Battery unit and battery monitoring device

Abstract

A battery unit (11) configured so as to be replaceable with respect to an external load (13) is provided with: a battery unit (22) capable of supplying power to the external load in a state in which the battery unit is attached to the external load (13); a load unit (80) connected to the battery unit; a measurement unit (31) that measures at least one of a current flowing through the load unit and a voltage applied to the load unit; and a control unit (32) configured so as to operate the battery unit as a power source in a state in which the battery cell is detached from an external load, and so as to cause a current to flow from the battery unit to the load unit at a predetermined timing, and so as to acquire a measurement result measured by the measurement unit at the time.

Description

Citation of related applications

[0001] This application is based on Japanese Patent Application No. 2022-089528 filed on June 1, 2022, and the contents thereof are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to a battery cell and a battery monitoring device. Background Art

[0003] There are known disclosures that grasp the degree of degradation of each battery cell constituting a battery module after the battery module is removed from the battery pack. For example, in the disclosure described in Patent Document 1, the degree of degradation is calculated before the battery module is removed from the battery pack, and the calculated degree of degradation is sent to an external device. Then, after the battery module is removed from the battery pack, the external device is referenced. In this way, the degree of degradation of the battery cell can be grasped. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2021-163650 Summary of the invention

[0005] After the battery module is removed from the battery pack, the storage environment of the battery module becomes different. Depending on the storage environment, the degradation of the battery cells that constitute the battery module may be aggravated. Therefore, it is necessary to grasp the degradation degree of the battery cells after the battery module is removed. However, in the disclosure recorded in Patent Document 1, since no charging or discharging is performed after the battery module is removed, only the degradation degree before removal can be grasped, and the degradation degree after removal cannot be grasped.

[0006] The present disclosure has been made in view of the above technical problems, and an object of the present disclosure is to provide a battery cell and a battery monitoring device capable of grasping the battery status after a replaceable battery cell is removed.

[0007] The present invention discloses a battery unit, wherein the battery unit is configured to be replaceable relative to an external load, and the battery unit comprises: a battery unit capable of supplying electric power to the external load in a state where the battery unit is mounted on the external load; a load unit connected to the battery unit; a measuring unit that measures at least one of a current flowing in the load unit and a voltage applied to the load unit; and The control unit is configured to operate the battery unit as a power source when the battery unit is removed from the external load, and to flow current from the battery unit to the load unit at a predetermined time, and to obtain a measurement result measured by the measurement unit at this time.

[0008] The battery unit discharges the battery part at a predetermined time to measure the current, etc. The measured current, etc. can be used, for example, to calculate the battery state. As described above, in the prior art, since charging and discharging are not performed after removal, it is impossible to grasp the battery state after removal. In contrast, in the present disclosure, since the battery part is discharged to obtain the measurement result, it is possible to grasp the battery state after removal.

[0009] The present invention discloses a battery unit, wherein the battery unit is configured to be replaceable relative to an external load, and the battery unit comprises: a battery unit capable of supplying electric power to the external load in a state where the battery unit is mounted on the external load; and The control unit is configured to operate the battery unit as a power source and calculate a change in a self-discharge rate of the battery unit in a state where the battery unit is detached from the external load.

[0010] The calculated change in the self-discharge rate can be used, for example, to calculate the battery state. Since the change in the self-discharge rate can be calculated without adding new functions or devices, it contributes to cost reduction when calculating the battery state. The present invention discloses a battery monitoring device, which is installed in a battery unit configured to be replaceable relative to an external load, and includes: a measuring unit configured to measure at least one of a current flowing through a load unit connected to the battery unit of the battery cell and a voltage applied to the load unit; and The control unit is configured to operate the battery unit as a power source when the battery unit is removed from the external load, and to flow current from the battery unit to the load unit at a predetermined time, and to obtain a measurement result measured by the measurement unit at this time.

[0012] The battery monitoring device discharges the battery unit at a predetermined time to measure the current, etc. The measured current, etc. can be used, for example, to calculate the battery status. As described above, in the prior art, since charging and discharging are not performed after removal, it is impossible to grasp the battery status after removal. In contrast, in the present disclosure, since the battery unit is discharged to obtain the measurement result, it is possible to grasp the battery status after removal. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The above objects, other objects, features and advantages of the present disclosure will become more apparent with reference to the accompanying drawings and the following detailed description. Figure 1 It is a structural diagram of the vehicle. Figure 2 This is a three-dimensional image of the inside of the battery pack. Figure 3 is a block diagram showing a battery control device and a battery monitoring device. Figure 4 It is a block diagram showing a state where the battery pack is removed. Figure 5 It is a block diagram showing a state where the battery module is removed. Figure 6 This is a block diagram for determining whether the battery pack is removed. Figure 7 1 is a block diagram showing a part of the functions of a battery control device implemented by a battery monitoring device. Figure 8 1 is a block diagram showing a part of the functions of a battery control device implemented by a battery monitoring device. Fig. 9 This is a flowchart for explaining an operation example of the battery monitoring device according to the first embodiment. Fig.10 This is a flowchart for explaining an operation example of the battery monitoring device according to the second embodiment. Fig.11 It is a block diagram for explaining other embodiments. Fig.12 It is a block diagram for explaining other embodiments. DETAILED DESCRIPTION

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the description of the drawings, the same parts are denoted by the same reference numerals and description thereof will be omitted.

[0015] <First embodiment> Reference Figure 1-2 , a structural example of a battery pack 11 mounted on a vehicle 10 is described.

