Secondary battery and electric device
By using an insulated housing and seals with different melting points in the secondary battery, the problems of short circuit and explosion of the housing contact at high temperatures are solved, and safety and preparation efficiency are improved.
Patent Information
- Application Number
- CN202510780561.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-11
- Publication Date
- 2025-07-18
AI Technical Summary
Existing secondary batteries are prone to short circuits in case contact due to melting of the glue layer at high temperatures, and there are hidden dangers of explosion and liquid leakage failure.
The first and second housings arranged insulated are used to achieve housing insulation and pressure relief by a combined design of the first seal and the second seal by using glue sections at different melting points, reducing the risk of short circuit and explosion.
It effectively reduces the risk of the housing short circuit and explosion of the secondary battery at high temperatures, improves the safety and energy density of the battery, and simplifies the preparation process.
Smart Images
Figure CN120341468A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of energy storage, and particularly relates to a secondary battery and an electrical device. Background Art
[0002] Current secondary batteries include steel shell batteries and soft-pack batteries. Generally, both steel shell batteries and soft-pack batteries include a housing and an electrode assembly disposed inside the housing. Among them, the housing of the steel shell battery includes a first housing body and a second housing body, and the first housing body and the second housing body are hermetically connected by welding. Summary of the Invention
[0003] Regarding the secondary batteries in the prior art, the inventors found that when the first housing body and the second housing body are respectively electrically connected to different polarities of the electrode assembly, the first housing body and the second housing body generally need to be separated by an adhesive layer to achieve insulation. However, when the internal temperature of the secondary battery rises, the adhesive layer is prone to melting, causing the first housing body and the second housing body to come into contact, thereby leading to the risk of short circuit of the secondary battery.
[0004] In view of the above situation, it is necessary to provide a secondary battery that helps reduce the risk of short circuit.
[0005] The first aspect of this application provides a secondary battery, including a housing, an electrode assembly, a first seal and a second seal. The housing includes a first housing body and a second housing body that are insulated. The first housing body and the second housing body together form a receiving cavity filled with electrolyte. The first housing body includes a first wall and a first side wall connecting the periphery of the first wall. The second housing body includes a second wall and a second side wall connecting the periphery of the second wall. The first side wall is provided with a first surface, and the first surface faces the second side wall along the extending direction of the first side wall. The second side wall is provided with a second surface, and the second surface faces the first side wall along the extending direction of the second side wall. The first surface and the second surface face each other and have a gap. The electrode assembly is disposed in the receiving cavity. The negative electrode of the electrode assembly is electrically connected to the first housing body, and the positive electrode of the electrode assembly is electrically connected to the second housing body. The first seal includes a first adhesive section and a second adhesive section, and the first adhesive section and the second adhesive section are integrally provided. The first adhesive section is wound around the outer periphery of the first side wall and the second side wall, and the second adhesive section is disposed on the side of the first adhesive section facing the receiving cavity and fills part of the gap. The part of the gap not filled by the second adhesive section forms a pressure relief hole, and the pressure relief hole communicates with the receiving cavity. The second seal is connected to the first seal. When observing from the inside of the receiving cavity to the outside along the hole depth direction of the pressure relief hole, the pressure relief hole at least partially overlaps with the second seal, and the melting point of the second seal is lower than the melting point of the first seal.
[0006] The first glue segment is wound around the outer perimeters of the first sidewall and the second sidewall. The second glue segment fills part of the gap between the first surface and the second surface. The second glue segment can separate the first housing and the second housing, which is beneficial to insulating the first housing and the second housing. Since the melting point of the second seal is lower than that of the first seal, when the second seal melts due to the increase in the internal temperature of the secondary battery, the secondary battery can exhaust and relieve pressure through the pressure relief hole, which is beneficial to reducing the risk of explosion caused by excessive internal pressure of the secondary battery. Moreover, compared with the second seal, the first seal has a higher melting point. When the second seal melts, the second glue segment can still separate the first housing and the second housing, which is beneficial to reducing the risk of short circuit in the secondary battery.
[0007] In one or more of the above embodiments, the second seal includes a third glue segment and a fourth glue segment, and the third glue segment and the fourth glue segment are integrally provided. The number of winding turns of the first glue segment is less than one turn. Along the winding direction of the first glue segment, the third glue segment connects the two ends of the first glue segment, and the fourth glue segment connects the two ends of the second glue segment. The third glue segment and the first glue segment are jointly wound around the outer perimeters of the first sidewall and the second sidewall, and the fourth glue segment and the second glue segment jointly fill the gap. The second seal seals the pressure relief hole. In this case, the fourth glue segment and the second glue segment can jointly separate the first housing and the second housing, which is more beneficial to insulating the first housing and the second housing. Moreover, the first seal and the second seal jointly seal the gap between the first surface and the second surface, which is beneficial to reducing the risk of liquid leakage failure in the secondary battery.
[0008] In one or more of the above embodiments, along the thickness direction of the first glue segment, at least part of the third glue segment is stacked on the side of the first glue segment facing away from the receiving cavity and is fixedly provided with the first glue segment. In this case, the connection area between the third glue segment and the first glue segment can be increased, and the connection stability between the third glue segment and the first glue segment can be improved. Thereby, it is beneficial to reducing the risk of liquid leakage failure in the secondary battery caused by the disconnection of the two ends of the third glue segment and the first glue segment along the winding direction under the dropping condition or during long-term use.
