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, an electrode assembly and a current collecting component, 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, the opening is covered with the first cover plate, the first cover plate is welded to the side wall in a sealed mode, and the first cover plate comprises a through hole; the second cover plate is connected with the first cover plate and at least partially shields the through hole; the electrode assembly is accommodated in the shell, and one side, facing the opening, of the electrode assembly is provided with a first tab; the current collecting component is arranged at one end, facing the opening, of the electrode assembly and is electrically connected with the first tab; the first cover plate or the second cover plate comprises a convex part matched with the opening; the protruding portion is supported by the current collecting member on a side facing the electrode assembly, and is electrically connected to the current collecting member. According to the utility model, the technical problem that the internal resistance of the secondary battery is relatively large due to a relatively long flow guide path between the electrode assembly and the shell can be solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a battery technical field, concretely relates to a secondary battery, battery pack and electronic device. BACKGROUND

[0002] At present, secondary batteries are more and more favored by major automobile manufacturers due to their high safety, long service life, excellent fast charging performance, excellent battery consistency and low production cost.

[0003] At present, the shell of the secondary battery is generally electrified, so that the shell itself is used as one of the positive and negative electrodes when the secondary battery is grouped. The electrical connection between the electrode assembly in the shell and the shell is usually as follows: the electrode assembly is connected with the current collecting member on the opening side of the shell, the current collecting member is welded with the cover plate on the opening side, the outer periphery of the cover plate is welded with the side wall of the shell, and then the shell is electrified. In the conventional structure of the secondary battery, the current conducting path between the electrode assembly and the shell is long, and the long current path increases the internal resistance of the secondary battery, which causes more heat to be generated in the secondary battery during charging and discharging, affecting the thermal stability and safety of the secondary battery. SUMMARY

[0004] The utility model provides a kind of secondary battery, battery pack and electronic device to improve the technical problem that the current conducting path between electrode assembly and shell is long, and the internal resistance of secondary battery is large.

[0005] To achieve the above object and other related purposes, the utility model provides a kind of secondary battery, the secondary battery includes shell, electrode assembly and current collecting member, the shell includes cover plate assembly and the side wall of one end opening, and the cover plate assembly seals opening;Cover plate assembly includes first cover plate and second cover plate, first cover plate covers and is sealed with the side wall welding in opening, and first cover plate includes through-hole;Second cover plate is connected with first cover plate, and at least part of through-hole is shielded;Electrode assembly is contained in shell, and the side of electrode assembly towards opening has first tab;Current collecting member is set to the end of electrode assembly towards opening, and is electrically connected with first tab;Wherein, first cover plate or second cover plate includes the convex part matched with opening, and the convex part is protruding to electrode assembly side and is set along the circumferential direction of opening;The side of convex part towards electrode assembly is supported in current collecting member, and is electrically connected with current collecting member.

[0006] In the secondary battery example of the utility model, the second cover plate includes injection hole, and the second cover plate at least partially extends between the through-hole and the current collecting member, and cooperates with the inner wall of the through-hole to form a platform stage;Cover plate assembly further includes sealing plate, and the outer periphery of sealing plate cooperates with platform stage and is welded with the inner wall of through-hole to seal injection hole.

[0007] In the secondary battery example of the utility model, the diameter of the sealing plate is D1, the outer diameter of the shell is D, and 0.2D≤D1≤0.95D.

[0008] In the secondary battery example of the utility model, the side of the first cover plate away from the electrode assembly comprises a first reference surface, the surface of the first cover plate on the side away from the electrode assembly is not protruded from the first reference surface, and the surface of the sealing plate on the side away from the electrode assembly is flush with the first reference surface.

[0009] In the secondary battery example of the utility model, the area of the plurality of hollowed-out areas is S1, the cross section of the shell is S, and 0.2S≤S1≤0.9S.

[0010] In the secondary battery example of the utility model, the area of the plurality of hollowed-out areas is S1, the cross section of the shell is S, and 0.2S≤S1≤0.9S.

[0011] In the secondary battery example of the utility model, the convex portion is arranged on the outer periphery of the first cover plate, the radially inner side of the convex portion comprises a convex portion inner peripheral surface, and the convex portion inner peripheral surface surrounds to form the through hole; the outer periphery of the second cover plate comprises a first bending portion, the first bending portion at least partially extends between the convex portion and the current collecting member, and is welded with the convex portion and the current collecting member.

[0012] In the secondary battery example of the utility model, the convex portion is arranged on the outer periphery of the second cover plate and is welded with the current collecting member; the side of the convex portion away from the electrode assembly is formed with a recess, the first cover plate covers the recess, and the first cover plate is a flat plate structure.

[0013] In the secondary battery example of the utility model, the radially outer side of the convex portion comprises a convex portion outer peripheral surface, and the convex portion outer peripheral surface is in interference fit with the inner wall of the side wall.

[0014] In the secondary battery example of the utility model, along the radial direction of the second cover plate, the side of the convex portion close to the side wall comprises an outer ring wall, and the wall thickness of the outer ring wall is within the range of 0.2-0.8mm.

[0015] In the secondary battery example of the utility model, the radially outer side of the convex portion comprises a convex portion outer peripheral surface, and the convex portion outer peripheral surface is arranged opposite to the inner wall of the side wall, the outer periphery of the current collecting member comprises a second bending portion bent towards the side of the first cover plate, and the second bending portion is clamped between the convex portion outer peripheral surface and the side wall.

[0016] In the secondary battery example of the utility model, the second bending portion is in interference fit with the inner wall of the side wall.

