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 an end cover, the shell comprises a side wall, and the side wall comprises an opening; the electrode assembly is arranged in the shell; the end cover seals the opening, the periphery of the end cover comprises a protruding part which is arranged in a surrounding mode and protrudes towards the electrode assembly, and the radial inner side of the protruding part comprises a protruding part inner circumferential face. Wherein the convex part supports the electrode assembly, a channel is arranged between the convex part and the electrode assembly, and the channel is communicated with an inner side area defined by the inner circumferential surface of the convex part and an area between the inner circumferential surface of the convex part and the side wall. According to the secondary battery, the channel is arranged in the abutting area of the end cover and the current collecting component, so that the discharge speed of gas in the secondary battery can be increased, and meanwhile, the liquid injection, infiltration and formation efficiency of the secondary battery can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a secondary battery, a battery pack and an electronic device. Background Art

[0002] With the development of lithium battery technology, the requirements for the energy density of battery cells are getting higher and higher, and secondary batteries have become one of the current mainstream battery cell forms because of their high assembly efficiency. The cooperation between the end cap and the shell of the secondary battery can be welded. During the welding process, in order to prevent the laser from entering the shell and damaging the internal structure of the secondary battery, a surrounding convex portion is generally provided on the periphery of the end cap to block the laser from entering the shell. The convex portion will abut against the electrode assembly or the current collecting component inside the shell, thereby affecting the circulation and diffusion speed of the gas in the secondary battery, and further affecting the pressure relief and exhaust efficiency of the secondary battery during thermal runaway, reducing the safety performance of the secondary battery. Utility Model Content

[0003] The utility model provides a secondary battery, a battery pack and an electronic device, so as to improve the pressure relief and exhaust efficiency of the secondary battery when it is in thermal runaway, and ensure the safety performance of the secondary battery.

[0004] To achieve the above-mentioned purpose and other related purposes, the utility model provides a secondary battery, including: a shell, an electrode assembly and an end cover; the shell includes a side wall, and the side wall includes an opening; the electrode assembly is arranged in the shell; the end cover seals the opening, and the outer periphery of the end cover includes a convex portion protruding toward the electrode assembly, and the radial inner side of the convex portion includes an inner circumferential surface of the convex portion; wherein the convex portion supports the electrode assembly, and a channel is provided between the convex portion and the electrode assembly, and the channel connects the inner area surrounded by the inner circumferential surface of the convex portion and the area between the inner circumferential surface of the convex portion and the side wall.

[0005] In an example of the secondary battery of the present invention, a first gap is formed between the electrode assembly and the side wall, a second gap is formed between the end cover and the electrode assembly, and a channel connects the first gap and the second gap.

[0006] In an example of the secondary battery of the present invention, the radial outer side of the protrusion includes an outer peripheral surface of the protrusion, and the channel includes a first recessed portion arranged on the surface of the protrusion facing the electrode assembly, the first recessed portion is recessed in a direction away from the electrode assembly, and extends through the inner peripheral surface of the protrusion and the outer peripheral surface of the protrusion.

[0007] In an example of the secondary battery of the present invention, the first recess extends along the radial direction of the secondary battery.

[0008] In an example of the secondary battery of the present invention, the electrode assembly has a first pole tab on one side facing the opening, and the protrusion abuts against the first pole tab.

[0009] In an example of the secondary battery of the present invention, the electrode assembly has a first pole tab on one side facing the opening, and the secondary battery further includes a current collecting member, which is at least partially clamped between the protrusion and the electrode assembly and electrically connected to the first pole tab.

[0010] In an example of the secondary battery of the present invention, the channel also includes a through hole arranged on the outer periphery of the current collecting component, an abutment area is formed between the protrusion and the current collecting component, and the through hole at least partially extends to the abutment area, and at least another part extends to the radial inner side of the protrusion.

[0011] In an example of the secondary battery of the present invention, at least part of the through holes are arranged corresponding to the first recessed portion.

[0012] In an example of the secondary battery of the present invention, the length of the through hole along the radial direction of the secondary battery is greater than or equal to 1 / 2 of the length of the abutting area along the radial direction of the secondary battery.

[0013] In an example of the secondary battery of the present invention, the through hole extends along the radial direction of the current collecting member and penetrates the outer edge of the current collecting member.

[0014] In an example of the secondary battery of the present invention, a side of the current collecting member facing the protrusion includes a thickened portion welded to the protrusion.

[0015] In an example of a secondary battery of the utility model, the thickened portion includes an inner circumferential surface of the thickened portion facing the axis of the shell and an outer circumferential surface of the thickened portion facing away from the axis of the shell; the channel also includes a second recessed portion arranged in the thickened portion, the second recessed portion is recessed toward the side away from the convex portion, and the second recessed portion extends through the inner circumferential surface of the thickened portion and the outer circumferential surface of the thickened portion.

[0016] In an example of the secondary battery of the present invention, the secondary battery further includes an explosion-proof valve, which is arranged on the end cover and located in the inner area surrounded by the inner circumference of the convex portion.

[0017] In an example of the secondary battery of the present invention, the end cover is provided with a liquid injection hole, and the liquid injection hole is located in the inner area surrounded by the inner peripheral surface of the convex part.

[0018] In an example of a secondary battery of the utility model, the end cover also includes an extension portion arranged around the outer periphery of the protrusion, the side wall located on one side of the opening includes an end face, the extension portion overlaps the end face and is fixed to the end face by welding; along the thickness direction of the end cover, the height of the protrusion protruding from the extension portion is 2.0 to 4.0 mm.

[0019] The utility model also provides a secondary battery, comprising: a shell, an electrode assembly, a current collecting component and an end cover; the shell comprises a side wall, and the side wall comprises an opening; the electrode assembly is arranged in the shell, and the side of the electrode assembly facing the opening has a first pole ear; the current collecting component is arranged on the side of the electrode assembly facing the opening, and the current collecting component is electrically connected to the first pole ear; the end cover seals the opening, and a convex portion protruding toward the electrode assembly is arranged around the outer periphery of the end cover, and the radial inner side of the convex portion includes an inner circumferential surface of the convex portion; wherein the convex portion abuts against the current collecting component, and the current collecting component is provided with a channel, and the channel connects the inner area surrounded by the inner circumferential surface of the convex portion and the area between the inner circumferential surface of the convex portion and the side wall.

[0020] In an example of the secondary battery of the present invention, the channel includes a through hole arranged on the outer periphery of the current collecting member, an abutment area is formed between the protrusion and the current collecting member, and the through hole at least partially extends to the abutment area and at least another part extends to the radial inner side of the protrusion.

[0021] In an example of the secondary battery of the present invention, the through hole is an elongated through hole extending in the radial direction of the current collecting member.

[0022] In an example of the secondary battery of the present invention, the length of the through hole along the radial direction of the secondary battery is greater than or equal to 1 / 2 of the length of the abutting area along the radial direction of the secondary battery.

[0023] In an example of the secondary battery of the present invention, the through hole extends through the outer edge of the current collecting member in a radial direction of the current collecting member.

[0024] In an example of a secondary battery of the utility model, the side of the current collecting component facing the convex portion includes a thickened portion that abuts against and is welded to the convex portion, and the thickened portion includes an inner circumferential surface of the thickened portion facing the axis of the shell and an outer circumferential surface of the thickened portion facing away from the axis of the shell; the channel includes a second recessed portion arranged in the thickened portion, and the second recessed portion is recessed toward the side away from the convex portion, and the second recessed portion extends through the inner circumferential surface of the thickened portion and the outer circumferential surface of the thickened portion.

