Secondary batteries and electrical equipment

Abstract

This application discloses a secondary battery and an electrical device. The secondary battery includes a casing, an electrode assembly, a support member, and a seal. The casing includes a first housing and a second housing. The first housing includes a first wall and a first side wall, and the second housing includes a second wall and a second side wall. The first side wall and the second side wall are disposed opposite each other along the assembly direction of the first and second housings. The support member is disposed between the casing and the electrode assembly. Along a direction perpendicular to the assembly direction, the projection of the support member at least partially overlaps with the projections of both the first and second side walls. The smaller of the wall thicknesses of the first and second side walls is H0. The support member includes a first end and a second end disposed opposite each other, and the minimum distance between the first end and the first side wall is D. 11 The minimum distance between the second end and the second sidewall is D. 21 D 11 +D 21 <H0; and / or, the minimum distance between the first end and the second sidewall is D. 12 The minimum distance between the second end and the first sidewall is D. 22 D 12 +D 22 <H0. This helps reduce the risk of secondary battery leakage failure.

Description

Technical Field

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

[0002] Current secondary batteries include steel-cased batteries and pouch batteries. Generally, both steel-cased and pouch batteries include a casing and electrode assemblies housed within the casing. The casing of a steel-cased battery comprises a first housing and a second housing, which are connected in a sealed manner either by welding or by a sealing element. Summary of the Invention

[0003] For secondary batteries that are sealed and connected by sealing elements in the prior art, when the outer casing is subjected to external force (such as drop and compression), the first and second casings are prone to misalignment under the action of external force along the direction perpendicular to the assembly direction of the first and second casings. This causes the sealing element to be pulled and peeled off from the encapsulation interface of the first and second casings, resulting in leakage of the secondary battery.

[0004] In view of the above situation, it is necessary to provide a secondary battery that can help reduce the risk of leakage failure.

[0005] This application provides a secondary battery, including a casing, an electrode assembly, a support member, and a seal. The casing includes a first housing and a second housing, which together form a receiving cavity, and the electrode assembly is disposed within the receiving cavity. The first housing includes a first wall and a first sidewall connecting the periphery of the first wall. The second housing includes a second wall and a second sidewall connecting the periphery of the second wall. The first sidewall has a first surface facing the second sidewall on its side away from the first wall, and the second sidewall has a second surface facing the first sidewall on its side away from the second wall. The first surface and the second surface are arranged opposite each other along a first direction, which is the assembly direction of the first housing and the second housing. The support member is disposed between the casing and the electrode assembly along the receiving cavity from the inside out and perpendicular to the first direction. Along a second direction, the projection of the support member at least partially overlaps with the projections of the first sidewall and the second sidewall, and the second direction is perpendicular to the first direction. The seal member is disposed around the outer periphery of the first sidewall and the second sidewall and seals the casing. H0 is the smaller of the wall thickness of the first sidewall and the wall thickness of the second sidewall. Along the second direction, the support member includes a first end and a second end disposed opposite to each other. Viewed along the first direction, the minimum distance between the first end and the first sidewall along the second direction is D. 11 The minimum distance between the second end and the second sidewall along the second direction is D. 21 D 11 +D 21 <H0; and / or, when viewed along the first direction, the minimum distance between the first end and the second sidewall along the second direction is D. 12The minimum distance between the second end and the first sidewall along the second direction is D. 22 D 12 +D 22 <H0.

[0006] When the casing of the secondary battery is subjected to an external force along the second direction, the first casing and the second casing move relative to each other along the second direction under the action of the external force. This is achieved by setting a support member and limiting D. 11 +D 21 <H0 and / or D 12 +D 22 <H0> allows the first and second ends of the support member to abut against the first and second sidewalls respectively during the relative movement of the first and second housings along the second direction. This reduces the possibility of continuous relative movement between the first and second housings along the second direction, and helps reduce the possibility of peeling off the sealing interface between the seal and the first and second sidewalls along the second direction. Furthermore, the distance the first and second housings move relative to each other along the second direction is less than the thickness of the smaller of the first and second sidewalls, which helps reduce the possibility of misalignment between the first and second sidewalls along the second direction, resulting in gaps. Therefore, this helps reduce the risk of leakage failure in the secondary battery.

[0007] In one or more of the above embodiments, the first end abuts against one of the first sidewall and the second sidewall, and / or the second end abuts against the other of the first sidewall and the second sidewall. During the fabrication of the secondary battery, when the sealing member is pressurized and wrapped around the outer periphery of the first and second sidewalls, it is convenient to support the first and / or second sidewalls at both ends of the support member along the second direction, which helps to reduce the possibility of deformation of the first and / or second sidewalls.

[0008] In one or more of the above embodiments, along a third direction, the support member includes a third end and a fourth end disposed opposite to each other. Viewed along a first direction, the minimum distance between the third end and the first sidewall along the third direction is D. 31 The minimum distance between the fourth end and the second sidewall along the third direction is D. 41 D 31 +D 41 <H0. And / or, when viewed along the first direction, the minimum distance between the third end and the second sidewall along the third direction is D. 32 The minimum distance between the fourth end and the first sidewall along the third direction is D. 42 D 32 +D 42 <H0. Wherein, the third direction, the first direction, and the second direction are mutually perpendicular. When the casing of the secondary battery is subjected to an external force along the third direction, the first casing and the second casing move relative to each other along the third direction under the action of the external force. This is achieved by setting D... 31+D 41 <H0 and / or D 32 +D 42 <H0> allows the third and fourth ends of the support member to abut against the first and second sidewalls respectively during the relative movement of the first and second housings along a third direction. This reduces the possibility of continuous relative movement between the first and second housings along the third direction, and helps reduce the possibility of peeling off the sealing interface between the seal and the first and second sidewalls along the third direction. Furthermore, it allows the distance the first and second housings move relative to each other along the third direction to be less than the smaller wall thickness of the first and second sidewalls, which helps reduce the possibility of misalignment between the first and second sidewalls along the third direction, resulting in gaps. This further helps reduce the risk of leakage failure in the secondary battery.

[0009] In one or more of the above embodiments, the third end abuts against one of the first sidewall and the second sidewall, and / or the fourth end abuts against the other of the first sidewall and the second sidewall. During the fabrication of the secondary battery, when the seal is pressed around the outer periphery of the first and second sidewalls, it facilitates support of the first and / or second sidewalls at both ends along a third direction by the support member, which helps reduce the possibility of deformation of the first and / or second sidewalls.

[0010] In one or more of the above embodiments, the first housing and the second housing are insulated from each other. The electrode assembly has a negative electrode tab leading out the negative polarity and a positive electrode tab leading out the positive polarity. The negative electrode tab is connected to the first sidewall, and the positive electrode tab is connected to the second sidewall. Viewed along the first direction, the projection of the support member is a non-closed shape, and the projections of the negative and positive electrodes are separate from the projection of the support member. In this case, since the support member is located between the outer shell and the electrode assembly, and because the projection of the support member along the first direction is a non-closed shape, interference caused by the support member can be reduced when the negative and positive electrodes extend from the electrode assembly to the outer shell, which is beneficial to improving the ease of connection between the negative electrode tab and the first sidewall, and the positive electrode tab and the second sidewall. Furthermore, the support member is not too heavy, which helps to reduce the overall weight of the secondary battery.

