Battery diagnosis device and program

Abstract

To suitably calculate SOH for each unit cell included in an assembled battery.SOLUTION: A battery system 10 comprises: an assembled battery 20 that includes a plurality of unit cells 21 connected in series; and sensors 25 and 26 that are provided on at least one of the unit cells 21 and detect a parameter for deterioration diagnosis. A BMU 30 includes: a first calculation section that acquires the parameter detected by the detection section for the unit cell 21 and calculates SOH on the basis of the parameter; a second calculation section that calculates an amount of change in the SOC caused by energization for the plurality of unit cells 21; and a third calculation section that calculates, when the unit cell 21 for which the first calculation section has calculated the SOH is a first unit cell 21A and the unit cell 21 for which the SOH has not been calculated is a second unit cell 21A, a value obtained by multiplying a change amount ratio, which is a ratio of an amount of change in the SOC of the first unit cell 21A to an amount of change in the SOC of a second unit cell 21B, by the SOH of the first unit cell 21A, as the SOH of the second unit cell 21B.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery diagnostic device and a program. [Background technology]

[0002] In a storage battery, the full charge capacity decreases as the battery deteriorates. Therefore, a technique for calculating the SOH (State Of Health) as a deterioration index showing the deterioration degree of the storage battery is known. A technique has been disclosed in which a secondary battery is provided with a temperature sensor for detecting the battery temperature and a sensor for detecting the impedance (internal resistance) of the secondary battery, and the capacity of the secondary battery is estimated based on the battery temperature and impedance (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-34383 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a battery pack having multiple cells, the temperature and impedance of each cell must be detected in order to calculate the SOH of each cell. However, if sensors for detecting the temperature and impedance are provided for all cells, there are concerns about increased costs and larger size.

[0005] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a battery diagnosis device and a program that can suitably calculate the SOH of each battery cell included in a battery pack. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides: A battery diagnosis device that is applied to a battery system including a battery pack formed by connecting a plurality of unit cells in series, and a detection unit that is provided in at least one of the plurality of unit cells and detects a parameter for deterioration diagnosis, and calculates a state of health (SOH) that indicates a degree of deterioration of each of the unit cells, a first calculation unit that acquires the parameter detected by the detection unit for at least one of the plurality of unit cells and calculates the SOH based on the parameter; A second calculation unit that calculates a change in SOC caused by energization of the plurality of single cells; a third calculation unit that calculates, when a cell of the plurality of cells for which the SOH has been calculated by the first calculation unit is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell, a value obtained by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, by the SOH of the first cell, as the SOH of the second cell; The present invention is characterized by comprising:

[0007] In a battery pack, the remaining capacity change of each cell caused by energization corresponds to the product of the change in SOH and SOC (State Of Charge) of the cell and the reference full charge capacity. In this case, in a battery pack in which a plurality of cells are connected in series, the remaining capacity change of each cell is the same even if the SOH of each cell is different, so the product of the SOH and the SOC change of each cell is the same. In view of this, among the plurality of cells, a cell whose SOH has been calculated based on a parameter for deterioration diagnosis is defined as a first cell, and a cell whose SOH has not been calculated is defined as a second cell. Then, the SOH of the second cell is calculated by multiplying the change ratio, which is the ratio of the SOC change of the first cell to the SOC change of the second cell, by the SOH of the first cell. This makes it possible to calculate the SOH of all the cells even if the parameters for deterioration diagnosis have not been acquired for all the cells. As a result, the SOH can be suitably calculated for each cell included in the battery pack. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a configuration of a battery system. [Diagram 2] FIG. 13 shows a correlation map used to calculate SOH. [Diagram 3] FIG. 2 is a graph showing the voltage-SOC characteristics of a single battery. [Figure 4] 4 is a flowchart showing a procedure for calculating the SOH of a single cell. [Diagram 5] FIG. 13 is a diagram showing the configuration of a modified example of the battery system. [Figure 6] FIG. 13 is a diagram showing the configuration of a modified example of the battery system. [Figure 7] FIG. 13 is a diagram showing the configuration of a battery system according to a second embodiment. [Figure 8] 10 is a flowchart showing a SOH calculation process in the second embodiment. [Figure 9] 13 is a flowchart showing a SOH calculation process in the third embodiment. [Figure 10] FIG. 2 is a diagram showing a voltage-SOC characteristic line of a single battery. [Figure 11] FIG. 13 is a diagram showing the configuration of a battery system according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (First embodiment) A first embodiment will be described below with reference to the drawings. In this embodiment, a battery system 10 mounted on an electrically powered vehicle such as a hybrid vehicle or an electric vehicle will be described. FIG. 1 is a diagram showing the configuration of the battery system 10.

[0010] In FIG. 1, the battery system 10 includes a battery pack 20 and a BMU 30 (Battery Management Unit) as a monitoring device for monitoring the battery pack 20. The battery pack 20 is configured by connecting a plurality of single cells 21 in series. The single cells 21 are, for example, lithium ion batteries. The single cells 21 may be configured by a plurality of battery cells, and for example, the plurality of battery cells may be connected in series or in parallel. The battery pack 20 includes n single cells 21, and in FIG. 1, the single cells 21 are numbered 1, 2, . . . , n-2, n-1, n in order from the negative electrode side of the battery pack 20. All the single cells 21 have the same configuration, and the rated capacity of each single cell 21 is the same.

[0011] A current sensor 23 is provided on the electrical path 22 in which each of the cells 21 is connected in series. The battery pack 20 is also provided with a voltage sensor 24 that detects the voltage across each of the cells 21. The voltage sensor 24 monitors the terminal voltages of all of the cells 21.

[0012] Of the n cells 21, a specific cell 21 is provided with a temperature sensor 25 for detecting the battery temperature and an impedance sensor 26 for detecting the impedance as an internal resistance. Any impedance detection method may be used in the impedance sensor 26, but it is preferable that the impedance is calculated from a voltage response when an alternating current is applied to the cell 21. The impedance may be calculated at a plurality of frequencies.

[0013] In the following description, in order to distinguish between a cell 21 provided with a temperature sensor 25 and an impedance sensor 26 (cell 21 with sensor) and a cell 21 not provided with these sensors 25, 26 (cell 21 without sensor), the cell 21 with sensor will be referred to as the "first cell 21A" and the cell 21 without sensor will be referred to as the "second cell 21B." In the drawings, to avoid complication, of the cell 21's reference characters 21A and 21B, only the reference character 21A is given, and among the multiple cells 21, the cell 21 not given the reference character 21A corresponds to the second cell 21B.

[0014] In this embodiment, among the n cells 21, the cell 21 that becomes the hottest when the battery pack 20 is energized (when charging or discharging) is designated as the first cell 21A, and temperature detection is performed by a temperature sensor 25 and impedance detection is performed by an impedance sensor 26 for the first cell 21A.

[0015] Supplementally, when the battery pack 20 is energized, a relative temperature difference occurs among the n cells 21 depending on the arrangement structure in the battery case and the positional relationship with the cooling device. For example, when the cells 21 are arranged side by side, it is considered that the temperature of the cells 21 near the center of the arrangement is relatively high and the temperature of the cells 21 near the ends of the arrangement is relatively low. In this embodiment, among the n cells 21 shown in FIG. 1, the n-2 cell 21 is the cell 21 that becomes the hottest under energized conditions, and the n-2 cell 21 is the first cell 21A, and the cells 21 other than the n-2 cell 21 are the second cell 21B.

[0016] The first cell 21A may be selected from among the cells 21 as a high-temperature battery that becomes relatively hot when the battery pack 20 is in a powered state, for example, as a cell 21 that becomes hotter than the average temperature of all the cells 21.

