Battery cells, battery devices, and electrical equipment

Abstract

The present application provides a battery cell, a battery device, and an electrical device. The battery cell includes a housing, a battery cell assembly, and a protective structure. The housing has a receiving cavity. The battery cell assembly is disposed within the receiving cavity. The protective structure is disposed between the housing and the battery cell assembly. The protective structure includes a grid structure, a thermally responsive safety agent, and a thermosensitive film. The grid structure has multiple meshes, the thermally responsive safety agent is filled within the meshes, and the thermosensitive film covers the ports of the meshes facing away from the housing. Through the above arrangement, the heat from thermal runaway of the battery cell assembly can be instantly transferred to the thermosensitive film, rapidly releasing the thermally responsive safety agent with a short response delay, which is beneficial to improving the safety performance of the battery cell.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery device, and an electrical device. Background Art

[0002] Battery devices are widely used in consumer electronics, energy storage, power, and other fields. As battery technology continues to advance, the safety requirements for battery devices continue to increase.

[0003] Thermal runaway is one of the factors that affect the safety performance of battery devices. Thermal runaway can cause combustible materials inside the battery to burn, and even cause battery explosion and fire. Summary of the Invention

[0004] The present application provides a battery cell, a battery device, and an electrical device to improve the safety performance of the battery cell.

[0005] In order to solve the above technical problems, the first technical solution adopted in this application is: to provide a battery cell, including a shell, a battery cell assembly, and a protective structure; the shell has a accommodating cavity; the battery cell assembly is arranged in the accommodating cavity; the protective structure is arranged between the shell and the battery cell assembly; the protective structure includes a grid structure, a thermally responsive safety agent and a thermosensitive film; the grid structure has multiple mesh holes, the thermally responsive safety agent is filled in the mesh holes, and the thermosensitive film covers the port of the mesh hole facing away from the shell.

[0006] While the dimensions of the outer shell and the battery cell assembly remain unchanged, compared to the prior art in which a flame retardant is placed in the receiving groove of the inner wall of the outer shell and an organic film is attached to the inner wall of the outer shell, a protective structure is provided between the outer shell and the battery cell assembly. The distance between the thermal sensitive membrane of the protective structure and the battery cell assembly is smaller, and the heat of thermal runaway of the battery cell assembly can be instantly transferred to the thermal sensitive membrane, quickly releasing the thermal responsive safety agent. The response delay is short, and the triggering time is shortened by more than 50% compared to the prior art, which is beneficial to improving the safety performance of the battery cell. In the embodiment of the present application, the thermal responsive safety agent is embedded in the mesh of the grid structure, which does not occupy the internal space of the battery cell assembly and does not affect the energy density and cycle life of the battery cell. The thermal sensitive membrane only melts when the temperature rises abnormally, and the thermal responsive safety agent is released when the temperature rises abnormally, which has little effect on the electrochemical performance of the battery cell under normal operating conditions.

[0007] In one embodiment, the grid structure includes a first area and a second area, wherein the first area is the area of ​​the grid structure adjacent to the tab of the battery cell assembly; the second area is the area of ​​the grid structure other than the first area; the density of the mesh in the first area is greater than the density of the mesh in the second area.

[0008] By setting the mesh density of the first area to be greater than the mesh density of the second area, a larger amount of thermally responsive safety agent can be provided in the first area. The thermally responsive safety agent can wrap the pole ears of the battery cell assembly more tightly, effectively isolating the pole ears of the battery cell assembly from oxygen, blocking the thermal runaway chain reaction at the pole ears of the battery cell assembly, effectively reducing the local temperature rise rate, hindering heat spread, and achieving a safety protection effect.

[0009] In one embodiment, the mesh density of the first region is 300 holes / cm²-400 holes / cm²; and / or the mesh density of the second region is 150 holes / cm²-250 holes / cm².

[0010] By designing the mesh density of the first region and the mesh density of the second region as described above, the mesh density of the first region of the grid structure is greater than the mesh density of the second region. Furthermore, by designing the mesh density of the first region and the mesh density of the second region as described above, a larger amount of thermally responsive safety agent can be stored in the first and second regions. When the thermally sensitive film melts and releases the thermally responsive safety agent during abnormal temperature rise, it can cover most, or even the entire, surface of the battery cell assembly, effectively preventing the temperature of the battery cell assembly from continuing to rise, and achieving a good safety protection effect.

[0011] In one embodiment, the mesh has a pore size of 0.5 mm to 2 mm; and / or a mesh depth of 0.3 mm to 1 mm.

[0012] By designing the aperture and / or depth of the mesh as described above, each mesh can store a larger amount of thermally responsive safety agent. When the temperature of the thermosensitive film melts and releases abnormally high temperatures, the thermally responsive safety agent can cover a larger area of ​​the battery cell component surface, effectively preventing the temperature of the battery cell component from continuing to rise, thereby achieving a good safety protection effect.

[0013] In one embodiment, the thermosensitive film includes a stacked metal foil layer, a bonding layer, and a thermoplastic layer. The metal foil layer is disposed on a side of the bonding layer facing away from the housing, and the thermoplastic layer is disposed on a side of the bonding layer close to the housing.

[0014] By designing the structure of the thermosensitive membrane as described above, it is possible to prevent electrolyte penetration and reduce the agglomeration of the thermal response safety agent due to moisture, while maintaining the structural integrity of the thermosensitive membrane during the charging and discharging process of the battery cell assembly. The thermosensitive membrane can also be melted when the local temperature of the battery cell assembly reaches a threshold, releasing the internal thermal response safety agent to the thermal runaway area for rapid safety protection.

[0015] In one embodiment, the metal foil layer has a hollow structure, and the hollow structure and the mesh are staggered.

[0016] By setting the hollow structure of the metal foil layer and the staggered arrangement of the mesh, the metal foil layer can completely cover the port of the mesh facing away from the shell, and then completely cover the thermally responsive safety agent arranged in the mesh, reducing the moisture and agglomeration of the thermally responsive safety agent arranged in the mesh; at the same time, it is convenient for the thermally responsive safety agent to be released.

[0017] In one embodiment, the metal foil layer comprises aluminum foil; and / or, the tie layer comprises polyethylene; and / or, the thermoplastic layer comprises ethylene vinyl acetate copolymer.

[0018] By arranging the metal foil layer, the bonding layer, and the thermoplastic layer to include the above materials respectively, the melting point of the thermosensitive film is stabilized at 128°C-142°C, which can quickly respond to thermal runaway melting of the battery cell assembly.

[0019] In one embodiment, the thermoplastic layer further comprises nano-silicon dioxide, and the mass percentage of the nano-silicon dioxide in the thermoplastic layer is 1%-4%.

[0020] By adding nano-silicon dioxide into the thermoplastic layer, the thermal response sensitivity of the thermoplastic layer is improved, thereby improving the thermal response sensitivity of the thermosensitive film.