[0011] In one or more of the above embodiments, the first housing and the second housing are insulated from each other, and the electrode assembly is provided with a negative electrode tab leading out the negative polarity and a positive electrode tab leading out the positive polarity. A support member encloses and forms a cavity; viewed along a first direction, the projection of the support member is a closed shape. The support member has an opening that extends through the surface of the support member near the cavity and the surface away from the cavity along the thickness direction of the support member. The negative electrode tab passes through the opening and connects to the first sidewall, and the positive electrode tab passes through the opening and connects to the second sidewall. The opening in the support member facilitates the connection between the negative electrode tab and the first sidewall, and between the positive electrode tab and the second sidewall. Furthermore, the fact that the projection of the support member along the first direction is a closed shape improves the structural strength of the support member. When the secondary battery casing is subjected to significant external forces, the possibility of deformation of the support member can be reduced, which helps to further reduce the risk of leakage failure of the secondary battery. In one or more of the above embodiments, along the first direction, the first surface and the second surface have a gap. When viewed from the cavity towards the outside of the secondary battery and perpendicular to the first direction, the opening and the gap at least partially overlap. The sealing element includes a filling portion disposed in the gap, the melting point of the filling portion being T, 95℃≤T≤130℃. By setting 95℃≤T≤130℃, before the secondary battery experiences thermal runaway, it is beneficial to reduce the possibility of premature melting of the filling portion, which helps maintain the insulation between the first and second shells and the sealing effect of the sealing element on the outer shell; when the secondary battery experiences thermal runaway, it is beneficial to allow the filling portion to melt in time to relieve pressure in the receiving cavity, which helps improve the safety of the secondary battery. Furthermore, the fact that the opening at least partially overlaps with the gap between the first and second surfaces can shorten the pressure relief path, which helps improve the convenience of pressure relief.

[0012] In one or more of the above embodiments, the shear modulus of the support is G, where G≥30GPa. When the first end and the second end of the support abut against the first sidewall and the second sidewall respectively, by setting G≥30GPa, the possibility of shear deformation of the support can be reduced, which is beneficial to further reduce the risk of leakage failure of the secondary battery.

[0013] In one or more of the above embodiments, the yield strength of the support member is σ, where σ ≥ 100 MPa. When the first end and the second end of the support member abut against the first sidewall and the second sidewall respectively, by setting σ ≥ 100 MPa, the possibility of bending deformation of the support member can be reduced, which is beneficial to further reduce the risk of leakage failure of the secondary battery.

[0014] In one or more of the above embodiments, the thickness of the support member is H1, where 0.03mm ≤ H1. By setting 0.03mm ≤ H1, the thickness of the support member is not too small, which helps to improve the structural strength of the support member.

[0015] In one or more of the above embodiments, 0.1mm ≤ H1 ≤ 0.8mm. Setting 0.1mm ≤ H1 helps to further improve the structural strength of the support. Setting H1 ≤ 0.8mm helps to further improve the energy density of the secondary battery.

[0016] In one or more of the above embodiments, along the first direction, the distance between the first sidewall and the second sidewall is D0, the size of the first sidewall is W1, the size of the second sidewall is W2, the larger of W1 and W2 is W0, the size of the support member is W3, and D0 + W0 < W3 ≤ W1 + W2 + D0. By setting D0 + W0 < W3 ≤ W1 + W2 + D0, when the support member can move along the first direction, the projection of the support member along the second direction can still at least partially overlap with the projections of the first sidewall and the second sidewall along the second direction, thereby helping to maintain the abutting function of the support member.

[0017] In one or more of the above embodiments, W1+W2<W3≤W1+W2+D0. By setting W1+W2<W3≤W1+W2+D0, when the distance between the first sidewall and the second sidewall changes along the first direction, it is convenient for the support member to abut against the first housing and the second housing respectively along the first direction, which helps to reduce the possibility of the first housing and the second housing coming into contact.

[0018] In one or more of the above embodiments, the support member is insulated from the first housing and the second housing. Along a first direction, a gap exists between the first surface and the second surface. The support member includes a protrusion disposed in the gap, which protrudes towards and connects to the seal. The protrusion helps to improve the stability of the insulation between the first housing and the second housing.

[0019] In one or more of the above embodiments, the material of the support member includes at least one selected from ceramics, glass, thermosetting resin, fluororubber, and mica. By including the above-mentioned materials in the material of the support member, it is beneficial to enable the support member to have better insulation performance.

[0020] In one or more of the above embodiments, the support member is made of a metallic material, and its surface is provided with an insulating coating. The insulating coating material includes at least one of ceramic, glass, thermosetting resin, fluororubber, and mica. By making the support member a metallic material and providing an insulating coating on its surface, the support member can achieve both insulation and high structural strength.

[0021] In one or more of the above embodiments, some of the support members are fixedly disposed on the first side wall, and some of the support members are fixedly disposed on the second side wall.

[0022] A second aspect of this application provides an electrical device including a secondary battery as described in the first aspect of this application. The secondary battery is less prone to leakage failure, which helps extend the service life of the electrical device. Attached Figure Description

[0023] Figure 1 This is an assembly diagram of a secondary battery provided in one embodiment of this application.

[0024] Figure 2 This is an exploded view of the secondary battery provided in the first embodiment of this application.

[0025] Figure 3 This is a schematic diagram of an electrode assembly and support provided in an embodiment of this application, disposed within a housing.

[0026] Figure 4 This is a schematic diagram showing that the outer walls of the first and second sidewalls are substantially flush with each other, according to an embodiment of this application.

[0027] Figure 5 This is a schematic diagram showing that the inner walls of the first and second sidewalls are substantially flush, according to an embodiment of this application.

[0028] Figure 6 This is a schematic diagram showing the first end and the second end protruding toward the first sidewall, respectively, according to an embodiment of this application.

[0029] Figure 7 This is a schematic diagram showing the dimensions of a support member along a first direction, according to an embodiment of this application.

[0030] Figure 8 This is an exploded view of a secondary battery provided in the second embodiment of this application.

[0031] Figure 9 An exploded view of a secondary battery provided in the third embodiment of this application.

[0032] Figure 10 This is a schematic diagram of an electrical device provided in an embodiment of this application.

