On-vehicle system, secondary battery management system, and charging rate output method

Abstract

This invention provides an in-vehicle system for obtaining the capacity of a secondary battery with high accuracy, a secondary battery management system, a method for outputting the charging rate, and a storage medium. One aspect of the in-vehicle system includes: an acquisition unit that acquires a signal indicating the voltage of a secondary battery mounted in a vehicle; a power supply unit that supplies power to an auxiliary device or the secondary battery mounted in the vehicle using power supplied from an external power source; and an output unit that outputs the charging rate of the secondary battery based on the signal indicating the voltage of the secondary battery acquired by the acquisition unit. The power supply unit controls the output power in a manner that keeps the stored power of the secondary battery constant even when the vehicle is stopped and the charging rate of the secondary battery is being output.

Description

Technical Field

[0001] The invention relates to a vehicle-mounted system, a secondary battery management system, a charging rate output method and a storage medium. Background Art

[0002] Conventionally, as a technique for estimating the capacity of a secondary battery mounted on a vehicle, there is a technique described in Japanese Patent Application Laid-Open No. 2015-14487. The vehicle battery management device described in Japanese Patent Application Laid-Open No. 2015-14487 determines the degree of deterioration of the secondary battery based on changes in the charge level based on the charge and discharge amounts of the secondary battery and the travel distance of the vehicle. Summary of the invention

[0003] However, when measuring the charge level, if the vehicle is running and auxiliary equipment mounted on the vehicle is consuming electric power, there is a possibility that the charge level cannot be acquired with high accuracy.

[0004] One of the objects of the aspects of the present invention is to obtain the capacity of a secondary battery with high accuracy.

[0005] The vehicle-mounted system of the first scheme of the present invention comprises: an acquisition unit, which acquires a signal indicating the voltage of a secondary battery mounted on a vehicle; a power supply unit, which uses the power supplied from an external power supply device to supply the power to an auxiliary machine mounted on the vehicle or the secondary battery; and an output unit, which outputs the charging rate of the secondary battery based on the signal indicating the voltage of the secondary battery obtained by the acquisition unit, wherein the power supply unit controls the output power in a manner that keeps the stored power of the secondary battery constant when the vehicle is stopped and the charging rate of the secondary battery is output.

[0006] A second embodiment of the present invention is based on the vehicle-mounted system of the first embodiment, and may be that when the vehicle is stopped and the charging rate of the secondary battery is output, the power supply unit uses the power supplied from the external power supply device to output power equivalent to the power consumption of the auxiliary machine.

[0007] According to a third aspect of the present invention, in the vehicle-mounted system of the first or second aspect, the signal indicating the voltage of the secondary battery may be a signal indicating a voltage equivalent to an open circuit voltage of the secondary battery.

[0008] A fourth scheme of the present invention is a secondary battery management system, comprising: a vehicle-mounted system of any one of the first to third schemes described above; and a degradation output unit, which outputs the degradation of the secondary battery based on changes in a first charging rate and a second charging rate, wherein the first charging rate is output based on information representing the voltage of the secondary battery obtained by the acquisition unit at a first time when the vehicle stops and the power supply unit is controlled in a manner such that the stored power of the secondary battery is constant, and the second charging rate is output based on information representing the voltage of the secondary battery obtained by the acquisition unit at a second time when the vehicle stops and the power supply unit is controlled in a manner such that the stored power of the secondary battery is constant.

[0009] The charging rate output method of the fifth scheme of the present invention has the following processing: obtaining a signal representing the voltage of a secondary battery mounted on a vehicle; using the power supplied from an external power supply device to supply the power to an auxiliary machine mounted on the vehicle or the secondary battery; and outputting the charging rate of the secondary battery based on the signal representing the voltage of the secondary battery. The charging rate output method controls the output power in a manner that keeps the stored power of the secondary battery constant when the vehicle is stopped and the charging rate of the secondary battery is output.

[0010] The sixth scheme of the present invention is a storage medium storing a program, wherein the program causes a computer of a vehicle-mounted system to perform the following processing: obtaining a signal indicating the voltage of a secondary battery mounted on a vehicle; supplying the power to an auxiliary machine mounted on the vehicle or the secondary battery using power supplied from an external power supply device; and outputting a charging rate of the secondary battery based on the signal indicating the voltage of the secondary battery, wherein the program causes the computer of the vehicle-mounted system to control the output power in a manner that keeps the stored power of the secondary battery constant when the vehicle is stopped and the charging rate of the secondary battery is output.