[0016] <Overall Structure of Vehicle 10> Figure 1 1 is a diagram schematically showing the structure of a vehicle 10. The vehicle 10 includes a battery pack 11 (in Figure 1 Power control unit (hereinafter referred to as "PCU (Power Control Unit)" 12; electric motor 13 (in Figure 1 and the vehicle ECU 14 (indicated as "MG" in Figure 1 Here, an embodiment in which the battery pack 11 is applied to the vehicle 10 is described, but the battery pack 11 of the present disclosure may also be applied to uses other than vehicles.

[0017] The battery pack 11 is installed in the vehicle 10 as a driving power source of the vehicle 10. Figure 1 In the embodiment, the battery pack 11 is disposed in the engine room of the vehicle 10, but the present invention is not limited thereto. The battery pack 11 may be disposed in other places such as a trunk, under a seat, or under a floor. The vehicle 10 is an electric vehicle or a hybrid vehicle that runs using the power stored in the battery pack 11.

[0018] The battery pack 11 includes a battery pack 20, which includes a plurality of battery cells 22 (secondary single cells). In detail, a battery module 21 (sometimes also referred to as a battery stack or battery block) is formed by a plurality of battery cells 22 connected in series and / or in parallel, and a plurality of battery modules 21 are connected in series to form the battery pack 20. Each battery cell 22 is formed of a lithium-ion secondary battery or a nickel-metal hydride secondary battery. In addition, a lithium-ion secondary battery is a secondary battery using lithium as a charge carrier, and in addition to a general lithium-ion secondary battery in which the electrolyte is a liquid, it can also include a so-called all-solid battery using a solid electrolyte.

[0019] The battery pack 11 stores power for driving the motor 13 in the battery group 20 and can supply power to the motor 13 through the PCU 12. The battery pack 11 is charged by receiving power generated by the motor 13 through the PCU 12 when the motor 13 generates regenerative power, such as during vehicle braking.

[0020] In addition, the battery pack 11 is provided with a monitoring unit for monitoring the battery pack 20 and a control unit for receiving the monitoring result of the monitoring unit and executing a predetermined process. The configuration of the monitoring unit and the control unit will be described in detail below. Figure 2 The details will be described later.

[0021] The PCU 12 performs bidirectional power conversion between the battery pack 11 and the motor 13 according to a control signal from the vehicle ECU 14. For example, the PCU 12 includes an inverter for driving the motor 13 and a converter for boosting the DC voltage supplied to the inverter to a voltage higher than the output voltage of the battery pack 11.

[0022] The motor 13 is an AC rotating electric machine, for example, a three-phase AC synchronous motor with a permanent magnet embedded in the rotor. The motor 13 is driven by the PCU 12 to generate a rotational driving force, and the driving force generated by the motor 13 is transmitted to the drive wheels. On the other hand, when the vehicle 10 brakes, the motor 13 acts as a generator and regenerates electricity. The electricity generated by the motor 13 is supplied to the battery pack 11 through the PCU 12 and stored in the battery pack 20 in the battery pack 11.

[0023] The vehicle ECU 14 is configured to include a CPU, a ROM, a RAM, an input / output port for inputting and outputting various signals, etc. The CPU expands and executes the program stored in the ROM in the RAM. The processing of the vehicle ECU 14 is recorded in the program stored in the ROM. As an example of the main processing of the vehicle ECU 14, the vehicle ECU 14 receives information such as the voltage, current, and SOC (State Of Charge) of the battery pack 20 from the battery pack 11, and controls the driving of the motor 13 and the charging and discharging of the battery pack 11 by controlling the PCU 12.

[0024] <Structure of battery pack 11> Figure 2 1 is a perspective view schematically showing the interior of the battery pack 11. The battery pack 11 includes a battery group 20, a plurality of battery monitoring devices 30, a battery control device 40, and a housing 50 for housing them. A connector 58 for connecting the battery pack 11 to an external device is provided on the side of the housing 50. Figure 2 As shown, among the surfaces of the rectangular parallelepiped housing 50, the surface ( Figure 2 In the embodiment, the left-right direction of the vehicle 10 corresponds to the X direction, the front-back direction corresponds to the Y direction, and the up-down direction corresponds to the Z direction, but the battery pack 11 may be arranged in any manner relative to the vehicle 10.

[0025] <Structure of battery pack 20> The battery pack 20 includes a plurality of battery modules 21 arranged in the X direction. The battery pack 20 is formed by connecting the plurality of battery modules 21 in series. Each battery module 21 includes a plurality of battery cells 22 arranged in the Y direction. The battery module 21 is formed by connecting the plurality of battery cells 22 in series.

[0026] Linear bus bar units 23 are provided at both ends in the X direction on the upper surface of each battery module 21 . The bus bar units 23 electrically connect the battery cells 22 .

[0027] <Configuration of Battery Monitoring Device 30 > The battery monitoring device 30 is also called a satellite battery module (SBM), and is provided for each battery module 21. Figure 2 As shown, it is provided between the busbar units 23 disposed at both ends of each battery module 21. Figure 3 As shown, each battery monitoring device 30 includes a monitoring IC 31 as a monitoring unit, a wireless IC 32 as a monitoring side wireless unit, a wireless antenna 34, etc. The monitoring IC 31 is also called a cell monitoring circuit (CSC), and obtains battery information from each battery cell 22 constituting the battery module 21. The battery information includes, for example, voltage information, temperature information, current information, self-diagnosis information, etc. of each battery cell 22. The self-diagnosis information is, for example, information related to the operation confirmation of the battery monitoring device 30, that is, information related to the abnormality or failure of the battery monitoring device 30. Specifically, it is information related to the operation confirmation of the monitoring IC 31, the wireless IC 32, etc. constituting the battery monitoring device 30.

