Battery self-discharge detection method and device, electronic equipment and storage medium

Abstract

The invention provides a battery self-discharge detection method and apparatus, an electronic device and a storage medium. The method comprises the steps of obtaining an initial open-circuit voltage and an initial cell temperature of a to-be-detected battery; charging or discharging the to-be-tested battery with a preset current for a preset duration; after standing for a set time period, measuring the open-circuit voltage and the cell temperature of the to-be-measured battery, and returning to execute the steps: charging or discharging the to-be-measured battery with a preset current for a preset duration until the number of times of returning to execute the steps is not less than two to obtain at least three groups of charging and discharging data of the to-be-measured battery, and based on the initial open-circuit voltage, the initial cell temperature and the charging and discharging data of the at least three groups of to-be-measured batteries, obtaining the cell temperature coefficient, the voltage capacity ratio and the self-discharging current of the to-be-measured batteries through a numerical solution. The battery self-discharge detection method does not need to be placed for several days or weeks, the battery self-discharge detection time can be shortened, the battery cell temperature coefficient and the voltage capacity ratio of the to-be-detected battery are considered, and the obtained self-discharge current is more accurate.

Description

Technical Field

[0001] The present application relates to the field of battery detection technology, and in particular to a battery self-discharge detection method, device, electronic device and storage medium. Background Art

[0002] Battery self-discharge refers to the phenomenon of spontaneous loss of battery capacity when the battery is in an open circuit state. It is one of the main parameters for measuring battery performance. Battery self-discharge performance is extremely important for safety and battery life.

[0003] Due to the problem of manufacturing process, self-discharge cannot be eliminated in the actual application of batteries. Excessive self-discharge of a single battery often causes its own voltage to drop rapidly, which in turn weakens the charge retention ability of the entire power battery pack. Therefore, it is very important to detect battery self-discharge. There are many reasons for self-discharge, mainly self-discharge caused by internal micro-short circuits and attenuation of the positive and negative redox capacity of the electrolyte.

[0004] Currently, the self-discharge performance of a battery is tested by detecting the voltage drop of the battery (i.e., the K value method). During the test, it takes several days or weeks to obtain a sufficiently large voltage drop. This test method often consumes a lot of time. Therefore, how to detect the self-discharge performance of a battery in a short time is an important issue that needs to be solved. Summary of the invention

[0005] The present application provides a battery self-discharge detection method, device, electronic device and storage medium to shorten the battery self-discharge detection time and obtain a more accurate self-discharge current. The specific technical solution is as follows:

[0006] In a first aspect, the present application provides a battery self-discharge detection method, the method comprising:

[0007] Obtain the initial open circuit voltage V0 and initial cell temperature T0 of the battery to be tested;

[0008] Charging or discharging the battery to be tested with a preset current and for a preset time;

[0009] After standing for a set period of time, measuring the open circuit voltage and the cell temperature of the battery to be tested, and returning to the execution step: charging or discharging the battery to be tested with a preset current for a preset time, until the number of times of returning to the execution step is not less than twice, and at least three sets of charge and discharge data of the battery to be tested are obtained, wherein each time the step of charging or discharging the battery to be tested with a preset current for a preset time is returned, at least one of the preset current and the preset time is different, and the charge and discharge data includes: the preset current, the preset time, the open circuit voltage and the cell temperature;

[0010] Based on the initial open circuit voltage V0, the initial battery cell temperature T0 and the charge and discharge data of the at least three groups of the batteries to be tested, the battery cell temperature coefficient, voltage-to-capacity ratio and self-discharge current of the battery to be tested are obtained by numerical solution, wherein the self-discharge current is used to characterize the self-discharge characteristics of the battery to be tested.

[0011] In a possible design, when the number of times the execution step is returned is twice, three sets of the charge and discharge data are obtained, and the charge and discharge data include: a first preset current I1, a first preset time t1, a first open circuit voltage V1, a first battery cell temperature T1, a second preset current I2, a second preset time t2, a second open circuit voltage V2, a second battery cell temperature T2, a third preset current I3, a third preset time t3, a third open circuit voltage V3, and a third battery cell temperature T3;

[0012] The method of obtaining the cell temperature coefficient, voltage-to-capacity ratio and self-discharge current of the battery to be tested by a numerical solution based on the initial open circuit voltage V0, the initial cell temperature T0 and the at least three groups of charge and discharge data of the battery to be tested comprises:

[0013] Based on the initial open circuit voltage V0, the initial battery cell temperature T0, the first preset current I1, the first preset time t1, the first open circuit voltage V1, the first battery cell temperature T1, the second preset current I2, the second preset time t2, the second open circuit voltage V2, the second battery cell temperature T2, the third preset current I3, the third preset time t3, the third open circuit voltage V3, and the third battery cell temperature T3;

[0014] Use the formula: Q1=I1*t1+Isd*t1, Q2=I2*t2+Isd*t2, Q3=I3*t3+Isd*t3, V11=V1+C*(T1-T0), V22=V2+ C*(T2-T0), V33=V3+C*(T3-T0), ΔV1=V11-V0, ΔV2=V22-V11, ΔV3=V33-V22, dV / dQ=ΔV1 / Q1, dV / dQ=ΔV2 / Q2, dV / dQ=ΔV3 / Q3, wherein Q1 is the first charge, Q2 is the second charge, Q3 is the third charge, V11 is the first actual voltage, ΔV1 is the first voltage difference, V22 is the second actual voltage, ΔV2 is the second voltage difference, V33 is the third actual voltage, ΔV3 is the third voltage difference, Isd is the self-discharge current, dV / dQ is the voltage-to-capacity ratio, and C is the battery cell temperature coefficient of the battery;

[0015] The cell temperature coefficient C, voltage-to-capacity ratio dV / dQ and self-discharge current Isd of the battery to be tested are obtained by numerical solution.

