Secondary battery and electric device

Abstract

The invention discloses a secondary battery and electric equipment. The secondary battery comprises a shell, an electrode assembly and a first insulating part, the electrode assembly comprises a first pole piece, the first pole piece is provided with a first electrode end, the first pole piece is provided with a first edge in the first direction, the second pole piece is provided with a second edge, the second edge exceeds the first edge, and the first electrode end is connected with the first edge and exceeds the second edge. Along the first direction, the parts of the first electrode end and the electrode assembly between the first edge and the second edge are first parts, and the parts of the first electrode end and the electrode assembly between the first edge and the second edge are second parts. In the second direction, the total thickness of the first part is smaller than that of the second part, the projection of the first insulating part covers the projection of the part, exceeding the second edge, of the first electrode end, and the projection of the first insulating part is separated from the projection of the first edge. Through the secondary battery provided by the invention, the risk of short circuit can be reduced, and the loss of energy density can be reduced.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a secondary battery and electrical equipment. Background Art

[0002] In the prior art, a steel shell battery includes a shell and an electrode assembly contained in the shell, wherein the anode tab is electrically connected to the shell after being folded, and the cathode tab is connected to the pole through a adapter after being folded, wherein the pole is insulated from the shell.

[0003] However, when the steel-shell battery is thinner, the distance between the cathode tab and the adapter and the outer shell is shorter. If the steel-shell battery falls or vibrates, the cathode tab and the adapter are likely to contact the outer shell, causing a short circuit. Summary of the invention

[0004] In view of this, the present application provides a secondary battery and an electrical device, which are helpful in reducing the risk of short circuit.

[0005] In a first aspect, the present application provides a secondary battery, comprising a housing, an electrode assembly and a first insulating member. The housing is provided with a receiving cavity, the electrode assembly is provided in the receiving cavity, and the first insulating member is provided on the shell wall inside the housing. The electrode assembly comprises a first pole piece, a second pole piece and a diaphragm, the first pole piece and the second pole piece have opposite polarities, and the diaphragm is provided between the first pole piece and the second pole piece. The first pole piece is provided with a first electrode terminal, and the first electrode terminal is insulated and connected to the housing. Along a first direction, the first pole piece has a first edge, the second pole piece has a second edge, the second edge exceeds the first edge, and the first electrode terminal connects the first edge and exceeds the second edge. Along the first direction, the first electrode terminal and the portion of the electrode assembly located between the first edge and the second edge are the first portion, and the first electrode terminal and the portion of the electrode assembly located at the first edge away from the second edge are the second portion. Along the second direction, the total thickness of the first portion is less than the total thickness of the second portion. Along the second direction, the projection of the first insulating member covers the projection of the portion of the first electrode terminal exceeding the second edge, and the projection of the first insulating member is separated from the projection of the first edge. The second direction is the thickness direction of the electrode assembly. The second direction is perpendicular to the first direction.

[0006] Along the second direction, the projection of the first insulating member covers the projection of the portion of the first electrode end that exceeds the second edge. When a fall or vibration occurs, the first insulating member helps reduce the risk of the first electrode end contacting the housing along the second direction, thereby helping to reduce the risk of a short circuit. Along the second direction, the total thickness of the first portion is less than the total thickness of the second portion, and the projection of the first insulating member is separated from the projection of the first edge. In this way, the first insulating member can use the extra thickness space of the first portion along the second direction compared to the second portion, which helps to reduce the thickness space that needs to be reserved in the secondary battery due to the provision of the first insulating member, thereby helping to reduce the loss of energy density in the secondary battery.

[0007] In one or more of the above embodiments, the material of the first insulating member includes at least one of polypropylene, silicone rubber, fluororubber, polyvinyl chloride, polyethylene terephthalate, polycarbonate and nylon.

[0008] In the above embodiment, the first insulating member can be made into a gel-like shape and bonded to the shell, which is beneficial to improve the stability of the first insulating member remaining fixed to the shell under long-term corrosion of the electrolyte, thereby helping to further reduce the risk of short circuit.

[0009] In one or more of the above embodiments, along the second direction, the thickness of the first insulating member is 5 μm to 200 μm.

[0010] In the above embodiment, the first insulating member not only satisfies the required insulation effect between the first electrode terminal and the housing, but also is not too thick, which is beneficial to further reduce the loss of energy density in the secondary battery.

[0011] In one or more of the above embodiments, the material of the first insulating member includes at least one of ceramic coating, polytetrafluoroethylene, epoxy resin, fluorinated ethylene propylene and polyvinylidene fluoride.

[0012] In the above embodiment, the first insulating member can be coated on the outer shell and fixed, which is conducive to thinning the first insulating member. Therefore, when the number of layers of the first pole sheet and the first pole ear along the second direction is small, resulting in a smaller surplus thickness space of multiple first pole ears stacked along the second direction compared to the first pole sheet, it is still possible to reduce the thickness space along the second direction that needs to be additionally reserved in the secondary battery due to the provision of the first insulating member, which is conducive to reducing the loss of energy density in the secondary battery.