[0017] The BMU 30 is an electronic control device having a microcomputer with a CPU and various memories, and the detection signals of the various sensors described above are input to the BMU 30 as appropriate. The BMU 30 executes various arithmetic processing related to the battery pack 20 based on a program stored in the memory. Specifically, the BMU 30 calculates the SOC as an index indicating the charge state of each cell 21 based on the terminal voltage of each cell 21. The BMU 30 also calculates the SOH as an index indicating the deterioration state of each cell 21 based on the battery temperature and impedance of each cell 21. The SOH corresponds to a deterioration index indicating the degree of deterioration of each cell 21. In this embodiment, the BMU 30 corresponds to a "battery diagnosis device", and the temperature sensor 25 and the impedance sensor 26 correspond to a "detection unit" that detects parameters for deterioration diagnosis of the cell 21.

[0018] The configuration for calculating the SOH of each cell 21 will be described in detail below.

[0019] In the battery system 10 of the present embodiment, the temperature sensor 25 and the impedance sensor 26 are provided only in a specific cell 21 (first cell 21A) among the multiple cells 21. In other words, it is possible to obtain parameters for deterioration diagnosis only from the first cell 21A, and it is possible to calculate the SOH based on the diagnosis parameters. In other words, it is not possible to calculate the SOH based on the diagnosis parameters (battery temperature, impedance) for the second cell 21B other than the first cell 21A. However, in the assembled battery 20, the remaining capacity change amount of each cell 21 caused by energization corresponds to the product of the SOH and SOC change amount of the cell 21 and the reference full charge capacity. In this case, in the assembled battery 20 in which the multiple cells 21 are connected in series, even if the SOH of each cell 21 is different, the remaining capacity change amount of each cell 21 is the same, so that the product of the SOH and the SOC change amount of each cell 21 is the same. In consideration of this point, in this embodiment, the SOH of the second cell 21B is calculated based on the ratio between the SOH of the first cell 21A and the change in SOC (ΔSOC) of each of the first cell 21A and the second cell 21B.

[0020] That is, the SOC [%] and SOH [%] of each cell 21 are expressed by the following (Equation 1) and (Equation 2). Note that Cr is the remaining capacity [Ah] of the cell 21, Cf is the actual fully charged capacity [Ah] of the cell 21, and Cf0 is the reference fully charged capacity [Ah] of the cell 21. SOC=Cr / Cf…(Formula 1) SOH=Cf / Cf0…(Formula 2) Furthermore, when the remaining capacity Cr of the cell 21 changes with energization, the remaining capacity change amount ΔCr is expressed by the following (Equation 3). ΔCr=ΔSOC×Cf =ΔSOC×(SOH×Cf0)…(Formula 3) In this case, the remaining capacity change amount ΔCr is the same regardless of the SOH of each cell 21, so in comparing the first cell 21A and the second cell 21B, their "ΔSOC×SOH" are the same.

[0021] Here, if the SOH of the first cell 21A is "SOH1" and ΔSOC is "ΔSOC1", and the SOH of the second cell 21B is "SOH2" and ΔSOC is "ΔSOC2", then "ΔSOC1×SOH1=ΔSOC2×SOH2", and the following (Equation 4) holds. SOH2=SOH1×(ΔSOC1 / ΔSOC2) …(Formula 4) In this embodiment, the SOH2 of the second cell 21B is calculated using (Equation 4). In this case, the SOH2 of the second cell 21B is calculated by referring to ΔSOC1 and SOH1 of the first cell 21A. That is, according to (Equation 4), the SOH2 of the second cell 21B is calculated by multiplying the change rate, which is the ratio of the SOC change amount (ΔSOC1) of the first cell 21A to the SOC change amount (ΔSOC2) of the second cell 21B, by the SOH1 of the first cell 21A.

[0022] As shown in FIG. 1, the BMU 30 has a first SOH calculation section 31, an SOC calculation section 32, a ΔSOC calculation section 33, and a second SOH calculation section 34 as components related to SOH calculation.

[0023] The first SOH calculation unit 31 acquires the battery temperature and impedance for the first battery 21A, and calculates the SOH1 of the first battery 21A based on the battery temperature and impedance. In this case, it is preferable to calculate SOH1 using, for example, a correlation map showing the correlation between the battery temperature and impedance and the SOH. An example of the correlation map is shown in FIG. 2. In the correlation map, the SOH value is preferably determined by compatibility or the like. However, instead of the correlation map, it is also possible to calculate SOH1 using a correlation equation that specifies the relationship between the battery temperature and impedance and the SOH.

[0024] The SOC calculation unit 32 acquires the terminal voltage of each of all the cells 21, and calculates the SOC based on the terminal voltage. In this case, the SOC calculation unit 32 may calculate the SOC of each cell 21 using the voltage-SOC characteristics shown in FIG. 3. The voltage acquired as the terminal voltage may be the OCV (Open Circuit Voltage) when the cell 21 is not energized. The OCV may be the voltage after the energization of each cell 21 is terminated and a time for state stabilization has elapsed. For example, the OCV of each cell 21 may be acquired at a timing when a predetermined time or more has elapsed after the power switch of the vehicle is turned off. Alternatively, the OCV of each cell 21 may be acquired at a timing, for example, when the vehicle door is opened, before the power switch of the vehicle is turned on.

[0025] The ΔSOC calculation unit 33 calculates, for each cell 21, ΔSOC, which is an amount of SOC change caused by energization of the battery pack 20, based on the SOC of each cell 21 calculated by the SOC calculation unit 32. For example, it is preferable to calculate ΔSOC as the difference between the SOC calculated at the end of the current vehicle travel and the SOC calculated at the end of the previous vehicle travel.

[0026] The second SOH calculation unit 34 uses the above (Equation 4) to calculate the SOH2 of the second cell 21B based on the SOH1 of the first cell 21A calculated by the first SOH calculation unit 31 and the ΔSOC of each cell 21 calculated by the ΔSOC calculation unit 33. As a result, the SOH2 of the second cell 21B is calculated as a value obtained by multiplying the ΔSOC ratio, which is the ratio of ΔSOC1 of the first cell 21A to ΔSOC2 of the second cell 21B, by the SOH1 of the first cell 21A.

[0027] It should be noted that first SOH calculation unit 31 corresponds to a "first calculation unit", SOC calculation unit 32 and ΔSOC calculation unit 33 correspond to a "second calculation unit", and second SOH calculation unit 34 corresponds to a "third calculation unit".

[0028] 4 is a flowchart showing a procedure for calculating the SOH of each battery cell 21. This process is executed by the BMU 30 after, for example, the power switch of the vehicle is turned off.

[0029] 4, in step S11, the battery temperature and impedance of the first cell 21A (the n-2th cell 21), which is a high-temperature battery, are acquired as diagnostic parameters used in deterioration diagnosis. In step S12, the SOH1 of the first cell 21A is calculated based on the diagnostic parameters, for example, using the correlation map in FIG. 2. Note that the calculation timing of SOH1 may be any timing while the power switch is on, as long as the diagnostic parameters can be acquired.

[0030] Thereafter, in step S13, the terminal voltages (OCV) of all the cells 21 are obtained, and in the following step S14, the SOC is calculated for each cell 21 based on the terminal voltage of each cell 21, for example, using the voltage-SOC characteristics shown in Fig. 3. The SOC calculated for each cell 21 may be stored in a backup memory for each vehicle trip. In addition, in step S15, for each cell 21, the difference between the SOC calculated at the end of the current vehicle run and the SOC calculated at the end of the previous vehicle run is calculated as ΔSOC.

[0031] In step S16, it is determined whether or not the ΔSOC calculated in step S15 is equal to or greater than a predetermined threshold value TH1. If the ΔSOC is equal to or greater than the threshold value TH1, the process proceeds to the following step S17. If the ΔSOC is less than the threshold value TH1, the process ends. In step S16, it may be determined whether or not the ΔSOC is equal to or greater than the threshold value TH1 for a specific cell 21 that has been determined in advance, or it may be determined whether or not the minimum SOC or the maximum SOC of all the cells 21 is equal to or greater than the threshold value TH1 (the same applies to step S17 described later).

