Secondary battery and electric device
By using a combined design of insulating support and seals in secondary batteries, the problem of short-circuiting of the housing contact at high temperatures is solved, and higher safety and energy density are achieved.
Patent Information
- Application Number
- CN202510779559.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-11
- Publication Date
- 2025-08-12
AI Technical Summary
Existing secondary batteries are prone to short-circuiting the shell contact due to melting of the glue layer at high temperatures, which poses safety risks.
The combination of insulating support and seal is designed with a higher melting point than the seal, which together fills the shell gap, ensuring the shell insulation and maintains isolation at high temperatures.
It effectively reduces the risk of short circuit caused by housing contact of secondary batteries and improves the safety and energy density of the battery.
Smart Images
Figure CN120473625A_ABST
Abstract
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] Current secondary batteries include steel-cased batteries and soft-pack batteries. Generally speaking, both steel-cased batteries and soft-pack batteries include an outer shell and an electrode assembly disposed within the outer shell. The outer shell of a steel-cased battery includes a first shell and a second shell, which are sealed and connected by welding. Summary of the Invention
[0003] Regarding the secondary batteries in the prior art, the inventors have found that when the first shell and the second shell are electrically connected to different polarities of the electrode assembly, respectively, the first shell and the second shell generally need to be separated by a glue layer to achieve insulation. However, when the internal temperature of the secondary battery rises, the glue layer is prone to melting, causing the first shell and the second shell to come into contact, thereby leading to the risk of short circuit in the secondary battery.
[0004] In view of the above situation, it is necessary to provide a secondary battery that is conducive to reducing the risk of short circuit.
[0005] In a first aspect, the present application provides a secondary battery comprising a housing, an electrode assembly, a sealing member, and an insulating support member. The housing comprises a first shell and a second shell, the first shell and the second shell being insulated and forming a receiving cavity together, the receiving cavity being filled with electrolyte. The first shell comprises a first wall and a first sidewall connected to the periphery of the first wall, the second shell comprises a second wall and a second sidewall connected to the periphery of the second wall, the first sidewall being provided with a first face, the first face facing the second sidewall along the extension direction of the first sidewall, the second sidewall being provided with a second face, the second face facing the first sidewall along the extension direction of the second sidewall, the first face and the second face being arranged opposite each other and having a gap therebetween. The electrode assembly is disposed within the receiving cavity, the positive electrode of the electrode assembly being electrically connected to the first shell, and the negative electrode of the electrode assembly being electrically connected to the second shell. The sealing member is disposed around the periphery of the first and second sidewalls and seals the gap, the sealing member comprising a filling portion disposed in the gap. The insulating support member is at least partially located in the gap, the filling portion and the insulating support member jointly filling the gap. When viewed from the inside to the outside of the receiving cavity and perpendicular to the assembly direction of the first shell and the second shell, at least part of the filling portion does not overlap with the insulating support member, and the melting point of the insulating support member is greater than that of the filling portion.
[0006] By positioning the filling portion of the sealing member within the gap and at least partially positioning the insulating support member within the gap, the filling portion and the insulating support member can jointly separate the first and second shells, thereby facilitating insulation between the first and second shells. By setting the melting point of the insulating support member higher than that of the filling portion, even if the filling portion melts due to a rise in the internal temperature of the secondary battery, the insulating support member can still separate the first and second shells, thereby mitigating the risk of a short circuit in the secondary battery.
[0007] In one or more of the above embodiments, the secondary battery includes a plurality of insulating support members. When viewed along the assembly direction of the first shell and the second shell, the plurality of insulating support members and the line connecting two adjacent ends of the plurality of insulating support members along the circumferential direction of the seal enclose a support region. The area of the support region is S1, and the projected area of the shell is S2, where 0.3≤S1 / S2≤1. By setting 0.3≤S1 / S2≤1, the area of the support region is not too small. If the filling portion melts due to an increase in the internal temperature of the secondary battery, the possibility of the first shell or the second shell tilting toward the position where the filling portion was before melting, resulting in contact between the first shell and the second shell, can be reduced, which helps to further reduce the risk of a short circuit in the secondary battery.
[0008] In one or more of the above embodiments, the secondary battery includes a plurality of insulating support members. When viewed along the assembly direction of the first and second shells, the plurality of insulating support members enclose a support region that covers the center of gravity of the first and second shells. By ensuring that the support region covers the center of gravity of the first and second shells, if the filling portion melts due to an increase in the internal temperature of the secondary battery, the possibility of the first or second shell tilting toward the position where the filling portion was before melting, which could lead to contact between the first and second shells, can be reduced, thereby further reducing the risk of a short circuit in the secondary battery.
[0009] In one or more of the above embodiments, the insulating support member and the filling portion are interconnected along the circumference of the gap to jointly fill the gap. The insulating support member and the filling portion can independently support the first shell and the second shell. If the filling portion melts due to an increase in the internal temperature of the secondary battery, it is beneficial to maintain the stability of the first shell and the second shell.
[0010] In one or more of the above embodiments, the insulating support member is made of at least one of ceramic, glass, thermosetting resin, fluororubber, and mica. By making the insulating support member comprise the above materials, the insulating support member can achieve better insulation and support effects.
[0011] In one or more of the above embodiments, the thickness D of the portion of the insulating support member disposed in the gap along the assembly direction of the first shell and the second shell is 7μm≤D≤5000μm. By setting 7μm≤D≤5000μm, the thickness of the insulating support member is neither too thin nor too thick, thereby ensuring that the insulating support member has a certain insulation effect while also facilitating an increase in the energy density of the secondary battery.