[0017] In the secondary battery example of the utility model, along the radial direction of the second cover plate, the side of the convex portion close to the side wall comprises an outer ring wall; along the thickness direction of the first cover plate, the second bending portion and / or the outer ring wall abut against the first cover plate.

[0018] The utility model also provides a battery pack, the battery pack includes the secondary battery of any one of above.

[0019] The utility model also provides an electronic device, the electronic device includes the battery pack of above.

[0020] The utility model discloses a secondary battery, through setting up the convex part matched with the opening of the shell on the cover plate subassembly, and make the convex part support to the current collection member with the electrode subassembly one side, and with the current collection member electricity is connected, like this can make the electric connection position of cover plate subassembly and current collection member close to the lateral wall of shell set up, thereby can shorten the current collection member and the flow path between shell, relative to the center area of cover plate subassembly and current collection member electricity is connected structure, under the condition that the electric connection position of current collection member and first tab is same, this scheme can shorten the current collection member and the flow path between shell, thereby can reduce the internal resistance of secondary battery, reduce the heat generated in the process of secondary battery charge and discharge, improve the thermal stability and safety of secondary battery. Meanwhile, the setting of convex part can also play the positioning effect to the installation of cover plate subassembly at the opening, improve the assembly precision and assembly efficiency between cover plate subassembly and shell. In addition, the setting of convex part, when the radial welding of lateral wall and first cover plate is carried out, can shield the welding laser, thereby can reduce the damage of welding laser to other parts in the shell. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description, obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other embodiments can also be obtained according to these drawings without creating labor.

[0022] Figure 1 It is the overall structure sectional view of the secondary battery of the utility model one example;

[0023] Figure 2 It is the overall structure sectional view of the secondary battery of the utility model one example; Figure 1 It is the local enlarged view of area A;

[0024] Figure 3 It is the electrode subassembly structure schematic view of the secondary battery of the utility model one example;

[0025] Figure 4 It is the local structure schematic view of the second cover plate of the secondary battery one example in the utility model and is provided with the hollow area;

[0026] Figure 5 It is the plan view after removing the sealing plate in the secondary battery one example of the utility model;

[0027] Figure 6 For Figure 5 a sectional view in the B-B direction;

[0028] Figure 7 a partial structure schematic view of the convex part provided on the second cover plate in one example of the secondary battery of the utility model;

[0029] Figure 8 a top view of the connection between the first cover plate and the second cover plate in one example of the secondary battery of the utility model;

[0030] Figure 9 For Figure 8 a sectional view in the C-C direction;

[0031] Figure 10 a structure schematic view of the current collecting member provided with the second bending part in one example of the secondary battery of the utility model;

[0032] Figure 11 a schematic view of one example of the battery pack of the utility model;

[0033] Figure 12 a schematic view of one example of the electronic device of the utility model.

[0034] Element number explanation

[0035] 100, secondary battery; 110, shell; 111, side wall; 1111, first welding mark; 112, opening; 113, end wall; 120, cover plate assembly; 121 / 121', first cover plate; 1211, through hole; 1212, first reference surface; 122 / 122', second cover plate; 1221, liquid injection hole; 1222, hollow area; 1223, first bending part; 1224, cover part; 123, sealing plate; 1231, second welding mark; 124, stage; 130, electrode assembly; 131, positive plate; 1311, positive current collector; 1312, first coating area; 1313, first non-coating area; 132, separator; 133, negative plate; 1331, negative current collector; 1332, second coating area; 1333, second non-coating area; 134, first tab; 135, second tab; 140 / 140', current collecting member; 141, second bending part; 142, current collecting body; 150 / 150', convex part; 151, inner circumferential surface of convex part; 152, outer circumferential surface of convex part; 153, outer ring wall; 154, concave part; 160, electrode terminal; 200, battery pack; 210, box body; 211, first box body part; 212, second box body part; 300, electronic device; 310, working part. DETAILED DESCRIPTION

[0036] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure. The present application can also be implemented or applied through different specific embodiments, and various modifications or changes can be made based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. It should also be understood that the terms used in the embodiments of the present application are for describing specific specific embodiments, and are not intended to limit the protection scope of the present application. The test methods in the following embodiments are not specified, and are usually performed under conventional conditions or under conditions recommended by the manufacturer.

[0037] When the embodiments give a numerical range, it should be understood that, unless otherwise stated by the present application, each numerical range and any number between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present application are consistent with the understanding of the prior art by those skilled in the art and the description of the present application. Any method, equipment and material of the prior art similar or equivalent to the method, equipment and material described in the embodiments of the present application can be used to realize the present application.

[0038] It should be understood that the terms such as "up", "down", "left", "right", "middle" and "one" in the specification are only for the convenience of clear description, and are not intended to limit the scope of the present application. The change or adjustment of the relative relationship is also considered as the scope of the present application without substantial change of the technical content.

[0039] Please refer to Figures 1 to 12 The present application provides a secondary battery 100, a battery pack 200 and an electronic device 300, which can reduce the internal resistance of the secondary battery 100 by shortening the flow path between the electrode assembly 130 and the shell 110, thereby reducing the heat generated during the charging and discharging process of the secondary battery 100, and improving the thermal stability and safety of the secondary battery 100.

[0040] In the present application, the secondary battery 100 can include lithium ion battery, lithium-sulfur battery, sodium lithium ion battery, sodium ion battery or magnesium ion battery, etc. The embodiments of the present application are not limited to this. The secondary battery 100 can be in the shape of a cylinder, a flat body, a cuboid or other shapes, etc. The embodiments of the present application are not limited to this.

