Battery cell, battery and electrical device

Abstract

The present application relates to the field of batteries, and provides a battery cell, a battery and an electrical device. The battery cell comprises a casing, an electrode assembly and a protective member, the electrode assembly being accommodated in the casing, the electrode assembly comprising a positive electrode sheet, a negative electrode sheet and a separator, and the positive electrode sheet, the separator and the negative electrode sheet being wound or stacked to form the electrode assembly. The protective member covers at least part of the outer surface of the casing, and the protective member comprises a thermal insulation layer, the thermal insulation layer being used for suppressing the heat of the electrode assembly from transferring to the side of the protective member facing away from the casing, and the thermal conductivity of the thermal insulation layer being less than or equal to 0.5. The battery cell is provided with the protective member, and the protective member covers at least part of the outer surface of the casing. The protective member has the thermal insulation layer, such that when thermal runaway occurs in one battery cell, the protective member can prevent heat from being transferred to another battery cell adjacent to the battery cell to a certain extent, thereby reducing the risk of thermal runaway occurring in another battery cell adjacent to the battery cell, and helping to improve the battery reliability.

Description

Battery cell, battery and electric device

[0001] Cross-reference to related applications

[0002] This application claims priority to the Chinese patent application with the title "Battery cell, battery and electric device" filed on June 07, 2024 (application number: 2024107408513), the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the field of batteries, in particular to a battery cell, a battery and an electric device. BACKGROUND

[0004] Batteries are widely used in the field of new energy, for example, electric vehicles, new energy vehicles, etc. New energy vehicles and electric vehicles have become a new trend in the development of the automotive industry. The development of battery technology needs to consider various design factors, such as battery life, energy density, discharge capacity, charge-discharge rate, and other performance parameters. In addition, the reliability of the battery also needs to be considered. However, the reliability of the current battery is poor.

[0005] SUMMARY

[0006] The purpose of the embodiments of the present application is to provide a battery cell, a battery and an electric device, which aims to improve the problem of poor reliability of the battery in the related art.

[0007] In a first aspect, the embodiments of the present application provide a battery cell, which comprises a shell, an electrode assembly and a protective member, the electrode assembly is contained in the shell, the electrode assembly comprises a positive electrode sheet, a negative electrode sheet and a separator, the positive electrode sheet, the separator and the negative electrode sheet are wound or stacked to form the electrode assembly, the protective member covers at least a part of the outer surface of the shell, the protective member comprises a thermal insulation layer, the thermal insulation layer is used to inhibit the conduction of heat of the electrode assembly to the side of the protective member away from the shell, and the thermal conductivity coefficient of the thermal insulation layer is less than or equal to 0.5.

[0008] In the above technical solution, the battery cell is provided with a protective member, which covers at least a part of the outer surface of the shell. The protective member has a thermal insulation layer, which has a good barrier effect on heat by making the thermal conductivity coefficient of the thermal insulation layer less than or equal to 0.5, and can effectively inhibit the conduction of heat to the side of the protective member away from the shell. When one battery cell experiences thermal runaway, the protective member can to some extent prevent the heat from being transmitted to another battery cell adjacent to the battery cell, reducing the risk of thermal runaway of another battery cell adjacent to the battery cell, and is beneficial to improving the reliability of the battery.

[0009] As an optional technical solution of the embodiment of the present application, the nickel content of the positive electrode active material of the positive electrode sheet is greater than or equal to 40% and less than 65%, and the melting point of the heat insulation layer is greater than or equal to 150 DEG C.

[0010] In the above technical solution, when the nickel content of the positive electrode active material of the positive electrode sheet is greater than or equal to 40% and less than 65%, the heat generated by the thermal runaway of the battery cell is large, and by making the melting point of the heat insulation layer greater than or equal to 150 DEG C, the high temperature generated by the thermal runaway can be effectively resisted, so that the heat insulation layer is not easy to be burned through.

[0011] As an optional technical solution of the embodiment of the present application, the nickel content of the positive electrode active material of the positive electrode sheet is greater than or equal to 65%, the melting point of the heat insulation layer is greater than or equal to 500 DEG C, and the thermal conductivity of the heat insulation layer is less than or equal to 0.26.

[0012] In the above technical solution, when the nickel content of the positive electrode active material of the positive electrode sheet is greater than or equal to 65%, the heat generated by the thermal runaway of the battery cell is larger, and by making the melting point of the heat insulation layer greater than or equal to 500 DEG C, the high temperature generated by the thermal runaway can be more effectively resisted, so that the heat insulation layer is not easy to be burned through. By making the thermal conductivity of the heat insulation layer less than or equal to 0.26, the heat insulation effect is better, and the heat conduction to the side of the protection away from the shell can be more effectively inhibited.

[0013] As an optional technical solution of the embodiment of the present application, the protection includes an insulating layer, and the insulating layer is stacked with the heat insulation layer.

[0014] In the above technical solution, the protection further includes an insulating layer, so that the protection has an insulating effect, and the protection can insulate and isolate the shell from other electrically connected components, thereby reducing the risk of short circuit caused by the contact between the shell and other electrically connected components.

[0015] As an optional technical solution of the embodiment of the present application, the protection includes a plurality of heat insulation layers, and the insulating layer is arranged between two adjacent heat insulation layers.

[0016] In the above technical solution, by arranging a plurality of heat insulation layers, the heat insulation effect of the protection can be improved. By arranging the insulating layer between the two adjacent heat insulation layers, the insulating layer is not easy to be ablated by high temperature, and the insulating effect of the protection can be improved.

[0017] As an optional technical solution of the embodiment of the present application, the side of the heat insulation layer away from the shell is provided with the insulating layer.

[0018] In the technical solution, when the insulation layer is arranged on the side of the thermal insulation layer away from the shell, the outermost layer of the protection member is the insulation layer, the insulation layer can insulate the thermal insulation layer from other electrical connection components, and the risk of conduction of the other two electrical connection components by the thermal insulation layer is reduced. In addition, the insulation layer can protect the thermal insulation layer, reduce the risk of damage to the thermal insulation layer, and enable the protection member to stably play a heat insulation role. Furthermore, the insulation layer can also support the thermal insulation layer, reducing the risk of the thermal insulation layer falling off.

[0019] As an optional technical solution of the embodiment, the protection member comprises one or more layers of the insulation layer, and the total thickness of the one or more layers of the insulation layer is D1, which satisfies 0.05mm≤D1≤0.1mm.

[0020] In the technical solution, when D1≥0.05mm, the total thickness of the one or more layers of the insulation layer is large, and the insulation effect is good. When D1≤0.1mm, the total thickness of the one or more layers of the insulation layer is not too large, on the one hand, the occupation of the internal space of the battery is reduced, and the energy density of the battery is improved. On the other hand, the insulation layer can be reasonably utilized, unnecessary material consumption is reduced, and the cost of the battery monomer is reduced. Therefore, when 0.05mm≤D1≤0.1mm, the insulation effect and the energy density of the battery can be considered.

[0021] As an optional technical solution of the embodiment, the thermal insulation layer is made of insulating material.

[0022] In the technical solution, the thermal insulation layer is made of insulating material, so that the thermal insulation layer not only has heat insulation and heat resistance, but also has insulation. In this way, the thermal insulation layer can insulate the shell from other electrical connection components, reducing the risk of short circuit caused by contact between the shell and other electrical connection components.

[0023] As an optional technical solution of the embodiment, the protection member comprises one or more layers of the thermal insulation layer, and the total thickness of the one or more layers of the thermal insulation layer is D2, which satisfies 0.05mm≤D2≤0.3mm.

[0024] In the technical solution, when D2≥0.05mm, the total thickness of the one or more layers of the thermal insulation layer is large, and the heat insulation effect is good. When D2≤0.3mm, the total thickness of the one or more layers of the thermal insulation layer is not too large, on the one hand, the occupation of the internal space of the battery is reduced, and the energy density of the battery is improved. On the other hand, the thermal insulation layer can be reasonably utilized, unnecessary material consumption is reduced, and the cost of the battery monomer is reduced. Therefore, when 0.05mm≤D2≤0.3mm, the heat insulation effect and the energy density of the battery can be considered.

[0025] As an optional technical solution of the embodiment of the present application, the material of the shell comprises a steel material, and the following condition is met: 0.05mm≤D2≤0.2mm.