[0028] The wireless IC 32 is connected to the monitoring IC 31 by wire, and is a microcomputer having a communication interface 321, a CPU 322, and a counter 323. Figure 3 In the figure, ROM, RAM, etc. are omitted due to space constraints, but the wireless IC 32 also has ROM, RAM, etc. Figure 3 The same is true for the following drawings. The monitoring IC 31 includes a communication interface 311. The wireless IC 32 and the monitoring IC 31 exchange data via the communication interface. The wireless IC 32 transmits the data received from the monitoring IC 31 to the battery control device 40 via the wireless antenna 34. In addition, the wireless IC 32 transmits the data received via the wireless antenna 34 to the monitoring IC 31. The counter 323 is a logic circuit that counts the number of on / off signals input from an input device such as a switch or a sensor or measures time.

[0029] The wireless IC 32 is connected to the battery cell 22 via the power supply circuit 33. The wireless IC 32 operates by power supplied from the battery cell 22 via the power supply circuit 33.

[0030] <Configuration of Battery Control Device 40 > The battery control device 40 is also called a battery ECU or a BMU (Battery Management Unit), and is mounted on the outer side surface of the battery module 21 arranged at one end in the X direction. The battery control device 40 is configured to be able to communicate wirelessly with each battery monitoring device 30 .

[0031] Describe in detail, such as Figure 3 As shown in FIG. 4 , the battery control device 40 includes a control MCU 41 as a control unit, a wireless IC 42 as a control-side wireless unit, a wireless antenna 43, and the like. The control MCU 41 is a microcomputer having a communication interface 411 and a CPU 412. As with the wireless IC 32, the control MCU 41 is also not shown in the figure for ROM, RAM, and the like, but the control MCU 41 also has ROM, RAM, and the like. The CPU 412 expands the program stored in the ROM in the RAM and executes it. The program stored in the ROM records the processing related to the battery control.

[0032] As an example of the main processing, the control MCU 41 instructs the battery monitoring device 30 to obtain and send battery information. In addition, the control MCU 41 monitors the battery pack 20, the battery module 21, and the battery cell 22 based on the battery information received from the battery monitoring device 30. In addition, the control MCU 41 controls the relay switch that switches the energization and de-energization state of the battery pack 20 and the PCU 12 or the motor 13 based on the monitoring results. In addition, the control MCU 41 sends a voltage equalization instruction signal. The voltage equalization instruction signal will be described later. In addition, in the present embodiment, the vehicle ECU 14 instructs the PCU 12 to perform the charge and discharge control of the battery pack 20, but it can also be configured to be able to implement the control MCU 41.

[0033] The wireless IC 42 is connected to the control MCU 41 by wire, and is a microcomputer having a communication interface 421 and a CPU 422, similarly to the wireless IC 32. As for the wireless IC 42, although the ROM, RAM, etc. are omitted from the illustration, the wireless IC 42 also has the ROM, RAM, etc. The wireless IC 42 transmits the data received from the control MCU 41 to the battery monitoring device 30 via the wireless antenna 43. In addition, the wireless IC 42 transmits the data received via the wireless antenna 43 to the control MCU 41.

[0034] In the present embodiment, the battery control device 40 is described as exchanging data with the battery monitoring device 30 by wireless communication, but the present invention is not limited thereto. The battery control device 40 and the battery monitoring device 30 may be connected by wire. Figure 3Reference numeral 60 is a load to which electric power is supplied from the battery pack 11 , and an example thereof is the above-mentioned electric motor 13 .

[0035] Next, consider using Figure 2-Figure 3 The battery pack 11 is described as being removed from the vehicle 10. One example of the purpose of removing the battery pack 11 from the vehicle 10 is for so-called 3R. 3R is a general term for Reduce, Reuse, and Recycle. Figure 4 1 shows the state after the battery pack 11 is removed from the vehicle 10. In this embodiment, the "state in which the battery pack 11 is removed from the vehicle 10" means that the battery pack 11 itself is removed from the vehicle 10, but the battery modules 21 constituting the battery pack 11 are not disassembled. Figure 4 As shown, the battery pack 11 is separated from the load 60 , but the structure of the battery pack 11 is not changed.

[0036] When the battery pack 11 is reused, the battery pack 11 itself may be reused or the battery modules 21 constituting the battery pack 11 may be reused. When the battery modules 21 constituting the battery pack 11 are reused, the battery modules 21 need to be removed from the battery pack 11. Figure 5 The figure shows a state in which one battery module 21 among a plurality of battery modules is removed from the battery pack 11. Hereinafter, such a state is referred to as "a state in which the battery module 21 is removed from the battery pack 11". When the battery module 21 is removed from the battery pack 11, the battery pack 11 may be removed from the vehicle 10 or may remain installed in the vehicle 10. In addition, when only one battery module 21 remains in the battery pack 11, the state in which the last battery module 21 is removed is also equivalent to "a state in which the battery module 21 is removed from the battery pack 11".

[0037] Next, refer to Figure 6, an example of a method for determining whether the battery pack 11 is removed from the vehicle 10 is described. As described above, the battery monitoring device 30 (wireless IC 32) and the battery control device 40 periodically exchange data through wireless communication. When the start instruction signal or the voltage equalization instruction signal of the battery cell 22 is not input from the battery control device 40 within a certain period (T1), the wireless IC 32 determines that the communication with the battery control device 40 is disconnected. The "start instruction signal" is a signal input when the ignition switch of the vehicle 10 is turned on. The "voltage equalization instruction signal" is a signal input when the voltage of the battery cell 22 is equalized. Regarding the voltage equalization instruction signal, even if the ignition switch is turned off, it is sent from the battery control device 40 to the wireless IC 32 at regular intervals (T2) (T1>T2). Therefore, at least for the voltage equalization instruction signal, as long as the battery pack 11 is installed in the vehicle 10, the wireless IC 32 receives it at regular intervals (T2). On the other hand, when the battery pack 11 is removed from the vehicle 10 , neither the start-up instruction signal nor the voltage equalization instruction signal is transmitted from the battery control device 40 to the wireless IC 32 .

