Vehicle battery system

Abstract

A vehicle-mounted battery system has a battery; a relay for turning on or off a connection between the battery and an inverter; a plurality of switches respectively provided on current paths for switching the relay; and a battery control device for monitoring a state of the battery, the plurality of switches including a first switch provided in the battery control device and a second switch provided in a vehicle control device for performing travel control of a vehicle, the first switch and the second switch being connected in series with each other on the current paths, the battery control device controlling a switching state of the first switch, and the vehicle control device controlling a switching state of the second switch.

Description

Technical Field

[0001] This invention relates to an on-board battery system. Background Technology

[0002] Battery modules are known to be constructed by connecting multiple secondary battery cells (single cells) such as lithium-ion batteries in series or in parallel to form battery packs, and further by connecting multiple battery packs in series or in parallel to form battery modules. Typically, in electric vehicles or hybrid electric vehicles, batteries (high-voltage batteries) consisting of multiple such battery modules connected in series or in parallel, along with a battery control device that controls each battery module, are used as energy storage devices. A converter converts the high-voltage DC power supplied from the energy storage device into AC power, which is then used to drive the motor, thus propelling the electric vehicle. Additionally, a converter converts the AC power generated by the motor's regenerative braking into DC power and supplies this DC power to the energy storage device, thereby charging the energy storage device.

[0003] In electric vehicles equipped with the aforementioned energy storage devices, high-voltage relays are typically provided on both the positive and negative sides of the battery and between the battery and the converter, respectively, for connecting or disconnecting the connection between the battery and the converter. Furthermore, sometimes a pre-charge relay, connected in parallel with one of the relays on the positive or negative side and connected in series with a current-limiting resistor, is also provided. In electric vehicles equipped with a pre-charge relay, the pre-charge relay is first activated during system startup to limit the inrush current, and then the high-voltage relay is activated to deactivate the pre-charge relay.

[0004] Typically, to ensure the safe use of lithium-ion batteries, electric vehicles equipped with energy storage devices using lithium-ion batteries are equipped with systems to prevent overcharging and over-discharging of the batteries. Furthermore, in recent years, due to increasing demands for vehicle functional safety, the application of functional safety standards such as ISO 26262 has developed. In this context, in electric vehicles equipped with energy storage devices using lithium-ion batteries, it is necessary to reliably disconnect the connection between the battery and the converter to ensure safety in the event of an electronic circuit failure.

[0005] As prior art related to this technical field, Patent Document 1 is known. In Patent Document 1, a relay control circuit is disclosed that connects the relay to continue supplying power from the high-voltage battery only when both the output signal of the vehicle control device and the output signal of the battery control device are signals indicating that the power supply should continue.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2013-240165 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] In the relay control circuit described in Patent Document 1, an AND circuit, which is the logical product of the output signal from the vehicle control device and the output signal from the battery control device, is connected to two relays respectively. The output signals from these AND circuits are used to control the on / off state of each relay. Therefore, if one of the AND circuits fails, the relay switching may be impossible. Especially in energy storage devices using lithium-ion batteries, if the relay remains on, the battery may sometimes be overcharged or over-discharged, thus making it difficult to switch the relay from on to off. Therefore, in the prior art, if a fault occurs in the circuit controlling the relay that connects or disconnects the battery from the converter, there is a risk of the battery being overcharged or over-discharged.

[0011] Technical means to solve the problem

[0012] The vehicle battery system of the present invention is a battery system connected to an inverter mounted on a vehicle and transmitting and receiving direct current between the battery system and the inverter. The battery system includes: a battery; a relay for connecting or disconnecting the connection between the battery and the inverter; a plurality of switches respectively disposed on a current path for switching the relay; and a battery control device for monitoring the state of the battery. The plurality of switches include: a first switch disposed within the battery control device; and a second switch disposed within a vehicle control device for controlling the driving of the vehicle. The first switch and the second switch are connected in series in the current path. The battery control device controls the switching state of the first switch, and the vehicle control device controls the switching state of the second switch.