[0025] The utility model also provides a battery pack, which includes the secondary battery in any one of the above examples.

[0026] The utility model further provides an electronic device, which includes the above-mentioned battery pack.

[0027] The utility model secondary battery, by setting a channel between the convex part and the electrode assembly, and making the channel connect the inner area surrounded by the inner circumference of the convex part and the area between the inner circumference of the convex part and the side wall, so that, on the one hand, the gas circulation between the inner area surrounded by the inner circumference of the convex part and the area between the inner circumference of the convex part and the side wall can be accelerated. When the secondary battery is thermally runaway, the gas generated in the area between the inner circumference of the convex part and the side wall can enter the inner area surrounded by the inner circumference of the convex part through the channel, and be discharged from the pressure relief position, thereby ensuring that the secondary battery can achieve directional pressure relief. At the same time, when the secondary battery is filled and vacuumed during the formation process, the gas in the area between the inner circumference of the convex part and the side wall can quickly flow into the inner area surrounded by the inner circumference of the convex part through the channel, so that the exhaust speed in the secondary battery can be accelerated, the vacuuming time can be saved, and the gas can be avoided from being retained inside the shell, ensuring the vacuuming effect, thereby ensuring the effect of filling and forming. On the other hand, when the secondary battery is filled, the setting of the channel can also accelerate the circulation speed of the electrolyte inside the shell, thereby effectively improving the filling efficiency of the secondary battery. In addition, providing a channel between the protrusion of the end cap and the electrode assembly can also reduce deformation during assembly of the end cap, and is more conducive to improving the installation accuracy between the end cap and the shell and the stability of the electrical connection between the end cap and the electrode assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a three-dimensional overall schematic diagram of an embodiment of a secondary battery of the utility model;

[0030] Figure 2 This is a cross-sectional view of the overall structure of an embodiment of a secondary battery of the utility model;

[0031] Figure 3 for Figure 2 A partial enlarged view of the middle area A;

[0032] Figure 4 for Figure 3 A partial enlarged view of a channel provided between the protrusion and the electrode assembly in the embodiment;

[0033] Figure 5 This is a schematic diagram of the overall structure of the end cover in one embodiment of the secondary battery of the utility model;

[0034] Figure 6This is a schematic diagram of a structure in which a channel is provided between a convex portion and a current collecting member in an embodiment of a secondary battery of the utility model;

[0035] Figure 7 for Figure 6 A partially enlarged schematic diagram of a channel provided between the convex portion and the current collecting member in the embodiment;

[0036] Figure 8 for Figure 6 A schematic diagram of the installation positions of the end cover and the current collecting member in the illustrated embodiment;

[0037] Fig. 9 This is a schematic diagram of the installation positions of the current collecting component and the end cover in one embodiment of the secondary battery of the utility model;

[0038] Fig.10 This is a partial structural schematic diagram of the end cover side of another embodiment of the secondary battery of the utility model;

[0039] Fig.11 for Fig.10 A schematic diagram of partial installation of the current collecting member and the protrusion in the illustrated embodiment;

[0040] Fig.12 This is a schematic diagram of the distribution of through holes on the current collecting component in one embodiment of the secondary battery of the utility model;

[0041] Fig.13 This is a schematic diagram of the distribution of through holes on the current collecting component in another embodiment of the secondary battery of the utility model;

[0042] Fig.14 A three-dimensional schematic diagram of the corresponding arrangement of the through hole and the first recess in an embodiment of the secondary battery of the utility model;

[0043] Fig.15 This is a partial structural schematic diagram of the end cover side of another embodiment of the secondary battery of the utility model;

[0044] Fig.16 for Fig.15 A partial enlarged view of the corresponding position of the through hole and the first recess in the embodiment shown;

[0045] Fig.17 This is a schematic diagram of the relative installation positions of the thickened portion and the convex portion in an embodiment of the secondary battery of the utility model;

[0046] Fig.18 for Fig.17 A partial enlarged view of the corresponding installation positions of the second concave portion and the convex portion in the embodiment shown;

[0047] Fig.19 This is a structural schematic diagram of a current collecting component provided with a thickened portion in an embodiment of a secondary battery of the utility model;

[0048] Fig. 20 A three-dimensional schematic diagram of the corresponding arrangement of the first concave portion and the second concave portion in an embodiment of the secondary battery of the utility model;

[0049] Fig.21 This is a schematic diagram of the partial structure of the end cover side of an embodiment of the secondary battery of the utility model;

[0050] Fig. 22 for Fig.21 A partial enlarged view of the corresponding positions of the first concave portion and the second concave portion in the embodiment shown;

[0051] Fig.23 This is a schematic diagram of the overall structure of an embodiment of a battery pack of the utility model;

[0052] Fig.24 This is a schematic diagram of the structure of the battery pack of the utility model installed on a vehicle.

[0053] Component number description

[0054] 100, secondary battery; 110, housing; 111, end wall; 112, side wall; 1121, end face; 113, opening; 120, electrode assembly; 121, first pole ear; 122, second pole ear; 123, stacking gap; 130, current collecting member; 131, through hole; 132, thickened portion; 1321, second recessed portion; 1322, inner circumferential surface of thickened portion; 1323, outer circumferential surface of thickened portion; 133, current collecting body; 140, end cover; 141, convex portion; 1 411. first recess; 1412. inner peripheral surface of the convex portion; 1413. outer peripheral surface of the convex portion; 142. abutment area; 143. cover body; 145. injection hole; 146. extension portion; 147. cover plate; 150. first gap; 160. second gap; 170. passage; 180. explosion-proof valve; 190. 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

[0055] The following describes the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and the 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 invention are intended to describe specific implementation schemes, rather than to limit the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are usually carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0056] When numerical ranges are given in the embodiments, it should be understood that unless otherwise specified in the present invention, both endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention are in accordance with the prior art mastery of those skilled in the art and the description of the present invention, and any prior art methods, equipment and materials similar or equivalent to the methods, equipment and materials in the embodiments of the present invention can also be used to implement the present invention.

[0057] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present utility model. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present utility model without substantially changing the technical content.

[0058] See also Figures 1 to 24 The utility model provides a secondary battery 100, a battery pack 200 and an electronic device 300. The secondary battery 100 can improve the pressure relief and exhaust efficiency of the secondary battery 100 during thermal runaway by setting a channel 170 between the protrusion 141 of the end cover 140 and the electrode assembly 120, thereby improving the safety performance of the secondary battery 100; at the same time, the setting of the channel 170 can also improve the injection efficiency inside the secondary battery 100, save the time of injection and formation of the secondary battery 100, and improve the production efficiency of the secondary battery 100.

[0059] See also Figure 1 and Figure 3, further describing the structure of the secondary battery 100, the secondary battery 100 includes: a shell 110, an electrode assembly 120 and an end cover 140. A accommodating cavity is formed in the shell 110 for accommodating the electrode assembly 120, electrolyte and other components. The shell 110 may be open at one end or at both ends. The specific size of the shell 110 may be determined according to the specific size of the electrode assembly 120, for example, to meet the specifications of 4680, 4695, 46120, etc. of the large secondary battery 100. The shell 110 may be made of a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent the shell 110 from rusting during long-term use, a layer of rust-proof material, such as metal nickel, etc., may be plated on the surface of the shell 110. Please refer to Figure 2 In an example of the secondary battery 100 of the present invention, the housing 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111. The end wall 111 is a closed end, and the opening 113 opposite to the end wall 111 is an open end. The end wall 111 and the side wall 112 can be integrally formed and connected, or they can be formed separately and then welded together.