[0038] That is, the fact that these signals are not input within a certain period (T1) means that the battery pack 11 is not installed in the vehicle 10 or is highly likely not installed in the vehicle 10. Therefore, when the predetermined signal is not input within a certain period, the wireless IC 32 determines that the communication with the battery control device 40 is disconnected. Then, when the wireless IC 32 determines that the communication with the battery control device 40 is disconnected, it determines that the battery pack 11 is removed from the vehicle 10. Such a function of the wireless IC 32 (the function of the CPU 322 of the wireless IC 32) corresponds to the "determination unit".

[0039] As other judgment methods, such as Figure 6 As shown, a signal from an external device 70 may also be used. An example of the external device 70 is an inspection device used when inspecting a vehicle. When the wireless IC 32 receives a signal notifying that communication is disconnected from such an external device 70 via the wireless antenna 72, the wireless IC 32 may determine that communication with the battery control device 40 is disconnected.

[0040] In addition, Figure 6 In the above description, a method for determining whether the battery pack 11 is removed from the vehicle 10 is described. However, “whether the battery module 21 is removed from the battery pack 11” can also be determined by the same method.

[0041] Next, refer to Figure 7 , the processing after determining that the battery module 21 is removed from the battery pack 11 is described. Figure 7In the above description, it is assumed that the battery pack 11 is mounted on the vehicle 10 before the battery module 21 is removed from the battery pack 11. When it is determined that the battery module 21 is removed from the battery pack 11, the battery monitoring device 30 (wireless IC 32) implements a function that is not implemented when the battery module 21 is installed in the battery pack 11. "The function that is not implemented when the battery module 21 is installed in the battery pack 11" refers to the function implemented by the battery control device 40 when the battery module 21 is installed in the battery pack 11. That is, when it is determined that the battery module 21 is removed from the battery pack 11, the wireless IC 32 replaces the battery control device 40 to implement the function that the battery control device 40 implements when the battery module 21 is installed in the battery pack 11. The function that the wireless IC 32 implements instead may be all the functions implemented by the battery control device 40 or a part of the functions. Here, the function that the wireless IC 32 implements instead is a part of the function implemented by the battery control device 40. The purpose of the wireless IC 32 when it is implemented instead is different from the original purpose. This will be described later.

[0042] When the battery module 21 is installed in the battery pack 11, one of the functions implemented by the battery control device 40 is the transmission of the voltage equalization instruction signal. The voltage equalization instruction signal is a signal sent by the battery control device 40 to the battery monitoring device 30 (wireless IC 32) in order to equalize the voltage of each battery cell 22. The signal is further sent from the wireless IC 32 to the monitoring IC 31. The monitoring IC 31 drives the voltage equalization circuit 80 to equalize the voltage of each battery cell 22. The voltage equalization circuit 80 is a circuit that uses the battery cell 22 as a power source and outputs a specified current.

[0043] After determining that the battery module 21 is removed from the battery pack 11, the wireless IC 32 implements the transmission of the voltage equalization instruction signal implemented by the battery control device 40 before the removal. Specifically, the wireless IC 32 transmits the voltage equalization instruction signal to the monitoring IC 31. Here, the battery control device 40 transmits the voltage equalization instruction signal for the purpose of equalizing the voltages of the battery cells 22. As described above, the purpose of the wireless IC 32 transmitting the voltage equalization instruction signal is different from its original purpose. That is, the purpose of the wireless IC 32 transmitting the voltage equalization instruction signal is not to equalize the voltages of the battery cells 22. The purpose of the wireless IC 32 transmitting the voltage equalization instruction signal is to measure the parameters used in the calculation of the SOH of each battery cell 22. Therefore, the wireless IC 32 transmits the voltage equalization instruction signal to the monitoring IC 31 to drive all the voltage equalization circuits 80 connected to each battery cell 22.

[0044] like Figure 7As shown, the monitoring IC 31 drives the voltage balancing circuit 80 according to the instruction. The monitoring IC 31 measures at least one of the current flowing in the voltage balancing circuit 80 and the voltage applied to the voltage balancing circuit 80. Of course, the monitoring IC 31 can measure both the current and the voltage, and can also measure the temperature at this time. As an example, a unit thermistor can be used for temperature measurement.

[0045] The monitoring IC 31 transmits the measured current and the like to the wireless IC 32. The wireless IC 32 calculates the battery state of the battery cell 22 using the current and the like obtained from the monitoring IC 31. In the present embodiment, the "battery state of the battery cell 22" refers to the SOH (State Of Health) of the battery cell 22. SOH is sometimes also referred to as a healthy state, a degraded state, etc. An example of a method for calculating SOH is described. Generally speaking, two indicators of capacity maintenance rate and internal resistance increase rate are known as SOH. "Capacity maintenance rate" refers to the ratio of the current full capacity of the battery to the full capacity of a new battery. "Internal resistance increase rate" refers to the increase rate of the internal resistance that increases as the battery deteriorates. The physical quantities that can be measured from the outside of the battery are current, voltage, and temperature, and it is difficult to directly measure SOH. Therefore, methods such as OCV estimation method (Open Circuit Voltage: open circuit voltage) and nonlinear Kalman filter are known. The wireless IC 32 calculates SOH using these methods. In addition to the above two indicators, there are also known methods for calculating SOH using SOC or the internal resistance of the battery, so the wireless IC 32 can also calculate SOH using these. In addition, when the battery module 21 is removed from the battery pack 11, the wireless IC 32 drives the battery cell 22 as a power source.

