Battery management device, battery management method, and program

Abstract

This invention provides a battery management device, a battery management method, and a program capable of detecting abnormalities in a circuit that monitors the battery voltage of a lithium-ion secondary battery. [Solution] The battery management device 10 includes a first measurement circuit 15 for measuring the battery voltage of a lithium-ion secondary battery, a second measurement circuit 16 for applying a high-frequency signal of 0.1 MHz or higher to the lithium-ion secondary battery and measuring the amplitude of the resonant electrical signal, and an abnormality detection unit 23 for calculating the battery voltage of the lithium-ion secondary battery from the amplitude of the electrical signal and detecting an abnormality in the first measurement circuit 15 based on the calculated battery voltage.

Description

[Technical Field]

[0001] This invention relates to a battery management device, a battery management method, and a program. [Background technology]

[0002] To prevent the degradation of lithium-ion secondary batteries, it is necessary to suppress the increase in lithium (Li) deposited in lithium-ion secondary batteries. Patent Document 1 discloses a technique for detecting the deposition of Li inside a lithium-ion secondary battery by applying a high-frequency signal to the battery. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-108602 [Overview of the project] [Problems that the invention aims to solve]

[0004] There is potential to utilize the technology of applying a high-frequency signal to a lithium-ion secondary battery and measuring the amplitude of the resonant electrical signal for detecting abnormalities in circuits that monitor battery voltage.

[0005] This disclosure was made to solve such problems and provides a battery management device, a battery management method, and a program that can detect abnormalities in a circuit that monitors the battery voltage of a lithium-ion secondary battery. [Means for solving the problem]

[0006] The battery management device according to this disclosure includes a first measurement circuit for measuring the battery voltage of a lithium-ion secondary battery, a second measurement circuit for applying a high-frequency signal of 0.1 MHz or higher to the lithium-ion secondary battery and measuring the amplitude of the resonant electrical signal, and an abnormality detection unit for calculating the battery voltage of the lithium-ion secondary battery from the amplitude of the electrical signal and detecting an abnormality in the first measurement circuit based on the calculated battery voltage.

[0007] The battery management method according to this disclosure includes the steps of: measuring the battery voltage of a lithium-ion secondary battery using a first measurement circuit; applying a high-frequency signal of 0.1 MHz or higher to the lithium-ion secondary battery and measuring the amplitude of the resonant electrical signal; calculating the battery voltage of the lithium-ion secondary battery from the amplitude of the electrical signal; and detecting an abnormality in the first measurement circuit based on the calculated battery voltage.

[0008] The program according to this disclosure causes a battery management device, which includes a first measurement circuit for measuring the battery voltage of a lithium-ion secondary battery and a second measurement circuit for applying a high-frequency signal of 0.1 MHz or higher to the lithium-ion secondary battery and measuring the amplitude of the resonant electrical signal, to execute a process to calculate the battery voltage of the lithium-ion secondary battery from the amplitude of the electrical signal and to detect an abnormality in the first measurement circuit based on the calculated battery voltage. [Effects of the Invention]

[0009] According to this disclosure, a battery management device, a battery management method, and a program can be provided that can detect abnormalities in a circuit that monitors the battery voltage of a lithium-ion secondary battery. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram illustrating a battery management device according to Embodiment 1. [Figure 2] This is a circuit diagram illustrating a second measurement circuit according to Embodiment 1. [Figure 3]It is a diagram for explaining the operation of the second measurement circuit according to Embodiment 1. [Figure 4] It is a diagram for explaining the change of the damped oscillation waveform according to Embodiment 1. [Figure 5] It is a flowchart exemplifying the operation of the battery management device according to Embodiment 1.

Mode for Carrying Out the Invention

[0011] Hereinafter, this embodiment will be described with reference to the drawings. However, the present invention is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are simplified as appropriate.

