JP2016173260A - Battery deterioration determination device, battery pack, battery deterioration determination method and battery deterioration determination program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery deterioration determination device, a battery pack, a battery deterioration determination method and a battery deterioration determination program which facilitate recognition of a degradation state of a battery pack.SOLUTION: A correlation storage part 15 stores in advance a correlation between a resistance value for evaluation and a discharge capacity for evaluation. A measurement part 11 measures a voltage and a current supplied from a battery pack 2. A discharge capacity calculation part 12 and an apparent resistance value calculation part 13 respectively calculate, based on the measured voltage and current, a discharge capacity and a resistance value of the battery pack 2. An resistance value for evaluation acquisition part 14 acquires the resistance value for evaluation based on a relationship between the calculated discharge capacity and resistance value of the battery pack 2. An apparent discharge capacity acquisition part 16 acquires the discharge capacity for evaluation of the battery pack 2 based on the acquired resistance value for evaluation and the correlation stored in the correlation storage part 15.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a battery deterioration determination device, an assembled battery, a battery deterioration determination method, and a battery deterioration determination program.

  The assembled battery is a battery that can supply a large amount of power by connecting a large number of cells in series. The assembled battery is used for various things such as an electric vehicle (EV), a storage battery such as a solar power generation and a wind power generation such as a mega solar. For example, an assembled battery in an electric vehicle accumulates electricity by charging from a charging facility, and supplies electric power from the accumulated electricity to a motor that drives the vehicle.

  Electric vehicles (EVs) are being popularized because they have low environmental impact, high efficiency, and can use electricity from various energy sources. In recent years, infrastructure development such as general sales of electric vehicles and quick charging stations has begun. Also, from the viewpoint of environmental impact, mega solar and wind power generation facilities are expected to increase. Thus, the use of assembled batteries is steadily increasing due to the increase in various machines and facilities that use assembled batteries.

  However, when the assembled battery is used for a long time, for example, in the case of an electric vehicle, it is conceivable that the installed assembled battery deteriorates. In addition, it is conceivable that the performance change of the electric vehicle itself occurs due to deterioration of the assembled battery. In particular, the battery capacity of the assembled battery gradually deteriorates depending on the degree of use such as elapsed time and charge / discharge time, and the battery capacity decreases.

  Such deterioration of the assembled battery occurs not only in the electric vehicle but also in other devices using the assembled battery. Therefore, it is preferable to sequentially determine deterioration of the assembled battery according to the degree of use such as the passage of time.

  As a conventional technique for determining deterioration of an assembled battery, for example, a predetermined charge is performed with a certain amount of a first voltage in multi-stage charging, etc., charging is continued with a second voltage from the middle, and charging with a second voltage is performed. There has been proposed a technique for determining deterioration using the time taken for. In addition, a technique for determining deterioration of a battery based on a time during which constant current charging is performed has been proposed.

JP 2013-057603 A JP 2001-286064 A

  However, an assembled battery actually used in an electric vehicle or the like is difficult to remove from an attached device. For this reason, it is difficult to actually perform charging and discharging of the battery pack with constant current, which involves energy and time consumption.

  Similarly, it is difficult to sequentially determine the capacity of an assembled battery that is actually used by using a charging technique that determines battery deterioration based on the time taken for constant current charging. Furthermore, since the prior art using the first and second voltages is also constant current charging, it is difficult to sequentially determine the capacity of the assembled battery actually used.

  An object of the disclosed technology is to provide a battery deterioration determination device, an assembled battery, a battery deterioration determination method, and a battery deterioration determination program that make it easy to grasp the deterioration state of the battery pack.

  In one aspect of the battery deterioration determination device, the assembled battery, the battery deterioration determination method, and the battery deterioration determination program disclosed in the present application, the storage unit stores in advance a correlation between the evaluation resistance value and the evaluation discharge capacity. A measurement part measures the voltage and electric current which are supplied from an assembled battery with time passage. The calculation unit calculates a discharge capacity and a resistance value of the assembled battery based on the voltage and the current measured by the measurement unit. The evaluation resistance value acquisition unit acquires the evaluation resistance value based on the relationship between the discharge capacity and the resistance value of the assembled battery calculated by the calculation unit. The discharge capacity acquisition unit obtains the evaluation discharge capacity of the assembled battery based on the evaluation resistance value acquired by the evaluation resistance value acquisition unit and the correlation stored in the storage unit.

  According to one aspect of the battery deterioration determination device, the assembled battery, the battery deterioration determination method, and the battery deterioration determination program disclosed in the present application, the battery deterioration state can be easily grasped.