[0012] In one or more of the above embodiments, 40 μm ≤ D ≤ 3000 μm. By setting 40 μm ≤ D ≤ 3000 μm, the thickness of the insulating support member is more appropriate, which can not only provide a better insulation effect for the insulating support member, but also further improve the energy density of the secondary battery. This also helps to reduce the possibility of the insulating support member being worn and failing during the long-term use of the secondary battery.
[0013] In one or more of the above embodiments, the insulating support member and the filling portion are stacked along the assembly direction of the first shell and the second shell to fill the gap together, which is beneficial to reducing the possibility of short circuit between the first shell and the second shell due to burr contact.
[0014] In one or more of the above embodiments, the insulating support member is an insulating coating, and the material of the insulating coating includes at least one of an inorganic non-metallic material, a fluoropolymer, and a thermosetting resin. The insulating support member can be formed by applying the insulating coating, which can reduce burrs during coating, thereby reducing the possibility of short circuits between the first and second shells caused by contact between burrs. Furthermore, by making the insulating support member include the above materials, the insulating support member can achieve better insulation and support effects.
[0015] In one or more of the above embodiments, the thickness D of the portion of the insulating support member disposed in the gap along the assembly direction of the first shell and the second shell is 0.1 μm ≤ D ≤ 500 μm. By setting 0.1 μm ≤ D ≤ 500 μm, the thickness of the insulating support member is neither too thin nor too thick, thereby ensuring that the insulating support member has a certain insulation effect while also facilitating an increase in the energy density of the secondary battery.
[0016] In one or more of the above embodiments, 1 μm ≤ D ≤ 200 μm. By setting 1 μm ≤ D ≤ 200 μm, the thickness of the insulating support member is more appropriate, which can not only provide a better insulation effect for the insulating support member, but also further improve the energy density of the secondary battery. This also helps reduce the possibility of the insulating support member being worn and failing during long-term use of the secondary battery.
[0017] In one or more of the above embodiments, the Young's modulus of the insulating support member is greater than or equal to 500 MPa, which is beneficial for the insulating support member to have a better supporting effect.
[0018] In one or more of the above embodiments, the melting point of the filling part is T1, the melting point of the insulating support is T2, 95℃≤T1≤130℃, and T2>150℃. By setting 95℃≤T1≤130℃, the possibility of premature melting of the filling part before thermal runaway of the secondary battery can be reduced, which is beneficial to maintaining the sealing effect of the seal on the outer shell. In addition, it can ensure that the filling part melts in time to relieve the pressure of the receiving cavity when thermal runaway of the secondary battery occurs, which is beneficial to improving the safety of the secondary battery. By setting T2>150℃, it is beneficial to reduce the risk of melting of the insulating support when the filling part melts.
[0019] In one or more of the above embodiments, the insulating support member is disposed on the first side wall and the second side wall, and the insulating support member disposed on the first side wall and the insulating support member disposed on the second side wall are disposed separately. This allows the insulating support member to be adapted to the first side wall and the second side wall, respectively, and helps reduce the possibility of deformation of the insulating support member under stress when there is an assembly error between the first shell and the second shell.
[0020] In one or more of the above embodiments, the insulating support member includes a support portion provided in the gap and a limiting portion connected to the support portion. The insulating support member is provided on the first side wall, and along the wall thickness direction of the first side wall, the projection of the limiting portion partially overlaps with the projection of the first side wall, and / or the insulating support member is provided on the second side wall, and the projection of the limiting portion at least partially overlaps with the projection of the second side wall. By providing the limiting portion, the supporting effect of the insulating support member can be improved. If the filling portion melts due to the increase in the internal temperature of the secondary battery, it is beneficial to maintain the stability of the first shell and the second shell.
[0021] The second aspect of the present application provides an electrical device comprising the secondary battery of the first aspect of the present application. The secondary battery is not prone to short circuit, which is beneficial for extending the service life of the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 A top view of a secondary battery provided in accordance with an embodiment of the present application.
[0023] Figure 2 This is a front view of a secondary battery provided in one embodiment of the present application.
[0024] Figure 3 An exploded view of a secondary battery provided in one embodiment of the present application.
[0025] Figure 4 For the first embodiment of this application Figure 1 Cross-section along the median line AA.
[0026] Figure 5 The second embodiment of this application is Figure 1 Cross-section along the median line AA.
[0027] Figure 6 The third embodiment of this application is Figure 1 Cross-section along the median line AA.
[0028] Figure 7 The fourth embodiment of this application is Figure 1 Cross-section along the median line AA.
[0029] Figure 8 The fifth embodiment of this application is Figure 1 Cross-section along the median line AA.
[0030] Figure 9 The sixth embodiment of this application is Figure 1 Cross-section along the median line AA.
[0031] Figure 10 A schematic diagram of a single insulating support member enclosing a support area provided in an embodiment of the present application.
[0032] Figure 11 A schematic diagram of a support area formed by enclosing multiple insulating support members according to an embodiment of the present application.
[0033] Figure 12 This is an overall schematic diagram of an electrical device provided in one embodiment of the present application.
[0034] Description of main component symbols 1000. Electrical equipment; 100. Secondary battery; 10. Casing; 101. Accommodation cavity; 11. First shell; 111. First wall; 112. First side wall; 1121. First surface; 12. Second shell; 121. Second wall; 122. Second side wall; 1221. Second surface; 20. Electrode assembly; 201. First tab bundle; 202. Second tab bundle; 21. First pole piece; 22. Second pole piece; 23. Diaphragm; 30. Sealing member; 301. Filling portion; 31. First adhesive layer; 32. Metal layer; 33. Second adhesive layer; 40. Insulating support member; 401. Support area; 41. Support portion; 42. Limiting portion; 50. Fixing member. DETAILED DESCRIPTION
[0035] 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 the embodiments.
