Fault detection method, battery management system and battery pack

Abstract

The present application discloses a fault detection method, a battery management system and a battery pack, the fault detection method comprising: obtaining at least two air pressure data of the battery pack at different acquisition times within a preset acquisition time, the air pressure statistical result is used to reflect the air pressure change of the battery pack within the preset acquisition time; according to at least two air pressure data, determining the air pressure statistical result within the preset acquisition time, the air pressure statistical result includes the air pressure variance result within the preset acquisition time; in response to the air pressure variance result within the preset acquisition time satisfying the first condition, determining that the battery pack has an arcing fault. In this way, the arcing fault is identified according to the statistical results of the air pressure data, which can not only accurately identify the occurrence of the arcing fault, but also can timely disconnect the protection device placed in the arcing circuit after identifying the arcing fault of the battery pack, thereby improving the safety and reliability of the battery pack.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a fault detection method, a battery management system and a battery pack. Background Art

[0002] With the rapid development of renewable energy, battery packs, as a type of energy that can be repeatedly charged and discharged, have broad application prospects in the energy field. During the use of the battery pack, the battery insulation in the battery pack may fail due to impurities or particles in the battery material, or the battery pack is squeezed. When the battery insulation fails, the potential difference between the two batteries is large, which will cause a high-voltage arc fault. If the arc fault is not identified after the battery pack has an arc fault, it will cause serious damage to the battery pack and is not conducive to the safety of the battery pack. Summary of the invention

[0003] The present application proposes a fault detection method, a battery management system, and a battery pack, which can accurately identify the occurrence of an arcing fault after an arcing fault occurs in the battery pack, thereby improving the safety and reliability of the battery pack.

[0004] The technical solution of this application is implemented as follows:

[0005] In a first aspect, an embodiment of the present application provides a fault detection method, the fault detection method comprising:

[0006] Obtain at least two air pressure data of the battery pack at different collection times within a preset collection time;

[0007] Determine the air pressure statistics within a preset collection time according to at least two air pressure data, the air pressure statistics are used to reflect the air pressure change of the battery pack within the preset collection time, and the air pressure statistics include the air pressure variance result within the preset collection time;

[0008] In response to the air pressure variance result within the preset collection time satisfying the first condition, it is determined that an arc fault occurs in the battery pack.

[0009] Through the above-mentioned technical means, at least two air pressure data of the battery pack at different collection times within the preset collection time are obtained, and the air pressure statistical result within the preset collection time is determined based on the at least two air pressure data. The air pressure statistical result is used to reflect the air pressure change of the battery pack within the preset collection time. Then, it is determined whether the battery pack has an arcing fault based on the air pressure statistical result. Specifically, when the air pressure statistical result includes the air pressure variance result within the preset collection time, in response to the air pressure variance result within the preset collection time satisfying the first condition, it is determined that the battery pack has an arcing fault. In this way, since the arc discharge caused by the arcing fault in the battery pack will generate a large amount of heat and gas, causing the air pressure data of the battery pack to change dramatically, the arcing fault is identified based on the statistical results of the air pressure data in the battery pack at different collection times (such as air pressure rise, air pressure drop, or calculated variance of air pressure, etc.). Specifically, considering that the arcing fault in the battery pack will cause the air pressure inside the battery pack to change dramatically (for example, the air pressure rises sharply and then drops sharply), the arcing fault is identified based on the air pressure variance result within the preset collection time. The air pressure variance result can measure the degree of deviation between a set of air pressure data and its mathematical expectation (i.e., the air pressure mean). At this time, the occurrence of the arcing fault can be accurately identified, thereby improving the accuracy of arcing fault identification; and after identifying the arcing fault in the battery pack, the protection device placed in the arcing circuit can be disconnected in time to avoid further expansion and deterioration of the arcing fault of the battery pack, thereby improving the safety and reliability of the battery pack.

[0010] In some embodiments, the air pressure statistical results also include the air pressure change rate within a preset collection time; the fault detection method also includes: when the air pressure variance result within the preset collection time does not meet the first condition, in response to the air pressure change rate within the preset collection time meeting the second condition, determining that the battery pack has an arc fault.

[0011] Through the above technical means, if the air pressure variance result within the preset acquisition time does not meet the first condition, further judgment is made through the air pressure change rate within the preset acquisition time. For example, if the air pressure change rate within the preset time meets the second condition, it is determined that the battery pack has an arcing fault. In this way, if the air pressure variance result within the preset acquisition time does not meet the first condition, it is determined that the battery pack does not have an arcing fault. At this time, the arcing fault judgment is further performed based on the air pressure change rate within the preset acquisition time. In this way, the use of double judgment can not only accurately identify the occurrence of arcing faults, thereby improving the accuracy of arcing fault identification; and after identifying that the battery pack has an arcing fault, the protective device placed in the arcing circuit can be disconnected in time to avoid further expansion and deterioration of the arcing fault of the battery pack, thereby improving the safety and reliability of the battery pack.

[0012] In some embodiments, the air pressure change rate includes a first change rate for characterizing an increase in air pressure data; in response to the air pressure change rate within a preset acquisition time satisfying a second condition, determining that an arcing fault has occurred in the battery pack includes: in response to the first change rate being greater than or equal to a preset air pressure rise threshold and lasting for a first preset time, determining that an arcing fault has occurred in the battery pack.

[0013] Through the above-mentioned technical means, when the first change rate of the rise of the air pressure data characterizing the preset collection time is greater than or equal to the preset air pressure rise threshold and lasts for the first preset time, it is determined that an arc fault has occurred in the battery pack. Taking into account that an arc fault in the battery pack will cause the air pressure inside the battery pack to rise sharply, arc fault identification is performed based on the first change rate of the rise in air pressure data, and the occurrence of arc fault can be accurately identified, thereby improving the accuracy of arc fault identification.

[0014] In some embodiments, the air pressure change rate includes a second change rate for characterizing a drop in air pressure data; in response to the air pressure change rate within a preset acquisition time satisfying a second condition, determining that an arcing fault has occurred in the battery pack includes: in response to the second change rate being less than or equal to a preset air pressure drop threshold and lasting for a second preset time, determining that an arcing fault has occurred in the battery pack.

[0015] Through the above technical means, when the second change rate of the air pressure data drop within the preset collection time is less than or equal to the preset air pressure drop threshold and lasts for the second preset time, it is determined that the battery pack has an arc fault. Considering that the arc fault in the battery pack will cause the air pressure inside the battery pack to rise sharply and then drop sharply, the arc fault is identified based on the second change rate of the air pressure data drop, which can also accurately identify the occurrence of the arc fault and improve the accuracy of arc fault identification.

[0016] In some embodiments, the air pressure change rate includes a first change rate for characterizing an increase in air pressure data and a second change rate for characterizing a decrease in air pressure data; in response to the air pressure change rate within a preset acquisition time satisfying a second condition, determining that an arcing fault has occurred in the battery pack includes: in response to the first change rate being greater than or equal to a preset air pressure rise threshold and lasting for a first preset time and the second change rate being less than or equal to a preset air pressure drop threshold and lasting for a second preset time, determining that an arcing fault has occurred in the battery pack.

[0017] Through the above-mentioned technical means, after the first change rate characterizing the rise of the air pressure data within the preset collection time is greater than or equal to the preset air pressure rise threshold and continues for the first preset time, the second change rate characterizing the decrease of the air pressure data is less than or equal to the preset air pressure drop threshold and continues for the second preset time, it can be determined that the battery pack has an arcing fault. In this way, considering that the arcing fault in the battery pack will cause the air pressure inside the battery pack to rise sharply and then drop sharply, the arcing fault can also be identified by jointly using the first change rate characterizing the increase of the air pressure data and the second change rate characterizing the decrease of the air pressure data, and the occurrence of the arcing fault can also be accurately identified, thereby improving the accuracy of arcing fault identification.

[0018] In some embodiments, the air pressure statistical result also includes the air pressure change rate within a preset collection time; in response to the air pressure variance result within the preset collection time satisfying a first condition, determining that the battery pack has an arcing fault includes: judging whether the air pressure change rate within the preset collection time satisfies a second condition; if the air pressure change rate within the preset collection time does not satisfy the second condition, in response to the air pressure variance result within the preset collection time satisfying the first condition, determining that the battery pack has an arcing fault.

[0019] Through the above-mentioned technical means, if the air pressure variance result within the preset acquisition time does not meet the first condition, it is not determined whether the battery pack has an arcing fault. The arcing fault is further judged by the air pressure change rate within the preset acquisition time. If the air pressure change rate within the preset time meets the second condition, it is determined that the battery pack has an arcing fault. The use of double judgment can more accurately identify the occurrence of arcing faults, thereby improving the accuracy of arcing fault identification.

