Secondary battery, battery pack, and electronic device

Abstract

The utility model provides a secondary battery, a battery pack and an electronic device, the secondary battery comprises a shell and an electrode assembly, the shell comprises a cover plate assembly and a side wall with an opening at one end, and the cover plate assembly seals the opening; the cover plate assembly comprises a first cover plate and a second cover plate, and the first cover plate covers the opening and is in sealed connection with the side wall; the first cover plate comprises a through hole, the second cover plate at least partially shields the through hole, and the second cover plate is connected with the first cover plate; the electrode assembly is arranged in the shell, and one side, facing the opening, of the electrode assembly is provided with a first tab; wherein the first cover plate and / or the second cover plate comprise / comprises a convex part protruding towards the electrode assembly, and the convex part is supported on the first tab. According to the utility model, the core-pulling phenomenon in the use process of the secondary battery can be improved, so that the safety performance of the secondary battery is improved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a secondary battery, battery pack, and electronic device. Background Technology

[0002] During the charging and discharging process of a secondary battery, the active materials inside the electrode assembly expand or contract, causing changes in the internal pressure of the battery. If the internal pressure increases to a certain level, it may cause the electrode assembly to expand or deform, a phenomenon known as "core pulling." Core pulling can lead to problems such as deterioration of the battery interface and lithium plating, thereby worsening the battery's charging and discharging performance. In severe cases, it may even cause internal short circuits, leading to serious safety issues.

[0003] Currently, as the application range of secondary batteries becomes wider and wider, the requirements for the safety performance of secondary batteries are also increasing. Therefore, how to improve the safety performance of secondary batteries by improving the core-pulling phenomenon during the use of secondary batteries has become a technical problem that urgently needs to be solved. Utility Model Content

[0004] This invention provides a secondary battery, a battery pack, and an electronic device to improve the problem of core removal during the use of secondary batteries, thereby enhancing the safety performance of secondary batteries.

[0005] To achieve the above and other related objectives, this utility model provides a secondary battery, which includes: a housing and an electrode assembly. The housing includes a sidewall with an opening at one end and a cover plate assembly, the cover plate assembly sealing the opening; the cover plate assembly includes a first cover plate and a second cover plate, the first cover plate covering the opening and sealingly connected to the sidewall; the first cover plate includes a through hole, the second cover plate at least partially blocking the through hole, and the second cover plate being connected to the first cover plate; the electrode assembly is disposed within the housing, and the electrode assembly has a first electrode tab on the side facing the opening; wherein the first cover plate and / or the second cover plate includes a protrusion protruding toward the electrode assembly, the protrusion being supported by the first electrode tab.

[0006] In one example of the secondary battery of this utility model, the protrusion includes a first protrusion, which is disposed on the first cover plate and surrounds the first cover plate in the circumferential direction. The radial outer side of the first protrusion includes the outer peripheral surface of the protrusion, which matches the opening.

[0007] In one example of the secondary battery of this utility model, the side of the first protrusion facing the electrode assembly includes a first vent groove, which extends through the first protrusion.

[0008] In one example of the secondary battery of this utility model, the first vent groove extends radially through the first protrusion; the depth of the first vent groove is T1, and T1 is within the range of 0.03 to 0.4 mm; the width of the first vent groove is W1, and W1 is within the range of 2 to 8 mm.

[0009] In one example of the secondary battery of this utility model, the second cover plate includes an injection hole. Along the radial direction of the first cover plate, a portion of the second cover plate extends between the first cover plate and the first electrode tab, and another portion extends between the through hole and the first electrode tab and cooperates with the inner wall of the through hole to form a stepped stage. The cover plate assembly also includes a sealing plate. The outer periphery of the sealing plate cooperates with the stepped stage and is welded to the inner wall of the through hole to seal the injection hole.

[0010] In one example of the secondary battery of this utility model, the protrusion further includes a second protrusion, which is disposed in the area where the second cover extends to the first cover and the first electrode tab.

[0011] In one example of the secondary battery of this utility model, the second protrusion is arranged around the second cover plate in the circumferential direction, and the side of the second protrusion facing the electrode assembly includes a second vent groove, which penetrates the second protrusion.

[0012] In one example of the secondary battery of this utility model, the second vent groove penetrates the second protrusion radially along the second protrusion; the depth of the second vent groove is T2, and T2 is in the range of 0.03 to 0.4 mm; the width of the second vent groove is W2, and W2 is in the range of 2 to 8 mm.

[0013] In one example of the secondary battery of this utility model, the protrusion further includes a third protrusion, which is disposed in the area between the through hole and the first electrode tab of the second cover plate, and is disposed around the second cover plate in the circumferential direction.

[0014] In one example of the secondary battery of this utility model, the electrode assembly includes a core through hole. Along the radial direction of the second cover plate, the distance between the third protrusion and the edge of the core through hole is W3, and W3 is between 0.2 and 10 mm.

[0015] In one example of the secondary battery of this utility model, a current collecting member is provided between the electrode assembly and the cover plate assembly. The current collecting member includes a body part and a thickened part. The thickened part is located radially inside the second protrusion. The thickened part protrudes relative to the body part toward the cover plate assembly and abuts against the second cover plate.

[0016] In one example of the secondary battery of this utility model, the electrode assembly includes a core through hole. Along the radial direction of the second cover plate, the distance between the thickened part and the edge of the core through hole is W4, and W4 is between 0.2 and 10 mm.

[0017] This utility model also provides a battery pack, which includes any of the above-mentioned secondary batteries.

[0018] This invention further provides an electronic device that includes the aforementioned battery pack.