[0032] In addition, if ΔSOC, which is the difference between the current SOC value and the previous SOC value, is less than threshold value TH1, it is also possible to return to step S15 and calculate ΔSOC as the difference between the current SOC value and the previous or previous SOC value (for example, the value two times ago or the value three times ago), and again determine in step S16 whether ΔSOC is greater than or equal to threshold value TH1.

[0033] In step S17, it is determined whether ΔSOC is less than a predetermined threshold TH2. The threshold TH2 is a value greater than the threshold TH1. If ΔSOC is less than the threshold TH2, the process proceeds to step S18. If ΔSOC is equal to or greater than the threshold TH2, the process proceeds to step S19.

[0034] In step S18, the SOH2 of the second cell 21B is calculated using the above (Equation 4) based on the SOH1 of the first cell 21A calculated in step S12 and the ΔSOC of each cell 21 calculated in step S15.

[0035] In step S19, using the following (Equation 5), the SOH of each cell 21 is calculated for each cell 21 based on the ΔSOC of each cell 21 calculated in step S15 and the current integrated value from the time when the previous SOC was calculated to the time when the current SOC was calculated, which was used to calculate the ΔSOC. SOH = current integrated value / ΔSOC … (Equation 5) In step S19, instead of calculating the SOH of all the cells 21 using (Equation 5), only the SOH2 of the second cell 21B may be calculated using (Equation 5). The current integration value may be calculated by integrating the current flowing through each cell 21 in a current integration process (not shown) and sequentially stored in a backup memory. In (Equation 5), the current integration value in the numerator on the right side may be the current capacity, and ΔSOC in the denominator on the right side may be "ΔSOC × full charge capacity."

[0036] If step S17 is NO, it is also possible to end the process without calculating the SOH2 of the second cell 21B. In Fig. 4, steps S11 and S12 correspond to the "first calculation process", steps S14 and S15 correspond to the "second calculation process", and step S18 corresponds to the "third calculation process".

[0037] According to the present embodiment described above in detail, the following excellent effects can be obtained.

[0038] Among the plurality of cells 21, the cell 21 whose SOH was calculated based on the parameters for deterioration diagnosis was designated as the first cell 21A, and the cell 21 whose SOH was not calculated was designated as the second cell 21B. The SOH2 of the second cell 21B was calculated by multiplying the ΔSOC ratio (change ratio), which is the ratio of ΔSOC1 of the first cell 21A to ΔSOC2 of the second cell 21B, by the SOH1 of the first cell 21A. This makes it possible to calculate the SOH for all the cells 21 even if the parameters for deterioration diagnosis have not been acquired for all the cells 21. As a result, the SOH can be suitably calculated for each cell 21 included in the battery pack 20.

[0039] Among the plurality of cells 21, the high-temperature battery is a cell that is relatively prone to deterioration and is a cell that is highly sensitive to deterioration. In addition, in a battery pack 20 in which a plurality of cells 21 are connected in series, the performance of the battery pack 20 is determined by the cell 21 that is more deteriorated. In consideration of this point, the high-temperature battery is set as the first cell 21A, and the SOH2 of the second cell 21B is calculated based on the ΔSOC ratio (ΔSOC1 / ΔSOC2) of the first cell 21A (high-temperature battery) and the second cell 21B and the SOH1 of the first cell 21A. This makes it possible to perform deterioration diagnosis of the second cell 21B with high accuracy based on the cell that is estimated to be more deteriorated. In addition, since the IR drop (voltage drop due to path resistance), which is an error factor, is small in the high-temperature battery, improvement in the accuracy of SOH can also be expected.

[0040] When ΔSOC of the cell 21 is larger than a predetermined value, instead of calculating SOH2 of the second cell 21B using ΔSOC1 and SOH1 of the first cell 21A (calculating SOH2 using (Equation 4)), the SOH of each cell 21 is calculated based on ΔSOC and the current integrated value (calculating SOH using (Equation 5)). This makes it possible to properly calculate the SOH of each cell 21 regardless of the magnitude of ΔSOC (amount of SOC change).

[0041] As a modification of the first embodiment, the following configuration is also possible.

[0042] 5 is a configuration diagram of the battery system 10 in this modification. In FIG. 5, the difference from FIG. 1 is that, among the n cells 21, the cell 21 that becomes the coldest when the assembled battery 20 is energized (when charging or discharging) is designated as the first cell 21A, and the temperature sensor 25 detects the temperature and the impedance sensor 26 detects the impedance of the first cell 21A. Specifically, among the n cells 21 shown in FIG. 5, the nth cell 21 is designated as the cell 21 that becomes the coldest when the assembled battery 20 is energized, and the nth cell 21 is designated as the first cell 21A, and the other cells 21 are designated as the second cell 21B. The first cell 21A may be determined from among the cells 21 that becomes a low-temperature battery that becomes relatively low temperature when the assembled battery 20 is energized, and may be, for example, the cell 21 that becomes low temperature relative to the average temperature of all the cells 21.

[0043] The procedure for calculating the SOH of each cell 21 by the BMU 30 is generally as shown in Fig. 4. To summarize the differences, in Fig. 4, in steps S11 and S12, the battery temperature and impedance are acquired for the first cell 21A (cell 21 number n), which is a low-temperature battery, and SOH1 is calculated. Also, in step S18, SOH2 of the second cell 21B (cell 21 other than cell 21 number n) is calculated based on SOH1 of the first cell 21A (cell 21 number n) and ΔSOC of each cell 21 in the above (Equation 4).

[0044] Since the low-temperature battery among the plurality of cells 21 has a larger impedance than the high-temperature battery, the impedance, which is a parameter for deterioration diagnosis, can be detected with relatively high accuracy. With attention to this point, the low-temperature battery is set as the first cell 21A, and the SOH2 of the second cell 21B is calculated based on the ΔSOC ratio (ΔSOC1 / ΔSOC2) of the first cell 21A (low-temperature battery) and the second cell 21B and the SOH1 of the first cell 21A. This makes it possible to accurately calculate the SOH1 of the first cell 21A, and therefore to perform deterioration diagnosis of the second cell 21B with high accuracy.

[0045] As shown in FIG. 6, the cells 21 of the battery pack 20 may be divided into a plurality of battery groups G1-Gn having relatively different temperatures when the battery pack 20 is in a powered state, and a specific cell 21X that enables parameter detection by the temperature sensor 25 and the impedance sensor 26 may be determined for each battery group G1-Gn. The specific cell 21X may be a high-temperature battery that is relatively hot or a low-temperature battery that is relatively cold, as long as it is determined for each battery group G1-Gn. The number of cells 21 in each battery group G1-Gn may be the same or different. For example, in a battery group G1-Gn in which the temperature difference between the highest temperature cell 21 and the lowest temperature cell 21 is large, the number of cells 21 may be smaller than that in a battery group in which the temperature difference is small.

[0046] The BMU 30 may execute the SOH calculation process shown in Fig. 4 for each of the battery groups G1-Gn, with the specific cell 21X as the first cell 21A. In this case, for each of the battery groups G1-Gn, the BMU 30 calculates the SOH1 of the first cell 21A based on the deterioration diagnosis parameters detected in the first cell 21A (specific cell 21X), and uses the SOH1 to calculate the SOH2 of the second cell 21B.

[0047] Hereinafter, the other embodiments will be described, focusing on the differences from the first embodiment.

[0048] Second embodiment FIG. 7 is a configuration diagram of the battery system 10 in this embodiment. In FIG. 7, the difference from FIG. 1 is that, among the n cells 21, the cell 21 that becomes the hottest and the cell 21 that becomes the coldest when the battery pack 20 is energized are designated as the first cell 21A, and the temperature sensor 25 detects the temperature and the impedance sensor 26 detects the impedance of the two first cells 21A. Specifically, in the energized state of the battery pack 20, the n-2 cell 21 is the high-temperature battery that becomes the hottest, and the n cell 21 is the low-temperature battery that becomes the coldest, and the n-2 and n cells 21 are designated as the first cell 21A, and the cells 21 other than the n-2 and n are designated as the second cell 21B. The high-temperature battery and the low-temperature battery may be the high-temperature battery that becomes relatively hot and the low-temperature battery that becomes relatively cold when the battery pack 20 is energized.

