Battery short circuit detection method and device, storage medium and power utilization device

Abstract

The invention discloses a battery short circuit detection method and device, a storage medium and a power utilization device, and the method comprises the steps: determining the short circuit state of a battery unit according to the change value of the real-time electrochemical data of the battery unit, by adopting the method, the short-circuit fault of the battery unit can be identified at the short-circuit moment of the battery unit, so that the problem of hysteresis of short-circuit fault identification of the battery unit is avoided.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a battery short circuit detection method, a battery short circuit detection device, a non-volatile computer-readable storage medium and an electric device. Background Art

[0002] In the related art, after a short circuit occurs in a battery cell, the electrochemical parameters of the short-circuited battery cell change based on the accumulation of short-circuit leakage current, and then the electrochemical parameters of the short-circuited battery cell are used to determine whether an internal short circuit occurs in the battery cell. This short circuit detection method can detect the internal short circuit of the battery cell only after the short circuit occurs in the battery cell and the restriction conditions are met, which leads to a lag problem in the identification of the internal short circuit of the battery cell. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the first purpose of the present invention is to propose a battery short circuit detection method, which can identify the short circuit fault of the battery cell at the moment of the short circuit of the battery cell, thereby avoiding the problem of hysteresis in the identification of the short circuit fault of the battery cell.

[0004] A second objective of the present invention is to provide a battery short circuit detection device.

[0005] A third objective of the present invention is to provide a non-volatile computer-readable storage medium.

[0006] A fourth object of the present invention is to provide an electrical device.

[0007] In order to solve the above problem, a first aspect of an embodiment of the present invention provides a battery short circuit detection method, comprising: determining the short circuit state of the battery cell according to a change value of real-time electrochemical data of the battery cell.

[0008] According to the battery short circuit detection method of the embodiment of the present invention, based on the characteristic of sudden change of real-time electrochemical data when a short circuit occurs in a battery cell, the short circuit state of the battery cell is detected by the change value, i.e., increase or decrease value, of the real-time electrochemical data generated by the battery cell during operation. For example, whether an internal short circuit occurs in the battery cell is detected by the change value, i.e., increase or decrease value, of the real-time electrochemical data of the battery cell. Therefore, compared with the prior art in which the electrochemical parameters of the short-circuited cell are changed by the accumulation of short-circuit leakage current and then the electrochemical parameters of the short-circuited cell are used to determine whether an internal short circuit occurs in the battery cell, in the present application, whether an internal short circuit occurs in the battery cell is detected by the change value of the real-time electrochemical data, and there is no need to trigger the internal short circuit fault detection of the battery cell after the restriction conditions are met after the short circuit fault occurs in the battery cell, thereby being able to detect the internal short circuit fault of the battery cell in time, thereby avoiding the problem of hysteresis in the identification of the internal short circuit fault of the battery cell.

[0009] In some embodiments, the change value of the real-time electrochemical data includes a voltage change rate and a current change rate; determining the short-circuit state of the battery cell according to the change value of the real-time electrochemical data of the battery cell includes: if the voltage change rate is greater than a first voltage change threshold and the current change rate is less than a current change threshold, determining that the battery cell is short-circuited.

[0010] In some embodiments, determining the short circuit state of the battery cell based on the change value of the real-time electrochemical data of the battery cell also includes: after determining that the battery cell is short-circuited, determining the severity level of the short circuit of the battery cell based on the voltage change rate.

[0011] In some embodiments, the severity level of the short circuit occurring in the battery cell is determined based on the voltage change rate, including: if the voltage change rate is greater than or equal to a second voltage change threshold, determining that a short circuit of a first severity level has occurred in the battery cell, wherein the second voltage change threshold is greater than the first voltage change threshold.

[0012] In some embodiments, the severity level of the short circuit occurring in the battery cell is determined based on the voltage change rate, including: if the voltage change rate is less than the second voltage change threshold, determining that a short circuit of a second severity level occurs in the battery cell, wherein the severity of the second severity level is lower than the severity of the first severity level.

[0013] In some embodiments, the voltage change rate is obtained by differentiating the voltage of the battery cell with respect to time and taking the negative value; the current change rate is obtained by differentiating the current of the battery cell with respect to time and taking the absolute value.

[0014] In some embodiments, the first voltage change threshold is the voltage change value corresponding to the battery cell capacity change of 0.1 times; the second voltage change threshold is the minimum voltage change value at the moment when the battery cell has an internal short circuit due to external force; the current change threshold is the current change value corresponding to the battery cell capacity change of 0.08 times.