[0019] This utility model of a secondary battery features protrusions on a first cover plate and / or a second cover plate, which are supported by a first electrode tab. This arrangement creates a support relationship between the cover plate assembly and the electrode assembly. When the electrode assembly expands and deforms, the cover plate assembly restricts the deformation of the first electrode tab, reducing the amount of deformation caused by the expansion of the first electrode tab towards the opening side. This improves the core-pulling phenomenon of the electrode assembly and reduces the probability of short circuits caused by the positive and negative electrode plates at the first electrode tab coming into contact due to displacement, thereby improving the safety performance of the secondary battery. Furthermore, since the cover plate assembly includes a separate first cover plate and a second cover plate, which can be formed separately and then fixedly connected, compared to a one-piece end cap design, this design allows for the optimized layout of multiple local feature structures on the cover plate assembly by adjusting the connection position between the first and second cover plates. This facilitates the processing and forming of local features. Therefore, the separate design of the cover plate assembly in this solution offers greater flexibility and facilitates the forming of the protrusions on the first or second cover plate. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a cross-sectional view of the overall structure of an example of a secondary battery of this utility model;

[0022] Figure 2 for Figure 1 A magnified view of a portion of region A in the middle;

[0023] Figure 3 This is a schematic diagram of the electrode assembly structure of an example of the secondary battery of this utility model;

[0024] Figure 4 This is a schematic diagram of the cover plate assembly in an example of the secondary battery of this utility model;

[0025] Figure 5 for Figure 4 A magnified view of a portion of region 5 in the middle;

[0026] Figure 6 This is a partial structural diagram of the sealing plate with the liquid injection hole not covered in an example of the secondary battery of this utility model;

[0027] Figure 7 This is a partial structural diagram of a secondary battery example of the present invention, in which both the second cover plate and the first cover plate are provided with protrusions.

[0028] Figure 8 This is a schematic diagram of the cover plate assembly in another example of the secondary battery of this utility model;

[0029] Figure 9 A partially enlarged view of an example of a secondary battery of this utility model, showing that both the first and second cover plates have protrusions.

[0030] Figure 10 This is a partial structural diagram of a second cover plate with a third protrusion in an example of the secondary battery of this utility model.

[0031] Figure 11 A partial structural diagram of a current collector component with a thickened portion is shown in an example of a secondary battery of this utility model.

[0032] Figure 12 This is a schematic diagram of an example of the battery pack of this utility model;

[0033] Figure 13 This is a schematic diagram of an example of the electronic device of this utility model.

[0034] Component designation explanation

[0035] 100. Secondary battery; 110. Casing; 111. Opening; 112. Side wall; 113. End wall; 120. Cover assembly; 121. First cover plate; 1211. Through hole; 122. Second cover plate; 1221. Injection hole; 123. Sealing plate; 1331. Solder mark; 124. Stage; 130. Electrode assembly; 131. Positive electrode; 1311. Positive current collector; 1312. First coated area; 1313. First uncoated area; 132. Separator; 133. Negative electrode; 1331. Negative current collector; 1332. Second coated area; 1333. 134. Uncoated area; 135. Second tab; 136. Core through hole; 140. Protrusion; 141. First protrusion; 1411. Outer peripheral surface of protrusion; 142. First vent groove; 143. Second protrusion; 144. Second vent groove; 145. Third protrusion; 146. Third vent groove; 150. Current collector; 151. Body; 1511. Opening; 152. Thickened part; 160. Electrode terminal; 200. Battery pack; 210. Housing; 211. First housing part; 212. Second housing part; 300. Electronic device; 310. Working part. Detailed Implementation

[0036] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. It should also be understood that the terminology used in the embodiments of this utility model is for describing specific implementation schemes and not for limiting the scope of protection of this utility model. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0037] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of this invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to those described, used, or made of materials in the embodiments of this invention.

[0038] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" used in this specification are only for clarity of description and are not intended to limit the scope of implementation of this utility model. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as within the scope of implementation of this utility model.

[0039] Please see Figures 1 to 13 This utility model provides a secondary battery 100, a battery pack 200, and an electronic device 300. The cover plate assembly 120 of the secondary battery 100 is provided with a protrusion 140, which supports the tabs of the electrode assembly 130. Therefore, when the electrode assembly 130 expands and deforms, the amount of expansion and deformation of the tabs towards the opening 111 can be reduced, the core pulling phenomenon of the electrode assembly 130 can be improved, and the safety performance of the secondary battery 100 can be enhanced.

[0040] In this invention, the secondary battery 100 may include lithium-ion batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this invention are not limited to this. The secondary battery 100 may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this invention are not limited to this either.

[0041] Please see Figure 1The structure of the secondary battery 100 is further described, which includes a housing 110 and an electrode assembly 130.

[0042] The housing 110 has a mounting cavity for mounting the electrode assembly 130, electrolyte (not shown), and other components. Specifically, the dimensions of the housing 110 can be determined based on the specific dimensions of the electrode assembly 130, for example, a diameter of 46 mm and heights of 80 mm, 95 mm, or 120 mm. The housing 110 can be of various shapes, such as cylindrical or prismatic. The housing 110 can also be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy. To prevent rusting during long-term use, a rust-preventive material, such as nickel, can be plated onto the surface of the housing 110.

[0043] Please see Figure 1 and Figure 2 In one embodiment of the secondary battery 100 of this utility model, the housing 110 has a cylindrical structure and includes an end wall 113, a side wall 112 surrounding the end wall 113, and a cover plate assembly 120. Along the height direction of the housing 110, one end of the side wall 112 is fixedly connected to the end wall 113 to form a closed end, and the other end of the side wall 112 is provided with an opening 111. The cover plate assembly 120 is disposed at the opening 111 and seals the opening 111.

