Battery control device and abnormality sensing method

Abstract

The present application discloses a battery control device and an abnormality sensing method. The battery control device controls batteries including battery blocks connected in series to perform voltage equalization of the battery blocks, in which unit batteries are connected in parallel, and the battery control device includes: a detection unit that detects the voltage between the positive and negative electrodes of each battery block; a voltage equalization circuit that includes a plurality of discharge units, wherein at least one discharge element and a switch element are connected in series; and a control unit that controls the switch element to equalize the voltage of the battery block. The discharge units are respectively connected between the positive and negative electrodes of the battery blocks. The control unit controls the switch element at a predetermined time to perform discharge of the battery block, and determines whether there is an abnormality in the battery block based on the voltage difference between the battery blocks before and after discharge.

Description

Technical Field

[0001] The present invention relates to a battery control device configured to control a battery including two or more battery blocks connected in series in each of which a plurality of unit cells are connected in parallel, and an abnormality sensing method for a battery block performed by the battery control device. Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2016-217900 (JP 2016-217900A) discloses a device that senses an abnormality occurring in a high-voltage battery for driving an electric vehicle. In JP 2016-217900A, when charging is performed with a large variation width from a low state of charge (low SOC) to a high state of charge (high SOC), by determining the voltage difference before and after charging, an abnormality in the battery can be effectively sensed. Summary of the invention

[0003] In order to realize abnormality sensing in the battery block described in JP 2016-217900A, a dedicated device having an abnormality sensing function for the battery block is separately required, thus increasing the cost of the battery control device.

[0004] The present invention has been made in view of the above disadvantages, and aims to provide a battery control device and an abnormality sensing method which can limit an increase in the cost of the battery control device due to the addition of an abnormality sensing function of a battery block.

[0005] In order to solve the above disadvantages, one solution of the present invention is a battery control device, which controls a battery including two or more battery blocks connected in series to perform voltage balancing of each battery block, in which a plurality of unit cells are connected in parallel. The battery control device includes: a detection unit configured to detect the voltage between the positive and negative electrodes of each battery block; a voltage balancing circuit including a plurality of discharge units corresponding to the battery blocks, in each of which at least one discharge element and a switch element are connected in series; and a control unit configured to control the switch element in the discharge unit to balance the voltage of each battery block. The discharge units are respectively connected between the positive and negative electrodes of the battery blocks. The control unit is configured to control the switch element at a predetermined time to perform the discharge of each battery block for the first time, and determine whether there is an abnormality in the battery block based on the voltage difference of each battery block before and after the discharge.

[0006] In addition, another embodiment of the present invention is an abnormality sensing method for a battery block, which controls a battery and is executed by a battery control device, wherein the battery includes more than two battery blocks connected in series, and a plurality of unit cells are connected in parallel in each of the battery blocks. The battery control device includes: a detection unit configured to detect the voltage between the positive and negative electrodes of each battery block, and a voltage equalization circuit including a plurality of discharge units corresponding to the battery block, in each of the discharge units, at least one discharge element and a switch element are connected in series. The plurality of discharge units are respectively connected between the positive and negative electrodes of the battery block. The abnormality sensing method includes: a step of controlling the switch element at a predetermined time to perform the discharge of each battery block for the first time; a step of calculating the voltage difference of each battery block before and after the discharge; and a step of determining whether there is an abnormality in the battery block based on the calculated voltage difference.

[0007] By utilizing the battery control device and abnormality sensing method of the present invention, since the voltage equalization circuit provided in the battery can be used to determine whether there is an abnormality in the battery block, the increase in the cost of the battery control device caused by the addition of the battery block abnormality sensing function can be limited. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, wherein like reference numerals represent like elements, and wherein:

[0009] Figure 1 is a block diagram showing a schematic configuration of a power supply system including a battery control device according to an embodiment of the present invention;

[0010] Figure 2 is a diagram showing an example of a characteristic curve of a state of charge relative to an open circuit voltage (SOC-OCV) of a lithium iron phosphate battery;

[0011] Figure 3 is a diagram showing a configuration example of a second battery;