[0026] In the above technical solution, when the material of the shell comprises a steel material, the thermal conductivity of the steel material is relatively low, and therefore the total thickness of the one or more thermal insulation layers can be set to be relatively small. That is, when the material of the shell comprises a steel material, the total thickness of the one or more thermal insulation layers is limited within 0.05-0.2mm, and the heat insulation effect and the energy density of the battery can be better balanced.

[0027] As an optional technical solution of the embodiment of the present application, the material of the shell comprises an aluminum material, and the following condition is met: 0.2mm≤D2≤0.3mm.

[0028] In the above technical solution, when the material of the shell comprises an aluminum material, the thermal conductivity of the aluminum material is relatively high, and therefore the total thickness of the one or more thermal insulation layers can be set to be relatively large. That is, when the material of the shell comprises an aluminum material, the total thickness of the one or more thermal insulation layers is limited within 0.2-0.3mm, and the heat insulation effect and the energy density of the battery can be better balanced.

[0029] As an optional technical solution of the embodiment of the present application, the protective member comprises an adhesive layer, and the adhesive layer is attached to the outer surface of the shell.

[0030] In the above technical solution, the adhesive layer has adhesion, and the protective member can be quickly attached to the outer surface of the shell by setting the adhesive layer, and the connection between the protective member and the shell is relatively firm, and the risk of the protective member separating from the shell is reduced.

[0031] As an optional technical solution of the embodiment of the present application, the thickness of the adhesive layer is D3, and the following condition is met: 0.01mm≤D3≤0.1mm.

[0032] In the above technical solution, when D3≥0.01mm, the thickness of the adhesive layer is large, and the adhesive effect is good. When D3≤0.1mm, the thickness of the adhesive layer is not too large, on the one hand, the occupation of the internal space of the battery can be reduced, and the energy density of the battery can be improved. On the other hand, the adhesive layer can be reasonably utilized, unnecessary material consumption can be reduced, and the cost of the battery monomer can be reduced. Therefore, when 0.01mm≤D3≤0.1mm, the adhesive effect and the energy density of the battery can be balanced.

[0033] As an optional technical solution of the embodiment of the present application, the material of the shell comprises a steel material, and the following condition is met: 0.03mm≤D3≤0.1mm.

[0034] In the technical solution, when the material of the shell comprises steel material, the outer surface of the shell is relatively smooth, and thus a relatively thick adhesive layer is needed to realize the bonding, i.e., when the material of the shell comprises steel material, the thickness of the bonding layer is limited within 0.03-0.1 mm, which can better balance the bonding effect and the energy density of the battery.

[0035] In an optional technical solution of the embodiment, the material of the shell comprises aluminum material, and the following condition is met: 0.01 mm≤D3≤0.05 mm.

[0036] In the technical solution, when the material of the shell comprises aluminum material, the outer surface of the shell is relatively rough, and thus a relatively thin adhesive layer can be used to realize the bonding, i.e., when the material of the shell comprises aluminum material, the thickness of the bonding layer is limited within 0.01-0.05 mm, which can better balance the bonding effect and the energy density of the battery.

[0037] In an optional technical solution of the embodiment, the minimum thickness of the shell is H1, and the thickness of the protective member is D, and the following condition is met: 0.7 mm≤H1+D≤3 mm.

[0038] In the technical solution, since the shell can also have a certain heat insulation effect, when the shell is relatively thick, the thickness of the protective member can be set to be relatively small. When the shell is relatively thin, the thickness of the protective member can be set to be relatively large. When H1+D≥0.7 mm, the sum of the minimum thickness of the shell and the thickness of the protective member is relatively large, and thus the heat insulation effect is good. When H1+D≤3 mm, the sum of the minimum thickness of the shell and the thickness of the protective member is not too large, on the one hand, the occupation of the internal space of the battery can be reduced, which is beneficial to improving the energy density of the battery. On the other hand, the protective member can be reasonably used, unnecessary material consumption is reduced, and the cost of the battery monomer is reduced. Therefore, when 0.7 mm≤H1+D≤3 mm, the heat insulation effect and the energy density of the battery can be balanced.

[0039] In an optional technical solution of the embodiment, 0.1 mm≤D≤0.6 mm, and / or, 0.3 mm≤H1≤2 mm.

[0040] In the technical solution, when D≥0.1 mm, the thickness of the protective member is relatively large, the protective member has high strength, and has good protection effect. In addition, the heat insulation layer can be set to be relatively thick, and has good heat insulation effect. When D≤0.6 mm, the thickness of the protective member is not too large, on the one hand, the occupation of the internal space of the battery can be reduced, which is beneficial to improving the energy density of the battery. On the other hand, the protective member can be reasonably used, unnecessary material consumption is reduced, and the cost of the battery monomer is reduced. Therefore, when 0.1 mm≤D≤0.6 mm, the protection effect and the energy density of the battery can be balanced.

[0041] When H1 is greater than or equal to 0.3 mm, the minimum thickness of the shell is relatively large, the shell has high strength, and the electrode assembly in the shell is well protected. When H1 is less than or equal to 2 mm, the minimum thickness of the shell is not too large, on the one hand, the occupation of the internal space of the battery can be reduced, and the energy density of the battery can be improved. On the other hand, the shell can be reasonably utilized, unnecessary material consumption can be reduced, and the cost of the battery monomer can be reduced. Therefore, when 0.3 mm≤H1≤2 mm, the protection effect and the energy density of the battery can be considered.

[0042] As an optional technical solution of the embodiment of the application, the shell comprises a shell body and an end cover, the shell body is formed with an opening at least at one end in a first direction, and the end cover seals the opening; the protection member comprises a main body portion and a first flange portion, the main body portion covers the outer surface of the shell body, and the first flange portion is connected to one end of the main body portion in the first direction, and covers at least a part of the outer surface of the end cover.

[0043] In the above technical solution, the main body portion can cover the outer surface of the shell body, and the first flange portion can cover at least a part of the outer surface of the end cover. In this way, the protection member can cover the corner position where the end cover and the shell body are connected. On the one hand, the corner position where the end cover and the shell body are connected can be protected. On the other hand, the risk of sharp-end discharge can be reduced.

[0044] As an optional technical solution of the embodiment of the application, the width of the first flange portion is L1, and 2 mm≤L1≤20 mm is satisfied.

[0045] In the above technical solution, when L1 is greater than or equal to 2 mm, the width of the first flange portion is relatively large, the first flange portion can cover a larger area of the outer surface of the end cover, the protection effect of the protection member on the corner position where the end cover and the shell body are connected can be improved, and the risk of sharp-end discharge can be further reduced. When L1 is less than or equal to 20 mm, the width of the first flange portion is not too large, so that the first flange portion is not easy to interfere with other components on the end cover. Therefore, when 2 mm≤L1≤20 mm, the protection effect and the risk of interference with other components can be considered.

[0046] As an optional technical solution of the embodiment of the application, the shell comprises a side wall and a bottom wall, the side wall and the bottom wall are integrally formed, one end of the side wall is connected to the bottom wall in the first direction, the other end of the side wall encloses the opening, and the main body portion covers the outer surface of the side wall; the protection member further comprises a second flange portion, the second flange portion is connected to one end of the main body portion opposite to the first flange portion in the first direction, and covers at least a part of the outer surface of the bottom wall.

[0047] In the technical solution, the main body part can be wrapped on the outer surface of the side wall, and the second flange part can be wrapped on at least part of the outer surface of the bottom wall. In this way, the protector can wrap the corner position where the bottom wall and the side wall are connected. On the one hand, the corner position where the bottom wall and the side wall are connected can be protected. On the other hand, the risk of sharp-end discharge can be reduced.

[0048] As an optional technical solution of the embodiment of the present application, the width of the second flange part is L2, and 2mm≤L2≤20mm is met.

[0049] In the technical solution, when L2≥2mm, the width of the second flange part is large, the second flange part can cover a large area of the outer surface of the bottom wall, the protection effect of the protector on the corner position where the side wall and the bottom wall are connected is improved, and the risk of sharp-end discharge is further reduced. When L2≤20mm, the width of the second flange part is not too large, which is beneficial to reduce material consumption and production cost. Therefore, when 2mm≤L2≤20mm, the protection effect and cost reduction can be considered.

