Device for determining deterioration level of secondary battery

Abstract

To provide a device for determining a deterioration level of a secondary battery, capable of determining the deterioration level of the secondary battery at high accuracy with a simple structure.SOLUTION: A device for determining a deterioration level 1, includes: a battery information acquisition part 61; a possibility determination part 62; a battery characteristic acquisition part 63; and a deterioration level determination part 65. The battery information acquisition part 61 acquires battery information related to secondary batteries 21 to 26. The possibility determination part 62 determines a possibility of the determination of the deterioration level in each of the secondary batteries 21 to 26 on the basis of the battery information acquired by the battery information acquisition part 61 and a prepared possibility determination criterion. The battery characteristic acquisition part 63 acquires the battery characteristic related to a transition of a battery state in a predetermined voltage section for each of the secondary batteries 21 to 26 in which it is determined by the possibility determination part 62 that the determination of the deterioration level can be performed. The deterioration level determination part 65 determines the deterioration level of each of the secondary batteries 21 to 26 of which the determination of the deterioration level can be performed on the basis of the battery characteristic acquired by the battery characteristic acquisition part 63 or a battery characteristic relation value calculated on the basis of the battery characteristic.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a deterioration level determining device for a secondary battery. [Background technology]

[0002] Conventionally, a battery pack consisting of a combination of a plurality of secondary batteries has been widely used. The secondary batteries deteriorate as the battery pack is used, but the degree of deterioration varies from one secondary battery to another. Therefore, even if the degree of deterioration of some secondary batteries in the battery pack exceeds a standard, the battery pack as a whole cannot be used. In such a case, a usable secondary battery with a low degree of deterioration is taken out from the battery pack and reused. Patent Document 1 discloses a configuration for detecting the degree of deterioration of the secondary batteries in the battery pack. Specifically, the battery pack is discharged until the state of charge (SOC) of the battery pack is equal to or lower than the lower limit of the normal use range, and then each secondary battery module is taken out and the remaining capacity of each secondary battery module is detected. Then, the capacity difference between the secondary battery modules is calculated and compared with a threshold value. If the capacity difference is equal to or higher than a predetermined value, the remaining life of the secondary battery module with a smaller capacity is determined to be equal to or lower than a predetermined value, and the degree of deterioration of each secondary battery module is determined. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Re-tabled publication No. 2012 / 137456 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration disclosed in Patent Document 1, when the variation in the degree of deterioration of the secondary battery modules included in the assembled battery is small, the remaining life, i.e., the degree of deterioration, cannot be calculated with high accuracy. For example, when the degree of deterioration of all the secondary battery modules included in the assembled battery is high or low, the degree of deterioration is unlikely to vary, and the accuracy of detecting the degree of deterioration is poor. On the other hand, the configuration is likely to be complicated in order to remove the secondary battery modules from the assembled battery and individually determine the degree of deterioration of each module with high accuracy.

[0005] The present invention has been made in view of the above problems, and aims to provide a secondary battery deterioration level determination device that is simply configured and capable of determining the deterioration level of a secondary battery with high accuracy. [Means for solving the problem]

[0006] One aspect of the present invention is a deterioration degree determination device (1) for determining a deterioration degree of a secondary battery (21 to 26), comprising: a battery information acquisition unit (61) for acquiring battery information relating to the secondary battery; a determination unit (62) for determining whether or not a deterioration level of each of the secondary batteries can be determined based on the battery information acquired by the battery information acquisition unit and a previously prepared determination criterion; a battery characteristic acquisition unit (63) that acquires battery characteristics related to a transition of a battery state in a predetermined voltage range for the secondary battery for which the deterioration degree determination is determined to be possible by the possibility determination unit; The battery characteristics acquired by the battery characteristics acquisition unit or the battery characteristics calculated based on the battery characteristics a deterioration level determination unit (65) that determines a deterioration level of the secondary battery for which it has been determined that the deterioration level can be determined based on a relation value; Equipped with 、 the battery characteristics include a discharge voltage characteristic based on at least one of a voltage transition when the secondary battery is discharged to a predetermined discharge target voltage and a voltage transition after the secondary battery is discharged to the discharge target voltage and discharging is stopped, The voltage transition is calculated based on at least one of a section capacity of the secondary battery in the voltage section, a ratio of a voltage change of the secondary battery to a capacity change of the secondary battery in the voltage section, a ratio of a voltage change of the secondary battery to an elapsed time in the voltage section, and a capacity ratio of the section capacity of the voltage section to a total discharge capacity when discharged to the discharge target voltage. The present invention relates to a device for determining the deterioration level of a secondary battery. Another aspect of the present invention is a deterioration degree determination device (1) for determining a deterioration degree of a secondary battery (21-26), comprising: a battery information acquisition unit (61) for acquiring battery information relating to the secondary battery; a determination unit (62) for determining whether or not a deterioration level of each of the secondary batteries can be determined based on the battery information acquired by the battery information acquisition unit and a previously prepared determination criterion; a battery characteristic acquisition unit (63) that acquires battery characteristics related to a transition of a battery state in a predetermined voltage range for the secondary battery for which the deterioration degree determination is determined to be possible by the possibility determination unit; a deterioration level determination unit (65) that determines a deterioration level of the secondary battery for which it is determined that the deterioration level can be determined based on the battery characteristics acquired by the battery characteristics acquisition unit or a battery characteristic related value calculated based on the battery characteristics; Equipped with the battery characteristics include a charging voltage characteristic based on at least one of a voltage transition when the secondary battery is charged to a predetermined charging target voltage and a voltage transition after the secondary battery is charged to the charging target voltage and charging is stopped, The voltage trend is calculated based on at least one of the section capacity of the secondary battery in the voltage range, the ratio of the voltage change of the secondary battery to the capacity change of the secondary battery in the voltage range, the ratio of the voltage change of the secondary battery to the elapsed time in the voltage range, and the capacity ratio of the section capacity of the voltage range to the total charging capacity when charged to the target charging voltage, in the secondary battery deterioration degree determination device. Effect of the Invention

[0007] In the deterioration level determination device according to the above aspect, the deterioration level of the secondary battery is determined based on battery characteristics or battery characteristic related values ​​related to voltage transitions in a predetermined voltage section obtained from the secondary battery. Therefore, the deterioration level can be determined in a simple process. Furthermore, by setting a voltage section in which the voltage transitions and the deterioration level of the secondary battery show a high correlation as a voltage section for obtaining the battery characteristics of the secondary battery, the deterioration level of the secondary battery can be determined with high accuracy. Then, before determining the deterioration level of the secondary battery, it is determined whether or not the deterioration level can be determined for each secondary battery, and then the deterioration level is determined for the secondary battery for which it is determined that the deterioration level can be determined. Therefore, by determining the deterioration level for secondary batteries for which the determination accuracy can be sufficiently ensured, the overall determination accuracy can be increased.

[0008] As described above, according to one aspect of the present invention, it is possible to provide a secondary battery deterioration level determining device that is capable of determining the deterioration level with high accuracy using a simple configuration.

[0009] In addition, the symbols in parentheses described in the claims and the means for solving the problems indicate a correspondence with the specific means described in the embodiments described below, and do not limit the technical scope of the present invention. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a conceptual diagram showing the configuration of a deterioration level determining device according to a first embodiment. [Diagram 2] 1A and 1B are conceptual diagrams showing the configuration of a battery pack and a vehicle equipped with the battery pack in a first embodiment; [Diagram 3] 3 is a conceptual diagram showing battery characteristics in the first embodiment. [Figure 4]4 is a conceptual diagram showing a criterion for determining whether or not a test is acceptable in the first embodiment. [Diagram 5] 4 is a flowchart showing a method for determining a deterioration level of a secondary battery in the first embodiment. [Figure 6] FIG. 2 is a flow diagram showing a method for manufacturing a battery pack according to the first embodiment. [Figure 7] 6 is a conceptual diagram showing battery characteristics in the first modified embodiment. [Figure 8] 11 is a conceptual diagram showing battery characteristics in Modification 2. FIG. [Figure 9] 13 is a conceptual diagram showing battery characteristics in Modification 3. FIG. [Figure 10] 13 is a conceptual diagram showing battery characteristics in Modification 4. FIG. [Figure 11] 13 is a conceptual diagram showing battery characteristics in Modification 5. FIG. [Figure 12] 10 is a flowchart showing a method for determining the deterioration level of a secondary battery in the second embodiment. [Figure 13] FIG. 23 is a flowchart showing a method for determining the deterioration level of a secondary battery in the sixth modified embodiment. [Figure 14] FIG. 11 is a flowchart showing a method for determining the deterioration level of a secondary battery in the third embodiment. [Figure 15] FIG. 13 is a conceptual diagram showing the configuration of a deterioration level determining device according to a fourth embodiment. [Figure 16] FIG. 11 is a flowchart showing a method for determining the deterioration level of a secondary battery in the fourth embodiment. [Figure 17] FIG. 13 is a conceptual diagram showing the configuration of a deterioration level determining device according to a fifth embodiment. [Figure 18] FIG. 13 is a conceptual diagram showing the configuration of a deterioration level determining device in a sixth embodiment. [Figure 19] FIG. 13 is a conceptual diagram showing battery characteristics in embodiment 6. [Figure 20] FIG. 23 is a conceptual diagram showing the configuration of a deterioration level determining device in a seventh modified embodiment. [Figure 21] FIG. 13 is a conceptual diagram showing the configuration of a deterioration level determining device according to a seventh embodiment. [Figure 22] FIG. 13 is a conceptual diagram showing battery characteristics in embodiment 7. [Figure 23] 13 is a conceptual diagram showing battery characteristics in Modification 8. FIG. [Figure 24] 13 is a conceptual diagram showing battery characteristics in Modification 9. FIG. [Diagram 25] FIG. 13 is a conceptual diagram showing an SOC-OCV curve of a secondary battery in embodiment 8. [Figure 26] FIG. 20 is a flowchart showing a method for determining the deterioration level of a secondary battery in the eighth embodiment. [Figure 27] 13A is a conceptual diagram showing a discharge curve of a secondary battery, and FIG. 13B is a conceptual diagram showing a charge curve of the secondary battery in the eighth embodiment. [Figure 28] FIG. 23 is a flowchart showing a method for determining the deterioration level of a secondary battery in the ninth embodiment. [Figure 29] FIG. 23 is a conceptual diagram showing an SOC-OCV curve of a secondary battery in the tenth embodiment. [Diagram 30] FIG. 23 is a flowchart showing a method for determining the deterioration level of a secondary battery in the eleventh embodiment. [Diagram 31] 12A is a conceptual diagram showing a discharge curve of a secondary battery, and FIG. 12B is a conceptual diagram showing another discharge curve of the secondary battery in the eleventh embodiment. [Diagram 32] FIG. 23 is a conceptual diagram showing an example of an estimation result in the twelfth embodiment. [Diagram 33] FIG. 23 is a conceptual diagram showing the configuration of a deterioration level determining device in a thirteenth embodiment. [Diagram 34] FIG. 23 is a flowchart showing a method for determining the deterioration level of a secondary battery in a thirteenth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (Embodiment 1) An embodiment of the deterioration level determining device for a secondary battery will be described with reference to FIGS. 1 to 6. FIG. The deterioration level determining device 1 of the first embodiment determines the deterioration level of secondary batteries 21-26, as shown in FIG. The battery information acquisition unit 61 acquires battery information relating to the secondary batteries 21-26. The possibility determining unit 62 determines whether or not it is possible to determine the deterioration level for each of the secondary batteries 21- based on the battery information acquired by the battery information acquiring unit 61 and a possibility determining criterion prepared in advance. The battery characteristics acquisition unit 63 acquires battery characteristics relating to the transition of the battery state in a predetermined voltage range for the secondary batteries 21 to 26 for which the possibility determination unit 62 has determined that the degree of deterioration can be determined. The deterioration level determination unit 65 determines the deterioration level of the secondary batteries 21-26 for which it has been determined that the deterioration level can be determined, based on the battery characteristics acquired by the battery characteristics acquisition unit 63 or the battery characteristic related value calculated based on the battery characteristics.