[0013] The effects of the invention

[0014] According to the present invention, even if one of the battery control device and the vehicle control device, which are controlled by relays that connect or disconnect the battery and the converter respectively, fails, overcharging and over-discharging of the battery can be reliably prevented. Attached Figure Description

[0015] Figure 1 This is a diagram showing the configuration of the battery system according to the first embodiment of the present invention.

[0016] Figure 2 This is a diagram illustrating an example of the internal circuitry of a battery control device.

[0017] Figure 3This is a flowchart illustrating the sequence of actions performed when the battery control device is started normally.

[0018] Figure 4 This is a flowchart illustrating the sequence of actions taken when an anomaly is detected during the startup of the battery control device.

[0019] Figure 5 This is a flowchart illustrating the sequence of actions taken when an anomaly is detected after the battery control device has started normally.

[0020] Figure 6 This is a diagram showing the configuration of the battery system according to the second embodiment of the present invention. Detailed Implementation

[0021] Hereinafter, embodiments of the present invention will be described using the accompanying drawings.

[0022] (First Embodiment)

[0023] Figure 1 This is a diagram showing the configuration of the battery system according to the first embodiment of the present invention. Figure 1 The battery system shown is connected to a converter 1 mounted on the vehicle, and performs DC power transfer between the battery system and the converter 1. It includes a high-voltage relay 2, a battery 3, a vehicle control unit 4, and a battery control unit 5. The vehicle control unit 4 and the battery control unit 5 are interconnected via a CAN (Controller Area Network) communication line 15 located within the vehicle.

[0024] The converter 1 performs mutual conversion between DC power and AC power between a motor (not shown) and a battery 3 installed in the vehicle. That is, the DC power supplied from the battery 3 is converted into AC power by the converter 1 and output to the motor. Conversely, the AC power supplied from the motor is converted into DC power by the converter 1 and output to the battery 3.

[0025] A high-voltage relay 2 is connected between the converter 1 and the battery 3, and includes a positive-side relay 201, a negative-side relay 203, a pre-charge relay 202, and a pre-charge resistor 204. The positive-side relay 201 is connected between the positive wiring 20 of the converter 1 and the positive wiring 22 of the battery 3. The negative-side relay 203 is connected between the negative wiring 21 of the converter 1 and the negative wiring 23 of the battery 3. The pre-charge relay 202 is connected in parallel with the negative-side relay 203 between the negative wiring 21 of the converter 1 and the negative wiring 23 of the battery 3. The pre-charge resistor 204 is connected in series with the pre-charge relay 202.

[0026] Each of the positive-side relay 201, pre-charge relay 202, and negative-side relay 203 has a built-in excitation coil for switching these relays. The excitation coil of the positive-side relay 201 is connected to current paths 12 and 16. The excitation coil of the pre-charge relay 202 is connected to current paths 13 and 17. The excitation coil of the negative-side relay 203 is connected to current paths 14 and 17. When current flows through these excitation coils in their respective current paths, a magnetic field is generated by the current, thereby switching the corresponding relays to the ON state. Conversely, when no current flows through any current path, the corresponding relays are switched to the OFF state. Thus, the relays are switched based on the presence or absence of current flowing through each current path.

[0027] The battery 3, which is a high-voltage battery, is constructed by connecting multiple individual cells 301 in series and parallel. Each individual cell 301 is constructed using a secondary battery such as a lithium-ion battery.

[0028] The vehicle control unit 4 connects to various sensors and actuators (not shown) mounted on the vehicle, using them for vehicle driving control. Additionally, the vehicle control unit 4 internally includes a relay control switch 401. The relay control switch 401 consists of three switches 401-1, 401-2, and 401-3, respectively connected to the positive-side relay 201, pre-charge relay 202, and negative-side relay 203 of the high-voltage relay 2. One end of switch 401-1 is connected to the excitation coil of the positive-side relay 201 via current path 12. One end of switch 401-2 is connected to the excitation coil of the pre-charge relay 202 via current path 13. One end of switch 401-3 is connected to the excitation coil of the negative-side relay 203 via current path 14. The other ends of these switches are all connected to a low-voltage power supply 11 within the vehicle. This low-voltage power supply 11 is, for example, a 12V electrical system power supply. The switching state of each switch in the relay control switch 401 is controlled by the vehicle control unit 4.