[0016] In a possible design, when the number of times the step of returning to execute is greater than two times, at least three sets of the charge and discharge data are obtained;

[0017] The method of obtaining the cell temperature coefficient, voltage-to-capacity ratio and self-discharge current of the battery to be tested by a numerical solution based on the initial open circuit voltage V0, the initial cell temperature T0 and the at least three groups of charge and discharge data of the battery to be tested comprises:

[0018] Based on the initial open circuit voltage V0, the initial cell temperature T0 and the at least three groups of charge and discharge data of the battery to be tested, the cell temperature coefficient C, the voltage-to-capacity ratio dV / dQ and the self-discharge current Isd of the battery to be tested are obtained by numerical solution using the least squares method.

[0019] In a possible design, when the preset current is a variable current, the product of the preset current and the preset time length is equal to the integral of the preset current and the preset time length.

[0020] In a possible design, charging or discharging the battery to be tested with a preset current for a preset time period includes:

[0021] By connecting different resistors to the battery to be tested, the battery to be tested is discharged with a preset current for a preset time;

[0022] The battery to be tested is charged with a preset current for a preset time by connecting an external charging device to the battery to be tested.

[0023] In a second aspect, the present application provides a battery self-discharge detection device, the device comprising:

[0024] An acquisition module is used to obtain the initial open circuit voltage V0 and the initial cell temperature T0 of the battery to be tested;

[0025] A charging and discharging module, used for charging or discharging the battery to be tested with a preset current and for a preset time;

[0026] A measuring module, configured to measure the open circuit voltage and the cell temperature of the battery to be tested after standing for a set period of time, and return to the execution step: charging or discharging the battery to be tested with a preset current for a preset time, until the number of times of returning to the execution step is not less than twice, and at least three groups of charge and discharge data of the battery to be tested are obtained, wherein each time the execution step is returned: charging or discharging the battery to be tested with a preset current for a preset time, at least one of the preset current and the preset time is different, and the charge and discharge data includes: the preset current, the preset time, the open circuit voltage and the cell temperature;

[0027] A calculation module is used to obtain the cell temperature coefficient, voltage-to-capacity ratio and self-discharge current of the battery to be tested through a numerical solution based on the initial open circuit voltage V0, the initial cell temperature T0 and the at least three groups of charge and discharge data of the battery to be tested, wherein the self-discharge current is used to characterize the self-discharge characteristics of the battery to be tested.

[0028] In a possible design, when the number of times the execution step is returned is twice, three sets of the charge and discharge data are obtained, and the charge and discharge data include: a first preset current I1, a first preset time t1, a first open circuit voltage V1, a first battery cell temperature T1, a second preset current I2, a second preset time t2, a second open circuit voltage V2, a second battery cell temperature T2, a third preset current I3, a third preset time t3, a third open circuit voltage V3, and a third battery cell temperature T3;

[0029] The calculation module is specifically used based on the initial open circuit voltage V0, the initial battery cell temperature T0, the first preset current I1, the first preset time t1, the first open circuit voltage V1, the first battery cell temperature T1, the second preset current I2, the second preset time t2, the second open circuit voltage V2, the second battery cell temperature T2, the third preset current I3, the third preset time t3, the third open circuit voltage V3, and the third battery cell temperature T3; using the formula: Q1=I1*t1+Isd*t1, Q2=I2*t2+Isd*t2, Q3=I3*t3+Isd*t3, V11=V1+C*(T1-T0), V22=V2+C*(T2-T0), V33=V3+C*(T3-T0), Δ V1=V11-V0, ΔV2=V22-V11, ΔV3=V33-V22, dV / dQ=ΔV1 / Q1, dV / dQ=ΔV2 / Q2, dV / dQ=ΔV3 / Q3, wherein Q1 is the first charge, Q2 is the second charge, Q3 is the third charge, V11 is the first actual voltage, ΔV1 is the first voltage difference, V22 is the second actual voltage, ΔV2 is the second voltage difference, V33 is the third actual voltage, ΔV3 is the third voltage difference, Isd is the self-discharge current, dV / dQ is the voltage-to-capacity ratio, and C is the battery cell temperature coefficient of the battery; the battery cell temperature coefficient C, the voltage-to-capacity ratio dV / dQ and the self-discharge current Isd of the battery to be tested are obtained by numerical solution.

[0030] In a possible design, when the number of times the step of returning to execute is greater than two times, at least three sets of the charge and discharge data are obtained;

[0031] The calculation module is specifically used to obtain the cell temperature coefficient C, voltage-to-capacity ratio dV / dQ and self-discharge current Isd of the battery to be tested by numerical solution using the least squares method based on the initial open circuit voltage V0, the initial cell temperature T0 and the at least three groups of charge and discharge data of the battery to be tested.

[0032] In a possible design, the charging and discharging module is specifically used to discharge the battery under test with a preset current for a preset time by connecting different resistors to the battery under test; and to charge the battery under test with a preset current for a preset time by connecting a charging device to the battery under test.

[0033] In a third aspect, the present application provides an electronic device, including a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus;

[0034] Memory, used to store computer programs;

[0035] The processor is used to implement the method steps described in the first aspect when executing the program stored in the memory.

