Battery management system, heating circuit control method, battery system and equipment

Abstract

The embodiment of the present application provides a battery management system, a control method for a heating circuit, a battery system and equipment, the battery management system comprising: a heating circuit including at least one heating film and at least one switching element, which is used to connect to the total positive electrode and the total negative electrode of the battery system; a controller, which is used to control each of the at least one switching element to be turned on, so that the heating film heats the battery cells in the battery system; in the process of the heating film heating the battery cells in the battery system, the electrical signal in the heating circuit is collected; based on the electrical signals collected at multiple sampling time points, the electrical signal characteristic value corresponding to each time point in the multiple sampling time points is determined; based on the electrical signal characteristic value corresponding to at least one of the time points, any number of the switching elements in the at least one switching element are controlled to be turned off, so that the heating film stops heating the battery cells. In this way, the working requirements of the heating circuit can be better met, thereby improving the safety and performance of the battery product.

Description

Technical Field

[0001] The present application relates to the field of battery pack safety technology, and in particular to a battery management system, a control method for a heating circuit, a battery system and equipment. Background Art

[0002] This section is intended to provide a background or context for the embodiments of the present application. No description herein is admitted to be prior art by virtue of its inclusion in this section.

[0003] In the related art, for battery products with poor low-temperature performance, a heating film is generally used on the side of the battery cell for heating. The heating film may be partially damaged or thinned during use. When the resistance wire of the heating film is disconnected, arcing may occur, resulting in insulation failure between the battery cells, causing arcing between the battery cells, and then causing the battery cells to break down and spread and catch fire, thereby affecting the performance and safety of the battery product.

[0004] Therefore, how to improve the safety of battery products is an urgent problem to be solved. Summary of the invention

[0005] In view of this, the embodiments of the present application hope to provide a battery management system, a control method for a heating circuit, a battery system and equipment, which can more accurately and timely control the shutdown of the switching elements in the heating circuit to better meet the working requirements of the heating circuit, so that the heating film can stop heating the battery cell more accurately and timely, thereby improving the safety and performance of the battery product.

[0006] A first aspect of an embodiment of the present application provides a battery management system, the battery management system comprising:

[0007] A heating circuit, comprising at least one heating film and at least one switching element, wherein the at least one heating film and the at least one switching element are connected in series, and the heating circuit is used to connect to the total positive electrode and the total negative electrode of the battery system;

[0008] A controller is used to: control each of at least one switch element to be turned on so that a heating film heats a battery cell in a battery system; collect electrical signals in a heating circuit during the process of the heating film heating a battery cell in the battery system; the electrical signals include current signals, and / or current signals and voltage signals of at least one heating film; determine the electrical signal characteristic value corresponding to each of the multiple sampling time points based on the electrical signals collected at multiple sampling time points; and control any number of the switch elements in at least one switch element to be turned off based on the electrical signal characteristic value corresponding to at least one time point, so that the heating film stops heating the battery cell.

[0009] In the embodiment of the present application, in the battery management system, the controller controls each switch element in at least one switch element of the heating circuit to be turned on, so that at least one heating film heats the battery cell in the battery system, that is, the heating film works; during the operation of the heating film, the controller collects the electrical signal in the heating circuit, and the electrical signal includes the current signal, and / or the current signal and the voltage signal of the heating film; the controller determines the electrical signal characteristic value corresponding to each time point in the multiple sampling time points based on the electrical signal collected at multiple sampling time points; based on the electrical signal characteristic value corresponding to at least one time point, controls any number of switch elements in at least one switch element of the heating circuit to be turned off, so that the heating film stops heating the battery cell, that is, the heating film stops working. In this way, since the electrical signals collected at multiple sampling time points can more accurately reflect the working state of the heating circuit, based on the electrical signal characteristic value corresponding to at least one time point determined according to the electrical signals collected at multiple sampling time points, the switching element in the heating circuit can be more accurately and timely controlled to be turned off, so as to better meet the working requirements of the heating circuit, so that the heating film can stop heating the battery cell more accurately and timely, thereby improving the safety and performance of the battery product.

[0010] In some embodiments, the characteristic value of the electrical signal includes a characteristic value of resistance, and the controller can also be used to: determine the resistance value corresponding to each of a plurality of sampling time points based on the current signal and the voltage signal of at least one heating film; for each of the plurality of sampling time points, determine the characteristic resistance value corresponding to the time point based on the resistance values ​​corresponding to other time points prior to the time point.

[0011] In the above embodiment, the controller determines the resistance value corresponding to each time point in a plurality of sampling time points based on the current signal and the voltage signal of the heating film; and determines the resistance characteristic value corresponding to each time point based on the resistance values ​​corresponding to other time points prior to each time point. In this way, since the resistance signal in the heating circuit is usually relatively stable and not easily affected by temperature, battery charging process, etc., during the operation of the heating film, the resistance characteristic value determined based on the resistance value can more accurately reflect the working state of the heating circuit, thereby further improving the accuracy and timeliness of shutting down the switch element in the heating circuit, so as to further improve the safety and performance of the battery product.

[0012] In some embodiments, the controller may also be configured to: in response to a resistance characteristic value corresponding to any time point among a plurality of sampling time points being greater than or equal to a first resistance threshold, control any number of switch elements in at least one switch element to turn off.

[0013] In the above embodiment, when the resistance characteristic value corresponding to any time point in the multiple sampling time points is greater than or equal to the first resistance threshold, the controller controls any number of switch elements in at least one switch element to turn off. In this way, the battery management system can more accurately identify the working state of the heating circuit based on the magnitude relationship between the resistance characteristic value and the first resistance threshold, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0014] In some embodiments, the controller may also be configured to: in response to the number of time points at which the resistance characteristic value is greater than or equal to the second resistance threshold being greater than or equal to a first number threshold, control any number of switch elements in at least one switch element to turn off.

[0015] In the above embodiment, the controller controls any number of switch elements in at least one switch element to be turned off when the number of time points at which the characteristic resistance value is greater than or equal to the second resistance threshold value is greater than or equal to the first number threshold value. In this way, since the resistance values ​​collected at different times have normal fluctuations, and considering that the characteristic resistance value obtained based on the resistance value has normal fluctuations, the working state of the heating circuit can be more accurately identified according to the size relationship between the number of time points at which the characteristic resistance value is greater than or equal to the second resistance threshold value and the first number threshold value, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0016] In some embodiments, the controller can also be used to: in response to the number of time points when the resistance characteristic value is greater than or equal to the third resistance threshold being greater than or equal to a second number threshold, and the time points when the resistance characteristic value is greater than or equal to the third resistance threshold being within a first time length, control any number of switch elements in at least one switch element to turn off.

[0017] In the above embodiment, the controller controls any number of switch elements in at least one switch element to turn off when the number of time points at which the characteristic resistance value is greater than or equal to the third resistance threshold is greater than or equal to the second number threshold, and the time points at which the characteristic resistance value is greater than or equal to the third resistance threshold are within the first time period. In this way, based on the size relationship between the number of time points at which the characteristic resistance value is greater than or equal to the third resistance threshold within the set time period and the second number threshold, the working state of the heating circuit can be more accurately identified, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0018] In some embodiments, the electrical signal characteristic value includes a current characteristic value, and the controller can also be used to: for each time point among multiple sampling time points, determine the current characteristic value corresponding to the time point based on the current values ​​corresponding to other time points before the time point.

[0019] In the above embodiment, the controller determines the current characteristic value corresponding to each time point based on the current values ​​corresponding to other time points prior to each time point in the multiple sampling time points. In this way, since the heating film gradually ages during use, and the current signal is less affected by the aging of the heating film, during the operation of the heating film, the current characteristic value determined based on the current value can more accurately reflect the working state of the heating circuit, thereby further improving the accuracy and timeliness of shutting off the switch element in the heating circuit, so as to further improve the safety and performance of the battery product.

[0020] In some embodiments, the controller may also be used to: determine the variance between current values ​​corresponding to multiple other time points prior to each time point in the multiple sampling time points as the current characteristic value corresponding to the time point.

[0021] In the above embodiment, the controller determines the current characteristic value corresponding to each time point based on the variance between the current values ​​corresponding to multiple other time points prior to each time point in the multiple sampling time points. In this way, considering the influence of normal fluctuations in the current value during the operation of the heating film, the current characteristic value determined by the variance of the current value can more accurately reflect the working state of the heating circuit, thereby further improving the accuracy and timeliness of shutting down the switch element in the heating circuit, so as to further improve the safety and performance of the battery product.

[0022] In some embodiments, the controller may also be configured to: in response to a current characteristic value corresponding to any time point among a plurality of sampling time points being greater than or equal to a first variance threshold, control any number of switch elements in at least one switch element to turn off.

[0023] In the above embodiment, when the current characteristic value corresponding to any time point in the multiple sampling time points is greater than or equal to the first variance threshold, the controller controls any number of switch elements in at least one switch element to turn off. In this way, the battery management system can more accurately identify the working state of the heating circuit based on the magnitude relationship between the current characteristic value and the first variance threshold, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0024] In some embodiments, the controller may also be configured to: in response to the number of time points at which the current characteristic value is greater than or equal to the second variance threshold being greater than or equal to a third number threshold, control any number of the at least one switching element to turn off.

[0025] In the above embodiment, the controller controls any number of switch elements in at least one switch element to turn off when the number of time points at which the current characteristic value is greater than or equal to the second variance threshold is greater than or equal to the third number threshold. In this way, since the current values ​​collected at different times have normal fluctuations, and considering that the current characteristic value obtained based on the current value has normal fluctuations, the working state of the heating circuit can be more accurately identified based on the relationship between the number of time points at which the current characteristic value is greater than or equal to the second variance threshold and the third number threshold, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0026] In some embodiments, the controller can also be used to: in response to the number of time points when the current characteristic value is greater than or equal to the third difference threshold being greater than or equal to a fourth quantity threshold, and the time points when the current characteristic value is greater than or equal to the third difference threshold being within the second time length, control any number of switch elements in at least one switch element to turn off.

[0027] In the above embodiment, the controller controls any number of switch elements in at least one switch element to turn off when the number of time points at which the current characteristic value is greater than or equal to the third difference threshold is greater than or equal to the fourth number threshold, and the time points at which the current characteristic value is greater than or equal to the third difference threshold are within the first time period. In this way, based on the size relationship between the number of time points at which the current characteristic value is greater than or equal to the third difference threshold within the set time period and the fourth number threshold, the working state of the heating circuit can be more accurately identified, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0028] In some embodiments, the characteristic value of the electrical signal includes the absolute value of the current value, and the controller can also be used to: in response to the absolute value of the current value corresponding to any time point in multiple sampling time points being less than or equal to the first current threshold, control any number of switch elements in at least one switch element to turn off.

[0029] In the above embodiment, when the absolute value of the current value corresponding to any time point in the multiple sampling time points is less than or equal to the first current threshold, the controller controls any number of switch elements in at least one switch element to be turned off. In this way, the battery management system can more accurately identify the working state of the heating circuit based on the relationship between the absolute value of the current value and the first current threshold, thereby further improving the accuracy of turning off the switch elements in the heating circuit; on the other hand, since the calculation process of obtaining the absolute value of the current value corresponding to the sampling time point is relatively simple, identifying the working state of the heating circuit based on the absolute value of the current value corresponding to the sampling time point can improve the timeliness of turning off the switch elements in the heating circuit, and further improve the safety and performance of the battery product.

[0030] In some embodiments, the characteristic value of the electrical signal includes the absolute value of the current value, and the controller can also be used to: in response to the number of time points when the absolute value of the current value is less than or equal to the second current threshold being greater than or equal to a fifth quantity threshold, control any number of switching elements in at least one switching element to turn off.

