Battery monomer, battery device, electric equipment and energy storage equipment

Abstract

The embodiment of the utility model provides a battery monomer, a battery device, electric equipment and energy storage equipment. The use performance of the battery monomer can be improved. The battery monomer comprises a shell, an electrode assembly, a pressure relief mechanism and an insulating part, the shell comprises a containing cavity, the electrode assembly is contained in the containing cavity, the pressure relief mechanism is arranged on a first wall of the shell, the insulating part is used for wrapping at least part of the surface, facing the shell, of the electrode assembly, and the insulating part comprises a first connecting part opposite to the first wall, the melting point of the first connecting part is smaller than the melting point of the rest part of the insulating part except the first connecting part.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and more specifically, to a battery cell, a battery device, an electrical device, and an energy storage device. Background Art

[0002] Energy conservation and emission reduction are the keys to the sustainable development of the automotive industry. In this context, electric vehicles have become an important part of the sustainable development of the automotive industry due to their advantages of energy conservation and environmental protection. For electric vehicles, battery technology is an important factor related to their development.

[0003] In the development of battery technology, in addition to improving the electrical performance of battery devices, safety issues are also problems that cannot be ignored, such as the thermal runaway problem of battery cells. If the safety of the battery device cannot be guaranteed, the battery device cannot be used, reducing the performance of the battery device. Therefore, how to reduce the risk of thermal runaway diffusion of battery cells and improve the performance of battery cells has become an urgent technical problem in this field. Summary of the Utility Model

[0004] Embodiments of the present application provide a battery cell, a battery device, an electrical device, and an energy storage device, which can improve the performance of the battery cell.

[0005] In a first aspect, a battery cell is provided, including: a housing including a receiving cavity; an electrode assembly received in the receiving cavity; a pressure relief mechanism provided on a first wall of the housing; and an insulating member for wrapping at least a part of a surface of the electrode assembly facing the housing, the insulating member including a first connecting portion opposite to the first wall; wherein, the melting point of the first connecting portion is less than the melting point of the remaining part of the insulating member other than the first connecting portion.

[0006] In the embodiments of the present application, by setting the insulating member to wrap at least a part of the surface of the electrode assembly facing the housing, and the insulating member includes a first connecting portion opposite to the first wall where the pressure relief mechanism is located, and the melting point of the first connecting portion is less than the melting point of the remaining part of the insulating member other than the first connecting portion, in the case of thermal runaway of the battery cell, that is, during the process of increasing the temperature inside the battery cell, the first connecting portion melts earlier than the remaining part of the insulating member other than the first connecting portion, so as to form an exhaust passage communicating with the pressure relief mechanism between the first wall and the surface of the electrode assembly corresponding to the first connecting portion, so that the high-temperature and high-pressure gas generated by the electrode assembly is discharged to the outside of the battery cell through the exhaust passage and the pressure relief mechanism in a directional manner, reducing the risk of damage to the remaining walls of the housing other than the first wall by the high-temperature and high-pressure gas, and at the same time reducing the risk of thermal runaway diffusion, thereby improving the performance of the battery cell.

[0007] In some implementations, the insulating member further includes a second connecting portion connected to the first connecting portion. The first connecting portion is used to cover the first surface of the electrode assembly, and the second connecting portion is used to cover the second surface of the electrode assembly. The area of the second surface is larger than the area of the first surface.

[0008] In the embodiments of the present application, by setting the insulating member to further include a second connecting portion connected to the first connecting portion, and the first connecting portion is used to cover the first surface of the electrode assembly, and the second connecting portion is used to cover the second surface of the electrode assembly, and the area of the second surface is larger than the area of the first surface. In the case of thermal runaway of the battery cell, the first connecting portion melts prior to the second connecting portion, so as to form an exhaust passage communicating with the pressure relief mechanism between the first wall and the first surface, such that the high-temperature and high-pressure gas generated by the electrode assembly is discharged to the outside of the battery cell through the exhaust passage and the pressure relief mechanism in a directional manner, reducing the risk of damage to the wall of the housing opposite to the second surface by the high-temperature and high-pressure gas, that is, reducing the risk of short circuit of the battery cell caused by direct contact between the second surface and the surface of the housing, and at the same time reducing the risk of thermal runaway spread, thereby improving the service performance of the battery cell.

[0009] In some implementations, the melting point T1 of the first connecting portion and the melting point T2 of the second connecting portion satisfy: T2 / T1≥1.5. In this way, in the embodiments of the present application, by setting the melting point T1 of the first connecting portion and the melting point T2 of the second connecting portion to satisfy: T2 / T1≥1.5, in the case of thermal runaway of the battery cell, the first connecting portion can melt preferentially compared with the second connecting portion, so as to form an exhaust passage communicating with the pressure relief mechanism between the first wall and the first surface, such that the high-temperature and high-pressure gas generated by the electrode assembly is discharged to the outside of the battery cell through the exhaust passage and the pressure relief mechanism in a directional manner, reducing the risk of thermal runaway spread, thereby improving the service performance of the battery cell.

[0010] In some implementations, the first connecting portion is provided with a first through hole penetrating the first connecting portion along the thickness direction of the first connecting portion, and the first through hole communicates with the accommodation cavity.

[0011] In the embodiments of the present application, by providing a first through hole penetrating the first connecting portion along the thickness direction of the first connecting portion on the first connecting portion, and the first through hole communicates with the accommodation cavity, in the case of thermal runaway of the battery cell, the first connecting portion can be melted quickly, so as to form an exhaust passage communicating with the pressure relief mechanism between the first wall and the first surface, such that the high-temperature and high-pressure gas generated by the electrode assembly is discharged to the outside of the battery cell through the exhaust passage and the pressure relief mechanism in a directional and quick manner, reducing the risk of thermal runaway spread, thereby improving the service performance of the battery cell.

[0012] In some implementations, the first connecting portion is provided with a plurality of the first through holes, and the plurality of the first through holes are arranged at intervals in a first direction perpendicular to the thickness direction of the first connecting portion.

[0013] In the embodiments of the present application, by providing a plurality of the first through holes on the first connecting portion, and the plurality of the first through holes are arranged at intervals in a first direction perpendicular to the thickness direction of the first connecting portion, in the case of thermal runaway of the battery cell, the melting of the first connecting portion can be further accelerated to form an exhaust passage communicating with the pressure relief mechanism between the first wall and the first surface, so that the high-temperature and high-pressure gas generated by the electrode assembly can be discharged to the outside of the battery cell through the exhaust passage and the pressure relief mechanism in a directional and rapid manner, reducing the risk of thermal runaway diffusion, thereby improving the service performance of the battery cell.

[0014] In some implementations, the first connecting portion is provided with a weak area configured to melt when the temperature in the accommodation cavity reaches a threshold, so as to form an exhaust passage communicating with the pressure relief mechanism between the first surface and the first wall.

[0015] In the embodiments of the present application, by providing a weak area on the first connecting portion, and the weak area is configured to melt when the temperature in the accommodation cavity reaches a threshold, so as to form an exhaust passage communicating with the pressure relief mechanism between the first surface and the first wall, so that the high-temperature and high-pressure gas generated by the electrode assembly can be discharged to the outside of the battery cell through the exhaust passage and the pressure relief mechanism in a directional and rapid manner, reducing the risk of thermal runaway diffusion, thereby improving the service performance of the battery cell. At the same time, in the case of no thermal runaway, the setting of the weak area can also reduce the risk of short circuit caused by direct contact between the housing and the electrode assembly.

[0016] In some implementations, the thickness of the weak area is less than the thickness of the remaining area of the first connecting portion except the weak area, and / or the weak area is provided with a notch on the surface perpendicular to the thickness direction of the first connecting portion.

[0017] In the embodiments of the present application, by setting the thickness of the weak area to be less than the thickness of the remaining area of the first connecting portion except the weak area, and / or by providing a notch on the surface of the weak area in the direction perpendicular to the thickness of the first connecting portion, in the case of thermal runaway of the battery cell, melting can preferentially occur at the weak area of the first connecting portion, and further accelerate the melting of the first connecting portion, so as to form an exhaust passage communicating with the pressure relief mechanism between the first wall and the first surface, enabling the high-temperature and high-pressure gas generated by the electrode assembly to be discharged out of the battery cell directionally and quickly through the exhaust passage and the pressure relief mechanism, reducing the risk of thermal runaway diffusion, thereby improving the service performance of the battery cell. At the same time, the implementation method of the weak area is simple, easy to process and manufacture, and the manufacturing cost is reduced.

[0018] In some implementation manners, the electrode assembly is provided with a tab, and the tab faces the second wall of the battery cell, and the second wall is different from the first wall. In this way, in the embodiments of the present application, by setting the tab to face the second wall of the battery cell to be different from the first wall, in the case of thermal runaway of the battery cell, an exhaust passage communicating with the pressure relief mechanism can be formed between the first wall and the first surface, enabling the high-temperature and high-pressure gas generated by the electrode assembly to be discharged out of the battery cell directionally and quickly through the exhaust passage and the pressure relief mechanism, reducing the risk of damage to the tab during the pressure relief process, and reducing the risk of thermal runaway diffusion, thereby improving the service performance of the battery cell.