[0029] The battery control device 5 is connected to the connection points between each individual cell 301 of the battery 3 via voltage detection line 19, detecting the voltage of each individual cell 301 and monitoring the state of the battery 3. Additionally, the battery control device 5 internally includes a relay control switch 501. The relay control switch 501 consists of switch 501-1 connected to the positive side relay 201 of the high-voltage relay 2 and switch 501-2 connected to the pre-charge relay 202 and the negative side relay 203. One end of switch 501-1 is connected to the excitation coil of the positive side relay 201 via current path 16. One end of switch 501-2 is connected to the excitation coils of the pre-charge relay 202 and the negative side relay 203 via current path 17. The other ends of these switches are connected to the chassis GND18, which serves as the GND of the low-voltage power supply 11. The switching state of switches 501-1 and 501-2 is controlled by the battery control device 5, and they are always switched to the ON state when the battery control device 5 is operating normally.

[0030] As described above, in the battery system of this embodiment, the three switches 401-1, 401-2, and 401-3 of the relay control switch 401 are arranged on the side closer to the low-voltage power supply 11, i.e., the high-potential side, in the current paths 12 to 14, compared to the excitation coils of each relay in the high-voltage relay 2. On the other hand, switches 501-1 and 501-2 of the relay control switch 501 in the battery control device 5 are arranged on the side closer to the chassis GND18, i.e., the low-potential side, in the current paths 16 and 17, compared to the excitation coils of each relay in the high-voltage relay 2. Therefore, by switching these switches to the ON state, current can flow through the excitation coils via each current path, switching each relay of the high-voltage relay 2 to the ON state.

[0031] when Figure 1When the battery system starts and the battery control device 5 begins to operate, switches 501-1 and 501-2 in relay control switch 501 are switched to the ON state. Additionally, switches 401-1 and 401-2 in relay control switch 401 are switched to the ON state via vehicle control device 4. As a result, current flows through current paths 12 and 16, switching the positive-side relay 201 to the ON state, and current flows through current paths 13 and 17, switching the pre-charge relay 202 to the ON state. Consequently, with the inrush current reduced by the pre-charge resistor 204, the converter 1 is connected to the battery 3. Afterwards, when the smoothing capacitor in the converter 1 is charged to a voltage above a certain level, switch 401-3 is switched to the ON state, and switch 401-2 is switched to the OFF state. As a result, current flows through current paths 14 and 17, switching the negative-side relay 203 to the ON state, and the current in current path 13 is cut off, switching the pre-charge relay 202 to the OFF state. As a result, the connection between converter 1 and battery 3 ends, and DC power is transferred between converter 1 and battery 3.

[0032] In addition, Figure 1 In the example of the battery system shown, the pre-charge relay 202 and the pre-charge resistor 204 are connected in parallel with the negative-side relay 203 between the negative-side wiring 21 of the converter 1 and the negative-side wiring 23 of the battery 3. However, the pre-charge relay 202 and the pre-charge resistor 204 can also be connected in parallel with the positive-side relay 201 between the positive-side wiring 20 of the converter 1 and the positive-side wiring 22 of the battery 3. Alternatively, the pre-charge relay 202 and the pre-charge resistor 204 may not be provided if inrush current is not a problem.

[0033] Here, it is assumed that after the connection between converter 1 and battery 3 is completed, an abnormality occurs in battery 3 and battery control device 5. In this case, vehicle control device 4 switches each switch of relay control switch 401 to the open state. In addition, battery control device 5 switches switches 501-1 and 501-2 of relay control switch 501 to the open state. As a result, the current flowing through current paths 12 and 16 is cut off, positive side relay 201 is switched to the open state, and the current flowing through current paths 14 and 17 is cut off, negative side relay 203 is switched to the open state. Thus, in the battery system of this embodiment, the system for disconnecting the connection between converter 1 and battery 3 is set as a dual system through the system of relay control switch 401 in vehicle control device 4 and the system of relay control switch 501 in battery control device 5. Therefore, even if a fault occurs in either system, overcharging and over-discharging of battery 3 can be reliably prevented.