[0050] As an optional technical solution of the embodiment of the present application, the heat insulation layer comprises at least one of ceramic material, stone wool material, rock wool material, and aerogel felt material.

[0051] In the technical solution, the ceramic material, the stone wool material, the rock wool material, and the aerogel felt material all have good heat insulation effect, can withstand high temperature, and also have insulation effect, so that the heat insulation layer can not only withstand heat and insulate heat, but also insulate. In addition, the cost of the ceramic material, the stone wool material, the rock wool material, and the aerogel felt material is relatively low.

[0052] In a second aspect, the embodiment of the present application also provides a battery, which comprises the battery monomer.

[0053] As an optional technical solution of the embodiment of the present application, the battery comprises a plurality of battery monomers, and a heat insulation pad is arranged between the protectors of two adjacent battery monomers.

[0054] In the technical solution, the heat insulation pad is arranged between the protectors of two adjacent battery monomers, and the heat insulation effect is further improved. When thermal runaway occurs in one battery monomer, the protector and the heat insulation pad can prevent heat from being transmitted to another battery monomer adjacent to the battery monomer to a certain extent, further reducing the risk of thermal runaway of another battery monomer adjacent to the battery monomer, and improving the reliability of the battery.

[0055] As an optional technical solution of the embodiment of the present application, the thickness of the heat insulation pad is H2, and 1.5mm≤H2≤4mm is met.

[0056] In the technical solution, when H2 is greater than or equal to 1.5 mm, the thickness of the thermal insulation pad is relatively large, and the thermal insulation pad has a good thermal insulation effect. When H2 is less than or equal to 4 mm, the thickness of the thermal insulation pad is not too large, on the one hand, the thermal insulation pad can reduce the occupation of the internal space of the battery, and the energy density of the battery can be improved. On the other hand, the thermal insulation pad can be reasonably used, unnecessary material consumption can be reduced, and the cost of the battery monomer can be reduced. Therefore, when 1.5 mm≤H2≤4 mm, the thermal insulation effect and the energy density of the battery can be considered. In addition, due to the presence of the protection member, the thickness of the thermal insulation pad can be relatively reduced, and the energy density of the battery can be further improved.

[0057] In a third aspect, the embodiments of the present application also provide a power utilization device, which comprises the battery monomer described above, and the battery monomer is used to provide electric energy for the power utilization device. BRIEF DESCRIPTION OF DRAWINGS

[0058] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be considered as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0059] FIG. 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application;

[0060] FIG. 2 is an exploded view of a battery according to some embodiments of the present application;

[0061] FIG. 3 is an exploded view of a battery monomer according to some embodiments of the present application;

[0062] FIG. 4 is a structural schematic diagram of a battery monomer according to some embodiments of the present application;

[0063] FIG. 5 is a sectional view of a protection member according to some embodiments of the present application;

[0064] FIG. 6 is a sectional view of a protection member according to some other embodiments of the present application;

[0065] FIG. 7 is a sectional view of a protection member according to some other embodiments of the present application;

[0066] FIG. 8 is a top view of a battery monomer according to some embodiments of the present application;

[0067] FIG. 9 is a sectional view of the position A-A in FIG. 8;

[0068] FIG. 10 is a connection schematic diagram of a battery monomer and a thermal insulation pad according to some embodiments of the present application.

[0069] Icon: 10 - case; 11 - first part; 12 - second part; 20 - battery cell; 21 - housing; 211 - casing; 2111 - side wall; 2112 - bottom wall; 212 - end cover; 22 - protector; 221 - main body portion; 222 - first flange portion; 223 - second flange portion; 224 - thermal insulation layer; 225 - insulating layer; 226 - adhesive layer; 23 - electrode assembly; 24 - electrode terminal; 30 - thermal insulation pad; 100 - battery; 200 - controller; 300 - motor; 1000 - vehicle. DETAILED DESCRIPTION

[0070] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0071] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as those commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the present application are only for the purpose of describing the specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion. The terms "first", "second" and the like in the specification and claims of the present application and the above description of drawings are used to distinguish different objects, not to describe a particular order or primary and secondary relationship.

[0072] In the present application, the phrase "embodiment" means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments.

[0073] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection", "attach" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0074] The term "and / or" in the present application is only used to describe the relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the present application generally represents an "or" relationship between the associated objects before and after it.

[0075] In the embodiments of the present application, the same reference signs represent the same components, and for the sake of brevity, the detailed description of the same components is omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device, are only exemplary and should not constitute any limitation on the present application.

[0076] "Multiple" appearing in the present application means two or more (including two).

[0077] In the present application, the battery cell can include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc. The embodiments of the present application are not limited thereto. The battery cell can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, etc. The embodiments of the present application are not limited thereto. The battery cell is generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells, and soft-pack battery cells, etc. The embodiments of the present application are not limited thereto.

[0078] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application can include a battery module or a battery pack, etc. The battery generally includes a box for packaging one or more battery cells. The box can avoid the influence of liquid or other foreign matters on the charging or discharging of the battery cell to some extent.

[0079] A battery cell includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode tab, a negative electrode tab, and a separator. The battery cell mainly works by moving metal ions between the positive electrode tab and the negative electrode tab. The positive electrode tab includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector without the positive electrode active material layer protrudes from the positive electrode current collector with the positive electrode active material layer, and the positive electrode current collector without the positive electrode active material layer serves as a positive electrode tab. Taking a lithium ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate. The negative electrode tab includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector without the negative electrode active material layer protrudes from the negative electrode current collector with the negative electrode active material layer, and the negative electrode current collector without the negative electrode active material layer serves as a negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon. In order to ensure that the fuse does not occur when passing a large current, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. The material of the separator can be PP (polypropylene) or PE (polyethylene).

[0080] At present, from the development of market situation, the application of batteries is more and more widely. Batteries are not only applied to energy storage power systems such as hydroelectric, thermal, wind and solar power stations, but also widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, military equipment, aerospace and other fields. With the continuous expansion of the application field of batteries, the demand of the market is also increasing.

[0081] The development of battery technology needs to consider many design factors, such as battery life, energy density, discharge capacity, charge-discharge rate and other performance parameters. In addition, the reliability of the battery also needs to be considered. However, the reliability of the current battery is poor.

[0082] The battery generally includes a plurality of battery cells and a box body, and the plurality of battery cells are accommodated in the box body. When one battery cell occurs thermal runaway, heat is easily transferred to another battery cell adjacent to the battery cell, thereby causing another battery cell adjacent to the battery cell to also occur thermal runaway, resulting in poor reliability of the battery.

[0083] In view of this, the battery cell provided in the embodiments of the present application includes a shell, an electrode assembly and a protective member, the electrode assembly is contained in the shell. The electrode assembly includes a positive electrode sheet, a separator and a negative electrode sheet, the positive electrode sheet, the separator and the negative electrode sheet are wound or laminated to form the electrode assembly. The protective member covers at least part of the outer surface of the shell, and includes a thermal insulation layer, the thermal insulation layer is used to inhibit the conduction of heat of the electrode assembly to the side of the protective member away from the shell, and the thermal conductivity of the thermal insulation layer is less than or equal to 0.5.

[0084] The battery cell is provided with a protective member, which covers at least part of the outer surface of the shell. The protective member has a thermal insulation layer, by making the thermal conductivity of the thermal insulation layer less than or equal to 0.5, the thermal insulation layer has a good barrier effect on heat, and can effectively inhibit the conduction of heat to the side of the protective member away from the shell. When thermal runaway occurs in one battery cell, the protective member can to some extent prevent heat from being transmitted to another battery cell adjacent to the battery cell, thereby reducing the risk of thermal runaway of another battery cell adjacent to the battery cell, and improving the reliability of the battery.

[0085] The technical solutions described in the embodiments of the present application are suitable for batteries and electric devices using the batteries.

[0086] The electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy and an electric tool, etc. The spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc. The electric toy includes a fixed or mobile electric toy, for example, a game machine, an electric car toy, an electric ship toy and an electric plane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool and a railway electric tool, for example, an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator and an electric planer, etc. The embodiments of the present application do not specially limit the above electric devices.

[0087] The following embodiments take the vehicle 1000 as an example for convenience of description.