[0009] In one or more of the above embodiments, the number of winding turns of the first adhesive segment is greater than one. The first adhesive segment is provided with a through hole communicating with the pressure relief hole. The second seal member individually seals the through hole, or the second seal member and the first seal member jointly seal the through hole. When observing along the hole depth direction of the through hole from the inside of the receiving cavity to the outside of the receiving cavity, the through hole and the second seal member at least partially overlap. When encapsulating through the first seal member and the second seal member, the first adhesive segment provided with the through hole can be wound around the outer perimeters of the first side wall and the second side wall first, and the second adhesive segment can fill part of the gap between the first surface and the second surface. Then, the second seal member individually seals the through hole of the first adhesive segment, or the second seal member and the first seal member jointly seal the through hole of the first adhesive segment. This is beneficial to simplifying the process of connecting the first seal member and the second seal member and improving the preparation efficiency of the secondary battery. Moreover, it is beneficial to improving the sealing performance of the first seal member and the second seal member to the outer shell.
[0010] In one or more of the above embodiments, the part of the first adhesive segment located in the outermost winding is the trailing end of the first adhesive segment, and the second seal member is connected to the end of the trailing end along the winding direction of the first adhesive segment. In this case, along the direction perpendicular to the assembly direction of the first housing and the second housing, it is beneficial to reduce the space occupied by the first seal member and the second seal member and improve the energy density of the secondary battery.
[0011] In one or more of the above embodiments, the part of the first adhesive segment located in the outermost winding is the trailing end of the first adhesive segment. Along the hole depth direction of the through hole, at least part of the second seal member is stacked on the side of the through hole facing away from the receiving cavity, and at least part of the trailing end is stacked on the side of the second seal member facing away from the receiving cavity. The trailing end can play a certain protective role for the second seal member, which is beneficial to reducing the risk that the second seal member is damaged in advance under unexpected conditions (such as a drop condition), resulting in the leakage and failure of the secondary battery.
[0012] In one or more of the above embodiments, when observing along the assembly direction of the first housing and the second housing, the second adhesive segment and the connection line between the two ends of the second adhesive segment enclose a support area, and the projection of the support area covers the centers of gravity of the first housing and the second housing. When the second seal member melts due to the increase in the internal temperature of the secondary battery, the second adhesive segment can support the first housing or the second housing, which is beneficial to reducing the possibility that the first housing tilts towards the second housing or the second housing tilts towards the first housing, resulting in contact between the first housing and the second housing, and is beneficial to further reducing the risk of short circuit of the secondary battery.
[0013] In one or more of the above embodiments, the outer shell is provided with corner portions, part of the corner portions are located on the first side wall and part of the corner portions are located on the second side wall, and the pressure relief hole is located at the corner portion. In this case, the second seal member can utilize the space at the position of the corner portion, which is beneficial to improving the energy density of the secondary battery.
[0014] In one or more of the above embodiments, the secondary battery further includes a tab, and the tab is connected to the electrode assembly. Along the extending direction of the tab, the corner portion is located on the side of the housing close to the tab. In this case, along the extending direction of the tab, the distance between the electrode assembly and the housing is relatively large, and at this time, the distance between the pressure relief hole located at the corner portion and the electrode assembly can be made relatively large. When the second sealant melts due to the increase in the internal temperature of the secondary battery, the efficiency of the secondary battery exhausting and relieving pressure through the pressure relief hole can be improved, which is beneficial to further reducing the risk of explosion caused by excessive internal pressure of the secondary battery.
[0015] In one or more of the above embodiments, the melting point of the first sealant is T1, and the melting point of the second sealant is T2, where 150°C ≤ T1 ≤ 500°C and 95°C ≤ T2 ≤ 130°C. By setting 95°C ≤ T2 ≤ 130°C, the possibility of the second sealant melting in advance before the secondary battery undergoes thermal runaway can be reduced, which is beneficial to maintaining the sealing effect of the second sealant on the pressure relief hole. Moreover, it can ensure that the second sealant melts in time to relieve the pressure of the accommodating cavity when the secondary battery undergoes thermal runaway, which is beneficial to improving the safety of the secondary battery. By setting 150°C ≤ T1 ≤ 500°C, the risk of the first sealant melting when the second sealant melts can be reduced.
[0016] In the second aspect of the present application, an electrical device is provided, including the secondary battery of the first aspect of the present application. The secondary battery is not prone to short circuit, which is beneficial to improving the safety of the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 It is a top view of the secondary battery provided by an embodiment of the present application.
[0018] Figure 2 It is a front view of the secondary battery provided by an embodiment of the present application.
[0019] Figure 3 It is an exploded view of the secondary battery provided by an embodiment of the present application.
[0020] Figure 4 It is a sectional view of the first embodiment of the present application along Figure 2 section line A-A.
[0021] Figure 5 It is a sectional view of the second embodiment of the present application along Figure 2 section line A-A.
[0022] Figure 6 It is a sectional view of the third embodiment of the present application along Figure 2 section line A-A.
[0023] Figure 7This is a cross-sectional view of the fourth embodiment of the present application along Figure 2 the cross-sectional line A-A in the middle.
[0024] Figure 8 This is an overall schematic diagram of an electrical device provided by an embodiment of the present application.
[0025] Main component symbol description 1000, electrical device; 100, secondary battery; 101, accommodation cavity; 102, pressure relief hole; 103, corner part; 11, first housing; 111, first wall; 112, first side wall; 1121, first surface; 12, second housing; 121, second wall; 122, second side wall; 1221, second surface; 20, electrode assembly; 30, first seal; 31, first glue segment; 311, tail part; 312, through hole; 32, second glue segment; 321, support area; 33, metal layer; 34, protective layer; 40, second seal; 41, third glue segment; 42, fourth glue segment; 50, tab; 501, negative tab bundle; 502, positive tab bundle; 51, negative tab; 52, positive tab. Detailed implementation manners
[0026] Next, the technical solutions in the embodiments of the present application will be described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.
