JP2010140762A - Determination device for determining lithium ion battery state - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a determination device which determines a state (a deposition amount of lithium metal) of lithium metal. <P>SOLUTION: The determination device determines a state of a lithium ion battery 20 which outputs energy used when a vehicle 1 travels and receives regeneration energy in response to switching from on to off of an accelerator 101 of the vehicle, and includes an estimation means 90 for estimating the deposition amount of the lithium metal in the lithium ion battery. The estimation means counts the number of times that an accelerator opening variation upon switching of the accelerator from on to off exceeds a predetermined value, and estimates the deposition amount of the lithium metal by using data presenting relationship between the count value and the deposition amount of the lithium metal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a discrimination device that discriminates the state of a lithium ion battery in a configuration in which the lithium ion battery outputs energy used for traveling of the vehicle and accepts regenerative energy in response to switching of an accelerator from on to off. Is.

  Lithium ion batteries tend to deteriorate battery characteristics due to overcharge and overdischarge. For example, when a lithium ion battery is overcharged, lithium metal may be deposited on the negative electrode. If lithium metal is deposited, the charge capacity of the lithium ion battery may decrease, or the heat resistant temperature of the lithium ion battery may decrease. Therefore, conventionally, techniques for suppressing the precipitation of lithium metal have been proposed.

  In the charging circuit described in Patent Document 1, charging is performed while the secondary battery is heated. This suppresses the deposition of lithium metal on the negative electrode surface in a low temperature environment.

  In the vehicle battery control device described in Patent Document 2, when it is predicted that the battery is likely to reach an extremely low temperature state, the amount of charge of the battery is increased, and the battery temperature is equal to or lower than a predetermined temperature. To discharge the battery. And by raising the temperature of a battery with the internal heat_generation | fever of a battery, it has suppressed that lithium metal precipitates in a very low temperature state.

The secondary battery described in Patent Document 3 is provided with a third electrode (an electrode different from the positive electrode and the negative electrode) for inserting a part or all of lithium ions when an abnormality occurs due to precipitation of lithium metal. . In this way, lithium ions are inserted into the third electrode to suppress the precipitation of lithium metal.
JP 2007-330008 (paragraphs 0004 and 0010) JP 2008-16229 A (paragraph 0007) Japanese Patent Laid-Open No. 10-83806 (paragraphs 0007-0008)

  However, with the techniques described in Patent Documents 1-3, it is impossible to estimate how much lithium metal is deposited in the lithium ion battery.

  Accordingly, an object of the present invention is to estimate the amount of lithium metal deposited in a lithium ion battery.

  The present invention is a discrimination device that outputs energy used for running a vehicle and discriminates a state of a lithium ion battery that accepts regenerative energy in response to a vehicle accelerator being switched from on to off. There is an estimation means for estimating the amount of lithium metal deposited at. And the estimation means counts the number of times that the amount of change in the accelerator opening when the accelerator is switched from on to off exceeds a predetermined value, and uses data indicating the relationship between this count value and the amount of lithium metal deposited Estimate the amount of lithium metal deposited.

  Here, a temperature detection unit for detecting the temperature of the lithium ion battery is provided, and the above-described counting operation can be performed when the temperature detected by the temperature detection unit is equal to or lower than a predetermined temperature. Then, the count value can be corrected using a weighting factor related to the temperature of the lithium ion battery. Here, the weighting coefficient can be changed according to the difference between the detected temperature and the predetermined temperature. Thereby, the precipitation amount of lithium metal according to the difference between the detected temperature and the predetermined temperature can be estimated.

  In addition, voltage detection means for detecting the voltage of the lithium ion battery is provided, and the above-described counting operation can be performed when the voltage detected by the voltage detection means is equal to or higher than a predetermined voltage. Then, the count value can be corrected using a weighting factor related to the voltage of the lithium ion battery. Here, the weighting factor can be changed according to the difference between the detected voltage and the predetermined voltage. Thereby, the precipitation amount of lithium metal according to the difference between the detection voltage and the predetermined voltage can be estimated.

  Furthermore, the above-described counting operation can be performed when the power input to the lithium ion battery is equal to or higher than a predetermined power. The predetermined power may be power that allows input (charging) in the lithium ion battery. Then, the count value can be corrected using a weighting factor related to the electric power input to the lithium ion battery. Here, the weighting factor can be changed according to the difference between the power input to the lithium ion battery and the predetermined power. Accordingly, it is possible to estimate the amount of lithium metal deposited according to the difference between the power input to the lithium ion battery and the predetermined power.