[0012] Figure 4A is a flowchart of an abnormality sensing process for a battery block of a second battery executed by a battery control device;

[0013] Figure 4B is a flowchart of an abnormality sensing process for a battery block of a second battery executed by the battery control device, and

[0014] Figure 5 This is a diagram showing, as an image, the voltage change in each battery block before and after the discharge process. DETAILED DESCRIPTION

[0015] The battery control device and abnormality sensing method of the present invention use a voltage equalization circuit pre-set in the battery to be controlled to determine whether there is an abnormality in multiple battery blocks connected in series. In this way, the cost increase of the battery control device caused by adding a battery block abnormality sensing function can be limited.

[0016] Example

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0018] Configuration

[0019] Figure 1 : is a block diagram showing a schematic configuration of a power supply system including a battery control device according to an embodiment of the present invention. Figure 1 The illustrated power supply system 1 includes a first battery 10 , a DC-DC converter 20 , a second battery 30 , a plurality of vehicle-mounted devices 40 , and a battery control device 50 according to the present embodiment.

[0020] Figure 1 The power supply system 1 shown can be installed in a vehicle. In the following embodiment, the control of the battery control device 50 according to the present embodiment will be described by exemplifying a case where the power supply system 1 is installed in a vehicle using an electric motor as a power source such as a hybrid vehicle (HV), a plug-in hybrid vehicle (PHV), and an electric vehicle (EV).

[0021] The first battery 10 is a high-voltage battery that supplies power to a motor (not shown) or a DC-DC converter 20. In addition, the first battery 10 may be configured to obtain power from an external power source through a plug-in charger (not shown) that can be connected to the external power source. As the first battery 10, a secondary battery such as a lithium-ion battery configured to be chargeable and dischargeable is used.

[0022] The DC-DC converter 20 connects the first battery 10 to the second battery 30 and the vehicle-mounted device 40, and supplies power from the first battery 10 to the second battery 30 and the vehicle-mounted device 40. When supplied with power, the DC-DC converter 20 can convert the high voltage of the first battery 10 as an input voltage into a predetermined low voltage and output the predetermined low voltage.

[0023] The second battery 30 is a low voltage battery that is charged by the power output by the DC-DC converter 20 and discharges its own power. A typical second battery 30 installed on the vehicle is an auxiliary battery. A battery having an area (flat area) in which the absolute value of the rate of change of the open circuit voltage (OCV) relative to the state of charge (SOC) in the SOC-OCV characteristic curve representing the relationship between the SOC and OCV of the battery is equal to or less than a second value is used as the second battery 30. The second value is a predetermined value based on the specifications of the battery. An example of a battery having a flat area may be a lithium iron phosphate battery (LFP battery). Figure 2 An example of a SOC-OCV characteristic curve of a lithium iron phosphate battery is shown.

[0024] The second battery 30 includes two or more battery blocks connected in series, in which a plurality of unit cells are connected in parallel. Figure 3 A configuration example of the second battery 30 is shown. Figure 3 The second battery 30 shown in FIG. 1 includes battery blocks connected in series in the following order: a first battery block 310 in which unit cells 311 and 312 are connected in parallel, a second battery block 320 in which unit cells 321 and 322 are connected in parallel, a third battery block 330 in which unit cells 331 and 332 are connected in parallel, and a fourth battery block 340 in which unit cells 341 and 342 are connected in parallel. The configuration of the second battery 30 is not limited to Figure 3 The configuration shown may include three or more unit cells connected in parallel or two, three, five or more battery blocks connected in series, depending on the power requirements of the vehicle-mounted device 40 .

[0025] The vehicle-mounted device 40 is various vehicle-mounted devices that operate using the power output from the DC-DC converter 20 or the power from the second battery 30. Examples of the vehicle-mounted device 40 include actuators (such as motors and solenoids), lights (such as headlights and interior lights), air conditioners (such as heaters and coolers), steering gears and brakes, and electronic control units (ECUs) for autonomous driving or advanced driving assistance.

[0026] The battery control device 50 includes a voltage equalization circuit 500 , a detection unit 550 , and a control unit 560 , and controls the second battery 30 .

