A current measuring method, device, resistance measuring system, equipment and medium

Abstract

The present application discloses a current measurement method, device, resistance measurement system, equipment and medium. The current measurement method includes: obtaining the cell voltage and self-discharge current measured for the internal short-circuit cell at a first target temperature; the electrolyte is in a liquid state at the first target temperature; obtaining the cell resistance of the internal short-circuit cell at multiple different first preset temperatures as the first internal short-circuit resistance, and the electrolyte is in a solidified state at the first preset temperature; using each first internal short-circuit resistance, fitting the mapping relationship between the internal short-circuit resistance and the temperature; determining the second internal short-circuit resistance at the first target temperature based on the mapping relationship; using the cell voltage and the second internal short-circuit resistance, determining the physical self-discharge current at the first target temperature; using the difference between the self-discharge current and the physical self-discharge current as the chemical self-discharge current at the first target temperature. The above scheme separates physical self-discharge and chemical self-discharge, and realizes the accurate measurement of the chemical self-discharge current.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a current measurement method, device, resistance measurement system, equipment and medium. Background Art

[0002] The chemical reaction inside the battery cell will lead to chemical self-discharge. The analysis of the chemical self-discharge of the battery cell can reflect the performance of the battery cell. In the case of an internal short circuit in the battery cell, the self-discharge of the battery cell also includes the physical self-discharge caused by the internal short circuit. At this time, the self-discharge current of the battery cell includes the physical self-discharge current and the chemical self-discharge current.

[0003] In the prior art, it is usually impossible to separate the physical self-discharge current from the chemical self-discharge current in the self-discharge current, and it is difficult to accurately measure the chemical self-discharge current. Therefore, how to separate the physical self-discharge current from the chemical self-discharge current in the self-discharge current and accurately measure the chemical self-discharge current of the battery cell has become an urgent problem to be solved. Summary of the invention

[0004] The present application at least provides a current measurement method, device, resistance measurement system, equipment and medium.

[0005] The present application provides a current measurement method for an internal short circuit cell, comprising: obtaining a cell voltage and a self-discharge current measured for an internal short circuit cell at a first target temperature; wherein, at the first target temperature, the electrolyte in the internal short circuit cell is in a liquid state; obtaining the cell resistance of the internal short circuit cell at a plurality of different first preset temperatures as a first internal short circuit resistance of the internal short circuit cell corresponding to each first preset temperature, wherein, at the first preset temperature, the electrolyte in the internal short circuit cell is in a solidified state; using the first internal short circuit resistance at each first preset temperature, fitting a mapping relationship between the internal short circuit resistance and the temperature of the internal short circuit cell; determining a second internal short circuit resistance of the internal short circuit cell at the first target temperature based on the mapping relationship between the internal short circuit resistance and the temperature of the internal short circuit cell; determining a physical self-discharge current of the internal short circuit cell at the first target temperature using the cell voltage and the second internal short circuit resistance of the internal short circuit cell at the first target temperature; and using the difference between the self-discharge current and the physical self-discharge current of the internal short circuit cell at the first target temperature as the chemical self-discharge current of the internal short circuit cell at the first target temperature.

[0006] In the above scheme, when the electrolyte of the internal short circuit cell solidifies, the cell resistance is directly measured as the internal short circuit resistance, and the physical self-discharge of the cell is quantitatively analyzed based on the internal short circuit resistance and voltage, thereby separating the physical self-discharge from the chemical self-discharge and realizing the accurate measurement of the chemical self-discharge current.

[0007] In some embodiments, a plurality of different first preset temperatures are less than a preset temperature threshold, and / or the first target temperature is greater than a preset temperature threshold; wherein the preset temperature threshold is less than or equal to -40°C and greater than or equal to -80°C.

[0008] In the above solution, by setting a plurality of temperatures less than the preset temperature threshold as the first preset temperature, the condition of the battery cell at the first target temperature higher than the preset temperature threshold can be analyzed and obtained.

[0009] In some embodiments, there are multiple internal short circuit cells; the method also includes: determining a reference current based on the chemical self-discharge currents of the multiple internal short circuit cells; obtaining the self-discharge current of the cell to be tested at a first target temperature; and determining whether the cell to be tested has an internal short circuit based on the relationship between the self-discharge current of the cell to be tested and the reference current.

[0010] In the above scheme, the chemical self-discharge current of the internally shorted battery cell is quantified, so that the reference current corresponding to the battery cell to be tested can be accurately determined, which is used to determine whether the battery cell to be tested has an internal short, thereby improving the accuracy of the determination.

[0011] In some embodiments, determining a reference current based on the chemical self-discharge current of multiple short-circuited cells includes: performing central tendency statistics and discrete degree statistics on the chemical self-discharge current of multiple short-circuited cells to obtain central tendency statistical values ​​and discrete degree statistical values; determining a target deviation based on the discrete degree statistical value; and adjusting the central tendency statistical value using the target deviation to obtain a reference current.

[0012] In the above scheme, by statistically analyzing the chemical self-discharge currents of multiple short-circuited cells, the chemical self-discharge conditions of the short-circuited cells can be accurately characterized, so as to accurately determine the reference current corresponding to the cell to be tested.

[0013] In some embodiments, determining the target deviation based on the discrete degree statistic includes: using a preset multiple of the discrete degree statistic as the target deviation.

[0014] In the above solution, the preset multiple of the discrete degree statistical value is used as the target deviation to achieve the setting of the reference current corresponding to the battery cell to be tested.

[0015] In some embodiments, the short-circuited battery cell is disposed in a receiving device, and the short-circuited battery cell is placed at a plurality of different first preset temperatures by adding different amounts of refrigerant into the receiving device.

[0016] In the above scheme, the resistance of the battery cell at different temperatures can be measured by adjusting the amount of refrigerant.

[0017] In some embodiments, the cell resistance of the short-circuited cell at the first preset temperature is obtained by measuring the short-circuited cell using a resistance measuring device when the temperature of the short-circuited cell is measured to be the first preset temperature.

[0018] In the above scheme, the temperature of the battery cell is directly measured to accurately determine whether the battery cell is at a preset temperature.

[0019] In some embodiments, the temperature of the short-circuited battery cell is determined based on a first temperature and / or a second temperature; the first temperature is measured on the top of the short-circuited battery cell, and the second temperature is measured on the side of the short-circuited battery cell.

[0020] In the above solution, temperature measurement is performed at at least one position of the battery cell to achieve measurement of the battery cell temperature.

