Method, device, equipment, system and medium for detecting internal short circuit of battery cell

Abstract

The present application discloses a method, device, equipment, system and medium for detecting internal short circuit of a battery cell. The method for detecting internal short circuit of a battery cell includes: obtaining measured electrical parameters of a target battery cell at different temperatures, wherein the measured electrical parameters include at least one of voltage and resistance, and the reference parameter characteristics include at least one of reference distribution characteristics and reference change trends; and obtaining reference parameter characteristics corresponding to a plurality of preset battery cell states, wherein the plurality of preset battery cell states include a short circuit state and a micro short circuit state; from the plurality of preset battery cell states, selecting a preset battery cell state whose reference parameter characteristics match the measured electrical parameters as the battery cell state of the target battery cell. The above scheme can improve the accuracy of internal short circuit detection.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a method, device, equipment, system and medium for detecting internal short circuits in battery cells. Background Art

[0002] The internal short circuit of the battery cell will affect the storage and use of the battery cell. For example, the self-discharge caused by the internal short circuit will cause the battery cell to fail during storage due to low voltage, zero voltage, etc. The internal short circuit may cause poor self-discharge consistency among a batch of battery cells in the battery pack, leading to safety problems such as overcharging and over-discharging, ultimately reducing the life of the battery module or causing safety problems.

[0003] The current detection method for internal short circuit of battery cells cannot accurately detect whether there is an internal short circuit in the battery cell. For example, a battery cell with an internal short circuit may be mistakenly judged as a battery cell without a short circuit. Summary of the invention

[0004] The present application at least provides a method, device, equipment, system and medium for detecting internal short circuit of a battery cell.

[0005] The present application provides a method for detecting internal short circuit of a battery cell, comprising: obtaining measured electrical parameters of a target battery cell at different temperatures, wherein the measured electrical parameters include at least one of voltage and resistance; and obtaining reference parameter characteristics corresponding to multiple preset battery cell states, wherein the multiple preset battery cell states include a short circuit state and a micro-short circuit state, and the reference parameter characteristics include at least one of a reference distribution characteristic and a reference change trend; from the multiple preset battery cell states, selecting a preset battery cell state whose reference parameter characteristics match the measured electrical parameters as the battery cell state of the target battery cell.

[0006] In the above scheme, the measured electrical parameters of the target battery cell at different temperatures are obtained. Compared with the judgment based on the electrical parameters at a single temperature, the measured electrical parameters at different temperatures can more comprehensively reflect the characteristics of the target battery cell, and are compared with the reference parameter characteristics of multiple preset battery cell states. The preset battery cell states include short circuit and micro short circuit, which can determine whether the target battery cell has a short circuit or micro short circuit, thereby improving the accuracy of internal short circuit detection.

[0007] In some embodiments, the reference distribution characteristic characterizes that the electrical parameter in a preset battery cell state satisfies a preset size relationship with the electrical parameter threshold, and the reference change trend characterizes the change trend of the electrical parameter in a preset battery cell state with temperature change, and the temperature change is temperature drop or temperature rise.

[0008] In the above scheme, two types of reference parameter characteristics are set for selection, which reflect the characteristics of the battery cell under the preset battery cell state from different angles, and can more flexibly realize the detection of internal short circuit of the battery cell.

[0009] In some embodiments, the reference distribution characteristics corresponding to the short circuit state include that the electrical parameters corresponding to different temperatures are all less than the first electrical parameter threshold; the reference distribution characteristics corresponding to the micro short circuit state include that the electrical parameters corresponding to the first temperature interval are less than the second electrical parameter threshold, and the electrical parameters corresponding to the second temperature interval are greater than the second electrical parameter threshold; the reference change trend corresponding to the short circuit state includes that the electrical parameters are in a stable state during the temperature change process, and the stable state is that the electrical parameters remain unchanged or the change amplitude remains within a preset range; when the electrical parameters include resistance, the reference change trend corresponding to the micro short circuit state includes the existence of a forward resistance change trend during the temperature change process, and the forward resistance change trend indicates that the resistance is positively correlated with the temperature; when the electrical parameters include voltage, the reference change trend corresponding to the micro short circuit state includes the existence of a forward voltage change trend and a voltage stabilization trend in sequence during the temperature change process, the forward voltage change trend indicates that the voltage is positively correlated with the temperature, and the voltage stabilization trend indicates that the voltage is in a stable state as the temperature changes.

[0010] In the above scheme, reference distribution characteristics corresponding to the short circuit state and the micro short circuit state are set respectively, and reference change trends of the short circuit state and the micro short circuit state are provided, and two types of reference parameter characteristics are provided to determine whether the target battery cell is in a short circuit state or a micro short circuit state.

[0011] In some embodiments, the temperature in the first temperature interval is lower than the temperature in the second temperature interval.

[0012] In the above scheme, the electrical parameters of the battery cell in the micro-short circuit state are less than the second electrical parameter threshold at a lower temperature, and are greater than the second electrical parameter threshold at a higher temperature, so that it is possible to determine whether the target battery cell matches the micro-short circuit state based on the distribution of the electrical parameters in the low temperature range and the high temperature range.

[0013] In some embodiments, when the electrical parameters include resistance, the reference change trend corresponding to the micro-short circuit state includes a negative resistance change trend, a positive resistance change trend and a resistance stability trend in sequence during the temperature change process. The negative resistance change trend indicates that the resistance is negatively correlated with the temperature, and the resistance stability trend indicates that the resistance is in a stable state as the temperature changes.

[0014] In the above scheme, the battery cell in the micro-short circuit state has a negative resistance change trend, a positive resistance change trend and a resistance stability trend in sequence during the temperature change process, so that it is possible to determine whether the target battery cell matches the micro-short circuit state based on the change trend of the electrical parameters.

[0015] In some embodiments, multiple preset battery cell states also include a no short circuit state; wherein, the reference distribution characteristics corresponding to the no short circuit state include that the electrical parameters corresponding to different temperatures are all greater than a third electrical parameter threshold, and the first electrical parameter threshold, the second electrical parameter threshold, and the third electrical parameter threshold are the same; when the electrical parameters include resistance, the reference change trend corresponding to the no short circuit state includes a negative resistance change trend during the temperature change process, and the negative resistance change trend indicates that the resistance is negatively correlated with the temperature; when the electrical parameters include voltage, the reference change trend corresponding to the no short circuit state includes a positive voltage change trend during the temperature change process.

[0016] In the above solution, by setting the reference distribution characteristics and reference change trend corresponding to the non-short-circuit state, it is possible to detect whether the target battery cell is a non-short-circuit battery cell.

[0017] In some embodiments, from multiple preset cell states, a preset cell state whose reference parameter characteristics match the measured electrical parameters is selected as the cell state of the target cell, including: for each preset cell state, analyzing whether the measured electrical parameters match the reference parameter characteristics of the preset cell state, and obtaining a matching result of the preset cell state; and selecting the preset cell state whose matching result is a match as the cell state of the target cell.

[0018] In the above solution, the cell state of the target cell is determined by analyzing each preset cell state respectively.

[0019] In some embodiments, at least one preset battery cell state is a first preset battery cell state, and the reference parameter characteristics of the first preset battery cell state include a reference distribution characteristic, and the reference distribution characteristic characterizes that the electrical parameters in the preset battery cell state satisfy a preset size relationship with the electrical parameter threshold; analyzing whether the measured electrical parameters match the reference parameter characteristics of the preset battery cell state, and obtaining a matching result of the preset battery cell state, including: judging whether the measured electrical parameters and the electrical parameter threshold corresponding to the first preset battery cell state satisfy a preset size relationship, and obtaining a first judgment result; in response to the first judgment result satisfying the preset size relationship, determining that the measured electrical parameters match the reference distribution characteristics of the first preset battery cell state.

