Battery monomer, battery device and electric equipment

Abstract

The utility model is suitable for the technical field of batteries, and provides a battery monomer, a battery device and electric equipment. Each battery monomer comprises a shell, a pressure relief mechanism and a protection plate; the shell comprises a first wall, a second wall and an enclosure bulkhead, the first wall and the second wall are oppositely arranged, and the enclosure bulkhead is connected between the first wall and the second wall; the pressure relief mechanism is arranged on the first wall; the protection plate comprises a first part covering the outer side of the first wall and a second part covering the outer side of at least part of the surrounding wall, and a first receding hole used for exposing the pressure relief mechanism is formed in the first part. According to the technical scheme provided by the embodiment of the invention, the safety of the battery monomer can be improved.

Description

Technical Field

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

[0002] A battery cell is the smallest unit that makes up a battery device. When a battery cell experiences thermal runaway, it will produce uncontrolled ejecta, which will impact the outer shell of the battery cell and may cause the outer shell to melt and break, posing certain safety hazards. Utility Model Content

[0003] In view of this, the embodiments of the present application provide a battery cell, a battery device and an electrical equipment, which can improve the safety of the battery cell.

[0004] An embodiment of the first aspect of the present application provides a battery cell, comprising: an outer shell, comprising a first wall, a second wall and a surrounding wall, the first wall and the second wall are arranged opposite to each other, and the surrounding wall is connected between the first wall and the second wall; a pressure relief mechanism is arranged on the first wall; a protective plate, comprising a first part covering the outer side of the first wall and a second part covering the outer side of at least part of the surrounding wall, and the first part is provided with a first avoidance hole for exposing the pressure relief mechanism.

[0005] In the battery cell provided by the embodiment of the present application, the first part of the protective plate can provide reliable mechanical support for the first wall, and the second part can provide reliable mechanical support for the part of the surrounding wall close to the first wall, so that the risk of deformation and rupture of the non-pressure relief area of ​​the first wall and the surrounding wall due to impact can be reduced by setting the protective plate. At the same time, the protective plate can form an additional physical barrier on the outside of the first wall and at least part of the surrounding wall, reducing the risk of leakage gaps in the non-pressure relief area of ​​the first wall and the surrounding wall due to high temperature melting, so that the safety of the battery cell is effectively improved by setting the protective plate. In addition, a first avoidance hole is provided on the first part of the protective plate, so that the pressure relief mechanism can be directly exposed to the outside, ensuring that the pressure relief mechanism can be used normally without being hindered by the protective plate.

[0006] In some embodiments, along the normal direction of the first wall, the orthographic projection area of ​​the first portion is S1, the orthographic projection area of ​​the pressure relief mechanism is S2, and 1.5≤S1 / S2≤7.

[0007] In the above design, by reasonably limiting the ratio range of S1 and S2, normal heat dissipation of the battery cell can be ensured, while the use effect of the protective plate can be improved.

[0008] In some embodiments, 400 mm 2 ≤S1≤8500mm 2 , and / or 300mm 2 ≤S2≤1400mm 2 .

[0009] In the above design, the size range of the first part of the protective plate and the pressure relief mechanism is further limited, so that the design of the protective plate and the pressure relief mechanism is more reasonable.

[0010] In some embodiments, the pressure relief mechanism is disposed at the center of the first wall.

[0011] In the above design, by limiting the design position of the pressure relief mechanism, the pressure release can be made more uniform, thereby reducing the problem of local stress concentration.

[0012] In some embodiments, the first wall and the first part are both rectangular, the pressure relief mechanism is arranged at the center of the first wall, and along the length direction of the first wall, the distance between the pressure relief mechanism and the edge of the first part is d1, and the distance between the pressure relief mechanism and the edge of the first wall is d2, 0.6≤d1 / d2≤1.05.

[0013] In the above design, by reasonably limiting the ratio range of d1 and d2, normal heat dissipation of the battery cell can be ensured, while the use effect of the protective plate can be improved.

[0014] In some embodiments, 25 mm ≤ d1 ≤ 200 mm, and / or 40 mm ≤ d2 ≤ 190 mm.

[0015] In the above design, the size relationship between the pressure relief mechanism and the first part and the first wall is further defined, so that the design of the protective plate and the pressure relief mechanism is more reasonable.

[0016] In some embodiments, the first wall and the first part are both rectangular, the pressure relief mechanism is arranged at the center of the first wall, and along the width direction of the first wall, the distance between the pressure relief mechanism and the edge of the first part is d3, and the distance between the pressure relief mechanism and the edge of the first wall is d4, 0.8≤d3 / d4≤1.1.

[0017] In the above design, by reasonably limiting the ratio range of d3 and d4, normal heat dissipation of the battery cell can be ensured, and the use effect of the protective plate can be improved.

[0018] In some embodiments, 7 mm ≤ d3 ≤ 40 mm, and / or 10 mm ≤ d4 ≤ 35 mm.

[0019] In the above design, the size relationship between the pressure relief mechanism and the first part and the first wall is further defined, so that the design of the protective plate and the pressure relief mechanism is more reasonable.

[0020] In some embodiments, the surrounding wall includes two main shell walls and two side walls. The two main shell walls are arranged opposite to each other, and the two side walls are connected between the two main shell walls. The surface area of ​​the main shell wall is larger than the surface area of ​​the side wall, and the second part covers the outer side of the main shell wall.

[0021] In the above design, by setting the second part cover on the outside of the main shell wall, the risk of melting of the main shell wall can be effectively reduced. At the same time, by improving the structural design of the protective plate, the side wall is exposed, which is beneficial to improving the heat dissipation effect of the shell.

[0022] In some embodiments, the protective plate includes a heat insulation layer, an adhesive layer, and a support layer which are sequentially stacked along the plate thickness direction.

[0023] In the above design, the multi-layer structure of the protective plate works synergistically to provide more reliable protection for the battery cells, which is beneficial to further improve the safety of the battery cells.