[0011] According to the first to third, fifth and sixth aspects, when the vehicle is stopped and the charging rate of the secondary battery is output, the output power of the power supply unit is controlled so that the stored power of the secondary battery is constant, thereby enabling the capacity of the secondary battery to be obtained with high accuracy.

[0012] According to the fourth aspect, the secondary battery degradation is output based on the first and second charging rates output at the first and second timings based on the information indicating the voltage of the secondary battery acquired by the acquisition unit. This improves the accuracy of outputting the secondary battery degradation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a block diagram showing an example of a V2G system according to an embodiment.

[0014] Figure 2 This is a block diagram showing an example of a vehicle-mounted system according to an embodiment.

[0015] Figure 3 1 is a sequence diagram showing an example of a process of estimating the SOC of the V2G system according to the embodiment.

[0016] Figure 4 1 is a sequence diagram showing another example of the SOC estimation process of the V2G system according to the embodiment.

[0017] Figure 5 This is a flowchart showing an example of a procedure for diagnosing deterioration of a secondary battery based on SOC according to the embodiment. DETAILED DESCRIPTION

[0018] Hereinafter, the vehicle-mounted system, the secondary battery management system, the charging rate output method and the program implementation method of the present invention will be described with reference to the accompanying drawings. In the following description, the vehicle is assumed to be an electric vehicle equipped with a secondary battery, but the vehicle may also be a hybrid vehicle or a fuel cell vehicle as long as it can store power from the outside and is equipped with a secondary battery for supplying power for driving.

[0019] [Overview of V2G (Vehicle to Grid) system]

[0020] Figure 1 1 is a block diagram showing an example of a V2G system 1 according to an embodiment. The V2G system 1 is a system for transferring power between a power system (not shown) including a commercial power grid and a vehicle V. The V2G system 1 includes, for example, an on-board system 100, an external power supply device 200, and a power operator server device 300. It should be noted that the V2G system 1 according to the embodiment describes one vehicle V and an external power supply device 200, but may also include a plurality of vehicles V and external power supply devices 200.

[0021] The vehicle V includes, for example, the in-vehicle system 100 , a connection port 404A, and a motor (not shown) for traveling. A plug 402A of the cable 400 is connected to the connection port 404A.

[0022] The vehicle V exchanges electric power with the external power supply device 200 via the cable 400. It should be noted that the cable 400 is a power supply cable and may include a signal line. Alternatively, the cable 400 may be a power supply cable with a signal superimposed thereon.

[0023] The external power supply device 200 is, for example, installed at the home of the user of the vehicle V. The external power supply device 200 includes, for example, a connection port 404B and a control unit 210. A plug 402B of a cable 400 is connected to the connection port 404B. The external power supply device 200 transfers and receives power to and from the vehicle V via the cable 400. The control unit 210 sends and receives information to and from the vehicle system 100. The external power supply device 200 is connected to the power operator server device 300 via the communication network NW. The external power supply device 200 is connected to a power system including a commercial power grid. It should be noted that the network NW includes, for example, the Internet, a WAN (Wide Area Network), a LAN (Local Area Network), a provider device, a wireless base station, and the like.

[0024] The power company server device 300 is a server device used by the power company. The power company server device 300 is connected to the external power supply device 200 via the communication network NW.

[0025] The power company server device 300 controls the supply of power from the external power supply device 200 to the vehicle V, and controls the transfer of power between the power system including the commercial power grid and the vehicle V.

[0026] Figure 2 The in-vehicle system 100 includes, for example, a power supply unit 110 , a battery control unit 120 , an auxiliary device 130 , a control unit 140 , and a communication unit 150 .

[0027] The power supply unit 110 is, for example, an on-board charger (OBC) including a DC-DC converter, a relay, etc. The power supply unit 110 supplies the power supplied from the external power supply device 200 to the battery control unit 120 and the auxiliary machine 130. In addition, the power supply unit 110 supplies the power discharged from the secondary battery 122 to the auxiliary machine 130.

[0028] The battery control unit 120 is, for example, an IPU (Intelligent Power Unit). The battery control unit 120 includes, for example, a secondary battery 122, a current sensor 124, and a voltage sensor 126. Although not shown in the figure, the battery control unit 120 may also include a DCDC converter, a temperature sensor, etc. The secondary battery 122 is, for example, a lithium-ion battery. The secondary battery 122 charges the power supplied from the power supply unit 110 and discharges the charged power. The current sensor 124 detects the current during the charge and discharge of the secondary battery 122. The voltage sensor 126 detects the voltage at both ends of the secondary battery 122.

[0029] The auxiliary machine 130 is, for example, an air conditioner of the vehicle V. The auxiliary machine 130 operates by consuming the electric power supplied from the electric power supply unit 110 or the electric power supplied from the battery control unit 120 .

