Battery unit and battery monitoring device

Abstract

To provide a battery unit and a battery monitoring device, which can grasp a battery state after a replaceable battery unit has been removed.SOLUTION: The battery unit includes: a battery portion (battery cell 22) that can supply an electric power to an external load in a state in which the battery unit is attached to the external load; a load portion (voltage equalization circuit 80) that is connected to the battery portion; a measurement portion (monitor IC31) that measures at least one of an electric current flowing through the load portion and a voltage applied to the load portion; and a control portion (radio IC32) that is configured to cause the battery portion to operate as an electric power source in a state in which the battery unit is detached from the external load, also causes the battery portion to pass an electric current to the load portion at a predetermined timing, and acquires a measurement result measured by the measurement portion at this time.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a battery unit and a battery monitoring device. [Background technology]

[0002] There are known inventions that grasp the degree of deterioration of each battery cell that constitutes a battery module after the battery module is removed from the battery pack. For example, the invention described in Patent Document 1 calculates the degree of deterioration before the battery module is removed from the battery pack and transmits the calculated degree of deterioration to an external device. Then, after the battery module is removed from the battery pack, the external device is referenced. This makes it possible to grasp the degree of deterioration of the battery cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-163650 Summary of the Invention [Problem to be solved by the invention]

[0004] After a battery module is removed from a battery pack, the storage environment of the battery module is not uniform. Depending on the storage environment, deterioration of the battery cells that make up the battery module may progress. Therefore, there is a need to understand the degree of deterioration of the battery cells after the battery module is removed. However, the invention described in Patent Document 1 does not charge or discharge the battery module after it is removed, so it can only understand the degree of deterioration before removal, and cannot understand the degree of deterioration after removal.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a battery unit and a battery monitoring device that are capable of determining the battery state after a replaceable battery unit is removed. [Means for solving the problem]

[0006] The present invention provides A battery unit configured to be replaceable with respect to an external load, a battery section capable of supplying power to the external load when the battery unit is attached to the external load; a load section connected to the battery section; a measuring unit that measures at least one of a current flowing through the load unit and a voltage applied to the load unit; The device is characterized by comprising a control unit configured to operate using the battery unit as a power source when the battery unit is detached from the external load, and which causes current to flow from the battery unit to the load unit at a predetermined timing and acquires the measurement results measured by the measurement unit at that time.

[0007] The battery unit discharges the battery portion at a predetermined timing and measures the current, etc. The measured current, etc. can be used, for example, to calculate the battery state. As described above, in the conventional technology, the battery is not charged or discharged after removal, so the battery state after removal cannot be determined. In contrast, in the present invention, the battery portion is discharged and measurement results are obtained, so the battery state after removal can be determined.

[0008] The present invention provides A battery unit configured to be replaceable with respect to an external load, a battery section capable of supplying power to the external load when the battery unit is attached to the external load; The device is characterized by being configured to operate using the battery section as a power source when the battery unit is detached from the external load, and also comprising a control section that calculates the progress of the self-discharge rate of the battery section.

[0009] The calculated change in the self-discharge rate can be used, for example, to calculate the battery state. The change in the self-discharge rate can be calculated without adding any new functions or devices, which contributes to reducing the cost of calculating the battery state.

[0010] The present invention provides A battery monitoring device (30) mounted on a battery unit (11, 21, 22) configured to be replaceable with respect to an external load (13), a measuring section (31) that measures at least one of a current flowing through a load section (80) connected to a battery section (22) of the battery unit and a voltage applied to the load section; The device is characterized by comprising a control unit (32) configured to operate using the battery unit as a power source when the battery unit is detached from the external load, and which causes current to flow from the battery unit to the load unit at a predetermined timing and acquires the measurement results measured by the measurement unit at that time.

[0011] The battery monitoring device discharges the battery module at a predetermined timing and measures the current, etc. The measured current, etc. can be used, for example, to calculate the battery status. As described above, in the conventional technology, the battery module is not charged or discharged after removal, so the battery status after removal cannot be determined. In contrast, in the present invention, the battery module is discharged and measurement results are obtained, so the battery status after removal can be determined. [Brief explanation of the drawings]

[0012] [Figure 1] Vehicle configuration diagram. [Figure 2] FIG. [Figure 3] FIG. 2 is a block diagram showing a battery control device and a battery monitoring device. [Figure 4] FIG. 10 is a block diagram showing a state in which the battery pack is removed. [Figure 5] FIG. 4 is a block diagram showing a state in which a battery module is removed. [Figure 6]FIG. 10 is a block diagram for determining whether the battery pack has been removed. [Figure 7] FIG. 2 is a block diagram showing that a battery monitoring device performs part of the functions of the battery control device. [Figure 8] FIG. 2 is a block diagram showing that a battery monitoring device performs part of the functions of the battery control device. [Figure 9] 4 is a flowchart illustrating an example of the operation of the battery monitoring device according to the first embodiment. [Figure 10] 10 is a flowchart illustrating an example of the operation of the battery monitoring device according to the second embodiment. [Figure 11] FIG. 10 is a block diagram illustrating another embodiment. [Figure 12] FIG. 10 is a block diagram illustrating another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, the same parts are designated by the same reference numerals and the description thereof will be omitted.