[0012] The deterioration level determining device 1 for a secondary battery according to the first embodiment will be described in detail below. In the deterioration level determination device 1 shown in FIG. 1, the type of the secondary batteries 21-26 to be determined as the deterioration level is not limited, and known secondary batteries such as nickel-metal hydride batteries and lithium-ion batteries can be used. The secondary batteries may have a single cell or multiple cells. In the first embodiment, as shown in FIG. 2(a), the secondary batteries 21-26 configure a secondary battery module that is an individually detachable module in the assembled battery 20. The number of secondary batteries in the assembled battery 20 is not particularly limited, but is six in the first embodiment, 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 mounted as a battery in a vehicle 100, as shown in FIG. 2(b).

[0013] As shown in FIG. 1, the deterioration level determining device 1 includes a detection unit 3, a storage unit 4, a memory unit 5, a calculation unit 6, a control unit 7, and an update unit 8. The detection unit 3 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 specified voltmeter and detects the voltage values ​​of the secondary batteries 21-26. The current value detection unit 32 is made up of a specified ammeter and detects the value of a current flowing through the secondary batteries 21-26. The open circuit voltages of the secondary batteries 21-26 are configured to be obtained based on the voltage value detected by the voltage value detection unit 31.

[0014] 1 is made 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.

[0015] The storage unit 5 shown in FIG. 1 is made of a non-volatile memory and includes a correspondence storage unit 51 and a reference value storage unit 52. The correspondence storage unit 51 stores a correspondence between battery characteristics and total capacity. The form of the correspondence is not particularly limited, and may be, for example, a calculation formula, a map, a graph, a table, or the like. The correspondence can be created by machine learning using a secondary battery for measurement, based on actual measured values ​​obtained by performing an accelerated deterioration test using a secondary battery for measurement, or by a calculation formula that logically derives the correspondence between battery characteristics and total capacity in a predetermined voltage range using a model of the secondary battery. The correspondence stored in the correspondence storage unit 51 is appropriately set according to the battery characteristics acquired by a battery characteristics acquisition unit 63 described later.

[0016] The total capacity may be the capacity from a completely 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 charging. 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 mounted, or may be a state in which a lower limit voltage defined by a user who uses the deterioration degree determination device 1 is reached. 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 an upper limit voltage defined by the user is reached.

[0017] 1 prestores a possible / probable reference value for determining whether or not the deterioration degree can be determined, which is used in the possible / probable determination unit 62 described below, and a deterioration degree reference value for determining the deterioration degree, which is used in the deterioration degree determination unit 65 described below. Both of these reference values ​​are appropriately set according to the manner of determination in the possible / probable determination unit 62 and the deterioration degree determination unit 65, respectively. In the present embodiment 1, a plurality of reference values ​​are set for the deterioration degree reference value so that the deterioration degree can be determined in five stages.

[0018] 1 includes a charge / discharge control unit 71. The charge / discharge control unit 71 controls charging and discharging so as to charge and discharge the secondary battery 2. The charge / discharge control unit 71 is made up of a calculation device capable of executing a predetermined program.

[0019] 1 is composed of a predetermined calculation device, and has 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. The battery information acquisition unit 61 acquires battery information, which is information related to the secondary batteries 21-26. The battery information may be history information of the secondary batteries 21-26, or alternatively or in addition to this, it may be battery characteristics, which will be described later. In the present embodiment 1, the battery information acquisition unit 61 acquires the battery characteristics acquired by the battery characteristics acquisition unit 63, which will be described later, as the battery information.

[0020] The possibility determination unit 62 shown in FIG. 1 determines whether or not the deterioration level can be determined 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 value calculated from the battery information, and the possibility determination criterion stored in the reference value storage unit 52. In the first embodiment, the possibility determination unit 62 determines whether or not the deterioration level can be determined for each of the secondary batteries 21 to 26 based on the battery information related value calculated from the battery information acquired by the battery information acquisition unit 61 and the possibility determination criterion. A secondary battery determined to be unable to determine its deterioration level is outside the range of training data used when defining the deterioration level determination criterion in the deterioration level determination unit 65 described later, and is in an unlearned range. Therefore, for the secondary battery, since there is a possibility that the determination accuracy cannot be sufficiently ensured in the current deterioration level determination, the deterioration level determination described later is not performed. As a result, by determining the deterioration level for secondary batteries for which the determination accuracy can be sufficiently ensured, the overall determination accuracy can be increased. For secondary batteries whose degradation level was not determined in this degradation level determination, the total capacity can be measured separately by the update unit 8 described below and used as training data for defining the determination criteria to be used in the next and subsequent degradation level determinations. This allows the determination criteria to be updated in accordance with changes over time in the secondary batteries, thereby maintaining high determination accuracy.

[0021] The feasibility determination criterion used in the feasibility determination unit 62 can be created by machine learning using a secondary battery for measurement, created based on test measurement values ​​obtained by performing an accelerated deterioration test using a secondary battery for measurement or actual measurement values ​​obtained from a used secondary battery, or created by a relational expression that logically derives the feasibility determination criterion using a model of a secondary battery. The feasibility determination criterion 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, a predetermined range calculated by machine learning the correspondence relationship between battery information A and battery information B obtained from a secondary battery for measurement as training data can be used as the feasibility determination criterion. That is, the distance between data for the training data can be used as the feasibility determination criterion. The distance between data can be specified based on the Mahalanobis distance, the Euclidean distance, the Manhattan distance, the Chebyshev distance, or the like.

[0022] In the first embodiment, the possibility determination unit 62 is configured to perform the possibility determination based on the 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 by using a relational expression related to a plurality of pieces of battery information set in advance. 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 the secondary battery for which the first deterioration level determination is determined to be impossible.

[0023] The battery characteristic acquisition unit 63 acquires the battery characteristics of the secondary batteries 21-26 in a predetermined voltage section. The battery characteristics of the secondary batteries 21-26 can be characteristics based on, for example, the voltage transition or temperature transition of the secondary battery 2 in the predetermined voltage section Vs. The voltage transition can be calculated based on at least one of the section capacity of the secondary batteries 21-26 in the predetermined voltage section, the ratio of the voltage change of the secondary batteries 21-26 to the capacity change of the secondary battery 2 in the predetermined voltage section, and the ratio of the voltage change of the secondary batteries 21-26 to the elapsed time in the predetermined voltage section. The predetermined voltage section can be a voltage section in which the deterioration degree of the secondary batteries 21-26 and the transition of the battery state show a correlation. The voltage section can be set based on the type and configuration of the secondary batteries 21-26, or can be derived by machine learning using the secondary batteries. The battery characteristic acquisition unit 63 may acquire the absolute value of the acquired value as the battery characteristic. The predetermined voltage section 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 appropriate.

[0024] In the present embodiment 1, the discharge voltage characteristic is used as the battery characteristic. The discharge voltage characteristic is calculated based on the voltage transition when the secondary battery 2 is discharged to a discharge target voltage VP, as shown in Fig. 3. The discharge target voltage VP is not particularly limited, but may 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.

[0025] The above-mentioned voltage trend can be calculated based on at least one of, for example, the section capacity of the secondary battery 2 in a specified voltage section Vs, the ratio of the voltage change of the secondary battery 2 to the capacity change of the secondary battery 2 in the specified voltage section Vs, and the ratio of the voltage change of the secondary battery 2 to the elapsed time in the specified voltage section Vs.

[0026] The predetermined voltage section Vs can be a voltage section in which the degree of deterioration of the secondary battery 2 and the transition of the battery state show a correlation. Such a voltage section Vs can be set based on the type and configuration of the secondary battery 2, or derived by machine learning using the secondary battery 2. For example, in the first embodiment, FIG. 3 2, the predetermined voltage section Vs is set to a section from voltage value V1 to V2. This 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.

[0027] 1 estimates the total capacity of the secondary battery 2 for which the deterioration degree 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 estimation of the total capacity can utilize a prediction model such as a regression equation created based on previously acquired training data, and for example, linear regression, LASSO regression, Ridge regression, decision tree, support vector regression, etc. can be utilized.

[0028] 1 determines the degree of deterioration of the secondary battery 2 based on the battery characteristics or a battery characteristic-related value. The battery characteristic-related value is a value calculated based on the battery characteristics, and in the present embodiment 1, the estimation result of the capacity estimation unit 64 is used as the battery characteristic-related value. Therefore, in the present embodiment 1, 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 performed by comparing the estimation result of the capacity estimation unit 64 with a reference value stored in advance in the reference value storage unit 52.

[0029] 1 is composed of a predetermined calculation device, and includes a reference value update unit 81. The reference value update unit 81 updates the acceptability determination criteria and the deterioration degree determination criteria stored in the reference value storage unit 52. This updating can be performed by having the charge / discharge control unit 71 charge / discharge a secondary battery for which it has been determined that the deterioration degree cannot be determined by the acceptability determination unit 62 described above, to obtain an actual measurement value of the total capacity, and then using this as additional training data to update the acceptability determination criteria and the deterioration degree determination criteria stored in the reference value storage unit 52.