[0020] In some embodiments, the air pressure variance result within a preset acquisition time includes a calculated variance corresponding to the air pressure data for characterizing at least two acquisition moments; in response to the air pressure variance value within the preset acquisition time satisfying a first condition, determining that an arcing fault has occurred in the battery pack includes: in response to the calculated variance being greater than or equal to a preset variance threshold and lasting for a third preset time, determining that an arcing fault has occurred in the battery pack.

[0021] Through the above-mentioned technical means, since an arcing fault in the battery pack will cause a sharp change in the air pressure inside the battery pack (for example, the air pressure rises sharply and then drops sharply), the variance of the air pressure data at at least two collection moments is calculated, and when the calculated variance is greater than or equal to the preset variance threshold and lasts for a third preset time, it indicates that the air pressure data has fluctuated greatly. At this time, it can be determined that the battery pack has an arcing fault, thereby improving the accuracy of arcing fault identification.

[0022] In some embodiments, the fault detection method further includes: in response to an arc fault occurring in the battery pack, determining two target battery packs where the arc fault occurs in the battery pack; and sending a control signal to a protection device between the two target battery packs, the control signal being used to disconnect the protection device.

[0023] Through the above-mentioned technical means, after determining that the battery pack has an arc fault, the two target battery groups where the arc fault occurs in the battery are determined, that is, the arc circuit is determined, and the protection device placed in the arc circuit is disconnected to avoid further expansion and deterioration of the arc fault, thereby improving the safety and reliability of the battery pack.

[0024] In a second aspect, an embodiment of the present application provides a battery management system, the battery management system includes a collection unit and a processing unit, wherein:

[0025] A collection unit, configured to obtain at least two air pressure data of the battery pack at different collection times within a preset collection time;

[0026] The processing unit is configured to determine the air pressure statistics within a preset collection time based on at least two air pressure data, the air pressure statistics result is used to reflect the air pressure change of the battery pack within the preset collection time, the air pressure statistics result includes the air pressure variance result within the preset collection time; and in response to the air pressure variance result within the preset collection time satisfying the first condition, determine that the battery pack has an arc fault.

[0027] Through the above technical means, since the battery management system includes a collection unit and a processing unit, the arc discharge caused by the arcing fault in the battery pack will generate a large amount of heat and gas, causing the air pressure data of the battery pack to change dramatically. Therefore, the processing unit performs statistics on at least two air pressure data obtained by the collection unit, and performs arcing fault identification according to the air pressure statistical results (such as air pressure rise, air pressure drop, or calculated variance of air pressure, etc.). Specifically, considering that the arcing fault in the battery pack will cause the air pressure inside the battery pack to change dramatically (for example, the air pressure rises sharply and then drops sharply), the arcing fault is identified according to the air pressure variance result within the preset collection time. The air pressure variance result can measure the degree of deviation between a set of air pressure data and its mathematical expectation (i.e., the air pressure mean). At this time, the occurrence of the arcing fault can be accurately identified, thereby improving the accuracy of arcing fault identification; and after identifying the arcing fault in the battery pack, the protection device placed in the arcing circuit can be disconnected in time to avoid further expansion and deterioration of the arcing fault of the battery pack, thereby improving the safety and reliability of the battery pack.

[0028] In a third aspect, an embodiment of the present application provides a battery pack, the battery pack comprising at least two battery groups, at least one protection device, and a battery management system as described in the second aspect;

[0029] Among them, in at least two battery packs, a protection device is arranged between every two battery packs.

[0030] Through the above-mentioned technical means, the air pressure statistical data of the battery pack is obtained by statistically processing the air pressure data, and based on the air pressure statistical data, such as air pressure rise, air pressure drop or calculated variance of air pressure, it is possible to accurately determine whether the battery pack has an arcing fault, thereby improving the accuracy of arcing fault judgment; and after determining that the battery pack has an arcing fault, the arcing circuit is cut off by disconnecting the protection device to avoid further expansion and deterioration of the arcing fault, thereby ensuring the safety and reliability of the battery pack.

[0031] In some embodiments, the protection device includes at least one of the following: a relay, an instantaneous fuse, a smart fuse, and an electronic fuse.

[0032] Through the above-mentioned technical means, relays, instantaneous fuses, smart fuses and electronic fuses are used to disconnect the arc circuit after identifying the arc fault in the battery pack, avoiding further expansion and deterioration of the arc fault in the battery pack, thereby improving the safety and reliability of the battery pack.

[0033] In some embodiments, the battery pack further includes a collection sensor, wherein: the collection sensor is configured to collect air pressure data of the battery pack and send at least two air pressure data collected within a preset collection time to the battery management system.

[0034] Through the above technical means, the air pressure data of the battery pack is collected by the collection sensor, so that the battery management system can identify whether an arc fault occurs in the battery pack based on at least two air pressure data collected.

[0035] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and are not intended to limit the technical solutions of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of the structure of a battery pack provided in an embodiment of the present application Figure 1 ;

[0037] Figure 2 A schematic diagram of a fault detection method provided in an embodiment of the present application Figure 1 ;

[0038] Figure 3 A schematic diagram of a fault detection method provided in an embodiment of the present application Figure 2 ;

[0039] Figure 4 A schematic diagram of a fault detection method provided in an embodiment of the present application Figure 3 ;

[0040] Figure 5 A schematic diagram of a fault detection method provided in an embodiment of the present application Figure 4 ;

[0041] Figure 6 A schematic diagram of the structure of a battery management system provided in an embodiment of the present application;

[0042] Figure 7 A schematic diagram of the structure of a battery pack provided in an embodiment of the present application Figure 2 . DETAILED DESCRIPTION

[0043] In order to enable a more detailed understanding of the features and technical contents of the embodiments of the present application, the implementation of the embodiments of the present application is described in detail below in conjunction with the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present application.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0045] In the following description, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0046] It should also be pointed out that the terms "first\second\third" involved in the embodiments of the present application are only used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of the present application described here can be implemented in an order other than that illustrated or described here.

[0047] In addition, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0048] The following is an introduction to the related technologies of this application.

[0049] New energy batteries are being used more and more widely in life and industry. For example, new energy vehicles equipped with batteries have been widely used. In addition, batteries are also being increasingly used in areas such as energy storage.

[0050] At present, new energy batteries are increasingly used in life and industry. New energy batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0051] In the embodiment of the present application, the battery may be at least one battery cell, or may be a battery pack (Pack) composed of multiple battery cells. A battery cell refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and can be used to make a battery pack or a battery pack, so as to supply power to an electrical device. A battery cell may be a secondary battery, which refers to a battery cell that can be activated by charging the active material after the battery cell is discharged and can continue to be used. The battery cell may be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiment of the present application does not limit this. It should be noted that in the embodiment of the present application, a battery cell may be referred to as a battery cell.

[0052] In the embodiment of the present application, the battery may also be a single physical module including one or more battery cells to provide higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, in parallel or in hybrid connection through a busbar component.

[0053] Furthermore, during the use of the battery pack, due to impurities or particles in the battery material, or extrusion of the battery pack, the battery insulation in the battery pack may fail. If the insulation points of two or more batteries in the battery pack fail at the same time, this phenomenon can be called double-point insulation failure. When double-point insulation failure occurs, it means that a direct electrical connection has occurred between two electrical parts that should have been isolated, which may cause abnormal current flow, high temperature and arcing.

[0054] It should also be noted that the battery can be a cell or a battery pack, and "arcing" refers to an abnormal discharge phenomenon occurring inside or outside the battery pack, which is manifested as an arc generated when current passes through the air or other non-conductive media. This arc is usually caused by poor electrical connections, insulation damage, short circuits, accidental contact between metal parts, or other electrical faults. Arcing is extremely dangerous in a battery pack because it may cause a fire, explosion, or damage to battery components. The high temperature generated by the arc can quickly ignite flammable materials inside the battery pack, such as electrolyte or diaphragm, causing a fire. In addition, the arc may also cause physical damage to the electrical components of the battery system, further exacerbating the failure.

[0055] For example, when the insulation of a battery fails, it may be connected to the outside or other batteries through a conductor such as a box or steel belt. At this time, the two batteries are in a state of being connected but not connected. Then, an unstable electrical connection may be formed between the two batteries. In addition, there is a large potential difference between the two batteries, which will cause a high-voltage arc fault. In severe cases, the battery cell may break down and spread to catch fire, thereby causing serious consequences such as fire or explosion.

[0056] Simply put, during the use of the battery pack, the battery insulation in the battery pack may fail due to impurities or particles in the battery material, or the battery pack is squeezed, etc. When the battery insulation fails, the potential difference between the two batteries is large, which will cause a high-voltage arc fault, causing serious damage to the battery pack and is not conducive to the safety of the battery pack.