[0044] Please see Figure 1 and Figure 3 The electrode assembly 130 is disposed inside the housing 110 and is a component in the secondary battery 100 where electrochemical reactions occur. The housing 110 may contain one or more electrode assemblies 130. The electrode assembly 130 includes an electrode sheet and a separator 132, which are wound together to form a wound structure. Specifically, in this embodiment, the electrode assembly 130 includes a positive electrode sheet 131, a separator 132, and a negative electrode sheet 133 wound axially around the housing 110.

[0045] Please see Figure 3 The positive electrode 131 includes a positive current collector 1311 and a positive active material layer coated on the positive current collector 1311. A first coated area 1312 coated with the positive active material layer and a first uncoated area 1313 uncoated with the positive active material layer are formed on the positive current collector 1311. The first coated area 1312 and the first uncoated area 1313 are arranged along the axial direction of the housing 110. The first uncoated area 1313 extends to one end of the secondary battery 100 in the height direction to the outside of the separator 132 and is bent towards the axis of the housing 110 to form a stacked positive electrode tab.

[0046] Please continue reading. Figure 3The negative electrode 133 includes a negative current collector 1331 and a negative active material layer coated on the negative current collector 1331. A second coated area 1332 coated with the negative active material layer and a second uncoated area 1333 uncoated with the negative active material layer are formed on the negative current collector 1331. The second coated area 1332 and the second uncoated area 1333 are arranged along the axial direction of the housing 110. The second uncoated area 1333 extends to the other end of the secondary battery 100 in the height direction to the outside of the separator 132 and is bent towards the axis of the housing 110 to form a stacked negative electrode tab.

[0047] Please continue reading. Figure 3 A separator 132 is disposed between the positive electrode 131 and the negative electrode 133 to isolate the positive and negative active material layers. Taking a lithium-ion secondary battery 100 as an example, the positive current collector 1311 can be made of aluminum, and the positive active material layer includes positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative current collector 1331 can be made of copper, and the negative active material layer includes negative active material, which can be carbon or silicon, etc. The substrate material of the separator 132 can be polypropylene (PP) or polyethylene (PE), etc. To protect and insulate the electrode assembly 130, an insulating film can also be wrapped around the electrode assembly 130. The insulating film can be synthesized from PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other polymer materials.

[0048] Please continue reading. Figure 1 and Figure 2 In one example of the secondary battery 100 of this utility model, the electrode assembly 130 is sealed and installed inside the housing 110. The electrode assembly 130 has a first tab 135 and a second tab 134 respectively provided at both ends in the height direction of the secondary battery 100, and the first tab 135 and the second tab 134 have opposite polarities. The first tab 135 faces the opening 111 of the housing 110 and is the negative tab. It should be noted that in other embodiments, the first tab 135 can also be the positive tab, and the second tab 134 can be the negative tab.

[0049] Please see Figure 1In one example of the secondary battery 100 of this utility model, a through terminal mounting hole is provided on the end wall 113 of the housing 110. The electrode terminal 160 is sealed and insulatedly installed in the terminal mounting hole. As long as the electrode terminal 160 and the end wall 113 can be sealed and insulated, the installation method of the electrode terminal 160 on the end wall 113 is not limited. The electrode assembly 130 has a second tab 134 on the side facing the end wall 113. One end of the electrode terminal 160 can be directly welded to the second tab 134, or it can be electrically connected to the second tab 134 through a current collector. There are no specific restrictions on this.

[0050] Please see Figure 1 and Figure 2 The cover plate assembly 120 includes a first cover plate 121 and a second cover plate 122. The first cover plate 121 covers the opening 111, and the outer edge of the first cover plate 121 is sealed to the side wall 112 of the housing 110. Various sealing connection methods are possible, such as welding seals and mechanical pressing seals. The first cover plate 121 includes a through hole 1211, which can be located in the central region of the first cover plate 121 or off-center. The through hole 1211 can also have various shapes, such as square holes, round holes, or other irregularly shaped holes. Preferably, to facilitate the machining and positioning of the through hole 1211 on the first cover plate 121, in this embodiment, the through hole 1211 is a round hole structure, and the through hole 1211 is coaxially arranged with the first cover plate 121.

[0051] Please see Figure 2 The second cover plate 122 is disposed on one side of the first cover plate 121 and the electrode assembly 130, and the second cover plate 122 at least partially blocks the through hole 1211. The second cover plate 122 is connected to the first cover plate 121, and the connection method can be any method that can realize the electrical connection between the first cover plate 121 and the second cover plate 122, such as welding connection or riveting connection.

[0052] Please see Figure 2 Preferably, in this embodiment, the first cover plate 121 and the second cover plate 122 are welded together. The second cover plate 122 can be a disc shape that matches the through hole 1211, or it can be other shapes that can at least partially cover the through hole 1211, such as a rectangular plate, a polygonal plate, etc. Preferably, in this embodiment, the second cover plate 122 has an approximately disc-shaped structure and is coaxially arranged with the through hole 1211. This facilitates the positioning and installation of the second cover plate 122 and the first cover plate 121, and helps to improve the assembly efficiency between the second cover plate 122 and the first cover plate 121.