FIG. 1 is a block diagram of an electric vehicle equipped with a battery deterioration determination device according to an embodiment. FIG. 2A is a diagram illustrating a measurement result of the voltage of the assembled battery. FIG. 2B is a diagram illustrating a measurement result of the current of the assembled battery. FIG. 3 is a diagram illustrating the relationship between voltage and discharge capacity. FIG. 4 is a diagram illustrating the relationship between voltage and current for each discharge capacity. FIG. 5 is a diagram illustrating a discharge capacity curve corresponding to the traveling progress. FIG. 6 is a diagram illustrating the relationship between the number of days elapsed and the apparent discharge capacity. FIG. 7 is a diagram illustrating the correlation between the resistance value and the apparent discharge capacity. FIG. 8 is a diagram illustrating an example of a state in which valid data is extracted from the discharge capacity curve. FIG. 9 is a diagram for explaining the calculation of the apparent resistance value. FIG. 10 is a diagram for explaining the calculation of the apparent resistance value used for the evaluation of the discharge capacity. FIG. 11A is a diagram showing an approximate straight line when the discharge capacity classification for each 1 Ah of the electric vehicle A is used. FIG. 11B is a diagram illustrating an approximate straight line in the case of using the discharge capacity classification of 0.5 Ah of the electric vehicle A. FIG. 11C is a diagram illustrating an approximate straight line in the case of using the discharge capacity classification for every 2 Ah of the electric vehicle A. FIG. 12A is a diagram illustrating an approximate straight line when the discharge capacity classification for each 1 Ah of the electric vehicle B is used. FIG. 12B is a diagram illustrating an approximate straight line when the discharge capacity classification of 0.5 Ah of the electric vehicle B is used. FIG. 12C is a diagram illustrating an approximate straight line in the case of using the discharge capacity classification for every 2 Ah of the electric vehicle B. FIG. 13A is a diagram illustrating an approximate straight line when the discharge capacity classification for each 1 Ah of the electric vehicle C is used. FIG. 13B is a diagram illustrating an approximate straight line when the discharge capacity classification of 0.5 Ah of electric vehicle C is used. FIG. 13C is a diagram illustrating an approximate straight line in the case of using the discharge capacity classification for every 2 Ah of the electric vehicle C. FIG. 14A is a diagram illustrating an approximate straight line when data of all data sections of the electric vehicle A is used. FIG. 14B is a diagram illustrating an approximate straight line when data of a data section in the range of 0 to 10 Ah of electric vehicle A is used. FIG. 14C is a diagram illustrating an approximate straight line in a case where data in the data range of 0 to 20 Ah of electric vehicle A is used. FIG. 15A is a diagram illustrating an approximate straight line when data of all data sections of the electric vehicle B is used. FIG. 15B is a diagram illustrating an approximate straight line when data in the data section of electric vehicle B in the range of 0 to 10 Ah is used. FIG. 15C is a diagram illustrating an approximate straight line when data in the data section of electric vehicle B in the range of 0 to 20 Ah is used. FIG. 16A is a diagram illustrating an approximate line when data of all data sections of the electric vehicle C is used. FIG. 16B is a diagram illustrating an approximate straight line when data of a data section in the range of 0 to 10 Ah of the electric vehicle C is used. FIG. 16C is a diagram illustrating an approximate straight line when data in the data section in the range of 0 to 20 Ah of the electric vehicle C is used. FIG. 17 is a diagram for explaining acquisition of an apparent discharge capacity. FIG. 18 is a flowchart of calculation of an apparent discharge capacity by the battery deterioration determination device according to the example.

  Hereinafter, embodiments of a battery deterioration determination device, a battery pack, a battery deterioration determination method, and a battery deterioration determination program disclosed in the present application will be described in detail with reference to the drawings. In addition, the battery deterioration determination apparatus, the assembled battery, the battery deterioration determination method, and the battery deterioration determination program disclosed in the present application are not limited by the following embodiments.

  FIG. 1 is a block diagram of an electric vehicle equipped with a battery deterioration determination device according to an embodiment. Hereinafter, the battery deterioration determination device 1 mounted on the electric vehicle 100 as illustrated in FIG. 1 will be described as an example. However, the battery deterioration determination device 1 may be mounted on a mega solar battery, a storage battery, or the like.

  The electric vehicle 100 includes a battery deterioration determination device 1, an assembled battery 2, and a motor 3. The motor 3 is driven by electric power supplied from the assembled battery 2.

  The battery deterioration determination device 1 estimates the discharge capacity of the assembled battery 2 based on the electricity supplied from the assembled battery 2 to the motor 3 and determines the deterioration state of the assembled battery 2.

  The battery deterioration determination device 1 includes a measurement unit 11, a discharge capacity calculation unit 12, an apparent resistance value calculation unit 13, an evaluation resistance value acquisition unit 14, a correlation storage unit 15, an apparent discharge capacity acquisition unit 16, and a deterioration determination unit. 17 and a notification unit 18.

  The correlation storage unit 15 stores a correlation between the resistance value and the apparent discharge capacity. Specifically, the correlation storage unit 15 according to the present embodiment stores a correlation curve representing the correlation between the resistance value and the apparent discharge capacity. Here, the apparent discharge capacity is the discharge capacity of the assembled battery 2 at a predetermined voltage, and is a value that is a criterion for determining the deterioration state of the assembled battery 2. In the present embodiment, the discharge capacity at the inflection point at the end of discharge in the discharge capacity curve of the assembled battery 2 is set as the apparent discharge capacity. More specifically, in this embodiment, the discharge capacity corresponding to a voltage of 355 V is set as an apparent discharge capacity. The correlation storage unit 15 is an example of a “storage unit”.

  Here, calculation of the correlation curve between the resistance value and the apparent discharge capacity will be briefly described. There are various methods for obtaining the discharge capacity of the assembled battery 2.

  As a simple method, there is a method for obtaining a discharge capacity curve from measured values of current and voltage. Specifically, first, the assembled battery 2 is fully charged. Then, by discharging from the fully charged assembled battery 2 until the output stops at a constant current, a discharge capacity curve at the constant current can be obtained. And the discharge capacity corresponding to the voltage of 355V of the calculated | required discharge capacity curve turns into the apparent discharge capacity of the assembled battery 2 at the time. By obtaining this apparent discharge capacity according to the elapsed days of use of the electric vehicle 100, the apparent discharge capacity according to the deterioration of the assembled battery 2 can be acquired. Furthermore, the resistance value corresponding to each apparent discharge capacity can be calculated by obtaining the resistance value from the voltage and current values at the apparent discharge capacity. In this way, a correlation curve between the resistance value and the apparent discharge capacity can be obtained.