  If the amount of precipitation of lithium metal in the lithium ion battery can be estimated by the discrimination device of the present invention, charging / discharging of the lithium ion battery can be controlled based on this estimation result. Specifically, when the estimated amount of deposited lithium metal is larger than a predetermined amount, at least one of charging and discharging of the lithium ion battery can be restricted. Here, restricting charging includes not only reducing the charge amount of the lithium ion battery but also prohibiting charging of the lithium ion battery. Similarly, limiting the discharge includes not only reducing the discharge amount of the lithium ion battery but also prohibiting the discharge of the lithium ion battery.

  According to the present invention, the amount of lithium metal deposited in a lithium ion battery can be estimated based on the amount of change in accelerator opening. In other words, the amount of lithium metal deposited due to the change in accelerator opening can be estimated. And the deterioration state of a lithium ion battery can be discriminate | determined by estimating the precipitation amount of a lithium metal.

  Examples of the present invention will be described below.

  A vehicle including a determination device that is Embodiment 1 of the present invention will be described. First, a part of the configuration of the vehicle according to the present embodiment will be described with reference to FIG.

  The vehicle 1 includes an engine (internal combustion engine) 10 and a battery 20 that can output energy necessary for traveling of the vehicle 1. The battery 20 includes a battery module in which a plurality of secondary batteries are electrically connected in series, and a case that houses the battery module. As the secondary battery, a lithium ion battery is used. The number of secondary batteries constituting the battery 20 can be set as appropriate based on the desired output.

  In this embodiment, the vehicle 1 equipped with the engine 10 will be described, but the present invention is not limited to this. For example, a fuel cell (not shown) can be used instead of the engine 10, or the engine 10 can be omitted and only the battery 20 can be used.

  The power generated by the engine 10 is divided into two paths by the power distribution mechanism 30. One path is a path for driving the wheels 50 via the speed reducer 40. The other path is a path for generating power by driving the generator 60.

  The generator 60 generates power by receiving the power of the engine 10 distributed by the power distribution mechanism 30. The electric power generated by the generator 60 is selectively used according to the operating state of the vehicle 1 and the state of charge (SOC) of the battery 20. For example, during normal traveling or sudden acceleration, the electric power generated by the generator 60 becomes electric power for driving the motor 70. Here, the power output from the battery 20 is also the power for driving the motor 70. On the other hand, when the SOC of battery 20 is lower than a predetermined reference value, the power (AC power) generated by generator 60 is converted to DC power by inverter 81 of PCU (Power Control Unit) 80. The The voltage is adjusted by the DC / DC converter 82 and then stored in the battery 20.

  The motor 70 is driven by at least one of the electric power stored in the battery 20 and the electric power generated by the generator 60. The driving force of the motor 70 is transmitted to the wheels 50 through the speed reducer 40. As a result, the motor 70 can drive the vehicle 1 while assisting the engine 10, or can drive the vehicle 1 using only the driving force of the motor 70. As the motor 70, a three-phase AC motor can be used.

  On the other hand, at the time of regenerative braking of the vehicle 1, the motor 70 is driven by the wheel 50 via the speed reducer 40, and the motor 70 operates as a generator. That is, the motor 70 can convert the kinetic energy of the wheels 50 into electric energy and generate regenerative braking. Electric power (regenerative energy) generated by the motor 70 is stored in the battery 20 via the inverter 81.

  The ECU (Electronic Control Unit) 90 includes a CPU (Central Processing Unit) 91 and a memory 92. The CPU 91 performs a predetermined calculation process based on the state of the vehicle 1, and the ECU 90 controls devices mounted on the vehicle so that the vehicle 1 is in a desired driving state. The accelerator opening sensor 100 detects the operation amount of the accelerator pedal 101 and outputs the detection result to the ECU 90. The ECU 90 detects the accelerator opening [%] based on the output of the accelerator opening sensor 100 and controls the driving of the throttle valve.

  Next, a configuration used for charge / discharge control of the battery 20 will be described with reference to FIG. Here, the same reference numerals are used for the same members as those described in FIG.