[0030] The flow of the deterioration level determining method performed by the deterioration level determining device 1 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 a module are removed from the used battery pack 20 shown in Fig. 2(a). Then, in step S2, the charge / discharge control unit 71 discharges the remaining capacity of each of the secondary batteries 21-26 individually. 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, the secondary batteries 21-26 may have a memory effect, but the memory effect is also released at the same time for those of the secondary batteries 21-26 that have been discharged to the discharge target voltage VP or a voltage close to this voltage.

[0031] Then, in conjunction with discharging the remaining capacity in step S2 shown in Fig. 5, the battery characteristics of each of the secondary batteries 21-26 are acquired by the battery characteristics acquisition unit 63 in step S3 shown in Fig. 5. In the first embodiment, the above-mentioned discharge voltage characteristics are acquired as the battery characteristics. As described above, the discharge voltage characteristics are based on the voltage transitions in the predetermined voltage interval Vs of each of the secondary batteries 21-26 shown in Fig. 3.

[0032] In the first embodiment, as shown in FIG. 3, the battery characteristic acquisition unit 63 acquires the voltage transition from the discharge start T0 to the discharge end T P1 A voltage time change is obtained, which indicates the relationship of the voltage change with respect to the passage of time up to the time when the battery 21 is discharged. Then, a differential value at the voltage VA within a predetermined voltage section Vs, i.e., the slope of the tangent at the voltage VA indicated by reference symbol 21A in the graph of the voltage time change shown in FIG. 3, is calculated, and this is taken 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 a predetermined voltage section Vs indicated by reference symbol 22A is calculated, and this is taken as the discharge voltage characteristic of the second secondary battery 22. Similarly, for the third to sixth secondary batteries 23 to 26, voltage time changes are obtained as the voltage transition, and a differential value at the voltage VA is calculated to take the respective discharge voltage characteristics.

[0033] In the first embodiment, the voltage change over time 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, but instead, the ratio of the voltage change between two points in the voltage change over time derived as the voltage transition, that is, the slope of the line passing through the two points in the graph of the voltage change over time, may be calculated and used as the discharge voltage characteristic. For example, the start time T of the voltage section Vs and the start time T of the voltage section 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 In addition to adopting these two points, the other secondary batteries 22 to 26 can also adopt the same two points.

[0034] 5, the battery information acquisition unit 61 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 deterioration level can be determined. Specifically, the feasibility determination unit 62 determines whether the deterioration level can be determined based on whether the data distance between the feasibility determination criterion stored in the reference value 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.

[0035] If the acquired battery information is not within the acceptability judgment criteria, acceptability judgment unit 62 judges that it is not possible to judge the deterioration level, and proceeds to No in step S5 shown in Fig. 5. Then, in step S6, for those of secondary batteries 21-26 for which it is not possible to judge the deterioration level, no deterioration level judgment is performed, and the process proceeds to step S9 described below.

[0036] 5, if the acquired battery information is within the possibility determination criterion, the possibility determination unit 62 determines that the deterioration degree can be determined, and proceeds to Yes in step S5. Then, in step S7, the capacity estimation unit 64 estimates the total capacity, i.e., the full charge capacity or the full discharge capacity, of the secondary batteries 21-26 based on the battery characteristics acquired by the battery characteristics acquisition unit 63. In the present embodiment 1, the capacity estimation unit 64 estimates the total capacity of the secondary batteries 21-26 from the discharge voltage characteristics as the battery 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.

[0037] Then, in step S8 shown in Fig. 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. As a result, the process proceeds to step S9, and the current deterioration level determination is terminated. Then, the process proceeds to symbol A, and in step S10, the update unit 8 determines whether or not there was a secondary battery for which the possibility determination unit 62 determined in step S5 that the deterioration level could not be determined. If it is determined that there is no secondary battery for which the deterioration level is not to be determined, the process proceeds to No in step S10, and this control flow is terminated. On the other hand, if it is determined in step S5 that there is a secondary battery for which the deterioration level is not to be determined, the process proceeds to Yes in step S10.

[0038] 5, for secondary batteries for which the degree of deterioration is not to be determined, charging and discharging is performed by the charge / discharge control unit 71 to measure the actual measured value of the total capacity. Then, in step S12, the reference value update unit 81 uses the actual measured value as additional training data to update the pass / fail judgment criteria and the deterioration degree judgment criteria stored in the reference value storage unit 52. Both of these reference values ​​are to be used for the next and subsequent deterioration degree judgments.

[0039] Next, a method for manufacturing a rebuilt battery pack 20 by assembling a new battery pack 20 using secondary batteries 2 constituting a module removed from a used battery pack 20 will be described below. First, in step S13 shown in FIG. 6, a plurality of secondary batteries 2 taken out 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 in the case of acquiring the battery characteristics in the deterioration degree determination device 1 of the present embodiment 1. After that, in step S15, the secondary batteries 2 are ranked based on the battery characteristics or a battery characteristic related value calculated based on the battery characteristics. In the present embodiment 1, the total capacity of the secondary battery 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 degree of the secondary battery 2 calculated from the total capacity is within a predetermined range. Then, in the present embodiment 1, the absolute value of the deterioration degree is divided into five predetermined ranges, and the absolute value of the deterioration degree is ranked in order from the smallest to the smallest, that is, A rank, B rank, C rank, D rank, and E rank. The criteria for ranking can be set appropriately.

[0040] Next, in step S16 shown in FIG. 6, the secondary batteries 21 to 26 are sorted based on the rank. In the present embodiment 1, the secondary batteries 21 to 26 are sorted by rank. As a result, the secondary batteries 2 in the same rank have the same degree of deterioration. Then, in step S17, the secondary batteries 2 in the same rank are combined to assemble the battery pack 20 to create a rebuilt product. As a result, the absolute values ​​of the deterioration degrees of the secondary batteries 2 included in the rebuilt battery pack 20 are the same, and the difference in the deterioration degrees can be made equal to or less than a predetermined reference value. The reference value of the difference in the deterioration degrees can be appropriately set according to the ranking criteria. In the present embodiment 1, the battery pack 20 is created from the secondary batteries 2 in the same rank, but 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 the secondary batteries 2 in the A rank and the B rank. The secondary batteries 2 ranked in the lowest E rank may be discarded as unusable, or may be disassembled and recycled.

[0041] 6, in the first embodiment, supplementary charging is then performed for each assembled battery 20. As a result, the secondary batteries 21 to 26 become usable as the assembled battery 20.

[0042] Next, the effects of the deterioration level determining device 1 of the first embodiment will be described in detail. In the deterioration level determination device 1 of the first embodiment, the deterioration level of the secondary battery is determined based on the battery characteristics or battery characteristic related values ​​related to the voltage transition in a predetermined voltage section acquired from the secondary battery 2. Therefore, the deterioration level can be determined in a simple process. Furthermore, by setting a voltage section in which the voltage transition of the secondary battery 2 and the deterioration level show a high correlation as the voltage section for acquiring 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 the secondary battery 2, it is determined whether or not the deterioration level can be determined for each secondary battery 2, and the deterioration level is determined for the secondary battery 2 for which the deterioration level is determined to be capable of being determined. Therefore, by determining the deterioration level for the secondary battery 2 for which the determination accuracy can be sufficiently ensured, the overall determination accuracy can be increased.

[0043] In addition, in the first embodiment, the possibility determination unit 62 performs the possibility determination based on a result of comparison between the battery information relation value calculated from the battery information acquired by the battery information acquisition unit 61 and the possibility determination criterion using a relational expression related to a plurality of pieces of battery information set in advance. This makes it possible to improve the determination accuracy by appropriately adjusting the relational expression.

[0044] The deterioration level determination device 1 of the first embodiment can provide an assembled battery 20 including a plurality of secondary batteries 2 having a usage history, in which the battery characteristics relating to the transition of the battery state in a predetermined voltage section Vs of the secondary batteries 2 or the battery characteristic related value calculated based on the battery characteristics are within a predetermined range. In such an assembled battery as a rebuilt product, it is possible to provide an assembled battery 20 with small variations in battery characteristics. By setting a voltage section Vs in which the voltage transition of the secondary batteries 2 and the deterioration level have a high correlation as the voltage section Vs for acquiring the battery characteristics of the secondary batteries 2, the variation in the deterioration level of the secondary batteries 2 included in the assembled battery 20 can be reduced, thereby making it possible to extend the life and improve the quality of the assembled battery 20.

[0045] In the first embodiment, the capacity estimation unit 64 estimates the total capacity of the secondary batteries 21-26 from the battery characteristics acquired by the battery characteristics acquisition unit 63, and the deterioration degree determination unit 65 determines the deterioration degree of the secondary batteries 21-26 based on the estimation result, but instead, the deterioration degree determination unit 65 may determine the deterioration degree of the secondary batteries 21-26 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 degree determination unit 65 may determine the deterioration degree based on the absolute value. Also, the deterioration degree determination unit 65 may determine the deterioration degree of the secondary batteries 21-26 based on the difference between the battery characteristics acquired by the battery characteristics acquisition unit 63.

[0046] In the first embodiment, the secondary batteries 21-26 are classified and assembled into the battery pack 20 so that the deterioration levels of the secondary batteries 21-26 are within a predetermined range. However, the secondary batteries 21-26 may be classified and assembled into the battery pack 20 so that the deterioration levels of the secondary batteries 21-26 and the difference between the deterioration levels are within a predetermined range.

[0047] In the first embodiment, the battery characteristics are discharge voltage characteristics based on the voltage transitions in the predetermined voltage sections Vs1 and Vs2 of the secondary batteries 21-26. If the secondary batteries 21-26 are nickel-metal hydride batteries, they may be discharged for the purpose of removing the memory effect when they are reused after use. By obtaining the discharge voltage characteristics during the discharge, the work process for reusing the secondary batteries 21-26 can be simplified.

[0048] In the first embodiment, the discharge voltage characteristic is calculated based on the voltage transition during discharge of the secondary battery 2. However, instead of or in addition to this, the discharge voltage characteristic may be calculated based on the voltage transition during voltage relaxation when the secondary battery 2 is discharged to the discharge target voltage VP and the discharge is stopped, and then the voltage returns to the open circuit voltage. For example, as in the first modified embodiment shown in FIG. 7, the discharge voltage characteristic is calculated based on the voltage transition during voltage relaxation when the secondary battery 21 is discharged to the discharge target voltage VP and the discharge is stopped, and then the discharge voltage characteristic is calculated based on the voltage transition during voltage relaxation when the secondary battery 21 is discharged to the discharge target voltage VP and then the discharge is stopped. P1 Based on the voltage transition in the predetermined voltage section Vs in the subsequent voltage relaxation, a differential value at a predetermined voltage VA indicated by reference symbol 21A can be calculated to obtain the discharge voltage characteristic. P2 Based on the voltage transition in the predetermined voltage section Vs in the subsequent voltage relaxation, a differential value at a predetermined voltage VA indicated by reference symbol 22A can be calculated to obtain the discharge voltage characteristics, and similarly, discharge voltage characteristics based on the voltage transition in the predetermined voltage section Vs in the voltage relaxation can be obtained for the other secondary batteries 23 to 26 (not shown). In this case as well, the same effects as those of the first embodiment can be obtained.