[0034] Figure 2 This diagram illustrates an example of the internal circuitry of the battery control device 5. The battery control device 5 has the following components: Figure 1 The relay control switch 501 shown includes switches 501-1 and 501-2, and has terminals denoted by symbols 502 to 507 and 520, a power supply circuit 508, a monitoring circuit 510, monitoring circuits 514-1 and 514-2, a drive circuit 516, a microcomputer 518, and a CAN driver 519.

[0035] Terminal 502 is used to input the operating power supply of the battery control device 5. The operating power supply input from terminal 502 is voltage-converted by the power supply circuit 508, as shown by symbol 509, and output to the microcomputer 518 as the power supply VCC.

[0036] Terminals 503 and 504 are respectively with Figure 1 Current paths 16 and 17 are connected. Switches 501-1 and 501-2 are respectively connected to terminals 503 and 504 and current paths 16 and 17. Figure 1 The excitation coils of the positive side relay 201, the pre-charge relay 202, and the negative side relay 203 are connected.

[0037] Terminals 505, 506, and 507 are all connected to chassis GND 18. Switches 501-1 and 501-2 are connected to chassis GND 18 via terminals 505 and 506, respectively. Microcomputer 518 is connected to chassis GND 18 via terminal 507.

[0038] Thus, in the battery control device 5, multiple terminals (terminals 503 and 504) are provided for connecting to the excitation coils of each relay, and terminals (terminals 505, 506, and 507) are provided for connecting to the chassis GND18. The reason for this is to employ a configuration with a margin to ensure that the allowable current of each terminal is not exceeded. Furthermore, considering that a large increase in terminal current would cause a voltage drop due to contact resistance, which would adversely affect circuit operation, this configuration also aims to prevent such adverse effects.

[0039] The monitoring circuit 510 monitors the operation of the microcomputer 518 by inputting and outputting prescribed data between itself and the microcomputer 518 via signal line 512. For example, it monitors whether the microcomputer 518 is malfunctioning, or if the microcomputer is a dual-core computer, whether there is inconsistency in the operations between the two cores. In the event of such malfunctions, the monitoring circuit 510 outputs a reset signal 511 to reset the microcomputer 518, or outputs a microcomputer fail signal 513 to the drive circuit 516.

[0040] Monitoring circuits 514-1 and 514-2 monitor the status of switches 501-1 and 501-2 respectively, and output the results to microcomputer 518.

[0041] The drive circuit 516 switches switches 501-1 and 501-2 to an ON or OFF state, respectively, based on the drive signal 517 output from the microcomputer 518 or the microcomputer Fail signal 513 output from the monitoring circuit 510. Specifically, when the drive signal 517 is output from the microcomputer 518, the drive circuit 516 switches switches 501-1 and 501-2 to an ON state. Conversely, when the microcomputer Fail signal 513 is output from the monitoring circuit 510, regardless of the presence or absence of the drive signal 517, the drive circuit 516 switches switches 501-1 and 501-2 to an OFF state. Therefore, in the event of an malfunction in the microcomputer 518, [the circuit will...]. Figure 1 The positive side relay 201 and the negative side relay 203 are switched to the off state, cutting off the connection between the converter 1 and the battery 3.

[0042] Terminal 520 and Figure 1 The CAN communication line 15 shown is connected. The CAN driver 519 converts the data output from the microcomputer 518 into CAN signals and sends them to the CAN communication line 15 via terminal 520. It also converts the CAN signals received from the CAN communication line 15 via terminal 520 into data and outputs them to the microcomputer 518. The battery control device 5 can use the CAN signals from the CAN driver 519 to communicate with the vehicle control device 4 via the CAN communication line 15.

[0043] In addition, Figure 2 In the example shown, only one drive circuit 516 is provided for switches 501-1 and 501-2, but a separate drive circuit 516 can also be provided for each switch.

[0044] Next, use Figure 3 , 4 The flowcharts in section 5 illustrate the sequence of operations of the battery system in this embodiment.