[0014] First Embodiment An example of the configuration of a battery pack 11 mounted on a vehicle 10 will be described with reference to FIGS. <Overall configuration of vehicle 10> FIG. 1 is a diagram illustrating a schematic configuration of a vehicle 10. The vehicle 10 includes a battery pack 11 (referred to as "Battery" in FIG. 1), a power control unit (hereinafter referred to as "PCU (Power Control Unit)") 12, a motor 13 (referred to as "MG" in FIG. 1), and a vehicle ECU 14 (referred to as "ECU" in FIG. 1). Here, an embodiment in which the battery pack 11 is applied to the vehicle 10 will be described, but the battery pack 11 according to the present disclosure can also be applied to applications other than vehicles.

[0015] The battery pack 11 is mounted on the vehicle 10 as a driving power source for the vehicle 10. In FIG. 1, the battery pack 11 is installed in the engine compartment of the vehicle 10, but is not limited to this. The battery pack 11 may be installed in other locations, such as the trunk, under a seat, or under the floor. The vehicle 10 is an electric vehicle or a hybrid vehicle that runs using power stored in the battery pack 11.

[0016] The battery pack 11 includes an assembled battery 20 configured with a large number of battery cells 22 (secondary cells). More specifically, a battery module 21 (sometimes referred to as a battery stack or battery block) is configured with a plurality of battery cells 22 connected in series and / or parallel, and the assembled battery 20 is configured with a plurality of battery modules 21 connected in series. Each battery cell 22 is configured with a lithium-ion secondary battery, a nickel-metal hydride secondary battery, or the like. Note that a lithium-ion secondary battery is a secondary battery that uses lithium as a charge carrier, and may include not only a typical lithium-ion secondary battery with a liquid electrolyte, but also a so-called all-solid-state battery that uses a solid electrolyte.

[0017] The battery pack 11 stores power for driving the motor 13 in a battery assembly 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 power regeneratively, such as during vehicle braking.

[0018] The battery pack 11 is also provided with a monitoring unit that monitors the assembled battery 20 and a control unit that receives the monitoring results from the monitoring unit and executes predetermined processing. The configurations of the monitoring unit and the control unit will be described in detail with reference to FIG. 2 and subsequent figures.

[0019] The PCU 12 performs bidirectional power conversion between the battery pack 11 and the motor 13 in accordance with a control signal from the vehicle ECU 14. The PCU 12 includes, for example, an inverter that drives the motor 13 and a converter that boosts the DC voltage supplied to the inverter to a voltage equal to or higher than the output voltage of the battery pack 11.

[0020] The motor 13 is an AC rotating electric machine, such as 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 rotational driving force, which is transmitted to the drive wheels. Meanwhile, when braking the vehicle 10, the motor 13 operates as a generator and performs regenerative power generation. The electric power generated by the motor 13 is supplied to the battery pack 11 via the PCU 12 and stored in the battery pack 20 in the battery pack 11.

[0021] The vehicle ECU 14 is configured to include a CPU, ROM, RAM, input / output ports for inputting and outputting various signals, etc. The CPU loads a program stored in the ROM into the RAM and executes it. The program stored in the ROM describes the processing of the vehicle ECU 14. 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 PCU 12 to control the driving of the motor 13 and the charging and discharging of the battery pack 11.

[0022] <Configuration of battery pack 11> FIG. 2 is a perspective view schematically illustrating the interior of the battery pack 11. The battery pack 11 includes a battery pack 20, a plurality of battery monitoring devices 30, a battery control device 40, and a housing 50 that houses them. A connector 58 is provided on a side of the housing 50 for connecting the battery pack 11 to an external device. Hereinafter, as shown in FIG. 2, of the surfaces of the rectangular parallelepiped housing 50, the longitudinal direction of the installation surface (the bottom surface in FIG. 2) that is installed on the vehicle 10 is referred to as the X direction, and the lateral direction is referred to as the Y direction. Furthermore, the up-down direction perpendicular to the installation surface is referred to as the Z direction. In this embodiment, the left-right direction of the vehicle 10 corresponds to the X direction, the front-rear direction corresponds to the Y direction, and the up-down direction corresponds to the Z direction. However, the battery pack 11 may be disposed in any manner relative to the vehicle 10.

[0023] <Configuration of battery pack 20> The battery pack 20 has a plurality of battery modules 21 arranged side by side in the X direction. These battery modules 21 are connected in series to form the battery pack 20. Each battery module 21 has a plurality of battery cells 22 arranged side by side in the Y direction. These battery cells 22 are connected in series to form the battery module 21.

[0024] Linear busbar units 23 are provided on both ends in the X direction on the upper surface of each battery module 21. The busbar units 23 electrically connect the battery cells 22 together.

[0025] <Configuration of battery monitoring device 30> The battery monitoring device 30, also called a satellite battery module (SBM), is provided for each battery module 21. As shown in FIG. 2, it is installed between the busbar units 23 located at both ends of each battery module 21. As shown in FIG. 3, each battery monitoring device 30 includes a monitoring IC 31, which serves as a monitoring unit, a wireless IC 32, which serves as a monitoring wireless unit, and a wireless antenna 34. The monitoring IC 31, also called a cell supervising circuit (CSC), acquires battery information from each battery cell 22 constituting the battery module 21. This battery information includes, for example, voltage information, temperature information, current information, and self-diagnosis information for each battery cell 22. The self-diagnosis information is, for example, information related to the operation check of the battery monitoring device 30, i.e., information related to an abnormality or malfunction of the battery monitoring device 30. Specifically, the information is information related to the operation check of the monitoring IC 31, wireless IC 32, and other components constituting the battery monitoring device 30.