[0088] Please refer to FIG. 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile or a range extended automobile, etc. The vehicle 1000 is internally provided with a battery 100, which can be arranged at the bottom, the head or the tail of the vehicle 1000. The battery 100 can be used for power supply of the vehicle 1000, for example, the battery 100 can be used as an operating power source of the vehicle 1000. The vehicle 1000 can further include a controller 200 and a motor 300, the controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the working power demand of the vehicle 1000 during starting, navigation and driving.

[0089] In some embodiments of the present application, the battery 100 can not only serve as the operating power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing the fuel or natural gas to provide driving power for the vehicle 1000.

[0090] Please refer to FIG. 2, which is an exploded view of the battery 100 according to some embodiments of the present application. The battery 100 includes a box body 10 and a battery cell 20, and the battery cell 20 is contained in the box body 10. The box body 10 is used to provide a containing space for the battery cell 20, and the box body 10 can adopt various structures. In some embodiments, the box body 10 can include a first part 11 and a second part 12, and the first part 11 and the second part 12 are mutually covered. The first part 11 and the second part 12 jointly define a containing space for containing the battery cell 20. The second part 12 can be a hollow structure with one end open, and the first part 11 can be a plate-shaped structure, which is covered on the open side of the second part 12 to jointly define the containing space with the second part 12. The first part 11 and the second part 12 can also be hollow structures with one side open, and the open side of the first part 11 is covered on the open side of the second part 12. Of course, the box body 10 formed by the first part 11 and the second part 12 can have various shapes, such as a cylinder, a cuboid, etc.

[0091] In the battery 100, the battery cell 20 can be multiple, and the multiple battery cells 20 can be connected in series, in parallel, or in a mixed connection. The mixed connection means that there are both series connection and parallel connection among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed connection, and then the whole of the multiple battery cells 20 is contained in the box body 10. Of course, the battery 100 can also be that the multiple battery cells 20 are first connected in series, in parallel, or in a mixed connection to form a battery module, and then multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, which is contained in the box body 10. The battery 100 can also include other structures, for example, the battery 100 can also include a current combing component for realizing the electrical connection among the multiple battery cells 20.

[0092] Each battery cell 20 can be a secondary battery cell or a primary battery cell, and can also be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited thereto. The battery cell 20 can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, etc.

[0093] Please refer to FIG. 3, FIG. 4 and FIG. 5, FIG. 3 is an exploded view of the battery cell 20 according to some embodiments of the present application. FIG. 4 is a structural schematic view of the battery cell 20 according to some embodiments of the present application. FIG. 5 is a sectional view of the protective member 22 according to some embodiments of the present application. The embodiments of the present application provide a battery cell 20, which includes a housing 21, an electrode assembly 23 and a protective member 22. The electrode assembly 23 is contained in the housing 21, and the electrode assembly 23 includes a positive electrode sheet, a negative electrode sheet and a separator. The positive electrode sheet, the separator and the negative electrode sheet are wound or stacked to form the electrode assembly. The protective member 22 covers at least a portion of the outer surface of the housing 21, and the protective member 22 includes a thermal insulation layer 224. The thermal insulation layer 224 is used to inhibit the heat of the electrode assembly 23 from being conducted to the side of the protective member 22 away from the housing 21. The thermal conductivity of the thermal insulation layer 224 is less than or equal to 0.5.

[0094] The battery cell 20 refers to the smallest unit that constitutes the battery 100.

[0095] The housing 21 includes an end cap 212 and a shell 211. The shell 211 has an open-ended containing space for containing the electrode assembly 23. The end cap 212 is connected to the shell 211 and closes the opening.

[0096] The end cap 212 refers to a component that covers the opening of the shell 211 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 212 can be adapted to the shape of the shell 211 to fit the shell 211. Alternatively, the end cap 212 can be made of a material with certain hardness and strength, such as aluminum alloy, so that the end cap 212 is not easily deformed when subjected to extrusion and collision, enabling the battery cell 20 to have higher structural strength and the safety performance can also be improved. The material of the end cap 212 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not specially limited by the embodiments of the present application. The battery cell 20 also includes an insulating member arranged on the inner side of the end cap 212. The insulating member can be used to isolate the electrical connection components in the shell 211 from the end cap 212 to reduce the risk of short circuit. Exemplarily, the insulating member can be plastic, rubber, etc. Alternatively, the end cap 212 is also provided with an electrode terminal 24, which is used to electrically connect with the tab of the electrode assembly 23 to input or output the electrical energy of the battery cell 20. The electrode terminal 24 and the tab can be directly connected, such as directly welded. The electrode terminal 24 and the tab can also be indirectly connected, such as indirectly connected through a current collecting member.

[0097] The shell 211 is a component for fitting the end cover 212 to form an internal environment of the battery cell 20, and the formed internal environment can be used to accommodate the electrode assembly 23, the electrolyte, and other components. The shell 211 and the end cover 212 can be independent components, and an opening can be provided on the shell 211, and the end cover 212 is fitted to cover the opening to form the internal environment of the battery cell 20. Without limitation, the end cover 212 and the shell 211 can also be integrated, specifically, the end cover 212 and the shell 211 can form a common joint surface before other components enter the shell, and when it is necessary to seal the internal environment of the shell 211, the end cover 212 is fitted to cover the shell 211. The shell 211 can be various shapes and sizes, such as a cuboid, a cylinder, a hexagonal prism, etc. Specifically, the shape of the shell 211 can be determined according to the specific shape and size of the electrode assembly 23. The material of the shell 211 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the present application does not make special limitations thereto.

[0098] The electrode assembly 23 is a component in which electrochemical reactions occur in the battery cell 20. One or more electrode assemblies 23 can be contained in the shell 21. The electrode assembly 23 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and an insulating film is usually provided between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet and the negative electrode sheet have a portion with active material constituting a main body of the electrode assembly 23, and a portion without active material constituting a tab of each of the positive electrode sheet and the negative electrode sheet. The positive tab and the negative tab can be located together at one end of the main body or respectively at both ends of the main body. During the charging and discharging process of the battery 100, the positive active material and the negative active material react with the electrolyte.

[0099] The protector 22 is a component that covers the outside of the shell 21 to protect the shell 21. The protector 22 can cover a part of the shell 21, and the protector 22 can also completely cover the shell 21.

[0100] The protector 22 includes a heat insulation layer 224, which can inhibit the conduction of heat of the electrode assembly 23 to the side of the protector 22 away from the shell 21. In other words, the heat insulation layer 224 can slow down the conduction of heat to a certain extent. That is, the heat insulation layer 224 has a relatively small thermal conductivity, and heat is not easily conducted through the heat insulation layer 224.

[0101] The thermal conductivity of the heat insulation layer 224 is less than or equal to 0.5, and the thermal conductivity of the heat insulation layer can be 0.5, 0.48, 0.45, 0.42, 0.4, 0.38, 0.35, 0.32, 0.3, 0.28, 0.25, etc.

[0102] The battery cell 20 is provided with a protective member 22, which covers at least part of the outer surface of the shell 21. The protective member 22 has a heat insulation layer 224, which has a thermal conductivity less than or equal to 0.5, has a good heat blocking effect, and can effectively inhibit the conduction of heat to the side of the protective member 22 away from the shell 21. When one battery cell 20 experiences thermal runaway, the protective member 22 can to some extent prevent heat from being transmitted to another battery cell 20 adjacent to the battery cell 20, thereby reducing the risk of thermal runaway of the other battery cell 20 adjacent to the battery cell 20, and improving the reliability of the battery 100.

[0103] In some embodiments, the nickel content of the positive electrode active material of the positive electrode sheet is greater than or equal to 40% and less than 65%, and the melting point of the heat insulation layer 224 is greater than or equal to 150°C.

[0104] In some embodiments, the nickel content of the positive electrode active material of the positive electrode sheet is greater than or equal to 40% and less than 65%, and the melting point of the heat insulation layer 224 is greater than or equal to 150°C.

[0105] When the nickel content of the positive electrode active material of the positive electrode sheet is greater than or equal to 40% and less than 65%, the heat generated by the thermal runaway of the battery cell 20 is relatively large. By making the melting point of the heat insulation layer 224 greater than or equal to 150°C, the heat insulation layer 224 can effectively withstand the high temperature generated by thermal runaway, so that the heat insulation layer 224 is not easily burned through.