[0015] In some embodiments, the change value of the real-time electrochemical data includes a first voltage difference and a second voltage difference; the first voltage difference is the voltage difference between a first voltage value and a second voltage value, wherein the voltage of the battery cell drops to the first voltage value and changes to the second voltage value, the second voltage value is greater than the first voltage value, and the second voltage value is less than the voltage value of the battery cell before the voltage drops; the second voltage difference is obtained by: obtaining the current value and change time of the battery cell during the period when the voltage of the battery cell changes from the first voltage value to the second voltage value, calculating the capacity change value corresponding to the change of the voltage of the battery cell from the first voltage value to the second voltage value according to the current value of the battery cell and the change time, and obtaining the second voltage difference according to the capacity change value and a preset capacity-voltage curve.

[0016] In some embodiments, the short circuit state of the battery cell is determined based on the change value of the real-time electrochemical data of the battery cell, including: if the first voltage difference is greater than a first voltage difference threshold and the second voltage difference is less than a second voltage difference threshold, it is determined that the battery cell is short-circuited.

[0017] In some embodiments, determining the short circuit state of the battery cell based on the change value of the real-time electrochemical data of the battery cell also includes: after determining that the battery cell is short-circuited, determining the severity level of the short circuit of the battery cell based on the first voltage difference.

[0018] In some embodiments, determining the severity level of the short circuit occurring in the battery cell based on the first voltage difference includes: if the first voltage difference is greater than or equal to a third voltage difference threshold, determining that a short circuit occurring in the battery cell occurs at a first severity level, wherein the third voltage difference threshold is greater than the first voltage difference threshold; if the first voltage difference is less than the third voltage difference threshold, determining that a short circuit occurring in the battery occurs at a second severity level, wherein the severity of the second severity level is lower than the severity of the first severity level.

[0019] In some embodiments, the battery unit includes a battery pack or a single battery, wherein the battery pack includes a plurality of single batteries connected in series and parallel.

[0020] A second aspect of the present invention provides a battery short circuit detection device, comprising: a processor; a memory connected to the processor in communication; wherein the memory stores a computer program executable by the processor, and when the processor executes the computer program, the battery short circuit detection method described in the above embodiment is implemented.

[0021] According to the battery short circuit detection device of the embodiment of the present invention, based on the characteristic of sudden change of real-time electrochemical data when a short circuit occurs in a battery cell, the short circuit state of the battery cell is detected by the change value, i.e., increase or decrease value, of the real-time electrochemical data generated by the battery cell during operation. For example, whether an internal short circuit occurs in the battery cell is detected by the change value, i.e., increase or decrease value, of the real-time electrochemical data of the battery cell. Therefore, compared with the prior art in which the electrochemical parameters of the short-circuited battery cell are changed by the accumulation of short-circuit leakage current and then the electrochemical parameters of the short-circuited battery cell are used to determine whether an internal short circuit occurs in the battery cell, in the present application, whether an internal short circuit occurs in the battery cell is detected by the change value of the real-time electrochemical data, and there is no need to trigger the internal short circuit fault detection of the battery cell after the restriction conditions are met after the short circuit fault occurs in the battery cell, thereby being able to detect the internal short circuit fault of the battery cell in time, thereby avoiding the problem of hysteresis in the identification of the internal short circuit fault of the battery cell.

[0022] In some embodiments, the system further includes: a sensor connected to the processor for detecting real-time electrochemical data of the battery cell.

[0023] A third aspect of the present invention provides a non-volatile computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed, implements the battery short circuit detection method of the above embodiment.

[0024] A fourth aspect of the present invention provides an electrical device, comprising a battery unit and the battery short circuit detection device described in the above embodiment, wherein the battery short circuit detection device is connected to the battery unit.

[0025] According to the electrical device of the embodiment of the present invention, the battery short circuit detection device of the above embodiment can identify the short circuit fault of the battery cell at the moment the battery cell is short-circuited, thereby avoiding the problem of hysteresis in the identification of the short circuit fault of the battery cell.

[0026] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 is a flow chart of a battery short circuit detection method according to an embodiment of the present invention; Figure 2 is a schematic diagram of a voltage mutation of a battery cell according to an embodiment of the present invention; Figure 3 is a schematic diagram of voltage mutation and temperature change of a battery cell according to an embodiment of the present invention; Figure 4 is a schematic diagram of voltage mutation and temperature change of a battery cell according to an embodiment of the present invention; Figure 5 is a flow chart of a battery short circuit detection method according to another embodiment of the present invention; Figure 6 is a structural block diagram of a battery short circuit detection device according to an embodiment of the present invention; Figure 7 is a structural block diagram of an electric device according to an embodiment of the present invention.

[0028] Reference numerals: Battery short circuit detection device 10; power consumption device 20; Processor 1; Memory 2; Battery unit 3. DETAILED DESCRIPTION

[0029] Embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Embodiments of the present invention are described in detail below.

[0030] At present, the battery can be a lithium-based rechargeable battery, wherein the lithium-based rechargeable battery includes lithium-ion batteries (LIBs) and lithium metal-based batteries (LMBs). The lithium-based rechargeable battery is a clean energy source and can alleviate the energy crisis and air pollution. Nowadays, lithium-ion batteries are becoming more and more important, and the requirements for the safety of lithium-ion batteries are also getting higher and higher. Therefore, it is crucial to reduce the occurrence of lithium-ion battery failures through new technologies such as internal material improvement and external system control. The self-induced internal short circuit generated on a micro scale within the battery structure is the main threat to the safety of battery use.