[0053] Please see Figure 2The cover plate assembly 120 includes a protrusion 140 on the side facing the electrode assembly 130. The protrusion 140 protrudes towards the electrode assembly 130 and is supported on the first electrode tab 135. It should be noted that the protrusion 140 may directly support the first electrode tab 135, or it may be indirectly supported on the first electrode tab 135 through a conductive element such as a current collector. Optionally, in this embodiment, please refer to... Figure 2 The secondary battery 100 also includes a current collector 150, which is disposed within the housing 110 and located on the side of the electrode assembly 130 facing the cover plate assembly 120. The current collector 150 is welded to both the first electrode tab 135 and the housing 110 to achieve electrical connection. The protrusion 140 can be a ring structure arranged around the perimeter, or a structure of multiple protrusions arranged at intervals, or any structure capable of supporting the first electrode tab 135. The current collector 150 can be welded to the cover plate assembly 120, to the side wall 112, or simultaneously to both the cover plate assembly 120 and the side wall 112. The specific position and welding area of ​​the current collector 150 to the first electrode tab 135 are not limited, as long as a stable electrical connection between the current collector 150 and the first electrode tab 135 can be achieved. The protrusion 140 abuts against the current collector 150 on the side facing the electrode assembly 130, and the current collector 150 abuts against the first electrode tab 135 below, thereby achieving indirect support between the protrusion 140 and the first electrode tab 135.

[0054] In one embodiment, the protrusion 140 may be provided on the first cover plate 121; in another embodiment, the protrusion 140 may be provided on the second cover plate 122; in other embodiments, both the first cover plate 121 and the second cover plate 122 may have protrusions 140. The protrusion 140 may be a circular ring structure coaxially arranged with the first cover plate 121, or it may be a rectangular ring structure, a polygonal ring structure, or other structures. The specific support position between the protrusion 140 and the first electrode tab 135 is not limited. For example, the protrusion 140 may be supported on the outer peripheral area of ​​the first electrode tab 135, or it may be supported on the central area of ​​the first electrode tab 135 near the electrode assembly 130.

[0055] In this embodiment, by providing protrusions 140 on the first cover plate 121 and / or the second cover plate 122, and having the protrusions 140 supported on the first tab 135, a support relationship can be formed between the cover plate assembly 120 and the electrode assembly 130. When the electrode assembly 130 expands and deforms, the cover plate assembly 120 can restrict the first tab 135, reducing the amount of expansion and deformation of the first tab 135 towards the opening 111, improving the core-pulling phenomenon of the electrode assembly 130, and reducing the probability of short circuits inside the housing 110 caused by the positive and negative electrode plates at the first tab 135 contacting each other due to displacement, thereby improving the safety performance of the secondary battery 100. Meanwhile, since the cover plate assembly 120 includes a first cover plate 121 and a second cover plate 122 that are separately set, the first cover plate 121 and the second cover plate 122 can be formed separately and then fixedly connected together. Compared with the one-piece end cap design, this design can achieve an optimized layout of multiple local feature structures on the cover plate assembly 120 by adjusting the connection position relationship between the first cover plate 121 and the second cover plate 122, so as to facilitate the processing and forming of local features. Therefore, the separate design of the cover plate assembly 120 in this embodiment is more flexible and more convenient for the protrusion 140 to be formed and set on the first cover plate 121 or the second cover plate 122.

[0056] Please see Figure 2 , Figure 4 and Figure 5 In one example of the secondary battery 100 of this utility model, the protrusion 140 includes a first protrusion 141, which is disposed on the side of the first cover plate 121 facing the electrode assembly 130. The first protrusion 141 is a ring structure circumferentially surrounding the first cover plate 121. The first protrusion 141 can be stamped from the first cover plate 121 or it can be a solid block structure welded separately to the first cover plate 121. Preferably, in this embodiment, the first protrusion 141 is stamped from the first cover plate 121. This arrangement does not increase the mass of the first cover plate 121 and can also improve the support strength of the first cover plate 121 at the first protrusion 141. The first protrusion 141 is supported on the side surface facing the electrode assembly 130 by the first tab 135. The radial outer side of the first protrusion 141 includes a protrusion outer peripheral surface 1411. The protrusion outer peripheral surface 1411 matches the shape of the opening 111 and is disposed opposite to the inner wall of the side wall 112 so as to form an abutment relationship with the inner wall of the side wall 112 in the circumferential direction.

[0057] By providing the first protrusion 141 on the first cover plate 121 and matching the outer peripheral surface 1411 of the protrusion with the opening 111, the first protrusion 141 can not only support the outer peripheral area of ​​the first electrode tab 135, limiting the expansion and deformation of the first electrode tab 135 towards the opening 111 and improving the core-pulling phenomenon of the electrode assembly 130, but also the first protrusion 141 can play a positioning role in the installation of the cover plate assembly 120 at the opening 111, improving the assembly accuracy and efficiency between the cover plate assembly 120 and the housing 110. In addition, the first protrusion 141 can also shield the welding laser when the side wall 112 is radially welded to the first cover plate 121, thereby reducing the damage of the welding laser to other internal components of the housing 110.