[0030] The control unit 140 is, for example, an ECU (Electronic Control Unit). The control unit 140 can be implemented by executing a program (software) by a hardware processor such as a CPU (Central Processing Unit). A part or all of the control unit 140 can be implemented by hardware (including a circuit unit: circuitry) such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), GPU (Graphics Processing Unit), etc., or it can be implemented by the cooperation of software and hardware. The program can be stored in advance in a storage device such as an HDD (Hard Disk Drive) or a flash memory (a storage device with a non-temporary storage medium), or it can be stored in a removable storage medium such as a DVD or CD-ROM (a non-temporary storage medium), and installed by assembling the storage medium on the drive device. The control unit 140 controls the power supply unit 110 and the battery control unit 120. In addition, the control unit 140 functions as an output unit that outputs the SOC (State of Charge) of the secondary battery 122. The control unit 140 also functions as a degradation output unit that outputs degradation of the secondary battery 122 based on the difference in SOC between the first and second timings. The SOC of the secondary battery 122 is a ratio of the remaining capacity, which is the storage capacity, to the fully charged capacity.

[0031] The communication unit 150 is, for example, a TCU (Telematics Control Unit) and transmits and receives information to and from the power company server device 300 .

[0032] Figure 3 1 is a sequence diagram showing an example of the SOC estimation process of the V2G system according to the embodiment. It should be noted that, in the embodiment, the process of estimating the SOC is described, but the estimation of the SOC is an example of the output of the SOC and is not limited to the estimated SOC.

[0033] First, the power operator server device 300 sends a preliminary request to the vehicle-mounted system 100 (step S100). The preliminary request is a request to move to a mode of waiting for a request from the power operator server device 300. The communication unit 150 receives the preliminary request and supplies the preliminary request to the control unit 140. The communication unit 150 and the control unit 140 perform a predetermined preliminary process (step S102). The communication unit 150 enters a standby state for receiving a request from the power operator server device 300 according to the preliminary request, and the control unit 140 enters a standby state for processing corresponding to the request from the power operator server device 300.

[0034] Next, the power operator server device 300 sends an SOC estimation mode request to the communication unit 150 (step S104). The SOC estimation mode request is information requesting a shift to an operation mode for estimating the SOC of the secondary battery 122. The SOC estimation mode request is supplied to the control unit 140 via the communication unit 150. The control unit 140 outputs a request to control the battery control unit 120 and the power supply unit 110 in a manner to perform an operation in the SOC estimation mode.

[0035] It should be noted that the power company server device 300 sends a preliminary request and an SOC estimation mode request to the in-vehicle system 100, for example, when the vehicle V is stopped, the vehicle V is connected to the cable 400, and power can be supplied from the external power supply device 200 to the auxiliary device 130 of the vehicle V.

[0036] The power supply unit 110 controls the output power in such a manner that the power supplied from the external power supply device 200 is supplied to the auxiliary machine 130 (step S106). For example, the power supply unit 110 requests the power required for the auxiliary machine 130 to operate from the external power supply device 200, and the external power supply device 200 requests the power required for the auxiliary machine 130 to operate from the power supply unit 110 to the power company server device 300. As a result, the external power supply device 200 receives the power required for the auxiliary machine 130 to operate from the power company and supplies it to the power supply unit 110, and the power supply unit 110 supplies the power required for the auxiliary machine 130 to operate to the auxiliary machine 130 (steps S106 and S108). As a result, when the vehicle V stops and the SOC of the secondary battery 122 is estimated, the control unit 140 controls the output power in such a manner that the stored power of the secondary battery 122 is constant. It should be noted that the battery control unit 120 can control in such a manner that the charging power and the discharging power of the secondary battery 122 are zero (step S108). The battery control unit 120 cuts off the electrical connection between the power supply unit 110 and the auxiliary device 130 and the secondary battery 122 by controlling, for example, a DCDC converter, a relay, or the like.

[0037] Next, the battery control unit 120 (acquisition unit) outputs the signal indicating the voltage Vbat of the secondary battery 122 detected by the voltage sensor 126 to the control unit 140, and the control unit 140 acquires the signal indicating the voltage Vbat. The signal indicating the voltage of the secondary battery 122 is a signal indicating a voltage equivalent to the open circuit voltage of the secondary battery 122. The control unit 140 estimates the SOC of the secondary battery 122 based on the acquired signal indicating the voltage Vbat (step S110). The control unit 140 may estimate the SOC based on table data indicating the correspondence between the signal indicating the voltage Vbat and the SOC of the secondary battery 122, or may estimate the SOC based on a calculation formula for calculating the SOC using the signal indicating the voltage Vbat.

