JP7760422B2 - Vehicle Power System - Google Patents

Description

The present invention relates to a vehicle power supply system that supplies power to on-board devices in a vehicle.

Patent Document 1 discloses the configuration of a charging port for an electric vehicle that uses a simple method to ground the cable. Patent Document 2 describes a charging cable for an electric vehicle that is composed of a current supply line, a ground line, and a shielded wire, in which the ground line and shielded wire are grounded on the charger side and short-circuited on the electric vehicle side to reduce radiated noise. Patent Document 3 also describes a charging device that includes a vehicle body connection wire in the charging cable and detects a ground fault from the potential of the vehicle body connection wire.

JP 2010-166756 A Patent No. 5048888 Japanese Patent Application Publication No. 5-276674

When charging a secondary battery for powering an electric vehicle using high-capacity charging equipment at a charging station or the like, electromagnetic noise caused by a large charging current flowing through the secondary battery for powering the vehicle can disrupt viewing on in-vehicle AV equipment.
An object of the present invention is to reduce the influence of electromagnetic noise on in-vehicle AV equipment when an electric vehicle is being charged.

One aspect of the present invention is a vehicle power supply system having a first battery that supplies power to a rotating electric machine of a vehicle, a second battery that supplies power to AV equipment mounted on the vehicle, a switching device that electrically disconnects a second ground line of the AV equipment and the second battery from a first ground line of the first battery when the vehicle is in an external charging state in which the first battery is being charged from outside the vehicle, and a shielding structure that electromagnetically shields one of a first load circuit including the rotating electric machine connected to the first battery and a second load circuit including the AV equipment connected to the second battery from the other load circuit.
According to another aspect of the present invention, the switching device disconnects the electrical connection between the first ground line, which is grounded to the earth via the body of the vehicle, and the second ground line.
According to another aspect of the present invention, the vehicle includes a battery socket for removably attaching at least one of the first battery and the second battery to the body of the vehicle, and the switching device disconnects the electrical connection between the first ground line and the second ground line by disconnecting the electrical connection between the ground line of the first battery and the ground line of the second battery at the battery socket.
According to another aspect of the present invention, at least when the second ground line is electrically disconnected from the first ground line by the switching device, the AV equipment communicates with other equipment installed in the vehicle using a carrier that allows communication even when electrically isolated.

This invention reduces the impact of electromagnetic noise on in-vehicle AV equipment when charging an electric vehicle.

1 is a diagram showing a configuration of a vehicle power supply system according to a first embodiment of the present invention; FIG. 10 is a diagram showing the configuration of a vehicle power supply system according to a second embodiment of the present invention. FIG. 10 is a diagram showing the configuration of a vehicle power supply system according to a third embodiment of the present invention. FIG. 10 is a diagram showing the configuration of a vehicle power supply system according to a fourth embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[First embodiment]
1 is a diagram showing the configuration of a vehicle power supply system 2a mounted on a vehicle 1, which is an electric vehicle, according to a first embodiment of the present invention. The vehicle power supply system 2a includes a rotating electric machine 3 that drives the vehicle 1, AV equipment 4, a first battery 5 that supplies power to the rotating electric machine 3, a second battery 6 that supplies power to the AV equipment 4, an ECU 7 that controls various functions of the vehicle 1, and a switching control device 8a. The AV equipment 4 may be, for example, a television, a communication device such as a TCU (Telematics Control Unit), a display audio, a radio device, an IVI (In-Vehicle Infotainment) device, or the like.

The first battery 5 is charged by the rotating electric machine 3 when the rotating electric machine 3 operates in generator mode due to so-called regenerative braking, and is also charged by receiving power from a charging facility external to the vehicle 1 via a charging connector 9 provided on the vehicle body. The rotating electric machine 3 is equipped with a drive device (not shown) that controls whether to generate driving force or supply power generated by regenerative braking to the first battery 5.

A first ground line 10 (one of the thick lines in the figure) is connected between the rotating electric machine 3 and the first battery 5, and a second ground line 11 (the other thick line in the figure) is connected between the AV equipment 4 and the second battery 6. The ground of the ECU 7 is also connected to the first ground line 10.