[0013] In one or more of the above embodiments, along the second direction, the thickness of the first insulating member is 1 μm to 50 μm.

[0014] In the above embodiment, the risk of failure of the first insulating member due to processing technology or electrolyte corrosion is reduced, and the first insulating member is not too thick, which is conducive to further reducing the loss of energy density in the secondary battery.

[0015] In one or more of the above embodiments, the housing includes a first wall provided with a first insulating member, and along the second direction, the shortest distance between the first electrode end and the first wall is d, and d≤2 mm.

[0016] In the above embodiment, when a fall or vibration occurs, the first electrode end is more likely to contact the housing along the second direction, and the risk of a short circuit can be better reduced by the first insulating member.

[0017] In one or more of the above embodiments, the secondary battery includes a pole and a second insulating member, the pole is electrically connected to the first electrode terminal and passes through the shell, and the second insulating member is provided on the shell and is configured to insulate the pole from the shell. The second insulating member includes a first insulating portion and a second insulating portion, along the second direction, the first insulating portion is closer to the first insulating portion than the second insulating portion, and a projection of the first insulating member at least partially overlaps with a projection of the first insulating portion.

[0018] In the above embodiment, when a fall or vibration occurs, the first electrode end may be offset along the first direction, and the first electrode end may contact the outer shell through the gap between the pole and the outer shell, and the projection of the first insulating member at least partially overlaps with the projection of the first insulating portion. In this way, the first insulating member is at least partially located between the pole and the outer shell along the second direction, which helps to further reduce the risk of short circuit.

[0019] In one or more of the above embodiments, the secondary battery includes a third insulating member, and the third insulating member is disposed on a side of the first electrode terminal facing the first insulating member.

[0020] In the above embodiment, when a fall or vibration occurs, the first insulating member can preferentially contact the third insulating member rather than directly contact the first electrode terminal. If the first insulating member is thin, it is helpful to reduce the risk of the burr of the first electrode terminal piercing the first insulating member; the third insulating member can separate the shell and the first electrode terminal along the second direction. If the electrode assembly is offset, it is helpful to reduce the possibility of direct contact between the shell and the first electrode terminal. In this way, the risk of short circuit is further reduced.

[0021] In one or more of the above embodiments, the first electrode terminal includes a first electrode tab connected to the first edge, and in the first part, the first electrode tab includes a metal layer and an insulating layer, and the insulating layer is relatively arranged on both sides of the metal layer along the thickness direction of the metal layer. The first pole piece includes a first current collector and a first active material layer, and the first active material layer is relatively arranged on both sides of the first current collector along the thickness direction of the first current collector. The metal layer is electrically connected to the first current collector and extends out of the first current collector along the first direction. Along the second direction, the projection of the insulating layer overlaps with the projection of the second pole piece.

[0022] In the above embodiment, the insulating layer is helpful to reduce the possibility of the metal layer piercing the diaphragm, causing the metal layer to contact the second pole piece, which is helpful to reduce the risk of short circuit. In addition, along the second direction, the projection of the insulating layer overlaps with the projection of the second pole piece, which is helpful to further reduce the risk of short circuit.

[0023] In one or more of the above embodiments, the first electrode terminal includes a first electrode tab connected to the first edge, and in the first part, the first electrode tab includes a metal layer and an insulating layer, and the insulating layer is relatively arranged on both sides of the metal layer along the thickness direction of the metal layer. The first pole piece includes a first current collector and a first active material layer, and the first active material layer is relatively arranged on both sides of the first current collector along the thickness direction of the first current collector. The metal layer is electrically connected to the first current collector and extends out of the first current collector along the first direction. Along the second direction, the thickness of the insulating layer is less than the thickness of the first active material layer.

[0024] In the above embodiment, the insulating layer is helpful to reduce the possibility of the metal layer piercing the diaphragm, causing the metal layer to contact the second pole piece, which is helpful to reduce the risk of short circuit. In addition, along the second direction, the thickness of the insulating layer is less than the thickness of the first active material layer, and the first insulating member can use the extra thickness space of the insulating layer along the second direction compared with the first active material layer, which is helpful to reduce the thickness space along the second direction that needs to be reserved in the secondary battery due to the provision of the first insulating member, thereby helping to reduce the loss of energy density in the secondary battery.

[0025] The second aspect of the present application provides an electric device, comprising the secondary battery described in the first aspect of the present application. The secondary battery is conducive to reducing the risk of short circuit, which is conducive to improving the stability of the operation of the electric device. The loss of energy density in the secondary battery is low, which is conducive to improving the endurance of the electric device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 An overall schematic diagram of a secondary battery provided in one embodiment of the present application.

[0027] Figure 2 A schematic cross-sectional structure diagram of a secondary battery provided in the first embodiment of the present application.

[0028] Figure 3 for Figure 2 Magnified view of area A.