[0019] In some implementation manners, the electrode assembly includes two tabs arranged oppositely, and the two tabs respectively face two second walls of the battery cell arranged oppositely, and the first wall connects the two second walls.

[0020] In the embodiments of the present application, by setting the electrode assembly to include two tabs arranged oppositely, and the two tabs respectively face two second walls of the battery cell arranged oppositely, and the first wall connects the two second walls, in the case of thermal runaway of the battery cell, an exhaust passage communicating with the pressure relief mechanism can be formed between the first wall and the first surface, enabling the high-temperature and high-pressure gas generated by the electrode assembly to be discharged out of the battery cell directionally and quickly through the exhaust passage and the pressure relief mechanism, reducing the risk of damage to the two tabs during the pressure relief process, and reducing the risk of thermal runaway diffusion, thereby improving the service performance of the battery cell.

[0021] In some implementation manners, the housing includes two first openings arranged oppositely, the battery cell includes two end caps arranged oppositely, and the two end caps are respectively used to cover the two first openings, and the end cap is the second wall.

[0022] In the embodiments of the present application, by setting the housing to include two first openings arranged oppositely, the battery cell includes two end caps arranged oppositely, and the two end caps are respectively used to cover the two first openings. The end cap is the second wall. In the case of thermal runaway of the battery cell, an exhaust passage communicating with the pressure relief mechanism can be formed between the first wall and the first surface, so that the high-temperature and high-pressure gas generated by the electrode assembly can be discharged to the outside of the battery cell rapidly and directionally through the exhaust passage and the pressure relief mechanism, reducing the risk of damage to the two tabs and the end cap during the pressure relief process, and reducing the risk of thermal runaway diffusion, thereby improving the use performance of the battery cell.

[0023] In some implementation manners, a connection area is provided on the surface of the second connection portion close to the first connection portion, and the first connection portion is fixedly connected to the connection area. In a plane perpendicular to the thickness direction of the first connection portion, at least a part of the orthographic projection of the first connection portion covers the orthographic projection of the connection area.

[0024] In the embodiments of the present application, by setting the first connection portion to be fixedly connected to the connection area, and in a plane perpendicular to the thickness direction of the first connection portion, at least a part of the orthographic projection of the first connection portion covers the orthographic projection of the connection area, it is convenient for the fixed connection between the first connection portion and the second connection portion, and this connection method is simple and feasible, which can effectively improve the processing and manufacturing efficiency of the insulating part and reduce the manufacturing cost.

[0025] In some implementation manners, the first connection portion is a double-layer structure with at least partial overlap, and the double-layer structure is stacked along the thickness direction of the first connection portion.

[0026] In the embodiments of the present application, by setting the first connection portion to be a double-layer structure with at least partial overlap, and the double-layer structure is stacked along the thickness direction of the first connection portion, in the case of thermal runaway of the battery cell, it is convenient to form an exhaust passage with a larger space communicating with the pressure relief mechanism between the first wall and the first surface, so that the high-temperature and high-pressure gas generated by the electrode assembly can be discharged to the outside of the battery cell rapidly and directionally through the exhaust passage and the pressure relief mechanism, and effectively reduce the risk of thermal runaway diffusion, thereby improving the use performance of the battery cell.

[0027] In some implementations, the thickness D1 of the first connecting portion satisfies: 0.1 mm ≤ D1 ≤ 5 mm. In this way, in the embodiments of the present application, by setting the thickness D1 of the first connecting portion to be greater than or equal to 0.1 mm and less than or equal to 5 mm, in the case of thermal runaway of the battery cell, it is convenient to form an exhaust passage with sufficient space communicating with the pressure relief mechanism between the first wall and the first surface, so that the high-temperature and high-pressure gas generated by the electrode assembly can be discharged to the outside of the battery cell through the exhaust passage and the pressure relief mechanism in a directional and rapid manner, and the risk of thermal runaway diffusion is effectively reduced, thereby improving the use performance of the battery cell, while taking into account the structural strength of the insulating member and the energy density of the battery cell.

[0028] In some implementations, the thickness D2 of the second connecting portion satisfies: 0.05 mm ≤ D2 ≤ 0.5 mm. In this way, in the embodiments of the present application, by setting the thickness D2 of the second connecting portion to be greater than or equal to 0.05 mm and less than or equal to 0.5 mm, the structural strength of the insulating member and the energy density of the battery cell are taken into account.

[0029] In a second aspect, a battery device is provided, including: a plurality of battery cells, and the battery cell is the battery cell in the first aspect or its various implementations above.

[0030] In a third aspect, an electrical device is provided, including the battery device described in the second aspect, and the battery device is used to provide electrical energy for the electrical device.

[0031] In some implementations, the electrical device can be a vehicle, a ship, a spacecraft, etc.

[0032] In a fourth aspect, an energy storage device is provided, including the battery device described in the second aspect, and the battery device is used to store electrical energy for the energy storage device. Description of the Drawings

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced below. Obviously, the following described drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to the drawings without creative efforts.

[0034] Figure 1 It is a schematic structural diagram of a vehicle provided by an embodiment of the present application.

[0035] Figure 2 It is a schematic structural diagram of a battery device provided by an embodiment of the present application.

[0036] Figure 3 It is a schematic structural diagram of a battery cell provided by an embodiment of the present application.

[0037] Figure 4 It is a schematic diagram of the explosion structure of a battery cell provided by another embodiment of the present application.

[0038] Figure 5 It is a schematic diagram of the structure of an insulating member provided by an embodiment of the present application.

[0039] Figure 6 It is a schematic diagram of the structure of an insulating member provided by another embodiment of the present application.

[0040] Figure 7 It is a schematic diagram of the structure of a battery cell provided by another embodiment of the present application.

[0041] Figure 8 It is a cross-sectional schematic diagram of a battery cell provided by an embodiment of the present application.

[0042] Figure 9 It is a cross-sectional schematic diagram of a battery cell provided by another embodiment of the present application.

[0043] Figure 10 It is a schematic diagram of the structure of a first connection part provided by an embodiment of the present application.

[0044] Figure 11 It is a schematic diagram of the structure of a first connection part provided by another embodiment of the present application.

[0045] Figure 12 Partial exploded schematic diagram of an insulating member provided by an embodiment of the present application.

[0046] Explanation of reference numerals: 1 - vehicle; 10 - battery device; 20 - battery cell; 30 - controller; 40 - motor; 111 - first part; 112 - second part; 112a - bottom plate; 112b - side plate; 21 - housing; 22 - electrode assembly; 211 - shell; 212 - end cap; 213 - pressure relief mechanism; 222 - tab; 222a - positive tab; 222b - negative tab; 214 - electrode terminal; 214a - positive electrode terminal; 214b - negative electrode terminal; 23 - connecting member; 24 - insulating member; 25 - receiving cavity; 50 - first wall; 510 - first connection part; 520 - second connection part; 521 - first sub - connection part; 510a - second sub - connection part; 510b - third sub - connection part; 511 - first through - hole; 512 - weak area; 610 - first surface; 620 - second surface; 60 - first opening; 70 - second wall; 530 - connection area; 540 - third connection part. Detailed Description of the Invention

[0047] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without making creative efforts fall within the scope of protection of this application.

[0048] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used in this application in the specification are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects and are not used to describe a specific order or primary-secondary relationship.

[0049] Reference to "embodiment" in this application means that a specific feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0050] In the description of this application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "coupled", and "attached" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0051] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally represents an "or" relationship between the associated objects before and after.

[0052] In the embodiments of the present application, the same reference numerals denote the same components, and for the sake of brevity, in different embodiments, the detailed description of the same components is omitted. It should be understood that the thickness, length, width, etc. of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width, etc. of the integrated device are only illustrative and should not constitute any limitation to the present application.

[0053] In the present application, "a plurality of" refers to two or more (including two). Similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of sheets" refers to two or more sheets (including two sheets).

[0054] In the embodiments of the present application, the battery cell may be a secondary battery, which refers to a battery cell that can be activated by charging after discharging so that the active material can be reused. The battery device in the embodiments of the present application may also be referred to as a battery.

[0055] The battery cell may be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-metal hydride battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of the present application are not limited thereto.

[0056] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, which can prevent the short circuit between the positive and negative electrodes and at the same time allow the active ions to pass through.

[0057] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0058] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode active material is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0059] As an example, the positive electrode current collector may be a metal foil, a foam metal, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. may be used. The foam metal may be foam nickel, foam copper, foam aluminum, foam alloy, or foam carbon, etc. The composite current collector may include a polymer material substrate layer and a metal layer. The composite current collector may be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0060] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as the positive electrode active material of the battery may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of the lithium-containing phosphate may include, but are not limited to, lithium iron phosphate (such as LiFePO4 (which may also be abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and at least one of a composite material of lithium manganese iron phosphate and carbon.

[0061] As an example, the positive electrode active material may include at least one of sodium transition metal oxides, polyanion-type compounds, and Prussian blue compounds.

