Servers and external terminals for the secondary battery degradation scheduling system, and the degradation scheduling system.

Abstract

Invention details;

Description

Server and external terminal for secondary battery deterioration determination system, deterioration determination system CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2020-113171 filed on June 30, 2020, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a system for determining a deterioration level of a secondary battery.

[0003] Secondary batteries have been widely used as power sources for various devices. Secondary batteries deteriorate with use, but the degree of deterioration varies. Therefore, it is necessary to obtain the degree of deterioration for each secondary battery. Since it is difficult to directly detect the degree of deterioration from the secondary battery, it is estimated from various information about the secondary battery. For example, Patent Literature 1 discloses a configuration for estimating the degree of deterioration of the full charge capacity of a secondary battery based on a predetermined criterion using the battery capacity history of the secondary battery.

[0004] Re-table 2012 / 137456 publication

[0005] In the configuration disclosed in Patent Document 1, the criteria for estimating the degree of deterioration are prepared in advance. However, because the tendency of secondary battery deterioration changes over time, it is difficult to maintain high accuracy in a configuration in which the degree of deterioration is estimated based on the prepared criteria without changing the criteria for estimating the degree of deterioration accordingly.

[0006] The present disclosure provides a system for determining the deterioration level of a secondary battery that can determine the deterioration level of a secondary battery with high accuracy.

[0007] One aspect of the present disclosure is a server for a deterioration degree determination system for determining the deterioration degree of a secondary battery, comprising: an estimation formula storage unit that stores an estimation formula for determining the deterioration degree based on battery characteristics relating to the transition of the battery state of the secondary battery over a predetermined voltage range or battery characteristic related values ​​relating to the battery characteristics; and an update unit that updates the estimation formula stored in the estimation formula storage unit based on battery characteristics relating to the transition of the battery state of the secondary battery obtained by charging and discharging the secondary battery in an external terminal.

[0008] Another aspect of the present disclosure is an external terminal for a system for determining the degree of deterioration of a secondary battery, the external terminal including a server for determining the degree of deterioration in which an estimation formula for determining the degree of deterioration of a secondary battery is stored, the external terminal comprising: a battery characteristic acquisition unit that acquires battery characteristics relating to the transition of the battery state of the secondary battery over a predetermined voltage range; and a transmission unit that transmits the battery characteristics acquired by the battery characteristic acquisition unit or battery characteristic-related values ​​relating to the battery characteristics to the server.

[0009] Yet another aspect of the present disclosure is a system for determining the degree of deterioration of a secondary battery, which includes the server and the external terminal, and is configured to determine the degree of deterioration in the server or the external terminal based on a comparison result between the estimation formula and the battery characteristics or the battery characteristic-related value.

[0010] In the server for the system for determining the deterioration level of a secondary battery according to the above aspect, the estimation formula for determining the deterioration level is configured to be updated based on battery characteristics relating to the transition of the battery state of the secondary battery acquired by discharging the secondary battery. This allows the estimation formula to follow the deterioration trend of the secondary battery, which changes over time, making it possible to determine the deterioration level of the secondary battery with high accuracy.

[0011] The external terminal for the secondary battery deterioration determination system according to the other aspect has a configuration suitable for updating the estimation formula for determining the deterioration level by the server, and by using the external terminal together with the server, the estimation formula can be made to follow the deterioration trend of the secondary battery, which changes over time, thereby enabling the deterioration level of the secondary battery to be determined with high accuracy.

[0012] In yet another aspect, the system for determining the degree of deterioration of a secondary battery includes the server and the external terminal, and is configured to determine the degree of deterioration of the secondary battery, and is configured to be suitable for updating the estimation formula used to determine the degree of deterioration in the server. This allows the estimation formula to follow the tendency of deterioration of the secondary battery, which changes over time, making it possible to determine the degree of deterioration of the secondary battery with high accuracy.

[0013] As described above, according to one aspect of the present disclosure, it is possible to provide a system for determining the deterioration level of a secondary battery that is capable of determining the deterioration level of a secondary battery with high accuracy.

[0014] Note that the symbols in parentheses in the claims indicate the correspondence with the specific means described in the embodiments described below, and do not limit the technical scope of the present disclosure.

[0015] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0016] FIG. 1 is a conceptual diagram showing the configuration of a deterioration level determination system in embodiment 1, FIG. 2 is a conceptual diagram showing the configuration of a battery pack in embodiment 1 and a conceptual diagram of a vehicle equipped with the battery pack, FIG. 3 is a conceptual diagram showing battery characteristics in embodiment 1, FIG. 4 is a conceptual diagram showing pass / fail determination criteria in embodiment 1, FIG. 5 is a flow diagram showing a method for determining the deterioration level of a secondary battery in embodiment 1, FIG. 6 is a flow diagram showing a method for manufacturing a battery pack in embodiment 1, and FIG. 7 is a flow diagram showing a method for determining the deterioration level of a secondary battery in modified embodiment 1. 8 is a flow diagram showing a method for determining the deterioration level of a secondary battery in modified embodiment 2, FIG. 9 is a conceptual diagram showing battery characteristics in modified embodiment 3, FIG. 10 is a conceptual diagram showing battery characteristics in modified embodiment 4, FIG. 11 is a conceptual diagram showing battery characteristics in modified embodiment 5, FIG. 12 is a conceptual diagram showing battery characteristics in modified embodiment 6, FIG. 13 is a conceptual diagram showing battery characteristics in modified embodiment 7, FIG. 14 is a conceptual diagram showing the configuration of a deterioration level determination system in embodiment 2, and FIG. 15 is a conceptual diagram showing a method for determining the deterioration level of a secondary battery in modified embodiment 8. 16 is a flow chart showing a method for determining the deterioration level of a secondary battery in modified embodiment 9; FIG. 17 is a flow chart showing a method for determining the deterioration level of a secondary battery in modified embodiment 10; FIG. 18 is a conceptual diagram showing battery characteristics in modified embodiment 11; FIG. 19 is a flow chart showing a method for determining the deterioration level of a secondary battery in embodiment 3; FIG. 20 is a flow chart showing a method for determining the deterioration level of a secondary battery in modified embodiment 12; FIG. 23 is a flow diagram showing a method for determining the degree of deterioration of a secondary battery in embodiment 5; FIG. 24 is a conceptual diagram showing the configuration of a deterioration degree determination system in embodiment 6; FIG. 25 is a conceptual diagram showing the configuration of a deterioration degree determination system in embodiment 7; FIG. 26 is a conceptual diagram showing battery characteristics in embodiment 7; FIG. 27 is a conceptual diagram showing the configuration of a deterioration degree determination system in modified embodiment 13; FIG. 28 is a conceptual diagram showing the configuration of a deterioration degree determination system in embodiment 8;FIG. 31 is a conceptual diagram showing battery characteristics in Modified Example 15; FIG. 32 is a conceptual diagram showing an SOC-OCV curve of a secondary battery in Embodiment 9; FIG. 33 is a flow diagram showing a method for determining the degree of deterioration of a secondary battery in Embodiment 9; FIG. 34 is a conceptual diagram showing (a) a discharge curve of a secondary battery and (b) a charge curve of a secondary battery in Embodiment 9; and FIG. 35 is a flow diagram showing a method for determining the degree of deterioration of a secondary battery in Embodiment 10. 36 is a conceptual diagram showing an SOC-OCV curve of a secondary battery in embodiment 11, FIG. 37 is a flow diagram showing a method for determining the deterioration level of a secondary battery in embodiment 12, FIG. 38 is a conceptual diagram showing (a) a discharge curve of a secondary battery and (b) another discharge curve of a secondary battery in embodiment 12, FIG. 39 is a conceptual diagram showing an example of an estimation result in embodiment 13, FIG. 40 is a conceptual diagram showing the configuration of a deterioration level determination device in embodiment 14, and FIG. 41 is a flow diagram showing a method for determining the deterioration level of a secondary battery in embodiment 14.

[0017] (Embodiment 1) An embodiment of a server for the deterioration level determination system for a secondary battery will be described with reference to FIGS. 1 to 6. In this specification, the server for the deterioration level determination system is also referred to as a "server." As shown in FIG. 1 , the server 1 of this embodiment 1 is a server 1 for a deterioration level determination system 100 for determining the deterioration level of a secondary battery 2. The server 1 includes an estimation formula storage unit 52 and an update unit 8. The estimation formula storage unit 52 stores an estimation formula for determining the deterioration level based on battery characteristics relating to the transition of the battery state of the secondary battery 2 over a predetermined voltage range or battery characteristic-related values ​​relating to the battery characteristics. The update unit 8 updates the estimation formula stored in the estimation formula storage unit 52 based on battery characteristics relating to the transition of the battery state of the secondary battery 2 acquired by discharging the secondary battery 2 in an external terminal 9.

[0018] A deterioration level determination system 100 including the server 1 of the first embodiment will be described in detail below. As shown in FIG. 1 , the deterioration level determination system 100 is configured by connecting the server 1 and an external terminal 9 via a communication network 200. The server 1 is made up of a computing device. For example, the server 1 can be configured from a single computer or multiple computers. Multiple external terminals 9 can be provided. For example, external terminals can be located at various base sales offices, and the server 1 can be located at one management center, and these can be connected via the communication network 200. The communication network can be a dedicated line, or an existing network such as the Internet or a telephone line can be used.

[0019] In the deterioration level determination system 100 shown in FIG. 1 , the types of secondary batteries 21-26 whose deterioration levels are to be determined are not limited, and known secondary batteries such as nickel-metal hydride batteries and lithium-ion batteries can be used. The secondary batteries 21-26 may have a single cell or multiple cells. In the first embodiment, as shown in FIG. 2( a), the secondary batteries 21-26 form secondary battery modules that are individually detachable modules in the assembled battery 20. While the number of secondary batteries in the assembled battery 20 is not particularly limited, in the first embodiment, six secondary batteries are used, and the secondary batteries 21-26 are connected in series. Alternatively, the secondary batteries 21-26 may be connected in parallel. The assembled battery 20 is then installed in a vehicle 900 as a battery, as shown in FIG. 2( b).

[0020] Next, a description will be given of the server 1. As shown in FIG. 1, in the first embodiment, the server 1 includes a storage unit 5, a calculation unit 6, an update unit 8, and a communication unit 10.

[0021] The storage unit 5 shown in FIG. 1 is made of nonvolatile memory and includes a correspondence relationship storage unit 51 and an estimation formula storage unit 52. In the first embodiment, the correspondence relationship between battery characteristics and total capacity is stored in the correspondence relationship storage unit 51. The form of the correspondence relationship is not particularly limited and may be in the form of, for example, a calculation formula, a map, a graph, a table, or the like. The correspondence relationship may be created by machine learning using a secondary battery under test, based on actual measurements obtained by performing an accelerated degradation test using a secondary battery under test, or by a calculation formula that logically derives the correspondence relationship between battery characteristics and total capacity in a predetermined voltage range using a secondary battery model. The correspondence relationship stored in the correspondence relationship storage unit 51 is set as appropriate according to the battery characteristics acquired by a battery characteristics acquisition unit 63 (described later).

[0022] The total capacity may be the capacity from a fully discharged state to a fully charged state during charging. Alternatively, the total capacity may be the capacity from a fully charged state to a fully discharged state during discharging. Here, the fully discharged state may be an effective fully discharged state defined by a system, such as a vehicle, in which the secondary battery 2 is installed, or may be a state in which the secondary battery 2 has reached a lower limit voltage defined by a user of the deterioration level determination system 100. Furthermore, the fully charged state may be an effective fully charged state defined by a system, such as a vehicle, or may be a state in which the secondary battery 2 has reached an upper limit voltage defined by the user.

[0023] 1 prestores a battery characteristic acquisition criterion, which is a criterion for determining whether or not it is necessary to acquire battery characteristics of the secondary battery 2 and is used in a necessity determination unit 60 described later, a possibility determination criterion, which is a criterion for determining whether or not it is possible to determine the degree of deterioration of the secondary battery 2 and is used in a possibility determination unit 62 described later, and an estimation formula for determining the degree of deterioration, which is used in a deterioration degree determination unit 65 described later. The criterion and the estimation formula are appropriately set according to the manner of determination in the necessity determination unit 60, the possibility determination unit 62, and the deterioration degree determination unit 65, respectively. In the first embodiment, a plurality of estimation formulas are set so that the degree of deterioration can be determined in five stages.

[0024] The calculation unit 6 shown in FIG. 1 is made up of a predetermined calculation device, and includes a necessity determination unit 60, a battery information acquisition unit 61, a possibility determination unit 62, a battery characteristics acquisition unit 63, a capacity estimation unit 64 as an estimation unit, and a deterioration degree determination unit 65.

[0025] 1 determines whether or not it is necessary to acquire battery characteristics for each secondary battery 2 based on a comparison result between battery information including information about the secondary battery 2 and the battery characteristic acquisition criteria stored in the estimation formula storage unit 52. In the first embodiment, the result of a deterioration level determination by the possibility determination unit 62 (described later) is used as the battery characteristic acquisition criteria, and the necessity determination unit 60 determines that acquisition of battery characteristics is necessary for a secondary battery whose deterioration level is determined by the possibility determination unit 62 to be not possible based on the possibility determination criteria. Note that the timing at which the necessity determination unit 60 performs the necessity determination is not limited, and may be performed every time the possibility determination unit 62 performs a possibility determination, may be performed when the number of possibility determinations by the possibility determination unit 62 reaches a predetermined number, may be performed after a predetermined time has elapsed since the previous necessity determination, or may be a combination of these.

[0026] 1 acquires battery information, which is information relating to the secondary batteries 21 to 26. The battery information may be history information of the secondary batteries 21 to 26, or alternatively or in addition to this, it may be battery characteristics, which will be described later. In the first embodiment, the battery information acquisition unit 61 acquires the battery characteristics acquired by a battery characteristics acquisition unit 63, which will be described later, as battery information.