[0036] In a fourth aspect, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method steps described in the first aspect are implemented.

[0037] Beneficial effects of the embodiments of the present application:

[0038] In an embodiment of the present application, by obtaining the initial open circuit voltage V0 and initial cell temperature T0 of the battery to be tested, and then charging or discharging the battery to be tested with a preset current for a preset time; after standing for a set period of time, the open circuit voltage and cell temperature of the battery to be tested are measured at least three times to obtain at least three groups of charge and discharge data of the battery to be tested. Based on the initial open circuit voltage V0, the initial cell temperature T0 and at least three groups of charge and discharge data of the battery to be tested, the cell temperature coefficient, voltage-to-capacity ratio and self-discharge current of the battery to be tested are obtained through numerical solution, so as to detect the self-discharge performance of the battery to be tested. The battery self-discharge detection method provided by the present application does not need to be placed for several days or weeks, and can shorten the time of battery self-discharge detection. In addition, the present application also takes into account the cell temperature coefficient and voltage-to-capacity ratio of the battery to be tested, and the self-discharge current obtained through numerical solution is more accurate.

[0039] The beneficial effects provided in the above-mentioned second aspect and various possible designs of the above-mentioned second aspect can refer to the beneficial effects brought about by the above-mentioned first aspect and various possible implementation methods of the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0041] Figure 1 A flow chart of a battery self-discharge detection method provided in an embodiment of the present application;

[0042] Figure 2 A logic diagram for calculating self-discharge current provided in an embodiment of the present application;

[0043] Figure 3 Another logic diagram for calculating the self-discharge current provided in an embodiment of the present application;

[0044] Figure 4 A logic diagram of calculating the self-discharge current when a preset current changes provided in an embodiment of the present application;

[0045] Figure 5 A schematic diagram of a discharge system provided in an embodiment of the present application;

[0046] Figure 6 A schematic diagram of a battery self-discharge detection device according to an embodiment of the present application;

[0047] Figure 7 A schematic diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0048] In this application, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c alone can represent: a, b, c, a and b, a and c, or a, b, and c, where a, b, and c can be single or multiple. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0049] The directions or positional relationships indicated by terms such as "center", "longitudinal", "lateral", "up", "down", "left", "right", "front", and "back" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0050] The terms "connected" and "connected" should be understood in a broad sense. For example, the "connected" or "connected" of a circuit structure can refer to not only physical connection, but also electrical connection or signal connection. For example, it can be directly connected, that is, physically connected, or indirectly connected through at least one intermediate element, as long as the circuit is connected, or it can be the internal connection of two elements; signal connection can refer to signal connection through a circuit or through a media medium, such as radio waves. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0051] In the related art, a constant current is supplied to an electric storage device, and the voltage of the electric storage device is measured. Based on the measured voltage of the electric storage device, the internal state of the electric storage device is calculated.

[0052] The present application provides a method for detecting the self-discharge performance of a battery which is different from the related art. Figure 1 , Figure 1 A battery self-discharge detection method provided in an embodiment of the present application includes:

[0053] S1, obtaining the initial open circuit voltage V0 and the initial cell temperature T0 of the battery to be tested.

[0054] For each battery, the battery cell temperature coefficient, voltage-to-capacity ratio, self-discharge current and other parameters are different. In the battery self-discharge detection process of the present application, in order to accurately obtain the self-discharge characteristics of the battery to be tested, it is necessary to measure the open circuit voltage and cell temperature of the battery to be tested.

[0055] During the test, it is necessary to first obtain the initial open circuit voltage V0 and initial cell temperature T0 of the battery to be tested. In one embodiment, a high-precision voltmeter can be used to measure the initial open circuit voltage V0 of the battery to be tested. The instrument for measuring the open circuit voltage of the battery to be tested is not specifically limited in this application. In one embodiment, the cell temperature of the battery to be tested can be measured by a temperature sensor, thermocouple or infrared measurement. The method for measuring the cell temperature of the battery to be tested is not specifically limited in this application.

[0056] S2, charging or discharging the battery to be tested with a preset current and for a preset time.

[0057] After the initial open circuit voltage V0 and the initial cell temperature T0 of the battery to be tested are measured, the battery to be tested is charged or discharged with a preset current for a preset time, wherein the preset current can be set according to the actual needs of the user, and generally the preset current is not higher than 100mA, and the preset time can also be set according to the actual needs of the user. In a possible embodiment, the battery to be tested is charged or discharged with a current of 1mA for 10 minutes.

[0058] S3, after standing for a set period of time, measuring the open circuit voltage and the cell temperature of the battery to be tested, and returning to the execution step: charging or discharging the battery to be tested with a preset current for a preset time, until the number of times of returning to the execution step is not less than twice, and at least three groups of charging and discharging data of the battery to be tested are obtained, wherein each time the step of charging or discharging the battery to be tested with a preset current for a preset time is returned, at least one of the preset current and the preset time is different, and the charging and discharging data includes: the preset current, the preset time, the open circuit voltage and the cell temperature.