[0024] In some embodiments, the protective plate is bonded to the housing by an adhesive.

[0025] In the above design, the protective plate and the outer shell are tightly fitted together, which can ensure the fixing effect between the two and is conducive to improving the reliability of the protective plate.

[0026] In some embodiments, the thermal conductivity of the protection plate is K1, the thermal conductivity of the housing is K2, and K1 / K2≤1 / 8.

[0027] In the above design, by reasonably limiting the ratio of K1 / K2, it can be ensured that the protective plate has a good heat insulation effect, and the protective plate can effectively isolate the heat from being continuously transferred to the vicinity of the pressure relief mechanism.

[0028] In some embodiments, 0.05 W / (m*K)≤K1≤10 W / (m*K).

[0029] In the above design, the thermal conductivity of the protection plate is further limited, making the design of the protection plate more reasonable.

[0030] In some embodiments, the thickness of the protective plate is D, 0.9 mm ≤ D ≤ 3.5 mm.

[0031] In the above design, the protective plate has sufficient mechanical strength and rigidity to effectively resist the thermal shock of the eruption material. At the same time, the amount of protective plate material used is moderate, which can not only meet the performance requirements but also avoid excessively high material costs, which is conducive to the lightweight design of battery cell products.

[0032] In some embodiments, the thermal expansion coefficient of the protective plate is λ, λ≤6×10 -6 / ℃.

[0033] In the above design, by reasonably limiting the range of the thermal expansion coefficient, the protective plate can have good structural stability. In this way, the size of the protective plate changes less when the temperature changes, and it can operate in a wider temperature range. At the same time, the protective plate is not prone to cracks, has better anti-aging properties, and can be used for a long time.

[0034] In some embodiments, the protective plate has a melting point of T, T≥1300°C.

[0035] In the above design, limiting the melting point of the protective plate within the above range is beneficial to improving the reliability of the protective plate.

[0036] An embodiment of a second aspect of the present application provides a battery device, comprising the battery cell of the first aspect.

[0037] The battery device provided in the embodiment of the present application improves the reliability and safety of the battery device by adopting the battery cell of the first aspect.

[0038] An embodiment of the third aspect of the present application provides an electrical device, including the battery cell in the first aspect or the battery device in the second aspect, and the battery cell or the battery device is used to store or provide electrical energy.

[0039] The electrical equipment provided in the embodiments of the present application improves the reliability and safety of the electrical equipment by adopting the battery cell in the first aspect or the battery device in the second aspect.

[0040] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or conventional technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0042] Figure 1 is a schematic structural diagram of a vehicle provided in an embodiment of the present application;

[0043] Figure 2 is an exploded view of a battery device provided in an embodiment of the present application;

[0044] Figure 3 is an exploded view of a battery cell provided in an embodiment of the present application;

[0045] Figure 4 is an exploded view of a battery cell provided in one embodiment of the present application;

[0046] Figure 5 yes Figure 4 A top view of the protective plate and the first wall in the battery cell shown;

[0047] Figure 6 is an exploded view of a battery cell provided in some other embodiments of the present application;

[0048] Figure 7 yes Figure 6 A side view of the protective plate in the battery cell is shown.

[0049] The meanings of the marks in the figure are:

[0050] 1000, vehicle; 100, battery device; 200, controller; 300, motor;

[0051] 10. Box body; 11. First box body; 12. Second box body;

[0052] 20. Battery cell; 21. Electrode assembly; 21a. Tab; 22. Electrode terminal; 23. Shell; 231. First wall; 232. Second wall; 233. Surrounding wall; 2331. Main shell wall; 2332. Side wall; 24. Pressure relief mechanism; 25. Protective plate; 251. First part; 2511. First avoidance hole; 2512. Second avoidance hole; 252. Second part. DETAILED DESCRIPTION

[0053] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0055] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0056] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0057] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0058] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0059] In the description of the embodiments of the present application, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the embodiments of the present application.

[0060] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0061] The battery cell generally includes a pressure relief mechanism, which can be opened when the battery cell experiences thermal runaway to release the runaway energy and runaway eruption generated by the thermal runaway, wherein the eruption may be a gaseous eruption, a solid particle eruption, or a liquid droplet eruption.

[0062] With the increase in the energy density of the battery system, the runaway energy generated by the thermal runaway of the battery cell has increased significantly. The eruption has the characteristics of large output, fast speed, and high temperature. During the discharge of the uncontrolled eruption, the outer shell of the battery cell is washed and the outer shell is easily melted. Among them, the shell melting includes the rupture of the shell due to impact and the melting of the shell material due to high temperature. In particular, since the eruption needs to be discharged from the shell through the pressure relief mechanism, the side of the shell where the pressure relief mechanism is set is subjected to greater impact force, and thus the risk of melting is higher. If the outer shell of the battery cell is damaged, the high-temperature gas and electrolyte sealed inside the shell will leak through the damaged part, increasing the risk of fire, explosion and environmental pollution. At the same time, the molten fragments generated by the outer shell and the electrode assembly may be ejected together with the high-temperature gas, which can easily ignite adjacent battery cells, causing heat to spread within the battery system and cause the battery system to fail.

[0063] Based on the above reasons, the present application provides a battery cell, including a shell, a pressure relief mechanism arranged on the first wall of the shell, and a protective plate covering the first wall of the shell and at least part of the outer side of the surrounding wall. The protective plate can provide reliable mechanical support for the shell, reduce the risk of deformation and rupture of the non-pressure relief area of ​​the first wall of the shell and the surrounding wall due to impact, and at the same time, the protective plate can also form an additional physical barrier on the outside of the first wall and the surrounding wall, reduce the risk of leakage gaps in the non-pressure relief area of ​​the first wall and the surrounding wall due to high-temperature melting, so that the safety of the battery cell can be effectively improved by setting the protective plate.