[0049] In this embodiment, for each second cell 21B, a first cell 21A with a small temperature difference is combined with the battery pack 20 in a powered state, and the SOH2 of the second cell 21B is calculated using ΔSOC1 and SOH1 of the combined first cell 21A. Note that it is preferable to determine in advance whether each second cell 21B (cells 21 other than n-2 and nth cell) is to be combined with a first cell 21A on the low temperature side or a first cell 21A on the high temperature side.

[0050] In this embodiment, the method of calculating the SOH2 of the second cell 21B is changed depending on whether the battery pack temperature Tb, which is the temperature of the entire battery pack 20, is lower or higher than a predetermined temperature. Specifically, if the battery pack temperature Tb is lower than the predetermined temperature, the low-temperature battery is set as the first cell 21A, and the SOH2 of the second cell 21B is calculated based on the SOH1 of the first cell 21A. On the other hand, if the battery pack temperature Tb is higher than the predetermined temperature, the first cell 21A with the smaller temperature difference between the low-temperature side first cell 21A and the high-temperature side first cell 21A is combined for each second cell 21B, and the SOH2 of the second cell 21B is calculated based on the SOH1 of the first cell 21A.

[0051] The battery pack temperature Tb may be the detection value of a temperature sensor 25 provided in any one of the n cells 21, or the detection value of an outside air temperature sensor may be used, assuming that the temperature of the battery pack 20 has dropped sufficiently after use of the battery pack 20 has ended.

[0052] Fig. 8 is a flowchart showing the SOH calculation process in this embodiment. This process is executed by the BMU 30, replacing Fig. 4. Note that in Fig. 8, the same processes as those in Fig. 4 are given the same step numbers and detailed descriptions are omitted.

[0053] 8, in steps S11 and S12, the battery temperature and impedance are acquired as parameters used in the deterioration diagnosis for the two first cells 21A, and SOH1 is calculated based on the diagnosis parameters. At this time, SOH1 is calculated for each of the first cells 21A, which is a high-temperature battery, and the first cells 21A, which is a low-temperature battery. Thereafter, in steps S13 to S15, the SOC is calculated based on the terminal voltage (OCV) for each cell 21, and the difference between the SOC at the end of the current vehicle running and the SOC at the end of the previous vehicle running is calculated as ΔSOC. Thereafter, if it is determined in step S16 that ΔSOC is equal to or greater than the threshold value TH1 and if it is determined in step S17 that ΔSOC is less than the threshold value TH2, the process proceeds to step S21.

[0054] In step S21, it is determined whether the battery pack temperature Tb is lower than a predetermined temperature threshold KT. The temperature threshold KT is, for example, 0° C. Then, if it is determined that the battery pack temperature Tb is lower than the temperature threshold KT, the process proceeds to step S22, and the first cell 21A that is the low-temperature battery (the n-th cell 21) of the two first cells 21A is determined as the first cell 21A that refers to SOH1. If it is determined that the battery pack temperature Tb is higher than the temperature threshold KT, the process proceeds to step S23, and for each second cell 21B, the first cell 21A that is the low-temperature battery (the n-th cell 21) or the high-temperature battery (the n-2-th cell 21) that has a smaller temperature difference with the second cell 21B is determined as the first cell 21A that refers to SOH1.

[0055] After that, in step S18, the SOH2 of the second cell 21B is calculated by referring to ΔSOC and SOH1 of the first cell 21A determined in steps S21 to S23 and using the above (Equation 4).

[0056] The effects of the second embodiment described above in detail will be described below.

[0057] Since the voltage-SOC characteristics of the battery pack 20 are temperature dependent, the cells 21 that are close in temperature to each other when the battery pack 20 is energized will have similar voltage-SOC characteristics. In this case, if the first cell 21A and the second cell 21B are combined with cells 21 that have a small temperature difference, the SOC errors generated in the cells 21A and 21B will be similar, and the same errors will be applied to the denominator and numerator of the ΔSOC ratio in the above (Equation 4). Therefore, the ΔSOC ratio is less susceptible to temperature. In view of this, for each second cell 21B, the SOH2 of the second cell 21B is calculated using the ΔSOC1 and SOH1 of the first cell 21A that has a small temperature difference with the second cell 21B when the battery pack 20 is energized. As a result, even if there is a large temperature difference between the cells 21 in the entire battery pack 20, the accuracy of the SOH calculation can be ensured, and the SOH of all the cells 21 can be calculated appropriately.

[0058] When the battery pack 20 is in a low-temperature state, the impedance of the battery 21 at the lower temperature side among the plurality of cells 21 is detected more accurately, and the SOH1 of the first cell 21A is calculated more accurately. On the other hand, when the battery pack 20 is not in a low-temperature state, the advantage of using the low-temperature battery as a reference is reduced. In consideration of this point, when it is determined that the battery pack temperature Tb is lower than the temperature threshold KT (predetermined temperature), the low-temperature battery is set as the first cell 21A, and the SOH2 of the second cell 21B is calculated based on the SOH1 of the first cell 21A, while when it is determined that the battery pack temperature Tb is higher than the temperature threshold KT, the ΔSOC1 and SOH1 of the first cell 21A, which has a smaller temperature difference from the second cell 21B, are used to calculate the SOH2 of the second cell 21B for each second cell 21B. This allows the SOH of each cell 21 to be calculated appropriately whether the battery pack 20 is in a low-temperature state or not.

[0059] As a modification of the second embodiment, the following configuration is also possible.

[0060] Of the n cells 21, three or more cells 21 having different battery temperatures when the battery pack 20 is energized may be designated as first cells 21A. For example, when three cells 21 are designated as first cells 21A, for each second cell 21B, SOH2 of the second cell 21B may be calculated using ΔSOC1 and SOH1 of the first cell 21A that has the smallest temperature difference with the second cell 21B among the three first cells 21A.

[0061] 8, the processes of steps S21 and S22 may be omitted. In this case, if it is determined in step S16 that ΔSOC is equal to or greater than the threshold value TH1 and in step S17 that ΔSOC is less than the threshold value TH2, the process proceeds to step S23, where, for each second cell 21B, the cell 21 having the smaller temperature difference from the second cell 21B among the low-temperature cell (the n-th cell 21) and the high-temperature cell (the n-2-th cell 21) is determined as the first cell 21A for which SOH1 is to be referenced. In the following step S18, the SOH2 of the second cell 21B is calculated by referring to ΔSOC1 and SOH1 of the first cell 21A determined in step S23 and using the above (Equation 4).

[0062] Third embodiment In this embodiment, a temperature sensor 25 and an impedance sensor 26 are provided in all of the cells 21 of the battery pack 20. That is, the diagnostic parameters of battery temperature and impedance are detected in all of the cells 21. In this embodiment, when it is determined that a sensor abnormality has occurred in any of the cells 21, the cell 21 in which the sensor abnormality has occurred is designated as the second cell 21B, while the cell 21 in which it is determined that no sensor abnormality has occurred is designated as the first cell 21A, and the SOH2 of the second cell 21B is calculated.

[0063] Fig. 9 is a flowchart showing the SOH calculation process in this embodiment. This process is executed by the BMU 30, replacing Fig. 4. Note that in Fig. 9, the same processes as those in Fig. 4 are given the same step numbers and detailed descriptions are omitted.

[0064] 9, in steps S11 and S12, the battery temperature and impedance are acquired as parameters used in the deterioration diagnosis for the first cell 21A, and the SOH1 is calculated based on the diagnosis parameters. At this time, all the cells 21 are regarded as the first cells 21A, and the SOH1 is calculated for each cell 21.

[0065] Thereafter, in step S31, it is determined whether or not an abnormality has occurred in the temperature sensor 25 and the impedance sensor 26 provided in each battery cell 21. The abnormality determination may be performed by any method, but for example, it may be determined that a sensor abnormality has occurred when the detection value of the temperature sensor 25 is outside a specified range, or when the deviation amount of the detection value in each battery cell 21 from the average value is equal to or greater than a predetermined value. Then, if step S31 is negative, this process ends as it is. On the other hand, if step S31 is positive, the process proceeds to step S32.

