Battery monomer, battery module, battery pack and power utilization device

Abstract

The utility model relates to a battery monomer, a battery module, a battery pack and an electric device, and relates to the technical field of batteries. The battery monomer comprises a first pole and a second pole, and further comprises an induction structure coupled to the first pole and / or the second pole; and the induction structure reduces or blocks the current between the first pole and the second pole under a preset condition. The battery monomer can effectively reduce the spreading of thermal runaway caused by short circuit in the battery pack after thermal runaway.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, battery module, battery pack, and power-consuming device. Background Technology

[0002] When a single battery cell in a battery pack experiences thermal runaway, the high-temperature energy it releases, along with the high-temperature conductive material, can easily trigger a chain reaction that causes other battery cells to experience thermal runaway (i.e., thermal diffusion), which may ultimately damage the entire electrical device.

[0003] Therefore, it is necessary to provide a battery cell, battery module, battery pack, and power device to reduce the spread of thermal runaway within the battery pack after thermal runaway of a battery cell. Utility Model Content

[0004] Based on this, this application provides a battery cell, a battery module, a battery pack, and an electrical device, which can reduce the spread of thermal runaway inside the battery pack after thermal runaway of a battery cell.

[0005] In a first aspect, this application provides a battery cell, which includes a first terminal and a second terminal, and further includes an induction structure coupled to the first terminal and / or the second terminal; the induction structure reduces or blocks the current between the first terminal and the second terminal under preset conditions.

[0006] In the technical solution provided in this application embodiment, when a trigger cell experiences thermal runaway, the sensing structure can reduce or block the current between the first and second terminals of a neighboring cell under preset conditions. This can prevent a new thermal runaway caused by a short circuit in a neighboring cell on the basis of thermal conduction. Here, the trigger cell refers to a battery cell that has already experienced thermal runaway; the neighboring cell can be a battery cell that is spatially adjacent to the trigger cell and has a risk of thermal runaway.

[0007] In some embodiments, the sensing structure includes a positive temperature coefficient thermistor layer, the resistance of which increases when its own temperature is higher than its Curie temperature; the positive temperature coefficient thermistor layer is coated on the first electrode and / or the second electrode.

[0008] In the technical solution provided in this application, the resistance of the positive temperature coefficient (PTC) thermistor increases when its temperature is higher than the Curie temperature. When the ambient temperature is below the Curie temperature, the resistance of the PTC thermistor is low, which can support the normal operation of the battery cell. When the ambient temperature is above the Curie temperature, the resistance of the PTC thermistor increases. When the high-temperature conductive material ejected from the trigger cell connects between the positive and negative terminals of the battery cell that has not experienced thermal runaway, the PTC thermistor acts as a large-value resistor connected in series between the positive and negative terminals of the battery cell, which can effectively reduce or block the current between the positive and negative terminals of the battery cell and effectively prevent heat diffusion.

[0009] In some embodiments, the Curie temperature of the positive temperature coefficient thermistor layer is in the range of 85°C to 110°C.

[0010] In the technical solution provided in this application embodiment, the Curie temperature of the positive temperature coefficient thermistor layer is in the range of 85℃-110℃, which can avoid the problem that the battery cell cannot be used normally due to the premature increase of the resistance of the positive temperature coefficient thermistor layer, and can also avoid the problem of heat diffusion caused by failure to increase the resistance in time.

[0011] In some embodiments, the sensing structure includes a normally closed sensing switch disposed on a first pole and / or a second pole; the normally closed sensing switch opens when its own temperature is higher than a first threshold.

[0012] In the technical solution provided in this application embodiment, by setting an inductive normally closed switch on the first and / or second terminal of the battery cell, when the adjacent or surrounding battery cell experiences thermal runaway, the inductive normally closed switch can automatically open to block the current between the first and second terminals of the current battery cell, thereby preventing the current battery cell from short-circuiting and causing thermal runaway, and blocking the occurrence of new thermal diffusion.

[0013] In some embodiments, the first pole or the second pole includes a first portion and a second portion spaced apart along its axial direction, and a normally closed sensing switch is connected in series between the first portion and the second portion.

[0014] In the technical solution provided in this application embodiment, the normally closed sensing switch is connected in series between the first part and the second part of the pole post, so that the normally closed sensing switch can be opened when its own temperature is higher than the first threshold, thereby avoiding the generation of short circuit current between the first pole post and the second pole post.

[0015] In some embodiments, the battery cell further includes a first fusible element electrically connected between the first terminal and the first electrode plate inside the battery cell and / or a second fusible element electrically connected between the second terminal and the second electrode plate inside the battery cell; the sensing structure includes a first normally open sensing switch electrically connected between the first terminal and the second terminal; the first normally open sensing switch closes when its own temperature is higher than a second threshold.

[0016] In the technical solution provided in this application embodiment, by electrically connecting a first normally open inductive switch between the first and second terminals of a battery cell, when a thermal runaway occurs in an adjacent or surrounding battery cell, the high temperature will cause the first normally open inductive switch of the current cell to close. Furthermore, the first and / or second fuse elements within the current cell will melt, thereby disconnecting the first terminal from the first electrode plate and / or the second terminal from the second electrode plate inside the current cell. This effectively prevents a short circuit between the positive and negative terminals of the current cell from further causing a short circuit between its positive and negative electrodes, thus preventing thermal runaway of the current cell. Moreover, the normally open inductive switch can be integrated during the battery cell manufacturing stage, which is beneficial for industrial mass production.

[0017] In some embodiments, the sensing structure further includes a second normally open sensing switch connected between the first terminal and the second terminal; the second normally open sensing switch closes when its own temperature is higher than a second threshold; the first normally open sensing switch is disposed on the first large surface of the battery cell, and the second normally open sensing switch is disposed on the second large surface of the battery cell.

[0018] The large surface area of ​​a battery cell is the primary region for heat exchange. In the technical solution provided in this application, placing a normally open sensing switch on the large surface of the battery cell allows for timely and accurate sensing of temperature changes, enabling a rapid response. A first normally open sensing switch on the first large surface of the battery cell and a second normally open sensing switch on the second large surface can respectively monitor thermal runaway on their respective sides. When the trigger cell is located on one side of the battery cell, the normally open sensing switch on that side can promptly sense and respond; similarly, when the trigger cell is located on the other side of the battery cell, the normally open sensing switch on that side can also quickly sense and execute the corresponding action. This arrangement achieves effective monitoring and rapid response to thermal runaway propagation from different directions.

[0019] Secondly, this application provides a battery module, which includes a busbar and two or more battery cells. Each battery cell includes a first terminal and a second terminal. The first terminal and the second terminal of the two or more battery cells are coupled to the busbar. At least one of the two or more battery cells is a battery cell according to any of the above-mentioned embodiments.

[0020] In the technical solution provided in this application, at least one of two or more battery cells is set as a battery cell of any of the above embodiments, which can reduce the spread of thermal runaway inside the battery module after the trigger cell in the battery module has thermal runaway.

[0021] In some embodiments, the battery module further includes a second positive temperature coefficient thermistor layer coated on at least a portion of the busbar, the second positive temperature coefficient thermistor layer having increased resistance when its own temperature is higher than its Curie temperature.

[0022] When a battery cell in a battery module experiences thermal runaway, the high-temperature conductive mixture it ejects can easily deposit on the busbar, damaging the busbar's insulation and causing an abnormal short circuit, which in turn can lead to a short circuit between the positive and negative terminals of other battery cells. In the technical solution provided in this application, a second positive temperature coefficient thermistor layer is coated on at least a portion of the busbar, which helps to prevent possible abnormal short circuits.

[0023] In some embodiments, the second positive temperature coefficient thermosensitive layer is located in at least one of the following regions below the busbar: a bending region, a connecting region, and a top-view projection overlapping region.

[0024] Since high-temperature conductive materials tend to accumulate in the bending areas, connection areas, and overlapping areas of the top view projection on the busbar, the technical solution provided in this application provides a second positive temperature coefficient thermistor layer coated in the above-mentioned areas of the busbar. When high-temperature conductive materials accumulate in the above-mentioned areas, possible abnormal short circuits can be cut off more effectively.

[0025] In some embodiments, the busbar includes two or more bus segments spaced apart, and a second normally closed sensing switch is connected in series between two adjacent bus segments. The second normally closed sensing switch opens when its own temperature is greater than a third threshold.