[0060] like Figure 2 As shown, the electrode assembly 120 is contained in the housing 110. The electrode assembly 120 is a component in the secondary battery 100 where an electrochemical reaction occurs. The housing 110 may contain one or more electrode assemblies 120. The electrode assembly 120 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode collector; the positive electrode collector includes a positive electrode coating area and a positive electrode ear connected to the positive electrode coating area, the positive electrode coating area is coated with a positive electrode active material layer, and the positive electrode ear is not coated with a positive electrode active material layer. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode collector; the negative electrode collector includes a negative electrode coating area and a negative electrode ear connected to the negative electrode coating area, the negative electrode coating area is coated with a negative electrode active material layer, and the negative electrode ear is not coated with a negative electrode active material layer. Taking lithium-ion batteries as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material layer includes the positive electrode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide. The material of the negative electrode current collector can be copper, and the negative electrode active material layer includes the negative electrode active material, which can be carbon or silicon. The main material of the diaphragm can be PP or PE. In order to protect and insulate the electrode assembly 120, an insulating film can also be coated on the outside of the electrode assembly 120. The insulating film can be synthesized from PP, PE, PET, PVC or other high molecular polymer materials.

[0061] See also Figure 2In an example of the secondary battery 100 of the utility model, the electrode assembly 120 is sealed and installed in the housing 110, and the electrode assembly 120 is respectively provided with a first pole tab 121 and a second pole tab 122 at both ends in the length direction, and the first pole tab 121 and the second pole tab 122 have opposite polarities, wherein the first pole tab 121 faces the opening 113 of the housing 110, and the first pole tab 121 is a negative pole tab. It should be noted that in other embodiments, the first pole tab 121 may also be a positive pole tab, and the second pole tab 122 may be a negative pole tab.

[0062] Of course, under the premise of meeting the conduction requirements between the electrode assembly 120 and the shell 110, in other embodiments of the secondary battery 100 of the present invention, the first pole ear 121 and the second pole ear 122 with opposite polarities can also be arranged at the same end in the length direction of the electrode assembly 120, that is, the positive and negative poles of the secondary battery 100 are arranged on the same side.

[0063] See also Figure 2 In an example of the secondary battery 100 of the present invention, a through terminal mounting hole is provided on the end wall 111 of the housing 110, and the electrode terminal 190 is sealed and insulated and installed in the terminal mounting hole. As long as the sealing and insulation between the electrode terminal 190 and the end wall 111 can be achieved, the installation method of the electrode terminal 190 on the end wall 111 is not limited. The electrode assembly 120 has a second pole tab 122 on the side facing the end wall 111, and one end of the electrode terminal 190 can be directly welded to the second pole tab 122, or can be conductively connected to the second pole tab 122 through a current collecting member, and there is no specific limitation on this.

[0064] See also Figures 2 to 5In an example of the secondary battery 100 of the utility model, the end cap 140 is arranged on the side of the opening 113 of the shell 110, and the outer edge of the end cap 140 is welded to the side wall 112 of the shell 110, so that the end cap 140 is sealed and connected to the opening 113 of the shell 110; the structural form of the welding connection between the outer edge of the end cap 140 and the side wall 112 of the shell 110 is not limited, as long as the strength requirements and sealing requirements of the welding connection between the shell 110 and the end cap 140 are met. The end cap 140 includes a cover body 143 and a convex portion 141, the convex portion 141 is arranged around the outer periphery of the cover body 143, the convex portion 141 protrudes toward the direction of the electrode assembly 120, and the convex portion 141 supports the electrode assembly 120. In this embodiment, the convex portion 141 directly abuts against the first pole ear 121 arranged on the end surface of the electrode assembly 120 on the side facing the electrode assembly 120, so that the convex portion 141 plays an axial supporting role for the electrode assembly 120. It should be noted that during the use of the secondary battery 100, no matter the end cap 140 side of the secondary battery 100 is placed upward or downward, as long as there is a direct or indirect abutment force between the convex portion 141 and the electrode assembly 120, in the present utility model, it can be interpreted that the convex portion 141 supports the electrode assembly 120. The convex portion 141 and the cover body 143 can be connected by integral stamping or fixed by welding, etc., as long as the performance of the end cap 140 can be guaranteed. Preferably, in this embodiment, the convex portion 141 and the cover body 143 are integrally stamped parts. In this way, a higher molding efficiency of the end cap 140 can be obtained.

[0065] The convex portion 141 and the first pole ear 121 may or may not be welded, as long as the flow conduction requirements between the end cap 140 and the electrode assembly 120 are met. Preferably, in this embodiment, the convex portion 141 and the first pole ear 121 are welded and connected, so that a better stable and reliable flow conduction performance can be obtained between the end cap 140 and the electrode assembly 120. The convex portion 141 can be an annular structure coaxially arranged with the cover body 143, or an annular structure not coaxially arranged with the cover body 143, as long as the installation requirements of the end cap 140 are met. Preferably, in this embodiment, the convex portion 141 is a toroidal structure coaxially arranged with the cover body 143. It should be noted that in another embodiment, the convex portion 141 and the first pole ear 121 may not be welded, and a part of the cover body 143 may be concave toward the side of the electrode assembly 120 and welded after abutting against the first pole ear 121, so that the flow conduction requirements between the end cap 140 and the electrode assembly 120 can also be achieved.

[0066] Of course, in other embodiments of the secondary battery 100 of the present invention, such as Figures 6 to 8As shown, a current collecting component 130 may be further provided between the end cover 140 and the electrode assembly 120 , and the protrusion 141 may indirectly abut against the end surface of the electrode assembly 120 through the current collecting component 130 , thereby also realizing the support of the protrusion 141 to the electrode assembly 120 in the utility model.

[0067] See also Figure 3 and Figure 4 , the convex portion 141 includes a convex inner circumferential surface 1412 facing the axis side of the shell 110, and in the inner area surrounded by the convex portion 141, a second gap 160 is formed between the cover 143, the convex inner circumferential surface 1412 and the electrode assembly 120; inside the shell 110, the area between the convex inner circumferential surface 1412 and the side wall 112 of the shell 110 at least includes: a first gap 150 formed between the electrode assembly 120 and the side wall 112 of the shell 110 and an end face area of ​​the electrode assembly 120 that abuts against the convex portion 141. It should be noted that during the charge and discharge cycle of the secondary battery 100, as the electrode assembly 120 expands, the first gap 150 will gradually become smaller until it is invisible, but still allow a small amount of gas to pass through. In addition, the end face area of ​​the electrode assembly 120 that abuts against the convex portion 141 is usually formed with a tab stacking gap that is connected to the pole piece gap inside the electrode assembly 120.