[0020] In the above scheme, by judging whether the measured electrical parameter and the corresponding electrical parameter threshold satisfy the preset size relationship, it can be determined whether the measured electrical parameter matches the reference distribution characteristics of the first preset battery cell state, thereby realizing the judgment of the battery cell state of the target battery cell.

[0021] In some embodiments, at least one preset battery cell state is a second preset battery cell state, and the reference parameter characteristics of the second preset battery cell state include a reference change trend, and the reference change trend characterizes the change trend of the electrical parameters in the preset battery cell state as the temperature changes; analyzing whether the measured electrical parameters match the reference parameter characteristics of the preset battery cell state, and obtaining a matching result of the preset battery cell state, including: judging whether the change trend of the measured electrical parameters as the temperature changes is consistent with the reference change trend corresponding to the second preset battery cell state, and obtaining a second judgment result; in response to the second judgment result being consistent, determining that the measured electrical parameters match the reference change trend of the second preset battery cell state.

[0022] In the above scheme, by comparing the changing trend of the measured electrical parameter with temperature with the reference changing trend, it can be determined whether the measured electrical parameter matches the reference changing trend of the second preset battery cell state, thereby realizing the judgment of the battery cell state of the target battery cell.

[0023] In some embodiments, the measured electrical parameters at each temperature include two types: voltage and resistance, at least one preset battery cell state is a third preset battery cell state, and the reference parameter characteristics of the third preset battery cell state include a reference distribution characteristic and a reference change trend; analyzing whether the measured electrical parameters match the reference parameter characteristics of the preset battery cell state to obtain a matching result of the preset battery cell state, including: for each type of measured electrical parameter, judging whether the measured electrical parameter matches the reference distribution characteristic of the third preset battery cell state, obtaining a distribution matching result of the measured electrical parameter and the third preset battery cell state, and judging whether the measured electrical parameter matches the reference change trend of the third preset battery cell state, obtaining a change matching result of the measured electrical parameter and the third preset battery cell state; in response to the distribution matching results and the change matching results of each type of measured electrical parameter and the third preset battery cell state being a match, determining that the matching result of the third preset battery cell state is a match.

[0024] In the above scheme, the distribution matching results and the variation matching results of various types of measured electrical parameters are analyzed respectively, and when the results are all matched, it is determined that the target cell matches the third preset cell state, and then the cell state of the target cell is determined.

[0025] In some embodiments, the plurality of preset battery cell states further include a non-short circuit state, the reference parameter characteristics of the non-short circuit state are reference distribution characteristics, and the reference parameter characteristics of the short circuit state and micro-short circuit state are reference change trends.

[0026] In the above scheme, the measured electrical parameters are matched with the reference distribution characteristics of the non-short circuit state and the reference change trends of the short circuit state and the micro-short circuit state to determine whether the target battery cell belongs to the non-short circuit state, the short circuit state and the micro-short circuit state.

[0027] In some embodiments, the measured electrical parameters at different temperatures include: multiple measured electrical parameters obtained by measuring the temperature of the target battery cell multiple times while controlling the temperature of the target battery cell to change linearly within a preset temperature range; or, the measured electrical parameters at different temperatures include measured electrical parameters corresponding to multiple preset temperatures within a preset temperature range, and the measured electrical parameters corresponding to each preset temperature are obtained by measuring the temperature of the target battery cell while controlling the temperature of the target battery cell to be a preset temperature.

[0028] In the above scheme, the temperature is controlled to change linearly within a preset temperature range or the temperature is controlled to be at a plurality of preset temperatures to obtain the measured electrical parameters at different temperatures, which can flexibly meet different application needs.

[0029] In some embodiments, the difference between two adjacent preset temperatures is a preset temperature difference.

[0030] In the above scheme, the difference between two adjacent preset temperatures is set as the preset temperature difference, so that the measured electrical parameters at the preset temperature can reflect the characteristics of the target battery cell, so as to improve the accuracy of the battery cell state detection of the target battery cell.

[0031] In some embodiments, the measured electrical parameter corresponding to the preset temperature is obtained by measuring the temperature of the target battery cell after the ambient temperature of the target battery cell is adjusted to a preset temperature and the target battery cell is waited for a preset time.

[0032] In the above scheme, by adjusting the ambient temperature and waiting for a preset time, the target battery cell is controlled to be at different temperatures to obtain the measured electrical parameters of the target battery cell at different temperatures.

[0033] The present application provides a detection device for internal short circuit of a battery cell, comprising a first acquisition module, a second acquisition module and a selection module. The first acquisition module is used to obtain the measured electrical parameters of the target battery cell at different temperatures, wherein the measured electrical parameters include at least one of voltage and resistance, and the reference parameter characteristics include at least one of reference distribution characteristics and reference change trends; the second acquisition module is used to obtain reference parameter characteristics corresponding to a plurality of preset battery cell states, wherein the plurality of preset battery cell states include a short circuit state and a micro short circuit state; the selection module is used to select a preset battery cell state whose reference parameter characteristics match the measured electrical parameters from a plurality of preset battery cell states as the battery cell state of the target battery cell.

[0034] 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 to implement the above-mentioned method for detecting an internal short circuit of any battery cell.

[0035] The present application provides a detection system for internal short circuit of a battery cell, the system comprising a temperature control box, a measuring device and equipment, the temperature control box is used to control the ambient temperature of the battery cell so that the target battery cell can be at different temperatures, the measuring device is used to measure the electrical parameters of the target battery cell, and the equipment is used to execute any of the above-mentioned methods for detecting internal short circuit of the battery cell.

[0036] 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 method for detecting an internal short circuit of any of the above-mentioned battery cells is implemented.

[0037] In the above scheme, the measured electrical parameters of the target battery cell at different temperatures are obtained. Compared with the judgment based on the electrical parameters at a single temperature, the measured electrical parameters at different temperatures can more comprehensively reflect the characteristics of the target battery cell, and are compared with the reference parameter characteristics of multiple preset battery cell states. The preset battery cell states include short circuit and micro short circuit, which can determine whether the target battery cell has a short circuit or micro short circuit, thereby improving the accuracy of internal short circuit detection.

[0038] 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

[0039] 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.

[0040] Figure 1 It is a flowchart of a method for detecting a short circuit inside a battery cell provided in some embodiments of the present application;

[0041] Figure 2 is a circuit diagram of multiple battery cells provided in some embodiments of the present application;

[0042] Figure 3 is a first schematic diagram of measuring electrical parameters of multiple battery cells provided by some embodiments of the present application;

[0043] Figure 4 is a second schematic diagram of measuring electrical parameters of multiple battery cells provided in some embodiments of the present application;

[0044] Figure 5 It is a schematic diagram of the framework of a device for detecting a short circuit inside a battery cell provided in some embodiments of the present application;

[0045] Figure 6 is a schematic diagram of a framework of an electronic device provided in some embodiments of the present application;

[0046] Figure 7 It is a schematic diagram of the framework of a battery cell internal short circuit detection system provided in some embodiments of the present application;

[0047] Figure 8 It is a schematic diagram of the framework of the computer-readable storage medium provided in some embodiments of the present application. DETAILED DESCRIPTION

[0048] The scheme of the embodiment of the present application is described in detail below in conjunction with the drawings of the specification.

[0049] 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.

[0050] 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.