[0046] Thus, according to the present embodiment, after determining that the battery module 21 is removed from the battery pack 11, the wireless IC 32 discharges the battery cell 22 at a predetermined time to calculate the SOH. As described above, in the prior art, since charging and discharging are not performed after removal, the SOH after removal cannot be determined. In contrast, in the present embodiment, since the battery cell 22 is discharged to calculate the SOH, the SOH after removal can be determined.

[0047] In addition, in the present embodiment, after determining that the battery module 21 is removed from the battery pack 11, the wireless IC 32 transmits the voltage equalization instruction signal that was implemented by the battery control device 40 before the removal. The battery control device 40 transmits the voltage equalization instruction signal for the purpose of equalizing the voltages of the battery cells 22, but the wireless IC 32 transmits the voltage equalization instruction signal for a different purpose, which is to measure the parameters used in the calculation of SOH. That is, in the present embodiment, the wireless IC 32 uses the function implemented by the battery control device 40 for a purpose different from the original purpose. By using such an existing function for a different purpose, there is no need to add new functions, devices, etc., which helps to reduce costs.

[0048] exist Figure 7 In the embodiment, the function implemented by the battery control device 40 before the battery module 21 is removed from the battery pack 11 is exemplified as the transmission of the voltage balancing instruction signal, but the present invention is not limited thereto. In short, as long as the current can be taken out from the battery cell 22, for example, Figure 8 As shown, the wireless IC 32 replaces the function of sending a drive signal to the module balancing circuit 81. In addition, the battery control device 40 also has a function of driving a circuit for adjusting the temperature state of the battery cell 22, a circuit for measuring the impedance of the battery cell 22, etc., but the wireless IC 32 can also replace these functions. In addition, as described above, the purpose of the wireless IC 32 driving these circuits is different from the original purpose, but is to measure the parameters used in the calculation of SOH. The voltage balancing circuit 80 and the module balancing circuit 81 are described as circuits provided in the battery monitoring device 30, but are not limited to this.

[0049] Next, refer to Fig. 9 An operation example of the battery monitoring device 30 (wireless IC 32 and monitoring IC 31) is described with reference to the flowchart. Fig. 9 The shown processing is repeatedly executed at predetermined time intervals.

[0050] In step S101, after determining that the battery module 21 is removed from the battery pack 11, the wireless IC 32 transmits the voltage equalization instruction signal implemented by the battery control device 40 before the removal at a predetermined time. This drives the voltage equalization circuit 80. The predetermined time is set in advance by experiments, simulations, etc.

[0051] The process proceeds to step S102, and the monitoring IC 31 measures at least one of the current flowing in the voltage equalization circuit 80 and the voltage applied to the voltage equalization circuit 80. The process of step S102 is repeatedly executed until the predetermined time has passed (step S103). The predetermined time is measured by the counter 323. After the predetermined time has passed, the process proceeds to step S104, and the wireless IC 32 stops the voltage equalization circuit 80. Since the purpose of driving the voltage equalization circuit 80 is to measure the current, etc., if the measurement of the current, etc. is completed, there is no reason to drive the voltage equalization circuit 80. The process proceeds to step S105, and the wireless IC 32 calculates the SOH of the battery cell 22 using the measured current, etc., and stores the calculation result in its own storage unit (for example, a memory). The calculation result of the SOH can be stored as the calculation value itself or in the form of a histogram.

[0052] The timing for reading the calculation result of the SOH stored in the storage unit is not particularly limited, and one example is when the battery module 21 is mounted on the battery pack 11 .

[0053] According to the first embodiment described in detail above, the following effects can be obtained.

[0054] The battery pack 11 or the battery module 21 is configured to be replaceable with respect to the motor 13. The battery pack 11 or the battery module 21 includes: a battery cell 22 that can supply power to the motor 13 when the battery pack 11 or the battery module 21 is mounted on the motor 13; a voltage balancing circuit 80 that is connected to the battery cell 22; a monitoring IC 31 that measures at least one of a current flowing through the voltage balancing circuit 80 and a voltage applied to a load unit; and a wireless IC 32 that operates the battery cell 22 as a power source when the battery pack 11 or the battery module 21 is removed from the motor 13, flows a current from the battery cell 22 to the voltage balancing circuit 80 at a predetermined timing, and acquires a measurement result measured by the monitoring IC 31 at this time. The motor 13 corresponds to an "external load". The battery cell 22 corresponds to a "battery unit". The voltage balancing circuit 80 corresponds to a "load unit". The monitoring IC 31 corresponds to a "measurement unit". The wireless IC 32 corresponds to a "control unit".

[0055] According to the present embodiment, the battery pack 11 or the battery module 21 discharges the battery cell 22 at a predetermined time to measure the current, etc. The measured current, etc. can be used, for example, for calculating the SOH. As described above, in the prior art, since charging and discharging are not performed after removal, the SOH after removal cannot be grasped. In contrast, in the present embodiment, since the battery cell 22 is discharged to calculate the SOH, the SOH after removal can be grasped.