[0057] Based on this, an embodiment of the present application provides a fault detection method, which obtains at least two air pressure data of a battery pack within a preset acquisition time, and determines the air pressure statistical result within the preset acquisition time based on the at least two air pressure data, and then, when the air pressure statistical result includes the air pressure variance result within the preset acquisition time, in response to the air pressure variance result within the preset acquisition time satisfying the first condition, it is determined that an arc fault has occurred in the battery pack. In this way, since the arc discharge caused by the arcing fault in the battery pack will generate a large amount of heat and gas, causing the air pressure data of the battery pack to change dramatically, the arcing fault is identified based on the statistical results of the air pressure data of the battery pack (such as air pressure rise, air pressure drop, or calculated variance of air pressure, etc.). Specifically, considering that the arcing fault in the battery pack will cause the air pressure inside the battery pack to change dramatically (for example, the air pressure rises sharply and then drops sharply), the arcing fault is identified based on the air pressure variance result within the preset acquisition time. The air pressure variance result can measure the degree of deviation between a set of air pressure data and its mathematical expectation (i.e., the air pressure mean). At this time, the occurrence of the arcing fault can be accurately identified, thereby improving the accuracy of arcing fault identification; and after identifying the arcing fault in the battery pack, the protection device placed in the arcing circuit can be disconnected in time to avoid further expansion and deterioration of the arcing fault of the battery pack, thereby improving the safety and reliability of the battery pack.

[0058] The present application is further described in detail below through the accompanying drawings and specific embodiments.

[0059] In one embodiment of the present application, a battery pack may include at least two battery groups and at least one protection device, each battery group includes at least one battery cell; wherein a protection device is disposed between every two battery groups.

[0060] In an embodiment of the present application, at least two battery packs include a first battery pack, a second battery pack, ..., an Nth battery pack, wherein N is a positive integer, and the value of N is determined according to actual conditions, and no limitation is made thereto. In addition, for the battery cell, each battery cell has its specific operating voltage range, and exceeding this range may cause damage to the battery cell. In addition, the breakdown voltage of a single battery cell is the maximum voltage value it can withstand, and exceeding this value may cause the battery cell to be broken down. Therefore, when designing a battery pack, the number of battery cells in the battery pack must be reasonably determined based on the breakdown voltage of the battery cell to ensure that the battery pack operates within the normal operating range. Here, the battery cell may also be referred to as a battery monomer.

[0061] In the embodiments of the present application, a battery pack is generally composed of a plurality of battery cells connected in series or in parallel; a battery pack is composed of a plurality of battery packs (or directly of battery cells) connected in series or in parallel. Here, each battery pack is composed of at least one battery cell connected in series, and the battery packs are connected in series through a protective device.

[0062] In an embodiment of the present application, in order to ensure electrical isolation between battery packs, insulating materials or insulating layers need to be provided between the battery packs. These insulating materials or insulating layers can effectively prevent current from flowing between battery packs. In addition, insulation treatment is also required between the battery cells inside the battery pack. This is usually achieved by inserting an insulating sheet between the battery cells or using an insulating frame to prevent the failure of a single battery cell from spreading to other battery cells. In other words, in order to ensure the safe operation of the battery pack, both the battery cells and the battery pack need to be insulated and isolated accordingly to prevent current from flowing on paths that should not flow, thereby avoiding safety issues.

[0063] In addition, for a battery pack, if the types of cells it includes can be the same, in order to ensure the safety of the battery pack, the number of cells p in the battery pack needs to be less than the breakdown voltage q of the battery pack divided by the cell voltage f, that is, p

[0064] For example, if the breakdown voltage of a single battery cell is about 80 volts (V) and the battery cell voltage is about 4V, then the battery pack may include 20 battery cells connected in series.

[0065] In the embodiment of the present application, if the double-point insulation failure occurs in the same battery pack, since the working voltage flowing in the battery pack will be lower than the breakdown voltage of the battery pack, the working voltage does not reach the breakdown voltage of the battery pack at this time, and arcing breakdown will not occur. If the double-point insulation failure occurs in different battery packs, since the two battery packs are connected in series, the voltage of the series circuit will increase, making the working voltage much higher than the breakdown voltage of the battery pack, causing a high-voltage arc (i.e., an arcing failure) to occur between the two battery packs.

[0066] ​In the embodiment of the present application, the high temperature generated by the high-voltage arc will cause the electrolyte, electrode materials, etc. inside the battery pack to be rapidly vaporized, forming a large amount of gas. These gases will expand rapidly under the high temperature of the arc. When the arc breaks through the outer shell or safety valve of the battery pack, the high-temperature gas and arc energy will be instantly released to the outside of the battery pack. This sudden release will form a pressure wave, causing the air pressure in the battery pack to fluctuate violently. At this time, it is possible to determine whether the battery pack has an arc fault by identifying the air pressure characteristic signal (also known as air pressure data). If an arc fault occurs in the battery pack, it is necessary to determine the two battery packs in the battery pack where the arc fault occurs, and disconnect the protection device between the two battery packs to avoid continuous breakdown and cause the battery pack to spread and catch fire. It should be noted that arc breakdown refers to the phenomenon that when the voltage is too high or the current is too large in the circuit, the medium that should not be conductive (such as air, insulating material, etc.) is broken down, forming an arc and causing the current to continue to flow.

[0067] It should be noted that in the present application and the following embodiments, the determination of whether an arc fault occurs in a battery pack is based on the occurrence of double-point insulation failure between different battery packs.

[0068] In one possible embodiment, Figure 1 A schematic diagram of the structure of a battery pack provided in an embodiment of the present application Figure 1 .like Figure 1 As shown, the battery pack 10 may include a first battery group 1011, a second battery group 1012 and a protection device 102. The first battery group 1011 and the second battery group 1012 are connected in series via the protection device 102.

[0069] In the embodiments of the present application, Figure 1 As shown, it is assumed that the first battery group 1011 may include k battery cells (battery cell 1-1, battery cell 1-2, ..., battery cell 1-k), and the second battery group 1012 may include y battery cells (battery cell 1-1, battery cell 1-2, ..., battery cell 1-y), and the k battery cells are connected in series to form the first battery group 1011, and the y battery cells are connected in series to form the second battery group 1012. Wherein, k and y are positive integers. Here, the values ​​of k and y can be the same or different. The values ​​of k and y can be determined according to the breakdown voltage and battery cell voltage of the corresponding battery group.

[0070] In an embodiment of the present application, the protection device 102 may include at least one of a relay, a pyro fuse, a smart fuse, and an electronic fuse (eFuse). Alternatively, the protection device 102 may also include other switch-type devices, as long as they can disconnect the arcing circuit in time when an arcing fault occurs in the battery pack, and there is no limitation on this. Here, the pyro fuse may also be called a smart fuse, which is a high-voltage battery positive electrode fuse. When an arcing fault occurs in the battery pack, the smart fuse uses the heat generated by itself to melt the fuse and instantly disconnect the circuit to avoid short circuit or fire.

[0071] In the embodiment of the present application, by performing fault detection on the battery pack, when it is determined that the battery pack has an arcing fault, by disconnecting the protection device between the arcing circuits, the problem of continuous arcing breakdown due to the arcing fault causing the battery pack to spread and catch fire can be avoided, thereby improving the safety and reliability of the battery pack.

[0072] In another embodiment of the present application, Figure 2 A schematic diagram of a fault detection method provided in an embodiment of the present application Figure 1 .like Figure 2 As shown, the fault detection method may include:

[0073] S201, obtaining at least two air pressure data of a battery pack at different collection times within a preset collection time.

[0074] In an embodiment of the present application, the fault detection method is applied to a battery pack, and the battery pack includes at least two battery groups, and every two battery groups are connected through a protection device.

[0075] In an embodiment of the present application, the battery pack may further include a collection sensor, for example, the collection sensor may be a voltage collection sensor or an air pressure collection sensor. In a possible embodiment, the collection sensor may be an air pressure collection sensor, which is used to collect air pressure data in the battery pack. It should be noted that when the air pressure in the battery pack changes, the air pressure collection sensor will generate a corresponding electrical signal (or called an air pressure electrical signal). This electrical signal may be an analog signal or a data signal. This electrical signal may be converted into air pressure data through the internal mechanism of the air pressure collection sensor, the design of the signal processing circuit, and the data processing algorithm. Here, the air pressure data may be an air pressure value.