[0051] The current method for detecting internal short circuits in battery cells usually measures the battery cells under the condition of constant temperature, and determines whether the battery cell is a short-circuited battery cell or a non-short-circuited battery cell based on the measured electrical parameters. However, the measured electrical parameters cannot accurately reflect the short circuit situation of the battery cell, and misjudgment often occurs, and the accuracy of internal short circuit detection of the battery cell is low. In the method for detecting internal short circuits in battery cells disclosed in the embodiment of the present application, measured electrical parameters of the target battery cell at different temperatures are obtained. Compared with judging by electrical parameters at a single temperature, the measured electrical parameters at different temperatures can more comprehensively reflect the characteristics of the target battery cell, and are compared with reference parameter characteristics of multiple preset battery cell states. The preset battery cell states include short circuit and micro short circuit, which can determine whether the target battery cell has a short circuit or micro short circuit, thereby improving the accuracy of internal short circuit detection.

[0052] The method for detecting an internal short circuit of a battery cell disclosed in the embodiment of the present application is used to detect whether an internal short circuit exists in a battery cell, wherein the type of battery cell to be detected is not limited.

[0053] See also Figure 1 , Figure 1 1 is a flow chart of a method for detecting a short circuit in a battery cell provided in some embodiments of the present application. Specifically, the method includes:

[0054] Step S110: obtaining measured electrical parameters of the target battery cell at different temperatures.

[0055] The measured electrical parameters include at least one of voltage and resistance.

[0056] In a specific application scenario, the measured voltage of the target battery cell at different temperatures is obtained. In a specific application scenario, the measured voltage and measured resistance of the target battery cell at different temperatures are obtained.

[0057] Step S120: obtaining reference parameter characteristics corresponding to a plurality of preset battery cell states respectively.

[0058] There is no necessary order restriction for executing step S110 and step S120.

[0059] The difference between different preset cell states is that the short circuit degree of the cell is different. Specifically, the multiple preset cell states include a short circuit state and a micro short circuit state, wherein the short circuit state refers to a complete short circuit state, and the micro short circuit state refers to a slight short circuit state.

[0060] It is understandable that for different short circuit types, the characteristics of the electrical parameters of the battery cells at different temperatures are different. The reference parameter characteristics can be used to characterize the characteristics of the electrical parameters of the battery cells at different temperatures, and different preset battery cell states correspond to their own reference parameter characteristics. The reference parameter characteristics can include at least one of the reference distribution characteristics and the reference change trend.

[0061] Among them, since the electrical parameters may include one or more categories, the reference parameter characteristics corresponding to the preset cell state may include reference parameter characteristics corresponding to the electrical parameters of one or more categories. For example, the reference parameter characteristics include characteristics characterizing the characteristics of the resistance of the cell at different temperatures, and also include characteristics characterizing the characteristics of the voltage of the cell at different temperatures.

[0062] In some embodiments, the plurality of preset battery cell states include a non-short circuit state, a short circuit state, and a micro-short circuit state.

[0063] See also Figure 2 , Figure 2 This is a circuit diagram of multiple battery cells provided in some embodiments of the present application.

[0064] Figure 2 Figure a shows a cell circuit diagram without short circuit. Figure 2 Figure b shows a short-circuit cell circuit diagram. Figure 2 Figure c shows a circuit diagram of a battery cell in a slightly short-circuit state.

[0065] in, Represents the ohmic impedance of the battery cell, represents the electrochemical reaction impedance, represents the diffusion impedance, Represents double layer capacitance. Figure 2 In the c Indicates short-circuit impedance.

[0066] The non-short-circuited cell circuit is the cell circuit. The short-circuited cell circuit can be simplified to a short line and the cell circuit in parallel. The micro-short-circuited cell circuit can be simplified to a micro-short-circuit resistor. Connect in parallel with the battery circuit.

[0067] When the state of the battery cell is between the complete short circuit state and the non-short circuit state, the battery cell has an internal short circuit, and the leakage rate can be used to indicate the degree of short circuit in the battery cell. The difference between the non-short circuit state, the short circuit state and the micro-short circuit state lies in the different degrees of short circuit. At the same temperature, the degree of internal short circuit of the battery cell is different, and the corresponding short circuit impedance has different resistance values. Micro short circuit refers to the existence of a slight short circuit, which is between the complete short circuit state and the non-short circuit state. The short circuit current threshold can be set or the micro short circuit can be defined according to the characteristics of the battery cell. For example, at room temperature, the short circuit point is small, the short circuit resistance is very large, and it is approximately an open circuit. The battery cell that is short-circuited under low temperature conditions can be considered a micro-short circuit battery cell.

[0068] Step S130: Selecting a preset cell state whose reference parameter characteristics match the measured electrical parameters from a plurality of preset cell states as the cell state of the target cell.

[0069] The measured electrical parameters of the target battery cell at different temperatures are compared with reference parameter characteristics corresponding to multiple preset battery cell states, and a matching preset battery cell state is selected as the battery cell state of the target battery cell.

[0070] The measured electrical parameters match the reference parameter characteristics of a preset battery cell state, indicating that the temperature variation characteristics of the target battery cell's electrical parameters are consistent with the characteristics represented by the reference parameter characteristics, and it can be determined that the target battery cell is in the corresponding preset battery cell state.

[0071] It is understood that, since the electrical parameters may include one or more categories, the measured electrical parameters of each category may be compared with reference parameter characteristics describing the electrical parameters of the corresponding category, for example, the reference parameter characteristics corresponding to the voltage may be compared with the measured voltage.

[0072] In some embodiments, different types of reference parameter features can describe the characteristics of changes in the electrical parameters of the battery cell with temperature from different perspectives.

[0073] The reference distribution feature may characterize that the electrical parameter in a preset cell state satisfies a preset magnitude relationship with the electrical parameter threshold. The reference change trend may characterize the change trend of the electrical parameter in a preset cell state as the temperature changes. The change trend of the electrical parameter as the temperature changes may be the change trend of the electrical parameter as the temperature rises, or the change trend of the electrical parameter as the temperature drops.

[0074] In some embodiments, the reference distribution characteristics corresponding to the short circuit state include that the electrical parameters corresponding to different temperatures are all less than a first electrical parameter threshold.

[0075] It is understandable that for voltage and resistance, the reference distribution characteristics of the short-circuit state are consistent, and the electrical parameters corresponding to different temperatures are all less than the threshold of the corresponding category. In a specific application scenario, when the electrical parameters include voltage, the reference distribution characteristics corresponding to the short-circuit state include that the voltage corresponding to different temperatures is less than the first voltage threshold, and when the electrical parameters include resistance, the resistance corresponding to different temperatures is less than the first resistance threshold. Exemplarily, the first voltage threshold corresponding to the short-circuit state can be 100mV, and the first resistance threshold can be 5kΩ.

[0076] In some embodiments, the reference distribution characteristics corresponding to the micro-short circuit state include that the electrical parameter in the first temperature interval is less than the second electrical parameter threshold, and the electrical parameter corresponding to the second temperature interval is greater than the second electrical parameter threshold.

[0077] In a specific application scenario, the temperature in the first temperature interval is lower than the temperature in the second temperature interval, the electrical parameter at low temperature is less than the second electrical parameter threshold, and the electrical parameter at high temperature is greater than the second electrical parameter threshold. Exemplarily, the second voltage threshold corresponding to the micro-short circuit state may be 100mV, and the second resistance threshold may be 100kΩ.

[0078] In some embodiments, the reference variation trend corresponding to the short circuit state includes that the electrical parameter is in a stable state during the temperature variation process, wherein the stable state may be that the electrical parameter remains unchanged or the variation range remains within a preset range.

[0079] In some embodiments, the electrical parameter may include resistance, and accordingly, the reference change trend corresponding to the micro-short circuit state may include a positive resistance change trend during the temperature change process, and the positive resistance change trend indicates that the resistance is positively correlated with the temperature. Specifically, the resistance decreases as the temperature decreases and increases as the temperature increases.