[0033] Explanation of main component symbols 1000 Electrical equipment; 100 Secondary battery; 10 Outer casing; 101 Receiving cavity; 11 First casing; 111 First wall; 112 First side wall; 1121 First surface; 121 Second wall; 122 Second side wall; 1221 Second surface; 20 Electrode assembly; 201 Negative electrode tab; 202 Positive electrode tab; 21 Negative electrode plate; 22 Positive electrode plate; 23 Separator; 30 Support member; 31 First end; 32 Second end; 33 Third end; 34 Fourth end; 35 Opening; 36 Protrusion; 40 Sealing member; 401 Filler; 41 First adhesive layer; 42 Metal layer; 43 Second adhesive layer; 50 Fixing member; X, First direction; Y, Second direction; Z, Third direction. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0035] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or may also have a component that is centrally located. When a component is considered to be "set" on another component, it can be directly set on the other component or may also have a component that is centrally located.

[0036] Unless otherwise stated, the term "multiple" as used herein refers to two or more.

[0037] The terms “first”, “second”, etc., are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implying the quantity, specific order, or primary and secondary relationship of the indicated technical features.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] It should be understood that, considering actual machining tolerances, in the technical solution of this application, when two components are arranged parallel / perpendicularly, the included angle between the two components is allowed to have a tolerance within 10% of the included angle corresponding to the parallel / perpendicular arrangement. In the technical solution of this application, when two parameters are equal, a tolerance within 10% is allowed between the two parameters.

[0040] This application provides a secondary battery, including a casing, an electrode assembly, a support member, and a seal. The casing includes a first housing and a second housing, which together form a receiving cavity, and the electrode assembly is disposed within the receiving cavity. The first housing includes a first wall and a first sidewall connecting the periphery of the first wall. The second housing includes a second wall and a second sidewall connecting the periphery of the second wall. The side of the first sidewall away from the first wall has a first surface facing the second sidewall, and the side of the second sidewall away from the second wall has a second surface facing the first sidewall. The first surface and the second surface are arranged opposite each other along a first direction, which is the assembly direction of the first housing and the second housing. The support member is disposed between the casing and the electrode assembly along the receiving cavity from the inside out and perpendicular to the first direction. Along a second direction, the projection of the support member at least partially overlaps with the projections of the first sidewall and the second sidewall, and the second direction is perpendicular to the first direction. The seal member is disposed around the outer periphery of the first sidewall and the second sidewall and seals the casing. The smaller of the wall thickness of the first sidewall and the wall thickness of the second sidewall is H0. Along the second direction, the support member includes a first end and a second end arranged opposite each other. When viewed along the first direction, the distance between the first end and the first sidewall along the second direction is D. 11 The minimum distance between the second end and the second sidewall along the second direction is D. 21 D 11 +D 21 <H0; and / or, when viewed along the first direction, the minimum distance between the first end and the second sidewall along the second direction is D. 12 The distance between the second end and the first sidewall along the second direction is D. 22 D 12 +D 22 <H0.

[0041] In the secondary battery of this application, when the outer casing of the secondary battery is subjected to an external force along a second direction, the first casing and the second casing move relative to each other along the second direction under the action of the external force. This is achieved by providing a support member and limiting D. 11 +D 21 <H0 and / or D 12 +D 22 <H0> allows the first and second ends of the support member to abut against the first and second sidewalls respectively during the relative movement of the first and second housings along the second direction. This reduces the possibility of continuous relative movement between the first and second housings along the second direction, and helps reduce the possibility of peeling off the sealing interface between the seal and the first and second sidewalls along the second direction. Furthermore, the distance the first and second housings move relative to each other along the second direction is less than the thickness of the smaller of the first and second sidewalls, which helps reduce the possibility of misalignment between the first and second sidewalls along the second direction, resulting in gaps. Therefore, this helps reduce the risk of leakage failure in the secondary battery.

[0042] Some embodiments of this application will now be described with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0043] Please see Figures 1 to 3 This application provides a secondary battery 100, including a housing 10, an electrode assembly 20, a support 30, and a seal 40. The electrode assembly 20 and the support 30 are housed within the housing 10, and the seal 40 is disposed on the outer wall of the housing 10 and used to seal the housing 10. In some embodiments, when the secondary battery 100 experiences thermal runaway, at least a portion of the seal 40 can melt to facilitate pressure relief of the secondary battery 100.

[0044] Please refer to the following: Figure 2 and Figure 3 The outer casing 10 includes a first casing 11 and a second casing 12, which together form a receiving cavity 101 filled with electrolyte. The electrode assembly 20 and the support member 30 are disposed within the receiving cavity 101. The outer casing 10 includes, but is not limited to, a metal casing, and the materials of the first casing 11 and the second casing 12 may be the same or different; this application does not impose any limitations on this. The electrode assembly 20 includes a negative electrode 21, a positive electrode 22, and a separator 23. The negative electrode 21 and the positive electrode 22 are alternately arranged, and the separator 23 separates the negative electrode 21 from the positive electrode 22. The assembly direction of the first casing 11 and the second casing 12 is defined as the first direction X, and the thickness direction of the electrode assembly 20 is parallel to the first direction X.

[0045] In some embodiments, the first housing 11 is a steel housing, the second housing 12 is an aluminum housing, the negative electrode 21 is electrically connected to the first housing 11, and the positive electrode 22 is electrically connected to the second housing 12. In this case, the first housing 11 and the second housing 12 are insulated from each other. In some embodiments, the first housing 11 is a steel housing, the second housing 12 is an aluminum housing, the thickness of the first housing 11 is 10 μm to 200 μm, the thickness of the second housing 12 is 100 μm to 500 μm, and the thickness of the first housing 11 is less than the thickness of the second housing 12.

[0046] In some embodiments, the outer casing 10 is a metal casing, and the first casing 11 and the second casing 12 are insulated from each other with poles (not shown). The negative electrode 21 is electrically connected to the pole provided on the first casing 11, and the positive electrode 22 is electrically connected to the pole provided on the second casing 12. In this case, the first casing 11 and the second casing 12 are not limited to being insulated or conductive.

[0047] Please see Figure 2 or Figure 3The first housing 11 includes a first wall 111 and a first side wall 112, and the second housing 12 includes a second wall 121 and a second side wall 122. The first side wall 112 connects to the periphery of the first wall 111, and the second side wall 122 connects to the periphery of the second wall 121. The first side wall 112 may be inclined or perpendicular to the first wall 111, and the second side wall 122 may be inclined or perpendicular to the second wall 121. This application does not impose any limitations on this. Please refer to [link / reference]. Figure 3 Along the receiving cavity 101 from the inside out and in a direction perpendicular to the first direction X, the support member 30 is disposed between the housing 10 and the electrode assembly 20. Along the second direction Y, the projection of the support member 30 at least partially overlaps with the projections of the first sidewall 112 and the second sidewall 122, and the second direction Y is perpendicular to the first direction X. For example, when the projection of the housing 10 along the first direction X is rectangular, the second direction Y can be either the length direction or the width direction of the housing 10. The sealing member 40 is wrapped around the outer periphery of the first sidewall 112 and the second sidewall 122, sealing the housing 10. The side of the first sidewall 112 away from the first wall 111 has a first surface 1121 facing the second sidewall 122, and the side of the second sidewall 122 away from the second wall 121 has a second surface 1221 facing the first sidewall 112. Along the first direction X, the first surface 1121 and the second surface 1221 are arranged facing each other. In some embodiments, along the first direction X, the first surface 1121 and the second surface 1221 have a gap, and the seal 40 seals the gap.