[0027] The possibility determination unit 62 shown in FIG. 1 determines whether or not a deterioration level determination can be performed for each of the secondary batteries 21 to 26 based on the battery information acquired by the battery information acquisition unit 61 or the battery information related values ​​calculated from the battery information, and the possibility determination criteria stored in the estimation formula storage unit 52. In the first embodiment, a secondary battery for which the possibility determination unit 62 determines that a deterioration level determination is not possible is outside the range of training data used to define the deterioration level determination criteria in the deterioration level determination unit 65 (described below), and is in an unlearned range. Therefore, for that secondary battery, the current deterioration level determination may not be sufficiently accurate, and therefore the deterioration level determination (described below) is not performed. This allows the deterioration level to be determined for secondary batteries for which sufficient accuracy can be ensured, thereby improving overall determination accuracy.

[0028] The pass / fail judgment criteria used in the pass / fail judgment unit 62 shown in FIG. 1 can be created by machine learning using a test secondary battery, based on test measurements obtained by performing an accelerated degradation test using the test secondary battery or actual measurements acquired from a used secondary battery, or based on a relational equation that logically derives the pass / fail judgment criteria using a secondary battery model. The pass / fail judgment criteria can be expressed as upper and lower limit values, as only upper limit values ​​or only lower limit values, or in the form of a map. For example, as shown in FIG. 4 , the pass / fail judgment criteria can be a predetermined range calculated by machine learning using the correspondence relationship between battery information A and battery information B acquired from the test secondary battery as training data. That is, the pass / fail judgment criteria can be the distance between data with respect to the training data. The distance between data can be determined based on Mahalanobis distance, Euclidean distance, Manhattan distance, Chebyshev distance, or the like.

[0029] In the first embodiment, the possibility determination unit 62 is configured to use a relational expression related to a plurality of pieces of battery information set in advance to perform the possibility determination based on a Mahalanobis distance calculated as a result of comparing the battery information relation value calculated from the battery information acquired by the battery information acquisition unit with the possibility determination criterion. Note that a plurality of possibility determination criteria may be set. That is, after determining whether the first deterioration level determination is possible based on the first possibility determination criterion, the possibility of the second deterioration level determination may be determined based on the second possibility determination criterion for a secondary battery for which the first deterioration level determination is determined to be impossible.

[0030] The battery characteristics acquisition unit 63 acquires the battery characteristics of the secondary batteries 21-26 within a predetermined voltage range. The battery characteristics of the secondary batteries 21-26 can be, for example, characteristics based on the voltage transition or temperature transition of the secondary battery 2 within the predetermined voltage range Vs. The voltage transition can be calculated based on at least one of the following: the range capacity of the secondary batteries 21-26 within the predetermined voltage range; the ratio of the voltage change of the secondary batteries 21-26 relative to the capacity change of the secondary battery 2 within the predetermined voltage range; and the ratio of the voltage change of the secondary batteries 21-26 relative to the elapsed time within the predetermined voltage range. The predetermined voltage range can be a voltage range in which the degree of deterioration of the secondary batteries 21-26 and the transition of their battery state show a correlation. Such voltage ranges can be set based on the type and configuration of the secondary batteries 21-26 or can be derived through machine learning using the secondary batteries. The battery characteristics acquisition unit 63 may acquire the absolute value of the acquired value as the battery characteristics. The predetermined voltage interval Vs for acquiring the battery characteristics of the secondary batteries 21 to 26 can be set for each of the secondary batteries 21 to 26 and can be changed as needed.

[0031] Furthermore, the battery characteristics acquisition unit 63 acquires battery characteristics in a specific voltage range or capacity range for a secondary battery for which the possibility determination unit 62 has determined that the degree of degradation cannot be determined. The voltage range or capacity range is not particularly limited and may be a range corresponding to the full capacity or a range corresponding to a predetermined capacity. The battery characteristics in the specific capacity range are referred to as capacity battery characteristics. For example, the capacity battery characteristics at the full capacity may be characteristics based on the voltage transition or temperature transition of the secondary battery 2 in a voltage range from a fully discharged state to a fully charged state during charging, or in a voltage range from a fully charged state to a fully discharged state during discharging.

[0032] In this embodiment, the discharge voltage characteristic is used as the battery characteristic. As shown in Fig. 3, the discharge voltage characteristic is calculated based on the voltage transition when the secondary battery 2 is discharged to a discharge target voltage VP. The discharge target voltage VP is not particularly limited, but can be a voltage equal to or lower than the lower limit of the normal use range Vn of the voltage value of the secondary battery 2.

[0033] The voltage trend can be calculated based on, for example, at least one of the following: the interval capacity of the secondary battery 2 in a predetermined voltage interval Vs; the ratio of the voltage change of the secondary battery 2 to the capacity change of the secondary battery 2 in the predetermined voltage interval Vs; and the ratio of the voltage change of the secondary battery 2 to the elapsed time in the predetermined voltage interval Vs.

[0034] The predetermined voltage section Vs can be a voltage section in which a correlation is shown between the degree of deterioration of the secondary battery 2 and the transition of the battery state. Such a voltage section Vs can be set based on the type and configuration of the secondary battery 2, or can be derived by machine learning using the secondary battery 2. For example, in the first embodiment, as shown in FIG. 3 , the predetermined voltage section Vs is a section from voltage values ​​V1 to V2. Such a voltage section Vs is a section in which the difference in discharge voltage characteristics becomes significant depending on the degree of deterioration of the secondary battery 2.

[0035] In the first embodiment, the estimation unit includes a capacity estimation unit 64 shown in Fig. 1. In the first embodiment, the capacity estimation unit 64 estimates the total capacity of a secondary battery 2 for which the degradation level determination has been determined to be possible by the possibility determination unit 62, based on the battery characteristics acquired by the battery characteristics acquisition unit 63. The total capacity can be estimated using a prediction model such as a regression equation created based on previously acquired training data, and examples of the model that can be used include linear regression, LASSO regression, Ridge regression, decision tree, and support vector regression.

[0036] 1 determines the degree of deterioration of the secondary battery 2 based on the battery characteristics or battery characteristic-related values. The battery characteristic-related values ​​are values ​​calculated based on the battery characteristics, and in the first embodiment, the estimation result of the capacity estimation unit 64 is used as the battery characteristic-related value. Therefore, in the first embodiment, the deterioration degree determination unit 65 determines the degree of deterioration of the secondary battery 2 based on the estimation result of the capacity estimation unit 64. The determination can be made by comparing the estimation result of the capacity estimation unit 64 with an estimation formula stored in advance in the estimation formula storage unit 52.

[0037] The update unit 8 shown in FIG. 1 is composed of a predetermined calculation device and includes an estimation formula update unit 81. The estimation formula update unit 81 updates the battery characteristic acquisition criteria, i.e., the acceptability determination criteria, and the estimation formula stored in the estimation formula storage unit 52. For a secondary battery whose degradation level is determined to be undeterminable by the acceptability determination unit 62, the charge / discharge control unit 71 charges / discharges the secondary battery to acquire an actual measured value of the total capacity, and the battery characteristic acquisition unit 63 acquires capacity battery characteristics based on the actual measured value of the total capacity. This can be used as additional training data to update the acceptability determination criteria and the estimation formula stored in the estimation formula storage unit 52. This allows the determination criteria to be updated in accordance with changes in the secondary battery over time, thereby maintaining high determination accuracy. The timing at which the estimation formula update unit 81 performs the update is not limited. It may be when the capacity battery characteristics are acquired, when the number of data points for the capacity battery characteristics reaches a predetermined number, after a predetermined time has elapsed since the previous update, or a combination of these.

[0038] The communication unit 10 shown in FIG. 1 is a computing device that can be connected to the communication network 200 via a wired or wireless connection and transmit and receive data, and includes a transmitter 11 and a receiver 12. The transmitter 11 transmits instruction information to the external terminal 9 (described later) that instructs the external terminal 9 to acquire the capacity battery characteristics of the secondary battery 2 based on the determination result of the feasibility determination unit 62. The instruction information may be transmitted when a predetermined number of secondary batteries 2 have been determined by the feasibility determination unit 62 to require the acquisition of capacity battery characteristics. In the first embodiment, the receiver 12 receives from the external terminal 9 the actual measured capacity value as acquired information acquired by the external terminal 9 that received the instruction information. The transmitter 11 and the receiver 12 may be capable of transmitting and receiving all information between the server 1 and the external terminal 9.

[0039] Next, a description will be given of the external terminal 9. As shown in FIG.

[0040] 1 includes a voltage value detection unit 31 and a current value detection unit 32. The voltage value detection unit 31 is made up of a predetermined voltmeter and detects the voltage values ​​of the secondary batteries 21 to 26. The current value detection unit 32 is made up of a predetermined ammeter and detects the value of the current flowing through the secondary batteries 21 to 26. The open circuit voltages of the secondary batteries 21 to 26 are obtained based on the voltage values ​​detected by the voltage value detection unit 31.

[0041] 1 is made up of a rewritable nonvolatile memory, and includes a voltage value storage section 41 and a current value storage section 42. The voltage value storage section 41 stores the voltage value detected by the voltage value detection section 31, and the current value storage section 42 stores the current value detected by the current value detection section 32.

[0042] The control unit 7 shown in Fig. 1 includes a charge / discharge control unit 71. The charge / discharge control unit 71 controls charging and discharging of the secondary battery 2. The charge / discharge control unit 71 is made up of a calculation device capable of executing a predetermined program. Note that charging and discharging by the charge / discharge control unit 71 includes any of the following cases: charging only, discharging only, discharging and then charging, and charging and then discharging.

[0043] 1 is composed of a computing device that is connected to the communication network 200 by wire or wirelessly and is capable of transmitting and receiving data, and has a transmitting unit 91 and a receiving unit 92. The transmitting unit 91 and the receiving unit 92 are capable of transmitting and receiving all information between the external terminal 9 and the server 1. In the first embodiment, the transmitting unit 91 is capable of transmitting each value detected by the detecting unit 3 of the external terminal 9 to the server 1, and the receiving unit 92 is capable of receiving the reference value, the deterioration degree determination result, update information, etc. from the server 1.

[0044] 1 is configured to be able to display various information, such as the results of the deterioration degree determination and update information.

[0045] The flow of the degradation level determination method using the degradation level determination system 100 of the first embodiment will be described below. First, in step S1 shown in FIG. 5, as a preparation step, the secondary batteries 21-26 in the form of modules are removed from the used battery pack 20 shown in FIG. 2A at a base sales office equipped with an external terminal 9. Then, in step S2, the remaining capacity of each of the secondary batteries 21-26 is individually discharged by the charge / discharge control unit 71 using the external terminal 9. As shown in FIG. 3, this discharge continues until the open-circuit voltage reaches a predetermined discharge target voltage VP. If the secondary batteries 21-26 are nickel-metal hydride batteries, they may have a memory effect. However, the memory effect is also simultaneously removed for those secondary batteries 21-26 that have been discharged to the discharge target voltage VP or a voltage close to it.

[0046] Then, in step S2 shown in FIG. 5, the remaining capacity is discharged and the detection unit 3 detects the voltage and current values ​​during discharge, and in step S21, the detection value is transmitted to the server 1 by the transmission unit 91 of the external terminal 9, and the detection value is received by the reception unit 12 of the server 1.

[0047] 5, the battery characteristics acquisition unit 63 of the server 1 acquires the battery characteristics of each of the secondary batteries 21 to 26. In the first embodiment, the battery characteristics acquired are the discharge voltage characteristics described above. As described above, the discharge voltage characteristics are based on the voltage transitions in the predetermined voltage range Vs of each of the secondary batteries 21 to 26 shown in FIG.

[0048] In the first embodiment, as shown in FIG. 3, the battery characteristics acquisition unit 63 acquires the discharge start time T ０ Discharge end T Ｐ１ A voltage-time change is obtained, which indicates the relationship between the voltage change over time and the voltage VA. Then, a differential value at the voltage VA within a predetermined voltage interval Vs, i.e., the slope of the tangent at the voltage VA indicated by reference symbol 21A in the voltage-time change graph shown in FIG. 3, is calculated, and this is defined as the discharge voltage characteristic of the first secondary battery 21. Similarly, as shown in FIG. 3, a voltage-time change is obtained as the voltage transition for the second secondary battery 22, and a differential value at the voltage VA within the predetermined voltage interval Vs indicated by reference symbol 22A is calculated, and this is defined as the discharge voltage characteristic of the second secondary battery 22. Similarly, a voltage-time change is obtained as the voltage transition for the third to sixth secondary batteries 23 to 26, and a differential value at the voltage VA is calculated to define the respective discharge voltage characteristics.

[0049] In the first embodiment, the voltage change over time is acquired as the voltage transition, and the differential value of the voltage VA within the predetermined voltage interval Vs is used as the discharge voltage characteristic. However, instead of this, the rate of voltage change between two points in the voltage change over time derived as the voltage transition, i.e., the slope of the line passing through the two points in the voltage change over time graph, may be calculated and used as the discharge voltage characteristic. For example, the start time T of the voltage interval Vs may be calculated as the two points in the voltage change over time of the first secondary battery 21 shown in FIG. Ａ１ and the end time T Ａ２ The above two points are adopted, and the same two points can also be adopted for the other secondary batteries 22 to 26.

[0050] 5, the battery information acquisition unit 61 of the server 1 acquires the battery characteristics acquired by the battery characteristics acquisition unit 63 as battery information. After that, in step S5, the feasibility determination unit 62 determines whether the degree of deterioration can be determined. Specifically, the feasibility determination unit 62 determines whether the data distance between the feasibility determination criterion stored in the estimation formula storage unit 52 and the battery information relation value calculated from the acquired battery information is within a predetermined range, i.e., whether the battery information relation value is within the feasibility determination criterion shown in FIG.