[0059] After the battery to be tested is charged or discharged with a preset current for a preset time, it is necessary to stand for a set time period. After the standing for a set time period, the open circuit voltage and the cell temperature of the battery to be tested are measured again. After the measurement is completed, return to step S2, that is, the battery to be tested is charged or discharged with a preset current for a preset time. After the charging or discharging is completed, it is necessary to stand for a set time period again, and then measure the open circuit voltage and the cell temperature of the battery to be tested, until the number of times returning to step S2 is not less than two times, that is, it is necessary to perform the steps: charging or discharging the battery to be tested with a preset current for a preset time, standing for a set time period, and measuring the open circuit voltage and the cell temperature of the battery to be tested at least three times, and at least three groups of charging and discharging data of the battery to be tested can be obtained. Since the variables included in the process from charging or discharging the battery to be tested with a preset current for a preset time to measuring the open circuit voltage and the cell temperature of the battery to be tested are the preset current, the preset time, the open circuit voltage and the cell temperature, therefore, the charging and discharging data may include the preset current, the preset time, the open circuit voltage and the cell temperature.

[0060] The set time period can be set according to the needs of the user. In one example, the set time period can be 1 minute.

[0061] Since it is necessary to repeatedly perform the steps of charging or discharging the battery under test with a preset current for a preset time, and measuring the open circuit voltage and cell temperature of the battery under test after standing for a preset period of time. Each time this step is performed, at least one of the preset current and the preset time for charging or discharging the battery under test is different. In a possible embodiment, the preset current may be different and the preset time may be the same; the preset current may be the same and the preset time may be different; or both the preset current and the preset time may be different. Take the example of repeatedly executing the above steps three times, for example, the battery to be tested is charged or discharged at a current of 1mA for 10 minutes for the first time, the battery to be tested is charged or discharged at a current of 2mA for 10 minutes for the second time, and the battery to be tested is charged or discharged at a current of 3mA for 10 minutes for the third time; the battery to be tested is charged or discharged at a current of 5mA for 3 minutes for the first time, the battery to be tested is charged or discharged at a current of 5mA for 6 minutes for the second time, and the battery to be tested is charged or discharged at a current of 5mA for 10 minutes for the third time; the battery to be tested is charged or discharged at a current of 1mA for 3 minutes for the first time, the battery to be tested is charged or discharged at a current of 2mA for 6 minutes for the second time, and the battery to be tested is charged or discharged at a current of 3mA for 10 minutes for the third time.

[0062] S4, based on the initial open circuit voltage V0, the initial battery cell temperature T0 and the charge and discharge data of the at least three groups of the batteries to be tested, obtain the battery cell temperature coefficient, voltage-to-capacity ratio and self-discharge current of the battery to be tested through a numerical solution, wherein the self-discharge current is used to characterize the self-discharge characteristics of the battery to be tested.

[0063] The cell temperature coefficient is the coefficient of the open circuit voltage (OCV) of the battery changing with temperature, and its unit is V / ℃.

[0064] The state of charge (SOC) of a battery is a battery parameter, which is the remaining power of the battery.

[0065] The voltage-to-capacity ratio is also a characteristic parameter of the battery. When the SOC changes slightly, it is considered that the voltage-to-capacity ratio is constant, that is, during the measurement of the battery to be tested, the voltage-to-capacity ratio is constant.

[0066] In the present application, based on the initial open circuit voltage V0, the initial cell temperature T0, and the relationship between the charge and discharge data of at least three groups of the battery to be tested and the cell temperature coefficient, the voltage-to-capacity ratio, and the self-discharge current, the cell temperature coefficient, the voltage-to-capacity ratio, and the self-discharge current of the battery to be tested are obtained by numerical solution. In addition, since the self-discharge resistance is equal to the open circuit voltage divided by the self-discharge current, the self-discharge resistance can also be obtained after calculating the self-discharge current. The self-discharge resistance can also be used to characterize the self-discharge characteristics of the battery to be tested.

[0067] The battery self-discharge detection method in the present application is based on the fact that the battery cell temperature coefficient, voltage-to-capacity ratio and self-discharge current of each battery are different. In order to accurately obtain the self-discharge characteristics of the battery to be tested, three variables are set, namely the battery cell temperature coefficient, the voltage-to-capacity ratio and the self-discharge current. In order to calculate these three variables, at least three relationship equations need to be obtained to solve the battery cell temperature coefficient, the voltage-to-capacity ratio and the self-discharge current. Therefore, the battery self-discharge detection method provided by the present application needs to perform the following steps: the battery to be tested is charged or discharged with a preset current for a preset time; after standing for a set period of time, the open circuit voltage and the battery cell temperature of the battery to be tested are measured, and the steps are performed at least three times, and each time the step is performed, at least one of the preset current and the preset time for charging or discharging the battery to be tested is different (if the preset current and the preset time for charging or discharging the battery to be tested are the same each time the step is performed, at least three relationship equations cannot be obtained).

[0068] In an embodiment of the present application, by obtaining the initial open circuit voltage V0 and initial cell temperature T0 of the battery to be tested, and then charging or discharging the battery to be tested with a preset current for a preset time; after standing for a set period of time, the open circuit voltage and cell temperature of the battery to be tested are measured at least three times to obtain at least three groups of charge and discharge data of the battery to be tested. Based on the initial open circuit voltage V0, the initial cell temperature T0 and at least three groups of charge and discharge data of the battery to be tested, the cell temperature coefficient, voltage-to-capacity ratio and self-discharge current of the battery to be tested are obtained through numerical solution, so as to detect the self-discharge performance of the battery to be tested. The battery self-discharge detection method provided by the present application does not need to be placed for several days or weeks, and can shorten the time of battery self-discharge detection. In addition, the present application also takes into account the cell temperature coefficient and voltage-to-capacity ratio of the battery to be tested, and the self-discharge current obtained through numerical solution is more accurate.