  The battery 20 has a plurality of secondary batteries (lithium ion batteries) 21 electrically connected in series. The voltage detection circuit 22 detects the voltage of each secondary battery 21 constituting the battery 20 and outputs the detection result to the ECU 90. In this embodiment, the voltages of all the secondary batteries 21 constituting the battery 20 are detected, but the present invention is not limited to this. For example, the battery 20 can be divided into blocks including a plurality of secondary batteries 21 and the voltage of each block can be detected. And the charging / discharging control (refer FIG. 3) of the battery 20 mentioned later can be performed using this voltage value.

  Further, the temperature sensor 23 is attached to the battery 20, and the ECU 90 detects the temperature of the battery 20 based on the output of the temperature sensor 23. As the temperature sensor 23, a thermocouple or a thermistor can be used. In this embodiment, one temperature sensor 23 is used, but a plurality of temperature sensors 23 can also be used. For example, a temperature sensor 23 can be provided for each secondary battery 21, or one temperature sensor 23 can be provided for a plurality of secondary batteries 21.

  Relay 83 is switched between on and off based on a control signal from ECU 90. Here, when the relay 83 is on, charging / discharging of the battery 20 is allowed, and when the relay 83 is off, charging / discharging of the battery 20 is prohibited.

  Next, charge / discharge control of the battery 20 in the present embodiment will be described with reference to the flowchart shown in FIG. The processing shown in FIG. 3 is performed by the ECU 90.

  In step S <b> 10, the ECU 90 detects the voltage of the secondary battery 21 constituting the battery 20 based on the output of the voltage detection circuit 22. Further, the ECU 90 detects the temperature of the battery 20 based on the output of the temperature sensor 23. Further, the ECU 90 detects the accelerator opening based on the output of the accelerator opening sensor 100.

  Here, the detection of the accelerator opening degree is started when the accelerator is switched from OFF to ON by the operation of the accelerator pedal 101. While the accelerator is on, the ECU 90 continues to detect the accelerator opening based on the output of the accelerator opening sensor 100. Here, the accelerator opening changes in accordance with the operation amount of the accelerator pedal 101. Based on the history of changes in the accelerator opening, the amount of change in the accelerator opening can be detected. If the operation of the accelerator pedal 101 is stopped, the accelerator is switched from on to off. Then, the regenerative braking described above occurs in response to the accelerator switching from on to off.

  In step S11, the ECU 90 determines whether or not the voltage Vd detected in step S10 is equal to or higher than a predetermined voltage Vt. If the detected voltage Vd is equal to or higher than the predetermined voltage Vt, the process proceeds to step S12. Otherwise, the process returns to step S10. The predetermined voltage Vt is a voltage value at which lithium metal is predicted to be deposited in the secondary battery (lithium ion battery) 21 and can be set in advance based on experiments. Here, when the voltage of the secondary battery 21 rises, in other words, if it is charged excessively, lithium metal may be deposited.

  In step S12, the ECU 90 determines whether or not the temperature Td of the battery 20 detected in step S10 is equal to or lower than a predetermined temperature Tt. If the detected temperature Td is equal to or lower than the predetermined temperature Tt, the process proceeds to step S13, and otherwise, the process returns to step S10. Like the predetermined voltage Vt, the predetermined temperature Tt is a temperature at which lithium metal is predicted to be deposited in the secondary battery 21, and can be set in advance based on experiments. Here, when the temperature of the secondary battery 21 is lowered, lithium metal may be deposited.

  In step S13, the ECU 90 obtains a change amount Ad of the accelerator opening based on the accelerator opening detected in step S10. Specifically, the change amount Ad of the accelerator opening between the time when the accelerator is turned on and the time when the accelerator is turned off is obtained. Then, it is determined whether or not the change amount Ad of the accelerator opening is equal to or greater than a predetermined value At. If the change amount Ad is equal to or greater than the predetermined value At, the process proceeds to step S14, and otherwise, the process returns to step S10. Like the predetermined voltage Vt, the predetermined value At is the amount of change in the accelerator opening that is predicted to deposit lithium metal in the secondary battery 21, and can be set in advance based on experiments. Here, if the amount of change in the accelerator opening is too large, the power input to the battery 20 may increase, resulting in an overcharged state.

  In step S14, the ECU 90 (CPU 91) calculates a count value. Specifically, when the detected voltage Vd is equal to or higher than the predetermined voltage Vt and the detected temperature Td is equal to or higher than the predetermined temperature Tt, the number of times the change amount Ad of the accelerator opening exceeds the predetermined value At is counted. That is, when the detected voltage Vd and the detected temperature Td satisfy the above-described predetermined conditions, the count value “1” is added each time the accelerator opening change amount Ad exceeds the predetermined value At.