[0048] In some embodiments, the electrode assembly 20 has a stacked structure, with negative electrode 21 and positive electrode 22 alternately stacked, wherein a separator 23 is disposed between the negative electrode 21 and the positive electrode 22. In some embodiments, the electrode assembly 20 has a wound structure, with negative electrode 21 and positive electrode 22 alternately wound, wherein a separator 23 is disposed between the negative electrode 21 and the positive electrode 22.

[0049] In some embodiments, the negative electrode 21 includes a negative current collector and a negative active material layer, the negative active material layer being disposed on two opposing sides of the negative current collector along its thickness direction. The positive electrode 22 includes a positive current collector and a positive active material layer, the positive active material layer being disposed on two opposing sides of the positive current collector along its thickness direction. In some embodiments, the material of the negative current collector includes at least one of copper, nickel, tantalum, and titanium, and the material of the positive current collector includes at least one of aluminum, nickel, tantalum, and titanium. In some embodiments, the material of the negative active material layer includes at least one of graphite, hard carbon, soft carbon, silicon, silicon-oxygen materials, and silicon-carbon materials. The material of the positive active material layer includes at least one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium manganese iron phosphate, or lithium manganese oxide.

[0050] In some embodiments, the diaphragm 23 is an insulating membrane material such as a polyethylene membrane, a polypropylene membrane, a polyester membrane, or a polyimide membrane.

[0051] In some embodiments, when the negative electrode 21 is the outermost electrode of the electrode assembly 20, the side of the negative current collector facing away from the interior of the electrode assembly 20 has an empty foil area, and the negative current collector is directly connected to the first wall 111 through the empty foil area. When the positive electrode 22 is the outermost electrode of the electrode assembly 20, the side of the positive current collector facing away from the interior of the electrode assembly 20 has an empty foil area, and the positive current collector is directly connected to the second wall 121 through the empty foil area. It should be understood that when the electrode assembly 20 is a stacked structure, the outermost electrode is the electrode closest to the first wall 111 or the second wall 121 among several electrodes of the electrode assembly 20 along the thickness direction of the electrode assembly 20. When the electrode assembly 20 is a wound structure, the outermost electrode is the flat area of ​​the outermost wound electrode located between the bending areas and close to the first wall 111 or the second wall 121.

[0052] Please see Figure 2 In some embodiments, the electrode assembly 20 is provided with a negative electrode tab 201 leading out the negative polarity and a positive electrode tab 202 leading out the positive polarity. The negative electrode tab 201 is connected to the first sidewall 112, and the positive electrode tab 202 is connected to the second sidewall 122. This facilitates the connection of the negative electrode tab 201 to the first housing 11 and the positive electrode tab 202 to the second housing 12, which improves the ease of manufacturing the secondary battery 100. When the first wall 111 and the second wall 121 are arranged opposite each other along the thickness direction of the secondary battery 100, the connection of the negative electrode tab 201 to the first sidewall 112 and the connection of the positive electrode tab 202 to the second sidewall 122 also helps to reduce the space occupied by the secondary battery 100 along the thickness direction. In some embodiments, multiple negative electrode tabs 201 are gathered to form a negative electrode tab bundle, and the negative electrode tab bundle is in direct contact with the first sidewall 112. Multiple positive electrode tabs 202 are gathered to form a positive electrode tab bundle, and the positive electrode tab bundle is in direct contact with the second sidewall 122.

[0053] Please see Figures 4 to 6 The smaller of the wall thickness of the first sidewall 112 and the wall thickness of the second sidewall 122 is H0. Along the second direction Y, the support member 30 includes a first end 31 and a second end 32 disposed opposite to each other. Viewed along the first direction X, the minimum distance between the first end 31 and the first sidewall 112 along the second direction Y is D. 11 The minimum distance between the second end 32 and the second sidewall 122 along the second direction Y is D. 21 D 11 +D 21 <H0. And / or, when viewed along the first direction X, the minimum distance between the first end 31 and the second sidewall 122 along the second direction Y is D. 12 The minimum distance between the second end 32 and the first sidewall 112 along the second direction Y is D. 22 D 12 +D22 <H0. When the outer casing 10 of the secondary battery 100 is subjected to an external force along the second direction Y, the first casing 11 and the second casing 12 move relative to each other along the second direction Y under the action of the external force, and the support member 30 is provided and the D is limited. 11 +D 21 <H0 and / or D 12 +D 22 <H0> This design allows the first end 31 and the second end 32 of the support member 30 to abut against the first sidewall 112 and the second sidewall 122 respectively during the relative movement of the first housing 11 and the second housing 12 along the second direction Y. This reduces the possibility of continuous relative movement of the first housing 11 and the second housing 12 along the second direction Y, and helps reduce the possibility of peeling of the sealing member 40 from the encapsulation interface of the first sidewall 112 and the second sidewall 122 along the second direction Y. Furthermore, this design ensures that the distance the first housing 11 and the second housing 12 move relative to each other along the second direction Y is less than the thickness of the smaller of the first sidewall 112 and the second sidewall 122, which helps reduce the possibility of misalignment between the first sidewall 112 and the second sidewall 122 along the second direction Y, thus reducing the risk of leakage failure of the secondary battery 100.

[0054] In some embodiments, the first end 31 abuts against one of the first sidewall 112 and the second sidewall 122, and / or the second end 32 abuts against the other of the first sidewall 112 and the second sidewall 122. During the fabrication of the secondary battery 100, when the sealing member 40 is pressurized and positioned around the outer periphery of the first sidewall 112 and the second sidewall 122, the first sidewall 112 and / or the second sidewall 122 can be easily supported by the support member 30 at both ends along the second direction Y, which helps to reduce the possibility of deformation of the first sidewall 112 and / or the second sidewall 122.

[0055] In some embodiments, please refer to Figure 4 Viewed along the first direction X, the outer walls of the first sidewall 112 and the second sidewall 122 are substantially flush. In some embodiments, please refer to... Figure 5 When viewed along the first direction X, the inner walls of the first sidewall 112 and the second sidewall 122 are basically flush.

[0056] In some embodiments, please refer to Figure 6 Viewed along the first direction X, the outer walls of the first sidewall 112 and the second sidewall 122 are basically flush. The portion of the first end 31 and the portion of the second end 32 protrude towards the sidewall 112 or the sidewall 122 with the smaller wall thickness. When H0 is small, this facilitates the movement of D... 11 +D 21 <H0 and / or D 12 +D22 <H0.