[0027] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element. When an element is considered to be "disposed on" another element, it can be directly disposed on the other element or there may be an intermediate element.
[0028] Unless otherwise specified, the term "a plurality" used herein means two or more.
[0029] Terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features.
[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the description of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.
[0031] It should be understood that considering the factors of actual processing tolerances, in the technical solution of the present application, when two components are arranged in parallel / vertical, the included angle between the two components is allowed to have a tolerance within the range of 10% of the included angle corresponding to the parallel / vertical arrangement.
[0032] The present application provides a secondary battery, including a housing, an electrode assembly, a first seal and a second seal. The housing includes a first housing and a second housing which are insulated. The first housing and the second housing together form a receiving cavity filled with an electrolyte. The first housing includes a first wall and a first side wall connecting the periphery of the first wall. The second housing includes a second wall and a second side wall connecting the periphery of the second wall. The first side wall is provided with a first surface, and the first surface faces the second side wall along the extending direction of the first side wall. The second side wall is provided with a second surface, and the second surface faces the first side wall along the extending direction of the second side wall. The first surface and the second surface face each other and have a gap. The electrode assembly is disposed in the receiving cavity. The negative electrode of the electrode assembly is electrically connected to the first housing, and the positive electrode of the electrode assembly is electrically connected to the second housing. The first seal includes a first glue segment and a second glue segment which are integrally provided. The first glue segment is wound around the outer peripheries of the first side wall and the second side wall. The second glue segment is disposed on the side of the first glue segment facing the receiving cavity and fills part of the gap. The part of the gap not filled by the second glue segment forms a pressure relief hole, and the pressure relief hole communicates with the receiving cavity. The second seal is connected to the first seal. When observing from the inside of the receiving cavity to the outside along the hole depth direction of the pressure relief hole, the pressure relief hole at least partially overlaps with the second seal, and the melting point of the second seal is less than the melting point of the first seal.
[0033] In the secondary battery of the present application, by winding the first glue segment around the outer peripheries of the first side wall and the second side wall, and filling part of the gap between the first surface and the second surface with the second glue segment, the second glue segment can separate the first housing and the second housing, which is beneficial to the insulated arrangement of the first housing and the second housing. Since the melting point of the second seal is less than the melting point of the first seal, when the second seal melts due to the increase in the internal temperature of the secondary battery, the secondary battery can exhaust and relieve pressure through the pressure relief hole, which is beneficial to reducing the risk of explosion caused by excessive internal pressure of the secondary battery. Moreover, compared with the second seal, the first seal has a higher melting point. When the second seal melts, the second glue segment can still separate the first housing and the second housing, which is beneficial to reducing the risk of short circuit of the secondary battery.
[0034] Hereinafter, some embodiments of the present application will be described in conjunction with the drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.
[0035] Please refer to Figures 1 to 3, an embodiment of the present application provides a secondary battery 100, which includes a housing 10, an electrode assembly 20, a first seal 30, and a second seal 40. The electrode assembly 20 is accommodated in the housing 10, and the first seal 30 and the second seal 40 jointly seal the housing 10.
[0036] In some embodiments, please refer to Figure 2 and Figure 3 , the housing 10 includes a first housing 11 and a second housing 12, and the first housing 11 and the second housing 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 steel alloy, aluminum alloy, and copper alloy. Among them, the materials of the first housing 11 and the second housing 12 may be the same or different.
[0037] In some embodiments, please refer to Figure 3 , the first housing 11 includes a first wall 111 and a first side wall 112, the second housing 12 includes a second wall 121 and a second side wall 122, the first side wall 112 is connected to the periphery of the first wall 111, and the second side wall 122 is connected to the periphery of the second wall 121. The first side wall 112 is provided with a first surface 1121, the first surface 1121 faces the second side wall 122 along the extending direction of the first side wall 112, the second side wall 122 is provided with a second surface 1221, the second surface 1221 faces the first side wall 112 along the extending direction of the second side wall 122, the first surface 1121 and the second surface 1221 are arranged opposite to each other, and there is a gap between the first surface 1121 and the second surface 1221.
[0038] In some embodiments, please refer to Figure 1 and Figure 3 , the housing 10 is provided with a corner portion 103, and a part of the corner portion 103 is located on the first side wall 112 and a part of the corner portion 103 is located on the second side wall 122. Among them, the first side wall 112 includes at least two wall surfaces that are sequentially connected along the periphery of the first wall 111 and are arranged at an angle. Along the assembly direction of the first housing 11 and the second housing 12, the connection transition position of the two wall surfaces of the first side wall 112 forms a part of the corner portion 103. The second side wall 122 includes at least two wall surfaces that are sequentially connected along the periphery of the second wall 121 and are arranged at an angle. Along the assembly direction of the first housing 11 and the second housing 12, the connection transition position of the two wall surfaces of the second side wall 122 forms a part of the corner portion 103.
[0039] Please refer to Figures 4 to 7 , the first housing 11 and the second housing 12 jointly form a receiving cavity 101, the receiving cavity 101 is filled with electrolyte, the electrode assembly 20 is arranged in the receiving cavity 101, the negative electrode of the electrode assembly 20 is connected to the first housing 11, and the positive electrode of the electrode assembly 20 is connected to the second housing 12. Please refer to Figure 3, the electrode assembly 20 includes a negative electrode tab, a positive electrode tab, and a separator (not shown in the figure). The positive electrode tab and the negative electrode tab are arranged alternately, and the separator separates the negative electrode tab and the positive electrode tab.