  However, it is difficult to discharge from the fully charged assembled battery 2 until the output stops at a constant current, for example, on the assembled battery 2 mounted in the electric vehicle 100. Therefore, in this embodiment, the apparent discharge capacity is calculated by the following method.

  First, the electric vehicle 100 runs all the way, i.e., until the electric person stops moving, and measures the voltage and current values of the assembled battery 2 during that time, so that each elapsed time as shown in FIGS. 2A and 2B. The voltage and current of the assembled battery 2 corresponding to the above are obtained. FIG. 2A is a diagram illustrating a measurement result of the voltage of the assembled battery. In FIG. 2A, the elapsed time is represented on the horizontal axis and the voltage is represented on the vertical axis. Moreover, FIG. 2B is a figure showing the measurement result of the electric current of an assembled battery. In FIG. 2B, the elapsed time is represented on the horizontal axis, and the current is represented on the vertical axis.

  Then, by integrating the measured current at each time point, the discharge capacity corresponding to the measured voltage at each time point is calculated. Then, the calculated discharge capacity and the measured voltage at each time point are associated with each other, and the horizontal axis represents the discharge capacity and the vertical axis represents the voltage, thereby plotting the graph 101 in FIG. . FIG. 3 is a diagram illustrating the relationship between voltage and discharge capacity. In FIG. 3, the horizontal axis represents discharge capacity, and the vertical axis represents voltage.

  However, in the graph 101, the measurement voltage fluctuates with respect to each discharge capacity due to regeneration or other conditions. Therefore, voltage correction is performed as follows. Specifically, the measured current and measured voltage values corresponding to a discharge capacity within a predetermined width from a specific discharge capacity are plotted in a coordinate system in which the horizontal axis represents current and the vertical axis represents voltage. In the present embodiment, the graph shown in FIG. 4 is obtained by obtaining an approximate straight line of the points plotted for each discharge capacity with a discharge capacity of ± 0.5 Ah from each of 10, 20, 30 and 40 Ah. The FIG. 4 is a diagram illustrating the relationship between voltage and current for each discharge capacity. In FIG. 4, the horizontal axis represents current and the vertical axis represents voltage. Each graph of FIG. 4 is a graph showing the relationship between current and voltage in discharge capacities of 10 ± 0.5 Ah, 20 ± 0.5 Ah, 30 ± 0.5 Ah, and 40 ± 0.5 Ah, respectively.

  And the resistance value corresponding to each discharge capacity is computable from each graph of FIG. Specifically, the slope of each graph in FIG. 4 is the resistance value. Then, the measured voltage is corrected using the calculated resistance value and the measured current, and the corrected result is plotted on the coordinate system of FIG. 3, thereby expressing the correspondence between the discharged capacity and the corrected voltage. A curve 102 is acquired. The calculation of the discharge capacity curve 102 is performed according to the traveling progress, and the discharge capacity curve 102 corresponding to the traveling progress is calculated. Thereby, as shown in FIG. 5, the discharge capacity curve according to the running progress is acquired. FIG. 5 is a diagram illustrating a discharge capacity curve corresponding to the traveling progress. In FIG. 5, the horizontal axis represents discharge capacity, and the vertical axis represents battery voltage. And in FIG. 5, the discharge capacity curve for every elapsed days which the electric vehicle 100 used is shown.

  Then, the discharge capacity at the inflection point at the end of discharge in each discharge capacity curve corresponding to the elapsed days is obtained as the apparent discharge capacity. In this embodiment, the discharge capacity corresponding to a voltage of 355 V is set as an apparent discharge capacity. That is, the discharge capacity cut off at 355 V is set as the apparent discharge capacity. A broken line 103 in FIG. 5 represents a value of 355V. More specifically, in this embodiment, a discharge capacity corresponding to a voltage of 355 ± 0.5 V in each discharge capacity curve is acquired, and an average of the acquired discharge capacity is obtained as an apparent discharge capacity.

  Here, the relationship between the apparent discharge capacity and the elapsed days is expressed as shown in FIG. FIG. 6 is a diagram illustrating the relationship between the number of days elapsed and the apparent discharge capacity. In FIG. 6, the horizontal axis represents the square root of the elapsed days, and the vertical axis represents the apparent discharge capacity. FIG. 6 shows the relationship between the elapsed days and the apparent discharge capacity in the four electric vehicles of the vehicles A to D. As for the vehicles A, C, and D, the relationship between the elapsed days and the apparent discharge capacity is approximately represented by a straight line descending to the right as shown by a solid line graph. Further, the vehicle B also approximately represents the relationship between the elapsed days and the apparent discharge capacity with a straight line descending to the right as shown by a broken line graph. As described above, the relationship between the elapsed days and the apparent discharge capacity varies, but in any case, as shown in FIG. 6, the apparent discharge capacity may decrease according to the elapsed days. I understand. Therefore, it can be determined how much the battery has deteriorated due to the apparent discharge capacity.

  Furthermore, using the measured current and the measured voltage, the resistance value at the discharge capacity of 0 Ah is calculated in the assembled battery 2 having each apparent discharge capacity. Therefore, the apparent discharge capacity is associated with the calculated resistance value, and plotted on a coordinate system in which the horizontal axis represents the apparent discharge capacity and the vertical axis represents the resistance value. Then, by obtaining an approximate straight line of the plotted points, the correlation between the resistance value shown by the graph 104 in FIG. 7 and the apparent discharge capacity is obtained. FIG. 7 is a diagram illustrating the correlation between the resistance value and the apparent discharge capacity. In FIG. 7, the horizontal axis represents the apparent discharge capacity, and the vertical axis represents the apparent resistance value.