[0026] 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. Due to space limitations, ROM, RAM, etc. are omitted from FIG. 3 , but the wireless IC 32 also has ROM, RAM, etc. This is the same for FIG. 3 and subsequent drawings. The monitoring IC 31 has a communication interface 311. The wireless IC 32 and the monitoring IC 31 exchange data via the communication interface. The wireless IC 32 transmits data received from the monitoring IC 31 to the battery control device 40 via the wireless antenna 34. The wireless IC 32 also transmits 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 input devices such as switches and sensors, and measures time.

[0027] The wireless IC 32 is connected to the battery cell 22 via a power supply circuit 33. The wireless IC 32 operates using power supplied from the battery cell 22 via the power supply circuit 33.

[0028] <Configuration of battery control device 40> The battery control device 40, also called a battery ECU or BMU (Battery Management Unit), is attached to the outer side surface of the battery module 21 located at one end in the X direction. The battery control device 40 is configured to be able to wirelessly communicate with each battery monitoring device 30.

[0029] 3, the battery control device 40 includes a control MCU 41, which is a control unit, a wireless IC 42, which is a control-side wireless unit, and a wireless antenna 43. The control MCU 41 is a microcomputer having a communication interface 411 and a CPU 412. As with the wireless IC 32, the ROM, RAM, and other components of the control MCU 41 are not shown, but the control MCU 41 also includes a ROM, RAM, and other components. The CPU 412 loads a program stored in the ROM into the RAM and executes it. The program stored in the ROM describes processes related to battery control.

[0030] As an example of main processing, the controlling MCU 41 instructs the battery monitoring device 30 to acquire and transmit battery information. The controlling MCU 41 also monitors the assembled battery 20, battery modules 21, and battery cells 22 based on the battery information received from the battery monitoring device 30. The controlling MCU 41 also controls relay switches that switch between energized and de-energized states of the assembled battery 20, the PCU 12, and the motor 13 based on the monitoring results, etc. The controlling MCU 41 also transmits a voltage equalization instruction signal. This voltage equalization instruction signal will be described later. Note that in this embodiment, the vehicle ECU 14 issues instructions to the PCU 12 to control the charging and discharging of the assembled battery 20, but the controlling MCU 41 may be configured to be able to perform this.

[0031] The wireless IC 42 is connected to the controlling MCU 41 by wire, and, like the wireless IC 32, is a microcomputer having a communication interface 421 and a CPU 422. Although ROM, RAM, etc. are not shown for the wireless IC 42 as with the wireless IC 32, the wireless IC 42 also has ROM, RAM, etc. The wireless IC 42 transmits data received from the controlling MCU 41 to the battery monitoring device 30 via a wireless antenna 43. The wireless IC 42 also transmits data received via the wireless antenna 43 to the controlling MCU 41.

[0032] In this embodiment, the battery control device 40 is described as exchanging data with the battery monitoring device 30 via wireless communication, but this is not limited to this. The battery control device 40 and the battery monitoring device 30 may be connected by wire. Reference numeral 60 shown in Fig. 3 denotes a load to which power is supplied from the battery pack 11, and an example is the motor 13 described above.

[0033] Next, consider a state in which the battery pack 11 described with reference to FIGS. 2 and 3 is removed from the vehicle 10. One example of the purpose of removing the battery pack 11 from the vehicle 10 is to achieve the so-called 3Rs. 3R is a general term for Reduce, Reuse, and Recycle. FIG. 4 shows a state in which the battery pack 11 is removed from the vehicle 10. In this embodiment, "a state in which the battery pack 11 is removed from the vehicle 10" refers to a state in which the battery pack 11 itself has been removed from the vehicle 10, but the battery modules 21 that make up the battery pack 11 have not been disassembled. In other words, "a state in which the battery pack 11 is removed from the vehicle 10" refers to a state in which the battery pack 11 is disconnected from the load 60 as shown in FIG. 4, but no change has occurred in the configuration of the battery pack 11.

[0034] When recycling the battery pack 11, there are cases where the battery pack 11 itself is recycled and cases where the battery modules 21 that make up the battery pack 11 are recycled. When recycling the battery modules 21 that make up the battery pack 11, it is necessary to remove the battery module 21 from the battery pack 11. FIG. 5 shows a state in which one battery module 21 from among multiple battery modules has been removed from the battery pack 11. Hereinafter, this state will be referred to as "a state in which the battery module 21 has been removed from the battery pack 11." When removing the battery module 21 from the battery pack 11, the battery pack 11 may have been removed from the vehicle 10, or may remain mounted on the vehicle 10. Note that a state in which only one battery module 21 remains in the battery pack 11 and the last battery module 21 has been removed also falls under "a state in which the battery module 21 has been removed from the battery pack 11."