[0012] Embodiment 1 FIG. 1 is a block diagram exemplifying a battery management device 10 according to Embodiment 1. The battery management device 10 manages the use of manufactured lithium ion secondary batteries (cells 30). The cell 30 can be used, for example, in a vehicle drive system or a home energy supply system.

[0013] First, the cell 30 to be measured will be described. The cell 30 is configured as a lithium ion secondary battery. The cell 30 may include, for example, a positive electrode, a negative electrode, and an ion conductive medium interposed between the positive electrode and the negative electrode for conducting carrier ions. The positive electrode may include, as a positive electrode active material, a sulfide containing a transition metal element, an oxide containing lithium and a transition metal element, etc. The positive electrode active material is, for example, a lithium manganese composite oxide having a basic composition formula of Li (1-x) MnO2 (0 < x < 1, etc., the same hereinafter) or Li (1-x) Mn2O4, etc., a lithium cobalt composite oxide having a basic composition formula of Li (1-x) CoO2, etc., a lithium nickel composite oxide having a basic composition formula of Li (1-x) NiO2, etc., a lithium nickel cobalt manganese composite oxide having a basic composition formula of Li (1-x) Ni a Co b Mn cA lithium nickel cobalt manganese composite oxide such as O2(a+b+c=1) can be used. Note that the "basic composition formula" means that other elements may also be included. The negative electrode may contain a carbon material or a lithium-containing composite oxide as the negative electrode active material. Examples of negative electrode active materials include inorganic compounds such as lithium, lithium alloys, and tin compounds, carbon materials capable of intercalating and deintercalating lithium ions, composite oxides containing multiple elements, and conductive polymers. Examples of carbon materials include coke, glassy carbons, graphites, non-graphitizable carbons, pyrolytic carbons, and carbon fibers. Of these, graphites such as artificial graphite and natural graphite are preferred. Examples of composite oxides include lithium titanium composite oxide and lithium vanadium composite oxide. The ion conducting medium can be, for example, an electrolyte in which a supporting salt is dissolved. Examples of supporting salts include lithium salts such as LiPF6 and LiBF4. Examples of solvents for the electrolyte include carbonates, esters, ethers, nitriles, furans, sulforanes, and dioxolanes, which can be used individually or in mixtures. Specifically, examples of carbonates include cyclic carbonates such as ethylene carbonate, propylene carbonate, vinylene carbonate, butylene carbonate, and chloroethylene carbonate, as well as linear carbonates such as dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethyl-n-butyl carbonate, methyl-t-butyl carbonate, di-i-propyl carbonate, and t-butyl-i-propyl carbonate. The ion-conducting medium can be a solid ion-conducting polymer, an inorganic solid electrolyte, a mixed material of an organic polymer electrolyte and an inorganic solid electrolyte, or an inorganic solid powder bound by an organic binder. The solid electrolyte and this cell 30 may have a separator placed between the positive and negative electrodes.

[0014] The battery management device 10 comprises, as its main hardware components, a control unit 11, a storage unit 12, a communication unit 13, an interface unit 14 (IF), a first measurement circuit 15, and a second measurement circuit 16. The control unit 11, storage unit 12, communication unit 13, interface unit 14, first measurement circuit 15, and second measurement circuit 16 are interconnected via a data bus or the like.

[0015] The control unit 11 is, for example, a processor such as a CPU (Central Processing Unit). The control unit 11 has the function of an arithmetic unit that performs control processing and calculation processing. The control unit 11 may have multiple processors. The control unit 11 may also include a processor mounted on the board on which the second measurement circuit 16 is mounted.

[0016] The storage unit 12 is, for example, a storage device such as a memory or a hard disk. The storage unit 12 is, for example, a ROM (Read Only Memory) or RAM (Random Access Memory). The storage unit 12 has the function of storing, for example, control programs and arithmetic programs executed by the control unit 11. The memory stores one or more instructions. The storage unit 12 also has the function of temporarily storing processing data, etc. The storage unit 12 may include a database. The storage unit 12 may also have multiple memories.