[0064] The battery device provided in the embodiment of the present application can be used in various energy storage systems that use the battery device as a power source or use the battery device as an energy storage element. The electrical equipment can be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, a battery car, an electric car, a ship, a spacecraft, and the like. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, and an electric airplane toy, and the like, and the spacecraft can include an airplane, a rocket, a space shuttle, and a spacecraft, and the like.

[0065] For the convenience of explanation, the embodiment of the present application is described by taking an electrical device as a vehicle 1000 as an example.

[0066] Please refer to Figure 1 , Figure 1A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 is provided inside the vehicle 1000, and the battery device 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery device 100 may be used to power the vehicle 1000, for example, the battery device 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery device 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0067] In some embodiments of the present application, the battery device 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0068] Please refer to Figure 2 , Figure 2 An exploded view of a battery device 100 provided in some embodiments of the present application. The battery device 100 includes a case 10 and a battery cell 20, and the battery cell 20 is contained in the case 10. Among them, the case 10 is used to provide a storage space for the battery cell 20, and the case 10 can adopt a variety of structures. In some embodiments, the case 10 may include a first case 11 and a second case 12, and the first case 11 and the second case 12 cover each other, and the first case 11 and the second case 12 jointly define a storage space for accommodating the battery cell 20. The second case 12 may be a hollow structure with one end open, and the first case 11 may be a plate-like structure, and the first case 11 covers the open side of the second case 12, so that the first case 11 and the second case 12 jointly define a storage space; the first case 11 and the second case 12 may also be hollow structures with one side open, and the open side of the first case 11 covers the open side of the second case 12. Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid, etc.

[0069] In some embodiments, the box 10 can be used as a part of the chassis structure of the vehicle 1000. For example, part of the box 10 can become at least a part of the floor of the vehicle 1000, or part of the box 10 can become at least a part of the cross beam and longitudinal beam of the vehicle 1000.

[0070] In some embodiments, the battery device 100 may not include the box body 10 , but rather a plurality of battery cells 20 may be connected and integrated into a whole by a necessary fixing structure and then assembled into the vehicle 1000 .

[0071] In the battery device 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a mixed connection. A mixed connection means that the multiple battery cells 20 are both connected in series and in parallel. The multiple battery cells 20 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells 20 is accommodated in the box 10; or, the multiple battery cells 20 may be first connected in series, in parallel, or in a mixed connection to form a battery cell assembly, and the multiple battery cell assemblies are then connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in the box 10. The battery device 100 may also include other structures, for example, the battery device 100 may also include a busbar component for realizing electrical connection between the multiple battery cells 20.

[0072] The battery cell 20 refers to the smallest unit constituting the battery device 100. Each battery cell 20 may be a secondary battery. A secondary battery refers to a battery cell 20 that can be continuously used by activating the active material by charging after the battery cell 20 is discharged. The battery cell 20 may be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, etc., but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0073] Please refer to Figure 3 , Figure 3 An exploded view of a battery cell 20 provided for some embodiments of the present application. The battery cell 20 includes an electrode assembly 21, an electrolyte and other functional components. The electrode assembly 21 is a component in the battery cell 20 where an electrochemical reaction occurs, and each battery cell 20 may include one or more electrode assemblies 21. The electrode assembly 21 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a diaphragm may also be provided between the positive electrode sheet and the negative electrode sheet. The portion of the positive electrode sheet and the negative electrode sheet having active materials constitutes the main body of the electrode assembly 21, and the portion of the positive electrode sheet and the negative electrode sheet without active materials each constitutes a tab 21a. The positive tab and the negative tab may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tab 21a connects the electrode terminal 22 to form a current loop.

[0074] The technical solution provided in the embodiments of the present application is described below with reference to the accompanying drawings.

[0075] According to some embodiments of the present application, referring to Figure 3 , and please refer to Figure 4 and Figure 5 , Figure 4 An exploded view of a battery cell 20 provided in some embodiments of the present application, Figure 5 for Figure 4A top view of the protective plate 25 and the first wall 231 in the battery cell 20 shown. An embodiment of the first aspect of the present application provides a battery cell 20. The battery cell 20 includes a shell 23, a pressure relief mechanism 24 and a protective plate 25. The shell 23 includes a first wall 231, a second wall 232 and a surrounding wall 233, the first wall 231 and the second wall 232 are arranged opposite to each other, and the surrounding wall 233 is connected between the first wall 231 and the second wall 232. The pressure relief mechanism 24 is arranged on the first wall 231. The protective plate 25 includes a first part 251 covering the outer side of the first wall 231 and a second part 252 covering the outer side of at least part of the surrounding wall 233, and the first part 251 is provided with a first avoidance hole 2511 for exposing the pressure relief mechanism 24.

[0076] The shell 23 is used to enclose a sealed receiving space, and the receiving space can be used to accommodate the electrode assembly 21, the electrolyte and other components. The shell 23 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism shape, etc. Specifically, the shape of the shell 23 can be determined according to the specific shape and size of the electrode assembly 21. The material of the shell 23 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. The first wall 231 and the second wall 232 are components of the shell 23, and the first wall 231 and the second wall 232 can be of various shapes and sizes, such as a circular or square planar structure. Among them, the side of the first wall 231 facing the receiving space is the inner side, and the side away from the receiving space is the outer side. The part of the first wall 231 where the pressure relief mechanism 24 is set is the pressure relief area, and the other parts are non-pressure relief areas. Along the distribution direction of the first wall 231 and the second wall 232, the surrounding wall 233 includes two opposite ends, and the two ends of the surrounding wall 233 are respectively perpendicular to the first wall 231 and the second wall 232 and sealed. The side of the surrounding wall 233 facing the receiving space is the inner side, and the side away from the receiving space is the outer side. The materials of the first wall 231, the surrounding wall 233 and the second wall 232 can be the same or different. Optionally, the first wall 231, the surrounding wall 233 and the second wall 232 can all be made of aluminum alloy. The surrounding wall 233 and the first wall 231 and the second wall 232 can be integrally formed or connected by welding or the like.