[0031] In the above embodiment, the controller controls any number of switch elements in at least one switch element to turn off when the number of time points at which the absolute value of the current value is less than or equal to the second current threshold is greater than or equal to the fifth number threshold. In this way, since the current values ​​collected at different times have normal fluctuations, and considering that the absolute value of the current value obtained based on the current value has normal fluctuations, the working state of the heating circuit can be more accurately identified according to the size relationship between the number of time points at which the absolute value of the current value is less than or equal to the second current threshold and the number of time points at which the absolute value of the current value is less than or equal to the second current threshold is greater than or equal to the fifth number threshold, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0032] In some embodiments, the characteristic value of the electrical signal includes the absolute value of the current value, and the controller can also be used to: in response to the number of time points when the absolute value of the current value is less than or equal to the third current threshold being greater than or equal to a sixth number threshold, and the time points when the absolute value of the current value is less than or equal to the third current threshold being within a third time length, control any number of switching elements in at least one switching element to turn off.

[0033] In the above embodiment, the controller controls any number of switch elements in at least one switch element to be turned off when the number of time points at which the absolute value of the current value is less than or equal to the third current threshold is greater than or equal to the sixth number threshold, and the time points at which the absolute value of the current value is less than or equal to the third current threshold is within the third time period. In this way, based on the size relationship between the number of time points at which the absolute value of the current value is less than or equal to the third current threshold within the set time period and the sixth number threshold, the working state of the heating circuit can be more accurately identified, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0034] In some embodiments, the characteristic value of the electrical signal includes a resistance characteristic value and a current characteristic value, and the controller can also be used to: determine the resistance value corresponding to each time point in a plurality of sampling time points based on the current signal and the voltage signal of at least one heating film; for each time point in a plurality of sampling time points, determine the resistance characteristic value corresponding to the time point based on the resistance values ​​corresponding to other time points prior to the time point; for each time point in a plurality of sampling time points, determine the current characteristic value corresponding to the time point based on the current values ​​corresponding to other time points prior to the time point.

[0035] In the above embodiment, the controller determines the resistance characteristic value and the current characteristic value corresponding to each time point in multiple sampling time points based on the current signal and the voltage signal of at least one heating film. In this way, the working state of the heating current is identified based on at least two characteristic values, which is not easily affected by the inaccurate identification caused by the abnormality of a single characteristic value, and can further improve the accuracy and timeliness of shutting down the switch element in the heating circuit, so as to further improve the safety and performance of the battery product.

[0036] In some embodiments, the controller may also be used to: determine the variance between the current values ​​corresponding to multiple other time points prior to each time point in the multiple sampling time points as the current characteristic value corresponding to the time point; in response to the resistance characteristic value corresponding to at least one time point in the multiple sampling time points satisfying the first characteristic condition, and the current characteristic value corresponding to at least one time point in the multiple sampling time points satisfying the second characteristic condition, control any number of switch elements in the at least one switch element to turn off;

[0037] The first characteristic condition includes one of the following:

[0038] The resistance characteristic value corresponding to any time point among the multiple sampling time points is greater than or equal to the fourth resistance threshold;

[0039] The number of time points at which the resistance characteristic value is greater than or equal to the fifth resistance threshold is greater than or equal to a seventh number threshold;

[0040] The number of time points at which the characteristic resistance value is greater than or equal to the sixth resistance threshold is greater than or equal to an eighth number threshold, and the time points at which the characteristic resistance value is greater than or equal to the sixth resistance threshold are within a fourth time duration;

[0041] The second characteristic condition includes one of the following:

[0042] The current characteristic value corresponding to any time point among the multiple sampling time points is greater than or equal to the fourth variance threshold;

[0043] The number of time points at which the current characteristic value is greater than or equal to the fifth variance threshold is greater than or equal to a ninth number threshold;

[0044] The number of time points at which the current characteristic value is greater than or equal to the sixth variance threshold is greater than or equal to the tenth number threshold, and the time points at which the current characteristic value is greater than or equal to the sixth variance threshold are within the fifth time length.

[0045] In the above embodiment, the controller determines the current characteristic value based on the variance between the current values ​​corresponding to multiple other time points prior to any time point among the multiple sampling time points; when the resistance characteristic value at any time point among the multiple sampling time points satisfies the first characteristic condition, and the current characteristic value corresponding to the time point satisfies the second characteristic condition, any number of switch elements in at least one switch element are controlled to be turned off; the first characteristic condition includes that the resistance characteristic value corresponding to the time point satisfies the numerical condition, the number of sampling time points at which the resistance characteristic value satisfies the numerical condition satisfies the quantity condition, the number of sampling time points at which the resistance characteristic value satisfies the numerical condition satisfies the quantity condition, and the collection time length for collecting the sampling time points that meet the quantity condition satisfies the time length condition; the second characteristic condition includes that the current characteristic value corresponding to the time point satisfies the numerical condition, the number of sampling time points at which the current characteristic value satisfies the numerical condition satisfies the quantity condition, the number of sampling time points at which the current characteristic value satisfies the numerical condition satisfies the quantity condition, and the collection time length for collecting the sampling time points that meet the quantity condition satisfies the time length condition. In this way, the battery management system can more accurately identify the working state of the heating circuit based on the size relationship between the resistance characteristic value and the corresponding characteristic value threshold, the current value variance and the variance threshold, the number of sampling time points at which the characteristic value and the corresponding characteristic value threshold satisfy the size relationship, and the duration between the sampling time points at which the characteristic value and the corresponding characteristic value threshold satisfy the size relationship, thereby further improving the accuracy and timeliness of shutting off the switching element in the heating circuit; on the other hand, combined with the variance of the current value, the impact of normal fluctuations in the current value on the judgment of the working state of the heating circuit can be reduced, thereby further improving the accuracy of shutting off the switching element in the heating circuit, so as to further improve the safety and performance of the battery product.

[0046] In some embodiments, the current characteristic value includes an absolute value of the current value, and the controller may further be used to: in response to the resistance characteristic value corresponding to at least one time point in the multiple sampling time points satisfying a third characteristic condition, and the absolute value of the current value corresponding to at least one time point in the multiple sampling time points satisfying a fourth characteristic condition, control any number of switch elements in the at least one switch element to turn off;

[0047] The third characteristic condition includes one of the following:

[0048] The resistance characteristic value corresponding to any time point among the multiple sampling time points is greater than or equal to the seventh resistance threshold;

[0049] The number of time points at which the resistance characteristic value is greater than or equal to the eighth resistance threshold value is greater than or equal to the eleventh number threshold value;

[0050] The number of time points at which the resistance characteristic value is greater than or equal to the ninth resistance threshold value is greater than or equal to the twelfth number threshold value, and the time points at which the resistance characteristic value is greater than or equal to the ninth resistance threshold value are within the sixth time length;

[0051] The fourth characteristic condition includes one of the following:

[0052] The absolute value of the current value corresponding to any time point among the multiple sampling time points is less than or equal to the fourth current threshold;

[0053] The number of time points at which the absolute value of the current value is less than or equal to the fifth current threshold is greater than or equal to the thirteenth number threshold;

[0054] The number of time points at which the absolute value of the current value is less than or equal to the sixth current threshold is greater than or equal to the fourteenth number threshold, and the time points at which the absolute value of the current value is less than or equal to the sixth current threshold are within the seventh time length.

[0055] In the above embodiment, when the resistance characteristic value corresponding to at least one time point among multiple sampling time points satisfies the third characteristic condition, and the absolute value of the current value corresponding to the time point satisfies the fourth characteristic condition, any number of switch elements in at least one switch element are controlled to be turned off; the third characteristic condition includes that the resistance characteristic value corresponding to the time point satisfies the numerical condition, the number of sampling time points at which the resistance characteristic value satisfies the numerical condition satisfies the quantity condition, the number of sampling time points at which the resistance characteristic value satisfies the numerical condition satisfies the quantity condition, and the collection time length for collecting the sampling time points that meet the quantity condition satisfies the time length condition; the fourth characteristic condition includes that the absolute value of the current value corresponding to the time point satisfies the numerical condition, the number of sampling time points at which the absolute value of the current value satisfies the numerical condition satisfies the quantity condition, the number of sampling time points at which the absolute value of the current value satisfies the numerical condition satisfies the quantity condition, and the collection time length for collecting the sampling time points that meet the quantity condition satisfies the time length condition. In this way, the battery management system can more accurately identify the working state of the heating circuit based on the relationship between the resistance characteristic value and the corresponding characteristic value threshold, the absolute value of the current value and the current threshold, the number of sampling time points at which the characteristic value and the corresponding characteristic value threshold satisfy the relationship, and the duration between the sampling time points at which the characteristic value and the corresponding characteristic value threshold satisfy the relationship, thereby further improving the accuracy and timeliness of shutting down the switching element in the heating circuit; on the other hand, since the calculation process of obtaining the absolute value of the current value corresponding to the sampling time point is relatively simple, identifying the working state of the heating circuit based on the absolute value of the current value corresponding to the sampling time point can further improve the timeliness of shutting down the switching element in the heating circuit, thereby further improving the safety and performance of the battery product.

[0056] In some embodiments, the heating film is disposed on the surface of at least one group of battery cells, and an insulating protective layer is disposed between the heating film and the surface of the battery cells.

[0057] In the above embodiment, an insulating protective layer is provided between the heating film and the surface of the battery cell. In this way, on the one hand, the insulation safety of the battery product can be improved; on the other hand, the time before the insulation failure between the battery cells due to damage to the heating film can be prolonged, thereby prolonging the time to identify the working state of the heating circuit before the insulation failure between the battery cells, and more accurately and timely controlling the switching element in the heating circuit to turn off, so as to better meet the working requirements of the heating circuit, so that the heating film can stop heating the battery cell more accurately and timely, thereby improving the safety and performance of the battery product.

[0058] A second aspect of an embodiment of the present application provides a method for controlling a heating circuit, the method for controlling a heating circuit comprising:

[0059] Controlling each of the at least one switching element to be turned on so that the heating film heats the battery cells in the battery system;

[0060] In the process of heating the battery cells in the battery system by the heating film, collecting the electrical signal in the heating circuit; the electrical signal includes a current signal, and / or a current signal and a voltage signal of at least one heating film;

[0061] Based on the electrical signals collected at the multiple sampling time points, determining the electrical signal characteristic value corresponding to each time point in the multiple sampling time points;

[0062] Based on the electrical signal characteristic values ​​respectively corresponding to at least one time point, any number of switch elements in the at least one switch element are controlled to be turned off, so that the heating film stops heating the battery cell.

[0063] A third aspect of an embodiment of the present application provides a battery system, which includes: at least one battery cell and the above-mentioned battery management system.

[0064] A fourth aspect of an embodiment of the present application provides an electrical device, which includes: the above-mentioned battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 A schematic diagram of a heating film loop insulation failure process provided by an embodiment of the present application;

[0066] Figure 2 A schematic diagram of the structure of a battery management system provided in an embodiment of the present application;

[0067] Figure 3 A schematic diagram of the composition structure of a heating circuit provided in an embodiment of the present application Figure 1 ;

[0068] Figure 4 A schematic diagram of the structure of an electrical box provided in an embodiment of the present application;

[0069] Figure 5 A schematic diagram of the composition structure of a heating circuit provided in an embodiment of the present application Figure 2 ;

[0070] Figure 6 A schematic diagram of a process flow for solving an abnormal working state of a heating circuit provided in an embodiment of the present application;

[0071] Figure 7 A schematic diagram of an implementation process of a heating circuit control method provided in an embodiment of the present application Figure 1 ;

[0072] Figure 8 A schematic diagram of an implementation process of a heating circuit control method provided in an embodiment of the present application Figure 2 ;

[0073] Fig. 9A schematic diagram of the structure of a battery system provided in an embodiment of the present application;

[0074] Fig.10 A schematic diagram of the composition structure of an electrical device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0075] It should be noted that, in the absence of conflict, the embodiments and technical features in the embodiments of the present application can be combined with each other, and the detailed description in the specific implementation method should be understood as an explanation of the purpose of the present application and should not be regarded as an improper limitation on the present application.