[0035] Next, referring to FIG. 6, an example of a method for determining whether the battery pack 11 has been removed from the vehicle 10 will be described. As described above, the battery monitoring device 30 (wireless IC 32) and the battery control device 40 periodically exchange data via wireless communication. If the wireless IC 32 does not receive a startup instruction signal or a voltage equalization instruction signal for the battery cells 22 from the battery control device 40 for a certain period (T1), the wireless IC 32 determines that communication with the battery control device 40 has been interrupted. The "startup instruction signal" is a signal that is received when the ignition switch of the vehicle 10 is turned on. The "voltage equalization instruction signal" is a signal that is received when equalizing the voltages of the battery cells 22. The voltage equalization instruction signal is transmitted from the battery control device 40 to the wireless IC 32 at regular intervals (T2) even when the ignition switch is off (T1>T2). Therefore, the wireless IC 32 receives at least the voltage equalization instruction signal at regular intervals (T2) as long as the battery pack 11 is mounted on the vehicle 10. On the other hand, when the battery pack 11 is removed from the vehicle 10, neither the activation instruction signal nor the voltage equalization instruction signal is transmitted from the battery control device 40 to the wireless IC 32.

[0036] That is, if these signals are not input for a certain period of time (T1), it means that the battery pack 11 is not mounted on the vehicle 10, or there is a high possibility that it is not mounted on the vehicle 10. Therefore, if a predetermined signal is not input for a certain period of time, the wireless IC 32 determines that communication with the battery control device 40 has been cut off. If the wireless IC 32 determines that communication with the battery control device 40 has been cut off, it determines that the battery pack 11 has been 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 a "determination unit."

[0037] As another determination method, a signal from an external device 70 may be used, as shown in Fig. 6. An example of the external device 70 is an inspection device used when inspecting a vehicle. When the wireless IC 32 receives a signal from such an external device 70 via a wireless antenna 72 notifying that communication has been interrupted, the wireless IC 32 may determine that communication with the battery control device 40 has been interrupted.

[0038] Although Figure 6 describes a method for determining whether or not the battery pack 11 has been removed from the vehicle 10, it is also possible to determine whether or not the battery module 21 has been removed from the battery pack 11 using a similar method.

[0039] Next, referring to FIG. 7, a process after it is determined that the battery module 21 has been removed from the battery pack 11 will be described. In FIG. 7, it is assumed that the battery pack 11 is attached to the vehicle 10 before the battery module 21 is removed from the battery pack 11. When it is determined that the battery module 21 has been removed from the battery pack 11, the battery monitoring device 30 (wireless IC 32) performs functions that were not performed when the battery module 21 was attached to the battery pack 11. "Functions that were not performed when the battery module 21 was attached to the battery pack 11" refers to functions that were performed by the battery control device 40 when the battery module 21 was attached to the battery pack 11. In other words, when it is determined that the battery module 21 has been removed from the battery pack 11, the wireless IC 32 performs, in place of the battery control device 40, the functions that were performed by the battery control device 40 when the battery module 21 was attached to the battery pack 11. The functions performed by the wireless IC 32 may be all or some of the functions that were performed by the battery control device 40. Here, the functions performed by the wireless IC 32 will be described as part of the functions performed by the battery control device 40. The purpose of the functions performed by the wireless IC 32 is different from the original purpose, as will be described later.

[0040] One of the functions performed by the battery control device 40 when the battery module 21 is attached to the battery pack 11 is the transmission of the voltage equalization instruction signal described above. The voltage equalization instruction signal is a signal that the battery control device 40 transmits to the battery monitoring device 30 (wireless IC 32) in order to equalize the voltages of the battery cells 22. This signal is then transmitted from the wireless IC 32 to the monitoring IC 31. The monitoring IC 31 drives the voltage equalization circuit 80 to equalize the voltages of the battery cells 22. The voltage equalization circuit 80 is a circuit that uses the battery cells 22 as a power source and outputs a predetermined current.

[0041] After it is determined that the battery module 21 has been removed from the battery pack 11, the wireless IC 32 performs the transmission of the voltage equalization instruction signal, which was performed 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 purpose of the battery control device 40 transmitting the voltage equalization instruction signal is to equalize 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 this original purpose. In other words, 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 parameters used in calculating the SOH of each battery cell 22. Therefore, the wireless IC 32 transmits the voltage equalization instruction signal to the monitoring IC 31 so that all of the voltage equalization circuits 80 connected to each battery cell 22 are driven.

[0042] As shown in Figure 7, the monitoring IC 31 drives the voltage equalization circuit 80 in accordance with instructions. The monitoring IC 31 measures at least one of the current flowing through the voltage equalization circuit 80 and the voltage applied to the voltage equalization circuit 80. Of course, the monitoring IC 31 may measure both the current and the voltage, or may measure the temperature at that time. For example, a cell thermistor may be used to measure the temperature.