[0017] The communication unit 13 is an interface for communicating with other devices via a network. The interface unit 14 is, for example, a user interface (UI). The interface unit 14 includes an output device such as a display or speaker. The interface unit 14 may further include an input device such as a keyboard, touch panel, or mouse. The interface unit 14 may be configured such that the input device and the output device are integrated, for example, a touchscreen (touch panel).

[0018] The first measurement circuit 15 measures the battery voltage of the cell 30. The first measurement circuit 15 may be any circuit that can measure the voltage of the cell 30. The specific configuration of the first measurement circuit 15 is known.

[0019] The second measurement circuit 16 includes a resonance circuit that applies a high-frequency signal of 0.1 MHz or more to the cell 30. The frequency of the high-frequency signal may be 0.5 MHz or more. The resonance circuit may be, for example, an LCR resonance circuit. By applying a high-frequency signal to the cell 30, a damped oscillation waveform in which the amplitude of the resonating electrical signal gradually decays can be obtained. The second measurement circuit 16 measures the amplitude of the resonating electrical signal. The decay rate of the damped oscillation waveform is obtained from the amplitude values at two times, and the deposition of Li in the cell 30 is detected based on the decay rate. The measured amplitude is also used to detect an abnormality in the first measurement circuit 15.

[0020] FIG. 2 is a circuit diagram illustrating the second measurement circuit 16. The second measurement circuit 16 includes a resonance circuit 41, a buffer circuit 42 for sensors, and an amplitude measurement circuit 43. Note that the circuit configuration of the second measurement circuit 16 is not limited to the circuit configuration of FIG. 2. For example, the peak hold circuit 432 of the second measurement circuit 16 may be a peak hold circuit including a diode. Further, the second measurement circuit 16 may be a circuit that uses a high-speed AD converter to acquire the waveform of the damped oscillation current flowing through the resonance circuit 41.

[0021] The cell 30 to be measured has an inductance L bat , a resistance R bat , and a capacitance C bat that are connected in series with each other and is represented by an equivalent circuit. The voltage applied across the capacitance C bat corresponds to the battery voltage V bat . The inductance L bat represents the parasitic inductance of the cell 30. The resistance R bat corresponds to the real part of the impedance of the cell 30. The capacitance C bat represents the parasitic capacitance of the cell 30.

[0022] The resonant circuit 41 has an inductance L res capacitance C res , resistance R res , and switch SW res It is equipped with an inductance L. res This is also called resonant inductance. Inductance L res It may be composed of windings. Inductance L res The inductance L of the amplitude measurement circuit 43 is sec Coupled with inductance L sec Together with it, it forms a transformer. Inductance L sec It may also be composed of windings. Capacitance C res This is also called resonant capacitance. Capacitance C res This could be a passive element, such as a capacitor. Also, capacitance C res This may be a capacitive active element such as a varicap. (Switch SW) res This may be a semiconductor switch or a mechanical switch.

[0023] Inductance L res One end is connected to the positive terminal of cell 30, and the other end is connected to capacitance C. res It is connected to one end. Capacitance C res The other end is a switch SW res It is connected to one end of the switch SW res The other end is connected to the negative electrode of cell 30. Capacitance C res The discharge resistance R res They are connected in parallel.

[0024] The sensor buffer circuit 42 receives the control signal via the switch SW res The output is sent to the control unit 11. The control signal may be generated by the control unit 11. The sensor buffer circuit 42 is connected to the switch SW via buffer B and capacitance C1. res It may also be used to drive the switch SW. The control signal rises from low to high, remains high for a predetermined time, and then goes from high to low. When the control signal is high, switch SWres It turns on. Switch SW res It conducts pulsed according to the control signal. Here, pulsed conduction means that the switch SW res This refers to the action of switching from off to on, maintaining the on state for a predetermined period of time, and then switching back to off.