[0069] In a possible embodiment, when the number of times the execution step is returned is twice, three sets of the charge and discharge data are obtained, and the charge and discharge data include: a first preset current I1, a first preset time t1, a first open circuit voltage V1, a first battery cell temperature T1, a second preset current I2, a second preset time t2, a second open circuit voltage V2, a second battery cell temperature T2, a third preset current I3, a third preset time t3, a third open circuit voltage V3, and a third battery cell temperature T3; the above step S4 includes:

[0070] Based on the initial open circuit voltage V0, the initial battery cell temperature T0, the first preset current I1, the first preset time t1, the first open circuit voltage V1, the first battery cell temperature T1, the second preset current I2, the second preset time t2, the second open circuit voltage V2, the second battery cell temperature T2, the third preset current I3, the third preset time t3, the third open circuit voltage V3, and the third battery cell temperature T3;

[0071] Use the formula: Q1=I1*t1+Isd*t1, Q2=I2*t2+Isd*t2, Q3=I3*t3+Isd*t3, V11=V1+C*(T1-T0), V22=V2+ C*(T2-T0), V33=V3+C*(T3-T0), ΔV1=V11-V0, ΔV2=V22-V11, ΔV3=V33-V22, dV / dQ=ΔV1 / Q1, dV / dQ=ΔV2 / Q2, dV / dQ=ΔV3 / Q3, wherein Q1 is the first charge, Q2 is the second charge, Q3 is the third charge, V11 is the first actual voltage, ΔV1 is the first voltage difference, V22 is the second actual voltage, ΔV2 is the second voltage difference, V33 is the third actual voltage, ΔV3 is the third voltage difference, Isd is the self-discharge current, dV / dQ is the voltage-to-capacity ratio, and C is the battery cell temperature coefficient of the battery;

[0072] The cell temperature coefficient C, voltage-to-capacity ratio dV / dQ and self-discharge current Isd of the battery to be tested are obtained by numerical solution.

[0073] In order to obtain three relationship equations about the three variables of battery cell temperature coefficient, voltage-to-capacity ratio and self-discharge current, the number of times the execution step is returned can be set to twice, and three sets of charge and discharge data can be obtained, namely, the first preset current I1, the first preset time t1, the first open circuit voltage V1, the first battery cell temperature T1, the second preset current I2, the second preset time t2, the second open circuit voltage V2, the second battery cell temperature T2, the third preset current I3, the third preset time t3, the third open circuit voltage V3, the third battery cell temperature T3, and also include: the initial open circuit voltage V0, the initial battery cell temperature T0.

[0074] According to the above data, three relationships (or equations) can be obtained, see Figure 2 , Figure 2 A logic for calculating the self-discharge current provided in this application is as follows: Figure 2 As shown, Q1 is the first electric quantity, which indicates the amount of electricity charged or discharged when the battery to be tested is charged or discharged for a first preset time at a first preset current; Q2 is the second electric quantity, which indicates the amount of electricity charged or discharged when the battery to be tested is charged or discharged for a second preset time at a second preset current; Q3 is the third electric quantity, which indicates the amount of electricity charged or discharged when the battery to be tested is charged or discharged for a third preset time at a third preset current. During the charging or discharging process, the amount of electricity charged or discharged includes two parts: one part is caused by the self-discharge current, and the other part is caused by the external charging current or the external discharging current. Therefore, the formula can be obtained: Q1 = I1*t1 + Isd*t1, Q2 = I2*t2 + Isd*t2, Q3 = I3*t3 + Isd*t3. It should be noted that, during discharge, the first preset current I1, the second preset current I2 and the third preset current I3 can be set to negative numbers, and the self-discharge current Isd is also negative; during charging, the first preset current I1, the second preset current I2 and the third preset current I3 can be set to positive numbers, and the self-discharge current Isd is negative.

[0075] See also Figure 2 , V11 is the first actual voltage, which is equal to the sum of the measured first open circuit voltage and the changing voltage caused by the change of the battery cell temperature, that is, V11=V1+C*(T1-T0); V22 is the second actual voltage, which is equal to the sum of the measured second open circuit voltage and the changing voltage caused by the change of the battery cell temperature, that is, V22=V2+C*(T2-T0); V33 is the third actual voltage, which is equal to the sum of the measured second open circuit voltage and the changing voltage caused by the change of the battery cell temperature, that is, V33=V3+C*(T3-T0).

[0076] See also Figure 2 , ΔV1 is the first voltage difference, representing the open circuit voltage difference measured for the first time; ΔV2 is the second voltage difference, representing the open circuit voltage difference measured for the second time; ΔV3 is the third voltage difference, representing the open circuit voltage difference measured for the third time. The formulas can be obtained: ΔV1 = V11-V0, ΔV2 = V22-V11, ΔV3 = V33-V22.

[0077] Based on dV / dQ=ΔV1 / Q1, dV / dQ=ΔV2 / Q2, dV / dQ=ΔV3 / Q3, three equations can be obtained. Since the equations include three unknowns: the cell temperature coefficient C, the voltage-to-capacity ratio dV / dQ and the self-discharge current Isd, based on the algorithm in matlab or python software, the cell temperature coefficient C, the voltage-to-capacity ratio dV / dQ, and the self-discharge current Isd of the battery to be tested can be obtained through numerical solution.

[0078] In a possible embodiment, when the number of times the execution step is returned is greater than twice, at least three sets of the charge and discharge data are obtained; the above-mentioned step S4 includes: based on the initial open circuit voltage V0, the initial battery cell temperature T0 and the at least three sets of charge and discharge data of the battery to be tested, using the least squares method, through a numerical solution, to obtain the battery cell temperature coefficient C, voltage-to-capacity ratio dV / dQ and self-discharge current Isd of the battery to be tested.