[0076] In an embodiment of the present application, the preset collection time can be 1 second or 10 seconds. The value of the preset collection time is determined according to the actual situation, and the air pressure data corresponding to the air pressure change in the battery pack can be collected within the preset time. In addition, the preset collection time can include multiple time periods, each time period can include at least one collection moment, and it can also be understood that the preset collection time includes multiple collection moments, and the collection moments can be set at equal intervals (for example, 10 milliseconds (ms) is a collection moment, 20ms is a collection moment), or can be set at unequal intervals (for example, 10ms is a collection moment, 15ms is a collection moment), and an air pressure data of the corresponding moment can be obtained for each collection moment; here, the collection moment can be set according to the actual situation, and there is no limitation on this.

[0077] In an embodiment of the present application, the air pressure collection sensor can collect multiple electrical signals within a preset collection time and convert the multiple electrical signals into air pressure data corresponding to each of the multiple electrical signals.

[0078] S202: Determine an air pressure statistical result within a preset collection time according to at least two air pressure data.

[0079] In the embodiment of the present application, the air pressure statistics are used to reflect the changes in the air pressure of the battery pack within the preset collection time. Since the arc discharge caused by the arc fault in the battery pack will generate a large amount of heat and gas, the air pressure data of the battery pack will change dramatically. At this time, the air pressure statistics are obtained based on at least two air pressure data, which can reflect the changes in the air pressure of the battery pack within the preset collection time.

[0080] The air pressure statistics may include the air pressure change rate within a preset collection time, such as a first change rate (which may be called air pressure rise) characterizing an increase in air pressure data and / or a second change rate (which may be called air pressure drop) characterizing a decrease in air pressure data; the air pressure statistics may also include an air pressure variance result within a preset collection time.

[0081] In other words, the gas pressure characteristic signal (i.e., gas pressure data) can be used to detect faults in the battery pack, thereby identifying whether the battery pack has an arcing fault.

[0082] S203, determining whether an arcing fault occurs in the battery pack based on the gas pressure statistics within a preset collection time.

[0083] In the embodiment of the present application, the change of the air pressure inside the battery pack can reflect the change of its internal state. For example, when the battery pack has an arc fault, the high temperature of the arc will cause the gas inside the battery pack to expand, thereby causing the air pressure to rise rapidly, and then the air pressure drops rapidly after the rapid increase. Therefore, by monitoring the statistical results of the air pressure inside the battery pack, it can be determined whether the battery pack has an arc fault.

[0084] In some embodiments, the battery pack can be applied to the iron-lithium battery scenario. For the iron-lithium battery, it has a higher energy density, which enables the iron-lithium battery to store more energy in a smaller volume, and it also has good thermal stability, which enables the iron-lithium battery to work normally at higher temperatures without thermal runaway. This high energy density and thermal stability help the iron-lithium battery remain stable under extreme conditions such as high-voltage arcing.

[0085] That is to say, if two battery packs in the iron-lithium battery pack have double-point insulation failure, the voltage reaches the breakdown voltage of the battery pack, resulting in high-voltage arc breakdown, i.e., arc fault. Due to the characteristics of the iron-lithium battery itself, if only one arc fault occurs, the iron-lithium battery can survive it, that is, it will not cause damage to the iron-lithium battery. However, if multiple arc faults occur, the iron-lithium battery will be damaged, and in severe cases, it will cause fire. Therefore, after an arc fault occurs in the iron-lithium battery, it is necessary to identify the occurrence of the arc fault. If an arc fault is identified in the iron-lithium battery, it is necessary to disconnect the protection device placed in the arc circuit and cut off the arc circuit to prevent continuous breakdown from causing the iron-lithium battery to spread and catch fire. Here, the arc circuit refers to a circuit in which an arc discharge occurs between two battery packs due to some reason (such as double-point insulation failure, etc.). This arc discharge may generate high temperature and high pressure, causing damage to the battery pack and surrounding equipment, and even causing fire or explosion.

[0086] It should be noted that in the embodiment of the present application, the battery pack has already had an arcing fault when the air pressure data is obtained, that is, if the battery pack does not have an arcing fault, the air pressure data with large air pressure fluctuations cannot be obtained. The present application determines the air pressure statistics based on the air pressure data, identifies whether the battery pack has an arcing fault through the air pressure statistics, and cuts off the arcing circuit after the battery pack has an arcing fault, to avoid the problem of continuous breakdown causing the battery pack to spread and catch fire.

[0087] The embodiment of the present application provides a fault detection method. Since the arc discharge caused by an arcing fault in a battery pack will generate a large amount of heat and gas, causing the air pressure data of the battery pack to change dramatically, arcing fault identification is performed based on the statistical results of the air pressure data in the battery pack (such as air pressure rise, air pressure drop, or calculated variance of air pressure, etc.). This can not only accurately identify the occurrence of arcing faults, thereby improving the accuracy of arcing fault identification; but also, after identifying that an arcing fault has occurred in the battery pack, the protection device placed in the arcing circuit can be disconnected in time to avoid further expansion and deterioration of the arcing fault of the battery pack, thereby improving the safety and reliability of the battery pack.

[0088] In another embodiment of the present application, the air pressure statistics include the air pressure change rate within a preset collection time. Here, the air pressure change rate refers to the change in air pressure per unit time, which reflects the speed of air pressure change over time and can be expressed in units such as kilopascals per second (kpa / s).

[0089] In the embodiment of the present application, the air pressure change rate can be calculated by the following formula: air pressure change rate = (first air pressure data - second air pressure data) / collection time interval. Among them, the first air pressure data is the air pressure data at the end of the collection time interval, the second air pressure data is the air pressure data at the beginning of the collection time interval, and the collection time interval is the length of the collection time. Here, the length of the collection time interval should be determined according to the application scenario and requirements.

[0090] In the embodiment of the present application, the collection time interval can be the length of the preset collection time, so the air pressure data at the start time of the preset collection time and the air pressure data at the end time of the preset collection time can be obtained to determine the air pressure change rate within the preset collection time. The collection time interval can also be a certain time period within the preset collection time, that is, periodic collection or non-periodic collection is performed within the preset diagnosis time, and the time difference between each two collection moments is a collection time interval.

[0091] In one possible implementation, Figure 3 As shown, after step S202, the fault detection method may further include:

[0092] S301, in response to the air pressure change rate within a preset collection time satisfying a second condition, determining that an arc fault occurs in the battery pack.

[0093] In an embodiment of the present application, the second condition is used to characterize a measurement indicator for judging the occurrence of an arcing fault in a battery pack based on the air pressure change rate, such as a measurement indicator for characterizing a first change rate of an increase in air pressure data, and / or a measurement indicator for characterizing a second change rate of a decrease in air pressure data, etc. If the air pressure change rate within the preset acquisition time satisfies the second condition, it can be determined that an arcing fault has occurred in the battery pack. At this time, the two target battery packs with arcing faults can be determined based on the voltage data of each battery pack in the battery pack, and the protection device between the two target battery packs can be disconnected to protect the battery pack. If the air pressure change rate within the preset acquisition time does not meet the second condition, it can be determined that the battery pack has not experienced an arcing fault.

[0094] In an embodiment of the present application, if the air pressure change rate within the preset collection time does not meet the second condition, the step of obtaining at least two air pressure data of the battery pack within the next preset collection time is re-executed.

[0095] In a possible embodiment, the air pressure change rate includes a first change rate for characterizing the increase in air pressure data; in response to the air pressure change rate within a preset acquisition time satisfying a second condition, determining that an arcing fault has occurred in the battery pack includes: in response to the first change rate being greater than or equal to a preset air pressure rise threshold and lasting for a first preset time, determining that an arcing fault has occurred in the battery pack.

[0096] In the embodiment of the present application, the first change rate may be referred to as air pressure rise, and the first change rate may be calculated by the following formula:

[0097] U = (P1-P2) / t1 (1)

[0098] Wherein, U represents the first change rate, t1 represents the first collection time interval, P1 represents the air pressure data corresponding to the end time of the first collection time interval, and P2 represents the air pressure data corresponding to the start time of the first collection time interval. Here, the preset collection time may include at least one collection time interval, and the first collection time interval is any one of the at least one collection time interval.

[0099] In the embodiment of the present application, at the moment when an arc fault occurs in the battery pack, local heat of two thousand to ten thousand degrees Celsius will be generated. The high temperature generated by the arc causes the gas inside the battery pack to expand rapidly, thereby causing the air pressure inside the battery pack to rise rapidly. At this time, a rapidly increasing air pressure rise (i.e., a first rate of change) will be detected. Furthermore, by detecting whether the first rate of change is greater than a preset air pressure rise threshold and lasts for a first preset time, it can be determined whether an arc fault occurs in the battery pack.

[0100] In the embodiment of the present application, the preset pressure rise threshold can be 15kpa / s or 20kpa / s; the first preset time can be 0.1 second or 0.01 second; the values ​​of the preset pressure rise threshold and the first preset time are determined according to actual conditions. For example, the preset pressure rise threshold is 15kpa / s and the first preset time is 0.1 second; when the first change rate U≥15 is detected and lasts for 0.1 second, it can be identified that the battery pack has an arc fault.

