The external charging device may also be a device equipped with a DC external charging unit that charges the battery with output power from a DC power source outside the vehicle (claim 5).

In the above configuration, preferably, the battery is electrically connected to the external charging device via an electric equipment circuit in which the electric equipment is provided, the disconnecting device disconnects the electric connection between the battery and the electric equipment by disconnecting the electric connection between the electric equipment circuit and the battery, and the control device resets the number of charging failures to 0 when the number of charging failures is 1 or more and the SOC of the battery becomes equal to or greater than a predetermined second judgment value higher than the judgment value (claim 6).

With this configuration, when the battery's SOC recovers and there is no longer any risk of over-discharging the battery, the connection between the battery and the electrical equipment circuit, and therefore the electrical connection between the battery and the external charging device, can be re-established, so that charging of the battery from a power source outside the vehicle can be resumed. This ensures that the battery can be charged from a power source outside the vehicle while preventing over-discharging of the battery.

As described above, the vehicle battery charging device of the present invention can prevent the battery from being over-discharged.

1 is a diagram showing a schematic configuration of a vehicle equipped with a battery charging device according to an embodiment of the present invention; FIG. 2 is a block diagram showing the relationship between the controllers. 1 is a block diagram showing a control configuration for external charging control. 4 is a flowchart showing a flow of control performed when a request for external charging is issued. 4 is a time chart showing the change over time of each parameter when a request for external charging is issued. 4 is a time chart showing the change over time of each parameter when a request for external charging is issued. 4 is a time chart showing the change over time of each parameter when a request for external charging is issued. FIG. 2 is a diagram illustrating a schematic flow of electricity during external charging. FIG. 13 is a diagram illustrating a schematic diagram of the flow of electricity when external charging fails.

(1) Overall Configuration of Vehicle A description will be given of a vehicle battery charging device according to an embodiment of the present invention. Fig. 1 is a diagram showing a schematic configuration of a vehicle 1 equipped with a battery charging device 100 according to this embodiment. The vehicle 1 is, for example, a four-wheeled automobile.

The vehicle 1 has a high-voltage battery 2, an AC external charging device 40, a DC external charging device 50, and a plurality of high-voltage devices 90 including a low-voltage battery 3 with a lower output voltage than the high-voltage battery 2, which receives power supply from the high-voltage battery 2. The vehicle 1 also has a plurality of controllers including a microprocessor or the like that control each part of the vehicle 1. The high-voltage battery 2 corresponds to the "battery" in the claims, and the high-voltage devices 90 correspond to the "electrical devices" in the claims. The AC external charging device 40 corresponds to the "AC external charging unit" in the claims, the DC external charging device 50 corresponds to the "DC external charging unit" in the claims, and the AC external charging device 40 and the DC external charging device 50 correspond to the "external charging devices" in the claims.

(Battery)
In this embodiment, a Li battery (lithium battery) is mounted on the vehicle 1 as the high-voltage battery 2. For example, the high-voltage battery 2 has a plurality of battery modules each made of 12 battery cells connected in 2 parallel×6 series, and these battery modules are connected in series. Also, in this embodiment, a lead battery is mounted on the vehicle 1 as the low-voltage battery 3. For example, the nominal voltage of the high-voltage battery 2 is 24V, and the nominal voltage of the low-voltage battery 3 is 12V.

The high-voltage battery 2 is provided with a battery current sensor SN1 that detects the battery current, which is the current flowing through the high-voltage battery 2, and a battery voltage sensor SN2 that detects the output voltage of the high-voltage battery 2.

(High voltage equipment)
In addition to the low-voltage battery 3, the vehicle 1 is provided with a motor 4, a generator 5, an inverter 6, a converter 7, a DC/DC converter 8, a PTC heater 9, and an electric compressor 10 as high-voltage equipment 90. These are provided on the same circuit. Hereinafter, the circuit in which these high-voltage equipment 90 are provided will be referred to as a high-voltage circuit 30 where appropriate. This high-voltage circuit 30 corresponds to the "electrical equipment circuit" in the claims.

The high voltage circuit 30 has a P-side high voltage line 31a, which is a positive side line connected to the positive terminal 2a of the high voltage battery 2, and an N-side high voltage line 31b, which is a negative side line connected to the negative terminal 2b of the high voltage battery 2. Hereinafter, the P-side high voltage line 31a and the N-side high voltage line 31b will be collectively referred to as the high voltage lines 31 where appropriate.

The inverter 6, converter 7, DC/DC converter 8, PTC heater 9 and electric compressor 10 are each connected to a high voltage line 31. The motor 4 is connected to the high voltage line 31 via the inverter 6. The generator 5 is connected to the high voltage line 31 via the converter 7.

The motor 4 rotates by receiving power from the high-voltage battery 2. The motor 4 is mounted on the vehicle 1 as the driving source of the vehicle 1, and the output of the motor 4 is transmitted to the wheels (not shown) via the driving force transmission device 20.