[0056] In the present embodiment, the case where the SOH of the battery cells 22 constituting the battery module 21 is calculated mainly in the state where the battery module 21 is removed from the battery pack 11 is described, but the present invention is not limited to this. Figure 4 As shown, the SOH of the battery cells 22 constituting the battery pack 11 may also be calculated in the state where the battery pack 11 is removed from the vehicle 10. In addition, in recent years, there have been methods of directly mounting battery cells on the battery pack without constituting a battery module, methods of integrating the housing portion of the battery pack with the vehicle body and directly housing the battery module in the vehicle body, and methods of directly housing the battery cells in the vehicle body.

[0057] Therefore, the present embodiment may also calculate the SOH of the battery cell 22 in a state where the battery cell 22 directly mounted on the vehicle 10 is removed from the vehicle 10. In this case, the battery monitoring device 30 is mounted on the battery cell 22. In addition, the SOH of the battery cell 22 constituting the battery module 21 may be calculated in a state where the battery module 21 directly mounted on the vehicle 10 is removed from the vehicle 10. That is, the "battery unit" includes a "battery pack equipped with a battery monitoring device 30", a "battery module equipped with a battery monitoring device 30", or a "battery cell equipped with a battery monitoring device 30".

[0058] Furthermore, the wireless IC 32 may calculate and store the SOH of the battery cell 22 based on the measurement result measured by the monitoring IC 31 when the battery pack 11 or the battery module 21 is removed from the motor 13. This allows the SOH after removal to be understood.

[0059] In addition, the wireless IC 32 notifies the battery control device 40 of the measurement result measured by the monitoring IC 31 in accordance with the instruction from the battery control device 40 communicating with the wireless IC 32 when the battery pack 11 or the battery module 21 is mounted on the motor 13. On the other hand, the wireless IC 32 performs the calculation of SOH, which was not performed when the battery pack 11 or the battery module 21 was mounted on the motor 13, when the battery pack 11 or the battery module 21 is removed from the motor 13. The calculation of SOH, which was performed by the battery control device 40 before the battery pack 11 or the battery module 21 was removed, is performed by the wireless IC 32 when the battery pack 11 or the battery module 21 is removed. Thus, the calculation of SOH can be performed without adding new functions, devices, etc.

[0060] The wireless IC 32 determines whether the communication with the battery control device 40 is disconnected. When the wireless IC 32 determines that the communication with the battery control device 40 is disconnected, it determines that the battery pack 11 or the battery module 21 is removed from the motor 13, and uses this as an opportunity to flow current from the battery cell 22 to the voltage balancing circuit 80. In this way, the SOH can be calculated at an appropriate time.

[0061] The wireless IC 32 determines that the communication with the battery control device 40 is disconnected when no start-up instruction signal or battery cell 22 voltage equalization instruction signal is input from the battery control device 40 for a certain period of time, or when a signal notifying that the communication is disconnected is input from the external device 70. In this way, by using the signal transmitted from the battery control device 40 or the external device 70, it is possible to appropriately determine whether the communication is disconnected.

[0062] The “load part” includes Figure 7-8 The circuit for equalizing the voltage described above (voltage equalization circuit 80, module equalization circuit 81). In addition, the "load unit" may also include a load for adjusting the temperature state of the battery cell 22. An example of the "load for adjusting the temperature state of the battery cell 22" is a heater built into the battery pack 11 and used to heat the battery cell 22. In addition, the "load unit" may also include a load for passing a current when measuring the impedance of the battery cell 22. By using such an existing load, it is possible to perform the SOH calculation without adding new functions, devices, etc.

[0063] <Second embodiment> Next, refer to Fig.10In the first embodiment, the voltage balancing circuit 80 is driven for a different purpose to discharge the battery cells 22 to calculate the SOH, but in the second embodiment, the SOH is calculated using the change in the self-discharge rate of the battery cells 22 .

[0064] exist Fig.10 In step S201 shown, after determining that the battery module 21 is removed from the battery pack 11, the wireless IC 32 waits until a prescribed time has passed. After the prescribed time has passed ("Yes" in step S201), the process proceeds to step S202, and the wireless IC 32 turns on a flag related to self-discharge. In addition, the wireless IC 32 may turn on a flag related to self-discharge based on an instruction from the external device 70. The process proceeds to step S203, and the wireless IC 32 stops functions other than the counter 323. The reason for stopping functions other than the counter 323 is to prevent currents other than the current caused by self-discharge from flowing through the circuit. The process proceeds to step S204, and the process waits for a prescribed time (to allow the battery cell 22 to self-discharge) in a state where functions other than the counter 323 are stopped.

[0065] After the prescribed time has passed ("Yes" in step S204), the process proceeds to step S205, and the wireless IC 32 resumes the stopped function. The process proceeds to step S206, and the wireless IC 32 calculates the transition of the self-discharge rate of the battery cell 22. As an example of a method for calculating the transition of the self-discharge rate, a method of calculating based on the remaining capacity (SOC) of the battery cell 22 at the beginning of the prescribed time in step S204 and the change rate of the remaining capacity (SOC) of the battery cell 22 at the end of the prescribed time can be cited. The remaining capacity can be calculated using the voltage, current, temperature, etc. of the battery cell 22. The wireless IC 32 calculates the SOH based on the transition of the self-discharge rate of the battery cell 22.

[0066] According to the second embodiment, the following effects can be obtained.

[0067] The battery pack 11 or the battery module 21 includes a wireless IC 32, and the wireless IC 32 is configured to operate the battery cell 22 as a power source and calculate the change of the self-discharge rate of the battery cell 22 when the battery pack 11 or the battery module 21 is removed from the motor 13. The calculated change of the self-discharge rate can be used, for example, for calculating the SOH. Since the change of the self-discharge rate can be calculated without adding new functions, devices, etc., it helps to reduce the cost when calculating the SOH.