[0021] In one embodiment, the thickness of the metal foil layer is 5 μm to 15 μm; and / or the thickness of the bonding layer is 3 μm to 8 μm; and / or the thickness of the thermoplastic layer is 30 μm to 40 μm.

[0022] By setting the thickness of the metal foil layer, the bonding layer and the thermoplastic layer as described above, under normal operating conditions of the battery cell assembly, the thermosensitive film encapsulates the thermally responsive safety agent in the mesh; and in the event of thermal runaway of the battery cell assembly, the thermosensitive film can quickly respond to the thermal runaway melting of the battery cell assembly.

[0023] In one embodiment, the surface of the thermoplastic layer facing away from the housing is provided with indentations.

[0024] By setting notches on the surface of the thermoplastic layer facing away from the outer shell, the thermoplastic layer will preferentially break along the notches when heated, guiding the thermal responsive safety agent to diffuse directionally to the thermal runaway area of ​​the battery cell assembly, which is beneficial to improving the safety protection effect.

[0025] In one embodiment, the line width of the score is 15 μm to 20 μm; and / or the depth of the score is 30% to 50% of the thickness of the thermoplastic layer.

[0026] By designing the line width and depth of the notches as described above, the thermoplastic layer can better encapsulate the thermally responsive safety agent in the mesh under normal operating conditions of the battery cell assembly. At the same time, after the thermoplastic layer is heated, the notched positions will be preferentially broken, guiding the thermally responsive safety agent to diffuse directionally to the thermal runaway area of ​​the battery cell assembly, which is beneficial to improving the safety protection effect.

[0027] In one embodiment, the grid structure is fixedly connected to the housing.

[0028] By setting a grid structure fixedly connected to the shell, the interference of the protective structure on the assembly process of the battery cell assembly is reduced during the assembly process, and the damage to the protective structure during the assembly process of the battery cell assembly can be reduced.

[0029] In one embodiment, the distance between the protective structure and the battery cell assembly is less than or equal to 0.5 mm.

[0030] By setting the distance between the protective structure and the battery cell assembly to the above range, the distance between the thermal sensitive film of the protective structure and the battery cell assembly is smaller, which is conducive to the thermal sensitive film to quickly respond to thermal runaway of the battery cell assembly, release thermal response safety agent, and achieve good safety protection effect.

[0031] In one embodiment, the battery cell assembly is a rectangular structure, and the battery cell assembly includes two oppositely arranged first side surfaces, two oppositely arranged second side surfaces and two oppositely arranged end surfaces, the area of ​​the first side surface is larger than the area of ​​the second side surface; a protective structure is arranged between the first side surface and the outer shell.

[0032] By setting a protective structure between the first side surface of the battery cell assembly and the outer shell, that is, setting a protective structure between the large surface of the battery cell assembly and the outer shell, in the event of thermal runaway of the battery cell assembly, the thermal response safety agent released by the protective structure can cover most of the surface area of ​​the battery cell assembly, which can effectively block the thermal runaway chain reaction and play a good role in the safety protection of the battery cell against thermal runaway.

[0033] In one embodiment, a protective structure is provided between the second side surface and the outer shell; and / or a protective structure is provided between the end surface and the outer shell.

[0034] By setting a protective structure between the first side of the battery cell assembly and the outer shell, and further setting a protective structure between the second side of the battery cell assembly and the outer shell and / or between the end face of the battery cell assembly and the outer shell, the surface area of ​​the battery cell assembly covered by the thermal response safety agent in the thermal runaway state of the battery cell assembly is further increased, which is conducive to quickly suppressing heat spread and improving the safety protection effect.

[0035] The second technical solution provided by the present application is to provide a battery device comprising any of the above-mentioned battery cells. The battery device has at least the same advantages as the battery cells.

[0036] The third technical solution provided by the present application is to provide an electrical device comprising any one of the battery cells or battery devices described above, wherein the electrical device has at least the same advantages as the battery cells or battery devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 This is a schematic diagram of the structure of the electrical equipment provided in the embodiment of the present application;

[0039] Figure 2 is a schematic structural diagram of a battery device provided in an embodiment of the present application;

[0040] Figure 3 is a schematic structural diagram of a battery cell provided in an embodiment of the present application;

[0041] Figure 4 Schematic diagram of the assembly structure of the protective structure and the housing provided in an embodiment of the present application;

[0042] Figure 5 This is a structural diagram of an embodiment of a mesh structure of a protective structure provided in an embodiment of the present application;

[0043] Figure 6 This is a structural diagram of another embodiment of the mesh structure of the protective structure provided in an embodiment of the present application;

[0044] Figure 7 This is a structural diagram of another embodiment of the mesh structure of the protective structure provided in the embodiment of the present application;

[0045] Figure 8 Schematic diagram of the structure of the heat-sensitive film of the protective structure provided in the embodiment of the present application.

[0046] In the figure: 1. battery device; 11. battery case; 110. accommodating cavity; 111. upper case; 112. lower case; 12. battery cell; 121. outer shell; 1210. accommodating cavity; 1211. shell; 1212. end cover; 122. battery cell assembly; 123. protective structure; 1231. grid structure; 1231a. mesh; A. first area; B. second area; 1232. thermally responsive safety agent; 1233. thermosensitive film; 1233a. metal foil layer; 1233b. bonding layer; 1233c. thermoplastic layer; 124. safety valve; 125. pole; 126. connecting member; 2. equipment body. DETAILED DESCRIPTION

[0047] The following describes the embodiments of the present application in detail with reference to the accompanying drawings.

[0048] In the following description, for the purpose of explanation rather than limitation, specific details such as specific system structures, interfaces, and technologies are provided to facilitate a thorough understanding of the present application.

[0049] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0050] The terms "first," "second," and "third" in this application are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features identified. Therefore, features identified as "first," "second," or "third" may explicitly or implicitly include at least one of such features. In the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined. All directional designations in the embodiments of this application (such as up, down, left, right, front, back, etc.) are intended only to illustrate the relative positional relationships and movement of components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional designations will also change accordingly. Furthermore, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to such process, method, product, or apparatus.

[0051] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0052] Currently, market developments indicate that battery devices are becoming increasingly widely used. These devices can be power batteries, which are used to power tools. Power batteries are commonly found in vehicles like electric vehicles, electric trains, electric bicycles, and golf carts. They can also be storage batteries that power aerospace applications. Of course, battery devices can also be energy storage batteries, which are used to store energy from renewable energy sources such as hydropower, thermal power, wind power, and solar power plants. As the application areas of battery devices continue to expand, market demand is also growing.

[0053] During battery use, if the battery cell is overcharged or the temperature is too high, the electrolyte decomposes, numerous side reactions occur, and the continued rise in temperature causes the separator to shrink further, leading to contact between the positive and negative electrodes, which in turn triggers combustion and produces large amounts of gas. In severe cases, this can cause the battery cell to explode and even cause a fire. Therefore, thermal runaway is one of the factors that affect the safety performance of battery devices.