[0076] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions.

[0077] In the description of the embodiments of the present application, the technical terms "first", "second", "third", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0078] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments 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.

[0079] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0080] In the description of the embodiments of the present application, the orientation or position relationship indicated by technical terms such as "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "circumferential", "height direction", "first direction", and "second direction" are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed, operated or used in a specific orientation. Therefore, they should not be understood as limitations on the embodiments of the present application.

[0081] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0082] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the technical term "contact" should be understood in a broad sense, and may be direct contact or contact through an intermediate medium layer. It may be contact with essentially no interaction force between the two contacting parties, or it may be contact with interaction force between the two contacting parties.

[0083] During the use of the heating film, there is a phenomenon that the resistance wire is constantly reduced. In the case where the heating film is attached to the opposite sides of two adjacent rows of battery cells in the battery module, when the resistance wire of the heating film on one side is disconnected, the heating film on that side will arc, thereby damaging the heating film on the opposite side and the battery cell insulation glue on this side, causing arc damage to the heating film on the opposite side, which further leads to insulation failure between the battery cells, arcing between the two rows of battery cells, and ultimately battery failure.

[0084] For example, Figure 1 As shown, t 0 At this moment, the resistance wire of the heating film on one side is disconnected to generate arc, and the heating film on this side begins to be damaged by arcing; t 1 At this moment, the heating film on this side damages the heating film on the opposite side and the insulating glue of the battery cell on this side, causing the heating film on the opposite side to produce arcing; t 2 At this moment, the heating film on this side and the heating film on the opposite side are damaged by arcing, thereby damaging the insulating glue of the battery cells corresponding to the heating films on both sides, resulting in insulation failure between the battery cells, battery cell shell breakdown, arcing between the battery cells, fire and other problems;t 3 moment, the battery fails.

[0085] The present application embodiment provides a battery management system, such as Figure 2 As shown, the battery management system 10 includes: a heating circuit 11 and a controller 12, the heating circuit 11 includes a heating film 13 and a switch element 14;

[0086] A heating circuit, comprising at least one heating film and at least one switching element, wherein the at least one heating film and the at least one switching element are connected in series, and the heating circuit is used to connect to the total positive electrode and the total negative electrode of the battery system;

[0087] A controller, used to: control each of the at least one switch element to be turned on so that the heating film heats the battery cells in the battery system;

[0088] In the process of heating the battery cells in the battery system by the heating film, collecting the electrical signal in the heating circuit; the electrical signal includes a current signal, and / or a current signal and a voltage signal of at least one heating film;

[0089] Based on the electrical signals collected at multiple sampling time points, any number of the at least one switching element is controlled to be turned off, so that the heating film stops heating the battery cell.

[0090] Here, the switch element is a device for controlling the on and off of current in a circuit, and may include but is not limited to at least one of a solid-state switch, a magnetic switch, etc. The magnetic switch may include but is not limited to a reed relay, a Hall sensor, etc.

[0091] The battery system may include a plurality of battery modules arranged adjacent to each other, and the heating film may be attached to the side of each battery module and separate the battery cell insulating glue between adjacent battery modules.

[0092] The battery module may include but is not limited to at least one of a square-shell battery module, a cylindrical battery module, a soft-pack battery module, a series battery module, a parallel battery module, etc.

[0093] In some embodiments, there may be one or more heating films, one battery module may correspond to one heating film, and multiple heating films may be connected in series.

[0094] For example, Figure 3 As shown, the electric box loop 20 is connected in parallel with the heating circuit 12. The first electric box 21, the second electric box 22 and the third electric box 23 are connected in series. The first switch element 24 is connected to the total positive electrode 26, and the second switch element 25 is connected to the total negative electrode 27. Each electric box corresponds to a heating film.

[0095] For example, Figure 4As shown, the first electrical box 21 may include a battery module 31, a battery module 32, a battery module 33, and a bar 34 connecting the battery cells. Each battery module may include a plurality of battery cells (e.g., 21, or 23, etc.) arranged in a single row, and the heating film 13 is attached to the side of each battery module and separates the battery cell insulating glue between adjacent battery modules.

[0096] After the switch element is closed, the heating circuit is open, the heating film starts working, and the battery management system can collect electrical signals in the heating circuit.

[0097] In some embodiments, the heating circuit may further include an electrical signal acquisition component to acquire electrical signals in the heating circuit. The electrical signal acquisition component may be one or more, and the electrical signal acquisition component may include but is not limited to at least one of a voltage signal acquisition component, a current signal acquisition component, etc., such as a voltmeter, a current sensor, etc.

[0098] In some embodiments, the electrical signal acquisition component in the heating circuit can be added to the heating circuit.

[0099] For example, the current signal acquisition component can be connected in series to the heating circuit, so as to increase the accuracy of the acquired current signal of the heating circuit.

[0100] For another example, the voltage signal acquisition component can be connected in parallel to the heating circuit, so as to increase the accuracy of the acquired voltage signal of the heating circuit.

[0101] For example, Figure 5 As shown, after the current sensor 28, the heating film, the first switching element 24, the second switching element 25, the total positive electrode 26, and the total negative electrode 27 are connected in series, when the switching element is closed to make the heating film work, the current signal of the heating circuit 12 can be collected through the current sensor 28.

[0102] In some embodiments, when the switch element is closed to operate the heating film, a voltage signal and a current signal in the heating circuit can be collected by a voltmeter and an ammeter, respectively, and a resistance signal can be calculated based on the collected voltage signal and current signal.

[0103] In some embodiments, a current sensor can be connected in series to the total circuit after the electrical box loop and the heating circuit are connected in parallel, and the current signal of the electrical box loop can be collected in advance. Then, based on the current signal of the total circuit collected by the current sensor and the current signal of the electrical box loop, the current signal of the heating circuit can be obtained.

[0104] In some embodiments, the switching element of the heating circuit can be controlled to be turned off based on the current signal of the heating circuit and the resistance signal of the heating circuit obtained according to the current signal and the voltage signal of the heating circuit. In this way, the problem of misjudging the working state of the heating circuit based on a single type of electrical signal, which may cause the heating film to stop working by mistake, can be reduced, and the performance of the battery product can be further improved.

[0105] The sampling time point may be the moment when the electrical signal is collected, and the time interval between each two consecutive sampling time points may be the same or different.

[0106] In some embodiments, the battery management system may periodically collect electrical signals in the heating circuit, for example, the electrical signals in the heating circuit may be collected at set time intervals.

[0107] In some embodiments, the controller can control the switch element to disconnect in response to the electrical signal collected at multiple sampling time points meeting the target signal characteristics, so that the heating film stops working. The target signal characteristics represent that the heating circuit is abnormal. In this way, during the operation of the heating film, it is possible to determine whether the heating circuit is abnormal based on the electrical signal, identify the abnormal state of the heating circuit, and thus automatically stop the heating process of the heating film in a timely manner when the heating circuit is abnormal, reduce the problem of arcing caused by the disconnection of the heating film resistance wire, or reduce the problem of failure of the battery cell insulation glue after arcing, thereby improving the safety of battery products.

[0108] Here, the target signal characteristic is the characteristic condition corresponding to the electrical signal when the heating circuit needs to stop working, which may include but is not limited to at least one of the following: the value of the electrical signal is greater than or equal to the maximum threshold, and / or is less than or equal to the minimum threshold, the change fluctuation of the value of the electrical signal within a set time period exceeds the fluctuation threshold, the value of the electrical signal is greater than or equal to the maximum threshold within a set time period, and / or is less than or equal to the minimum threshold, etc.

[0109] For example, when the current value of the heating circuit exceeds the preset maximum current threshold, the battery management system can determine that the current in the heating circuit has increased abnormally and there is a fault, and control the switch element to disconnect the heating circuit, so that the heating film stops working. In this way, the battery management system can disconnect the heating circuit in time when an abnormal fault occurs in the heating circuit by real-time monitoring of the value of the current signal.

[0110] For another example, the battery management system can periodically obtain the resistance value in the heating circuit and calculate the variance of the resistance value. When the variance of the resistance value exceeds the preset maximum variance threshold for 2 seconds, it is determined that the resistance in the heating circuit fluctuates abnormally and there is a fault, and the switch element is controlled to disconnect the heating circuit, so that the heating film stops working. In this way, the battery management system can disconnect the heating circuit in time when an abnormal fault occurs in the heating circuit by monitoring the fluctuation of the resistance signal.

[0111] For example, Figure 6 As shown, based on the above battery management system, the process from the occurrence of an abnormality in the heating film to the resolution of the abnormality may include the following steps S101 to S104:

[0112] Step S101: The heating film is abnormal.

[0113] Here, the situation where the heating film resistance wire is disconnected can be identified as an abnormal situation, which can include the situation where arcing has occurred or the situation where arcing has not occurred.

[0114] Step S102: The battery management system identifies whether the electrical signal meets the target signal characteristics.

[0115] Step S103: The battery management system responds to the identification result.

[0116] Step S104, turning off the switch element.

[0117] Here, the battery management system may control the switch element in the heating circuit to be disconnected in step S103 in response to the electrical signal identified in step S102 satisfying the target signal characteristic.

[0118] In step S104, after the switching element in the heating circuit is disconnected, the abnormality is resolved and the event is completed.

[0119] It is understandable that steps S101 to S103 may be started after the resistance wire of one side of the heating film is disconnected and arc damage occurs, and completed before the insulation glue of the battery cells corresponding to the heating films on both sides is damaged and the insulation between the battery cells fails. Figure 1 As shown in t 0 Time to t 2 In this way, when the heating film is abnormal, the abnormal state of the heating circuit can be identified in time and the heating process of the heating film can be automatically stopped before the insulation between the battery cells fails, the battery shell breaks down, arcs are drawn between the battery cells, and fire occurs.

[0120] In an embodiment of the present application, in a battery management system, a controller controls each of at least one switch element of a heating circuit to be turned on, so that at least one heating film heats the battery cells in the battery system, that is, the heating film is operated; during the operation of the heating film, the controller collects electrical signals in the heating circuit, and the electrical signals include current signals, and / or current signals and voltage signals of the heating film; based on the electrical signals collected at multiple sampling time points, the controller controls any number of switch elements in at least one switch element of the heating circuit to be turned off, so that the heating film stops heating the battery cells, that is, the heating film stops operating. In this way, since the electrical signals collected at multiple sampling time points can more accurately reflect the operating state of the heating circuit, based on the electrical signals collected at multiple sampling time points, the switching off of the switch elements in the heating circuit can be more accurately and timely controlled to better meet the operating requirements of the heating circuit, so that the heating film can stop heating the battery cells more accurately and timely, thereby improving the safety and performance of the battery product.

[0121] In some embodiments, the controller in the above-mentioned battery management system can also be used to: determine the electrical signal characteristic value corresponding to each time point in the multiple sampling time points based on the electrical signals collected at multiple sampling time points; and control any number of switching elements in at least one switching element to turn off based on the electrical signal characteristic value corresponding to at least one time point, so that the heating film stops heating the battery cell.