[0101] That is to say, when the first change rate of the rise in air pressure data characterizing the preset acquisition time is greater than or equal to the preset air pressure rise threshold and lasts for the first preset time, it is determined that an arc fault has occurred in the battery pack. Taking into account that an arc fault in the battery pack will cause the air pressure inside the battery pack to rise sharply, arc fault identification can be performed based on the first change rate of the rise in air pressure data, and the occurrence of arc fault can be accurately identified, thereby improving the accuracy of arc fault identification.

[0102] In another possible embodiment, the air pressure change rate includes a second change rate for characterizing a drop in air pressure data, and in response to the air pressure change rate within a preset acquisition time satisfying a second condition, determining that an arcing fault has occurred in the battery pack includes: in response to the second change rate being less than or equal to a preset air pressure drop threshold and lasting for a second preset time, determining that an arcing fault has occurred in the battery pack.

[0103] In the embodiment of the present application, the second change rate may be referred to as air pressure drop, and the second change rate may be calculated by the following formula:

[0104] O = (P3-P4) / t2 (2)

[0105] Wherein, O represents the second change rate, t2 represents the second collection time interval, P3 represents the air pressure data corresponding to the end time of the second collection time interval, and P4 represents the air pressure data corresponding to the start time of the second collection time interval. Here, the preset collection time may include at least one collection time interval, and the second collection time interval is any one of the at least one collection time interval.

[0106] In an embodiment of the present application, a rapidly rising air pressure rise is detected in the battery pack. As the arcing continues, the gas inside the battery pack may be released into the external environment through the exhaust holes or explosion-proof valves and other structures of the battery pack, thereby causing the air pressure to drop rapidly. At this time, the rapidly decreasing air pressure drop will be detected. Therefore, by detecting whether the second change rate is greater than the preset air pressure drop threshold and lasts for the second preset time, it can be determined whether the battery pack has an arcing fault.

[0107] In the embodiment of the present application, the preset pressure drop threshold can be -0.3kpa / s or -0.5kpa / s; the second preset time can be 0.1 second or 0.01 second; the values ​​of the preset pressure drop threshold and the second preset time are determined according to actual conditions. For example, the preset pressure drop threshold is -0.5kpa / s and the second preset time is 0.1 second; when the second change rate O≤-0.5 is detected and lasts for 0.1 second, it can be identified that the battery pack has an arc fault.

[0108] It can be understood that when the second change rate of the air pressure data drop within the preset collection time is less than or equal to the preset air pressure drop threshold and lasts for the second preset time, it is determined that the battery pack has an arcing fault. Considering that the arcing fault in the battery pack will cause the air pressure inside the battery pack to rise sharply and then drop sharply, the arcing fault is identified based on the second change rate of the air pressure data drop, which can also accurately identify the occurrence of the arcing fault and improve the accuracy of arcing fault identification.

[0109] In another possible embodiment, the air pressure change rate includes a first change rate for characterizing an increase in air pressure data and a second change rate for characterizing a decrease in air pressure data; in response to the air pressure change rate within a preset acquisition time satisfying a second condition, determining that an arcing fault occurs in the battery pack includes:

[0110] In response to the first change rate being greater than or equal to a preset gas pressure rise threshold and lasting for a first preset time and the second change rate being less than or equal to a preset gas pressure drop threshold and lasting for a second preset time, it is determined that an arc fault occurs in the battery pack.

[0111] In the embodiment of the present application, if an arc fault occurs in the battery pack, the high temperature generated by the arc causes the gas inside the battery pack to expand rapidly, thereby causing the air pressure to rise rapidly. At this time, a rapidly rising air pressure rise will be detected. As the arc continues, the gas inside the battery pack may be released into the external environment through the exhaust holes or explosion-proof valves of the battery pack, thereby causing the air pressure to drop rapidly. At this time, a rapidly dropping air pressure drop will be detected. In other words, after the air pressure rise is detected, the air pressure drop is detected, and this is used as a basis to determine whether the battery pack has an arc fault. After determining that the battery has an arc fault, disconnecting the protection device between the two target battery packs can prevent the current from continuing to break through the insulating medium and prevent the generation and spread of arc sparks, thereby effectively curbing the spread of fire in the battery pack.

[0112] Exemplarily, after detecting that a first change rate is greater than or equal to a preset pressure rise threshold and lasts for a first preset time, a second change rate is detected to be less than or equal to a preset pressure drop threshold and lasts for a second preset time, it is determined that an arc fault occurs in the battery pack.

[0113] In an embodiment of the present application, after the first change rate characterizing the rise of the air pressure data within the preset acquisition time is greater than or equal to the preset air pressure rise threshold and continues for the first preset time, the second change rate characterizing the decrease of the air pressure data is less than or equal to the preset air pressure drop threshold and continues for the second preset time, it can be determined that an arc fault has occurred in the battery pack. In this way, considering that an arc fault in the battery pack will cause the air pressure inside the battery pack to rise sharply and then drop sharply, the arc fault can also be identified by jointly using the first change rate characterizing the increase of the air pressure data and the second change rate characterizing the decrease of the air pressure data. It is also possible to accurately identify the occurrence of the arc fault, thereby improving the accuracy of arc fault identification.

[0114] The embodiment of the present application provides a fault detection method. When determining whether an arcing fault occurs in a battery pack, the pressure change rate within a preset acquisition time can be used for judgment. For example, if the pressure change rate within the preset time satisfies the second condition, it is determined that an arcing fault occurs in the battery pack. Considering that an arcing fault in a battery pack will cause a sharp change in the air pressure inside the battery pack, the arcing fault judgment is made based on the pressure change rate within the preset acquisition time. This can not only accurately identify the occurrence of an arcing fault, thereby improving the accuracy of arcing fault identification; but also, after identifying an arcing fault in the battery pack, the protective device placed in the arcing circuit can be disconnected in time to prevent the arcing fault of the battery pack from further expanding and worsening, thereby improving the safety and reliability of the battery pack.

[0115] In another embodiment of the present application, the air pressure statistics result includes the air pressure variance result within the preset collection time. Here, the air pressure variance result reflects the discreteness of the air pressure data. If the air pressure variance result is small, it means that the air pressure data is relatively stable and the fluctuation is not large; if the air pressure variance result is large, it means that the air pressure data fluctuates greatly, and the battery pack may have an arcing fault.

[0116] In the embodiment of the present application, when an arcing fault occurs in the battery pack, the high temperature of the electric arc will cause the gas inside the battery pack to expand, thereby causing a rapid increase in air pressure. After the rapid increase in air pressure, the air pressure drops rapidly. In other words, the air pressure data fluctuates greatly at this time. Therefore, it is possible to determine whether the battery has an arcing fault through the air pressure variance result.

[0117] In the embodiment of the present application, the preset acquisition time may include at least two acquisition moments. The time interval between each two acquisition moments (ie, the acquisition time interval) may be greater than or equal to 0.01 seconds. The time interval may be determined based on actual conditions.

[0118] In another possible implementation, Figure 4 As shown, after step S202, the fault detection method may further include:

[0119] S401, in response to the air pressure variance result within a preset collection time satisfying a first condition, determining that an arc fault occurs in the battery pack.

[0120] In an embodiment of the present application, the first condition is used to characterize a measurement indicator for judging the occurrence of an arc fault in a battery pack based on the air pressure variance result, such as a measurement indicator for characterizing the calculated variance corresponding to the air pressure data at at least two acquisition moments, etc. If the air pressure variance result within the preset acquisition time satisfies the first condition, then it can be determined that an arc fault has occurred in the battery pack. At this time, the two target battery packs with arc faults can be determined based on the voltage data of each battery pack in the battery pack, and the protection device between the two target battery packs can be disconnected to protect the battery pack. If the air pressure variance value within the preset acquisition time does not meet the first condition, then it can be determined that the battery pack does not have an arc fault.

[0121] In a possible embodiment, the pressure variance result within the preset acquisition time may include a calculated variance corresponding to the pressure data for characterizing at least two acquisition moments. Accordingly, in response to the pressure variance result within the preset acquisition time satisfying the first condition, determining that the battery pack has an arcing fault includes: in response to the calculated variance being greater than or equal to the preset variance threshold and lasting for a third preset time, determining that the battery pack has an arcing fault.

[0122] In the embodiment of the present application, the calculated variance may be referred to as the air pressure variance value, and the calculated variance may be calculated by the following formula:

[0123] (3)

[0124] Among them, S represents the calculated variance, Indicates the number of air pressure data. Indicates Air pressure data, express The average value corresponding to the air pressure data.