[0057] In some embodiments, please refer to Figure 7 Along the first direction X, the distance between the first sidewall 112 and the second sidewall 122 is D0, the dimension of the first sidewall 112 is W1, the dimension of the second sidewall 122 is W2, the larger of W1 and W2 is W0, and the dimension of the support member 30 is W3, where D0 + W0 < W3 ≤ W1 + W2 + D0. By setting D0 + W0 < W3 ≤ W1 + W2 + D0, when the support member 30 can move along the first direction X, the projection of the support member 30 along the second direction Y can still at least partially overlap with the projections of the first sidewall 112 and the second sidewall 122 along the second direction Y, thereby helping to maintain the abutting function of the support member 30. In some embodiments, when both the first surface 1121 and the second surface 1221 are perpendicular to the first direction X, the distance D0 between the first sidewall 112 and the second sidewall 122 along the first direction X can be the distance between the first surface 1121 and the second surface 1221.

[0058] In some embodiments, W1+W2<W3≤W1+W2+D0. By setting W1+W2<W3≤W1+W2+D0, when the distance between the first sidewall 112 and the second sidewall 122 changes along the first direction X, it is convenient for the support member 30 to abut against the first housing 11 and the second housing 12 along the first direction X, which helps to reduce the possibility of the first housing 11 and the second housing 12 coming into contact.

[0059] In some embodiments, please refer to Figure 8 or Figure 9 Along the third direction Z, the support member 30 includes a third end 33 and a fourth end 34 disposed opposite to each other. Viewed along the first direction X, the minimum distance between the third end 33 and the first sidewall 112 along the third direction Z is D. 31 The minimum distance between the fourth end 34 and the second sidewall 122 along the third direction Z is D. 41 D 31 +D 41 <H0. And / or, when viewed along the first direction X, the minimum distance between the third end 33 and the second sidewall 122 along the third direction Z is D. 32 The minimum distance between the fourth end 34 and the first sidewall 112 along the third direction Z is D. 42 D 32 +D 42 <H0. D 31 D 41 D 32 and D 42 The annotations can be referenced. Figures 4 to 6 D 11 D 21 D 12 and D22 The annotation is as follows. In this context, the third direction Z, the first direction X, and the second direction Y are mutually perpendicular. It should be understood that when the angle between two directions is within the range of 90°±10°, they are also considered perpendicular. When the outer casing 10 of the secondary battery 100 is subjected to an external force along the third direction Z, the first casing 11 and the second casing 12 move relative to each other along the third direction Z under the action of the external force. This is achieved by setting D... 31 +D 41 <H0 and / or D 32 +D 42 <H0> This design allows the third end 33 and the fourth end 34 of the support member 30 to abut against the first sidewall 112 and the second sidewall 122 respectively during the relative movement of the first housing 11 and the second housing 12 along the third direction Z. This reduces the possibility of continuous relative movement of the first housing 11 and the second housing 12 along the third direction Z, and helps reduce the possibility of peeling of the sealing member 40 from the encapsulation interface of the first sidewall 112 and the second sidewall 122 along the third direction Z. Furthermore, this design allows the distance the first housing 11 and the second housing 12 move relative to each other along the third direction Z to be less than the smaller wall thickness of the first sidewall 112 and the second sidewall 122, which helps reduce the possibility of misalignment between the first sidewall 112 and the second sidewall 122 along the third direction Z, resulting in gaps. Therefore, this design further reduces the risk of leakage failure of the secondary battery 100.

[0060] In some embodiments, the third end 33 abuts against one of the first sidewall 112 and the second sidewall 122, and / or the fourth end 34 abuts against the other of the first sidewall 112 and the second sidewall 122. During the fabrication of the secondary battery 100, when the sealing member 40 is pressurized and positioned around the outer periphery of the first sidewall 112 and the second sidewall 122, the first sidewall 112 and / or the second sidewall 122 can be easily supported by the support member 30 at both ends along the third direction Z, which helps to reduce the possibility of deformation of the first sidewall 112 and / or the second sidewall 122.

[0061] In some embodiments, when viewed along the first direction X, the outer walls of the first sidewall 112 and the second sidewall 122 are substantially flush, and portions of the third end 33 and the fourth end 34 protrude toward the sidewall 112 and the sidewall 122 with the smaller wall thickness, respectively. When H0 is small, this facilitates D... 31 +D 41 <H0 and / or D 32 +D 42 <H0.

[0062] In some embodiments, please refer to Figure 2 or Figure 8When viewed along the first direction X, the projection of the support member 30 is an unclosed figure, and the projections of the negative electrode tab 201 and the positive electrode tab 202 are separated from the projection of the support member 30. In this case, since the support member 30 is disposed between the casing 10 and the electrode assembly 20, the projection of the support member 30 along the first direction X is an unclosed figure. When the negative electrode tab 201 and the positive electrode tab 202 extend from the electrode assembly 20 to the casing 10, the interference caused by the support member 30 can be reduced, which is beneficial to improving the convenience of connecting the negative electrode tab 201 to the first side wall 112 and the positive electrode tab 202 to the second side wall 122. Moreover, the support member 30 will not be excessively heavy, which is beneficial to reducing the overall weight of the secondary battery 100. In some embodiments, when viewed along the first direction X, the projection of the support member 30 is substantially in a straight-line shape (see Figure 2 ), an L-shape (see Figure 8 ) or a C-shape.

[0063] In some embodiments, according to Figure 9 , the support member 30 encloses to form a cavity, and when viewed along the first direction X, the projection of the support member 30 is a closed figure. In some embodiments, the support member 30 is provided with an opening 35, and the opening 35 penetrates through a surface of the support member 30 close to the cavity and a surface of the support member 30 away from the cavity along the thickness direction of the support member 30. The negative electrode tab 201 passes through the opening 35 to be connected to the first side wall 112, and the positive electrode tab 202 passes through the opening 35 to be connected to the second side wall 122. The provision of the opening 35 on the support member 30 can facilitate the connection of the negative electrode tab 201 to the first side wall 112 and the positive electrode tab 202 to the second side wall 122. Moreover, since the projection of the support member 30 along the first direction X is a closed figure, the structural strength of the support member 30 can be improved. When the casing 10 of the secondary battery 100 is subjected to a large external force, the possibility of deformation of the support member 30 can be reduced, which is further beneficial to reducing the risk of leakage and failure of the secondary battery 100. In some embodiments, when viewed along the first direction X, the projection of the support member 30 is substantially in a square shape.

[0064] In some embodiments, the number of the openings 35 is multiple, and the negative electrode tab 201 and the positive electrode tab 202 are respectively connected to the first side wall 112 and the second side wall 122 through different openings 35, which is beneficial to reducing the risk of short circuit caused by contact between the negative electrode tab 201 and the positive electrode tab 202.

[0065] In some embodiments, when viewed along a direction that the cavity faces the outside of the secondary battery 100 and is perpendicular to the first direction X, the gap between the opening 35, the first surface 1121 and the second surface 1221 at least partially overlaps. In this case, when thermal runaway occurs in the secondary battery 100 and at least part of the seal member 40 melts for pressure relief, the at least partial overlap of the gap between the opening 35, the first surface 1121 and the second surface 1221 can shorten the pressure relief path, which is beneficial to improving the convenience of pressure relief.