[0041] Please refer to Figure 1 Further describe the structure of the secondary battery 100, which comprises a shell 110, an electrode assembly 130 and a current collecting member 140.

[0042] The housing 110 has a mounting cavity formed therein for mounting the electrode assembly 130, electrolyte (not shown), and other components. Specifically, the housing 110 can be sized according to the specific dimensions of the electrode assembly 130, such as a diameter of 46 mm and a height of 80 mm, 95 mm, 120 mm, etc. The housing 110 can be of various shapes, such as a cylinder, a prism, etc. The housing 110 can also be of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent rusting of the housing 110 over long-term use, the housing 110 can also be plated with a rust-resistant material, such as metallic nickel, etc.

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

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

[0045] Referring to Figure 3 The positive electrode tab 131 includes a positive electrode current collector 1311 and a positive electrode active material layer coated on the positive electrode current collector 1311. The positive electrode current collector 1311 has a first coated region 1312 coated with the positive electrode active material layer and a first uncoated region 1313 not coated with the positive electrode active material layer formed thereon. The first coated region 1312 and the first uncoated region 1313 are arranged axially along the housing 110, and the first uncoated region 1313 extends to the outside of the separator 132 toward one end in the height direction of the secondary battery 100 and is bent toward the axis of the housing 110 to form a stacked positive electrode tab.

[0046] Please continue to refer to Figure 3The negative electrode sheet 133 includes a negative current collector 1331 and a negative active material layer coated on the negative current collector 1331, and a second coated area 1332 coated with the negative active material layer and a second uncoated area 1333 not coated 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 axially along the shell 110, the second uncoated area 1333 extends to the outside of the diaphragm 132 towards the other end of the height direction of the secondary battery 100, and is bent towards the axis of the shell 110 to form a stacked negative tab.

[0047] Please continue to refer to Figure 3 The diaphragm 132 is arranged between the positive electrode sheet 131 and the negative electrode sheet 133 to separate the positive active material layer and the negative active material layer. Taking the lithium ion secondary battery 100 as an example, the material of the positive current collector 1311 can be aluminum, the positive active material layer includes a positive active material, and the positive active material can be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate, etc. The material of the negative current collector 1331 can be copper, the negative active material layer includes a negative active material, and the negative active material can be carbon or silicon, etc. The base material of the diaphragm 132 can be polypropylene (PP) or polyethylene (PE), etc. In order to protect and insulate the electrode assembly 130, an insulating film can also be wrapped outside the electrode assembly 130, and the insulating film can be synthesized by PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC) or other high molecular polymer materials.

[0048] Please continue to refer to Figures 1 to 3 In an example of the secondary battery 100 of the utility model, the electrode assembly 130 is sealingly installed in the shell 110. The electrode assembly 130 is provided with a first tab 134 and a second tab 135 at both ends in the height direction of the secondary battery 100, and the polarities of the first tab 134 and the second tab 135 are opposite, wherein the first tab 134 faces the opening 112 of the shell 110, and the first tab 134 is a negative tab. It should be noted that in other embodiments, the first tab 134 can also be a positive tab, and the second tab 135 is a negative tab.

[0049] Please refer to Figure 1In the secondary battery 100 example of the utility model, the end wall 113 of the shell 110 is provided with a through terminal mounting hole, and the electrode terminal 160 is sealingly and insulatingly sleeved in the terminal mounting hole, as long as the sealing insulation between the electrode terminal 160 and the end wall 113 can be realized, the mounting mode of the electrode terminal 160 on the end wall 113 is not limited. The side of the electrode assembly 130 towards the end wall 113 is provided with a second lug 135, and one end of the electrode terminal 160 can be directly welded with the second lug 135 or can be electrically connected with the second lug 135 through the current collecting member 140, and no specific limitation is made to this.

[0050] Please refer to Figure 1 and Figure 2 The cover plate assembly 120 comprises a first cover plate 121 and a second cover plate 122. The first cover plate 121 covers the opening 112, and the outer edge of the first cover plate 121 is sealingly welded with the side wall 111 of the shell 110 and forms a first welding mark 1111. The first cover plate 121 comprises a through hole 1211, which can be located in the central region of the first cover plate 121 or can be offset from the central region. The shape of the through hole 1211 can also be various, such as a square hole, a round hole or other special-shaped holes, etc. Preferably, in order to facilitate the machining and positioning of the through hole 1211 on the first cover plate 121, in the 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 refer to Figure 2 The second cover plate 122 is arranged on the side of the first cover plate 121 towards the electrode assembly 130, and the second cover plate 122 at least partially covers the through hole 1211. The second cover plate 122 is connected with the first cover plate 121, and the connection mode can be welding connection, riveting connection or any other mode capable of realizing the electrical connection between the first cover plate 121 and the second cover plate 122.

[0052] Please refer to Figure 2 Preferably, in the embodiment, the first cover plate 121 and the second cover plate 122 are welded. The second cover plate 122 can be a disc shape matched with the through hole 1211, or can be other shapes capable of at least partially covering the through hole 1211, such as a rectangular plate, a polygonal plate, etc. Preferably, in the embodiment, the second cover plate 122 is a disc-like structure, and is coaxially arranged with the through hole 1211. In this way, the positioning and installation between the second cover plate 122 and the first cover plate 121 can be facilitated, which is beneficial to improving the assembly efficiency between the second cover plate 122 and the first cover plate 121.