[0077] The pressure relief mechanism 24 refers to an element or component that is actuated to quickly release the internal pressure or temperature when the internal pressure or temperature of the battery cell 20 reaches a predetermined threshold. "Actuation" means that the pressure relief mechanism 24 produces an action or is activated to a certain state, wherein the action produced by the pressure relief mechanism 24 may include but is not limited to at least a part of the pressure relief mechanism 24 being broken, shattered, torn or opened. The pressure relief mechanism 24 may take the form of an explosion-proof valve, an air valve, a pressure relief valve or a safety valve, and may specifically adopt a pressure-sensitive or temperature-sensitive element or structure. When the internal pressure or temperature of the battery cell 20 reaches a predetermined threshold, the pressure relief mechanism 24 performs an action or the weak structure provided in the pressure relief mechanism 24 is destroyed, thereby forming an opening or channel for the internal pressure or temperature to be released. The ejecta discharged by the pressure relief mechanism 24 include but are not limited to: high-temperature and high-pressure gas produced by the reaction, electrolyte, dissolved or split positive and negative pole pieces, fragments of the separator, etc.

[0078] The first part 251 of the protective plate 25 covers the outer surface of the first wall 231, and can provide mechanical support for the first wall 231 and form a physical barrier outside the first wall 231. The first part 251 can be a flat plate structure, and grooves, protrusions or other forms can also be provided to adapt to the shape and layout of the first wall 231. The first part 251 has good rigidity, mechanical strength and high temperature resistance, and its material can be a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, hard metal or other composite materials. The first part 251 can be fixed to the first wall 231 by bonding, welding, etc., but is not limited to this. The first avoidance hole 2511 is a through hole that penetrates the first part 251 along the plate thickness direction of the first part 251. The setting position, size and shape of the first avoidance hole 2511 are determined according to the pressure relief mechanism 24.

[0079] The second part 252 of the protective plate 25 can cover at least part of the outer surface of the surrounding wall 233, and is at least arranged at one end of the surrounding wall 233 connected to the first wall 231. The second part 252 can provide mechanical support for the surrounding wall 233 and form a physical barrier outside the surrounding wall 233. The second part 252 can be a flat plate structure, and grooves, protrusions or other forms can also be provided to adapt to the shape and layout of the surrounding wall 233. The second part 252 has good rigidity, mechanical strength and high temperature resistance, and its material can be a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, hard metal or other composite materials. The second part 252 can be fixed to the surrounding wall 233 by means of clamping, bonding, welding, etc., but is not limited thereto.

[0080] The battery cell 20 provided in the embodiment of the present application includes a shell 23, a pressure relief mechanism 24 and a protective plate 25, wherein the shell 23 includes a first wall 231 and a surrounding wall 233, wherein the pressure relief mechanism 24 is arranged on the first wall 231, and the protective plate 25 includes a first portion 251 covering the outer side of the first wall 231 and a second portion 252 covering the outer side of at least part of the surrounding wall 233, so that the first portion 251 of the protective plate 25 can provide reliable mechanical support for the first wall 231, and the second portion 252 can provide reliable mechanical support for the surrounding wall 233. The protective plate 25 can provide reliable mechanical support for the portion close to the first wall 231, so that the risk of deformation and rupture due to impact in the non-pressure relief area of ​​the first wall 231 and the surrounding wall 233 near the first wall 231 can be reduced by setting the protective plate 25. At the same time, the protective plate 25 can form an additional physical barrier on the outside of the first wall 231 and at least part of the surrounding wall 233, reducing the risk of leakage gaps due to high-temperature melting in the non-pressure relief area of ​​the first wall 231 and the surrounding wall 233, so that this design effectively improves the safety of the battery cell 20. In addition, a first avoidance hole 2511 is provided on the first portion 251 of the protective plate 25, so that the pressure relief mechanism 24 can be directly exposed to the outside, ensuring that the pressure relief mechanism 24 can be used normally without being hindered by the protective plate 25.

[0081] In some embodiments, along the normal direction of the first wall 231 , the orthographic projection area of ​​the first portion 251 is S1 , the orthographic projection area of ​​the pressure relief mechanism 24 is S2 , and 1.5≤S1 / S2≤7.

[0082] The normal direction of the first wall 231 is a direction perpendicular to the surface of the first wall 231. It is assumed that there is a plane perpendicular to the normal direction of the first wall 231, and the plane is defined as a projection plane. The first part 251 and the pressure relief mechanism 24 are projected onto the projection plane along the normal direction of the first wall 231, and the orthographic projection area S1 of the first part 251 and the orthographic projection area S2 of the pressure relief mechanism 24 can be obtained.

[0083] S1 / S2 reflects the size relationship between the first part 251 and the pressure relief mechanism 24, and the size relationship between the two will affect the reliability of the protective plate 25. If S1 / S2 is too small, the first part 251 may not cover the first wall 231 enough, resulting in relatively poor support and protection of the first part 251 on the first wall 231; if S1 / S2 is too large, the first part 251 may cover too much on the first wall 231, which will affect the natural heat dissipation of the housing 23, thereby accelerating the occurrence of thermal runaway of the battery cell 20 and aggravating the degree of thermal runaway.

[0084] In the above embodiment, by reasonably limiting the ratio range of S1 to S2 , it is possible to ensure normal heat dissipation of the battery cell 20 and improve the use effect of the protective plate 25 , so that this design is conducive to further improving the safety of the battery cell 20 .

[0085] A set of experimental data is provided below to verify the effect of the technical solution provided in the above embodiment.

[0086]

[0087] Here, “shell integrity” refers to the structural integrity of the shell 23 . The smaller the melt-break area on the shell 23 , the higher the integrity of the shell 23 .

[0088] In some embodiments, 400 mm 2 ≤S1≤8500mm 2 , and / or 300mm 2 ≤S2≤1400mm 2 .