[0027] The voltage equalization circuit 500 performs a process of equalizing the changes in voltage (i.e., SOC) occurring between the respective battery blocks of the second battery 30 based on the instruction of the control unit 560. The change in voltage between the battery blocks is caused by the change in the self-discharge amount of each unit cell. When the voltage between the battery blocks changes, the degradation of a specific unit cell proceeds at an accelerated rate, and the amount of available energy decreases. Therefore, if necessary, these effects are avoided by discharging the battery block having a high voltage using the voltage equalization circuit 500 to reduce the voltage and align the voltage with the voltage of the other battery blocks.

[0028] The voltage equalization circuit 500 is composed of a plurality of discharge units corresponding to a plurality of battery blocks of the second battery 30 . Figure 3 FIG. 5 shows a configuration example of a voltage equalization circuit 500. Figure 3 As shown, the voltage balancing circuit 500 is composed of a first discharge unit 510 connected between the positive electrode and the negative electrode of the first battery block 310 of the second battery 30, a second discharge unit 520 connected between the positive electrode and the negative electrode of the second battery block 320 of the second battery 30, a third discharge unit 530 connected between the positive electrode and the negative electrode of the third battery block 330 of the second battery 30, and a fourth discharge unit 540 connected between the positive electrode and the negative electrode of the fourth battery block 340 of the second battery 30.

[0029] The first discharge unit 510 has a configuration in which a discharge element 512 such as a resistor and a switch element 511 such as a transistor are connected in series, and a discharge path from the positive electrode to the negative electrode of the first battery block 310 can be formed by the operation (conduction) of the switch element 511. The discharge element 512 can be inserted in the source side or the drain side of the switch element 511, or can be connected to both sides. The second discharge unit 520 has a configuration in which a discharge element 522 such as a resistor and a switch element 521 such as a transistor are connected in series, and a discharge path from the positive electrode to the negative electrode of the second battery block 320 can be formed by the operation (conduction) of the switch element 521. The discharge element 522 can be inserted in the source side or the drain side of the switch element 521, or can be connected to both sides. The third discharge unit 530 has a configuration in which a discharge element 532 such as a resistor and a switch element 531 such as a transistor are connected in series, and a discharge path from the positive electrode to the negative electrode of the third battery block 330 can be formed by the operation (conduction) of the switch element 531. The discharge element 532 can be inserted in the source side or the drain side of the switch element 531, or can be connected to both sides. The fourth discharge unit 540 has a configuration in which a discharge element 542 such as a resistor and a switch element 541 such as a transistor are connected in series, and a discharge path from the positive electrode to the negative electrode of the fourth battery block 340 can be formed by the operation (conduction) of the switch element 541. The discharge element 542 can be inserted in the source side or the drain side of the switch element 541, or can be connected to both sides.

[0030] In the voltage equalization circuit 500 according to the present embodiment, the wiring for connecting the first discharge unit 510 to the negative electrode of the first battery block 310 and the wiring for connecting the second discharge unit 520 to the positive electrode of the second battery block 320 are shared. In addition, the wiring for connecting the second discharge unit 520 to the negative electrode of the second battery block 320 and the wiring for connecting the third discharge unit 530 to the positive electrode of the third battery block 330 are shared. In addition, the wiring for connecting the third discharge unit 530 to the negative electrode of the third battery block 330 and the wiring for connecting the fourth discharge unit 540 to the positive electrode of the fourth battery block 340 are shared. By partially sharing the wiring, the circuit cost of the voltage equalization circuit 500 is reduced.

[0031] Sharing some of the above-mentioned wirings is not essential to implement the present invention, and the advantageous effects of the present invention can be obtained even when dedicated wirings are independently provided in each battery block.

[0032] The detection unit 550 detects the state of the second battery 30. The detection unit 550 includes a voltage sensor 551 that detects the voltage between the positive and negative electrodes of the first battery block 310, a voltage sensor 552 that detects the voltage between the positive and negative electrodes of the second battery block 320, a voltage sensor 553 that detects the voltage between the positive and negative electrodes of the third battery block 330, and a voltage sensor 554 that detects the voltage between the positive and negative electrodes of the fourth battery block 340. The detection unit 550 functions as a voltage detection unit. In addition, the detection unit 550 may function as a current detection unit that detects the current of the second battery 30 using a current sensor (not shown), and as a temperature detection unit that detects the temperature of the second battery 30 using a temperature sensor (not shown).