[0054] To address thermal runaway, existing technology involves creating multiple containment slots on the inner sidewalls of the battery cell housing. These slots are filled with flame retardants and coated with an organic film. When the temperature of a battery cell rises dramatically due to abuse, the organic film melts, releasing the flame retardant from the containment slots. This wraps around the battery cell, isolating it from the outside world and hindering the combustion reaction, thereby improving the safety of the battery cell. However, this existing design suffers from a significant delay in responding to thermal runaway events.

[0055] In order to solve the above technical problems, an embodiment of the present application provides a battery cell, which includes a shell, a battery cell assembly and a protective structure; the shell has a receiving cavity; the battery cell assembly is arranged in the receiving cavity; the protective structure is arranged between the shell and the battery cell assembly; the protective structure includes a grid structure, a thermally responsive safety agent and a thermosensitive film; the grid structure has a plurality of meshes, the thermally responsive safety agent is filled in the meshes, and the thermosensitive film covers the ports of the meshes facing away from the shell. Through the above arrangement, when the outer dimensions of the shell and the battery cell assembly remain unchanged, compared with the prior art in which a flame retardant is arranged in the receiving groove of the inner wall of the shell and an organic film is attached to the inner wall of the shell, a protective structure is arranged between the shell and the battery cell assembly, and the distance between the thermosensitive film of the protective structure and the battery cell assembly is smaller, so that the thermal runaway heat of the battery cell assembly can be instantly transferred to the thermosensitive film, quickly releasing the thermoresponsive safety agent, with a shorter response delay, thereby improving the safety performance of the battery cell.

[0056] The embodiment of the present application provides an electrical device, see Figure 1 , Figure 1 It is a structural diagram of the electrical equipment provided in an embodiment of the present application.

[0057] The electric device may include a device body 2 and a battery device 1, wherein the battery device 1 is provided in the device body 2. The battery device 1 is used to supply power to the electric components of the device body 2 so that the device body 2 can operate.

[0058] An electrical device may be an element that can consume electricity; for example, an electrical device may be a controller and an electronic component, etc. The controller may be a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0059] Electrical equipment can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys and electric tools, etc. Vehicles can be fuel vehicles, gas vehicles or new energy vehicles, and new energy vehicles can be pure electric vehicles, hybrid vehicles or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.; electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers, etc. For the convenience of explanation, the following embodiments are described using the electric equipment as a vehicle as an example.

[0060] In some examples, the electrical device may be a vehicle, the device body 2 may be a vehicle frame, and the battery device 1 may be mounted on the vehicle frame. The electrical components may be vehicle lights (e.g., headlights, taillights, etc.), display screens, instrument panels, control systems (e.g., controllers), etc. The electrical components are mounted on the vehicle body.

[0061] The present application also provides a battery device 1, see Figure 2 , Figure 2 Schematic diagram of the structure of the battery device provided in the embodiment of the present application.

[0062] The battery device 1 includes a battery case 11 and a plurality of battery cells 12 . The battery case 11 forms a receiving chamber 110 . The plurality of battery cells 12 are received in the receiving chamber 110 .

[0063] The battery case 11 can protect the battery cells 12 and facilitate the collection of multiple battery cells 12. In some examples, the battery case 11 can include an upper case 111 and a lower case 112. The upper case 111 covers the lower case 112, and the upper case 111 and the lower case 112 together define a receiving chamber 110 for accommodating the battery cells 12.

[0064] The shape of the battery case 11 can be specifically set as needed; for example, the shape of the battery case 11 can be cylindrical, and the corresponding battery device 1 can be called a round battery; for another example, the shape of the battery case 11 can be rectangular, and the corresponding battery device 1 can be called a rectangular battery.

[0065] In the battery device 1, a battery cell 12 is the smallest unit that makes up the battery device 1. There can be multiple battery cells 12, and these multiple battery cells 12 can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to multiple battery cells 12 being connected both in series and in parallel. Multiple battery cells 12 can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire battery system 12 is housed within the battery housing 11. Alternatively, multiple battery cells 12 can be first connected in series, in parallel, or in a hybrid configuration to form a battery module, and then multiple battery modules can be connected in series, in parallel, or in a hybrid configuration to form a single unit housed within the battery housing 11.

[0066] Each battery cell 12 can be a secondary battery or a primary battery. A secondary battery is a battery cell 12 that can be recharged to activate the active material after discharge, allowing continued use. Battery cells 12 may include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, and the like. Battery cells 12 may be cylindrical, flat, rectangular, or have other shapes.

[0067] The present application also provides a battery cell 12. Figures 3 to 7 , Figure 3 is a schematic structural diagram of a battery cell provided in an embodiment of the present application, Figure 4 : is a schematic diagram of the assembly structure of the protective structure and the housing provided in an embodiment of the present application, Figure 5 This is a structural diagram of an embodiment of the mesh structure of the protective structure provided in the embodiment of the present application. Figure 6 This is a structural diagram of another embodiment of the mesh structure of the protective structure provided in the embodiment of the present application. Figure 7 This is a structural diagram of another embodiment of the mesh structure of the protective structure provided in the embodiment of the present application.

[0068] The battery cell 12 includes a housing 121, a cell assembly 122, and a protective structure 123. The housing 121 has a receiving cavity 1210. The cell assembly 122 is disposed within the receiving cavity 1210. The protective structure 123 is disposed between the housing 121 and the cell assembly 122. The protective structure 123 includes a mesh structure 1231, a thermally responsive safety agent 1232, and a thermosensitive film 1233. The mesh structure 1231 has a plurality of meshes 1231a. The thermally responsive safety agent 1232 is filled within the meshes 1231a. The thermosensitive film 1233 covers the end of the meshes 1231a facing away from the housing 121.

[0069] The outer shell 121 protects the battery cell assembly 122. In one embodiment, the outer shell 121 includes a housing 1211 and an end cap 1212, which define a housing cavity 1210. The housing 1211 has a connected cavity and an installation opening, and the end cap 1212 is connected to the housing 1211 and covers the installation opening. The housing 1211 is a hollow structure and can be made of metal or plastic; for example, materials such as copper, iron, aluminum, steel, and aluminum alloys are included. The outer shell 121 is filled with an electrolyte, such as an electrolyte solution.

[0070] The battery cell assembly 122 may include an anode electrode sheet, a cathode electrode sheet, and a separator disposed between the anode electrode sheet and the cathode electrode sheet. During the charge and discharge process of the battery cell 12, active ions (e.g., lithium ions) are inserted and removed between the anode electrode sheet and the cathode electrode sheet. The separator can prevent the anode electrode sheet and the cathode electrode sheet from shorting to a certain extent, while allowing the active ions to pass through.