[0062] In some implementations, the sodium transition metal oxide may be a doped and modified sodium transition metal oxide, and the doping modification of the sodium transition metal oxide may include at least one of sodium-site doping modification, oxygen-site doping modification, transition metal-site doping modification, and surface coating modification.

[0063] In some implementations, the positive electrode may employ a foam metal. The foam metal may be foam nickel, foam copper, foam aluminum, foam alloy, or foam carbon, etc. When the foam metal is used as the positive electrode, the positive electrode active material may not be provided on the surface of the foam metal, or of course, the positive electrode active material may be provided. As an example, a lithium source material, potassium metal, or sodium metal may also be filled and / or deposited in the foam metal, and the lithium source material is lithium metal and / or a lithium-rich material.

[0064] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector and a negative electrode active material provided on at least one surface of the negative electrode current collector.

[0065] As an example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode active material is provided on any one or both of the two opposite surfaces of the negative electrode current collector.

[0066] As an example, the negative electrode current collector can be a metal foil, a foam metal, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, titanium, etc. can be used. The composite current collector can include a polymer material substrate layer and a metal layer. The foam metal can be foam nickel, foam copper, foam aluminum, foam alloy, or foam carbon, etc. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as substrates of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0067] In some implementation manners, the battery cell in the embodiments of the present application can be a sodium secondary battery without a negative electrode.

[0068] A sodium secondary battery without a negative electrode refers to a battery cell that does not actively set a negative electrode active material layer on the negative electrode side during the manufacturing process of the battery cell. For example, during the manufacturing process of the battery cell, a sodium metal or carbonaceous active material layer is not formed by processes such as coating or deposition at the negative electrode to form a negative electrode active material layer. During the first charging, sodium ions obtain electrons on the anode side to deposit on the surface of the current collector to form a sodium metal phase. During discharging, metallic sodium can be converted into sodium ions and return to the positive electrode to achieve cyclic charge and discharge. Compared with other sodium secondary batteries, the battery cell of the sodium secondary battery without a negative electrode can obtain a higher energy density because there is no negative electrode active material layer.

[0069] In some implementation manners, in order to improve the performance of the battery cell, some functional coatings, such as carbonaceous materials, metal oxides, alloys, etc., can be provided on the negative electrode side of the sodium secondary battery without a negative electrode to improve the conductivity of the negative electrode current collector and the uniformity of the deposited sodium metal.

[0070] As an example, the negative electrode active material can be a negative electrode active material for battery cells well-known in the art. As an example, the negative electrode active material can include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc.

[0071] In some implementation manners, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0072] In some embodiments, the electrode assembly further includes a separator, and the separator is disposed between the positive electrode and the negative electrode.

[0073] In some embodiments, the separator is a separator membrane. The present application does not particularly limit the type of the separator membrane, and any well-known porous structure separator membrane with good chemical stability and mechanical stability can be selected.

[0074] As an example, the main material of the separator may be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics.

[0075] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode, and simultaneously functions to transport ions and isolate the positive and negative electrodes.

[0076] In some embodiments, the battery cell further includes an electrolyte, which functions to conduct ions between the positive and negative electrodes. There is no specific limitation on the type of the electrolyte in this application, and it can be selected according to requirements. The electrolyte can be liquid, gel-like, or solid.

[0077] In some embodiments, the electrode assembly is provided with tabs, and the tabs can conduct the current out of the electrode assembly. The tabs include a positive tab and a negative tab.

[0078] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum-plastic film, etc. The housing includes a shell body and an end cover.

[0079] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell, or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a multi-prismatic battery, and the multi-prismatic battery is, for example, a hexagonal-prismatic battery, etc.

[0080] To meet different power requirements, the battery device in the embodiments of this application may include a plurality of battery cells. Among them, the plurality of battery cells can be connected in series, in parallel, or in a series-parallel combination. The series-parallel combination refers to a combination of series and parallel connections. In some implementation manners, the plurality of battery cells can first be connected in series, in parallel, or in a series-parallel combination to form a battery module, and then the plurality of battery modules are connected in series, in parallel, or in a series-parallel combination to form a battery. That is to say, the plurality of battery cells can directly form a battery device, or can first form a battery module, and then the battery module forms a battery device. The battery device is further disposed in an electrical device to provide electrical energy for the electrical device.

[0081] In some embodiments, the battery device can be a battery module. When there are a plurality of battery cells, the plurality of battery cells are arranged and fixed to form a battery module.

[0082] In some embodiments, the battery device can be a battery pack, and the battery pack includes a box body and battery cells, and the battery cells or battery modules are accommodated in the box body.

[0083] In some embodiments, the box body can be part of the chassis structure of a vehicle. For example, part of the box body can form at least part of the floor of the vehicle, or part of the box body can form at least part of the cross beams and longitudinal beams of the vehicle.

[0084] In some embodiments, the battery device can be located in an energy storage device. The energy storage device includes an energy storage container, an energy storage electrical cabinet, etc.

[0085] The development of battery technology needs to consider various design factors simultaneously. For example, performance parameters such as energy density, cycle life, discharge capacity, charge-discharge rate, etc. In the development of battery technology, in addition to improving the electrical performance of the battery, safety issues are also a problem that cannot be ignored. If the safety of the battery device cannot be guaranteed, then the battery device cannot be used, reducing the performance of the battery device. Currently, with the increasing demand of consumers for the cruising range of electric vehicles, the capacity and energy density of the battery device have become very important performance indicators. The energy density of the battery device is directly related to the positive and negative electrode materials. High energy density requires cathode active materials with higher Ni content or anode active materials with higher Si content. However, as the content of these elements increases, the safety margin of the battery device also deteriorates. Therefore, how to design the battery cell to achieve directional pressure relief of the battery cell, reduce the risk of thermal runaway diffusion, and improve the performance of the battery device has become an urgent technical problem in this field.

[0086] Therefore, the embodiments of the present application provide a battery cell, a battery device, an electrical device, and an energy storage device. The battery cell includes: a housing, an electrode assembly, a pressure relief mechanism, and an insulating member. The housing includes a receiving cavity; the electrode assembly is received in the receiving cavity; the pressure relief mechanism is disposed on a first wall of the housing; the insulating member is used to wrap at least a part of the surface of the electrode assembly facing the housing, and the insulating member includes a first connecting portion opposite to the first wall; wherein, the melting point of the first connecting portion is less than the melting point of the remaining part of the insulating member other than the first connecting portion. In this way, in the embodiments of the present application, by setting the insulating member to wrap at least a part of the surface of the electrode assembly facing the housing, and the insulating member includes a first connecting portion opposite to the first wall where the pressure relief mechanism is located, and the melting point of the first connecting portion is less than the melting point of the remaining part of the insulating member other than the first connecting portion, in the case of thermal runaway of the battery cell, that is, during the process of increasing the temperature inside the battery cell, the first connecting portion melts earlier than the remaining part of the insulating member other than the first connecting portion, so as to form an exhaust passage communicating with the pressure relief mechanism between the first wall and the surface of the electrode assembly corresponding to the first connecting portion, so that the high-temperature and high-pressure gas generated by the electrode assembly is discharged out of the battery cell through the exhaust passage and the pressure relief mechanism in a directional manner, reducing the risk of damage to the remaining walls of the housing other than the first wall by the high-temperature and high-pressure gas, and at the same time reducing the risk of thermal runaway diffusion, thereby improving the use performance of the battery cell.

[0087] The technical solutions described in the embodiments of the present application are applicable to various electrical devices using battery devices.

[0088] The electrical device can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, etc.; the electric toy includes a fixed or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and a railway electric tool, for example, an electric drill, an electric grinding wheel, an electric wrench, an electric screwdriver, a hammer drill, an impact electric drill, a concrete vibrator, an electric planer, etc. The embodiments of the present application do not impose special restrictions on the above electrical devices.

[0089] It should be understood that the technical solutions described in the embodiments of the present application are not only limited to the above-described electrical devices, but also applicable to all devices using batteries. For the sake of simplicity in the following embodiments, the electrical device is taken as an example of a vehicle for detailed description.

[0090] For example, as Figure 1As shown in the figure, it is a schematic structural diagram of a vehicle 1 according to an embodiment of the present application. The vehicle 1 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A motor 40, a controller 30 and a battery device 10 can be arranged inside the vehicle 1. The controller 30 is used to control the power supply of the battery device 10 to the motor 40. For example, the battery device 10 can be arranged at the bottom, the front end or the rear end of the vehicle 1. The battery device 10 can be used for the power supply of the vehicle 1. For example, the battery device 10 can be used as the operating power supply of the vehicle 1 and used for the circuit system of the vehicle 1, such as the working power consumption requirements for the start, navigation and operation of the vehicle 1. In another embodiment of the present application, the battery device 10 can not only be used as the operating power supply of the vehicle 1, but also be used as the driving power supply of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0091] In order to meet different power usage requirements, the battery device 10 in the embodiment of the present application can include at least one battery cell group. The battery cell group includes a plurality of battery cells. Among them, the plurality of battery cells can be electrically connected in series, in parallel or in a combination of series and parallel (mixed connection) to form the battery device 10, where the mixed connection means a combination of series and parallel. The battery device 10 can also be called a battery pack. For example, a plurality of battery cells can first be combined in series, in parallel or in a combination of series and parallel to form a battery module, and then a plurality of battery modules are combined in series, in parallel or in a combination of series and parallel to form the battery device 10. That is to say, a plurality of battery cells can directly form the battery device 10, or can first form a battery module and then form the battery device 10 by combining the battery modules.