[0026] In the technical solution provided in this application embodiment, a second normally closed inductive switch is connected in series between two adjacent bus sections. When the temperature of the second normally closed inductive switch is higher than a third threshold, it is opened, thereby cutting off possible abnormal short circuits.

[0027] In some embodiments, the second sensing normally closed switch is located in at least one of the following regions of the busbar: a bending region, a connection region, and a top-view projection overlapping region.

[0028] In the technical solution provided in this application embodiment, since high-temperature conductive materials tend to accumulate in the bending area, connection area, and overlapping area of ​​the top view projection on the busbar, a second normally closed sensing switch is provided in the above areas. When high-temperature conductive materials accumulate in the above areas, the temperature of the second normally closed sensing switch itself is higher than the third threshold, and the second normally closed sensing switch is opened, thereby cutting off possible abnormal short circuits.

[0029] In some embodiments, the battery module includes a third normally open inductive switch, which is disposed between two adjacent battery cells of two or more battery cells. The third normally open inductive switch is connected between a first terminal and a second terminal of one of the two adjacent battery cells. The two adjacent battery cells include a first fusible element electrically connected between the first terminal and a first electrode plate inside the battery cell and / or a second fusible element disposed between the second terminal and a second electrode plate inside the battery cell. The third normally open inductive switch includes a first conductive sheet, a first heat-fused insulating sheet, and a second conductive sheet. The first heat-fused insulating sheet is disposed between the first conductive sheet and the second conductive sheet. The side of the first conductive sheet away from the first heat-fused insulating sheet abuts against the large surface or heat-insulating pad of one of the two adjacent battery cells. The side of the second conductive sheet away from the heat-fused insulating sheet abuts against the large surface or heat-insulating pad of the other of the two adjacent battery cells. The first heat-fused insulating sheet melts when its own temperature exceeds a fourth threshold, which is located between 85°C and 110°C.

[0030] In the technical solution provided in this application embodiment, the third inductive normally open switch adopts a structure with a first conductive sheet and a second conductive sheet on both sides and a first thermoplastic insulating sheet in the middle. This structure is placed between adjacent battery cells, and the pressure is provided by the pre-tightening force generated during battery module assembly. When adjacent or surrounding battery cells experience thermal runaway, the first thermoplastic insulating sheet melts, and the first and second conductive sheets adhere under the pressure of the pre-tightening force, thereby reliably realizing the closing function of the third inductive normally open switch.

[0031] In some embodiments, a raised structure is provided on the side of the first conductive sheet and / or the second conductive sheet near the first hot-melt insulating sheet.

[0032] In the technical solution provided in the embodiments of this application, a raised structure may be provided on the side of the first conductive sheet and / or the second conductive sheet near the first hot-melt insulating sheet, so as to better pierce the first hot-melt insulating sheet during the melting process, thereby improving the contact effect of the first conductive sheet and the second conductive sheet.

[0033] In some embodiments, the battery module includes a fourth normally open sensor switch; two adjacent battery cells of two or more battery cells each include a first fusible element disposed between a first terminal and a first electrode plate inside the battery cell and / or a second fusible element disposed between a second terminal and a second electrode plate inside the battery cell; a first terminal of the fourth normally open sensor switch is connected to the first terminal of one of the two adjacent battery cells, a second terminal of the fourth normally open sensor switch is connected to the second terminal of one of the two adjacent battery cells, a third terminal of the fourth normally open sensor switch is connected to the first terminal of the other of the two adjacent battery cells, and a fourth terminal of the fourth normally open sensor switch is connected to the second terminal of the other of the two adjacent battery cells; when the temperature of the fourth normally open sensor switch exceeds a fifth threshold, any two of the first, second, third, and fourth terminals are connected in pairs, and the fifth threshold is located between 85°C and 110°C.

[0034] In the technical solution provided in this application embodiment, two adjacent battery cells share a normally open inductive switch. When a cell experiences thermal runaway and the ambient temperature rises sharply, the normally open inductive switch can connect the first and second terminals in pairs, increasing the melting speed of the internal fuse elements of the two adjacent battery cells. This quickly cuts off the conductive path between the battery cell terminals and the internal electrode plates, effectively preventing thermal runaway of the two currently adjacent battery cells.

[0035] In some embodiments, the fourth normally open inductive switch includes a third conductive sheet, a fourth conductive sheet, a fifth conductive sheet, a sixth conductive sheet, a seventh conductive sheet, a second thermoplastic insulating sheet, and a third thermoplastic insulating sheet; the third conductive sheet is electrically connected to a first terminal, the fourth conductive sheet is electrically connected to a second terminal, and the third and fourth conductive sheets are spaced apart; the fifth conductive sheet is electrically connected to the third terminal, the sixth conductive sheet is electrically connected to the fourth terminal, and the fifth and sixth conductive sheets are spaced apart; the second thermoplastic insulating sheet is disposed between the first side of the seventh conductive sheet and the third conductive sheet, and also between the first side of the seventh conductive sheet and the fourth conductive sheet. The third hot-melt insulating sheet is disposed between the second side of the seventh conductive sheet and the fifth conductive sheet, and between the second side of the seventh conductive sheet and the sixth conductive sheet; the sides of the third and fourth conductive sheets away from the second hot-melt insulating sheet abut against the large surface or large surface heat insulation pad of one of the two adjacent battery cells, and the sides of the fifth and sixth conductive sheets away from the third hot-melt insulating sheet abut against the large surface or large surface heat insulation pad of the other of the two adjacent battery cells; both the second and third hot-melt insulating sheets melt when their own temperature exceeds the fifth threshold.

[0036] The technical solution provided in this application embodiment employs a structure with a third, fourth, fifth, and sixth conductive sheet on both sides, and a second and third hot-melt insulating sheet in the middle. This structure is positioned between adjacent battery cells, with pressure provided by a pre-tightening force. When thermal runaway occurs, the second and third hot-melt insulating sheets melt, and the third, fourth, fifth, and sixth conductive sheets adhere to the seventh conductive sheet under the pressure of the pre-tightening force, thereby achieving the closing function of the fourth normally open inductive switch.

[0037] Thirdly, this application provides a battery pack, which includes a battery module as described in any of the above.

[0038] Fourthly, this application provides an electrical device, which includes a battery module as described above or a battery pack as described above, wherein the battery module or battery pack serves as the power source for the electrical device and / or the energy storage unit for the electrical device. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 These are schematic diagrams of the vehicle structure shown in some embodiments of this specification;

[0041] Figure 2 This is an exploded structural diagram of a battery pack according to some embodiments of this specification;

[0042] Figure 3 This is an exploded structural diagram of a battery cell (without an induction structure) according to some embodiments of this specification.

[0043] Figure 4 This is a schematic diagram of the structure of a battery cell with a positive temperature coefficient thermistor layer, as shown in some embodiments of this specification.

[0044] Figure 5 This is a graph showing the temperature versus time relationship between the trigger cell and neighboring cells according to some embodiments of this specification;

[0045] Figure 6 This is a schematic diagram of the structure of a battery cell equipped with a first inductive normally open switch, according to some embodiments of this specification;

[0046] Figure 7AThis is a schematic diagram of the open state of the normally open inductive switch according to some embodiments of this specification;

[0047] Figure 7B This is a schematic diagram of the closed state of an inductive normally open switch according to some embodiments of this specification;

[0048] Figure 8 This is a schematic diagram of the structure of a battery cell equipped with a first inductive normally open switch and a second inductive normally open switch, according to some embodiments of this specification.

[0049] Figure 9 This is a schematic diagram of the battery module structure shown in some embodiments of this specification (when no sensing structure is provided);

[0050] Figure 10 This is a schematic diagram of the battery pack structure shown in some embodiments of this specification (when no sensing structure is provided);

[0051] Figure 11 This is a schematic diagram of a battery module with a third inductive normally open switch, as shown in some embodiments of this specification.

[0052] Figure 12A This is a schematic diagram of the structure of a third normally open inductive switch according to some embodiments of this specification;

[0053] Figure 12B yes Figure 12A An enlarged schematic diagram of region A shown below;

[0054] Figure 13 This is a schematic diagram of a battery module with a fourth normally open inductive switch, as shown in some embodiments of this specification.