[0071] The grid structure 1231 is a grid-like spatial structure composed of intersecting lines, rods or planar units, which form meshes 1231a; the multiple meshes 1231a can be arranged regularly or irregularly, and are designed according to specific needs. The grid structure 1231 serves as a supporting frame for the battery cell assembly 122 and as a carrier for the thermal responsive safety agent 1232 to achieve functional integration. The thermal responsive safety agent 1232 is used to isolate the battery cell assembly 122 from the outside world, specifically to isolate oxygen. The thermal film 1233 is a functional film that is sensitive to temperature. The thermal film 1233 melts at a certain temperature; in the event of thermal runaway of the battery cell assembly 122, the thermal film 1233 melts. When the thermal film 1233 covering the port of mesh 1231a facing away from the housing 121 melts, the thermally responsive safety agent 1232 within the mesh 1231a is released. The thermally responsive safety agent 1232 within each mesh 1231a covers a portion of the surface of the battery cell assembly 122, isolating the battery cell assembly 122 from oxygen, preventing the temperature of the battery cell assembly 122 from continuing to rise, effectively reducing the rate of temperature rise, hindering heat spread, and reducing the probability of explosion and fire, thereby achieving safety protection. For example, when the thermal runaway temperature of the battery cell assembly 122 is greater than 130°C, the thermal film 1233 melts, rapidly releasing the thermally responsive safety agent 1232, achieving an instantaneous fire extinguishing and flame retardant effect, blocking the thermal runaway chain reaction, and simultaneously reducing the rate of temperature rise, providing a safety protection effect for the battery cell against thermal runaway.

[0072] When the outer dimensions of the shell 121 and the battery cell assembly 122 remain unchanged, compared with the prior art in which a flame retardant is arranged in the receiving groove of the inner wall of the shell and an organic film is attached to the inner wall of the shell, a protective structure 123 is arranged between the shell 121 and the battery cell assembly 122. The distance between the thermal sensitive film 1233 of the protective structure 123 and the battery cell assembly 122 is smaller. The thermal runaway heat of the battery cell assembly 122 can be instantly conducted to the thermal sensitive film 1233, quickly releasing the thermal response safety agent 1232, with a short response delay. The triggering time is shortened by more than 50% compared with the prior art, which is beneficial to improving the safety performance of the battery cell.

[0073] In the embodiment of the present application, the thermal responsive safety agent 1232 is designed to be embedded in the mesh 1231a of the grid structure 1231, which does not occupy the internal space of the battery cell assembly 122 and does not affect the energy density and cycle life of the battery cell 12; and the thermosensitive film 1233 only melts when the temperature rises abnormally, and the thermal responsive safety agent 1232 is released when the temperature rises abnormally, which has basically no effect on the electrochemical performance of the battery cell 12 under normal operating conditions.

[0074] In one embodiment, the plurality of mesh holes 1231 a on the mesh structure 1231 are evenly arranged.

[0075] The uniform arrangement of the plurality of meshes 1231a on the mesh structure 1231 refers to the arrangement of the meshes 1231a on the mesh structure 1231 in a regular and consistent manner in terms of aperture size and shape. Figure 5 As shown, the ports of the multiple meshes 1231a on the grid structure 1231 are all circular in shape, and the multiple meshes 1231a are distributed in an array, arranged in multiple rows and columns, with the same spacing between any two adjacent rows and the same spacing between any two adjacent columns.

[0076] By arranging the multiple mesh holes 1231 a on the grid structure 1231 in an even arrangement, the grid structure 1231 is easier to process, and the protective structure 123 achieves a better protective effect on all parts of the battery cell assembly 122 .

[0077] In one embodiment, the grid structure 1231 includes a first area and a second area, the first area is the area of ​​the grid structure 1231 adjacent to the pole ear of the battery cell assembly 122, and the second area is the area of ​​the grid structure 1231 other than the first area; the density of the mesh 1231a in the first area is greater than the density of the mesh 1231a in the second area.

[0078] The density of mesh 1231a refers to the number of meshes 1231a per unit area of ​​the mesh structure 1231, wherein each mesh 1231a is of the same size and shape. The first region is the region of the mesh structure 1231 adjacent to the tab of the cell assembly 122. This can also be understood as the orthographic projection of the first region of the mesh structure 1231 on the cell assembly 122 covering the tab of the cell assembly 122.

[0079] Since the tabs are the "conductive bridges" connecting the positive and negative poles of the battery cell assembly 122 with the external circuit, the current must be conducted through the tabs, resulting in a concentrated current density at the base of the tabs. The high current density will significantly increase the local heat generation of the tabs. The heat generation rate may exceed the heat dissipation rate, causing a sudden temperature rise, which is a high-incidence area for thermal runaway. By setting the mesh density of the first area to be greater than the mesh density of the second area, a larger amount of thermally responsive safety agent 1232 can be provided in the first area. The thermally responsive safety agent 1232 can wrap the tabs of the battery cell assembly 122 more tightly, effectively isolating the tabs of the battery cell assembly 122 from oxygen, blocking the thermal runaway chain reaction at the tabs of the battery cell assembly 122, effectively reducing the local temperature rise rate, hindering heat spread, and achieving a safety protection effect.

[0080] Optionally, the multiple meshes 1231a in the first region of the mesh structure 1231 are evenly arranged, and / or the multiple meshes 1231a in the second region of the mesh structure 1231 are evenly arranged, thereby achieving a good safety protection effect while reducing the structural complexity of the mesh structure 1231. It is understood that the multiple meshes 1231a in the first region of the mesh structure 1231 can be arranged unevenly, and the multiple meshes 1231a in the second region of the mesh structure 1231 can also be arranged unevenly, as long as the density of the meshes 1231a in the first region of the mesh structure 1231 is greater than the density of the meshes 1231a in the second region.

[0081] Optionally, the size of the meshes 1231a in the first area of ​​the mesh structure 1231 is the same as the size of the meshes 1231a in the second area of ​​the mesh structure 1231, and the spacing between two adjacent meshes 1231a in the first area is smaller than the spacing between two adjacent meshes 1231a in the second area, so that the density of the meshes 1231a in the first area is greater than the density of the meshes 1231a in the second area.

[0082] Optionally, the aperture of the meshes 1231a in the first area of ​​the mesh structure 1231 is smaller than the aperture of the meshes 1231a in the second area of ​​the mesh structure 1231, and the spacing between two adjacent meshes 1231a in the first area is the same as the spacing between two adjacent meshes 1231a in the second area, so that the density of the meshes 1231a in the first area is greater than the density of the meshes 1231a in the second area.

[0083] Optionally, the aperture of the meshes 1231a in the first area of ​​the mesh structure 1231 is smaller than the aperture of the meshes 1231a in the second area of ​​the mesh structure 1231, and the spacing between two adjacent meshes 1231a in the first area is smaller than the spacing between two adjacent meshes 1231a in the second area, so that the density of the meshes 1231a in the first area is greater than the density of the meshes 1231a in the second area.