[0049] Moreover, 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 the battery characteristic related values, and a deterioration level determination unit 65 determines the deterioration levels of the secondary batteries 21-26 based on the estimation results of the capacity estimation unit 64. This makes it possible to detect the deterioration levels of the secondary batteries 21-26 with high accuracy.

[0050] In the first embodiment, the rate of voltage change of the secondary battery 2 with respect to the elapsed time in a predetermined voltage section Vs, that is, the differential value of the voltage change over time is calculated as the discharge voltage characteristic. This makes it possible to easily and precisely determine the deterioration degree of the secondary battery 2.

[0051] 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 section Vs as the voltage transition, the battery characteristics acquisition unit 63 may calculate the amount of capacity change of each of the secondary batteries 21-26 in the predetermined voltage section Vs as a section capacity Qp, as shown in modified embodiment 2 in Fig. 8, and use this as the discharge voltage characteristic. The section capacity Qp can be calculated from the current value flowing through the secondary batteries 21-261-26 in the voltage section 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 easily and with high accuracy based on the discharge voltage characteristic.

[0052] In addition, all sections T0 to T P1 , T0~T P2 8 as the capacity of the secondary battery 2, a capacity ratio that is a ratio of the section capacity Qp to the total charge / discharge capacity Qt may be calculated, and this may be used as the discharge voltage characteristics. Alternatively, instead of the total charge / discharge capacity Qt, a specific section capacity Qt' that is a capacity of a specific voltage section including a voltage section for calculating the battery characteristics may be calculated, and a capacity ratio that is a ratio of the section capacity Qp to the specific section capacity Qt' may be calculated, and this may be used as the discharge voltage characteristics. In this case as well, the degree of deterioration of the secondary battery 2 can be determined easily and with high accuracy based on the discharge voltage characteristics.

[0053] 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 shown in the third modified embodiment in FIG. 9, the voltage transition is the capacity Q0 at the start of discharge to the capacity Q p1Alternatively, a voltage-capacity change indicating the relationship between the voltage change and the capacity up to may be obtained. Then, a differential value at the voltage VA within a predetermined voltage section Vs, i.e., the gradient of the tangent at the voltage VA in the graph of the voltage-capacity change, may be calculated, and this may be used as the discharge voltage characteristic of the first secondary battery 21. In this case as well, the same effects as those of the first embodiment may be achieved.

[0054] In this embodiment 1, the battery characteristics are calculated and acquired in the battery characteristics acquisition unit 63 provided in the deterioration level determination device 1, but instead, the deterioration level determination device 1 may have an external input unit, and the battery characteristics may be calculated using an external arithmetic device, and the battery characteristics may be input to the battery characteristics acquisition unit 63 via the external input unit, thereby causing the battery characteristics acquisition unit 63 to acquire the battery characteristics.

[0055] In the first embodiment, the discharge voltage characteristic is used as the battery characteristic, but in addition, as in the fourth modified embodiment shown in Fig. 10, the battery characteristic may include a charge voltage characteristic based on the voltage transition when the secondary batteries 21-26 are charged to a predetermined charge target voltage VQ. 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 those in the first embodiment.

[0056] In the fourth 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 the charge voltage characteristic. That is, as shown in FIG. P1 , T P2 From the start of charging to the end of charging T Q1 , T Q2A voltage time change is obtained, which indicates the relationship of the voltage change with respect to the passage of time up to the time when the voltage VB is changed. Then, a differential value at the voltage VB within a predetermined voltage section VsB, i.e., the slope of the tangent at the voltage VB indicated by reference symbol 21B in the graph of the voltage time change shown in FIG. 10, is calculated, and this is set as the charging voltage characteristic of the first secondary battery 21. As shown in FIG. 10, a voltage time change is also obtained as a voltage transition for the second secondary battery 22, and a differential value at the voltage VB within a predetermined voltage section Vs indicated by reference symbol 22B is calculated, and this is set as the discharging voltage characteristic of the second secondary battery 22. Similarly, for the third to sixth secondary batteries 23 to 26, a voltage time change is also obtained as a voltage transition, and a differential value at the voltage VB is calculated to set each of the charging voltage characteristics. The predetermined voltage section VsB is a section from voltage value V3 to V4, and is a section in which the difference in the charging voltage characteristic is significant depending on the degree of deterioration of the secondary battery 2.

[0057] The charge voltage characteristic may be calculated as the ratio of voltage change between the start time TB11, TB21 and the end time TB12, TB22 of a predetermined voltage section VsB, as in the case of calculating the discharge voltage characteristic in the above-mentioned first embodiment, as the section capacity Qp in the voltage section VsB, or as the total section T P1 ~T Q1 , T P2 ~T Q2 In other words, the total charge / discharge capacity QT when the battery is charged up to the charge target voltage VQ may be calculated, and the ratio of the section capacity Qp to the total charge / discharge capacity QT may be used.

[0058] In the fourth 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. This makes it possible to determine the degree of deterioration of the secondary battery 2 with even greater accuracy.

[0059] When a rebuilt battery pack 20 is manufactured using the deterioration level determination device 1 of this modified embodiment 4, each secondary battery 2 is charged before assembling the battery pack 20, and therefore there is no need to supplementarily charge the battery pack 20 in step S15 in FIG. 6.

[0060] In addition, in this modified embodiment 4, the battery characteristics acquisition unit 63 acquires the discharge voltage characteristics and then acquires the charging voltage characteristics by discharging the secondary battery 2 and then charging it, but this is not limited to the above, and the battery characteristics acquisition unit 63 may acquire the charge voltage characteristics and then acquire the discharge voltage characteristics by charging the secondary battery and then discharging it.

[0061] In addition, in the fourth modified embodiment, the battery characteristic acquisition unit 63 acquires both the discharge voltage characteristic and the charge voltage characteristic, but instead, only the charge voltage characteristic may be acquired. In this case, the determination accuracy may be inferior to the case where both the discharge voltage characteristic and the charge voltage characteristic are acquired. On the other hand, when the secondary batteries 21 to 26 are nickel-metal hydride batteries, the memory effect may occur, and when only the discharge voltage characteristic is acquired, the discharge voltage characteristic may have a variation in voltage transition due to the influence of the memory effect, which may suppress 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 release of the memory effect, so that the influence of the memory effect is small, and therefore the determination accuracy can be expected to be improved.

[0062] In addition, the charge voltage characteristic in the present modified embodiment 4 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 embodiment 5 shown in FIG. 11, Q1 Based on the voltage transition in the predetermined voltage section VsB in the subsequent voltage relaxation, a differential value at a predetermined voltage VB indicated by reference numeral 21B may be calculated as the charging voltage characteristic. Q2 Based on the voltage transition in the predetermined voltage section VsB in the subsequent voltage relaxation, a differential value at a predetermined voltage VB indicated by reference numeral 22B may be calculated as the charging voltage characteristic. In this case, the same effects as those of the first embodiment can be obtained.

[0063] As described above, according to the above embodiment, it is possible to provide the secondary battery deterioration level determining device 1 that can improve the workability when determining the deterioration level of the secondary batteries 21 to 26 constituting the battery pack 20.

[0064] In the fourth modified embodiment, similarly to the modified embodiment of the first embodiment, the deterioration degree determination unit 65 may determine the deterioration degree of the secondary battery 2 based on the battery characteristics acquired by the battery characteristics acquisition unit 63 without estimating the total capacity. The battery characteristics acquisition unit 63 may acquire the absolute value of the acquired value as the battery characteristics, and the deterioration degree determination unit 65 may determine the deterioration degree based on the absolute value. The deterioration degree determination unit 65 may determine the deterioration degree of the secondary battery 2 based on the difference in the battery characteristics acquired by the battery characteristics acquisition unit 63. The secondary batteries 2 may be classified and assembled into the battery pack 20 so that the deterioration degree of the secondary battery 2 and the difference in the deterioration degree are within a predetermined range.

[0065] (Embodiment 2) In the deterioration degree determination device 1 of the above-mentioned embodiment 1, 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, but in the embodiment 2, the battery information is acquired as the history information of the secondary battery 2. The history information of the secondary batteries 21-26 may be the charge and discharge electricity amounts, battery temperatures, state of charge (SOC), number of equalizations, outside air temperature, period of use of the device in which the secondary battery is mounted, maximum values, minimum values, average values, and accumulated values ​​of the temperature and the like in a predetermined period, etc. 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 in the embodiment 1, and the same reference numerals as those in the embodiment 1 are used, and the description thereof will be omitted.

[0066] In the flow of deterioration level determination in the second embodiment, as shown in Fig. 12, first, step S1 is performed in the same manner as in the first embodiment. Then, the process proceeds to step S40, where the battery information acquisition unit 61 attempts to acquire battery information on the secondary batteries 21-26. In the second embodiment, the battery information acquisition unit 61 attempts to acquire, for example, history information on the amount of charged electricity in each of the secondary batteries 21-26 as battery information A, and attempts to acquire the temperature history of each of the secondary batteries 21-26 as battery information B. Note that the types of history information that are attempted to be acquired here are not limited to these.

[0067] 12, it is determined whether or not the battery information A and B have been acquired by the battery information acquisition unit 61. If the battery information A and B have not been acquired in step S41, the process proceeds to No in step S41, and in step S42, it is determined that the measurement is defective, and the flow is ended without determining the degree of deterioration of the secondary battery 2.

[0068] On the other hand, if the battery information can be acquired in step S41 shown in Fig. 12, the process proceeds to Yes in step S41. Then, in step S5, the possibility determination unit 62 determines whether the deterioration level can be determined, as in the case of embodiment 1. For any of the secondary batteries 21-26 whose acquired battery information does not fall within the possibility determination criterion, it is determined that the deterioration level cannot be determined, and, as in the case of embodiment 1, steps S6 and S9 are performed, followed by the process proceeding to symbol A in Fig. 5, and steps S10-S12 are performed, ending the flow.

[0069] On the other hand, in step S5 shown in Fig. 12, for those of the secondary batteries 21-26 whose acquired battery information falls within the feasibility determination criterion, the feasibility determination unit 62 determines that it is possible to determine the degree of deterioration, and proceeds to Yes in step S5. Then, in step S20, for those of the secondary batteries 21-26 whose degree of deterioration is determined to be possible, the remaining capacity is discharged individually, similar to step S5 of 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.