[0025] Switch SW res When the circuit conducts pulsed, a pulse voltage based on the output voltage of cell 30 is applied from the positive electrode of cell 30 to the resonant circuit 41. As a result, a damped oscillation current flows through the resonant circuit 41, which oscillates at the resonant frequency and then decays. The decay of the damped oscillation current is due to the discharge resistor R res or resistor R bat This is based on losses due to factors such as inductance L. res The inductance L depends on the damped oscillating current flowing through it. sec This generates an induced electromotive force with a damped oscillation waveform.

[0026] The amplitude measurement circuit 43 has an inductance L sec It includes an amplification circuit 431 and a peak hold circuit 432. As already explained, the inductance L sec The inductance L of the resonant circuit 41 is res It is coupled to the amplifier circuit 431, which has an inductance L sec The induced electromotive force generated is amplified. The amplification circuit 431 may be a differential amplifier circuit composed of, for example, an operational amplifier OP1 and resistors R1 to R4.

[0027] The peak hold circuit 432 consists of a comparator CMP and a switch SW. sp , switch SW ch , switch SW dch It includes resistor R5, capacitance C2, and operational amplifier OP2. The peak hold circuit 432 is a switch SW sp In response to the input of a control signal that controls the on / off state, the peak value of the damped oscillation waveform amplified by the amplification circuit 431 is held. The control signal may be generated by the control unit 11.

[0028] The comparator CMP compares the amplified induced electromotive force with the voltage fed back from the operational amplifier OP2. It outputs high if the amplified induced electromotive force is greater, and low otherwise. Switch SW sp One end is connected to the output terminal of the comparator CMP, and the switch SW sp Switch SW according to the output from the other end ch The on / off state is controlled, and when the output of the comparator CMP is high, the switch SW ch It turns on. One end of capacitance C2 is connected to resistor R5 and switch SW. ch It is connected to the power supply potential via [a certain connection point], and the other end of capacitance C2 is connected to ground potential.

[0029] Switch SW of the resonant circuit 41 res When it is turned on, or afterwards, switch SW sp The switch turns on and then turns off after a predetermined time. Then, the capacitance C2 is charged according to the comparison result by the comparator CMP. dch The switch turns from off to on when the charge stored in capacitance C2 is discharged. dch The control signal may also be generated by the control unit 11.

[0030] The operational amplifier OP2 constitutes a voltage follower and feeds back the voltage across capacitance C2 to the negative input terminal of comparator CMP. The operational amplifier OP2 outputs the peak value of the damped oscillation waveform amplified by the amplification circuit 431. The amplitude measurement circuit 43 may further include an A / D converter that converts the analog signal output from operational amplifier OP2 into a digital signal.

[0031] Referring to Figure 3, the operation of the second measurement circuit 16 will be explained. The horizontal axis represents time, and the vertical axis represents voltage. Waveform W1 represents the damped oscillation waveform amplified by the amplification circuit 431. Time t0 is the switch SW of the resonant circuit 41. resThis indicates the time when the switch SW of the peak hold circuit 432 was turned on. Times t1 and t2 are the times when the switch SW of the peak hold circuit 432 was turned on. sp This indicates the time when it turns on. Voltage V ph (t1) is the switch SW of the peak hold circuit 432 at time t1. sp This represents the output voltage of op-amp OP2 when it is turned on. Voltage V ph (t2) is the switch SW of the peak hold circuit at time t2. sp This represents the output voltage of the operational amplifier OP2 when it is turned on.

[0032] In reality, the voltage V is calculated using a damped oscillation waveform for one cycle. ph (t1) and V ph (t2) is not held. In other words, at time t0, switch SW res The process involves turning on the switch SW at time t1 or time t2 to generate a damped oscillation waveform. sp The process of turning on and starting peak hold is repeated sequentially, and the output voltage of op-amp OP2 is V ph (t1) or V ph It gradually follows (t2).