[0021] In some embodiments, the method further includes: after connecting the non-short-circuited battery cell in parallel with the resistor, obtaining the measured resistance of the non-short-circuited battery cell at multiple second preset temperatures, wherein at the second preset temperature, the electrolyte in the non-short-circuited battery cell is in a solidified state; based on the measured resistance at each second preset temperature, determining the estimated resistance of the non-short-circuited battery cell at a second target temperature, wherein at the second target temperature, the electrolyte in the non-short-circuited battery cell is in a liquid state; obtaining the resistance difference between the estimated resistance and the actual resistance of the resistor at the second target temperature, wherein the resistance difference is used to verify the validity of the physical self-discharge current and chemical self-discharge current of the internal short circuit battery cell obtained by this method at the first target temperature.

[0022] In the above scheme, a non-short-circuited cell is connected in parallel with a resistor to simulate an internal short-circuited cell, so as to verify the above method.

[0023] The present application provides a resistance measurement system, which is used to implement the current measurement method in any of the above items. The resistance measurement system includes a accommodating device, a temperature sensor and a resistance measuring device. The accommodating device is used to accommodate a battery cell, and the battery cell is an internally short-circuited battery cell or a non-short-circuited battery cell after being connected in parallel with a resistor. The accommodating device is provided with an inlet and outlet of a refrigerant, so that the refrigerant can be injected into or discharged from the accommodating device through the inlet and outlet; the temperature sensor is arranged in the accommodating device, and is used to measure the temperature of the battery cell; the resistance measuring device is used to measure the cell resistance of the battery cell, when the temperature sensor determines that the temperature of the battery cell is a preset temperature, as the internal short-circuit resistance of the battery cell at the preset temperature, wherein at the preset temperature, the electrolyte in the battery cell is in a solidified state.

[0024] In the above scheme, the resistance measurement system can realize temperature regulation of the battery cell, and measure the resistance of the battery cell when the temperature of the battery cell is determined to be a preset temperature, so as to be used as an internal short resistance, thereby being used to analyze the battery cell.

[0025] In some embodiments, a heat insulation layer is disposed inside the accommodation device.

[0026] In the above scheme, a heat insulating layer is provided to adjust the battery cell to a preset temperature.

[0027] In some embodiments, the temperature sensor includes at least one of a first sensor and a second sensor, the first sensor is configured to be disposed on the top of the battery cell, and the second sensor is configured to be disposed on the side of the battery cell.

[0028] In the above scheme, sensors are respectively arranged on the top and side of the battery cell to measure the temperature of the battery cell.

[0029] In some embodiments, the port of the resistance measuring device is used to connect to the electrode of the battery cell to measure the battery cell resistance.

[0030] In the above scheme, measurement is performed between the poles of the battery cell to obtain the resistance of the battery cell.

[0031] The present application provides a current measurement device for an internal short-circuit battery cell, comprising a first acquisition module, a second acquisition module, a resistance estimation module and a current determination module, wherein the first acquisition module is used to obtain a battery cell voltage and a self-discharge current measured for an internal short-circuit battery cell at a first target temperature; wherein, at the first target temperature, the electrolyte in the internal short-circuit battery cell is in a liquid state, and the second acquisition module is used to obtain the battery cell resistance of the internal short-circuit battery cell at a plurality of different first preset temperatures, as a first internal short-circuit resistance of the internal short-circuit battery cell corresponding to each first preset temperature, wherein, at the first preset temperature, the electrolyte in the internal short-circuit battery cell is in a solidified state; the resistance estimation module is used to obtain the battery cell resistance of the internal short-circuit battery cell at a plurality of different first preset temperatures, as a first internal short-circuit resistance of the internal short-circuit battery cell corresponding to each first preset temperature, and wherein, at the first preset temperature, the electrolyte in the internal short-circuit battery cell is in a solidified state; the resistance estimation module is used to obtain the battery cell voltage and the self-discharge current measured for an internal short-circuit battery cell at a first target temperature; and the self-discharge current of the internal short-circuit battery cell is measured at a first target temperature. The meter module is used to use the first internal short resistance of each first preset temperature to fit the mapping relationship between the internal short resistance of the internal short battery cell and the temperature; based on the mapping relationship between the internal short resistance of the internal short battery cell and the temperature, determine the second internal short resistance of the internal short battery cell at the first target temperature; the current determination module is used to use the cell voltage and the second internal short resistance of the internal short battery cell at the first target temperature to determine the physical self-discharge current of the internal short battery cell at the first target temperature; the difference between the self-discharge current of the internal short battery cell at the first target temperature and the physical self-discharge current is used as the chemical self-discharge current of the internal short battery cell at the first target temperature.

[0032] The present application provides an electronic device, including a memory and a processor, wherein the processor is used to execute program instructions stored in the memory, and when the program instructions are executed by the processor, the current measurement method of the above-mentioned internal short-circuited battery cell is implemented.

[0033] The present application provides a computer-readable storage medium having program instructions stored thereon, and when the program instructions are executed by a processor, the current measurement method of the above-mentioned internal short-circuited battery cell is implemented.

[0034] In the above scheme, when the electrolyte of the internal short circuit cell solidifies, the cell resistance is directly measured as the internal short circuit resistance, and the physical self-discharge of the cell is quantitatively analyzed based on the internal short circuit resistance and voltage, thereby separating the physical self-discharge from the chemical self-discharge and realizing the accurate measurement of the chemical self-discharge current.

[0035] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings herein are incorporated into the specification and constitute a part of the specification. These drawings illustrate embodiments consistent with the present application and are used together with the specification to illustrate the technical solution of the present application.

[0037] Figure 1 is a flow chart of a current measurement method for an internal short-circuited battery cell provided in some embodiments of the present application;

[0038] Figure 2 is a circuit diagram of an internal short-circuit battery cell provided in some embodiments of the present application;

[0039] Figure 3 is a flow chart of a current measurement method for an internal short-circuited battery cell provided in some embodiments of the present application;

[0040] Figure 4 is a schematic diagram of a resistance measurement system provided by some embodiments of the present application;

[0041] Figure 5 It is a schematic diagram of the framework of a current measuring device for an internally shorted battery cell provided in some embodiments of the present application;

[0042] Figure 6 is a schematic diagram of a framework of an electronic device provided in some embodiments of the present application;

[0043] Figure 7 It is a schematic diagram of the framework of the computer-readable storage medium provided in some embodiments of the present application. DETAILED DESCRIPTION

[0044] The scheme of the embodiment of the present application is described in detail below in conjunction with the drawings of the specification.

[0045] In the following description, for the purpose of explanation rather than limitation, specific details such as specific subsystem structures, interfaces, and technologies are provided to facilitate a thorough understanding of the present application.