[0084] For example, Figure 6As shown, the grid structure 1231 is divided into a first region A and a second region B. The orthographic projection of the first region A on the battery cell assembly 122 covers the tab of the battery cell assembly 122. The density of the mesh 1231a in the first region A is greater than the density of the mesh 1231a in the second region B. The ports of the multiple meshes 1231a in the first region A are all circular in shape, and the multiple meshes 1231a are distributed in an array, arranged in multiple rows and columns, with the spacing between any two adjacent rows being the same, and the spacing between any two adjacent columns being the same. The ports of the multiple meshes 1231a in the second region B are all circular in shape, and the multiple meshes 1231a are distributed in an array, arranged in multiple rows and columns, with the spacing between any two adjacent rows being the same, and the spacing between any two adjacent columns being the same. The aperture of the mesh 1231a in the first region A is smaller than the aperture of the mesh 1231a in the second region B. The spacing between any two adjacent rows of meshes 1231a in the first area A is smaller than the spacing between any two adjacent rows of meshes 1231a in the second area B, and / or the spacing between any two adjacent columns of meshes 1231a in the first area A is smaller than the spacing between any two adjacent columns of meshes 1231a in the second area B.

[0085] In one embodiment, the density of the mesh 1231a in the first region is 300 holes / cm²-400 holes / cm²; and / or the density of the mesh 1231a in the second region is 150 holes / cm²-250 holes / cm².

[0086] The density of the mesh 1231a in the first area can be 300 holes / cm², 310 holes / cm², 320 holes / cm², 330 holes / cm², 340 holes / cm², 350 holes / cm², 360 holes / cm², 370 holes / cm², 380 holes / cm², 390 holes / cm², 400 holes / cm², etc., or it can be a range consisting of any two of the above values, for example, 300 holes / cm²-350 holes / cm², 320 holes / cm²-380 holes / cm², etc. The density of the mesh 1231a in the second area can be 150 holes / cm², 160 holes / cm², 170 holes / cm², 180 holes / cm², 190 holes / cm², 200 holes / cm², 210 holes / cm², 220 holes / cm², 230 holes / cm², 240 holes / cm², 250 holes / cm², etc., or it can be a range consisting of any two of the above values, for example, 150 holes / cm²-210 holes / cm², 200 holes / cm²-250 holes / cm², etc.

[0087] By designing the density of the mesh 1231a in the first region and the density of the mesh 1231a in the second region as described above, the density of the mesh 1231a in the first region of the grid structure 1231 is greater than the density of the mesh 1231a in the second region. Furthermore, by designing the density of the mesh 1231a in the first region and the density of the mesh 1231a in the second region as described above, a larger amount of thermally responsive safety agent 1232 can be stored in the first and second regions. When the thermally sensitive film 1233 melts and releases the thermally responsive safety agent 1232 during abnormal temperature rise, it can cover the majority of the surface of the battery cell assembly 122, or even the entire surface of the battery cell assembly 122, effectively preventing the temperature of the battery cell assembly 122 from continuing to rise, thereby achieving a good safety protection effect.

[0088] In one embodiment, the pore size of the mesh 1231a is 0.5 mm to 2 mm; and / or the depth of the mesh 1231a is 0.3 mm to 1 mm.

[0089] The aperture of mesh 1231a refers to the aperture of mesh 1231a facing away from the port of housing 121. If mesh 1231a is a circular hole, the aperture of mesh 1231a is the diameter of the circular hole. If mesh 1231a is a non-circular hole, the aperture of mesh 1231a is the maximum length of a line connecting any two points within the hole. For example, if mesh 1231a is a rectangular hole, the aperture of mesh 1231a is the diagonal of the rectangular hole. In another example, if mesh 1231a is a regular hexagonal hole, the aperture of mesh 1231a is the longest diagonal of the regular hexagonal hole.

[0090] The depth of mesh 1231a refers to the dimension of mesh 1231a in the axial direction. Optionally, mesh 1231a is a through hole extending through mesh structure 1231, and the depth of mesh 1231a is equal to the thickness of mesh structure 1231. Optionally, mesh 1231a is a blind hole provided in mesh structure 1231, and the depth of mesh 1231a is the distance between the end of mesh 1231a and the bottom of mesh 1231a.

[0091] The pore size of the mesh 1231a is 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, etc., or may be a range formed by any two of the aforementioned values, for example, 0.5 mm-1.5 mm, 0.6 mm-1.8 mm, etc. The depth of the mesh 1231a is 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, etc., or may be a range formed by any two of the aforementioned values, for example, 0.3 mm-0.8 mm, 0.5 mm-0.9 mm, etc.

[0092] By designing the aperture and / or depth of the mesh 1231a as described above, each mesh 1231a can store a larger amount of thermally responsive safety agent 1232. When the thermosensitive film 1233 melts and releases the thermally responsive safety agent 1232 when the temperature rises abnormally, the thermally responsive safety agent 1232 can cover a larger area of ​​the surface of the battery cell assembly 122, thereby effectively preventing the temperature of the battery cell assembly 122 from continuing to rise, thereby achieving a good safety protection effect.

[0093] In one embodiment, the shape of the mesh 1231a on the grid structure 1231 includes but is not limited to a circle, a triangle, a honeycomb, a square, a diamond, etc., as long as it can store the heat-responsive safety agent 1232. For example, Figure 5 and Figure 6 As shown, the shape of the mesh 1231a is circular. Figure 7 As shown, the shape of the mesh 1231a is triangular.

[0094] In one embodiment, the longitudinal section of the mesh 1231 a is rectangular, wherein the longitudinal section is a section of the mesh 1231 a along its depth direction.

[0095] In one embodiment, the cross-sectional shape of the mesh 1231a is the same along the direction of the battery cell assembly 122 pointing to the housing 121, and the cross-sectional area gradually decreases, wherein the cross-sectional area is parallel to the surface of the housing 121 close to the grid structure 1231.

[0096] In one embodiment, the mesh structure 1231 is formed by a stamping or 3D printing process, and the mesh structure 1231 takes into account both mechanical strength and lightweight requirements.

[0097] In one embodiment, the material of the mesh structure 1231 includes but is not limited to high-strength aluminum alloy, flexible carbon nanotubes, ceramics, and polymers, wherein ceramics include but are not limited to aluminum nitride, silicon nitride, aluminum oxide, and the like.

[0098] In one embodiment, the mesh structure 1231 is formed by a high-strength aluminum alloy through a stamping or 3D printing process. The mesh structure 1231 takes into account both mechanical strength and lightweight requirements.

[0099] In one embodiment, the grid structure 1231 can be a flexible carbon nanotube film or a 3D printed carbon nanotube bracket, or a ceramic-based mesh structure (aluminum nitride, silicon nitride, aluminum oxide), or a polymer-based mesh structure that can be 3D printed into a mesh structure, which has high chemical stability and resistance to electrolyte corrosion.