[0051] If the acquired battery information does not fall within the acceptability criteria, acceptability determination unit 62 determines that it is not possible to determine the degree of deterioration, and proceeds to No in step S5 shown in Fig. 5. Then, in step S6, for those secondary batteries 21 to 26 for which it is not possible to determine the degree of deterioration, the process proceeds to step S9 described below without determining the degree of deterioration.

[0052] 5 , if the acquired battery information falls within the determination criteria, the determination unit 62 determines that the degree of deterioration can be determined, and the process proceeds to "Yes" in step S5. Then, in step S7, the capacity estimation unit 64 estimates the total capacity of each of the secondary batteries 21 to 26 for which it has been determined that the degree of deterioration can be determined, based on the battery characteristics acquired by the battery characteristics acquisition unit 63. In the first embodiment, the capacity estimation unit 64 estimates the total capacity of each of the secondary batteries 21 to 26 from the discharge voltage characteristics acquired by the battery characteristics acquisition unit 63, based on the correspondence between the discharge voltage characteristics and the total capacity based on the prediction model stored in the correspondence storage unit 51.

[0053] 5, the deterioration level determination unit 65 determines the deterioration levels of the secondary batteries 21 to 26 based on the total capacity estimated by the capacity estimation unit 64. Then, in step S81, the transmission unit 11 of the server 1 transmits the deterioration level determination result to the external terminal 9. The process proceeds to step S82, where the reception unit 92 of the external terminal 9 receives the deterioration level determination result and displays it on the display unit 93. The process then proceeds to step S9, where the current deterioration level determination is completed.

[0054] Then, the process proceeds to symbol A shown in Fig. 5, where in step S10 the necessity determination unit 60 determines whether or not it is necessary to acquire the capacity battery characteristics. In the first embodiment, for a secondary battery for which the possibility determination unit 62 determines in step S5 that it is not possible to determine the degree of degradation, it is determined that it is necessary to acquire the capacity battery characteristics, and for a secondary battery for which the degree of degradation determination is possible, it is determined that it is not necessary to acquire the capacity battery characteristics. If it is determined in step S10 that there is no secondary battery for which it is determined that it is necessary to acquire the capacity battery characteristics, the process proceeds to No in step S10, and this control flow ends. On the other hand, if it is determined in step S10 that there is a secondary battery for which it is determined that it is necessary to acquire the capacity battery characteristics, the process proceeds to Yes in step S10.

[0055] Then, proceed to step S101 shown in Figure 5, and send instruction information to the external terminal 9 instructing it to acquire the capacity battery characteristics of the secondary battery 2 for which the transmission unit 11 of the server 1 has determined that acquisition of the capacity battery characteristics is necessary, and receive the instruction information by the receiving unit 92 of the external terminal 9.

[0056] 5, for the secondary battery 2 for which it is determined based on the instruction information that acquisition of the capacity battery characteristics is required, the charge / discharge control unit 71 performs charging / discharging to measure the capacity and obtain an actual measurement value. After the measurement, the transmitter 91 of the external terminal 9 transmits the actual measurement value to the server 1 in step S111, and the receiver 12 of the server 1 receives the actual measurement value. Then, in step S112, the battery characteristics acquisition unit 63 acquires the capacity battery characteristics based on the actual measurement value. In step S12, the estimation formula update unit 81 updates the estimation formula stored in the estimation formula storage unit 52 using the capacity battery characteristics as additional training data. In this embodiment, the pass / fail determination criteria, i.e., the battery characteristics acquisition criteria, are also updated. Both of these criteria values ​​are used for subsequent degradation level determinations.

[0057] Next, a method for manufacturing a rebuilt battery pack 20 by assembling secondary batteries 2 constituting modules removed from a used battery pack 20 into a new battery pack 20 will be described below. First, in step S13 shown in FIG. 6 , multiple secondary batteries 2 removed from the battery pack 20 are prepared. Then, in step S14, the battery characteristics of each secondary battery 2 are acquired. The battery characteristics can be acquired in the same manner as when acquiring battery characteristics in the deterioration level determination system 100 of the first embodiment. Then, in step S15, the secondary batteries 2 are ranked based on the battery characteristics or battery characteristic-related values ​​calculated based on the battery characteristics. In the first embodiment, the total capacity of the secondary batteries 2 is estimated based on the battery characteristics as the battery characteristic-related value, and the secondary batteries 2 are ranked based on whether the absolute value of the deterioration level of the secondary batteries 2 calculated from the total capacity is within a predetermined range. Then, in the first embodiment, the absolute value of the deterioration level is divided into five predetermined ranges, and the absolute value of the deterioration level is ranked A, B, C, D, and E in order of decreasing absolute value. Note that the ranking criteria can be set as appropriate.

[0058] Next, in step S16 shown in FIG. 6 , the secondary batteries 21 to 26 are sorted based on their ranks. In this embodiment, the secondary batteries 21 to 26 are sorted by rank. As a result, secondary batteries 2 belonging to the same rank have the same degree of deterioration. Then, in step S17, secondary batteries 2 of the same rank are combined to assemble a battery pack 20 to create a rebuilt product. As a result, the absolute values ​​of the degrees of deterioration of the secondary batteries 2 included in the rebuilt battery pack 20 are similar, and the difference in the degrees of deterioration can be set to a predetermined reference value or less. The reference value for the difference in the degrees of deterioration can be set appropriately depending on the ranking criteria. In this embodiment, the battery pack 20 is created using secondary batteries 2 of the same rank. However, this is not limited to this, and the battery pack 20 may be created within a predetermined range of ranks. For example, the battery pack 20 may be created from secondary batteries 2 belonging to ranks A and B. Secondary batteries 2 ranked E, the lowest rank, may be discarded as unusable or disassembled for recycling.

[0059] 6, supplementary charging is then performed on each assembled battery 20. As a result, the secondary batteries 21 to 26 become usable as the assembled battery 20.

[0060] Next, a detailed description will be given of the effects of the deterioration level determination system 100 and the server 1 of the present embodiment 1. In the server 1 for the secondary battery deterioration level determination system of the present embodiment 1, the estimation formula for determining the deterioration level is configured to be updated based on the capacity battery characteristics relating to the transition of the battery state of the secondary battery 2 acquired by discharging the secondary battery 2. This enables the estimation formula to follow the deterioration trend of the secondary battery 2, which changes over time, and makes it possible to determine the deterioration level of the secondary battery with high accuracy.

[0061] In the first embodiment, the server 1 includes an estimation formula storage unit 52 that stores a battery characteristic acquisition standard, which is a standard for determining whether or not it is necessary to acquire the capacity battery characteristic of the secondary battery 2, a necessity determination unit 60 that determines whether or not it is necessary to acquire the capacity battery characteristic for each secondary battery 2 based on a comparison result between battery information, including information about the secondary battery 2, and the battery characteristic acquisition standard, a transmitter 11 that transmits instruction information to an external terminal instructing the external terminal 9 to acquire the capacity battery characteristic of the secondary battery 2 based on the determination result of the necessity determination unit 60, and a receiver 12 that receives from the external terminal 9 an actual measurement value of capacity as acquisition information acquired by the external terminal 9 that received the instruction information. The update unit 8 updates the estimation formula using the capacity battery characteristic based on the actual measurement value received by the receiver 12. This allows the server 1 to determine whether or not it is necessary to acquire the capacity battery characteristic of the secondary battery 2, and then update the estimation formula using the capacity battery characteristic, thereby enabling highly accurate determination of the degree of deterioration of the secondary battery.

[0062] Furthermore, in the first embodiment, the update unit 8 is configured to update the battery characteristic acquisition criteria using the capacity battery characteristics based on the actual measurement values ​​received by the receiving unit 12. This allows the battery characteristic acquisition criteria to follow the tendency of deterioration of the secondary battery 2, which changes over time, and enables the degree of deterioration of the secondary battery to be determined with high accuracy.

[0063] In addition, in the first embodiment, the necessity determining unit 60 is specified to determine whether or not the deterioration level of the secondary battery 2 can be determined based on the battery characteristics acquisition criteria, and to determine that it is necessary to acquire the capacity battery characteristics of the secondary battery for which it is determined that the deterioration level cannot be determined. This makes it possible to acquire the capacity battery characteristics of the secondary battery for which it is determined that the deterioration level cannot be determined, and update the estimation formula, thereby making it possible to determine the deterioration level of the secondary battery with high accuracy.

[0064] In addition, in the first embodiment, the transmitter 11 of the server 1 transmits the instruction information each time the necessity determination unit 60 determines that acquisition of the capacity battery characteristics is necessary. However, in the first modified embodiment, as shown in FIG. 7 , if it is determined in step S10 that there is a secondary battery for which acquisition of the capacity battery characteristics is determined to be necessary, the process proceeds from Yes in step S10 to step S102, where the count number of a counter (not shown) provided in the server 1 is incremented. If the transmitter 11 determines in step S103 that the count number has not reached a predetermined value, the process proceeds to No in step S103, where the flow ends without transmitting the instruction information to the external terminal 9. On the other hand, if the transmitter 11 determines in step S103 that the count number has reached the predetermined value, the process proceeds from Yes in step S103 to step S101, where the process executes steps S101 and subsequent steps as in the first embodiment.

[0065] According to the first modified embodiment, the transmitter 11 of the server 1 transmits the instruction information when the number of secondary batteries 2 for which it has been determined by the necessity determiner 60 that acquisition of capacity battery characteristics is necessary reaches a predetermined number. This prevents the estimation formula from being updated too frequently and allows updates to be performed at an appropriate frequency, thereby preventing the calculation load on the server 1 from becoming excessively large while maintaining high accuracy in determining the degree of deterioration.

[0066] Furthermore, in Modification 2, instead of the counter of Modification 1, the server 1 may have a time measurement unit (not shown). In Modification 2, the time measurement unit starts time measurement at the time of update. Then, in the control flow of Modification 2, as shown in FIG. 8 , the process proceeds from symbol A to step S91, where the time measurement unit of the server 1 determines whether a predetermined time has elapsed since the previous update. If it is determined that the predetermined time has not elapsed, the process proceeds to No in step S91, and the process ends without determining whether or not the capacity battery characteristics need to be acquired. On the other hand, if it is determined in step S91 that the predetermined time has elapsed, the process proceeds from Yes in step S91 to step S10, and steps S10 and thereafter are performed as in the first embodiment. Then, after step S12, the time measurement by the time measurement unit is reset and restarted in step S121.

[0067] According to the second modified embodiment, the necessity determining unit 60 determines whether or not it is necessary to acquire the capacity battery characteristics when a predetermined time has elapsed since the previous update performed by the updating unit 8. This prevents the estimation formula from being updated too frequently, and allows updates to be performed at an appropriate frequency, thereby preventing the calculation load on the server 1 from becoming excessively large while maintaining high accuracy in determining the degree of deterioration.

[0068] In the first embodiment, the server 1 further includes a deterioration level determination unit that compares the estimation formula with the battery characteristics or the battery characteristic-related value and determines the deterioration level of the secondary battery based on the comparison result, and the transmission unit 11 of the server 1 transmits the determination result by the deterioration level determination unit to the external terminal 9. This reduces the calculation load on the external terminal 9 and the processing power required for the external terminal 9. This allows the external terminal 9 to be made smaller and its manufacturing cost to be reduced, contributing to the construction of a deterioration level determination system 100 using a large number of external terminals 9.

[0069] Furthermore, the deterioration level determination system 100 of the first embodiment determines the deterioration level of a secondary battery based on battery characteristics or battery characteristic-related values ​​related to voltage transitions in a predetermined voltage range obtained from the secondary battery 2. Therefore, the deterioration level can be determined through a simple process. Furthermore, by setting a voltage range in which a high correlation exists between the voltage transitions of the secondary battery 2 and the deterioration level as the voltage range for obtaining the battery characteristics of the secondary battery 2, the deterioration level of the secondary battery 2 can be determined with high accuracy. Then, before determining the deterioration level of each secondary battery 2, it is determined whether or not it is possible to determine the deterioration level, and then the deterioration level is determined for each secondary battery 2 for which it is determined that the deterioration level can be determined. Therefore, by determining the deterioration level for secondary batteries 2 for which sufficient determination accuracy can be ensured, the overall determination accuracy can be improved.

[0070] Furthermore, in the deterioration level determination system 100 of the first embodiment, the possibility determination unit 62 performs the possibility determination based on the result of comparing the battery information relation value calculated from the battery information acquired by the battery information acquisition unit 61 with the possibility determination criterion using a relational expression related to a plurality of pieces of battery information that have been set in advance. In this way, the determination accuracy can be improved by appropriately adjusting the relational expression.

[0071] The deterioration level determination system 100 of the first embodiment can provide a battery pack 20 including a plurality of secondary batteries 2 with usage histories, in which battery characteristics relating to the transition of the battery state in a predetermined voltage range Vs of the secondary batteries 2 or battery characteristic-related values ​​calculated based on the battery characteristics are within a predetermined range. Such a rebuilt battery pack 20 can provide a battery pack 20 with small variations in battery characteristics. By setting a voltage range Vs in which the voltage transition of the secondary batteries 2 and the degree of deterioration are highly correlated as the voltage range Vs for acquiring the battery characteristics of the secondary batteries 2, the variation in the degree of deterioration of the secondary batteries 2 included in the battery pack 20 can be reduced, thereby enabling the battery pack 20 to have a longer life and improved quality.

[0072] In the first embodiment, the capacity estimation unit 64 estimates the total capacity of the secondary batteries 21 to 26 from the battery characteristics acquired by the battery characteristics acquisition unit 63, and the deterioration level determination unit 65 determines the deterioration level of the secondary batteries 21 to 26 based on the estimation result. However, instead of this, the deterioration level determination unit 65 may determine the deterioration level of the secondary batteries 21 to 26 without estimating the total capacity based on the battery characteristics acquired by the battery characteristics acquisition unit 63. Also, the battery characteristics acquisition unit 63 may acquire the absolute value of the acquired value as the battery characteristic, and the deterioration level determination unit 65 may determine the deterioration level based on the absolute value. Also, the deterioration level determination unit 65 may determine the deterioration level of the secondary batteries 21 to 26 based on the difference between the battery characteristics acquired by the battery characteristics acquisition unit 63.