[0046] The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the objects associated before and after are in an "or" relationship. In addition, "many" in this article means two or more than two. In addition, the term "at least one" in this article means any combination of at least two of any one or more of a plurality of, for example, including at least one of A, B, and C, can mean including any one or more elements selected from the set consisting of A, B, and C.

[0047] The internal short circuit of the battery cell will cause a physical self-discharge current, while the chemical reaction inside the battery cell will cause a chemical self-discharge current. The chemical self-discharge current and the physical self-discharge current together constitute the self-discharge current of the battery cell. However, generally speaking, it is impossible to distinguish the two parts of the self-discharge current of the battery cell. In the current measurement method of the internal short circuit battery cell disclosed in the embodiment of the present application, when the electrolyte of the internal short circuit battery cell is solidified, the battery cell resistance is directly measured as the internal short circuit resistance, and the physical self-discharge of the battery cell is quantitatively analyzed based on the internal short circuit resistance and the voltage, so that the physical self-discharge and chemical self-discharge can be separated, and the accurate measurement of the chemical self-discharge current can be achieved.

[0048] The current measurement method of the internal short-circuit battery cell disclosed in the embodiment of the present application can be applied to battery cells, and the type of battery cells is not limited.

[0049] See also Figure 1 , Figure 1 Flowchart of a current measurement method for a short-circuited cell provided in some embodiments of the present application. Specifically, the method may include:

[0050] Step S110: obtaining the cell voltage and self-discharge current measured for the internally shorted cell at the first target temperature.

[0051] Wherein, at the first target temperature, the electrolyte of the inner short cell is in a liquid state.

[0052] Step S120: Obtain the cell resistance of the internal short circuit cell at a plurality of different first preset temperatures as the first internal short circuit resistance of the internal short circuit cell corresponding to each first preset temperature.

[0053] Wherein, at the first preset temperature, the electrolyte in the short-circuited cell is in a solidified state. The cell resistance can be obtained by directly measuring the short-circuited cell.

[0054] See also Figure 2 , Figure 2 This is a circuit diagram of an internally shorted battery cell provided in some embodiments of the present application.

[0055] Figure 2 The equivalent circuit diagram of a battery cell with an internal short circuit is given, which includes branches a and b connected in parallel. It represents the short-circuit impedance caused by the internal short circuit. Branch b represents the equivalent circuit of the battery cell.

[0056] in, Represents the ohmic impedance of the battery cell, represents the electrochemical reaction impedance, represents the diffusion impedance, Represents double layer capacitance.

[0057] When the battery cell is at the first preset temperature, the electrolyte in the battery cell is in a solidified state, branch b can be considered to be in an open circuit state, and the impedance can be approximately infinite. At this time, the battery cell resistance directly measured on the battery cell can be considered as the internal short resistance.

[0058] In some embodiments, a preset temperature threshold may be set, and all first preset temperatures are lower than the preset temperature threshold.

[0059] Furthermore, the preset temperature threshold can be directly set as the critical temperature of electrolyte coagulation, and the electrolyte of the inner short cell is in a coagulated state when the temperature is lower than the preset temperature threshold. The specific value of the preset temperature threshold is related to the electrolyte and can be set according to actual application needs.

[0060] In some embodiments, the preset temperature threshold is less than or equal to -40°C and greater than or equal to -80°C.

[0061] In a specific application scenario, the preset temperature threshold is -45°C.

[0062] The number of the first preset temperatures can also be set according to actual application requirements, for example, 10 different first preset temperatures can be set. The specific value of each first preset temperature can also be set according to actual application requirements.

[0063] It should be noted that the cell resistance obtained by resistance measurement can indicate whether there is an internal short circuit in the cell being tested.

[0064] Step S130: using the first internal short-circuit resistance at each first preset temperature, a mapping relationship between the internal short-circuit resistance of the internal short-circuit battery cell and the temperature is obtained by fitting.

[0065] It should be noted that the internal short resistance of the internal short cell will change regularly with temperature. The first internal short resistance of multiple first preset temperatures can reflect the changing pattern between the internal short resistance and temperature, and can thus be used to determine the internal short resistance of the internal short cell at other temperatures.

[0066] It is understandable that the short circuit in the battery cell is usually caused by metal particles puncturing or burrs. The change of the short circuit resistance with temperature conforms to the following formula:

[0067]

[0068] Wherein, R represents the internal short-circuit resistance at temperature T, R0 represents the internal short-circuit resistance at temperature 0°C, and α represents the resistance temperature coefficient.

[0069] In a specific application scenario, by using the first internal short-circuit resistances corresponding to multiple different first preset temperatures and the above formula, R0 and α can be fitted to determine the mapping relationship between the internal short-circuit resistance of the internal short-circuit battery cell and the temperature.

[0070] Step S140: determining a second internal short resistance of the internal short resistance battery cell at the first target temperature based on a mapping relationship between the internal short resistance of the internal short resistance battery cell and the temperature.

[0071] It is understandable that after obtaining the mapping relationship between the internal short resistance of the internal short resistance battery cell and the temperature, the internal short resistance at any temperature can be determined, and the second internal short resistance at the first target temperature can be obtained.

[0072] In a specific application scenario, select T <T 临界 n temperature points (T1, T2, T3, T4...T n ) as multiple first preset temperatures. Where T 临界 It can indicate the critical temperature of electrolyte solidification. Test the cell resistance R at each temperature i (R i1 , R i2 , R i3 , R i4 ……R in ). Substituting multiple pairs of temperature-resistance data into the above formula and combining it with the least squares method, we can obtain the parameters and , and we get the mapping relationship between the internal short resistance and temperature.

[0073] Step S150: Determine the physical self-discharge current of the internal short circuit cell at the first target temperature by using the cell voltage of the internal short circuit cell at the first target temperature and the second internal short circuit resistance.

[0074] The cell voltage of the short-circuited cell at the first target temperature may be obtained by measuring the short-circuited cell.

[0075] It should be noted that the self-discharge current of the battery cell is composed of the physical self-discharge current and the chemical self-discharge current. If there is no internal short circuit in the battery cell, the self-discharge current is the chemical self-discharge current. If there is an internal short circuit in the battery cell, the self-discharge current is the sum of the physical self-discharge current and the chemical self-discharge current.

[0076] Among them, the physical self-discharge current is caused by the internal short circuit of the battery cell. The physical self-discharge current can be determined based on the battery cell voltage and the internal short circuit resistance.

[0077] In some embodiments, determining the physical self-discharge current of the internal short circuit cell at the first target temperature may include: taking the ratio of the cell voltage to the second internal short circuit resistance as the physical self-discharge current of the internal short circuit cell at the first target temperature.