[0092] For example, as Figure 2 shown in the figure, it is a schematic structural diagram of a battery device 10 according to an embodiment of the present application. The battery device 10 can include a plurality of battery cells 20. The battery device 10 can also include a box body 11 (or called a cover body). The inside of the box body 11 is a hollow structure, and a plurality of battery cells 20 are accommodated in the box body 11. For example, a plurality of battery cells 20 are combined in parallel, in series or in a combination of series and parallel and then placed in the box body 11.

[0093] As Figure 2As shown in the figure, the box body 11 can include two parts, which are respectively referred to as the first part 111 and the second part 112 here, and the first part 111 and the second part 112 are snapped together. The shapes of the first part 111 and the second part 112 can be determined according to the shape of the combination of multiple battery cells 20, and the first part 111 and the second part 112 can both have an opening. For example, both the first part 111 and the second part 112 can be hollow cuboids and each has only one face as the opening face. The openings of the first part 111 and the second part 112 are arranged opposite to each other, and the first part 111 and the second part 112 are snapped together to form a box body 11 with a closed chamber. Among them, the box body can include a bottom plate 112a, side plates 112b and beams. Multiple battery cells 20 are placed in the box body 11 formed after the first part 111 and the second part 112 are snapped together after being connected in parallel, series or in a mixed connection.

[0094] Optionally, the battery device 10 can also include other structures, which will not be elaborated one by one here. For example, the battery device 10 can also include a busbar component, and the busbar component is used to realize the electrical connection between multiple battery cells 20, such as in parallel, series or in a mixed connection. Specifically, the busbar component can realize the electrical connection between battery cells 20 by connecting the electrode terminals of the battery cells 20. Further, the busbar component can be fixed to the electrode terminals of the battery cells 20 by welding. The electrical energy of multiple battery cells 20 can be further led out through a conductive mechanism passing through the box body. Optionally, the conductive mechanism can also belong to the busbar component.

[0095] According to different power requirements, the number of battery cells 20 can be set to any value. Multiple battery cells 20 can be connected in series, parallel or in a mixed connection to achieve a larger capacity or power. Since the number of battery cells 20 included in each battery device 10 may be large, for the convenience of installation, the battery cells 20 can be grouped, and each group of battery cells 20 forms a battery module. The number of battery cells 20 included in the battery module is not limited and can be set according to requirements.

[0096] In the embodiments of the present application, according to different power requirements, the number of battery cells 20 can be set to any value. Multiple battery cells 20 can be connected in series, parallel or in a mixed connection to achieve a larger capacity or power. Since the number of battery cells 20 included in each battery device 10 may be large, for the convenience of installation, the battery cells 20 can be grouped, and each group of battery cells 20 forms a battery module. The number of battery cells 20 included in the battery module is not limited and can be set according to requirements. The battery device 10 can include multiple battery modules, and these battery modules can be connected in series, parallel or in a mixed connection.

[0097] Figure 3The schematic structural diagram of a battery cell 20 provided by an embodiment of the present application is shown. Figure 4 The exploded structural schematic diagram of a battery cell 20 provided by another embodiment of the present application is shown. As Figure 3 and Figure 4 shown, the battery cell 20 of the embodiment of the present application may include: a housing 21 and an electrode assembly 22. The housing 21 has a closed accommodation space, and the electrode assembly 22 is placed in the accommodation space inside the housing 21. The housing 21 may include a housing body 211 and an end cap 212. The housing body 211 is a hollow structure with at least one opening; the end cap 212 is used to cooperate with the housing body 211 to form a housing 21 with a closed accommodation space.

[0098] In some embodiments, the end cap 212 may be a plate-like structure for covering the opening of the housing body 211. In other embodiments, the structure of the end cap 212 is similar to that of the housing body 211, that is, both the housing body 211 and the end cap 212 are hollow structures with one opening, and the two openings are docked to form a housing 21 with a closed accommodation space.

[0099] It should be understood that if the end cap 212 is a plate-like structure, the housing body 211 may be a hollow structure with an opening formed at one end or multiple ends. For example, if the housing body 211 is a hollow structure with an opening formed at one end, one end cap 212 may be provided; if the housing body 211 is a hollow structure with openings formed at opposite ends, two end caps 212 may be provided, and the two end caps 212 are respectively used to cover the openings at both ends of the housing body 211.

[0100] The housing 21 may be in various shapes, such as a cylinder, a cuboid, or other polyhedrons. Exemplarily, as Figure 3 and Figure 4 shown, in the embodiment of the present application, the housing 21 is mainly described by taking the cuboid structure as an example.

[0101] It should be understood that the end cap 212 of the embodiment of the present application is used to cooperate with the housing body 211 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the end cap 212 may be adapted to the shape of the housing body 211. As Figure 3 and Figure 4 shown, the housing body 211 is a cuboid structure, and the end cap 212 is a rectangular plate-like structure adapted to the housing body 211.

[0102] In some embodiments, the housing body 211 may be a hollow structure with an opening formed at at least one end, and the shape of the end cap 212 may be adapted to the shape of the housing body 211. The end cap 212 is used to cover the opening of the housing body 211 so that the housing 21 isolates the internal environment of the battery cell 20 from the external environment. If the housing body 211 is a hollow structure with an opening formed at one end, one end cap 212 may be provided.

[0103] The material of the housing 211 in the embodiments of the present application may include one or more types. For example, it may include copper, iron, aluminum, steel, aluminum alloy, etc. The material of the end cap 212 may also be one or more types. For example, it may include copper, iron, aluminum, steel, aluminum alloy, etc. Among them, the material of the end cap 212 may be the same as or different from the material of the housing 211; the materials of different walls of the housing 211 may also be the same or different.

[0104] The end cap 212 in the embodiments of the present application may be any wall of the outer shell 21. For example, the end cap 212 may be the wall with the largest area, the wall with the smallest area, or other walls among the multiple walls included in the outer shell 21. The embodiments of the present application are not limited thereto. Alternatively, the end cap 212 may also be other structures. For example, the end cap 212 may also be a groove structure with an opening to cover the opening of the housing 211 with the opening of the end cap 212. The embodiments of the present application are not limited thereto.

[0105] It should be understood that the battery cell 20 further includes electrode terminals 214. The electrode terminals 214 in the embodiments of the present application are used to electrically connect to the electrode assembly 22 inside the battery cell 20 to output the electrical energy of the battery cell 20. As Figures 3 to 4 shown, the battery cell 20 may include at least two electrode terminals 214. The at least two electrode terminals 214 may include at least one positive electrode terminal 214a and at least one negative electrode terminal 214b. The positive electrode terminal 214a is used to electrically connect to the positive electrode tab 222a of the electrode assembly 22, and the negative electrode terminal 214b is used to electrically connect to the negative electrode tab 222b of the electrode assembly 22. The positive electrode terminal 214a and the positive electrode tab 222a may be directly connected or indirectly connected, and the negative electrode terminal 214b and the negative electrode tab 222b may be directly connected or indirectly connected. Exemplarily, the positive electrode terminal 214a may be electrically connected to the positive electrode tab 222a through a connecting member 23, and the negative electrode terminal 214b is electrically connected to the negative electrode tab 222b through a connecting member 23. It should be understood that in the embodiments of the present application, the positive electrode tab 222a and the negative electrode tab 222b may be collectively referred to as the electrode tab 222.

[0106] In the embodiments of the present application, the walls of the housing 211 and the walls of the end cap 212 are both referred to as the walls of the battery cell 20. Among them, for Figure 3 and Figure 4The cuboid-shaped battery cell 20 shown in the figure has a housing 211 whose walls include a bottom wall and four side walls. The housing 211 is shaped according to the combined shape of one or more electrode assemblies 22. For example, the housing 211 can be a hollow cuboid, cube, or cylinder, and one of the faces of the housing 211 has an opening so that one or more electrode assemblies 22 can be placed inside the housing 211. For example, when the housing 211 is a hollow cuboid or cube, one of the flat surfaces of the housing 211 is the opening surface, that is, this plane does not have a wall body and thus the inside and outside of the housing 211 communicate. When the housing 211 can be a hollow cylinder, the end face of the housing 211 is the opening surface, that is, this end face does not have a wall body and thus the inside and outside of the housing 211 communicate. The end cap 212 covers the opening and is connected to the housing 211 to form a closed cavity for placing the electrode assembly 22. The housing 211 is filled with an electrolyte, such as an electrolytic solution.

[0107] In this battery cell 20, the electrode assembly 22 is the component in the battery cell 20 where the electrochemical reaction occurs. According to actual usage requirements, the number of electrode assemblies 22 inside the housing 211 can be set to one or multiple. For example, as Figure 4 shown, there are 2 electrode assemblies 22 inside the battery cell 20. The electrode assembly 22 can be a cylinder, cuboid, etc. If the electrode assembly 22 has a cylindrical structure, the housing 211 can also have a cylindrical structure. If the electrode assembly 22 has a cuboid structure, the housing 211 can also have a cuboid structure.