[0053] Please refer to Figure 2The current collecting member 140 is arranged in the housing 110 and located at the side of the electrode assembly 130 facing the opening 112. The current collecting member 140 is electrically connected with the first tab 134. The electric connection can be achieved by conductive adhesive bonding, welding or other ways. In the embodiment, the current collecting member 140 is welded with the first tab 134 to achieve the electric connection. The specific position and welding area of the welding between the current collecting member 140 and the first tab 134 are not limited as long as the stable electric connection between the current collecting member 140 and the first tab 134 is achieved.

[0054] In an embodiment, referring to Figure 5 The first cover plate 121 can include a protrusion 150 matching the opening 112. The protrusion 150 protrudes towards the side of the electrode assembly 130 and is arranged along the circumferential direction of the opening 112. The protrusion 150 can be formed by stamping the first cover plate 121 or be a separate block structure welded to the first cover plate 121. In the embodiment, the protrusion 150 is formed by stamping the first cover plate 121. This arrangement does not increase the mass of the first cover plate 121 and can improve the support strength of the first cover plate 121 at the protrusion 150. In another embodiment, referring to Figure 7 The second cover plate 122 can also include a protrusion 150 matching the opening 112, which is formed by stamping the second cover plate 122.

[0055] Referring to Figure 2 The radial outer side of the protrusion 150 includes a protrusion outer circumferential surface 152 matching the shape of the opening 112 and arranged opposite to the inner wall of the side wall 111 to form an abutting relationship with the inner wall of the side wall 111 in the circumferential direction. The side of the protrusion 150 facing the electrode assembly 130 is supported on the current collecting member 140 and electrically connected with the current collecting member 140. The protrusion 150 can be electrically connected with the current collecting member 140 by welding or conductive adhesive. In the embodiment, the protrusion 150 is electrically connected with the current collecting member 140 by welding.

[0056] By setting the protrusion 150 on the cover plate assembly 120 matching the opening 112 of the shell 110, and supporting the protrusion 150 on the current collecting member 140 towards one side of the electrode assembly 130 and electrically connecting with the current collecting member 140, the electrical connection position of the cover plate assembly 120 and the current collecting member 140 can be arranged close to the side wall 111 of the shell 110, so as to shorten the current conducting path between the current collecting member 140 and the shell 110, compared with the structure that the cover plate assembly 120 is electrically connected with the current collecting member 140 in the central region, under the condition that the electrical connection position of the current collecting member 140 and the first tab 134 is the same, the present application can shorten the current conducting path between the electrode assembly 130 and the shell 110, so as to reduce the internal resistance of the secondary battery 100, reduce the heat generated during the charging and discharging process of the secondary battery 100, and improve the thermal stability and safety of the secondary battery 100. At the same time, the setting of the protrusion 150 can also play a positioning role in the installation of the cover plate assembly 120 at the opening 112, and improve the assembly precision and efficiency between the cover plate assembly 120 and the shell 110. In addition, the setting of the protrusion 150 can also shield the welding laser when the side wall 111 and the first cover plate 121 are radially welded, so as to reduce the damage of the welding laser to other parts inside the shell 110.

[0057] Please refer to Figure 2 and Figure 6 In an example of the secondary battery 100 of the present application, the second cover plate 122 comprises a liquid injection hole 1221, which can be located in the central region of the second cover plate 122, or in the region deviating from the center of the second cover plate 122, so as to meet the liquid injection requirement of the electrode assembly 130. Optionally, in the present embodiment, the liquid injection hole 1221 is arranged in the central region of the second cover plate 122 and coaxially arranged with the second cover plate 122. The secondary battery 100 further comprises a sealing plate 123 arranged on the side of the second cover plate 122 away from the current collecting member 140, and the sealing plate 123 covers the liquid injection hole 1221. In the radial direction of the first cover plate 121, part of the second cover plate 122 extends between the through hole 1211 and the current collecting member 140, and at least partially blocks one end of the through hole 1211 towards the electrode assembly 130, so that the second cover plate 122 cooperates with the inner wall of the through hole 1211 to form a stepped portion 124. The outer periphery of the sealing plate 123 is accommodated in the stepped portion 124 and cooperates with the stepped portion 124. The outer periphery of the sealing plate 123 is in abutment with the inner wall of the through hole 1211 to form an abutment seam arranged circumferentially around the through hole 1211, and the abutment seam position forms a second welding mark 1231, and the sealing plate 123 is welded with the inner wall of the through hole 1211 through the second welding mark 1231, so as to seal the liquid injection hole 1221.

[0058] Since the platform stage 124 is formed by the position cooperation between the second cover plate 122 and the through hole 1211, the sealing plate 123 is installed in the platform stage 124, the cooperation installation of the sealing plate 123 on the cover plate assembly 120 is realized, and therefore, the platform stage 124 does not need to be integrally punched and formed on the first cover plate 121 or the second cover plate 122, the forming precision of the platform stage 124 can be improved, the cooperation precision between the sealing plate 123 and the platform stage 124 can be further improved, and finally, the welding quality between the sealing plate 123 and the platform stage 124 is improved, and the sealing performance of the sealing plate 123 on the injection hole 1221 is ensured.

[0059] In view of the fact that a larger diameter of the sealing plate 123 can provide a larger heat conduction area, which is helpful for heat dissipation of the secondary battery 100 in the charging and discharging process, in an example of the secondary battery 100 of the utility model, please refer to Figure 2 , the diameter of the sealing plate 123 is set as D1, the outer diameter of the shell 110 is D, and 0.2D≤D1≤0.95D. Preferably, 0.5D≤D1≤0.9D. In this way, not only can a larger area of the sealing plate 123 be obtained on the side of the cover plate assembly 120 of the secondary battery 100, which is conducive to heat dissipation on the side of the cover plate assembly 120 of the secondary battery 100, and further improves the safety of the secondary battery 100 in the charging and discharging process, but also because the diameter of the sealing plate 123 is larger, the diameter of the injection hole 1221 on the second cover plate 122 can be increased to realize large-hole injection and improve the injection efficiency of the secondary battery 100. Moreover, it can also ensure that the diameter of the sealing plate 123 is not too large to reduce the probability of interference between the welding position of the sealing plate 123 and the convex part 150 and the current collecting member 140.