[0040] In some embodiments, the electrode assembly 20 has a laminated structure, and the negative electrode tab and the positive electrode tab are alternately laminated. The separator is disposed between adjacent negative and positive electrode tabs. In some embodiments, the electrode assembly 20 has a wound structure, and the negative electrode tab and the positive electrode tab are alternately wound. The separator is disposed between the negative electrode tab and the positive electrode tab.
[0041] In some embodiments, the negative electrode tab includes a negative current collector and a negative active material layer, and the negative active material layer is disposed on at least one surface of the negative current collector in the thickness direction. The positive electrode tab includes a positive current collector and a positive active material layer, and the positive active material layer is disposed on at least one surface of the positive current collector opposite to each other in the thickness direction. In some embodiments, when the negative electrode tab or the positive electrode tab is the outermost tab of the electrode assembly 20, the surface of the current collector facing away from the inside of the electrode assembly 20 may not be provided with an active material layer. The materials of the negative current collector include, but are not limited to, copper, nickel, tantalum, and titanium. The materials of the positive current collector include, but are not limited to, aluminum, nickel, tantalum, and titanium. The materials of the negative active material layer include, but are not limited to, graphite, hard carbon, soft carbon, silicon, silicon oxide materials, and silicon-carbon materials. The materials of the positive active material layer include, but are not limited to, lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium iron phosphate, lithium manganese iron phosphate, and lithium manganate. The separator includes, but is not limited to, insulating film materials such as polyethylene film, polypropylene film, polyester film, and polyimide film.
[0042] Please refer to Figures 4 to 7 , in some embodiments, the first seal 30 includes a first glue segment 31. The first glue segment 31 includes an insulating material. The first glue segment 31 is wound around the outer peripheries of the first sidewall 112 and the second sidewall 122. The number of winding turns of the first glue segment 31 can be less than, equal to, or greater than one turn. For example, the number of winding turns of the first glue segment 31 is one-third turn, one-half turn, three-quarters turn, one turn, three-halves turn, or two turns, etc. Among them, when the number of winding turns of the first glue segment 31 is greater than one turn, the part of the first glue segment 31 located in the outermost winding is the tail part 311 of the first glue segment 31, and the tail part 311 is fixedly arranged with the part of the first glue segment 31 located in the second outermost winding. Along the direction perpendicular to the assembly direction of the first housing 11 and the second housing 12, the projection of the first glue segment 31 overlaps at least partially with the projections of the first sidewall 112 and the second sidewall 122.
[0043] Please refer to Figures 4 to 7, in some embodiments, the first seal 30 includes a second glue segment 32. The second glue segment 32 includes an electrolyte-resistant insulating material, and the insulating material of the second glue segment 32 includes an electrolyte-resistant polymer, such as at least one of polyolefin, fluoropolymer, polyetheretherketone, fluororubber, and polyurethane. Among them, polyolefin may include polypropylene, polyethylene, etc., and fluoropolymer may be polytetrafluoroethylene, etc. The second glue segment 32 is disposed on the side of the first glue segment 31 facing the receiving cavity 101 and fills part of the gap between the first surface 1121 and the second surface 1221. The second glue segment 32 can separate the first housing 11 and the second housing 12, which is beneficial to the insulating arrangement of the first housing 11 and the second housing 12.
[0044] In some embodiments, the first glue segment 31 and the second glue segment 32 are integrally provided. The first seal 30 can be first wound around the outer periphery of the first side wall 112 and the second side wall 122, and then a part of the first seal 30 is melted and enters the gap between the first surface 1121 and the second surface 1221. After cooling, the part of the first seal 30 that remains wound around the outer periphery of the first side wall 112 and the second side wall 122 is the first glue segment 31, and the part of the first seal 30 that fills the gap between the first surface 1121 and the second surface 1221 is the second glue segment 32. In some embodiments, the first seal 30 is clamped by a heating instrument and heat is transferred to the first seal 30, and a part of the first seal 30 is melted and activated at high temperature, so that the melted part of the first seal 30 enters the gap between the first surface 1121 and the second surface 1221. Among them, parameters such as the heating temperature or power of the heating instrument are adjustable. It should be understood that high temperature refers to a temperature greater than or equal to the melting point of the first seal 30. By adjusting the position where the heating instrument clamps the first seal 30, the filling condition of the second glue segment 32 can be adjusted. The so-called filling condition refers to the filling position, filling ratio, etc. of the second glue segment 32 filling the gap between the first surface 1121 and the second surface 1221.
[0045] Please refer to Figures 4 to 7 , the part of the gap between the first surface 1121 and the second surface 1221 that is not filled by the second glue segment 32 forms a pressure relief hole 102, and the pressure relief hole 102 communicates with the receiving cavity 101. Among them, Figures 4 to 7 The dashed line in [Figure] shows the outer wall contours of the first side wall 112 and the second side wall 122 when viewed along the assembly direction of the first housing 11 and the second housing 12. The second seal 40 is connected to the first seal 30 and seals the pressure relief hole 102. The second seal 40 includes an electrolyte-resistant insulating material, and the insulating material of the second seal 40 includes an electrolyte-resistant polymer, such as at least one of polyolefin, fluororubber, and polyurethane. Among them, polyolefin may include polypropylene, polyethylene, etc.