[0079] See also Figure 3 , Figure 3 Another logic for calculating the self-discharge current provided by this application is as follows: Figure 3 As shown, when the number of times the execution step is returned is greater than two times, at least three sets of charge and discharge data are obtained, that is, at least three measurements are performed, and multiple equations can be obtained. Since the equation includes three unknowns: the cell temperature coefficient C, the voltage-to-capacity ratio dV / dQ, and the self-discharge current Isd, based on the algorithm in matlab or python software, the least squares method is used, and the numerical solution is used for fitting optimization and solution, the cell temperature coefficient C, the voltage-to-capacity ratio dV / dQ, and the self-discharge current Isd of the battery to be tested can be obtained.

[0080] See also Figure 2 and Figure 3 For three measurements and more than three measurements, the present application provides two logics for calculating the self-discharge current, both of which can obtain the cell temperature coefficient C, voltage-to-capacity ratio dV / dQ, and self-discharge current Isd of the battery to be tested.

[0081] In a possible embodiment, when the preset current is a variable current, the product of the preset current and the preset time length is equal to the integral of the preset current and the preset time length.

[0082] The preset current in the present application can be a constant current value or a variable current value within the preset time period, for example, charging with a constant current of 1 mA for 10 minutes or charging with a variable current for 10 minutes. Figure 4 , FIG. 1 is a logic for calculating the self-discharge current when a preset current changes, provided in an embodiment of the present application, such as Figure 4As shown, when the preset current is a variable current, the product of the preset current and the preset time length is equal to the integral of the preset current and the preset time length.

[0083] Right now

[0084] In a possible embodiment, the above step S2 includes: discharging the battery under test with a preset current for a preset time by connecting different resistors to the battery under test; and charging the battery under test with a preset current for a preset time by connecting a charging device to the battery under test.

[0085] During the specific test process, the battery to be tested can be charged with a preset current and for a preset time by a charging device. Figure 5 , Figure 5 A schematic diagram of a discharge system provided in an embodiment of the present application is shown in FIG. Figure 5 As shown, different resistors may be connected to the battery to be tested, and the battery to be tested may be discharged with a preset current for a preset time. The specific method used in the test process is not specifically limited in the embodiment of the present application.

[0086] The present application also provides a battery self-discharge detection device, see Figure 6 , Figure 6 A schematic diagram of a self-discharge detection device provided in this application, such as Figure 6 As shown, the device comprises:

[0087] The acquisition module 601 is used to acquire the initial open circuit voltage V0 and the initial cell temperature T0 of the battery to be tested.

[0088] The charging and discharging module 602 is used to charge or discharge the battery to be tested with a preset current and for a preset time.

[0089] The measurement module 603 is used to measure the open circuit voltage and the cell temperature of the battery to be tested after standing for a set period of time, and return to the execution step: charging or discharging the battery to be tested with a preset current for a preset time, until the number of times the execution step is returned to is not less than twice, and at least three groups of charge and discharge data of the battery to be tested are obtained, wherein each time the execution step is returned to: charging or discharging the battery to be tested with a preset current for a preset time, at least one of the preset current and the preset time is different, and the charge and discharge data includes: the preset current, the preset time, the open circuit voltage and the cell temperature.

[0090] The calculation module 604 is used to obtain the cell temperature coefficient, voltage-to-capacity ratio and self-discharge current of the battery to be tested through a numerical solution based on the initial open circuit voltage V0, the initial cell temperature T0 and the at least three groups of charge and discharge data of the battery to be tested, wherein the self-discharge current is used to characterize the self-discharge characteristics of the battery to be tested.

[0091] In a possible embodiment, when the number of times the execution step is returned is twice, three sets of the charge and discharge data are obtained, and the charge and discharge data include: a first preset current I1, a first preset time t1, a first open circuit voltage V1, a first battery cell temperature T1, a second preset current I2, a second preset time t2, a second open circuit voltage V2, a second battery cell temperature T2, a third preset current I3, a third preset time t3, a third open circuit voltage V3, and a third battery cell temperature T3;

[0092] The calculation module 604 is specifically used to calculate the value of the first open circuit voltage V0, the first battery cell temperature T0, the first preset current I1, the first preset time t1, the first open circuit voltage V1, the first battery cell temperature T1, the second preset current I2, the second preset time t2, the second open circuit voltage V2, the second battery cell temperature T2, the third preset current I3, the third preset time t3, the third open circuit voltage V3, and the third battery cell temperature T3 based on the initial open circuit voltage V0, the initial battery cell temperature T0, the first preset current I1, the first preset time t1, the first open circuit voltage V1, the first battery cell temperature T1, the second preset current I2, the second preset time t2, the second open circuit voltage V2, the second battery cell temperature T2, the third preset current I3, the third preset time t3, the third open circuit voltage V3, and the third battery cell temperature T3; using the formula: Q1=I1*t1+Isd*t1, Q2=I2*t2+Isd*t2, Q3=I3*t3+Isd*t3, V11=V1+C*(T1-T0), V22=V2+C*(T2-T0), V33=V3+C*(T3-T0) , ΔV1=V11-V0, ΔV2=V22-V11, ΔV3=V33-V22, dV / dQ=ΔV1 / Q1, dV / dQ=ΔV2 / Q2, dV / dQ=ΔV3 / Q3, wherein, Q1 is the first charge, Q2 is the second charge, Q3 is the third charge, V11 is the first actual voltage, ΔV1 is the first voltage difference, V22 is the second actual voltage, ΔV2 is the second voltage difference, V33 is the third actual voltage, ΔV3 is the third voltage difference, Isd is the self-discharge current, dV / dQ is the voltage-to-capacity ratio, and C is the battery cell temperature coefficient of the battery; the battery cell temperature coefficient C, the voltage-to-capacity ratio dV / dQ and the self-discharge current Isd of the battery to be tested are obtained by numerical solution.