[0080] In some embodiments, the electrical parameter may include voltage, and accordingly, the reference change trend corresponding to the micro-short circuit state may include a positive voltage change trend and a voltage stability trend in sequence during the temperature change process. The positive voltage change trend indicates that the voltage is positively correlated with the temperature. Specifically, the voltage decreases as the temperature decreases and increases as the temperature increases. The voltage stability trend indicates that the voltage is in a stable state as the temperature changes.

[0081] It is understandable that the temperature change process can be a temperature rise process or a temperature drop process. In the two opposite temperature change situations, the order of the positive voltage change trend and the voltage stabilization trend is opposite. For example, in the process of temperature drop, the voltage first shows a positive voltage change trend and then shows a voltage stabilization trend. Correspondingly, in the process of temperature rise, the voltage first shows a voltage stabilization trend and then shows a positive voltage change trend.

[0082] In some embodiments, the electrical parameter may include resistance, and accordingly, the reference change trend corresponding to the micro-short circuit state includes a negative resistance change trend, a positive resistance change trend, and a resistance stability trend in sequence during the temperature change process.

[0083] The negative resistance change trend indicates that the resistance is negatively correlated with the temperature. Specifically, the resistance decreases with increasing temperature and increases with decreasing temperature. The stable resistance trend indicates that the resistance is in a stable state with temperature change. Specifically, the resistance remains unchanged with temperature change or the change amplitude remains within a preset range.

[0084] In a specific application scenario, during the temperature drop, the resistor first shows a negative resistance change trend, then shows a positive resistance change trend, and finally shows a stable resistance trend. Correspondingly, during the temperature rise, the resistor first shows a stable resistance trend, then shows a positive resistance change trend, and finally shows a negative resistance change trend.

[0085] In some embodiments, the plurality of preset battery cell states further include a no short circuit state, and the reference distribution characteristics corresponding to the no short circuit state may include that electrical parameters corresponding to different temperatures are all greater than a third electrical parameter threshold.

[0086] In a specific application scenario, different thresholds may be set for different preset battery cell states, and the first electrical parameter threshold, the second electrical parameter threshold, and the third electrical parameter threshold may be different.

[0087] In a specific application scenario, each preset cell state may be set with the same threshold value. The first electrical parameter threshold value, the second electrical parameter threshold value and the third electrical parameter threshold value may be the same.

[0088] In some embodiments, there are multiple categories of measured electrical parameters, and each category of measured electrical parameters has a corresponding threshold value.

[0089] In some embodiments, the plurality of preset cell states further include a non-short circuit state, the electrical parameter may include resistance, and accordingly, the reference change trend corresponding to the non-short circuit state includes a negative resistance change trend during the temperature change process.

[0090] In some embodiments, the plurality of preset cell states further include a non-short circuit state, the electrical parameter may include voltage, and accordingly, the reference change trend corresponding to the non-short circuit state includes a positive voltage change trend during the temperature change process.

[0091] The electrical parameter can be measured by controlling the temperature of the target battery cell and measuring it at different temperatures. In some embodiments, the target battery cell can be placed in a temperature control box, and the temperature of the environment in which the target battery cell is located can be adjusted by controlling the temperature of the temperature control box, thereby controlling the temperature of the target battery cell.

[0092] In a specific application scenario, a programmed temperature-controlled temperature box is used to control the temperature of the battery cell, and a multimeter or a voltage resistance meter is used to measure the electrical parameters of the battery cell. The electrical parameter measurement of the battery cell is carried out at room temperature through leads.

[0093] There are many ways to control the temperature of the target battery cell, which can be selected according to actual application needs. For example, a linear temperature sweep method or a transition temperature sweep method can be used.

[0094] In some embodiments, the measured electrical parameters at different temperatures include: a plurality of measured electrical parameters obtained by measuring the target battery cell multiple times while controlling the temperature of the target battery cell to change linearly within a preset temperature range. Exemplarily, the preset temperature range may be 25°C to -80°C, or 25°C to -100°C.

[0095] In some embodiments, the measured electrical parameters at different temperatures include measured electrical parameters corresponding to multiple preset temperatures within a preset temperature range, and the measured electrical parameters corresponding to each preset temperature are obtained by measuring the temperature of the target battery cell while controlling the temperature of the target battery cell to be the preset temperature.

[0096] In a specific application scenario, a plurality of preset temperatures are selected in advance within a preset temperature range, and the temperature of the target battery cell is controlled to be at the preset temperature respectively, and the electrical parameters of the target battery cell at the preset temperature are measured.

[0097] It is understandable that in order to accurately reflect the characteristics of the target chip, the number of preset temperatures can be set to be greater than the preset number threshold. In addition, the preset temperature can be selected according to the characteristics of the electrical parameters of multiple preset battery cell states at different temperatures, and the electrical parameters at the selected preset temperature can reflect the differences between different preset battery cell states. Exemplarily, multiple preset temperatures evenly distributed can be selected within the preset temperature range.

[0098] In one implementation scenario, the difference between two adjacent preset temperatures is a preset temperature difference.

[0099] In a specific application scenario, 5 preset temperatures are selected within the preset temperature range, and the difference between two adjacent preset temperatures is 30° C. For example, 25° C., -5° C., -35° C., -65° C., and -95° C. may be selected.

[0100] In some embodiments, the measured electrical parameter corresponding to the preset temperature is obtained by measuring the temperature of the target battery cell after adjusting the ambient temperature of the target battery cell to a preset temperature and waiting for a preset time.

[0101] In a specific application scenario, multiple preset temperatures are selected within the temperature range of T1-T2. At each preset temperature, it is necessary to stand for a preset time before measurement to stabilize the temperature and electrical parameters.

[0102] See also Figure 3 , Figure 3 This is a first schematic diagram of measuring electrical parameters of multiple battery cells provided in some embodiments of the present application.

[0103] Take the linear temperature sweep method as an example to illustrate. Figure 3 The horizontal axis of each figure is temperature, and the temperature decreases from left to right. Figure 3 a and d are the measured voltage and resistance collected from the non-short-circuited cell, respectively. Figure 3 b and e are the measured voltage and resistance collected from the short-circuited cell, respectively. Figure 3 In the figure, c and f are the measured voltage and measured resistance respectively collected from the micro-short-circuited battery cell.

[0104] For cells without short circuit, when the temperature is in the range of T1-T2, when the temperature T decreases linearly, the voltage also decreases linearly based on the linear relationship between voltage and temperature of the Nernst equation.

[0105] For a short-circuited cell, since the cell is short-circuited, when the temperature T decreases linearly within the temperature range of T1-T2, the voltage is zero.

[0106] For micro short circuit cells, the cell circuit simplifies the micro short circuit resistance When connected in parallel with the battery circuit, the temperature is high. The value is very large, and the resistance after parallel connection depends on the smaller battery circuit (which can be approximated as a non-short-circuit circuit). Therefore, when the temperature is in the higher temperature range T1-T3, the temperature drops linearly and the voltage also drops rapidly (the reason is As the temperature decreases, it tends to be more short-term characteristic) or decreases linearly. Figure 3 As shown in Figure c, the two lines in the temperature range of T1-T3 represent linear decline and accelerated decline respectively. When the temperature continues to drop to a critical temperature T3 (lower temperature segment), due to It decreases as the temperature drops. When the temperature reaches T3, Close to zero, resulting in a short circuit in the circuit, and the voltage signal is ~0 V. In a specific application scenario, T3 is between -50°C and -70°C, and the specific temperature is related to the electrolyte of the battery cell.

[0107] For cells without short circuits, when the temperature T decreases linearly within the range of T1-T2, the electrochemical impedance increases rapidly (the growth curve varies depending on the cell chemical system, and the three curves in the figure represent the growth curves of different chemical systems).