[0125] In an embodiment of the present application, it is assumed that the preset collection time includes setting a collection moments with equal collection time intervals. At this time, a air pressure data can be obtained, and an air pressure variance value is calculated for each m air pressure data. For example, the first air pressure variance value is obtained based on the 1st air pressure data to the mth air pressure data, and the second air pressure data is obtained based on the 2nd air pressure data to the m+1th air pressure data, and so on. The gth air pressure variance value is obtained based on the gth air pressure data to the m+g-1th air pressure data, and whether the battery pack has an arcing fault is determined based on these g air pressure variance values; wherein a is greater than m and g, and a, m and g are all positive integers.

[0126] Exemplarily, the collection time interval is set to 0.01 seconds, and 0.3 seconds of air pressure data is obtained. At this time, 30 air pressure data can be obtained. The first air pressure variance value is obtained based on the air pressure data from 0-0.1 seconds (i.e., the first air pressure data to the tenth air pressure data), the second air pressure variance value is obtained based on the air pressure data from 0.1 seconds to 0.2 seconds (i.e., the 11th air pressure data to the 20th air pressure data), and the third air pressure variance value is obtained based on the air pressure data from 0.2 seconds to 0.3 seconds (i.e., the 21st air pressure data to the 30th air pressure data), and whether the battery pack has an arc fault is determined based on these three air pressure variance values.

[0127] In another example, the collection time interval is set to 0.01 seconds, and 0.3 seconds of air pressure data is obtained. At this time, 30 air pressure data can be obtained. The first air pressure variance value is obtained based on the first air pressure data to the tenth air pressure data, and the second air pressure variance value is obtained based on the second air pressure data to the 11th air pressure data. And so on, the 20th air pressure variance value is obtained based on the 21st air pressure data to the 30th air pressure data, and whether the battery pack has an arc fault is determined based on these 20 air pressure variance values.

[0128] In the implementation of this application, the calculated variance can be called the air pressure variance value; the preset variance threshold can be 10 or 15; the third preset time can be 0.1 second or 0.01 second; the values ​​of the preset variance threshold and the third preset time are determined according to the actual situation. Exemplarily, the preset variance threshold is 15 and the third preset time is 0.1 second. When the air pressure variance value S ≥ 15 is detected and lasts for 0.1 second, it can be determined that the battery pack has an arcing fault. In another example, the preset variance threshold is 10 and the third preset time is 0.3 second. When the air pressure variance value S > 10 is detected and lasts for 0.3 seconds, it can be determined that the battery pack has an arcing fault. When an arcing fault occurs, the two target battery packs with the arcing fault are identified, and the protective device connected between the two target battery packs is disconnected to prevent the arcing fault from continuing to occur and causing safety problems such as battery pack fires.

[0129] Thus, in the embodiment of the present application, since an arcing fault in the battery pack will cause a sharp change in the air pressure inside the battery pack (for example, the air pressure rises sharply and then drops sharply), by performing variance calculation on the air pressure data at at least two acquisition moments, and when the calculated variance is greater than or equal to a preset variance threshold and lasts for a third preset time, it indicates that a large fluctuation has occurred in the air pressure data. At this time, it can be determined that an arcing fault has occurred in the battery pack, thereby improving the accuracy of arcing fault identification.

[0130] In some embodiments, if the calculated variance within the preset collection time does not satisfy or be equal to the preset variance threshold and lasts for a third preset time, the step of obtaining at least two air pressure data of the battery pack within the next preset collection time is re-executed.

[0131] In a possible implementation, before determining whether the pressure variance result within the preset acquisition time satisfies the first condition, it is also possible to first determine whether the pressure change rate within the preset acquisition time satisfies the second condition. In some embodiments, in response to the pressure variance result within the preset acquisition time satisfying the first condition, determining that the battery pack has an arcing fault may include:

[0132] Determine whether the air pressure change rate within the preset collection time satisfies the second condition;

[0133] When the air pressure change rate within the preset collection time does not satisfy the second condition, in response to the air pressure variance result within the preset collection time satisfying the first condition, it is determined that an arc fault occurs in the battery pack.

[0134] In the embodiment of the present application, when determining whether the battery pack has an arcing fault, a pre-judgment can also be made based on the pressure change rate within the preset acquisition time. For example, if the pressure change rate within the preset time does not meet the second condition, it is not determined whether the battery pack has an arcing fault, and it is necessary to further judge based on the pressure variance result within the preset acquisition time. When the pressure variance result within the preset acquisition time meets the first condition, it is determined that the battery pack has an arcing fault. In this way, the use of double judgment can accurately identify the occurrence of an arcing fault, thereby improving the accuracy of arcing fault identification.

[0135] In some embodiments, the method may further include: in response to the air pressure change rate within a preset acquisition time satisfying a second condition, determining that an arcing fault occurs in the battery pack.

[0136] In an embodiment of the present application, if the air pressure change rate within the preset collection time satisfies the second condition, then it can be determined that an arcing fault occurs in the battery pack, and the judgment of the arcing fault can be directly terminated at this time.

[0137] In some embodiments, the method may further include: in response to the air pressure change rate within the preset acquisition time satisfying the second condition, and the air pressure variance result within the preset acquisition time satisfying the first condition, determining that the battery pack has an arcing fault.

[0138] In the embodiment of the present application, a judgment can also be made based on the air pressure change rate and the air pressure variance result within the preset acquisition time. If the air pressure change rate within the preset acquisition time satisfies the second condition, and the air pressure variance result within the preset acquisition time also satisfies the first condition, then it can be determined that an arcing fault has occurred in the battery pack. In this way, the occurrence of an arcing fault can be more accurately identified through double judgment, thereby improving the accuracy of arcing fault identification.

[0139] That is to say, in the embodiment of the present application, if the air pressure change rate within the preset acquisition time meets the second condition and it is determined that the battery pack has an arcing fault, the judgment of the arcing fault can be directly ended, or it can be further judged based on the air pressure variance result within the preset acquisition time. If the air pressure variance result within the preset acquisition time also meets the first condition, it is determined that the battery pack has an arcing fault. In this way, the double judgment can more accurately identify the occurrence of the arcing fault, thereby improving the accuracy of arcing fault identification.

[0140] In another possible implementation, after determining that the air pressure variance result within the preset acquisition time does not meet the first condition, it is also possible to determine whether the air pressure change rate within the preset acquisition time meets the second condition. In some embodiments, when the air pressure variance result within the preset acquisition time does not meet the first condition, in response to the air pressure change rate within the preset acquisition time meeting the second condition, it is determined that the battery pack has an arc fault.

[0141] In the embodiment of the present application, if the air pressure variance result within the preset acquisition time does not meet the first condition, it is necessary to further judge by the air pressure change rate within the preset acquisition time. If the air pressure change rate within the preset time meets the second condition, it is determined that the battery pack has an arcing fault. In this way, if the air pressure variance result within the preset acquisition time does not meet the first condition, it is uncertain whether the battery pack has an arcing fault. At this time, the air pressure change rate within the preset acquisition time is further used to judge the arcing fault. In this way, the use of double judgment can more accurately identify the occurrence of the arcing fault, thereby improving the accuracy of arcing fault identification.

[0142] In an embodiment of the present application, if the air pressure statistical results within the preset collection time meet the first condition and it is determined that the battery pack has an arcing fault, the judgment of the arcing fault can be directly ended, or it can be further judged based on the air pressure change rate within the preset collection time. If the air pressure change rate within the preset collection time also meets the second condition, it is determined that the battery pack has an arcing fault. In this way, the double judgment can more accurately identify the occurrence of the arcing fault, thereby improving the accuracy of arcing fault identification.

[0143] It should be noted that when judging arcing faults based on the air pressure statistics and air pressure change rate within the preset collection time, double judgment can be used here, mainly to avoid the problem of misjudgment of a single judgment. If both judgment results indicate that the corresponding conditions are not met, it can be determined that the battery pack does not have an arcing fault.

[0144] An embodiment of the present application provides a fault detection method. Taking into account that an arcing fault in a battery pack may cause a sharp change in the air pressure inside the battery pack (for example, the air pressure rises sharply and then drops sharply), arcing fault identification is performed based on the air pressure variance result within a preset acquisition time. The air pressure variance result can measure the degree of deviation between a set of air pressure data and its mathematical expectation (i.e., the air pressure mean). At this time, the occurrence of an arcing fault can also be accurately identified, thereby improving the accuracy of arcing fault identification.

[0145] In yet another embodiment of the present application, Figure 5 A schematic diagram of a fault detection method provided in an embodiment of the present application Figure 4 .like Figure 5 As shown, the fault detection method may also include:

[0146] S501, in response to an arcing fault occurring in a battery pack, determining two target battery groups in which arcing faults occur in the battery pack.