[0038] Figure 4 1 is a sequence diagram showing another example of the SOC estimation process of the V2G system of the embodiment. First, the power operator server device 300 sends a preliminary request to the vehicle-mounted system 100 (step S100). The communication unit 150 receives the preliminary request and supplies the preliminary request to the control unit 140. The communication unit 150 and the control unit 140 perform a predetermined preliminary process (step S102). Next, the power operator server device 300 sends an SOC estimation mode request to the communication unit 150 (step S104). The SOC estimation mode request is supplied to the control unit 140 via the communication unit 150. The control unit 140 outputs a request to control the battery control unit 120 and the power supply unit 110 in a manner of performing an action in the SOC estimation mode. It should be noted that the power operator server device 300, for example, sends a preliminary request and an SOC estimation mode request to the vehicle-mounted system 100 when the vehicle V is stopped, the vehicle V is connected to the cable 400, and power can be supplied from the external power supply device 200 to the auxiliary machine 130 of the vehicle V.

[0039] The battery control unit 120 discharges the power required for the operation of the auxiliary machine 130 from the secondary battery 122 (step S120). Next, the battery control unit 120 outputs a signal indicating the current Ibat of the secondary battery 122 detected by the current sensor 124 to the control unit 140, and outputs a signal indicating the voltage Vbat of the secondary battery 122 detected by the voltage sensor 126 to the control unit 140, and the control unit 140 obtains the signal indicating the current Ibat and the signal indicating the voltage Vbat.

[0040] The control unit 140 calculates the electric power obtained by multiplying the current Ibat and the voltage Vbat (step S122 ). The control unit 140 requests the electric power supply unit 110 to charge the calculated electric power into the secondary battery 122 .

[0041] The power supply unit 110 receives the power calculated by the control unit 140 from the external power supply device 200 according to the request from the control unit 140, and charges the received power into the secondary battery 122 (step S124). Thus, the control unit 140 controls the vehicle V to keep the stored power of the secondary battery 122 constant when the vehicle V stops and the SOC of the secondary battery 122 is estimated. Next, the battery control unit 120 outputs the signal indicating the voltage Vbat of the secondary battery 122 detected by the voltage sensor 126 to the control unit 140, and the control unit 140 obtains the signal indicating the voltage Vbat. The signal indicating the voltage of the secondary battery 122 is a signal indicating a voltage equivalent to the open circuit voltage of the secondary battery 122. The control unit 140 estimates the SOC of the secondary battery 122 based on the obtained signal indicating the voltage Vbat (step S126).

[0042] Figure 5 1 is a flowchart showing an example of a step of diagnosing the degradation of the secondary battery 122 based on the SOC according to the embodiment. It should be noted that the embodiment describes the process of diagnosing the degradation of the secondary battery 122, but the process of diagnosing the degradation of the secondary battery 122 is an example of the process of outputting the degradation of the secondary battery 122 and is not limited to diagnosing the degradation of the secondary battery 122.

[0043] The control unit 140 detects Vbat, which is a voltage equivalent to the open circuit voltage of the secondary battery 122, at the first timing t1 (step S200). The first timing t1 is, for example, a timing when the vehicle V stops, the cable 400 is connected to the vehicle V, and the charging power and the discharging power of the secondary battery 122 are controlled to be zero, or the storage power of the secondary battery 122 is controlled to be constant. The control unit 140 estimates SOC (t1) based on the voltage Vbat detected at time t1 (step S202).

[0044] The control unit 140 detects Vbat, which is a voltage equivalent to the open circuit voltage of the secondary battery 122, at the second timing t2 (step S204). The second timing t2 is, for example, a timing when the vehicle V is driven after the first timing t1, the vehicle V is stopped again, the cable 400 is connected to the vehicle V, and the charging power and the discharging power of the secondary battery 122 are controlled to be zero, or the storage power of the secondary battery 122 is controlled to be constant. The control unit 140 estimates SOC (t2) based on the voltage Vbat detected at the second timing t2 (step S206).

[0045] The control unit 140 diagnoses degradation of the secondary battery 122 based on ΔSOC, which is the difference between SOC(t1) and SOC(t2) (step S208). The control unit 140 diagnoses degradation of the secondary battery 122 based on ΔSOC and the travel distance from the first timing t1 to the second timing t2, for example.