[0055] Figure 14A This is a schematic diagram of the structure of a fourth normally open inductive switch according to some embodiments of this specification;

[0056] Figure 14B yes Figure 14A An enlarged schematic diagram of region B is shown.

[0057] The reference numerals in the attached drawings of the specific embodiments are as follows: 1. Vehicle; 10. Battery pack; 11. Explosion-proof valve; 30. Controller; 40. Motor; 100. Battery module; 110. Housing; 111. First part of housing; 112. Second part of housing; 120. Busbar; 20. Battery cell; 21. Outer shell; 211. End cap; 212. Housing; 22. Electrode assembly; 23. Terminal post; 231. First terminal post; 232. Second terminal post; 24. Insulating component; 25. Pressure relief mechanism; 26. Positive temperature coefficient thermistor layer; 27. Inductive normally open switch; 271. First inductive normally open switch; 272. Second inductive normally open switch; 273. Third inductive normally open switch; 274. Fourth normally open inductive switch; 281. First large surface; 282. Second large surface; 283. Large surface heat insulation pad; 291. First conductive sheet; 292. Second conductive sheet; 293. Third conductive sheet; 294. Fourth conductive sheet; 295. Fifth conductive sheet; 296. Sixth conductive sheet; 297. Seventh conductive sheet; 298. Eighth conductive sheet; 299. Ninth conductive sheet; 2910. First thermoplastic insulating sheet; 2911. Second thermoplastic insulating sheet; 2912. Third thermoplastic insulating sheet; 2913. Raised structure; 2914. First end; 2915. Second end; 2916. Third end; 2917. Fourth end; 2718. Semi-enclosed conductive frame. Detailed Implementation

[0058] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0060] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, "multiple groups" means two or more, and "each" means each of the multiple, unless otherwise explicitly defined.

[0061] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0062] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0063] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0064] The technical solutions described in this application are applicable to various electrical devices that use battery packs, such as mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0065] For ease of explanation, the following embodiments will be described using vehicle 1 as an example of an electrical device.

[0066] Please refer to Figure 1 , Figure 1 This is a structural schematic diagram of vehicle 1 according to some embodiments of this specification. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery pack 10 is installed inside vehicle 1, and the battery pack 10 can be located at the bottom, front, or rear of vehicle 1. The battery pack 10 can be used to power vehicle 1; for example, the battery pack 10 can serve as the operating power source for vehicle 1, or it can be used for the electrical system of vehicle 1, such as to meet the power requirements for starting, navigation, and operation of vehicle 1.

[0067] The vehicle 1 may also include a controller 30 and a motor 40, wherein the controller 30 is used to control the battery pack 10 to supply power to the motor 40.

[0068] In some embodiments of this application, the battery pack 10 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0069] Please refer to Figure 2 , Figure 2 This is an exploded structural diagram of the battery pack 10 according to some embodiments of this specification. The battery pack 10 includes a housing 110 and individual battery cells 20, with the individual battery cells 20 housed within the housing 110. The housing 110 provides space for the individual battery cells 20, and the housing 110 can adopt various structures.

[0070] In some embodiments, the housing 110 may include a first housing portion 111 and a second housing portion 112, which overlap each other and together define a receiving space for accommodating the battery cell 20. The housing 110 formed by the first housing portion 111 and the second housing portion 112 may be of various shapes, such as a cylinder, a cuboid, etc.

[0071] In the battery pack 10, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 20 is housed within the housing 110. Alternatively, the battery pack 10 can also consist of multiple battery cells 20 first connected in series, parallel, or in a mixed configuration to form battery modules, and then these battery modules are connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 110. The battery pack 10 may also include other structures; for example, the battery pack 10 may also include a busbar (such as...). Figure 10 The bus shown is used to realize the electrical connection between multiple battery cells 20.

[0072] Each battery cell 20 can be a rechargeable battery. A rechargeable battery is a battery cell that can be recharged after discharge to reactivate its active materials and continue to be used. Please refer to [link / reference needed]. Figure 3 , Figure 3 This is an exploded structural diagram of a battery cell 20 according to some embodiments of this specification (when no induction structure is provided). The battery cell 20 refers to the smallest unit constituting the battery pack 10. For example... Figure 3As shown, the battery cell 20 is a cuboid, with its height direction being the third direction Z, its length direction being the second direction Y, and its thickness direction being the first direction X. The third direction Z, the second direction Y, and the first direction X are all perpendicular to each other. However, this is not a limitation; in other embodiments of this application, the battery cell 20 may also be other polygonal prisms, flat bodies, or other shapes.

[0073] like Figure 3 As shown, the battery cell 20 includes a housing 21, an electrode assembly 22, and other functional components. The housing 21 may include an end cap 211 and a casing 212. The end cap 211 may be provided with functional components such as terminals 23. The terminals 23 can be electrically connected to the electrode assembly 22 for outputting or inputting electrical energy into the battery cell 20. The terminals 23 may include a first terminal 231 and a second terminal 232. To reduce the risk of short circuit between the terminals 23 and the end cap 211, an insulator 24 may be provided between the terminals 23 and the end cap 211. In some embodiments, the end cap 211 may also be provided with a pressure relief mechanism 25 for releasing internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold.

[0074] The housing 212 is an assembly used to cooperate with the end cap 211 to form the internal environment of the battery cell 20, wherein the formed internal environment can accommodate the electrode assembly 22, electrolyte, and other components. The electrode assembly 22 is the component in the battery cell 20 where the electrochemical reaction occurs. The housing 212 may contain one or more electrode assemblies 22. The electrode assembly 22 is mainly formed by winding or stacking a first electrode and a second electrode, and usually an insulating membrane is provided between the first electrode and the second electrode to prevent short circuit. The first electrode is a positive electrode, and the second electrode is a negative electrode; correspondingly, the first terminal 231 is a positive terminal and the second terminal 232 is a negative terminal; or the first electrode is a negative electrode, and the second electrode is a positive electrode; correspondingly, the first terminal 231 is a negative terminal and the second terminal 232 is a positive terminal.

[0075] A positive electrode plate generally includes a positive current collector and a positive active material layer. The positive active material layer is directly or indirectly coated on the positive current collector. The positive current collector without a positive active material layer protrudes from the positive current collector with a positive active material layer. The positive current collector without a positive active material layer serves as a positive electrode tab. Multiple positive electrode tabs are stacked together and form an electrical connection with the positive electrode post.

[0076] A negative electrode plate generally includes a negative current collector and a negative active material layer. The negative active material layer is directly or indirectly coated on the negative current collector. The negative current collector without a negative active material layer protrudes from the negative current collector with a negative active material layer. The negative current collector without a negative active material layer serves as a negative electrode tab. Multiple negative electrode tabs are stacked together and form an electrical connection with the negative electrode post.

[0077] When a battery cell experiences a short circuit between its positive and negative terminals, that cell will undergo thermal runaway (hereinafter referred to as the "trigger cell"). The temperature of the trigger cell rises sharply, and it may also eject high-temperature conductive materials containing metal particles, electrolyte, and carbon powder. Under these circumstances, battery cells within the battery pack that have not yet experienced thermal runaway often experience external short circuits due to these high-temperature conductive materials. Especially for battery cells adjacent to the trigger cell (hereinafter referred to as "neighboring cells"), the core temperature can easily exceed the separator melting point when short circuits occur on top of thermal conduction, thus triggering new thermal runaway. Ultimately, the battery cells within the battery pack will successively experience thermal runaway, forming a chain reaction, i.e., thermal diffusion.

[0078] To address the problem of thermal runaway propagation caused by short circuits in individual battery cells within the battery pack after thermal runaway, some embodiments of this application propose a specific battery cell. These embodiments utilize an inductive structure coupled to a first and / or second terminal post, which reduces or blocks the current flow between the first and second terminals under preset conditions. This effectively reduces the propagation of thermal runaway within the battery pack after triggering individual cell thermal runaway, thereby improving the battery's safety and reliability.

[0079] The following is for reference. Figures 3 to 8 The structure of the battery cell in some embodiments of this application will be described in detail.

[0080] refer to Figure 3 In some embodiments of this application, the battery cell 20 may include a first terminal 231 and a second terminal 232. The battery cell 20 also includes an inductive structure coupled to the first terminal 231 and / or the second terminal 232. The inductive structure reduces or blocks the current between the first terminal 231 and the second terminal 232 under preset conditions.