  In the present embodiment, the correlation storage unit 15 stores a correlation curve between the resistance value indicated by the graph 104 and the apparent discharge capacity.

  Returning to FIG. 1, the description of the battery deterioration determination device 1 will be continued. The measuring unit 11 measures the electric current and voltage output from the assembled battery 2. Then, the measurement unit 11 outputs the measurement current to the discharge capacity calculation unit 12. Further, the measurement unit 11 outputs the measurement current and the measurement voltage to the apparent resistance value calculation unit 13.

  The discharge capacity calculation unit 12 receives measurement current input from the measurement unit 11. And the discharge capacity calculation part 12 calculates the discharge capacity at that time from the measurement current in a predetermined time. For example, the discharge capacity calculation unit 12 calculates the discharge capacity by integrating measurement currents for a predetermined time. Then, the discharge capacity calculation unit 12 outputs the calculated discharge capacity to the apparent resistance value calculation unit 13.

  The apparent resistance value calculation unit 13 receives the measurement current and the measurement voltage from the measurement unit 11. The apparent resistance value calculation unit 13 receives an input of the discharge capacity from the discharge capacity calculation unit 12. Then, the apparent resistance value calculation unit 13 acquires a discharge capacity curve on a coordinate system in which the horizontal axis represents the discharge capacity and the vertical axis represents the current from the relationship between the measured voltage and the discharge capacity. For example, the apparent resistance value calculation unit 13 plots the measurement voltage corresponding to the measurement current used when obtaining the discharge capacity at each time point on the coordinate system corresponding to the discharge capacity at each time point. Thus, a discharge capacity curve can be obtained. Then, the apparent resistance value calculation unit 13 has no regeneration (that is, the current is on the discharge side) in the data at each time point of the discharge capacity curve and reports the current increase (that is, at that time point compared to the current one second before). (If the value of is large). Hereinafter, the extracted data is referred to as “valid data”. For example, the effective data extracted from the discharge capacity curve by the apparent resistance value calculation unit 13 is shown by a graph 201 in FIG. 8, for example. FIG. 8 is a diagram illustrating an example of a state in which valid data is extracted from the discharge capacity curve. In FIG. 8, the horizontal axis represents the discharge capacity, and the vertical axis represents the voltage.

  Thus, in the present embodiment, only the data of no regeneration and current increase report is used for the calculation of the resistance value described below. In this respect, the charging characteristics and discharging characteristics of the assembled battery 2 are different. For this reason, when the data on the charging side is used for calculation of the resistance value, the data of different characteristics are mixed, making it difficult to calculate the resistance value. Therefore, in this embodiment, only the effective data described above is used for calculating an appropriate resistance value. However, the data on the charging side can be used for calculating the resistance value by correcting the characteristic between the discharging characteristic and the charging characteristic.

  Next, the apparent resistance value calculation unit 13 divides the effective data in a predetermined section of the change width of the discharge capacity indicated by the section 202 in FIG. 8, and specifies the effective data in each section. In FIG. 8, the section 202 divides valid data with a width of 10 Ah.

  Then, the apparent resistance value calculation unit 13 plots the measurement current and the measurement voltage corresponding to the effective data for each section as shown in FIG. 9 on the coordinate system in which the horizontal axis represents current and the vertical axis represents voltage. To do. FIG. 9 is a diagram for explaining the calculation of the apparent resistance value. In FIG. 9, the horizontal axis represents current and the vertical axis represents voltage. Next, the apparent resistance value calculation unit 13 obtains an approximate straight line of the plotted points as indicated by a straight line 203, for example. Then, the apparent resistance value calculation unit 13 acquires the slope of the approximate curve as the apparent resistance value in each section. The apparent resistance value is a resistance value of the assembled battery 2 estimated from the measurement current and the measurement voltage.

  Here, the discharge capacity classification (the fineness of the section for data division) is every 10 Ah. However, since the number of apparent resistance values to be calculated increases as the division of the discharge capacity to be divided becomes finer, the apparent resistance value calculation unit 13 reduces the accuracy of the approximate straight line by making the division of data division finer. Can be improved.

  The apparent resistance value calculation unit 13 outputs the apparent resistance value in the predetermined section of each discharge capacity to the evaluation resistance value acquisition unit 14. The discharge capacity calculation unit 12 and the apparent resistance value calculation unit 13 correspond to an example of a “calculation unit”.

  The evaluation resistance value acquisition unit 14 receives an input of an apparent resistance value for each predetermined section from the apparent resistance value calculation unit 13. Next, the evaluation resistance value acquisition unit 14 represents the discharge capacity on the horizontal axis, the resistance value on the vertical axis, and a coordinate system in which the origin value is 0, depending on the discharge capacity for each predetermined section. Plot the apparent resistance. Next, the evaluation resistance value acquiring unit 14 obtains an approximate straight line of the plotted points. For example, the evaluation resistance value acquisition unit 14 performs linear approximation of each point using a minimum approximation method or the like to obtain an approximate line 204 as shown in FIG. FIG. 10 is a diagram for explaining the calculation of the apparent resistance value used for the evaluation of the discharge capacity. In FIG. 10, the horizontal axis represents the discharge capacity, and the vertical axis represents the apparent resistance value.