[0108] For a short-circuited cell, since the cell is short-circuited, when the temperature T decreases linearly within the temperature range of T1-T2, the resistance is zero.

[0109] For micro short circuit cells, the cell circuit is simplified to micro short circuit resistors. In parallel with the battery circuit, when the temperature is in the higher temperature range T1-T4, due to The resistance value is very large (the reason is that the short-circuit point is small when the short circuit is micro-short-circuited at this temperature). The resistance after parallel connection depends on the smaller battery cell loop (which can be approximated as a circuit without short circuit). When the temperature is in the higher temperature range T1-T4, the temperature drops linearly and the resistance increases rapidly (when the temperature decreases, the electrochemical impedance increases significantly). When the temperature is in the lower temperature range T4-T2, due to The resistance of the parallel connection depends on the smaller loop. Therefore, when the temperature is in the lower temperature range T4-T2, the temperature drops linearly and the resistance gradually decreases (the reduction curve varies according to the different chemical systems of the battery cell, and the three curves in the figure represent the curves of different chemical systems). When it drops to a certain critical temperature T5, the resistance tends to be stable and small. For example, the resistance of a normal battery cell is >100MΩ. Below the critical temperature T5, the resistance ranges from 0-100kΩ, and the resistance value depends on the degree of short circuit in the battery cell.

[0110] In a specific application scenario, T4 is between 10°C and -40°C, and T5 is between -50°C and -70°C. The specific temperature is related to the electrolyte of the battery cell.

[0111] The above method can obtain the complete relationship between voltage signal and current signal and temperature in the temperature range of T1-T2, but it takes a relatively long time. In order to save test time, a transition temperature scan method can be used.

[0112] See also Figure 4 , Figure 4 This is a second schematic diagram of measuring electrical parameters of multiple battery cells provided in some embodiments of the present application.

[0113] Take the transition temperature scanning method as an example to illustrate. Figure 4 The horizontal axis of each figure is temperature, and the temperature decreases from left to right. Figure 4 a and d are the measured voltage and resistance collected from the non-short-circuited cell, respectively. Figure 4 b and e are the measured voltage and resistance collected from the short-circuited cell, respectively. Figure 4 Where c and f are the measured voltage and resistance collected from the micro-short-circuited cell respectively. The parameter change rules can be referred to Figure 3 Related description.

[0114] Specifically, within the temperature range of T1-T2, 5 temperature points are selected. Before testing at each temperature point, it is necessary to stand still for a period of time to ensure that the battery cell temperature, voltage signal and resistance signal are stable.

[0115] In some embodiments, selecting a preset cell state whose reference parameter characteristics match the measured electrical parameters from a plurality of preset cell states as the cell state of the target cell may include: for each preset cell state, analyzing whether the measured electrical parameters match the reference parameter characteristics of the preset cell state, and obtaining a matching result of the preset cell state. Selecting the preset cell state whose matching result is a match as the cell state of the target cell.

[0116] Among them, the measured electrical parameters measured for the target battery cell are compared with the reference parameter characteristics of each preset battery cell state. In some embodiments, the measured electrical parameters include at least one of voltage and resistance. The reference parameter characteristics may include characteristics that describe the characteristics of the corresponding category parameters. For each type of measured electrical parameter, it can be compared with the reference parameter characteristics that describe the characteristics of the corresponding category parameters. Exemplarily, the measured voltage is compared with the reference parameter characteristics that describe the voltage, and the measured resistance is compared with the reference parameter characteristics that describe the resistance.

[0117] In some embodiments, analyzing whether the measured electrical parameter matches the reference parameter feature may be comparing the measured electrical parameter with at least one category of reference parameter features. Exemplarily, the measured electrical parameter is compared with the reference distribution feature alone, or the measured electrical parameter is compared with the reference distribution feature and the reference change trend respectively.

[0118] In some embodiments, at least one preset battery cell state is a first preset battery cell state, and the reference parameter characteristics of the first preset battery cell state may include reference distribution characteristics. Analyzing whether the measured electrical parameters match the reference parameter characteristics of the preset battery cell state to obtain the matching result of the preset battery cell state may include: analyzing whether the measured electrical parameters match the reference distribution characteristics of the first preset battery cell state, specifically, judging whether the measured electrical parameters and the electrical parameter thresholds corresponding to the first preset battery cell state satisfy a preset size relationship to obtain a first judgment result. The first judgment result may be satisfied or not satisfied. In response to the first judgment result satisfying the preset size relationship, it is determined that the measured electrical parameters match the reference distribution characteristics of the first preset battery cell state; in response to the first judgment result not satisfying the preset size relationship, the measured electrical parameters do not match the reference distribution characteristics of the first preset battery cell state.

[0119] In one implementation scenario, the type of the measured electrical parameter is one category, and the measured electrical parameter is compared with the electrical parameter threshold of the category corresponding to the first preset battery cell state to determine whether the preset size relationship is satisfied.

[0120] In one implementation scenario, there are multiple types of measured electrical parameters, such as voltage and resistance. One or more types of measured electrical parameters are compared with the electrical parameter thresholds of the corresponding categories of the first preset battery cell state to determine whether the corresponding preset size relationship is satisfied, and one or more first judgment results are obtained. In response to the inconsistency of the first judgment result, it is determined that the measured electrical parameters do not match the reference distribution characteristics of the first preset battery cell state.

[0121] In some embodiments, at least one preset battery cell state is a second preset battery cell state, and the reference parameter characteristics of the second preset battery cell state may include a reference change trend. Analyzing whether the measured electrical parameters match the reference parameter characteristics of the preset battery cell state to obtain the matching result of the preset battery cell state may include: analyzing whether the measured electrical parameters match the reference change trend of the second preset battery cell state, specifically, judging whether the change trend of the measured electrical parameters with temperature changes is consistent with the reference change trend corresponding to the second preset battery cell state, and obtaining a second judgment result. The second judgment result may be consistent or inconsistent. In response to the second judgment result being consistent, it is determined that the measured electrical parameters match the reference change trend of the second preset battery cell state, and in response to the second judgment result being inconsistent, it is determined that the measured electrical parameters do not match the reference change trend of the second preset battery cell state.

[0122] In some embodiments, at least one preset cell state is a third preset cell state, and the reference parameter characteristics of the third preset cell state may include reference distribution characteristics and reference change trends. Analyzing whether the measured electrical parameters match the reference parameter characteristics of the preset cell state, and obtaining the matching result of the preset cell state may include: judging whether the measured electrical parameters match the reference distribution characteristics of the third preset cell state, and determining the distribution matching result of the measured electrical parameters and the third preset cell state; and judging whether the measured electrical parameters match the reference change trend of the third preset cell state, and determining the change matching result of the measured electrical parameters and the third preset cell state; in response to the distribution matching result and the change matching result both matching, determining that the matching result between the measured electrical parameters and the third preset cell state is a match, and the matching result of the third preset cell state is a match.

[0123] Furthermore, when the measured electrical parameters at each temperature include two types, voltage and resistance, each type of measured electrical parameter is judged separately to obtain distribution matching results and change matching results of each type of measured electrical parameter. In response to the distribution matching results and change matching results of each type of measured electrical parameter being a match, the matching result of the third preset battery cell state is determined to be a match.

[0124] In some embodiments, for a certain preset cell state, a distribution matching result can also be obtained by separate analysis, and whether the measured electrical parameters of the target cell match the preset cell state can be determined based on the distribution matching result.

[0125] In some embodiments, for a preset cell state, a change matching result may be separately analyzed to obtain a distribution matching result, and whether the measured electrical parameters of the target cell match the preset cell state is determined based on the distribution matching result.