[0073] In the first embodiment, the secondary batteries 21 to 26 are classified and assembled into the battery pack 20 so that the degree of deterioration of the secondary batteries 21 to 26 falls within a predetermined range. However, the secondary batteries 21 to 26 may also be classified and assembled into the battery pack 20 so that the degree of deterioration of the secondary batteries 21 to 26 and the difference between the degrees of deterioration fall within a predetermined range.

[0074] Furthermore, in the first embodiment, the battery characteristics are discharge voltage characteristics based on voltage transitions in predetermined voltage intervals Vs1 and Vs2 of the secondary batteries 21 to 26. If the secondary batteries 21 to 26 are nickel-metal hydride batteries, they may be discharged to eliminate memory effects when they are reused, and by acquiring the discharge voltage characteristics during this discharge, the work process for reusing the secondary batteries 21 to 26 can be simplified.

[0075] In the first embodiment, the discharge voltage characteristics are calculated based on the voltage transition during discharge of the secondary battery 2. However, instead of or in addition to this, the discharge voltage characteristics may be calculated based on the voltage transition during voltage relaxation, in which the secondary battery 2 is discharged to the discharge target voltage VP and the discharge is stopped, and then the discharge voltage returns to the open circuit voltage. For example, as shown in the third modified example in FIG. 9, the discharge voltage characteristics may be calculated based on the voltage transition during voltage relaxation, in which the first secondary battery 21 is discharged to the discharge target voltage VP and the discharge is stopped, and then the discharge voltage is ... discharge voltage characteristics are calculated based on the voltage transition during voltage relaxation, in which the discharge voltage characteristics are calculated based on the voltage transition during voltage relaxation, in which the discharge voltage characteristics are calculated based on the voltage transition during voltage relaxation, in which the discharge voltage characteristics are calculated based on the voltage transition during Ｐ１Based on the voltage transition in the predetermined voltage section Vs in the subsequent voltage relaxation, a differential value at the predetermined voltage VA indicated by the reference symbol 21A can be calculated to obtain the discharge voltage characteristic. Ｐ２ Based on the voltage transition in the predetermined voltage section Vs during subsequent voltage relaxation, a differential value at the predetermined voltage VA indicated by the reference symbol 22A can be calculated as the discharge voltage characteristic, and similarly, discharge voltage characteristics based on the voltage transition in the predetermined voltage section Vs during voltage relaxation can be obtained for the other secondary batteries 23 to 26 (not shown). In this case, too, the same effects as those of the first embodiment can be achieved.

[0076] Furthermore, in the first embodiment, a capacity estimation unit 64 is provided that estimates the total capacity of the secondary battery using the battery characteristics acquired by the battery characteristics acquisition unit 63 as battery characteristic-related values, and a deterioration level determination unit 65 determines the deterioration levels of the secondary batteries 21 to 26 based on the estimation results of the capacity estimation unit 64. This makes it possible to detect the deterioration levels of the secondary batteries 21 to 26 with high accuracy.

[0077] In the first embodiment, the voltage transition is determined by calculating the rate of voltage change of the secondary battery 2 with respect to the elapsed time in a predetermined voltage section Vs, i.e., the differential value of the voltage change over time, and this is used as the discharge voltage characteristic. This allows the degree of deterioration of the secondary battery 2 to be determined easily and with high accuracy.

[0078] Note that, instead of or in addition to calculating the rate of voltage change of the secondary battery 2 with respect to the elapsed time in a predetermined voltage interval Vs as the voltage transition, the battery characteristics acquisition unit 63 may calculate the amount of capacity change of each secondary battery 21-26 in the predetermined voltage interval Vs as an interval capacity Qp, and use this as the discharge voltage characteristic, as in Variation 4 shown in Figure 10. The interval capacity Qp can be calculated from the current value flowing through the secondary batteries 21-26 in the voltage interval Vs detected by the current value detection unit 32 and the time during which the current flowed. In this case as well, the degree of deterioration of the secondary battery 2 can be determined accurately and simply based on the discharge voltage characteristic.

[0079] In addition, the entire period T ０ ~T Ｐ１ , T ０ ~TＰ２ 10 may be calculated as the capacity of the secondary battery 2, and a capacity ratio may be calculated as the ratio of the section capacity Qp to the total charge / discharge capacity Qt, and this may be used as the discharge voltage characteristic. Alternatively, instead of the total charge / discharge capacity Qt, a specific section capacity Qt' may be calculated as the capacity of a specific voltage section including the voltage section for calculating the battery characteristics, and a capacity ratio may be calculated as the ratio of the section capacity Qp to the specific section capacity Qt', and this may be used as the discharge voltage characteristic. In this case as well, the degree of deterioration of the secondary battery 2 can be determined accurately and simply based on the discharge voltage characteristic.

[0080] In addition, in the first embodiment, the voltage time change is acquired as the voltage transition and the differential value of the voltage VA within a predetermined voltage section Vs is used as the discharge voltage characteristic. However, instead of this, as in the fifth modified embodiment shown in FIG. 11, the capacity Q at the start of discharge is acquired as the voltage transition. ０ From the capacity Q at the end of discharge ｐ１ Alternatively, a voltage-capacity change indicating the relationship between the voltage change and the capacity up to 1000 kJ / s may be acquired. Then, a differential value at the voltage VA within a predetermined voltage interval Vs, i.e., the slope of the tangent at the voltage VA in the voltage-capacity change graph, may be calculated and used as the discharge voltage characteristic of the first secondary battery 21. In this case, the same effects as those of the first embodiment can be achieved.

[0081] In this embodiment 1, the battery characteristics are calculated and acquired in the battery characteristics acquisition unit 63 provided in the deterioration level determination system 100, but instead, the deterioration level determination system 100 may have an external input unit, and the battery characteristics may be calculated using an externally provided arithmetic device, and the battery characteristics may be input to the battery characteristics acquisition unit 63 via the external input unit, so that the battery characteristics acquisition unit 63 acquires the battery characteristics.

[0082] In the first embodiment, the discharge voltage characteristic is used as the battery characteristic, but the battery characteristic may also include a charge voltage characteristic based on the voltage transition when the secondary batteries 21 to 26 are charged to a predetermined charge target voltage VQ, as in modified embodiment 6 shown in Fig. 12. The charge target voltage VQ is not particularly limited, but in the first embodiment, it is set to a value that is greater than the lower limit value and smaller than the upper limit value of the normal use range Vn. The other components are the same as in the first embodiment.

[0083] In the sixth modified embodiment, the calculation of the voltage transition during charging can be performed in the same manner as the calculation of the voltage transition in the discharge voltage characteristic in the first embodiment and each modified embodiment, and the calculated result is used as the charge voltage characteristic. That is, as shown in FIG. 12, Ｐ１ , T Ｐ２ From the start of charging to the end of charging T Ｑ１ , T Ｑ２ The voltage-time change is acquired, which indicates the relationship between the voltage change over time and the voltage VB. Then, the differential value at the voltage VB within a predetermined voltage interval VsB, i.e., the slope of the tangent at the voltage VB indicated by reference symbol 21B in the voltage-time change graph shown in FIG. 12, is calculated, and this is defined as the charge voltage characteristic of the first secondary battery 21. Similarly, as shown in FIG. 12, the voltage-time change is acquired as the voltage transition for the second secondary battery 22, and the differential value at the voltage VB within the predetermined voltage interval Vs indicated by reference symbol 22B is calculated, and this is defined as the discharge voltage characteristic of the second secondary battery 22. Similarly, the voltage-time change is acquired as the voltage transition for the third to sixth secondary batteries 23 to 26, and the differential value at the voltage VB is calculated to define the respective charge voltage characteristics. The predetermined voltage interval VsB is the interval between voltage values ​​V3 and V4, where significant differences in the charge voltage characteristics occur depending on the degree of deterioration of the secondary battery 2.

[0084] The charge voltage characteristic may be calculated as the ratio of voltage change between two points, ie, the start time TB11, TB21 and the end time TB12, TB22, of a predetermined voltage section VsB, or as the section capacity Qp in the voltage section VsB, or as the total section T Ｐ１ ~T Ｑ１ , T Ｐ２ ~TＱ２ Alternatively, instead of the total charge / discharge capacity QT when charged to the charge target voltage VQ, a specific section capacity QT', which is the capacity of a specific voltage section including the voltage section for calculating the battery characteristics, may be calculated, and the capacity ratio of the section capacity Qp to the specific section capacity QT' may be calculated and used as the charge voltage characteristics.

[0085] In the sixth modified embodiment, the battery characteristics acquisition unit 63 acquires both the discharge voltage characteristics and the charge voltage characteristics, and the capacity estimation unit 64 estimates the total capacity of the secondary battery 2 based on these characteristics. This makes it possible to determine the degree of deterioration of the secondary battery 2 with even greater accuracy.

[0086] When manufacturing a rebuilt battery pack 20 using the deterioration level determination system 100 of this modified embodiment 6, each secondary battery 2 is charged before assembling the battery pack 20, so there is no need to supplementarily charge the battery pack 20 in step S18 in Figure 6.

[0087] Furthermore, in this modified embodiment 6, the battery characteristics acquisition unit 63 acquires the discharge voltage characteristics and then the charge voltage characteristics by discharging the secondary battery 2 and then charging it, but this is not limited to this, and the battery characteristics acquisition unit 63 may acquire the charge voltage characteristics and then the discharge voltage characteristics by charging the secondary battery and then discharging it.

[0088] Furthermore, in the sixth modified example, the battery characteristic acquisition unit 63 acquires both the discharge voltage characteristic and the charge voltage characteristic. However, instead, it may acquire only the charge voltage characteristic. In this case, the determination accuracy may be inferior to when both the discharge voltage characteristic and the charge voltage characteristic are acquired. On the other hand, if the secondary batteries 21-26 are nickel-metal hydride batteries, memory effect may occur. When only the discharge voltage characteristic is acquired, the memory effect may cause variations in the voltage transition of the discharge voltage characteristic, which may hinder the improvement of the determination accuracy. However, when only the charge voltage characteristic is acquired after the remaining capacity is discharged, the charge voltage characteristic is acquired after the memory effect has been eliminated, and therefore the effect of the memory effect is small, and therefore the determination accuracy can be expected to be improved.

[0089] Furthermore, the charge voltage characteristic in this modified example 6 may be calculated based on the voltage transition during voltage relaxation, in which the battery is charged to a predetermined charge target voltage VQ, the charging is stopped, and then the battery returns to the open circuit voltage, as in the case of the discharge voltage characteristic in the first embodiment. For example, as in modified example 7 shown in FIG. 13 , the time T Ｑ１ Based on the voltage transition in the predetermined voltage section VsB in the subsequent voltage relaxation, a differential value at the predetermined voltage VB indicated by the reference symbol 21B may be calculated as the charging voltage characteristic. Ｑ２ Based on the voltage transition in the predetermined voltage section VsB during the subsequent voltage relaxation, a differential value at the predetermined voltage VB indicated by the reference symbol 22B may be calculated as the charging voltage characteristic. In this case, the same effects as those of the first embodiment can be achieved.

[0090] As described above, according to the above aspect, it is possible to provide a secondary battery deterioration level determination system 100 that can determine the deterioration level of the secondary battery 2 with high accuracy.

[0091] In the sixth modified example, similar to the modified example of the first embodiment, the deterioration level determination unit 65 may determine the deterioration level of the secondary battery 2 based on the battery characteristics acquired by the battery characteristics acquisition unit 63 without estimating the total capacity. Alternatively, the battery characteristics acquisition unit 63 may acquire the absolute value of the acquired value as the battery characteristic, and the deterioration level determination unit 65 may determine the deterioration level based on the absolute value. Alternatively, the deterioration level determination unit 65 may determine the deterioration level of the secondary battery 2 based on the difference between the battery characteristics acquired by the battery characteristics acquisition unit 63. Alternatively, the secondary batteries 2 may be classified into classes so that the deterioration levels of the secondary batteries 2 and the difference between the deterioration levels are within a predetermined range, and the assembled battery 20 may be assembled.

[0092] (Embodiment 2) In the deterioration degree determination system 100 of embodiment 1, as shown in Fig. 1, the server 1 includes a memory unit 5, a calculation unit 6, an update unit 8, and a communication unit 10, and the external terminal 9 includes a detection unit 3, a storage unit 4, a control unit 7, a communication unit 90, and a display unit 93, but the external terminal 9 may include some of the components included in the server 1. In the deterioration degree determination system 100 of embodiment 2, as shown in Fig. 14, the server 1 includes an update unit 8 and a communication unit 10, and the external terminal 9 includes a detection unit 3, a storage unit 4, a memory unit 5, a calculation unit 6, a control unit 7, a communication unit 90, and a display unit 93.

[0093] In the second embodiment, the transmitting unit 91 of the external terminal 9 shown in FIG. 14 transmits the capacity battery characteristics acquired by the battery characteristics acquisition unit 63 in the calculation unit 6 to the server 1. The receiving unit 12 of the server 1 receives the capacity battery characteristics transmitted from the external terminal 9, and the estimation formula update unit 81 in the server 1 creates update information. The transmitting unit 11 of the server 1 transmits the update information by the estimation formula update unit 81 to the external terminal 9. The receiving unit 92 of the external terminal 9 receives the update information transmitted from the server 1 and updates the estimation formula stored in the estimation formula storage unit 52 of the external terminal 9. Furthermore, the reference value stored in the estimation formula storage unit 52 of the external terminal 9 may be updated based on the update information. Note that other configurations are similar to those in the first embodiment, and the same reference numerals as those in the first embodiment are used, and description thereof will be omitted.