[0036] 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. 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.
[0037] Unless otherwise specified, the term "plurality" as used herein means two or more than two.
[0038] The terms "first", "second", etc. are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implying the quantity, specific order or primary and secondary relationship of the technical features indicated.
[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0040] It should be understood that, taking into account actual manufacturing tolerances, in the technical solution of this application, when two components are arranged parallel or perpendicularly, the angle between the two components is allowed to have a tolerance of within 10% relative to the angle corresponding to the parallel or perpendicular arrangement. In the technical solution of this application, when two parameters are equal, a tolerance of within 10% is allowed between the two parameters.
[0041] An embodiment of the present application provides a secondary battery, comprising a housing, an electrode assembly, a seal, and an insulating support. The housing comprises a first shell and a second shell, the first shell and the second shell being insulated and forming a receiving cavity together, the receiving cavity being filled with electrolyte, the first shell comprising a first wall and a first side wall connected to the periphery of the first wall, the second shell comprising a second wall and a second side wall connected to the periphery of the second wall, the first side wall being provided with a first surface, the first surface facing the second side wall along the extension direction of the first side wall, the second side wall being provided with a second surface, the second surface facing the first side wall along the extension direction of the second side wall, the first surface and the second surface being arranged opposite to each other and having a gap. The electrode assembly is arranged in the receiving cavity, the positive electrode of the electrode assembly is electrically connected to the first shell, and the negative electrode of the electrode assembly is electrically connected to the second shell. The seal is arranged around the periphery of the first side wall and the second side wall, and seals the gap, the seal comprising a filling portion arranged in the gap. The insulating support member is at least partially located in the gap, and the filling portion and the insulating support member jointly fill the gap. When viewed from the inside of the receiving cavity toward the outside and perpendicular to the assembly direction of the first shell and the second shell, at least a portion of the filling portion and the insulating support member do not overlap. The melting point of the insulating support member is greater than that of the filling portion.
[0042] In the secondary battery of the present application, by positioning the filling portion of the sealing member within the gap and at least partially positioning the insulating support member within the gap, the filling portion and the insulating support member can jointly separate the first and second shells, thereby facilitating the insulation between the first and second shells. By ensuring that the melting point of the insulating support member is greater than that of the filling portion, even if the filling portion melts due to a rise in the internal temperature of the secondary battery, the insulating support member can still separate the first and second shells, thereby mitigating the risk of a short circuit in the secondary battery.
[0043] The following will describe some embodiments of the present application 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.
[0044] See also Figures 1 to 11 The embodiment of the present application provides a secondary battery 100, including a housing 10, an electrode assembly 20, a sealing member 30, and an insulating support member 40. The electrode assembly 20 is accommodated in the housing 10. The sealing member 30 is provided on the outer wall of the housing 10 and is used to seal the housing 10. The insulating support member 40 is provided on the side wall of the housing 10 and is connected to the sealing member 30.
[0045] In some embodiments, see Figure 2 and Figure 3 The housing 10 includes a first shell 11 and a second shell 12, and the first shell 11 and the second shell 12 are insulated from each other. In some embodiments, the housing 10 is a metal housing, and the material of the housing 10 includes at least one of a steel alloy, an aluminum alloy, and a copper alloy. The material of the first shell 11 and the material of the second shell 12 can be the same or different.
[0046] In some embodiments, see Figure 3 The 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 has a first surface 1121, which faces the second side wall 122 along the extension direction of the first side wall 112. The second side wall 122 has a second surface 1221, which faces the first side wall 112 along the extension direction of the second side wall 122. The first surface 1121 and the second surface 1221 are arranged to face each other, and a gap is formed between the first surface 1121 and the second surface 1221.
[0047] See also Figures 4 to 9 The first shell 11 and the second shell 12 together form a receiving cavity 101, which is filled with electrolyte and the electrode assembly 20 is disposed in the receiving cavity 101. Figure 3The electrode assembly 20 includes a first electrode piece 21 , a second electrode piece 22 and a diaphragm 23 . The second electrode piece 22 has a polarity opposite to that of the first electrode piece 21 . The diaphragm 23 separates the first electrode piece 21 from the second electrode piece 22 .
[0048] In some embodiments, see Figures 4 to 9 The electrode assembly 20 is a stacked structure, in which a plurality of first electrode sheets 21 and a plurality of second electrode sheets 22 are alternately stacked, wherein the diaphragm 23 is provided between any adjacent first electrode sheets 21 and second electrode sheets 22 .
[0049] In some embodiments, the electrode assembly 20 is a wound structure, in which a single first electrode sheet 21 and a single second electrode sheet 22 are stacked and wound, wherein the separator 23 is disposed between the first electrode sheet 21 and the second electrode sheet 22 .
[0050] In some embodiments, the first electrode sheet 21 is a negative electrode sheet, and the second electrode sheet 22 is a positive electrode sheet. In some embodiments, the first electrode sheet 21 is a positive electrode sheet, and the second electrode sheet 22 is a negative electrode sheet. Along the thickness direction of the electrode assembly 20, the projection of the negative electrode sheet overlaps the projection of the positive electrode sheet.
[0051] In some embodiments, the first pole piece 21 includes a first current collector and a first active material layer, with the first active material layer disposed on two opposing surfaces of the first current collector along the thickness direction. The second pole piece 22 includes a second current collector and a second active material layer, with the second active material layer disposed on two opposing surfaces of the second current collector along the thickness direction. In some embodiments, when the first pole piece 21 or the second pole piece 22 is the outermost pole piece of the electrode assembly 20, the active material layer may not be disposed on the side of the current collector facing away from the interior of the electrode assembly 20.