[0078] Step S160: taking the difference between the self-discharge current of the short-circuited cell at the first target temperature and the physical self-discharge current as the chemical self-discharge current of the short-circuited cell at the first target temperature.

[0079] The self-discharge current may be obtained by testing the internal short-circuited battery cell at the first target temperature.

[0080] The first target temperature may be any temperature that does not cause irreversible damage to the battery cell. Specifically, if the electrolyte of the battery cell solidifies, it may cause irreversible damage to the battery cell. Therefore, the first target temperature may be any temperature greater than the critical temperature of electrolyte solidification.

[0081] In a specific application scenario, the critical temperature of electrolyte coagulation is used as the preset temperature threshold, a plurality of different first preset temperatures are lower than the preset temperature threshold, and the first target temperature is higher than the preset temperature threshold.

[0082] It is understandable that when setting the first target temperature, the convenience of the self-discharge current test may also be considered. A temperature threshold greater than or equal to the critical temperature may be set, and the first target temperature may be selected above the temperature threshold. Exemplarily, it may be in the range of 0°C-45°C, in the range of 15°C-25°C, and the room temperature of 25°C may be selected.

[0083] In a specific application scenario, a first threshold and a second threshold are set, a preset temperature is selected below the first threshold, and a target temperature is selected above the second threshold. The first threshold and the second threshold may be different.

[0084] The self-discharge current is composed of a physical self-discharge current and a chemical self-discharge current. Therefore, after obtaining the physical self-discharge current, the chemical self-discharge current of the battery cell can be obtained accordingly.

[0085] In a specific application scenario, after obtaining the internal short-circuit resistance R at the first target temperature i After that, the cell voltage of the short-circuited cell is expressed as U, then Can be used as the physical self-discharge current I of the internal short-circuit battery p The self-discharge current of the internal short-circuit cell is expressed as I test, the chemical self-discharge current is .

[0086] In some embodiments, ideally, the chemical self-discharge currents of different cells of the same category can be considered to be the same, where the cells of the same category have the same design. Therefore, the chemical self-discharge current of the internal short circuit cell can represent the self-discharge current of other cells of the same category without the internal short circuit.

[0087] When the chemical self-discharge current remains unchanged, there is a certain difference between the self-discharge current of the battery cell with an internal short and the self-discharge current of the battery cell without an internal short.

[0088] Since there is a certain difference between the self-discharge current of a battery cell with an internal short circuit and that of a battery cell without an internal short circuit, a reference current is set as the current critical value for distinguishing between batteries with internal short circuits and batteries without short circuits. Based on the relationship between the self-discharge current of the battery cell and the reference current, it can be determined whether the battery cell has an internal short circuit.

[0089] In some embodiments, a reference current is determined based on the chemical self-discharge current of the internally short-circuited cell, for comparison with the self-discharge current of the cell to be tested, to determine whether the cell to be tested has an internal short-circuit.

[0090] Furthermore, the reference current may be determined using the chemical self-discharge current of one or more internally shorted cells.

[0091] In the above scheme, quantitative analysis of the current of the internally short-circuited battery cell can accurately characterize the chemical self-discharge of the battery cell. The obtained chemical self-discharge current can be used to determine whether the battery cell has an internal short circuit, thereby improving the accuracy of the internal short circuit determination.

[0092] In a specific application scenario, for a large number of battery cells of the same type, a small number of internal short-circuited battery cells can be selected from them, and the internal short-circuited battery cells can be tested as above to determine the reference current corresponding to the large number of battery cells. In this way, the small batch of battery cells can be tested as above to accurately quantify the current of the battery cells. For large batches of battery cells, only the self-discharge current needs to be measured, and the short-circuit situation of large batches of battery cells can be determined non-destructively. For example, 50 internal short-circuited battery cells can be selected from 10,000 battery cells and tested as above.

[0093] See also Figure 3 , Figure 3 1 is a flow chart of a current measurement method for a short-circuited cell provided in some embodiments of the present application. Specifically, after obtaining the chemical self-discharge current of the short-circuited cell, the method may further include the following steps:

[0094] Step S310: determining a reference current based on the chemical self-discharge currents of a plurality of internal short-circuit cells.

[0095] It should be noted that if there is no internal short circuit in the battery cell, it can be said to be in a non-short circuit state. If the battery cell is completely short-circuited, it can be said to be in a complete internal short circuit state. When the state of the battery cell is between the complete internal short circuit state and the no short circuit state, it can be considered that the battery cell has different degrees of internal short circuit. Specifically, the degree of internal short circuit of the battery cell is different, the corresponding short circuit impedance has different resistance values, and the physical self-discharge current of the battery cell is also different. The battery cell with a smaller degree of internal short circuit has a smaller physical self-discharge current and a smaller self-discharge current.

[0096] By setting the reference current, the battery cells can be divided into two categories. The battery cells with a smaller self-discharge current can be considered to have no internal short circuit, while the battery cells with a larger self-discharge current can be considered to have an internal short circuit.

[0097] The reference current may be determined using the chemical self-discharge current of a plurality of internally shorted cells.

[0098] The cell to be tested and the cell with an internal short circuit belong to the same type of cell. Specifically, the cell design is the same. Ideally, the chemical self-discharge currents of different cells can be considered the same. Therefore, the chemical self-discharge current of the cell with an internal short circuit can represent the self-discharge current of the cell to be tested without a short circuit, and can be used to determine the reference current corresponding to the cell to be tested.

[0099] It is understandable that the chemical self-discharge currents of different short-circuited cells may not be exactly the same, and may fluctuate to a certain extent. The setting of the reference current may take into account the concentrated characteristics of the chemical self-discharge currents of all short-circuited cells, so as to set the reference current on the basis of accurately representing the chemical self-discharge conditions of this type of cell.

[0100] In one implementation scenario, the chemical self-discharge currents of multiple internal short-circuit cells can be statistically analyzed to obtain a statistical value of the chemical self-discharge current, which can be used to represent the chemical self-discharge of this type of cell. Therefore, the reference current is determined based on the statistical value of the statistical value.

[0101] In a specific application scenario, the central tendency statistical value may be an average value.

[0102] In some application scenarios, the central tendency statistical value can be directly used as the reference current.

[0103] In some application scenarios, adjustments may be made based on the central tendency statistical value, for example, the central tendency statistical value may be adjusted using the target deviation to obtain a reference current.

[0104] The target deviation may be set according to actual application requirements, for example, it may be a fixed preset value.

[0105] It is understandable that the chemical self-discharge currents of different short-circuited cells may not be exactly the same, and may fluctuate to a certain extent. Therefore, the setting of the reference current may also take into account the degree of current dispersion, so as to set a more reasonable reference current to distinguish between cells with short-circuited cells and cells without short-circuited cells.