[0070] Thereafter, in step S21, for those batteries for which it is determined that the deterioration degree can be determined, the discharge voltage characteristics are acquired as the battery characteristics in the same manner as in step S3 of the first embodiment shown in Fig. 5. Then, steps S7 to S12 are carried out in the same manner as in the first embodiment, and the flow ends.

[0071] In the second embodiment, the battery information acquisition unit 61 acquires, as the battery information, history information on the secondary batteries 21 to 26. As a result, whether or not the deterioration degree can be determined is determined based on the history information of the secondary batteries 21 to 26, so that the accuracy of the determination can be improved.

[0072] In the deterioration level determination device 1 of the above-mentioned embodiment 1, 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, while in the deterioration level determination device 1 of embodiment 2, the battery information acquisition unit 61 acquires the history information of the secondary battery 2 as the battery information. Instead of this, the deterioration level determination device 1 of modified embodiment 6 is configured to acquire both the battery characteristics acquired by the battery characteristics acquisition unit 63 and the history information of the secondary battery 2 as the battery information. The other configurations are similar to those of embodiment 1 and embodiment 2, and the same reference numerals as those of embodiment 1 and embodiment 2 are used, and the description thereof will be omitted.

[0073] In the flow of determining the deterioration level in the sixth modified embodiment, as shown in FIG. 13, first, steps S1, S40, and S41 are performed in the same manner as in the second embodiment. If the battery information cannot be acquired in step S41, the following is performed in the same manner as in the second embodiment: The flow proceeds to No in step S41, and the measurement is deemed to be unsatisfactory in step S42, without determining the deterioration level of the secondary battery 2, and the flow ends.

[0074] 13, if the battery information is acquired, the remaining capacity of the secondary battery for which the battery information was acquired is discharged and, if the secondary battery is a nickel-metal hydride battery, the memory effect is also released at the same time in step S20, as in embodiment 2. Then, in step S21, the battery characteristics are acquired as in embodiment 2, and the process proceeds to step S50.

[0075] In step S50 shown in Fig. 13, the possibility determination unit 62 determines whether or not the deterioration level can be determined based on the battery characteristics and history information of the secondary batteries 21-26 as battery information and the possibility determination criterion. For the secondary batteries 21-26 whose acquired battery information is not within the possibility determination criterion, it is determined that the deterioration level cannot be determined, and similarly to the first embodiment, steps S6 and S9 are performed, proceeding to symbol A in Fig. 5, steps S10-S12 are performed, and the flow is terminated. On the other hand, for the secondary batteries 21-26 whose deterioration level is determined to be capable of being determined, steps S7-S9 are performed, similarly to the first embodiment, proceeding to symbol A in Fig. 5, steps S10-S12 are performed, and the flow is terminated.

[0076] According to the sixth modified embodiment, the battery information used to determine whether the deterioration level 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 deterioration level can be determined with higher accuracy. Note that the sixth modified embodiment also provides the same advantageous effects as the first and second embodiments.

[0077] (Embodiment 3) The deterioration level determination device 1 of the third embodiment has the same configuration as that of the second embodiment shown in Fig. 12. In the third embodiment, a first feasibility determination criterion D1 and a second feasibility determination criterion D2 are stored in the reference value storage unit 52. In the third embodiment, the first feasibility determination criterion D1 is stored as the inter-data distance D1 in the form of a Mahalanobis distance D1, and the second feasibility determination criterion D2 is stored as the inter-data distance D2 in the form of a Mahalanobis distance, and the relationship between the two is D1. <D2としている。

[0078] In the third 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.

[0079] Next, a flow of a deterioration degree determining method by the deterioration degree determining device 1 of the present embodiment 3 will be described below with reference to Fig. 14. In the present embodiment 3, the same components as those in the embodiment 2 shown in Fig. 12 are denoted by the same reference numerals and the description thereof will be omitted. In the flow of the present embodiment 3, instead of the case of the embodiment 2 shown in Fig. 12, as shown in Fig. 14, for those of the secondary batteries 21-26 for which battery information has been acquired in step S41, the process proceeds to step S41Yes, and in step S51, the possibility determination unit 62 determines whether it is possible to determine the deterioration 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 deterioration level, the process proceeds to step S51Yes, and steps S22 and S23 similar to steps S20 and S21 in the embodiment 2 are performed.

[0080] 14, the capacity estimation unit 64 estimates the total capacity, i.e., the full charge capacity or the full discharge capacity, of the secondary batteries 21-26 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 relationship between the battery characteristics and the total capacity based on the prediction model stored in the correspondence storage unit 51. Then, as in the second embodiment, the degree of deterioration is determined in step S8, step S9 is performed, and the flow proceeds to symbol A in FIG. 5, steps S10-S12 are performed, and the flow ends.

[0081] 14, for those of the secondary batteries 21-26 for which it is not possible to determine the degree of deterioration based on the first feasibility determination criterion D1, the process proceeds to No in step S51. Then, in step S52, for those of the secondary batteries 21-26 for which it is determined in step S51 that it is not possible to determine the degree of deterioration, the feasibility determination unit 62 determines whether it is possible to determine the degree of deterioration based on the second feasibility 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 S24 and S25 similar to steps S20 and S21 in the second embodiment are performed.

[0082] Thereafter, in step S72 shown in FIG. 14, the capacity estimation unit 64 estimates the total capacity, i.e., the full charge capacity or the full discharge capacity, for the secondary batteries 21-26 for which it is determined in step S52 that the deterioration degree can be determined, from the battery characteristics acquired by the battery characteristics acquisition unit 63, based on the second correspondence between the battery characteristics based on the prediction model stored in the correspondence storage unit 51. Then, the deterioration degree is determined in step S8 as in the second embodiment, and the process proceeds to step S9 to end the determination of the deterioration degree this time. On the other hand, for the secondary batteries 21-26 for which it is determined in step S52 that the deterioration degree cannot be determined, the process proceeds to No in step S52, and the process proceeds to steps S6 and S9 as in the first embodiment to end the determination of the deterioration degree this time. After step S9, the process proceeds to symbol A in FIG. 5, where steps S10 to S12 are performed, and the flow ends.

[0083] In the deterioration degree determination device 1 of the third embodiment, the first and second possible / not possible determination criteria D1 and D2 are used as the multiple possible / not possible determination criteria, and the first and second correspondence relationships are used as the multiple correspondence relationships suitable for the items that are determined to be possible to determine the deterioration degree by the respective possible / not possible determination criteria. This provides high consistency between the criteria for determining the deterioration degree and the criteria for determining the deterioration degree, and allows the deterioration degree to be determined with higher accuracy. Note that the present embodiment also provides the same effects as the first embodiment.

[0084] (Embodiment 4) In the deterioration degree determination device of the fourth embodiment, as shown in FIG. 15, the calculation unit 6 further includes a vehicle information acquisition unit 66. Examples of the vehicle information include the vehicle model of the vehicle 100, the product number of the assembled battery or secondary battery module, the position of the module in the assembled battery, the year of manufacture, the period of use, and the mileage of the vehicle 100, and the location of the dealer of the vehicle 100. The reference value storage unit 52 stores a vehicle information standard as a vehicle information determination standard for determining whether or not the deterioration degree can be determined. In the fourth embodiment, a plurality of specific vehicle models are stored as the vehicle information. The correspondence storage unit 51 stores correspondences corresponding to the specific vehicle models. The other configurations are the same as those of the first embodiment shown in FIG. 1 and the second embodiment not shown, and the same reference numerals are used to omit the description thereof.

[0085] Next, the flow of the degradation level determination method by the degradation level determination device 1 of the present embodiment 4 will be described below. In the present embodiment 4, the same reference numerals are used for the same parts as those in the embodiment 2 shown in Fig. 12, and the description thereof will be omitted. In the flow of the present embodiment 4, instead of step S40 of the embodiment 2 shown in Fig. 12, the flow proceeds to step S43 after step S1 as shown in Fig. 16, and the vehicle information acquisition unit 66 acquires vehicle information of the vehicle 100 on which the assembled battery 20 is mounted. The vehicle information is not limited, but in the present embodiment 4, the vehicle model of the vehicle 100 is acquired.

[0086] 16, the feasibility determination unit 62 determines whether or not the vehicle information acquired by the vehicle information acquisition unit 66 corresponds to the vehicle information standard. In the fourth embodiment, it is determined whether or not the vehicle model acquired by the vehicle information acquisition unit 66 corresponds to a specific vehicle model stored in the reference value storage unit 52. If it is determined in step S44 that the vehicle model does not correspond to a specific vehicle model, the process proceeds to No in step S44, and the flow ends without determining the degree of deterioration in step S42 as in the second embodiment.

[0087] On the other hand, in step S44 shown in FIG. 16, if it is determined that the acquired vehicle information corresponds to the vehicle information standard, the process proceeds to Yes in step S44. Then, steps S40 to S42, steps S5 to S6, and steps S20 to S21 are performed in the same manner as in the second embodiment. After step S21, for the secondary batteries determined to be capable of determining the degree of deterioration, in step S73, the capacity estimation unit 64 estimates the total capacity according to the vehicle information. That is, the estimation formula used to estimate the total capacity in the capacity estimation unit 64 is changed according to the vehicle information. Then, in step S8, the deterioration degree determination unit 65 determines the deterioration degree of the secondary batteries 21 to 26 based on the estimation result of the total capacity. After step S8 and step S6, the process proceeds to step S9 as in the second embodiment to end the determination of the deterioration degree this time. Then, the process proceeds to symbol A in FIG. 5, and steps S10 to S12 are performed to end the flow.

[0088] According to the deterioration degree determination device 1 of the present embodiment 4, 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, and the estimation accuracy is further improved. Note that the deterioration degree determination device 1 of the present embodiment 4 can also achieve the same effects as those of the present embodiment 1.

[0089] (Embodiment 5) In the deterioration degree determination device 1 of the fifth 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. 17. The impedance characteristics acquisition unit 67 has a configuration for performing complex impedance measurement, and is configured to be able to measure the impedance of the secondary batteries 21 to 26. The other configurations are the same as those of the first embodiment, and the same reference numerals are used to designate the same configurations as those of the first embodiment, and the description thereof will be omitted.

[0090] In the fifth embodiment, the battery characteristic acquisition unit 63 acquires the discharge voltage characteristic in a predetermined voltage section Vs shown in FIG. 3, as in the first embodiment. Then, the impedance characteristic acquisition unit 67 acquires the discharge end time T P1 , T P2Complex impedance measurement is performed at to obtain impedance at a specified frequency, and real and imaginary axis values ​​are calculated on a complex plane.