The generator 5 is a power generation device for charging the high-voltage battery 2. The vehicle 1 of this embodiment is a series-type hybrid vehicle, and the vehicle 1 is equipped with an engine 22 that drives the generator 5. In other words, the generator 5 is rotated and driven by the engine 22 to generate electricity, and the electricity generated by the generator 5 is supplied to the high-voltage battery 2. The engine 22 is, for example, a rotary engine. The generator 5 is also connected to the wheels via a driving force transmission device 20, and the vehicle 1 is capable of regenerating energy during deceleration.

The inverter 6 is a device that converts DC current into AC current, and converts the DC current from the high-voltage battery 2 into AC current and supplies it to the motor 4. The converter 7 is a device that converts AC current into DC current, and converts the AC current generated by the generator 5 into DC current and supplies it to the high-voltage battery 2.

The DC/DC converter 8 is a device that steps down the input power and outputs it, stepping down the output voltage of the high-voltage battery 2 and supplying it to the low-voltage battery 3. The DC/DC converter 8 is equipped with a microcomputer, and the operation and stopping of the DC/DC converter 8 are controlled by this microcomputer. This microcomputer operates by receiving power from the low-voltage battery 3.

The PTC heater 9 and the electric compressor 10 constitute the air conditioning system 11 of the vehicle 1. Specifically, the PTC heater 9 is a device for heating the interior of the vehicle 1, and the electric compressor 10 is a device for cooling the interior of the vehicle 1. In this embodiment, a cooling plate (not shown) is provided for cooling the high-voltage battery 2, and the electric compressor 10 also cools this cooling plate.

The high-voltage circuit 30 and the high-voltage battery 2 are connected via a contactor. The contactor is an electromagnetic switch that includes an electromagnet, and it makes and breaks the electrical connection between two contacts depending on the power supplied. When the contactor is closed, the two contacts are electrically connected and in a state where electricity flows, and when the contactor is opened, the two contacts are electrically cut off and in a state where electricity does not flow.

Specifically, the vehicle 1 is provided with a P-side main contactor 71 having two contacts connected to the positive terminal 2a of the high-voltage battery 2 (specifically, the positive battery line 2d connected to the positive terminal 2a) and the P-side high-voltage line 31a, and the P-side main contactor 71 electrically connects and disconnects the positive terminal 2a of the high-voltage battery 2 and the P-side high-voltage line 31a. The vehicle 1 is also provided with an N-side main contactor 72 having two contacts connected to the negative terminal 2b of the high-voltage battery 2 (specifically, the negative battery line 2e connected to the negative terminal 2b) and the N-side high-voltage line 31b, and the N-side main contactor 72 electrically connects and disconnects the negative terminal 2b of the high-voltage battery 2 and the N-side high-voltage line 31b. These two P-side main contactors 71 and N-side main contactors 72 connect and disconnect the high voltage line 31, and therefore the high voltage circuit 30 and the high voltage equipment 90, and the high voltage battery 2. The P-side main contactor 71 and N-side main contactor 72 correspond to the "disconnecting device" in the claims.

In addition, in this embodiment, a precharge contactor 73 is provided as a contactor, which is arranged in parallel with the N-side main contactor 72, and the electrical connection between the negative terminal 2b of the high-voltage battery 2 and the N-side high-voltage line 31b is also made and broken by the precharge contactor 73. However, a resistor 74 is provided in series with the line in which the precharge contactor 73 is provided, and the electrical resistance between the terminal of the high-voltage battery 2 and the high-voltage line 31 via the precharge contactor 73 is made larger than the electrical resistance between the terminal of the high-voltage battery 2 and the high-voltage line 31 via the precharge contactor 73 and the N-side main contactor 72.

(AC external charging device 40)
The AC external charging device 40 is a device for supplying electric power from an AC power source outside the vehicle to the high-voltage battery 2 to charge the high-voltage battery 2. The AC external charging device 40 has an OBC (On Board Charger) 41, an AC charging inlet 42, and a pair of OBC contactors 44a, 44b.

The OBC 41 is a device that converts the AC current supplied from outside the vehicle into a current that can be used to properly charge the high-voltage battery 2, and has an AC/DC converter 43 that converts the AC current into a DC current. The OBC 41 operates by receiving power from the low-voltage battery 3.

The AC charging inlet 42 is a device for electrically connecting a cable connected to an external AC power source 300 to the OBC 41. The AC charging inlet 42 is electrically connected to the OBC 41, and is configured so that a connector (hereinafter, appropriately referred to as an AC connector) provided at the end of the cable is inserted and fitted into the inlet 42.

The OBC contactors 44a and 44b are contactors that electrically connect and disconnect the OBC 41 and the high voltage line 31 (high voltage circuit 30). The two contacts of one OBC contactor 44a (hereinafter referred to as the P-side OBC contactor 44a) are connected to the positive side line 43a of the OBC 41 and the P-side high voltage line 31a, respectively, and the electrical connection between the positive side line 43a of the OBC 41 and the P-side high voltage line 31a is cut off by this P-side OBC contactor 44a. The two contacts of the other OBC contactor 44b (hereinafter referred to as the N-side OBC contactor 44b) are connected to the negative side line 43b of the OBC 41 and the N-side high voltage line 31b, respectively, and the N-side OBC contactor 44b electrically disconnects the negative side line 43b of the OBC 41 and the N-side high voltage line 31b.