[0046] Looking from the inside of the accommodation cavity 101 to the outside along the hole depth direction of the pressure relief hole 102, the pressure relief hole 102 at least partially overlaps with the second seal 40. Among them, the melting point of the second seal 40 is less than the melting point of the first seal 30. Through the pressure relief hole 102 of the second seal 40, and the melting point of the second seal 40 is less than the melting point of the first seal 30. When the second seal 40 melts due to the increase in the internal temperature of the secondary battery 100, the secondary battery 100 can exhaust and relieve pressure through the pressure relief hole 102, which is beneficial to reducing the risk of explosion caused by excessive internal pressure of the secondary battery 100. Moreover, compared with the second seal 40, the first seal 30 has a higher melting point. When the second seal 40 melts, the second glue segment 32 can still separate the first housing 11 and the second housing 12, which is beneficial to reducing the risk of short circuit of the secondary battery 100.
[0047] In some embodiments, please refer to Figure 4 , the pressure relief hole 102 is located at the corner portion 103. In this case, the second seal 40 can utilize the space at the position of the corner portion 103, which is beneficial to improving the energy density of the secondary battery 100.
[0048] In some embodiments, looking along the assembly direction of the first housing 11 and the second housing 12, the second glue segment 32 and the connection line between the two ends of the second glue segment 32 enclose a support area 321. For example, please refer to Figure 4 , the so-called support area 321 can be determined in the following way: from the perspective of the assembly direction of the first housing 11 and the second housing 12, draw a straight line ( Figure 4 the dotted line in) to connect the two ends of the second glue segment 32, and the enclosed area formed by the drawn straight line and the second glue segment 32 itself is the support area 321.
[0049] In some embodiments, the projection of the support area 321 covers the centers of gravity of the first housing 11 and the second housing 12. When the second seal 40 melts due to the increase in the internal temperature of the secondary battery 100, the second glue segment 32 can support the first housing 11 (when the first housing 11 is above the second glue segment 32 along the gravity direction) or the second housing 12 (when the second housing 12 is above the second glue segment 32 along the gravity direction), which is beneficial to reducing the possibility that the first housing 11 tilts towards the second housing 12 or the second housing 12 tilts towards the first housing 11, resulting in contact between the first housing 11 and the second housing 12, and is beneficial to further reducing the risk of short circuit of the secondary battery 100.
[0050] In some embodiments, when observed along the assembly direction of the first housing 11 and the second housing 12, the area of the support region 321 is S1, and the projected area of the outer housing 10 is S2, where 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 endpoint values. By setting 0.3 ≤ S1 / S2 ≤ 1, when the second seal 40 melts due to the increase in the internal temperature of the secondary battery 100, the possibility of the first housing 11 tilting towards the second housing 12 or the second housing 12 tilting towards the first housing 11, resulting in contact between the first housing 11 and the second housing 12, can be reduced, which is beneficial to further reducing the risk of short circuit in the secondary battery 100.
[0051] In some embodiments, the melting point of the first seal 30 is T1, and the melting point of the second seal 40 is T2, where 150°C ≤ T1 ≤ 500°C and 95°C ≤ T2 ≤ 130°C. For example, T1 is 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 500°C, or any value between the listed endpoint values, and T2 is 95°C, 100°C, 110°C, 120°C, 130°C, or any value between the listed endpoint values. It can be understood that the melting points of the first glue segment 31 and the second glue segment 32 are the same as T1. By setting 95°C ≤ T2 ≤ 130°C, the possibility of the second seal 40 melting prematurely before the secondary battery 100 undergoes thermal runaway can be reduced, which is beneficial to maintaining the sealing effect of the second seal 40 on the pressure relief hole 102. Moreover, it can ensure that when the secondary battery 100 undergoes thermal runaway, the second seal 40 melts in a timely manner to relieve the pressure in the accommodation cavity 101, which is beneficial to improving the safety of the secondary battery 100. By setting 150°C ≤ T1 ≤ 500°C, the risk of the first seal 30 melting when the second seal 40 melts can be reduced.
[0052] Please refer to Figure 4 or Figure 5, in some embodiments, the number of winding turns of the first glue segment 31 is less than one turn. The second seal 40 includes a third glue segment 41 and a fourth glue segment 42. It can be understood that the melting points of the third glue segment 41 and the fourth glue segment 42 correspond to T2 and are the same. Along the winding direction of the first glue segment 31, the third glue segment 41 connects the two ends of the first glue segment 31, and the fourth glue segment 42 connects the two ends of the second glue segment 32. The third glue segment 41 and the first glue segment 31 are jointly wound around the outer peripheries of the first side wall 112 and the second side wall 122, and the fourth glue segment 42 and the second glue segment 32 jointly fill the gap between the first surface 1121 and the second surface 1221. The second seal 40 seals the pressure relief hole 102. In this case, the fourth glue segment 42 and the second glue segment 32 can jointly separate the first housing 11 and the second housing 12, which is more conducive to insulating the first housing 11 and the second housing 12. Moreover, the first seal 30 and the second seal 40 jointly seal the gap between the first surface 1121 and the second surface 1221, which is beneficial to reducing the risk of liquid leakage failure of the secondary battery 100. In some embodiments, the third glue segment 41 and the fourth glue segment 42 are integrally provided. The second seal 40 can be first wound around the outer peripheries of the first side wall 112 and the second side wall 122, and then a part of the second seal 40 is melted and enters the gap between the first surface 1121 and the second surface 1221. After cooling, the part of the second seal 40 that remains wound around the outer peripheries of the first side wall 112 and the second side wall 122 is the third glue segment 41, and the part of the second seal 40 that fills the gap between the first surface 1121 and the second surface 1221 is the fourth glue segment 42.