  Here, in FIG. 10, a section for each 1 Ah is used as a section for the discharge capacity. FIG. 10 shows a state in which an approximate straight line is obtained using the discharge capacity and resistance value data until the voltage decreases and the data variation increases. In the following, a data interval from when the voltage decreases to when the data variation increases is referred to as an “all data interval”.

  Then, the evaluation resistance value acquisition unit 14 acquires the resistance value at the intercept 205 with the vertical axis of the approximate line 204, that is, the apparent resistance value in the fully charged state. In other words, the evaluation resistance value acquisition unit 14 acquires a resistance value having a discharge capacity of 0 Ah, that is, SOC (State Of Charge) 100%, as an apparent resistance value in a fully charged state. The apparent resistance value in the fully charged state corresponds to an example of “evaluation resistance value”.

  Thereafter, the evaluation resistance value acquisition unit 14 outputs the apparent resistance value in the fully charged state to the apparent discharge capacity acquisition unit 16.

  However, since the number of apparent resistance values to be calculated increases as the discharge capacity classification is made finer, the apparent resistance value calculation unit 13 improves the accuracy of the approximate line by finely dividing the section. be able to. Moreover, even if only the discharge capacity and resistance value data in the section where the discharge capacity is low are used, the evaluation resistance value acquisition unit 14 generates an approximate straight line 204 that is almost the same as when the points up to the case where the discharge capacity is large are used. Can be sought. Hereinafter, the influence of the discharge capacity classification and the influence of the data section will be described. Here, the case where data is collected using three electric vehicles A to C will be described.

  FIG. 11A is a diagram showing an approximate straight line when the discharge capacity classification for each 1 Ah of the electric vehicle A is used. FIG. 11B is a diagram illustrating an approximate straight line in the case of using the discharge capacity classification of 0.5 Ah of the electric vehicle A. FIG. 11C is a diagram illustrating an approximate straight line in the case of using the discharge capacity classification for every 2 Ah of the electric vehicle A. FIG. 12A is a diagram illustrating an approximate straight line when the discharge capacity classification for each 1 Ah of the electric vehicle B is used. FIG. 12B is a diagram illustrating an approximate straight line when the discharge capacity classification of 0.5 Ah of the electric vehicle B is used. FIG. 12C is a diagram illustrating an approximate straight line in the case of using the discharge capacity classification for every 2 Ah of the electric vehicle B. FIG. 13A is a diagram illustrating an approximate straight line when the discharge capacity classification for each 1 Ah of the electric vehicle C is used. FIG. 13B is a diagram illustrating an approximate straight line when the discharge capacity classification of 0.5 Ah of electric vehicle C is used. FIG. 13C is a diagram illustrating an approximate straight line in the case of using the discharge capacity classification for every 2 Ah of the electric vehicle C. In each of FIGS. 11A to 13C, the vertical axis represents the resistance value, and the horizontal axis represents the discharge capacity.

  The apparent resistance value data in the case of using the discharge capacity classification for each 1 Ah in the electric vehicle A is represented by the points shown in FIG. 11A. Then, the apparent resistance value in the fully charged state of the electric vehicle A obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 11A is 0.0894. Further, the apparent resistance value data in the case of using the discharge capacity classification for each 0.5 Ah in the electric vehicle A is represented by the points shown in FIG. 11B. Then, the apparent resistance value in the fully charged state of the electric vehicle A obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 11B is 0.0906. Moreover, the data of the apparent resistance value in the case of using the discharge capacity classification for every 2 Ah in the electric vehicle A is represented by the points shown in FIG. 11C. Then, the apparent resistance value in the fully charged state of the electric vehicle A obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 11C is 0.0924. Thus, when the apparent resistance value in the fully charged state of the electric vehicle A is obtained, a value that does not substantially change even if the discharge capacity classification is changed is calculated.

  The apparent resistance value data in the case of using the discharge capacity classification for each 1 Ah in the electric vehicle B is represented by the points shown in FIG. 12A. Then, the apparent resistance value in the fully charged state of the electric vehicle B obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 12A is 0.1245. Moreover, the data of the apparent resistance value in the case of using the discharge capacity classification for every 0.5 Ah in the electric vehicle B is represented by the points shown in FIG. 12B. Then, the apparent resistance value in the fully charged state of the electric vehicle B obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 12B is 0.1227. Further, the apparent resistance value data in the case of using the discharge capacity classification for every 2 Ah in the electric vehicle B is represented by the points shown in FIG. 12C. Then, the apparent resistance value in the fully charged state of the electric vehicle B obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 12C is 0.1219. Thus, when the apparent resistance value in the fully charged state of the electric vehicle B is obtained, a value that does not change substantially even if the discharge capacity classification is changed is calculated.

  The apparent resistance value data in the case of using the discharge capacity classification for each 1 Ah in the electric vehicle C is represented by the points shown in FIG. 13A. Then, the apparent resistance value in the fully charged state of the electric vehicle C obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 13A is 0.1201. Further, the apparent resistance value data in the case of using the discharge capacity classification for every 0.5 Ah in the electric vehicle C is represented by the points shown in FIG. 13B. Then, the apparent resistance value in the fully charged state of the electric vehicle C obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 13B is 0.1204. Further, the apparent resistance value data in the case of using the discharge capacity classification for every 2 Ah in the electric vehicle C is represented by the points shown in FIG. 13C. Then, the apparent resistance value in the fully charged state of the electric vehicle C obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 13C is 0.1217. Thus, when the apparent resistance value in the fully charged state of the electric vehicle C is obtained, a value that does not change substantially even if the discharge capacity classification is changed is calculated.