[0106] In one implementation scenario, the chemical self-discharge currents of multiple internal short-circuit cells may be statistically analyzed to obtain a statistical value of the chemical self-discharge current. The statistical value of the statistical value of the discreteness may be used to determine the reference current.

[0107] In some application scenarios, a target deviation can be determined based on the discrete degree statistic, and the central tendency statistic can be adjusted using the target deviation to obtain a reference current. Specifically, a preset multiple of the discrete degree statistic can be used as the target deviation.

[0108] In a specific application scenario, the statistical value of the dispersion degree may be a standard deviation.

[0109] In a specific application scenario, for a battery cell with only chemical self-discharge, the self-discharge current I test That is the chemical self-discharge current I C , can be approximately considered to obey the distribution N( .in, represents the mean value of chemical self-discharge current, Represents the standard deviation of the chemical self-discharge current. The central tendency statistics and the dispersion statistics of the chemical self-discharge current of multiple short-circuited cells can be performed to obtain the mean value of all chemical self-discharge currents. and standard deviation The sum of the mean value and three times the standard deviation can be used as the reference current, expressed as .

[0110] The reference current may be set according to actual application requirements and may not be limited to the above methods.

[0111] Step S320: obtaining the self-discharge current of the battery cell to be tested at the first target temperature.

[0112] The chemical self-discharge current of the internal short circuit cell is at the first target temperature. Since temperature will affect the self-discharge of the cell, the self-discharge current of the cell to be tested obtained in step S320 is also at the first target temperature.

[0113] In a specific implementation scenario, the self-discharge current of the battery cell to be tested may be measured when the battery cell is at the first target temperature.

[0114] In some embodiments, at the first target temperature, the battery cell is charged at a constant voltage with the battery cell voltage of the short-circuited battery cell. During the constant voltage charging process, the current gradually becomes stable, and the steady-state current can be used as the self-discharge current of the short-circuited battery cell. The same is true for the self-discharge current of the battery cell to be tested.

[0115] It should be noted that the self-discharge current is affected by many factors, including but not limited to the cell temperature. The short-circuited cell and the cell to be tested are tested under the same conditions. Ideally, the chemical self-discharge current of the short-circuited cell and the cell to be tested is consistent, so that the chemical self-discharge current of the short-circuited cell can be used to represent the chemical self-discharge current of the cell to be tested.

[0116] Step S330: determining whether the battery cell to be tested has an internal short circuit based on the magnitude relationship between the self-discharge current and the reference current.

[0117] Specifically, the reference current is used as a critical value for distinguishing the self-discharge current of an internally short-circuited cell from that of a non-short-circuited cell. The self-discharge current of the cell to be tested is compared with the reference current to determine whether the cell to be tested is an internally short-circuited cell or a non-short-circuited cell.

[0118] In one implementation scenario, if the self-discharge current of the cell to be tested is greater than or equal to the reference current, it can be determined that the cell to be tested has an internal short circuit. If the self-discharge current of the cell to be tested is less than the reference current, it can be determined that the cell to be tested does not have an internal short circuit.

[0119] In one implementation scenario, if the self-discharge current of the tested cell is greater than the reference current, it can be determined that the tested cell has an internal short circuit. If the self-discharge current of the tested cell is less than or equal to the reference current, it can be determined that the tested cell has no internal short circuit.

[0120] See also Figure 4 , Figure 4 is a schematic diagram of a resistance measurement system provided in some embodiments of the present application.

[0121] Figure 4 Schematic diagram of a resistance measurement system 40 is shown, in which a battery cell 10 is placed.

[0122] The resistance measuring system 40 may include a housing device 41 , a temperature sensor 42 , and a resistance measuring device 43 .

[0123] The accommodating device 41 can accommodate the battery cell 10 (such as Figure 4 As shown). The accommodating device 41 may be provided with an inlet and outlet of the refrigerant, so that the refrigerant can be injected into or discharged from the accommodating device 41 through the inlet and outlet. For example, the refrigerant may be liquid nitrogen, such as Figure 4As shown, the refrigerant inlet and outlet include a liquid nitrogen inlet valve 411 and a liquid nitrogen outlet valve 412. Since the refrigerant may vaporize, the accommodating device 41 may also be provided with an exhaust valve 413 to discharge the vaporized refrigerant. In the figure, S represents the refrigerant liquid level.

[0124] The temperature sensor 42 may be disposed in the accommodating device 41 and may be used to measure the temperature of the battery cell 10 .

[0125] The resistance measuring device 43 can be used to measure the cell resistance of the cell 10 when the temperature of the cell 10 is determined to be a preset temperature based on the temperature sensor 42, so as to serve as the internal short-circuit resistance of the cell 10 at the preset temperature. Wherein, at the preset temperature, the electrolyte in the cell 10 is in a solidified state. The preset temperature can be any first preset temperature or second preset temperature.

[0126] In some embodiments, the accommodating device 41 may be provided with a heat insulating layer inside.

[0127] The number of the temperature sensor 42 may be one or more. The temperature sensor 42 may be used to directly measure the temperature of the battery cell 10 , and its position may be set according to actual application requirements. For example, it may be used to be set on the top or side of the battery cell 10 .

[0128] In some embodiments, the temperature sensor 42 includes a first sensor 421 and a second sensor 422. The first sensor 421 is used to be disposed on the top of the battery cell 10, and the second sensor 422 is used to be disposed on the side of the battery cell 10.

[0129] The two ports (the first port 431 and the second port 432 ) of the resistance measuring device 43 are used to be connected to the poles of the battery cell 10 to measure the battery cell resistance of the battery cell 10 .

[0130] In one implementation scenario, the accommodating device 41 may be an insulating barrel. The heat insulating layer may be an insulating material, for example, polystyrene foam, polyurethane foam, phenolic foam, asbestos or glass fiber. The refrigerant may be liquid nitrogen. The resistance measuring device 43 may be a resistance tester.

[0131] In some embodiments, the battery cell 10 can be disposed in a housing device 41, and a refrigerant can be added to the housing device 41. By controlling the amount of refrigerant added to the housing device 41, the temperature of the environment in which the battery cell 10 is located can be controlled to control the battery cell 10 to be at different first preset temperatures.

[0132] In some embodiments, the cell resistance may be obtained by measuring the cell 10 using a resistance measuring device 43 at a plurality of different first preset temperatures.

[0133] It should be noted that the cell resistance at the first preset temperature can be determined by directly measuring the temperature of the cell 10 , or can be determined indirectly by the ambient temperature of the cell 10 .