[0045] Figure 3This is a flowchart illustrating the sequence of actions when the battery control device 5 is started normally. In step 801, the vehicle starts. In step 802, when the battery control device 5 starts normally, in step 803, the battery control device 5 outputs a drive signal 517 from the microcomputer 518 to the drive circuit 516, switching the built-in switches 501-1 and 501-2 to the ON state. Next, in step 804, the battery control device 5 outputs specified data from the microcomputer 518 to the CAN driver 519 and outputs a relay ON permission signal to the vehicle control device 4. This relay ON permission signal is a CAN signal that authorizes the high-voltage relay 2 to switch to the ON state.

[0046] When the relay activation permission signal sent from the battery control device 5 in step 804 is received, in step 805, the vehicle control device 4 switches each switch of the relay control switch 401 to the ON state. At this time, as described above, switches 401-1 and 401-2 are initially switched to the ON state. After the smoothing capacitor in the converter 1 is charged to a certain voltage, switch 401-3 is switched to the ON state, and switch 401-2 is switched to the OFF state. According to the switching of the relay control switch 401, current flows in each current path, thereby sequentially switching each relay of the high voltage relay 2 to the ON state in step 806, and starting the charging and discharging of the battery 3 in step 807.

[0047] Figure 4 This is a flowchart illustrating the sequence of actions when an abnormality is detected during the startup of the battery control device 5. In this case, the vehicle starts in step 811, and the battery control device 5 detects an abnormality during startup in step 812. Furthermore, the abnormalities detected by the battery control device 5 can range from minor to serious faults, but here we specifically assume a serious fault that would require disconnecting the converter 1 from the battery 3. Minor faults are not limited to this.

[0048] When the battery control device 5 detects an abnormality in step 812, in step 813, the battery control device 5 does not output a drive signal 517 from the microcomputer 518 to the drive circuit 516, and does not switch the built-in switches 501-1 and 501-2 to the ON state. Next, in step 814, the battery control device 5 does not output the specified data from the microcomputer 518 to the CAN driver 519, and does not output a relay ON permission signal to the vehicle control device 4.

[0049] In step 814, no relay activation permission signal is sent from the battery control device 5; therefore, in step 815, the vehicle control device 4 does not switch each switch of the relay control switch 401 to the ON state. As a result, in step 816, each relay of the high-voltage relay 2 is not switched to the ON state, and in step 817, charging and discharging of the battery 3 does not begin.

[0050] Figure 5 This is a flowchart illustrating the sequence of actions taken when an abnormality is detected after the battery control device 5 has started normally. In this case, when the vehicle starts in step 801, actions are performed up to steps 802-807 respectively. Figure 3 The same actions are performed to begin charging and discharging battery 3. Then, in step 821, when the battery control device 5 detects an abnormality while the vehicle is in motion, in step 822, the battery control device 5 outputs the prescribed data from the microcomputer 518 to the CAN driver 519 and outputs a CAN signal to the vehicle control device 4 requesting the high-voltage relay 2 to switch to the off state. Next, after a certain period of time, in step 823, the battery control device 5 stops outputting the drive signal 517 from the microcomputer 518 to the drive circuit 516 and switches the built-in switches 501-1 and 501-2 to the off state.

[0051] In step 822, upon receiving a request from the battery control unit 5 to switch the high-voltage relay 2 to the off state, the vehicle control unit 4 switches each switch of the relay control switch 401 to the off state. Alternatively, in step 823, the battery control unit 5 switches switches 501-1 and 501-2 to the off state, thereby cutting off the current flowing through each current path. As a result, in step 824, each relay of the high-voltage relay 2 is switched to the off state, and in step 825, the charging and discharging of the battery 3 is stopped.

[0052] (Second Implementation)

[0053] Figure 6 This diagram illustrates the configuration of a battery system including a battery control device according to a second embodiment of the present invention. In the battery system of this embodiment, [the following is a description of the battery system configuration and its components]. Figure 1 The difference between the battery system of the first embodiment shown and the one shown is that the other end of the three switches 401-1, 401-2, and 401-3 in the relay control switch 401 in the vehicle control device 4 that are not connected to the excitation coil is connected to the chassis GND18, and the other end of the switches 501-1 and 501-2 in the relay control switch 501 in the battery control device 5 that are not connected to the excitation coil is connected to the low-voltage power supply 11.