[0081] For ease of description, the following example uses the first electrode post 231 as the positive electrode post and the second electrode post 232 as the negative electrode post, with the corresponding first electrode plate as the positive electrode plate and the second electrode plate as the negative electrode plate. More information about the first electrode post 231, the second electrode post 232, the first electrode plate, and the second electrode plate can be found above and in their respective descriptions.

[0082] An inductive structure refers to a component capable of reducing or blocking the current between the first terminal 231 and the second terminal 232 under preset conditions. For example, when a single cell experiences thermal runaway, the inductive structure can increase its own resistance to reduce or block the current between the first terminal 231 and the second terminal 232. Alternatively, the inductive structure can disconnect when a single cell experiences thermal runaway, thereby blocking the current between the first terminal 231 and the second terminal 232. Yet another example is that the inductive structure can become conductive when a single cell experiences thermal runaway, thereby generating current to trigger other protective devices (such as fuses) in the battery cell, ultimately blocking the current between the first terminal 231 and the second terminal 232.

[0083] Coupling refers to the direct or indirect mechanical and / or conductive connection between the induction structure and the first pole 231 and / or the second pole 232. Specifically, it can be a connection such as plating, coating, encapsulation, or welding. This connection can be permanent or detachable.

[0084] Preset conditions refer to conditions that are predetermined to trigger changes in the physical properties or structure of the sensing structure. For example, preset conditions could be ambient temperature, the temperature of the sensing structure itself, or the temperature of the battery cell 20 exceeding a preset temperature. The preset temperature can be determined based on the physical and / or chemical properties of the sensing structure.

[0085] In the technical solution provided in this application embodiment, when a single cell experiences thermal runaway, the sensing structure can reduce or block the current between the first pole 231 and the second pole 232 of the adjacent single cell under preset conditions, which can prevent the adjacent single cell from triggering a new thermal runaway due to superimposed short circuit on the basis of thermal conduction.

[0086] In some embodiments, the sensing structure may include a positive temperature coefficient (PTC) thermistor. The PTC thermistor exhibits increased resistance when its own temperature is above its Curie temperature. The PTC thermistor is coated on a first electrode and / or a second electrode.

[0087] A positive temperature coefficient (PTC) thermistor layer is a functional material layer whose electrical resistance increases when its own temperature is above its Curie temperature. For example, materials for PTC thermistors can include, but are not limited to, doped barium titanate ceramics, polymer composites, and vanadate ceramics. The Curie temperature is the temperature at which the electrical resistance of a PTC thermistor layer undergoes a sudden change.

[0088] Positive temperature coefficient (PTC) thermistors have low resistance at room temperature (some optimized formulations can approach the level of copper), but their resistance increases exponentially when the temperature exceeds their Curie temperature (e.g., 100°C). By adjusting the composition of the PTC thermistor, such as adjusting the doping composition of the ceramic (e.g., strontium, lead, etc.), its Curie temperature can be precisely adjusted.

[0089] Figure 4 This is a schematic diagram of the structure of a battery cell (with a positive temperature coefficient thermistor layer) according to some embodiments of this specification. For example, as shown... Figure 4 As shown, the positive temperature coefficient thermistor layer 26 can be coated on the first pole post 231 and the second pole post 232.

[0090] In the technical solution provided in this application, the resistance of the positive temperature coefficient (PTC) thermistor increases when its temperature is higher than the Curie temperature. When the ambient temperature is lower than the Curie temperature, the resistance of the PTC thermistor is lower, which can support the normal operation of the battery cell. When the ambient temperature is higher than the Curie temperature, the resistance of the PTC thermistor increases. When the high-temperature conductive material ejected from the trigger cell connects between the positive and negative terminals of the battery cell, the PTC thermistor acts as a large-value resistor connected in series between the positive and negative terminals of the battery cell, which can effectively reduce or block the current between the positive and negative terminals of the battery cell and effectively prevent heat diffusion.

[0091] In practical applications, the Curie temperature of the positive temperature coefficient (PTC) thermistor layer can be set according to actual needs or environmental conditions. For example, the Curie temperature can be set higher than the normal operating temperature of the battery cell under the current environment. Alternatively, the Curie temperature can be set with a certain safety threshold (e.g., 10°C) reserved based on the normal operating temperature of the battery cell under the current environment. Understandably, if the Curie temperature of the PTC thermistor layer is too low, it will cause the PTC thermistor layer to increase its resistance prematurely. Even without the risk of thermal runaway, the PTC thermistor layer will reduce the current between the first electrode 231 and the second electrode 232, causing the battery cell to malfunction. If the Curie temperature of the PTC thermistor layer is too high, it will be unable to effectively increase its resistance even with the risk of thermal runaway, thus failing to reduce or block the current between the first electrode 231 and the second electrode 232.

[0092] Figure 5 This is a temperature-time relationship graph of the trigger cell and adjacent cells according to some embodiments of this specification. Normally, the normal operating temperature of a battery cell is below 65°C, and the extreme temperature does not exceed 85°C. If the lower limit of the Curie temperature of the positive temperature coefficient thermistor layer is below 85°C, an increase in resistance may be triggered even when the battery cell is operating normally. Therefore, the lower limit of the Curie temperature of the positive temperature coefficient thermistor layer can be set to 85°C. Figure 5As shown, when a single cell experiences thermal runaway, the temperature of its neighboring cells rapidly rises to over 100°C. Considering the Curie temperature fluctuations of the positive temperature coefficient thermistor layer and the differential fluctuations between battery cells, the upper limit of the Curie temperature of the positive temperature coefficient thermistor layer is set to 110°C. Based on these reasons, in some embodiments, the Curie temperature of the positive temperature coefficient thermistor layer is in the range of 85°C-110°C.

[0093] Because the temperature of neighboring monomers can rapidly rise above 100°C after thermal runaway occurs in the trigger monomer, the lower limit of the Curie temperature of the positive temperature coefficient thermistor can also be set to 100°C. For example, the Curie temperature of the positive temperature coefficient thermistor is in the range of 100°C-110°C.

[0094] In the technical solution provided in this application embodiment, the Curie temperature of the positive temperature coefficient thermistor layer is in the range of 85℃-110℃, which can avoid the problem that the battery cell cannot be used normally due to the premature increase of the resistance of the positive temperature coefficient thermistor layer, and can also avoid the problem of heat diffusion caused by failure to increase the resistance in time.

[0095] In some embodiments, the sensing structure may include a normally closed sensing switch. The normally closed sensing switch is disposed on a first terminal and / or a second terminal. The normally closed sensing switch opens when its own temperature exceeds a first threshold.

[0096] A normally closed inductive switch is a switch that is in a closed conducting state by default and opens when its own temperature exceeds a first threshold. The first threshold is the temperature value that triggers the normally closed inductive switch to open. In some embodiments, the first threshold is in the range of 85℃-110℃. In some embodiments, the first threshold is in the range of 100℃-110℃. The reason for setting the first threshold temperature range is similar to the reason for setting the Curie temperature range of a positive temperature coefficient thermistor, as described above and in related descriptions.

[0097] In some embodiments, the normally closed inductive switch may be integrally disposed on the first pole 231 and / or the second pole 232.

[0098] In the technical solution provided in this application embodiment, by setting a normally closed inductive switch on the first terminal 231 and / or the second terminal 232 of the battery cell, the normally closed inductive switch can automatically open when a thermal runaway occurs in an adjacent or surrounding battery cell. For example, by setting a normally closed inductive switch on the first terminal 231 or the second terminal 232 of the battery cell, when the high-temperature conductive material ejected by the trigger cell comes into contact between the first terminal 231 and the second terminal 232 of the current battery cell, the normally closed inductive switch is equivalent to an open switch connected in series between the positive and negative terminals of the battery cell, thereby blocking the current between the first terminal 231 and the second terminal 232 of the current battery cell, thus preventing a short circuit between the positive and negative terminals of the current battery cell from causing a new thermal runaway and blocking the occurrence of thermal diffusion.

[0099] In some embodiments, the first pole 231 or the second pole 232 may include a first portion and a second portion spaced apart along its axial direction. A normally closed inductive switch may be connected in series between the first portion and the second portion. Here, axial direction refers to the direction parallel to the geometrical central axis of the first pole 231 or the second pole 232. Figure 3 As shown, the axial direction of the first pole post 231 or the second pole post 232 refers to the third direction Z.