[0058] Considering that the first protrusion 141 supporting the first electrode tab 135 will have a certain impact on the exhaust effect at the position of the first electrode tab 135, therefore, in one example of the secondary battery 100 of this utility model, please refer to the figure. Figure 4 and Figure 5 The first protrusion 141, facing the electrode assembly 130, includes a first venting groove 142 that penetrates the first protrusion 141. The first venting groove 142 can be of various shapes, such as a rectangular groove or a U-shaped groove. The first venting groove 142 can penetrate along the radial direction of the first protrusion 141 or along other directions at an angle to the radial direction. Along the circumferential direction of the first protrusion 141, one or more first venting grooves 142 can be provided, specifically to meet the venting requirements of the secondary battery 100 at the first tab 135 end. Optionally, in this embodiment, the number of first venting grooves 142 is 2 to 16, preferably 4 to 8. Multiple first venting grooves 142 are arranged in an array along the circumferential direction of the first protrusion 141. This arrangement can achieve a relatively uniform venting effect in the circumferential direction of the first protrusion 141. In this embodiment, by providing a first venting groove 142, when the first protrusion 141 is supported on the first tab 135, a venting channel is formed at the location of the first venting groove 142. The areas on both sides of the first protrusion 141 can be interconnected through the first venting groove 142. In the event of thermal runaway of the secondary battery 100, the accumulation of high-pressure gas inside the casing 110 can be reduced, ensuring the venting effect at the end of the first tab 135, thereby achieving rapid directional pressure relief of the secondary battery 100. At the same time, due to the provision of the first venting groove 142, the support area between the first protrusion 141 and the first tab 135 can be reduced, which is beneficial to improving the venting effect of the area of ​​the first tab 135 at the support position.

[0059] To further ensure the exhaust effect at the first exhaust slot 142 position, optionally, please refer to Figure 4 and Figure 5In one example of the secondary battery 100 of this utility model, the first venting groove 142 penetrates the first protrusion 141 along the radial direction of the first protrusion 141. The depth of the first venting groove 142 is T1, and T1 is in the range of 0.03 to 0.4 mm, preferably in the range of 0.05 to 0.3 mm. For example, T1 can be 0.05 mm, 0.1 mm, 0.2 mm, or 0.3 mm. The width of the first venting groove 142 is W1, and W1 is in the range of 2 to 8 mm, preferably in the range of 3 to 6 mm. For example, W1 can be 3 mm, 5 mm, or 6 mm. In this embodiment, the first venting groove 142 penetrates the first protrusion 141 along the radial direction, which can obtain a shorter venting path, thereby increasing the venting speed of the first venting groove 142 and facilitating the rapid depressurization of the secondary battery 100. By limiting T1 to the range of 0.03 to 0.4 mm and W1 to the range of 2 to 8 mm, this setting can achieve better venting effect between the two sides of the first protrusion 141, meeting the venting and pressure relief requirements of most conventional secondary batteries 100.

[0060] Please see Figure 2 and Figure 6 In one example of the secondary battery 100 of this utility model, the second cover plate 122 includes an injection hole 1221. The injection hole 1221 can be located in the central region of the second cover plate 122 or in a region off-center from the center of the second cover plate 122, depending on whether it meets the injection requirements of the electrode assembly 130. The secondary battery 100 also includes a sealing plate 123, which is disposed on the side of the second cover plate 122 away from the current collector 150, and seals the injection hole 1221. Along the axial direction of the secondary battery 100, the second cover plate 122 is disposed between the first cover plate 121 and the current collector 150. Along the radial direction of the first cover plate 121, a portion of the second cover plate 122 extends between the first cover plate 121 and the current collector 150, and at least part of the side of the second cover plate 122 away from the electrode assembly 130 abuts against the side of the first cover plate 121 facing the electrode assembly 130. Another portion of the second cover plate 122 extends between the through hole 1211 and the current collector 150, and at least partially blocks one end of the through hole 1211 facing the electrode assembly 130, so that the second cover plate 122 mates with the inner wall of the through hole 1211 to form a platform stage 124 (e.g. Figure 6 (As shown). The outer periphery of the sealing plate 123 is accommodated within the stage 124 and mates with the stage 124. The outer periphery of the sealing plate 123 abuts against the inner wall of the through hole 1211 to form a circumferentially arranged butt joint around the through hole 1211. A weld mark 1331 is formed at the butt joint position. The sealing plate 123 is welded to the inner wall of the through hole 1211 through the weld mark 1331 to achieve the sealing of the injection hole 1221.

[0061] Since the stage 124 can be formed by the positional fit between the second cover plate 122 and the through hole 1211, the sealing plate 123 can be installed in the stage 124 to achieve the fitment of the sealing plate 123 on the cover plate assembly 120. Therefore, it is not necessary to integrally stamp the stage 124 on the first cover plate 121 or the second cover plate 122. Thus, the forming accuracy of the stage 124 can be improved, which in turn can improve the fit accuracy between the sealing plate 123 and the stage 124, and ultimately improve the welding quality between the sealing plate 123 and the stage 124, ensuring the sealing performance of the sealing plate 123 to the injection hole 1221.

[0062] Please see Figures 7 to 9 In one example of the secondary battery 100 of this utility model, the protrusion 140 further includes a second protrusion 143. The second protrusion 143 is disposed in the region where the second cover plate 122 extends to the first cover plate 121 and the current collector 150, and is arranged circumferentially around the second cover plate 122. The second protrusion 143 is disposed on the side of the second cover plate 122 facing the electrode assembly 130, and the second protrusion 143 is a ring structure arranged circumferentially around the second cover plate 122. The second protrusion 143 can be stamped from the second cover plate 122, or it can be a solid block structure welded separately to the second cover plate 122. Preferably, in this embodiment, the second protrusion 143 is stamped from the second cover plate 122. This arrangement does not increase the mass of the second cover plate 122, and at the same time, it can improve the support strength of the second cover plate 122 at the second protrusion 143. The surface of the second protrusion 143 facing the electrode assembly 130 abuts against the current collector 150, and the current collector 150 abuts against the first tab 135, thereby achieving indirect support between the second protrusion 143 and the first tab 135.