[0126] In some embodiments, all preset cell states may be subjected to the same type of analysis steps. For example, for each preset cell state, a distribution matching result and a variation matching result are analyzed separately to determine whether the target cell matches the preset cell state.

[0127] In some embodiments, different preset battery cells may also perform different types of analysis steps. For example, for the no short circuit state, only the distribution matching result may be analyzed to determine whether the target battery cell matches the no short circuit state. For the short circuit state and micro short circuit state, the distribution matching result and the change matching result may be analyzed respectively to determine whether the target battery cell matches the preset battery cell state.

[0128] In some embodiments, for all preset cell states, the same category of measured electrical parameters may be analyzed. In some embodiments, for different preset cell states, different categories of measured electrical parameters may be analyzed.

[0129] In a specific application scenario, multiple preset cell states include a non-short circuit state, a short circuit state, and a micro-short circuit state. For the non-short circuit state, a reference distribution feature is used as a reference parameter feature. For the short circuit state and the micro-short circuit state, a reference change trend is used as a reference parameter feature.

[0130] In a specific application scenario, the measured electrical parameters of the target battery cell at different temperatures are compared with the reference distribution characteristics of the non-short-circuit state, and the measured electrical parameters of the target battery cell at different temperatures are compared with the reference change trends of the short-circuit state and the micro-short-circuit state. Figure 3 As shown in the figure, since the electrical parameters of the non-short circuit state are all greater than the corresponding electrical parameter thresholds, the reference distribution characteristics can clearly distinguish the non-short circuit state, so the reference distribution characteristics are used as the reference parameter characteristics of the non-short circuit state. There are significant change trends in the short circuit state / micro-short circuit state, and the reference change trend can clearly distinguish the short circuit state / micro-short circuit state, so the reference change trend is used as the reference parameter characteristic.

[0131] See also Figure 5 , Figure 5 It is a schematic diagram of the framework of a device for detecting internal short circuit of a battery cell provided in some embodiments of the present application.

[0132] The detection device 50 for internal short circuit of a battery cell includes a first acquisition module 51, a second acquisition module 52 and a selection module 53. The first acquisition module 51 is used to acquire the measured electrical parameters of the target battery cell at different temperatures, wherein the measured electrical parameters include at least one of voltage and resistance; the second acquisition module 52 is used to acquire reference parameter characteristics corresponding to a plurality of preset battery cell states, wherein the plurality of preset battery cell states include a short circuit state and a micro short circuit state, and the reference parameter characteristics include at least one of a reference distribution characteristic and a reference change trend; the selection module 53 is used to select a preset battery cell state whose reference parameter characteristics match the measured electrical parameters from a plurality of preset battery cell states as the battery cell state of the target battery cell.

[0133] In the above scheme, the measured electrical parameters of the target battery cell at different temperatures are obtained. Compared with the judgment based on the electrical parameters at a single temperature, the measured electrical parameters at different temperatures can more comprehensively reflect the characteristics of the target battery cell, and are compared with the reference parameter characteristics of multiple preset battery cell states. The preset battery cell states include short circuit and micro short circuit, which can determine whether the target battery cell has a short circuit or micro short circuit, thereby improving the accuracy of internal short circuit detection.

[0134] In some embodiments, the reference distribution characteristic characterizes that the electrical parameter in a preset battery cell state satisfies a preset size relationship with the electrical parameter threshold, and the reference change trend characterizes the change trend of the electrical parameter in a preset battery cell state with temperature change, and the temperature change is temperature drop or temperature rise.

[0135] In the above scheme, two types of reference parameter characteristics are set for selection, which reflect the characteristics of the battery cell under the preset battery cell state from different angles, and can more flexibly realize the detection of internal short circuit of the battery cell.

[0136] In some embodiments, the reference distribution characteristics corresponding to the short circuit state include that the electrical parameters corresponding to different temperatures are all less than the first electrical parameter threshold; the reference distribution characteristics corresponding to the micro short circuit state include that the electrical parameters corresponding to the first temperature interval are less than the second electrical parameter threshold, and the electrical parameters corresponding to the second temperature interval are greater than the second electrical parameter threshold; the reference change trend corresponding to the short circuit state includes that the electrical parameters are in a stable state during the temperature change process, and the stable state is that the electrical parameters remain unchanged or the change amplitude remains within a preset range; when the electrical parameters include resistance, the reference change trend corresponding to the micro short circuit state includes the existence of a forward resistance change trend during the temperature change process, and the forward resistance change trend indicates that the resistance is positively correlated with the temperature; when the electrical parameters include voltage, the reference change trend corresponding to the micro short circuit state includes the existence of a forward voltage change trend and a voltage stabilization trend in sequence during the temperature change process, the forward voltage change trend indicates that the voltage is positively correlated with the temperature, and the voltage stabilization trend indicates that the voltage is in a stable state as the temperature changes.

[0137] In the above scheme, reference distribution characteristics corresponding to the short circuit state and the micro short circuit state are set respectively, and reference change trends of the short circuit state and the micro short circuit state are provided, and two types of reference parameter characteristics are provided to determine whether the target battery cell is in a short circuit state or a micro short circuit state.

[0138] In some embodiments, the temperature in the first temperature interval is lower than the temperature in the second temperature interval.

[0139] In the above scheme, the electrical parameters of the battery cell in the micro-short circuit state are less than the second electrical parameter threshold at a lower temperature, and are greater than the second electrical parameter threshold at a higher temperature, so that it is possible to determine whether the target battery cell matches the micro-short circuit state based on the distribution of the electrical parameters in the low temperature range and the high temperature range.

[0140] In some embodiments, when the electrical parameters include resistance, the reference change trend corresponding to the micro-short circuit state includes a negative resistance change trend, a positive resistance change trend and a resistance stability trend in sequence during the temperature change process. The negative resistance change trend indicates that the resistance is negatively correlated with the temperature, and the resistance stability trend indicates that the resistance is in a stable state as the temperature changes.

[0141] In the above scheme, the battery cell in the micro-short circuit state has a negative resistance change trend, a positive resistance change trend and a resistance stability trend in sequence during the temperature change process, so that it is possible to determine whether the target battery cell matches the micro-short circuit state based on the change trend of the electrical parameters.

[0142] In some embodiments, multiple preset battery cell states also include a no short circuit state; wherein, the reference distribution characteristics corresponding to the no short circuit state include that the electrical parameters corresponding to different temperatures are all greater than a third electrical parameter threshold, and the first electrical parameter threshold, the second electrical parameter threshold, and the third electrical parameter threshold are the same; when the electrical parameters include resistance, the reference change trend corresponding to the no short circuit state includes a negative resistance change trend during the temperature change process, and the negative resistance change trend indicates that the resistance is negatively correlated with the temperature; when the electrical parameters include voltage, the reference change trend corresponding to the no short circuit state includes a positive voltage change trend during the temperature change process.

[0143] In the above solution, by setting the reference distribution characteristics and reference change trend corresponding to the non-short-circuit state, it is possible to detect whether the target battery cell is a non-short-circuit battery cell.

[0144] In some embodiments, the selection module 53 is used to select a preset cell state whose reference parameter characteristics match the measured electrical parameters from multiple preset cell states as the cell state of the target cell, specifically including: for each preset cell state, analyzing whether the measured electrical parameters match the reference parameter characteristics of the preset cell state, and obtaining a matching result of the preset cell state; and selecting the preset cell state whose matching result is a match as the cell state of the target cell.

[0145] In the above solution, the cell state of the target cell is determined by analyzing each preset cell state respectively.