[0106] In other embodiments, the nickel content of the positive electrode active material of the positive electrode sheet is greater than or equal to 65%, the melting point of the heat insulation layer 224 is greater than or equal to 500°C, and the thermal conductivity of the heat insulation layer 224 is less than or equal to 0.26.

[0107] In some embodiments, the nickel content of the positive electrode active material of the positive electrode sheet is greater than or equal to 40% and less than 65%, and the melting point of the heat insulation layer 224 is greater than or equal to 150°C.

[0108] When the nickel content of the positive electrode active material of the positive electrode sheet is greater than or equal to 65%, the heat generated by the thermal runaway of the battery cell 20 is larger. By making the melting point of the heat insulation layer 224 greater than or equal to 500°C, the heat insulation layer 224 can more effectively withstand the high temperature generated by thermal runaway, so that the heat insulation layer 224 is not easily burned through. By making the thermal conductivity of the heat insulation layer 224 less than or equal to 0.26, the heat insulation layer 224 has a better heat blocking effect and can more effectively inhibit the conduction of heat to the side of the protective member 22 away from the shell 21.

[0109] Please refer to FIG. 5. In some embodiments, the protective member 22 comprises an insulation layer 225 which is arranged in a stack with the thermal insulation layer 224.

[0110] The insulation layer 225 has insulation properties and can insulate and isolate the shell 21 and other electrically connected components. The material of the insulation layer 225 can be plastic, rubber, etc.

[0111] The insulation layer 225 and the thermal insulation layer 224 are arranged along the thickness direction of the protective member 22. The insulation layer 225 can be closer to the shell 21 than the thermal insulation layer 224, or the thermal insulation layer 224 can be closer to the shell 21 than the insulation layer 225. Please refer to FIG. 5. In the embodiment shown in FIG. 5, the thermal insulation layer 224 is closer to the shell 21 than the insulation layer 225.

[0112] The protective member 22 further comprises the insulation layer 225, so that the protective member 22 has insulation effects and can insulate and isolate the shell 21 and other electrically connected components, thereby reducing the risk of short circuit caused by contact between the shell 21 and other electrically connected components.

[0113] Please refer to FIG. 6, which is a cross-sectional view of the protective member 22 according to some embodiments of the present application. In some embodiments, the protective member 22 comprises a plurality of thermal insulation layers 224, and an insulation layer 225 is arranged between any two adjacent thermal insulation layers 224.

[0114] The protective member 22 can comprise two thermal insulation layers 224, three thermal insulation layers 224, four thermal insulation layers 224, or more than four thermal insulation layers 224. An insulation layer 225 is arranged between any two adjacent thermal insulation layers 224. Please refer to FIG. 6. In the embodiment shown in FIG. 6, the protective member 22 comprises two thermal insulation layers 224 and an insulation layer 225 arranged between the two thermal insulation layers 224.

[0115] The plurality of thermal insulation layers 224 can improve the heat insulation effect of the protective member 22. The insulation layer 225 arranged between any two adjacent thermal insulation layers 224 can prevent the insulation layer 225 from being ablated by high temperature, thereby improving the insulation effect of the protective member 22.

[0116] Please refer to FIG. 6. In some embodiments, the side of the thermal insulation layer 224 facing away from the shell 21 is provided with the insulation layer 225.

[0117] The side of each thermal insulation layer 224 facing away from the shell 21 is provided with the insulation layer 225. In this case, the outermost layer of the protective member 22 is the insulation layer 225. The insulation layer 225 can protect the thermal insulation layer 224. Please refer to FIG. 6. In the embodiment shown in FIG. 6, the protective member 22 comprises two thermal insulation layers 224 and two insulation layers 225, the two thermal insulation layers 224 and the two insulation layers 225 are arranged alternately, and the outermost layer of the protective member 22 facing away from the shell 21 is the insulation layer 225.

[0118] When the side of the thermal insulation layer 224 facing away from the shell 21 is provided with the insulating layer 225, the outermost layer of the protection piece 22 is the insulating layer 225, which can insulate and isolate the thermal insulation layer 224 from other electrical connection components, reducing the risk of the thermal insulation layer 224 conducting the other two electrical connection components. In addition, the insulating layer 225 can protect the thermal insulation layer 224, reducing the risk of damage to the thermal insulation layer 224, so that the protection piece 22 can stably play a heat insulation role. Furthermore, the insulating layer 225 can also support the thermal insulation layer 224, reducing the risk of the thermal insulation layer 224 falling off.

[0119] Please refer to FIG. 5 and FIG. 6, in some embodiments, the protection piece 22 includes one or more insulating layers 225, and the total thickness of the one or more insulating layers 225 is D1, which satisfies: 0.05mm≤D1≤0.1mm.

[0120] Please refer to FIG. 5, when the protection piece 22 includes one insulating layer 225, D1 represents the thickness of the one insulating layer 225. Please refer to FIG. 6, when the protection piece 22 includes multiple insulating layers 225, D1 represents the total thickness of the multiple insulating layers 225. In the embodiment shown in FIG. 6, the protection piece 22 includes two insulating layers 225, the thickness of one insulating layer 225 is D 11 , and the thickness of the other insulating layer 225 is D 12 , then D1=D 11 +D 12 .

[0121] The total thickness of the one or more insulating layers 225 can be: D1=0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, etc.

[0122] When D1≥0.05mm, the total thickness of the one or more insulating layers 225 is large, which has good insulation effect. When D1≤0.1mm, the total thickness of the one or more insulating layers 225 is not too large, on the one hand, it can reduce the occupation of the internal space of the battery 100, which is beneficial to improve the energy density of the battery 100. On the other hand, it can reasonably use the insulating layer 225, reduce unnecessary material consumption, and reduce the cost of the battery monomer 20. Therefore, when 0.05mm≤D1≤0.1mm, the insulation effect and the energy density of the battery 100 can be considered.

[0123] Please refer to FIG. 7, which is a cross-sectional view of the protection piece 22 provided in some embodiments of the present application. In some embodiments, the thermal insulation layer 224 is an insulating material.

[0124] The thermal insulation layer 224 is made of insulating material, and the melting point of the thermal insulation layer 224 is greater than or equal to 150 DEG C, and the thermal conductivity of the thermal insulation layer 224 is less than or equal to 0.26. For example, the material of the thermal insulation layer 224 can be ceramic material.

[0125] The thermal insulation layer 224 is made of insulating material, so that the thermal insulation layer 224 not only has the functions of heat insulation and heat resistance, but also has the function of insulation. In this way, the thermal insulation layer 224 can insulate and isolate the shell 21 from other electrically connected components, thereby reducing the risk of short circuit caused by the contact between the shell 21 and other electrically connected components.

[0126] Please refer to FIG. 5, FIG. 6 and FIG. 7. In some embodiments, the protective member 22 includes one or more thermal insulation layers 224, and the total thickness of the one or more thermal insulation layers 224 is D2, which satisfies: 0.05mm≤D2≤0.3mm.

[0127] Please refer to FIG. 5. When the protective member 22 includes one thermal insulation layer 224, D2 represents the thickness of the thermal insulation layer 224. Please refer to FIG. 6. When the protective member 22 includes multiple thermal insulation layers 224, D2 represents the total thickness of the multiple thermal insulation layers 224. In the embodiment shown in FIG. 6, the protective member 22 includes two thermal insulation layers 224, the thickness of one thermal insulation layer 224 is D 21 , and the thickness of the other thermal insulation layer 224 is D 22 , then D2=D 21 +D 22 .

[0128] The total thickness of the one or more thermal insulation layers 224 can be: D2=0.05mm, 0.08mm, 0.1mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm, etc.

[0129] When D2≥0.05mm, the total thickness of the one or more thermal insulation layers 224 is large, which has good heat insulation effect. When D2≤0.3mm, the total thickness of the one or more thermal insulation layers 224 is not too large, on the one hand, it can reduce the occupation of the internal space of the battery 100, which is beneficial to improve the energy density of the battery 100. On the other hand, it can reasonably use the thermal insulation layer 224, reduce unnecessary material consumption, and reduce the cost of the battery monomer 20. Therefore, when 0.05mm≤D2≤0.3mm, the heat insulation effect and the energy density of the battery 100 can be considered.