[0122] In the embodiment of the present application, the controller determines the characteristic value of the electric signal corresponding to each time point in the multiple sampling time points based on the electric signal collected at the multiple sampling time points; based on the characteristic value of the electric signal corresponding to at least one time point, controls any number of switch elements in at least one switch element of the heating circuit to be turned off, so that the heating film stops heating. In this way, since the electric signals collected at the multiple sampling time points can more accurately reflect the working state of the heating circuit, based on the characteristic value of the electric signal corresponding to at least one time point determined according to the electric signals collected at the multiple sampling time points, the switching element in the heating circuit can be more accurately and timely controlled to be turned off, so as to better meet the working requirements of the heating circuit, so that the heating film can stop heating the battery cell more accurately and timely, thereby improving the safety and performance of the battery product.

[0123] In some embodiments, the electrical signal characteristic value includes a resistance characteristic value, and the controller in the battery management system may also be used to:

[0124] Determine a resistance value corresponding to each time point in a plurality of sampling time points based on the current signal and a voltage signal of at least one heating film;

[0125] For each time point among the plurality of sampling time points, a resistance characteristic value corresponding to the time point is determined based on resistance values ​​corresponding to other time points prior to the time point.

[0126] Here, the resistance characteristic value may be a value used to determine whether a resistance signal in the heating circuit is in an abnormal state. The battery management system may more accurately identify the abnormal state of the heating circuit based on the resistance characteristic value determined based on the resistance value, further improve the detection accuracy of the abnormal state and reduce the misjudgment of the abnormality, so as to further improve the safety and performance of the battery product.

[0127] In some implementations, the resistance value of the heating circuit calculated based on the collected electrical signal may be determined as the resistance characteristic value, or the resistance value may be calculated to obtain the resistance characteristic value.

[0128] For example, the resistance characteristic value may include a real-time resistance value corresponding to a sampling time point.

[0129] For another example, the resistance characteristic value may include an average value of resistance values ​​corresponding to at least two sampling time points prior to the current sampling time point.

[0130] For another example, the resistance characteristic value may include a variance of resistance values ​​corresponding to at least two sampling time points prior to the current sampling time point.

[0131] In some embodiments, after collecting the resistance values ​​corresponding to a target number of sampling time points before the current sampling time point, the average value of the resistance values ​​corresponding to the target number of sampling time points can be calculated; and then based on the calculated average value of the resistance values, the variance of the resistance values ​​corresponding to the target number of sampling time points can be determined.

[0132] Exemplarily, the variance of the resistance values ​​corresponding to the target number of sampling time points is determined s 2 The process is shown in formula (1):

[0133] (1);

[0134] in, N is the target number, X is the resistance value corresponding to the sampling time point, From the current sampling time point forward N The average value of the resistance value corresponding to the sampling time points.

[0135] In some implementations, the absolute value of the resistance value corresponding to the current sampling time point may be determined as the resistance characteristic value corresponding to the current sampling time point, or the resistance characteristic value corresponding to the current sampling time point may be calculated based on the absolute value of the resistance value corresponding to the current sampling time point.

[0136] For example, after collecting the absolute value of the resistance value corresponding to the current sampling time point and the absolute value of the resistance value corresponding to the sampling time point before the current sampling time point, the average value of the absolute values ​​of the two collected resistance values ​​can be calculated, and the average value can be determined as the resistance characteristic value corresponding to the current sampling time point.

[0137] In some embodiments, when the resistance characteristic value is the absolute value of the resistance value corresponding to the current sampling time point, after collecting the voltage signal of the heating film and the current signal in the heating circuit, the absolute value of the resistance value in the heating circuit can be calculated based on the voltage signal and the current signal.

[0138] For example, the process of determining the absolute value of the resistance value in the heating circuit is as follows:

[0139] (2);

[0140] in, is the absolute value of the resistance, is the absolute value of the voltage, is the absolute value of the current.

[0141] In the embodiment of the present application, the controller determines the resistance value corresponding to each time point in multiple sampling time points based on the current signal and the voltage signal of the heating film; and determines the resistance characteristic value corresponding to each time point based on the resistance values ​​corresponding to other time points before each time point. In this way, since the resistance signal in the heating circuit is usually relatively stable and not easily affected by temperature, battery charging process, etc., during the operation of the heating film, the resistance characteristic value determined based on the resistance value can more accurately reflect the working state of the heating circuit, thereby further improving the accuracy and timeliness of shutting down the switch element in the heating circuit, so as to further improve the safety and performance of the battery product.

[0142] In some embodiments, the controller in the battery management system may also be used to:

[0143] In response to a resistance characteristic value corresponding to any time point among a plurality of sampling time points being greater than or equal to a first resistance threshold, any number of switch elements in at least one switch element are controlled to be turned off.

[0144] Here, the first resistance threshold may be a maximum resistance threshold corresponding to the resistance characteristic value when the heating circuit is in a normal working state, and different resistance characteristic values ​​may correspond to different first resistance thresholds.

[0145] In some embodiments, the battery management system can control the switch element to disconnect in response to the resistance characteristic value corresponding to any time point in multiple sampling time points being greater than or equal to the first resistance threshold value, so as to stop the heating film from working. In this way, the battery management system can automatically identify the abnormal state of the heating circuit and stop the heating film from working based on the magnitude relationship between the resistance characteristic value and the first resistance threshold value, thereby improving the safety of the battery product.

[0146] For example, the resistance characteristic value corresponding to the current sampling time point is the absolute value of the resistance value at the current sampling time point. When the absolute value is greater than a preset maximum resistance threshold, any number of switch elements in at least one switch element can be controlled to be turned off.

[0147] For another example, the resistance characteristic value corresponding to the current sampling time point is the variance of the resistance values ​​at the five sampling time points before the current sampling time point. When the variance is greater than a preset maximum variance threshold, any number of switch elements in at least one switch element can be controlled to be turned off.

[0148] It can be understood that the variance of the resistance value corresponding to the sampling time point and the absolute value of the resistance value can be used together as the resistance characteristic value corresponding to the sampling time point. In this case, the first resistance threshold can include the maximum threshold of the resistance value variance and the maximum threshold of the resistance value absolute value.

[0149] In the embodiment of the present application, the controller controls any number of switch elements in at least one switch element to turn off when the resistance characteristic value corresponding to any time point in the multiple sampling time points is greater than or equal to the first resistance threshold. In this way, the battery management system can more accurately identify the working state of the heating circuit based on the magnitude relationship between the resistance characteristic value and the first resistance threshold, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0150] In some embodiments, the controller in the battery management system may also be used to:

[0151] In response to the number of time points at which the resistance characteristic value is greater than or equal to the second resistance threshold being greater than or equal to the first number threshold, any number of the at least one switching element is controlled to be turned off.

[0152] Here, the second resistance threshold may be a maximum resistance threshold corresponding to the resistance characteristic value when the heating circuit is in a normal working state, and different resistance characteristic values ​​may correspond to different second resistance thresholds.

[0153] The first quantity threshold may be a minimum threshold of the number of sampling time points that characterize the abnormal working state of the heating circuit. The battery management system may more accurately identify the abnormal state of the heating circuit based on the size relationship between the number of sampling time points that characterize the abnormal working state of the heating circuit and the set minimum quantity threshold, thereby further improving the accuracy and timeliness of shutting down the switch element in the heating circuit.

[0154] In some embodiments, the time points at which the characteristic resistance value is greater than or equal to the second resistance threshold value may be continuous sampling time points or discontinuous sampling time points.

[0155] For example, when the resistance characteristic value corresponding to the current sampling time point exceeds the second resistance threshold, and the resistance characteristic values ​​corresponding to three consecutive sampling time points before the current sampling time point also exceed the second resistance threshold, any number of switch elements in at least one switch element can be controlled to be turned off.

[0156] For another example, when the resistance characteristic value corresponding to the current sampling time point exceeds the second resistance threshold, and there are three sampling time points before the current sampling time point whose corresponding resistance characteristic values ​​also exceed the second resistance threshold, any number of switch elements in at least one switch element can be controlled to be turned off.

[0157] In the embodiment of the present application, the controller controls any number of switch elements in at least one switch element to turn off when the number of time points at which the characteristic resistance value is greater than or equal to the second resistance threshold value is greater than or equal to the first number threshold value. In this way, since the resistance values ​​collected at different times have normal fluctuations, and considering that the characteristic resistance value obtained based on the resistance value has normal fluctuations, the working state of the heating circuit can be more accurately identified according to the size relationship between the number of time points at which the characteristic resistance value is greater than or equal to the second resistance threshold value and the first number threshold value, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0158] In some embodiments, the controller in the battery management system may also be used to:

[0159] In response to the number of time points when the resistance characteristic value is greater than or equal to the third resistance threshold being greater than or equal to a second number threshold, and the time points when the resistance characteristic value is greater than or equal to the third resistance threshold being within a first time length, any number of switch elements in at least one switch element are controlled to be turned off.

[0160] Here, the third resistance threshold may be a maximum resistance threshold corresponding to the resistance characteristic value when the heating circuit is in a normal working state, and different resistance characteristic values ​​may correspond to different third resistance thresholds.

[0161] The second quantity threshold may be a minimum threshold of the number of sampling time points that characterize an abnormal working state of the heating circuit.

[0162] The first duration may be a duration that includes at least two sampling time points.

[0163] In some embodiments, when the resistance characteristic value is greater than or equal to the third resistance threshold and the number of times it occurs within the first time period is greater than or equal to the second quantity threshold, it can be determined that the working state of the heating circuit is an abnormal state, and the switching element is further controlled to be turned off, so that the heating film stops working, so as to improve the safety of the battery product.

[0164] In the embodiment of the present application, the controller controls any number of switch elements in at least one switch element to turn off when the number of time points at which the characteristic resistance value is greater than or equal to the third resistance threshold is greater than or equal to the second number threshold, and the time points at which the characteristic resistance value is greater than or equal to the third resistance threshold are within the first time length. In this way, based on the size relationship between the number of time points at which the characteristic resistance value is greater than or equal to the third resistance threshold within the set time length and the second number threshold, the working state of the heating circuit can be more accurately identified, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0165] In some embodiments, the electrical signal characteristic value includes a current characteristic value, and the controller can also be used to: for each time point among multiple sampling time points, determine the current characteristic value corresponding to the time point based on the current values ​​corresponding to other time points before the time point.

[0166] Here, the current characteristic value may be a value used to determine whether a current signal in the heating circuit is in an abnormal state.

[0167] In some embodiments, the battery management system may collect the current value in the heating circuit through a current collection component, and the current collection component may include but is not limited to at least one of an analog ammeter, a digital ammeter, and the like.

[0168] In some implementations, the value of the collected current signal in the heating circuit may be determined as the current characteristic value, or the value of the collected current signal in the heating circuit may be calculated to obtain the current characteristic value.

[0169] For example, the current characteristic value may include a current value corresponding to a sampling time point.

[0170] For another example, the current characteristic value may include an average value of current values ​​corresponding to at least two sampling time points prior to the current sampling time point.

[0171] For another example, the current characteristic value may include a variance of current values ​​corresponding to at least two sampling time points prior to the current sampling time point.

[0172] In the embodiment of the present application, the controller determines the current characteristic value corresponding to each time point based on the current values ​​corresponding to other time points prior to each time point in the multiple sampling time points. In this way, since the heating film gradually ages during use, and the current signal is less affected by the aging of the heating film, during the operation of the heating film, the current characteristic value determined based on the current value can more accurately reflect the working state of the heating circuit, thereby further improving the accuracy and timeliness of shutting off the switch element in the heating circuit, so as to further improve the safety and performance of the battery product.