[0046] As described above, according to the vehicle-mounted system 100 of the embodiment, the charging rate of the secondary battery 122 can be output based on the signal indicating the voltage of the secondary battery 122 obtained by the voltage sensor 126 in a state where the power supply unit 110 is controlled so as to keep the stored power of the secondary battery 122 constant. As a result, according to the vehicle-mounted system 100 of the embodiment, the SOC of the secondary battery 122 can be obtained with high accuracy. In addition, according to the vehicle-mounted system 100 of the embodiment, the accuracy of outputting the deterioration of the secondary battery 122 using the SOC can be improved.

[0047] According to the vehicle-mounted system 100 of the embodiment, when the vehicle V stops and the SOC of the secondary battery 122 is output, the output power of the power supply unit 110 is controlled in such a manner that the stored power of the secondary battery 122 is constant. Therefore, the voltage equivalent to the open circuit voltage of the secondary battery 122 can be detected and the SOC can be output, thereby improving the accuracy of the SOC.

[0048] According to the in-vehicle system 100 of the embodiment, the SOC estimated by making the stored power of the secondary battery 122 constant is used, so that the accuracy of outputting the degradation of the secondary battery 122 can be improved.

[0049] In the above, the specific embodiments of the present invention are described using the embodiments, but the present invention is not limited to such embodiments at all, and various modifications and substitutions can be applied without departing from the scope of the main purpose of the present invention. The above embodiments describe the V2G system 1, but are not limited to this, and can also be applied to a V1G system that supplies power in a single direction from the external power supply device 200 to the vehicle-mounted system 100. In addition, the V2G system 1 of the above embodiments includes a diagnostic unit for diagnosing the deterioration of the secondary battery 122 in the vehicle V, but is not limited to this. It is also possible that the vehicle V does not have a diagnostic unit, but has a cloud server device that diagnoses the deterioration of the secondary battery 122 based on the SOC obtained from the vehicle V via the communication network.

Claims

1. A vehicle-mounted system, wherein: The vehicle-mounted system comprises: an acquisition unit that acquires a signal indicating a voltage of a secondary battery mounted on the vehicle; a power supply unit that uses power supplied from an external power supply device to supply the power to an auxiliary machine mounted on the vehicle or the secondary battery; and a control unit that estimates a charging rate of the secondary battery based on the signal indicating the voltage of the secondary battery acquired by the acquisition unit, When the vehicle is stopped and the charge rate of the secondary battery is estimated, the control unit uses the power supplied from the external power supply device to output power equivalent to the power consumption of the auxiliary machine, and controls the power supply unit in such a manner that the charge rate of the secondary battery is constant, thereby estimating the charge rate of the secondary battery in this state.

2. The vehicle-mounted system according to claim 1, wherein: The signal indicating the voltage of the secondary battery is a signal indicating a voltage corresponding to the open circuit voltage of the secondary battery.

3. A secondary battery management system, wherein: The secondary battery management system comprises: The vehicle-mounted system according to claim 1 or 2; and A degradation output unit that outputs degradation of the secondary battery based on changes in a first charging rate and a second charging rate, wherein the first charging rate is output based on information indicating the voltage of the secondary battery obtained by the acquisition unit at a first time when the vehicle stops and the power supply unit is controlled in a manner such that the stored power of the secondary battery is constant, and the second charging rate is output based on information indicating the voltage of the secondary battery obtained by the acquisition unit at a second time when the vehicle stops and the power supply unit is controlled in a manner such that the stored power of the secondary battery is constant.

4. A method for outputting a charging rate, wherein: The output method of the charging rate has the following processing: obtaining a signal indicating a voltage of a secondary battery mounted on the vehicle; supplying the electric power to an auxiliary machine mounted on the vehicle or the secondary battery using the electric power supplied from an external power supply device; as well as estimating a charging rate of the secondary battery based on a signal indicating a voltage of the secondary battery, The estimation includes: when the vehicle is stopped, using the power supplied from the external power supply device to output power equivalent to the power consumption of the auxiliary machine, and controlling the output power of the secondary battery in a manner to make the charging rate of the secondary battery constant, thereby estimating the charging rate of the secondary battery in this state.

5. A storage medium storing a program, wherein: The program causes the computer of the vehicle-mounted system to execute the following processing: obtaining a signal indicating a voltage of a secondary battery mounted on the vehicle; supplying the electric power to an auxiliary machine mounted on the vehicle or the secondary battery using the electric power supplied from an external power supply device; as well as estimating a charging rate of the secondary battery based on a signal indicating a voltage of the secondary battery, The estimation includes: when the vehicle is stopped, using the power supplied from the external power supply device to output power equivalent to the power consumption of the auxiliary machine, and controlling the output power of the secondary battery in a manner to make the charging rate of the secondary battery constant, thereby estimating the charging rate of the secondary battery in this state.

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