[0068] The wireless IC 32 stops functions other than the counter 323 that measures the time related to self-discharge for a predetermined time. This prevents current other than the current caused by self-discharge from flowing through the circuit, and improves the calculation accuracy of the transition of the self-discharge rate. The wireless IC 32 calculates the transition of the self-discharge rate based on the remaining capacity of the battery cell 22 at the beginning of the predetermined time and the change rate of the remaining capacity of the battery cell 22 at the end of the predetermined time. Then, the wireless IC 32 calculates the SOH of the battery cell 22 based on the calculated transition of the self-discharge rate and stores it.

[0069] <Other embodiments> In the above embodiment, the wireless IC 32 stores the calculation result of the SOH in its own storage unit, but the present invention is not limited to this. Fig.11 As shown, the wireless IC 32 may also use wireless communication to send the calculation result of SOH to the external device 70 (e.g., a cloud server). By using wireless communication, a physical interface such as a connector is not required. In addition, in the above embodiment, the wireless IC 32 uses the measured current, etc. to calculate SOH, but this is not limited to this. Fig.11 As shown, the wireless IC 32 may transmit the measured current, etc. to the external device 70, and the external device 70 may perform the calculation of SOH. In this case, the wireless IC 32 may have a function of storing the measured current, etc. and a function of transmitting. In addition, both the wireless IC 32 and the external device 70 may calculate SOH. In this case, the calculation results of both may be combined to compare the validity of the calculation results. In the case where the calculation results are different, the difference may be used as a correction coefficient in the next calculation.

[0070] ·like Fig.12 As shown, in addition to the battery module 21 of the present embodiment, when there are battery modules 90 to 92 that are different in style and specification from the battery module 21, the SOH calculated by these battery modules can also be sent to the external device 70. Such sending is achieved by, for example, unifying the communication frequency. In this way, it is possible to uniformly manage battery modules of different styles and specifications.

[0071] When the power storage state of the battery cell 22 is equal to or less than a certain value, the wireless IC 32 may stop the current from the battery cell 22 to the load unit. This can suppress overdischarge of the battery cell 22 .

[0072] Regarding the operating frequency of the monitoring IC 31, the operating frequency may be lower after the battery pack 11 is removed from the vehicle 10 compared to before the battery pack 11 is removed from the vehicle 10. One of the functions of the monitoring IC 31 includes fault diagnosis, but the number of fault diagnoses may be reduced after the battery pack 11 is removed from the vehicle 10 compared to before the battery pack 11 is removed from the vehicle 10. This is because the need for fault diagnosis is lower after the battery pack 11 is removed from the vehicle 10.

[0073] As a signal for causing the wireless IC 32 to drive the voltage equalization circuit 80, the module equalization circuit 81, etc., a dedicated signal may be used instead of the signal used by the battery control device 40. That is, the signal is not limited as long as it can drive the voltage equalization circuit 80, etc.

[0074] The control unit and the method of the control unit described in the present disclosure may also be implemented by a special-purpose computer, which is provided by constituting a processor and a memory, and the above-mentioned processor is programmed to perform one or more functions embodied by a computer program. Alternatively, the control unit and the method thereof described in the present disclosure may be implemented by a special-purpose computer, which is provided by constituting a processor composed of one or more special-purpose hardware logic circuits. Alternatively, the control unit and the method thereof described in the present disclosure may be implemented by one or more special-purpose computers, which are constituted by a combination of a processor and a memory programmed to perform one or more functions and a processor constituted by one or more hardware logic circuits. In addition, the computer program may also be stored in a computer-readable non-temporary tangible storage medium as an instruction executed by a computer.

[0075] Hereinafter, characteristic structures extracted from the above-mentioned embodiments will be described. [Structure 1] A battery cell, The battery unit (11, 21, 22) is configured to be replaceable relative to an external load (13), and the battery unit includes: a battery unit (22) capable of supplying electric power to the external load when the battery unit is mounted on the external load; A load unit (80), the load unit being connected to the battery unit; a measuring unit (31) for measuring at least one of a current flowing in the load unit and a voltage applied to the load unit; and A control unit (32) is configured to operate the battery unit as a power source when the battery unit is removed from the external load, and to cause current to flow from the battery unit to the load unit at a predetermined time, and to obtain a measurement result measured by the measurement unit at this time. [Structure 2] According to the battery unit described in Configuration 1, the control unit calculates and stores the battery state of the battery unit based on the measurement result in a state where the battery unit is detached from the external load. [Structure 3] A battery cell according to structure 1 or 2, wherein: The control unit notifies the battery control unit of the measurement result in accordance with an instruction from a battery control unit communicating with the control unit in a state where the battery unit is mounted on the external load. On the other hand, in a state where the battery unit is detached from the external load, the calculation of the battery state which is not performed in a state where the battery unit is attached to the external load is performed. [Structure 4] According to the battery cell described in Structure 3, further comprising a determination unit configured to determine whether the communication between the control unit and the battery control device is disconnected, When the determination unit determines that the communication with the battery control device is disconnected, the control unit determines that the battery unit is detached from the external load, and uses this as an opportunity to flow current from the battery unit to the load unit and measure the current in the measurement unit. [Structure 5] According to the battery unit described in structure 4, the above-mentioned determination unit determines that the communication with the above-mentioned battery control device is cut off when no start-up instruction signal or the voltage balancing instruction signal of the above-mentioned battery unit is input from the above-mentioned battery control device within a certain period of time, or when a signal notifying that the communication from the external device is cut off is input. [Structure 6] A battery cell according to any one of structures 1 to 5, wherein the load unit is any one of a load for equalizing the voltage of the battery unit, a load for adjusting the temperature state of the battery unit, or a load for passing a current when measuring the impedance of the battery unit. [Structure 7] According to the battery unit described in Configuration 5, the control unit is configured to be able to perform wireless communication with the external device. [Structure 8] The battery unit according to any one of Configurations 1 to 7, wherein the control unit stops the flow of current from the battery unit to the load unit when the power storage state of the battery unit is equal to or less than a certain value. [Structure 9] A battery unit, wherein the battery unit (11, 21, 22) is configured to be replaceable relative to an external load (13), and the battery unit comprises: a battery unit (22) capable of supplying electric power to the external load when the battery unit is mounted on the external load; and A control unit (32) is configured to operate the battery unit as a power source and calculate a change in the self-discharge rate of the battery unit when the battery unit is detached from the external load. [Structure 10] According to the battery cell described in structure 9, The control unit stops functions other than the counter for measuring the time associated with self-discharge for a predetermined time. The change in the self-discharge rate is calculated based on a rate of change between the remaining capacity of the battery unit at the beginning of the predetermined time and the remaining capacity of the battery unit at the end of the predetermined time, The battery state of the battery unit is calculated based on the calculated change in the self-discharge rate and is stored. [Structure 11] A battery monitoring device, wherein the battery monitoring device (30) is installed on a battery unit (11, 21, 22), the battery unit is configured to be replaceable relative to an external load (13), and the battery monitoring device comprises: a measuring unit (31) for measuring at least one of a current flowing in a load unit (80) connected to the battery unit (22) of the battery cell and a voltage applied to the load unit; and A control unit (32) is configured to operate the battery unit as a power source when the battery unit is removed from the external load, and to cause current to flow from the battery unit to the load unit at a predetermined time, and to obtain a measurement result measured by the measurement unit at this time.