[0173] In some embodiments, the controller may also be used to: determine the variance between current values ​​corresponding to multiple other time points prior to each time point in the multiple sampling time points as the current characteristic value corresponding to the time point.

[0174] Here, the time point may be the moment when the current signal is collected, may be a continuous time point, or may be a discontinuous time point, and the time interval between every two continuous time points may be the same or different.

[0175] In some embodiments, after collecting current values ​​corresponding to a target number of sampling time points before the current sampling time point, the average value of the current values ​​corresponding to the target number of sampling time points can be calculated; and then based on the calculated average value of the current values, the variance of the current values ​​corresponding to the target number of sampling time points can be determined.

[0176] Exemplarily, the variance of the current values ​​corresponding to the target number of sampling time points is determined r 2 The process can be seen in formula (3):

[0177] (3);

[0178] in, M is the target number, Y is the current value corresponding to the sampling time point, From the current sampling time point forward M The average value of the current value corresponding to the sampling time points.

[0179] In the embodiment of the present application, the controller determines the current characteristic value corresponding to each time point based on the variance between the current values ​​corresponding to multiple other time points prior to each time point in the multiple sampling time points. In this way, considering the influence of normal fluctuations in the current value during the operation of the heating film, the current characteristic value determined by the variance of the current value can more accurately reflect the working state of the heating circuit, thereby further improving the accuracy and timeliness of shutting down the switch element in the heating circuit, so as to further improve the safety and performance of the battery product.

[0180] In some embodiments, the controller may also be configured to: in response to a current characteristic value corresponding to any time point among a plurality of sampling time points being greater than or equal to a first variance threshold, control any number of switch elements in at least one switch element to turn off.

[0181] Here, the first variance threshold may be a maximum threshold of the variance of the current value when the heating circuit is operating normally.

[0182] In some embodiments, the battery management system may control the switch element to be disconnected in response to the current characteristic value corresponding to any time point among the plurality of sampling time points being greater than or equal to the first variance threshold, so as to stop the heating film from working.

[0183] In the embodiment of the present application, the controller controls any number of switch elements in at least one switch element to turn off when the current characteristic value corresponding to any time point in multiple sampling time points is greater than or equal to the first variance threshold. In this way, the battery management system can more accurately identify the working state of the heating circuit based on the magnitude relationship between the current characteristic value and the first variance threshold, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0184] In some embodiments, the controller may also be configured to: in response to the number of time points at which the current characteristic value is greater than or equal to the second variance threshold being greater than or equal to a third number threshold, control any number of the at least one switching element to turn off.

[0185] Here, the second variance threshold may be a maximum variance threshold corresponding to the current characteristic value when the heating circuit is operating normally.

[0186] The third quantity threshold may be a minimum threshold of the number of sampling time points that characterize an abnormal working state of the heating circuit.

[0187] In some implementations, the time points at which the current characteristic value is greater than or equal to the second variance threshold may be continuous sampling time points or discontinuous sampling time points.

[0188] In the above embodiment, the controller controls any number of switch elements in at least one switch element to turn off when the number of time points at which the current characteristic value is greater than or equal to the second variance threshold is greater than or equal to the third number threshold. In this way, since the current values ​​collected at different times have normal fluctuations, and considering that the current characteristic value obtained based on the current value has normal fluctuations, the working state of the heating circuit can be more accurately identified based on the relationship between the number of time points at which the current characteristic value is greater than or equal to the second variance threshold and the third number threshold, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0189] In some embodiments, the controller can also be used to: in response to the number of time points when the current characteristic value is greater than or equal to the third difference threshold being greater than or equal to a fourth quantity threshold, and the time points when the current characteristic value is greater than or equal to the third difference threshold being within the second time length, control any number of switch elements in at least one switch element to turn off.

[0190] Here, the third variance threshold may be a maximum variance threshold corresponding to the current characteristic value when the heating circuit is operating normally.

[0191] The fourth quantity threshold may be a minimum threshold of the number of sampling time points that characterize an abnormal working state of the heating circuit.

[0192] The second duration may be a duration that includes at least two sampling time points.

[0193] In some implementations, the time points at which the current characteristic value is greater than or equal to the third difference threshold may be continuous sampling time points or discontinuous sampling time points.

[0194] For example, a current signal is collected every 0.1 seconds. When the current characteristic value corresponding to the current sampling time point exceeds the third difference threshold, and the current characteristic values ​​corresponding to three consecutive sampling time points within 0.5 seconds before the current sampling time point also exceed the third difference threshold, any number of switch elements in at least one switch element can be controlled to be turned off.

[0195] In some embodiments, when the current characteristic value is greater than or equal to the third difference threshold and the number of times it occurs within the second time period is greater than or equal to the fourth quantity threshold, it can be determined that the working state of the heating circuit is abnormal, and the switching element is further controlled to be turned off, so that the heating film stops working, so as to improve the safety of the battery product.

[0196] In the embodiment of the present application, the controller controls any number of switch elements in at least one switch element to turn off when the number of time points at which the current characteristic value is greater than or equal to the third difference threshold is greater than or equal to the fourth number threshold, and the time points at which the current characteristic value is greater than or equal to the third difference threshold are within the first time period. In this way, based on the size relationship between the number of time points at which the current characteristic value is greater than or equal to the third difference threshold within the set time period and the fourth number threshold, the working state of the heating circuit can be more accurately identified, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0197] In some embodiments, the characteristic value of the electrical signal includes the absolute value of the current value, and the controller can also be used to: in response to the absolute value of the current value corresponding to any time point in multiple sampling time points being less than or equal to the first current threshold, control any number of switch elements in at least one switch element to turn off.

[0198] Here, the first current threshold may be a minimum current threshold corresponding to the absolute value of the current value when the heating circuit is operating normally.

[0199] In some implementations, the absolute value of the current value corresponding to the current sampling time point may be determined as the current characteristic value corresponding to the current sampling time point, or the current characteristic value corresponding to the current sampling time point may be calculated based on the absolute value of the current value corresponding to the current sampling time point.

[0200] For example, after collecting the absolute value of the current value corresponding to the current sampling time point and the absolute value of the current value corresponding to the sampling time point before the current sampling time point, the average value of the absolute values ​​of the two collected current values ​​can be calculated, and the average value can be determined as the current characteristic value corresponding to the current sampling time point.

[0201] For example, the process of determining the absolute value of the current value corresponding to the current sampling time point is as follows:

[0202] (4);

[0203] in, C is the absolute value of the current corresponding to the current sampling time point, I is the current value corresponding to the current sampling time point.

[0204] In the above embodiment, when the absolute value of the current value corresponding to any time point in multiple sampling time points is less than or equal to the first current threshold, the controller controls any number of switch elements in at least one switch element to turn off. In this way, the battery management system can more accurately identify the working state of the heating circuit based on the relationship between the absolute value of the current value and the first current threshold, thereby further improving the accuracy of turning off the switch elements in the heating circuit; on the other hand, since the calculation process of obtaining the absolute value of the current value corresponding to the sampling time point is simple, identifying the working state of the heating circuit based on the absolute value of the current value corresponding to the sampling time point can improve the timeliness of turning off the switch elements in the heating circuit, further improving the safety and performance of the battery product.

[0205] In some embodiments, the characteristic value of the electrical signal includes the absolute value of the current value, and the controller can also be used to: in response to the number of time points when the absolute value of the current value is less than or equal to the second current threshold being greater than or equal to a fifth quantity threshold, control any number of switching elements in at least one switching element to turn off.

[0206] Here, the second current threshold may be a minimum current threshold corresponding to the absolute value of the current value when the heating circuit is operating normally.

[0207] The fifth quantity threshold may be a minimum threshold of the number of sampling time points that characterize an abnormal working state of the heating circuit.

[0208] In the embodiment of the present application, the controller controls any number of switch elements in at least one switch element to be turned off when the number of time points at which the absolute value of the current value is less than or equal to the second current threshold is greater than or equal to the fifth number threshold. In this way, since the current values ​​collected at different times have normal fluctuations, and considering that the absolute value of the current value obtained based on the current value has normal fluctuations, the working state of the heating circuit can be more accurately identified according to the size relationship between the number of time points at which the absolute value of the current value is less than or equal to the second current threshold and the number of time points at which the absolute value of the current value is less than or equal to the second current threshold is greater than or equal to the fifth number threshold, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0209] In some embodiments, the characteristic value of the electrical signal includes the absolute value of the current value, and the controller can also be used to: in response to the number of time points when the absolute value of the current value is less than or equal to the third current threshold being greater than or equal to a sixth number threshold, and the time points when the absolute value of the current value is less than or equal to the third current threshold being within a third time length, control any number of switching elements in at least one switching element to turn off.

[0210] Here, the third current threshold may be a minimum current threshold corresponding to the absolute value of the current value when the heating circuit is operating normally.

[0211] The fifth quantity threshold may be a minimum threshold of the number of sampling time points that characterize an abnormal working state of the heating circuit.

[0212] The third duration may be a duration that includes at least two sampling time points.

[0213] In some implementations, the time points at which the absolute value of the current value is less than or equal to the third current threshold value may be continuous sampling time points or discontinuous sampling time points.

[0214] For example, a current signal is collected every 0.1 seconds. When the absolute value of the current value corresponding to the current sampling time point exceeds the third current threshold, and the absolute values ​​of the current values ​​corresponding to four sampling time points within 0.4 seconds before the current sampling time point also exceed the third current threshold, any number of switching elements in at least one switching element can be controlled to be turned off.

[0215] In some embodiments, when the absolute value of the current value is less than or equal to the third current threshold and the number of times it occurs within the third time period is greater than or equal to the sixth quantity threshold, it can be determined that the working state of the heating circuit is an abnormal state, and the switching element is further controlled to be turned off, so that the heating film stops working, so as to improve the safety of the battery product.

[0216] In the embodiment of the present application, the controller controls any number of switch elements in at least one switch element to be turned off when the number of time points at which the absolute value of the current value is less than or equal to the third current threshold is greater than or equal to the sixth number threshold, and the time points at which the absolute value of the current value is less than or equal to the third current threshold is within the third time period. In this way, based on the size relationship between the number of time points at which the absolute value of the current value is less than or equal to the third current threshold within the set time period and the sixth number threshold, the working state of the heating circuit can be more accurately identified, thereby further improving the accuracy and timeliness of turning off the switch elements in the heating circuit, so as to further improve the safety and performance of the battery product.

[0217] In some embodiments, the characteristic value of the electrical signal includes a resistance characteristic value and a current characteristic value, and the controller can also be used to: determine the resistance value corresponding to each time point in a plurality of sampling time points based on the current signal and the voltage signal of at least one heating film; for each time point in a plurality of sampling time points, determine the resistance characteristic value corresponding to the time point based on the resistance values ​​corresponding to other time points prior to the time point; for each time point in a plurality of sampling time points, determine the current characteristic value corresponding to the time point based on the current values ​​corresponding to other time points prior to the time point.

[0218] In the embodiment of the present application, the controller determines the resistance characteristic value and the current characteristic value corresponding to each time point in multiple sampling time points based on the current signal and the voltage signal of at least one heating film. In this way, the working state of the heating current is identified based on at least two characteristic values, which is not easily affected by the inaccurate identification caused by the abnormality of a single characteristic value, and can further improve the accuracy and timeliness of shutting down the switch element in the heating circuit, so as to further improve the safety and performance of the battery product.