[0063] The second protrusion 143 is disposed in the region where the second cover plate 122 extends to the area between the first cover plate 121 and the first tab 135. On the one hand, since this region is the overlapping area of ​​the first cover plate 121 and the second cover plate 122, the support strength and rigidity of the cover plate assembly 120 in this region are relatively large. This can relatively increase the support strength between the second protrusion 143 and the first tab 135 located in this region, which is more conducive to controlling the deformation caused by the expansion of the first tab 135 towards the opening 111, further improving the core pulling phenomenon of the electrode assembly 130 and improving the safety performance of the secondary battery 100. On the other hand, since the second protrusion 143 is located between the first protrusion 141 and the central region of the electrode assembly 130, and this position is the area where the deformation is large when the electrode assembly 130 expands and deforms, placing the second protrusion 143 at this position can effectively limit the expansion deformation generated at the end of the first tab 135.

[0064] It should be noted that when the second cover plate 122 is provided with the second protrusion 143, in one embodiment, as follows: Figure 9 As shown, a first protrusion 141 can be provided on the first cover plate 121, thereby enabling the first protrusion 141 and the second protrusion 143 to work together, thus providing better constraint on the deformation of the first tab 135 end and further reducing the phenomenon of core pulling during the use of the secondary battery 100. In another embodiment, the first cover plate 121 may not have the first protrusion 141 provided, and the first tab 135 only forms a supporting relationship with the second protrusion 143.

[0065] Considering that the second protrusion 143 supporting the first electrode 135 will have a certain impact on the exhaust effect at the position of the first electrode 135, in an example of the secondary battery 100 of this utility model, please refer to Figure 8 and Figure 9 The second protrusion 143 includes a second venting groove 144 on the side facing the electrode assembly 130, and the second venting groove 144 penetrates the second protrusion 143. The second venting groove 144 can be of various shapes, such as a rectangular groove or a U-shaped groove. The second venting groove 144 can penetrate along the radial direction of the second protrusion 143 or along other directions at an angle to the radial direction. Along the circumferential direction of the second protrusion 143, one or more second venting grooves 144 can be provided, specifically to meet the venting requirements of the secondary battery 100 at the first tab 135 end. Optionally, in this embodiment, the number of second venting grooves 144 is 2 to 16, preferably 4 to 8. Multiple second venting grooves 144 are arranged in an array along the circumferential direction of the second protrusion 143. This arrangement can achieve a relatively uniform venting effect in the circumferential direction of the second protrusion 143. In this embodiment, by providing a second venting groove 144, when the second protrusion 143 is supported on the first tab 135, a venting channel is formed at the location of the second venting groove 144. The areas on both sides of the second protrusion 143 can be interconnected through the second venting groove 144. In the event of thermal runaway of the secondary battery 100, the accumulation of high-pressure gas inside the casing 110 can be reduced, ensuring the venting effect at the end of the first tab 135, thereby achieving rapid directional pressure relief of the secondary battery 100. At the same time, due to the provision of the second venting groove 144, the support area between the second protrusion 143 and the first tab 135 can be reduced, which is beneficial to improving the venting effect in the area of ​​the first tab 135 at the support position of the second protrusion 143.

[0066] To further ensure the exhaust effect at the second exhaust slot 144 position, optionally, please refer to Figure 8 and Figure 9In one example of the secondary battery 100 of this utility model, the second venting groove 144 penetrates the second protrusion 143 along the radial direction of the second protrusion 143; the depth of the second venting groove 144 is T2, and T2 is in the range of 0.03 to 0.4 mm, preferably in the range of 0.05 to 0.3 mm, for example, T2 can be 0.05 mm, 0.1 mm, 0.2 mm or 0.3 mm, etc. Along the radial direction of the second protrusion 143, the width of the second venting groove 144 is W2, and W2 is in the range of 2 to 8 mm, preferably in the range of 3 to 6 mm, for example, W2 can be 3 mm, 5 mm or 6 mm, etc. In this embodiment, the second venting groove 144 penetrates the second protrusion 143 along the radial direction, which can obtain a shorter venting path, thereby increasing the venting speed of the second venting groove 144, which is beneficial to the rapid depressurization of the secondary battery 100. By limiting T2 to the range of 0.03 to 0.4 mm and W2 to the range of 2 to 8 mm, this setting can achieve better venting effect between the two sides of the second protrusion 143, meeting the venting and pressure relief requirements of most conventional secondary batteries 100.

[0067] With the second cover plate 122 provided with the second protrusion 143, in order to further improve the support effect between the protrusion 140 and the first electrode lug 135, optionally, please refer to Figure 10In one example of the secondary battery 100 of this utility model, the protrusion 140 further includes a third protrusion 145, which is disposed in the region between the through hole 1211 and the current collector 150 extending from the second cover plate 122, i.e., the third protrusion 145 is disposed radially inside the second protrusion 143. The third protrusion 145 is a ring structure circumferentially arranged around the second cover plate 122. The third protrusion 145 can be stamped from the first cover plate 121 or it can be a solid block structure welded separately to the second cover plate 122. Preferably, in this embodiment, the third protrusion 145 is stamped from the second cover plate 122, and the liquid injection hole 1221 penetrates the third protrusion 145. At least a portion of the third protrusion 145 abuts against the current collector 150, and the current collector 150 abuts against the first electrode tab 135, so that the third protrusion 145 is indirectly supported by the first electrode tab 135. By providing the third protrusion 145, support can be provided for the first tab 135 near the center of the electrode assembly 130. Combined with the support position between the second protrusion 143 and the first tab 135, this arrangement creates two spaced support points for the first tab 135 in the radial direction of the electrode assembly 130. This effectively limits the expansion and deformation of the first tab 135 towards the opening 111, further mitigating the core-pulling phenomenon in the electrode assembly 130 and improving the safety performance of the secondary battery 100. Simultaneously, since both the second protrusion 143 and the third protrusion 145 are stamped on the second cover plate 122, the support strength and rigidity of the second cover plate 122 can be further improved.