[0091] Here, the impedance characteristics can be the real and imaginary axis values ​​of the impedance at a specified frequency f1, and 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 specified frequency f1 can also be used. Also, the difference between the real and imaginary axis values ​​at a specified frequency f1 and a specified 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.

[0092] The correspondence relationship between the impedance characteristics and the total capacity is stored in advance in the correspondence relationship storage unit 51. The correspondence relationship can be created by machine learning using the measurement secondary battery 2, created based on actual measured values ​​obtained by performing an accelerated degradation test using the measurement secondary battery, or created by a calculation formula that logically derives the correspondence relationship between the impedance characteristics and the total capacity at a predetermined voltage using a model of the secondary battery.

[0093] In the fifth embodiment, similarly to the first embodiment, after the possibility determination unit 62 determines whether or not the deterioration degree can be determined, a capacity estimation unit 64 shown in Fig. 17 estimates the total capacity of the secondary battery 2 based on the discharge voltage characteristic acquired by the battery characteristic acquisition unit 63 and the impedance characteristic acquired by the impedance characteristic acquisition unit 67. The deterioration degree determination unit 65 determines the deterioration degree of the secondary battery 2 based on the estimation result of the capacity estimation unit 64, similarly to the first embodiment. According to the fifth embodiment, the total capacity is estimated based on the discharge voltage characteristic and the impedance characteristic, so that the determination accuracy can be further improved.

[0094] In the fifth embodiment, the impedance characteristic acquisition unit 67 measures the complex impedance at the end of discharge T P1 , T P2However, the present invention is not limited to this, and may be performed at other timings. For example, when the battery characteristics acquisition unit 63 acquires the charging voltage characteristics as in the third embodiment, the charging end time T Q1 , T Q2 The impedance characteristic acquisition unit 67 may perform complex impedance measurement. The capacity estimation unit 64 may use an impedance characteristic relation value calculated based on the impedance characteristic instead of the impedance characteristic. 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.

[0095] According to the deterioration level determination device 1 of the fifth embodiment, it is possible to provide a battery pack including a plurality of secondary batteries having a usage history, in which the difference in the deterioration levels of the plurality of secondary batteries determined based on a total capacity estimated using battery characteristics and impedance characteristics related to the impedance when the secondary batteries are discharged or charged is within a predetermined range. In such a battery pack, the variation in the deterioration levels of the secondary batteries included in the battery pack is smaller, so that it is possible to extend the life and improve the quality of the battery pack as a rebuilt product.

[0096] In the fifth embodiment, the deterioration degree determination unit 65 may determine the deterioration degree of the secondary batteries 21-26 based on the battery characteristics and impedance characteristics acquired by the battery characteristics acquisition unit 63, without estimating the total capacity. The battery characteristics acquisition unit 63 may acquire the absolute value of the acquired value as the battery characteristic, and the deterioration degree determination unit 65 may determine the deterioration degree based on the absolute value. The deterioration degree determination unit 65 may determine the deterioration degree of the secondary batteries 21-26 based on the difference between the battery characteristics acquired by the battery characteristics acquisition unit 63. The secondary batteries 21-26 may be classified and assembled into the battery pack 20 so that the deterioration degree of the secondary batteries 21-26 and the difference in the deterioration degree are within a predetermined range.

[0097] (Embodiment 6) In the sixth 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. 18. The initial voltage acquisition unit 68 acquires initial voltages VI1 and VI2, which are open circuit voltages of the secondary battery 2 at the start of discharge T0, as shown in Fig. 19. The correspondence relationship storage unit 51 stores in advance the correspondence relationship between the initial voltage value, the battery characteristics, and the total capacity. The correspondence relationship can be created in the same way as in the first embodiment. The other configurations are the same as those of the first embodiment, and the same reference numerals are used to designate the same configurations as those of the first embodiment, and the description thereof will be omitted.

[0098] According to the deterioration level determination device 1 of the sixth embodiment, the deterioration level of the secondary battery 2 is determined by taking into consideration the initial voltage in addition to the battery characteristics, and therefore the determination accuracy can be further improved with a simple configuration. Note that an initial voltage relation value calculated based on the initial voltage may be used instead of the initial voltage. For example, the initial voltage relation value may be the absolute value of the initial voltage or the difference of the initial voltage acquired by the initial voltage acquisition unit 68.

[0099] The deterioration level determination device 1 of the sixth embodiment can provide an assembled battery 20 including a plurality of secondary batteries 21-26 including reused batteries, in which the difference in the deterioration levels of the plurality of secondary batteries 21-26 is within a predetermined range, the difference being determined based on a total capacity estimated using the initial voltage, which is the open circuit voltage of the secondary batteries 21-26 when acquisition of the battery characteristics is started, and the battery characteristics. In this assembled battery 20, the variation in the deterioration levels of the secondary batteries 21-26 included in the assembled battery 20 is smaller, so that the assembled battery 20 can be made to have a longer life and have improved quality as a rebuilt product.

[0100] In the sixth embodiment, similarly to the modified embodiment of the first embodiment, the deterioration degree determination unit 65 may determine the deterioration degree of the secondary batteries 21-26 based on the battery characteristics and initial voltage acquired by the battery characteristics acquisition unit 63 without estimating the total capacity. The battery characteristics acquisition unit 63 may acquire the absolute value of the acquired value as the battery characteristics, and the deterioration degree determination unit 65 may determine the deterioration degree based on the absolute value. The deterioration degree determination unit 65 may determine the deterioration degree of the secondary batteries 21-26 based on the difference between the battery characteristics acquired by the battery characteristics acquisition unit 63. The secondary batteries 21-26 may be classified and assembled into the battery pack 20 so that the deterioration degree of the secondary batteries 21-26 and the difference in the deterioration degree are within a predetermined range.

[0101] As another modified embodiment 7, as shown in FIG. 20, the calculation unit 6 may have an internal resistance acquisition unit 69 for acquiring the internal resistance of the secondary batteries 21-26, and the correspondence between the internal resistance, the battery characteristics, and the total capacity may be stored in advance in the correspondence storage unit 51. In the internal resistance acquisition unit 69, the internal resistance may be acquired by calculating the measured voltage, which is the voltage value detected by the voltage value detection unit 31, the open voltage of the secondary batteries 21-26, and the current flowing through the secondary batteries 21-26. The open voltage of the secondary battery 2 may be estimated and acquired every hour using a map showing the correspondence between the remaining discharge amount and the initial voltage of the secondary batteries 21-26. According to the deterioration degree determination device 1 of the modified embodiment 7, the deterioration degree of the secondary batteries 21-26 is determined taking into account the internal resistance in addition to the battery characteristics, so that the determination accuracy can be further improved with a simple configuration.

[0102] (Embodiment 7) The deterioration level determination device 1 of the seventh embodiment includes a temperature detection unit 33 as shown in FIG. 21 in addition to the configuration of the first embodiment shown in FIG. 1. In the first embodiment described above, the battery characteristic acquisition unit 63 is configured to acquire the discharge voltage characteristic based on the voltage transition of the secondary battery 2 in a predetermined voltage section Vs as the battery characteristic. Instead, in the seventh embodiment, the battery characteristic acquisition unit 63 acquires the temperature characteristic based on the temperature transition of the secondary battery 2 in the predetermined voltage sections VsA and VsB as the battery characteristic. The other configurations are the same as those of the first embodiment, and the same reference numerals are used to designate the same configurations as those of the first embodiment, and the description thereof will be omitted. The voltage section VsA is a section in which the difference in the discharge voltage characteristic is significant depending on the deterioration level of the secondary battery 2, and the voltage section VsB is a section in which the difference in the charge voltage characteristic is significant depending on the deterioration level of the secondary battery 2.

[0103] In the seventh embodiment, as shown in Fig. 22(a) and Fig. 22(b), the temperature of the secondary battery 2 during charging and discharging is obtained by the temperature detection unit 33. In the seventh 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 the secondary batteries 2 determined to be capable of being determined for their degree of deterioration.

[0104] 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 seventh embodiment, as shown in FIG. 22(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 seventh embodiment, after the possibility determination unit 62 determines that the deterioration degree can be determined, the battery characteristic acquisition unit 63 acquires the temperature characteristic during discharging and the temperature characteristic during charging based on the battery temperature 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. Then, the capacity estimation unit 64 estimates the total capacity of each of the secondary batteries 21 and 27 based on both temperature characteristics, and the deterioration degree determination unit 65 determines the deterioration degree.

[0105] The temperature characteristics acquired by the battery characteristics acquisition unit 63, similar to when calculating the discharge voltage characteristics in embodiment 1 and when calculating the charge voltage characteristics in embodiment 3, can be the differential value of the temperature change at specified voltages VA, VB in the specified voltage ranges VsA, VsB, the ratio of the temperature change between two points in the specified voltage ranges VsA, VsB, or the ratio of the temperature change of the secondary battery 2 to the capacity change of the secondary battery 2 in the voltage ranges VsA, VsB.

[0106] In the present embodiment 7, the same action and effect as in the embodiment 1 can be achieved. Note that, in the present embodiment 7, the temperature characteristic is obtained in both discharging and charging, but this is not limited thereto, and it may be obtained in only one of discharging and charging.

[0107] According to the deterioration level determination device 1 of the seventh embodiment, it is possible to provide a battery pack including secondary batteries having a usage history, in which the difference in the deterioration levels of the multiple secondary batteries determined based on the total capacity estimated using battery characteristics including temperature characteristics based on the temperature transition 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 deterioration levels of the secondary batteries included in the battery pack is smaller, and therefore the quality of the battery pack as a rebuilt product can be improved.

[0108] In the seventh embodiment, the deterioration degree determination unit 65 may determine the deterioration degree of the secondary batteries 21-26 based on the temperature characteristics acquired by the battery characteristics acquisition unit 63 without estimating the total capacity. The battery characteristics acquisition unit 63 may acquire the absolute value of the acquired value as the temperature characteristics, and the deterioration degree determination unit 65 may determine the deterioration degree based on the absolute value. The deterioration degree determination unit 65 may determine the deterioration degree of the secondary batteries 21-26 based on the difference in the temperature characteristics acquired by the battery characteristics acquisition unit 63. The secondary batteries 21-26 may be classified and assembled into the battery pack 20 so that the deterioration degrees of the secondary batteries 21-26 and the difference in the deterioration degrees are within a predetermined range.