[0108] In this battery cell 20, the electrode assembly 22 is the component in the battery cell 20 where the electrochemical reaction occurs. According to actual usage requirements, the number of electrode assemblies 22 inside the housing 211 can be set to one or multiple. For example, as Figure 4 shown, there are 2 electrode assemblies 22 inside the battery cell 20. The electrode assembly 22 can be a cylinder, cuboid, etc. If the electrode assembly 22 has a cylindrical structure, the housing 211 can also have a cylindrical structure. If the electrode assembly 22 has a cuboid structure, the housing 211 can also have a cuboid structure. In the embodiments of the present application, the material of the housing 211 can include the following materials: copper, iron, aluminum, steel, aluminum alloy, etc.

[0109] A pressure relief mechanism 213 can also be provided on the battery cell 20. The pressure relief mechanism 213 is actuated to release the internal pressure or temperature when the internal pressure or temperature of the battery cell 20 reaches a threshold value.

[0110] The pressure relief mechanism 213 can be various possible pressure relief mechanisms 213. For example, the pressure relief mechanism 213 can be a temperature-sensitive pressure relief mechanism, which is configured to melt when the internal temperature of the battery cell 20 provided with the pressure relief mechanism 213 reaches a threshold value; and / or, the pressure relief mechanism 213 can be a pressure-sensitive pressure relief mechanism, which is configured to rupture when the internal air pressure of the battery cell 20 provided with the pressure relief mechanism 213 reaches a threshold value.

[0111] In some implementation manners, an insulating member 24 can also be disposed in the battery cell 20. The insulating member 24 is disposed in the accommodation space of the housing 211, and the insulating member 24 can be a hollow structure with one end or multiple ends formed with openings. The accommodation space inside the hollow structure is used to accommodate the electrode assembly 22 to improve the insulation performance of the battery cell 20.

[0112] Figure 5 The schematic structural diagram of the insulating member 24 provided by an embodiment of the present application is shown. Figure 6 The schematic structural diagram of the insulating member 24 provided by another embodiment of the present application is shown. Figure 7 The schematic structural diagram of the battery cell 20 provided by another embodiment of the present application is shown. Figure 8 The cross-sectional schematic diagram of the battery cell 20 provided by an embodiment of the present application is shown. Figure 9 The cross-sectional schematic diagram of the battery cell 20 provided by another embodiment of the present application is shown. Exemplarily, Figure 8 The cross-sectional schematic diagram shown in Figure 7 can be the cross-sectional schematic diagram of the battery cell 20 shown in Figure 8 The cross-sectional schematic diagram shown in Figure 7 can be the cross-sectional schematic diagram of the battery cell 20 shown in

[0113] It should be understood that in the embodiments of the present application, for the convenience of description, as Figures 7 to 9 shown, the direction X can be the length direction or the width direction of the battery cell 20. The direction X is perpendicular to the direction Z and the direction Y, or the direction X can also be the length direction of the housing 211. In the embodiments of the present application, the direction X can be the third direction; the direction Y can be the width direction of the battery cell 20. The direction Y is perpendicular to the direction Z and the direction X. In the embodiments of the present application, the direction Y can be the second direction; the direction Z can be the height direction of the battery cell 20. The direction Z is perpendicular to the direction X and the direction Y, or the direction Z can also be the height direction of the housing 211. Exemplarily, when the direction X is the length direction of the housing 211, the direction Y is the width direction of the housing 211.

[0114] In some implementation manners, as Figures 5 to 9As shown, the battery cell 20 includes: a housing 211, an electrode assembly 22, a pressure relief mechanism 213, and an insulating member 24. The housing 211 includes a receiving cavity 25. The electrode assembly 22 is received in the receiving cavity 25. The pressure relief mechanism 213 is disposed on a first wall 50 of the housing 211. The insulating member 24 is configured to wrap at least a portion of a surface of the electrode assembly 22 facing the housing 211. The insulating member 24 includes a first connecting portion 510 opposite to the first wall 50. Wherein, the melting point of the first connecting portion 510 is less than the melting point of the remaining portion of the insulating member 24 other than the first connecting portion 510.

[0115] It should be understood that the housing 211 of the battery cell 20 according to the embodiments of the present application may be a polyhedral structure of any shape, that is, the housing 211 may include a plurality of walls. The first wall 50 is any one of the walls of the housing 211, that is, the pressure relief mechanism 213 may be located on any one of the walls of the housing 211.

[0116] Exemplarily, in some implementation manners, the first wall 50 includes but is not limited to the following examples: the first wall 50 may be the wall with the smallest area of the housing 211; the first wall 50 may be the wall of the battery cell 20 provided with the pressure relief mechanism 213; the first wall 50 may be the wall adjacent to the wall of the battery cell 20 provided with the electrode terminal 214; the first wall may be the wall opposite to the wall of the battery cell 20 provided with the electrode terminal 214.

[0117] It should also be understood that the receiving cavity 25 included in the housing 211 may be an open receiving cavity or a closed receiving cavity. For example, in the case where the receiving cavity 25 is an open receiving cavity, at least one opening may be provided at an end of the receiving cavity 25, and the opening is used for sealing connection with an end cap 212.

[0118] It should also be understood that the insulating member 24 in the embodiments of the present application is configured to wrap at least a portion of a surface of the electrode assembly 22 facing the housing 211, which may mean that the insulating member 24 can wrap a portion or all of the surface of the electrode assembly 22 facing the housing 211 without affecting the use performance of the electrode assembly 22, so as to reduce the risk of short circuit of the battery device 10 caused by direct contact between the electrode assembly 22 and the housing 211.

[0119] It should also be understood that as Figure 5 and Figure 6 shown, schematic structural diagrams of two different insulating members 24 before wrapping the electrode assembly 22 or in an unused state are respectively shown. Exemplarily, the Figure 5The insulating member 24 shown therein includes a first connecting portion 510 which is fixedly connected to an edge region of another portion of the insulating member 24, such as a second connecting portion 520, after being bent and formed. Exemplarily, the first connecting portion 510 can be adhesively connected or heat-melt connected to the edge region of the second connecting portion 520, that is, the surface of the first connecting portion 510 close to the second connecting portion 520 can be heat-melt connected to the surface of the first sub-connecting portion 521 close to the first connecting portion 510. Figure 6 The first connecting portion 510 in the insulating member 24 shown therein includes two sub-connecting portions, namely a second sub-connecting portion 510a and a third sub-connecting portion 510b. After the insulating member 24 is subjected to a bending and forming process, at least a part of the second sub-connecting portion 510a and the third sub-connecting portion 510b are stacked in a plane perpendicular to the thickness direction of the first connecting portion 510. That is, in a plane perpendicular to the thickness direction of the first connecting portion 510, the orthographic projections of the second sub-connecting portion 510a and the third sub-connecting portion 510b can completely overlap or partially overlap, and the second sub-connecting portion 510a and the third sub-connecting portion 510b can be adhesively connected or heat-melt connected.

[0120] It should also be understood that the pressure relief mechanism 213 in the embodiments of the present application refers to an element or component that is actuated when the internal pressure or temperature of the battery cell 20 reaches a predetermined threshold to release the internal pressure or temperature. The threshold design varies according to different design requirements. The threshold may depend on one or several materials among the positive electrode plate, negative electrode plate, electrolyte, and separator membrane in the battery cell 20.

[0121] The "actuation" mentioned in the present application means that the pressure relief mechanism 213 generates an action or is activated to a certain state, so that the internal pressure and temperature of the battery cell 20 can be released. The actions generated by the pressure relief mechanism 213 may include, but are not limited to: at least a part of the pressure relief mechanism 213 rupturing, breaking, being torn, or opening, etc. During the actuation process of the pressure relief mechanism 213, the high-temperature and high-pressure substances inside the battery cell 20 will be discharged outward from the actuated part as emissions. In this way, the battery cell 20 can be depressurized and de-temperatureed under controllable pressure or temperature, thereby avoiding potential more serious accidents.

[0122] The emissions from the battery cell 20 mentioned in the embodiments of the present application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of the insulating member 24, high-temperature and high-pressure gases generated by reactions, flames, etc.

[0123] Exemplarily, the pressure relief mechanism 213 may be disposed on the bottom wall of the battery cell 20. For example, the pressure relief mechanism may be disposed on the bottom wall of the housing 211. The pressure relief mechanism 213 may be various possible pressure relief mechanisms 213. For example, the pressure relief mechanism 213 may be a temperature-sensitive pressure relief mechanism configured to melt when the internal temperature of the battery cell 20 provided with the pressure relief mechanism 213 reaches a threshold; and / or, the pressure relief mechanism 213 may be a pressure-sensitive pressure relief mechanism configured to rupture when the internal air pressure of the battery cell 20 provided with the pressure relief mechanism 213 reaches a threshold.