[0029] Figure 4 A schematic cross-sectional structure diagram of a secondary battery provided in the second embodiment of the present application.

[0030] Figure 5 A schematic cross-sectional structure diagram of a secondary battery provided in the third embodiment of the present application.

[0031] Figure 6A schematic diagram of an electrical device provided in one embodiment of the present application.

[0032] Main component symbols 1000, electrical equipment; 100, secondary battery; 10, housing; 101, receiving cavity; 102, first part; 103, second part; 11, housing; 111, bottom wall; 112, side wall; 12, cover; 121, first wall; 20, electrode assembly; 201, first edge; 202, second edge; 21, first pole piece; 211, first current collector; 212, first active material layer; 22. Second pole piece; 221. Second current collector; 222. Second active material layer; 23. Diaphragm; 24. First electrode terminal; 241. First pole ear; 2411. Metal layer; 2412. Insulating layer; 242. Pole ear bundle; 243. Adapter; 25. Single-sided pole piece; 251. Third current collector; 252. Third active material layer; 30. First insulating member; 40. Pole column; 50. Second insulating member; 51. First insulating portion; 52. Second insulating portion; 60. Third insulating member; 70. Fourth insulating member; X, first direction; Y, second direction. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0034] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be a centrally disposed element at the same time. When an element is considered to be "disposed on" another element, it may be directly disposed on the other element or there may be a centrally disposed element at the same time.

[0035] Unless otherwise specified, the term "plurality" as used herein means two or more than two.

[0036] The terms "first", "second", etc. are only used to distinguish different objects and shall not be understood as indicating or implying relative importance or implying the quantity, specific order or primary and secondary relationship of the indicated technical features.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0038] It should be understood that, considering the actual processing tolerance factors, in the technical solution of the present application, when the two elements are arranged parallel / vertically and in the same direction, there may be a certain angle between the two elements, and a tolerance of 0-±10% is allowed between the two elements. A tolerance of 0-±10% is allowed between the two elements greater than, equal to or less than.

[0039] The embodiment of the present application provides a secondary battery, including a shell, an electrode assembly and a first insulating member. The shell is provided with a receiving cavity, the electrode assembly is provided in the receiving cavity, and the first insulating member is provided on the shell wall inside the shell. The electrode assembly includes a first pole piece, a second pole piece and a diaphragm, the polarity of the first pole piece and the second pole piece is opposite, and the diaphragm is provided between the first pole piece and the second pole piece. The first pole piece is provided with a first electrode terminal, and the first electrode terminal is insulated and connected to the shell. Along the first direction, the first pole piece has a first edge, the second pole piece has a second edge, the second edge exceeds the first edge, and the first electrode terminal connects the first edge and exceeds the second edge. Along the first direction, the first electrode terminal and the portion of the electrode assembly located between the first edge and the second edge are the first portion, and the first electrode terminal and the portion of the electrode assembly located at the first edge away from the second edge are the second portion. Along the second direction, the total thickness of the first portion is less than the total thickness of the second portion. Along the second direction, the projection of the first insulating member covers the projection of the portion of the first electrode terminal exceeding the second edge, and the projection of the first insulating member is separated from the projection of the first edge. The second direction is the thickness direction of the electrode assembly. The second direction is perpendicular to the first direction.

[0040] Along the second direction, the projection of the first insulating member covers the projection of the portion of the first electrode end that exceeds the second edge. When a fall or vibration occurs, the first insulating member helps reduce the risk of the first electrode end contacting the housing along the second direction, thereby helping to reduce the risk of a short circuit. Along the second direction, the total thickness of the first portion is less than the total thickness of the second portion, and the projection of the first insulating member is separated from the projection of the first edge. In this way, the first insulating member can use the extra thickness space of the first portion along the second direction compared to the second portion, which helps to reduce the thickness space that needs to be reserved in the secondary battery due to the provision of the first insulating member, thereby helping to reduce the loss of energy density in the secondary battery.

[0041] Some embodiments of the present application will be described below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0042] Please refer to Figure 1 and Figure 2 An embodiment of the present application provides a secondary battery 100 including a housing 10 , an electrode assembly 20 and a first insulating member 30 .

[0043] The housing 10 is provided with a receiving cavity 101. In some embodiments, the housing 10 includes a shell 11 and a shell cover 12, the shell 11 is recessed in a direction away from the shell cover 12, and the shell cover 12 is connected to the shell 11 to form the receiving cavity 101.

[0044] In some embodiments, the housing 11 includes a bottom wall 111 and a side wall 112 . The side wall 112 is disposed around the periphery of the bottom wall 111 , and the housing cover 12 covers the side wall 112 .

[0045] In some embodiments, the housing 10 is made of steel.