[0053] Please refer to Figure 5 , in some embodiments, the number of winding turns of the first glue segment 31 is less than one turn. Along the thickness direction of the first glue segment 31, at least part of the third glue segment 41 is stacked on the side of the first glue segment 31 facing away from the receiving cavity 101 and is fixedly arranged with the first glue segment 31. In this case, the connection area between the third glue segment 41 and the first glue segment 31 can be increased, and the connection stability between the third glue segment 41 and the first glue segment 31 can be improved. Thus, it is beneficial to reduce the risk of liquid leakage failure of the secondary battery 100 caused by the disconnection of the two ends of the third glue segment 41 and the first glue segment 31 along the winding direction under the drop condition or during long-term use.
[0054] Please refer to Figure 6 or Figure 7, in some embodiments, the number of winding turns of the first glue segment 31 is greater than one. The first glue segment 31 is provided with a through hole 312 communicating with the pressure relief hole 102, and the second seal 40 seals the through hole 312 alone or the second seal 40 and the first seal 30 jointly seal the through hole 312. Among them, a plurality of winding turns of the first glue segment 31 can be provided with through holes 312 and communicate with each other. Looking from the inner side of the receiving cavity 101 to the outside of the receiving cavity 101 along the hole depth direction of the through hole 312, the through hole 312 and the second seal 40 at least partially overlap. When encapsulating through the first seal 30 and the second seal 40, the first glue segment 31 provided with the through hole 312 can be wound around the outer peripheries of the first side wall 112 and the second side wall 122 first, and the second glue segment 32 can be used to fill part of the gap between the first surface 1121 and the second surface 1221, and then the second seal 40 seals the through hole 312 of the first glue segment 31 alone or the second seal 40 and the first seal 30 jointly seal the through hole 312 of the first glue segment 31, which is beneficial to simplifying the process of connecting the first seal 30 and the second seal 40 and improving the preparation efficiency of the secondary battery 100. Moreover, it is beneficial to improve the sealing performance of the first seal 30 and the second seal 40 to the housing 10.
[0055] Please refer to Figure 6 , in some embodiments, the number of winding turns of the first glue segment 31 is greater than one. The second seal 40 is connected to the end of the receiving tail portion 311 along the winding direction of the first glue segment 31. In this case, along the direction perpendicular to the assembly direction of the first housing 11 and the second housing 12, it is beneficial to reduce the space occupied by the first seal 30 and the second seal 40 and improve the energy density of the secondary battery 100.
[0056] Please refer to Figure 7 , in some embodiments, the number of winding turns of the first glue segment 31 is greater than one. Along the hole depth direction of the through hole 312, at least part of the second seal 40 is stacked on the side of the through hole 312 away from the receiving cavity 101, and at least part of the receiving tail portion 311 is stacked on the side of the second seal 40 away from the receiving cavity 101. The receiving tail portion 311 can play a certain protective role on the second seal 40, which is beneficial to reducing the risk that the second seal 40 is damaged in advance under unexpected conditions (such as dropping conditions) and causing the secondary battery 100 to leak and fail.
[0057] In some embodiments, please refer to Figure 3, the secondary battery 100 further includes a tab 50, and the tab 50 is connected to the electrode assembly 20. The tab 50 includes a negative tab 51 and a positive tab 52, the negative tab 51 is connected to the negative current collector of the negative electrode sheet, and the positive tab 52 is connected to the positive current collector of the positive electrode sheet. In some embodiments, the number of negative tabs 51 is multiple, the number of positive tabs 52 is multiple, the multiple negative tabs 51 are gathered to form a negative tab bundle 501, the multiple positive tabs 52 are gathered to form a positive tab bundle 502, the negative tab bundle 501 is electrically connected to the first shell 11, and the positive tab bundle 502 is electrically connected to the second shell 12.
[0058] In some embodiments, along the extension direction of the pole tab 50, the corner portion 103 is located on the side of the housing 10 close to the pole tab 50. In this case, along the extension direction of the pole tab 50, the distance between the electrode assembly 20 and the housing 10 is large, and at this time, the distance between the pressure relief hole 102 located at the corner portion 103 and the electrode assembly 20 can be large. When the second sealing member 40 melts due to the increase in the internal temperature of the secondary battery 100, the efficiency of the secondary battery 100 in exhausting and venting through the pressure relief hole 102 can be improved, which is conducive to further reducing the risk of explosion caused by excessive internal pressure of the secondary battery 100.
[0059] In some embodiments, along the extension direction of the negative electrode tab 51, the corner portion 103 is located on the side of the housing 10 close to the tab 50. In some embodiments, along the extension direction of the positive electrode tab 52, the corner portion 103 is located on the side of the housing 10 close to the tab 50. The extension direction of the negative electrode tab 51 and the extension direction of the positive electrode tab 52 may be the same or different.
[0060] In some embodiments, see Figures 4 to 7 The first sealing member 30 includes a metal layer 33, which is disposed on the side of the first rubber segment 31 away from the housing 10. The water barrier property of the metal layer 33 is better than that of the first rubber segment 31, which is beneficial to improving the sealing property of the first sealing member 30 to the first housing 11 and the second housing 12.
[0061] In some embodiments, see Figure 4 The number of turns of the first rubber segment 31 is less than one turn. The second sealing member 40 includes a third rubber segment 41 and a fourth rubber segment 42. Along the winding direction of the first rubber segment 31, the third rubber segment 41 connects the two ends of the first rubber segment 31, and the fourth rubber segment 42 connects the two ends of the second rubber segment 32. At least part of the metal layer 33 is disposed on the side of the first rubber segment 31 and the third rubber segment 41 away from the receiving cavity 101.