In this embodiment, the first ground line 10 is grounded to the earth via the vehicle body ground 12, which is a ground line formed by the body of the vehicle 1, and the second ground line 11 is connected to the first ground line 10 via a switching device 30a. The switching device 30a is, for example, a normally-on type relay, and when the switching device 30a is not energized, the first ground line 10 and the second ground line 11 are connected. Hereinafter, the switching device 30a, as well as the switching devices 30b, 30c, 30d, and 30e described below, will be collectively referred to as the switching device 30.

In each embodiment described herein, the switching device 30 is a relay controlled by a switching control device 8a, 8b, or 8c, which will be described later, but is not limited to this. As will be described later, the switching device 30 may be any electrical component, such as a mechanical switch, that can connect/disconnect the first ground line 10 and the second ground line 11.

When the vehicle 1 is in an external charging state in which the first battery 5 is being charged from outside the vehicle 1, the switching control device 8a controls the switching device 30 to electrically disconnect the second ground line between the AV equipment 4 and the second battery 6 from the first ground line 10 of the first battery 5.

The switching control device 8a includes a processor 20a and a memory 21. The memory 21 is, for example, composed of volatile and/or non-volatile semiconductor memory and/or a hard disk drive. The processor 20a is, for example, a computer equipped with a CPU (Central Processing Unit). The processor 20a may also include a ROM (Read Only Memory) in which a program is written, a RAM (Random Access Memory) for temporary data storage, and the like. The processor 20a also includes, as functional elements or units, a detection unit 22 and a switching control unit 23a.

These functional elements of processor 20a are realized, for example, by processor 20a, which is a computer, executing a program. The computer program can be stored on any computer-readable storage medium. Alternatively, all or part of the functional elements of processor 20a can be configured as hardware, each including one or more electronic circuit components.

The detection unit 22 detects power supply to the first battery 5 from outside the vehicle 1 and detects that the vehicle 1 is in an external charging state in which the first battery 5 is being charged from outside the vehicle. For example, the detection unit 22 detects that the vehicle 1 is in an external charging state using a power supply sensor 13 provided between the first battery 5 and the charging connector 9. The power supply sensor 13 may be, for example, a current sensor that detects the current in the conductive cable between the first battery 5 and the charging connector 9. Alternatively, the power supply sensor 13 may be a mechanical sensor that detects that an external charging cable has been connected to the charging connector 9.

The switching control unit 23a electrically disconnects the second ground line 11 from the first ground line 10 when the vehicle 1 is in an external charging state. In this embodiment, the switching control unit 23a, for example, instructs the switching device 30a, which turns the connection between the second ground line 11 and the first ground line 10 on and off, thereby electrically disconnecting the connection between the second ground line 11 and the first ground line 10 when the vehicle 1 is in an external charging state.

The vehicle power supply system 2a also includes a shielding structure 14 that electromagnetically shields the second load circuit 24b, which includes the AV equipment 4 connected to the second battery 6, from the first load circuit 24a, which includes the rotating electric machine 3 connected to the first battery 5. The shielding structure 14 does not need to be a sealed enclosure, and can be made of a conductive material with mesh, slits, and/or openings sized according to the wavelength of the electromagnetic waves to be shielded, in accordance with conventional technology.

In the vehicle power supply system 2a configured as described above, when the vehicle 1 is in an external charging state, the second ground line 11 and the first ground line 10 are electrically disconnected, and the shielding structure 14 electromagnetically shields the second load circuit 24b, including the AV equipment 4, from the first load circuit 24a, including the rotating electric machine 3. Therefore, in the vehicle power supply system 2a, when the first battery 5 of the vehicle 1 is being charged by high-capacity charging equipment at a charging station or the like, the impact of electromagnetic noise on the AV equipment 4 caused by the large charging current flowing through the first battery 5 for power can be effectively reduced. This reduces viewing disruptions on the AV equipment 4 when the vehicle 1 is in the external charging state.