[0134] In some embodiments, the cell resistance of the battery cell 10 is obtained by measuring the battery cell 10 when the temperature of the battery cell 10 is measured to be a first preset temperature.

[0135] In some embodiments, the cell resistance of the battery cell 10 is determined by adjusting the temperature in the accommodation device 41 to a first preset temperature and placing the battery cell 10 in an environment of the first preset temperature for a period of time, so that the temperature of the battery cell 10 can be considered to have reached the first preset temperature.

[0136] In one implementation scenario, whether the battery cell 10 is at the first preset temperature can be determined by measuring with a temperature sensor. One or more temperature sensors can be provided to determine whether the battery cell 10 is at the first preset temperature according to the temperature measured by each temperature sensor.

[0137] In some embodiments, the temperature of the battery cell 10 is determined based on a first temperature and / or a second temperature, where the first temperature is measured at a top of the battery cell 10 and the second temperature is measured at a side of the battery cell 10 .

[0138] In one implementation scenario, the average of the first temperature and the second temperature can be used as the target cell temperature to determine whether the temperature is the first preset temperature. Of course, other methods can also be used to determine the temperature of the cell 10 based on the first temperature and the second temperature.

[0139] The battery cell 10 may be an internally short-circuited battery cell or a non-short-circuited battery cell with a resistor connected in parallel.

[0140] In a specific application scenario, the battery cell 10 is placed in an insulated barrel and cooled by injecting liquid nitrogen. Two external temperature sensors 42 detect the battery cell temperature (top and side) in real time. The port of the resistance tester is connected to the pole of the battery cell 10 for real-time resistance testing. Initially, the temperature of the battery cell 10 is relatively high, and the liquid nitrogen contacts the battery cell 10 and vaporizes rapidly. The liquid nitrogen exhaust valve is always open to promptly remove the gas generated by vaporization. As the battery cell temperature continues to decrease, the vaporization rate gradually decreases, and liquid nitrogen is continuously injected, and the liquid nitrogen level gradually rises (the liquid nitrogen level does not exceed the temperature sensor 42). The temperature sensor 42 detects the battery cell temperature T <T 临界 , close the liquid nitrogen exhaust valve. Adjust the temperature of the battery cell by adjusting the liquid nitrogen level (liquid nitrogen can be injected through the liquid nitrogen inlet valve, or liquid nitrogen can be discharged through the liquid nitrogen outlet valve), so that the battery cell 10 is at different first preset temperatures at different times. After the experiment, discharge the remaining liquid nitrogen through the liquid nitrogen outlet valve and take out the battery cell 10.

[0141] In some embodiments, a non-short-circuited cell may be connected in parallel with a resistor to simulate an internal short-circuited cell. After connecting the non-short-circuited cell and the resistor in parallel, the measured resistance of the non-short-circuited cell at multiple second preset temperatures is obtained. Based on the measured resistance at each second preset temperature, the estimated resistance of the non-short-circuited cell at the second target temperature is determined. The resistance difference between the estimated resistance and the actual resistance of the resistor at the second target temperature is obtained.

[0142] Wherein, at the second preset temperature, the electrolyte in the battery cell 10 is in a solidified state. At the second target temperature, the electrolyte in the battery cell 10 is in a liquid state.

[0143] The above resistance difference can be used to verify the validity of the physical self-discharge current and chemical self-discharge current of the internal short-circuited battery cell at the first target temperature obtained by the present method. Exemplarily, if the resistance difference is less than a certain difference threshold, the above current measurement method can be considered to be relatively accurate.

[0144] In a specific application scenario, a resistor with known actual resistance can be selected and connected in parallel with a non-short-circuited cell. Multiple resistors with different actual resistances can be selected for multiple verifications. The actual resistance and estimated resistance used in multiple verifications are shown in the following table:

[0145]

[0146] The resistance difference between the actual resistance and the estimated resistance is <1%.

[0147] The non-short-circuited battery cell may be of the same type or different types as the internal short-circuited battery cell. If they are different types of battery cells, the solidification temperatures of the electrolytes of the two may be different, and the preset temperature and the target temperature may be set respectively corresponding to their respective solidification temperatures.

[0148] It is understood that the number of the second preset temperatures may be the same as or different from the number of the first preset temperatures. The value of the second preset temperature may be the same as or different from the value of the first preset temperature. The first target temperature may be the same as or different from the second target temperature.

[0149] In a specific application scenario, multiple temperatures less than a preset temperature threshold are selected as multiple first preset temperatures and multiple second preset temperatures, and a temperature greater than the preset temperature threshold is selected as the first target temperature and the second target temperature.

[0150] It should be noted that the short-circuited battery cells selected in the above experiments may not be completely short-circuited battery cells.

[0151] It is understandable that the experiment of measuring the resistance of the short-circuited cell will cause the electrolyte to solidify, which may cause irreversible damage to the short-circuited cell. The self-discharge current test can be a non-destructive test, so the self-discharge current test of the short-circuited cell can be performed first, and then the resistance measurement can be performed.

[0152] See also Figure 5 , Figure 5 It is a schematic diagram of the framework of a current measuring device for an internally shorted battery cell provided in some embodiments of the present application.

[0153] The current measuring device 50 for the short-circuited cell includes a first acquisition module 51 and a second acquisition module 52, a resistance estimation module 53 and a current determination module 54, wherein the first acquisition module 51 is used to obtain the cell voltage and self-discharge current measured for the short-circuited cell at a first target temperature; wherein, at the first target temperature, the electrolyte in the short-circuited cell is in a liquid state, and the second acquisition module 52 is used to obtain the cell resistance of the short-circuited cell at a plurality of different first preset temperatures, as the first short-circuited cell resistance corresponding to each first preset temperature, wherein, at the first preset temperature, the electrolyte in the short-circuited cell is in a solidified state; the resistance estimation module 53 is used to obtain the cell resistance of the short-circuited cell at a plurality of different first preset temperatures, as the first short-circuited cell resistance corresponding to each first preset temperature. The measuring module 53 is used to use the first short-circuit resistance of each first preset temperature to fit the mapping relationship between the short-circuit resistance of the short-circuit battery cell and the temperature; based on the mapping relationship between the short-circuit resistance of the short-circuit battery cell and the temperature, determine the second short-circuit resistance of the short-circuit battery cell at the first target temperature; the current determination module 54 is used to use the cell voltage and the second short-circuit resistance of the short-circuit battery cell at the first target temperature to determine the physical self-discharge current of the short-circuit battery cell at the first target temperature; the difference between the self-discharge current of the short-circuit battery cell at the first target temperature and the physical self-discharge current is used as the chemical self-discharge current of the short-circuit battery cell at the first target temperature.