[0031] In order to solve the above problems, a first embodiment of the present invention provides a battery short circuit detection method, which can identify the short circuit fault of the battery cell at the moment the battery cell is short-circuited, thereby avoiding the problem of lag in identifying the short circuit fault of the battery cell.

[0032] Reference below Figure 1 A battery short circuit detection method according to an embodiment of the present invention is described. Figure 1 As shown, the method includes step S1.

[0033] Step S1, determining the short-circuit state of the battery cell according to the change value of the real-time electrochemical data of the battery cell.

[0034] Mechanical abuse can cause battery cells to short-circuit. Mechanical abuse is inevitable and can occur throughout the battery life cycle, causing irreversible damage to the battery, such as extrusion scratches during the production process and collision and extrusion during transportation; or foreign objects such as screws are left in the battery during battery installation; screws fail and fall into the battery during battery installation and use; or the vehicle rolls up foreign objects and brings them into the battery while driving, causing continuous extrusion and wear on the battery cells. The above-mentioned mechanical external forces cause the battery cells to short-circuit, increasing the risk of thermal runaway of the battery.

[0035] Specifically, in the related art, after a short circuit occurs in a battery cell, the electrochemical parameters of the short-circuited cell change due to the accumulation of short-circuit leakage current, and then the electrochemical parameters of the short-circuited cell are used to determine whether an internal short circuit occurs in the battery cell. However, the above short-circuit detection method can detect the internal short circuit of the battery cell only after the short circuit occurs in the battery cell and the restriction conditions are met, which leads to the problem of hysteresis in the identification of the internal short circuit of the battery cell. In order to solve the above problem, the short-circuit state of the battery cell is detected by the change value of the real-time electrochemical data generated by the battery cell in real time during operation, wherein the short-circuit state includes the internal short circuit, instead of waiting for the accumulation of short-circuit leakage current to cause the electrochemical parameters of the short-circuited cell to change after the short circuit occurs in the battery cell, and then judging whether the internal short circuit occurs in the battery cell by the electrochemical parameters of the short-circuited cell, so that the internal short circuit fault of the battery cell can be detected in time, thereby avoiding the problem of hysteresis in the identification of the internal short circuit fault of the battery cell, and having better practicality. The battery in the present application can be a lithium-based rechargeable battery, wherein the lithium-based rechargeable battery includes a lithium-ion battery and a lithium metal-based battery.

[0036] Exemplarily, when a short circuit occurs in a battery cell, real-time electrochemical data may mutate, for example, real-time voltage and real-time current may mutate. Based on this, the present application detects whether the battery cell is in a short-circuit state by the change value of the real-time electrochemical data generated by the battery cell in real time during operation, that is, to obtain the real-time electrochemical data of the battery cell, wherein the real-time electrochemical data may be understood as the electrochemical data generated by the battery cell in real time during operation, and the real-time electrochemical data includes at least real-time voltage and real-time current, etc., and then the short-circuit state of the battery cell is determined by the change value of the real-time electrochemical data, that is, the short-circuit state of the battery cell is determined by the increase or decrease value of the real-time electrochemical data. For example, during the operation of the battery cell, if the change value of the real-time electrochemical data of the battery cell satisfies the change condition when the battery cell is in a short-circuit state, then the battery cell is determined. The element is in a short-circuit state. For example, the real-time voltage and real-time current generated by the battery cell in real time during operation are used to detect whether the battery cell is in a short-circuit state. If the change value of the real-time voltage satisfies the change when the battery cell is in a short-circuit state, thus, in the present application, the short-circuit fault of the battery cell is detected by real-time electrochemical data, without the need to meet restriction conditions after the short-circuit fault of the battery cell occurs, such as meeting special charging and discharging conditions or static storage for a certain period of time to trigger the battery cell fault detection. Instead, the internal short-circuit fault of the battery cell can be identified at the moment of the battery cell short circuit, thereby avoiding the problem of lag in the identification of the internal short-circuit fault of the battery cell, and at the same time avoiding the potential risks caused by untimely identification of the internal short circuit. Moreover, the battery short-circuit detection method of the present application can be used throughout the life cycle of the electronic device without the need for special use conditions, and has better practicality.