[0033] The waveform W2 shown in Figure 4 represents the damped oscillation waveform that occurs when a high-frequency signal is applied to the cell 30 in its initial state. The vertical arrow indicates the switch SW res This indicates the time when the device was turned on. The envelope of waveform W2 is shown by a dotted line. If Li is deposited in cell 30, for example, a damped oscillation waveform is obtained with the curve shown by the dashed line as its envelope. Therefore, the presence or absence of Li deposition can be determined based on the damping rate of the damped oscillation waveform.

[0034] Referring again to Figure 1, the battery management device 10 includes an impedance measurement unit 21, a lithium detection unit 22, and an abnormality detection unit 23 as its functions. These functions can be realized, for example, by executing a program under the control of the control unit 11. More specifically, each function can be realized by the control unit 11 executing a program (instruction) stored in the memory unit 12. Alternatively, each function may be realized by hardware such as a circuit or chip.

[0035] The impedance measurement unit 21 measures the real part of the impedance of cell 30 based on the attenuation rate of the amplitude of the electrical signal measured by the second measurement circuit 16. For example, the impedance measurement unit 21 uses equation (10) described below to determine the real part R of the impedance of cell 30 based on the attenuation rate α of the amplitude of the electrical signal. bat It is possible to calculate this.

[0036] Next, refer to the formula to find the real part R of the impedance of cell 30. bat An example of how to calculate this is explained. The voltage V is input to the positive input terminal of the comparator CMP in Figure 2. res (t) is expressed by equations (1) to (6). L in equation (1) s is the inductance L res and inductance L bat This is the series equivalent inductance, and is calculated using equation (3). In equation (1), M is the inductance L. res and inductance L sec This represents the mutual inductance between the two. In equation (1), α is the attenuation rate of the resonant signal. In equation (1), ω0 is the resonant angular frequency, which is expressed by equation (5). In equation (5), C s is capacitance C res and capacitance C bat This is the series equivalent capacitance, calculated using equation (2). In equation (1), β is the phase difference of the resonant signal, and is expressed by equation (6).

number

number

[0037] The resonance voltage V at the n-th resonance point res (t n ) is represented by Equation (7). t n represents, for example, the time when the damped oscillation waveform W1 in FIG. 3 takes the peak value. V res (t n ) corresponds, for example, to V ph (t1) or V ph (t2) in FIG. 3. [Number]

[0038] For any n = n1, n = n2 (n1 > n2), the damping ratio α is calculated by Equation (8). [Number]

[0039] R res >> R bat When, ω0 is represented by Equation (9). [Number]

[0040] R bat represents, as already described, the real part of the impedance of the lithium-ion secondary battery. Also, since the capacitance C bat of the cell 30 is very small, the imaginary part of the impedance is L batIt is expressed as follows. From equations (3) and (4) above, equation (10) holds. Also, from equations (3) and (9) above, equation (11) holds.

number

number

[0041] For example, based on the damping rate α and resonant frequency ω0 calculated using equations (8) and (9) above, L can be calculated from equation (11). bat The following is calculated. t in equation (8) n2 -t n1 This can be approximated by t2-t1 in Figure 3. And L bat Based on equation (10), R bat This is calculated.

[0042] Referring again to Figure 1, the lithium detection unit 22 of the battery management device 10 is R calculated by the impedance measurement unit 21. bat Based on this, it is detected that Li has precipitated in cell 30. The lithium detection unit 22 detects, for example, R bat If the value is smaller than the reference value, it may be detected that Li has precipitated. The reference value is R bat The values ​​may be determined based on initial values, or they may be determined based on manufacturing data and material data of cell 30. The control unit 11 may reduce the charging current and charging power of cell 30 if Li is deposited in cell 30.