[0068] A channel 170 is provided between the convex portion 141 and the electrode assembly 120, and the channel 170 connects the inner area surrounded by the inner circumferential surface 1412 of the convex portion and the area between the inner circumferential surface 1412 of the convex portion and the side wall 112. In this embodiment, the inner area surrounded by the inner circumferential surface 1412 of the convex portion is the second gap 160 mentioned above. In this embodiment, the channel 170 connects the inner area surrounded by the inner circumferential surface 1412 of the convex portion and the area between the inner circumferential surface 1412 of the convex portion and the side wall 112, that is, the channel 170 can connect only the first gap 150 and the second gap 160, or the channel 170 can connect only the second gap 160 and the end surface area of ​​the electrode assembly 120 abutting against the convex portion 141, or the channel 170 can connect the second gap 160 and the first gap 150, and connect the second gap 160 and the end surface area of ​​the electrode assembly 120 abutting against the convex portion 141.

[0069] It should be noted that in some other embodiments of the secondary battery 100 of the present invention, Figures 6 to 8As shown, when the convex portion 141 supports the electrode assembly 120 through the current collecting member 130, the second gap 160 is formed by the cover 143 located in the inner area of ​​the convex portion 141, the inner circumferential surface 1412 of the convex portion and the current collecting member 130. The specific structure of the channel 170 is not limited. When the convex portion 141 abuts against the electrode assembly 120, the channel 170 can be a through-groove structure provided on the convex portion 141; when the convex portion 141 abuts against the electrode assembly 120 indirectly through the current collecting member 130, the channel 170 can also be a through-hole structure provided on the current collecting member 130, or a through-groove or through-hole structure provided on both the current collecting member 130 and the convex portion 141, etc., as long as the inner area surrounded by the inner circumferential surface 1412 of the convex portion and the area between the inner circumferential surface 1412 of the convex portion and the side wall 112 can be connected.

[0070] The end surface of the electrode assembly 120 facing the end cover 140 includes a first pole ear 121, and a stacking gap 123 is formed at the first pole ear 121. During the charge and discharge cycle of the secondary battery 100, the gas generated by the electrode assembly 120 will be exhausted toward the first pole ear 121 side along the pole piece gap inside the electrode assembly 120, and then pass through the stacking gap 123 at the first pole ear 121 into the inner area surrounded by the inner peripheral surface 1412 of the convex portion, that is, the inside of the second gap 160, and finally discharged from the pressure relief position to achieve directional pressure relief of the secondary battery 100. However, since the protrusion 141 of the end cover 140 is supported on the end surface of the electrode assembly 120, the protrusion 141 and the end surface of the first pole ear 121 will be pressed against each other. On the one hand, this will make it difficult for the gas inside the electrode assembly 120 to enter the interior of the second gap 160 from the stacking gap 123 of the first pole ear 121; on the other hand, it will also block the connection between the first gap 150 and the second gap 160, making it difficult for the gas in the first gap 150 to be discharged through the second gap 160, thereby affecting the exhaust and pressure relief efficiency of the secondary battery 100 during thermal runaway and reducing the safety performance of the secondary battery 100.

[0071] In the embodiment of the utility model, by setting a channel 170 between the protrusion 141 of the end cover 140 and the electrode assembly 120, not only can the gas circulation effect between the first gap 150 and the second gap 160 be improved, but when the secondary battery 100 is thermally runaway, the gas in the first gap 150 can quickly enter the second gap 160 through the channel 170, and the gas stacking gap accumulated at the stacking gap 123 of the first pole ear 121 can also quickly enter the second gap 160 through the channel 170, and then quickly discharge from the explosion position, so that the gas can be prevented from accumulating inside the first gap 150 or in the stacking gap 123 of the first pole ear 121, causing the secondary battery 100 to have a lateral heat spread phenomenon, thereby ensuring that the secondary battery 100 can achieve directional pressure relief.

[0072] At the same time, since the setting of the channel 170 can increase the diffusion speed of the gas in the first gap 150 into the second gap 160, it is also beneficial that during the assembly process, the gas in the first gap 150 or the gas in the stacking gap 123 of the first pole ear 121 can be quickly discharged by vacuuming, thereby improving the efficiency of vacuuming during the injection and formation of the secondary battery 100, saving the time of vacuuming, and thus correspondingly increasing the injection and formation speed. On the other hand, when the secondary battery 100 is injected, the setting of the channel 170 can also speed up the circulation efficiency of the electrolyte between the second gap 160 and the first gap 150, and between the second gap 160 and the stacking gap 123 of the first pole ear 121, thereby effectively improving the injection efficiency of the secondary battery 100, shortening the infiltration time of the electrode assembly 120, and correspondingly improving the production efficiency of the secondary battery 100. In addition, providing a channel 170 between the protrusion 141 of the end cover 140 and the electrode assembly 120 can also reduce deformation generated during the assembly process of the end cover 140, and is more conducive to improving the installation accuracy between the end cover 140 and the shell 110 and the stability of the electrical connection between the end cover 140 and the electrode assembly 120.

[0073] See also Figures 3 to 5In an example of the secondary battery 100 of the utility model, the convex portion 141 also includes a convex outer peripheral surface 1413 on the side away from the axis of the shell 110. The convex outer peripheral surface 1413 can be coaxially arranged with the convex inner peripheral surface 1412, or it can be non-coaxially arranged, as long as the convex outer peripheral surface 1413 is a closed closed loop curved surface structure. Preferably, in this embodiment, the convex outer peripheral surface 1413 and the convex inner peripheral surface 1412 are coaxially arranged annular surface structures. The channel 170 includes a first recessed portion 1411, which is formed on the side of the convex portion 141 facing the electrode assembly 120, and the first recessed portion 1411 is recessed in the direction away from the electrode assembly 120, and the first recessed portion 1411 extends through the convex inner peripheral surface 1412 and the convex outer peripheral surface 1413. The first recess 1411 may be extended in a variety of ways, for example, the first recess 1411 may be extended in a curved shape, a straight line shape, a spiral line shape, or any other extension shape that can penetrate the inner circumference of the convex portion 141 and the outer circumference of the convex portion 141. Preferably, in an example of the secondary battery 100 of the utility model, the first recess 1411 extends in the radial direction of the secondary battery 100. In this way, the flow resistance generated when the gas or electrolyte flows through the first recess 1411 is small, which is more conducive to improving the flow efficiency of the gas or electrolyte between the first gap 150 and the second gap 160. Preferably, in this embodiment, four first recesses 1411 are provided, and the four first recesses 1411 are arranged in an array along the circumferential direction of the convex portion 141, so that the airflow distribution in the circumferential direction is more uniform, which is conducive to improving the consistency of the air pressure distribution inside the shell 110. Of course, in other embodiments, the first recess 1411 can also be set to other numbers and arrangements.

[0074] See also Figures 6 to 8 In an example of the secondary battery 100 of the utility model, the secondary battery 100 further includes a current collecting member 130, which is disposed in the housing 110 and is located on the side of the electrode assembly 120 facing the opening 113, and the current collecting member 130 is at least partially abutted between the convex portion 141 and the electrode assembly 120, and the current collecting member 130 is electrically connected to the first pole tab 121. The electrical connection method may be a welding connection, or a conductive adhesive bonding connection, etc. Preferably, in the present embodiment, the current collecting member 130 is welded to the first pole tab 121. The specific position and welding area of ​​the welding connection between the current collecting member 130 and the first pole tab 121 are not limited, as long as the stable electrical connection requirement between the current collecting member 130 and the first pole tab 121 can be achieved. The side of the current collecting member 130 facing the end cover 140 abuts against the protrusion 141 , so that the protrusion 141 is indirectly supported on the electrode assembly 120 through the current collecting member 130 , thereby supporting the electrode assembly 120 and the current collecting member 130 .