[0037] According to the battery short circuit detection method of the embodiment of the present invention, based on the characteristic of sudden change of real-time electrochemical data when a short circuit occurs in a battery cell, the short circuit state of the battery cell is detected by the change value, i.e., increase or decrease value, of the real-time electrochemical data generated by the battery cell during operation. For example, whether an internal short circuit occurs in the battery cell is detected by the change value, i.e., increase or decrease value, of the real-time electrochemical data of the battery cell. Therefore, compared with the prior art in which the electrochemical parameters of the short-circuited cell are changed by the accumulation of short-circuit leakage current and then the electrochemical parameters of the short-circuited cell are used to determine whether an internal short circuit occurs in the battery cell, in the present application, whether an internal short circuit occurs in the battery cell is detected by the change value of the real-time electrochemical data, and there is no need to trigger the internal short circuit fault detection of the battery cell after the restriction conditions are met after the short circuit fault occurs in the battery cell, thereby being able to detect the internal short circuit fault of the battery cell in time, thereby avoiding the problem of hysteresis in the identification of the internal short circuit fault of the battery cell.

[0038] In some embodiments, the change value of the real-time electrochemical data includes the voltage change rate and the current change rate; the short-circuit state of the battery cell is determined based on the change value of the real-time electrochemical data, including: if the voltage change rate is greater than a first voltage change threshold and the current change rate is less than a current change threshold, it is determined that a short circuit has occurred in the battery cell.

[0039] Specifically, Figure 2-Figure 4 As shown, when a short circuit occurs in a battery cell, the voltage and current of the battery cell will suddenly change, that is, the voltage change rate and the current change rate will increase, and the current change rate is smaller. Therefore, whether a short circuit occurs in the battery cell is determined based on the voltage change rate and the current change rate. That is to say, in the present application, a critical value of the current change rate when the battery is short-circuited, that is, a first voltage change threshold value, is set. By comparing the voltage change rate with the first voltage change threshold value, if the voltage change rate is greater than the first voltage change threshold value, the voltage of the battery cell suddenly changes at this time. When the voltage change rate is greater than the first voltage change threshold value, since the voltage suddenly changes, the voltage suddenly changes, the minimum current change rate when the current suddenly changes and causes the voltage suddenly changes, that is, the current change threshold value, is set. Then the current change rate is compared with the current change threshold value. If the current change rate is less than the current change threshold value, the voltage suddenly changes. Threshold, it means that the voltage mutation of the battery cell is not caused by the current mutation, but the voltage mutation caused by the short circuit of the battery cell. Therefore, if the voltage change rate is greater than the first voltage change threshold and the current change rate is less than the current change threshold, it is determined that the battery cell is short-circuited. On the contrary, if the voltage change rate is less than the first voltage change threshold, it is determined that the battery cell is not short-circuited. If the current change rate is greater than the current change threshold, it is determined that the voltage mutation caused by the current mutation is determined. Therefore, in this application, a composite judgment is made by the voltage change rate and the current change rate to determine whether the battery cell is short-circuited, so that the short circuit fault of the battery cell can be identified at the moment of the short circuit of the battery cell, thereby avoiding the problem of hysteresis in the identification of the short circuit fault of the battery cell, and avoiding the potential risks caused by the untimely identification of the short circuit. In addition, the current change threshold can be the discharge rate selected by the first voltage change threshold minus 0.02C.

[0040] It should be noted that when recording the voltage and current signals of the battery cell, the acquisition frequency has a certain impact on the acquisition results. If the sampling interval is long, such as recording the voltage and current signals once every 10 seconds, the sudden voltage signal at the moment of short circuit may be missed. At this time, the voltage change rate and current change rate obtained are small; if the sampling interval is short, such as recording the voltage and current signals once every 0.1 seconds, the effective recording of the sudden voltage signal can be achieved. It can be seen that a shorter sampling interval needs to be set to effectively ensure the detection of the sudden voltage signal.

[0041] In some embodiments, determining the short circuit state of the battery cell according to the change value of the real-time electrochemical data of the battery cell further includes: after determining that the battery cell is short-circuited, determining the severity level of the short circuit of the battery cell according to the voltage change rate.

[0042] Specifically, after determining that a short circuit occurs in a battery cell, the severity of the short circuit in the battery cell is determined based on the voltage change rate because the degree of voltage mutation caused by different degrees of short circuit in the battery cell is different. For example, the preset voltage change rate range corresponding to different levels of short circuit is divided according to the size of the voltage change rate. Thus, the severity of the short circuit in the battery cell can be determined based on the voltage change rate. In this application, while identifying the short circuit in the battery cell, the severity of the short circuit in the battery cell can also be identified. In addition, the smaller the short-circuit resistance in the battery cell, the more obvious the voltage mutation of the battery cell at the moment of the short circuit, that is, the voltage change rate.

[0043] In some embodiments, the severity level of the short circuit in the battery cell is determined based on the voltage change rate, that is, if the voltage change rate is greater than or equal to a second voltage change threshold, wherein the second voltage change threshold is a voltage change threshold preset according to the severity of the short circuit in the battery cell, and the second voltage change threshold is greater than the first voltage change threshold, then it is determined that a short circuit of the first severity level has occurred in the battery cell, and the short circuit in the battery cell occurs in the middle of the short circuit; if the voltage change rate is less than the second voltage change threshold, if the voltage change rate is less than the second voltage change threshold, then it is determined that a short circuit of the second severity level has occurred in the battery cell, and the short circuit in the battery cell occurs in the early stage of the short circuit, and the severity of the second severity level is lower than the severity of the first severity level.