[0033] The control unit 560 acquires each value detected by the detection unit 550, and based on each acquired value, performs a process of equalizing the variation of the voltage (SOC) occurring between the respective battery blocks of the above-mentioned second battery 30. In the voltage equalization process, the control unit 560 discharges the battery block by operating the switching element of the discharge unit provided in the battery block whose voltage is to be lowered (by applying an operating voltage to the gate of the transistor).

[0034] In addition, the control unit 560 obtains information about the power operation of the vehicle, determines that the power has at least been turned off, and performs abnormal sensing processing on the battery block to be described below. Examples of information about the power operation of the vehicle may include information about the on / off of the ignition switch. Based on the result of the abnormal sensing processing on the battery block, the control unit 560 may use an information transmission unit (not shown) such as a display or a speaker to notify the user of the vehicle of information corresponding to the result. The control unit 560 may also notify a management center or the like outside the vehicle via a wireless communicator (not shown) such as a data communication module (DCM).

[0035] The control unit 560 is generally composed of an ECU including a processor, a memory, an input / output interface, etc. When the processor reads and executes a program stored in the memory, the control unit 560 according to the present embodiment performs a voltage equalization process and an abnormality sensing process on the battery blocks.

[0036] control

[0037] Will further refer to Figure 4A and Figure 4B Control performed by the battery control device 50 according to the present embodiment is described. Figure 4A and Figure 4B Each of them is a flowchart showing a procedure of abnormality sensing processing of the battery block of the second battery 30 performed by the control unit 560 of the battery control device 50 . Figure 4A Processing and Figure 4BThe processes in are connected at connectors X, Y and Z respectively.

[0038] Figure 4A and Figure 4B The abnormality sensing process for the battery block shown is started at a timing that does not affect the operation of the vehicle-mounted device 40. In the present embodiment, the process is started at a timing when the power supply of the vehicle is turned off, for example, when the ignition switch is switched from on to off.

[0039] Step S401: First, the control unit 560 of the battery control device 50 determines whether there is an abnormality in the first battery block 310, the second battery block 320, the third battery block 330, and the fourth battery block 340 constituting the second battery 30. The determination is made for the following reasons.

[0040] As described above, the abnormality sensing process is performed every time the power of the vehicle is turned off. Therefore, even when it is determined that an abnormality exists in a battery block in the abnormality sensing process performed at a specific moment, there may be a situation where measures for eliminating the abnormality have not been performed until the next time the abnormality sensing process is performed. For example, when the vehicle cannot be left at a repair shop on the day when the abnormality is notified, the vehicle is used during the day, so it is assumed that the power of the vehicle is turned on / off multiple times during the day. In addition, the abnormality sensing process is intended to detect an abnormality that has already occurred in any one battery block, and there is no need to further detect abnormalities in more than two battery blocks. Therefore, once it is determined that an abnormality exists in a battery block, the determination in step S401 is performed to limit the execution of unnecessary abnormality sensing processing until the abnormality is resolved.

[0041] When there is no abnormality in any battery block of the second battery 30 ("No" in step S401), the process proceeds to step S402, and when there is an abnormality in any battery block of the second battery 30 ("Yes" in step S401), the process proceeds to step S415.

[0042] Step S402: The control unit 560 of the battery control device 50 obtains the voltage V1b between the positive and negative electrodes of the first battery block 310 of the second battery 30 from the voltage sensor 551 of the detection unit 550. In addition, the control unit 560 obtains the voltage V2b between the positive and negative electrodes of the second battery block 320 of the second battery 30 from the voltage sensor 552 of the detection unit 550. In addition, the control unit 560 obtains the voltage V3b between the positive and negative electrodes of the third battery block 330 of the second battery 30 that is not adjacent to the first battery block 310 from the voltage sensor 553 of the detection unit 550. In addition, the control unit 560 obtains the voltage V4b between the positive and negative electrodes of the fourth battery block 340 of the second battery 30 that is not adjacent to the second battery block 320 from the voltage sensor 554 of the detection unit 550.