[0130] In some embodiments, the material of the shell 21 includes steel material, and satisfies: 0.05mm≤D2≤0.2mm.

[0131] The steel material can be carbon steel, alloy steel or stainless steel, etc. The carbon steel can be low carbon steel, medium carbon steel or high carbon steel. Using carbon steel or stainless steel as the material of the shell 21 has lower cost and is convenient for manufacturing.

[0132] When the material of the shell 21 includes a steel material, the total thickness of the one or more thermal insulation layers 224 can be: D2=0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, etc.

[0133] When the material of the shell 21 includes a steel material, since the thermal conductivity coefficient of the steel material is relatively low, the total thickness of the one or more thermal insulation layers 224 can be set to be relatively small, that is, when the material of the shell 21 includes a steel material, the total thickness of the one or more thermal insulation layers 224 is limited within 0.05-0.2mm, which can better balance the thermal insulation effect and the energy density of the battery 100.

[0134] In other embodiments, the material of the shell 21 includes an aluminum material, and satisfies: 0.2mm≤D2≤0.3mm.

[0135] The aluminum material includes an aluminum alloy. In some embodiments, the aluminum alloy includes the following components with mass percentage: aluminum≥99.6%, copper≤0.05%, iron≤0.35%, magnesium≤0.03%, manganese≤0.03%, silicon≤0.25%, titanium≤0.03%, vanadium≤0.05%, zinc≤0.05%, and other single elements≤0.03%. Such an aluminum alloy belongs to a three-series aluminum, and the aluminum alloy has lower hardness and better forming ability.

[0136] In other embodiments, the aluminum alloy includes the following components with mass percentage: aluminum≥96.7%, 0.05%≤copper≤0.2%, iron≤0.7%, manganese≤1.5%, silicon≤0.6%, zinc≤0.1%, other single element components≤0.05%, and other element components≤0.15%. Such an aluminum alloy belongs to a five-series aluminum, and the shell 21 made of such an aluminum alloy has higher hardness, greater strength and good anti-damage ability.

[0137] When the material of the shell 21 includes an aluminum material, the total thickness of the one or more thermal insulation layers 224 can be: D2=0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, etc.

[0138] When the material of the shell 21 includes aluminum material, since the thermal conductivity of the aluminum material is relatively high, the total thickness of the one or more thermal insulation layers 224 can be set to be relatively large, that is, when the material of the shell 21 includes aluminum material, the total thickness of the one or more thermal insulation layers 224 is limited within 0.2-0.3 mm, which can better balance the thermal insulation effect and the energy density of the battery 100.

[0139] Please refer to FIGS. 5, 6 and 7, in some embodiments, the protective member 22 includes an adhesive layer 226, which is adhered to the outer surface of the shell 21.

[0140] The adhesive layer 226 has adhesion, and is adhered to the outer surface of the shell 21 to achieve the connection of the protective member 22 and the shell 21. In some embodiments, the adhesive layer 226 is arranged on the side of the thermal insulation layer 224 facing the shell 21, and connects the thermal insulation layer 224 and the shell 21.

[0141] The adhesive layer 226 has adhesion, and by arranging the adhesive layer 226, the protective member 22 can be quickly adhered to the outer surface of the shell 21, and the connection of the protective member 22 and the shell 21 is relatively firm, reducing the risk of the protective member 22 separating from the shell 21.

[0142] Please refer to FIGS. 5, 6 and 7, in some embodiments, the thickness of the adhesive layer 226 is D3, which satisfies: 0.01mm≤D3≤0.1mm.

[0143] The thickness of the adhesive layer 226 can be: D3=0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, etc.

[0144] When D3≥0.01mm, the thickness of the adhesive layer 226 is large, which has good adhesion effect. When D3≤0.1mm, the thickness of the adhesive layer 226 is not too large, on the one hand, it can reduce the occupation of the internal space of the battery 100, which is beneficial to improve the energy density of the battery 100. On the other hand, it can reasonably use the adhesive layer 226, reduce unnecessary material consumption, and reduce the cost of the battery monomer 20. Therefore, when 0.01mm≤D3≤0.1mm, the adhesion effect and the energy density of the battery 100 can be balanced.

[0145] In some embodiments, the material of the shell 21 includes steel material, which satisfies: 0.03mm≤D3≤0.1mm.

[0146] When the material of the shell 21 includes a steel material, the thickness of the adhesive layer 226 can be D3=0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, etc.

[0147] When the material of the shell 21 includes a steel material, the outer surface of the shell 21 is relatively smooth, and thus a thicker adhesive layer is needed to achieve adhesion. Therefore, when the material of the shell 21 includes a steel material, the thickness of the adhesive layer 226 is limited to 0.03-0.1mm, which can better balance the adhesion effect and the energy density of the battery 100.

[0148] In some other embodiments, the material of the shell 21 includes an aluminum material, and the following condition is met: 0.01mm≤D3≤0.05mm.

[0149] When the material of the shell 21 includes an aluminum material, the thickness of the adhesive layer 226 can be D3=0.01mm, 0.015mm, 0.02mm, 0.025mm, 0.03mm, 0.035mm, 0.04mm, 0.045mm, 0.05mm, etc.

[0150] When the material of the shell 21 includes an aluminum material, the outer surface of the shell 21 is relatively rough, and thus a thinner adhesive layer can be used to achieve adhesion. Therefore, when the material of the shell 21 includes an aluminum material, the thickness of the adhesive layer 226 is limited to 0.01-0.05mm, which can better balance the adhesion effect and the energy density of the battery 100.

[0151] Please refer to FIG. 8 and FIG. 9. FIG. 8 is a top view of the battery monomer 20 provided in some embodiments of the present application. FIG. 9 is a sectional view of the position A-A in FIG. 8. In some embodiments, the minimum thickness of the shell 21 is H1, and the thickness of the protective member 22 is D, and the following condition is met: 0.7mm≤H1+D≤3mm.

[0152] H1 represents the minimum thickness of the shell 21. In some embodiments, the shell 21 is a square shell, and the thickness of the wall with the largest area of the outer surface in the shell 21 is the minimum thickness of the shell 21. The wall with the largest area of the outer surface in the shell 21 is commonly referred to as a large face, and the thickness of the large face is the minimum thickness of the shell 21.

[0153] D represents the thickness of the protective member 22. When measuring, the thickness of the protective member 22 at different positions can be measured and averaged to obtain the thickness of the protective member 22.

[0154] H1+D represents the sum of the minimum thickness of the shell 21 and the thickness of the protective member 22. The sum of the minimum thickness of the shell 21 and the thickness of the protective member 22 is within 0.7-3mm.

[0155] The sum of the minimum thickness of the shell 21 and the thickness of the protective member 22 can be: H1+D=0.7mm, 1mm, 1.2mm, 1.5mm, 1.7mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, etc.

[0156] Since the shell 21 can also have a certain heat insulation effect, when the shell 21 is thicker, the thickness of the protective member 22 can be set smaller. When the shell 21 is thinner, the thickness of the protective member 22 can be set larger. When H1+D≥0.7mm, the sum of the minimum thickness of the shell 21 and the thickness of the protective member 22 is larger, having a better heat insulation effect. When H1+D≤3mm, the sum of the minimum thickness of the shell 21 and the thickness of the protective member 22 is not too large, on the one hand, the internal space of the battery 100 can be reduced, which is beneficial to improve the energy density of the battery 100. On the other hand, the protective member 22 can be reasonably utilized, reducing unnecessary material consumption and reducing the cost of the battery monomer 20. Therefore, when 0.7mm≤H1+D≤3mm, the heat insulation effect and the energy density of the battery 100 can be considered.

[0157] In some embodiments, 0.1mm≤D≤0.6mm.

[0158] When 0.1mm≤D≤0.6mm, the thickness of the protective member 22 is small, and the protective member 22 is a thin film structure.

[0159] The thickness of the protective member 22 can be: D=0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, etc.

[0160] When D≥0.1mm, the thickness of the protective member 22 is large, and the protective member 22 has high strength and good protection effect. In addition, the thermal insulation layer 224 can be set thicker, having a better heat insulation effect. When D≤0.6mm, the thickness of the protective member 22 is not too large, on the one hand, the internal space of the battery 100 can be reduced, which is beneficial to improve the energy density of the battery 100. On the other hand, the protective member 22 can be reasonably utilized, reducing unnecessary material consumption and reducing the cost of the battery monomer 20. Therefore, when 0.1mm≤D≤0.6mm, the protection effect and the energy density of the battery 100 can be considered.