[0044] In addition, if Figure 3 As shown, in the present application, the time when the battery cell is short-circuited will not cause the temperature of the battery cell to change at the initial stage of the short circuit, such as Figure 4 As shown, in the present application, when a short circuit occurs in a battery cell, the temperature of the battery cell changes significantly in the middle of the short circuit.

[0045] In some embodiments, the voltage change rate is obtained by differentiating the voltage of the battery cell with respect to time and taking the negative value, for example, the voltage change rate is expressed as -dV / dt, where the voltage change rate is a negative value; since a sudden drop in charging current or a sudden increase in discharging current will cause a sudden drop in voltage, the current change rate dI / dt is obtained by differentiating the current of the battery cell with respect to time and taking the absolute value, that is, the absolute value of dI / dt is used as the current change rate. In this way, the voltage change rate and the current change rate are obtained, so as to facilitate a composite judgment through the voltage change rate and the current change rate to determine whether a short circuit occurs in the battery cell.

[0046] In some embodiments, the first voltage change threshold is the voltage change value corresponding to a battery cell capacity change of 0.1 times; the second voltage change threshold is the minimum voltage change value at the moment when the battery cell is short-circuited due to external force, for example, the battery cell packaging shell may be an aluminum plastic film, and the packaging shell may be damaged due to mechanical pressure, resulting in an internal short circuit; the current change threshold is the current change value corresponding to a battery cell capacity change of 0.08 times. In addition, in actual applications, the first voltage change threshold, the second voltage change threshold, and the current change threshold can be adjusted according to the use conditions.

[0047] In some embodiments, the change value of the real-time electrochemical data includes a first voltage difference and a second voltage difference; the first voltage difference is the voltage difference between the first voltage value and the second voltage value, wherein the voltage of the battery cell drops to the first voltage value and changes to the second voltage value, the second voltage value is greater than the first voltage value, and the second voltage value is less than the voltage value of the battery cell before the voltage drops.

[0048] Wherein, the second voltage difference is obtained by: obtaining the current value and change time of the battery cell during the period when the voltage of the battery cell changes from the first voltage value to the second voltage value, and calculating the capacity change value corresponding to the change of the voltage of the battery cell from the first voltage value to the second voltage value according to the current value and change time of the battery cell, that is, calculating the first capacity value corresponding to the first voltage value by the current value and change time of the battery cell, and calculating the second capacity value corresponding to the second voltage value by the current value and change time of the battery cell, thereby obtaining the capacity change value corresponding to the change of the voltage of the battery cell from the first voltage value to the second voltage value, wherein the capacity change value is the difference between the first capacity value and the first capacity value, and then obtaining the second voltage difference according to the capacity change value and the preset capacity-voltage curve, wherein the capacity change value and the second voltage difference in the capacity-voltage curve are in a one-to-one correspondence, thereby obtaining the corresponding second voltage difference according to the capacity change value.

[0049] In some embodiments, determining the short circuit state of the battery cell according to the change value of the real-time electrochemical data includes: if the first voltage difference is greater than the first voltage difference threshold and the second voltage difference is less than the second voltage difference threshold, determining that the battery cell is short-circuited.

[0050] Specifically, when a short circuit occurs in a battery cell, the voltage of the battery cell may rebound after a sudden change, so that the voltage change rate is less than the first voltage change threshold, thereby misjudging the short circuit fault of the battery cell. In order to solve this problem, in the present application, when determining that the voltage of the battery cell drops to a first voltage value and recovers to a second voltage value, the first voltage difference is compared with the first voltage difference threshold. If the first voltage difference is greater than the first voltage difference threshold, the voltage of the battery cell suddenly changes. When the first voltage difference is greater than the first voltage difference threshold, the voltage suddenly changes because the current suddenly changes, and the second voltage difference threshold is based on the current of the battery cell. The calculation is based on the result, so the lowest second voltage difference threshold value when the current mutation causes the voltage mutation can be set, and then the second voltage difference is compared with the second voltage difference threshold value. If the second voltage difference is less than the second voltage difference threshold value, it means that the voltage mutation of the battery cell is not caused by the current mutation, but is caused by a short circuit in the battery cell. In this case, it is determined that a short circuit has occurred in the battery cell. Therefore, if the first voltage difference is greater than the first voltage difference threshold value and the second voltage difference is less than the second voltage difference threshold value, it is determined that a short circuit has occurred in the battery cell. Therefore, in the present application, the short circuit fault detection when the voltage of the battery cell rebounds after a sudden drop is determined by the first voltage difference and the second voltage difference.