(DC external charging device 50)
The DC external charging device 50 is a device for supplying electric power from a DC power source outside the vehicle to the high-voltage battery 2 to charge the high-voltage battery 2. The DC external charging device 50 has a DC charging inlet 52 and a pair of QBC contactors 51a, 51b.

The DC charging inlet 52 is a device for electrically connecting a cable connected to a DC power source 301 outside the vehicle to the high voltage line 31. The DC charging inlet 52 is configured so that a connector (hereinafter, appropriately referred to as a DC connector) provided at the end of the cable is inserted and engaged with it.

The QBC contactors 51a and 51b are contactors that electrically connect and disconnect the DC charging inlet 52 and the high voltage line 31. The two contacts of one QBC contactor 51a (hereinafter referred to as the P-side QBC contactor 51a) are connected to the positive side line 52a of the DC charging inlet 52 and the P-side high voltage line 31a, respectively, and the P-side QBC contactor 51a electrically connects and disconnects the positive side line 52a of the DC charging inlet 52 and the P-side high voltage line 31a. The two contacts of the other QBC contactor 51b (hereinafter referred to as the N-side QBC contactor 51b) are connected to the negative side line 52b of the DC charging inlet 52 and the N-side high voltage line 31b, respectively, and the N-side QBC contactor 51b electrically disconnects the line 52b on the negative side of the DC charging inlet 52 and the N-side high voltage line 31b.

(controller)
FIG. 2 is a block diagram showing the relationship between the controllers mounted on the vehicle 1. The vehicle 1 includes, as controllers, a C-BCM (Center-Body Control Module) 200, a PCM (Power Control Module) 201, an ECM (Engine Control Module) 202, a DMCM (Driver Moor Control Module) 203, an SGCM (Starter Generator Control Module) 204, a BCCM (Battery Charger Control Module) 205, a BECM (Battery Energy Control Module) 206, an ESU (Electric Supply These controllers 200 to 207 are connected to the low-voltage battery 3 and operate by receiving power from the low-voltage battery 3.

Each of the controllers 200-207 mainly performs the following controls: The C-BCM 200 controls the doors, windows, etc. The PCM 201 controls the drive system of the vehicle 1. The ECM 202 controls the engine 22. The DMCM 203 controls the inverter 6. The SGCM 204 controls the converter 7. The BCCM 205 controls the OBC 41. The BECM 206 controls the high-voltage battery 2. The ESU 207 controls the air conditioning and heating device 11. These controllers 200-207 exchange signals with each other. For example, these controllers 200-207 communicate with each other via CAN (Controller Area Network).

Here, the HMI device 208 shown in FIG. 2 is a device that displays various information, and includes a display. Note that HMI is an abbreviation for Human Machine Interface.

(External charging control)
Next, an external charging control that charges the high-voltage battery 2 using a power source outside the vehicle will be described. Fig. 3 is a block diagram showing a control configuration of the external charging control. The external charging control is mainly performed by the PCM 201. The PCM 201 corresponds to the "control device" in the claims.

A signal is input to the PCM 201 from the AC charging inlet 42 via the BCCM 205. Specifically, the AC charging inlet 42 is configured to output a predetermined signal (hereinafter, appropriately, referred to as an AC connector engagement signal) to the BCCM 205 when the AC connector is engaged and external charging based on the AC power source 300 outside the vehicle is possible. When the AC connector engagement signal is input from the AC charging inlet 42, the BCCM 205 transmits it to the PCM 201.

A signal is also input to the PCM 201 from the DC charging inlet 52. Specifically, the DC power supply 301 is provided with a specified switch. When the switch is turned ON with the DC connector and the DC charging inlet 52 engaged, the DC power supply 301 outputs power to the high-voltage battery 2. When the switch is turned ON with the DC connector engaged and external charging by the DC power supply 301 is possible, the DC charging inlet 52 transmits a specified signal (hereinafter, appropriately referred to as a DC charging switch ON signal) to the PCM 201.

In addition, detection signals from the battery current sensor SN1 and the battery voltage sensor SN2 are input to the PCM201 via the BECM206.

The PCM 201 performs various calculations and judgments based on the above signals, and issues commands to each device of the vehicle 1. When external charging control is performed, the PCM 201 issues commands at least to the P-side main contactor 71, the N-side main contactor 72, the precharge contactor 73, the OBC contactors 44a and 44b, the QBC contactors 51a and 51b, the DC/DC converter 8, and each controller (DMCM 203, SGCM 204, BCCM 205, BECM 206, ESU 207).

Figure 4 is a flowchart showing the procedure for external charging control. The details of external charging control will be explained using Figure 4. Here, external charging control is performed while the vehicle is stopped, and the flowchart in Figure 4 is performed while the vehicle is stopped. In addition, when the vehicle is stopped, each contactor (main contactors 71, 72, pre-charge contactor 73, OBC contactors 44a, 44b, QBC contactors 51a, 51b) is turned OFF (open state) after a predetermined time, and the flowchart in Figure 4 starts with each contactor in the OFF state.