[0100] In some embodiments, the first pole 231 or the second pole 232 may include a first portion and a second portion spaced apart along its axial direction. A first temperature sensor sensing a normally closed switch may be connected in series between the first portion and the second portion. The spaced arrangement means that the first portion and the second portion are arranged separately from each other along the axial direction of the first pole 231 or the second pole 232, and a certain distance exists between the first portion and the second portion.

[0101] Taking a normally closed inductive switch disposed in the first pole 231 as an example, the normally closed inductive switch may include a conductive sheet with thermal strain properties, which is disposed between the first part and the second part of the first pole 231. As an example only, an annular insulating gasket is fixedly disposed (e.g., bonded) between the first part and the second part, and the conductive sheet is disposed in the hollow area enclosed by the inner wall of the insulating gasket. When the ambient temperature is low (e.g., not exceeding 85°C or 100°C), the conductive sheet can be in an expanded state, making conductive contact with the first part and the second part of the first pole 231 respectively, so that the normally open inductive switch is in a conducting state. When the ambient temperature rises (e.g., exceeding 85°C or 100°C), the thermally strained conductive sheet contracts and separates from the first part and / or the second part, achieving a state of no conductive contact between the first part and the second part, thereby disconnecting the circuit. Exemplary materials for the conductive sheet with thermal strain properties include, but are not limited to, the following: shape memory alloys (e.g., nickel-titanium alloys), negative thermal expansion alloys (e.g., Invar alloys), etc.

[0102] In the technical solution provided in this application embodiment, the normally closed sensing switch is connected in series between the first part and the second part of the pole post, so that the normally closed sensing switch can be opened when its own temperature is higher than the first threshold, thereby avoiding the generation of short circuit current between the first pole post 231 and the second pole post 232.

[0103] Figure 6 This is a schematic diagram of a battery cell equipped with a first inductive normally open switch, according to some embodiments of this specification.

[0104] In some embodiments, such as Figure 6 As shown, the battery cell may further include a first fusible element (not shown) electrically connected between the first terminal 231 and the first electrode plate inside the battery cell, and / or a second fusible element (not shown) electrically connected between the second terminal 232 and the second electrode plate inside the battery cell. The sensing structure may include a first normally open sensing switch 271. The first normally open sensing switch 271 may be electrically connected between the first terminal 231 and the second terminal 232. The first normally open sensing switch 271 may close when its own temperature is higher than a second threshold.

[0105] A fuse is an overcurrent protection device that operates based on the principle of current heating. When the current flowing through the fuse exceeds its rated value and persists for a certain period of time, the heat generated by the fuse itself will cause its melting point to melt, thereby breaking the circuit and protecting subsequent circuits. The first fuse can be electrically connected between the first terminal 231 and the first electrode plate inside the battery cell, and the second fuse can be electrically connected between the second terminal 232 and the second electrode plate inside the battery cell. Here, "electrical connection" refers to the electrical connection established between the terminal and the electrode plate through a conductor, conductive component, or conductive medium, allowing current to flow. More information about the first terminal 231, the second terminal 232, the first electrode plate, and the second electrode plate can be found above and in their respective descriptions.

[0106] A normally open inductive switch is a switch that is in an open, non-conductive state by default, and closes when its own temperature exceeds a second threshold. The second threshold is the temperature value that triggers the normally open inductive switch to close. In some embodiments, the second threshold is in the range of 85℃-110℃. In some embodiments, the second threshold is in the range of 100℃-110℃. The reason for setting the second threshold temperature range is similar to the reason for setting the Curie temperature range of a positive temperature coefficient thermistor, as described above and in related descriptions.

[0107] Figure 7A This is a schematic diagram of the open state of the normally open inductive switch according to some embodiments of this specification; Figure 7B This is a schematic diagram illustrating the closed state of a normally open inductive switch according to some embodiments of this specification. For example... Figure 7A and Figure 7B As shown, the normally open inductive switch 27 includes a semi-enclosed conductive frame 2718 electrically connected to the second terminal 232, and an eighth conductive piece 298 electrically connected to the first terminal 231. The eighth conductive piece 298 and the ninth conductive piece 299 are made of materials with different coefficients of thermal expansion and are stacked together. Figure 7A As shown, when the ambient temperature is below the sixth threshold, the eighth conductive piece 298 and the ninth conductive piece 299 remain flat and have no conductive contact with the semi-enclosed conductive frame 2718, thus keeping the normally open inductive switch 27 in the open state. Figure 7B As shown, when the ambient temperature rises above the sixth threshold, due to the difference in the coefficients of thermal expansion between the eighth conductive piece 298 and the ninth conductive piece 299, they undergo unequal deformation upon heating, causing them to arch towards the semi-enclosed conductive frame 2718. This arching causes the eighth conductive piece 298 and / or the ninth conductive piece 299 to make physical contact with the semi-enclosed conductive frame 2718, forming an electrical connection path from the first terminal 231 to the second terminal 232, i.e., the switch is switched to a closed state. The sixth threshold is located between 85℃ and 110℃. The sixth threshold is similar to the second threshold, as described above and in related descriptions.

[0108] In some embodiments, the first normally open inductive switch 271 can be... Figure 7A and Figure 7B The normally open inductive switch 27 shown is implemented. The first normally open inductive switch 271 can be disposed on one of the large surfaces, one of the side surfaces, the top surface, or the bottom surface of the battery cell. The large surfaces of the battery cell refer to the two surfaces perpendicular to the first direction X; the side surfaces of the battery cell refer to the two surfaces perpendicular to the second direction Y; the top surface and the bottom surface refer to the two surfaces perpendicular to the third direction Z.

[0109] In some embodiments, the normally open inductive switch can be replaced by a negative temperature coefficient (NTC) thermistor. An NTC thermistor is a component whose resistance decreases when its temperature exceeds its Curie temperature. For example, the material of an NTC thermistor can be, but is not limited to, transition metal oxide ceramics such as manganese, cobalt, and nickel. The Curie temperature is the temperature at which the resistance of an NTC thermistor undergoes a sudden change. At room temperature, an NTC thermistor has a high resistance (some optimized formulations can approach an open circuit), but when the temperature exceeds its Curie temperature (e.g., 100°C), the resistance decreases exponentially. By adjusting the composition of the NTC thermistor, such as adjusting the doping composition of the ceramic (e.g., manganese, cobalt, nickel, etc.), its Curie temperature can be precisely adjusted.

[0110] The negative temperature coefficient thermistor can be electrically connected between the first terminal 231 and the second terminal 232. The negative temperature coefficient thermistor has a high resistance at room temperature (close to an open circuit). When the temperature of the negative temperature coefficient thermistor exceeds the second threshold, the resistance will decrease exponentially (equivalent to a closed circuit).

[0111] In the technical solution provided in this application embodiment, by electrically connecting a first normally open inductive switch 271 between the first and second terminals of a battery cell, when a thermal runaway occurs in an adjacent or surrounding battery cell, the high temperature will cause the first normally open inductive switch of the current cell to close. Furthermore, the first and / or second fuse elements within the current cell will melt, thereby disconnecting the first terminal from the first electrode plate and / or the second terminal from the second electrode plate inside the current cell. This effectively prevents a short circuit between the positive and negative terminals of the current cell from further causing a short circuit between its positive and negative electrodes, thus preventing thermal runaway of the current cell. Moreover, the normally open inductive switch can be integrated during the battery cell manufacturing stage, which is beneficial for industrial mass production.

[0112] Figure 8 This is a schematic diagram of a battery cell equipped with a first inductive normally open switch and a second inductive normally open switch, according to some embodiments of this specification.

[0113] In some embodiments, such as Figure 8 As shown, the sensing structure may further include a second normally open sensing switch 272. The second normally open sensing switch 272 is connected between the first terminal 231 and the second terminal 232. The second normally open sensing switch 272 closes when its own temperature exceeds a second threshold. The first normally open sensing switch 271 is disposed on the first large surface 281 of the battery cell, and the second normally open sensing switch 272 is disposed on the second large surface 282 of the battery cell 20. The first large surface 281 and the second large surface 282 refer to two surfaces perpendicular to the first direction X. In some embodiments, the first normally open sensing switch 271 and the second normally open sensing switch 272 may be... Figure 7A and Figure 7B The normally open inductive switch shown, or Figure 12A The normally open inductive switch shown is used for implementation.