[0043] The monitoring IC 31 transmits the measured current and other data to the wireless IC 32. The wireless IC 32 calculates the battery state of the battery cell 22 using the current and other data acquired from the monitoring IC 31. In this embodiment, the "battery state of the battery cell 22" refers to the SOH (State of Health) of the battery cell 22. The SOH is also referred to as a healthy state or a degraded state. An example of a method for calculating the SOH will be described. Two indicators of the SOH are generally known: the capacity retention rate and the internal resistance increase rate. The "capacity retention rate" is the ratio of the current full capacity of a battery to the full capacity of a new battery. The "internal resistance increase rate" is the increase rate of the internal resistance that increases with battery degradation. The physical quantities that can be measured externally from a battery are the current, voltage, and temperature, making it difficult to directly measure the SOH. Therefore, methods such as the OCV (Open Circuit Voltage) estimation method and a nonlinear Kalman filter are known. The wireless IC 32 calculates the SOH using these methods. In addition to the above two indicators, there are also known methods for calculating the SOH using the SOC or the internal resistance of the battery, so the wireless IC 32 may use these to calculate the SOH. When the battery module 21 is removed from the battery pack 11, the wireless IC 32 is driven by using the battery cell 22 as a power source.

[0044] As described above, according to this embodiment, after it is determined that the battery module 21 has been removed from the battery pack 11, the wireless IC 32 discharges the battery cells 22 at a predetermined timing to calculate the SOH. As described above, in the conventional technology, charging and discharging are not performed after removal, and therefore the SOH after removal cannot be determined. In contrast, in this embodiment, the SOH is calculated by discharging the battery cells 22, making it possible to determine the SOH after removal.

[0045] Furthermore, in this embodiment, after it is determined that a battery module 21 has been removed from the battery pack 11, the wireless IC 32 transmits the voltage equalization instruction signal, which was previously transmitted by the battery control device 40 before the removal. The purpose of the battery control device 40 transmitting the voltage equalization instruction signal is to equalize the voltages of the battery cells 22, but the purpose of the wireless IC 32 transmitting the voltage equalization instruction signal is different from this purpose: to measure parameters used in calculating the SOH. In other words, in this embodiment, the wireless IC 32 uses the function that the battery control device 40 had previously performed for a purpose other than its original purpose. By using such an existing function for a different purpose, it is unnecessary to add a new function or device, which contributes to cost reduction.

[0046] In FIG. 7 , the transmission of a voltage equalization instruction signal is described as a function performed by the battery control device 40 before the battery module 21 was removed from the battery pack 11, but this is not a limitation. In short, it is sufficient to extract current from the battery cells 22. Therefore, for example, the wireless IC 32 may perform the function of transmitting a drive signal to a module equalization circuit 81 as shown in FIG. 8 . The battery control device 40 also has the function of driving a circuit for adjusting the temperature state of the battery cells 22 and a circuit for measuring the impedance of the battery cells 22, and these functions may be performed by the wireless IC 32. As described above, the purpose of driving these circuits by the wireless IC 32 is different from their original purpose and is to measure parameters used in calculating the SOH. While the voltage equalization circuit 80 and the module equalization circuit 81 have been described as being provided in the battery monitoring device 30, this is not a limitation.

[0047] Next, an example of the operation of the battery monitoring device 30 (wireless IC 32 and monitoring IC 31) will be described with reference to the flowchart of Fig. 9. The process shown in Fig. 9 is repeatedly executed at predetermined time intervals.

[0048] In step S101, after it is determined that the battery module 21 has been removed from the battery pack 11, the wireless IC 32 transmits, at a predetermined timing, a voltage equalization instruction signal that was being performed by the battery control device 40 before the battery module 21 was removed. This activates the voltage equalization circuit 80. The predetermined timing is set in advance through, for example, experiments or simulations.

[0049] The process proceeds to step S102, where the monitoring IC 31 measures at least one of the current flowing through the voltage equalization circuit 80 and the voltage applied to the voltage equalization circuit 80. The process of step S102 is repeatedly executed until a predetermined time has elapsed (step S103). The predetermined time is measured by the counter 323. After the predetermined time has elapsed, the process proceeds to step S104, where the wireless IC 32 stops the voltage equalization circuit 80. This is because the purpose of driving the voltage equalization circuit 80 is to measure the current, etc., and once the measurement of the current, etc. is completed, there is no need to drive the voltage equalization circuit 80. The process proceeds to step S105, where the wireless IC 32 calculates the SOH of the battery cell 22 using the measured current, etc., and stores the calculation result in its storage unit (e.g., memory). The SOH calculation result may be stored as the calculated value itself or in the form of a histogram.

[0050] The timing at which the calculation result of the SOH stored in the storage unit is read out is not particularly limited, but one example is when the battery module 21 is attached to the battery pack 11.

[0051] According to the first embodiment described above in detail, the following effects can be obtained.

[0052] 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 capable of supplying power to the motor 13 when the battery pack 11 or the battery module 21 is attached to the motor 13; a voltage equalization circuit 80 connected to the battery cell 22; a monitoring IC 31 that measures at least one of the current flowing through the voltage equalization circuit 80 and the voltage applied to the load section; and a wireless IC 32 that is configured to operate using the battery cell 22 as a power source when the battery pack 11 or the battery module 21 is detached from the motor 13, and that causes current to flow from the battery cell 22 to the voltage equalization circuit 80 at predetermined timing and acquires the measurement results measured by the monitoring IC 31 at that time. The motor 13 corresponds to the "external load." The battery cell 22 corresponds to the "battery section." The voltage equalization circuit 80 corresponds to the "load section." The monitoring IC 31 corresponds to the "measurement section." The wireless IC 32 corresponds to the "control section."