First, it is determined whether or not an external charging request has been issued (step S1). Then, only when an external charging request has been issued (only when the determination in step S1 is YES) is the processing in step S2 and subsequent steps performed. Specifically, when an AC connector mating signal is sent from the AC charging inlet 42 to the BCCM 205, or a DC charging switch ON signal is sent from the DC charging inlet 52 to the PCM 201, the determination in step S1 becomes YES.

When an AC connector mating signal or a DC charging switch ON signal is transmitted and the determination in step S1 is YES, each controller is started (step S2). That is, power supply from the low-voltage battery 3 to each controller is started. Specifically, when an AC connector mating signal is transmitted to the BCCM 205, the BCCM 205 is first started, and the PCM 201 is started by the BCCM 205. Then, the DMCM 203, the SGCM 204, the BECM 206, and the ESU 207 are started by the PCM 201. Also, when a DC charging switch ON signal is transmitted to the PCM 201, the PCM 201 is started, and the DMCM 203, the SGCM 204, the BCCM 205, the BECM 206, and the ESU 207 are started by the PCM 201. When the AC connector engagement signal is sent to the BCCM 205, the AC connector engagement signal is also sent from the BCCM 205 to the PCM 201, as described above. At this time, power is also supplied from the low-voltage battery 3 to the OBC 41, which is also started up.

Processing from step S2 onwards is performed by PCM201.

First, when the PCM 201 is started in response to an external charging request, it starts the DC/DC converter 8 together with the DMCM 203 (step S3). Specifically, in response to a command from the PCM 201, power supply from the low-voltage battery 3 is started to the DC/DC converter 8 (specifically, the microcomputer provided in the DC/DC converter 8), and the DC/DC converter 8 is made operable. That is, in this embodiment, during external charging, the low-voltage battery 3 is also charged in addition to the high-voltage battery 2, and when an external charging request is issued, the DC/DC converter 8 is made operable and is made capable of stepping down the power it receives and supplying it to the low-voltage battery 3. At the time of step S3, the high-voltage circuit 30 is not electrically connected to either the high-voltage battery 2 or the external charging devices 40 and 50. Therefore, at the time of step S3, the DC/DC converter 8 is not supplied with power, and therefore the DC/DC converter 8 is not in operation.

Next, the PCM 201 determines whether the battery SOC, which is the SOC (State Of Charge) of the high-voltage battery 2, is equal to or greater than a predetermined second judgment SOC (step S4). The PCM 201 calculates the battery SOC based on information related to the high-voltage battery 2 sent from the battery current sensor SN1, the battery voltage sensor SN2, etc. In step S4, the PCM 201 compares this calculated value with the second judgment SOC. The second judgment SOC is preset to a value higher than the first judgment SOC described below and is stored in the PCM 201. The second judgment SOC corresponds to the "second judgment value" in the claims.

If the battery SOC is less than the second judgment SOC and the judgment in step S4 is NO, PCM201 proceeds to step S6. On the other hand, if the battery SOC is equal to or greater than the second judgment SOC and the judgment in step S4 is YES, PCM201 proceeds to step S5 and resets the number of charging failures to 0. After step S5, PCM201 proceeds to step S6. The number of charging failures is the number of times that PCM201 has judged that external charging has failed. The procedure for judging whether external charging has failed will be described later.

In step S6, the PCM 201 determines whether a connection prohibition condition is satisfied, that is, the battery SOC is less than a predetermined first judgment SOC and the number of charging failures is equal to or greater than a predetermined judgment number. The first judgment SOC and the judgment number are set in advance and stored in the PCM 201. In this embodiment, the maximum value of the discharge amount of the high-voltage battery 2 caused by one external charging failure is calculated by experiment or the like, and the number of times that this maximum value can be discharged is set as the judgment number. For example, the judgment number is set to three times. The first judgment SOC is set to 2%, and the second judgment SOC is set to 5%, which is higher than 2%. The first judgment SOC corresponds to the "judgment value" in the claims.

If the above connection prohibition condition is not satisfied and the judgment in step S6 is NO, that is, if the battery SOC is equal to or greater than the first judgment SOC or the number of charging failures has not reached the judgment number, the PCM 201 proceeds to step S7. Then, in step S7, the PCM 201 starts external charging. Specifically, the PCM 201 switches the main contactors 71 and 72 from OFF to ON (closed state) and switches the OBC contactors 44a and 44b or the QBC contactors 51a and 51b from OFF to ON. Also, if an AC connector mating signal has been input, the PCM 201 turns the main contactors 71 and 72 ON, and then outputs a predetermined signal to the AC power supply device 300 to switch the state of the power supply device 300 to a state in which power can be output.