[0066] In some embodiments, there are multiple openings 35, which are spaced apart circumferentially along the support member 30. When viewed from the cavity toward the outside of the secondary battery 100 and perpendicular to the first direction X, the gaps between the multiple openings 35 and the first surface 1121 and the second surface 1221 are at least partially overlapped, which is beneficial to further improve the convenience of pressure relief.

[0067] In some embodiments, the support member 30 is insulated from the first housing 11 and the second housing 12. (See also...) Figure 3 The support member 30 includes a protrusion 36 disposed in the gap between the first surface 1121 and the second surface 1221. The protrusion 36 protrudes in a direction toward the seal 40 and connects to the seal 40. The protrusion 36 helps to improve the stability of the insulation arrangement between the first housing 11 and the second housing 12. In some embodiments, the support member 30 is an insulating component, and the support member 30 includes an insulating material.

[0068] In some embodiments, the material of the support member 30 includes at least one selected from ceramics, glass, thermosetting resins, fluororubber, and mica. By including the above-mentioned materials in the material of the support member 30, it is advantageous to make the support member 30 have better insulation performance.

[0069] In some embodiments, the support member 30 is made of a metallic material, and its surface is provided with an insulating coating (not shown). The insulating coating material includes at least one of ceramic, glass, thermosetting resin, fluororubber, and mica. By making the support member 30 a metallic material and providing an insulating coating on its surface, it is advantageous for the support member 30 to have both insulating properties and high structural strength.

[0070] In some embodiments, please refer to Figure 3 Part of the support member 30 is fixedly disposed on the first sidewall 112, and part of the support member 30 is fixedly disposed on the second sidewall 122. This facilitates the first end 31 and the second end 32 of the support member 30 to abut against the first sidewall 112 and the second sidewall 122, respectively. In some embodiments, the third end 33 and the fourth end 34 of the support member 30 are also fixedly disposed on the first sidewall 112 and the second sidewall 122, respectively.

[0071] In some embodiments, please refer to Figure 3The thickness of the support member 30 is H1, where 0.03 mm ≤ H1. For example, H1 can be 0.03 mm, 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 1.5 mm, or any value between the listed endpoints. By setting H1 to 0.03 mm ≤ H1, the thickness of the support member 30 is not too small, which helps to improve the structural strength of the support member 30. It should be understood that since the support member 30 is disposed between the housing 10 and the electrode assembly 20 along the receiving cavity 101 from the inside out and perpendicular to the first direction X, the thickness of the support member 30 should not be too large, so that the required distance between the housing 10 and the electrode assembly 20 is not too large, which helps to improve the energy density of the secondary battery 100.

[0072] In some embodiments, 0.1mm ≤ H1 ≤ 0.8mm. Setting H1 to 0.1mm ≤ H1 helps to further improve the structural strength of the support member 30. Setting H1 ≤ 0.8mm helps to further improve the energy density of the secondary battery 100.

[0073] In some embodiments, the shear modulus of the support member 30 is G, where G ≥ 30 GPa. When the first end 31 and the second end 32 of the support member 30 abut against the first sidewall 112 and the second sidewall 122 respectively, setting G ≥ 30 GPa can reduce the possibility of shear deformation of the support member 30, which is beneficial to further reduce the risk of leakage failure of the secondary battery 100. In some embodiments, when the third end 33 and the fourth end 34 of the support member 30 abut against the first sidewall 112 and the second sidewall 122 respectively, setting G ≥ 30 GPa can reduce the possibility of shear deformation of the support member 30, which is beneficial to further reduce the risk of leakage failure of the secondary battery 100.

[0074] In some embodiments, the yield strength of the support member 30 is σ, where σ ≥ 100 MPa. When the first end 31 and the second end 32 of the support member 30 abut against the first sidewall 112 and the second sidewall 122 respectively, setting σ ≥ 100 MPa reduces the possibility of bending deformation of the support member 30, which helps to further reduce the risk of leakage failure of the secondary battery 100. In some embodiments, when the third end 33 and the fourth end 34 of the support member 30 abut against the first sidewall 112 and the second sidewall 122 respectively, setting σ ≥ 100 MPa reduces the possibility of bending deformation of the support member 30, which helps to further reduce the risk of leakage failure of the secondary battery 100.

[0075] In some embodiments, please refer to Figure 3The seal 40 includes a filler portion 401 disposed in the gap between the first surface 1121 and the second surface 1221. The filler portion 401 can be formed directly by melting a portion of the seal 40 into the gap between the first surface 1121 and the second surface 1221 and then cooling it. The filler portion 401 helps to improve the stability of the insulation between the first housing 11 and the second housing 12. In some embodiments, the filler portion 401 includes an insulating material.

[0076] In some embodiments, please refer to Figure 3 The protrusion 36 is connected to the filling part 401, which helps to further improve the stability of the insulation arrangement between the first housing 11 and the second housing 12.

[0077] In some embodiments, the melting point of the filling portion 401 is T, where 95°C ≤ T ≤ 130°C. For example, T can be 95°C, 100°C, 110°C, 130°C, or any value between the listed endpoints. By setting 95°C ≤ T ≤ 130°C, before the secondary battery 100 experiences thermal runaway, it is beneficial to reduce the possibility of the filling portion 401 melting prematurely, which helps maintain the insulation between the first housing 11 and the second housing 12, as well as the sealing effect of the sealant 40 on the outer casing 10. When the secondary battery 100 experiences thermal runaway, it is beneficial for the filling portion 401 to melt in time to relieve pressure in the receiving cavity 101, thereby improving the safety of the secondary battery 100.

[0078] Please see Figure 3 In some embodiments, the seal 40 includes a first adhesive layer 41, which is adhered to the outer periphery of the first sidewall 112 and the second sidewall 122, thereby improving the stability of the bond between the seal 40 and the housing 10. In some embodiments, the first adhesive layer 41 can melt or de-adhere upon heating, forming part of a pressure relief channel communicating with the receiving cavity 101. When the secondary battery 100 experiences thermal runaway, the melting or de-adhesion of the first adhesive layer 41 can promptly relieve pressure in the receiving cavity 101, thereby improving the safety of the secondary battery 100.

[0079] In some embodiments, the filler portion 401 is integrally formed with the first adhesive layer 41. The filler portion 401 can be formed directly by melting a portion of the first adhesive layer 41 and then cooling it into the gap between the first surface 1121 and the second surface 1221. This simplifies the assembly process of the secondary battery 100 and streamlines the manufacturing process. Furthermore, the integral formation of the filler portion 401 with the first adhesive layer 41 allows for a close fit between the first surface 1121 and the second surface 1221, improving the sealing performance of the sealant 40 on the first housing 11 and the second housing 12. In other embodiments, the filler portion 401 and the first adhesive layer 41 are separate components.