[0053] According to this embodiment, the battery pack 11 or battery module 21 discharges the battery cells 22 at a predetermined timing and measures the current, etc. The measured current, etc. can be used, for example, to calculate the SOH. As described above, in the conventional technology, charging and discharging are not performed after removal, so the SOH after removal cannot be determined. In contrast, in this embodiment, the SOH is calculated by discharging the battery cells 22, so it is possible to determine the SOH after removal.

[0054] In the present embodiment, the SOH of the battery cells 22 constituting the battery module 21 is mainly calculated in a state in which the battery module 21 is detached from the battery pack 11, but the present invention is not limited to this. As shown in Fig. 4, the SOH of the battery cells 22 constituting the battery pack 11 may be calculated in a state in which the battery pack 11 is detached from the vehicle 10. In recent years, various methods have emerged, such as a method in which the battery cells are directly mounted on the battery pack without constituting a battery module, a method in which the housing of the battery pack is integrated into the vehicle body and the battery module is directly mounted on the vehicle body, and a method in which the battery cells are directly mounted on the vehicle body.

[0055] Therefore, this embodiment may calculate the SOH of the battery cell 22 in a state in which the battery cell 22 directly attached to the vehicle 10 is removed from the vehicle 10. In this case, the battery monitoring device 30 is attached to the battery cell 22. Also, this embodiment may calculate the SOH of the battery cell 22 constituting the battery module 21 in a state in which the battery module 21 directly attached to the vehicle 10 is removed from the vehicle 10. In other words, the "battery unit" includes a "battery pack equipped with the battery monitoring device 30," a "battery module equipped with the battery monitoring device 30," or a "battery cell equipped with the battery monitoring device 30."

[0056] Furthermore, the wireless IC 32 may calculate and store the SOH of the battery cells 22 based on the measurement results measured by the monitoring IC 31 when the battery pack 11 or the battery module 21 is detached from the motor 13. This makes it possible to grasp the SOH after detachment.

[0057] Furthermore, when the battery pack 11 or battery module 21 is attached to the motor 13, the wireless IC 32 notifies the battery control device 40 of the measurement results measured by the monitoring IC 31 in accordance with instructions from the battery control device 40, which communicates with the wireless IC 32. Meanwhile, when the battery pack 11 or battery module 21 is detached from the motor 13, the wireless IC 32 performs SOH calculations that were not performed when the battery pack 11 or battery module 21 was attached to the motor 13. The SOH calculations that were performed by the battery control device 40 before the battery pack 11 or battery module 21 was detached are now performed by the wireless IC 32 when the battery pack 11 or battery module 21 is detached. This makes it possible to calculate the SOH without adding any new functions or devices.

[0058] The wireless IC 32 determines whether communication with the battery control device 40 has been interrupted. If it determines that communication with the battery control device 40 has been interrupted, the wireless IC 32 determines that the battery pack 11 or the battery module 21 has been removed from the motor 13, and uses this as a trigger to cause the voltage equalization circuit 80 to flow current from the battery cells 22. This enables calculation of the SOH at an appropriate timing.

[0059] The wireless IC 32 determines that communication with the battery control device 40 has been interrupted if the wireless IC 32 has not received a startup instruction signal or a battery cell 22 voltage equalization instruction signal from the battery control device 40 for a certain period of time, or if the wireless IC 32 has received a signal from the external device 70 notifying that communication has been interrupted. By using the signal transmitted from the battery control device 40 or the external device 70 in this way, it becomes possible to appropriately determine whether communication has been interrupted.

[0060] The "load section" includes circuits used to equalize voltages (voltage equalization circuit 80, module equalization circuit 81) as described in FIGS. 7 and 8. The "load section" may also include a load used to adjust the temperature state of the battery cells 22. An example of a "load used to adjust the temperature state of the battery cells 22" is a heater built into the battery pack 11 for warming the battery cells 22. The "load section" may also include a load used to pass a current when measuring the impedance of the battery cells 22. By using such an existing load, it becomes possible to calculate the SOH without adding any new functions or devices.

[0061] Second Embodiment Next, a second embodiment will be described with reference to the flowchart of Fig. 10. In the first embodiment, the voltage equalization circuit 80 is driven to discharge the battery cells 22 for a different purpose than the original purpose, and the SOH is calculated. In the second embodiment, however, the SOH is calculated using the progress of the self-discharge rate of the battery cells 22.

[0062] 10, after it is determined that the battery module 21 has been removed from the battery pack 11, the wireless IC 32 waits until a predetermined time has elapsed. After the predetermined time has elapsed (YES in step S201), the process proceeds to step S202, where the wireless IC 32 turns on a flag related to self-discharge. The wireless IC 32 may turn on the flag related to self-discharge based on an instruction from the external device 70. The process proceeds to step S203, where the wireless IC 32 stops all functions except for the counter 323. The reason for stopping all functions except for the counter 323 is to prevent current other than that caused by self-discharge from flowing in the circuit. The process proceeds to step S204, where the process waits for a predetermined time with all functions except for the counter 323 stopped (allowing the battery cells 22 to self-discharge).