[0043] The abnormality detection unit 23 determines the battery voltage V of cell 30 from the amplitude of the resonant electrical signal. bat Calculate the battery voltage V bat Based on this, the first measurement circuit 15 is detected to have an abnormality. In other words, the abnormality detection unit 23 calculates the battery voltage of cell 30 from the amplitude of the resonant electrical signal, and if the calculated battery voltage is different from the voltage measured by the first measurement circuit 15, it is detected that an abnormality has occurred in the first measurement circuit 15. The second measurement circuit 16 is detected at two time t n1 and t n2When measuring the amplitude of an electrical signal, the abnormality detection unit 23 may calculate the battery voltage from either amplitude.

[0044] Referring to equation (7) above, M and L s This is obvious from the design information of the second measurement circuit 16, and α is calculated by equation (8), and ω0 is calculated from equation (9), so t n If we know this, we can determine the amplitude V of the resonant signal. res (t n ) from V bat We can work backwards to find t using equation (6) above. n It is possible to calculate V in equation (1) above. For example, V res (t n When the phase ω0*t takes its maximum value, n +β = 2π*n (where n is an integer), and β and t n The relationship is determined based on equation (6), so t n It is possible to calculate t from the above phase relationship. For example, t can be calculated by numerical calculation, etc. n Find the candidate and select the candidate immediately after the time when peak hold was started (e.g., t1, t2 in Figure 3). n That is also acceptable.

[0045] Note that the time t is when the amplitude is at its maximum. n This can be approximated by the time when peak hold was started (e.g., t1, t2). Also, when the second measurement circuit 16 acquires a damped oscillation waveform, the anomaly detection unit 23 uses the acquired waveform data to determine t n It may be established.

[0046] The abnormality detection unit 23 may detect that an abnormality has occurred in the first measurement circuit 15 if the difference between the battery voltage calculated from the amplitude of the resonant electrical signal and the battery voltage measured by the first measurement circuit 15 exceeds a threshold.

[0047] If an abnormality is detected in the first measurement circuit 15, the abnormality detection unit 23 may output information indicating that an abnormality has occurred in the first measurement circuit 15 via the interface unit 14. Alternatively, the abnormality detection unit 23 may write log data indicating that an abnormality has occurred in the first measurement circuit 15 to the storage unit 12. If an abnormality is detected in the first measurement circuit 15, the battery management device 10 may monitor the battery voltage of cell 30 based on the battery voltage calculated by the abnormality detection unit 23.

[0048] The abnormality detection unit 23 may transmit information indicating that an abnormality has occurred in the first measurement circuit 15 to an external server or communication terminal via the communication unit 13. Based on the information received by the server, etc., a worker may repair or replace the first measurement circuit 15.

[0049] Figure 5 is a flowchart illustrating the operation of the battery management device 10. First, the first measurement circuit 15 of the battery management device 10 measures the battery voltage of cell 30 (step S11). Next, the second measurement circuit 16 of the battery management device 10 applies a high-frequency current of 0.1 MHz or higher to cell 30 and measures the amplitude of the resonant electrical signal (step S12). Next, the abnormality detection unit 23 of the battery management device 10 calculates the battery voltage of cell 30 from the amplitude of the resonant electrical signal and detects an abnormality in the first measurement circuit 15 based on the calculation result (step S13). If an abnormality in the first measurement circuit 15 is detected (YES in step S13), the abnormality detection unit 23 outputs information indicating that an abnormality has occurred in the first measurement circuit 15 (step S14). If an abnormality in the first measurement circuit 15 is not detected (NO in step S13), or after step S14, the battery management device 10 terminates processing.

[0050] The process illustrated in Figure 5 may be performed periodically. Alternatively, the process in Figure 5 may be performed when the measurement result from the first measurement circuit 15 is abnormal. When the measurement result from the first measurement circuit 15 is abnormal, there is a possibility that the abnormality is in the cell 30 or in the first measurement circuit 15. By performing the process in Figure 5, the battery management device 10 can determine whether the abnormality is in the cell 30 or the first measurement circuit 15. For example, a worker may refer to the detection result from the abnormality detection unit 23 and repair or replace whichever of the cell 30 or the first measurement circuit 15 is abnormal.