[0089] Optionally, in some embodiments provided in the present application, 1.5≤S1 / S2≤7,400mm 2 ≤S1≤8500mm 2 , 300mm 2 ≤S2≤1400mm 2 .

[0090] In the above embodiment, the size range of the first portion 251 of the protective plate 25 and the pressure relief mechanism 24 is further limited, so that the design of the protective plate 25 and the pressure relief mechanism 24 is more reasonable, which is beneficial to further improve the reliability of the protective plate 25 and the safety of the battery cell 20.

[0091] It can be understood that the sizes of the protective plate 25 and the pressure relief mechanism 24 are related to the structure of the battery cell 20 . Accordingly, the specific sizes of the protective plate 25 and the pressure relief mechanism 24 can be adjusted according to the structure of the battery cell 20 .

[0092] Please refer to Figure 4 and Figure 5 In some embodiments, the pressure relief mechanism 24 is disposed at the center of the first wall 231 .

[0093] The center of the first wall 231 can be understood as the center position of the first wall 231 in the geometric structure. For example, for a rectangular first wall 231, its center is the intersection of two diagonal lines, and for a circular first wall 231, its center is the center of the circle.

[0094] With the above design, when thermal runaway occurs in the battery cell 20 , the pressure can be released starting from the central part of the first wall 231 , so that the pressure release is more uniform, which helps to reduce the problem of local stress concentration.

[0095] It can be understood that in some other embodiments, in order to control the exhaust direction and guide the ejecta to be discharged along a specific path, the pressure relief mechanism 24 can also adopt an eccentric design.

[0096] Please refer to Figure 4 and Figure 5 In some embodiments, the first wall 231 and the first part 251 are both rectangular, the pressure relief mechanism 24 is arranged at the center of the first wall 231, and along the length direction X of the first wall 231, the distance between the pressure relief mechanism 24 and the edge of the first part 251 is d1, and the distance between the pressure relief mechanism 24 and the edge of the first wall 231 is d2, 0.6≤d1 / d2≤1.05.

[0097] like Figure 3 As shown, X indicates the length direction of the first wall 231 , Y indicates the width direction of the first wall 231 , and Z indicates the thickness direction of the first wall 231 . The length of the first wall 231 is not less than the width of the first wall 231 .

[0098] It should be noted that, since the pressure relief mechanism 24 has a certain size and occupies a certain space, the distance between the pressure relief mechanism 24 and the edge of the first portion 251 can be understood as: the distance between a point of the pressure relief mechanism 24 closest to the edge of the first portion 251 and the edge of the first portion 251. The distance between the pressure relief mechanism 24 and the edge of the first wall 231 is similar.

[0099] In the length direction X of the first wall 231, the first part 251 and the first wall 231 both include two opposite sides. Since the pressure relief mechanism 24 is located at the center position in the length direction X of the first wall 231, the pressure relief mechanism 24 is equidistant from the two side edges of the first part 251 and is also equidistant from the two side edges of the first wall 231.

[0100] d1 / d2 reflects the coverage effect of the first part 251 on the first wall 231 in the length direction X of the first wall 231, and the coverage effect is positively correlated with the value of d1 / d2. If d1 / d2 is too small, the coverage ratio may be insufficient and the coverage effect may be poor, resulting in relatively poor support and protection effect of the first part 251 on the first wall 231; if d1 / d2 is too large, the coverage ratio may be too large, which will affect the natural heat dissipation of the shell 23, thereby accelerating the occurrence of thermal runaway of the battery cell 20 and aggravating the degree of thermal runaway.

[0101] In the above embodiment, by reasonably limiting the ratio range of d1 to d2, normal heat dissipation of the battery cell 20 can be ensured, while improving the use effect of the protective plate 25. Therefore, this design is conducive to improving the reliability of the protective plate 25 and further improving the safety of the battery cell 20.

[0102] A set of experimental data is provided below to verify the effect of the technical solution provided by the above embodiment. In each comparative example provided in Table 2, the coverage range of the pressure relief mechanism 24 in the width direction Y is consistent.

[0103]

[0104] In some embodiments, 25 mm ≤ d1 ≤ 200 mm, and / or 40 mm ≤ d2 ≤ 190 mm.

[0105] Optionally, in some embodiments provided in the present application, 0.6≤d1 / d2≤1.05, 25mm≤d1≤200mm, 40mm≤d2≤190mm.

[0106] In the above embodiment, the size relationship between the pressure relief mechanism 24 and the first part 251 and the first wall 231 is further defined, so that the design of the protective plate 25 and the pressure relief mechanism 24 is more reasonable, which is beneficial to improve the reliability of the protective plate 25 and further improve the safety of the battery cell 20.

[0107] Please refer to Figure 4 and Figure 5 In some embodiments, the first wall 231 and the first part 251 are both rectangular, the pressure relief mechanism 24 is arranged at the center of the first wall 231, and along the width direction Y of the first wall 231, the distance between the pressure relief mechanism 24 and the edge of the first part 251 is d3, and the distance between the pressure relief mechanism 24 and the edge of the first wall 231 is d4, 0.8≤d3 / d4≤1.1.

[0108] In the width direction Y of the first wall 231, the first part 251 and the first wall 231 both include two opposite sides. Since the pressure relief mechanism 24 is located at the center position in the width direction Y of the first wall 231, the pressure relief mechanism 24 is equidistant from the two side edges of the first part 251 and is also equidistant from the two side edges of the first wall 231.

[0109] d3 / d4 reflects the coverage effect of the first part 251 on the first wall 231 in the width direction Y of the first wall 231, and the coverage effect is positively correlated with the numerical value of d3 / d4. If d3 / d4 is too small, the coverage ratio may be insufficient and the coverage effect may be poor, resulting in relatively poor support and protection effect of the first part 251 on the first wall 231; if d3 / d4 is too large, the coverage ratio may be too large, which will affect the natural heat dissipation of the housing 23, thereby accelerating the occurrence of thermal runaway of the battery cell 20 and aggravating the degree of thermal runaway.