[0075] In some embodiments of the present invention, Figures 6 to 8 As shown, under the premise that the current collecting component 130 is provided on the side of the end cover 140, the channel 170 may only include a first recess 1411 provided on the convex portion 141, so that the first recess 1411 can connect the inner area surrounded by the inner circumferential surface 1412 of the convex portion and the area between the inner circumferential surface 1412 of the convex portion and the side wall 112, that is, connect the first gap 150 and the second gap 160 in the above-mentioned embodiment, or connect the second gap 160 in the above-mentioned embodiment and the stacking gap 123 of the first pole ear 121 at the position where the convex portion 141 and the current collecting component 120 are abutted.

[0076] It should be noted that when the convex portion 141 abuts against the current collecting member 130, the current collecting member 130 will correspondingly compress the stacking gap 123 of the first pole ear 121 below, so that during the charging and discharging process of the secondary battery 100, when the gas generated by the electrode assembly 120 is exhausted toward the first pole ear 121 side along the pole sheet gap, at the corresponding position below the convex portion 141, since the end faces of the current collecting member 130 and the first pole ear 121 are pressed against each other, it will be difficult for the gas inside the electrode assembly 120 to enter the second gap 160 from the stacking gap 123 of the first pole ear 121, as shown in FIG. Fig.11 shown.

[0077] In view of this, in an example of the secondary battery 100 of the present invention, as Figures 9 to 12 As shown, the current collecting member 130 is also provided with a through hole 131, which penetrates the current collecting member 130 in the thickness direction and is provided at the outer periphery of the current collecting member 130; along the height direction of the through hole 131, the side of the through hole 131 away from the convex portion 141 is connected to the stacking gap 123 of the first pole tab 121, and the side of the through hole 131 facing the convex portion 141 is connected to the second gap 160, thereby realizing the mutual communication between the stacking gap 123 of the first pole tab 121 and the second gap 160 at the position where the convex portion 141 abuts against the current collecting member 120. The specific shape of the through hole 131 is not limited, and can be any through hole shape that can connect the stacking gap 123 of the first pole tab 121 with the second gap 160, such as a circular hole, an elongated hole or a rectangular hole.

[0078] See also Fig. 9In this embodiment, a plurality of through holes 131 are provided on the current collecting member 130, and the plurality of through holes 131 are arranged around the outer periphery of the current collecting member 130. In other embodiments, one through hole 131 may also be provided, and this is not limited. By providing the through hole 131 on the current collecting member 130, the gas at the stacking gap 123 of the first pole tab 121 can enter the interior of the second gap 160 through the through hole 131 on the current collecting member 130 below the convex portion 141, and play the role of the channel 170, thereby improving the communication effect between the stacking gap 123 of the first pole tab 121 and the second gap 160, that is, improving the communication effect between the inner area surrounded by the inner circumferential surface 1412 of the convex portion and the area between the inner circumferential surface 1412 of the convex portion and the side wall 112. At the same time, the provision of the through hole 131 can also reduce the weight of the current collecting member 130, thereby reducing the overall weight of the secondary battery 100 and improving the mass density of the secondary battery 100.

[0079] Preferably, see Fig.11 and Fig.12 In an example of the secondary battery 100 of the utility model, the through hole 131 is an elongated through hole 131 extending in the radial direction of the current collecting member 130. In this way, under the same area, the elongated through hole 131 extends longer in the radial direction of the current collecting member 130, so that the flow efficiency between the stacking gap 123 of the first pole tab 121 and the second gap 160 can be increased, so that the flow efficiency of the gas between the stacking gap 123 of the first pole tab 121 and the second gap 160 can be further improved, and at the same time, the gas discharge speed at the stacking gap 123 of the first pole tab 121 and the flow speed of the electrolyte between the stacking gap 123 of the first pole tab 121 and the second gap 160 can be further improved; in addition, the elongated through hole 131 extends shorter in the circumferential direction of the current collecting member 130, so that the abutment area between the convex portion 141 and the current collecting member 130 can be reduced, the abutment and pressing effect can be ensured, and the stability of the conductive connection between the current collecting member 130 and the end cover 140 can be improved. It should be noted that, in this embodiment, a plurality of elongated through holes 131 are provided on the current collecting member 130, and the plurality of elongated through holes 131 are arranged along the central array of the current collecting member 130 on the outer periphery of the current collecting member 130. This arrangement enables the stacking gap 123 of the first electrode tab 121 to obtain a more uniform exhaust effect in the circumferential direction.

[0080] In order to further increase the flow rate of the gas or electrolyte in the housing 110 in the through hole 131, please refer to Fig.13In this embodiment, the through hole 131 extends through the outer edge of the current collecting member 130 in the radial direction of the current collecting member 130. In this way, a through opening is formed on the side of the through hole 131 facing the first gap 150. The setting of the through opening can not only increase the communication area between the stacking gap 123 of the first pole tab 121 and the second gap 160 in the radial direction, but also connect the first gap 150 with the second gap 150, so that the gas in the first gap 150 can be discharged into the second gap 160 through the through hole 131. Therefore, this setting can further increase the speed at which the gas in the stacking gap 123 of the first pole tab 121 is discharged into the second gap 160 through the through hole 131, and can also increase the speed at which the gas in the first gap 150 is discharged into the second gap 160, so that the exhaust pressure relief effect of the secondary battery 100 during thermal runaway can be further improved.

[0081] See also Fig.10 and Fig.11 In an example of the secondary battery 100 of the present invention, an abutment area 142 is formed between the convex portion 141 and the current collecting member 130, at least a portion of the through hole 131 extends to the abutment area 142, and at least another portion of the through hole 131 extends to the radial inner side of the convex portion 141. The portion of the through hole 131 located in the abutment area 142 is connected to the stacking gap 123 of the first pole tab 121, and the portion of the through hole 131 extending to the radial inner side of the convex portion 141 is connected to the second gap 160, thereby achieving communication between the stacking gap 123 of the first pole tab 121 at the position of the abutment area 142 and the second gap 160. With such arrangement, on the one hand, the gas generated in the stacking gap 123 of the first pole ear 121 can be discharged into the second gap 160 through the through hole 131, which can further reduce the retention of gas in the stacking gap 123 of the first pole ear 121 and ensure the pressure relief and exhaust effect of the secondary battery 100; on the other hand, the portion of the through hole 131 extending to the radial inner side of the protrusion 141 can also reduce the obstruction of the end face of the first pole ear 121, which is beneficial for the gas in the gap between the pole pieces inside the electrode assembly 120 to be discharged from the through hole 131 into the second gap 160, further improving the exhaust and pressure relief effect of the secondary battery 100 during thermal runaway.

[0082] Along the radial direction of the secondary battery 100, the longer the length of the abutment area 142 between the protrusion 141 and the current collecting member 130 is, the better the abutment and compression effect on the current collecting member 130 is, but correspondingly, it is less conducive to the outward diffusion of the gas in the first gap 150; conversely, the gas diffusion effect is better and the compression effect is worse. Preferably, please refer to Fig.11In an example of the secondary battery 100 of the utility model, the length of the through hole 131 along the radial direction of the secondary battery 100 is greater than or equal to 1 / 2 of the length of the abutment area 142 along the radial direction of the secondary battery 100. In this way, a better exhaust speed can be obtained between the stacking gap 123 of the first electrode 121 and the through hole 131, and the abutment area between the protrusion 141 and the current collecting member 130 can be ensured, thereby ensuring the stability of the electrical connection of the current collecting member 130.