[0154] In the above scheme, when the electrolyte of the internal short circuit cell solidifies, the cell resistance is directly measured as the internal short circuit resistance, and the physical self-discharge of the cell is quantitatively analyzed based on the internal short circuit resistance and voltage, so as to accurately understand the cell state and separate the physical self-discharge and chemical self-discharge, and realize the accurate measurement of the chemical self-discharge current.

[0155] In some embodiments, a plurality of different first preset temperatures are less than a preset temperature threshold, and / or the first target temperature is greater than a preset temperature threshold; wherein the preset temperature threshold is less than or equal to -40°C and greater than or equal to -80°C.

[0156] In the above solution, by setting a plurality of temperatures less than the preset temperature threshold as the first preset temperature, the condition of the battery cell at the first target temperature higher than the preset temperature threshold can be analyzed and obtained.

[0157] In some embodiments, there are multiple internal short circuit cells; the current measuring device 50 for the internal short circuit cell also includes a judgment module, which is used to determine a reference current based on the chemical self-discharge currents of the multiple internal short circuit cells; obtain the self-discharge current of the cell to be tested at the first target temperature; and determine whether the cell to be tested has an internal short circuit based on the relationship between the self-discharge current of the cell to be tested and the reference current.

[0158] In the above scheme, the chemical self-discharge current of the internally shorted battery cell is quantified, so that the reference current corresponding to the battery cell to be tested can be accurately determined, which is used to determine whether the battery cell to be tested has an internal short, thereby improving the accuracy of the determination.

[0159] In some embodiments, the judgment module is used to determine a reference current based on the chemical self-discharge current of multiple short-circuited batteries, specifically including: performing central tendency statistics and discrete degree statistics on the chemical self-discharge current of multiple short-circuited batteries, respectively, to obtain central tendency statistical values ​​and discrete degree statistical values; determining a target deviation based on the discrete degree statistical value; and using the target deviation to adjust the central tendency statistical value to obtain a reference current.

[0160] In the above scheme, by statistically analyzing the chemical self-discharge currents of multiple short-circuited cells, the chemical self-discharge conditions of the short-circuited cells can be accurately characterized, so as to accurately determine the reference current corresponding to the cell to be tested.

[0161] In some embodiments, the judgment module is used to determine the target deviation based on the discrete degree statistic value, specifically including: taking a preset multiple of the discrete degree statistic value as the target deviation.

[0162] In the above solution, the preset multiple of the discrete degree statistical value is used as the target deviation to achieve the setting of the reference current corresponding to the battery cell to be tested.

[0163] In some embodiments, the short-circuited battery cell is disposed in a receiving device, and the short-circuited battery cell is placed at a plurality of different first preset temperatures by adding different amounts of refrigerant into the receiving device.

[0164] In the above scheme, the resistance of the battery cell at different temperatures can be measured by adjusting the amount of refrigerant.

[0165] In some embodiments, the cell resistance of the short-circuited cell at the first preset temperature is obtained by measuring the short-circuited cell using a resistance measuring device when the temperature of the short-circuited cell is measured to be the first preset temperature.

[0166] In the above scheme, the temperature of the battery cell is directly measured to accurately determine whether the battery cell is at a preset temperature.

[0167] In some embodiments, the temperature of the short-circuited battery cell is determined based on a first temperature and / or a second temperature; the first temperature is measured on the top of the short-circuited battery cell, and the second temperature is measured on the side of the short-circuited battery cell.

[0168] In the above solution, temperature measurement is performed at at least one position of the battery cell to achieve measurement of the battery cell temperature.

[0169] In some embodiments, the current measuring device 50 for the internal short circuit cell also includes a verification module, which is used to obtain the measured resistance of the non-short circuit cell at multiple second preset temperatures after the non-short circuit cell is connected in parallel with the resistor, determine the estimated resistance of the non-short circuit cell at the second target temperature based on the measured resistance at each second preset temperature, and obtain the resistance difference between the estimated resistance and the actual resistance of the resistor at the second target temperature, wherein at the second preset temperature, the electrolyte in the non-short circuit cell is in a solidified state; at the second target temperature, the electrolyte in the non-short circuit cell is in a liquid state; the resistance difference is used to verify the validity of the physical self-discharge current and chemical self-discharge current of the internal short circuit cell at the first target temperature obtained using this method.

[0170] In the above scheme, a non-short-circuited cell is connected in parallel with a resistor to simulate an internal short-circuited cell, so as to verify the above method.

[0171] See also Figure 6 , Figure 6 It is a schematic diagram of the framework of an electronic device provided in some embodiments of the present application.

[0172] The electronic device 60 includes a memory 61 and a processor 62. The processor 62 is used to execute program instructions stored in the memory 61. When the program instructions are executed by the processor 62, the above-mentioned current measurement method of any internal short-circuited battery cell is implemented. In a specific implementation scenario, the electronic device 60 may include, but is not limited to: computer equipment, power-consuming equipment, microcomputers, desktop computers, servers, and in addition, the electronic device 60 may also include mobile devices such as laptops and tablet computers, which are not limited here.

[0173] Specifically, the processor 62 is used to control itself and the memory 61 to implement the above-mentioned current measurement method of any internal short-circuited battery cell. The processor 62 can also be called a CPU (Central Processing Unit). The processor 62 may be an integrated circuit chip with signal processing capabilities. The processor 62 can also be a general-purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application-specific integrated circuit (Application Specific Integrated Circuit, ASIC), a field-programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. In addition, the processor 62 can be implemented by an integrated circuit chip.

[0174] See also Figure 7 , Figure 7 It is a schematic diagram of the framework of the computer-readable storage medium provided in some embodiments of the present application.

[0175] The computer-readable storage medium 70 stores program instructions 71 that can be executed by a processor. When the program instructions 71 are executed by the processor, they are used to implement the above-mentioned current measurement method for any internal short-circuited battery cell.

[0176] The above description of various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced to each other, and for the sake of brevity, they will not be repeated herein.

[0177] In the several embodiments provided in the present application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device implementation described above is only schematic. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation, such as units or components can be combined or integrated into another subsystem, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0178] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit. If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or part of the contribution to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (processor) to perform all or part of the steps of each implementation method of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program code.