[0063] After the predetermined time has elapsed (YES in step S204), the process proceeds to step S205, where the wireless IC 32 resumes the stopped function. The process proceeds to step S206, where the wireless IC 32 calculates the change in the self-discharge rate of the battery cell 22. One example of a method for calculating the change in the self-discharge rate is to calculate the change in the remaining capacity (SOC) of the battery cell 22 at the start of the predetermined time in step S204 and the rate of change in the remaining capacity (SOC) of the battery cell 22 at the end of the predetermined time. 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 change in the self-discharge rate of the battery cell 22.

[0064] According to the second embodiment, the following effects can be obtained.

[0065] The battery pack 11 or battery module 21 is configured to operate using the battery cells 22 as a power source when the battery pack 11 or battery module 21 is detached from the motor 13, and includes a wireless IC 32 that calculates the change in the self-discharge rate of the battery cells 22. The calculated change in the self-discharge rate can be used, for example, to calculate the SOH. The change in the self-discharge rate can be calculated without adding any new functions or devices, which contributes to reducing the cost of calculating the SOH.

[0066] The wireless IC 32 stops all functions except for 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, improving the accuracy of calculating the change in the self-discharge rate. The wireless IC 32 calculates the change in the self-discharge rate based on the rate of change between the remaining capacity of the battery cell 22 at the start of the predetermined time and the remaining capacity of the battery cell 22 at the end of the predetermined time. The wireless IC 32 then calculates and stores the SOH of the battery cell 22 based on the calculated change in the self-discharge rate.

[0067] <Other embodiments> In the above-described embodiment, the wireless IC 32 stores the SOH calculation result in its own storage unit. However, this is not intended to be limiting. As shown in FIG. 11 , the wireless IC 32 may transmit the SOH calculation result to an external device 70 (e.g., a cloud server) via wireless communication. Using wireless communication eliminates the need for a physical interface such as a connector. In the above-described embodiment, the wireless IC 32 calculates the SOH using measured currents, etc. However, this is not intended to be limiting. As shown in FIG. 11 , the wireless IC 32 may transmit the measured currents, etc. to the external device 70, and the external device 70 may perform the SOH calculation itself. In this case, it is sufficient for the wireless IC 32 to have the functions of storing and transmitting the measured currents, etc. Alternatively, both the wireless IC 32 and the external device 70 may calculate the SOH. In this case, the results of both calculations may be compared to determine the validity of the calculation results. If the calculation results differ, the difference may be used as a correction coefficient for the next calculation.

[0068] 12, in addition to the battery module 21 according to this embodiment, if there are battery modules 90 to 92 with different specifications, standards, etc., from the battery module 21, the SOHs calculated by these battery modules may be transmitted collectively to the external device 70. Such transmission can be achieved, for example, by unifying the communication frequency. This makes it possible to collectively manage battery modules with different specifications, standards, etc.

[0069] When the charge state of the battery cell 22 is equal to or lower than a certain value, the wireless IC 32 may stop current from flowing from the battery cell 22 to the load section. This prevents the battery cell 22 from being over-discharged.

[0070] The operation frequency of the monitoring IC 31 may be lower after the battery pack 11 is removed from the vehicle 10 compared to before the battery pack 11 was removed from the vehicle 10. One of the functions of the monitoring IC 31 is fault diagnosis, and after the battery pack 11 is removed from the vehicle 10, the number of fault diagnoses may be reduced compared to before the battery pack 11 was removed from the vehicle 10. This is because there is less need for fault diagnosis after the battery pack 11 is removed from the vehicle 10.

[0071] The signal for the wireless IC 32 to drive the voltage equalization circuit 80, the module equalization circuit 81, etc. may be a dedicated signal instead of the signal used by the battery control device 40. In other words, the signal is not limited as long as it can drive the voltage equalization circuit 80, etc.