Specifically, when an AC connector mating signal is input, in step S7, the PCM 201 first switches the pre-charge contactor 73, the P-side main contactor 71, and each OBC contactor 44a, 44b to ON, then switches the N-side main contactor 72 to ON and returns the pre-charge contactor 73 to OFF. When the main contactors 71, 72 are turned ON in this manner, the high-voltage battery 2 and the high-voltage circuit 30 are electrically connected. In addition, when the OBC contactors 44a, 44b are turned ON, the high-voltage circuit 30 and the OBC 41 are electrically connected. At the time of step S7, the AC charging inlet 42 and the AC connector are mated, and the AC charging inlet and the OBC 41 are electrically connected to the external AC power source 300. Thus, by carrying out step S7, the AC power source 300 and the high voltage circuit 30 are electrically connected via the AC charging inlet 42 and the OBC 41, the high voltage circuit 30 and the high voltage battery 2 are electrically connected, and the AC power source 300 and the high voltage battery 2 are electrically connected via the AC charging inlet 42, the OBC 41, and the high voltage circuit 30. Here, the control of turning on the OBC contactors 44a and 44b corresponds to "controlling the external charging device so that external charging is started" in the claims.

Also, if a DC charging switch ON signal has been input, in step S7, the PCM 201 first switches the pre-charge contactor 73, the P-side main contactor 71, and each QBC contactor 51a, 51b ON, and then switches the N-side main contactor 72 ON and returns the pre-charge contactor 73 to OFF. As in the above, in this case, the main contactors 71, 72 are turned ON to electrically connect the high-voltage battery 2 and the high-voltage circuit 30. Also, the QBC contactors 51a, 51a are turned ON to electrically connect the high-voltage circuit 30 and the DC charging inlet 52. At the time of step S7, the DC charging inlet 52 and the DC connector are engaged, and the DC charging inlet 52 and the external DC power source 301 are electrically connected. Thus, by carrying out step S7, the DC power supply 301 and the high voltage circuit 30 are electrically connected via the DC charging inlet 52, the high voltage circuit 30 and the high voltage battery 2 are electrically connected, and the DC power supply 301 and the high voltage battery 2 are electrically connected via the DC charging inlet 52 and the high voltage circuit 30. Here, the control of turning on the QBC contactors 51a and 51b corresponds to "controlling the external charging device so that external charging is started" in the claims.

After step S7, the PCM 201 determines whether the battery current on the charging side, which is the current flowing into the high-voltage battery 2, has increased during the time from when step S7 was performed until a predetermined determination time has elapsed (step S8). Specifically, the PCM 201 determines whether the battery current has increased from the value before step S7 was performed, that is, the value before each contactor 71, 72, 44a, 44b (51a, 51b) was switched ON. This determination is performed based on the detection value of the battery current sensor SN1. The above determination time is preset and stored. For example, the determination time is set to about 5 minutes.

If the determination in step S8 is NO, that is, if the battery current on the charging side has not increased during the period from when step S5 was performed until the determination time has elapsed, the PCM 201 proceeds to step S10 and determines that external charging has failed. Then, the number of charging failures is counted up (i.e., 1 is added to the stored number of charging failures).

That is, as described above, by performing step S7, the high-voltage battery 2 and the power source outside the vehicle (AC power source 300 or DC power source 301) are electrically connected. Therefore, if the external charging-related equipment (equipment related to external charging, which is AC power source 300, DC power source 301, AC external charging device 40, and DC external charging device 50) is not broken, power is supplied from the external power sources 300 and 301 to the high-voltage battery 2, and the charging-side current flowing through the high-voltage battery 2 increases. On the other hand, if the external charging-related equipment is broken and external charging is not performed properly, that is, if external charging fails, power is not supplied from the external power sources 300 and 301 to the high-voltage battery 2, and the charging-side current flowing through the high-voltage battery 2 does not increase. Thus, the PCM 201 determines whether external charging has failed based on whether the battery current has increased after performing step S7, as described above.

After step S10, the process proceeds to step S11, where the PCM 201 switches the main contactor from ON to OFF, and switches the OBC contactors 44a, 44b or the QBC contactors 51a, 51b that are ON to OFF, and ends the process (step S11). When step S11 is performed and the contactors 71, 72, 44a, 44b (51a, 51b) are turned OFF, all electrical connections between the high-voltage battery 2, the high-voltage circuit 30, and the power supply device 300 (301) are cut off.

On the other hand, if the determination in step S8 is YES, that is, if the battery current on the charging side has increased between the time when step S5 was performed and the time when the determination time has elapsed, and external charging is being performed properly, the PCM 201 maintains the main contactors 71 and 72 and the OBC contactors 44a and 44b or the QBC contactors 51a and 51b ON and proceeds to step S9. In step S9, the PCM 201 determines whether or not an external charging stop request has been issued. Specifically, the PCM 201 determines that an external charging stop request to stop external charging has been issued when the input of the DC charging switch ON signal is no longer present (the switch of the DC power supply device 301 is turned OFF), when the input of the AC connector engagement signal is no longer present (the AC connector is removed from the AC charging inlet 42), when the high-voltage battery 2 is fully charged, or when a preset external charging time has elapsed.

If an external charging stop request has not been issued and the determination in step S9 is NO, the PCM 201 keeps each contactor 71, 72, 44a, 44b (51a, 51b) ON. Then, if an external charging stop request is issued (the determination in step S9 is YES), the PCM 201 proceeds to step S11, switches the main contactor from ON to OFF, and switches the OBC contactors 44a, 44b or QBC contactors 51a, 51b that are ON to OFF, and ends the process.