[0051] On the contrary, if the first voltage difference is less than the first voltage difference threshold, it is determined that the battery cell is not short-circuited, and if the second voltage difference is greater than the second voltage difference threshold, it is determined that the voltage mutation is caused by the current mutation.

[0052] In some embodiments, determining the short circuit state of the battery cell according to the change value of the real-time electrochemical data further includes: after determining that the battery cell is short-circuited, determining the severity level of the short circuit of the battery cell according to the first voltage difference.

[0053] Specifically, after determining that a short circuit has occurred in a battery cell, the severity of the short circuit in the battery cell is determined based on the first voltage difference because the degree of voltage mutation caused by different degrees of short circuit in the battery cell is different. For example, a preset first voltage difference range corresponding to different levels of short circuit is divided according to the size of the first voltage difference. Thus, the severity of the short circuit in the battery cell can be judged based on the first voltage difference. In the present application, while identifying that a short circuit has occurred in the battery cell, the severity of the short circuit in the battery cell can also be identified.

[0054] In some embodiments, determining the severity level of a short circuit in a battery cell based on a first voltage difference includes: if the first voltage difference is greater than or equal to a third voltage difference threshold, determining that a short circuit of a first severity level has occurred in the battery cell, wherein the third voltage difference threshold is greater than the first voltage difference threshold; if the first voltage difference is less than the third voltage difference threshold, determining that a short circuit of a second severity level has occurred in the battery, wherein the severity of the second severity level is lower than the severity of the first severity level.

[0055] Specifically, if the first voltage difference is greater than or equal to the third voltage difference threshold, wherein the third voltage difference threshold is a voltage difference threshold preset according to the severity of the short circuit of the battery cell, if the third voltage difference threshold is greater than the first voltage difference threshold, it is determined that the battery cell has a short circuit of the first severity level, and the short circuit of the battery cell occurs in the middle of the short circuit; if the first voltage difference is less than the third voltage difference threshold, it is determined that the battery cell has a short circuit of the second severity level, and the short circuit of the battery cell occurs in the early stage of the short circuit, wherein the severity of the second severity level is lower than the severity of the first severity level. Therefore, in the present application, while identifying the occurrence of a short circuit in the battery cell, the severity of the short circuit in the battery cell can also be identified.

[0056] In some embodiments, the battery unit includes a battery pack or a single cell, wherein the battery pack includes a plurality of single cells connected in series and parallel. For a battery pack, the method of the embodiment of the present invention identifies a short circuit of the battery pack, for example, including an internal short circuit of a single cell or a short circuit state between single cells. For a single cell, the internal short circuit of a single cell can be identified by the method of the embodiment of the present invention, wherein the internal short circuit of a single cell refers to a short circuit inside the single cell, that is, the conductive charge between the positive and negative electrodes inside the single cell is conducted, and the external short circuit of a single cell is a direct connection between the positive and negative electrodes outside the single cell.

[0057] Exemplarily, the single cell is a lithium-ion battery, the positive electrode active material is lithium cobalt oxide, the negative electrode active material is graphite, the diaphragm is a double-sided ceramic diaphragm, the rated capacity is 5Ah, and the real-time electrochemical data acquisition frequency is 0.1s. In this application, the short-circuit state of the first single cell, the second single cell and the third single cell is detected, wherein, when the single cell undergoes a 0.1C rate mutation, the voltage change of the single cell is as follows: Figure 2 As shown, the first voltage change threshold for determining the voltage change rate of a battery cell short circuit is set to 30mV / s. The current change threshold for determining whether the battery voltage fault is caused by a current mutation is set to 0.08C, and the second voltage change threshold for determining the first severity level of a single cell obtained by experiment is set to 1000mV / s.

[0058] In this embodiment, a short-circuit test is performed on the second single cell and the third single cell in a static state. When the voltage change rate of the second single cell is greater than the first voltage change threshold value, and the current change rate is 0 and less than the current change threshold value, it is determined that the second single cell has a short circuit, and when the voltage change rate is less than the second voltage change threshold value, it is determined that the short circuit of the second single cell is in the early stage of the short circuit; when the voltage change rate of the third single cell is greater than the first voltage change threshold value, and the current change rate is 0 and less than the current change threshold value, it is determined that the short circuit of the third single cell occurs, and when the voltage change rate of the third single cell is greater than the second voltage change threshold value, it is determined that the short circuit of the third single cell occurs. In addition, when the voltage change rate of the third single cell is greater than the second voltage change threshold value, it is determined that the short circuit of the third single cell is in the middle stage of the short circuit.

[0059] Reference below Figure 5 The battery short circuit detection method according to the embodiment of the present invention is illustrated by way of example, and the specific contents are as follows.

[0060] Step S3, collecting real-time electrochemical data of the battery cell, namely, voltage and current, during use of the battery cell, wherein the battery cell may be a lithium-ion battery.

[0061] Step S4, performing differentiation processing on the real-time electrochemical data to obtain the voltage change rate and the current change rate.