[0124] It should also be understood that in the embodiments of the present application, the insulating member 24 may be formed by split molding. During the process of wrapping the insulating member 24 around the electrode assembly 22, a connection area needs to be reserved in the area close to the first connection portion 510 of the remaining connection portions connected to the first connection portion 510. The first connection portion 510 is thermally connected to the remaining connection portions through the connection area, and then the insulating member 24 after the thermal connection is bent and formed to wrap the surface of the electrode assembly 22 facing the housing 211, and the wrapped first connection portion 510 is disposed opposite to the first wall 50.

[0125] It should also be understood that in some implementation manners, as Figure 5 shown, the insulating member 24 may include a first connection portion 510, a second connection portion 520, and a third connection portion 540. Among them, the first connection portion 510 and the second connection portion 520 are thermally connected, the third connection portion 540 is disposed between the two second connection portions 520, and the third connection portion 540 may be integrally formed or split formed with the two second connection portions 520. For example, in the case where the third connection portion 540 is split formed with the two second connection portions 520, the edge regions of the third connection portion 540 close to the two second connection portions 520 are thermally connected to the two second connection portions 520.

[0126] In an embodiment of the present application, by arranging the insulating member 24 to wrap at least a part of the surface of the electrode assembly 22 facing the housing 211, and the insulating member 24 includes a first connecting portion 510 opposite to the first wall 50 where the pressure relief mechanism 213 is located, and the melting point of the first connecting portion 510 is less than that of the remaining part of the insulating member 24 except the first connecting portion 510. In the case of thermal runaway of the battery cell 20, that is, during the process of the temperature rising inside the battery cell 20, the first connecting portion 510 melts earlier than the remaining part of the insulating member 24 except the first connecting portion 510, so as to form an exhaust passage communicating with the pressure relief mechanism 213 between the first wall 50 and the surface of the electrode assembly 22 corresponding to the first connecting portion 510, enabling the high-temperature and high-pressure gas generated by the electrode assembly 22 to be discharged out of the battery cell 20 through the exhaust passage and the pressure relief mechanism 213 in a directed manner, reducing the risk of damage to the remaining walls of the housing 211 except the first wall 50 by the high-temperature and high-pressure gas, and at the same time reducing the risk of thermal runaway spreading, thereby improving the service performance of the battery cell 20.

[0127] In some implementation manners, as Figures 5 to 9 shown, the insulating member 24 further includes a second connecting portion 520 connected to the first connecting portion 510. The first connecting portion 510 is used to cover the first surface 610 of the electrode assembly 22, and the second connecting portion 520 is used to cover the second surface 620 of the electrode assembly 22. The area of the second surface 620 is larger than the area of the first surface 610.

[0128] It should be understood that in the case of thermal runaway of the battery cell 20, due to the lower melting point of the first connecting portion 510, the first connecting portion 510 melts preferentially compared with the second connecting portion 520, and the second connecting portion 520 slowly melts or does not melt during the whole thermal runaway process, so that the second surface 620 of the electrode assembly 22 does not come into contact with the housing 211, reducing the risk of short circuit caused by direct contact between the second surface 620 of the electrode assembly 22 and the housing 211.

[0129] It should also be understood that the first connecting portion 510 is used to cover the first surface 610 of the electrode assembly 22, which may mean that in a plane perpendicular to the thickness direction of the first connecting portion 510, the projected area of the first connecting portion 510 is greater than or equal to the projected area of the first surface 610 of the electrode assembly 22. The second connecting portion 520 is used to cover the second surface 620 of the electrode assembly 22, which may mean that in a plane perpendicular to the thickness direction of the second connecting portion 520, the projected area of the second connecting portion 520 is greater than or equal to the projected area of the second surface 620 of the electrode assembly 22.

[0130] In an embodiment of the present application, by setting the insulating member 24 to include a second connecting portion 520 connected to the first connecting portion 510, and the first connecting portion 510 is used to cover the first surface 610 of the electrode assembly 22, the second connecting portion 520 is used to cover the second surface 620 of the electrode assembly 22, and the area of the second surface 620 is larger than the area of the first surface 610. In the case of thermal runaway of the battery cell 20, the first connecting portion 510 melts earlier than the second connecting portion 520, so as to form an exhaust passage communicating with the pressure relief mechanism 213 between the first wall 50 and the first surface 610, enabling the high-temperature and high-pressure gas generated by the electrode assembly 22 to be discharged out of the battery cell 20 through the exhaust passage and the pressure relief mechanism 213 in a directional manner, reducing the risk of damage to the wall of the housing 211 opposite to the second surface 620 by the high-temperature and high-pressure gas, that is, reducing the risk of short circuit of the battery cell 20 caused by direct contact between the second surface 620 and the surface of the housing 211, and at the same time reducing the risk of thermal runaway diffusion, thereby improving the performance of the battery cell 20.

[0131] In some implementation manners, the melting point T1 of the first connecting portion 510 and the melting point T2 of the second connecting portion 520 satisfy: T2 / T1≥1.5. In this way, in an embodiment of the present application, by setting the melting point T1 of the first connecting portion 510 and the melting point T2 of the second connecting portion 520 to: T2 / T1≥1.5, in the case of thermal runaway of the battery cell 20, the first connecting portion 510 can melt preferentially compared with the second connecting portion 520, so as to form an exhaust passage communicating with the pressure relief mechanism 213 between the first wall 50 and the first surface 610, enabling the high-temperature and high-pressure gas generated by the electrode assembly 22 to be discharged out of the battery cell 20 through the exhaust passage and the pressure relief mechanism 213 in a directional manner, reducing the risk of thermal runaway diffusion, thereby improving the performance of the battery cell 20.

[0132] In other implementation manners, the melting point T1 of the first connecting portion 510 and the melting point T2 of the second connecting portion 520 further satisfy: T2 / T1≥2.

[0133] Figure 10 The structural schematic diagram of the first connecting portion 510 provided by an embodiment of the present application is shown.

[0134] In some implementation manners, the first connecting portion 510 is provided with a first through hole 511 penetrating through the first connecting portion 510 along the thickness direction of the first connecting portion 510, and the first through hole 511 communicates with the accommodating cavity 25.

[0135] It should be understood that the shape of the above-mentioned first through-hole 511 can be set according to actual needs. For example, in a plane perpendicular to the thickness direction of the first connecting portion 510, the shape of the first through-hole 511 can be circular, elliptical, polygonal, rectangular, etc. It should also be understood that the aperture size of the first through-hole 511 can be set according to actual needs. As an example, the embodiments of the present application do not limit this.

[0136] In the embodiments of the present application, by providing a first through-hole 511 on the first connecting portion 510 that penetrates the first connecting portion 510 along the thickness direction of the first connecting portion 510, the first through-hole 511 communicates with the accommodation cavity 25. In the case of thermal runaway of the battery cell 20, the first connecting portion 510 can be quickly melted to form an exhaust passage communicating with the pressure relief mechanism 213 between the first wall 50 and the first surface 610, so that the high-temperature and high-pressure gas generated by the electrode assembly 22 can be directed and quickly discharged to the outside of the battery cell 20 through the exhaust passage and the pressure relief mechanism 213, reducing the risk of thermal runaway diffusion, thereby improving the service performance of the battery cell 20.

[0137] In some implementation manners, a plurality of the first through-holes 511 are provided on the first connecting portion 510, and the plurality of first through-holes 511 are arranged at intervals along a first direction, and the first direction is perpendicular to the thickness direction of the first connecting portion 510.

[0138] It should be understood that in the embodiments of the present application, a plurality of the first connecting portions 510 can be arranged at equal intervals or unequal intervals along the first direction. Specifically, in the first direction, the distance between any two adjacent first connecting portions 510 among the plurality of first connecting portions 510 can be set according to actual needs. As an example, the embodiments of the present application do not limit this.

[0139] In the embodiments of the present application, by providing a plurality of the first through-holes 511 on the connecting portion 510, and the plurality of first through-holes 511 are arranged at intervals along the first direction, and the first direction is perpendicular to the thickness direction of the first connecting portion 510. In the case of thermal runaway of the battery cell 20, the melting of the first connecting portion 510 can be further accelerated to form an exhaust passage communicating with the pressure relief mechanism 213 between the first wall 50 and the first surface 610, so that the high-temperature and high-pressure gas generated by the electrode assembly 22 can be directed and quickly discharged to the outside of the battery cell 20 through the exhaust passage and the pressure relief mechanism 213, reducing the risk of thermal runaway diffusion, thereby improving the service performance of the battery cell 20.

[0140] Figure 11 The structural schematic diagram of the first connecting portion 510 provided by another embodiment of the present application is shown.

[0141] In some implementation manners, such asFigure 11 As shown, the first connecting portion 510 is provided with a weak area 512, and the weak area 512 is configured to melt when the temperature in the accommodation cavity 25 reaches a threshold value, so as to form an exhaust passage communicating with the pressure relief mechanism 213 between the first surface 610 and the first wall 50.