[0051] Embodiment 1 can detect abnormalities in a circuit that measures the voltage of a lithium-ion secondary battery.

[0052] Although embodiments of the present invention have been described above, the present invention includes appropriate modifications that do not impair its purpose and advantages, and is not limited by the above embodiments.

[0053] The first measurement circuit 15 and the second measurement circuit 16 do not need to be provided in all cells, but may be provided in specific cells. Furthermore, the first measurement circuit 15 and the second measurement circuit 16 may be provided in each battery module, which is a combination of multiple cells, or in each battery pack.

[0054] The program described above includes, when loaded into a computer, a set of instructions (or software code) for causing the computer to perform one or more of the functions described in the embodiments. The program may be stored in a non-temporary computer-readable medium or a physical storage medium. Examples, but not limited to, include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technologies, CD-ROM, digital versatile disk (DVD), Blu-ray® disc or other optical disc storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices. The program may be transmitted over a temporary computer-readable medium or a communication medium. Examples, but not limited to, include temporary computer-readable medium or a communication medium that includes electrically, optically, acoustically, or otherwise propagating signals. [Explanation of symbols]

[0055] 10...Battery management device, 11...Control unit, 12...Storage unit, 13...Communication unit, 14...Interface unit, 15...First measurement circuit, 16...Second measurement circuit, 21...Impedance measurement unit, 22...Lithium detection unit, 23...Anomaly detection unit, 30...Cell, 41...Resonance circuit, 42...Sensor buffer circuit, 43...Amplitude measurement circuit, 431...Amplification circuit, 432...Peak hold circuit

Claims

1. A first measurement circuit for measuring the battery voltage of a lithium-ion secondary battery, A second measurement circuit applies a high-frequency signal of 0.1 MHz or higher to the lithium-ion secondary battery and measures the amplitude of the resonant electrical signal. An abnormality detection unit calculates the battery voltage of the lithium-ion secondary battery from the amplitude of the electrical signal and detects an abnormality in the first measurement circuit based on the calculated battery voltage. A battery management device equipped with the following features.

2. An impedance measuring unit that measures the real part of the impedance of the lithium-ion secondary battery based on the attenuation rate of the amplitude of the electrical signal, A lithium detection unit that detects the deposition of Li in the lithium-ion secondary battery based on the actual impedance. The battery management device according to claim 1, comprising:

3. The abnormality detection unit calculates the battery voltage of the lithium-ion secondary battery based on the resonant frequency of the electrical signal, the attenuation rate of the amplitude of the electrical signal, and the phase difference. The battery management device according to claim 1 or 2.

4. The first measurement circuit and the second measurement circuit are provided for each battery cell of the lithium-ion secondary battery. The battery management device according to claim 1 or 2.

5. The second measurement circuit includes a resonant circuit for applying the high-frequency signal to the lithium-ion secondary battery and a peak-hold circuit for measuring the amplitude of the electrical signal. The battery management device according to claim 1 or 2.

6. The steps include: measuring the battery voltage of a lithium-ion secondary battery using a first measurement circuit; The steps include applying a high-frequency signal of 0.1 MHz or higher to the lithium-ion secondary battery and measuring the amplitude of the resonant electrical signal, The steps include: calculating the battery voltage of the lithium-ion secondary battery from the amplitude of the electrical signal, and detecting an abnormality in the first measurement circuit based on the calculated battery voltage; Battery management methods including

7. A battery management device comprising a first measurement circuit for measuring the battery voltage of a lithium-ion secondary battery, and a second measurement circuit for applying a high-frequency signal of 0.1 MHz or higher to the lithium-ion secondary battery and measuring the amplitude of the resonant electrical signal, The process involves calculating the battery voltage of the lithium-ion secondary battery from the amplitude of the electrical signal, and then executing a process to detect an abnormality in the first measurement circuit based on the calculated battery voltage. program.

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