[0054] Thus, in the battery system of this embodiment, the three switches 401-1, 401-2, and 401-3 of the relay control switch 401 in the vehicle control device 4 are positioned on the side closer to the chassis GND18, i.e., the low-potential side, on current paths 12 to 14, compared to the excitation coils of each relay in the high-voltage relay 2. On the other hand, switches 501-1 and 501-2 of the relay control switch 501 in the battery control device 5 are positioned on the side closer to the low-voltage power supply 11, i.e., the high-potential side, on current paths 16 and 17, compared to the excitation coils of each relay in the high-voltage relay 2. Therefore, similar to the first embodiment, by switching these switches to the ON state, current can flow through the excitation coils via each current path, switching each relay of the high-voltage relay 2 to the ON state.

[0055] Furthermore, the switching method for each switch in this embodiment is the same as that described in the first embodiment. Therefore, even in the battery system of this embodiment, the system for disconnecting the converter 1 from the battery 3 is configured as a dual system through the system of the relay control switch 401 in the vehicle control device 4 and the system of the relay control switch 501 in the battery control device 5. Therefore, even if a fault occurs in either system, overcharging or over-discharging of the battery 3 can be reliably prevented.

[0056] According to the embodiments of the present invention described above, the following effects are achieved.

[0057] (1) The battery system is connected to an inverter 1 mounted on the vehicle, and performs DC power transfer between the battery system and the inverter 1. The battery system includes: a battery 3; a high-voltage relay 2 for connecting or disconnecting the connection between the battery 3 and the inverter 1; multiple relay control switches 401 and 501 respectively disposed on current paths 12-14, 16, and 17 for switching the high-voltage relay 2; and a battery control device 5 for monitoring the state of the battery 3. Relay control switch 501 is disposed within the battery control device 5, and relay control switch 401 is disposed within a vehicle control device 4 for controlling the vehicle's movement. Relay control switches 401 and 501 are connected in series on current paths 12-14, 16, and 17. The battery control device 5 controls the switching state of relay control switch 501, and relay control switch 401 controls the switching state of relay control switch 401. In this way, even if one of the battery control device 5, which controls the connection between the battery 3 and the converter 1 via the high-voltage relay 2, or the vehicle control device 4, fails, the battery 3 can be reliably prevented from being overcharged or over-discharged.

[0058] (2) A positive-side relay 201, a negative-side relay 203, and a pre-charge relay 202 are provided between the battery 3 and the converter 1 as high-voltage relays 2. Corresponding to each of these relays, a group of relay control switches 401 and 501 are respectively provided, namely, a group of switches 401-1 and 501-1; a group of switches 401-2 and 501-2; and a group of switches 401-3 and 501-2. In this way, the connection and disconnection between the battery 3 and the converter 1 can be performed safely and reliably.

[0059] (3) One of the relay control switches 401 and 501 is connected to the high-potential side of current paths 12-14, 16, and 17, and the other of the relay control switches 401 and 501 is connected to the low-potential side of current paths 12-14, 16, and 17. In this way, by switching one of the switches to the open state, the current flowing through current paths 12-14, 16, and 17 can be cut off, and the high-voltage relay 2 can be reliably made to be in the open state.

[0060] (4) Excitation coils of each relay of the high-voltage relay 2 are configured on current paths 12-14, 16, and 17 to switch according to the presence or absence of current flowing through these current paths. One of the relay control switches 401 and 501 is set on the high potential side of the current paths 12-14, 16, and 17 compared to the excitation coil, and the other of the relay control switches 401 and 501 is set on the low potential side of the current paths 12-14, 16, and 17 compared to the excitation coil. Therefore, by switching the relay control switches 401 and 501 to the ON state, current flows through the excitation coil, and each relay of the high-voltage relay 2 can be switched to the ON state.