[0076] Although the present disclosure is described based on the embodiments, it should be understood that the present disclosure is not limited to the above-mentioned embodiments and structures. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and methods, and other combinations and methods containing only one element, above or below them, also belong to the scope and thought range of the present disclosure.

Claims

1. A battery unit, wherein the battery unit (11, 21, 22) is configured to be replaceable relative to an external load (13), and the battery unit comprises: a battery unit (22) capable of supplying electric power to the external load when the battery unit is mounted relative to the external load; a load unit (80), the load unit being connected to the battery unit; a measuring unit (31) for measuring at least one of a current flowing through the load unit and a voltage applied to the load unit; and A control unit (32) is configured to operate the battery unit as a power source when the battery unit is removed from the external load, and to cause current to flow from the battery unit to the load unit at a predetermined time, and to obtain a measurement result measured by the measurement unit at this time.

2. The battery cell according to claim 1, wherein: The control unit calculates and stores the battery state of the battery unit based on the measurement result in a state where the battery unit is detached from the external load.

3. The battery cell according to claim 2, characterized in that the control unit notifying the battery control unit of the measurement result in accordance with an instruction from a battery control unit communicating with the control unit in a state where the battery unit is mounted on the external load, On the other hand, in a state where the battery unit is detached from the external load, calculation of the battery state that is not performed in a state where the battery unit is attached to the external load is performed.

4. The battery cell according to claim 3, characterized in that further comprising a determination unit that determines whether the communication between the control unit and the battery control device is disconnected, When the determination unit determines that the communication with the battery control device is disconnected, the control unit determines that the battery unit is detached from the external load, and uses this as an opportunity to flow current from the battery unit to the load unit and perform measurement in the measurement unit.

5. The battery cell according to claim 4, characterized in that The determination unit determines that communication with the battery control unit is disconnected when no startup instruction signal or a voltage equalization instruction signal for the battery unit is input from the battery control unit for a certain period of time, or when a signal notifying that communication is disconnected is input from an external device.

6. The battery cell according to claim 1, wherein: The load unit is any one of a load for equalizing the voltages of the battery units, a load for adjusting the temperature state of the battery units, and a load for passing a current when measuring the impedance of the battery units.

7. The battery cell according to claim 5, characterized in that The control unit is configured to be capable of wireless communication with the external device.

8. The battery cell according to any one of claims 1 to 7, characterized in that: The control unit stops the flow of current from the battery unit to the load unit when the power storage state of the battery unit is equal to or less than a certain value.

9. A battery unit, wherein the battery unit (11, 21, 22) is configured to be replaceable relative to an external load (13), and the battery unit comprises: a battery unit (22) capable of supplying electric power to the external load when the battery unit is mounted relative to the external load; as well as A control unit (32) is configured to operate the battery unit as a power source and calculate a change in a self-discharge rate of the battery unit when the battery unit is detached from the external load.

10. The battery cell according to claim 9, characterized in that The control unit stops functions other than the counter for measuring the time associated with self-discharge for a predetermined time. calculating the change in the self-discharge rate based on a rate of change between the remaining capacity of the battery unit at the beginning of the predetermined time and the remaining capacity of the battery unit at the end of the predetermined time, The battery state of the battery unit is calculated based on the calculated change in the self-discharge rate and is stored.

11. A battery monitoring device, the battery monitoring device (30) being mounted on a battery unit (11, 21, 22), the battery unit being configured to be replaceable relative to an external load (13), the battery monitoring device comprising: a measuring unit (31) for measuring at least one of a current flowing in a load unit (80) connected to a battery unit (22) of the battery cell and a voltage applied to the load unit; and A control unit (32) is configured to operate the battery unit as a power source when the battery unit is removed from the external load, and to cause current to flow from the battery unit to the load unit at a predetermined time, and to obtain a measurement result measured by the measurement unit at this time.

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