[0062] Step S5, determining whether the voltage change rate is greater than a first voltage change threshold, if so, executing step S7, otherwise executing step S6.

[0063] Step S6: determine that the battery cell is not short-circuited.

[0064] Step S7, determining whether the current change rate is less than the current change threshold, if so, executing step S9, otherwise executing step S8.

[0065] In step S8, the voltage mutation caused by the current mutation is determined.

[0066] Step S9, determining whether the voltage change rate is greater than or equal to a second voltage change threshold, if so, executing step S11, otherwise executing step S10.

[0067] In step S10, it is determined that a short circuit of the second severity level occurs in the battery cell, that is, an internal short circuit occurs in the battery cell, but the battery cell temperature is substantially not changed.

[0068] In step S11 , it is determined that a short circuit of the first severity level occurs in the battery cell, that is, an internal short circuit occurs in the battery cell and causes a significant temperature change in the battery cell.

[0069] It should be noted that the above short circuit detection method can detect short circuits in single cells, and can also determine whether there are single cells in the battery pack with internal short circuits. However, for the current and voltage between single cells in the battery pack, when it is detected in step S5 that the voltage change rate is greater than the first voltage change threshold, it is considered that the voltage mutation of the battery cell at this time is caused by the current mutation.

[0070] A second aspect of the present invention provides a battery short circuit detection device 10, such as Figure 6 As shown, the device 10 includes: a processor 1 and a memory 2.

[0071] Among them, there is a processor and a memory connected to the processor in communication; the memory stores a computer program that can be executed by the processor, and when the processor executes the computer program, the battery short circuit detection method of the above embodiment is implemented.

[0072] In an embodiment, the battery short circuit detection device 10 may be a hardware device that actually applies the above battery short circuit detection method. The hardware device may include but is not limited to a distribution box, a detection circuit for detecting a short circuit of a battery cell, a chip, etc.

[0073] In some embodiments, the battery short circuit detection device also includes: a sensor, the sensor is connected to the processor, the sensor is used to detect real-time electrochemical data of the battery cell, and send the real-time electrochemical data of the detected battery cell to the processor, so that the processor can detect the short circuit state of the battery cell through the real-time electrochemical data.

[0074] According to the battery short circuit detection device of the embodiment of the present invention, based on the characteristic of sudden change of real-time electrochemical data when a short circuit occurs in a battery cell, the short circuit state of the battery cell is detected by the change value, i.e., increase or decrease value, of the real-time electrochemical data generated by the battery cell during operation. For example, whether an internal short circuit occurs in the battery cell is detected by the change value, i.e., increase or decrease value, of the real-time electrochemical data of the battery cell. Therefore, compared with the prior art in which the electrochemical parameters of the short-circuited battery cell are changed by the accumulation of short-circuit leakage current and then the electrochemical parameters of the short-circuited battery cell are used to determine whether an internal short circuit occurs in the battery cell, in the present application, whether an internal short circuit occurs in the battery cell is detected by the change value of the real-time electrochemical data, and there is no need to trigger the internal short circuit fault detection of the battery cell after the restriction conditions are met after the short circuit fault occurs in the battery cell, thereby being able to detect the internal short circuit fault of the battery cell in time, thereby avoiding the problem of hysteresis in the identification of the internal short circuit fault of the battery cell.

[0075] A third aspect of the present invention provides a non-volatile computer-readable storage medium having a computer program stored thereon, which implements the battery short circuit detection method of the above embodiment when the computer program is processed.

[0076] In an embodiment, "computer readable medium" may be any device that can contain, store, communicate, propagate or transport a program for use in an instruction execution system, apparatus or device or in conjunction with such instruction execution system, apparatus or device. For example, a computer readable storage medium may be a read-only memory, a magnetic disk or an optical disk, etc. More specific examples (a non-exhaustive list) include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM).

[0077] A fourth aspect of the present invention provides an electrical device 20, such as Figure 7 As shown, the electrical device 20 includes a battery cell 3 and the battery short circuit detection device 10 of the above embodiment, the battery short circuit detection device 10 is connected to the battery cell 3, the electrical device may include a vehicle or an electronic device or other device that needs to consume electrical energy, the electrical device may be a tablet computer, a mobile phone, a computer, etc., and there is no limitation on this.

[0078] It should be noted that the specific implementation of the electrical device in the embodiment of the present invention is similar to the specific implementation of the battery short circuit detection method in any of the above embodiments of the present invention. Please refer to the description of the method part for details. In order to reduce redundancy, it will not be repeated here.

[0079] According to the electrical device of the embodiment of the present invention, the battery short circuit detection device of the above embodiment can identify the short circuit fault of the battery cell at the moment the battery cell is short-circuited, thereby avoiding the problem of hysteresis in the identification of the short circuit fault of the battery cell.

[0080] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0081] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery short circuit detection method, characterized in that: include: The short circuit state of the battery cell is determined according to the change value of the real-time electrochemical data of the battery cell.