  Thus, in any of the electric vehicles A to C, an equivalent apparent resistance value can be calculated regardless of the category of the discharge capacity. Therefore, in the calculation of the apparent resistance value, it is possible to use a discharge capacity category that is easy to use.

  FIG. 14A is a diagram illustrating an approximate straight line when data of all data sections of the electric vehicle A is used. FIG. 14B is a diagram illustrating an approximate straight line when data of a data section in the range of 0 to 10 Ah of electric vehicle A is used. FIG. 14C is a diagram illustrating an approximate straight line in a case where data in the data range of 0 to 20 Ah of electric vehicle A is used. FIG. 15A is a diagram illustrating an approximate straight line when data of all data sections of the electric vehicle B is used. FIG. 15B is a diagram illustrating an approximate straight line when data in the data section of electric vehicle B in the range of 0 to 10 Ah is used. FIG. 15C is a diagram illustrating an approximate straight line when data in the data section of electric vehicle B in the range of 0 to 20 Ah is used. FIG. 16A is a diagram illustrating an approximate line when data of all data sections of the electric vehicle C is used. FIG. 16B is a diagram illustrating an approximate straight line when data of a data section in the range of 0 to 10 Ah of the electric vehicle C is used. FIG. 16C is a diagram illustrating an approximate straight line when data in the data section in the range of 0 to 20 Ah of the electric vehicle C is used. In each of FIGS. 14A to 16C, the vertical axis represents the resistance value, and the horizontal axis represents the discharge capacity.

  The apparent resistance value data in the entire data section in the electric vehicle A is represented by the points shown in FIG. 14A. Then, the apparent resistance value in the fully charged state of the electric vehicle A obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 14A is 0.0894. Further, the apparent resistance value data in the data section in the range of 0 to 10 Ah in the electric vehicle A is represented by the points shown in FIG. 14B. Then, the apparent resistance value in the fully charged state of the electric vehicle A obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 14B is 0.0887. Further, the apparent resistance value data in the data section in the range of 0 to 20 Ah in the electric vehicle A is represented by the points shown in FIG. 14C. Then, the apparent resistance value in the fully charged state of the electric vehicle A obtained from the approximate straight line 204 of the points indicating the resistance values in FIG. 14C is 0.0944. Thus, when the apparent resistance value in the fully charged state of the electric vehicle A is obtained, a value that does not change substantially even if the data section is changed is calculated.

  The apparent resistance value data of the entire data section in the electric vehicle B is represented by the points shown in FIG. 15A. Then, the apparent resistance value in the fully charged state of the electric vehicle B obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 15A is 0.1245. Further, the apparent resistance value data in the data section in the range of 0 to 10 Ah in the electric vehicle B is represented by the points shown in FIG. 15B. Then, the apparent resistance value in the fully charged state of the electric vehicle B obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 15B is 0.1224. Further, the apparent resistance value data in the data section in the range of 0 to 20 Ah in the electric vehicle B is represented by the points shown in FIG. 15C. Then, the apparent resistance value in the fully charged state of the electric vehicle B obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 15C is 0.1219. Thus, when the apparent resistance value in the fully charged state of the electric vehicle B is obtained, a value that does not change substantially even if the data section is changed is calculated.

  The apparent resistance value data in the entire data section in the electric vehicle C is represented by the points shown in FIG. 16A. Then, the apparent resistance value in the fully charged state of the electric vehicle C obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 16A is 0.1201. Moreover, the apparent resistance value data in the data section in the range of 0 to 10 Ah in the electric vehicle C is represented by the points shown in FIG. 16B. Then, the apparent resistance value in the fully charged state of the electric vehicle C obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 16B is 0.1222. Moreover, the apparent resistance value data in the data section in the range of 0 to 20 Ah in the electric vehicle C is represented by the points shown in FIG. 16C. Then, the apparent resistance value in the fully charged state of the electric vehicle C obtained from the approximate straight line 204 of the point indicating the apparent resistance value in FIG. 16C is 0.1190. Thus, when the apparent resistance value in the fully charged state of the electric vehicle C is obtained, a value that does not change substantially even if the data section is changed is calculated.

  As described above, almost the same approximate curve 204 can be obtained regardless of the data section to be used. Therefore, the evaluation resistance value acquisition unit 14 can calculate the apparent resistance value in the fully charged state using only the discharge capacity and the resistance value collected in a short time after the electric vehicle 100 starts running. However, since the temperature of the assembled battery 2 is not stable immediately after starting running, the values of the measured current and the measured voltage may be different from those of the assembled battery 2 after the temperature is stabilized. Therefore, the evaluation resistance value acquiring unit 14 may obtain the approximate straight line 204 using the discharge capacity and the resistance value for a predetermined period thereafter except for a certain period immediately after starting.

  Returning to FIG. 1, the description will be continued. The apparent discharge capacity acquisition unit 16 receives an input of the apparent resistance value in the fully charged state from the evaluation resistance value acquisition unit 14. Then, the apparent discharge capacity acquisition unit 16 acquires the apparent discharge capacity corresponding to the apparent resistance value in the fully charged state, as shown in FIG. 17, using the correlation curve held by the correlation storage unit 15. To do. FIG. 17 is a diagram for explaining acquisition of an apparent discharge capacity. In FIG. 17, the horizontal axis represents the apparent discharge capacity, and the vertical axis represents the apparent resistance value. For example, when the apparent discharge capacity acquisition unit 16 receives the resistance value 207 as an apparent resistance value at full charge, the apparent discharge capacity acquisition unit 16 acquires the discharge capacity 208 as an apparent discharge capacity from the correlation curve.