Returning to step S6, if the determination in step S6 is YES, that is, if the connection prohibition condition is satisfied, that is, the battery SOC is less than the first determination SOC and the number of charging failures is equal to or greater than the determination number, the PCM 201 proceeds to step S12. In step S12, the PCM 201 maintains the contactors OFF. Specifically, the PCM 201 maintains all of the main contactors 71, 72, the precharge contactor 73, the OBC contactors 44a, 44b, and the QBC contactors 51a, 51b OFF. As a result, all electrical connections between the high-voltage battery 2, the high-voltage circuit 30, and the power supply device 300 (301) are maintained in a disconnected state. After step S12, the PCM 201 proceeds to step S13, where it causes the HMI device 208 to display an abnormality, or the like, to inform the occupant that external charging is not possible, and ends the process.

(effect, etc.)
Fig. 5 to Fig. 7 are time charts showing the change over time of each parameter when the above-mentioned external charging control is performed. Fig. 5 to Fig. 7 illustrate a case where the external charging control is performed in response to an AC connector fitting signal being input to the BCCM 206. Fig. 5 is a time chart when the connection prohibition condition is not satisfied and the AC power supply device 300 is not malfunctioning. Fig. 6 is a time chart when the connection prohibition condition is not satisfied and the AC power supply device 300 is malfunctioning. Fig. 7 is a time chart when the connection prohibition condition is satisfied. 5 to 7 show, from the top, graphs of an external charging request flag, the start-up state of the BCCM 205, the start-up states of the controllers (PCM 201, DMCM 203, SGCM 204, BECM 206, ESU 207) and the DC/DC converter 8, the ON/OFF state of the main contactors 71 and 72, the ON/OFF state of the OBC contactors 44a and 44b, the battery current (current flowing through the high-voltage battery 2), a charging failure flag, and a battery SOC (SOC of the high-voltage battery 2). Note that the graphs of the battery current and battery SOC in FIG. 7 also show the graphs in FIG. 6 by dashed lines. The above-mentioned external charging request flag is a flag that is set to 1 while a request for external charging is being issued and set to 0 otherwise.

In the example of FIG. 5, an external charging request is issued at time t1, and the external charging request flag changes from 0 to 1. FIG. 5 shows an example in which an AC connector fitting signal is input to the BCCM 205. In this case, as described above, at time t2 after time t1, the BCCM 206 is first started and switched from OFF to ON, and then at time t3, the controllers 201, 203, 204, 206, 207 and the DC/DC converter 8 are started and switched from OFF to ON. Also, at time t4 after time t3, the main contactors 71 and 72 and the OBC contactors 44a and 44b are switched from OFF to ON. In addition, in the case of external charging associated with the AC connector fitting signal, as described above, a signal to permit power output is also output from the PCM 201 to the AC power supply device 300.

Figure 8 is a diagram showing the flow of electricity after time t4 in the example of Figure 5. Note that some devices are not shown in Figure 8. When the main contactors 71, 72 and the OBC contactors 44a, 44b are turned ON when the connection prohibition condition is not satisfied and the AC power supply device 300 is not broken, electricity is supplied from the AC power supply device 300 to the AC external charging device 40 as shown by arrow Y1, and electricity is supplied from the AC external charging device 40 to the high voltage circuit 30 as shown by arrow Y2. Then, electricity flows from the high voltage circuit 30 to the high voltage battery 2 as shown by arrow Y3. As a result, in the example of Figure 5, the battery current on the charging side increases after time t4 when the contactors 71, 72, 41a, and 44b are turned ON. The battery SOC also increases after time t4.

Here, the DC/DC converter 8 is started at time t4. As a result, after time t4, as shown by arrow Y4 in FIG. 8, electricity is also supplied from the AC power supply device 300 to the DC/DC converter 8 via the high voltage circuit 30. The output power of the AC power supply device 300 is stepped down by the DC/DC converter 8 and supplied to the low voltage battery 3. Also, as shown by arrow Y6 in FIG. 5, after time t4, the output power of the AC power supply device 300 is also supplied to the PTC heater 9 and the electric compressor 10 via the high voltage circuit 30. Specifically, when a request to operate the PTC heater 9 or the electric compressor 10 is issued, the power required for operation is supplied. On the other hand, when a request to operate is not issued, standby power is supplied to these.

In the example of FIG. 6, when an external charging request is issued at time t1 and the external charging request flag changes from 0 to 1, the BCCM 206 is switched ON at time t2. Also in the example of FIG. 6, since the connection prohibition condition is not satisfied, the controllers 201, 203, 204, 206, 207 and the DC/DC converter 8 are switched ON at time t3, and the main contactors 71, 72 and the OBC contactors 44a, 44b are switched ON at time t4.