[0114] The large surface area of ​​a battery cell is the primary region for heat exchange. In the technical solution provided in this application, placing a normally open sensing switch on the large surface of the battery cell allows for timely and accurate sensing of temperature changes, enabling a rapid response. A first normally open sensing switch 271 on the first large surface 281 of the battery cell 20 and a second normally open sensing switch 272 on the second large surface 282 of the battery cell 20 can respectively monitor thermal runaway conditions on their respective sides. When the triggering cell is located on one side of the battery cell 20, the normally open sensing switch on that side's large surface can promptly sense and respond; similarly, when the triggering cell is located on the other side of the battery cell 20, the normally open sensing switch on that side's large surface can also quickly sense and execute the corresponding action. This arrangement achieves effective monitoring and rapid response to thermal runaway propagation from different directions.

[0115] The following is for reference. Figures 9 to 14B The structure of the battery module 100 according to some embodiments of this application will be described in detail.

[0116] Figure 9 This is a schematic diagram of the structure of a battery module according to some embodiments of this specification.

[0117] In some embodiments, such as Figure 9 As shown, the battery module 100 may include a busbar 120 and two or more battery cells 20. Figure 9 There are three battery cells 20 in the middle. Each battery cell may include a first terminal 231 and a second terminal 232. The first terminal 231 and the second terminal 232 of two or more battery cells 20 are coupled to the busbar 120, and at least one of the two or more battery cells 20 is a battery cell 20 of any of the above embodiments.

[0118] In the technical solution provided in this application embodiment, at least one of two or more battery cells 20 is set as a battery cell of any of the above embodiments, which can reduce the spread of thermal runaway inside the battery module after the trigger cell in the battery module 100 has thermal runaway.

[0119] Figure 10 This is a schematic diagram of the structure of a battery pack according to some embodiments of this specification, which contains one or more battery modules.

[0120] In some embodiments, such as Figure 10 As shown, the battery module 100 in the battery pack may further include a second positive temperature coefficient thermistor layer (not shown in the figure) coated on at least a portion of the busbar 120. The resistance of the second positive temperature coefficient thermistor layer increases when its own temperature is higher than its Curie temperature. The second positive temperature coefficient thermistor layer is similar to the positive temperature coefficient thermistor layer, as can be seen in the above and related descriptions.

[0121] When a battery cell in a battery module experiences thermal runaway, the high-temperature conductive mixture it ejects can easily deposit on the busbar, damaging the busbar's insulation and causing an abnormal short circuit, which in turn can lead to a short circuit between the positive and negative terminals of other battery cells. In the technical solution provided in this application, a second positive temperature coefficient thermistor layer is coated on at least a portion of the busbar, which helps to prevent possible abnormal short circuits.

[0122] In some embodiments, such as Figure 10 As shown, the second positive temperature coefficient thermistor layer can be located in at least one of the following regions below busbar 120: bending region, connecting region, and overlapping region in top view projection.

[0123] A bending area refers to a non-linear area on the busbar 120, such as an area with a specific angle (e.g., a right angle) and a changed shape (from a straight line to an arc). For example, a bending area of ​​the busbar 120 could be a corner of the busbar, or an area on the busbar that makes way for a battery pack mounting point. A connection area refers to the point where two busbar segments connect (e.g., welded, screwed connections) or where the busbar 120 connects to the terminal post 23 (e.g., welded, screwed connections). A top-view overlapping area refers to an area where the projections of two or more busbar segments may overlap in a top view, even though they are actually installed in separate layers (not in contact). Here, a busbar segment refers to a local structural segment within the busbar 120. For example... Figure 10 As shown, the dashed circle includes the bending region, connecting region, and overlapping region in top view projection described in some embodiments of this specification.

[0124] The structural layout of busbar 120 (e.g., bending areas, connection areas, overlapping areas in top view projection) mainly depends on the mechanical structure of the battery housing and the electrical connection requirements of the series and parallel connections of the battery cells, such as bending to adapt to space and detours to avoid interference. Airflow direction (e.g., Figure 10 The arrows in the diagram are mainly related to the pressure relief direction and channel design of the explosion-proof valve 11. After thermal runaway occurs, the high-temperature conductive material ejected from the trigger unit will move with the airflow. If there are complex structural areas such as bends, connections, and overlapping areas in the top view projection of the manifold in the airflow path, these parts are more likely to block and accumulate the high-temperature conductive material that diffuses with the airflow, thus becoming a risk point for secondary short circuits.

[0125] Since high-temperature conductive materials tend to accumulate in the bending areas, connection areas, and overlapping areas of the top view projection on the busbar 120, the technical solution provided in this application embodiment coats a second positive temperature coefficient thermistor layer in the above-mentioned areas of the busbar. When high-temperature conductive materials accumulate in the above-mentioned areas, possible abnormal short circuits can be cut off more effectively.

[0126] In some embodiments, busbar 120 may include two or more bus segments spaced apart, with a second normally closed sensing switch connected in series between adjacent bus segments. The second normally closed sensing switch opens when its own temperature exceeds a third threshold. The second normally closed sensing switch is similar to the normally closed sensing switch, as described above and in its related description. The third threshold is similar to the second threshold, as described above and in its related description.

[0127] In the technical solution provided in this application embodiment, a second normally closed inductive switch is connected in series between two adjacent bus sections. When the temperature of the second normally closed inductive switch is higher than a third threshold, it is opened, thereby cutting off possible abnormal short circuits.

[0128] In some embodiments, the second normally closed sensing switch may be located in at least one of the following regions below busbar 120: a bend region, a connection region, and a top-view overlapping region. Further details regarding bend regions, connection regions, and top-view overlapping regions can be found above and in their related descriptions.

[0129] In the technical solution provided in this application embodiment, since high-temperature conductive materials tend to accumulate in the bending area, connection area, and overlapping area of ​​the top view projection on the busbar 120, a second normally closed sensing switch is provided in the above areas. When high-temperature conductive materials accumulate in the above areas, the temperature of the second normally closed sensing switch itself is higher than the third threshold, and the second normally closed sensing switch is opened, thereby cutting off possible abnormal short circuits.

[0130] Figure 11 This is a schematic diagram of a battery module with a third inductive normally open switch, as shown in some embodiments of this specification. Figure 12A This is a schematic diagram of the structure of a third normally open inductive switch according to some embodiments of this specification.

[0131] In some embodiments, such as Figure 11 As shown, the battery module 100 may include a third normally open sensor switch 273, which is disposed between two adjacent battery cells 20 of two or more battery cells 20. The third normally open sensor switch 273 is connected between a first terminal 231 and a second terminal 232 of one of the two adjacent battery cells 20. Each of the two adjacent battery cells 20 includes a first fusible element electrically connected between the first terminal 231 and a first electrode plate inside the battery cell, and / or a second fusible element disposed between the second terminal 232 and a second electrode plate inside the battery cell. Figure 12AAs shown, the third normally open inductive switch includes a first conductive sheet 291, a first thermoplastic insulating sheet 2910, and a second conductive sheet 292. The first thermoplastic insulating sheet 2910 is disposed between the first conductive sheet 291 and the second conductive sheet 292. The side of the first conductive sheet 291 away from the first thermoplastic insulating sheet 2910 abuts against the large surface or large surface heat insulation pad 283 of one of the two adjacent battery cells. The side of the second conductive sheet 292 away from the thermoplastic insulating sheet abuts against the large surface or large surface heat insulation pad 283 of the other of the two adjacent battery cells. The first thermoplastic insulating sheet 2910 melts when its own temperature exceeds a fourth threshold, which is located between 85℃ and 110℃. The fourth threshold is similar to the second threshold, as described above and in related descriptions.

[0132] A conductive sheet refers to a sheet-like material that can conduct electricity. For example, the material of a conductive sheet may include, but is not limited to, metals such as copper, nickel, and aluminum. The materials of the first conductive sheet 291 and the second conductive sheet 292 may be the same or different. In some embodiments, the first conductive sheet 291 may be electrically connected to the first terminal 231 of the battery cell 20, and the second conductive sheet 292 may be electrically connected to the second terminal 232 of the battery cell 20.