[0060] In order to further improve the heat dissipation effect on the side of the cover plate assembly 120 of the secondary battery 100, optionally, please refer to Figure 2 In an example of the secondary battery 100 of the utility model, the side of the first cover plate 121 away from the electrode assembly 130 comprises a first reference surface 1212, and the surface of the first cover plate 121 on the side away from the electrode assembly 130 is not protruded from the first reference surface 1212. When the secondary battery 100 is installed in groups, the secondary battery 100 on the side of the cover plate assembly 120 is in contact with the external cooling assembly through the first reference surface 1212 to exchange heat. The first reference surface 1212 can be an overall planar structure on the side of the first cover plate 121 away from the electrode assembly 130, or a plurality of annular surface structures arranged at intervals. The surface of the sealing plate 123 on the side away from the electrode assembly 130 is flush with the first reference surface 1212. In this way, the planar area of the secondary battery 100 in contact with the external cooling assembly on the side of the cover plate assembly 120 can be increased, and therefore, the heat dissipation efficiency of the secondary battery 100 can be improved, and the safety performance of the secondary battery 100 is further improved.

[0061] In order to facilitate the welding between the cover plate assembly 120 and the shell 110, and the welding between the current collecting member 140 and the first tab 134 after the welding, optionally, please refer to Figure 4 and Figure 5 In an example of the secondary battery 100 of the utility model, the area of the second cover plate 122 exposed to the through hole 1211 includes a plurality of hollow areas 1222, and the current collecting member 140 is at least partially exposed to the hollow areas 1222. The shape of the hollow area 1222 can be a round hole structure, a fan-shaped structure, an oval structure, etc. There are at least two hollow areas 1222 along the circumferential direction of the second cover plate. Preferably, in the embodiment, as shown in Figure 5 The hollow area 1222 is a fan-shaped structure, and the hollow area 1222 is provided with four hollow areas 1222 arranged along the axis of the second cover plate 122. By at least partially exposing the current collecting member 140 to the hollow area 1222, the welding between the current collecting member 140 and the first tab 134 can be performed through the hollow area 1222 after the welding between the cover plate assembly 120 and the side wall 111 of the shell 110. Thus, the first cover plate 121, the second cover plate 122 and the current collecting member 140 can be welded together before entering the shell, and then when the opening 112 is closed, only the welding between the first cover plate 121 and the side wall 111 is needed to complete the electrical connection between the cover plate assembly 120 and the current collecting member 140 and the side wall 111, thereby improving the assembly efficiency of the secondary battery 100. At the same time, since the first cover plate 121, the second cover plate 122 and the current collecting member 140 are welded before entering the shell, the welding process can be more flexible, which is beneficial to improve the welding efficiency and welding quality.

[0062] In order to ensure that the welding area between the current collecting member 140 and the first tab 134 can better meet the connection strength and current conducting requirements between the current collecting member 140 and the electrode assembly 130, optionally, please refer to Figure 4 and Figure 5In the secondary battery 100 example of the utility model, the sum of the areas of the plurality of hollow areas 1222 opened on the second cover plate 122 is S1, that is, the area of the current collecting member 140 exposed to the hollow area 1222 is also S1. The cross section of the shell 110 is S, and 0.2S≤S1≤0.9S. Preferably, 0.3S≤S1≤0.7S. It should be noted that the cross section S of the shell 110 specifically refers to the cross section area of the mounting cavity formed in the shell 110. By making 0.3S≤S1≤0.7S, such setting, not only can the current collecting member 140 and the first tab 134 obtain a better welding area to meet the flow requirements of most conventional secondary batteries 100 on the opening 112 side. Moreover, it can also avoid the probability of insufficient support strength of the second cover plate 122 due to the area of the hollow area 1222 being too large, so as to ensure the support connection strength between the second cover plate 122 and the sealing plate 123.

[0063] Please refer to Figure 2 and Figure 4 In the secondary battery 100 example of the utility model, the convex part 150 is arranged on the outer periphery of the first cover plate 121, that is, the convex part 150 is formed on the outer periphery of the first cover plate 121. The radially inner side of the convex part 150 includes a convex inner circumferential surface 151, and the convex inner circumferential surface 151 surrounds to form a through hole 1211. The second cover plate 122 includes a cover body part 1224 and a first bending part 1223, and the first bending part 1223 is arranged around the outer periphery of the cover body part 1224. Along the radial direction of the second cover plate 122, one side of the first bending part 1223 is connected with the outer periphery of the cover body part 1224, and the other side of the first bending part 1223 at least partially extends between the convex part 150 and the current collecting member 140, and is welded with the convex part 150 and the current collecting member 140. The first bending part 1223 can be integrally stamped and formed with the cover body part 1224, or can be welded. The part of the first bending part 1223 extending between the current collecting member 140 and the first cover plate 121 can be an integral annular structure, or can be a plurality of locally arranged block structures. Preferably, in the embodiment, the first bending part 1223 is integrally stamped and formed with the cover body part 1224, and the part of the first bending part 1223 extending between the current collecting member 140 and the first cover plate 121 is an integral annular structure. Such setting facilitates the circumferential welding positioning between the convex part 150, the current collecting member 140 and the second cover plate 122. The side of the cover body part 1224 away from the first bending part 1223 extends between the through hole 1211 and the current collecting member 140, and at least partially blocks the side of the through hole 1211 facing the electrode assembly 130, to form the above-mentioned stepped stage 124, as shown in Figure 6 The center area of the cover body part 1224 is provided with a liquid injection hole 1221, and the liquid injection hole 1221 is coaxially arranged with the cover body part 1224.