[0093] In a possible embodiment, when the number of times of returning to execute the step is greater than two times, at least three sets of the charging and discharging data are obtained;

[0094] The calculation module 604 is specifically used to obtain the cell temperature coefficient C, voltage-to-capacity ratio dV / dQ and self-discharge current Isd of the battery to be tested by numerical solution using the least squares method based on the initial open circuit voltage V0, the initial cell temperature T0 and the at least three groups of charge and discharge data of the battery to be tested.

[0095] In a possible embodiment, the charging and discharging module 602 is specifically used to discharge the battery under test with a preset current for a preset time by connecting different resistors to the battery under test; and to charge the battery under test with a preset current for a preset time by connecting a charging device to the battery under test.

[0096] The embodiment of the present application further provides an electronic device, including a processor 701, a communication interface 702, a memory 703 and a communication bus 704, wherein the processor 701, the communication interface 702, and the memory 703 communicate with each other through the communication bus 704;

[0097] Memory 703, used for storing computer programs;

[0098] The processor 701 is used to implement any of the steps of the battery self-discharge detection method described in the present application when executing the program stored in the memory 703.

[0099] The communication bus mentioned in the above electronic device can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The communication bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in the figure, but it does not mean that there is only one bus or one type of bus.

[0100] The communication interface is used for communication between the above electronic device and other devices.

[0101] The memory may include a random access memory (RAM) or a non-volatile memory (NVM), such as at least one disk memory. Optionally, the memory may also be at least one storage device located away from the aforementioned processor.

[0102] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0103] In another embodiment provided in the present application, a computer-readable storage medium is provided, in which a computer program is stored. When the computer program is executed by a processor, the steps of any of the above-mentioned battery self-discharge detection methods are implemented.

[0104] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media integrated. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk Solid State Disk (SSD)), etc.

[0105] Finally, it should be noted that the above embodiments are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto, and any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A battery self-discharge detection method, characterized in that: The method comprises: Obtain the initial open circuit voltage V0 and initial cell temperature T0 of the battery to be tested; Charging or discharging the battery to be tested with a preset current and for a preset time; After standing for a set period of time, measuring the open circuit voltage and the cell temperature of the battery to be tested, and returning to the execution step: charging or discharging the battery to be tested with a preset current for a preset time, until the number of times of returning to the execution step is not less than twice, and at least three sets of charge and discharge data of the battery to be tested are obtained, wherein each time the step of charging or discharging the battery to be tested with a preset current for a preset time is returned, at least one of the preset current and the preset time is different, and the charge and discharge data includes: the preset current, the preset time, the open circuit voltage and the cell temperature; Based on the initial open circuit voltage V0, the initial battery cell temperature T0 and the charge and discharge data of the at least three groups of the batteries to be tested, the battery cell temperature coefficient, voltage-to-capacity ratio and self-discharge current of the battery to be tested are obtained by numerical solution, wherein the self-discharge current is used to characterize the self-discharge characteristics of the battery to be tested.

2. The battery self-discharge detection method according to claim 1, characterized in that: When the number of times the execution step is returned is twice, three sets of the charge and discharge data are obtained, and the charge and discharge data include: a first preset current I1, a first preset time t1, a first open circuit voltage V1, a first battery cell temperature T1, a second preset current I2, a second preset time t2, a second open circuit voltage V2, a second battery cell temperature T2, a third preset current I3, a third preset time t3, a third open circuit voltage V3, and a third battery cell temperature T3; The method of obtaining the cell temperature coefficient, voltage-to-capacity ratio and self-discharge current of the battery to be tested by a numerical solution based on the initial open circuit voltage V0, the initial cell temperature T0 and the at least three groups of charge and discharge data of the battery to be tested comprises: Based on the initial open circuit voltage V0, the initial battery cell temperature T0, the first preset current I1, the first preset time t1, the first open circuit voltage V1, the first battery cell temperature T1, the second preset current I2, the second preset time t2, the second open circuit voltage V2, the second battery cell temperature T2, the third preset current I3, the third preset time t3, the third open circuit voltage V3, and the third battery cell temperature T3; Use the formula: Q1=I1*t1+Isd*t1, Q2=I2*t2+Isd*t2, Q3=I3*t3+Isd*t3, V11=V1+C*(T1-T0), V22=V2+ C*(T2-T0), V33=V3+C*(T3-T0), ΔV1=V11-V0, ΔV2=V22-V11, ΔV3=V33-V22, dV / dQ=ΔV1 / Q1, dV / dQ=ΔV2 / Q2, dV / dQ=ΔV3 / Q3, wherein Q1 is the first charge, Q2 is the second charge, Q3 is the third charge, V11 is the first actual voltage, ΔV1 is the first voltage difference, V22 is the second actual voltage, ΔV2 is the second voltage difference, V33 is the third actual voltage, ΔV3 is the third voltage difference, Isd is the self-discharge current, dV / dQ is the voltage-to-capacity ratio, and C is the battery cell temperature coefficient of the battery; The cell temperature coefficient C, voltage-to-capacity ratio dV / dQ and self-discharge current Isd of the battery to be tested are obtained by numerical solution.