[0083] In another embodiment of the present invention, on the basis of the current collecting component 130 being provided with the through hole 131 in the above embodiment, the convex portion 141 is further provided with the first concave portion 1411 in the above embodiment. Figures 14 to 16 As shown. The positional relationship between the first recess 1411 and the through hole 131 is not limited. For example, the first recess 1411 may partially overlap with the through hole 131, or may be arranged at intervals along the circumferential direction of the end current collecting member 130. In this way, the gas in the first gap 150 and the gas in the stacking gap 123 of the first pole tab 121 can enter the second gap 160 partially through the first recess 1411, and can also enter the second gap 160 partially through the through hole 131, so that more connecting channels 170 can be formed between the second gap 160 and the stacking gap 123 of the first pole tab 121, and between the second gap 160 and the first gap 150, so that the gas flow efficiency and the flow speed of the electrolyte between the second gap 160 and the first gap 150, and between the second gap 160 and the stacking gap 123 of the first pole tab 121 can be further improved.

[0084] For further information, see Figures 14 to 16In an example of the secondary battery 100 of the utility model, at least some of the multiple through holes 131 opened on the outer periphery of the current collecting member 130 are arranged correspondingly to the first recess 1411; corresponding arrangement means that along the thickness direction of the end cover 140, an overlapping area is formed between the orthographic projection of the first recess 1411 on the current collecting member 130 and the through hole 131, so that the combination of the first recess 1411 and the through hole 131 connects the second gap 160 and the first gap 150, and the second gap 160 and the stacking gap 123 of the first electrode tab 121. The specific size of the overlapping area is not limited. Preferably, in this embodiment, the orthographic projection of the first recess 1411 on the current collecting member 130 completely covers the width dimension of the through hole 131 in the circumferential direction. In this way, a larger channel 170 area can be formed between the convex portion 141 and the current collecting member 130, so that the gas or electrolyte inside the housing 110 can flow more quickly between the first gap 150 and the second gap 160, and between the second gap 160 and the stacking gap 123 of the first electrode tab 121, thereby further improving the flow rate of the gas or electrolyte inside the housing 110. It should be noted that the number of the first recesses 1411 and the through holes 131 can be equal or unequal, as long as a part of the through holes 131 and the first recesses 1411 have an overlapping area in their orthographic projection on the current collecting member 130.

[0085] See also Figures 17 to 19In an example of the secondary battery 100 of the utility model, the current collecting component 130 includes a current collecting body 133 and a thickened portion 132 arranged on the side of the current collecting body 133 facing the convex portion 141, and the thickened portion 132 is located at the outer periphery of the current collecting body 133, and abuts against the side of the convex portion 141 facing the electrode assembly 120. The thickened portion 132 can be a circular ring structure coaxially arranged with the convex portion 141, or a ring structure of other shapes that is not coaxially arranged with the convex portion 141, as long as an annular abutment area is formed between the convex portion 141 and the thickened portion 132. Preferably, in the present embodiment, the thickened portion 132 is coaxially arranged with the convex portion 141, which can facilitate the positioning between the thickened portion 132 and the convex portion 141, and can also obtain a better abutment area. The thickened portion 132 and the current collecting body 133 can be connected by an integral molding, or by any connection method such as welding connection. Preferably, in this embodiment, the thickened portion 132 and the current collecting body 133 are connected by welding, which facilitates the processing and forming of the current collecting member 130. By arranging the thickened portion 132 on the current collecting member 130, and making the thickened portion 132 abut against the convex portion 141 for welding connection, when the convex portion 141 and the current collecting member 130 are welded on the side of the end cover 140, the probability of the current collecting member 130 being welded through can be reduced, and the welding process window between the end cover 140 and the current collecting member 130 can be improved, and then under the condition of meeting the welding quality, the welding efficiency between the end cover 140 and the current collecting member 130 can be correspondingly improved.

[0086] For further information, please refer to Figures 17 to 19In one embodiment of the utility model, the thickened portion 132 includes a thickened portion inner circumferential surface 1322 facing the axis of the housing 110 and a thickened portion outer circumferential surface 1323 facing away from the axis of the housing 110. A second recess 1321 is also provided on the thickened portion 132, and the second recess 1321 is recessed toward the side away from the convex portion 141, and the second recess 1321 extends through the thickened portion inner circumferential surface 1322 and the thickened portion outer circumferential surface 1323. The second recess 1321 can be extended in a variety of ways, for example, the second recess 1321 can be extended in a curved shape, a straight line shape, a spiral line shape, or any other extension that can horizontally penetrate the thickened portion inner circumferential surface 1322 and the thickened portion outer circumferential surface 1323. By providing the second recess 1321 on the thickened portion 132, the gas or electrolyte in the housing 110 can flow between the first gap 150 and the second gap 160, and between the second gap 160 and the stacking gap 123 of the first pole tab 121 through the second recess 1321, so that the flow efficiency of the gas or electrolyte in the housing 110 between the first gap 150 and the second gap 160, and between the second gap 160 and the stacking gap 123 of the first pole tab 121 can be improved. At the same time, the second recess 1321 provided on the thickened portion 132 can also reduce the weight of the current collecting member 130, so the overall weight of the secondary battery 100 can be reduced, and the mass density of the secondary battery 100 can be improved.

[0087] It should be noted that in some embodiments of the present invention, Fig.17 and Fig.18 As shown, under the premise that the first recess 1411 in the above embodiment is not provided on the convex portion 141 of the end cover 140, the second recess 1321 in the above embodiment can be opened only on the thickened portion 132 of the current collecting member 130. In this way, the connection between the first gap 150 and the second gap 160, and the connection between the second gap 160 and the stacking gap 123 of the first pole ear 121 can be fully achieved only through the second recess 1321, thereby improving the flow effect of the gas or electrolyte inside the shell 110 between the first gap 150 and the second gap 160, and between the second gap 160 and the stacking gap 123 of the first pole ear 121.

[0088] In some other embodiments of the present invention, Fig. 20 and Fig. 22As shown, on the basis of the first recess 1411 in the above-mentioned embodiment being provided on the convex portion 141, a second recess 1321 is also provided on the thickened portion 132. In this way, the gas or electrolyte in the housing 110 can flow between the first gap 150 and the second gap 160 and between the second gap 160 and the stacking gap 123 of the first pole tab 121 through the first recess 1411, and can also flow between the first gap 150 and the second gap 160 and between the second gap 160 and the stacking gap 123 of the first pole tab 121 through the second recess 1321. Therefore, the flow effect of the gas or electrolyte in the housing 110 between the first gap 150 and the second gap 160 and between the second gap 160 and the stacking gap 123 of the first pole tab 121 can be further improved.

[0089] Preferably, in an example of the secondary battery 100 of the present invention, the second recess 1321 extends along the radial direction of the secondary battery 100. In this way, the flow resistance generated when the gas or electrolyte in the shell 110 flows through the second recess 1321 is small, which is more conducive to improving the flow speed of the gas or electrolyte in the shell 110 between the first gap 150 and the second gap 160, and between the second gap 160 and the stacking gap 123 of the first tab 121.