[0100] In one embodiment, the thermally responsive safety agent 1232 includes a fire extinguishing agent, a heat absorbing agent, a flame retardant, and a protective agent. Optionally, the thermally responsive safety agent 1232 includes a composite dry powder.

[0101] By including a flame retardant in the thermally responsive safety agent 1232, the flame retardant coated on the surface of the battery cell assembly 122 can instantly extinguish fire and retard it, thereby blocking the thermal runaway chain reaction. By including a heat absorbent in the thermally responsive safety agent 1232, the local temperature rise rate can be effectively reduced.

[0102] See also Figure 8 , Figure 8 Schematic diagram of the structure of the heat-sensitive film of the protective structure provided in the embodiment of the present application.

[0103] The thermosensitive film 1233 includes a stacked metal foil layer 1233a, a bonding layer 1233b, and a thermoplastic layer 1233c. The metal foil layer 1233a is disposed on the side of the bonding layer 1233b facing away from the housing 121, and the thermoplastic layer 1233c is disposed on the side of the bonding layer 1233b close to the housing 121.

[0104] Metal foil layer 1233a is used to block electrolyte penetration and reduce moisture and caking of thermally responsive safety agent 1232. It should be noted that, in 85°C / 85% RH testing, the addition of metal foil layer 1233a improved the corrosion resistance of thermally responsive film 1233 by 70% compared to the absence of metal foil layer 1233a. The 85°C / 85% RH test was conducted at 85°C and 85% relative humidity.

[0105] The bonding layer 1233b is used to enhance the toughness of the thermal film 1233 and reduce the risk of thermal film 1233 rupture caused by deformation of the battery cell assembly 122 during charge and discharge. It should be noted that, after testing using the bonding layer 1233b, the integrity rate of the thermal film 1233 exceeded 99.5% after 1,000 battery cycles. The bonding layer 1233b has a certain degree of adhesion, which allows it to bond the metal foil layer 1233a and the thermoplastic layer 1233c located on opposite sides of the bonding layer 1233b, thereby securing the relative positions of the metal foil layer 1233a, the bonding layer 1233b, and the thermoplastic layer 1233c.

[0106] Thermoplastic layer 1233c is used to precisely control its melting point. A temperature-sensitive functional film, thermoplastic layer 1233c melts at a certain temperature. If thermal runaway occurs in the battery cell assembly 122, the thermoplastic layer 1233c also melts. For example, when the thermal runaway temperature of the battery cell assembly 122 exceeds 130°C, the thermoplastic layer 1233c melts, rapidly releasing the thermally responsive safety agent 1232.

[0107] By designing the structure of the thermal-sensitive film 1233 as described above, it is possible to prevent electrolyte penetration and reduce the agglomeration of the thermal-responsive safety agent 1232 due to moisture, while also maintaining the structural integrity of the thermal-sensitive film 1233 during the charging and discharging process of the battery cell assembly 122. Furthermore, the thermal-sensitive film 1233 can be melted when the local temperature of the battery cell assembly 122 reaches a threshold, thereby releasing the internal thermal-responsive safety agent 1232 to the thermal runaway area for rapid safety protection.

[0108] In one embodiment, the metal foil layer 1233a has a hollow structure, and the hollow structure and the mesh 1231a are staggered.

[0109] The staggered arrangement of the hollow structure and the mesh 1231a means that the orthographic projection of the hollow structure on the grid structure 1231 is staggered with the mesh 1231a. The hollow structure is formed on the metal foil layer 1233a by patterning the metal foil layer 1233a.

[0110] By arranging the hollow structure of the metal foil layer 1233a and the mesh 1231a in an offset manner, the metal foil layer 1233a can completely cover the port of the mesh 1231a facing away from the shell 121, and then completely cover the thermally responsive safety agent 1232 arranged in the mesh 1231a, thereby reducing the tendency of the thermally responsive safety agent 1232 arranged in the mesh 1231a to become damp and agglomerated; at the same time, it is convenient for the thermally responsive safety agent 1232 to squeeze through the metal foil layer 1233a, thereby facilitating the release of the thermally responsive safety agent 1232.

[0111] In one embodiment, the metal foil layer 1233a includes aluminum foil; and / or, the bonding layer 1233b includes polyethylene; and / or, the thermoplastic layer 1233c includes ethylene vinyl acetate copolymer.

[0112] By configuring the metal foil layer 1233a to include aluminum foil, the aluminum foil effectively blocks electrolyte penetration. Furthermore, when the thermoplastic layer 1233c melts at a threshold temperature, the thermally responsive safety agent 1232 easily penetrates the aluminum foil, allowing the thermally responsive safety agent 1232 to quickly cover the thermal runaway region of the battery cell assembly 122. By configuring the bonding layer 1233b to include polyethylene, the polyethylene provides sufficient flexibility, mitigating the risk of rupture of the thermosensitive film 1233 caused by deformation during charge and discharge of the battery cell assembly 122. Furthermore, when the thermoplastic layer 1233c melts at a threshold temperature, the thermally responsive safety agent 1232 easily penetrates the polyethylene film, allowing the thermally responsive safety agent 1232 to quickly cover the thermal runaway region of the battery cell assembly 122. By configuring the thermoplastic layer 1233c to include ethylene-vinyl acetate copolymer (EVA), the ethylene-vinyl acetate copolymer film exhibits excellent temperature sensitivity. Upon sensing localized thermal runaway within the battery cell assembly 122, it quickly melts to release the thermally responsive safety agent 1232.

[0113] By arranging the metal foil layer 1233a, the bonding layer 1233b, and the thermoplastic layer 1233c to include the above materials respectively, the melting point of the thermosensitive film 1233 is stabilized at 128°C-142°C, which can quickly respond to thermal runaway melting of the battery cell assembly 122.

[0114] In one embodiment, the thermoplastic layer 1233c further includes nano-silicon dioxide, and the mass percentage of nano-silicon dioxide in the thermoplastic layer 1233c is 1%-4%.

[0115] By adding nano-silicon dioxide to the thermoplastic layer 1233c, the thermal response sensitivity of the thermoplastic layer 1233c is improved, thereby improving the thermal response sensitivity of the thermosensitive film 1233. The mass percentage of nano-silicon dioxide in the thermoplastic layer 1233c can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, etc., or can be a range consisting of any two of the above values, for example, 1%-3%, 1.5%-3.5%, etc.

[0116] In one embodiment, the thickness of the metal foil layer 1233a is 5 μm-15 μm; and / or the thickness of the bonding layer 1233b is 3 μm-8 μm; and / or the thickness of the thermoplastic layer 1233c is 30 μm-40 μm.