[0043] Step S403: The control unit 560 of the battery control device 50 determines whether all of the voltage Vlb, voltage V2b, voltage V3b, and voltage V4b of the battery block acquired from the detection unit 550 are values ​​outside the range of the flat area in the SOC-OCV characteristic curve of the unit cell. When each voltage V is within the range of the flat area, a large change in the voltage before and after the discharge process described below cannot be expected, and the sensing accuracy of the abnormality deteriorates. Therefore, in order to avoid unnecessary execution of the abnormal sensing process, the above determination is made. When a battery without a flat area in the SOC-OCV characteristic curve is used as the second battery 30, the determination in step S403 can be omitted.

[0044] When all the voltages V of the battery blocks are values ​​outside the range of the flat area ("Yes" in step S403), the processing proceeds to step S404, and when all the voltages V of the battery blocks are values ​​outside the range of the non-flat area ("No" in step S403), the abnormality sensing processing ends.

[0045] Step S404: First, the control unit 560 of the battery control device 50 performs a discharge process on the first battery block 310 and the third battery block 330 of the second battery 30 for a time t (first time). Specifically, the discharge process on the first battery block 310 is performed for a time t by operating (turning on) the switch element 511 of the first discharge unit 510 of the voltage equalization circuit 500, so that the current flows from the individual unit cells 311, 312 of the first battery block 310 to the discharge element 512. The discharge process on the third battery block 330 is performed for a time t by operating (turning on) the switch element 531 of the third discharge unit 530 of the voltage equalization circuit 500, so that the current flows from the individual unit cells 331, 332 of the third battery block 330 to the discharge element 532. The time t is appropriately set in consideration of the sensing accuracy required for the abnormality sensing process and the energy loss of the unit cells caused by the forced discharge, so as to make the discharge amount as small as possible.

[0046] Step S405: After the discharge process of the first battery block 310 and the third battery block 330 is completed, the control unit 560 of the battery control device 50 obtains the voltage V1a between the positive and negative electrodes of the first battery block 310 of the second battery 30 from the voltage sensor 551 of the detection unit 550. The control unit 560 also obtains the voltage V3a between the positive and negative electrodes of the third battery block 330 of the second battery 30 from the voltage sensor 553 of the detection unit 550.

[0047] Step S406: Next, the control unit 560 of the battery control device 50 performs a discharge process on the second battery block 320 and the fourth battery block 340 of the second battery 30 for a time t. The time t is the same as the time for performing the discharge process on the first battery block 310 and the third battery block 330 in step S404. Specifically, the discharge process on the second battery block 320 is performed by operating (turning on) the switch element 521 of the second discharge unit 520 of the voltage equalization circuit 500 for a time t, so that the current flows from the respective unit cells 321, 322 of the second battery block 320 to the discharge element 522. The discharge process on the fourth battery block 340 is performed by operating (turning on) the switch element 541 of the fourth discharge unit 540 of the voltage equalization circuit 500 for a time t, so that the current flows from the respective unit cells 341, 342 of the fourth battery block 340 to the discharge element 542.

[0048] Step S407: After the discharge process of the second battery block 320 and the fourth battery block 340 is completed, the control unit 560 of the battery control device 50 obtains the voltage V2a between the positive and negative electrodes of the second battery block 320 of the second battery 30 from the voltage sensor 552 of the detection unit 550. The control unit 560 also obtains the voltage V4a between the positive and negative electrodes of the fourth battery block 340 of the second battery 30 from the voltage sensor 554 of the detection unit 550.

[0049] like Figure 3 As shown, the processing of steps S404 to S407 is performed on the premise that the voltage equalization circuit 500 according to the present embodiment has a configuration in which adjacent battery blocks of the second battery 30 share a part of the wiring of the discharge unit. When the voltage equalization circuit 500 has such a configuration, the control unit 560 cannot perform the discharge processing on two adjacent battery blocks at the same time. Therefore, in the present embodiment, for example, the battery blocks of the second battery 30 are divided into an odd group of the first battery block 310 and the third battery block 330 and an even group of the second battery block 320 and the fourth battery block 340, and the discharge processing is performed.