[0046] The electrode assembly 20 is disposed in the receiving cavity 101. The electrode assembly 20 includes a first electrode piece 21, a second electrode piece 22, and a diaphragm 23. The first electrode piece 21 and the second electrode piece 22 have opposite polarities, and the diaphragm 23 is disposed between the first electrode piece 21 and the second electrode piece 22. In some embodiments, the receiving cavity 101 is filled with an electrolyte to facilitate the formation of a current loop between the first electrode piece 21 and the second electrode piece 22.

[0047] In some embodiments, the first pole piece 21 is a cathode pole piece, and the second pole piece 22 is an anode pole piece.

[0048] In some embodiments, the electrode assembly 20 is a stacked structure, which is formed by alternating the first pole piece 21 and the second pole piece 22, and the separator 23 is arranged between the adjacent first pole piece 21 and the second pole piece 22. In some embodiments, the electrode assembly 20 is a wound structure, which is formed by stacking the first pole piece 21, the separator 23 and the second pole piece 22 in sequence and then winding them.

[0049] In some embodiments, along the second direction Y, the projection of the diaphragm 23 covers the projection of the first pole piece 21 and the projection of the second pole piece 22. This is beneficial to reduce the risk of short circuit caused by contact between the first pole piece 21 and the second pole piece 22. The second direction Y is the thickness direction of the electrode assembly 20. The second direction Y is perpendicular to the first direction X.

[0050] The first electrode piece 21 is provided with a first electrode terminal 24, the first electrode terminal 24 extends out of the first electrode piece 21 along the first direction X, and the first electrode terminal 24 is insulated and connected to the housing 10. In some embodiments, the second electrode piece 22 is provided with a second electrode terminal (not shown), and the second electrode terminal is electrically connected to the housing 10. In some embodiments, the first electrode terminal 24 is insulated and connected to the side wall 112 of the housing 11, and the second electrode terminal is electrically connected to the housing cover 12.

[0051] See also Figure 2, along the first direction X, the first electrode piece 21 has a first edge 201, and the second electrode piece 22 has a second edge 202. Along the first direction X, the second edge 202 exceeds the first edge 201, the first electrode end 24 is connected to the first edge 201, and the first electrode end 24 exceeds the second edge 202. Along the first direction X, the first electrode end 24 and the portion of the electrode assembly 20 located between the first edge 201 and the second edge 202 are the first portion 102, and the first electrode end 24 and the portion of the electrode assembly 20 located at the first edge 201 away from the second edge 202 are the second portion 103. Along the second direction Y, the total thickness of the first portion 102 is less than the total thickness of the second portion 103.

[0052] It should be noted that the total thickness of the first part 102 along the second direction Y refers to the maximum actual thickness of the first electrode end 24, the second electrode piece 22 and the diaphragm 23 of the first part 102 along the second direction Y, and the total thickness of the second part 103 along the second direction Y refers to the maximum actual thickness of the first electrode piece 21, the second electrode piece 22 and the diaphragm 23 of the second part 103 along the second direction Y.

[0053] In some embodiments, see Figure 3 The first pole piece 21 includes a first current collector 211 and a first active material layer 212. Along the thickness direction of the first current collector 211, the first active material layer 212 is relatively arranged on both sides of the first current collector 211. The second pole piece 22 includes a second current collector 221 and a second active material layer 222. Along the first direction X, the second active material layer 222 is arranged on both sides of the second current collector 221. In some embodiments, the thickness direction of the first current collector 211 is parallel to the second direction Y.

[0054] In some embodiments, along the second direction Y, the separator 23 is disposed between the first active material layer 212 and the second active material layer 222 .

[0055] In some embodiments, see Figure 2 The first electrode terminal 24 includes a plurality of first electrode tabs 241, and the first electrode tabs 241 are connected to the first edge 201. In the first portion 102, the first electrode tabs 241 include a metal layer 2411 and an insulating layer 2412 (see Figure 3 ), along the thickness direction of the metal layer 2411, the insulating layer 2412 is relatively arranged on both sides of the metal layer 2411. The insulating layer 2412 is helpful to reduce the possibility of the metal layer 2411 piercing the diaphragm 23, causing the metal layer 2411 to contact the second pole piece 22, which is helpful to reduce the risk of short circuit. In some embodiments, the thickness direction of the metal layer 2411 is parallel to the second direction Y.

[0056] In some embodiments, along the second direction Y, the thickness of the first pole tab 241 is less than the thickness of the first pole piece 21 .

[0057] In some embodiments, along the second direction Y, the projection of the insulating layer 2412 overlaps with the projection of the second pole piece 22. This is beneficial to further reduce the possibility that the metal layer 2411 pierces the diaphragm 23, causing the metal layer 2411 to contact the second pole piece 22, and is beneficial to further reduce the risk of short circuit.

[0058] In some embodiments, the metal layer 2411 is electrically connected to the first current collector 211 , and the metal layer 2411 extends out of the first current collector 211 along the first direction X.