[0052] In some embodiments, the material of the first current collector includes at least one of copper, nickel, tantalum, and titanium, and the material of the second current collector includes at least one of aluminum, nickel, tantalum, and titanium.
[0053] In some embodiments, the material of the first active material layer includes at least one of graphite, hard carbon, soft carbon, silicon, silicon-oxygen material, and silicon-carbon material. The material of the second 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.
[0054] In some embodiments, the diaphragm 23 is made of insulating film materials such as polyethylene film, polypropylene film, polyester film, or polyimide film.
[0055] In some embodiments, the positive electrode of the electrode assembly 20 is electrically connected to the first shell 11, and the negative electrode of the electrode assembly 20 is electrically connected to the second shell 12. The first shell 11 and the second shell 12 are insulated, which is beneficial to reduce the risk of short circuit of the secondary battery 100. In some embodiments, please refer to Figure 3 The secondary battery 100 further includes a plurality of first tabs connected to the first electrode sheet 21, which are gathered together to form a first tab bundle 201. The secondary battery 100 further includes a plurality of second tabs connected to the second electrode sheet 22, which are gathered together to form a second tab bundle 202. The first tab bundle 201 is electrically connected to the first housing 11, and the second tab bundle 202 is electrically connected to the second housing 12.
[0056] In some embodiments, the seal 30 is used to separate and seal the first housing 11 and the second housing 12. Figure 1 and Figure 2 At least a portion of the seal 30 is disposed around the outer periphery of the first sidewall 112 and the second sidewall 122. Along the thickness direction of the seal 30, the projection of the seal 30 at least partially overlaps with the projections of the first shell 11 and the second shell 12. The seal 30 includes a filling portion 301 disposed in the gap between the first sidewall 112 and the second sidewall 122. The filling portion 301 can separate the first shell 11 and the second shell 12, thereby facilitating the insulation between the first and second shells 11, 12. In some embodiments, a portion of the seal 30 melts and enters the gap between the first and second sidewalls 112, 122, and upon cooling, forms the filling portion 301.
[0057] See also Figures 4 to 9 , the insulating support member 40 is provided on the side wall of the housing 10 and is connected to the sealing member 30. The insulating support member 40 is at least partially located in the gap, and the filling portion 301 and the insulating support member 40 jointly fill the gap. By arranging the filling portion 301 of the sealing member 30 in the gap and the insulating support member 40 at least partially located in the gap, the filling portion 301 and the insulating support member 40 jointly fill the gap, and the filling portion 301 and the insulating support member 40 can jointly separate the first shell 11 and the second shell 12, which is beneficial to the insulation setting of the first shell 11 and the second shell 12. When observing from the inside to the outside of the receiving cavity 101 and perpendicular to the assembly direction of the first shell 11 and the second shell 12, at least part of the filling portion 301 does not overlap with the insulating support member 40, and the melting point of the insulating support member 40 is greater than the melting point of the filling portion 301. By ensuring that at least a portion of the filling portion 301 does not overlap with the insulating support member 40 when viewed from the inside of the receiving cavity 101 and perpendicular to the assembly direction of the first shell 11 and the second shell 12, and the melting point of the insulating support member 40 is greater than that of the filling portion 301, if the filling portion 301 melts due to a rise in the internal temperature of the secondary battery 100, the insulating support member 40 can still separate the first shell 11 and the second shell 12. The filling portion 301 can also melt and release pressure at high temperatures, which helps reduce the risk of short circuits in the secondary battery 100. In some embodiments, the insulating support member 40 comprises an insulating material.
[0058] In some embodiments, see Figures 4 to 9 The sealing member 30 includes a first adhesive layer 31, which is adhered to the outer periphery of the first side wall 112 and the second side wall 122. The filling portion 301 is connected to the first adhesive layer 31. The adhesion of the first adhesive layer 31 to the first side wall 112 and the second side wall 122 helps to improve the stability of the adhesion between the sealing member 30 and the housing 10.
[0059] In some embodiments, the filling portion 301 is integrally formed with the first adhesive layer 31. The filling portion 301 can be formed directly by melting a portion of the first adhesive layer 31, entering the gap between the first side wall 112 and the second side wall 122, and then cooling. This can simplify the assembly process of the secondary battery 100 and facilitate the process flow for manufacturing the secondary battery 100. Furthermore, the filling portion 301 is integrally formed with the first adhesive layer 31, fully fitting the gap between the first side wall 112 and the second side wall 122, thereby improving the sealing performance of the seal 30 between the first shell 11 and the second shell 12. In other embodiments, the filling portion 301 is provided separately from the first adhesive layer 31.
[0060] In some embodiments, the first adhesive layer 31 can melt or lose adhesion when heated, and forms part of a pressure relief channel connected to the receiving cavity 101. When the secondary battery 100 experiences thermal runaway, the melting or loss of adhesion of the first adhesive layer 31 can promptly relieve pressure in the receiving cavity 101, thereby improving the safety of the secondary battery 100.
[0061] In some embodiments, the melting point of the first adhesive layer 31 is between 95°C and 130°C. For example, the melting point of the first adhesive layer 31 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 31 to between 95°C and 130°C, the possibility of premature melting or loss of adhesion of the first adhesive layer 31 before thermal runaway of the secondary battery 100 occurs can be reduced, which helps maintain the sealing effect of the seal 30 on the outer shell 10. Furthermore, it can ensure that the first adhesive layer 31 melts or loses adhesion in time to relieve pressure in the receiving cavity 101 when thermal runaway of the secondary battery 100 occurs, which helps improve the safety of the secondary battery 100.