[0094] In the second embodiment, the server 1 further includes a transmitter 11 that transmits the estimation formula updated by the update unit 8 to the external terminal 9. The external terminal 9 includes a battery characteristic acquisition unit 63 that charges and discharges the secondary battery 2 to acquire capacity battery characteristics, and a transmitter 91 that transmits the capacity battery characteristics to the server 1. This allows the server 1 to update the estimation formulas, etc. stored in each external terminal 9 based on the capacity battery characteristics received from multiple external terminals 9, thereby reducing the amount of data communication between the external terminals 9 and the server 1. This prevents a decrease in communication speed, thereby suppressing delays in the deterioration level determination and maintaining high determination accuracy. Note that the second embodiment also achieves the same effects as the first embodiment, except for the effects achieved by the server 1 including the memory unit 5, calculation unit 6, and control unit 7 in the first embodiment.

[0095] Furthermore, in the second embodiment, the external terminal 9 further includes an estimation formula storage unit 52 that stores the estimation formula and the like, a receiving unit 92 that receives update information, an updating unit 8 that updates the estimation formula and the like based on the update information, a deterioration level determination unit 65 that determines the deterioration level of the secondary battery 2, and a display unit 93 that displays the determination result by the deterioration level determination unit 65. This allows the deterioration level of the secondary battery to be determined by the external terminal 9 alone, without communicating with the server 1. Therefore, the deterioration level can be determined even in places where a good communication state cannot be ensured or where a connection to the communication network 200 cannot be made, improving usability.

[0096] The flow of the degradation level determination method by the degradation level determination system 100 of the second embodiment will be described below. First, steps S1 and S2 shown in FIG. 15 are performed similarly to steps S1 and S2 of the first embodiment shown in FIG. 5, and the remaining capacity of each of the secondary batteries 21 to 26 is individually discharged by the charge / discharge control unit 71 using the external terminal 9. Then, steps S3 to S8 shown in FIG. 15 are performed on the external terminal 9 similarly to steps S3 to S8 of the first embodiment shown in FIG. 5. Thereafter, the process proceeds to step S83 shown in FIG. 15, where the determination result is displayed on the display unit 93 of the external terminal 9. Then, the process proceeds to step S9, where the current degradation level determination is completed.

[0097] 15, the process then proceeds to symbol A, where in step S10 the necessity determination unit 60 of the external terminal 9 determines whether or not it is necessary to acquire the capacity battery characteristics. In the second embodiment, as in the first embodiment, the possibility determination unit 62 determines in step S5 that it is necessary to acquire the capacity battery characteristics for a secondary battery for which it is determined that the degradation level cannot be determined, and determines that it is not necessary to acquire the capacity battery characteristics for a secondary battery for which it is determined that the degradation level can be determined. If it is determined in step S10 that there is no secondary battery for which it is determined that it is necessary to acquire the capacity battery characteristics, the process proceeds to No in step S10, and this control flow ends. On the other hand, if it is determined in step S10 that there is a secondary battery for which it is determined that it is necessary to acquire the capacity battery characteristics, the process proceeds to Yes in step S10.

[0098] Then, in step S11 shown in Figure 15, for the secondary battery 2 that is determined to require acquisition of the capacity battery characteristics based on the above instruction information, the charge / discharge control unit 71 of the external terminal 9 charges and discharges it to measure the capacity and obtain the actual measurement value, and then in step S112, the battery characteristics acquisition unit 63 of the external terminal 9 acquires the capacity battery characteristics based on the actual measurement value.

[0099] 15 , the transmission unit 91 of the external terminal 9 transmits the capacity battery characteristics to the server 1, and the reception unit 12 of the server 1 receives the capacity battery characteristics. Then, in step S12, the estimation formula update unit 81 transmits instruction information to the external terminal 9 to instruct the external terminal 9 to update the feasibility determination criteria and the estimation formula stored in the estimation formula storage unit 52 using the capacity battery characteristics as additional training data, and the reception unit 92 of the external terminal 9 receives the instruction information. As a result, the feasibility determination criteria and the estimation formula stored in the estimation formula storage unit 52 of the external terminal 9 are updated, and the updated feasibility determination criteria and the estimation formula will be used for the next and subsequent degradation level determinations. The degradation level determination system 100 and the server 1 of the second embodiment also achieve the same effects as those of the first embodiment.

[0100] In the above-described first modification, the server 1 is further provided with a counter in the configuration of the first embodiment. Similarly, in the ninth modification, the external terminal 9 is further provided with a counter in the configuration of the second embodiment. In the control flow of the ninth modification, as shown in FIG. 16 , if it is determined in step S10 that there is a secondary battery for which it is determined that the capacity battery characteristics need to be acquired, the process proceeds from Yes in step S10 to step S102, as in the second embodiment, where the count number of a counter (not shown) provided in the external terminal 9 is incremented. If it is determined in step S103 that the count number has not reached a predetermined value, the process proceeds to No in step S103, where the external terminal 9 terminates the flow without measuring the capacity. On the other hand, if it is determined in step S103 that the count number has reached the predetermined value, the process proceeds from Yes in step S103 to step S11, and steps S11 and subsequent steps are performed, as in the second embodiment. In variant 9, the estimation formula can be updated at an appropriate frequency to prevent it from becoming too frequent, and the accuracy of determining the degree of deterioration can be maintained high while preventing the computational load on the external terminal 9 from becoming excessively large.

[0101] Furthermore, while in the above-described Modification 2, the server 1 has a time measurement unit instead of the counter of Modification 1, in Modification 10, the external terminal 9 has a time measurement unit instead of the counter of Modification 9. In Modification 10, the time measurement unit starts time measurement when the estimation equation update unit 81 performs an update. Then, in the control flow of Modification 10, as shown in FIG. 17 , the process proceeds from symbol A to step S91, where the time measurement unit of the external terminal 9 determines whether a predetermined time has elapsed since the previous update. If it is determined that the predetermined time has not elapsed, the process proceeds to No in step S91, and the process ends without determining whether or not the capacity battery characteristics need to be acquired. On the other hand, if it is determined in step S91 that the predetermined time has elapsed, the process proceeds from Yes in step S91 to step S10, and steps S10 and thereafter are performed as in the second embodiment. Then, after step S12, the time measurement in the time measurement unit is reset and restarted in step S121.

[0102] According to the tenth modified embodiment, the necessity determining unit 60 determines whether or not it is necessary to acquire the capacity battery characteristics when a predetermined time has elapsed since the previous update performed by the updating unit 8. This makes it possible to prevent the estimation formula from being updated too frequently and to perform updates at an appropriate frequency, thereby preventing the calculation load on the external terminal 9 from becoming excessively large while maintaining high accuracy in determining the degree of deterioration.

[0103] In the second embodiment, the external terminal 9 has all of the components of the calculation unit 6. However, instead, the components of the calculation unit 6 may be arbitrarily distributed between the server 1 and the external terminal 9. For example, in a modified embodiment 11 shown in FIG. 18 , of the components of the calculation unit 6, the necessity determination unit 60, the availability determination unit 62, the capacity estimation unit 64, and the deterioration degree determination unit 65 may be provided in the server 1, and the battery information acquisition unit 61 and the battery characteristics acquisition unit 63 may be provided in the external terminal 9.

[0104] In this eleventh modification, the battery characteristic acquisition unit 63 in the external terminal 9 acquires battery characteristics relating to the transition of the battery state of the secondary battery 2 over a predetermined voltage range or battery characteristic-related values ​​relating to the battery characteristics, and the transmission unit 91 of the external terminal 9 transmits the battery characteristics or the battery characteristic-related values ​​acquired by the battery characteristic acquisition unit 63 to the server 1. This reduces the amount of data communication between the external terminal 9 and the server 1, while also reducing the calculation load on the external terminal 9 and suppressing the specifications required of the external terminal 9, thereby reducing the cost of the external terminal 9. This is therefore advantageous when the deterioration degree determination system 100 is equipped with a large number of external terminals 9.

[0105] (Embodiment 3) In the deterioration level determination system 100 of the above-described first and second embodiments, the battery information acquisition unit 61 acquires the battery characteristics of the secondary battery 2 acquired by the battery characteristics acquisition unit 63 as the battery information. Instead, in embodiment 3, history information of the secondary battery 2 is acquired as the battery information. The history information of the secondary batteries 21 to 26 may include the amount of charge and discharge electricity, battery temperature, state of charge (SOC), number of equalizations, outside temperature, the period of use of the device in which the secondary battery is installed, and maximum, minimum, average, and cumulative values ​​of temperature and other parameters over a predetermined period. The predetermined period may be any period up to the present, or may be the entire period up to the present. The other configurations are the same as those of embodiment 1, and the same reference numerals as those of embodiment 1 are used, and description thereof will be omitted.

[0106] 19 , in the flow of determining the degree of deterioration in the third embodiment, first, step S1 is performed, as in the first embodiment. Then, the process proceeds to step S40, where the battery information acquisition unit 61 of the server 1 attempts to acquire battery information of the secondary batteries 21 to 26 at the external terminal 9 via the communication network 200. In the third embodiment, the battery information acquisition unit 61 attempts to acquire, for example, history information on the amount of electricity charged in each of the secondary batteries 21 to 26 as battery information A, and attempts to acquire, as battery information B, the temperature history of each of the secondary batteries 21 to 26. Note that the types of history information that are attempted to be acquired here are not limited to these.

[0107] 19, the process proceeds to step S41, where it is determined whether or not the battery information A and B has been acquired by the external terminal 9. If the battery information A and B has not been acquired in step S41, the process proceeds to No in step S41, and in step S42, the measurement is deemed to be defective, and the flow ends without determining the degree of deterioration of the secondary battery 2.

[0108] 19, if the external terminal 9 is able to acquire the battery information, the process proceeds to "Yes" in step S41. In step S45, the battery information is transmitted from the transmitter 91 of the external terminal 9 to the server 1, and is received by the receiver 12 of the server 1. Then, in step S5, the possibility determination unit 62 of the server 1 determines whether the deterioration level can be determined, as in the first embodiment. For any of the secondary batteries 21 to 26 whose acquired battery information does not fall within the possibility determination criteria, it is determined that the deterioration level cannot be determined, and, as in the first embodiment, steps S6 and S9 are performed, the process proceeds to symbol A in FIG. 5, and steps S10 to S12 are performed, ending the flow.

[0109] 19, for those secondary batteries 21-26 whose acquired battery information falls within the determination criteria, the determination unit 62 determines that the deterioration level can be determined, and the process proceeds to "Yes" in step S5. Then, in step S20, for those secondary batteries 21-26 for which it has been determined that the deterioration level can be determined, the remaining capacity is individually discharged, similar to step S5 in the first embodiment shown in FIG. 5. Furthermore, if the secondary batteries 21-26 are nickel-metal hydride batteries, the memory effect is also released at the same time.

[0110] 19, as in the first embodiment, the detection value detected by the detector 3 in the external terminal 9 is transmitted to the server 1 by the transmitter 91, and the detection value is received by the receiver 12 of the server 1. Then, in step S3, for those batteries for which it is determined that the degree of deterioration can be determined, the discharge voltage characteristics are acquired as the battery characteristics. Then, as in the first embodiment, steps S7 to S9 are performed, and the flow proceeds to symbol A, where steps S10 to S12 shown in FIG. 5 are performed, and the flow ends.

[0111] In the third embodiment, the battery information acquisition unit 61 acquires, as battery information, history information of the secondary batteries 21 to 26. This allows the possibility of determining the degree of deterioration to be determined based on the history information of the secondary batteries 21 to 26, thereby improving the accuracy of the determination.

[0112] In the deterioration level determination system 100 of the above-described first embodiment, the battery information acquisition unit 61 acquires, as battery information, the battery characteristics of the secondary battery 2 acquired by the battery characteristics acquisition unit 63, while in the deterioration level determination system 100 of the third embodiment, the battery information acquisition unit 61 acquires, as battery information, history information of the secondary battery 2. Instead, the deterioration level determination system 100 of the twelfth modified embodiment is configured to acquire, as battery information, both the battery characteristics acquired by the battery characteristics acquisition unit 63 and history information of the secondary battery 2. The other configurations are the same as those in the first and third embodiments, and the same reference numerals as those in the first and third embodiments are used, and description thereof will be omitted.

[0113] 20, in the flow of determining the degree of deterioration in modified embodiment 12, first, steps S1, S40, and S41 are performed, as in embodiment 3. If the external terminal 9 cannot acquire battery information in step S41, the process proceeds to No in step S41, as in embodiment 3, and in step S42, the measurement is deemed to be insufficient, and the flow is terminated without determining the degree of deterioration of the secondary battery 2.

[0114] On the other hand, if battery information can be acquired in step S41 shown in Fig. 20, the remaining capacity of the secondary battery for which battery information has been acquired is discharged, and if the secondary battery is a nickel-metal hydride battery, the memory effect is also simultaneously removed in step S2 shown in Fig. 20, similar to steps S2 and S3 in the first embodiment shown in Fig. 5. Then, in step S21, the detection value by the detection unit 3 in the external terminal 9 is transmitted to the server 1 by the transmission unit 91, and the detection value is received by the reception unit 12 of the server 1. Thereafter, for those batteries for which it is determined that the degree of deterioration can be determined in step S3, the discharge voltage characteristic is acquired as the battery characteristic, and the process proceeds to step S50.

[0115] 20, the possibility determination unit 62 determines whether the degree of deterioration can be determined based on the battery characteristics and history information of the secondary batteries 21-26 as battery information and the possibility determination criteria. For secondary batteries 21-26 whose acquired battery information does not fall within the possibility determination criteria, it is determined that the degree of deterioration cannot be determined, and, as in the first embodiment, steps S6 and S9 are performed, the process proceeds to symbol A in FIG. 5, steps S10 to S12 are performed, and the flow ends. On the other hand, for secondary batteries 21-26 whose degree of deterioration is determined to be capable of being determined, steps S7 to S9 are performed, the process proceeds to symbol A in FIG. 5, steps S10 to S12 are performed, and the flow ends, as in the first embodiment.