[0064] By setting the first bending portion 1223 and extending the first bending portion 1223 at least partially between the current collecting member 140 and the first cover plate 121, the welding between the first cover plate 121, the second cover plate 122 and the current collecting member 140 can be simultaneously realized when welding at the position of the convex portion 150, thereby reducing the welding procedure between the cover plate assembly 120 and the current collecting member 140 and improving the welding efficiency. Meanwhile, since the connection positions of the current collecting member 140, the first cover plate 121 and the second cover plate 122 are all arranged at the position of the convex portion 150, the current flowing through the current collecting member 140 can be sequentially transmitted to the first bending portion 1223, the convex portion 150 and the shell 110, thereby reducing the probability of the current being transmitted to the area other than the convex portion 150, and further reducing the internal resistance generated at the side of the cover plate assembly 120 of the secondary battery 100, and further improving the charge-discharge performance and safety of the secondary battery 100.

[0065] Please refer to Figures 7 to 9 In an example of the secondary battery 100, the second cover plate 122' includes a cover body portion 1224 and a convex portion 150', the convex portion 150' is arranged around the outer periphery of the cover body portion 1224, and the side of the convex portion 150' away from the side wall 111 is connected with the outer periphery of the cover body portion 1224. The side of the convex portion 150' facing the electrode assembly 130 is welded with the current collecting member 140. The convex portion 150' can be integrally stamped and formed with the cover body portion 1224, or can be welded. Optionally, in the embodiment, the convex portion 150' is integrally stamped and formed with the cover body portion 1224. The side of the convex portion 150' away from the electrode assembly 130 is formed with a recess 154, the first cover plate 121' covers the recess 154 and is welded with the cover body portion 1224, and the first cover plate 121' is a flat plate structure, as shown in Figure 7 In this way, the overall planar structure can be formed on the side of the first cover plate 121' away from the electrode assembly 130, the planar area coplanar with the first reference surface 1212 is increased, the contact area of the secondary battery 100 at the side of the cover plate assembly 120 with the external cooling assembly can be increased under the condition that the outer lateral surface area of the sealing plate 123 remains unchanged, and thus the heat dissipation efficiency of the secondary battery 100 can be further improved, and the safety performance of the secondary battery 100 can be improved. Meanwhile, the first cover plate 121' is arranged as a flat plate structure, which can facilitate the forming and processing of the first cover plate 121', and is conducive to reducing the production and processing cost of the first cover plate 121'.

[0066] It should be noted that, please refer to Figure 7 and Figure 9 When the convex portion 150' is arranged on the second cover plate 122', a plurality of hollow areas 1222 can also be arranged on the area of the second cover plate 122' exposed to the through hole 1211, so as to facilitate the welding between the first tab 134 and the current collecting member 140.

[0067] In order to improve the welding positioning requirement between the convex portion 150' and the current collecting member 140, optionally, please refer to Figure 7 In an example of the secondary battery 100 of the utility model, the convex portion outer peripheral surface 152 is in interference fit with the inner wall of the side wall 111. In this way, the probability of a gap existing between the convex portion outer peripheral surface 152 and the inner wall of the side wall 111 can be reduced, so that the shielding effect of the convex portion 150' on the welding laser can be improved, and the probability of the welding laser damaging the components inside the shell 110 can be further reduced. At the same time, since the convex portion outer peripheral surface 152 is in interference fit with the inner wall of the side wall 111, the friction between the convex portion outer peripheral surface 152 and the inner wall of the side wall 111 can be increased, so as to reduce the probability of the convex portion 150' being axially displaced inside the shell 110, so that the supporting effect of the convex portion 150' on the current collecting member 140 can be improved, and the supporting strength of the current collecting member 140 on the first tab 134 can be further improved, so as to reduce the probability of the electrode assembly 130 being drawn out on the side of the first tab 134, and the safety performance of the secondary battery 100 can be improved.

[0068] Please refer to Figure 7 In an example of the secondary battery 100 of the utility model, along the radial direction of the second cover plate 122', the side of the convex portion 150' close to the side wall 111 includes an outer ring wall 153, the outer ring wall 153 extends from the side of the electrode assembly 130 towards the side of the first cover plate 121', and the outer ring wall 153 abuts against the inner wall of the side wall 111. The wall thickness of the outer ring wall 153 is T, and the wall thickness T is within the range of 0.2-0.8 mm, preferably, the wall thickness T is within the range of 0.4-0.6 mm, for example, T can be 0.4 mm, 0.5 mm or 0.6 mm, etc. By setting the wall thickness T of the outer ring wall 153 within the range of 0.4-0.6 mm, not only can the probability of the outer ring wall 153 being welded through by the laser be reduced, but also the shielding effect of the outer ring wall 153 on the welding laser can be ensured; and within this thickness range, the current collecting member 140 and the shell 110 can also obtain a better flow resistance, so as to further ensure the flow performance between the current collecting member 140 and the shell 110.