3. The battery self-discharge detection method according to claim 1, characterized in that: When the number of times of returning to execute the step is greater than two times, at least three sets of the charging and discharging data are obtained; The method of obtaining the cell temperature coefficient, voltage-to-capacity ratio and self-discharge current of the battery to be tested by a numerical solution based on the initial open circuit voltage V0, the initial cell temperature T0 and the at least three groups of charge and discharge data of the battery to be tested comprises: Based on the initial open circuit voltage V0, the initial cell temperature T0 and the at least three groups of charge and discharge data of the battery to be tested, the cell temperature coefficient C, the voltage-to-capacity ratio dV / dQ and the self-discharge current Isd of the battery to be tested are obtained by numerical solution using the least squares method.

4. The battery self-discharge detection method according to claim 2, characterized in that: When the preset current is a variable current, the product of the preset current and the preset time length is equal to the integral of the preset current and the preset time length.

5. The battery self-discharge detection method according to claim 1, characterized in that: The charging or discharging of the battery to be tested with a preset current and for a preset time period includes: By connecting different resistors to the battery to be tested, the battery to be tested is discharged with a preset current for a preset time; The battery to be tested is charged with a preset current for a preset time by connecting an external charging device to the battery to be tested.

6. A battery self-discharge detection device, characterized in that: The device comprises: An acquisition module is used to obtain the initial open circuit voltage V0 and the initial cell temperature T0 of the battery to be tested; A charging and discharging module, used for charging or discharging the battery to be tested with a preset current and for a preset time; A measuring module, configured to measure the open circuit voltage and the cell temperature of the battery to be tested after standing for a set period of time, and return to the execution step: charging or discharging the battery to be tested with a preset current for a preset time, until the number of times of returning to the execution step is not less than twice, and at least three groups of charging and discharging data of the battery to be tested are obtained, wherein each time the execution step is returned: charging or discharging the battery to be tested with a preset current for a preset time, at least one of the preset current and the preset time is different, and the charging and discharging data includes: the preset current, the preset time, the open circuit voltage and the cell temperature; A calculation module is used to obtain the cell temperature coefficient, voltage-to-capacity ratio and self-discharge current of the battery to be tested through a numerical solution based on the initial open circuit voltage V0, the initial cell temperature T0 and the at least three groups of charge and discharge data of the battery to be tested, wherein the self-discharge current is used to characterize the self-discharge characteristics of the battery to be tested.

7. The battery self-discharge detection device according to claim 6, characterized in that: When the number of times the execution step is returned is twice, three sets of the charge and discharge data are obtained, and the charge and discharge data include: a first preset current I1, a first preset time t1, a first open circuit voltage V1, a first battery cell temperature T1, a second preset current I2, a second preset time t2, a second open circuit voltage V2, a second battery cell temperature T2, a third preset current I3, a third preset time t3, a third open circuit voltage V3, and a third battery cell temperature T3; The calculation module is specifically used based on the initial open circuit voltage V0, the initial battery cell temperature T0, the first preset current I1, the first preset time t1, the first open circuit voltage V1, the first battery cell temperature T1, the second preset current I2, the second preset time t2, the second open circuit voltage V2, the second battery cell temperature T2, the third preset current I3, the third preset time t3, the third open circuit voltage V3, and the third battery cell temperature T3; using the formula: Q1=I1*t1+Isd*t1, Q2=I2*t2+Isd*t2, Q3=I3*t3+Isd*t3, V11=V1+C*(T1-T0), V22=V2+C*(T2-T0), V33=V3+C*(T3-T0), Δ V1=V11-V0, ΔV2=V22-V11, ΔV3=V33-V22, dV / dQ=ΔV1 / Q1, dV / dQ=ΔV2 / Q2, dV / dQ=ΔV3 / Q3, wherein Q1 is the first charge, Q2 is the second charge, Q3 is the third charge, V11 is the first actual voltage, ΔV1 is the first voltage difference, V22 is the second actual voltage, ΔV2 is the second voltage difference, V33 is the third actual voltage, ΔV3 is the third voltage difference, Isd is the self-discharge current, dV / dQ is the voltage-to-capacity ratio, and C is the battery cell temperature coefficient of the battery; the battery cell temperature coefficient C, the voltage-to-capacity ratio dV / dQ and the self-discharge current Isd of the battery to be tested are obtained by numerical solution.

8. The battery self-discharge detection device according to claim 6, characterized in that: When the number of times of returning to execute the step is greater than two times, at least three sets of the charging and discharging data are obtained; The calculation module is specifically used to obtain the cell temperature coefficient C, voltage-to-capacity ratio dV / dQ and self-discharge current Isd of the battery to be tested by numerical solution using the least squares method based on the initial open circuit voltage V0, the initial cell temperature T0 and the at least three groups of charge and discharge data of the battery to be tested.

9. The battery self-discharge detection device according to claim 6, characterized in that: The charging and discharging module is specifically used to discharge the battery under test with a preset current for a preset time by connecting different resistors to the battery under test; and to charge the battery under test with a preset current for a preset time by connecting a charging device to the battery under test.

10. An electronic device, characterized in that: It includes a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus; Memory, used to store computer programs; A processor, for implementing the method steps described in any one of claims 1 to 5 when executing a program stored in a memory.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method steps described in any one of claims 1 to 5 are implemented.

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