[0062] In some embodiments, see Figure 5, the number of winding turns of the first adhesive segment 31 is less than one turn. Along the thickness direction of the first adhesive segment 31, at least part of the third adhesive segment 41 is stacked on the side of the first adhesive segment 31 facing away from the accommodation cavity 101 and is fixedly arranged with the first adhesive segment 31, and at least part of the metal layer 33 is arranged on the side of the first adhesive segment 31 and the third adhesive segment 41 facing away from the accommodation cavity 101.
[0063] In some embodiments, please refer to Figure 6 , the number of winding turns of the first adhesive segment 31 is greater than one turn. The first adhesive segment 31 and the metal layer 33 are both provided with through holes 312 communicating with the pressure relief hole 102. The second seal 40 individually seals the through holes 312 or the second seal 40 and the first seal 30 jointly seal the through holes 312. The second seal 40 is connected to the end of the receiving tail portion 311 along the winding direction of the first adhesive segment 31. Along the depth direction of the through hole 312, at least part of the second seal 40 is stacked on the side of the through hole 312 facing away from the accommodation cavity 101, and at least part of the metal layer 33 is arranged on the side of the receiving tail portion 311 and the second seal 40 facing away from the accommodation cavity 101.
[0064] In some embodiments, please refer to Figure 7 , the number of winding turns of the first adhesive segment 31 is greater than one turn. Along the depth direction of the through hole 312, at least part of the second seal 40 is stacked on the side of the through hole 312 facing away from the accommodation cavity 101, at least part of the receiving tail portion 311 is stacked on the side of the second seal 40 facing away from the accommodation cavity 101, and at least part of the metal layer 33 is stacked on the side of the receiving tail portion 311 facing away from the accommodation cavity 101.
[0065] In some embodiments, the material of the metal layer 33 includes at least one of steel, aluminum, nickel, silver, copper, and their alloys. In some embodiments, the metal layer 33 has a single-layer or multi-layer structure. For example, the multi-layer structure is a steel layer plus an aluminum layer or a nickel layer plus a copper layer, etc.
[0066] In some embodiments, please refer to Figures 4 to 7 , the first seal 30 includes a protective layer 34, and the protective layer 34 is arranged on the side of the metal layer 33 facing away from the first adhesive segment 31. The protective layer 34 can protect the metal layer 33, which is beneficial to reducing the risk of the metal layer 33 being damaged and failing.
[0067] In some embodiments, please refer to Figure 4 , the number of winding turns of the first adhesive segment 31 is less than one turn. The second seal 40 includes a third adhesive segment 41 and a fourth adhesive segment 42. Along the winding direction of the first adhesive segment 31, the third adhesive segment 41 connects the two ends of the first adhesive segment 31, the fourth adhesive segment 42 connects the two ends of the second adhesive segment 32, at least part of the metal layer 33 is arranged on the side of the first adhesive segment 31 and the third adhesive segment 41 facing away from the accommodation cavity 101, and at least part of the protective layer 34 is arranged on the side of the metal layer 33 facing away from the accommodation cavity 101.
[0068] In some embodiments, referring to Figure 5 , the number of winding turns of the first adhesive segment 31 is less than one turn. Along the thickness direction of the first adhesive segment 31, at least part of the third adhesive segment 41 is stacked on the side of the first adhesive segment 31 facing away from the receiving cavity 101 and is fixedly arranged with the first adhesive segment 31. At least part of the metal layer 33 is arranged on the side of the first adhesive segment 31 and the third adhesive segment 41 facing away from the receiving cavity 101, and at least part of the protective layer 34 is arranged on the side of the metal layer 33 facing away from the receiving cavity 101.
[0069] In some embodiments, referring to Figure 6 , the number of winding turns of the first adhesive segment 31 is greater than one turn. The first adhesive segment 31, the metal layer 33, and the protective layer 34 are all provided with through holes 312 communicating with the pressure relief hole 102. The second seal 40 individually seals the through holes 312 or the second seal 40 and the first seal 30 jointly seal the through holes 312. The second seal 40 is connected to the end of the receiving tail portion 311 along the winding direction of the first adhesive segment 31. Along the hole depth direction of the through hole 312, at least part of the second seal 40 is stacked on the side of the through hole 312 facing away from the receiving cavity 101. At least part of the metal layer 33 is arranged on the side of the receiving tail portion 311 and the second seal 40 facing away from the receiving cavity 101, and at least part of the protective layer 34 is arranged on the side of the metal layer 33 facing away from the receiving cavity 101.
[0070] In some embodiments, referring to Figure 7 , the number of winding turns of the first adhesive segment 31 is greater than one turn. Along the hole depth direction of the through hole 312, at least part of the second seal 40 is stacked on the side of the through hole 312 facing away from the receiving cavity 101. At least part of the receiving tail portion 311 is stacked on the side of the second seal 40 facing away from the receiving cavity 101. At least part of the metal layer 33 is stacked on the side of the receiving tail portion 311 facing away from the receiving cavity 101, and at least part of the protective layer 34 is arranged on the side of the metal layer 33 facing away from the receiving cavity 101.
[0071] In some embodiments, the material of the protective layer 34 includes a polymer resistant to electrolytes, such as at least one of polyolefins, fluoropolymers, polyetheretherketone, fluororubber, and polyurethane. Among them, polyolefins may include polypropylene, polyethylene, etc., and fluoropolymers may be, for example, polytetrafluoroethylene, etc.