[0219] In some embodiments, the controller may also be used to: determine the variance between the current values ​​corresponding to multiple other time points prior to each time point in the multiple sampling time points as the current characteristic value corresponding to the time point; in response to the resistance characteristic value corresponding to at least one time point in the multiple sampling time points satisfying the first characteristic condition, and the current characteristic value corresponding to at least one time point in the multiple sampling time points satisfying the second characteristic condition, control any number of switch elements in the at least one switch element to turn off;

[0220] The first characteristic condition includes one of the following:

[0221] The resistance characteristic value corresponding to any time point among the multiple sampling time points is greater than or equal to the fourth resistance threshold;

[0222] The number of time points at which the resistance characteristic value is greater than or equal to the fifth resistance threshold is greater than or equal to a seventh number threshold;

[0223] The number of time points at which the characteristic resistance value is greater than or equal to the sixth resistance threshold is greater than or equal to an eighth number threshold, and the time points at which the characteristic resistance value is greater than or equal to the sixth resistance threshold are within a fourth time duration;

[0224] The second characteristic condition includes one of the following:

[0225] The current characteristic value corresponding to any time point among the multiple sampling time points is greater than or equal to the fourth variance threshold;

[0226] The number of time points at which the current characteristic value is greater than or equal to the fifth variance threshold is greater than or equal to a ninth number threshold;

[0227] The number of time points at which the current characteristic value is greater than or equal to the sixth variance threshold is greater than or equal to the tenth number threshold, and the time points at which the current characteristic value is greater than or equal to the sixth variance threshold are within the fifth time length.

[0228] Here, the first characteristic condition may be a characteristic condition characterizing abnormal resistance in the heating circuit, and the second characteristic condition may be a characteristic condition characterizing abnormal current in the heating circuit.

[0229] In some embodiments, the fourth resistance threshold, the fifth resistance threshold, and the sixth resistance threshold may be the maximum resistance thresholds corresponding to the resistance characteristic values ​​when the heating circuit is working normally, and different resistance characteristic values ​​may correspond to different fourth resistance thresholds, fifth resistance thresholds, and sixth resistance thresholds.

[0230] In some embodiments, the seventh quantity threshold, the eighth quantity threshold, the ninth quantity threshold, and the tenth quantity threshold may be minimum thresholds for the number of sampling time points that characterize an abnormal working state of the heating circuit.

[0231] In some implementations, the fourth duration and the fifth duration may be continuous durations including at least two sampling time points.

[0232] In some implementations, the fourth variance threshold, the fifth variance threshold, and the sixth variance threshold may be maximum thresholds of the variance of the current value when the heating circuit is operating normally.

[0233] In implementation, the first variance threshold, the second variance threshold, the third variance threshold, the fourth variance threshold, the fifth variance threshold, and the sixth variance threshold may be the same or different.

[0234] In an embodiment of the present application, the controller determines a current characteristic value based on the variance between current values ​​corresponding to multiple other time points prior to any time point among multiple sampling time points; when the resistance characteristic value at any time point among the multiple sampling time points satisfies the first characteristic condition, and the current characteristic value corresponding to the time point satisfies the second characteristic condition, any number of switch elements in at least one switch element are controlled to be turned off; the first characteristic condition includes that the resistance characteristic value corresponding to the time point satisfies the numerical condition, the number of sampling time points at which the resistance characteristic value satisfies the numerical condition satisfies the quantity condition, the number of sampling time points at which the resistance characteristic value satisfies the numerical condition satisfies the quantity condition, and the collection time length for collecting the sampling time points that meet the quantity condition satisfies the time length condition; the second characteristic condition includes that the current characteristic value corresponding to the time point satisfies the numerical condition, the number of sampling time points at which the current characteristic value satisfies the numerical condition satisfies the quantity condition, the number of sampling time points at which the current characteristic value satisfies the numerical condition satisfies the quantity condition, and the collection time length for collecting the sampling time points that meet the quantity condition satisfies the time length condition. In this way, the battery management system can more accurately identify the working state of the heating circuit based on the size relationship between the resistance characteristic value and the corresponding characteristic value threshold, the current value variance and the variance threshold, the number of sampling time points at which the characteristic value and the corresponding characteristic value threshold satisfy the size relationship, and the duration between the sampling time points at which the characteristic value and the corresponding characteristic value threshold satisfy the size relationship, thereby further improving the accuracy and timeliness of shutting off the switching element in the heating circuit; on the other hand, combined with the variance of the current value, the influence of normal fluctuations of the current value on the judgment of the working state of the heating circuit can be reduced, thereby further improving the accuracy of shutting off the switching element in the heating circuit, so as to further improve the safety and performance of the battery product.

[0235] In some embodiments, the current characteristic value includes an absolute value of the current value, and the controller may further be used to: in response to the resistance characteristic value corresponding to at least one time point in the multiple sampling time points satisfying a third characteristic condition, and the absolute value of the current value corresponding to at least one time point in the multiple sampling time points satisfying a fourth characteristic condition, control any number of switch elements in the at least one switch element to turn off;

[0236] The third characteristic condition includes one of the following:

[0237] The resistance characteristic value corresponding to any time point among the multiple sampling time points is greater than or equal to the seventh resistance threshold;

[0238] The number of time points at which the resistance characteristic value is greater than or equal to the eighth resistance threshold value is greater than or equal to the eleventh number threshold value;

[0239] The number of time points at which the resistance characteristic value is greater than or equal to the ninth resistance threshold value is greater than or equal to the twelfth number threshold value, and the time points at which the resistance characteristic value is greater than or equal to the ninth resistance threshold value are within the sixth time length;

[0240] The fourth characteristic condition includes one of the following:

[0241] The absolute value of the current value corresponding to any time point among the multiple sampling time points is less than or equal to the fourth current threshold;

[0242] The number of time points at which the absolute value of the current value is less than or equal to the fifth current threshold is greater than or equal to the thirteenth number threshold;

[0243] The number of time points at which the absolute value of the current value is less than or equal to the sixth current threshold is greater than or equal to the fourteenth number threshold, and the time points at which the absolute value of the current value is less than or equal to the sixth current threshold are within the seventh time length.

[0244] Here, the third characteristic condition may be a characteristic condition characterizing abnormal resistance in the heating circuit, and the fourth characteristic condition may be a characteristic condition characterizing abnormal current in the heating circuit.

[0245] In some embodiments, the seventh resistance threshold, the eighth resistance threshold, and the ninth resistance threshold may be the maximum resistance thresholds corresponding to the resistance characteristic values ​​when the heating circuit is working normally, and different resistance characteristic values ​​may correspond to different seventh resistance thresholds, eighth resistance thresholds, and ninth resistance thresholds.

[0246] In implementation, the first resistance threshold, the second resistance threshold, the third resistance threshold, the fourth resistance threshold, the fifth resistance threshold, the sixth resistance threshold, the seventh resistance threshold, the eighth resistance threshold, and the ninth resistance threshold may be the same or different.

[0247] In some embodiments, the fourth current threshold, the fifth current threshold, and the sixth current threshold may be minimum current thresholds corresponding to the absolute values ​​of the current values ​​when the heating circuit is operating normally.

[0248] In implementation, the first current threshold, the second current threshold, the third current threshold, the fourth current threshold, the fifth current threshold, and the sixth current threshold may be the same or different.

[0249] In some embodiments, the eleventh quantity threshold, the twelfth quantity threshold, the thirteenth quantity threshold, and the fourteenth quantity threshold may be minimum thresholds for the number of sampling time points that characterize an abnormal working state of the heating circuit.

[0250] In implementation, the first quantity threshold, the second quantity threshold, the third quantity threshold, the fourth quantity threshold, the fifth quantity threshold, the sixth quantity threshold, the seventh quantity threshold, the eighth quantity threshold, the ninth quantity threshold, the tenth quantity threshold, the eleventh quantity threshold, the twelfth quantity threshold, the thirteenth quantity threshold, and the fourteenth quantity threshold may be the same or different.

[0251] In some implementations, the sixth duration and the seventh duration may be continuous durations including at least two sampling time points.

[0252] In implementation, the first duration, the second duration, the third duration, the fourth duration, the fifth duration, the sixth duration, and the seventh duration may be the same or different.

[0253] In an embodiment of the present application, when the resistance characteristic value corresponding to at least one time point among multiple sampling time points satisfies the third characteristic condition, and the absolute value of the current value corresponding to the time point satisfies the fourth characteristic condition, any number of switch elements in at least one switch element are controlled to be turned off; the third characteristic condition includes that the resistance characteristic value corresponding to the time point satisfies the numerical condition, the number of sampling time points at which the resistance characteristic value satisfies the numerical condition satisfies the quantity condition, the number of sampling time points at which the resistance characteristic value satisfies the numerical condition satisfies the quantity condition, and the collection time length for collecting the sampling time points that meet the quantity condition satisfies the time length condition; the fourth characteristic condition includes that the absolute value of the current value corresponding to the time point satisfies the numerical condition, the number of sampling time points at which the absolute value of the current value satisfies the numerical condition satisfies the quantity condition, the number of sampling time points at which the absolute value of the current value satisfies the numerical condition satisfies the quantity condition, and the collection time length for collecting the sampling time points that meet the quantity condition satisfies the time length condition. In this way, the battery management system can more accurately identify the working state of the heating circuit based on the relationship between the resistance characteristic value and the corresponding characteristic value threshold, the absolute value of the current value and the current threshold, the number of sampling time points at which the characteristic value and the corresponding characteristic value threshold satisfy the relationship, and the duration between the sampling time points at which the characteristic value and the corresponding characteristic value threshold satisfy the relationship, thereby further improving the accuracy and timeliness of shutting down the switching element in the heating circuit; on the other hand, since the calculation process of obtaining the absolute value of the current value corresponding to the sampling time point is relatively simple, identifying the working state of the heating circuit based on the absolute value of the current value corresponding to the sampling time point can further improve the timeliness of shutting down the switching element in the heating circuit, thereby further improving the safety and performance of the battery product.

[0254] In some embodiments, the heating film is disposed on the surface of at least one group of battery cells, and an insulating protective layer is disposed between the heating film and the surface of the battery cells.

[0255] Here, an insulating protective material may be added between the heating film and the surface of the battery core. The insulating protective material may include but is not limited to at least one of a composite tape composed of two or more metal materials, mica paper, mica board, Teflon, etc.

[0256] In some embodiments, an insulating protective material may be added between the surface of the battery cell and the aluminum shell of the battery cell.

[0257] By providing an insulating protective layer between the heating film and the surface of the battery cell, the time from when the resistance wire of the heating film on one side is disconnected and arc damage occurs to when the heating film on that side and the heating film on the opposite side arc damage occurs can be extended, thereby damaging the battery cell insulation glue corresponding to the heating films on both sides, causing insulation failure between the battery cells, battery cell shell breakdown, arcing between the battery cells, fire and other problems, thereby providing the battery management system with more recognition and response time. For example, the time from when the resistance wire of the heating film on one side is disconnected and arc damage occurs can be extended. Figure 1 middle t 0 Time has come t 2 Duration of the moment

[0258] In the embodiment of the present application, an insulating protective layer is provided between the heating film and the surface of the battery cell. In this way, on the one hand, the insulation safety of the battery product can be improved; on the other hand, the time when the insulation failure between the battery cells caused by the damage of the heating film can be prolonged, thereby prolonging the time to identify the working state of the heating circuit before the insulation failure between the battery cells, and more accurately and timely controlling the shutdown of the switch element in the heating circuit to better meet the working requirements of the heating circuit, so that the heating film can stop heating the battery cell more accurately and timely, thereby improving the safety and performance of the battery product.