[0161] In some embodiments, 0.3mm≤H1≤2mm.

[0162] The minimum thickness of the shell 21 can be: H1=0.3mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, etc.

[0163] When H1≥0.3mm, the minimum thickness of the shell 21 is relatively large, the shell 21 has a high strength, and the electrode assembly 23 in the shell 21 is well protected. When H1≤2mm, the minimum thickness of the shell 21 is not too large, on the one hand, the occupation of the internal space of the battery 100 can be reduced, and the energy density of the battery 100 can be improved. On the other hand, the shell 21 can be reasonably utilized, unnecessary material consumption can be reduced, and the cost of the battery monomer 20 can be reduced. Therefore, when 0.3mm≤H1≤2mm, the protection effect and the energy density of the battery 100 can be considered.

[0164] Please refer to FIG. 8 and FIG. 9, the shell 21 includes a shell body 211 and an end cover 212, the shell body 211 is formed with an opening at least one end along the first direction, and the end cover 212 seals the opening. The protection piece 22 includes a main body part 221 and a first flange part 222, the main body part 221 covers the outer surface of the shell body 211, along the first direction, the first flange part 222 is connected to one end of the main body part 221, and the first flange part 222 covers at least a part of the outer surface of the end cover 212.

[0165] Please refer to FIG. 9, the first direction is the Z direction shown in the figure.

[0166] The main body part 221 is the part of the protection piece 22 that covers the outer surface of the shell body 211. The outer surface of the shell body 211 is the surface of the shell body 211 facing away from the accommodation space. The inner surface of the shell body 211 is the surface of the shell body 211 facing the accommodation space. The main body part 221 can completely cover the outer surface of the shell body 211, or can cover a part of the outer surface of the shell body 211. Optionally, the shell body 211 has an outer circumferential surface arranged around the opening, and the main body part 221 completely covers the outer circumferential surface of the shell body 211.

[0167] The first flange part 222 is the flange part of the protection piece 22 that is folded towards the end cover 212. Along the first direction, the first flange part 222 is connected to one end of the main body part 221 close to the end cover 212, and after the first flange part 222 is folded towards the end cover 212 relative to the main body part 221, at least a part of the outer surface of the end cover 212 is covered. The first flange part 222 can cover a part of the end cover 212, or can completely cover the end cover 212. Please refer to FIG. 9, in the embodiment shown in FIG. 9, since the electrode terminal 24 is arranged on the end cover 212, the first flange part 222 can avoid the electrode terminal 24, and the first flange part 222 covers a part of the end cover 212.

[0168] The main body part 221 can be wrapped on the outer surface of the shell 211, and the first flange part 222 can be wrapped on at least part of the outer surface of the end cover 212, so that the protector 22 can wrap the corner position where the end cover 212 and the shell 211 are connected. On the one hand, the corner position where the end cover 212 and the shell 211 are connected can be protected, and on the other hand, the risk of sharp-end discharge can be reduced.

[0169] Please refer to FIGS. 8 and 9. In some embodiments, the width of the first flange part 222 is L1, which satisfies: 2mm≤L1≤20mm.

[0170] The width of the first flange part 222 refers to the distance from the position where the first flange part 222 is connected to the main body part 221 to the end of the first flange part 222 away from the main body part 221. In order to facilitate measurement, the protector 22 can be removed from the shell 21, and the distance from the crease position where the first flange part 222 is connected to the main body part 221 to the end of the first flange part 222 away from the main body part 221 is measured.

[0171] The width of the first flange part 222 can be: L1=2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, etc.

[0172] When L1≥2mm, the width of the first flange part 222 is large, the first flange part 222 can cover a larger area of the outer surface of the end cover 212, improve the protection effect of the protector 22 on the corner position where the end cover 212 and the shell 211 are connected, and further reduce the risk of sharp-end discharge. When L1≤20mm, the width of the first flange part 222 is not too large, so that the first flange part 222 is not easy to interfere with other components on the end cover 212. Therefore, when 2mm≤L1≤20mm, the protection effect and the risk of interference with other components can be considered.

[0173] Please refer to FIGS. 8 and 9. In some embodiments, the shell 211 includes a side wall 2111 and a bottom wall 2112, which are integrally formed. In the first direction, one end of the side wall 2111 is connected to the bottom wall 2112, and the other end of the side wall 2111 encloses an opening. The main body part 221 is wrapped on the outer surface of the side wall 2111. The protector 22 further includes a second flange part 223 connected to the end of the main body part 221 opposite to the first flange part 222 in the first direction. The second flange part 223 covers at least part of the outer surface of the bottom wall 2112.

[0174] The side wall 2111 and the bottom wall 2112 are integrally formed when the shell 211 is provided. The side wall 2111 and the bottom wall 2112 can be integrally formed by stamping or by casting. In the first direction, one end of the side wall 2111 is connected to the bottom wall 2112, and the other end of the side wall 2111 is enclosed to form an opening, and the end cover 212 is connected to the other end of the side wall 2111, and the bottom wall 2112 and the end cover 212 are oppositely arranged.

[0175] The main body part 221 can completely cover the outer surface of the side wall 2111, or can only cover part of the outer surface of the side wall 2111. In the embodiments shown in FIGS. 8 and 9, the main body part 221 completely covers the outer surface of the side wall 2111, thereby improving the heat insulation effect.

[0176] The second flange part 223 is a flange part of the protection piece 22 folded towards the bottom wall 2112. The second flange part 223 is connected to one end of the main body part 221 close to the bottom wall 2112. In the first direction, the first flange part 222 and the second flange part 223 are connected to both ends of the main body part 221, and the first flange part 222 and the second flange part 223 are oppositely arranged.

[0177] After the second flange part 223 is folded towards the bottom wall 2112 relative to the main body part 221, it can cover part of the bottom wall 2112, or can completely cover the bottom wall 2112.

[0178] The main body part 221 can cover the outer surface of the side wall 2111, and the second flange part 223 can cover at least part of the outer surface of the bottom wall 2112, so that the protection piece 22 can cover the corner position where the bottom wall 2112 and the side wall 2111 are connected. On the one hand, it can protect the corner position where the bottom wall 2112 and the side wall 2111 are connected, and on the other hand, it can reduce the risk of sharp-end discharge.

[0179] Please refer to FIGS. 8 and 9. In some embodiments, the width of the second flange part 223 is L2, which satisfies: 2mm≤L2≤20mm.

[0180] The width of the second flange part 223 refers to the distance from the position where the second flange part 223 is connected to the main body part 221 to the end of the second flange part 223 away from the main body part 221. In order to facilitate measurement, the protection piece 22 can be removed from the shell 21, and the distance from the crease position where the second flange part 223 is connected to the main body part 221 to the end of the second flange part 223 away from the main body part 221 can be measured.

[0181] The width of the second flange part 223 can be: L2=2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, etc.

[0182] When L2≥2mm, the width of the second flanging part 223 is large, the second flanging part 223 can cover a larger area of the outer surface of the bottom wall 2112, improve the protection effect of the protection piece 22 on the corner position where the side wall 2111 and the bottom wall 2112 are connected, and further reduce the risk of sharp end discharge. When L2≤20mm, the width of the second flanging part 223 is not too large, which is conducive to reducing material consumption and production cost. Therefore, when 2mm≤L2≤20mm, the protection effect and cost reduction can be considered.

[0183] In some embodiments, the thermal insulation layer 224 comprises at least one of a ceramic material, an asbestos material, a rock wool material, and an aerogel felt material.

[0184] The ceramic material, the asbestos material, the rock wool material, and the aerogel felt material all have good thermal insulation effect, can withstand high temperature, and also have insulation effect, so that the thermal insulation layer 224 can not only withstand heat and insulate heat, but also insulate. In addition, the cost of the ceramic material, the asbestos material, the rock wool material, and the aerogel felt material is relatively low.

[0185] The embodiments of the present application also provide a battery 100 comprising the above-mentioned battery monomer 20.