[0090] In order to further increase the flow rate of gas or electrolyte between the first gap 150 and the second gap 160, and between the second gap 160 and the stacking gap 123 of the first electrode tab 121, further, please refer to Figure 20 to Figure 22In an example of the secondary battery 100 of the utility model, the second recess 1321 and the first recess 1411 provided on the thickened portion 132 are at least partially provided correspondingly; the corresponding provision means that, along the thickness direction of the end cover 140, an overlapping area is formed between the orthographic projection of the first recess 1411 on the current collecting member 130 and the orthographic projection of the second recess 1321, so that the first recess 1411 and the second recess 1321 are combined to connect the first gap 150 and the second gap 160. The specific size of the overlapping area is not limited. Preferably, in this embodiment, the orthographic projection of the first recess 1411 on the current collecting member 130 completely covers the width dimension of the second recess 1321 in the circumferential direction. In this way, a larger channel 170 area can be formed between the convex portion 141 and the current collecting member 130, so that the gas or electrolyte inside the housing 110 can flow more quickly between the first gap 150 and the second gap 160, and between the second gap 160 and the stacking gap 123 of the first electrode tab 121, thereby further improving the flow rate of the gas or electrolyte inside the housing 110. It should be noted that the number of the first recessed portions 1411 and the second recessed portions 1321 can be equal or unequal, as long as a part of the second recessed portions 1321 and the first recessed portions 1411 have an overlapping area in their orthographic projection on the current collecting member 130.

[0091] In order to facilitate the welding connection between the end cover 140 and the side wall 112, in an example of the secondary battery 100 of the present invention, as shown in FIG. Figure 4 and Figure 7 As shown, the end cover 140 further includes an extension portion 146, which is disposed around the outer periphery of the protrusion 141, and extends outward along the circumferential outer edge of the end cover 140, and the outer diameter of the extension portion 146 is greater than the inner diameter of the side wall 112 of the housing 110 at the position of the opening 113. The side wall 112 includes an end face 1121 at one side of the opening 113, and when the end cover 140 is installed at the opening 113 of the housing 110, the extension portion 146 overlaps the end face 1121 and is fixedly connected to the end face 1121 by welding, so as to achieve a sealed welding between the end cover 140 and the housing 110. Since the radial inner side of the extension portion 146 is provided with the protrusion 141, on the one hand, the protrusion 141 can play a role in shielding the laser when the extension portion 146 is welded to the end face of the side wall 112, thereby protecting the electrode assembly 120 and the like inside the shell 110 from damage; on the other hand, when the extension portion 146 is welded to the side wall 112, part of the welding molten pool can be formed on the outer peripheral surface of the protrusion 141, thereby forming a welding fixing point between the side wall 112 and the protrusion 141, further improving the sealing performance and connection strength between the side wall 112 and the end cover 140.

[0092] Further, in an example of the secondary battery 100 of the present invention, as Figure 4As shown, along the thickness direction of the end cover 140, the height H of the protrusion 141 protruding from the extension portion 146 is 2.0 to 4.0 mm. For example, H can be any value between 2.0 and 4.0 mm, such as 2.0 mm, 2.5 mm, 3.0 mm or 4 mm. In this embodiment, the height H is limited to between 2.0 and 4.0 mm, so that the protrusion 141 can have a good welding laser shielding effect in the height direction, and at the same time, the second gap 160 can have a better height, ensuring the gas storage space of the second gap 160 to meet the normal pressure relief requirements of the secondary battery 100.

[0093] See also Figure 3 and Figure 6 In an example of the secondary battery 100 of the utility model, the secondary battery 100 further includes an explosion-proof valve 180, which is disposed on the end cap 140 and is located on the side of the convex portion 141 close to the center of the electrode assembly 120. The explosion-proof valve 180 can be any explosion-proof structure such as an explosion-proof notch, an explosion-proof valve sheet, etc. In this embodiment, the explosion-proof valve 180 is an explosion-proof notch disposed on the end cap 140, and the explosion-proof notch is located in the inner area surrounded by the convex portion 141, so the explosion-proof notch corresponds to the second gap 160. When thermal runaway occurs in the secondary battery 100, the explosion-proof notch will rupture, and the gas collected in the second gap 160 will be discharged from the rupture first. In the secondary battery 100 in the above embodiment, since a channel 170 is provided between the first gap 150 and the second gap 160, the gas in the first gap 150 can be quickly discharged into the second gap 160, and then quickly discharged from the rupture of the explosion-proof notch, thereby preventing high-pressure gas from being retained in the first gap 150 and causing lateral heat spread in the secondary battery 100, resulting in more serious consequences.

[0094] See also Figure 3 and Figure 5In an example of the secondary battery 100 of the utility model, an injection hole 145 is further provided on the end cover 140, and the injection hole 145 is located in the inner area surrounded by the convex portion 141. The injection hole 145 can be arranged in the central area of ​​the end cover 140, or it can be deviated from the central area of ​​the end cover 140, as long as the injection requirements of the injection hole 145 are met, and there is no specific limitation on this. Preferably, in this embodiment, the injection hole 145 is a circular hole structure coaxially arranged with the end cover 140. Such an arrangement not only facilitates the positioning between the injection device and the injection hole 145, but also allows the injection hole 145 to correspond to the central hole of the electrode assembly 120, which is beneficial to improving the injection efficiency of the secondary battery 100. In order to seal the injection hole 145 on the end cover 140, in this embodiment, the secondary battery 100 also includes a cover plate 147, which is mounted on the end cover 140 to cover the injection hole 145. There is no limit to the way in which the cover plate 147 covers the injection hole 145. For example, the cover plate 147 can be adhesively connected to the injection hole 145, or it can be snapped onto the injection hole 145 by interference fit installation, or it can be sealed at the injection hole 145 by sealing welding, as long as the sealing requirements of the injection hole 145 can be met.

[0095] It should be noted that the injection hole 145 in the above embodiment may not be provided on the end cap 140, but may be provided on the side of the end wall 111 of the housing 110, and such a provision may also play a role in injecting liquid into the electrode assembly 120. When the injection hole 145 is provided on the side of the end wall 111, the injection hole 145 may be provided on the electrode terminal 190 or on the end wall 111, and this is not limited.

[0096] See also Fig.23 In one embodiment of the battery pack 200 of the utility model, the battery pack 200 includes a box body 210 and at least one secondary battery 100; the box body 210 includes 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 cover each other to form a receiving space, and multiple secondary batteries 100 are received in the receiving space, 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.

[0097] See also Fig.24In an example of the electronic device 300 of the utility model, the electronic device 300 includes 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 that can obtain power from the battery pack 200 and perform corresponding work, such as a fan blade rotation unit, a vacuum cleaner unit, a wheel drive unit in an electric car, etc. The electronic device 300 can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.; the spacecraft includes airplanes, rockets, space shuttles and spacecrafts, etc.; the electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.; the electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers, etc. The embodiment of the utility model does not impose any special restrictions on the above-mentioned electronic device 300. In one embodiment of the electronic device 300 of the utility model, the electronic device 300 is a vehicle, the working part 310 is the body of the vehicle, and the battery pack 200 is fixedly installed on the body, thereby providing driving force for the vehicle to realize the operation of the vehicle.