[0062] It should be understood that when the filling portion 301 is integrally provided with the first adhesive layer 31, and the filling portion 301 is directly formed by a portion of the first adhesive layer 31 melting and entering the gap between the first side wall 112 and the second side wall 122 and then cooling, the melting point of the filling portion 301 is substantially the same as the melting point of the first adhesive layer 31. The melting point of the filling portion 301 is T1, 95°C ≤ T1 ≤ 130°C. By setting 95°C ≤ T1 ≤ 130°C, the possibility of the filling portion 301 prematurely melting before thermal runaway of the secondary battery 100 occurs can be reduced, which is beneficial for maintaining the sealing effect of the sealing member 30 on the outer shell 10. In addition, it can ensure that when thermal runaway of the secondary battery 100 occurs, the filling portion 301 melts in time to relieve the pressure of the receiving cavity 101, which is beneficial for improving the safety of the secondary battery 100.
[0063] In some embodiments, the material of the first adhesive layer 31 comprises an electrolyte-resistant polymer. The polymer comprises at least one of polyolefin, fluororubber, and polyurethane. Polyolefins may include polypropylene and polyethylene, among others. This allows the first adhesive layer 31 to have high resistance to electrolyte corrosion. In some embodiments, the first adhesive layer 31 comprises a single layer or multiple layers of the polymer.
[0064] In some embodiments, see Figures 4 to 9 The seal 30 includes a metal layer 32, which is arranged on the side of the first adhesive layer 31 away from the outer shell 10. The water resistance of the metal layer 32 is better than that of the first adhesive layer 31, which is beneficial to improving the sealing performance of the seal 30 to the first shell 11 and the second shell 12.
[0065] In some embodiments, the material of metal layer 32 includes at least one of steel, aluminum, nickel, silver, copper, and alloys thereof. In some embodiments, metal layer 32 is a single layer or a multilayer structure. For example, the multilayer structure includes a steel layer plus an aluminum layer, or a nickel layer plus a copper layer.
[0066] In some embodiments, see Figures 4 to 9 The sealing member 30 includes a second adhesive layer 33, which is disposed on a side of the metal layer 32 facing away from the first adhesive layer 31. The second adhesive layer 33 can protect the metal layer 32, thereby reducing the risk of damage and failure of the metal layer 32.
[0067] In some embodiments, the melting point of the second adhesive layer 33 is greater than the melting point of the first adhesive layer 31. In some embodiments, the difference in melting point between the second adhesive layer 33 and the first adhesive layer 31 is greater than 10°C.
[0068] In some embodiments, the melting point of the second adhesive layer 33 is 140° C. to 500° C. For example, the melting point of the second adhesive layer 33 is 140° C., 160° C., 200° C., 250° C., 300° C., 500° C., or any value therebetween.
[0069] In some embodiments, the material of the second adhesive layer 33 comprises an electrolyte-resistant polymer. The polymer may include at least one of polyolefins, fluoropolymers, polyetheretherketones, fluororubbers, and polyurethanes. Polyolefins may include polypropylene and polyethylene, while fluoropolymers may include polytetrafluoroethylene. This allows the second adhesive layer 33 to have high resistance to electrolyte corrosion. In some embodiments, the second adhesive layer 33 comprises a single or multiple layers of the polymer.
[0070] It should be understood that when the seal 30 includes a first adhesive layer 31, a metal layer 32, and a second adhesive layer 33, the first adhesive layer 31 and the second adhesive layer 33 are respectively disposed on either side of the metal layer 32 along the thickness direction of the metal layer 32. In some embodiments, the first adhesive layer 31 and the metal layer 32, as well as the second adhesive layer 33 and the metal layer 32, are fixed by gluing, so that the first adhesive layer 31, the metal layer 32, and the second adhesive layer 33 are fixed by hot pressing, so that the first adhesive layer 31, the metal layer 32, and the second adhesive layer 33 are fixed by hot pressing, so that the first adhesive layer 31, the metal layer 32, and the second adhesive layer 33 are fixed by hot pressing. This helps maintain the sealing performance of the seal 30 against the first shell 11 and the second shell 12 during long-term use of the secondary battery 100.
[0071] In some embodiments, along the thickness direction of the sealant 30, the first adhesive layer 31 has a thickness d1, the metal layer 32 has a thickness d2, and the second adhesive layer 33 has a thickness d3. The following conditions are met: 7 μm ≤ d1 ≤ 500 μm, 7 μm ≤ d2 ≤ 250 μm, and 6 μm ≤ d3 ≤ 500 μm. For example, d1 is 7 μm, 10 μm, 20 μm, 50 μm, 100 μm, 200 μm, 500 μm, or any value therebetween; d2 is 7 μm, 10 μm, 20 μm, 50 μm, 100 μm, 150 μm, 250 μm, or any value therebetween; and d3 is 6 μm, 8 μm, 20 μm, 50 μm, 100 μm, 200 μm, 500 μm, or any value therebetween. By setting d1 to 7μm ≤ d1, d2 to 7μm ≤ d2, and d3 to 6μm ≤ d3, the first adhesive layer 31, metal layer 32, and second adhesive layer 33 are kept from being too thin, thereby reducing the risk of first adhesive layer 31 being corroded and failing by the electrolyte. This also reduces the risk of second adhesive layer 33 breaking after the secondary battery 100 is dropped, leading to damage and failure of the metal layer 32, or corrosion and failure of the metal layer 32. By setting d1 to 500μm ≤ 250μm, and d3 to 500μm, the first adhesive layer 31, metal layer 32, and second adhesive layer 33 are kept from being too thick, thereby increasing the energy density of the secondary battery 100.