[0066] In step S32, the cell 21 determined to have a sensor abnormality is designated as the second cell 21B. In step S33, any of the normal cells 21 not determined to have a sensor abnormality is determined as the first cell 21A for referencing SOH1. Specifically, among the normal cells 21, the cell 21 having the smallest temperature difference from the cell 21 having a sensor abnormality is determined as the first cell 21A for referencing SOH1. Alternatively, among the normal cells 21, a high-temperature cell (e.g., the cell 21 with the highest temperature) or a low-temperature cell (e.g., the cell 21 with the lowest temperature) can be determined as the first cell 21A for referencing SOH1.

[0067] Thereafter, in steps S13 to S15, the SOC is calculated for each cell 21 based on the terminal voltage (OCV), and the difference between the SOC at the end of the current vehicle run and the SOC at the end of the previous vehicle run is calculated as ΔSOC. If it is determined in step S16 that ΔSOC is equal to or greater than the threshold value TH1 and if it is determined in step S17 that ΔSOC is less than the threshold value TH2, the process proceeds to step S18. In step S18, the SOH2 of the second cell 21B (i.e., the cell 21 with the sensor abnormality) is calculated by referring to the ΔSOC1 and SOH1 of the first cell 21A determined in step S33 and using the above (Equation 4).

[0068] In the third embodiment described above in detail, it is determined whether or not a sensor abnormality has occurred for each of the temperature sensor 25 and the impedance sensor 26 provided in each cell 21, and the cell 21 determined to have a sensor abnormality is designated as the second cell 21B, while the cell 21 determined to have no sensor abnormality is designated as the first cell 21A. Then, the SOH2 of the second cell 21B is calculated based on ΔSOC1 and SOH1 of the first cell 21A determined to have no sensor abnormality. In this case, even after the SOH calculation becomes impossible due to the sensor abnormality in the cell 21 that was initially capable of calculating the SOH based on the sensor detection information, the SOH can be continuously calculated.

[0069] In this embodiment, instead of providing the temperature sensor 25 and the impedance sensor 26 to all of the cells 21 of the battery pack 20, the temperature sensor 25 and the impedance sensor 26 may be provided to at least some of two or more cells 21. In this case, similar to the above, the cell 21 determined to have a sensor abnormality may be designated as the second cell 21B, while the cell 21 determined not to have a sensor abnormality may be designated as the first cell 21A.

[0070] (Other embodiments) The above embodiment may be modified, for example, as follows.

[0071] In the SOH calculation process described with reference to Fig. 4 etc., a condition for permission or prohibition may be set for calculating the SOH2 of the second cell 21B by the above (Equation 4). For example, a prohibition condition for prohibiting the calculation of the SOH2 of the second cell 21B may be set based on the voltage-SOC characteristic line of the cell 21 shown in Fig. 10.

[0072] In this case, in step S14 of FIG. 4, the BMU 30 uses the voltage-SOC characteristic line to calculate the SOC based on the terminal voltage of the cell 21, and calculates ΔSOC (amount of SOC change) that occurs with the passage of current through the battery pack 20. In addition, in the voltage-SOC characteristic line shown in FIG. 10, the region where the slope of the voltage with respect to the SOC is equal to or less than a predetermined value is the flat region Rf, and the BMU 30 determines in step S18 whether the terminal voltage of the cell 21 is in the flat region Rf (voltage determination unit). Then, when it is determined that the terminal voltage is in the flat region Rf, the BMU 30 does not calculate the SOH2 of the second cell 21B. Or, even if the BMU 30 calculates the SOH2 of the second cell 21B, it invalidates the calculation. In other words, when the terminal voltage of the cell 21 is in the flat region Rf, the calculation of the SOH2 of the second cell 21B is not valid.

[0073] In the voltage-SOC characteristic line of the cell 21, when the terminal voltage of the cell 21 is in a flat region Rf, the change in SOC is small even if the terminal voltage of the cell 21 changes, making it difficult to ensure the calculation accuracy of the SOC. Therefore, when it is determined that the terminal voltage of the cell 21 is in the flat region Rf in the voltage-SOC characteristic line of the cell 21, the calculation of the SOH2 of the second cell 21B is not valid. This makes it possible to suppress inconveniences such as a decrease in the calculation accuracy of the SOH2 of the second cell 21B due to a low calculation accuracy of the SOC of the cell 21.

[0074] Also, since the accuracy of calculating the SOC decreases immediately after charging or discharging the cell 21, it is possible to configure the calculation of the SOH2 of the second cell 21B to be prohibited (invalidated) for a predetermined period immediately after charging or discharging. For example, when an equalization process (cell balancing process) for equalizing the terminal voltages of each cell 21 is performed, the BMU 30 prohibits the calculation of the SOH2 of the second cell 21B until a predetermined time has elapsed.

[0075] As shown in Fig. 11, the battery system 10 may be configured to include a plurality of voltage sensors 24 for detecting the terminal voltages of the cells 21, and the terminal voltage of each cell 21 may be detected by one of the voltage sensors 24. In Fig. 11, the second cell 21 and the n-1th cell 21 are first cells 21A for which SOH can be calculated using diagnostic parameters. At least two cells 21 may be defined as the first cells 21A. In this case, the first cell 21A and the second cell 21B may be combined as cells 21 whose voltages are detected by the same voltage sensor 24, and the SOH2 of the second cell 21B may be calculated based on the SOH1 of the first cell 21A.

[0076] 4, for example, the BMU 30 calculates the SOH1 of each first cell 21A (step S12). The BMU 30 also calculates the SOC based on the voltage detected by the voltage sensor 24, and calculates ΔSOC from the SOC before and after a change associated with energization of the battery pack 20 (steps S13 to S15). For each second cell 21B, the BMU 30 combines the first cells 21A whose voltages are detected by the same voltage sensor 24, and calculates the SOH2 of the second cells 21B using ΔSOC1 and SOH1 of the first cells 21A (step S18).

[0077] In a configuration in which the terminal voltages of the cells 21 in the assembled battery 20 are detected by a plurality of voltage sensors 24, the detection errors are equivalent when the voltages are detected by the same voltage sensor 24. In this case, if the first cell 21A and the second cell 21B are combined with the cells 21 whose voltages are detected by the same voltage sensor 24, the SOC errors occurring in the cells 21A and 21B are equivalent, and the same errors are added to the denominator and numerator of the ΔSOC ratio in the above (Equation 4). Therefore, the ΔSOC ratio is less susceptible to the voltage detection error. In view of this, for each second cell 21B, the SOH2 of the second cell 21B is calculated using the ΔSOC1 and SOH1 of the first cell 21A whose voltage is detected by the same voltage sensor 24. This ensures the accuracy of the SOH calculation, and the SOH of all the cells 21 can be calculated appropriately.

[0078] The SOH calculation process in Fig. 4 etc. may be performed while the vehicle power switch is on (while the vehicle is running). In this case, while the vehicle is running, the voltage and current are measured at multiple points for each cell 21, the OCV is calculated from the intercept when the voltage and current are plotted on a two-dimensional coordinate system, and the SOC of each cell 21 is calculated based on the OCV.

[0079] A configuration may be adopted in which only the impedance sensor 26 is provided as a detection unit for detecting the diagnostic parameters. Also, a configuration may be adopted in which only a portion of all the cells 21 are defined as the first cells 21A, and impedance detection is performed on the first cells 21A.

[0080] The battery system 10 is not limited to being mounted on a vehicle, but may be mounted on other moving objects such as aircraft, ships, etc. Also, the battery system 10 is not limited to being mounted on a moving object, but may be a stationary system.

[0081] The control unit and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described in the present disclosure may be realized by one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer.