[0050] Any one of the processes of steps S404 and S405 for discharging the odd groups of the first and third battery blocks 310 and 330 and the processes of steps S406 and S407 for discharging the even groups of the second and fourth battery blocks 320 and 340 may be performed first.

[0051] In addition, when the voltage equalization circuit 500 has a configuration in which five or more battery blocks are connected in series, the discharge process is performed separately for the odd-numbered battery block group and the even-numbered battery block group. Alternatively, the discharge process may be performed by grouping according to a condition in which two adjacent battery blocks are not grouped together. For example, the battery blocks may be divided into groups based on equal differences or equal magnifications of the battery block numbers.

[0052] In addition, when the voltage equalization circuit 500 has a configuration in which an independent discharge unit dedicated to each battery block is used without the adjacent battery blocks sharing a part of the wiring of the discharge unit, a plurality of adjacent battery blocks can be discharged at the same time or all battery blocks can be discharged at the same time. In addition, regardless of the configuration of the discharge unit of the voltage equalization circuit 500, each battery block can be discharged independently in sequence or randomly.

[0053] Step S408: After the discharge process of all battery blocks is completed, the control unit 560 of the battery control device 50 calculates the voltage difference ΔV1 before and after the discharge process of the first battery block 310, the voltage difference ΔV2 before and after the discharge process of the second battery block 320, the voltage difference ΔV3 before and after the discharge process of the third battery block 330, and the voltage difference ΔV4 before and after the discharge process of the fourth battery block 340 according to the following equations. The voltage difference ΔV is a positive value (absolute value of the voltage difference) obtained by subtracting the voltage after the discharge process from the voltage before the discharge process:

[0054] Voltage difference ΔV1 = voltage V1b - voltage V1a

[0055] Voltage difference ΔV2 = voltage V2b - voltage V2a

[0056] Voltage difference ΔV3 = voltage V3b - voltage V3a

[0057] Voltage difference ΔV4 = voltage V4b - voltage V4a

[0058] Step S409: The control unit 560 of the battery control device 50 compares the multiple calculated voltage differences ΔV and determines whether there is a voltage difference ΔV that is larger than the other voltage differences ΔV by a first value or more. The first value is a predetermined reference value for determining whether there is an abnormality in the battery block, and is appropriately set so that it is possible to determine whether there is an abnormality with high accuracy based on the number of parallel-connected unit cells constituting the battery block, the value (e.g., resistance value) of the discharge element included in each discharge unit of the voltage equalization circuit 500, and the time t of the discharge process. When there is a voltage difference ΔV that is larger than the other voltage differences ΔV by a first value or more ("Yes" in step S409), the process proceeds to step S410. On the other hand, when there is no voltage difference ΔV that is larger than the other voltage differences ΔV by a first value or more ("No" in step S409), the abnormality sensing process ends.

[0059] Step S410: The control unit 560 of the battery control device 50 determines which battery block has a voltage difference ΔV greater than the other voltage differences ΔV by a first value or more. When the voltage difference ΔV1 is greater than the other voltage differences ΔV2, ΔV3, and ΔV4 by a first value or more (ΔV1 in step S410), the process proceeds to step S411. When the voltage difference ΔV2 is greater than the other voltage differences ΔV1, ΔV3, and ΔV4 by a first value or more (ΔV2 in step S410), the process proceeds to step S412. When the voltage difference ΔV3 is greater than the other voltage differences ΔV1, ΔV2, and ΔV4 by a first value or more (ΔV3 in step S410), the process proceeds to step S413. When the voltage difference ΔV4 is greater than the other voltage differences ΔV1, ΔV2, and ΔV3 by a first value or more (ΔV4 in step S410), the process proceeds to step S414.