[0072] In some embodiments, the melting point of the protective layer 34 is 140°C to 500°C. For example, the melting point of the protective layer 34 is 140°C, 160°C, 200°C, 250°C, 300°C, 500°C, or any value between the listed endpoint values.
[0073] In some embodiments, the secondary battery 100 further includes a fixing member (not shown in the figure). The fixing member bonds the housing 10 and the electrode assembly 20, which is beneficial to reducing the risk that the electrode assembly 20 moves in the accommodation cavity 101, resulting in the peeling of the first housing 11 and / or the second housing 12 from the first sealing member 30 and the second sealing member 40. The fixing member includes, but is not limited to, hot melt adhesive. In some embodiments, the fixing member is disposed between the housing 10 and the electrode assembly 20 along the thickness direction of the electrode assembly 20.
[0074] Please refer to Figure 8 , an embodiment of the present application provides an electrical device 1000, including the secondary battery 100 as described above. The secondary battery 100 is not prone to short circuit, which is beneficial to improving the safety 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, liquid crystal TVs, tape recorders, radios, cameras, tablet computers, and laptop computers.
[0075] In addition, those of ordinary skill in the art in this technical field should recognize that the above embodiments are only used to illustrate the present application, rather than to limit the present application. As long as it is within the substantial scope of the present application, appropriate changes and variations made to the above embodiments fall 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 which are insulated, the first shell and the second shell together forming a receiving cavity, the receiving cavity being filled with electrolyte; the first shell comprises a first wall and a first side wall connected to the periphery of the first wall, the second shell comprises a second wall and a second side wall connected to the periphery of the second wall, the first side wall is provided with a first surface, the first surface faces the second side wall along the extension direction of the first side wall, the second side wall is provided with a second surface, the second surface faces the first side wall along the extension direction of the second side wall, the first surface and the second surface are arranged opposite to each other and have a gap; An electrode assembly is disposed in the receiving cavity; the negative electrode of the electrode assembly is electrically connected to the first shell, and the positive electrode of the electrode assembly is electrically connected to the second shell; A first sealing member includes a first rubber segment and a second rubber segment, wherein the first rubber segment and the second rubber segment are integrally arranged; the first rubber segment is arranged around the outer periphery of the first side wall and the second side wall, the second rubber segment is arranged on a side of the first rubber segment facing the receiving cavity and fills part of the gap, and a part of the gap not filled by the second rubber segment constitutes a pressure relief hole, and the pressure relief hole is connected to the receiving cavity; The second sealing member is connected to the first sealing member. When observed from the inside of the receiving cavity to the outside of the receiving cavity along the depth direction of the pressure relief hole, the pressure relief hole at least partially overlaps with the second sealing member. The melting point of the second sealing member is lower than that of the first sealing member.
2. The secondary battery according to claim 1, characterized in that, The second sealing component includes a third rubber segment and a fourth rubber segment, and the third rubber segment and the fourth rubber segment are integrally arranged; the number of turns of the first rubber segment is less than one turn, and along the winding direction of the first rubber segment, the third rubber segment connects the two ends of the first rubber segment, and the fourth rubber segment connects the two ends of the second rubber segment. The third rubber segment and the first rubber segment are jointly wound around the outer periphery of the first side wall and the second side wall, and the fourth rubber segment and the second rubber segment jointly fill the gap, and the second sealing component seals the pressure relief hole.
3. The secondary battery according to claim 2, characterized in that, Along the thickness direction of the first rubber segment, at least part of the third rubber segment is stacked on a side of the first rubber segment away from the receiving cavity and is fixed to the first rubber segment.
4. The secondary battery according to claim 1, characterized in that, The number of turns of the first rubber segment is greater than one turn, the first rubber segment is provided with a through hole connected to the pressure relief hole, the second sealing member seals the through hole alone or the second sealing member and the first sealing member seal the through hole together, and along the depth direction of the through hole and observed from the inside of the receiving cavity to the outside of the receiving cavity, the through hole and the second sealing member at least partially overlap.
5. The secondary battery according to claim 4, characterized in that, The first rubber segment located at the outermost winding circle is the tail portion of the first rubber segment, and the second sealing member is connected to the end of the tail portion along the winding direction of the first rubber segment.
6. The secondary battery according to claim 4, wherein The portion of the first adhesive segment located in the outermost winding is the tail portion of the first adhesive segment. Along the hole depth direction of the through hole, at least a part of the second seal is stacked on the side of the through hole facing away from the accommodation cavity, and at least a part of the tail portion is stacked on the side of the second seal facing away from the accommodation cavity.
7. The secondary battery according to claim 1, characterized in that, When observing along the assembly direction of the first housing and the second housing, the second adhesive segment and the connection line between the two ends of the second adhesive segment enclose a support area, and the projection of the support area covers the centers of gravity of the first housing and the second housing.
8. The secondary battery according to claim 1, characterized in that, The outer shell is provided with a corner portion, part of the corner portion is located on the first side wall and part of the corner portion is located on the second side wall, and the pressure relief hole is located at the corner portion.
9. The secondary battery according to claim 8, wherein, The secondary battery further includes a tab, and the tab is connected to the electrode assembly; along the extending direction of the tab, the corner portion is located on the side of the outer shell close to the tab.
10. The secondary battery according to claim 1, characterized in that, The melting point of the first seal is T1, and the melting point of the second seal is T2, where 150°C ≤ T1 ≤ 500°C and 95°C ≤ T2 ≤ 130°C.
11. An electrical device, characterized in that, A secondary battery comprising any one of claims 1 to 10.