[0059] In some embodiments, the metal layer 2411 is welded or riveted to the first current collector 211. With the first edge 201 as the boundary, the metal layer 2411 includes a fixing portion (not shown) and an extension portion (not shown), the fixing portion is welded or riveted to the first current collector 211, and the extension portion is connected to the fixing portion and extends out of the first edge 201 along the first direction X. In some embodiments, the metal layer 2411 and the first current collector 211 are made of different materials.

[0060] In some embodiments, the metal layer 2411 is integrally formed with the first current collector 211. For example, the metal layer 2411 and the first current collector 211 are die-cut on a sheet, and the metal layer 2411 is directly connected to the first edge 201. In some embodiments, the metal layer 2411 and the first current collector 211 are made of the same material.

[0061] In some embodiments, see Figure 2 The first electrode terminal 24 includes a tab bundle 242, and a plurality of first tabs 241 are gathered in the tab bundle 242. In other embodiments, a plurality of first tabs 241 are stacked in sequence along the second direction Y and welded to form the tab bundle 242.

[0062] In some embodiments, after the tab bundle 242 gathers the plurality of first tabs 241 in a direction away from the first insulating member 30 , the tab bundle 242 bends and extends in a direction toward the first insulating member 30 .

[0063] In some embodiments, see Figure 2 The first electrode terminal 24 includes a transition piece 243, and the transition piece 243 is connected to the tab bundle 242. In some embodiments, the transition piece 243 is connected to a section of the tab bundle 242 extending toward the first insulating member 30.

[0064] In some embodiments, the adapter 243 is connected to the tab bundle 242 by welding.

[0065] In some embodiments, after the adapter 243 is connected to the tab bundle 242 , it extends and bends in a direction toward the first insulating member 30 , and the bent tab bundle 242 extends in a direction away from the first insulating member 30 .

[0066] In some embodiments, the material of the adapter 243 is one or more conductive materials such as copper, aluminum, nickel, and nickel alloy.

[0067] See also Figure 2 , the first insulating member 30 is disposed on the shell wall inside the shell 10. In some embodiments, the first insulating member 30 is disposed on the shell cover 12.

[0068] Along the second direction Y, the projection of the first insulating member 30 covers the projection of the portion of the first electrode terminal 24 that exceeds the second edge 202. When a fall or vibration occurs, the first insulating member 30 helps reduce the risk of the first electrode terminal 24 contacting the housing 10 along the second direction Y, thereby helping to reduce the risk of a short circuit.

[0069] Along the second direction Y, the projection of the first insulating member 30 is separated from the projection of the first edge 201. Since the total thickness of the first portion 102 along the second direction Y is less than the total thickness of the second portion 103, the first insulating member 30 can utilize the extra thickness space of the first portion 102 compared to the second portion 103 along the second direction Y, which is beneficial to reduce the thickness space along the second direction Y that needs to be additionally reserved in the secondary battery 100 due to the provision of the first insulating member 30, thereby facilitating the reduction of the energy density loss in the secondary battery 100.

[0070] In some embodiments, the thickness of the insulating layer 2412 is less than the thickness of the first active material layer 212 along the second direction Y. The first insulating member 30 can utilize the extra thickness space of the insulating layer 2412 compared with the first active material layer 212 along the second direction Y, which is beneficial to reduce the thickness space along the second direction Y that needs to be additionally reserved in the secondary battery 100 due to the provision of the first insulating member 30, thereby facilitating the reduction of the energy density loss in the secondary battery 100.

[0071] In some embodiments, the material of the first insulating member 30 includes at least one of polypropylene, silicone rubber, fluororubber, polyvinyl chloride, polyethylene terephthalate, polycarbonate and nylon. In this case, the first insulating member 30 can be made into a glue-like material and bonded to the housing 10, which is beneficial to improve the stability of the first insulating member 30 being fixed to the housing 10 under the long-term corrosion state of the electrolyte, thereby further reducing the risk of short circuit.

[0072] In some embodiments, the material of the first insulating member 30 includes at least one of a ceramic coating, polytetrafluoroethylene, epoxy resin, fluorinated ethylene propylene and polyvinylidene fluoride. In this case, the first insulating member 30 can be applied to the housing 10 for fixing, which is conducive to thinning the first insulating member 30, so that when the number of layers of the first pole piece 21 and the first pole ear 241 along the second direction Y is small, resulting in a smaller surplus thickness space of the first pole ears 241 stacked along the second direction Y than the first pole piece 21, it can still reduce the thickness space along the second direction Y that needs to be reserved in the secondary battery 100 due to the provision of the first insulating member 30, which is conducive to reducing the loss of energy density in the secondary battery 100.

[0073] In some embodiments, at a temperature of 60° C. to 100° C., for example, at a temperature of 60° C., 70° C., 80° C., 90° C. or 100° C., the first insulating member 30 remains fixed to the housing 10 after being immersed in the electrolyte for two hours. Preferably, at a temperature of 85° C., the first insulating member 30 remains fixed to the housing 10 after being immersed in the electrolyte for seven days.