[0147] In the embodiment of the present application, after determining that the battery pack has an arcing fault, the voltage of the battery pack is obtained to determine whether the voltage of the battery pack is within the voltage range under normal working conditions. If the voltage of the battery pack exceeds the voltage range, it can be determined that the battery pack has an arcing fault; or it can be determined that the voltage of the battery pack has abnormal voltage fluctuations, such as the voltage of the battery pack continues to rise or fall, or fluctuates frequently, it can be determined that the battery pack has an arcing fault. In other words, the two target battery packs with arcing faults can be determined based on the voltage data of each battery pack in the battery pack.

[0148] S502, sending a control signal to a protection device between two target battery groups, where the control signal is used to disconnect the protection device.

[0149] In an embodiment of the present application, after two target battery packs are determined, a control signal is sent to a protection device between the two target battery packs to disconnect the protection device, thereby disconnecting the arc circuit between the two target battery packs, thereby avoiding the problem of battery pack spreading and catching fire due to continuous arcing breakdown caused by arcing faults, thereby improving the safety and reliability of the battery pack.

[0150] An embodiment of the present application provides a fault detection method. After determining that an arc fault occurs in a battery pack, two target battery groups where the arc fault occurs in the battery are determined, that is, the arc circuit or the fault location is determined, and the protection device placed in the arc circuit is disconnected to prevent the arc fault of the battery pack from further expanding and worsening, thereby ensuring the safety and reliability of the battery pack.

[0151] In another embodiment of the present application, based on the fault detection method of the above embodiment, Table 1 is a battery pack arcing identification strategy table schematically provided in the embodiment of the present application. As shown in Table 1, the battery pack arcing identification strategy may include strategy 1, strategy 2 and strategy 3.

[0152] Table 1

[0153]

[0154] In an embodiment of the present application, the air pressure rises to the first rate of change in the above embodiment, and the air pressure drops to the second rate of change in the above embodiment. In Table 1, the calculation time can be the time taken to obtain the air pressure data and convert it into air pressure statistics, and the judgment time can be the time taken to identify whether the battery pack has an arcing fault based on the air pressure statistics and to identify two target battery packs and disconnect the protection device between the two target battery packs after identifying the arcing fault in the battery pack. The calculation time and the judgment time can also be other values, which are determined according to the actual situation. The identification strategy in Table 1 is explained in detail below:

[0155] Strategy 1: BMS obtains the air pressure signal (i.e., air pressure data) in the battery pack. Here, the air pressure signal can be obtained by converting the air pressure electrical signal collected by the acquisition sensor. The air pressure rise U is calculated by the above formula (1). Usually, when the air pressure rise U ≥ 15 kpa / s, arcing and breakdown will occur in the battery pack. Here, the preset air pressure rise threshold is equal to 15 kpa / s and the first preset time is 0.1 seconds for judgment. When the air pressure rise U ≥ 15 kpa / s and lasts for 0.1 seconds, it is determined that the battery pack has an arcing fault. The BMS will identify the arcing circuit and cut off the protection device placed in the arcing circuit.

[0156] It should be noted that, through experiments, it is determined that when an arc fault occurs in a battery, the maximum value of the gas pressure rise U is 30 kPa / s, so the identification of strategy 1 in Table 1 is a gas pressure rise of 30 kPa / s. In order to speed up the fault detection speed, it is determined that an arc fault occurs in the battery pack when the gas pressure rise U is ≥ 15 kPa / s and lasts for 0.1s.

[0157] Strategy 2: BMS obtains the air pressure signal (i.e., air pressure data) in the battery pack. Here, the air pressure signal can be obtained by converting the air pressure electrical signal collected by the acquisition sensor. The air pressure rise U is calculated by the above formula (1), and the air pressure drop O is calculated by the above formula (2). Under normal circumstances, the air pressure drop O≤-0.3. Here, the preset air pressure rise threshold is equal to 15, the preset air pressure drop threshold is equal to -0.5, and the first preset time length and the second preset time length are both 0.1 seconds for judgment. When the air pressure rise U≥15 and lasts for 0.1 seconds, and the air pressure drop 0≤-0.5 and lasts for 0.1 seconds, the BMS will identify the arcing circuit and disconnect the protection device.

[0158] It should be noted that it is also possible to determine whether the gas pressure drop O meets the conditions to determine whether the battery pack has an arcing fault, and there is no limitation on this.

[0159] It should also be noted that for the need to judge the air pressure rise and air pressure drop, the judgment time needs to be less than 10 seconds. If the battery pack arc fault is not determined within the judgment time in Strategy 2, the steps of Strategy 2 can be executed again, or the steps of Strategy 3 can be executed, or the steps of Strategy 1 can be executed.

[0160] Strategy 3: BMS obtains the air pressure signal (i.e., air pressure data) in the battery pack. The average value is obtained by the air pressure at d time points (i.e., the collection time). Generally, the adjacent time points t≥0.01 seconds. Here, d can be set to a positive integer between 5 and 10; and the air pressure variance value (i.e., calculated variance) is calculated by the above formula (3). Under normal circumstances, if the air pressure variance value S>7, it means that the battery has an arc fault. In the embodiment of the present application, the preset variance threshold is equal to 10. When the BMS detects that the air pressure variance value S≥10 and lasts for B seconds, it is determined that the battery pack has an arc fault. Here, B is the third preset time length. For the value range of the third preset time length, it can be [0.1 seconds, 0.3 seconds]. In the embodiment of the present application, B is 0.3; obtain the air pressure data corresponding to 10 collection times. When the air pressure variance value S>10 and lasts for 0.3 seconds, the BMS will identify the arc circuit and disconnect the protection device. It should be noted that, in actual applications, the air pressure change time caused by the battery arc fault may be less than 0.1 second, and the values ​​of the first preset time, the second preset time and the third preset time are determined according to actual conditions.

[0161] The embodiment of the present application provides a fault detection method, which can also be called a battery pack BMS arcing identification strategy. The above embodiment is used to explain the implementation of the above embodiment in detail, from which it can be seen that the battery pack is identified and judged for arcing through the air pressure characteristic signal (i.e., air pressure data). When the battery pack is identified to have an arcing fault, the protection device placed in the arcing circuit is disconnected, and the arcing circuit is cut off to prevent continuous breakdown from causing the battery pack to spread and catch fire, thereby ensuring the safety of the battery pack.

[0162] Based on the same inventive concept as the above embodiments, Figure 6 The following is a schematic diagram of the structure of a battery management system provided in an embodiment of the present application. Figure 6 As shown, the battery management system 60 may include a collection unit 601 and a processing unit 602, wherein:

[0163] The collection unit 601 is configured to obtain at least two air pressure data of the battery pack at different collection times within a preset collection time;

[0164] The processing unit 602 is configured to determine the air pressure statistics within a preset collection time based on at least two air pressure data, the air pressure statistics are used to reflect the air pressure changes of the battery pack within the preset collection time, and the air pressure statistics include the air pressure variance results within the preset collection time; and in response to the air pressure variance results within the preset collection time satisfying the first condition, determine that the battery pack has an arc fault.

[0165] In the embodiment of the present application, the processing unit 602 may be a controller, which is the core component of battery protection and management in the battery management system 60, and is used to monitor and manage the working state of the battery pack to ensure that the battery pack works under safe and reliable conditions. The controller may be one or more electronic control units (ECUs), which usually include a high-performance microprocessor, analog and digital input and output interfaces, a communication interface (such as a CAN bus), and a power management circuit, etc., and is responsible for monitoring, managing, and protecting the battery cells or modules in the battery pack.

[0166] In some embodiments, the air pressure statistics also include the air pressure change rate within a preset collection time; the processing unit 602 is further configured to determine that an arc fault occurs in the battery pack in response to the air pressure change rate within the preset collection time satisfying a second condition.

[0167] In some embodiments, the air pressure change rate includes a first change rate for characterizing an increase in air pressure data; the processing unit 602 is also configured to determine that an arc fault has occurred in the battery pack in response to the first change rate being greater than or equal to a preset air pressure rise threshold and lasting for a first preset time.

[0168] In some embodiments, the air pressure change rate includes a second change rate for characterizing a drop in air pressure data; the processing unit 602 is further configured to determine that an arc fault has occurred in the battery pack in response to the second change rate being less than or equal to a preset air pressure drop threshold and lasting for a second preset time.

[0169] In some embodiments, the air pressure change rate includes a first change rate for characterizing an increase in air pressure data and a second change rate for characterizing a decrease in air pressure data; the processing unit 602 is also configured to determine that an arc fault has occurred in the battery pack in response to the first change rate being greater than or equal to a preset air pressure rise threshold and lasting for a first preset time and the second change rate being less than or equal to a preset air pressure drop threshold and lasting for a second preset time.