[0060] Figure 5 : is a diagram showing an image of voltage changes in each battery block before and after the discharge process. Figure 5 A case is shown where the voltage difference ΔV3 of the third battery block 330 is approximately twice the voltage difference ΔV1 of the first battery block 310, the voltage difference ΔV2 of the second battery block 320, and the voltage difference ΔV4 of the fourth battery block 340. In this case, for example, when the first value is set to a value similar to the voltage difference ΔV1, etc., it is determined that the voltage difference ΔV3 of the third battery block 330 is greater than the other voltage differences. On the other hand, when the first value is set to a value three times the voltage difference ΔV1, etc., the voltage difference ΔV3 of the third battery block 330 is not determined to be greater than the other voltage differences.

[0061] Step S411: The control unit 560 of the battery control device 50 determines that there is an abnormality in the first battery block 310 of the second battery 30. It is conceivable that an abnormality such as a break in the parallel connection of the unit cells 311, 312 constituting the first battery block 310 has occurred.

[0062] Step S412: The control unit 560 of the battery control device 50 determines that there is an abnormality in the second battery block 320 of the second battery 30. It is conceivable that an abnormality such as a break in the parallel connection of the unit cells 321, 322 constituting the second battery block 320 has occurred.

[0063] Step S413: The control unit 560 of the battery control device 50 determines that there is an abnormality in the third battery block 330 of the second battery 30. It is conceivable that an abnormality such as a break in the parallel connection of the unit cells 331, 332 constituting the third battery block 330 has occurred.

[0064] Step S414: The control unit 560 of the battery control device 50 determines that there is an abnormality in the fourth battery block 340 of the second battery 30. It is conceivable that an abnormality such as a disconnection in the parallel connection of the unit cells 341, 342 constituting the fourth battery block 340 has occurred.

[0065] Step S415: The control unit 560 of the battery control device 50 notifies the user of the vehicle, a management center outside the vehicle, etc. of information indicating that an abnormality exists in the second battery 30 or a specific battery block of the second battery 30 via a predetermined information transmitter or a wireless communicator. The notified information may include a message prompting a designated repair shop such as a vehicle dealer to inspect or repair the vehicle. When the abnormality notification is sent, the abnormality sensing process ends.

[0066] The notification may be sent when an abnormality is determined, or may be sent when the power of the vehicle is turned on next time. Moreover, the notification may be displayed for a certain period of time and deleted, or may be displayed until appropriate actions such as inspection and repair are performed.

[0067] Beneficial Effects

[0068] As described above, with the battery control device and the abnormality sensing method according to the embodiment of the present invention, a predetermined discharge process is performed using a voltage equalization circuit including a discharge unit connected between the positive and negative electrodes of each battery block of the battery to be controlled (the second battery 30). Then, the battery control device determines whether there is an abnormality in the battery block based on the voltage difference of each battery block before and after the discharge process.

[0069] As described above, since it is possible to determine whether there is an abnormality in a battery block using a voltage equalization circuit pre-set in a battery to be controlled, it is possible to limit the cost increase of the battery control device due to the addition of a battery block abnormality sensing function.

[0070] Furthermore, in the abnormality sensing method performed by the battery control device according to the present embodiment, since it is only necessary to acquire the voltage difference obtained by discharging when the discharge amount is as small as possible, it is possible to determine whether there is an abnormality in a battery block with low energy loss.

[0071] In addition, in the abnormality sensing method performed by the battery control device according to the present embodiment, the voltage equalization circuit is controlled so that two adjacent battery blocks are not discharged at the same time. Therefore, even when the voltage equalization circuit provided in the battery to be controlled has a configuration of sharing a part of the wiring of the discharge unit, abnormality sensing processing for the battery block can be performed.

[0072] Furthermore, in the battery control device according to the present embodiment, when the voltage of the battery block of the battery to be controlled is outside the range of the flat region in the SOC-OCV characteristic curve, abnormality sensing processing is performed. Therefore, even for an LFP battery having a flat region in the SOC-OCV characteristic curve, it is possible to determine with high accuracy whether an abnormality exists in the battery block.