[0110] In the above embodiment, by reasonably limiting the ratio range of d3 and d4, normal heat dissipation of the battery cell 20 can be ensured, while improving the use effect of the protective plate 25. Therefore, this design is conducive to improving the reliability of the protective plate 25 and further improving the safety of the battery cell 20.

[0111] A set of experimental data is provided below to verify the effect of the technical solution provided by the above embodiment. In each comparative example provided in Table 3, the coverage range of the pressure relief mechanism 24 in the length direction X is consistent.

[0112]

[0113] In some embodiments, 7 mm ≤ d3 ≤ 40 mm, and / or 10 mm ≤ d4 ≤ 35 mm.

[0114] Optionally, in some embodiments provided in the present application, 0.8≤d3 / d4≤1.1, 7mm≤d3≤40mm, and 10mm≤d4≤35mm.

[0115] In the above embodiment, the size relationship between the pressure relief mechanism 24 and the first part 251 and the first wall 231 is further defined, so that the design of the protective plate 25 and the pressure relief mechanism 24 is more reasonable, which is beneficial to improve the reliability of the protective plate 25 and further improve the safety of the battery cell 20.

[0116] Please refer to Figure 4 In some embodiments, the surrounding wall 233 includes two main shell walls 2331 and two side walls 2332. The two main shell walls 2331 are arranged opposite to each other, and the two side walls 2332 are connected between the two main shell walls 2331. The surface area of ​​the main shell wall 2331 is larger than the surface area of ​​the side walls 2332. The second part 252 is covered on the outer side of the main shell wall 2331.

[0117] The materials of the main shell wall 2331 and the side wall 2332 can be the same or different. Optionally, the main shell wall 2331 and the side wall 2332 can both be made of aluminum alloy. The main shell wall 2331 and the side wall 2332 can be integrally formed or connected by welding or the like.

[0118] Compared with the side wall 2332, the main shell wall 2331 is larger in size and bears most of the impact when the battery cell 20 has thermal runaway, and the risk of deformation and rupture after the impact is also greater. In particular, in some cases, the thickness of the main shell wall 2331 may be relatively small due to the processing and design requirements of the battery cell 20, which will further increase the risk of melting of the main shell wall 2331. In the above embodiment, by covering the outside of the main shell wall 2331 with the second part 252, the risk of melting of the main shell wall 2331 can be effectively reduced. At the same time, by improving the structural design of the protective plate 25, the side wall 2332 is exposed, which is conducive to improving the heat dissipation effect of the outer shell 23.

[0119] It can be understood that in some other embodiments, the protective plate 25 can also be covered on the side wall 2332.

[0120] Please refer to Figure 6 and Figure 7 , Figure 6 An exploded view of a battery cell 20 provided in some embodiments of the present application, Figure 7 for Figure 6 A side view of the protection plate 25 in the battery cell 20 is shown. In some embodiments, the first portion 251 and the second portion 252 of the protection plate 25 are integrally formed.

[0121] As an example, the outer shell 23 is in the shape of a rectangular parallelepiped, including a first wall 231 and a main shell wall 2331, and the protective plate 25 includes a first part 251 and a second part 252, the first part 251 is covered on the outer side of the first wall 231, and the second part 252 is covered on the outer side of the main shell wall 2331 and is arranged at one end of the main shell wall 2331 close to the first wall 231, and the first part 251 has two opposite sides in the width direction Y of the first wall 231, and the two sides are respectively connected to the second part 252.

[0122] The protection plate 25 can be clamped on the housing 23, or fixed on the housing 23 by bonding, welding, clamping, etc.

[0123] With the above design, the protection plate 25 has higher integrity and strength. The protection plate 25 can cover the connection position between the first wall 231 and the surrounding wall 233 and protect the weak part of the connection.

[0124] Please refer to 4 , in some embodiments, the first portion 251 and the second portion 252 of the protective plate 25 are independently provided.

[0125] In some cases, when the first portion 251 and the second portion 252 are independently provided, each portion can be individually fixed to the housing 23 of the battery cell 20 , and the portions can be butted against each other.

[0126] As an example, the housing 23 is in a rectangular parallelepiped shape, including a first wall 231 and two main housing walls 2331 connected to the first wall 231, and the protective plate 25 includes a first portion 251 covering the first wall 231 and a second portion 252 covering the main housing walls 2331. The protective plate 25 can be fixed to the housing 23 by bonding, welding, or the like.

[0127] The above design improves the design flexibility of the protection plate 25 , thereby facilitating reducing the difficulty of assembling the protection plate 25 and the housing 23 .

[0128] In some embodiments, the protection plate 25 is bonded to the housing 23 by an adhesive.

[0129] The adhesive may be, but is not limited to, a high temperature resistant epoxy resin.

[0130] With the above design, the structural integrity of the housing 23 can be maintained, and the protective plate 25 can fit tightly against the housing 23 , thereby providing more reliable protection for the housing 23 .

[0131] Please refer to Figure 4 and Figure 6 In some embodiments, the battery cell 20 includes an electrode terminal 22 , which is disposed on the first wall 231 , and a second avoidance hole 2512 for exposing the electrode terminal 22 is disposed on the first portion 251 .

[0132] For example, the first wall 231 is provided with two electrode terminals 22 , the two electrode terminals 22 have different polarities and are respectively located at two opposite sides of the pressure relief mechanism 24 .

[0133] The battery cell 20 includes an electrode assembly 21 disposed in a housing 23, and the electrode terminal 22 can be used to be electrically connected to the electrode assembly 21 to output or input electrical energy of the battery cell 20. The second avoidance hole 2512 is a through hole that penetrates the plate surface of the first portion 251, and the setting position, size and shape of the second avoidance hole 2512 are determined according to the electrode terminal 22.