[0259] The present application embodiment provides a control method for a heating circuit, which can be applied to the above-mentioned battery management system. Figure 7 As shown, the control method of the heating circuit includes the following steps S201 to S203:

[0260] Step S201: Control each switch element in at least one switch element to be turned on so that a heating film heats a battery cell in a battery system.

[0261] Step S202: In the process of the heating film heating the battery cells in the battery system, an electrical signal in the heating circuit is collected; the electrical signal includes a current signal, and / or a current signal and a voltage signal of at least one heating film.

[0262] Step S203: Based on the electrical signals collected at multiple sampling time points, any number of switch elements in at least one switch element are controlled to be turned off, so that the heating film stops heating the battery cell.

[0263] In some embodiments, the above step S203 may include the following steps S231 to S232:

[0264] Step S231: Based on the electrical signals collected at multiple sampling time points, determine the electrical signal characteristic value corresponding to each time point in the multiple sampling time points.

[0265] Step S232: Based on the characteristic values ​​of the electrical signal corresponding to at least one time point, any number of the switch elements in the at least one switch element are controlled to be turned off, so that the heating film stops heating the battery cell.

[0266] In some implementations, steps S201 to S203 in the above-mentioned method for controlling the heating circuit may be completed by a controller in the above-mentioned battery management system.

[0267] In some embodiments, the electrical signal characteristic value includes a resistance characteristic value, and the above step S231 may include the following steps S301 to S302:

[0268] Step S301: determining a resistance value corresponding to each time point in a plurality of sampling time points based on a current signal and a voltage signal of at least one heating film.

[0269] Step S302: for each time point among the plurality of sampling time points, determine a resistance characteristic value corresponding to the time point based on resistance values ​​corresponding to other time points prior to the time point.

[0270] In some embodiments, the above step S232 may include the following steps S401:

[0271] Step S401 : in response to a resistance characteristic value corresponding to any time point among a plurality of sampling time points being greater than or equal to a first resistance threshold, controlling any number of switch elements in at least one switch element to be turned off.

[0272] In some embodiments, the above step S232 may include the following steps S501:

[0273] Step S501 : in response to the number of time points at which the resistance characteristic value is greater than or equal to the second resistance threshold being greater than or equal to a first number threshold, controlling any number of switch elements in at least one switch element to be turned off.

[0274] In some embodiments, the above step S232 may include the following steps S601:

[0275] Step S601, in response to the number of time points at which the resistance characteristic value is greater than or equal to the third resistance threshold being greater than or equal to a second number threshold, and the time points at which the resistance characteristic value is greater than or equal to the third resistance threshold being within a first time period, controlling any number of switch elements in at least one switch element to be turned off.

[0276] In some embodiments, the electrical signal characteristic value includes a current characteristic value, and the above step S231 may include the following steps S701:

[0277] Step S701: for each time point among a plurality of sampling time points, determine a current characteristic value corresponding to the time point based on current values ​​corresponding to other time points prior to the time point.

[0278] In some embodiments, the above step S701 may include the following step S801:

[0279] Step S801: Determine the variance between current values ​​corresponding to a plurality of other time points prior to each time point among a plurality of sampling time points as the current characteristic value corresponding to the time point.

[0280] In some embodiments, the above step S232 may include the following steps S901:

[0281] Step S901 : in response to a current characteristic value corresponding to any time point among a plurality of sampling time points being greater than or equal to a first variance threshold, controlling any number of switch elements among at least one switch element to be turned off.

[0282] In some embodiments, the above step S232 may include the following steps S1001:

[0283] Step S1001 : in response to the number of time points at which the current characteristic value is greater than or equal to the second variance threshold being greater than or equal to a third number threshold, controlling any number of switch elements in at least one switch element to be turned off.

[0284] In some embodiments, the above step S232 may include the following steps S1101:

[0285] Step S1101, in response to the number of time points when the current characteristic value is greater than or equal to the third difference threshold being greater than or equal to a fourth quantity threshold, and the time points when the current characteristic value is greater than or equal to the third difference threshold being within a second time period, controlling any number of switch elements in at least one switch element to turn off.

[0286] In some embodiments, the electrical signal characteristic value includes an absolute value of a current value, and the above step S232 may include the following steps S1201:

[0287] Step S1201 : in response to an absolute value of a current value corresponding to any time point among a plurality of sampling time points being less than or equal to a first current threshold, controlling any number of switch elements in at least one switch element to be turned off.

[0288] In some embodiments, the electrical signal characteristic value includes an absolute value of a current value, and the above step S232 may include the following steps S1301:

[0289] Step S1301 : in response to the number of time points at which the absolute value of the current value is less than or equal to the second current threshold being greater than or equal to a fifth number threshold, controlling any number of switch elements in at least one switch element to be turned off.

[0290] In some embodiments, the electrical signal characteristic value includes an absolute value of a current value, and the above step S232 may include the following steps S1401:

[0291] Step S1401, in response to the number of time points when the absolute value of the current value is less than or equal to the third current threshold being greater than or equal to a sixth number threshold, and the time points when the absolute value of the current value is less than or equal to the third current threshold being within a third time period, controlling any number of switch elements in at least one switch element to turn off.

[0292] In some embodiments, the electrical signal characteristic value includes a resistance characteristic value and a current characteristic value, and the above step S231 may include the following steps S1501 to S1503:

[0293] Step S1501: determining a resistance value corresponding to each time point in a plurality of sampling time points based on a current signal and a voltage signal of at least one heating film.

[0294] Step S1502: for each time point among the plurality of sampling time points, determine a resistance characteristic value corresponding to the time point based on resistance values ​​corresponding to other time points prior to the time point.

[0295] Step S1503: for each time point among the multiple sampling time points, determine the current characteristic value corresponding to the time point based on the current values ​​corresponding to other time points prior to the time point.

[0296] In some embodiments, the above step S232 may include the following steps S1601 to S1602:

[0297] Step S1601: Determine the current characteristic value corresponding to a time point by taking the variance between the current values ​​corresponding to a plurality of other time points prior to each time point in a plurality of sampling time points.

[0298] Step S1602: in response to a resistance characteristic value corresponding to at least one time point among the multiple sampling time points satisfying a first characteristic condition, and a current characteristic value corresponding to at least one time point among the multiple sampling time points satisfying a second characteristic condition, controlling any number of switch elements among the at least one switch element to be turned off;

[0299] The first characteristic condition includes one of the following:

[0300] The resistance characteristic value corresponding to any time point among the multiple sampling time points is greater than or equal to the fourth resistance threshold;

[0301] The number of time points at which the resistance characteristic value is greater than or equal to the fifth resistance threshold is greater than or equal to a seventh number threshold;

[0302] The number of time points at which the characteristic resistance value is greater than or equal to the sixth resistance threshold is greater than or equal to an eighth number threshold, and the time points at which the characteristic resistance value is greater than or equal to the sixth resistance threshold are within a fourth time duration;

[0303] The second characteristic condition includes one of the following:

[0304] The current characteristic value corresponding to any time point among the multiple sampling time points is greater than or equal to the fourth variance threshold;

[0305] The number of time points at which the current characteristic value is greater than or equal to the fifth variance threshold is greater than or equal to a ninth number threshold;

[0306] The number of time points at which the current characteristic value is greater than or equal to the sixth variance threshold is greater than or equal to the tenth number threshold, and the time points at which the current characteristic value is greater than or equal to the sixth variance threshold are within the fifth time length.

[0307] In some embodiments, the current characteristic value includes an absolute value of the current value, and the above step S232 may include the following steps S1701:

[0308] Step S1701, in response to a resistance characteristic value corresponding to at least one time point among a plurality of sampling time points satisfying a third characteristic condition, and an absolute value of a current value corresponding to at least one time point among a plurality of sampling time points satisfying a fourth characteristic condition, controlling any number of switch elements among at least one switch element to be turned off;

[0309] The third characteristic condition includes one of the following:

[0310] The resistance characteristic value corresponding to any time point among the multiple sampling time points is greater than or equal to the seventh resistance threshold;

[0311] The number of time points at which the resistance characteristic value is greater than or equal to the eighth resistance threshold value is greater than or equal to the eleventh number threshold value;

[0312] The number of time points at which the resistance characteristic value is greater than or equal to the ninth resistance threshold value is greater than or equal to the twelfth number threshold value, and the time points at which the resistance characteristic value is greater than or equal to the ninth resistance threshold value are within the sixth time length;

[0313] The fourth characteristic condition includes one of the following:

[0314] The absolute value of the current value corresponding to any time point among the multiple sampling time points is less than or equal to the fourth current threshold;

[0315] The number of time points at which the absolute value of the current value is less than or equal to the fifth current threshold is greater than or equal to the thirteenth number threshold;

[0316] The number of time points at which the absolute value of the current value is less than or equal to the sixth current threshold is greater than or equal to the fourteenth number threshold, and the time points at which the absolute value of the current value is less than or equal to the sixth current threshold are within the seventh time length.

[0317] On this basis, the control method of the heating circuit provided by the embodiment of the present application is explained by taking the scenario of heating a lithium iron phosphate battery product as an example. Figure 8 As shown, the control method of the heating circuit in the battery system includes the following steps S1801 to S1803:

[0318] Step S1801: The BMS collects current signals, or voltage signals and current signals at multiple sampling time points in the loop.

[0319] Here, BMS (Battery Management System) corresponds to the battery management system in the above-mentioned application embodiment.

[0320] The circuit corresponds to the heating circuit in the above-mentioned application embodiment.

[0321] Step S1802: Obtain the resistance characteristic value and / or current characteristic value at each sampling time point through calculation.

[0322] Step S1803: When the BMS detects that the resistance characteristic value and / or the current characteristic value exceeds the preset threshold value for a preset time period, the BMS disconnects the relay.

[0323] Here, the preset time length corresponding to the resistance characteristic value, the preset time length corresponding to the current characteristic value, the preset threshold value corresponding to the resistance characteristic value, the preset threshold value corresponding to the current characteristic value, and the relay may respectively correspond to the first time length, the second time length and / or the third time length, the third resistance threshold value, the third difference threshold value and / or the third current threshold value and the switch element in the above-mentioned application embodiment. The BMS disconnects the relay to stop the heating film from working.

[0324] During implementation, the resistance values ​​at 10 sampling time points can be averaged, and the variance of the resistance value can be calculated based on the average value. When the variance of the resistance value is greater than 5 and lasts for 0.5 seconds, the BMS can control the relay to disconnect. Among them, the maximum threshold value of the variance of the resistance value as the third resistance threshold value can be in the range of not less than 3, and the first duration can be in the range of not less than 0.1 and not greater than 3.3. The process of calculating the variance of the resistance value can refer to formula (1) in the control method of the above-mentioned heating circuit.

[0325] In implementation, when the absolute value of the resistance value is greater than 20W and lasts for 0.6 seconds, the BMS can control the relay to disconnect. The maximum threshold value of the absolute value of the resistance value as the third resistance threshold value may be in a range of not less than 20W, and the first duration may be in a range of not less than 0.1 and not greater than 3.3. The process of calculating the absolute value of the resistance value may refer to formula (2) in the control method of the above-mentioned heating circuit.

[0326] During implementation, the current values ​​at 10 sampling time points can be averaged, and the variance of the current value can be calculated based on the average value. When the variance of the current value is greater than 0.5 and lasts for 0.5 seconds, the BMS can control the relay to disconnect. Among them, the maximum threshold value of the variance of the current value as the third error threshold value can be in the range of not less than 0.3, and the second duration can be in the range of not less than 0.1 and not greater than 3.3. The process of calculating the variance of the current value can refer to formula (3) in the control method of the above heating circuit.