[0073] Although the embodiments of the present invention have been described above, the present invention is not limited to a battery control device and an abnormality sensing method performed by a battery control device including a processor and a memory. For example, the present invention may be understood as a control program of an abnormality sensing method, a computer-readable non-transitory storage medium storing the control program, or a vehicle equipped with a battery control device.

[0074] The battery control device and abnormality sensing method of the present invention may be used to control a battery including two or more battery blocks connected in series, in which a plurality of unit batteries are connected in parallel.

Claims

1. A battery control device that controls a battery including two or more battery blocks connected in series to perform voltage balancing of each of the battery blocks, in each of which a plurality of unit cells are connected in parallel, the battery control device comprising: a detection unit configured to detect a voltage between a positive electrode and a negative electrode of each of the battery blocks; A voltage equalization circuit, comprising a plurality of discharge units corresponding to the battery blocks, wherein at least one discharge element and a switch element are connected in series in each of the discharge units, and the discharge units are respectively connected between the positive electrode and the negative electrode of the battery block; as well as a control unit configured to control the switch element in the discharge unit to equalize the voltage of each of the battery blocks, wherein the control unit is configured to control the switch element at a predetermined time to perform the discharge of each of the battery blocks for the first time, and determine whether there is an abnormality in the battery block based on the voltage difference of each of the battery blocks before and after the discharge; The control unit is further configured to: When the predetermined time arrives, When it is determined in the last abnormality sensing process that no abnormality exists in the battery block, or the abnormality of the battery block determined in the last abnormality sensing process is eliminated, re-performing the abnormality sensing process; If the abnormality of the battery block determined in the abnormality sensing process up to the last time has not been resolved, the abnormality sensing process is not performed but notification of the abnormality is performed.

2. The battery control device according to claim 1, wherein: A portion of the wiring of the voltage equalization circuit is shared by two adjacent battery blocks; and The control unit is configured to sequentially control one or more switching elements so as not to discharge the two adjacent battery blocks at the same time.

3. The battery control device according to claim 1 or 2, wherein: The control unit is configured to determine that an abnormality exists in one of the battery blocks when an absolute value of the voltage difference of the one battery block is greater than an absolute value of the voltage difference of all other battery blocks of the battery blocks by a first value or more.

4. The battery control device according to claim 1 or 2, wherein: In the state of charge versus open circuit voltage characteristic curve, the unit cell has a region where an absolute value of a rate of change of the open circuit voltage relative to the state of charge is equal to or less than a second value; and The control unit is configured to determine whether there is an abnormality in the battery block when the voltage of each of the battery blocks detected by the detection unit is a value outside the range of the area where the absolute value of the change rate of the open circuit voltage with respect to the charging state is equal to or less than the second value.

5. The battery control device according to claim 1 or 2, wherein: The battery is mounted on a vehicle; and The predetermined time is the time when the power supply of the vehicle is cut off.

6. The battery control device according to claim 5, wherein: The battery is an auxiliary battery.

7. A method for sensing an abnormality of a battery block, which controls a battery and is performed by a battery control device, the battery comprising two or more battery blocks connected in series, a plurality of unit cells being connected in parallel in each of the battery blocks, the battery control device comprising: a detection unit configured to detect a voltage between a positive electrode and a negative electrode of each of the battery blocks; and a voltage equalization circuit, comprising a plurality of discharge units corresponding to the battery block, wherein at least one discharge element and a switch element are connected in series in each of the discharge units, and the discharge units are respectively connected between the positive electrode and the negative electrode of the battery block, and the abnormality sensing method comprises: controlling the switch element at a predetermined time to perform the discharge of each of the battery blocks for the first time; calculating the voltage difference of each of the battery blocks before and after the discharge; and determining whether there is an abnormality in the battery block based on the calculated voltage difference; The abnormality sensing method further comprises: When the scheduled time arrives If it is determined that the battery block has no abnormality in the last abnormality sensing process or the abnormality of the battery block determined in the last abnormality sensing process has been resolved, re-performing the abnormality sensing process; If the abnormality of the battery block determined in the abnormality sensing process up to the last time has not been resolved, the abnormality sensing process is not performed but notification of the abnormality is performed.

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