[0133] Hot-melt insulating sheets are sheet materials that are solid at room temperature but can be melted at a certain temperature. For example, the materials of hot-melt insulating sheets can include, but are not limited to, polyolefins, polyamides, and polyesters.

[0134] In the technical solution provided in this application embodiment, the third inductive normally open switch adopts a structure with a first conductive sheet and a second conductive sheet on both sides and a first thermoplastic insulating sheet in the middle. This structure is placed between adjacent battery cells, and the pressure is provided by the pre-tightening force generated during battery module assembly. When adjacent or surrounding battery cells experience thermal runaway, the first thermoplastic insulating sheet melts, and the first and second conductive sheets adhere under the pressure of the pre-tightening force, thereby reliably realizing the closing function of the third inductive normally open switch.

[0135] In some embodiments, the first conductive sheet 291 and the second conductive sheet 292 may have thermal strain capability. When thermal runaway occurs, the first conductive sheet 291 and the second conductive sheet 292 may expand due to heat, and the pressure between the first conductive sheet 291 and the second conductive sheet 292 may be greater, thereby enabling better contact.

[0136] Figure 12B yes Figure 12A An enlarged schematic diagram of region A shown.

[0137] In some embodiments, a protrusion structure 2913 may be provided on the side of the first conductive sheet 291 and / or the second conductive sheet 292 near the first heat-fused insulating sheet 2910. For example, Figure 12B As shown, a raised structure 2913 may be provided on the side of the first conductive sheet 291 near the first hot-melt insulating sheet 2910. The raised structure 2913 refers to a rigid geometric structure that is locally protruding and has significant three-dimensional dimensions. For example, the raised structure 2913 may include a serrated, conical, pyramidal, blade-shaped, wedge-shaped, or any combination thereof.

[0138] In the technical solution provided in the embodiments of this application, a protruding structure 2913 may be provided on the side of the first conductive sheet 291 and / or the second conductive sheet 292 near the first hot melt insulating sheet 2910, so as to better pierce the first hot melt insulating sheet 2910 during the melting process, thereby improving the contact effect of the first conductive sheet 291 and the second conductive sheet 292.

[0139] Figure 13 This is a schematic diagram of a battery module with a fourth normally open inductive switch, as shown in some embodiments of this specification.

[0140] In some embodiments, such as Figure 13 As shown, the battery module 100 may include a fourth normally open sensor switch 274. Two adjacent battery cells 20 of the two or more battery cells 20 each include a first fusible element disposed between the first terminal 231 and the first electrode plate inside the battery cell and / or a second fusible element disposed between the second terminal 232 and the second electrode plate inside the battery cell; the first end 2914 of the fourth normally open sensor switch 274 is connected to the first terminal 231 of one of the two adjacent battery cells, the second end 2915 of the fourth normally open sensor switch 274 is connected to the second terminal 232 of one of the two adjacent battery cells, the third end 2916 of the fourth normally open sensor switch 274 is connected to the first terminal 231 of the other of the two adjacent battery cells, and the fourth end 2917 of the fourth normally open sensor switch 274 is connected to the second terminal 232 of the other of the two adjacent battery cells. When the temperature of the fourth normally open inductive switch 274 exceeds the fifth threshold, any two of its terminals 2914, 2915, 2916, and 2917 will be connected in pairs. The fifth threshold is located between 85℃ and 110℃. The fifth threshold is similar to the second threshold, as described above.

[0141] In the technical solution provided in this application embodiment, two adjacent battery cells 20 share a fourth normally open sensing switch 274. When a neighboring cell experiences thermal runaway and the ambient temperature rises sharply, the fourth normally open sensing switch 274 can connect the first terminal 231 and the second terminal 232 in pairs, thereby increasing the melting speed of the internal fuse element of the two adjacent battery cells 20, and thus quickly cutting off the conductive path between the battery cell 20 terminal and the internal electrode, effectively preventing the two currently adjacent battery cells 20 from experiencing thermal runaway.

[0142] Figure 14A This is a schematic diagram of the structure of a fourth normally open inductive switch according to some embodiments of this specification.

[0143] In some embodiments, such as Figure 14A As shown, the fourth normally open inductive switch 274 includes a third conductive piece 293, a fourth conductive piece 294, a fifth conductive piece 295, a sixth conductive piece 296, a seventh conductive piece 297, a second thermoplastic insulating piece 2911, and a third thermoplastic insulating piece 2912. The third conductive piece 293 is electrically connected to the first end 2914, and the fourth conductive piece 294 is electrically connected to the second end 2915. The third and fourth conductive pieces 293 and 294 are spaced apart. The fifth conductive piece 295 is electrically connected to the third end 2916, and the sixth conductive piece 296 is electrically connected to the fourth end 2917. The fifth and sixth conductive pieces 295 and 296 are spaced apart. The second thermoplastic insulating piece 2911 is located between the first side of the seventh conductive piece 297 and the third conductive piece 293, and also between the first side of the seventh conductive piece 297 and the fourth conductive piece 294. The third heat-fused insulating sheet 2912 is disposed between the second side of the seventh conductive sheet 297 and the fifth conductive sheet 295, and between the second side of the seventh conductive sheet 297 and the sixth conductive sheet 296. The sides of the third conductive sheet 293 and the fourth conductive sheet 294 away from the second heat-fused insulating sheet 2911 abut against the large surface or large surface heat insulation pad 283 of one of the two adjacent battery cells. The sides of the fifth conductive sheet 295 and the sixth conductive sheet 296 away from the third heat-fused insulating sheet 2912 abut against the large surface or large surface heat insulation pad 283 of the other of the two adjacent battery cells. Both the second heat-fused insulating sheet 2911 and the third heat-fused insulating sheet 2912 melt when their own temperature exceeds the fifth threshold.

[0144] The materials of the third conductive sheet 293, the fourth conductive sheet 294, the fifth conductive sheet 295, the sixth conductive sheet 296, and the seventh conductive sheet 297 can be the same or different. The materials of the second hot-melt insulating sheet 2911 and the third hot-melt insulating sheet 2912 can be the same or different. For more information about conductive sheets and hot-melt insulating sheets, please refer to the above text and its corresponding description.

[0145] Figure 14B yes Figure 14A An enlarged schematic diagram of region B is shown. In some embodiments, the third conductive sheet 293, the fourth conductive sheet 294, the fifth conductive sheet 295, the sixth conductive sheet 296, and / or the seventh conductive sheet 297 may have a protruding structure 2913 on the side near the second heat-fused insulating sheet 2911 and / or the third heat-fused insulating sheet 2912. For example, as... Figure 14B As shown, a raised structure 2913 may be provided on the side of the fourth conductive sheet 294 that is close to the second hot-melt insulating sheet 2911.

[0146] The technical solution provided in this application embodiment employs a structure with a third conductive sheet 293, a fourth conductive sheet 294, a fifth conductive sheet 295, and a sixth conductive sheet 296 on both sides, and a second thermally fusible insulating sheet 2911 and a third thermally fusible insulating sheet 2912 in the middle. This structure is positioned between adjacent battery cells 20, with pressure provided by a pre-tightening force. When thermal runaway occurs, the second thermally fusible insulating sheet 2911 and the third thermally fusible insulating sheet 2912 melt, and the third conductive sheet 293, the fourth conductive sheet 294, the fifth conductive sheet 295, and the sixth conductive sheet 296 adhere to the seventh conductive sheet 297 under the pressure of the pre-tightening force, thereby achieving the closing function of the fourth normally open inductive switch 274.

[0147] According to an embodiment of this application, a battery cell 20 is provided. The battery cell 20 includes a first terminal 231 and a second terminal 232. A positive temperature coefficient (PTC) thermistor layer is coated on the first terminal 231 and / or the second terminal 232. The PTC thermistor layer has increased resistance when its own temperature is higher than its Curie temperature.

[0148] This application also provides a battery pack 10, which includes a battery module 100 as described in any of the above embodiments.

[0149] This application also provides an electrical device, which includes a battery module 100 as described in any of the above embodiments or a battery pack 10 as described above, the battery module or battery pack being used as a power source for the electrical device and / or an energy storage unit for the electrical device.