2. The battery short circuit detection method according to claim 1, characterized in that: The change value of the real-time electrochemical data includes a voltage change rate and a current change rate; Determining the short-circuit state of the battery cell according to a change value of real-time electrochemical data of the battery cell includes: If the voltage change rate is greater than a first voltage change threshold and the current change rate is less than a current change threshold, it is determined that a short circuit occurs in the battery cell.

3. The battery short circuit detection method according to claim 2, characterized in that: Determining the short circuit state of the battery cell according to the change value of the real-time electrochemical data of the battery cell also includes: After determining that the battery cell is short-circuited, a severity level of the short-circuit of the battery cell is determined according to the voltage change rate.

4. The battery short circuit detection method according to claim 3, characterized in that: Determining the severity level of the short circuit of the battery cell according to the voltage change rate includes: If the voltage change rate is greater than or equal to a second voltage change threshold, it is determined that a short circuit of a first severity level occurs in the battery cell, wherein the second voltage change threshold is greater than the first voltage change threshold.

5. The battery short circuit detection method according to claim 4, characterized in that: Determining the severity level of the short circuit of the battery cell according to the voltage change rate includes: If the voltage change rate is less than the second voltage change threshold, it is determined that a short circuit of a second severity level occurs in the battery cell, wherein the severity of the second severity level is lower than the severity of the first severity level.

6. The battery short circuit detection method according to any one of claims 2 to 5, characterized in that: The voltage change rate is obtained by differentiating the voltage of the battery cell with respect to time and taking the negative value; The current change rate is obtained by differentiating the current of the battery cell with respect to time and taking the absolute value.

7. The battery short circuit detection method according to claim 4 or 5, characterized in that: The first voltage change threshold is a voltage change value corresponding to a 0.1-fold change in the battery cell capacity of the battery cell; The second voltage change threshold is the minimum voltage change value at the moment when the battery cell is internally short-circuited due to external force; The current change threshold is a current change value corresponding to a change in the battery cell capacity of 0.08 times.

8. The battery short circuit detection method according to claim 1, characterized in that: The change value of the real-time electrochemical data includes a first voltage difference and a second voltage difference; The first voltage difference is a voltage difference between a first voltage value and a second voltage value, wherein the voltage of the battery cell drops to the first voltage value and changes to the second voltage value, the second voltage value is greater than the first voltage value, and the second voltage value is less than the voltage value of the battery cell before the voltage drops; The second voltage difference is obtained by: obtaining the current value and change time of the battery cell during the period when the voltage of the battery cell changes from the first voltage value to the second voltage value, calculating the capacity change value corresponding to the change of the voltage of the battery cell from the first voltage value to the second voltage value according to the current value of the battery cell and the change time, and obtaining the second voltage difference according to the capacity change value and a preset capacity-voltage curve.

9. The battery short circuit detection method according to claim 8, characterized in that: Determining the short-circuit state of the battery cell according to a change value of real-time electrochemical data of the battery cell includes: If the first voltage difference is greater than a first voltage difference threshold and the second voltage difference is less than a second voltage difference threshold, it is determined that a short circuit occurs in the battery cell.

10. The battery short circuit detection method according to claim 9, characterized in that: Determining the short circuit state of the battery cell according to the change value of the real-time electrochemical data of the battery cell also includes: After determining that the battery cell is short-circuited, a severity level of the short-circuit of the battery cell is determined according to the first voltage difference.

11. The battery short circuit detection method according to claim 10, characterized in that: Determining the severity level of the short circuit of the battery cell according to the first voltage difference includes: If the first voltage difference is greater than or equal to a third voltage difference threshold, it is determined that a short circuit of a first severity level occurs in the battery cell, wherein the third voltage difference threshold is greater than the first voltage difference threshold; If the first voltage difference is less than the third voltage difference threshold, it is determined that a short circuit of a second severity level occurs in the battery, wherein the severity of the second severity level is lower than the severity of the first severity level.

12. The battery short circuit detection method according to any one of claims 1 to 5 or 8 to 11, characterized in that: The battery unit includes a battery pack or a single battery, wherein the battery pack includes a plurality of single batteries connected in series and parallel.

13. A battery short circuit detection device, characterized in that: include: processor; a memory communicatively coupled to the processor; The memory stores a computer program executable by the processor, and the processor implements the battery short circuit detection method according to any one of claims 1 to 12 when executing the computer program.

14. The battery short circuit detection device according to claim 13, characterized in that: Also includes: The sensor is connected to the processor and is used to detect real-time electrochemical data of the battery cell.

15. A non-volatile computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the battery short circuit detection method according to any one of claims 1 to 12 is implemented.

16. An electrical device, characterized in that: It comprises a battery cell and the battery short circuit detection device according to claim 13 or 14, wherein the battery short circuit detection device is connected to the battery cell.

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