[0074] In some embodiments, at a temperature of 85° C., the impedance value of the first insulating member 30 changes by less than 80% before and after being immersed in the electrolyte for seven days. Preferably, the impedance value of the first insulating member 30 changes by less than 20%. In this case, the first insulating member 30 has good corrosion resistance, which is conducive to improving the effectiveness of the first insulating member 30 in maintaining insulation between the housing 10 and the first electrode terminal 24.

[0075] In some embodiments, the material of the first insulating member 30 includes at least one of polypropylene, silicone rubber, fluororubber, polyvinyl chloride, polyethylene terephthalate, polycarbonate and nylon. Along the second direction Y, the thickness of the first insulating member 30 is greater than or equal to 5 μm. This is beneficial for the first insulating member 30 to meet the required insulation effect between the first electrode terminal 24 and the housing 10.

[0076] In some embodiments, the material of the first insulating member 30 includes polypropylene, and along the second direction Y, the thickness of the first insulating member 30 is greater than or equal to 10 μm.

[0077] In some embodiments, the material of the first insulating member 30 includes at least one of polypropylene, silicone rubber, fluororubber, polyvinyl chloride, polyethylene terephthalate, polycarbonate and nylon. Along the second direction Y, the thickness of the first insulating member 30 is 5 μm to 500 μm. For example, the thickness of the first insulating member 30 is 5 μm, 10 μm, 20 μm, 50 μm, 100 μm, 150 μm, 200 μm, 300 μm, 400 μm or 500 μm.

[0078] In some embodiments, the material of the first insulating member 30 includes at least one of polypropylene, silicone rubber, fluororubber, polyvinyl chloride, polyethylene terephthalate, polycarbonate and nylon. Along the second direction Y, the thickness of the first insulating member 30 is 5 μm to 200 μm. In this case, the first insulating member 30 not only satisfies the required insulation effect between the first electrode terminal 24 and the housing 10, but also is not too thick, which is conducive to further reducing the loss of energy density in the secondary battery 100.

[0079] In some embodiments, the material of the first insulating member 30 includes at least one of ceramic coating, polytetrafluoroethylene, epoxy resin, fluorinated ethylene propylene and polyvinylidene fluoride. Along the second direction Y, the thickness of the first insulating member 30 is greater than or equal to 0.1 μm. This is beneficial to reduce the possibility of burrs in the microstructure piercing the first insulating member 30.

[0080] In some embodiments, the material of the first insulating member 30 includes a ceramic coating, and along the second direction Y, the thickness of the first insulating member 30 is greater than or equal to 0.1 μm.

[0081] In some embodiments, the material of the first insulating member 30 includes at least one of ceramic coating, polytetrafluoroethylene, epoxy resin, fluorinated ethylene propylene and polyvinylidene fluoride. Along the second direction Y, the thickness of the first insulating member 30 is 0.1 μm to 200 μm. For example, the thickness of the first insulating member 30 is 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 50 μm, 100 μm or 200 μm.

[0082] In some embodiments, the material of the first insulating member 30 includes at least one of a ceramic coating, polytetrafluoroethylene, epoxy resin, fluorinated ethylene propylene and polyvinylidene fluoride. Along the second direction Y, the thickness of the first insulating member 30 is 1 μm to 50 μm. In this case, it is helpful to reduce the risk of failure of the first insulating member 30 due to factors such as processing technology or electrolyte corrosion, and the first insulating member 30 is not too thick, which is helpful to further reduce the loss of energy density in the secondary battery 100.

[0083] In some embodiments, see Figure 2 , the housing 10 includes a first wall 121 provided with a first insulating member 30, and along the second direction Y, the shortest distance between the first electrode end 24 and the first wall 121 is d, d≤2mm. For example, d is 0.5mm, 1mm, 1.5mm or 2mm. In this case, when a fall or vibration occurs, the first electrode end 24 is more likely to contact the housing 10 along the second direction Y, and the risk of a short circuit can be better reduced by the first insulating member 30.

[0084] In some embodiments, the first wall 121 is located on the housing cover 12 , and the first insulating member 30 is disposed on a side of the housing cover 12 facing the receiving cavity 101 .

[0085] In some embodiments, the shortest distance between the first electrode end 24 and the first wall 121 along the second direction Y refers to the minimum value of the shortest distance between the first electrode tab 241 and the first wall 121 along the second direction Y, the shortest distance between the electrode tab bundle 242 and the first wall 121 along the second direction Y, and the shortest distance between the adapter 243 and the first wall 121 along the second direction Y.

[0086] In some embodiments, see Figure 3 The secondary battery 100 includes a pole 40, which is electrically connected to the first electrode terminal 24 and passes through the housing 10. In some embodiments, the pole 40 is connected to a section of the adapter 243 away from the tab bundle 242, the pole 40 passes through the side wall 112 of the housing 11, and the pole 40 is insulated from the housing 10.

[0087] In some embodiments, along the second direction Y, there is a gap between the pole 40 and the housing 10. In some embodiments, along the second direction Y, there is a gap between the pole 40 and the first wall 121.