[0109] In the seventh embodiment, as shown in FIG. 22(a), the temperature characteristic during charging is obtained when the charging target voltage VQ is within the normal use range Vn and the predetermined voltage section VsA is within the normal use range Vn. Alternatively, as shown in the eighth modified embodiment in FIG. 23(a), the temperature characteristic during charging may be obtained when the charging target voltage VQ exceeds the normal use range Vn and the predetermined voltage section VsB is within the region beyond the normal use range Vn. In this case, as shown in FIG. 23(b), the temperature of the secondary batteries 21 and 27 is likely to rise, so that the deterioration degree is easily reflected in the temperature transition. As a result, the accuracy of the determination can be improved. In the eighth modified embodiment, the secondary batteries 21 and 27 are charged to the charging target voltage VQ and then discharged to return the voltage of the secondary batteries 21 and 27 to the normal use range Vn.

[0110] In addition, in the eighth modified embodiment, the secondary battery 2 is discharged, then charged, and then discharged again. Alternatively, as in the ninth modified embodiment shown in Fig. 24(a) and Fig. 24(b), the secondary battery 2 may be charged and then discharged without first discharging. 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. In this case, the same effects as those of the first embodiment can be achieved.

[0111] (Embodiment 8) In the above-mentioned 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, but 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 between the multiple cells constituting the secondary batteries 21-26, and the battery resistance, the positive electrode resistance, and the negative electrode resistance of the secondary batteries 21-26. In the embodiment 8, the capacity estimation unit 64 estimates the positive electrode capacity Qc of each of the secondary batteries 21-26. Furthermore, the correspondence storage unit 51 stores the correspondence between the battery characteristics and the positive electrode capacity Qc. The form and the method of creating the correspondence are not particularly limited, and may be in the form of, for example, a calculation formula, a map, a graph, a table, etc., as in the case of embodiment 1. The correspondence relationship can be created by machine learning using the secondary battery 2 for measurement, based on actual measured values ​​obtained by performing an accelerated deterioration test using the secondary battery 2 for measurement, 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 this 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 model shown in Figures 25(a) to (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 the description thereof will be omitted.

[0112] Next, a method for determining the degree of deterioration by the deterioration degree determining device 1 of the eighth embodiment will be described below. Note that the same steps as those in the first embodiment shown in FIG. 5 will be designated by the same reference numerals and the description thereof will be omitted in some cases. First, in the eighth embodiment, steps S1 to S5 shown in Fig. 26 are performed in the same manner as in the first embodiment shown in Fig. 5. As a result, as shown in Fig. 27(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 section Vs. Note that the predetermined voltage section can be a section corresponding to a particular SOC range.

[0113] Next, in step S74 shown in FIG. 26, the capacity estimation unit 64 estimates the positive electrode capacity Qc of the secondary batteries 21-26 from the discharge curve acquired by the battery characteristic acquisition unit 63 based on the correspondence between the battery characteristics and the positive electrode capacity Qc based on the prediction model stored in the correspondence storage unit 51. Thereafter, in step S8 shown in FIG. 26, the deterioration degree determination unit 65 determines the deterioration degree of the secondary batteries 21-26 based on the positive electrode capacity Qc estimated by the capacity estimation unit 64. Also, as in the case of the first embodiment shown in FIG. 5, after steps S9 and S10 shown in FIG. 26 are performed, in step S110, the charge and discharge control unit 71 performs charging and discharging for the secondary batteries whose deterioration degree is not determined, and measures the actual value of the positive electrode capacity. Then, in step S12, as in the case of the first embodiment, the possibility determination criterion and the deterioration degree determination criterion are updated.

[0114] In the present embodiment 8, the same effects as those of the embodiment 1 are achieved. In the present embodiment 8, the discharge curve shown in Fig. 27(a) is acquired by the battery characteristics acquisition unit 63, but instead of this, the charge curve shown in Fig. 27(b) may be acquired. In this case, the same effects as those of the embodiment 1 are achieved.

[0115] (Embodiment 9) In the above-mentioned embodiment 8, the capacity estimation unit 64 estimates the positive electrode capacity Qc, but instead, in embodiment 9, the capacity estimation unit 64 estimates the negative electrode capacity QA. That is, in embodiment 9, as shown in Fig. 28, in steps S75 and S111, the negative electrode capacity QA of the secondary batteries 21-26 is estimated based on the correspondence between the battery characteristics and the negative electrode capacity QA, based on the prediction model shown in Figs. 25(a)-(c). In embodiment 9, the same effects as those in embodiment 1 are achieved.

[0116] (Embodiment 10) In the tenth embodiment, the 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, the correspondence storage unit 51 stores the correspondence between the battery characteristics and the amount of deviation in the relative relationship between the negative electrode SOC and the positive electrode SOC. The form and creation method of the correspondence are not particularly limited and may be the same as in the first embodiment.

[0117] For example, when the secondary batteries 21-26 are nickel-metal hydride batteries, the relative relationship between the negative electrode SOC and the positive electrode SOC changes when hydrogen escapes from the reaction system in the battery container, and the negative electrode OCV curve shifts to the right in the figure, as shown in Fig. 29. For example, when the secondary batteries 21-26 are lithium-ion batteries, the relative relationship between the negative electrode SOC and the positive electrode SOC changes when lithium in the electrolyte is consumed in the formation of an SEI (Solid Electrolyte Interface) film, and the negative electrode OCV curve shifts to the right in the figure, as shown in Fig. 29.

[0118] In the tenth 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 a correspondence storage unit 51 based on the prediction model shown in Fig. 29. 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 the description thereof will be omitted.

[0119] The deterioration level determination method by the deterioration level determination device 1 of the present embodiment 10 is performed in the same manner as in the above-mentioned embodiment 8, but in step S3 as shown in FIG. 30, the battery characteristic acquisition unit 63 acquires a discharge curve of a predetermined voltage section Vs corresponding to a low SOC range as a battery as a battery characteristic. Thereafter, steps S4 to S5 shown in FIG. 30 are performed in the same manner as in the embodiment 1 shown in FIG. 5. Then, the process proceeds to step S76, and the deviation amount Qx of the secondary batteries 21 to 26 is estimated based on the correspondence relationship between the battery characteristic 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 relationship storage unit 51. Thereafter, in step S5 shown in FIG. 30, the deterioration level determination unit 65 determines the deterioration level of the secondary batteries 21 to 26 based on the deviation amount Qx estimated by the capacity estimation unit 64. The present embodiment 10 also has the same effect as the embodiment 1. In the present embodiment 10, the battery characteristics are acquired from the low SOC range as a battery, but instead, they may be acquired from the high SOC range. In addition, in the tenth embodiment, a discharge curve is obtained as the battery characteristics, but a charge curve may also be obtained.

[0120] (Embodiment 11) In this embodiment 11, 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 21-26, the capacity estimation unit 64 estimates the amount of change in discharge capacity on the charge / discharge curve in a predetermined voltage section Vs, and the deterioration degree determination unit 65 detects whether the amount of self-discharge of the cell is increasing based on the estimation result as the deterioration degree. In this embodiment 11, the other configurations are the same as in the case of embodiment 1, and the same reference numerals as in embodiment 1 are used and the description thereof is omitted.

[0121] In this embodiment 11, each of the secondary batteries 21 to 26 has six cells. For example, the discharge curve shown in FIG. 31(a) is stored in the correspondence storage unit 51 as a discharge curve showing an initial state, and the discharge curve shown in FIG. 31(b) is stored in the correspondence storage unit 51 as a discharge curve showing that one of the cells has a large self-discharge amount. When the capacity estimation unit 64 estimates the discharge curve shown in FIG. 31(a) based on the battery characteristics in a predetermined voltage section Vs, the deterioration degree determination unit 65 determines that there is no cell with a large self-discharge amount. On the other hand, when the capacity estimation unit 64 estimates the discharge curve shown in FIG. 31(b) based on the battery characteristics in a predetermined voltage section Vs, the deterioration degree determination unit 65 determines that there is one cell with a large self-discharge amount. Note that when the discharge curve shown in FIG. 31(b) is estimated, the lower limit of use can be set to a second lower limit of use Vmin2 that is a value higher than the first lower limit of use Vmin1 when there is no cell with a large self-discharge amount in the secondary battery. This makes it possible to prevent each cell from being excessively discharged.

[0122] (Embodiment 12) In the present embodiment 12, each of the secondary batteries 21-26 includes six cells. The correspondence storage unit 51 stores the correspondence between the total capacity variation between the cells in one of the secondary batteries 21-26 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 21-26. In the present embodiment 12, as shown in FIG. 32, the difference Qmax-min obtained by subtracting the minimum Qmin from the maximum Qmax in the total capacity of the multiple cells is used as the total capacity variation between the cells. 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 the description thereof will be omitted.

[0123] In the twelfth 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, when 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 any of the cells of the secondary batteries 21 to 26.

[0124] (Embodiment 13) As shown in FIG. 33, in the thirteenth embodiment, the estimation unit has a resistance estimation unit 641. The resistance estimation unit 641 estimates the internal resistance of the secondary batteries 21-26 based on the battery characteristics of the secondary batteries 21-26. The correspondence storage unit 51 stores the correspondence between the internal resistance and the battery characteristics of each of the secondary batteries 21-26. The battery characteristics acquisition unit 63 can acquire the battery characteristics by performing pulse charging and discharging while the secondary batteries 21-26 are connected to each other in a stacked state. The voltage section for acquiring the battery characteristics can be a predetermined voltage section corresponding to a specific SOC range.

[0125] Furthermore, when the temperature or SOC differs between the secondary batteries 21-26, the temperature and the voltage change during charging / discharging or the voltage change during voltage relaxation after charging / discharging are acquired as battery characteristics, and the resistance value when the temperature and SOC are the same can be estimated. In this case, the correspondence storage unit 51 stores the correspondence between the internal resistance, temperature, and battery characteristics of each of the secondary batteries 21-26. The secondary batteries 21-26 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.

[0126] Next, a method of determining the degree of deterioration by the deterioration degree determination device 1 of the present embodiment 13 will be described below. First, in the present embodiment 13, steps S1 to S5 shown in FIG. 34 are performed in the same manner as in the case of the embodiment 1 shown in FIG. 5. Next, in step S77 shown in FIG. 34, the resistance estimation unit 641 acquires the internal resistance of the secondary batteries 21 to 26 based on the correspondence between the internal resistance and the battery characteristics of the secondary batteries 21 to 26 stored in the correspondence storage unit 51 from the battery characteristics acquired by the battery characteristics acquisition unit 63. Thereafter, in step S8 shown in FIG. 34, the deterioration degree determination unit 65 determines the deterioration degree of the secondary batteries 21 to 26 based on the internal resistance estimated by the resistance estimation unit 641. Also, in the same manner as in the case of the embodiment 1 shown in FIG. 5, after performing steps S9 and S10 shown in FIG. 34, in step S113, the charge and discharge control unit 71 performs charging and discharging for the secondary batteries whose deterioration degree is not determined, and measures the actual value of the internal resistance. Then, in step S12, the possibility determination criterion and the deterioration degree determination criterion are updated in the same manner as in the case of the embodiment 1. The thirteenth embodiment also provides the same advantageous effects as the first embodiment.