[0080] In some embodiments, the melting point of the first adhesive layer 41 is between 95°C and 130°C. For example, the melting point of the first adhesive layer 41 is 95°C, 100°C, 110°C, 130°C, or any value between the listed endpoints. By setting the melting point of the first adhesive layer 41 to between 95°C and 130°C, the possibility of the first adhesive layer 41 melting or losing adhesion before the secondary battery 100 experiences thermal runaway can be reduced, which is beneficial for maintaining the sealing effect of the sealant 40 on the outer casing 10. Furthermore, it can ensure that the first adhesive layer 41 melts or loses adhesion in a timely manner when the secondary battery 100 experiences thermal runaway, thereby relieving pressure in the receiving cavity 101 and improving the safety of the secondary battery 100. It should be understood that when the filling part 401 is integrally formed with the first adhesive layer 41, and the filling part 401 is formed directly by melting a portion of the first adhesive layer 41 and entering the gap between the first surface 1121 and the second surface 1221 and then cooling, the melting point of the filling part 401 is substantially the same as the melting point of the first adhesive layer 41.

[0081] In some embodiments, the material of the first adhesive layer 41 comprises an electrolyte-resistant polymer, wherein the polymer includes at least one selected from polyolefins, fluororubber, and polyurethane. The polyolefin may include polypropylene and polyethylene, etc. This enables the first adhesive layer 41 to have high resistance to electrolyte corrosion. In some embodiments, the first adhesive layer 41 comprises a single layer or multiple layers of polymer.

[0082] In some embodiments, please refer to Figure 3 The sealing element 40 includes a metal layer 42, which is disposed on the side of the first adhesive layer 41 away from the outer shell 10. The water resistance of the metal layer 42 is better than that of the first adhesive layer 41, which is beneficial to improving the sealing performance of the sealing element 40 to the first shell 11 and the second shell 12.

[0083] In some embodiments, the material of the metal layer 42 includes at least one selected from steel, aluminum, nickel, silver, copper, and alloys thereof. In some embodiments, the metal layer 42 is a single-layer or multi-layer structure. For example, a multi-layer structure is a steel layer plus an aluminum layer or a nickel layer plus a copper layer, etc.

[0084] In some embodiments, please refer to Figure 3 The seal 40 includes a second adhesive layer 43, which is disposed on the side of the metal layer 42 opposite to the first adhesive layer 41. The second adhesive layer 43 can protect the metal layer 42, which helps to reduce the risk of failure of the metal layer 42.

[0085] In some embodiments, the melting point of the second adhesive layer 43 is greater than that of the first adhesive layer 41. In some embodiments, the melting point difference between the second adhesive layer 43 and the first adhesive layer 41 is greater than 10°C.

[0086] In some embodiments, the melting point of the second adhesive layer 43 is between 140°C and 500°C. For example, the melting point of the second adhesive layer 43 is 140°C, 160°C, 200°C, 250°C, 300°C, 500°C, or any value between the listed endpoints.

[0087] In some embodiments, the material of the second adhesive layer 43 includes an electrolyte-resistant polymer, which includes at least one selected from polyolefins, fluoropolymers, polyetheretherketones, fluororubber, and polyurethanes. Polyolefins may include polypropylene and polyethylene, and fluoropolymers may be such as polytetrafluoroethylene. This allows the second adhesive layer 43 to have high resistance to electrolyte corrosion. In some embodiments, the second adhesive layer 43 comprises a single layer or multiple layers of polymer.

[0088] It should be understood that when the sealing element 40 simultaneously includes a first adhesive layer 41, a metal layer 42, and a second adhesive layer 43, the first adhesive layer 41 and the second adhesive layer 43 are respectively disposed on both sides of the metal layer 42 along the thickness direction of the metal layer 42. In some embodiments, the first adhesive layer 41 is fixed to the metal layer 42, and the second adhesive layer 43 is fixed to the metal layer 42 by adhesive bonding, so that the first adhesive layer 41, the metal layer 42, and the second adhesive layer 43 are combined into a whole. In some embodiments, the first adhesive layer 41 is fixed to the metal layer 42, and the second adhesive layer 43 is fixed to the metal layer 42 by hot pressing, so that the first adhesive layer 41, the metal layer 42, and the second adhesive layer 43 are combined into a whole. During the long-term use of the secondary battery 100, it is beneficial to maintain the sealing performance of the sealing element 40 to the first housing 11 and the second housing 12.

[0089] In some embodiments, along the thickness direction of the seal 40, the thickness of the first adhesive layer 41 is d1, the thickness of the metal layer 42 is d2, and the thickness of the second adhesive layer 43 is d3, where 7μm≤d1≤500μm, 7μm≤d2≤250μm, and 6μm≤d3≤500μm. For example, d1 is any value between 7μm, 10μm, 20μm, 50μm, 100μm, 200μm, 500μm, or any of the listed endpoint values; d2 is any value between 7μm, 10μm, 20μm, 50μm, 100μm, 150μm, 250μm, or any of the listed endpoint values; and d3 is any value between 6μm, 8μm, 20μm, 50μm, 100μm, 200μm, 500μm, or any of the listed endpoint values. By setting 7μm≤d1, 7μm≤d2, and 6μm≤d3, the first adhesive layer 41, metal layer 42, and second adhesive layer 43 are not too thin, which helps reduce the risk of the first adhesive layer 41 being corroded and failing by the electrolyte. It also helps reduce the risk of the second adhesive layer 43 breaking after the secondary battery 100 is dropped, leading to the failure of the metal layer 42 or its corrosion failure. By setting d1≤500μm, d2≤250μm, and d3≤500μm, the first adhesive layer 41, metal layer 42, and second adhesive layer 43 are not too thick, which helps improve the energy density of the secondary battery 100.

[0090] In some embodiments, 10μm≤d1≤200μm, 10μm≤d2≤150μm, and 8μm≤d3≤200μm. By setting 10μm≤d1, 10μm≤d2, and 8μm≤d3, the first adhesive layer 41, the metal layer 42, and the second adhesive layer 43 can be made thicker. This helps to further reduce the risk of the first adhesive layer 41 being corroded and failed by the electrolyte, and further reduces the risk of the second adhesive layer 43 breaking after the secondary battery 100 is dropped, leading to the failure of the metal layer 42 or its corrosion failure. By setting d1≤200μm, d2≤150μm, and d3≤200μm, the energy density of the secondary battery 100 can be further improved while ensuring that the thickness of the first adhesive layer 41 is basically sufficient to prevent corrosion failure by the electrolyte, the thickness of the second adhesive layer 43 is sufficient for most drop scenarios, and the thickness of the metal layer 42 is basically sufficient to prevent failure due to breakage or corrosion.