[0088] In some embodiments, the secondary battery 100 includes a second insulating member 50, which is disposed on the housing 10 and is configured to insulate the pole 40 from the housing 10. In some embodiments, the second insulating member 50 is disposed on the side wall 112 of the housing 11. Along the first direction X and the second direction Y, at least a portion of the second insulating member 50 is located between the pole 40 and the side wall 112.

[0089] In some embodiments, see Figure 4 The second insulating member 50 includes a first insulating portion 51 and a second insulating portion 52. Along the second direction Y, the first insulating portion 51 is closer to the first insulating member 30 than the second insulating portion 52, and the projection of the first insulating member 30 at least partially overlaps with the projection of the first insulating portion 51. When a fall or vibration occurs, the first electrode terminal 24 may be offset along the first direction X, and the first electrode terminal 24 may contact the housing 10 through the gap between the pole 40 and the housing 10 (such as the housing cover 12), and the projection of the first insulating member 30 at least partially overlaps with the projection of the first insulating portion 51. In this way, the first insulating member 30 is at least partially located between the pole 40 and the housing 10 along the second direction Y, which is conducive to further reducing the risk of short circuit.

[0090] In some embodiments, along the second direction Y, the projection of the adapter 243 at least partially overlaps with the projection of the second insulating portion 52. When a fall or vibration occurs, it is helpful to reduce the possibility of a section of the adapter 243 away from the tab bundle 242 contacting the housing 10 (such as the bottom wall 111 of the housing 11), further reducing the risk of a short circuit.

[0091] In some embodiments, see Figure 5 The secondary battery 100 includes a third insulating member 60, which is disposed on the side of the first electrode terminal 24 facing the first insulating member 30. When a fall or vibration occurs, the first insulating member 30 may preferentially contact the third insulating member 60 rather than directly contact the first electrode terminal 24. If the first insulating member 30 is thin, it is helpful to reduce the risk of the burr of the first electrode terminal 24 piercing the first insulating member 30; the third insulating member 60 can separate the housing 10 and the first electrode terminal 24 along the second direction Y. If the electrode assembly 20 is offset, it is helpful to reduce the possibility of direct contact between the housing 10 and the first electrode terminal 24. In this way, the risk of short circuit is further reduced.

[0092] In some embodiments, along the second direction Y, the projection of the third insulating member 60 covers the projection of the first electrode terminal 24 , and the projection of the third insulating member 60 at least partially overlaps with the projection of the first insulating member 30 .

[0093] In some embodiments, the third insulating member 60 is contoured with the first electrode terminal 24 , which is beneficial to reducing the space occupied by the third insulating member 60 and the first electrode terminal 24 in the receiving cavity 101 and improving the energy density of the secondary battery 100 .

[0094] In some embodiments, the third insulating member 60 is fixed to the outermost pole piece of the electrode assembly 20 facing the first insulating member 30 .

[0095] In some embodiments, see Figure 5 The secondary battery 100 includes a fourth insulating member 70, which is disposed on a side of the first electrode terminal 24 away from the first insulating member 30. When a fall or vibration occurs, it is helpful to reduce the possibility that the first electrode terminal 24 contacts the housing 10 (such as the bottom wall 111 of the housing 11) in a direction opposite to the second direction Y, thereby reducing the risk of short circuit.

[0096] In some embodiments, along the second direction Y, the projection of the fourth insulating member 70 at least partially overlaps with the projection of the second insulating portion 52. When a fall or vibration occurs, the cooperation between the fourth insulating member 70 and the second insulating portion 52 helps to further reduce the possibility that the first electrode terminal 24 contacts the housing 10 (such as the bottom wall 111 of the housing 11) in the direction opposite to the second direction Y, thereby further reducing the risk of short circuit.

[0097] In some embodiments, the fourth insulating member 70 is fixed to the outermost electrode piece of the electrode assembly 20 that is away from the first insulating member 30 .

[0098] In some embodiments, see Figure 3 The outermost pole piece of the electrode assembly 20 is a single-sided pole piece 25, which includes a third current collector 251 and a third active material layer 252, and the third active material layer 252 is only provided on one side of the single-sided pole piece 25 facing the inside of the electrode assembly 20. On the one hand, it is beneficial to improve the stability of the third insulating member 60 and / or the fourth insulating member 70 fixed to the single-sided pole piece 25; on the other hand, since the third active material layer 252 is not provided on the side of the single-sided pole piece 25 away from the inside of the electrode assembly 20, it is beneficial to further improve the energy density of the secondary battery 100.

[0099] In some embodiments, the secondary battery 100 includes a fixing member (not shown), which is disposed in the receiving cavity 101. The electrode assembly 20 is fixedly connected to the housing 10 through the fixing member. When a fall or vibration occurs, it is helpful to reduce the possibility of the electrode assembly 20 moving relative to the housing 10, thereby helping to reduce the possibility of the first electrode terminal 24 being offset.