Note that when the second ground line 11 is electrically disconnected from the first ground line 10, the ground potentials of the AV equipment 4 and the ECU 7 may differ, which may interfere with electrical communication between them. For this reason, the AV equipment 4 and the ECU 7 may communicate using a carrier that allows communication even when electrically isolated, such as light, sound, or vibration, which can maintain electrical isolation between the AV equipment 4 and the ECU 7. In this embodiment, communication between the AV equipment 4 and the ECU 7 is performed using light as a carrier, for example, via a photocoupler 15. Note that such communication using a carrier that can maintain electrical isolation does not need to be performed constantly between the AV equipment 4 and the ECU 7; it may be performed at least when the vehicle 1 is in an external charging state.

Second Embodiment
Fig. 2 is a diagram showing the configuration of a vehicle power supply system 2b according to a second embodiment of the present invention. In Fig. 2, the same components as those shown in Fig. 1 are designated by the same reference numerals as those shown in Fig. 1, and the description of Fig. 1 above is incorporated herein.

Vehicle power supply system 2b has a similar configuration to vehicle power supply system 2a, but the first ground line 10 and second ground line 11 are connected to the vehicle ground 12 via switching devices 30b and 30c, respectively. Switching devices 30b and 30c are, for example, normally-on relays, similar to switching device 30a. When switching devices 30b and 30c are not energized, the first ground line 10 and second ground line 11 are both connected to the vehicle ground 12.

Vehicle power supply system 2b also differs from vehicle power supply system 2a in that it has switching control device 8b instead of switching control device 8a. Switching control device 8b has a similar configuration to switching control device 8a, but differs in that it has processor 20b including switching control unit 23b instead of processor 20a including switching control unit 23a. Switching control unit 23b has a similar configuration to switching control unit 23a, but differs in that when vehicle 1 is in an external charging state, switching control unit 23b electrically disconnects second ground line 11 from first ground line 10 by operating either switching device 30b arranged between first ground line 10 and vehicle body ground 12 or switching device 30c arranged between second ground line 11 and vehicle body ground 12.

In the vehicle power supply system 2b, for example, when the vehicle 1 is in an external charging state, the switching device 30c is operated to set the connection off state, electrically disconnecting the second ground line 11 from the vehicle body ground 12 to which the first ground line 10 is connected. This effectively reduces the impact on the AV equipment 4 of electromagnetic noise caused by the charging current flowing through the first battery 5, as in the first embodiment shown in Figure 1.

In addition, in the vehicle power supply system 2b, for example, if a charging cable from an external charging facility is connected to the charging connector 9, and the first ground line 10 is connected to a ground line outside the vehicle via the charging connector 9 and the charging cable, the switching device 30b may be operated to turn the connection off when the vehicle 1 is in an external charging state. This ensures that the first ground line 10 is grounded by the ground line outside the vehicle when the first battery 5 is being charged, while maintaining the second ground line 11 grounded to the vehicle body ground 12, thereby reducing the effects of electromagnetic noise on the AV equipment 4.

[Third embodiment]
Fig. 3 is a diagram showing the configuration of a vehicle power supply system 2c according to a third embodiment of the present invention. In Fig. 3, the same components as those shown in Fig. 1 are designated by the same reference numerals as those shown in Fig. 1, and the description of Fig. 1 above is used.

Vehicle power supply system 2c has a similar configuration to vehicle power supply system 2a, but the first ground line 10 and the second ground line 11 are connected via switching device 30a, and the output line 16 of the first battery 5 and the output line 17 of the second battery 6 are connected via switching device 30d. Switching device 30d is, for example, a normally-on type relay, similar to switching device 30a.

Vehicle power supply system 2c also differs from vehicle power supply system 2a in that it has switching control device 8c instead of switching control device 8a. Switching control device 8c has the same configuration as switching control device 8a, but differs in that it has processor 20c including switching control device 23c instead of processor 20a including switching control unit 23a. Unlike switching control device 23a, switching control device 23c sets both switching devices 30a and 30d to the connection-on state when vehicle 1 is not in an external charging state, and operates both switching devices 30a and 30d to the connection-off state when vehicle 1 is in an external charging state.