[0098] The utility model secondary battery, by setting a channel between the convex part and the electrode assembly, and making the channel communicate with the inner area surrounded by the inner circumference of the convex part and the area between the inner circumference of the convex part and the side wall, so that, on the one hand, the circulation of gas in the inner area surrounded by the inner circumference of the convex part and the area between the inner circumference of the convex part and the side wall can be accelerated. When the secondary battery is thermally runaway, the gas generated in the area between the inner circumference of the convex part and the side wall can quickly enter the inner area and be discharged from the explosion position, thereby preventing the secondary battery from lateral heat spread phenomenon, causing more serious consequences. At the same time, when the secondary battery is filled and vacuumed during the formation process, the gas in the area between the inner circumference of the convex part and the side wall can quickly flow into the inner area surrounded by the inner circumference of the convex part through the channel, so that the exhaust speed in the secondary battery can be accelerated, the vacuuming time can be saved, and the gas can be avoided from being retained inside the shell, so as to ensure the vacuuming effect, thereby ensuring the effect of filling and forming. On the other hand, when the secondary battery is filled, the setting of the channel can also accelerate the circulation speed of the electrolyte inside the shell, so as to effectively improve the filling efficiency of the secondary battery. Therefore, the utility model effectively overcomes some practical problems in the prior art and thus has high utilization value and use significance. The above embodiments are only illustrative of the principle and efficacy of the utility model, and are not used to limit the utility model. Anyone familiar with this technology can modify or change the above embodiments without violating the spirit and scope of the utility model. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the relevant technical field without departing from the spirit and technical ideas disclosed by the utility model should still be covered by the claims of the utility model.

Claims

1. A secondary battery, characterized in that: include: a housing including a side wall, the side wall including an opening; An electrode assembly is disposed in the housing; An end cap, sealing the opening, wherein the outer periphery of the end cap includes a convex portion that is disposed around and protrudes toward the electrode assembly, and the radial inner side of the convex portion includes an inner circumferential surface of the convex portion; The convex portion supports the electrode assembly, and a channel is provided between the convex portion and the electrode assembly, and the channel connects an inner area surrounded by an inner circumferential surface of the convex portion and an area between the inner circumferential surface of the convex portion and the side wall.

2. The secondary battery according to claim 1, characterized in that: A first gap is formed between the electrode assembly and the side wall, a second gap is formed between the end cover and the electrode assembly, and the channel connects the first gap and the second gap.

3. The secondary battery according to claim 1, characterized in that: The radial outer side of the protrusion includes an outer peripheral surface of the protrusion, and the channel includes a first recessed portion arranged on the surface of the protrusion facing the electrode assembly, the first recessed portion is recessed in a direction away from the electrode assembly and extends through the inner peripheral surface of the protrusion and the outer peripheral surface of the protrusion.

4. The secondary battery according to claim 3, characterized in that: The first recess extends in a radial direction of the secondary battery.

5. The secondary battery according to claim 3, characterized in that: The electrode assembly has a first electrode tab on one side facing the opening, and the protrusion abuts against the first electrode tab.

6. The secondary battery according to any one of claims 3 to 4, characterized in that: The electrode assembly has a first electrode tab on a side facing the opening. The secondary battery further includes a current collecting member, which is at least partially sandwiched between the protrusion and the electrode assembly and electrically connected to the first electrode tab.

7. The secondary battery according to claim 6, characterized in that: The channel further comprises a through hole arranged at the outer periphery of the current collecting member, an abutment area is formed between the convex portion and the current collecting member, and the through hole at least partially extends to the abutment area and at least another part extends to the radial inner side of the convex portion.

8. The secondary battery according to claim 7, characterized in that: At least part of the through holes is arranged corresponding to the first recess.

9. The secondary battery according to claim 7, characterized in that: The length of the through hole along the radial direction of the secondary battery is greater than or equal to 1 / 2 of the length of the abutting area along the radial direction of the secondary battery.

10. The secondary battery according to claim 7, characterized in that: The through hole extends in a radial direction of the current collecting member and penetrates an outer edge of the current collecting member.

11. The secondary battery according to claim 6, characterized in that: The current collecting member includes a thickened portion welded to the convex portion on one side thereof facing the convex portion.

12. The secondary battery according to claim 11, characterized in that: The thickened portion includes an inner circumferential surface of the thickened portion facing the axis of the shell and an outer circumferential surface of the thickened portion facing away from the axis of the shell; the channel also includes a second recessed portion arranged in the thickened portion, the second recessed portion is recessed toward the side away from the convex portion, and the second recessed portion extends through the inner circumferential surface of the thickened portion and the outer circumferential surface of the thickened portion.

13. The secondary battery according to claim 1, characterized in that: The secondary battery further includes an explosion-proof valve, which is disposed on the end cover and located in an inner area surrounded by the inner circumference of the convex portion.

14. The secondary battery according to claim 1, characterized in that: The end cover is provided with a liquid injection hole, and the liquid injection hole is located in the inner area surrounded by the inner peripheral surface of the convex part.

15. The secondary battery according to claim 1, characterized in that: The end cover also includes an extension portion arranged around the outer periphery of the protrusion, the side wall located on one side of the opening includes an end face, the extension portion overlaps the end face and is fixed to the end face by welding; along the thickness direction of the end cover, the height of the protrusion protruding from the extension portion is 2.0 to 4.0 mm.

16. A secondary battery, characterized in that: include: a housing including a side wall, the side wall including an opening; An electrode assembly is disposed in the housing, and a side of the electrode assembly facing the opening has a first electrode tab; a current collecting member, disposed on a side of the electrode assembly facing the opening, and the current collecting member is electrically connected to the first electrode tab; An end cap, sealing the opening, wherein a convex portion protruding toward the electrode assembly is disposed around the outer periphery of the end cap, and the radial inner side of the convex portion includes an inner peripheral surface of the convex portion; The convex portion abuts against the current collecting component, and the current collecting component is provided with a channel, and the channel communicates an inner area surrounded by the inner circumference of the convex portion and an area between the inner circumference of the convex portion and the side wall.

17. The secondary battery according to claim 16, characterized in that: The channel includes a through hole arranged at the outer periphery of the current collecting member, an abutment area is formed between the convex portion and the current collecting member, and the through hole at least partially extends to the abutment area and at least another part extends to the radial inner side of the convex portion.

18. The secondary battery according to claim 17, characterized in that: The through hole is an elongated through hole extending in a radial direction of the current collecting member.

19. The secondary battery according to claim 17, characterized in that: The length of the through hole along the radial direction of the secondary battery is greater than or equal to 1 / 2 of the length of the abutting area along the radial direction of the secondary battery.

20. The secondary battery according to claim 17, characterized in that: The through hole extends through an outer edge of the current collecting member in a radial direction of the current collecting member.

21. The secondary battery according to claim 16, characterized in that: The side of the current collecting component facing the convex portion includes a thickened portion that abuts against and is welded to the convex portion, and the thickened portion includes an inner circumferential surface of the thickened portion facing the axis of the shell and an outer circumferential surface of the thickened portion facing away from the axis of the shell; the channel includes a second recessed portion arranged in the thickened portion, and the second recessed portion is recessed toward the side away from the convex portion, and the second recessed portion extends through the inner circumferential surface of the thickened portion and the outer circumferential surface of the thickened portion.

22. A battery pack, characterized in that: A secondary battery comprising the secondary battery according to any one of claims 1 to 21.

23. An electronic device, characterized in that: A battery pack comprising the battery pack of claim 22.

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