[0142] It should be understood that the above temperature threshold can be set according to actual needs. For example, when the temperature in the accommodation cavity 25 reaches the threshold value, the weak area 512 on the first connecting portion 510 preferentially melts, and an exhaust passage communicating with the pressure relief mechanism 213 is formed between the first surface 610 and the first wall 50, so that the high-temperature and high-pressure gas generated by the electrode assembly 22 is discharged to the outside of the battery cell 20 through the exhaust passage and the pressure relief mechanism 213 in a directional and rapid manner, reducing the risk of thermal runaway diffusion.

[0143] In the embodiment of the present application, by providing a weak area 512 on the first connecting portion 510, and the weak area 512 is configured to melt when the temperature in the accommodation cavity 25 reaches a threshold value, so as to form an exhaust passage communicating with the pressure relief mechanism 213 between the first surface 610 and the first wall 50, so that the high-temperature and high-pressure gas generated by the electrode assembly 22 is discharged to the outside of the battery cell 20 through the exhaust passage and the pressure relief mechanism 213 in a directional and rapid manner, reducing the risk of thermal runaway diffusion, thereby improving the use performance of the battery cell 20. At the same time, when thermal runaway does not occur, the setting of the weak area 512 can also reduce the risk of short circuit caused by direct contact between the housing 211 and the electrode assembly 22.

[0144] In some implementation manners, the thickness of the weak area 512 is smaller than the thickness of the remaining area of the first connecting portion 510 except the weak area, and / or, the weak area 512 is provided with a notch on the surface perpendicular to the thickness direction of the first connecting portion 510.

[0145] It should be understood that in the embodiment of the present application, the shape of the above weak area 512 can be set according to actual needs. Exemplarily, the shape of the weak area 512 includes but is not limited to a circle, an ellipse, a rectangle, and a regular polygon. As an example, the embodiment of the present application does not limit this.

[0146] It should also be understood that the number of the weak areas 512 provided on the area of the first connecting portion 510 corresponding to the first wall 50 can be set according to actual needs. For example, the number of the weak areas 512 can be one or more.

[0147] It should also be understood that the thickness of the weak area 512 can also be set to be less than the thickness of the remaining part of the first connecting portion 510. Since the weak area 512 is thinner than the remaining part of the first connecting portion 510, the weak area 512 preferentially melts when the temperature in the accommodation cavity 25 reaches the threshold. It should also be understood that in the embodiments of the present application, the shape of the notch provided on the surface of the weak area 512 in the thickness direction perpendicular to the first connecting portion 510 can be set according to actual needs. Exemplarily, the notch includes but is not limited to a cross notch, a rice-shaped notch, and an I-shaped notch.

[0148] In the embodiments of the present application, by setting the thickness of the weak area 512 to be less than the thickness of the remaining area of the first connecting portion 510 other than the weak area 512, and / or by providing a notch on the surface of the weak area 512 in the thickness direction perpendicular to the first connecting portion 510, when the battery cell 20 undergoes thermal runaway, melting preferentially occurs at the weak area 512 of the first connecting portion 510, and further accelerates the melting of the first connecting portion 510, so as to form an exhaust passage communicating with the pressure relief mechanism 213 between the first wall 50 and the first surface 610, enabling the high-temperature and high-pressure gas generated by the electrode assembly 22 to be discharged to the outside of the battery cell 20 through the exhaust passage and the pressure relief mechanism 213 in a directional and rapid manner, reducing the risk of thermal runaway diffusion, thereby improving the performance of the battery cell 20. At the same time, the implementation manner of the weak area 512 is simple, easy to process and manufacture, and reduces the manufacturing cost.

[0149] In some implementation manners, such as Figures 7 to 9 shown, the electrode assembly 22 is provided with a tab 222, and the tab 222 faces the second wall 70 of the battery cell 20, and the second wall 70 is different from the first wall 50. In this way, in the embodiments of the present application, by setting the tab 222 of the electrode assembly 22 to face the second wall 70 of the battery cell 20 to be different from the first wall 50, when the battery cell 20 undergoes thermal runaway, an exhaust passage communicating with the pressure relief mechanism 213 can be formed between the first wall 50 and the first surface 610, enabling the high-temperature and high-pressure gas generated by the electrode assembly 22 to be discharged to the outside of the battery cell 20 through the exhaust passage and the pressure relief mechanism 213 in a directional and rapid manner, reducing the risk of damage to the tab 222 during the pressure relief process, and reducing the risk of thermal runaway diffusion, thereby improving the performance of the battery cell 20.

[0150] In some implementation manners, such as Figure 8 and Figure 9 shown, the electrode assembly 22 includes two tabs 222 arranged oppositely, and the two tabs 222 respectively face the two second walls 70 of the battery cell 20 arranged oppositely, and the first wall 50 connects the two second walls 70.

[0151] In the embodiment of the present application, by arranging the electrode assembly 22 to include two of the tab ears 222 arranged oppositely, and the two tab ears 222 respectively face two of the second walls 70 arranged oppositely of the battery cell 20, and the first wall 50 connects the two second walls 70. In the case of thermal runaway of the battery cell 20, an exhaust passage communicating with the pressure relief mechanism 213 can be formed between the first wall 50 and the first surface 610, so that the high-temperature and high-pressure gas generated by the electrode assembly 22 is discharged to the outside of the battery cell 20 through the exhaust passage and the pressure relief mechanism 213 in a directional and rapid manner, reducing the risk of damage to the two tab ears 222 during the pressure relief process, and reducing the risk of thermal runaway spreading, thereby improving the service performance of the battery cell 20.

[0152] In some implementation manners, such as Figure 4 、 Figure 7 and Figure 9 shown, the housing 211 includes two first openings 60 arranged oppositely, the battery cell 20 includes two end caps 212 arranged oppositely, the two end caps 212 are respectively used to cover the two first openings 60, and the end cap 212 is the second wall 70.

[0153] In the embodiment of the present application, by arranging the housing 211 to include two first openings 60 arranged oppositely, the battery cell 20 includes two end caps 212 arranged oppositely, the two end caps 212 are respectively used to cover the two first openings 60, and the end cap 212 is the second wall 70. In the case of thermal runaway of the battery cell 20, an exhaust passage communicating with the pressure relief mechanism 213 can be formed between the first wall 50 and the first surface 610, so that the high-temperature and high-pressure gas generated by the electrode assembly 22 is discharged to the outside of the battery cell 20 through the exhaust passage and the pressure relief mechanism 213 in a directional and rapid manner, reducing the risk of damage to the two tab ears 222 and the end cap 212 during the pressure relief process, and reducing the risk of thermal runaway spreading, thereby improving the service performance of the battery cell 20.

[0154] Figure 12 Shows a partial exploded structural schematic diagram of an insulating member 24 provided in an embodiment of the present application.

[0155] In some implementation manners, such as Figure 12 shown, a connection area 530 is provided on the surface of the second connection portion 520 close to the first connection portion 510, the first connection portion 510 is fixedly connected to the connection area 530, and in a plane perpendicular to the thickness direction of the first connection portion 510, at least a part of the orthographic projection of the first connection portion 510 covers the orthographic projection of the connection area 530.

[0156] It should be understood that in the embodiments of the present application, on a plane perpendicular to the thickness direction of the first connecting portion 510, at least a part of the orthographic projection of the first connecting portion 510 covering the orthographic projection of the connecting region 530 may mean that the area of at least a part of the orthographic projection of the first connecting portion 510 is greater than or equal to the area of the orthographic projection of the connecting region 530. It should also be understood that the fixed connection between the first connecting portion 510 and the connecting region 530 may mean that there is a thermal fusion connection or a bonding connection between at least a part of the surface of the first connecting portion 510 facing the connecting region 530 and the surface of the connecting region 530 facing the first connecting portion 510. When the first connecting portion 510 is fixedly connected to the second connecting portion 520, the first connecting portion 510 is bent and formed relative to the second connecting portion 520 to wrap at least a part of the surface of the electrode assembly 22 facing the housing 211.

[0157] In the embodiments of the present application, by setting the first connecting portion 510 to be fixedly connected to the connecting region 530, and on a plane perpendicular to the thickness direction of the first connecting portion 510, at least a part of the orthographic projection of the first connecting portion 510 covers the orthographic projection of the connecting region 530, it is convenient for the fixed connection between the first connecting portion 510 and the second connecting portion 520, and this connection method is simple and feasible, which can effectively improve the processing and manufacturing efficiency of the insulating member 24 and reduce the manufacturing cost.

[0158] In some implementation manners, the first connecting portion 510 is a double-layer structure with at least partial overlap, and the double-layer structure is stacked along the thickness direction of the first connecting portion 510.

[0159] Exemplarily, the first connecting portion 510 being a double-layer structure with at least partial overlap may mean that the first connecting portion 510 is formed by Figure 6 the insulating member 24 shown in being bent. That is, the first connecting portion 510 may be formed by laminating two connecting portions, such as Figure 6 the second sub-connecting portion 510a and the third connecting portion 510b shown in, and the second sub-connecting portion 510a and the third connecting portion 510b may completely overlap or partially overlap. In the case where the second sub-connecting portion 510a and the third connecting portion 510b partially overlap, the overlapping region is disposed opposite to the first wall 50, and the first connecting portion 510 after overlapping arrangement can provide a larger thickness to form an exhaust passage with a larger space communicating with the pressure relief mechanism 213 between the first wall 50 of the housing 211 and the first surface 610 when the battery cell 20 undergoes thermal runaway.