[0072] 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 31, metal layer 32, and second adhesive layer 33 can be made thicker, further reducing the risk of first adhesive layer 31 being corroded and failing by the electrolyte. This also helps reduce the risk of second adhesive layer 33 being damaged after the secondary battery 100 is dropped, leading to damage and failure of the metal layer 32, or failure of the metal layer 32 due to corrosion. 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 31 is substantially sufficient to prevent failure due to electrolyte corrosion, the thickness of the second adhesive layer 33 is sufficient to withstand most drops, and the thickness of the metal layer 32 is substantially sufficient to prevent failure due to damage or corrosion.
[0073] In some embodiments, the thickness of the first adhesive layer 31 can be uniform or non-uniform. In some embodiments, the thickness of the metal layer 32 can be uniform or non-uniform. In some embodiments, the thickness of the second adhesive layer 33 can be uniform or non-uniform. In some embodiments, the thickness of the seal 30 can be uniform or non-uniform, and the thickness of the seal 30 is equal to the sum of the thicknesses of the first adhesive layer 31, the metal layer 32, and the second adhesive layer 33.
[0074] In some embodiments, the melting point of the insulating support member 40 is T2, and T2>150° C. Setting T2>150° C. can help reduce the risk of the insulating support member 40 melting when the filling portion 301 melts.
[0075] In some embodiments, the insulating support member 40 is integrally provided with the filling portion 301. This helps to improve the stability of the connection between the insulating support member 40 and the filling portion 301. In some embodiments, the filling portion 301 is fused to the insulating support member 40 while molten, and after cooling, the filling portion 301 and the insulating support member 40 are integrally provided.
[0076] In some embodiments, the Young's modulus of the insulating support member 40 is greater than or equal to 500 MPa, which is beneficial for the insulating support member 40 to have a better supporting effect.
[0077] In some embodiments, the number of insulating supports 40 is several, and the so-called several means one or more. Observed along the assembly direction of the first shell 11 and the second shell 12, the several insulating supports 40 and the connecting lines between two adjacent ends of the several insulating supports 40 along the circumferential direction of the seal 30 enclose a support area 401. For example, see Figure 10When there is only one insulating support member 40, the so-called support area 401 can be determined by the following method: from the perspective of the assembly direction of the first shell 11 and the second shell 12, a straight line is drawn to connect the two ends of the insulating support member 40, and the closed area enclosed by the straight line and the insulating support member 40 itself is the support area 401. In some embodiments, if the insulating support member 40 itself is a closed figure when viewed along the assembly direction of the first shell 11 and the second shell 12, the closed area enclosed by the insulating support member 40 itself is the support area 401. For another example, refer to Figure 11 When the number of insulating support members 40 is two or more, the so-called support area 401 can be determined by the following method: from the perspective of the assembly direction of the first shell 11 and the second shell 12, a straight line is drawn to connect the two adjacent ends of each two insulating support members 40 adjacent to each other along the circumferential direction of the seal 30. The closed area enclosed by the straight line and the multiple insulating support members 40 themselves is the support area 401.
[0078] In some embodiments, when viewed along the assembly direction of the first shell 11 and the second shell 12, the area of the support region 401 is S1, the projected area of the housing 10 is S2, and 0.3 ≤ S1 / S2 ≤ 1. For example, the value of S1 / S2 is 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or any value between the listed endpoints. By setting 0.3 ≤ S1 / S2 ≤ 1, the area of the support region 401 is not too small. If the filling portion 301 melts due to the increased internal temperature of the secondary battery 100, the possibility of the first shell 11 or the second shell 12 tilting toward the position where the filling portion 301 was before melting, resulting in contact between the first shell 11 and the second shell 12, can be reduced, thereby further reducing the risk of a short circuit in the secondary battery 100.
[0079] In some embodiments, when viewed along the assembly direction of the first and second shells 11, 12, the support region 401 covers the center of gravity of the first and second shells 11, 12. Enabling the support region 401 to cover the center of gravity of the first and second shells 11, 12 reduces the possibility of the first and second shells 11, 12 tilting toward the position where the filling portion 301 was located before melting, leading to contact between the first and second shells 11, 12, if the filling portion 301 melts due to a rise in the internal temperature of the secondary battery 100. This further reduces the risk of a short circuit in the secondary battery 100.
[0080] In some embodiments, see Figures 4 to 9The insulating support member 40 includes a support portion 41 provided in the gap and a limiting portion 42 connected to the support portion 41. In some embodiments, the insulating support member 40 is provided on the first side wall 112, and along the wall thickness direction of the first side wall 112, the projection of the limiting portion 42 at least partially overlaps with the projection of the first side wall 112. In some embodiments, the insulating support member 40 is provided on the second side wall 122, and along the wall thickness direction of the second side wall 122, the projection of the limiting portion 42 at least partially overlaps with the projection of the second side wall 122. By providing the limiting portion 42, the supporting effect of the insulating support member 40 can be improved. If the filling portion 301 melts due to the increase in the internal temperature of the secondary battery 100, it is beneficial to keep the first shell 11 and the second shell 12 stable.
[0081] In some embodiments, see Figure 4 and Figure 5 , along the assembly direction of the first shell 11 and the second shell 12, the limiting portion 42 is only provided at one end of the insulating support member 40 close to the first side wall 112. It should be understood that in some embodiments, along the assembly direction of the first shell 11 and the second shell 12, the limiting portion 42 is only provided at one end of the insulating support member 40 close to the second side wall 122. In some embodiments, please refer to Figure 6 and Figure 7 Along the assembly direction of the first shell 11 and the second shell 12 , the limiting portions 42 are provided at both ends of the insulating support member 40 .