Claims

1. A method for measuring the current of an internal short-circuit battery cell, characterized in that: The method comprises: Obtaining a cell voltage and a self-discharge current measured for the short-circuited cell at a first target temperature; wherein, at the first target temperature, the electrolyte in the short-circuited cell is in a liquid state; Obtaining the cell resistance of the short-circuit battery cell at a plurality of different first preset temperatures as the first short-circuit resistance of the short-circuit battery cell corresponding to each of the first preset temperatures, wherein at the first preset temperature, the electrolyte in the short-circuit battery cell is in a solidified state; Using the first internal short-circuit resistance of each first preset temperature, a mapping relationship between the internal short-circuit resistance of the internal short-circuit battery cell and the temperature is obtained by fitting; Based on a mapping relationship between the internal short-circuit resistance of the internal short-circuit battery cell and the temperature, determining a second internal short-circuit resistance of the internal short-circuit battery cell at the first target temperature; Determine a physical self-discharge current of the internal short-circuit battery cell at the first target temperature by using the battery cell voltage of the internal short-circuit battery cell at the first target temperature and the second internal short-circuit resistance; The difference between the self-discharge current of the short-circuit battery cell at the first target temperature and the physical self-discharge current is used as the chemical self-discharge current of the short-circuit battery cell at the first target temperature.

2. The current measuring method according to claim 1, characterized in that: The multiple different first preset temperatures are lower than a preset temperature threshold, and / or the first target temperature is higher than a preset temperature threshold; The preset temperature threshold is less than or equal to -40°C and greater than or equal to -80°C.

3. The current measuring method according to claim 1, characterized in that: There are multiple internal short-circuit cells; and the method further includes: Determining a reference current based on the chemical self-discharge current of the plurality of internal short-circuit cells; Obtaining the self-discharge current of the battery cell to be tested at the first target temperature; Based on the magnitude relationship between the self-discharge current of the battery cell to be tested and the reference current, it is determined whether the battery cell to be tested has an internal short circuit.

4. The current measuring method according to claim 3, characterized in that: The determining of the reference current based on the chemical self-discharge current of the plurality of internal short-circuit cells comprises: Performing central tendency statistics and discrete degree statistics on the chemical self-discharge currents of the plurality of internal short-circuit cells to obtain central tendency statistical values ​​and discrete degree statistical values; Determining a target deviation based on the dispersion statistics; The central tendency statistical value is adjusted using the target deviation to obtain the reference current.

5. The current measuring method according to claim 4, characterized in that: Determining the target deviation based on the discrete degree statistics includes: A preset multiple of the discrete degree statistical value is used as the target deviation.

6. The current measuring method according to claim 1, characterized in that: The internal short-circuit battery cell is arranged in a receiving device, and the internal short-circuit battery cell is at a plurality of different first preset temperatures by adding different amounts of refrigerant into the receiving device; The cell resistance of the short-circuited cell at the first preset temperature is obtained by measuring the short-circuited cell using a resistance measuring device when the temperature of the short-circuited cell is measured to be the first preset temperature.

7. The current measuring method according to claim 6, characterized in that: The temperature of the short inner cell is determined based on a first temperature and / or a second temperature; the first temperature is measured at the top of the short inner cell, and the second temperature is measured at the side of the short inner cell.

8. The current measuring method according to claim 1, characterized in that: The method further comprises: After connecting the non-short-circuit battery cell and the resistor in parallel, obtaining the measured resistance of the non-short-circuit battery cell at a plurality of second preset temperatures, wherein at the second preset temperature, the electrolyte in the non-short-circuit battery cell is in a solidified state; Determining an estimated resistance of the non-short-circuited battery cell at a second target temperature based on the measured resistance at each of the second preset temperatures, wherein at the second target temperature, the electrolyte in the non-short-circuited battery cell is in a liquid state; Obtain a resistance difference between the estimated resistance and the actual resistance of the resistor at the second target temperature, wherein the resistance difference is used to verify the validity of the physical self-discharge current and the chemical self-discharge current of the internal short-circuited battery cell at the first target temperature obtained using this method.

9. A resistance measurement system, characterized in that: The resistance measurement system is used to implement the current measurement method according to any one of claims 1 to 8, and the resistance measurement system comprises: A containing device, the containing device is used to contain a battery cell, the battery cell is an internal short circuit battery cell or a non-short circuit battery cell after being connected in parallel with a resistor, and the containing device is provided with an inlet and outlet of a refrigerant, so that the refrigerant can be injected into or discharged from the containing device through the inlet and outlet; A temperature sensor, which is disposed in the accommodating device and is used to measure the temperature of the battery cell; A resistance measuring device is used to measure the cell resistance of the battery cell when the temperature of the battery cell is determined to be a preset temperature based on the temperature sensor, so as to serve as the internal short-circuit resistance of the battery cell at the preset temperature, wherein at the preset temperature, the electrolyte in the battery cell is in a solidified state.

10. The resistance measurement system according to claim 9, characterized in that: A heat insulation layer is provided inside the accommodating device; And / or, the temperature sensor includes at least one of a first sensor and a second sensor, the first sensor is used to be arranged on the top of the battery cell, and the second sensor is used to be arranged on the side of the battery cell; And / or, the port of the resistance measuring device is used to be connected to the pole of the battery cell to measure the battery cell resistance of the battery cell.

11. A current measuring device for an internal short-circuited battery cell, characterized in that: include: A first acquisition module is used to obtain a cell voltage and a self-discharge current measured for an internal short-circuited cell at a first target temperature; wherein, at the first target temperature, the electrolyte in the internal short-circuited cell is in a liquid state; A second acquisition module is used to acquire the cell resistance of the internal short circuit cell at a plurality of different first preset temperatures as the first internal short circuit resistance of the internal short circuit cell corresponding to each first preset temperature, wherein at the first preset temperature, the electrolyte in the internal short circuit cell is in a solidified state; A resistance estimation module, used to fit the mapping relationship between the internal short resistance and the temperature of the internal short resistance battery cell by using the first internal short resistance of each first preset temperature; based on the mapping relationship between the internal short resistance and the temperature of the internal short resistance battery cell, determine the second internal short resistance of the internal short resistance battery cell at the first target temperature; A current determination module is used to determine the physical self-discharge current of the internal short circuit cell at the first target temperature by using the cell voltage of the internal short circuit cell at the first target temperature and the second internal short circuit resistance; and use the difference between the self-discharge current of the internal short circuit cell at the first target temperature and the physical self-discharge current as the chemical self-discharge current of the internal short circuit cell at the first target temperature.

12. An electronic device, characterized in that: The invention comprises a memory and a processor, wherein the memory stores program instructions, and the program instructions are used to execute the current measuring method according to any one of claims 1 to 8 when executed by the processor.

13. A computer-readable storage medium having program instructions stored thereon, characterized in that: When the program instructions are executed by a processor, the current measuring method according to any one of claims 1 to 8 is implemented.

Images