[0091] In some embodiments, the thickness of the first adhesive layer 41 may be uniform or non-uniform. In some embodiments, the thickness of the metal layer 42 may be uniform or non-uniform. In some embodiments, the thickness of the second adhesive layer 43 may be uniform or non-uniform. In some embodiments, the thickness of the seal 40 may be uniform or non-uniform, and the thickness of the seal 40 is equal to the sum of the thicknesses of the first adhesive layer 41, the metal layer 42, and the second adhesive layer 43.

[0092] In some embodiments, please refer to Figure 3 The secondary battery 100 also includes a retainer 50, which adheres to the outer casing 10 and the electrode assembly 20. This helps reduce the risk of the electrode assembly 20 shifting within the receiving cavity 101, causing the first casing 11 and / or the second casing 12 to detach from the seal 40. In some embodiments, the retainer 50 is disposed between the outer casing 10 and the electrode assembly 20 along a first direction X. In some embodiments, the retainer 50 is a hot melt adhesive.

[0093] Please see Figure 10 One embodiment of this application provides an electrical device 1000, including the secondary battery 100 as described above. The secondary battery 100 is less prone to leakage failure, which helps to extend the service life of the electrical device 1000. The electrical device 1000 includes, but is not limited to, electronic devices such as e-book players, mobile phones, fax machines, copiers, printers, headphones, video recorders, LCD TVs, recorders, radios, cameras, tablet computers, and laptop computers.

[0094] Furthermore, those skilled in the art should recognize that the above embodiments are merely illustrative of this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the substantive scope of this application fall within the scope of this application.

Claims

1. A secondary battery, characterized in that, include: The housing includes a first housing and a second housing, which together form a receiving cavity. The first housing includes a first wall and a first sidewall connecting the periphery of the first wall. The second housing includes a second wall and a second sidewall connecting the periphery of the second wall. The first sidewall has a first surface facing the second sidewall on its side away from the first wall, and the second sidewall has a second surface facing the first sidewall on its side away from the second wall. The first surface and the second surface are disposed opposite each other along a first direction, which is the assembly direction of the first housing and the second housing. The smaller of the wall thickness of the first sidewall and the wall thickness of the second sidewall is H0. The electrode assembly is disposed within the receiving cavity; A support member is disposed between the housing and the electrode assembly along the direction from the inside out of the receiving cavity and perpendicular to the first direction; along the second direction, the projection of the support member at least partially overlaps with the projections of the first sidewall and the second sidewall, and the second direction is perpendicular to the first direction. A sealing element is disposed around the outer periphery of the first sidewall and the second sidewall, and seals the outer casing; Wherein, along the second direction, the support member includes a first end and a second end disposed opposite to each other; viewed along the first direction, the minimum distance between the first end and the first sidewall along the second direction is D. 11 The minimum distance between the second end and the second sidewall along the second direction is D. 21 D 11 +D 21 <H0; and / or, when viewed along the first direction, the minimum distance between the first end and the second sidewall along the second direction is D. 12 The minimum distance between the second end and the first sidewall along the second direction is D. 22 D 12 +D 22 <H0.

2. The secondary battery according to claim 1, characterized in that, The first end abuts against one of the first sidewall and the second sidewall, and / or the second end abuts against the other of the first sidewall and the second sidewall.

3. The secondary battery according to claim 1 or 2, characterized in that, Along the third direction, the support member includes a third end and a fourth end disposed opposite to each other; viewed along the first direction, the minimum distance between the third end and the first sidewall along the third direction is D. 31 The minimum distance between the fourth end and the second sidewall along the third direction is D. 41 D 31 +D 41 <H0; and / or, when viewed along the first direction, the minimum distance between the third end and the second sidewall along the third direction is D. 32 The minimum distance between the fourth end and the first sidewall along the third direction is D. 42 D 32 +D 42 <H0; Wherein, the third direction, the first direction, and the second direction are all perpendicular to each other.

4. The secondary battery according to claim 3, characterized in that, The third end abuts against one of the first sidewall and the second sidewall, and / or the fourth end abuts against the other of the first sidewall and the second sidewall.

5. The secondary battery according to claim 1, characterized in that, The first housing and the second housing are insulated from each other. The electrode assembly is provided with a negative electrode tab leading out the negative polarity and a positive electrode tab leading out the positive polarity. The negative electrode tab is connected to the first sidewall, and the positive electrode tab is connected to the second sidewall. When viewed along the first direction, the projection of the support member is a non-closed shape, and the projections of the negative electrode tab and the positive electrode tab are separate from the projection of the support member.

6. The secondary battery according to claim 1, characterized in that, The first housing and the second housing are insulated from each other. The electrode assembly is provided with a negative electrode tab leading out the negative polarity and a positive electrode tab leading out the positive polarity. The support member encloses and forms a cavity. When viewed along the first direction, the projection of the support member is a closed shape. The support member is provided with an opening. Along the thickness direction of the support member, the opening penetrates the surface of the support member near the cavity and the surface away from the cavity. The negative electrode tab passes through the opening and connects to the first sidewall, and the positive electrode tab passes through the opening and connects to the second sidewall.

7. The secondary battery according to claim 6, characterized in that, Along the first direction, the first surface and the second surface have a gap. When viewed from the cavity toward the outside of the secondary battery and perpendicular to the first direction, the opening and the gap at least partially overlap. The seal includes a filling portion disposed in the gap, and the melting point of the filling portion is T, 95℃≤T≤130℃.

8. The secondary battery according to claim 1, characterized in that, The shear modulus of the support is G, where G≥30GPa.

9. The secondary battery according to claim 1, characterized in that, The yield strength of the support is σ, where σ ≥ 100 MPa.

10. The secondary battery according to claim 1, characterized in that, The thickness of the support member is H1, and 0.03mm ≤ H1.

11. The secondary battery according to claim 10, characterized in that, 0.1mm≤H1≤0.8mm.

12. The secondary battery according to claim 1, characterized in that, Along the first direction, the distance between the first sidewall and the second sidewall is D0, the size of the first sidewall is W1, the size of the second sidewall is W2, the larger of W1 and W2 is W0, the size of the support member is W3, and D0+W0<W3≤W1+W2+D0.

13. The secondary battery according to claim 12, characterized in that, W1+W2<W3≤W1+W2+D0.

14. The secondary battery according to claim 1, characterized in that, The support member is insulated from the first housing and the second housing. Along the first direction, the first surface and the second surface have a gap. The support member includes a protrusion disposed in the gap. The protrusion protrudes toward the seal and connects to the seal.

15. The secondary battery according to claim 1, characterized in that, The material of the support includes at least one of ceramics, glass, thermosetting resin, fluororubber, and mica.

16. The secondary battery according to claim 1, characterized in that, The support member is made of metal, and the surface of the support member is provided with an insulating coating. The insulating coating is made of at least one of ceramic, glass, thermosetting resin, fluororubber, and mica.

17. The secondary battery according to claim 1, characterized in that, Some of the support members are fixedly disposed on the first side wall, and some of the support members are fixedly disposed on the second side wall.

18. An electrical appliance, characterized in that, Includes the secondary battery as described in any one of claims 1 to 17.

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