As a result, in the vehicle power supply system 2c, when the vehicle 1 is not in an external charging state, the output line 16 and first ground line 10 of the first battery 5 are connected to the output line 17 and second ground line 11 of the second battery 6, respectively, and both the first battery 5 and the second battery 6 can be charged by the rotating electric machine 3 during regenerative braking or other operations while the vehicle 1 is running. On the other hand, when the vehicle 1 is in an external charging state, the vehicle power supply system 2c electrically disconnects the output line 16 and first ground line 10 of the first battery 5 from the output line 17 and second ground line 11 of the second battery 6, respectively. This effectively reduces the impact of electromagnetic noise caused by the charging current flowing through the first battery 5 on the AV equipment 4, similar to the first embodiment shown in FIG. 1 .

[Fourth embodiment]
Fig. 4 is a diagram showing the configuration of a vehicle power supply system 2d according to a fourth embodiment of the present invention. In Fig. 4, the same components as those shown in Fig. 1 are designated by the same reference numerals as those shown in Fig. 1, and the description of Fig. 1 above is incorporated herein.

Vehicle power supply system 2d has a similar configuration to vehicle power supply system 2a, but the first battery 5 and second battery 6 are detachably fixed to vehicle 1 via battery sockets 18 and 19, respectively. This allows vehicle power supply system 2d to use, for example, portable mobile batteries as the first battery 5 and second battery 6.

In the vehicle power supply system 2d, the first ground line 10 and the second ground line 11 are connected by a switching device 30e, which connects the internal ground lines of the battery sockets 18 and 19 to each other. The switching device 30e is, for example, a normally-on type relay, similar to the switching device 30a.

Instead of battery sockets 18 and 19, a single battery socket with two slots into which the first battery 5 and second battery 6 can be inserted can also be used. In this case, the switching device 30e can be built into the battery socket.

The switching control unit 23a of the switching control device 8a sets the switching device 30e to the connection-on state when the vehicle 1 is not in an external charging state, and operates the switching device 30e to the connection-off state when the vehicle 1 is in an external charging state. In other words, the switching control unit 23a turns the electrical connection between the ground line of the first battery 5 in the battery socket 18 and the ground line of the second battery 6 in the battery socket 19 on and off using the switching device 30e, thereby turning the electrical connection between the first ground line 10 and the second ground line 11 on and off.

As a result, in the vehicle power supply system 2d, similar to the first embodiment shown in FIG. 1, when the vehicle 1 is not in an external charging state, the impact of electromagnetic noise caused by the charging current flowing through the first battery 5 on the AV equipment 4 can be effectively reduced. Furthermore, in the vehicle power supply system 2d, the switching device 30e connects the internal ground lines of the two battery sockets 18, 19, thereby simplifying the configuration of the wire harness routed within the vehicle 1 to connect the battery sockets 18, 19 to the on-board devices. Furthermore, because the respective ground lines are connected in close proximity to the first battery 5 and the second battery 6, electromagnetic noise is less likely to occur.

Other Embodiments
In the above-described embodiments, the shielding structure 14 electromagnetically shields the second load circuit 24b including the AV equipment 4 connected to the second battery 6 from the first load circuit 24a including the rotating electric machine 3 connected to the first battery 5, but the reverse may also be true. That is, the vehicle power supply systems 2a, 2b, 2c, and 2d (hereinafter also collectively referred to as the vehicle power supply system 2) may include a shielding structure that electromagnetically shields one of the first load circuit 24a and the second load circuit 24b from the other load circuit.

In the vehicle power supply system 2 shown in each of the above-described embodiments, the switching device 30 is a relay controlled by the switching control devices 8a, 8b, and 8c (hereinafter collectively referred to as the switching control device 8), but is not limited to this. The switching device 30 may be any electrical component, such as a mechanical switch, that can connect and disconnect the first ground line 10 and the second ground line 11.

For example, the switching device 30 may be a mechanical switch provided in the charging connector 9, which breaks the electrical contact when the plug of the charging cable is connected to the charging connector 9 and makes the electrical contact when the plug is removed from the charging connector 9.