However, if the AC power supply device 300 is broken, the flow of electricity after time t4 will be as shown in FIG. 9. In other words, if the AC power supply device 300 is broken, even if the OBC contactors 44a and 44b are turned ON, power is not supplied from the AC power supply device 300 to the AC external charging device 40. Therefore, in this case, when the main contactors 71 and 72 are turned ON and the high-voltage battery 2 and the high-voltage circuit 30 are electrically connected, electricity flows from the high-voltage battery 2 to the high-voltage circuit 30 as shown by the arrow Y11. Then, the output power of the high-voltage battery 2 flowing through the high-voltage circuit 30 is supplied to the low-voltage battery 3 via the DC/DC converter 8 as shown by the arrows Y4 and Y5. Also, the output power of the high-voltage battery 2 is supplied to the PTC heater 9 and the electric compressor 10 as shown by the arrow Y6.

As a result, when the connection prohibition condition is not satisfied and the AC power supply device 300 is faulty, as shown in FIG. 6, after time t4 when the contactors 71, 72, 41a, and 44b are turned ON, the high-voltage battery 2 is discharged, the battery current on the discharge side of the high-voltage battery 2 increases, and the battery SOC decreases. In this case, since there is no increase in the battery current on the charge side between time t4 and time t5, which is the determination time later, the contactors 71, 72, 41a, and 44b are switched OFF at time t5. Also, at time t5, the number of charging failures is counted up. When the contactors 71, 72, 41a, and 44b are switched OFF, the electrical connection between the high-voltage battery 2 and the high-voltage circuit 30 is cut off. As a result, the battery current becomes 0 after time t5, and the decrease in the battery SOC stops at time t5.

7, when an external charging request is issued at time t1 and the external charging request flag changes from 0 to 1, the BCCM 206 is switched ON at time t2. Also, at time t3, the controllers 201, 203, 204, 206, 207 and the DC/DC converter 8 are switched ON. However, in the example of FIG. 7, the connection prohibition condition is met. As a result, in the example of FIG. 7, the main contactors 71, 72 and the OBC contactors 44a, 44b are maintained OFF even after time t3. Therefore, even after time t3, the electrical connection between the high-voltage battery 2 and the high-voltage circuit 30 is maintained in a disconnected state, and the power supply from the high-voltage battery 2 to the low-voltage battery 3 via the DC/DC converter 8 and the power supply from the high-voltage battery 2 to the PTC heater 9 and the electric compressor 10 are continuously stopped. Therefore, in the example of FIG. 7, the battery current is maintained at 0 even after time t3, and a decrease in the battery SOC is avoided. In other words, an increase in the battery current on the discharge side and a decrease in the battery SOC as shown by the dashed line in the example of Figure 6 are avoided.

As described above, in the above embodiment, when an external charging request is issued, unless the connection prohibition condition is satisfied (when the determination in step S6 is NO), the main contactors 71, 72 and the OBC contactors 44a, 44b (QBC contactors 51a, 51b) are switched ON (step S7 is performed), and the external power source 300 (301), the high-voltage circuit 30, and the high-voltage battery 2 are electrically connected. Therefore, while power is supplied from the external power source 300 (301) to the high-voltage battery 2 to charge it, power can also be supplied to the high-voltage device 90 provided in the high-voltage circuit 30.

In particular, in the above embodiment, a DC/DC converter 8 electrically connected to the low-voltage battery 3 is provided in the high-voltage circuit 30, and while the high-voltage battery 2 is being charged, power can also be supplied to the low-voltage battery 3 via the DC/DC converter 8 to charge it. In addition, power can also be supplied to the PTC heater 9 and electric compressor 10 provided in the high-voltage circuit 30, so that the air conditioner can be operated appropriately while the high-voltage battery 2 is being charged.

However, simply electrically connecting the high-voltage battery 2 and the high-voltage circuit 30 in response to a request for external charging will result in power being supplied from the high-voltage battery 2 to the high-voltage circuit 30 and the high-voltage equipment 90 provided therein if the external power supply device 300 (301) fails, as shown in FIG. 9. As a result, the battery SOC will decrease, as shown by the solid line in FIG. 6 and the dashed line in FIG. 7. Note that if the external charging device 40, 50 fails, the high-voltage battery 2 will not be supplied with power from the external power supply 300 (301), so the battery SOC will also decrease.

In contrast, in the above embodiment, when the connection prohibition condition is met, that is, when the battery SOC is less than the first judgment SOC and the number of charging failures is equal to or greater than the judgment number, and there is a high possibility that the external power supply device 300 (301) or the external charging device 40, 50 is malfunctioning (when the judgment in step S6 is NO), the main contactors 71, 72, pre-charge contactor 73, OBC contactors 44a, 44b, and QBC contactors 51a, 51b are all turned OFF, and the electrical connections between the external power supply 300 (301), the high-voltage circuit 30, and the high-voltage battery 2 are maintained in a disconnected state. Therefore, it is possible to reliably prevent the battery SOC from further decreasing from the first judgment SOC and the high-voltage battery 2 from being over-discharged.