[0116] According to the twelfth modified embodiment, the battery information used to determine whether the degree of deterioration can be determined as described above includes both the battery characteristics and history information of the secondary batteries 21 to 26, so that it is possible to determine whether the degree of deterioration can be determined with even greater accuracy. Note that the twelfth modified embodiment also achieves the same effects as the first and second embodiments.

[0117] (Embodiment 4) The deterioration level determination system 100 of this embodiment 4 has the same configuration as that of the above-described embodiment 3. In this embodiment 4, a first feasibility determination criterion D1 and a second feasibility determination criterion D2 are stored in the estimation formula storage unit 52. In this embodiment 4, the first feasibility determination criterion D1 is stored as the inter-data distance D1, and the second feasibility determination criterion D2 is stored as the inter-data distance D2, with the relationship between the two being D1<D2.

[0118] In the fourth embodiment, the correspondence storage unit 51 stores a first correspondence and a second correspondence. The first correspondence is a correspondence suitable for determining the degree of deterioration of a secondary battery determined to be capable of being determined based on the first feasibility determination criterion D1. The second correspondence is a correspondence suitable for determining the degree of deterioration of a secondary battery determined to be capable of being determined based on the second feasibility determination criterion D2. The correspondence can be created in the same manner as in the first embodiment.

[0119] Next, the flow of the degradation level determination method by the degradation level determination system 100 of the fourth embodiment will be described below with reference to FIG. 21 . Note that in the fourth embodiment, components equivalent to those in the third embodiment shown in FIG. 19 are assigned the same reference numerals, and their description will be omitted. In the flow of the fourth embodiment, instead of the third embodiment shown in FIG. 19 , as shown in FIG. 21 , after the server 1 receives battery information in step S44, the possibility determination unit 62 determines in step S51 whether it is possible to determine the degradation level of the secondary battery for which battery information has been acquired based on the first possibility determination criterion D1. Then, for those secondary batteries for which it is determined in step S51 that it is possible to determine the degradation level, the process proceeds to Yes in step S51, and steps S20, S21, and S3 shown in FIG. 21 are performed in the same manner as steps S20 to S3 of the third embodiment shown in FIG. 19 .

[0120] 21, the capacity estimation unit 64 estimates the total capacity, i.e., the full charge capacity or the full discharge capacity, of the secondary batteries 21 to 26 for which it has been determined in step S51 that the degree of deterioration can be determined, from the battery characteristics acquired by the battery characteristics acquisition unit 63, based on the first correspondence between the battery characteristics and the total capacity based on the prediction model stored in the correspondence storage unit 51. Then, as in the third embodiment, the degree of deterioration is determined in step S8, step S9 is performed, and the process proceeds to symbol A in FIG. 5, where steps S10 to S12 are performed to end the flow.

[0121] 21, for those of the secondary batteries 21 to 26 for which it is not possible to determine the degree of deterioration based on the first determination criterion D1, the process proceeds to No in step S51. Then, in step S52, for those of the secondary batteries 21 to 26 for which it is determined in step S51 that it is not possible to determine the degree of deterioration, the determination unit 62 determines whether it is possible to determine the degree of deterioration based on the second determination criterion D2. Then, if it is determined in step S52 that it is possible to determine the degree of deterioration, the process proceeds to Yes in step S52, and steps S22, S23, and S24 shown in FIG. 21 are performed in the same manner as steps S20 to S3 in the third embodiment shown in FIG.

[0122] 21, the capacity estimation unit 64 estimates the total capacity, i.e., the full charge capacity or the full discharge capacity, for each of the secondary batteries 21 to 26 for which it is determined in step S52 that the degree of deterioration can be determined, based on the second correspondence between the battery characteristics and the total capacity, which is based on the prediction model stored in the correspondence storage unit 51, from the battery characteristics acquired by the battery characteristics acquisition unit 63. Then, as in the third embodiment, the degree of deterioration is determined in step S8, and the process proceeds to step S9, where the current determination of the degree of deterioration is terminated. On the other hand, for each of the secondary batteries 21 to 26 for which it is determined in step S52 that the degree of deterioration cannot be determined, the process proceeds to No in step S52, and then to steps S6 and S9, where the current determination of the degree of deterioration is terminated, as in the first embodiment. After step S9, the process proceeds to symbol A in FIG. 5, where steps S10 to S12 are performed, where the process ends.

[0123] The deterioration level determination system 100 of the fourth embodiment has a first possibility determination criterion D1 and a second possibility determination criterion D2 as multiple possibility determination criteria, and has a first correspondence relationship and a second correspondence relationship appropriate for items determined to be capable of being determined as deterioration levels by the respective possibility determination criteria as multiple correspondence relationships. This provides high consistency between the possibility determination criteria for the deterioration level and the deterioration level determination criteria, enabling the deterioration level to be determined with higher accuracy. Note that the present embodiment also provides the same effects as the first embodiment.

[0124] (Embodiment 5) In a deterioration level determination system 100 according to embodiment 5, as shown in FIG. 22 , the calculation unit 6 further includes a vehicle information acquisition unit 66. Examples of vehicle information include the vehicle model of the vehicle 900, the product number of the battery pack or secondary battery module, the position of the module in the battery pack, the year of manufacture, service life, and mileage of the vehicle 900, and the location of the dealer of the vehicle 900. The estimation formula storage unit 52 stores vehicle information criteria as vehicle information criteria for determining whether or not the deterioration level can be determined. In embodiment 5, a plurality of specific vehicle models are stored as vehicle information. The correspondence storage unit 51 stores correspondence relationships corresponding to the specific vehicle models. The other components are the same as those in embodiment 1 shown in FIG. 1 and embodiment 3 (not shown), and the same reference numerals are used, and description thereof will be omitted.

[0125] Next, the flow of the deterioration level determination method by the deterioration level determination system 100 of the fifth embodiment will be described below with reference to FIG. 23 . In the fifth embodiment, components equivalent to those in the third embodiment shown in FIG. 19 are assigned the same reference numerals, and their description will be omitted. In the flow of the fifth embodiment, instead of step S40 of the third embodiment shown in FIG. 19 , the flow proceeds to step S46 after step S1, as shown in FIG. 23 , in which the vehicle information acquisition unit 66 attempts to acquire vehicle information of the vehicle 900 in which the battery pack 20 is mounted at the external terminal 9 via the communication network 200. Then, in step S47, the transmission unit 91 of the external terminal 9 transmits the vehicle information to the server 1, and the reception unit 12 of the server 1 receives the vehicle information. Note that the vehicle information is not limited to, but is the model of the vehicle 900 in the fifth embodiment.

[0126] 23, the feasibility determination unit 62 determines whether the vehicle information acquired by the vehicle information acquisition unit 66 matches the vehicle information standard. In the fifth embodiment, it is determined whether the vehicle model acquired by the vehicle information acquisition unit 66 matches a specific vehicle model stored in the estimation formula storage unit 52. If it is determined in step S48 that the vehicle model does not match a specific vehicle model, the process proceeds to No in step S48, and the flow ends without determining the degree of deterioration in step S42, as in the third embodiment.

[0127] On the other hand, if it is determined in step S48 of FIG. 23 that the acquired vehicle information meets the vehicle information standard, the process proceeds to Yes in step S48. Then, steps S40 and onward are executed until the end of the control flow, as in the third embodiment. However, in step S73, instead of step S7 in the third embodiment, the capacity estimation unit 64 estimates the total capacity in accordance with the vehicle information. That is, the estimation formula used to estimate the total capacity in the capacity estimation unit 64 is changed in accordance with the vehicle information.

[0128] According to the deterioration degree determination system 100 of the fifth embodiment, the capacity estimation unit 64 can determine the deterioration degree according to the vehicle model by using an estimation formula that estimates the total capacity corresponding to the vehicle model as vehicle information, thereby further improving the estimation accuracy. Note that the deterioration degree determination system 100 of the fifth embodiment can also achieve the same effects as those of the first embodiment.

[0129] Sixth Embodiment In a deterioration level determination system 100 according to the sixth embodiment, in addition to the configuration of the first embodiment shown in Fig. 1, the calculation unit 6 includes an impedance characteristics acquisition unit 67 as shown in Fig. 24. The impedance characteristics acquisition unit 67 has a configuration for performing complex impedance measurement, and is configured to be able to measure the impedances of the secondary batteries 21 to 26. The other configurations are the same as those of the first embodiment, and the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0130] In the sixth embodiment, the battery characteristic acquisition unit 63 acquires the discharge voltage characteristic in the predetermined voltage section Vs shown in Fig. 3, as in the first embodiment. Then, the impedance characteristic acquisition unit 67 acquires the discharge voltage characteristic in the predetermined voltage section Vs shown in Fig. 3. Ｐ１ , T Ｐ２ Complex impedance measurement is performed at this point to obtain the impedance at a predetermined frequency, and values ​​on the real axis and imaginary axis are calculated on the complex plane.

[0131] Here, the impedance characteristics can be represented by the real and imaginary axis values ​​of the impedance at a predetermined frequency f1, or the absolute value calculated from the real and imaginary axis values. In addition, the argument calculated from the real and imaginary axis values ​​at a predetermined frequency f1 can also be used. Furthermore, the difference between the real and imaginary axis values ​​at a predetermined frequency f1 and a predetermined frequency f2, the difference between the real and imaginary axis values, and the difference between the absolute values ​​and the argument calculated from the difference between the real and imaginary axis values ​​can also be used.

[0132] The correspondence between the impedance characteristics and the total capacity is stored in advance in the correspondence storage unit 51. The correspondence can be created by machine learning using the measurement secondary battery 2, created based on actual measurement values ​​obtained by performing an accelerated degradation test using the measurement secondary battery, or created by a calculation formula that logically derives the correspondence between the impedance characteristics and the total capacity at a predetermined voltage using a model of the secondary battery.

[0133] In the sixth embodiment, similarly to the first embodiment, after the possibility determination unit 62 determines whether the degree of deterioration can be determined, a capacity estimation unit 64 shown in Fig. 24 estimates the total capacity of the secondary battery 2 based on the discharge voltage characteristics acquired by the battery characteristics acquisition unit 63 and the impedance characteristics acquired by the impedance characteristics acquisition unit 67. As in the first embodiment, the deterioration degree determination unit 65 determines the degree of deterioration of the secondary battery 2 based on the estimation result of the capacity estimation unit 64. According to the sixth embodiment, the total capacity is estimated based on the discharge voltage characteristics and the impedance characteristics, and therefore the determination accuracy can be further improved.

[0134] In the sixth embodiment, the timing at which the impedance characteristic acquisition unit 67 performs the complex impedance measurement is set to the discharge end time T Ｐ１ , T Ｐ２ However, the present invention is not limited to this, and other timings may be used. For example, when the battery characteristics acquisition unit 63 acquires the charging voltage characteristics as in the fourth modified embodiment, the charging end time T Ｑ１ , T Ｑ２The impedance characteristic acquisition unit 67 may perform complex impedance measurement. The capacitance estimation unit 64 may use an impedance characteristic relation value calculated based on the impedance characteristics instead of the impedance characteristics. For example, the difference between the impedance characteristics acquired by the impedance characteristic acquisition unit 67 may be used as the impedance characteristic relation value.

[0135] The deterioration level determination system 100 of the sixth embodiment can provide a battery pack including a plurality of secondary batteries with usage histories, in which the difference in the degree of deterioration of the plurality of secondary batteries determined based on total capacities estimated using battery characteristics and impedance characteristics related to impedance when the secondary batteries are discharged or charged is within a predetermined range. In such a battery pack, the variation in the degree of deterioration of the secondary batteries included in the battery pack is reduced, thereby enabling the battery pack to be rebuilt with a longer life and improved quality.

[0136] In the sixth embodiment, the deterioration level determination unit 65 may determine the deterioration levels of the secondary batteries 21 to 26 based on the battery characteristics and impedance characteristics acquired by the battery characteristics acquisition unit 63, without estimating the total capacity. Alternatively, the battery characteristics acquisition unit 63 may acquire absolute values ​​of the acquired values ​​as battery characteristics, and the deterioration level determination unit 65 may determine the deterioration levels based on the absolute values. Alternatively, the deterioration level determination unit 65 may determine the deterioration levels of the secondary batteries 21 to 26 based on differences in the battery characteristics acquired by the battery characteristics acquisition unit 63. Alternatively, the secondary batteries 21 to 26 may be classified into classes so that the deterioration levels of the secondary batteries 21 to 26 and the differences in the deterioration levels fall within a predetermined range, and the assembled battery 20 may be assembled.

[0137] Seventh Embodiment In the seventh embodiment, in addition to the configuration of the first embodiment shown in Fig. 1, an initial voltage acquisition unit 68 is provided as shown in Fig. 25. The initial voltage acquisition unit 68 acquires a voltage at the start of discharge T ０The initial voltages VI1 and VI2, which are the open circuit voltages of the secondary battery 2 at the time of the measurement, are acquired. The correspondence relationship storage unit 51 stores in advance the correspondence relationships between the initial voltage values, the battery characteristics, and the total capacity. The correspondence relationships can be created in the same way as in the first embodiment. The other configurations are the same as in the first embodiment, and the same components as in the first embodiment are denoted by the same reference numerals and their description will be omitted.

[0138] According to the deterioration level determination system 100 of the seventh embodiment, the deterioration level of the secondary battery 2 is determined taking into consideration not only the battery characteristics but also the initial voltage, thereby further improving the determination accuracy with a simple configuration. Note that, instead of the initial voltage, an initial voltage relationship value calculated based on the initial voltage may be used. For example, the initial voltage relationship value may be the absolute value of the initial voltage or the difference in the initial voltage acquired by the initial voltage acquisition unit 68.