The present invention is not limited to the configuration of the above embodiment, and can be implemented in various forms without departing from the spirit of the invention.

[Configuration supported by the above embodiment]
The above-described embodiment supports the following configurations.

(Configuration 1) A vehicle power supply system having a first battery that supplies power to a rotating electric machine of a vehicle, a second battery that supplies power to AV equipment mounted on the vehicle, a switching device that electrically disconnects a second ground line of the AV equipment and the second battery from a first ground line of the first battery when the vehicle is in an external charging state in which the first battery is being charged from outside the vehicle, and a shielding structure that electromagnetically shields one of a first load circuit including the rotating electric machine connected to the first battery and a second load circuit including the AV equipment connected to the second battery from the other load circuit.
The vehicle power supply system of configuration 1 can effectively reduce the influence on AV equipment of electromagnetic noise caused by a large charging current flowing through the first battery, thereby reducing disturbances to viewing on the AV equipment.

(Configuration 2) A vehicle power supply system as described in Configuration 1, wherein the switching device disconnects the electrical connection between the first ground line, which is grounded to the ground via the vehicle body, and the second ground line.
According to the vehicle power supply system of configuration 2, it is possible to ensure grounding when charging the first battery, while reducing disturbances to viewing on AV equipment.

(Configuration 3) A vehicle power supply system as described in Configuration 1, comprising a battery socket for removably attaching at least one of the first battery and the second battery to the vehicle body, and the switching device disconnects the electrical connection between the first ground line and the second ground line by disconnecting the electrical connection between the ground line of the first battery and the ground line of the second battery in the battery socket.
According to the vehicle power supply system of configuration 3, the configuration of the wire harness inside the vehicle can be simplified and electromagnetic noise from the first battery can be reduced.

(Configuration 4) A vehicle power supply system described in any of configurations 1 to 3, wherein the AV equipment communicates with other equipment installed in the vehicle using a carrier that allows communication even when electrically isolated, at least when the second ground line is electrically disconnected from the first ground line by the switching device.
According to the vehicle power supply system of configuration 4, even if the second ground line is disconnected from the first ground line, good communication can be achieved between the AV device and other in-vehicle devices.

1...vehicle, 2, 2a, 2b, 2c, 2d...vehicle power supply system, 3...rotating electric machine, 4...AV equipment, 5...first battery, 6...second battery, 7...ECU, 8, 8a, 8b, 8c...switching control device, 9...charging connector, 10...first ground line, 11...second ground line, 12...vehicle body ground, 13...power supply sensor, 14...shield structure, 15...photocoupler, 16, 17...output line, 18, 19...battery socket, 20a, 20b, 20c...processor, 21...memory, 22...detection unit, 23a, 23b, 23c...switching control unit, 24a...first load circuit, 24b...second load circuit, 30, 30a, 30b, 30c, 30d, 30e...switching device.

Claims (4)

a first battery that supplies power to a rotating electric machine of the vehicle;
a second battery for supplying power to AV equipment mounted on the vehicle;
a switching device that electrically disconnects a second ground line of the AV equipment and the second battery from a first ground line of the first battery when the vehicle is in an external charging state in which the first battery is charged from outside the vehicle;
a shielding structure that electromagnetically shields one of a first load circuit including the rotating electric machine connected to the first battery and a second load circuit including the AV equipment connected to the second battery from the other load circuit;
having
Vehicle power system. the switching device disconnects the electrical connection between the first ground line, which is grounded to the ground via a body of the vehicle, and the second ground line;
10. The vehicle power supply system of claim 1. a battery socket for detachably mounting at least one of the first battery and the second battery to a body of the vehicle;
the switching device electrically disconnects the ground line of the first battery from the ground line of the second battery in the battery socket, thereby electrically disconnecting the first ground line from the second ground line.
10. The vehicle power supply system of claim 1. At least when the second ground line is electrically disconnected from the first ground line by the switching device, the AV device communicates with other devices mounted on the vehicle using a carrier that allows communication even in an electrically isolated state.
4. The vehicle power supply system according to claim 1.