[0082] The technical ideas extracted from the above-described embodiments will be described below. [Configuration 1] A battery diagnosis device (30) is applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and detecting a parameter for deterioration diagnosis, the battery diagnosis device (30) calculating a state of health (SOH) indicating a degree of deterioration of each of the unit cells, a first calculation unit that acquires the parameter detected by the detection unit for at least one of the plurality of unit cells and calculates the SOH based on the parameter; A second calculation unit that calculates a change in SOC caused by energization of the plurality of single cells; a third calculation unit that calculates, when a cell of the plurality of cells for which the SOH has been calculated by the first calculation unit is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell, a value obtained by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, by the SOH of the first cell, as the SOH of the second cell; A battery diagnostic device comprising: [Configuration 2] the first calculation unit acquires the parameters detected by the detection unit for a high-temperature battery that is relatively hot when the battery pack is in a current-carrying state among the plurality of single cells, and calculates the SOH of the high-temperature battery based on the parameters; 2. The battery diagnosis device according to configuration 1, wherein the third calculation unit calculates the SOH of the second cell by treating the high-temperature battery as the first cell. [Configuration 3] the first calculation unit acquires the parameters detected by the detection unit for a low-temperature battery among the plurality of single cells that has a relatively low temperature when the battery pack is in a powered state, and calculates the SOH of the low-temperature battery based on the parameters; 2. The battery diagnosis device according to configuration 1, wherein the third calculation unit calculates the SOH of the second cell by treating the low temperature battery as the first cell. [Configuration 4] the first calculation unit, for at least two of the plurality of cells as the first cells, acquires the parameters detected by the detection unit, and calculates the SOH based on the parameters; The battery diagnosis device of configuration 1, wherein the third calculation unit calculates, for each of the second cells, the SOH of a first cell that has a smaller temperature difference from the second cell when the battery pack is in a powered state, among the at least two of the first cells, by using the SOC change amount and the SOH of the first cell. [Configuration 5] the first calculation unit determines, as first cells, two or more cells including a low-temperature battery that has a relatively low temperature when the battery pack is in a powered state among the plurality of cells, and acquires the parameters detected by the detection unit and calculates the SOH based on the parameters; a temperature determination unit that determines whether a battery pack temperature, which is a temperature of the entire battery pack, is higher or lower than a predetermined temperature; The third calculation unit is When it is determined that the battery pack temperature is lower than the predetermined temperature, the low-temperature battery is regarded as the first battery and the SOH of the second battery is calculated; the SOC change amount and the SOH of a first cell that has a smaller temperature difference from the second cell when the battery pack temperature is determined to be higher than the predetermined temperature, among the two or more first cells, when the battery pack is in a powered state, are used to calculate the SOH of the second cell. [Configuration 6] the battery system is provided with a plurality of voltage sensors (24) for detecting terminal voltages of the individual cells; the first calculation unit, for at least two of the plurality of cells as the first cells, acquires the parameters detected by the detection unit, and calculates the SOH based on the parameters; the second calculation unit calculates an SOC based on a detected voltage of the voltage sensor, and calculates an amount of change in the SOC based on the SOC before and after a change caused by energization of the battery pack; The battery diagnosis device of configuration 1, wherein the third calculation unit, for each of the second cells, combines a first cell among at least two of the first cells whose voltage is detected by the same voltage sensor, and calculates the SOH of the second cell using the SOC change amount and the SOH of the first cell. [Configuration 7] In the battery system, the detection unit is provided in at least two of the plurality of unit cells, an abnormality determination unit that determines whether or not an abnormality occurs in the detection unit in the battery provided with the detection unit, The battery diagnosis device of any one of configurations 1 to 6, wherein the third calculation unit determines that the cell determined by the abnormality determination unit that the detection unit has an abnormality as the second cell, and determines that the cell is provided with the detection unit and that the detection unit has not an abnormality as the first cell, and calculates the SOH of the second cell. [Configuration 8] a voltage determination unit that determines whether or not the voltage of the battery cell is in a flat region in which a slope of the voltage with respect to the SOC is equal to or less than a predetermined value in a voltage-SOC characteristic line that indicates the relationship between the voltage of the battery cell and the SOC; the second calculation unit calculates an SOC based on a voltage of the battery cell using the voltage-SOC characteristic line, and calculates an amount of change in the SOC based on the SOC before and after a change caused by energization of the battery pack; The battery diagnostic device according to any one of configurations 1 to 7, wherein the third calculation unit does not validate the calculation of the SOH of the second battery cell when it is determined that the voltage of the battery cell is in the flat region. [Configuration 9] a change amount determination unit that determines whether the SOC change amount calculated by the second calculation unit is greater than a predetermined value; a fourth calculation unit that calculates the SOH based on the SOC change amount and an integrated value of a current flowing through the battery cell within a period during which the SOC change amount is calculated, instead of the calculation of the SOH by the third calculation unit, when the change amount determination unit determines that the SOC change amount is greater than a predetermined value; The battery diagnostic device according to any one of configurations 1 to 8, comprising: [Explanation of symbols]

[0083] 10...battery system, 20...battery pack, 21...cell, 25...temperature sensor, 26...impedance sensor, 30...BMU.

Claims

1. A battery diagnosis device (30) is applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and detecting a parameter for deterioration diagnosis, the battery diagnosis device (30) calculating a SOH indicating a degree of deterioration of each of the unit cells, a first calculation unit that acquires the parameter detected by the detection unit for at least one of the plurality of unit cells and calculates the SOH based on the parameter; A second calculation unit that calculates an amount of change in SOC caused by energization of the plurality of single cells; a third calculation unit that calculates, as the SOH of the second cell, a value obtained by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, when a cell of the plurality of cells for which the SOH has been calculated by the first calculation unit is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell; and Equipped with the first calculation unit acquires the parameters detected by the detection unit for a high-temperature battery that is relatively hot when the battery pack is in a current-carrying state among the plurality of single cells, and calculates the SOH of the high-temperature battery based on the parameters; The third calculation unit calculates the SOH of the second cell by treating the high temperature battery as the first cell.

2. A battery diagnosis device (30) is applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and detecting a parameter for deterioration diagnosis, the battery diagnosis device (30) calculating a SOH indicating a degree of deterioration of each of the unit cells, a first calculation unit that acquires the parameter detected by the detection unit for at least one of the plurality of unit cells and calculates the SOH based on the parameter; A second calculation unit that calculates an amount of change in SOC caused by energization of the plurality of single cells; a third calculation unit that calculates, as the SOH of the second cell, a value obtained by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, when a cell of the plurality of cells for which the SOH has been calculated by the first calculation unit is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell; and Equipped with the first calculation unit acquires the parameters detected by the detection unit for a low-temperature battery among the plurality of single cells that has a relatively low temperature when the battery pack is in a powered state, and calculates the SOH of the low-temperature battery based on the parameters; The third calculation unit calculates the SOH of the second cell by treating the low temperature battery as the first cell.

3. A battery diagnosis device (30) is applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and detecting a parameter for deterioration diagnosis, the battery diagnosis device (30) calculating a SOH indicating a degree of deterioration of each of the unit cells, a first calculation unit that acquires the parameter detected by the detection unit for at least one of the plurality of unit cells and calculates the SOH based on the parameter; A second calculation unit that calculates an amount of change in SOC caused by energization of the plurality of single cells; a third calculation unit that calculates, as the SOH of the second cell, a value obtained by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, when a cell of the plurality of cells for which the SOH has been calculated by the first calculation unit is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell; and Equipped with the first calculation unit, for at least two of the plurality of cells as the first cells, acquires the parameters detected by the detection unit, and calculates the SOH based on the parameters; The third calculation unit calculates, for each of the second cells, the SOH of the second cell by using the SOC change amount and the SOH of a first cell that has a smaller temperature difference from the second cell when the battery pack is in a powered state, among the at least two first cells.