[0082] In some embodiments, see Figure 4 , the limiting portion 42 is only provided on the inner wall of the first side wall 112. It should be understood that in some embodiments, the limiting portion 42 is only provided on the outer wall of the first side wall 112. In some embodiments, please refer to Figure 5 The limiting portion 42 is provided on the inner wall and the outer wall of the first side wall 112 . It should be understood that in some embodiments, the limiting portion 42 is provided on the inner wall and / or the outer wall of the second side wall 122 .
[0083] In some embodiments, see Figure 8 and Figure 9 The insulating support member 40 is disposed on the first side wall 112 and the second side wall 122. That is, the insulating support member 40 is disposed on the first side wall 112 and the insulating support member 40 is disposed on the second side wall 122. The insulating support member 40 disposed on the first side wall 112 and the insulating support member 40 disposed on the second side wall 122 are disposed separately. This allows the insulating support member 40 to adapt to the first side wall 112 and the second side wall 122 respectively. This helps reduce the possibility of deformation of the insulating support member 40 under stress when there is an assembly error between the first shell 11 and the second shell 12.
[0084] In some embodiments, see Figure 9The insulating support member 40 and the filling portion 301 are stacked along the assembly direction of the first shell 11 and the second shell 12 to jointly fill the gap. Along the assembly direction of the first shell 11 and the second shell 12, one surface of the insulating support member 40 contacts the first sidewall 112 or the second sidewall 122, while the other surface of the insulating support member 40 contacts the filling portion 301. This helps reduce the possibility of short circuits between the first shell 11 and the second shell 12 due to burr contact. In some embodiments, the projection of the insulating support member 40 overlaps with the projection of the filling portion 301 along the assembly direction of the first shell 11 and the second shell 12.
[0085] In some embodiments, the insulating support member 40 and the filling portion 301 are stacked along the assembly direction of the first shell 11 and the second shell 12 to jointly fill the gap. The insulating support member 40 is an insulating coating, and the material of the insulating coating includes at least one of an inorganic non-metallic material, a fluoropolymer, and a thermosetting resin. The so-called inorganic non-metallic material includes, but is not limited to, ceramics and glass. The so-called fluoropolymer includes, but is not limited to, polytetrafluoroethylene, fluorinated ethylene propylene, and polyvinylidene fluoride. The so-called thermosetting resin includes, but is not limited to, epoxy resin. In some embodiments, the material of the insulating support member 40 is a composite material made by mixing ceramic particles and polytetrafluoroethylene. The insulating support member 40 can be formed by applying an insulating coating, which can reduce burrs during coating, thereby reducing the possibility of short circuits between the first shell 11 and the second shell 12 due to contact between burrs. In addition, by making the insulating support member 40 include the above materials, the insulating support member 40 is beneficially provided with better insulation and support effects.
[0086] In some embodiments, the insulating support member 40 and the filling portion 301 are stacked along the assembly direction of the first shell 11 and the second shell 12 to jointly fill the gap. Along the assembly direction of the first shell 11 and the second shell 12, the thickness of the portion of the insulating support member 40 provided in the gap is D, 0.1μm≤D≤500μm. For example, D is 0.1μm, 0.5μm, 1μm, 10μm, 20μm, 50μm, 100μm, 200μm, 300μm, 500μm, or any value between the listed endpoints. By setting 0.1μm≤D≤500μm, the thickness of the insulating support member 40 is not too thin or too thick, which can ensure that the insulating support member 40 has a certain insulation effect while also helping to improve the energy density of the secondary battery 100. In some embodiments, 1μm≤D≤200μm. By setting 1 μm ≤ D ≤ 200 μm, the thickness of the insulating support member 40 is relatively appropriate, which can not only provide a good insulation effect for the insulating support member 40, but also further improve the energy density of the secondary battery 100. In addition, it is helpful to reduce the possibility of the insulating support member 40 being worn and failing during the long-term use of the secondary battery 100.
[0087] In some embodiments, see Figure 10 and Figure 11 The insulating support member 40 and the filling portion 301 are connected to each other along the circumference of the gap to fill the gap together. Along the assembly direction of the first shell 11 and the second shell 12, the two surfaces of the insulating support member 40 are in contact with the first side wall 112 and the second side wall 122 respectively, and the two surfaces of the filling portion 301 are in contact with the first side wall 112 and the second side wall 122 respectively. The insulating support member 40 and the filling portion 301 can independently support the first shell 11 and the second shell 12. If the filling portion 301 melts due to the increase in the internal temperature of the secondary battery 100, it is beneficial to keep the first shell 11 and the second shell 12 stable. In some embodiments, along the assembly direction of the first shell 11 and the second shell 12, the projection of the insulating support member 40 is separated from the projection of the filling portion 301.
[0088] In some embodiments, the insulating support member 40 and the filling portion 301 are interconnected along the circumference of the gap to jointly fill the gap. The insulating support member 40 is made of at least one of ceramic, glass, thermosetting resin, fluororubber, and mica. Thermosetting resins include, but are not limited to, epoxy resins. In some embodiments, the insulating support member 40 is made of a ceramic-based composite material or a polymer-based composite material. By making the insulating support member 40 comprise these materials, the insulating support member 40 can achieve both good insulation and support properties.