[0127] (Embodiment 14) In the deterioration level determining device 1 of the fourteenth embodiment, the resistance estimation unit 641 estimates the negative electrode resistance of the secondary batteries 21-26, and the deterioration level determining unit 65 determines the deterioration levels of the secondary batteries 21-26.

[0128] From the frequency characteristics in the voltage curves of the secondary batteries 21-26, the resistance values ​​of the positive and negative electrodes and other battery elements in the secondary batteries 21-26 can be calculated. In nickel-metal hydride batteries and lithium-ion batteries, the negative electrode resistance is prominently reflected in the high frequency region of the voltage curve, and the positive electrode resistance is prominently reflected in the low frequency region. In the present embodiment 14, nickel-metal hydride batteries are used as the secondary batteries 21-26, and the battery characteristic acquisition unit 63 acquires a voltage curve in a predetermined voltage section in the high frequency region as the battery characteristics. The correspondence relationship storage unit 51 stores in advance the correspondence relationship between the voltage curve in the high frequency region and the negative electrode resistance as the battery characteristics. The other components are the same as those in the embodiment 13, and the same reference numerals are used and the description thereof is omitted.

[0129] In the internal resistance having a correlation with the deterioration degree of the secondary batteries 21 to 26, the resistance element that is dominant differs depending on the deterioration mode. First, the internal resistance of the secondary battery module is determined by the relationship between three resistance components, namely, electronic resistance, reaction resistance, and internal mass transfer resistance, and the secondary battery module can be considered as a series equivalent circuit of these three resistance components. In general, electronic resistance is a resistance component that occurs mainly in the time domain immediately after a constant current is applied to the battery. Moreover, reaction resistance is a resistance component that occurs mainly in the time domain after the time domain in which electronic resistance occurs. Moreover, internal mass transfer resistance is a resistance component that occurs when a constant current is applied for a long time, and occurs mainly in the time domain after the time domain in which reaction resistance occurs. And, the negative electrode reaction resistance dominating region is a time domain in which the proportion of the reaction resistance of the negative electrode during the discharge period is the largest among the above three resistance components. In the negative electrode reaction resistance dominating region, the reaction resistance of the negative electrode dominantly determines the internal resistance of the secondary battery 2. In the fourteenth 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.

[0130] In the method of determining the degree of deterioration by the deterioration degree determination device 1 of the present embodiment 14, steps S1 to S5 shown in FIG. 34 are performed in the same manner as in the case of the embodiment 13. Then, in step S77, the resistance estimation unit 641 estimates the negative electrode resistance of the secondary batteries 21 to 26 based on the voltage curve acquired by the battery characteristic acquisition unit 63 and the correspondence stored in the correspondence storage unit 51. Then, the deterioration degree determination unit 65 determines the degree of deterioration of the secondary batteries 21 to 26 from the estimated negative electrode resistance. Also, in the same manner as in the case of the embodiment 1 shown in FIG. 5, after performing steps S9 and S10 shown in FIG. 34, in step S113, the charge / discharge control unit 71 performs charging / discharging for the secondary batteries whose deterioration degree is not determined, and measures the actual value of the negative electrode resistance. Then, in step S12, the possibility determination criterion and the deterioration degree determination criterion are updated in the same manner as in the case of the embodiment 1. The present embodiment 14 also has the same effects as the embodiment 1.

[0131] (Embodiment 15) In the deterioration level determination device 1 of the fifteenth embodiment, the resistance estimation unit 641 estimates the positive electrode resistance of the secondary batteries 21-26, and the deterioration level determination unit 65 determines the deterioration level of the secondary batteries 21-26. In the fifteenth embodiment, nickel-metal hydride batteries are used as the secondary batteries 21-26, and the battery characteristic acquisition unit 63 acquires a voltage curve in a predetermined voltage section in a low frequency region as the battery characteristic. The correspondence relationship storage unit 51 prestores a correspondence relationship between the voltage curve and the positive electrode resistance as the battery characteristic. Then, the deterioration level determination unit 65 determines the deterioration level of the secondary batteries 21-26 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 fourteenth embodiment, and the same reference numerals are used to omit the description thereof.

[0132] In the deterioration degree determination method by the deterioration degree determination device 1 of the present embodiment 15, steps S1 to S5 shown in FIG. 34 are performed in the same manner as in the case of the embodiment 14. Then, in step S77, the resistance estimation unit 641 estimates the positive electrode resistance of the secondary batteries 21 to 26 based on the voltage curve acquired by the battery characteristic acquisition unit 63 and the correspondence stored in the correspondence storage unit 51. Then, the deterioration degree determination unit 65 determines the deterioration degree of the secondary batteries 21 to 26 from the estimated positive electrode resistance. Also, in the same manner as in the case of the embodiment 1 shown in FIG. 5, after performing steps S9 and S10 shown in FIG. 34, in step S113, the charge / discharge control unit 71 performs charging / discharging for the secondary batteries whose deterioration degree is not determined, and measures the actual measured value of the positive electrode resistance. Then, in step S12, the possibility determination criterion and the deterioration degree determination criterion are updated in the same manner as in the case of the embodiment 1. The present embodiment 15 also has the same effects as the embodiment 1.

[0133] The present invention is not limited to the above-described embodiments, and can be applied to various embodiments without departing from the gist of the present invention. [Explanation of symbols]

[0134] 1 Deterioration degree determination device 2, 21~27 Secondary battery 20 Battery pack 33 Temperature detection section 61 Battery information acquisition section 62 Possibility judgment part 63 Battery characteristic acquisition unit 64 Capacity estimation part 65 Deterioration degree determination section 66 Vehicle Information Acquisition Unit 67 Impedance characteristic acquisition section 68 Initial voltage acquisition unit 69 Internal resistance acquisition section

Claims

1. A deterioration degree determination device (1) for determining a deterioration degree of a secondary battery (21 to 26), comprising: a battery information acquisition unit (61) for acquiring battery information relating to the secondary battery; a determination unit (62) for determining whether or not a deterioration level of each of the secondary batteries can be determined based on the battery information acquired by the battery information acquisition unit and a previously prepared determination criterion; a battery characteristic acquisition unit (63) for acquiring battery characteristics relating to a transition of a battery state in a predetermined voltage range for the secondary battery for which the deterioration degree determination is determined to be possible by the possibility determination unit; a deterioration level determination unit (65) for determining a deterioration level of the secondary battery for which it has been determined that the deterioration level can be determined based on the battery characteristics acquired by the battery characteristics acquisition unit or a battery characteristic related value calculated based on the battery characteristics; Equipped with the battery characteristics include a discharge voltage characteristic based on at least one of a voltage transition when the secondary battery is discharged to a predetermined discharge target voltage and a voltage transition after the secondary battery is discharged to the discharge target voltage and discharging is stopped, the voltage transition is calculated based on at least one of a section capacity of the secondary battery in the voltage section, a ratio of a voltage change of the secondary battery to a capacity change of the secondary battery in the voltage section, a ratio of a voltage change of the secondary battery to an elapsed time in the voltage section, and a capacity ratio of the section capacity of the voltage section to a total discharge capacity when discharged to the discharge target voltage; The device for determining the deterioration degree of a secondary battery, wherein the feasibility determination unit uses a data distance calculated based on two or more pieces of battery information acquired in advance as the feasibility determination criterion, and uses a relational equation related to a plurality of pieces of battery information set in advance to make the feasibility determination based on a comparison result between a battery information relation value calculated from the battery information acquired by the battery information acquisition unit and the feasibility determination criterion.

2. A secondary battery deterioration determination device as described in claim 1, wherein the voltage trend is calculated based on at least two of the following: the section capacity of the secondary battery in the voltage range, the ratio of the voltage change of the secondary battery to the capacity change of the secondary battery in the voltage range, the ratio of the voltage change of the secondary battery to the elapsed time in the voltage range, and the capacity ratio of the section capacity of the voltage range to the total discharge capacity when discharged to the target discharge voltage.

3. A deterioration degree determination device (1) for determining a deterioration degree of a secondary battery (21 to 26), comprising: a battery information acquisition unit (61) for acquiring battery information relating to the secondary battery; a determination unit (62) for determining whether or not a deterioration level of each of the secondary batteries can be determined based on the battery information acquired by the battery information acquisition unit and a previously prepared determination criterion; a battery characteristic acquisition unit (63) for acquiring battery characteristics relating to a transition of a battery state in a predetermined voltage range for the secondary battery for which the deterioration degree determination is determined to be possible by the possibility determination unit; a deterioration level determination unit (65) for determining a deterioration level of the secondary battery for which it has been determined that the deterioration level can be determined based on the battery characteristics acquired by the battery characteristics acquisition unit or a battery characteristic related value calculated based on the battery characteristics; Equipped with the battery characteristics include a charging voltage characteristic based on at least one of a voltage transition when the secondary battery is charged to a predetermined charging target voltage and a voltage transition after the secondary battery is charged to the charging target voltage and charging is stopped, the voltage transition is calculated based on at least one of a section capacity of the secondary battery in the voltage section, a ratio of a voltage change of the secondary battery to a capacity change of the secondary battery in the voltage section, a ratio of a voltage change of the secondary battery to an elapsed time in the voltage section, and a capacity ratio of the section capacity of the voltage section to a total charge capacity when the secondary battery is charged to the charge target voltage, The device for determining the deterioration degree of a secondary battery, wherein the feasibility determination unit uses a data distance calculated based on two or more pieces of battery information acquired in advance as the feasibility determination criterion, and uses a relational equation related to a plurality of pieces of battery information set in advance to make the feasibility determination based on a comparison result between a battery information relation value calculated from the battery information acquired by the battery information acquisition unit and the feasibility determination criterion.

4. A secondary battery deterioration determination device as described in claim 3, wherein the voltage trend is calculated based on at least two of the following: the section capacity of the secondary battery in the voltage range, the ratio of the voltage change of the secondary battery to the capacity change of the secondary battery in the voltage range, the ratio of the voltage change of the secondary battery to the elapsed time in the voltage range, and the capacity ratio of the section capacity of the voltage range to the total charging capacity when charged to the target charging voltage.

5. A deterioration degree determination device for a secondary battery as described in any one of claims 1 to 4, wherein the battery information includes at least one of the battery characteristics and historical information of the secondary battery.

6. A deterioration degree determination device for a secondary battery as described in any one of claims 1 to 4, wherein the battery information includes both the battery characteristics and historical information on the secondary battery.

Images