[0072] The controller and methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the controller and methods described herein may be implemented by a special-purpose computer configured with a processor configured with one or more dedicated hardware logic circuits. Alternatively, the controller and methods described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0073] The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] A battery unit (11, 21, 22) configured to be replaceable with respect to an external load (13), a battery section (22) capable of supplying power to the external load when the battery unit is attached to the external load; a load section (80) connected to the battery section; a measuring unit (31) that measures at least one of a current flowing through the load unit and a voltage applied to the load unit; a control unit (32) configured to operate using the battery unit as a power source when the battery unit is detached from the external load, and which causes current to flow from the battery unit to the load unit at a predetermined timing and acquires the measurement results measured by the measurement unit at that time. [Configuration 2] 2. The battery unit according to configuration 1, wherein the control unit calculates and stores the battery state of the battery unit based on the measurement result when the battery unit is detached from the external load. [Configuration 3] The control unit In a state where the battery unit is attached to the external load, the measurement result is notified to the battery control device in accordance with an instruction from the battery control device that communicates with the control unit, The battery unit according to configuration 1 or 2, wherein when the battery unit is detached from the external load, the calculation of the battery state is performed, which was not performed when the battery unit was attached to the external load. [Configuration 4] a determination unit that determines whether communication between the control unit and the battery control device is interrupted; The battery unit according to configuration 3, wherein when the determination unit determines that communication with the battery control device has been interrupted, the control unit determines that the battery unit has been removed from the external load, and uses this as an opportunity to cause the load unit to flow current from the battery unit and have the measurement unit measure it. [Configuration 5] The battery unit according to configuration 4, wherein the determination unit determines that communication with the battery control device has been interrupted when a startup instruction signal or a voltage equalization instruction signal for the battery unit is not input from the battery control device for a certain period of time, or when a signal notifying that communication from an external device has been interrupted is input. [Configuration 6] The battery unit according to any one of configurations 1 to 5, wherein the load section is a load used to equalize the voltage of the battery section, a load used to adjust the temperature state of the battery section, or a load used to pass a current when measuring the impedance of the battery section. [Configuration 7] 6. The battery unit according to configuration 5, wherein the control unit is configured to be able to wirelessly communicate with the external device. [Configuration 8] 8. The battery unit according to any one of configurations 1 to 7, wherein the control unit stops current flow from the battery unit to the load unit when the charge state of the battery unit is equal to or lower than a certain value. [Configuration 9] A battery unit (11, 21, 22) configured to be replaceable with respect to an external load (13), a battery section (22) capable of supplying power to the external load when the battery unit is attached to the external load; a control unit (32) configured to operate using the battery unit as a power source when the battery unit is detached from the external load, and which calculates a change in the self-discharge rate of the battery unit. [Configuration 10] The control unit For a predetermined time, all functions except for the counter that measures the time related to self-discharge are stopped. calculating a transition of the self-discharge rate based on a rate of change between the remaining capacity of the battery module at the start of the predetermined time period and the remaining capacity of the battery module at the end of the predetermined time period; 10. The battery unit according to configuration 9, wherein the battery state of the battery unit is calculated and stored based on the calculated transition of the self-discharge rate. [Configuration 11] A battery monitoring device (30) mounted on a battery unit (11, 21, 22) configured to be replaceable with respect to an external load (13), a measuring section (31) that measures at least one of a current flowing through a load section (80) connected to a battery section (22) of the battery unit and a voltage applied to the load section; a control unit (32) configured to operate using the battery unit as a power source when the battery unit is detached from the external load, and which causes current to flow from the battery unit to the load unit at a predetermined timing and acquires the measurement results measured by the measurement unit at that time. [Explanation of symbols]

[0074] 11 battery pack, 13 motor, 21 battery module, 22 battery cell, 31 monitoring IC, 32 wireless IC, 80 voltage equalization circuit, 30 battery monitoring device

Claims

1. A battery unit (11, 21, 22) configured to be replaceable with respect to an external load (13), a battery section (22) capable of supplying power to the external load when the battery unit is attached to the external load; A load section (80) connected to the battery section; 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; a control unit (32) configured to operate using the battery unit as a power source when the battery unit is detached from the external load, and causing a current to flow from the battery unit to the load unit at a predetermined timing and acquiring a measurement result measured by the measurement unit at that time; the control unit calculates and stores a battery state of the battery unit based on the measurement result in a state in which the battery unit is detached from the external load, The control unit In a state where the battery unit is attached to the external load, the measurement result is notified to the battery control device in accordance with an instruction from the battery control device that communicates with the control unit, When the battery unit is detached from the external load, the battery unit performs the calculation of the battery state, which calculation was not performed when the battery unit was attached to the external load.

2. a determination unit that determines whether communication between the control unit and the battery control device is interrupted; 2. The battery unit according to claim 1, wherein when the determination unit determines that communication with the battery control device has been interrupted, the control unit determines that the battery unit has been removed from the external load, and uses this as an opportunity to cause the load unit to flow current from the battery unit and have the measurement unit measure it.

3. 3. The battery unit according to claim 2, wherein the determination unit determines that communication with the battery control device has been interrupted if a startup instruction signal or a voltage equalization instruction signal for the battery unit is not input from the battery control device for a certain period of time, or if a signal indicating that communication from an external device has been interrupted is input.

4. 2. The battery unit according to claim 1, wherein the load section is any one of a load used to equalize the voltages of the battery sections, a load used to adjust the temperature state of the battery sections, and a load used to pass a current when measuring the impedance of the battery sections.

5. The battery unit according to claim 3 , wherein the control unit is configured to be capable of wireless communication with the external device.

6. 6. The battery unit according to claim 1, wherein the control unit stops current flow from the battery unit to the load unit when the charge state of the battery unit is equal to or lower than a certain value.

7. A battery monitoring device (30) mounted on a battery unit (11, 21, 22) configured to be replaceable with respect to an external load (13), a measuring section (31) for measuring at least one of a current flowing through a load section (80) connected to a battery section (22) of the battery unit and a voltage applied to the load section; a control unit (32) configured to operate using the battery unit as a power source when the battery unit is detached from the external load, and causing a current to flow from the battery unit to the load unit at a predetermined timing and acquiring a measurement result measured by the measurement unit at that time; the control unit calculates and stores a battery state of the battery unit based on the measurement result in a state in which the battery unit is detached from the external load, The control unit In a state where the battery unit is attached to the external load, the measurement result is notified to the battery control device in accordance with an instruction from the battery control device that communicates with the control unit, When the battery unit is detached from the external load, the battery monitoring device performs the calculation of the battery state, which calculation was not performed when the battery unit was attached to the external load.

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