[0134] In some embodiments, an insulating member may be provided inside the first wall 231, and the insulating member may be used to isolate the electrical connection components in the receiving space from the first wall 231 to reduce the risk of short circuit. For example, the insulating member may be plastic, rubber, or the like.

[0135] It can be understood that in some other embodiments, the electrode terminal 22 can also be disposed on the second wall 232 or the side wall 2332 .

[0136] In some embodiments, the protective plate 25 includes a heat insulation layer, an adhesive layer and a support layer which are sequentially stacked along the plate thickness direction. The heat insulation layer or the support layer is arranged close to the outer shell 23 .

[0137] As an example, the material of the thermal insulation layer may include one or more of ZrO2, Al2O3, SiC, SiO2, BN, glass powder, and carbon fiber; the material of the bonding layer may include silicone resin and / or polycarbosilane; and the supporting layer may be a lightweight polymer board containing reinforcing ribs.

[0138] As an example, the production process of the protective plate 25 may include: material preparation, including providing insulation layer slurry, adhesive layer slurry and lightweight polymer board; grinding, including using a sand grinder to grind the insulation layer slurry to a particle fineness of 40μm-50μm; coating, including using an air spray method to coat the adhesive layer slurry and the insulation layer slurry onto the surface of the lightweight polymer board, wherein the air pressure is set to 0.4MPa during coating, and the spraying diameter is 0.8mm-1mm; curing, including placing the protective plate 25 at room temperature for 48 hours, and baking it at 200°C for 2 hours to solidify into a film.

[0139] In the above embodiment, by designing a heat insulation layer, the heat insulation effect of the protective plate 25 is improved, so that the protective plate 25 can effectively block the high temperature conduction near the pressure relief mechanism 24, thereby reducing the risk of heat spread; by designing a supporting layer, the mechanical strength and rigidity of the protective plate 25 can be guaranteed, so that the protective plate 25 can resist impact and pressure from inside and outside the outer shell 23, so that the multi-layer structure of the protective plate 25 works synergistically to provide more reliable protection for the battery cell 20, which is conducive to further improving the safety of the battery cell 20.

[0140] In some embodiments, the thermal conductivity of the protection plate 25 is K1, the thermal conductivity of the housing 23 is K2, and K1 / K2≤1 / 8.

[0141] Thermal conductivity is a physical quantity that indicates the thermal conductivity of a material. The larger the thermal conductivity, the better the thermal conductivity. If the thermal conductivity of the protective plate 25 is significantly smaller than the thermal conductivity of the outer shell 23, the protective plate 25 has a better thermal insulation effect than the outer shell 23 and can form an efficient thermal insulation barrier in a local area of ​​the outer shell 23; if the thermal conductivity of the protective plate 25 is similar to that of the outer shell 23, the protective plate 25 may have a poor thermal insulation effect.

[0142] In the above embodiment, by reasonably limiting the ratio of K1 / K2, it can be ensured that the protective plate 25 has a good heat insulation effect, and the protective plate 25 can effectively isolate the heat from being continuously transferred to the vicinity of the pressure relief mechanism 24, thereby reducing the risk of melting of the shell 23.

[0143] For the protective plate 25 of the composite structure, its thermal conductivity can be measured in a variety of ways. For example, the protective plate 25 can be clamped using a hot plate, and the temperature change of the protective plate 25 can be obtained by adjusting the temperature, time and pressure of the hot plate. The thermal conductivity of the protective plate 25 can be further calculated, and the thermal insulation capacity of the protective plate 25 can be judged.

[0144] In some embodiments, 0.05 W / (m*K)≤K1≤10 W / (m*K).

[0145] Optionally, in a specific embodiment, K1 / K2≤1 / 8, 0.05W / (m*K)≤K1≤10W / (m*K).

[0146] By adopting the above design, the thermal conductivity of the protection plate 25 is further limited, making the design of the protection plate 25 more reasonable.

[0147] In some embodiments, the thickness of the protective plate 25 is D, and 0.9 mm≤D≤3.5 mm.

[0148] The thickness of the protective plate 25 will affect the supporting effect and heat insulation effect of the protective plate 25. On the one hand, the above design can ensure that the protective plate 25 has sufficient mechanical strength and rigidity, and the protective plate 25 can effectively resist the thermal shock of the eruption, thereby providing protection for the outer shell 23; on the other hand, within this thickness range, the material usage of the protective plate 25 is moderate, which can not only meet the performance requirements but also avoid excessively high material costs, which is conducive to realizing the lightweight design of the battery cell 20 product.

[0149] In some embodiments, the thermal expansion coefficient of the protective plate 25 is λ, λ≤6×10 -6 / ℃.

[0150] The coefficient of thermal expansion refers to the degree to which a material changes size when the temperature changes. A low coefficient of thermal expansion can provide better dimensional stability, reduce thermal stress, improve precision and enhance durability.

[0151] In the above embodiment, by reasonably limiting the range of the thermal expansion coefficient, the protective plate 25 can have good structural stability. In this way, the protective plate 25 has a smaller size change when the temperature changes and can operate within a wider temperature range. At the same time, the protective plate 25 is less likely to crack and has better anti-aging properties and can be used for a long time.

[0152] In some embodiments, the melting point of the protection plate 25 is T, where T≥1300°C.

[0153] In the current design of high-density battery cells 20, the outer shell 23 is generally made of metal materials such as aluminum and steel. In particular, for battery cells 20 with an energy density VED≥650Wh / L, the melting point of the outer shell 23 does not exceed 1200°C. Limiting the melting point of the protective plate 25 to the above range is beneficial to improving the reliability of the protective plate 25.