[0170] In some embodiments, the air pressure variance result within a preset collection time includes a calculated variance corresponding to the air pressure data for characterizing at least two collection moments; the processing unit 602 is also configured to determine that an arc fault has occurred in the battery pack in response to the calculated variance being greater than or equal to a preset variance threshold and lasting for a third preset time.

[0171] In some embodiments, the processing unit 602 is further configured to, in response to an arc fault occurring in the battery pack, determine two target battery packs where arc faults occur in the battery pack; and send a control signal to a protection device between the two target battery packs, wherein the control signal is used to disconnect the protection device.

[0172] The embodiment of the present application provides a battery management system, which may include a collection unit and a processing unit. In this way, since the arc discharge caused by the arc fault in the battery pack will generate a large amount of heat and gas, causing the gas pressure data of the battery pack to change sharply, the processing unit performs statistics on at least two gas pressure data obtained by the collection unit, and performs arc fault identification based on the gas pressure statistical results (such as gas pressure rise, gas pressure drop, or calculated variance of gas pressure, etc.), which can not only accurately identify the occurrence of the arc fault, thereby improving the accuracy of arc fault identification; and after identifying the arc fault in the battery pack, the protective device placed in the arc circuit can be disconnected in time to avoid further expansion and deterioration of the arc fault of the battery pack, thereby improving the safety and reliability of the battery pack.

[0173] In another embodiment of the present application, the embodiment of the present application provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed, the steps of the fault detection method described in any one of the aforementioned embodiments are implemented.

[0174] In another embodiment of the present application, the embodiment of the present application further provides a computer program product, including a computer program or instructions, which, when executed by a processor, implements the steps of the fault detection method as described in any one of the aforementioned embodiments.

[0175] In another embodiment of the present application, the embodiment of the present application provides a battery pack, the battery pack comprising at least two battery groups, at least one protection device and the battery management system described in any one of the above embodiments;

[0176] Among them, in at least two battery packs, a protection device is arranged between every two battery packs.

[0177] In some embodiments, the protection device 102 includes at least one of the following: a relay, an instantaneous fuse, a smart fuse, and an electronic fuse.

[0178] In this way, the protection device 102 can adopt a relay, an instantaneous fuse, a smart fuse or an electronic fuse, etc., which can disconnect the arc circuit in time after identifying the arc fault in the battery pack, so as to avoid the arc fault of the battery pack from further expanding and worsening, thereby improving the safety and reliability of the battery pack.

[0179] In some embodiments, Figure 7 A schematic diagram of the structure of a battery pack provided in an embodiment of the present application Figure 2 .like Figure 7 As shown, the battery pack 10 may include a first battery group 1011 , a second battery group 1012 , a protection device 102 , and a battery management system 60 .

[0180] In an embodiment of the present application, the protection device 102 is connected in series between the first battery group 1011 and the second battery group 1012, and the battery management system 60 is connected to the protection device 102 for sending a control signal to the protection device 102 to disconnect the protection device 102 when an arc fault is detected in the battery pack 10.

[0181] In some embodiments, continuing as Figure 7 As shown, the battery pack 10 also includes a collection sensor 701; the collection sensor 701 is configured to collect air pressure data of the battery pack and send at least two air pressure data collected within a preset collection time to the battery management system.

[0182] That is, the air pressure data of the battery pack is collected by the collection sensor, so that the battery management system can identify whether an arc fault occurs in the battery pack according to at least two air pressure data collected.

[0183] An embodiment of the present application provides a battery pack, which obtains air pressure statistical data by statistically processing the air pressure data of the battery pack, and can accurately determine whether the battery pack has an arcing fault based on the air pressure statistical data, such as air pressure rise, air pressure drop, or calculated variance of the air pressure, thereby improving the accuracy of arcing fault judgment; and after determining that the battery pack has an arcing fault, the arcing circuit is cut off by disconnecting the protection device, thereby preventing the arcing fault from further expanding and worsening, thereby ensuring the safety and reliability of the battery pack.

[0184] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, devices, equipment, or computer program products. Therefore, the present application may take the form of hardware embodiments, software embodiments, or embodiments combining software and hardware. Moreover, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) containing computer-usable program codes.

[0185] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0186] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0187] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0188] It should be noted that, in this application, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, product or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, product or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, product or device including the element.

[0189] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0190] The methods disclosed in several method embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments.

[0191] The features disclosed in several product embodiments provided in this application can be arbitrarily combined without conflict to obtain new product embodiments.

[0192] The features disclosed in several method or device embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments or device embodiments.

[0193] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A fault detection method, characterized in that: The fault detection method comprises: Obtain at least two air pressure data of the battery pack at different collection times within a preset collection time; Determine, according to the at least two air pressure data, an air pressure statistical result within the preset collection time, wherein the air pressure statistical result is used to reflect the air pressure change of the battery pack within the preset collection time, and the air pressure statistical result includes an air pressure variance result within the preset collection time; In response to the air pressure variance result within the preset collection time satisfying a first condition, determining that an arcing fault occurs in the battery pack; The air pressure statistics result further includes the air pressure change rate within the preset collection time, and the air pressure change rate includes a second change rate for characterizing the decrease of air pressure data; the fault detection method further includes: When the air pressure variance result within the preset collection time does not meet the first condition, in response to the second change rate being less than or equal to the preset air pressure drop threshold and lasting for a second preset time, it is determined that the battery pack has an arcing fault.

2. The fault detection method according to claim 1, characterized in that: The air pressure change rate also includes a first change rate for characterizing an increase in air pressure data; The fault detection method further comprises: When the air pressure variance result within the preset collection time does not meet the first condition, in response to the first change rate being greater than or equal to the preset air pressure rise threshold and lasting for the first preset time, and the second change rate being less than or equal to the preset air pressure drop threshold and lasting for the second preset time, it is determined that the battery pack has an arc fault.

3. The fault detection method according to claim 1, characterized in that: The step of determining that an arcing fault occurs in the battery pack in response to the air pressure variance result within the preset acquisition time satisfying a first condition includes: Determining whether the air pressure change rate within the preset collection time satisfies the second condition; When the air pressure change rate within the preset acquisition time does not satisfy the second condition, in response to the air pressure variance result within the preset acquisition time satisfying the first condition, it is determined that an arc fault occurs in the battery pack.

4. The fault detection method according to claim 1, characterized in that: The air pressure variance result within the preset acquisition time includes a calculated variance corresponding to the air pressure data for characterizing at least two acquisition moments; The step of determining that an arcing fault occurs in the battery pack in response to the air pressure variance result within the preset acquisition time satisfying a first condition includes: In response to the calculated variance being greater than or equal to a preset variance threshold and lasting for a third preset time, it is determined that an arc fault occurs in the battery pack.

5. The fault detection method according to any one of claims 1 to 4, characterized in that: The fault detection method further comprises: In response to an arcing fault occurring in the battery pack, determining two target battery groups in which the arcing fault occurs in the battery pack; A control signal is sent to a protection device between the two target battery groups, wherein the control signal is used to disconnect the protection device.

6. A battery management system, characterized in that: The battery management system includes a collection unit and a processing unit, wherein: The acquisition unit is configured to acquire at least two air pressure data of the battery pack at different acquisition times within a preset acquisition time; The processing unit is configured to determine, based on the at least two air pressure data, an air pressure statistical result within the preset collection time, the air pressure statistical result being used to reflect the air pressure change of the battery pack within the preset collection time, the air pressure statistical result including an air pressure variance result within the preset collection time; and in response to the air pressure variance result within the preset collection time satisfying a first condition, determine that an arc fault occurs in the battery pack; Among them, the air pressure statistical result also includes the air pressure change rate within the preset collection time, and the air pressure change rate includes a second change rate for characterizing the drop in air pressure data; the processing unit is also configured to, when the air pressure variance result within the preset collection time does not meet the first condition, in response to the second change rate being less than or equal to a preset air pressure drop threshold and lasting for a second preset time, determine that the battery pack has an arc fault.

7. A battery pack, characterized in that: The battery pack comprises at least two battery packs, at least one protection device and a battery management system as claimed in claim 6; Among the at least two battery packs, the protection device is arranged between every two battery packs.

8. The battery pack according to claim 7, characterized in that: The protection device includes at least one of the following: a relay, an instantaneous fuse, an intelligent fuse and an electronic fuse.

9. The battery pack according to claim 8, characterized in that: The battery pack also includes a collection sensor, wherein: The acquisition sensor is configured to collect air pressure data of the battery pack and send at least two air pressure data collected within a preset acquisition time to the battery management system.

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