[0146] In some embodiments, at least one preset battery cell state is a first preset battery cell state, and the reference parameter characteristics of the first preset battery cell state include a reference distribution characteristic, and the reference distribution characteristic characterizes that the electrical parameters in the preset battery cell state satisfy a preset size relationship with the electrical parameter threshold value; the selection module 53 is used to analyze whether the measured electrical parameters match the reference parameter characteristics of the preset battery cell state, and obtain a matching result of the preset battery cell state, specifically including: judging whether the measured electrical parameters and the electrical parameter threshold value corresponding to the first preset battery cell state satisfy a preset size relationship, and obtaining a first judgment result; in response to the first judgment result satisfying the preset size relationship, determining that the measured electrical parameters match the reference distribution characteristics of the first preset battery cell state.

[0147] In the above scheme, by judging whether the measured electrical parameter and the corresponding electrical parameter threshold satisfy the preset size relationship, it can be determined whether the measured electrical parameter matches the reference distribution characteristics of the first preset battery cell state, thereby realizing the judgment of the battery cell state of the target battery cell.

[0148] In some embodiments, at least one preset battery cell state is a second preset battery cell state, and the reference parameter characteristics of the second preset battery cell state include a reference change trend, and the reference change trend characterizes the change trend of the electrical parameters in the preset battery cell state with temperature changes; the selection module 53 is used to analyze whether the measured electrical parameters match the reference parameter characteristics of the preset battery cell state, and obtain the matching result of the preset battery cell state, specifically including: judging whether the change trend of the measured electrical parameters with temperature changes is consistent with the reference change trend corresponding to the second preset battery cell state, and obtaining a second judgment result; in response to the second judgment result being consistent, determining that the measured electrical parameters match the reference change trend of the second preset battery cell state.

[0149] In the above scheme, by comparing the changing trend of the measured electrical parameter with temperature with the reference changing trend, it can be determined whether the measured electrical parameter matches the reference changing trend of the second preset battery cell state, thereby realizing the judgment of the battery cell state of the target battery cell.

[0150] In some embodiments, the measured electrical parameters at each temperature include two types: voltage and resistance, at least one preset battery cell state is a third preset battery cell state, and the reference parameter characteristics of the third preset battery cell state include a reference distribution characteristic and a reference change trend; the selection module 53 is used to analyze whether the measured electrical parameters match the reference parameter characteristics of the preset battery cell state, and obtain the matching result of the preset battery cell state, specifically including: for each type of measured electrical parameter, judging whether the measured electrical parameter matches the reference distribution characteristic of the third preset battery cell state, and obtaining the distribution matching result of the measured electrical parameter and the third preset battery cell state, and judging whether the measured electrical parameter matches the reference change trend of the third preset battery cell state, and obtaining the change matching result of the measured electrical parameter and the third preset battery cell state; in response to the distribution matching results and the change matching results of each type of measured electrical parameter and the third preset battery cell state being a match, determining that the matching result of the third preset battery cell state is a match.

[0151] In the above scheme, the distribution matching results and the variation matching results of various types of measured electrical parameters are analyzed respectively, and when the results are all matched, it is determined that the target cell matches the third preset cell state, and then the cell state of the target cell is determined.

[0152] In some embodiments, the plurality of preset battery cell states also include a non-short circuit state, the reference parameter characteristics of the non-short circuit state are reference distribution characteristics, and the reference parameter characteristics of the short circuit state and micro-short circuit state are reference change trends.

[0153] In the above scheme, the measured electrical parameters are matched with the reference distribution characteristics of the non-short circuit state and the reference change trends of the short circuit state and the micro-short circuit state to determine whether the target battery cell belongs to the non-short circuit state, the short circuit state and the micro-short circuit state.

[0154] In some embodiments, the measured electrical parameters at different temperatures include: multiple measured electrical parameters obtained by measuring the temperature of the target battery cell multiple times while controlling the temperature of the target battery cell to change linearly within a preset temperature range; or, the measured electrical parameters at different temperatures include measured electrical parameters corresponding to multiple preset temperatures within a preset temperature range, and the measured electrical parameters corresponding to each preset temperature are obtained by measuring the temperature of the target battery cell while controlling the temperature of the target battery cell to be a preset temperature.

[0155] In the above scheme, the temperature is controlled to change linearly within a preset temperature range or the temperature is controlled to be at a plurality of preset temperatures to obtain the measured electrical parameters at different temperatures, which can flexibly meet different application needs.

[0156] In some embodiments, the difference between two adjacent preset temperatures is a preset temperature difference.

[0157] In the above scheme, the difference between two adjacent preset temperatures is set as the preset temperature difference, so that the measured electrical parameters at the preset temperature can reflect the characteristics of the target battery cell, so as to improve the accuracy of the battery cell state detection of the target battery cell.

[0158] In some embodiments, the measured electrical parameter corresponding to the preset temperature is obtained by measuring the temperature of the target battery cell after the ambient temperature of the target battery cell is adjusted to a preset temperature and the target battery cell is waited for a preset time.

[0159] In the above scheme, by adjusting the ambient temperature and waiting for a preset time, the target battery cell is controlled to be at different temperatures to obtain the measured electrical parameters of the target battery cell at different temperatures.

[0160] 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.

[0161] The electronic device 60 includes a memory 61 and a processor 62 coupled to each other, and the processor 62 is used to execute program instructions stored in the memory 61 to implement the above-mentioned method for detecting an internal short circuit of any battery cell. In a specific implementation scenario, the electronic device 60 may include but is not limited to: a microcomputer, a server, and in addition, the electronic device 60 may also include a mobile device such as a laptop computer and a tablet computer, which is not limited here.

[0162] Specifically, the processor 62 is used to control itself and the memory 61 to implement the above-mentioned detection method of internal short circuit of any 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.

[0163] See also Figure 7 , Figure 7 It is a schematic diagram of the framework of a battery cell internal short circuit detection system provided in some embodiments of the present application.

[0164] The detection system 70 for internal short circuit of battery cells includes a temperature control box 71, a measuring device 72 and equipment 73. The temperature control box 71 is used to control the ambient temperature of the battery cells so that the target battery cells are at different temperatures; the measuring device 72 is used to measure the electrical parameters of the target battery cells; and the equipment 73 is used to execute any of the above-mentioned methods for detecting internal short circuit of battery cells.

[0165] In some embodiments, the temperature control box 71 is a programmable temperature control box. In some embodiments, the measuring device 72 is a multimeter or a voltage resistance meter.

[0166] See also Figure 8 , Figure 8 It is a schematic diagram of the framework of the computer-readable storage medium provided in some embodiments of the present application.

[0167] The computer-readable storage medium 80 stores program instructions 81 that can be executed by a processor. When the program instructions 81 are executed by the processor, they are used to implement any of the above-mentioned methods for detecting an internal short circuit of a battery cell.

[0168] 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.

[0169] 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.

[0170] 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 detecting an internal short circuit of a battery cell, characterized in that: The method comprises: Acquiring measured electrical parameters of the target battery cell at different temperatures, wherein the measured electrical parameters include at least one of voltage and resistance; and Obtain reference parameter characteristics corresponding to a plurality of preset battery cell states, wherein the plurality of preset battery cell states include a short circuit state and a micro short circuit state, and the reference parameter characteristics include at least one of a reference distribution characteristic and a reference change trend, the reference distribution characteristic characterizes that an electrical parameter in the preset battery cell state satisfies a preset magnitude relationship with an electrical parameter threshold, and the reference change trend characterizes a change trend of the electrical parameter in the preset battery cell state with temperature change, wherein the temperature change is a temperature drop or a temperature rise; the reference distribution characteristic corresponding to the short circuit state includes that electrical parameters corresponding to different temperatures are all less than a first electrical parameter threshold; the reference distribution characteristic corresponding to the micro short circuit state includes that an electrical parameter corresponding to a first temperature interval is less than a second electrical parameter threshold, and an electrical parameter corresponding to a second temperature interval is greater than the second electrical parameter threshold; From the plurality of preset cell states, a preset cell state whose reference parameter feature matches the measured electrical parameter is selected as the cell state of the target cell.