[0186] Please refer to FIG. 10, which is a connection schematic diagram of the battery monomer 20 and the thermal insulation pad 30 provided by some embodiments of the present application. In some embodiments, the battery 100 comprises a plurality of battery monomers 20, and a thermal insulation pad 30 is arranged between the protection pieces 22 of two adjacent battery monomers 20.

[0187] The battery 100 can comprise two battery monomers 20, three battery monomers 20, four battery monomers 20, or more than four battery monomers 20. The plurality of battery monomers 20 can be arranged along a preset direction.

[0188] The thermal insulation pad 30 has a thermal insulation effect, and is arranged between the protection pieces 22 of two adjacent battery monomers 20 along the preset direction.

[0189] By arranging the thermal insulation pad 30 between the protection pieces 22 of two adjacent battery monomers 20, the heat blocking effect is further improved. When one battery monomer 20 experiences thermal runaway, the protection piece 22 and the thermal insulation piece can both prevent heat from being transmitted to another battery monomer 20 adjacent to the battery monomer 20 to a certain extent, further reducing the risk of thermal runaway of another battery monomer 20 adjacent to the battery monomer 20, and improving the reliability of the battery 100.

[0190] Please refer to FIG. 10, in some embodiments, the thickness of the thermal insulation pad 30 is H2, which satisfies: 1.5mm≤H2≤4mm.

[0191] The thickness of the thermal insulation pad 30 can be H2 = 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3 mm, 3.2 mm, 3.5 mm, 3.8 mm, 4 mm, etc.

[0192] When H2 ≥ 1.5 mm, the thermal insulation pad 30 has a large thickness and good thermal insulation effect. When H2 ≤ 4 mm, the thickness of the thermal insulation pad 30 is not too large, on the one hand, the internal space of the battery 100 can be reduced, and the energy density of the battery 100 can be improved. On the other hand, the thermal insulation pad 30 can be reasonably used, unnecessary material consumption can be reduced, and the cost of the battery monomer 20 can be reduced. Therefore, when 1.5 mm ≤ H2 ≤ 4 mm, the thermal insulation effect and the energy density of the battery 100 can be considered. In addition, due to the presence of the protection piece 22, the thickness of the thermal insulation pad 30 can be relatively reduced, thereby further improving the energy density of the battery 100.

[0193] The application also provides a battery monomer 20, which comprises the battery monomer 20.

[0194] According to some embodiments of the application, please refer to FIGS. 3-9.

[0195] The application provides a battery monomer 20, which comprises an outer shell 21 and a protection piece 22, and the protection piece 22 covers at least part of the outer surface of the outer shell 21. The protection piece 22 comprises a thermal insulation layer 224, the melting point of the thermal insulation layer 224 is greater than or equal to 150°C, and the thermal conductivity of the thermal insulation layer 224 is less than or equal to 0.26. The battery monomer 20 is provided with the protection piece 22, and the protection piece 22 covers at least part of the outer surface of the outer shell 21. The protection piece 22 has the thermal insulation layer 224, on the one hand, the melting point of the thermal insulation layer 224 is greater than or equal to 150°C, which can withstand high temperature. On the other hand, the thermal insulation layer 224 has a thermal conductivity of less than or equal to 0.26, which has a good barrier effect on heat. When one battery monomer 20 has thermal runaway, the protection piece 22 can prevent heat from being transmitted to another battery monomer 20 adjacent to the battery monomer 20 to a certain extent, reducing the risk of thermal runaway of another battery monomer 20 adjacent to the battery monomer 20, and improving the reliability of the battery 100.

[0196] In some embodiments, the protection piece 22 comprises an insulating layer 225, and the insulating layer 225 is arranged in a stack with the thermal insulation layer 224. The protection piece 22 further comprises the insulating layer 225, so that the protection piece 22 has an insulating effect, and the protection piece 22 can insulate and isolate the outer shell 21 from other electrical connection components, reducing the risk of short circuit caused by contact between the outer shell 21 and other electrical connection components.

[0197] In some other embodiments, the thermal insulation layer 224 is made of an insulating material. The thermal insulation layer 224 made of the insulating material not only has the functions of thermal insulation and heat resistance, but also has the function of insulation. In this way, the thermal insulation layer 224 can insulate and isolate the shell 21 from other electrically connected components, thereby reducing the risk of short circuit caused by the contact between the shell 21 and other electrically connected components.

[0198] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, wherein, The battery cell comprises: a shell; an electrode assembly accommodated in the shell, the electrode assembly comprising a positive electrode sheet, a separator and a negative electrode sheet, the positive electrode sheet, the separator and the negative electrode sheet being wound or stacked to form the electrode assembly; a protective member covering at least part of the outer surface of the shell, the protective member comprising a thermal insulation layer, the thermal insulation layer being configured to inhibit heat conduction of the electrode assembly to a side of the protective member away from the shell, the thermal insulation layer having a thermal conductivity less than or equal to 0.

5.

2. The battery cell of claim 1, wherein, The positive electrode active material of the positive electrode sheet has a nickel content greater than or equal to 40% and less than 65%, and the thermal insulation layer has a melting point greater than or equal to 150°C.

3. The battery cell of claim 1, wherein, The positive electrode active material of the positive electrode sheet has a nickel content greater than or equal to 65%, and the thermal insulation layer has a melting point greater than or equal to 500°C and a thermal conductivity less than or equal to 0.

26.

4. The battery cell of any one of claims 1-3, wherein, The protective member comprises an insulating layer, and the insulating layer is arranged in a stacked manner with the thermal insulation layer.

5. The battery cell of claim 4, wherein, The protective member comprises a plurality of thermal insulation layers, and the insulating layer is arranged between any two adjacent thermal insulation layers.

6. The battery cell of claim 4 or 5, wherein, The side of the thermal insulation layer away from the shell is provided with the insulating layer.

7. The battery cell of any one of claims 4-6, wherein, The protective member comprises one or more insulating layers, and the total thickness of the one or more insulating layers is D1, which satisfies 0.05mm≤D1≤0.1mm.

8. The battery cell of any one of claims 1-3, wherein, The thermal insulation layer is made of insulating material.

9. The battery cell of any one of claims 1-8, wherein, The protective member comprises one or more thermal insulation layers, and the total thickness of the one or more thermal insulation layers is D2, which satisfies 0.05mm≤D2≤0.3mm.

10. The battery cell of claim 9, wherein, The material of the shell comprises steel material, and D2 satisfies 0.05mm≤D2≤0.2mm.

11. The battery cell of claim 9, wherein, The material of the shell comprises aluminum material, and D2 satisfies 0.2mm≤D2≤0.3mm.

12. The battery cell of any one of claims 1-11, wherein, The protective member comprises an adhesive layer, and the adhesive layer is bonded to the outer surface of the shell.

13. The battery cell of any one of claims 1-12, wherein, The minimum thickness of the shell is H1, and the thickness of the protective member is D, which satisfies 0.7mm≤H1+D≤3mm.

14. The battery cell of any one of claims 1-13, wherein, The shell comprises a shell body and an end cover, the shell body is formed with an opening at at least one end in a first direction, and the end cover closes the opening. The protective member comprises a main body portion and a first flange portion, the main body portion covers the outer surface of the shell body, and the first flange portion is connected to one end of the main body portion in the first direction, and covers at least part of the outer surface of the end cover.

15. The battery cell of claim 14, wherein, The shell body comprises a side wall and a bottom wall, the side wall and the bottom wall are integrally formed, one end of the side wall is connected to the bottom wall in the first direction, the other end of the side wall encloses the opening, and the main body portion covers the outer surface of the side wall. The protective member further comprises a second flange portion, the second flange portion is connected to the other end of the main body portion opposite to the first flange portion in the first direction, and covers at least part of the outer surface of the bottom wall.

16. The battery cell of any one of claims 1-15, wherein, The thermal insulation layer comprises at least one of ceramic material, asbestos material, rock wool material and aerogel felt material.

17. A battery, wherein, The battery comprises a plurality of battery cells according to any one of claims 1-16.

18. The battery of claim 17, wherein, The battery comprises a plurality of battery cells, and a thermal insulation pad is arranged between the protective members of any two adjacent battery cells.

19. The battery of claim 18, wherein, The thickness of the thermal insulation pad is H2, and 1.5mm≤H2≤4mm is met.

20. An electrical device, comprising: The battery cell according to any one of claims 1-16 is used to provide electric energy for the electric device.

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