  Thereafter, the apparent discharge capacity acquisition unit 16 outputs the acquired apparent discharge capacity to the deterioration determination unit 17. Here, in this embodiment, in order to determine the deterioration state of the assembled battery 2, the discharge capacity corresponding to the apparent resistance value in the fully charged state is obtained. This is because the resistance value at 0 Ah is considered to be the closest to the actual resistance value, and the discharge capacity corresponding to the resistance value is considered to be an ideal discharge capacity. Therefore, the deterioration state of the assembled battery 2 can be determined more appropriately by using the discharge capacity corresponding to the apparent resistance value in the fully charged state. However, the discharge capacity of the apparent resistance value used for the judgment criterion can also take other values, and if the value of the discharge capacity when obtaining the apparent resistance value used for the creation of the correlation curve and the evaluation matches, Other discharge capacities can also be used as evaluation criteria. This apparent discharge capacity acquisition unit 16 is an example of a “discharge capacity acquisition unit”. The discharge capacity corresponding to the apparent resistance value in the fully charged state corresponds to an example of “evaluation discharge capacity”.

  The deterioration determination unit 17 receives an input of the apparent discharge capacity from the apparent discharge capacity acquisition unit 16. Here, the deterioration determination unit 17 stores in advance a discharge capacity threshold that is a determination criterion for deterioration of the assembled battery 2. And the deterioration determination part 17 determines whether the received apparent discharge capacity is more than a discharge capacity threshold value. When the received discharge capacity is equal to or greater than the discharge capacity threshold, the deterioration determination unit 17 determines that the assembled battery 2 has not deteriorated, and ends the process.

  On the other hand, when the received apparent discharge capacity is less than the discharge capacity threshold, the deterioration determination unit 17 determines that the assembled battery 2 is deteriorated and notifies the notification unit 18 of the deterioration of the assembled battery 2.

  The notification unit 18 receives a notification of deterioration of the assembled battery 2 from the deterioration determination unit 17. And the alerting | reporting part 18 notifies the user of an electric vehicle of deterioration of the assembled battery 2. FIG.

  Here, in this embodiment, degradation is determined using a threshold value and notified to the user, but the information notified to the user is not limited to this. For example, the notification unit 18 may be configured to notify the user of the apparent discharge capacity obtained by the apparent discharge capacity acquisition unit 16. In that case, the user refers to the notified apparent discharge capacity to determine the deterioration state of the assembled battery 2.

  Next, the flow of calculation of the apparent discharge capacity by the battery deterioration determination device according to the present embodiment will be described with reference to FIG. FIG. 18 is a flowchart of calculation of an apparent discharge capacity by the battery deterioration determination device according to the example.

  The measurement part 11 measures the electric current and voltage of the assembled battery 2 (step S1). Then, the measurement unit 11 outputs the measurement current to the discharge capacity calculation unit 12. Further, the measurement unit 11 outputs the measurement current and the measurement voltage to the apparent resistance value calculation unit 13.

  The discharge capacity calculation unit 12 receives measurement current input from the measurement unit 11. The discharge capacity calculation unit 12 integrates the measurement current received from the measurement unit 11 and calculates the discharge capacity at each time point. Then, the discharge capacity calculation unit 12 outputs the calculated discharge capacity at each time point to the apparent resistance value calculation unit 13. The apparent resistance value calculation unit 13 receives the measurement current and the measurement voltage from the measurement unit 11. The apparent resistance value calculation unit 13 receives an input of the discharge capacity from the discharge capacity calculation unit 12. And the apparent resistance value calculation part 13 calculates | requires a discharge capacity curve from the acquired measured current, measured voltage, and discharge capacity (step S2).

  Next, the apparent resistance value calculation unit 13 extracts valid data from the discharge capacity curve (step S3).

  Next, the apparent resistance value calculation unit 13 divides the extracted effective data by a predetermined section of the change width of the discharge capacity (step S4).

  Next, the apparent resistance value calculation unit 13 plots the measurement current and the measurement voltage corresponding to the valid data for each section on a coordinate system in which the horizontal axis represents current and the vertical axis represents voltage. Next, the apparent resistance value calculation unit 13 obtains an approximate straight line of the plotted points. Then, the apparent resistance value calculation unit 13 acquires the slope of the approximate curve as the apparent resistance value in each section (step S5). Thereafter, the apparent resistance value calculation unit 13 outputs the obtained apparent resistance value to the evaluation resistance value acquisition unit 14.

  The evaluation resistance value acquisition unit 14 receives an input of an apparent resistance value from the apparent resistance value calculation unit 13. Next, the evaluation resistance value acquisition unit 14 represents the discharge capacity on the horizontal axis, the resistance value on the vertical axis, and a coordinate system in which the origin value is 0, depending on the discharge capacity for each predetermined section. Plot the apparent resistance. Next, the evaluation resistance value acquiring unit 14 obtains an approximate straight line of the plotted points. Then, the evaluation resistance value acquisition unit 14 acquires the resistance value of the intercept with the vertical axis of the approximate line as the apparent resistance value in the fully charged state (step S6). Thereafter, the evaluation resistance value acquisition unit 14 outputs the apparent resistance value in the fully charged state to the apparent discharge capacity acquisition unit 16.