[0117] The thickness of metal foil layer 1233a is the vertical distance between the surface of metal foil layer 1233a close to bonding layer 1233b and the surface of metal foil layer 1233a away from bonding layer 1233b. Optionally, the surface of metal foil layer 1233a close to bonding layer 1233b is parallel to the surface of metal foil layer 1233a away from bonding layer 1233b. The thickness of bonding layer 1233b is the vertical distance between the surface of bonding layer 1233b close to metal foil layer 1233a and the surface of bonding layer 1233b close to thermoplastic layer 1233c. Optionally, the surface of bonding layer 1233b close to metal foil layer 1233a is parallel to the surface of bonding layer 1233b close to thermoplastic layer 1233c. The thickness of the thermoplastic layer 1233c is the vertical distance between the surface of the thermoplastic layer 1233c close to the bonding layer 1233b and the surface of the thermoplastic layer 1233c away from the bonding layer 1233b; optionally, the surface of the thermoplastic layer 1233c close to the bonding layer 1233b is parallel to the surface of the thermoplastic layer 1233c away from the bonding layer 1233b.

[0118] The thickness of the metal foil layer 1233a can be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, etc., or can be a range formed by any two of the aforementioned values, for example, 5 μm-10 μm, 7 μm-11 μm, etc. The thickness of the bonding layer 1233b can be 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, etc., or can be a range formed by any two of the aforementioned values, for example, 3 μm-6 μm, 5 μm-8 μm, etc. The thickness of the thermoplastic layer 1233c can be 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, 40μm, etc., or it can be a range consisting of any two of the above values, for example, 30μm-35μm, 33μm-37μm, etc.

[0119] By setting the thickness of metal foil layer 1233a to 5μm-15μm, metal foil layer 1233a can effectively block electrolyte penetration. Furthermore, after thermoplastic layer 1233c is heated and melted at a threshold temperature, thermally responsive safety agent 1232 can easily break through metal foil layer 1233a, allowing thermally responsive safety agent 1232 to quickly cover the thermal runaway region of battery cell assembly 122. By setting the thickness of bonding layer 1233b to 3μm-8μm, bonding layer 1233b can provide sufficient flexibility, reducing the risk of rupture of thermosensitive film 1233 caused by charge and discharge deformation of battery cell assembly 122. Furthermore, after thermoplastic layer 1233c is heated and melted at a threshold temperature, thermally responsive safety agent 1232 can easily break through bonding layer 1233b, allowing thermally responsive safety agent 1232 to quickly cover the thermal runaway region of battery cell assembly 122. By setting the thickness of the thermoplastic layer 1233 c to 30 μm-40 μm, the thermoplastic layer 1233 c can quickly respond by melting when sensing local thermal runaway of the battery cell assembly 122 to release the thermal response safety agent 1232 .

[0120] By setting the thickness of the metal foil layer 1233a, the bonding layer 1233b, and the thermoplastic layer 1233c as described above, under normal operating conditions of the battery cell assembly 122, the thermosensitive film 1233 encapsulates the thermally responsive safety agent 1232 within the mesh 1231a; when the battery cell assembly 122 is in thermal runaway, the thermosensitive film 1233 can quickly respond to the thermal runaway melting of the battery cell assembly 122.

[0121] In one embodiment, the surface of the thermoplastic layer 1233c facing away from the housing 121 is provided with notches.

[0122] By setting notches on the surface of the thermoplastic layer 1233c facing away from the outer shell 121, the thermoplastic layer 1233c will preferentially break along the notch position after being heated, guiding the thermal responsive safety agent 1232 to diffuse directionally to the thermal runaway area of ​​the battery cell assembly 122, which is beneficial to improving the safety protection effect.

[0123] Optionally, micron-scale grid grooves are set on the surface of the thermoplastic layer 1233c using laser micro-etching technology.

[0124] In one embodiment, the line width of the notch is 15 μm-20 μm; and / or the depth of the notch is 30%-50% of the thickness of the thermoplastic layer 1233 c .

[0125] The line width of the score refers to the width of the mark formed on the surface of the thermoplastic layer 1233c by means of scribing, laser micro-etching, etc. The depth of the score refers to the dimension of the mark formed on the surface of the thermoplastic layer 1233c by means of scribing, laser micro-etching, etc. along the thickness direction of the thermoplastic layer 1233c.

[0126] The line width of the score can be 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, etc., or a range formed by any two of the aforementioned values, for example, 15 μm-18 μm, 16 μm-19 μm, etc. The depth of the score can be 30%, 33%, 35%, 37%, 40%, 42%, 45%, 48%, 50%, etc. of the thickness of the thermoplastic layer 1233 c, or a range formed by any two of the aforementioned values, for example, 30%-40%, 33%-42%, etc.

[0127] By designing the line width and depth of the notch as described above, the thermoplastic layer 1233c can better encapsulate the thermally responsive safety agent 1232 in the mesh 1231a under normal operating conditions of the battery cell assembly 122. When the thermoplastic layer 1233c is heated, the notched position will be preferentially broken, guiding the thermally responsive safety agent 1232 to diffuse directionally to the thermal runaway area of ​​the battery cell assembly 122, which is beneficial to improving the safety protection effect.

[0128] In one embodiment, the mesh structure 1231 is fixedly connected to the housing 121. Alternatively, the mesh structure 1231 is welded to the housing 121. Alternatively, the mesh structure 1231 is bonded to the housing 121 via an adhesive layer.

[0129] By providing the grid structure 1231 fixedly connected to the housing 121 , the interference of the protective structure 123 on the assembly process of the battery cell assembly 122 is reduced during the assembly process, and the damage to the protective structure 123 during the assembly process of the battery cell assembly 122 can be reduced.

[0130] In one embodiment, the distance between the protection structure 123 and the battery cell assembly 122 is less than or equal to 0.5 mm.

[0131] The distance between the protective structure 123 and the battery cell assembly 122 is the vertical distance between the surface of the protective structure 123 facing away from the housing 121 and the surface of the battery cell assembly 122 close to the protective structure 123. The distance between the protective structure 123 and the battery cell assembly 122 can be 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.1 mm, 0.01 mm, etc.

[0132] By setting the distance between the protective structure 123 and the battery cell assembly 122 to be within the above range, the distance between the thermal film 1233 of the protective structure 123 and the battery cell assembly 122 is smaller, which is conducive to the thermal film 1233 to quickly respond to the thermal runaway of the battery cell assembly 122, release the thermal response safety agent 1232, and achieve good safety protection effect.

[0133] In one embodiment, the battery cell assembly 122 is a rectangular structure, and the battery cell assembly 122 includes two oppositely arranged first side surfaces, two oppositely arranged second side surfaces and two oppositely arranged end surfaces. The area of ​​the first side surface is larger than the area of ​​the second side surface, and a protective structure 123 is arranged between the first side surface and the outer shell 121.

[0134] By setting a protective structure 123 between the first side surface of the battery cell assembly 122 and the outer shell 121, that is, setting a protective structure 123 between the large surface of the battery cell assembly 122 and the outer shell 121, in the event of thermal runaway of the battery cell assembly 122, the thermal response safety agent 1232 released by the protective structure 123 can cover most of the surface area of ​​the battery cell assembly 122, which can effectively block the thermal runaway chain reaction and achieve good battery cell thermal runaway safety protection effect.