4. A battery diagnosis device (30) is applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and detecting a parameter for deterioration diagnosis, the battery diagnosis device (30) calculating a SOH indicating a degree of deterioration of each of the unit cells, a first calculation unit that acquires the parameter detected by the detection unit for at least one of the plurality of unit cells and calculates the SOH based on the parameter; A second calculation unit that calculates an amount of change in SOC caused by energization of the plurality of single cells; a third calculation unit that calculates, as the SOH of the second cell, a value obtained by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, when a cell of the plurality of cells for which the SOH has been calculated by the first calculation unit is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell; and Equipped with the first calculation unit determines, as first cells, two or more cells including a low-temperature battery that has a relatively low temperature when the battery pack is in a powered state among the plurality of cells, and acquires the parameters detected by the detection unit and calculates the SOH based on the parameters; a temperature determination unit that determines whether a battery pack temperature, which is a temperature of the entire battery pack, is higher or lower than a predetermined temperature; The third calculation unit is When it is determined that the battery pack temperature is lower than the predetermined temperature, the low-temperature battery is regarded as the first battery and the SOH of the second battery is calculated; and when it is determined that the temperature of the battery pack is higher than the predetermined temperature, the battery diagnosis device calculates, for each of the second cells, the SOH and the SOC change of a first cell among the two or more first cells that has a small temperature difference from the second cell when the battery pack is in a powered state.

5. A battery diagnosis device (30) is applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and detecting a parameter for deterioration diagnosis, the battery diagnosis device (30) calculating a SOH indicating a degree of deterioration of each of the unit cells, The battery system is provided with a plurality of voltage sensors (24) for detecting terminal voltages of the individual cells, a first calculation unit that acquires the parameter detected by the detection unit for at least one of the plurality of unit cells and calculates the SOH based on the parameter; A second calculation unit that calculates an amount of change in SOC caused by energization of the plurality of single cells; a third calculation unit that calculates, as the SOH of the second cell, a value obtained by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, when a cell of the plurality of cells for which the SOH has been calculated by the first calculation unit is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell; and Equipped with the first calculation unit, for at least two of the plurality of cells as the first cells, acquires the parameters detected by the detection unit, and calculates the SOH based on the parameters; the second calculation unit calculates an SOC based on a detected voltage of the voltage sensor, and calculates an amount of change in SOC based on the SOC before and after a change caused by energization of the battery pack; The third calculation unit, for each of the second cells, combines a first cell among at least two of the first cells whose voltage is detected by the same voltage sensor, and calculates the SOH of the second cell using the SOC change amount and the SOH of the first cell.

6. In the battery system, the detection unit is provided in at least two of the plurality of unit cells, an abnormality determination unit that determines whether or not an abnormality occurs in the detection unit in the battery provided with the detection unit, The battery diagnosis device according to any one of claims 1 to 5, wherein the third calculation unit calculates the SOH of the second battery by determining that the battery is abnormal in the detection unit by the abnormality determination unit as the second battery, and by determining that the battery is provided with the detection unit and that the detection unit is not abnormal as the first battery.

7. a voltage determination unit that determines whether or not the voltage of the battery cell is in a flat region in which a slope of the voltage with respect to the SOC is equal to or less than a predetermined value in a voltage-SOC characteristic line that indicates a relationship between the voltage of the battery cell and the SOC; the second calculation unit calculates an SOC based on a voltage of the battery cell using the voltage-SOC characteristic line, and calculates an amount of change in SOC based on the SOC before and after a change caused by energization of the battery pack; The battery diagnosis device according to any one of claims 1 to 5, wherein the third calculation unit does not validate the calculation of the SOH of the second battery cell when it is determined that the voltage of the battery cell is in the flat region.

8. a change amount determination unit that determines whether the SOC change amount calculated by the second calculation unit is greater than a predetermined value; a fourth calculation unit that calculates the SOH based on the SOC change amount and an integrated value of a current flowing through the battery cell within a period during which the SOC change amount is calculated, instead of the calculation of the SOH by the third calculation unit, when the change amount determination unit determines that the SOC change amount is greater than a predetermined value; The battery diagnostic device according to any one of claims 1 to 5, comprising:

9. A battery diagnosis device (30) is applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and detecting a parameter for deterioration diagnosis, the battery diagnosis device (30) calculating a SOH indicating a degree of deterioration of each of the unit cells, In the battery system, the detection unit is provided in at least two of the plurality of unit cells, a first calculation unit that acquires the parameter detected by the detection unit for at least one of the plurality of unit cells and calculates the SOH based on the parameter; A second calculation unit that calculates an amount of change in SOC caused by energization of the plurality of single cells; a third calculation unit that calculates, as the SOH of the second cell, a value obtained by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, when a cell of the plurality of cells for which the SOH has been calculated by the first calculation unit is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell; and an abnormality determination unit that determines whether or not an abnormality occurs in the detection unit in the battery in which the detection unit is provided; Equipped with The third calculation unit calculates the SOH of the second battery by designating the battery for which the abnormality determination unit has determined that an abnormality has occurred in the detection unit as the second battery, and by designating the battery for which the detection unit is provided and for which it has been determined that no abnormality has occurred in the detection unit as the first battery.

10. A battery diagnosis device (30) is applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and detecting a parameter for deterioration diagnosis, the battery diagnosis device (30) calculating a SOH indicating a degree of deterioration of each of the unit cells, a first calculation unit that acquires the parameter detected by the detection unit for at least one of the plurality of unit cells and calculates the SOH based on the parameter; A second calculation unit that calculates an amount of change in SOC caused by energization of the plurality of single cells; a third calculation unit that calculates, as the SOH of the second cell, a value obtained by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, when a cell of the plurality of cells for which the SOH has been calculated by the first calculation unit is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell; and a voltage determination unit that determines whether the voltage of the battery cell is in a flat region in which the slope of the voltage with respect to the SOC is equal to or smaller than a predetermined value in a voltage-SOC characteristic line that indicates the relationship between the voltage of the battery cell and the SOC; Equipped with the second calculation unit calculates an SOC based on a voltage of the battery cell using the voltage-SOC characteristic line, and calculates an amount of change in SOC based on the SOC before and after a change caused by energization of the battery pack; The third calculation unit invalidates the calculation of the SOH of the second battery cell when it is determined that the voltage of the battery cell is in the flat region.

11. A battery diagnosis device (30) is applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and detecting a parameter for deterioration diagnosis, the battery diagnosis device (30) calculating a SOH indicating a degree of deterioration of each of the unit cells, a first calculation unit that acquires the parameter detected by the detection unit for at least one of the plurality of unit cells and calculates the SOH based on the parameter; A second calculation unit that calculates an amount of change in SOC caused by energization of the plurality of single cells; a third calculation unit that calculates, as the SOH of the second cell, a value obtained by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, when a cell of the plurality of cells for which the SOH has been calculated by the first calculation unit is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell; and a change amount determination unit that determines whether the SOC change amount calculated by the second calculation unit is greater than a predetermined value; a fourth calculation unit that calculates the SOH based on the SOC change amount and an integrated value of a current flowing through the battery cell within a period during which the SOC change amount is calculated, instead of the calculation of the SOH by the third calculation unit, when the change amount determination unit determines that the SOC change amount is greater than a predetermined value; A battery diagnostic device comprising:

12. A program applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and configured to detect a parameter for deterioration diagnosis, the program being executed by a control device (30) to calculate a state of health (SOH) indicating a degree of deterioration of each of the unit cells, a first calculation process of acquiring the parameter detected by the detection unit for at least one of the plurality of unit cells and calculating the SOH based on the parameter; A second calculation process of calculating an amount of change in SOC caused by energization of the plurality of single cells; a third calculation process in which, when a cell among the plurality of cells for which the SOH has been calculated by the first calculation process is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell, the SOH of the second cell is calculated by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, by the SOH of the first cell; Equipped with In the first calculation process, the parameters detected by the detection unit are acquired for a high-temperature battery that is relatively hot when the battery pack is in a current-carrying state among the plurality of single cells, and the SOH of the high-temperature battery is calculated based on the parameters; In the third calculation process, the high temperature battery is regarded as the first cell and the SOH of the second cell is calculated.