  The apparent discharge capacity acquisition unit 16 receives an input of the apparent resistance value in the fully charged state from the evaluation resistance value acquisition unit 14. Then, the apparent discharge capacity acquisition unit 16 acquires the apparent discharge capacity corresponding to the apparent resistance value in the fully charged state from the correlation curve held by the correlation storage unit 15 (step S7).

  The battery deterioration determination device 1 described above can be realized by, for example, a computer having a current and voltage measuring device, a CPU (Central Processing Unit), and a memory. The measuring instrument realizes the function of the measuring unit 11.

  The memory implements the function of the correlation storage unit 15. Further, for example, the memory includes a discharge capacity calculation unit 12, an apparent resistance value calculation unit 13, an evaluation resistance value acquisition unit 14, an apparent discharge capacity acquisition unit 16, a deterioration determination unit 17, and a notification unit 18 illustrated in FIG. Various programs including a program for realizing the function are stored.

  The CPU reads and executes various programs stored in the memory to thereby execute a discharge capacity calculation unit 12, an apparent resistance value calculation unit 13, an evaluation resistance value acquisition unit 14, an apparent discharge capacity acquisition unit 16, and a deterioration determination unit. 17 and the notification unit 18 are realized.

  As described above, the battery deterioration determination device according to the present embodiment estimates the resistance value at that time from the voltage and current of the assembled battery in use, and at that time based on the estimated resistance value. The discharge capacity of the assembled battery is estimated. Thereby, the discharge capacity of the assembled battery in use can be estimated, and the deterioration state of the assembled battery can be easily determined.

  In addition, since the battery deterioration determination device according to the present embodiment can estimate the discharge capacity by measuring in a short time, the discharge capacity can be estimated without using the assembled battery for a long time, and the deterioration state of the assembled battery can be more easily performed. Can be determined.

DESCRIPTION OF SYMBOLS 1 Battery deterioration determination apparatus 2 Assembly battery 3 Motor 11 Measurement part 12 Discharge capacity calculation part 13 Apparent resistance value calculation part 14 Resistance value acquisition part 15 Evaluation storage part 16 Apparent discharge capacity acquisition part 17 Deterioration determination part 18 Notification Part

Claims (9)

A storage unit that stores in advance the correlation between the evaluation resistance value and the evaluation discharge capacity;
A measurement unit that measures the voltage and current supplied from the battery pack over time;
Based on the voltage and the current measured by the measurement unit, a calculation unit that calculates a discharge capacity and a resistance value of the assembled battery;
An evaluation resistance value acquisition unit that acquires the evaluation resistance value based on the relationship between the discharge capacity and the resistance value of the assembled battery calculated by the calculation unit;
A discharge capacity acquisition unit for obtaining the evaluation discharge capacity of the assembled battery based on the evaluation resistance value acquired by the evaluation resistance value acquisition unit and the correlation stored in the storage unit; A battery deterioration determination device characterized by that.   The battery deterioration determination device according to claim 1, wherein the calculation unit calculates a discharge capacity and a resistance value of the assembled battery based on a voltage and a current when the assembled battery is discharged.   The evaluation resistance value acquisition unit calculates the evaluation resistance value based on a discharge capacity and a resistance value of the assembled battery near a discharge start of the assembled battery. The battery deterioration determination device described.   The evaluation resistance value acquisition unit represents a point of a set of the discharge capacity and the resistance value of the assembled battery on a graph in which the horizontal axis represents the discharge capacity and the vertical axis represents the resistance value. The battery deterioration determination device according to claim 1, wherein an intercept of the obtained approximate curve with a vertical axis is acquired as the evaluation resistance value.   5. The battery deterioration determination device according to claim 1, wherein the evaluation resistance value acquisition unit acquires a resistance value corresponding to a discharge capacity of 0 Ah as the evaluation resistance value. 6.   The battery deterioration determination device according to claim 1, wherein the evaluation discharge capacity is a discharge capacity of the assembled battery at an inflection point at the end of discharge. A plurality of batteries in one set;
A storage unit that stores in advance the correlation between the evaluation resistance value and the evaluation discharge capacity;
A measuring unit that measures the voltage and current supplied from the set of batteries according to the passage of time;
Based on the voltage and the current measured by the measurement unit, a calculation unit that calculates a discharge capacity and a resistance value of the set of the plurality of batteries;
An evaluation resistance value acquisition unit that acquires the evaluation resistance value based on the relationship between the discharge capacity and the resistance value of the assembled battery calculated by the calculation unit;
Based on the evaluation resistance value acquired by the evaluation resistance value acquisition unit and the correlation stored in the storage unit, the discharge capacity acquisition for obtaining the evaluation discharge capacity of the plurality of batteries of the set. And a battery pack. Measure the voltage and current supplied from the battery pack over time,
Based on the measured voltage and current, calculate the discharge capacity and resistance value of the assembled battery,
Obtain an evaluation resistance value based on the relationship between the calculated discharge capacity and resistance value of the assembled battery,
A battery deterioration determination method, wherein the evaluation discharge capacity of the assembled battery is obtained from the acquired evaluation resistance value based on a correlation between the evaluation resistance value and the evaluation discharge capacity that is previously held. Measure the voltage and current supplied from the battery pack over time,
Based on the measured voltage and current, calculate the discharge capacity and resistance value of the assembled battery,
Obtain an evaluation resistance value based on the relationship between the calculated discharge capacity and resistance value of the assembled battery,
Based on the correlation between the evaluation resistance value and the evaluation discharge capacity that is previously held, the computer is caused to execute a process for obtaining the evaluation discharge capacity of the assembled battery from the acquired evaluation resistance value. Battery deterioration judgment program.

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