[0150] The beneficial effects that the embodiments of this specification may bring include, but are not limited to: (1) When a single cell experiences thermal runaway, the sensing structure can reduce or block the current between the first and second terminals of the adjacent single cell under preset conditions, which can prevent the adjacent single cell from superimposed short circuits on the basis of thermal conduction and causing new thermal runaway. (2) Providing a positive temperature coefficient thermistor layer or sensing normally closed switch in at least a part of the busbar of the battery module helps to prevent the high-temperature conductive material ejected when a single cell experiences thermal runaway from causing abnormal short circuits in the busbar, effectively reducing the probability of thermal diffusion in the battery module. It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects that may be produced can be any one or a combination of the above, or any other possible beneficial effects.

[0151] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell (20), comprising a first terminal (231) and a second terminal (232), characterized in that, It also includes an induction structure coupled to the first pole (231) and / or the second pole (232); The sensing structure includes a positive temperature coefficient thermistor layer (26), the resistance of which increases when its own temperature is higher than its Curie temperature. The positive temperature coefficient thermistor layer (26) is coated on the first pole post (231) and / or the second pole post (232).

2. The battery cell (20) as described in claim 1, characterized in that, The Curie temperature of the positive temperature coefficient thermistor layer (26) is in the range of 85℃-110℃.

3. The battery cell (20) as described in claim 1, characterized in that, The sensing structure includes a normally closed sensing switch, which is disposed on the first pole (231) and / or the second pole (232); the normally closed sensing switch opens when its own temperature is higher than a first threshold.

4. The battery cell (20) as described in claim 3, characterized in that, The first pole (231) or the second pole (232) includes a first part and a second part spaced apart along its axial direction, and the normally closed inductive switch is connected in series between the first part and the second part.

5. The battery cell (20) as described in claim 1, characterized in that, The battery cell (20) further includes a first fusible element electrically connected between the first terminal post (231) and the first electrode plate inside the battery cell (20) and / or a second fusible element electrically connected between the second terminal post (232) and the second electrode plate inside the battery cell (20); The sensing structure includes a first normally open sensing switch (271), which is electrically connected between the first terminal (231) and the second terminal (232); the first normally open sensing switch (271) closes when its own temperature is higher than a second threshold.

6. The battery cell (20) as described in claim 5, characterized in that, The sensing structure further includes a second normally open sensing switch (272), which is connected between the first pole (231) and the second pole (232); the second normally open sensing switch (272) closes when its own temperature is higher than the second threshold. The first normally open sensor switch (271) is disposed on the first large surface (281) of the battery cell (20), and the second normally open sensor switch (272) is disposed on the second large surface (282) of the battery cell (20).

7. A battery module (100) comprising a busbar (120) and two or more battery cells (20), each battery cell (20) comprising a first terminal (231) and a second terminal (232), wherein the first terminal (231) and the second terminal (232) of the two or more battery cells (20) are coupled to the busbar (120), characterized in that, At least one of the two or more battery cells (20) is a battery cell (20) as described in any one of claims 1 to 6.

8. The battery module (100) as described in claim 7, characterized in that, It also includes a second positive temperature coefficient thermistor layer coated on at least a portion of the busbar (120), the second positive temperature coefficient thermistor layer having increased resistance when its own temperature is higher than its Curie temperature.

9. The battery module (100) as described in claim 8, characterized in that, The second positive temperature coefficient thermosensitive layer is located in at least one of the following regions below the busbar (120): bending region, connecting region, and overlapping region in top view projection.

10. The battery module (100) as described in claim 7, characterized in that, The busbar (120) includes two or more bus sections spaced apart, and a second normally closed inductive switch is connected in series between two adjacent bus sections. The second normally closed inductive switch is disconnected when its temperature is greater than a third threshold.

11. The battery module (100) as described in claim 10, characterized in that, The second normally closed sensing switch is located in at least one of the following regions below the busbar (120): a bending region, a connecting region, and a region overlapping in top view projection.

12. The battery module (100) as described in claim 7, characterized in that, Includes a third normally open sensor switch (273), which is disposed between two adjacent battery cells (20) of the two or more battery cells (20). The third normally open sensor switch (273) is connected between the first terminal (231) and the second terminal (232) of one of the two adjacent battery cells (20). The two adjacent battery cells (20) include a first fusible element electrically connected between the first terminal (231) and the first electrode plate inside the battery cell (20) and / or a second fusible element disposed between the second terminal (232) and the second electrode plate inside the battery cell (20). The third normally open inductive switch (273) includes a first conductive sheet (291), a first hot melt insulating sheet (2910), and a second conductive sheet (292); the first hot melt insulating sheet (2910) is disposed between the first conductive sheet (291) and the second conductive sheet (292), the side of the first conductive sheet (291) away from the first hot melt insulating sheet (2910) abuts against the large surface or large surface heat insulation pad (283) of one of the two adjacent battery cells (20), and the side of the second conductive sheet (292) away from the hot melt insulating sheet abuts against the large surface or large surface heat insulation pad (283) of the other battery cell (20) of the two adjacent battery cells (20); The first hot-melt insulating sheet (2910) melts when its own temperature exceeds a fourth threshold, which is between 85°C and 110°C.

13. The battery module (100) as described in claim 12, characterized in that, The first conductive sheet (291) and / or the second conductive sheet (292) have a raised structure (2913) on the side near the first hot melt insulating sheet (2910).

14. The battery module (100) as described in claim 7, characterized in that, Including the fourth normally open sensor switch (274); Two adjacent battery cells (20) in the two or more battery cells (20) respectively include a first fusible element disposed between the first terminal post (231) and the first electrode plate inside the battery cell (20) and / or a second fusible element disposed between the second terminal post (232) and the second electrode plate inside the battery cell (20); The first end (2914) of the fourth normally open sensor switch (274) is connected to the first terminal (231) of one of the two adjacent battery cells (20), the second end (2915) of the fourth normally open sensor switch (274) is connected to the second terminal (232) of one of the two adjacent battery cells (20), the third end (2916) of the fourth normally open sensor switch (274) is connected to the first terminal (231) of the other of the two adjacent battery cells (20), and the fourth end of the fourth normally open sensor switch (274) is connected to the second terminal (232) of the other of the two adjacent battery cells (20). When the temperature of the fourth normally open sensor (274) exceeds the fifth threshold, any two of the first terminal (2914), the second terminal (2915), the third terminal (2916), and the fourth terminal are connected in pairs, and the fifth threshold is located between 85℃ and 110℃.

15. The battery module (100) as described in claim 14, characterized in that, The fourth normally open inductive switch (274) includes a third conductive piece (293), a fourth conductive piece (294), a fifth conductive piece (295), a sixth conductive piece (296), a seventh conductive piece (297), a second thermoplastic insulating piece (2911), and a third thermoplastic insulating piece (2912). The third conductive sheet (293) is electrically connected to the first end (2914), and the fourth conductive sheet (294) is electrically connected to the second end (2915). The third conductive sheet (293) and the fourth conductive sheet (294) are arranged at intervals. The fifth conductive piece (295) is electrically connected to the third end (2916), and the sixth conductive piece (296) is electrically connected to the fourth end. The fifth conductive piece (295) and the sixth conductive piece (296) are arranged at intervals. The second hot-melt insulating sheet (2911) is disposed between the first side of the seventh conductive sheet (297) and the third conductive sheet (293), and between the first side of the seventh conductive sheet (297) and the fourth conductive sheet (294); the third hot-melt insulating sheet (2912) is disposed between the second side of the seventh conductive sheet (297) and the fifth conductive sheet (295), and between the second side of the seventh conductive sheet (297) and the sixth conductive sheet (296); The third conductive sheet (293) and the fourth conductive sheet (294) abut against the large surface or large surface heat insulation pad (283) of one of the two adjacent battery cells (20), while the fifth conductive sheet (295) and the sixth conductive sheet (296) abut against the large surface or large surface heat insulation pad (283) of the other of the two adjacent battery cells (20). Both the second hot-melt insulating sheet (2911) and the third hot-melt insulating sheet (2912) melt when their own temperature exceeds the fifth threshold.

16. A battery pack (10), characterized in that, Includes the battery module (100) as described in any one of claims 7 to 15.

17. An electrical appliance, characterized in that, Includes a battery module (100) as described in any one of claims 7 to 15 or a battery pack (10) as described in claim 16, wherein the battery module (100) or the battery pack (10) serves as a power source for the electrical device and / or an energy storage unit for the electrical device.

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