[0160] In an embodiment of the present application, by setting the first connecting portion 510 as a double-layer structure that at least partially overlaps, and the double-layer structure is stacked along the thickness direction of the first connecting portion 510, in the case of thermal runaway of the battery cell 20, it is convenient to form an exhaust passage with a relatively large space communicating with the pressure relief mechanism 213 between the first wall 50 and the first surface 610, so that the high-temperature and high-pressure gas generated by the electrode assembly 22 is discharged to the outside of the battery cell 20 through the exhaust passage and the pressure relief mechanism 213 in a directional and rapid manner, and the risk of thermal runaway diffusion is effectively reduced, thereby improving the service performance of the battery cell 20.

[0161] In some implementation manners, such as Figure 8 and Figure 9 shown, the thickness D1 of the first connecting portion 510 satisfies: 0.1 mm ≤ D1 ≤ 5 mm.

[0162] Exemplarily, the thickness D1 of the first connecting portion 510 can be set to: 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, etc., or its value is within the range obtained by combining any two of the above values.

[0163] In an embodiment of the present application, by setting the thickness D1 of the first connecting portion 510 to be greater than or equal to 0.1 mm and less than or equal to 5 mm, in the case of thermal runaway of the battery cell 20, it is convenient to form an exhaust passage with sufficient space communicating with the pressure relief mechanism 213 between the first wall 50 and the first surface 610, so that the high-temperature and high-pressure gas generated by the electrode assembly 22 is discharged to the outside of the battery cell 20 through the exhaust passage and the pressure relief mechanism 213 in a directional and rapid manner, and the risk of thermal runaway diffusion is effectively reduced, thereby improving the service performance of the battery cell 20, while taking into account the structural strength of the insulating member 24 and the energy density of the battery cell 20.

[0164] In other implementation manners, the thickness D1 of the first connecting portion 510 satisfies: 1 mm ≤ D1 ≤ 3 mm.

[0165] In some implementation manners, such as Figure 9 shown, the thickness D2 of the second connecting portion 520 satisfies: 0.05 mm ≤ D2 ≤ 0.5 mm.

[0166] Exemplarily, the thickness D2 of the second connecting portion 520 can be set to: 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, etc., or its value is within the range obtained by combining any two of the above values.

[0167] In the embodiment of the present application, by setting the thickness D2 of the second connecting portion to be greater than or equal to 0.05 mm and less than or equal to 0.5 mm, the structural strength of the insulating member 24 and the energy density of the battery cell 20 are taken into account.

[0168] In some other implementation manners, the thickness D2 of the second connecting portion 520 satisfies: 0.08 mm ≤ D2 ≤ 0.2 mm.

[0169] Refer to the above again Figures 5 to 12 As shown above, a battery cell 20 is provided. The battery cell 20 includes: a housing 211, an electrode assembly 22, a pressure relief mechanism 213, and an insulating member 24. The housing 211 includes a receiving cavity 25. The electrode assembly 22 is received in the receiving cavity 25. The pressure relief mechanism 213 is disposed on the first wall 50 of the housing 211. The insulating member 24 is used to wrap at least a part of the surface of the electrode assembly 22 facing the housing 211. The insulating member 24 includes a first connecting portion 510 opposite to the first wall 50. Among them, the melting point of the first connecting portion 510 is less than the melting point of the remaining part of the insulating member 24 except the first connecting portion 510. The insulating member 24 further includes a second connecting portion 520 connected to the first connecting portion 510. The first connecting portion 510 is used to cover the first surface 610 of the electrode assembly 22. The second connecting portion 520 is used to cover the second surface 620 of the electrode assembly 22. The area of the second surface 620 is greater than the area of the first surface 610. The melting point T1 of the first connecting portion 510 and the melting point T2 of the second connecting portion 520 satisfy: T2 / T1 ≥ 1.5. The first connecting portion 510 is provided with a first through hole 511 penetrating the first connecting portion 510 along the thickness direction of the first connecting portion 510. The first through hole 511 communicates with the receiving cavity 25.

[0170] The embodiment of the present application further provides a battery device 10, including a plurality of battery cells 20, and the battery cell 20 is the battery cell 20 in any of the above embodiments.

[0171] The embodiment of the present application further provides an electrical device, including the battery device 10 in any of the above embodiments. The battery device 10 is used to provide electrical energy for the electrical device. Specifically, the electrical device may be the Figure 1 vehicle 1 shown above, or any electrical device using the battery device 10.

[0172] The embodiment of the present application further provides an energy storage device, including the battery device 10 in any of the above embodiments. The battery device 10 is used to store electrical energy for the energy storage device.

[0173] Although the present application has been described with reference to the above embodiments, various modifications can be made thereto and components thereof can be replaced with equivalents without departing from the scope of the embodiments of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each of the embodiments can be combined in any manner. The present 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, characterized in that, Comprising: A housing (211), including a receiving cavity (25); An electrode assembly (22), received in the receiving cavity (25); A pressure relief mechanism (213), the pressure relief mechanism (213) being provided on a first wall (50) of the housing (211); An insulating member (24), configured to wrap at least a part of a surface of the electrode assembly (22) facing the housing (211), the insulating member (24) including a first connecting portion (510) opposite to the first wall (50); Wherein, the melting point of the first connecting portion (510) is less than the melting point of the remaining portion of the insulating member (24) other than the first connecting portion (510).

2. The battery cell according to claim 1, characterized in that, The insulating member (24) further includes a second connecting portion (520) connected to the first connecting portion (510), the first connecting portion (510) being configured to cover a first surface (610) of the electrode assembly (22), the second connecting portion (520) being configured to cover a second surface (620) of the electrode assembly (22), and the area of the second surface (620) is larger than the area of the first surface (610).

3. The battery cell according to claim 2, characterized in that, The melting point T1 of the first connecting portion (510) and the melting point T2 of the second connecting portion (520) satisfy: T2 / T1≥1.

5.

4. The battery cell according to claim 2, wherein The first connecting portion (510) is provided with a first through hole (511) penetrating the first connecting portion (510) along the thickness direction of the first connecting portion (510), and the first through hole (511) communicates with the receiving cavity (25).

5. The battery cell according to claim 4, characterized in that, The first connecting portion (510) is provided with a plurality of the first through holes (511), and the plurality of the first through holes (511) are arranged at intervals in a first direction, and the first direction is perpendicular to the thickness direction of the first connecting portion (510).

6. The battery cell according to claim 2, wherein The first connecting portion (510) is provided with a weak area (512), and the weak area (512) is configured to melt when the temperature in the receiving cavity (25) reaches a threshold value, so as to form an exhaust passage communicating with the pressure relief mechanism (213) between the first surface (610) and the first wall (50).

7. The battery cell according to claim 6, characterized in that, The thickness of the weak area (512) is less than the thickness of the remaining area of the first connecting portion (510) other than the weak area (512), and / or, the weak area (512) is provided with a notch on a surface perpendicular to the thickness direction of the first connecting portion (510).

8. The battery cell according to claim 2, wherein, The electrode assembly (22) is provided with a tab (222), and the tab (222) faces a second wall (70) of the battery cell, and the second wall (70) is different from the first wall (50).

9. The battery cell according to claim 8, wherein, The electrode assembly (22) includes two of the tabs (222) arranged oppositely, and the two tabs (222) respectively face two of the second walls (70) of the battery cell arranged oppositely, and the first wall (50) connects the two second walls (70).

10. The battery cell according to claim 9, characterized in that, The housing (211) includes two first openings (60) arranged oppositely, the battery cell includes two end caps (212) arranged oppositely, the two end caps (212) respectively cover the two first openings (60), and the end cap (212) is the second wall (70).

11. The battery cell according to claim 2, wherein A connection area (530) is provided on a surface of the second connection part (520) on a side close to the first connection part (510), the first connection part (510) is fixedly connected to the connection area (530), and at least a part of the orthographic projection of the first connection part (510) covers the orthographic projection of the connection area (530) on a plane perpendicular to the thickness direction of the first connection part (510).

12. The battery cell according to any one of claims 1 to 11, characterized in that, The first connection part (510) is a double-layer structure with at least partial overlap, and the double-layer structure is stacked along the thickness direction of the first connection part.

13. The battery cell according to any one of claims 2 to 11, characterized in that, The thickness D1 of the first connection part (510) satisfies: 0.1 mm ≤ D1 ≤ 5 mm.

14. The battery cell according to any one of claims 2 to 11, characterized in that, The thickness D2 of the second connection part (520) satisfies: 0.05 mm ≤ D2 ≤ 0.5 mm.

15. A battery device, characterized in that, Comprising: A plurality of battery cells, the battery cells being the battery cells according to any one of claims 1 to 14.

16. An electrical device, characterized in that, Comprising: The battery device according to claim 15, the battery device being configured to supply electric energy to the electrical equipment.

17. An energy storage device, characterized in that, Comprising: The battery device according to claim 15, the battery device being configured to store electric energy for the energy storage device.

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