13. A program applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and configured to detect a parameter for deterioration diagnosis, the program being executed by a control device (30) to calculate a state of health (SOH) indicating a degree of deterioration of each of the unit cells, a first calculation process of acquiring the parameter detected by the detection unit for at least one of the plurality of unit cells and calculating the SOH based on the parameter; A second calculation process of calculating an amount of change in SOC caused by energization of the plurality of single cells; a third calculation process in which, when a cell among the plurality of cells for which the SOH has been calculated by the first calculation process is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell, the SOH of the second cell is calculated by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, by the SOH of the first cell; Equipped with In the first calculation process, the parameters detected by the detection unit are acquired for a low-temperature battery among the plurality of single cells that has a relatively low temperature when the battery pack is in a powered state, and the SOH of the low-temperature battery is calculated based on the parameters; In the third calculation process, the low temperature battery is regarded as the first cell and the SOH of the second cell is calculated.

14. A program applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and configured to detect a parameter for deterioration diagnosis, the program being executed by a control device (30) to calculate a state of health (SOH) indicating a degree of deterioration of each of the unit cells, a first calculation process of acquiring the parameter detected by the detection unit for at least one of the plurality of unit cells and calculating the SOH based on the parameter; A second calculation process of calculating an amount of change in SOC caused by energization of the plurality of single cells; a third calculation process in which, when a cell among the plurality of cells for which the SOH has been calculated by the first calculation process is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell, the SOH of the second cell is calculated by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, by the SOH of the first cell; Equipped with In the first calculation process, at least two of the plurality of cells are set as first cells, the parameters detected by the detection unit are acquired, and the SOH is calculated based on the parameters; In the third calculation process, a program is provided for calculating, for each of the second cells, the SOH of the second cell is calculated using the SOC change amount and the SOH of a first cell, among at least two of the first cells, that has a smaller temperature difference from the second cell when the battery pack is in a powered state.

15. A program applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and configured to detect a parameter for deterioration diagnosis, the program being executed by a control device (30) to calculate a state of health (SOH) indicating a degree of deterioration of each of the unit cells, a first calculation process of acquiring the parameter detected by the detection unit for at least one of the plurality of unit cells and calculating the SOH based on the parameter; A second calculation process of calculating an amount of change in SOC caused by energization of the plurality of single cells; a third calculation process in which, when a cell among the plurality of cells for which the SOH has been calculated by the first calculation process is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell, the SOH of the second cell is calculated by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, by the SOH of the first cell; Equipped with the first calculation process is for determining, as first cells, two or more cells including a low-temperature battery that has a relatively low temperature when the battery pack is in a power-on state among the plurality of cells, and acquiring the parameters detected by the detection unit and calculating the SOH based on the parameters; a temperature determination process for determining whether a battery pack temperature, which is a temperature of the entire battery pack, is higher or lower than a predetermined temperature; In the third calculation process, When it is determined that the battery pack temperature is lower than the predetermined temperature, the low-temperature battery is regarded as the first battery and the SOH of the second battery is calculated; a program for calculating, for each of the second cells, the SOH of a first cell among the two or more first cells that has a small temperature difference from the second cell when the battery pack is in a powered state, using the SOC change amount and the SOH of the first cell.

16. A program applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and configured to detect a parameter for deterioration diagnosis, the program being executed by a control device (30) to calculate a state of health (SOH) indicating a degree of deterioration of each of the unit cells, The battery system is provided with a plurality of voltage sensors (24) for detecting terminal voltages of the individual cells, a first calculation process of acquiring the parameter detected by the detection unit for at least one of the plurality of unit cells and calculating the SOH based on the parameter; A second calculation process of calculating an amount of change in SOC caused by energization of the plurality of single cells; a third calculation process in which, when a cell among the plurality of cells for which the SOH has been calculated by the first calculation process is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell, the SOH of the second cell is calculated by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, by the SOH of the first cell; Equipped with In the first calculation process, at least two of the plurality of cells are set as first cells, the parameters detected by the detection unit are acquired, and the SOH is calculated based on the parameters; In the second calculation process, an SOC is calculated based on a detected voltage of the voltage sensor, and an amount of change in the SOC is calculated based on the SOC before and after a change caused by energization of the battery pack; In the third calculation process, a program is provided for combining, for each of the second cells, at least two of the first cells whose voltages are detected by the same voltage sensor, and calculating the SOH of the second cells using the SOC change amount and the SOH of the first cells.

17. A program applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and configured to detect a parameter for deterioration diagnosis, the program being executed by a control device (30) to calculate a state of health (SOH) indicating a degree of deterioration of each of the unit cells, In the battery system, the detection unit is provided in at least two of the plurality of unit cells, a first calculation process of acquiring the parameter detected by the detection unit for at least one of the plurality of unit cells and calculating the SOH based on the parameter; A second calculation process of calculating an amount of change in SOC caused by energization of the plurality of single cells; a third calculation process in which, when a cell among the plurality of cells for which the SOH has been calculated by the first calculation process is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell, the SOH of the second cell is calculated by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, by the SOH of the first cell; an abnormality determination process for determining whether or not an abnormality has occurred in the detection unit in the battery provided with the detection unit; Equipped with In the third calculation process, the program defines the single cell for which it is determined by the abnormality determination process that an abnormality has occurred in the detection unit as the second single cell, while defines the single cell for which the detection unit is provided and for which it is determined that no abnormality has occurred in the detection unit as the first single cell, and calculates the SOH of the second single cell.

18. A program applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and configured to detect a parameter for deterioration diagnosis, the program being executed by a control device (30) to calculate a state of health (SOH) indicating a degree of deterioration of each of the unit cells, a first calculation process of acquiring the parameter detected by the detection unit for at least one of the plurality of unit cells and calculating the SOH based on the parameter; A second calculation process of calculating an amount of change in SOC caused by energization of the plurality of single cells; a third calculation process in which, when a cell among the plurality of cells for which the SOH has been calculated by the first calculation process is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell, the SOH of the second cell is calculated by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, by the SOH of the first cell; a voltage determination process for determining whether or not the voltage of the battery cell is in a flat region in which the slope of the voltage with respect to the SOC is equal to or less than a predetermined value in a voltage-SOC characteristic line showing the relationship between the voltage of the battery cell and the SOC; Equipped with In the second calculation process, an SOC is calculated based on the voltage of the battery cell using the voltage-SOC characteristic line, and an amount of change in SOC is calculated based on the SOC before and after a change caused by energization of the battery pack; a program for not validating the calculation of the SOH of the second battery cell in the third calculation process when it is determined that the voltage of the battery cell is within the flat region;

19. A program applied to a battery system (10) including an assembled battery (20) in which a plurality of unit cells (21) are connected in series, and a detection unit (25, 26) provided in at least one of the plurality of unit cells and configured to detect a parameter for deterioration diagnosis, the program being executed by a control device (30) to calculate a state of health (SOH) indicating a degree of deterioration of each of the unit cells, a first calculation process of acquiring the parameter detected by the detection unit for at least one of the plurality of unit cells and calculating the SOH based on the parameter; A second calculation process of calculating an amount of change in SOC caused by energization of the plurality of single cells; a third calculation process in which, when a cell among the plurality of cells for which the SOH has been calculated by the first calculation process is defined as a first cell and a cell for which the SOH has not been calculated is defined as a second cell, the SOH of the second cell is calculated by multiplying a change rate, which is a ratio of an SOC change rate of the first cell to an SOC change rate of the second cell, by the SOH of the first cell; a change amount determination process for determining whether the SOC change amount calculated by the second calculation process is greater than a predetermined value; a fourth calculation process for calculating the SOH based on the SOC change amount and an integrated value of a current flowing through the battery cell within a period during which the SOC change amount was calculated, instead of the calculation of the SOH by the third calculation process, when the SOC change amount is determined to be greater than a predetermined value by the change amount determination process; A program that includes:

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