In addition, if the battery SOC, i.e., the SOC of the high-voltage battery 2, becomes excessively low, it becomes difficult for the high-voltage battery 2 to charge the low-voltage battery 3, and the SOC of the low-voltage battery 3 also decreases. As described above, each controller operates by receiving power from the low-voltage battery 3. Therefore, if the SOC of the high-voltage battery 2 becomes excessively low, this may lead to a decrease in the SOC of the low-voltage battery 3 and ultimately to the inability to start each controller. In contrast, in the above embodiment, an excessive decrease in the battery SOC is prevented, so that a decrease in the SOC of the low-voltage battery 3 can be prevented and each controller can be prevented from becoming unable to start.

Here, even if external charging has failed in the past, if the battery SOC has recovered and become high, the possibility of the high-voltage battery 2 being over-discharged is small even if the next external charging fails again. In contrast, in the above embodiment, when the battery SOC becomes equal to or higher than the second judgment SOC, which is higher than the first judgment SOC (when the judgment in step S4 is YES), the number of charging failures is reset to 0. As a result, the connection prohibition condition is not satisfied, and the main contactors 71, 72 and the OBC contactors 44a, 44b (QBC contactors 51a, 51b) are turned ON in response to an external charging request, and charging of the high-voltage battery 2 is attempted by the power supply device 300 (301) outside the vehicle. Therefore, it is possible to ensure an opportunity to charge the high-voltage battery 2 by the power supply device 300 (301) outside the vehicle while preventing over-discharging of the high-voltage battery 2.

In addition, in the above embodiment, it is determined that external charging has failed if the current on the charging side of the battery does not increase and power is not supplied from the external power sources 300, 301 to the high-voltage battery 2 even after the judgment time has elapsed since the OBC contactors 44a, 44b (QBC contactors 51a, 51b) were turned ON, that is, since the external charging devices 40, 50 were controlled to start external charging. Therefore, it is possible to determine whether or not external charging has failed with a simple configuration. In particular, if the external power sources 300, 301 are faulty, it is difficult to detect this fault on the vehicle side. In contrast, with this configuration, it is possible to determine that external charging has failed due to a fault in the external power sources 300, 301.

(Modification)
The high-voltage device 90 to which power is supplied from the high-voltage battery 2 is not limited to the above. Furthermore, the specific procedure for determining whether or not external charging has failed is not limited to the above. Furthermore, in the above embodiment, the battery charging device 100 is mounted on a series-type hybrid vehicle, but the type of vehicle on which the battery charging device 100 is mounted is not limited to this.

2 High voltage battery (battery)
3 Low voltage battery 8 DC/DC converter 30 High voltage circuit (electrical equipment circuit)
40 AC external charging device (AC external charging section, external charging device)
50 DC external charging device (DC external charging section, external charging device)
71 P side main contactor (disconnecting device)
72 N-side main contactor (disconnecting device)
90 High voltage equipment (electrical equipment)
201 PCM (control device)
300 External power source, AC power source, AC power supply device 301 External power source, DC power source, DC power supply device

Claims (6)

A battery charging device for a vehicle equipped with a battery and an external charging device capable of performing external charging for charging the battery with power supplied from a power source outside the vehicle,
an electrical device powered by the battery;
a disconnection device capable of connecting and disconnecting an electrical connection between the battery and the electrical device;
A control device for controlling the disconnecting device,
The control device controls the disconnection device so that the electrical connection between the battery and the electrical equipment is cut off when a connection prohibition condition is met, that is, when a request for external charging is issued, the SOC of the battery is less than a predetermined determination value and the number of charging failures, which is the number of times the external charging has failed, is equal to or greater than a predetermined determination number, and when the connection prohibition condition is not met, controls the external charging device so that external charging is started and controls the disconnection device so that the battery and the electrical equipment are electrically connected. 2. The vehicle battery charging device according to claim 1,
The control device determines that the external charging has failed if power is not supplied to the battery from a power source outside the vehicle even after a predetermined determination time has elapsed since the control device controlled the external charging device to start the external charging. 3. The vehicle battery charging device according to claim 1,
the electrical device includes a low-voltage battery having an output voltage lower than that of the battery, and a DC/DC converter that reduces the voltage of the power from the battery and charges the low-voltage battery;
The vehicle battery charging device, wherein the control device starts up the DC/DC converter when a request for external charging is issued. The vehicle battery charging device according to any one of claims 1 to 3,
The vehicle battery charging device comprises an AC external charging unit having an AC/DC converter that converts AC current into DC current and charges the battery with output power from an AC power source outside the vehicle. The vehicle battery charging device according to any one of claims 1 to 4,
2. A vehicle battery charging device, comprising: a DC external charging unit that charges the battery with output power from a DC power source outside the vehicle. The vehicle battery charging device according to any one of claims 1 to 5,
the battery is electrically connected to the external charging device via an electric equipment circuit in which the electric equipment is provided;
the disconnecting device disconnects an electrical connection between the battery and the electrical device by connecting or disconnecting an electrical connection between the electrical device circuit and the battery;
The vehicle battery charging device is characterized in that, when the number of charging failures is 1 or more, the control device resets the number of charging failures to 0 when the SOC of the battery becomes equal to or greater than a predetermined second determination value that is higher than the determination value.