[0139] The deterioration level determination system 100 of the seventh embodiment can provide an assembled battery 20 including secondary batteries 21 to 26 with usage histories, in which the difference in the degree of deterioration of the plurality of secondary batteries 21 to 26 is within a predetermined range, determined based on the total capacity estimated using the battery characteristics and the initial voltage, which is the open-circuit voltage of the secondary batteries 21 to 26 when acquisition of the battery characteristics begins. In such an assembled battery 20, the variation in the degree of deterioration of the secondary batteries 21 to 26 included in the assembled battery 20 is reduced, thereby enabling the assembled battery 20 to be rebuilt with a longer life and improved quality.

[0140] In the seventh embodiment, similar to the modified example of the first embodiment, the deterioration level determination unit 65 may determine the deterioration levels of the secondary batteries 21 to 26 based on the battery characteristics and initial voltages acquired by the battery characteristics acquisition unit 63, without estimating the total capacity. Alternatively, the battery characteristics acquisition unit 63 may acquire absolute values ​​of the acquired values ​​as battery characteristics, and the deterioration level determination unit 65 may determine the deterioration levels based on the absolute values. Alternatively, the deterioration level determination unit 65 may determine the deterioration levels of the secondary batteries 21 to 26 based on differences in the battery characteristics acquired by the battery characteristics acquisition unit 63. The secondary batteries 21 to 26 may be classified into classes so that the deterioration levels of the secondary batteries 21 to 26 and the differences in the deterioration levels fall within a predetermined range, and the assembled battery 20 may be assembled.

[0141] In another variation 13, as shown in FIG. 27 , the calculation unit 6 may include an internal resistance acquisition unit 69 that acquires the internal resistance of the secondary batteries 21-26, and the correspondence between the internal resistance, battery characteristics, and total capacity may be stored in advance in the correspondence relationship storage unit 51. The internal resistance acquisition unit 69 can acquire the internal resistance by calculating the measured voltage (i.e., the voltage value detected by the voltage value detection unit 31), the open-circuit voltage of the secondary batteries 21-26, and the current flowing through the secondary batteries 21-26. The open-circuit voltage of the secondary batteries 21-26 can be estimated and acquired over time using a map showing the correspondence between the remaining discharge capacity and the initial voltage of the secondary batteries 21-26. The deterioration level determination system 100 of this variation 13 determines the deterioration level of the secondary batteries 21-26 by taking into account the internal resistance in addition to the battery characteristics, thereby further improving the determination accuracy with a simple configuration.

[0142] (Embodiment 8) A deterioration level determination system 100 of Embodiment 8 includes a temperature detection unit 33 as shown in FIG. 28 in addition to the configuration of Embodiment 1 shown in FIG. 1 . In the above-described Embodiment 1, the battery characteristics acquisition unit 63 is configured to acquire, as the battery characteristics, discharge voltage characteristics based on voltage transitions of the secondary battery 2 in a predetermined voltage interval Vs. However, in Embodiment 8, instead, the battery characteristics acquisition unit 63 acquires, as the battery characteristics, temperature characteristics based on temperature transitions of the secondary battery 2 in predetermined voltage intervals VsA and VsB. The other configurations are the same as those of Embodiment 1, and the same components as those of Embodiment 1 are assigned the same reference numerals and their description will be omitted. Note that the voltage interval VsA is a section in which the discharge voltage characteristics differ significantly depending on the deterioration level of the secondary battery 2, and the voltage interval VsB is a section in which the charge voltage characteristics differ significantly depending on the deterioration level of the secondary battery 2.

[0143] 29(a) and 29(b), in the eighth embodiment, the temperature of the secondary battery 2 during charging and discharging is acquired by the temperature detection unit 33. In the eighth embodiment, the first secondary battery 21 removed from the assembled battery 20 and the seventh secondary battery 27 removed from another assembled battery are used as secondary batteries 2 determined to be capable of being determined for their degree of deterioration.

[0144] The temperature transition of the secondary battery 2 during charging and discharging may behave differently depending on the measurement environment and soak state of the secondary battery 2 when the assembled battery is different. In the eighth embodiment, as shown in FIG. 29( b), the temperature transitions of the first secondary battery 21 and the seventh secondary battery 27 are within the measured room temperature setting range Tn, but they behave slightly differently from each other. In the eighth embodiment, after the possibility determination unit 62 determines that the deterioration level can be determined, the battery characteristics acquisition unit 63 acquires the temperature characteristics during discharging and the temperature characteristics during charging based on the battery temperatures detected by the temperature detection unit 33 in both the predetermined voltage section VsA during discharging and the predetermined voltage section VsB during charging after discharging. The capacity estimation unit 64 then estimates the total capacity of each secondary battery 21, 27 based on both temperature characteristics, and the deterioration level determination unit 65 determines the deterioration level.

[0145] The temperature characteristics acquired by the battery characteristics acquisition unit 63 can be the differential value of the temperature change at specified voltages VA and VB in the specified voltage ranges VsA and VsB, the ratio of the temperature change between two points in the specified voltage ranges VsA and VsB, or the ratio of the temperature change of the secondary battery 2 to the change in capacity of the secondary battery 2 in the voltage ranges VsA and VsB, as when calculating the discharge voltage characteristics in embodiment 1 and the charge voltage characteristics in embodiment 4.

[0146] In the present embodiment 8, the same effects as those in the embodiment 1 can be achieved. Note that in the present embodiment 8, the temperature characteristics are acquired in both discharging and charging, but this is not limiting, and the temperature characteristics may be acquired in only one of discharging and charging.

[0147] The deterioration level determination system 100 of the eighth embodiment can provide a battery pack including secondary batteries with a usage history, in which the difference in the degree of deterioration of the multiple secondary batteries determined based on total capacities estimated using battery characteristics including temperature characteristics based on temperature transitions of the secondary batteries in predetermined voltage intervals VsA and VsB is within a predetermined range. In such a battery pack, the variation in the degree of deterioration of the secondary batteries included in the battery pack is reduced, thereby improving the quality of the battery pack as a rebuilt product.

[0148] In the eighth embodiment, the deterioration degree determination unit 65 may also determine the deterioration degree of the secondary batteries 21 to 26 based on the temperature characteristics acquired by the battery characteristics acquisition unit 63, without estimating the total capacity. Alternatively, the battery characteristics acquisition unit 63 may acquire the absolute value of the acquired value as the temperature characteristic, and the deterioration degree determination unit 65 may determine the deterioration degree based on the absolute value. Alternatively, the deterioration degree determination unit 65 may determine the deterioration degree of the secondary batteries 21 to 26 based on the difference in the temperature characteristics acquired by the battery characteristics acquisition unit 63. Alternatively, the secondary batteries 21 to 26 may be classified into classes so that the deterioration degrees of the secondary batteries 21 to 26 and the difference in the deterioration degrees fall within a predetermined range, and the assembled battery 20 may be assembled.

[0149] In the eighth embodiment, as shown in FIG. 29( a), the temperature characteristics during charging are acquired when the charge target voltage VQ is within the normal operating range Vn and the predetermined voltage section VsA is within the normal operating range Vn. However, as shown in FIG. 30( a), as a modified embodiment 14, the temperature characteristics during charging may be acquired when the charge target voltage VQ exceeds the normal operating range Vn and the predetermined voltage section VsB is within the normal operating range Vn. In this case, as shown in FIG. 30( b), the temperature of the secondary batteries 21, 27 tends to rise, making it easier for the temperature transition to reflect the degree of deterioration. As a result, the accuracy of the determination can be improved. In the modified embodiment 14, the secondary batteries 21, 27 are charged to the charge target voltage VQ and then discharged to return the voltage of the secondary batteries 21, 27 to the normal operating range Vn.

[0150] In addition, in Modification 14, the secondary battery 2 is discharged, then charged, and then discharged again. However, instead of this, as shown in Modification 15 in Figures 31(a) and 31(b), the secondary battery 2 may be charged first and then discharged, rather than being discharged first. In this case, the battery characteristics acquisition unit 63 may acquire the temperature characteristics during charging during charging, and then the temperature characteristics during discharging during discharging. This also achieves the same effects as in Embodiment 1.

[0151] (Embodiment 9) In the above-described embodiment 1, the capacity estimation unit 64 as an estimation unit estimates the total capacity of the secondary battery 2 based on the battery characteristics acquired by the battery characteristics acquisition unit 63. However, this is not limited thereto. The capacity estimation unit 64 may estimate at least one of the positive electrode capacity, the negative electrode capacity, the deviation amount of the relative relationship between the negative electrode SOC and the positive electrode SOC, the total capacity variation among the multiple cells constituting the secondary batteries 21 to 26, and the battery resistance, positive electrode resistance, and negative electrode resistance of the secondary batteries 21 to 26. In embodiment 9, the capacity estimation unit 64 estimates the positive electrode capacity Qc of each of the secondary batteries 21 to 26. Furthermore, the correspondence storage unit 51 stores a correspondence relationship between the battery characteristics and the positive electrode capacity Qc. The form and creation method of the correspondence relationship are not particularly limited, and as in embodiment 1, it may be in the form of, for example, a calculation formula, a map, a graph, a table, or the like. The correspondence relationship can be created by machine learning using the measurement secondary battery 2, based on actual measurements obtained by performing an accelerated degradation test using the measurement secondary battery 2, or by a calculation formula that logically derives the correspondence relationship between the battery characteristics and the total capacity in a predetermined voltage range using a model of the secondary battery 2. In the ninth embodiment, the correspondence relationship storage unit 51 stores the correspondence relationship between the battery characteristics and the positive electrode capacity Qc based on, for example, the prediction models shown in FIGS. 32( a) to 32(c). The other configurations are the same as those in the first embodiment, and the same reference numerals as those in the first embodiment are used, and description thereof will be omitted.

[0152] Next, a method for determining the degree of deterioration by the deterioration degree determination system 100 of the ninth embodiment will be described below. Note that steps similar to those in the first embodiment shown in FIG. 5 are designated by the same reference numerals, and their description may be omitted. First, in the ninth embodiment, steps S1 to S5 shown in FIG. 33 are performed, as in the first embodiment shown in FIG. 5. As a result, as shown in FIG. 34(a), the battery characteristics acquisition unit 63 acquires a discharge curve as the battery characteristics of each of the secondary batteries 21 to 26 in a predetermined voltage range Vs. Note that the predetermined voltage range can be a range corresponding to a specific SOC range.

[0153] Next, in step S74 shown in FIG. 33 , the capacity estimation unit 64 estimates the positive electrode capacities Qc of the secondary batteries 21 to 26 from the discharge curves acquired by the battery characteristics acquisition unit 63 based on the correspondence between the battery characteristics and the positive electrode capacities Qc, based on the prediction model stored in the correspondence storage unit 51. Thereafter, in step S8 shown in FIG. 33 , the deterioration level determination unit 65 determines the deterioration levels of the secondary batteries 21 to 26 based on the positive electrode capacities Qc estimated by the capacity estimation unit 64. The other steps are performed in the same manner as in the first embodiment shown in FIG. 5 . However, while the first embodiment shown in FIG. 5 acquires an actual capacity measurement value in step S11 and transmits the actual measurement value from the external terminal 9 to the server 1 in step S111, the ninth embodiment instead acquires an actual positive electrode capacity Qc in step S11 shown in FIG. 33 and transmits the actual measurement value from the external terminal 9 to the server 1 in step S111. The ninth embodiment also achieves the same effects as the first embodiment.

[0154] In the ninth embodiment, the discharge curve shown in Fig. 34(a) is acquired by the battery characteristics acquisition unit 63, but instead, the charge curve shown in Fig. 34(b) may be acquired. In this case, the same effects as those of the first embodiment can be achieved.

[0155] (Embodiment 10) In the above-described embodiment 9, the capacity estimation unit 64 estimates the positive electrode capacity Qc. However, in this embodiment 10, the capacity estimation unit 64 instead estimates the negative electrode capacity QA. That is, in the embodiment 10, as shown in FIG. 35 , in step S75, the capacity estimation unit 64 estimates the negative electrode capacity QA of the secondary batteries 21 to 26 based on the correspondence between the battery characteristics and the negative electrode capacity QA, in accordance with the prediction model shown in FIGS. 32(a) to 32(c). Thereafter, in step S8 shown in FIG. 35 , the deterioration level determination unit 65 determines the deterioration level of the secondary batteries 21 to 26 based on the negative electrode capacity QA estimated by the capacity estimation unit 64. The other steps are the same as in embodiment 1, except that in step S11, an actual measurement value of the negative electrode capacity QA is acquired, and in step S111, the actual measurement value is transmitted from the external terminal 9 to the server 1. The embodiment 10 also achieves the same effects as embodiment 1.

[0156] Eleventh Embodiment In this eleventh embodiment, a capacity estimation unit 64 estimates the amount of deviation in the relative relationship between the negative electrode SOC and the positive electrode SOC of each of the secondary batteries 21 to 26. Furthermore, a correspondence relationship between battery characteristics and the amount of deviation in the relative relationship between the negative electrode SOC and the positive electrode SOC is stored in a correspondence relationship storage unit 51. The form and creation method of this correspondence relationship are not particularly limited and can be the same as in the first embodiment.

[0157] For example, if the secondary batteries 21 to 26 are nickel-metal hydride batteries, when hydrogen escapes from the reaction system in the battery case, the relative relationship between the negative electrode SOC and the positive electrode SOC shifts, causing the negative electrode OCV curve to shift to the right in the diagram, as shown in Fig. 36. For example, if the secondary batteries 21 to 26 are lithium-ion batteries, as shown in Fig. 36, the lithium in the electrolyte is consumed in the formation of an SEI (Solid Electrolyte Interface) film, causing the relative relationship between the negative electrode SOC and the positive electrode SOC shifts, causing the negative electrode OCV curve to shift to the right in the diagram.