[0154] In one embodiment provided by the present application, the battery cell 20 includes a shell 23, a pressure relief mechanism 24 and a protective plate 25. The shell 23 includes a first wall 231 and a main shell wall 2331 connected to the first wall 231, and the pressure relief mechanism 24 and the electrode terminal 22 are arranged on the first wall 231. The protective plate 25 includes a first part 251 and a second part 252, the first part 251 is covered on the outside of the first wall 231, and the first wall 231 is provided with a first avoidance hole 2511 for exposing the pressure relief mechanism 24 and a second avoidance hole 2512 for exposing the electrode terminal 22, and the second part 252 is covered on the main shell wall 2331 at a position close to the first wall 231. The area ratio S1 / S2 of the first part 251 and the pressure relief mechanism 24 is set between 1.5-7. The thermal conductivity K1 of the protective plate 25 is less than the thermal conductivity K2 of the shell 23, and the ratio K1 / K2 of the two does not exceed 1:8. The protective plate 25 includes a heat insulation layer, an adhesive layer and a support layer. The thickness D of the protective plate 25 ranges from 0.9 mm to 3.5 mm. The thermal expansion coefficient λ of the protective plate 25 does not exceed 6×10 -6 / ℃, the melting point T does not exceed 1300℃. The battery cell 20 provided in the above embodiment has the following advantages: 1. The protective plate 25 provides reliable mechanical support for the outer shell 23, reducing the risk of deformation and rupture of the outer shell 23 due to impact; 2. The protective plate 25 forms an additional physical barrier on the outside of the outer shell 23, reducing the risk of leakage gaps in the outer shell 23 due to high temperature melting; 3. By reasonably limiting the size of the protective plate 25, the reliability of the protective plate 25 can be guaranteed, while ensuring that the battery cell 20 can dissipate heat normally; 4. By limiting the thermal conductivity, thermal expansion coefficient and melting point of the protective plate 25, the thermal insulation effect of the protective plate 25 can be improved, thereby isolating the heat from being continuously transferred to the vicinity of the pressure relief mechanism 24. In summary, through the above design, the risks of melting of the outer shell 23, heat spread, etc. when the battery cell 20 has thermal runaway can be effectively reduced, thereby improving the safety of the battery cell 20.

[0155] An embodiment of a second aspect of the present application provides a battery device 100 , comprising the battery cell 20 in the first aspect.

[0156] The battery device 100 provided in the embodiment of the present application improves the reliability and safety of the battery device 100 by adopting the battery cell 20 in the first aspect.

[0157] An embodiment of the third aspect of the present application provides an electrical device, the battery cell 20 in the first aspect or the battery device 100 in the second aspect, the battery cell 20 or the battery device 100 is used to store or provide electrical energy.

[0158] The electrical equipment provided in the embodiment of the present application improves the reliability and safety of the electrical equipment by adopting the battery cell 20 in the first aspect or the battery device 100 in the second aspect.

[0159] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: The housing comprises a first wall, a second wall and a surrounding wall, wherein the first wall and the second wall are arranged opposite to each other, and the surrounding wall is connected between the first wall and the second wall; A pressure relief mechanism, disposed on the first wall; The protective plate comprises a first portion covering the outer side of the first wall and a second portion covering the outer side of at least a portion of the surrounding wall, wherein the first portion is provided with a first avoidance hole for exposing the pressure relief mechanism.

2. The battery cell according to claim 1, characterized in that: Along the normal direction of the first wall, the orthographic projection area of ​​the first portion is S1, the orthographic projection area of ​​the pressure relief mechanism is S2, and 1.5≤S1 / S2≤7.

3. The battery cell according to claim 2, characterized in that: 400mm 2 ≤S1≤8500mm 2 , and / or 300mm 2 ≤S2≤1400mm 2 .

4. The battery cell according to claim 1, characterized in that: The pressure relief mechanism is arranged at the center of the first wall.

5. The battery cell according to claim 4, characterized in that: The first wall and the first part are both rectangular. Along the length direction of the first wall, the distance between the pressure relief mechanism and the edge of the first part is d1, and the distance between the pressure relief mechanism and the edge of the first wall is d2, and 0.6≤d1 / d2≤1.

05.

6. The battery cell according to claim 5, characterized in that: 25mm≤d1≤200mm, and / or 40mm≤d2≤190mm.

7. The battery cell according to claim 4, characterized in that: The first wall and the first part are both rectangular. Along the width direction of the first wall, the distance between the pressure relief mechanism and the edge of the first part is d3, and the distance between the pressure relief mechanism and the edge of the first wall is d4, and 0.8≤d3 / d4≤1.

1.

8. The battery cell according to claim 7, characterized in that: 7mm≤d3≤40mm, and / or 10mm≤d4≤35mm.

9. The battery cell according to claim 1, characterized in that: The surrounding wall includes two main shell walls and two side walls. The two main shell walls are arranged opposite to each other. The two side walls are connected between the two main shell walls. The surface area of ​​the main shell wall is larger than the surface area of ​​the side wall. The second part covers the outer side of the main shell wall.

10. The battery cell according to any one of claims 1 to 9, characterized in that: The protective plate comprises a heat insulation layer, an adhesive layer and a support layer which are sequentially stacked along the plate thickness direction.

11. The battery cell according to any one of claims 1 to 9, characterized in that: The protection plate is bonded to the housing by an adhesive.

12. The battery cell according to any one of claims 1 to 9, characterized in that: The thermal conductivity of the protective plate is K1, the thermal conductivity of the shell is K2, and K1 / K2≤1 / 8.

13. The battery cell according to claim 12, characterized in that: 0.05W / (m*K)≤K1≤10W / (m*K).

14. The battery cell according to any one of claims 1 to 9, characterized in that: The thickness of the protective plate is D, 0.9 mm ≤ D ≤ 3.5 mm, and / or the thermal expansion coefficient of the protective plate is λ, λ ≤ 6×10 -6 / ℃, and / or the melting point of the protective plate is T, T≥1300℃.

15. A battery device, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 14.

16. An electrical equipment, characterized in that: The invention comprises the battery cell according to any one of claims 1 to 14 or the battery device according to claim 15, wherein the battery cell or the battery device is used for storing or providing electric energy.

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