[0061] (5) When an anomaly is detected (step 821), the battery control device 5 sends a request to the vehicle control device 4 to disconnect the high-voltage relay 2, i.e., a request to switch the high-voltage relay 2 to the open state (step 822), and switches the relay control switch 501 to the open state (step 823). Upon receiving the disconnection request, the vehicle control device 4 switches the relay control switch 401 to the open state. Therefore, in the event of an anomaly, the high-voltage relay 2 can be reliably disconnected by either the battery control device 5 or the vehicle control device 4 via the relay control switch 401 or 501.

[0062] (6) After a predetermined time has elapsed since the high-voltage relay 2 was sent to disconnect, the battery control device 5 switches the relay control switch 501 to the open state. Therefore, even if the vehicle control device 4 is unable to switch the relay control switch 401 to the open state due to a malfunction or other reasons, the high-voltage relay 2 can be reliably made to open after a predetermined time.

[0063] The embodiments and various modifications described above are merely examples, and the present invention is not limited to these contents as long as they do not impair the features of the invention. Furthermore, while various embodiments and modifications have been described above, the present invention is not limited to these contents. Even if there are changes that do not depart from the spirit of the present invention, as long as they are within the scope of the technical concept of the present invention, they are included within the scope of the present invention.

[0064] The disclosures of the following priority-based applications are incorporated herein by reference.

[0065] Japanese Patent Application 2019-214100 (filed on November 27, 2019)

[0066] Symbol Explanation

[0067] 1. Converter

[0068] 2. High-voltage relay

[0069] 3 batteries

[0070] 4. Vehicle control device

[0071] 5. Battery control device

[0072] 11 Low-voltage power supply

[0073] Current paths 12, 13, 14, 16, 17

[0074] 15 CAN communication lines

[0075] 18 Chassis GND

[0076] 19 Voltage detection lines

[0077] 20. Front-side wiring of the converter

[0078] 21 Negative-side wiring of the converter

[0079] 22 Battery front-side wiring

[0080] 23 Battery negative side wiring

[0081] 201 Positive side relay

[0082] 202 Precharge Relay

[0083] 203 Negative side relay

[0084] 204 pre-charge resistor

[0085] 301 Single Cell

[0086] 401, 501 Relay control switches.

Claims

1. An on-board battery system connected to a converter mounted on a vehicle, for transmitting and receiving DC power between itself and the converter, the on-board battery system being characterized by comprising: Battery; A relay, used to connect or disconnect the battery from the converter; Multiple switches, each disposed on a current path used for switching the relay; and A battery control device that monitors the state of the battery. The plurality of switches includes: a first switch disposed within the battery control device; and a second switch disposed within a vehicle control device for controlling the driving of the vehicle. The first switch and the second switch are connected in series in the current path and are configured such that switching one of them can cut off the current flowing in the current path, thereby switching the relay to the off state. The battery control device controls the switching state of the first switch. The vehicle control device controls the switching state of the second switch.

2. The vehicle-mounted battery system according to claim 1, characterized in that, A plurality of relays are disposed between the battery and the converter. A group of the first switch and the second switch is respectively provided corresponding to each of the plurality of relays.

3. The vehicle-mounted battery system according to claim 1, characterized in that, One of the first switch and the second switch is a high-potential side switch connected to the high-potential side of the current path. The first switch and the other of the second switch are low-potential side switches connected to the low-potential side of the current path.

4. The vehicle-mounted battery system according to claim 2, characterized in that, One of the first switch and the second switch is a high-potential side switch connected to the high-potential side of the current path. The first switch and the other of the second switch are low-potential side switches connected to the low-potential side of the current path.

5. The vehicle-mounted battery system according to claim 3, characterized in that, An excitation coil for the relay is configured on the current path to switch based on the presence or absence of current flowing through the current path. One of the first switch and the second switch is positioned on the high potential side in the current path compared to the excitation coil. The first switch and the other of the second switch are positioned on the lower potential side of the current path compared to the excitation coil.

6. The vehicle battery system according to any one of claims 1 to 5, characterized in that, When an anomaly is detected, the battery control device sends a request to the vehicle control device to disconnect the relay and switches the first switch to the off state. When the cut-off request is received, the vehicle control device switches the second switch to the off state.

7. The vehicle battery system according to claim 6, characterized in that, After a predetermined time has elapsed since the cut-off request was sent, the battery control device switches the first switch to the off state.

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