[0158] In the eleventh embodiment, the correspondence between the deviation amount Qx of the relative relationship between the negative electrode SOC and the positive electrode SOC and the battery characteristics is stored in the correspondence storage unit 51 based on the prediction model shown in Fig. 36. The other configurations are the same as those in the first embodiment, and the same reference numerals as in the first embodiment are used, and the description thereof will be omitted.

[0159] The degradation level determination method by the degradation level determination system 100 of the eleventh embodiment is performed in the same manner as in the ninth embodiment, except that, as shown in FIG. 37 , in step S3, the battery characteristics acquisition unit 63 acquires a discharge curve in a predetermined voltage range Vs corresponding to a low SOC range of the battery as the battery characteristics. Then, as in the first embodiment shown in FIG. 5 , steps S4 to S5 shown in FIG. 37 are performed. Then, in step S76, the capacity estimation unit 64 estimates the deviation amount Qx of the secondary batteries 21 to 26 based on the correspondence between the battery characteristics calculated from the discharge curve and the deviation amount Qx of the relative relationship between the negative electrode SOC and the positive electrode SOC stored in the correspondence storage unit 51. Then, in step S8 shown in FIG. 37 , the degradation level determination unit 65 determines the degradation level of the secondary batteries 21 to 26 based on the deviation amount Qx estimated by the capacity estimation unit 64. The other steps are the same as in the first embodiment, but in step S11, an actual measurement value of the deviation amount Qx is acquired, and in step S111, the actual measurement value is transmitted from the external terminal 9 to the server 1. The same effects as in the first embodiment are achieved in the eleventh embodiment. Note that, although the battery characteristics are acquired from the low SOC range of the battery in the eleventh embodiment, they may be acquired from the high SOC range instead. Furthermore, although a discharge curve is acquired as the battery characteristics in the eleventh embodiment, a charge curve may be acquired.

[0160] In this embodiment, the correspondence storage unit 51 stores the correspondence between the battery characteristics and the amount of change in discharge capacity on the charge / discharge curve for each of the secondary batteries 21 to 26, the capacity estimation unit 64 estimates the amount of change in discharge capacity on the charge / discharge curve in a predetermined voltage range Vs, and the deterioration level determination unit 65 detects whether the amount of self-discharge of the cell is increasing based on the estimation result as the degree of deterioration. In this embodiment, the other configurations are the same as in the first embodiment, and the same reference numerals as in the first embodiment are used, and their description will be omitted.

[0161] In this twelfth embodiment, each of the secondary batteries 21 to 26 has six cells. For example, the discharge curve shown in FIG. 38( a) is stored in the correspondence relationship storage unit 51 as a discharge curve representing an initial state, and the discharge curve shown in FIG. 38( b) is stored in the correspondence relationship storage unit 51 as a discharge curve representing a state in which one of the cells has a large self-discharge amount. When the capacity estimation unit 64 estimates the discharge curve shown in FIG. 38( a) based on the battery characteristics in a predetermined voltage range Vs, the deterioration level determination unit 65 determines that no cell has a large self-discharge amount. On the other hand, when the capacity estimation unit 64 estimates the discharge curve shown in FIG. 38( b) based on the battery characteristics in a predetermined voltage range Vs, the deterioration level determination unit 65 determines that one cell has a large self-discharge amount. Note that when the discharge curve shown in FIG. 38( b) is estimated, the lower limit of use can be set to a second lower limit of use Vmin2, which is higher than the first lower limit of use Vmin1 when no cell in the secondary battery has a large self-discharge amount. This prevents each cell from being excessively discharged.

[0162] (Embodiment 13) In this embodiment 13, each of the secondary batteries 21 to 26 includes six cells. The correspondence storage unit 51 stores correspondences between the total capacity variation between the cells in each of the secondary batteries 21 to 26 and the battery characteristics. The total capacity variation between the cells indicates the degree of variation in the total capacity of each of the multiple cells included in one of the secondary batteries 21 to 26. In this embodiment 13, the difference Qmax-min, calculated by subtracting the minimum Qmin from the maximum Qmax of the total capacities of the multiple cells, is used as the total capacity variation between the cells, as shown in FIG. 39 . Other configurations are the same as those in the first embodiment, and the same reference numerals as in the first embodiment are used, and their description will be omitted.

[0163] In the thirteenth embodiment, the capacity estimation unit 64 estimates the difference Qmax-min from the correspondence stored in the correspondence storage unit 51, based on the battery characteristics acquired by the battery characteristics acquisition unit 63. Then, the deterioration degree determination unit 65 detects the presence or absence of specific capacity deterioration of the cell based on the estimated difference Qmax-min. For example, if it is determined that the estimated difference Qmax-min is equal to or greater than a predetermined value, it is determined that specific capacity deterioration has occurred in one of the cells of the secondary batteries 21 to 26.

[0164] In addition, when the external terminal 9 is equipped with the correspondence relationship storage unit 51, capacity estimation unit 64, etc. as in embodiment 2, by performing steps S74, S75, or S76 in embodiments 9 to 13 instead of step S7 in Figure 15, the same effects as those of embodiments 9 to 13 can be obtained.

[0165] Fourteenth Embodiment In the fourteenth embodiment, as shown in FIG. 40 , the estimation unit includes a resistance estimation unit 641 instead of the capacity estimation unit 64 of the first embodiment. The resistance estimation unit 641 estimates the internal resistance of the secondary batteries 21 to 26 based on the battery characteristics of the secondary batteries 21 to 26. The correspondence storage unit 51 stores the correspondence between the internal resistance and the battery characteristics of each of the secondary batteries 21 to 26. The battery characteristics acquisition unit 63 can acquire the battery characteristics by performing pulse charging and discharging while the secondary batteries 21 to 26 are connected to one another in a stack state. The voltage interval for acquiring the battery characteristics can be a predetermined voltage interval corresponding to a specific SOC range.

[0166] Furthermore, if the temperatures and SOCs of the secondary batteries 21 to 26 are different, the temperature and the voltage change during charging and discharging or the voltage change during voltage relaxation after charging and discharging can be acquired as battery characteristics to estimate the resistance value when the temperature and SOC are the same. In this case, the correspondence relationship storage unit 51 stores the correspondence relationship between the internal resistance, temperature, and battery characteristics of each of the secondary batteries 21 to 26. Note that the secondary batteries 21 to 26 may be charged and discharged individually to acquire the battery characteristics. In this case, there is no need to set the temperature and SOC to the same conditions, and the determination time can be shortened.

[0167] Next, a method for determining the degree of deterioration by the deterioration degree determination system 100 of the fourteenth embodiment will be described below. First, in the fourteenth embodiment, steps S1 to S5 shown in FIG. 41 are performed, similarly to the first embodiment shown in FIG. 5. Next, in step S77 shown in FIG. 41, the resistance estimation unit 641 acquires the internal resistances of the secondary batteries 21 to 26 from the battery characteristics acquired by the battery characteristics acquisition unit 63, based on the correspondence between the internal resistances of the secondary batteries 21 to 26 and the battery characteristics stored in the correspondence storage unit 51. Thereafter, in step S8 shown in FIG. 41, the deterioration degree determination unit 65 determines the degree of deterioration of the secondary batteries 21 to 26 based on the internal resistances estimated by the resistance estimation unit 641.

[0168] Furthermore, in the first embodiment, in step S10 shown in FIG. 5, the necessity determination unit 60 determines whether or not it is necessary to acquire the capacity battery characteristic as a battery characteristic. However, in the fourteenth embodiment, instead, in step S100 shown in FIG. 41, the necessity determination unit 60 determines whether or not it is necessary to acquire the resistance battery characteristic as a battery characteristic. The resistance battery characteristic refers to the battery characteristic of the secondary batteries 21 to 26 based on the resistance value in a predetermined state. The other steps are the same as in the first embodiment, but in step S11, an actual measurement value of the internal resistance is acquired, and in step S111, the actual measurement value is transmitted from the external terminal 9 to the server 1. The fourteenth embodiment also achieves the same effects as the first embodiment.

[0169] Fifteenth Embodiment In a deterioration level determination system 100 according to a fifteenth embodiment, the resistance estimation unit 641 estimates the negative electrode resistance of the secondary batteries 21 to 26, and the deterioration level determination unit 65 determines the deterioration levels of the secondary batteries 21 to 26.

[0170] The resistance values ​​of the positive and negative electrodes and other battery elements of the secondary batteries 21-26 can be calculated from the frequency characteristics of the voltage curves of the secondary batteries 21-26. In nickel-metal hydride batteries and lithium-ion batteries, the negative electrode resistance is significantly reflected in the high-frequency range of the voltage curve, and the positive electrode resistance is significantly reflected in the low-frequency range. In the fifteenth embodiment, nickel-metal hydride batteries are used as the secondary batteries 21-26, and the battery characteristics acquisition unit 63 acquires, as the battery characteristics, voltage curves in a predetermined voltage range in the high-frequency range. The correspondence storage unit 51 pre-stores, as battery characteristics, the correspondence between the voltage curve in the high-frequency range and the negative electrode resistance. The other components are the same as those in the fourteenth embodiment, and the same reference numerals are used, and their description will be omitted.

[0171] The dominant resistance element in the internal resistance, which correlates with the degree of deterioration of the secondary batteries 21 to 26, differs depending on the deterioration mode. First, the internal resistance of a secondary battery is determined by the relationship between three resistance components: electronic resistance, reaction resistance, and internal mass transfer resistance. A secondary battery can be considered a series equivalent circuit of these three resistance components. Generally, electronic resistance is a resistance component that occurs primarily in the time domain immediately after a constant current is applied to the battery. Reaction resistance is a resistance component that occurs primarily in the time domain after the time domain in which electronic resistance occurs. Internal mass transfer resistance occurs when a constant current is applied for a long period of time, and is a resistance component that occurs primarily in the time domain after the time domain in which reaction resistance occurs. The negative electrode reaction resistance-dominated region is the time domain in which the proportion of the negative electrode reaction resistance during the discharge period is the largest among the three resistance components. In this negative electrode reaction resistance-dominated region, the negative electrode reaction resistance dominantly determines the internal resistance of the secondary battery 2. In the fifteenth embodiment, the deterioration level determining unit 65 determines the deterioration level of the secondary batteries 21 to 26 based on the negative electrode resistance estimated by the resistance estimating unit 641 in the negative electrode reaction resistance dominated region.

[0172] In the degradation level determination method by the degradation level determination system 100 of the present embodiment 15, steps S1 to S5 shown in FIG. 41 are performed, similarly to the case of the embodiment 14. Then, in step S77, the resistance estimation unit 641 estimates the negative electrode resistance of each of the secondary batteries 21 to 26 based on the voltage curve acquired by the battery characteristics acquisition unit 63 and the correspondence stored in the correspondence storage unit 51. Then, the degradation level determination unit 65 determines the degradation level of each of the secondary batteries 21 to 26 from the estimated negative electrode resistance. Thereafter, in step S8 shown in FIG. 41, the degradation level determination unit 65 determines the degradation level of each of the secondary batteries 21 to 26 based on the negative electrode resistance estimated by the resistance estimation unit 641. The other steps are the same as those of the embodiment 1, except that in step S11, an actual measurement value of the negative electrode resistance is acquired, and in step S111, the actual measurement value is transmitted from the external terminal 9 to the server 1. The embodiment 15 also achieves the same effects as the embodiment 1.

[0173] Sixteenth Embodiment In a deterioration level determination system 100 according to a sixteenth embodiment, a resistance estimation unit 641 estimates the positive electrode resistance of the secondary batteries 21 to 26, and a deterioration level determination unit 65 determines the deterioration levels of the secondary batteries 21 to 26. In this sixteenth embodiment, nickel-metal hydride batteries are used as the secondary batteries 21 to 26, and a battery characteristic acquisition unit 63 acquires, as the battery characteristics, a voltage curve for a predetermined voltage interval in the low-frequency region. A correspondence relationship between the voltage curve and the positive electrode resistance as the battery characteristics is pre-stored in a correspondence relationship storage unit 51. The deterioration level determination unit 65 then determines the deterioration levels of the secondary batteries 21 to 26 based on the positive electrode resistance estimated by the resistance estimation unit 641 in the positive electrode reaction resistance dominated region. The other components are the same as those in the fifteenth embodiment, and the same reference numerals are used, and their description will be omitted.

[0174] In the degradation level determination method by the degradation level determination system 100 of the sixteenth embodiment, steps S1 to S5 shown in FIG. 41 are performed, similarly to the fifteenth embodiment. Then, in step S77, the resistance estimation unit 641 estimates the positive electrode resistance of each of the secondary batteries 21 to 26 based on the voltage curve acquired by the battery characteristics acquisition unit 63 and the correspondence stored in the correspondence storage unit 51. Then, the degradation level determination unit 65 determines the degradation levels of the secondary batteries 21 to 26 from the estimated positive electrode resistance. Then, in step S8 shown in FIG. 41, the degradation level determination unit 65 determines the degradation levels of the secondary batteries 21 to 26 based on the internal resistance estimated by the resistance estimation unit 641. The other steps are the same as those of the first embodiment, except that in step S11, an actual measurement value of the positive electrode resistance is acquired, and in step S111, the actual measurement value is transmitted from the external terminal 9 to the server 1. The sixteenth embodiment also achieves the same effects as the first embodiment.

[0175] In addition, if a resistance estimation unit 641 is provided instead of the capacitance estimation unit 64 in the external terminal 9 of embodiment 2, and the external terminal 9 is provided with the correspondence relationship storage unit 51, etc., then by performing step S77 in present embodiments 14 to 16 instead of step S7 in Figure 15, the same effect as present embodiments 14 to 16 can be obtained.

[0176] The present disclosure is not limited to the above-described embodiments, and can be applied to various embodiments without departing from the spirit of the present disclosure.

[0177] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

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