2. The method according to claim 1, characterized in that The reference change trend corresponding to the short-circuit state includes that the electrical parameter is in a stable state during the temperature change process, and the stable state is that the electrical parameter remains unchanged or the change amplitude remains within a preset range; In the case where the electrical parameter includes resistance, the reference change trend corresponding to the micro-short circuit state includes a forward resistance change trend during a temperature change process, and the forward resistance change trend indicates that the resistance is positively correlated with the temperature; When the electrical parameter includes voltage, the reference change trend corresponding to the micro-short circuit state includes a forward voltage change trend and a voltage stability trend in sequence during the temperature change process, the forward voltage change trend indicates that the voltage is positively correlated with the temperature, and the voltage stability trend indicates that the voltage is in the stable state as the temperature changes.

3. The method according to claim 2, characterized in that The temperature in the first temperature interval is lower than the temperature in the second temperature interval; And / or, in the case where the electrical parameter includes resistance, the reference change trend corresponding to the micro-short circuit state includes a negative resistance change trend, a positive resistance change trend and a resistance stability trend in sequence during a temperature change process, wherein the negative resistance change trend indicates that the resistance is negatively correlated with the temperature, and the resistance stability trend indicates that the resistance is in the stable state as the temperature changes; And / or, the multiple preset battery cell states also include a no short circuit state; wherein the reference distribution characteristics corresponding to the no short circuit state include that the electrical parameters corresponding to different temperatures are all greater than a third electrical parameter threshold, and the first electrical parameter threshold, the second electrical parameter threshold, and the third electrical parameter threshold are the same; when the electrical parameter includes resistance, the reference change trend corresponding to the no short circuit state includes a negative resistance change trend during the temperature change process, and the negative resistance change trend indicates that the resistance is negatively correlated with the temperature; when the electrical parameter includes voltage, the reference change trend corresponding to the no short circuit state includes a positive voltage change trend during the temperature change process.

4. The method according to claim 1, characterized in that: The step of selecting, from the plurality of preset cell states, a preset cell state whose reference parameter characteristic matches the measured electrical parameter as the cell state of the target cell includes: For each of the preset cell states, analyzing whether the measured electrical parameters match the reference parameter characteristics of the preset cell state, and obtaining a matching result of the preset cell state; The preset cell state for which the matching result is a match is selected as the cell state of the target cell.

5. The method according to claim 4, characterized in that At least one of the preset battery cell states is a first preset battery cell state, and the reference parameter characteristics of the first preset battery cell state include the reference distribution characteristics; The analyzing whether the measured electrical parameter matches the reference parameter feature of the preset battery cell state to obtain a matching result of the preset battery cell state includes: Determine whether the measured electrical parameter and the electrical parameter threshold corresponding to the first preset battery cell state satisfy a preset magnitude relationship, and obtain a first determination result; In response to the first judgment result satisfying the preset magnitude relationship, it is determined that the measured electrical parameter matches the reference distribution characteristic of the first preset battery cell state.

6. The method according to claim 4, characterized in that At least one of the preset battery cell states is a second preset battery cell state, and the reference parameter characteristics of the second preset battery cell state include the reference change trend; The analyzing whether the measured electrical parameter matches the reference parameter feature of the preset battery cell state to obtain a matching result of the preset battery cell state includes: Determine whether the variation trend of the measured electrical parameter with temperature is consistent with the reference variation trend corresponding to the second preset battery cell state, and obtain a second determination result; In response to the second judgment result being consistent, it is determined that the measured electrical parameter matches the reference change trend of the second preset battery cell state.

7. The method according to claim 4, characterized in that The measured electrical parameters at each temperature include two types: voltage and resistance, at least one of the preset battery cell states is a third preset battery cell state, and the reference parameter characteristics of the third preset battery cell state include the reference distribution characteristics and the reference change trend; The analyzing whether the measured electrical parameter matches the reference parameter feature of the preset battery cell state to obtain a matching result of the preset battery cell state includes: For each type of measured electrical parameter, determine whether the measured electrical parameter matches the reference distribution feature of the third preset battery cell state, and obtain a distribution matching result of the measured electrical parameter and the third preset battery cell state, and determine whether the measured electrical parameter matches the reference change trend of the third preset battery cell state, and obtain a change matching result of the measured electrical parameter and the third preset battery cell state; In response to the distribution matching results and the variation matching results of various types of the measured electrical parameters and the third preset battery cell state being matched, it is determined that the matching result of the third preset battery cell state is matched.

8. The method according to claim 4, characterized in that The multiple preset battery cell states also include a non-short-circuit state, the reference parameter characteristics of the non-short-circuit state are the reference distribution characteristics, and the reference parameter characteristics of the short-circuit state and the micro-short-circuit state are the reference change trends.

9. The method according to claim 1, characterized in that: The measured electrical parameters at different temperatures include: a plurality of measured electrical parameters obtained by measuring the temperature of the target battery cell multiple times in the process of controlling the temperature of the target battery cell to change linearly within a preset temperature range; or, The measured electrical parameters at different temperatures include measured electrical parameters corresponding to multiple preset temperatures within the preset temperature range, and the measured electrical parameters corresponding to each preset temperature are obtained by measuring the temperature of the target battery cell while controlling the temperature of the target battery cell to be the preset temperature.

10. The method according to claim 9, characterized in that The difference between two adjacent preset temperatures is a preset temperature difference; And / or, the measured electrical parameter corresponding to the preset temperature is obtained by measuring the temperature of the target battery cell after the ambient temperature of the target battery cell is adjusted to the preset temperature and the temperature is measured for a preset period of time.

11. A device for detecting internal short circuit of a battery cell, characterized in that: include: A first acquisition module, used to acquire measured electrical parameters of the target battery cell at different temperatures, wherein the measured electrical parameters include at least one of voltage and resistance; A second acquisition module is used to obtain reference parameter characteristics corresponding to multiple preset battery cell states, wherein the multiple preset battery cell states include a short circuit state and a micro short circuit state, and the reference parameter characteristics include at least one of a reference distribution characteristic and a reference change trend, the reference distribution characteristic characterizes that the electrical parameter in the preset battery cell state satisfies a preset size relationship with the electrical parameter threshold, and the reference change trend characterizes the change trend of the electrical parameter in the preset battery cell state with temperature change, and the temperature change is a temperature drop or a temperature rise; the reference distribution characteristic corresponding to the short circuit state includes that the electrical parameters corresponding to different temperatures are all less than a first electrical parameter threshold; the reference distribution characteristic corresponding to the micro short circuit state includes that the electrical parameter corresponding to the first temperature interval is less than the second electrical parameter threshold, and the electrical parameter corresponding to the second temperature interval is greater than the second electrical parameter threshold; The selection module is used to select a preset cell state whose reference parameter feature matches the measured electrical parameter from the multiple preset cell states as the cell state of the target cell.

12. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory stores program instructions, and when the program instructions are executed by the processor, the method according to any one of claims 1 to 10 is implemented.

13. A detection system for internal short circuit of a battery cell, characterized in that: The system includes a temperature control box, a measuring device and equipment, wherein the temperature control box is used to control the ambient temperature of the battery cell so that the target battery cell can be at different temperatures, the measuring device is used to measure the electrical parameters of the target battery cell, and the equipment is used to execute the method described in any one of claims 1 to 10.

14. A computer-readable storage medium having program instructions stored thereon, characterized in that: When the program instructions are executed by a processor, the method according to any one of claims 1 to 10 is implemented.

Images