[0327] In implementation, when the absolute value of the current value is less than 8A and lasts for 0.5 seconds, the BMS can control the relay to disconnect. The value range of the minimum threshold of the absolute value of the current value as the third current threshold may be no greater than 10A, and the value range of the third duration may be no less than 0.1 and no greater than 3.3. The process of calculating the absolute value of the current value can refer to formula (4) in the control method of the above heating circuit.

[0328] In the embodiment of the present application, the BMS first collects current signals, or voltage signals and current signals at multiple sampling time points in the loop, and then obtains the resistance characteristic value and / or current characteristic value at each sampling time point by calculation. When the BMS detects that the resistance characteristic value and / or current characteristic value continues to exceed the preset threshold value within the preset time length, the BMS disconnects the relay. In this way, during the operation of the heating film, by judging the size relationship between the characteristic value corresponding to the electrical signal in the loop and the preset threshold value corresponding to the characteristic value, the working state of the loop can be identified, and the switching element in the loop can be more accurately and timely controlled to be turned off, so as to better meet the working requirements of the loop, so that the heating film can stop heating the battery cell more accurately and timely, thereby improving the safety and performance of the battery product.

[0329] The present application embodiment provides a battery system, such as Fig. 9 As shown, the battery system 40 includes at least one battery cell 41 and a battery management system 42 in the above-mentioned application embodiment.

[0330] Here, the battery system may include a system structure with battery cells, which may include but is not limited to a battery pack.

[0331] The present application embodiment provides an electrical device, such as Fig.10As shown, the electrical device 50 includes the battery system 51 in the above-mentioned application embodiment.

[0332] Here, electrical equipment may include but is not limited to automobiles, airplanes, electric bicycles, electric motorcycles, electric motorboats, ships, etc.

[0333] In the description of the present application, the description with reference to the terms "in one embodiment", "in some embodiments", "in other embodiments", "in yet other embodiments", or "exemplary" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In the present application, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0334] The above is only an exemplary embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A battery management system, characterized in that: include: A heating circuit, comprising at least one heating film and at least one switching element, wherein the at least one heating film and the at least one switching element are connected in series, and the heating circuit is used to connect to the total positive electrode and the total negative electrode of the battery system; A controller, used to: control each of the at least one switch element to be turned on, so that the heating film heats the battery cells in the battery system; In the process of the heating film heating the battery cells in the battery system, collecting an electrical signal in the heating circuit; the electrical signal includes a current signal, or the current signal and a voltage signal of at least one heating film; Based on the electrical signals collected at multiple sampling time points, determining the electrical signal characteristic value corresponding to each time point in the multiple sampling time points; Based on the electrical signal characteristic value corresponding to at least one of the time points, controlling any number of the at least one switch element to turn off, so that the heating film stops heating the battery cell; Wherein, the electrical signal characteristic value includes a current characteristic value, and the current characteristic value is used to determine whether the current signal in the heating circuit is in an abnormal state; the controller is also used for one of the following: For each time point among the plurality of sampling time points, determining a current characteristic value corresponding to the time point based on current values ​​corresponding to other time points prior to the time point; The absolute value of the current value corresponding to the current sampling time point is determined as the current characteristic value corresponding to the current sampling time point; The current characteristic value corresponding to the current sampling time point is calculated based on the absolute value of the current value corresponding to the current sampling time point.

2. The battery management system according to claim 1, characterized in that: The electrical signal characteristic value includes a resistance characteristic value; and the controller is further used for: Determining a resistance value corresponding to each time point in the plurality of sampling time points based on the current signal and a voltage signal of at least one heating film; For each time point among the plurality of sampling time points, a resistance characteristic value corresponding to the time point is determined based on resistance values ​​corresponding to other time points prior to the time point.

3. The battery management system according to claim 2, characterized in that: The controller is also used for: In response to a resistance characteristic value corresponding to any time point among the multiple sampling time points being greater than or equal to a first resistance threshold, any number of switch elements among the at least one switch element are controlled to be turned off.

4. The battery management system according to claim 2, characterized in that: The controller is also used for: In response to the number of time points at which the resistance characteristic value is greater than or equal to the second resistance threshold being greater than or equal to a first number threshold, any number of the at least one switch element is controlled to be turned off.

5. The battery management system according to claim 2, characterized in that: The controller is also used for: In response to the number of time points when the resistance characteristic value is greater than or equal to the third resistance threshold being greater than or equal to a second number threshold, and the time points when the resistance characteristic value is greater than or equal to the third resistance threshold being within a first time period, any number of the at least one switching element is controlled to be turned off.

6. The battery management system according to claim 1, characterized in that: The controller is also used for: The variance between the current values ​​corresponding to a plurality of other time points prior to the time point is determined as the current characteristic value corresponding to the time point.

7. The battery management system according to claim 6, characterized in that: The controller is also used for: In response to a current characteristic value corresponding to any time point among the multiple sampling time points being greater than or equal to a first variance threshold, any number of switch elements among the at least one switch element are controlled to be turned off.

8. The battery management system according to claim 6, characterized in that: The controller is also used for: In response to the number of time points at which the current characteristic value is greater than or equal to the second variance threshold being greater than or equal to a third number threshold, any number of the at least one switching element is controlled to be turned off.

9. The battery management system according to claim 6, characterized in that: The controller is also used for: In response to the number of time points when the current characteristic value is greater than or equal to the third difference threshold being greater than or equal to a fourth quantity threshold, and the time points when the current characteristic value is greater than or equal to the third difference threshold being within a second time period, any number of the at least one switching element is controlled to be turned off.

10. The battery management system according to claim 1, characterized in that: The electrical signal characteristic value includes an absolute value of a current value; and the controller is further used for: In response to an absolute value of a current value corresponding to any time point among the plurality of sampling time points being less than or equal to a first current threshold, any number of switch elements among the at least one switch element are controlled to be turned off.

11. The battery management system according to claim 1, characterized in that: The electrical signal characteristic value includes an absolute value of a current value; and the controller is further used for: In response to the number of time points at which the absolute value of the current value is less than or equal to the second current threshold being greater than or equal to a fifth number threshold, any number of the at least one switching element is controlled to be turned off.

12. The battery management system according to claim 1, characterized in that: The electrical signal characteristic value includes an absolute value of a current value; and the controller is further used for: In response to the number of time points when the absolute value of the current value is less than or equal to the third current threshold being greater than or equal to a sixth number threshold, and the time points when the absolute value of the current value is less than or equal to the third current threshold being within a third time period, any number of the at least one switching element is controlled to be turned off.

13. The battery management system according to claim 1, characterized in that: The electrical signal characteristic value includes a resistance characteristic value and a current characteristic value; the controller is also used for: Determining a resistance value corresponding to each time point in the plurality of sampling time points based on the current signal and a voltage signal of at least one heating film; For each time point among the plurality of sampling time points, determining a resistance characteristic value corresponding to the time point based on resistance values ​​corresponding to other time points prior to the time point; For each time point among the plurality of sampling time points, a current characteristic value corresponding to the time point is determined based on current values ​​corresponding to other time points prior to the time point.

14. The battery management system according to claim 13, characterized in that: The controller is also used for: Determine the variance between the current values ​​corresponding to a plurality of other time points prior to the time point as the current characteristic value corresponding to the time point; In response to a resistance characteristic value corresponding to at least one time point among the multiple sampling time points satisfying a first characteristic condition, and a current characteristic value corresponding to at least one time point among the multiple sampling time points satisfying a second characteristic condition, controlling any number of switch elements among the at least one switch element to be turned off; The first characteristic condition includes one of the following: The resistance characteristic value corresponding to any time point among the multiple sampling time points is greater than or equal to a fourth resistance threshold; The number of time points at which the resistance characteristic value is greater than or equal to the fifth resistance threshold is greater than or equal to a seventh number threshold; The number of time points at which the resistance characteristic value is greater than or equal to the sixth resistance threshold is greater than or equal to an eighth number threshold, and the time points at which the resistance characteristic value is greater than or equal to the sixth resistance threshold are within a fourth time length; The second characteristic condition includes one of the following: The current characteristic value corresponding to any time point among the multiple sampling time points is greater than or equal to a fourth variance threshold; The number of time points at which the current characteristic value is greater than or equal to the fifth variance threshold is greater than or equal to a ninth number threshold; The number of time points at which the current characteristic value is greater than or equal to the sixth variance threshold is greater than or equal to a tenth number threshold, and the time points at which the current characteristic value is greater than or equal to the sixth variance threshold are within a fifth time length.

15. The battery management system according to claim 13, characterized in that: The current characteristic value includes an absolute value of the current value; and the controller is further used for: In response to the resistance characteristic value corresponding to at least one time point among the multiple sampling time points satisfying the third characteristic condition, and the absolute value of the current value corresponding to at least one time point among the multiple sampling time points satisfying the fourth characteristic condition, controlling any number of the at least one switching element to be turned off; The third characteristic condition includes one of the following: The resistance characteristic value corresponding to any time point among the multiple sampling time points is greater than or equal to the seventh resistance threshold; The number of time points at which the resistance characteristic value is greater than or equal to an eighth resistance threshold value is greater than or equal to an eleventh number threshold value; The number of time points at which the resistance characteristic value is greater than or equal to the ninth resistance threshold is greater than or equal to a twelfth number threshold, and the time points at which the resistance characteristic value is greater than or equal to the ninth resistance threshold are within a sixth time length; The fourth characteristic condition includes one of the following: The absolute value of the current value corresponding to any time point among the multiple sampling time points is less than or equal to the fourth current threshold; The number of time points at which the absolute value of the current value is less than or equal to the fifth current threshold is greater than or equal to the thirteenth number threshold; The number of time points at which the absolute value of the current value is less than or equal to the sixth current threshold is greater than or equal to a fourteenth number threshold, and the time points at which the absolute value of the current value is less than or equal to the sixth current threshold are within the seventh time length.

16. The battery management system according to any one of claims 1 to 15, characterized in that: The heating film is arranged on the surface of at least one group of the battery cells, and an insulating protective layer is arranged between the heating film and the surface of the battery cells.

17. A method for controlling a heating circuit, characterized in that: A battery management system according to any one of claims 1 to 16; the control method comprising: Controlling each of the at least one switch element to be turned on so that the heating film heats the battery cells in the battery system; In the process of the heating film heating the battery cells in the battery system, collecting an electrical signal in the heating circuit; the electrical signal includes a current signal, or the current signal and a voltage signal of at least one heating film; Based on the electrical signals collected at multiple sampling time points, determining the electrical signal characteristic value corresponding to each time point in the multiple sampling time points; Based on the electrical signal characteristic value corresponding to at least one of the time points, controlling any number of the at least one switch element to turn off, so that the heating film stops heating the battery cell; Wherein, the electrical signal characteristic value includes a current characteristic value, and the current characteristic value is used to determine whether the current signal in the heating circuit is in an abnormal state; the electrical signal collected based on multiple sampling time points, determining the electrical signal characteristic value corresponding to each time point in the multiple sampling time points, includes one of the following: For each time point among the plurality of sampling time points, determining a current characteristic value corresponding to the time point based on current values ​​corresponding to other time points prior to the time point; The absolute value of the current value corresponding to the current sampling time point is determined as the current characteristic value corresponding to the current sampling time point; The current characteristic value corresponding to the current sampling time point is calculated based on the absolute value of the current value corresponding to the current sampling time point.

18. A battery system, characterized in that: include: At least one battery cell and a battery management system as claimed in any one of claims 1 to 16.

19. An electrical equipment, characterized in that: Comprising the battery system as claimed in claim 18.

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