[0069] Please refer to Figure 10In the secondary battery 100 example of the utility model, the convex portion outer circumferential surface 152 is opposite to the inner wall of the side wall 111, the current collecting member 140' includes the current collecting body 142 and the second bending portion 141, the second bending portion 141 is around the outer circumferential surface of the current collecting body 142. One end of the second bending portion 141 is connected with the outer circumferential edge of the current collecting body 142, the other end of the second bending portion 141 is bent from the electrode assembly 130 side to the first cover plate 121' side, and the second bending portion 141 is clamped between the convex portion outer circumferential surface 152 and the inner wall of the side wall 111. The second bending portion 141 can be a ring structure, or a plurality of locally arranged sheet structures. Optionally, in the embodiment, the second bending portion 141 is a ring structure coaxially arranged with the current collecting body 142. The second bending portion 141 can be welded to the side wall 111 and the convex portion outer circumferential surface 152, or not welded, as long as it can ensure the conductive connection between the convex portion 150' and the second bending portion 141 and the side wall 111. By arranging the second bending portion 141 and clamping the second bending portion 141 between the convex portion outer circumferential surface 152 and the inner wall of the side wall 111, an electric current conduction path is formed between the convex portion 150', the second bending portion 141 and the side wall 111, so that the current flowing through the current collecting member 140' can be directly conducted to the shell 110 from the second bending portion 141 when passing through the convex portion 150', without flowing through the first cover plate 121' above the convex portion 150', thereby further shortening the current conduction path between the current collecting member 140 and the shell 110.

[0070] To further improve the stability of the electrical connection between the second bending portion 141 and the side wall 111 and the current collecting member 140', optionally, in the secondary battery 100 example of the utility model, the second bending portion 141 is in interference fit with the inner wall of the side wall 111. This arrangement can further reduce the probability of gaps between the second bending portion 141 and the side wall 111, and between the second bending portion 141 and the convex portion outer circumferential surface 152, so that the convex portion outer circumferential surface 152, the second bending portion 141 and the side wall 111 are more tightly fitted, which not only helps to improve the stability of current conduction, but also increases the friction between the second bending portion 141 and the side wall 111, reduces the probability of axial displacement of the convex portion 150' inside the shell 110, improves the support of the convex portion 150' on the first tab 134, and reduces the probability of core extraction of the electrode assembly 130 on the first tab 134.

[0071] Considering the stability of current conduction between the current collecting member 140 and the shell 110, optionally, refer to Figure 10In the secondary battery 100 example, along the thickness direction of the first cover plate 121', the one end of the second bending part 141 away from the electrode assembly 130 abuts against the side surface of the first cover plate 121' facing the electrode assembly 130. The one end of the second bending part 141 away from the electrode assembly 130 can partially abut against the first cover plate 121', or can fully abut against the first cover plate 121'. Preferably, in the embodiment, the one end of the second bending part 141 away from the electrode assembly 130 fully abuts against the first cover plate 121' along the circumferential direction of the first cover plate 121'. In this way, along the circumferential direction of the first cover plate 121', the second bending part 141 can obtain a relatively uniform abutting force. By making the one end of the second bending part 141 away from the electrode assembly 130 abut against the side surface of the first cover plate 121' facing the electrode assembly 130, on the one hand, the first cover plate 121' can produce a better axial positioning effect on the current collecting member 140, increase the support effect of the current collecting member 140 on the first tab 134, reduce the amount of swelling deformation of the first tab 134 toward the opening 112 side, and further improve the safety performance of the secondary battery 100. On the other hand, an additional flow path can be formed between the second bending part 141, the first cover plate 121' and the shell 110, so as to improve the unstable current transmission phenomenon caused by the gap between the second bending part 141, the convex outer peripheral surface 152 and the side wall 111, and improve the electrical connection stability of the secondary battery 100.

[0072] In another embodiment, please refer to Figure 10 In another embodiment, please refer to

[0073] In other embodiments, the end surface of the outer ring wall 153 and the end surface of the second bending part 141 can both abut against the side surface of the first cover plate 121' facing the electrode assembly 130. In this way, the beneficial effects in the above embodiments can also be achieved.

[0074] Please refer toFigure 11 In an embodiment of the battery pack 200, the battery pack 200 comprises a box body 210 and at least one secondary battery 100; the box body 210 comprises a first box body part 211 and a second box body part 212, the first box body part 211 and the second box body part 212 are mutually covered to form an accommodating space, a plurality of secondary batteries 100 are accommodated in the accommodating space, and the plurality of secondary batteries 100 can be connected in series and / or in parallel. The battery pack 200 may, for example, be a battery module, a battery pack, etc.

[0075] Please refer to Figure 12 In an example of the electronic device 300, the electronic device 300 comprises a working part 310 and a battery pack 200, and the working part 310 is electrically connected to the battery pack 200 to obtain power support. The working part 310 can be a unit component capable of obtaining the power of the battery pack 200 and making corresponding work, such as a fan blade rotating unit, a dust suction working unit of a dust collector, a wheel driving unit in an electric vehicle, etc. The electronic device 300 can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, and an electric tool, etc. The vehicle can be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile, or a range extended automobile, etc.; the spacecraft comprises an airplane, a rocket, a space shuttle, and a spacecraft, etc.; the electric toy comprises a fixed or mobile electric toy, such as a game machine, an electric automobile toy, an electric ship toy, and an electric airplane toy, etc.; the electric tool comprises a metal cutting electric tool, a grinding electric tool, an assembling electric tool, and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator, and an electric planer, etc. The electronic device 300 is not specially limited in the embodiments of the present application. In an embodiment of the electronic device 300, the electronic device 300 is a vehicle, the working part 310 is a vehicle body of the vehicle, and the battery pack 200 is fixedly installed on the vehicle body, thereby providing driving force for the vehicle to realize the running of the vehicle.