[0068] It should be noted that, in order to improve the exhaust requirements at the support position of the third protrusion 145 and the first electrode tab 135, please refer to... Figure 10 A third vent groove 146 may also be provided on the side of the third protrusion 145 facing the electrode assembly 130, so that the gas on both sides of the third protrusion 145 can be interconnected, further improving the venting efficiency of the secondary battery 100 at the first tab 135 end.

[0069] Please see Figure 10In one example of the secondary battery 100 of this utility model, the electrode assembly 130 includes a core through hole 136. Along the radial direction of the second cover plate 122, the distance between the third protrusion 145 and the edge of the core through hole 136 is W3, and W3 is between 0.2 and 10 mm, preferably between 0.5 and 5 mm. For example, W3 can be 0.5 mm, 1.0 mm, 2.5 mm, or 5 mm, etc. It should be noted that the distance W3 between the third protrusion 145 and the edge of the core through hole 136 refers to the distance in the radial direction of the second cover plate 122 between the side of the third protrusion 145 near the core through hole 136 and the edge of the core through hole 136 near the third protrusion 145. Specifically, in this embodiment, when the injection hole 1221 penetrates the third protrusion 145, the distance W3 between the third protrusion 145 and the edge of the core through hole 136 refers to the radial distance between the edge of the injection hole 1221 and the edge of the core through hole 136. By limiting the distance W3 between the third protrusion 145 and the edge of the core through hole 136 to between 0.2 and 10 mm, this arrangement avoids the third protrusion 145 from getting too close to the core through hole 136 of the electrode assembly 130, thus preventing it from blocking the core through hole 136 and affecting the electrolyte filling efficiency of the secondary battery 100. On the other hand, it also prevents the area of ​​the second cover plate 122 extending to the through hole 1211 from becoming too large, which would lead to an excessive increase in the mass of the second cover plate 122 and affect the lightweight design of the cover plate assembly 120.

[0070] Please see Figure 11 In one example of the secondary battery 100 of this utility model, a current collector 150 is provided between the electrode assembly 130 and the cover plate assembly 120. The current collector 150 includes a body portion 151 and a thickened portion 152. The body portion 151 and the thickened portion 152 can be integrally formed or welded together, as long as an electrical connection between the body portion 151 and the thickened portion 152 can be achieved. Optionally, in this embodiment, the body portion 151 and the thickened portion 152 are integrally formed. The body portion 151 has an opening 1511 at its center. An injection hole 1221, the opening 1511, and the core through hole 136 are correspondingly provided so that when the injection hole 1221 is filled, the electrolyte can enter the interior of the core through hole 136 through the opening 1511, thereby improving the injection efficiency. The body portion 151 abuts against the first tab 135 and forms an electrical connection with it. The thickened portion 152 is located radially inside the second protrusion 143. The thickened portion 152 protrudes relative to the body portion 151 toward the cover plate assembly 120 and abuts against the second cover plate 122. The thickened portion 152 may be coaxially arranged with the body portion 151 or not. Preferably, in this embodiment, the thickened portion 152 is a ring structure coaxially arranged with the body portion 151.

[0071] It should be noted that the thickened portion 152 at least partially abuts against the area of ​​the second cover plate 122 between the through hole 1211 and the current collector 150. This arrangement facilitates welding of the second cover plate 122 and the thickened portion 152 at the through hole 1211, thereby achieving electrical connection between the second cover plate 122 and the current collector 150. By providing the thickened portion 152, with both ends abutting against the second cover plate 122 and the first electrode tab 135 respectively, indirect support is achieved between the second cover plate 122 and the first electrode tab 135. This also limits the expansion deformation of the first electrode tab 135 towards the opening 111, improving the core-pulling phenomenon of the electrode assembly 130 and enhancing the safety performance of the secondary battery 100. Simultaneously, the thickened portion 152 also improves the welding process between the second cover plate 122 and the current collector 150, increasing welding quality and efficiency.

[0072] Please see Figure 11 In one example of the secondary battery 100 of this utility model, the distance between the thickened portion 152 and the edge of the core through hole 136 along the radial direction of the second cover plate 122 is W4, and W4 is between 0.2 and 10 mm, preferably between 0.5 and 5 mm. For example, W4 can be 0.5 mm, 1.0 mm, 2.5 mm, or 5 mm, etc. It should be noted that the distance W4 between the thickened portion 152 and the edge of the core through hole 136 refers to the distance between the inner annular surface of the thickened portion 152 and the edge of the core through hole 136 near the thickened portion 152 in the radial direction of the second cover plate 122. By limiting the distance W4 between the thickened portion 152 and the edge of the core through hole 136 to between 0.2 and 10 mm, this setting can, on the one hand, prevent the thickened portion 152 from getting too close to the core through hole 136 of the electrode assembly 130, thereby reducing the obstruction of the core through hole 136 and ensuring the liquid injection efficiency of the secondary battery 100. On the other hand, it can also prevent the thickened part 152 from being too far away from the core through hole 136, thereby reducing the limiting effect of the second cover plate 122 on the expansion deformation of the first pole lug 135 toward the opening 111.

[0073] Please see Figure 12 In one embodiment of the battery pack 200 of this utility model, the battery pack 200 includes a housing 210 and at least one secondary battery 100; the housing 210 includes a first housing portion 211 and a second housing portion 212, which cover each other to form an accommodating space, in which multiple secondary batteries 100 are accommodated, and the multiple secondary batteries 100 can be connected in series and / or in parallel. The battery pack 200 can be, for example, a battery module, a battery pack, etc.