In this embodiment, the count value “1” is corrected using the weighting factor K related to the temperature of the battery 20 and the weighting factor L related to the excess power of the battery 20. The excess power refers to the amount of power input to the battery 20 that exceeds the input power allowed by the battery 20 (a preset threshold). Specifically, the count value N when the change amount Ad of the accelerator opening exceeds a predetermined value At is calculated based on the following equation.
Count value N = 1 [times] × weighting coefficient K × weighting coefficient L

  Here, the relationship (one example) between the temperature of the battery 20 and the weighting coefficient K is shown in FIG. As shown in FIG. 4, the weighting factor K increases as the temperature of the battery 20 decreases. This is because the possibility that lithium metal is deposited in the secondary battery 21 increases as the temperature of the battery 20 decreases. The data shown in FIG. 4 can be stored in the memory 92, and can be set as appropriate based on the relationship between the temperature of the secondary battery 21 and the deposition of lithium metal.

  In this embodiment, the data shown in FIG. 4 is stored as a map, and the weighting coefficient K is specified from the detected temperature of the battery 20. Note that the present invention is not limited to this, and specifically, the weighting coefficient K corresponding to the detected temperature of the battery 20 can be calculated using an arithmetic expression that defines the relationship shown in FIG.

  FIG. 5 shows a relationship (an example) between the excess power and the weighting factor L. As shown in FIG. 5, the weighting factor L increases as the excess power increases. This is because the possibility that lithium metal is deposited in the secondary battery 21 increases as the excess power increases. The data shown in FIG. 5 can be stored in the memory 92 and can be set as appropriate based on the relationship between lithium metal deposition and excess power.

  In this embodiment, the data shown in FIG. 5 is stored as a map, and the weighting factor L is specified from the excess power. Note that the present invention is not limited to this, and specifically, the weighting factor L corresponding to excess power can be calculated using an arithmetic expression that defines the relationship shown in FIG. On the other hand, a weighting factor relating to the overvoltage of the secondary battery 21 may be used instead of the weighting factor relating to excess power. That is, the relationship between the difference when the voltage of the secondary battery 21 exceeds a predetermined value and the weighting coefficient is set, and the weighting coefficient is specified based on the actually detected voltage of the secondary battery 21. it can.

  When the count value N described above is calculated for the first time, in other words, when the change amount of the accelerator opening exceeds the predetermined value for the first time, the count value N is stored in the memory 92. On the other hand, when the count value N is calculated for the second time or later, the count value N is added to the count value stored in the memory 92, and the count value (cumulative value) after addition is newly stored in the memory 92. Is done.

  In step S <b> 15, the CPU 91 obtains the amount of lithium metal deposited in the secondary battery 21 based on the count value (cumulative value) stored in the memory 92. Specifically, the relationship between the lithium metal deposition amount and the count value is obtained in advance by experiments, and data indicating this relationship is stored in the memory 92. For example, the data shown in FIG. 6 can be stored in the memory 92. As shown in FIG. 6, when the count value (cumulative value) increases, the amount of lithium metal deposited increases. In this example, it is assumed that the amount of lithium metal deposited increases as the count value increases.

  If the count value (cumulative value) is specified by the process of step S14, the amount of lithium metal deposited can be specified using the data shown in FIG. In the present embodiment, the data shown in FIG. 6 is stored as a map, and the amount of lithium metal deposited is specified from the count value. However, the present invention is not limited to this. Specifically, the amount of lithium metal deposited can be calculated from the count value using an arithmetic expression that defines the relationship shown in FIG.

  In step S16, the ECU 90 determines whether or not the lithium metal precipitation amount Dd specified in step S15 is equal to or greater than a predetermined amount Dt. Here, if the precipitation amount Dd is equal to or greater than the predetermined amount Dt, the process proceeds to step S17, and if not, the process returns to step S10.

  In step S17, the ECU 90 switches the relay 83 from on to off. Thereby, charging / discharging with respect to the battery 20 is prohibited. Instead of prohibiting charging / discharging of the battery 20, the amount of charge and the amount of discharge of the battery 20 can be reduced. Specifically, the ECU 90 can set a limit value for the power to be charged in the battery 20 and can control so that the charging power to the battery 20 does not exceed the limit value. Similarly, the ECU 90 can set a limit value for the electric power discharged from the battery 20 and control so that the discharged electric power from the battery 20 does not exceed the limit value.