[0076] The utility model discloses secondary battery passes through setting the convex part with the opening of casing matching on the cover plate subassembly, and make the convex part support to the current collection member with the electrode subassembly one side, and with the current collection member electricity is connected, like this can make the electric connection position of cover plate subassembly and current collection member close the lateral wall setting of casing, thereby can shorten the current collection member and the flow path between casing, relative to the structure that the center area of cover plate subassembly and current collection member electricity is connected, under the condition that the electric connection position of current collection member and first tab is same, this scheme can shorten the current collection member and the flow path between casing, thereby can reduce the internal resistance of secondary battery, reduce the heat that secondary battery generates in the process of charge and discharge, improve the thermal stability and security of secondary battery. Meanwhile, the setting of convex part can also position effect to the installation of cover plate subassembly at the opening, improve the assembly precision and assembly efficiency between cover plate subassembly and casing. In addition, the setting of convex part, when radial welding is carried out to the lateral wall and first cover plate, can shield the effect of welding laser, thereby can reduce the damage of welding laser to other parts in the casing.

[0077] Therefore, the utility model effectively overcomes some practical problems in the prior art, thereby having high utilization value and use significance. The above examples only exemplarily illustrate the principle and effect of the utility model, and are not used to limit the utility model. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the utility model. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the utility model should be covered by the claims of the utility model.

Claims

1. A secondary battery characterized by comprising: The application relates to a battery shell. The shell comprises a cover plate assembly and a side wall with an open end, the cover plate assembly seals the open end; the cover plate assembly comprises a first cover plate and a second cover plate, the first cover plate covers the open end and is sealedly welded with the side wall, the first cover plate comprises a through hole; the second cover plate is connected with the first cover plate and at least partially covers the through hole; An electrode assembly is arranged in the shell, and the electrode assembly has a first tab on a side facing the open end; A current collecting member is arranged on one end of the electrode assembly facing the open end and is electrically connected with the first tab; The first cover plate or the second cover plate comprises a convex part matched with the open end, the convex part is arranged on the side of the electrode assembly and surrounds the open end in the circumferential direction; the side of the convex part facing the electrode assembly is supported on the current collecting member and is electrically connected with the current collecting member.

2. The secondary battery according to claim 1, characterized by The second cover plate comprises a liquid injection hole, the second cover plate at least partially extends between the through hole and the current collecting member and cooperates with the inner wall of the through hole to form a platform stage; the cover plate assembly further comprises a sealing plate, the outer periphery of the sealing plate cooperates with the platform stage and is welded with the inner wall of the through hole to seal the liquid injection hole.

3. The secondary battery according to claim 2, characterized by The diameter of the sealing plate is D1, the outer diameter of the shell is D, and 0.2D<=D1<=0.95D.

4. The secondary battery according to claim 2, characterized by The side of the first cover plate away from the electrode assembly comprises a first reference surface, the surface of the first cover plate away from the electrode assembly is not protruded from the first reference surface, and the surface of the side of the sealing plate away from the electrode assembly is flush with the first reference surface.

5. The secondary battery according to claim 4, characterized by The area of the second cover plate exposed to the through hole comprises a plurality of hollowed-out areas, and the current collecting member is at least partially exposed to the hollowed-out areas.

6. The secondary battery according to claim 5, characterized by The sum of the areas of the plurality of hollowed-out areas is S1, the cross section of the shell is S, and 0.2S<=S1<=0.9S.

7. The secondary battery according to any one of claims 1 to 6, characterized by The convex part is arranged on the outer periphery of the first cover plate, the radially inner side of the convex part comprises a convex part inner periphery surface, and the convex part inner periphery surface surrounds the through hole; the outer periphery of the second cover plate comprises a first bending part, the first bending part at least partially extends between the convex part and the current collecting member and is welded with the convex part and the current collecting member.

8. The secondary battery according to any one of claims 1 to 6, characterized by The convex part is arranged on the outer periphery of the second cover plate and is welded with the current collecting member; the side of the convex part away from the electrode assembly is formed with a recess, the first cover plate covers the recess, and the first cover plate is a flat plate structure.

9. The secondary battery according to claim 8, characterized by The radially outer side of the convex part comprises a convex part outer periphery surface, and the convex part outer periphery surface is in interference fit with the inner wall of the side wall.

10. The secondary battery according to claim 9, characterized by In the radial direction of the second cover plate, the side of the convex part close to the side wall comprises an outer ring wall, and the wall thickness of the outer ring wall is within the range of 0.2-0.8 mm.

11. The secondary battery according to claim 8, characterized by The radially outer side of the convex part comprises a convex part outer periphery surface, the convex part outer periphery surface is arranged opposite to the inner wall of the side wall, the outer periphery of the current collecting member comprises a second bending part bent towards the first cover plate, and the second bending part is clamped between the convex part outer periphery surface and the side wall.

12. The secondary battery according to claim 11, characterized by The second bending part is in interference fit with the inner wall of the side wall.

13. The secondary battery according to claim 11, characterized by In a radial direction of the second cover plate, the convex portion includes an outer ring wall close to one side of the side wall; and in a thickness direction of the first cover plate, the second bent portion and / or the outer ring wall abut against the first cover plate.

14. A battery pack, characterized by A secondary battery including any one of claims 1 to 13.

15. An electronic device, comprising: A battery pack including claim 14.

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