[0074] Please see Figure 13In one example of the electronic device 300 of this utility model, the electronic device 300 includes a working part 310 and a battery pack 200. The working part 310 is electrically connected to the battery pack 200 to obtain electrical power. The working part 310 can be a unit component capable of obtaining electrical power from the battery pack 200 and performing corresponding work, such as a fan blade rotation unit, a vacuum cleaner suction unit, or a wheel drive unit in an electric vehicle. The electronic device 300 can be a vehicle, mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This utility model embodiment does not impose special limitations on the above-mentioned electronic device 300. In one embodiment of the electronic device 300 of this utility model, the electronic device 300 is a vehicle, the working part 310 is the vehicle body, and the battery pack 200 is fixedly installed on the vehicle body, thereby providing driving force for the vehicle to operate.

[0075] This utility model of a secondary battery features protrusions on a first cover plate and / or a second cover plate, which are supported by a first electrode tab. This arrangement creates a support relationship between the cover plate assembly and the electrode assembly. When the electrode assembly expands and deforms, the cover plate assembly restricts the deformation of the first electrode tab, reducing the amount of deformation caused by the expansion of the first electrode tab towards the opening side. This improves the core-pulling phenomenon of the electrode assembly and reduces the probability of short circuits due to contact between the positive and negative electrodes at the first electrode tab, thereby improving the safety performance of the secondary battery. Furthermore, since the cover plate assembly includes a separate first cover plate and a second cover plate, which can be formed separately and then fixedly connected, this design allows for optimized layout of multiple local feature structures on the cover plate assembly by adjusting the connection position between the first and second cover plates, facilitating the processing and forming of local features. Therefore, the separate design of the cover plate assembly in this solution offers greater flexibility and makes it easier to install the protrusions on the first or second cover plate.

[0076] Therefore, this utility model effectively overcomes some practical problems in the prior art, thus possessing high utilization value and significance. The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit it. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A secondary battery, characterized in that, include: A housing includes a cover assembly and a sidewall with an opening at one end, the cover assembly sealing the opening; the cover assembly includes a first cover plate and a second cover plate, the first cover plate covering the opening and being sealingly connected to the sidewall; the first cover plate includes a through hole, the second cover plate at least partially obscuring the through hole, and the second cover plate being connected to the first cover plate; An electrode assembly is disposed within the housing, and the electrode assembly has a first tab on the side facing the opening; The first cover plate and / or the second cover plate include a protrusion that extends toward the electrode assembly, the protrusion being supported by the first tab.

2. The secondary battery according to claim 1, characterized in that, The protrusion includes a first protrusion disposed on the first cover plate and surrounding the first cover plate circumferentially. The radially outer side of the first protrusion includes an outer peripheral surface of the protrusion, which matches the opening.

3. The secondary battery according to claim 2, characterized in that, The side of the first protrusion facing the electrode assembly includes a first vent groove, which extends through the first protrusion.

4. The secondary battery according to claim 3, characterized in that, The first exhaust groove extends through the first protrusion in the radial direction; the depth of the first exhaust groove is T1, and T1 is in the range of 0.03 to 0.4 mm; the width of the first exhaust groove is W1, and W1 is in the range of 2 to 8 mm.

5. The secondary battery according to any one of claims 1 to 4, characterized in that, The second cover plate includes an injection hole. Along the radial direction of the first cover plate, a portion of the second cover plate extends between the first cover plate and the first electrode tab, and another portion extends between the through hole and the first electrode tab and engages with the inner wall of the through hole to form a stepped stage. The cover plate assembly also includes a sealing plate. The outer periphery of the sealing plate engages with the stepped stage and is welded to the inner wall of the through hole to seal the injection hole.

6. The secondary battery according to claim 5, characterized in that, The protrusion further includes a second protrusion disposed in the region where the second cover plate extends to the first cover plate and the first electrode tab.

7. The secondary battery according to claim 6, characterized in that, The second protrusion is arranged circumferentially around the second cover plate, and the side of the second protrusion facing the electrode assembly includes a second vent groove, which extends through the second protrusion.

8. The secondary battery according to claim 7, characterized in that, The second exhaust groove extends through the second protrusion in the radial direction; the depth of the second exhaust groove is T2, and T2 is in the range of 0.03 to 0.4 mm; the width of the second exhaust groove is W2, and W2 is in the range of 2 to 8 mm.

9. The secondary battery according to claim 6, characterized in that, The protrusion further includes a third protrusion, which is disposed in the area between the through hole and the first electrode tab of the second cover plate, and is arranged around the second cover plate in the circumferential direction.

10. The secondary battery according to claim 9, characterized in that, The electrode assembly includes a core through hole. Along the radial direction of the second cover plate, the distance between the third protrusion and the edge of the core through hole is W3, and W3 is between 0.2 and 10 mm.

11. The secondary battery according to claim 6, characterized in that, A current collecting member is provided between the electrode assembly and the cover plate assembly. The current collecting member includes a body portion and a thickened portion. The thickened portion is located radially inside the second protrusion. The thickened portion protrudes relative to the body portion toward the cover plate assembly and abuts against the second cover plate.

12. The secondary battery according to claim 11, characterized in that, The electrode assembly includes a core through hole. Along the radial direction of the second cover plate, the distance between the thickened portion and the edge of the core through hole is W4, and W4 is between 0.2 and 10 mm.

13. A battery pack, characterized in that, The secondary battery includes any one of claims 1 to 12.

14. An electronic device, characterized in that, Includes the battery pack as described in claim 13.

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