[0089] In some embodiments, the insulating support member 40 and the filling portion 301 are interconnected along the circumference of the gap to jointly fill the gap. Along the assembly direction of the first shell 11 and the second shell 12, the thickness of the portion of the insulating support member 40 provided in the gap is D, 7μm≤D≤5000μm. For example, D is 7μm, 20μm, 40μm, 100μm, 200μm, 500μm, 1000μm, 2000μm, 3000μm, 5000μm or any value between the listed endpoint values. By setting 7μm≤D≤5000μm, the thickness of the insulating support member 40 is not too thin or too thick, which can ensure that the insulating support member 40 has a certain insulation effect while also helping to improve the energy density of the secondary battery 100. In some embodiments, 40μm≤D≤3000μm. By setting 40 μm ≤ D ≤ 3000 μm, the thickness of the insulating support member 40 is relatively appropriate, which can not only provide the insulating support member 40 with a good insulation effect, but also further improve the energy density of the secondary battery 100. In addition, it is helpful to reduce the possibility of the insulating support member 40 being worn and failing during the long-term use of the secondary battery 100.
[0090] In some embodiments, see Figures 4 to 9The secondary battery 100 further includes a fixing member 50 that bonds the outer shell 10 to the electrode assembly 20, thereby reducing the risk of the electrode assembly 20 moving within the receiving cavity 101 and causing separation between the first shell 11 and / or the second shell 12 and the seal 30. In some embodiments, the fixing member 50 is disposed between the outer shell 10 and the electrode assembly 20 along the thickness direction of the electrode assembly 20. In some embodiments, the fixing member 50 is a hot melt adhesive.
[0091] See also Figure 12 One embodiment of the present application provides an electric device 1000, comprising the aforementioned secondary battery 100. Secondary battery 100 is less susceptible to short circuits, thereby extending the service life of electric device 1000. Electric 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 televisions, tape recorders, radios, cameras, tablet computers, and laptop computers.
[0092] In addition, those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present application and are not intended to limit the present application. As long as they are within the substantive 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: The housing comprises a first shell and a second shell, the first shell and the second shell being insulated from each other and jointly forming a receiving cavity filled with an electrolyte; the first shell comprising a first wall and a first side wall connected to a periphery of the first wall; the second shell comprising a second wall and a second side wall connected to a periphery of the second wall; the first side wall being provided with a first surface, the first surface facing the second side wall along an extension direction of the first side wall; the second side wall being provided with a second surface, the second surface facing the first side wall along an extension direction of the second side wall; the first surface and the second surface being arranged opposite to each other with a gap therebetween; an electrode assembly disposed in the receiving cavity; the positive electrode of the electrode assembly is electrically connected to the first shell, and the negative electrode of the electrode assembly is electrically connected to the second shell; a sealing member disposed around the outer periphery of the first side wall and the second side wall and sealing the gap; the sealing member includes a filling portion disposed in the gap; as well as An insulating support member is at least partially located in the gap, and the filling portion and the insulating support member jointly fill the gap; when observed from the inside to the outside of the accommodating cavity and perpendicular to the assembly direction of the first shell and the second shell, at least part of the filling portion does not overlap with the insulating support member, and the melting point of the insulating support member is greater than the melting point of the filling portion.
2. The secondary battery according to claim 1, wherein The secondary battery includes several insulating support members. When observed along the assembly direction of the first shell and the second shell, the several insulating support members and the connecting lines between two adjacent ends of the several insulating support members along the circumferential direction of the seal form a support area. The area of the support area is S1, the projected area of the shell is S2, and 0.3≤S1 / S2≤1.
3. The secondary battery according to claim 1, wherein The secondary battery includes a plurality of insulating support members. When viewed along the assembly direction of the first shell and the second shell, the plurality of insulating support members enclose and form a support area. The support area covers the center of gravity of the first shell and the second shell.
4. The secondary battery according to claim 1, wherein The insulating support member and the filling portion are connected to each other along a circumferential direction of the gap to jointly fill the gap.
5. The secondary battery according to claim 4, wherein The material of the insulating support member includes at least one of ceramic, glass, thermosetting resin, fluororubber and mica.
6. The secondary battery according to claim 5, characterized in that Along the assembly direction of the first shell and the second shell, the thickness of the portion of the insulating support member disposed in the gap is D, and 7 μm≤D≤5000 μm.
7. The secondary battery according to claim 6, characterized in that 40μm≤D≤3000μm.
8. The secondary battery according to claim 1, wherein The insulating support member and the filling portion are stacked along an assembly direction of the first shell and the second shell to jointly fill the gap.
9. The secondary battery according to claim 8, characterized in that The insulating support member is an insulating coating, and the material of the insulating coating includes at least one of an inorganic non-metallic material, a fluoropolymer, and a thermosetting resin.
10. The secondary battery according to claim 9, wherein Along the assembly direction of the first shell and the second shell, the thickness of the portion of the insulating support member disposed in the gap is D, and 0.1 μm≤D≤500 μm.
11. The secondary battery according to claim 10, wherein 1μm≤D≤200μm.
12. The secondary battery according to claim 1, wherein The Young's modulus of the insulating support is greater than or equal to 500 MPa.
13. The secondary battery according to claim 1, wherein The melting point of the filling portion is T1, the melting point of the insulating support member is T2, 95°C≤T1≤130°C, and T2>150°C.
14. The secondary battery according to any one of claims 1 to 13, characterized in that The insulating support member is provided on the first side wall and the second side wall, and the insulating support member provided on the first side wall and the insulating support member provided on the second side wall are provided separately.
15. The secondary battery according to any one of claims 1 to 13, characterized in that The insulating support member includes a supporting portion arranged in the gap and a limiting portion connected to the supporting portion; the insulating support member is arranged on the first side wall, and along the wall thickness direction of the first side wall, the projection of the limiting portion at least partially overlaps with the projection of the first side wall, and / or the insulating support member is arranged on the second side wall, and along the wall thickness direction of the second side wall, the projection of the limiting portion at least partially overlaps with the projection of the second side wall.
16. An electrical device, characterized in that: The invention comprises the secondary battery according to any one of claims 1 to 15.