  According to the present embodiment, the amount of lithium metal deposited in the secondary battery 21 can be estimated based on the voltage of the secondary battery 21, the temperature of the battery 20, and the amount of change in the accelerator opening. If the amount of lithium metal deposited can be estimated, the degree of deterioration of the battery 20 (secondary battery 21) can be determined.

  Here, in this embodiment, the deposition amount of lithium metal is estimated using three parameters such as the voltage of the secondary battery 21, the temperature of the battery 20, and the amount of change in the accelerator opening, but this is not limitative. It is not a thing.

  Specifically, the amount of lithium metal deposited can be estimated based only on the amount of change in the accelerator opening. That is, by the same method as in the present embodiment, the number of times the amount of change in the accelerator opening during a period from when the accelerator is turned on until it is turned off is counted, and the lithium metal corresponding to this count value is counted. The amount of precipitation can also be specified. Here, the count value can be corrected using weighting factors (see FIGS. 4 and 5) related to parameters such as the voltage of the secondary battery 21, the power input to the battery 20, and the temperature of the battery 20.

  Further, not only the amount of change in the accelerator opening, but also the amount of lithium metal deposited can be estimated based on the voltage of the secondary battery 21 or the temperature of the battery 20. That is, when the voltage of the secondary battery 21 is equal to or higher than the predetermined voltage or the temperature of the battery 20 is equal to or lower than the predetermined temperature, the number of times the change amount of the accelerator opening exceeds the predetermined value is counted. It is also possible to specify the amount of lithium metal deposited corresponding to the above. Here, the count value can be corrected using a weighting factor (see FIGS. 4 and 5) related to the voltage of the secondary battery 21 or the temperature of the battery 20.

  On the other hand, in this embodiment, as described in step S11 in FIG. 3, it is determined whether or not the detected voltage of the battery 20 (secondary battery 21) is equal to or higher than a predetermined voltage. Absent. Specifically, instead of this process, it can also be determined whether or not the power input to the battery 20 is equal to or greater than a predetermined power. Here, the predetermined power can be input power allowed by the battery 20 described above.

  Next, a determination device that is Embodiment 2 related to the present invention will be described. Here, the same members as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Hereinafter, differences from the first embodiment will be mainly described.

  In Example 1, as shown in FIG. 6, the amount of lithium metal deposited is specified using data indicating the correspondence between the count value (cumulative value) and the amount of deposited lithium metal. On the other hand, in this embodiment, as shown in FIG. 7, the amount of lithium metal deposited is specified based on the temperature of the battery 20 and the excess power. The data shown in FIG. 7 can be acquired in advance based on experiments, and can be stored in the memory 92 of the ECU 90.

  In FIG. 7, data indicating the correspondence between the amount of lithium metal deposited and the temperature of the battery 20 is provided for each magnitude of excess power. That is, the data indicating the correspondence between the amount of deposited lithium metal and the temperature of the battery 20 varies depending on the magnitude of the excess power. According to the data shown in FIG. 7, if the temperature of the battery 20 and the magnitude of excess power are known, the amount of lithium metal deposited can be specified. Here, in the plurality of data shown in FIG. 7, when the amount of excess power actually obtained does not match, data indicating excess power closest to the actual amount of excess power may be used.

  In this embodiment, every time the amount of change in the accelerator opening exceeds a predetermined value, the amount of lithium metal deposited is specified using the data shown in FIG. Here, the precipitation amount of lithium metal specified based on the data shown in FIG. 7 indicates the precipitation amount per time when the change amount of the accelerator opening exceeds a predetermined value. For this reason, when the amount of change in the accelerator opening exceeds a predetermined value becomes multiple times, by accumulating the deposition amount of lithium metal specified every time the change in the accelerator opening exceeds the predetermined value The amount of lithium metal deposited in the current secondary battery 21 can be estimated.

  FIG. 8 shows a flowchart of charge / discharge control of the battery 20 in the present embodiment. The process illustrated in FIG. 8 is obtained by omitting the process of step S14 from the processes described in FIG. 3 of the first embodiment. Further, the process in step S24 in the present embodiment is different from the process in step S15 in the first embodiment. That is, in the process of step S24, as described above, the precipitation amount of lithium metal is estimated using the data shown in FIG. Since the other processes except step S24 are the same as those in the first embodiment, detailed description thereof is omitted.