[0135] In one embodiment, a protective structure 123 is provided between the second side surface of the battery cell assembly 122 and the housing 121 ; and / or a protective structure 123 is provided between the end surface of the battery cell assembly 122 and the housing 121 .

[0136] By setting a protective structure 123 between the first side of the battery cell assembly 122 and the outer shell 121, and further setting a protective structure 123 between the second side of the battery cell assembly 122 and the outer shell 121 and / or between the end face of the battery cell assembly 122 and the outer shell 121, the surface area of ​​the battery cell assembly 122 covered by the thermal response safety agent 1232 in the thermal runaway state of the battery cell assembly 122 is further increased, which is conducive to quickly suppressing heat spread and improving the safety protection effect.

[0137] It should be noted that a protective structure 123 is provided between the end face of the battery cell assembly 122 and the housing 121 , and the protective structure 123 needs to avoid the liquid injection hole, the pole and the safety valve.

[0138] In a specific embodiment, a protective structure 123 is arranged between the first side of the battery cell assembly 122 and the outer shell 121 and between the second side of the battery cell assembly 122 and the outer shell 121, that is, a protective structure 123 is arranged on all four sides of the battery cell assembly 122. In the event of thermal runaway of the battery cell assembly 122, the thermal response safety agent 1232 of the protective structure 123 covers the four sides of the battery cell assembly 122.

[0139] In a specific embodiment, a protective structure 123 is provided between all surfaces of the battery cell assembly 122 and the outer shell 121 . In the event of thermal runaway of the battery cell assembly 122 , the thermally responsive safety agent 1232 of the protective structure 123 fully covers the battery cell assembly 122 .

[0140] In one embodiment, the housing 121 is an aluminum shell.

[0141] Continue reading Figure 3 The battery cell 12 may further include a safety valve 124 (also referred to as a pressure relief valve), two poles 125 and two connecting members 126 .

[0142] The safety valve 124 may be provided on the end cap 1212, for example, the safety valve 124 may be fixed to the end cap 1212. The safety valve 124 is configured to be actuated to release the internal electrolyte when the internal pressure or temperature of the battery cell 12 reaches a threshold value, thereby reducing the internal pressure or temperature of the battery cell 12. For example, the safety valve 124 may be a temperature-sensitive valve, a pressure-sensitive valve, or the like.

[0143] The pole 125 can be a conductive component on the outside of the battery cell assembly 122, used to connect to the positive and negative electrodes of the battery cell assembly 122 inside the battery cell 12, and used to provide an interface for current input and output outside the battery cell 12. The pole 125 can be a metal sheet or a metal rod, and the material can include but is not limited to copper, aluminum or other metals with good conductivity. Among them, the cross-section of the pole 125 can include but is not limited to rectangular, circular and elliptical shapes. Two poles 125 can be set on the end cover 1212. The pole 125 can be an electrode terminal. The two poles 125 are respectively a positive electrode terminal and a negative electrode terminal. One pole 125 is connected to a corresponding connecting member 126.

[0144] The connecting member 126 is located between the end cover 1212 and the battery cell assembly 122 and is used to electrically connect the battery cell assembly 122 and the pole 125 .

[0145] The above description is only an implementation method of the present application and does not limit the scope of patent protection of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the scope of patent protection of the present application.

Claims

1. A battery cell, characterized in that: include: a housing having a receiving cavity; A battery cell assembly is disposed in the accommodating cavity; A protective structure is provided between the housing and the battery cell assembly; The protective structure includes a grid structure, a heat-responsive safety agent, and a thermosensitive film; the grid structure has a plurality of meshes, the heat-responsive safety agent is filled in the meshes, and the thermosensitive film covers the ports of the meshes away from the housing; The grid structure includes a first area and a second area, wherein the first area is the area of ​​the grid structure adjacent to the tab of the battery cell assembly; the second area is the area of ​​the grid structure other than the first area; the density of the mesh in the first area is greater than the density of the mesh in the second area.

2. The battery cell according to claim 1, wherein: The mesh density of the first area is 300 holes / cm 2 -400 pores / cm 2 and / or, The mesh density of the second area is 150 holes / cm 2 -250 pores / cm 2 .

3. The battery cell according to claim 1, wherein: The mesh has an aperture of 0.5 mm to 2 mm; and / or the mesh has a depth of 0.3 mm to 1 mm.

4. The battery cell according to claim 1, wherein: The thermosensitive film comprises a stacked metal foil layer, a bonding layer, and a thermoplastic layer. The metal foil layer is arranged on a side of the bonding layer away from the shell, and the thermoplastic layer is arranged on a side of the bonding layer close to the shell.

5. The battery cell according to claim 4, characterized in that The metal foil layer has a hollow structure, and the hollow structure is staggered with the mesh.

6. The battery cell according to claim 4, characterized in that The metal foil layer comprises aluminum foil; and / or, The bonding layer comprises polyethylene; and / or, The thermoplastic layer includes ethylene vinyl acetate copolymer.

7. The battery cell according to claim 6, characterized in that The thermoplastic layer further comprises nano-silicon dioxide, and the mass percentage of the nano-silicon dioxide in the thermoplastic layer is 1%-4%.

8. The battery cell according to claim 4, characterized in that The thickness of the metal foil layer is 5 μm-15 μm; and / or, The thickness of the bonding layer is 3 μm-8 μm; and / or, The thickness of the thermoplastic layer is 30 μm-40 μm.

9. The battery cell according to claim 4, characterized in that The surface of the thermoplastic layer facing away from the housing is provided with scoring.

10. The battery cell according to claim 9, characterized in that The line width of the score is 15 μm-20 μm; and / or the depth of the score is 30%-50% of the thickness of the thermoplastic layer.

11. The battery cell according to claim 1, wherein The grid structure is fixedly connected to the shell.

12. The battery cell according to claim 1, wherein The distance between the protective structure and the battery core assembly is less than or equal to 0.5 mm.

13. The battery cell according to claim 1, characterized in that The battery cell assembly is a rectangular parallelepiped structure, comprising two oppositely arranged first side surfaces, two oppositely arranged second side surfaces and two oppositely arranged end surfaces, wherein the area of ​​the first side surface is greater than the area of ​​the second side surface; the protective structure is arranged between the first side surface and the outer shell.

14. The battery cell according to claim 13, characterized in that The protective structure is provided between the second side surface and the outer shell; and / or the protective structure is provided between the end surface and the outer shell.

15. A battery device, characterized in that: The battery cell comprises the battery cell according to any one of claims 1 to 14.

16. An electrical device, characterized in that: The battery cell comprises the battery cell according to any one of claims 1 to 14 or the battery device according to claim 15.

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