[0100] In some embodiments, the fixing member is hot melt adhesive.

[0101] See also Figure 6 One embodiment of the present application provides an electric device 1000, comprising the secondary battery 100 as described above. The secondary battery 100 is conducive to reducing the risk of short circuit, which is conducive to improving the working stability of the electric device 1000. The energy density loss in the secondary battery 100 is low, which is conducive to improving the endurance of the electric device 1000. The electric device 1000 includes but is not limited to electronic devices such as mobile phones, tablet computers and laptops.

[0102] In addition, those skilled in the art should recognize that the above embodiments are only used to illustrate the present application, and are not intended to limit the present application. As long as they are within the essential scope of the present application, appropriate changes and modifications to the above embodiments are within the scope disclosed in the present application.

Claims

1. A secondary battery, characterized in that: include: A housing, wherein the housing is provided with a receiving cavity; An electrode assembly, the electrode assembly is arranged in the receiving cavity; the electrode assembly comprises a first pole piece, a second pole piece and a diaphragm, the first pole piece and the second pole piece have opposite polarities, and the diaphragm is arranged between the first pole piece and the second pole piece; the first pole piece is provided with a first electrode end, and the first electrode end is insulated and connected to the shell; Along a first direction, the first pole piece has a first edge, the second pole piece has a second edge, the second edge exceeds the first edge, and the first electrode terminal is connected to the first edge and exceeds the second edge; Along the first direction, the first electrode end and the portion of the electrode assembly located between the first edge and the second edge are the first portion, and the first electrode end and the portion of the electrode assembly located at the first edge away from the second edge are the second portion; along the second direction, the total thickness of the first portion is less than the total thickness of the second portion; A first insulating member, the first insulating member is arranged on a shell wall inside the shell; Along the second direction, the projection of the first insulating member covers the projection of the portion of the first electrode end that exceeds the second edge, and the projection of the first insulating member is separated from the projection of the first edge; the second direction is the thickness direction of the electrode assembly; The second direction is perpendicular to the first direction.

2. The secondary battery according to claim 1, characterized in that: The material of the first insulating member includes at least one of polypropylene, silicone rubber, fluororubber, polyvinyl chloride, polyethylene terephthalate, polycarbonate and nylon.

3. The secondary battery according to claim 2, characterized in that: Along the second direction, the thickness of the first insulating member is 5 μm to 200 μm.

4. The secondary battery according to claim 1, characterized in that: The material of the first insulating member includes at least one of ceramic coating, polytetrafluoroethylene, epoxy resin, fluorinated ethylene propylene and polyvinylidene fluoride.

5. The secondary battery according to claim 4, characterized in that: Along the second direction, the thickness of the first insulating member is 1 μm to 50 μm.

6. The secondary battery according to claim 1, characterized in that: The housing includes a first wall provided with the first insulating member, and along the second direction, the shortest distance between the first electrode end and the first wall is d, where d≤2 mm.

7. The secondary battery according to claim 1, characterized in that: The secondary battery includes a pole and a second insulating member, the pole is electrically connected to the first electrode end and passes through the outer shell, the second insulating member is disposed on the outer shell and is configured to insulate the pole from the outer shell; the second insulating member includes a first insulating portion and a second insulating portion, along the second direction, the first insulating portion is closer to the first insulating portion than the second insulating portion, and the projection of the first insulating member at least partially overlaps with the projection of the first insulating portion.

8. The secondary battery according to claim 1, characterized in that: The secondary battery includes a third insulating member disposed on a side of the first electrode terminal facing the first insulating member.

9. The secondary battery according to claim 1, characterized in that: The first electrode terminal includes a first electrode tab connected to the first edge, and in the first portion, the first electrode tab includes a metal layer and an insulating layer, and along the thickness direction of the metal layer, the insulating layer is relatively arranged on both sides of the metal layer; the first electrode sheet includes a first current collector and a first active material layer, and along the thickness direction of the first current collector, the first active material layer is relatively arranged on both sides of the first current collector; the metal layer is electrically connected to the first current collector and extends out of the first current collector along the first direction; Along the second direction, a projection of the insulating layer overlaps with a projection of the second pole piece.

10. The secondary battery according to claim 1, characterized in that: The first electrode terminal includes a first electrode tab connected to the first edge, and in the first portion, the first electrode tab includes a metal layer and an insulating layer, and along the thickness direction of the metal layer, the insulating layer is relatively arranged on both sides of the metal layer; the first electrode sheet includes a first current collector and a first active material layer, and along the thickness direction of the first current collector, the first active material layer is relatively arranged on both sides of the first current collector; the metal layer is electrically connected to the first current collector and extends out of the first current collector along the first direction; Along the second direction, the thickness of the insulating layer is smaller than the thickness of the first active material layer.

11. An electrical device, characterized in that: The invention comprises the secondary battery according to any one of claims 1 to 10.

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