  In step S24, the ECU 90 specifies the amount of lithium metal deposited from the data shown in FIG. 7 based on the temperature of the battery 20 and the magnitude of excess power. Here, when the amount of change in the accelerator opening exceeds a predetermined value for the first time, the identified lithium metal deposition amount is stored in the memory 92. The memory 92 may store information related to the amount of lithium metal deposited. On the other hand, when the number of times the change amount of the accelerator opening exceeds the predetermined value is the second time or later, the lithium metal deposition amount specified this time with respect to the lithium metal precipitation amount stored in the memory 92 in advance. Is added. That is, every time the amount of lithium metal deposited is specified, the amount of lithium metal deposited is accumulated. As a result, the amount of deposition stored in the memory 92 indicates the amount of lithium metal that is predicted to be deposited in the current battery 20.

  Also in the present embodiment, it is possible to estimate the amount of lithium metal deposited due to the amount of change in the accelerator opening, and the deterioration state of the secondary battery 21 can be determined.

It is the schematic which shows the structure of a part of vehicle in Example 1 of this invention. In Example 1, it is the schematic which shows the structure used for control of a battery. In Example 1, it is a flowchart which shows control of charging / discharging of a battery. In Example 1, it is a figure which shows the relationship between the weighting coefficient used for calculation of a count value, and battery temperature. In Example 1, it is a figure which shows the relationship between the weighting coefficient used for calculation of a count value, and excess electric power. In Example 1, it is a figure which shows the relationship between a count value and the precipitation amount of a lithium metal. In Example 2, it is a figure which shows the relationship between battery temperature and the precipitation amount of a lithium metal. In Example 2, it is a flowchart which shows control of charging / discharging of a battery.

Explanation of symbols

1: Vehicle 10: Engine 20: Battery 21: Secondary battery (lithium ion battery)
22: Voltage detection circuit (voltage detection means) 23: Temperature sensor (temperature detection means)
30: Power distribution mechanism 40: Reducer 50: Wheel 60: Generator 70: Motor 80: PCU (Power Control Unit)
81: Inverter 82: DC / DC converter 83: Relay 90: ECU (Electronic Control Unit, estimation means)
91: CPU 92: Memory 100: Accelerator opening sensor 101: Accelerator

Claims (8)

A discriminating device that outputs energy used for traveling of a vehicle and discriminates a state of a lithium ion battery that receives regenerative energy in response to the accelerator of the vehicle being switched from on to off,
Having estimation means for estimating the amount of lithium metal deposited in the lithium ion battery;
The estimation means counts the number of times that the amount of change in accelerator opening when the accelerator is switched from on to off exceeds a predetermined value, and uses data indicating the relationship between the count value and the amount of lithium metal deposited A discriminating apparatus for estimating a deposition amount of lithium metal. Having temperature detecting means for detecting the temperature of the lithium ion battery;
The discrimination device according to claim 1, wherein the estimation unit performs a counting operation when a temperature detected by the temperature detection unit is equal to or lower than a predetermined temperature.   The discriminating apparatus according to claim 2, wherein the estimation unit corrects the count value using a weighting coefficient that changes in accordance with a difference between the detected temperature and the predetermined temperature. Voltage detecting means for detecting the voltage of the lithium ion battery;
4. The determination device according to claim 1, wherein the estimation unit performs a counting operation when a voltage detected by the voltage detection unit is equal to or higher than a predetermined voltage. 5.   The discriminating apparatus according to claim 4, wherein the estimation unit corrects the count value using a weighting coefficient that changes in accordance with a difference between the detection voltage and the predetermined voltage.   4. The determination device according to claim 1, wherein the estimation unit performs a counting operation when power input to the lithium ion battery is equal to or higher than a predetermined power. 5.   7. The determination according to claim 6, wherein the estimation unit corrects the count value by using a weighting factor that changes in accordance with a difference between the power input to the lithium ion battery and the predetermined power. apparatus. A discrimination device according to any one of claims 1 to 7,
A controller for controlling charging and discharging of the lithium ion battery,
The control device restricts at least one of charging and discharging of the lithium ion battery when the amount of deposited lithium metal estimated by the estimating unit is larger than a predetermined amount.

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