Secondary battery, battery pack, and electronic device

Abstract

Provided are a secondary battery, a battery pack, and an electronic device. The secondary battery comprises a case, an electrode assembly, and an end cover, wherein the case comprises a side wall, which comprises an opening; the electrode assembly is arranged in the case; and the end cover seals the opening, the periphery of the end cover comprising a surrounding protrusion which protrudes towards the electrode assembly, and the inner radial side of the protrusion comprising an inner peripheral surface. The protrusion supports the electrode assembly, and a channel is provided between the protrusion and the electrode assembly, the channel communicating an inner area enclosed by the inner peripheral surface of the protrusion and an area between the inner peripheral surface of the protrusion and the side wall. By providing a channel in a region where the end cover abuts against a current collecting member, the gas venting rate of the secondary battery can be increased, and the efficiency of electrolyte injection, impregnation, and formation of the secondary battery can also be improved.

Description

Secondary batteries, battery packs, and electronic devices Technical Field

[0001] The present disclosure relates to the field of battery technology, and in particular to secondary batteries, battery packs, and electronic devices. Background Art

[0002] With the development of lithium battery technology, the demand for battery cell energy density is becoming increasingly higher. Secondary batteries have become one of the current mainstream battery cell forms due to their high assembly efficiency. The end caps and shells of secondary batteries can be welded together. During the welding process, to prevent the laser from entering the shell and damaging the internal structure of the secondary battery, the outer periphery of the end caps is generally provided with a surrounding protrusion. The protrusion blocks the laser from entering the shell. Inside the shell, the protrusion contacts the electrode assembly or current collecting member, thus affecting the flow and diffusion rate of gas in the secondary battery. This in turn affects the pressure relief and exhaust efficiency of the secondary battery during thermal runaway, reducing the safety performance of the secondary battery.

[0003] Public content

[0004] The present disclosure provides a secondary battery, a battery pack, and an electronic device to improve the pressure relief and exhaust efficiency of the secondary battery during thermal runaway, thereby ensuring the safety performance of the secondary battery.

[0005] To achieve the above-mentioned objectives and other related objectives, the present disclosure provides a secondary battery, comprising: a shell, an electrode assembly and an end cover; the shell comprises a side wall, the side wall comprises an opening; the electrode assembly is arranged in the shell; the end cover seals the opening, the outer periphery of the end cover comprises a convex portion arranged around and protruding toward the electrode assembly, the radial inner side of the convex portion comprises an inner peripheral 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 peripheral surface of the convex portion and the area between the inner peripheral surface of the convex portion and the side wall.

[0006] In an example of the secondary battery disclosed herein, 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.

[0007] In an example of a secondary battery disclosed herein, 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 and the outer peripheral surface of the protrusion.

[0008] In one example of the secondary battery of the present disclosure, the first recess extends in a radial direction of the secondary battery.

[0009] In an example of the secondary battery disclosed herein, the electrode assembly has a first tab on a side facing the opening, and the protrusion abuts against the first tab.

[0010] In an example of the secondary battery disclosed herein, the electrode assembly has a first tab on a side facing the opening, and the secondary battery further includes a current collecting member that is at least partially clamped between the protrusion and the electrode assembly and electrically connected to the first tab.

[0011] In an example of the secondary battery disclosed herein, the channel further comprises a through hole provided on the outer periphery of the current collecting member, an abutment area is formed between the protrusion and the current collecting member, the through hole at least partially extends to the abutment area, and at least another portion extends to the radial inner side of the protrusion.

[0012] In an example of the secondary battery of the present disclosure, at least a portion of the through holes is disposed corresponding to the first recess.

[0013] In an example of the secondary battery of the present disclosure, a length of the through hole along the radial direction of the secondary battery is greater than or equal to 1 / 2 of a length of the abutting area along the radial direction of the secondary battery.

[0014] In an example of the secondary battery of the present disclosure, the through hole extends in a radial direction of the current collecting member and penetrates the outer edge of the current collecting member.

[0015] In an example of the secondary battery of the present disclosure, a side of the current collecting member facing the protrusion includes a thickened portion welded to the protrusion.

[0016] In an example of the secondary battery disclosed in the present invention, 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.

[0017] In an example of the secondary battery disclosed herein, 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.

[0018] In an example of the secondary battery disclosed herein, the end cap is provided with a liquid injection hole, and the liquid injection hole is located in the inner area surrounded by the inner circumference of the convex portion.

[0019] In an example of the secondary battery disclosed herein, the end cap further includes an extension portion arranged around the 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 cap, the height of the protrusion protruding from the extension portion is 2.0 to 4.0 mm.

[0020] The present disclosure also provides a secondary battery, comprising: a shell, an electrode assembly, a current collecting member 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 electrode tab; the current collecting member is arranged on the side of the electrode assembly facing the opening, and the current collecting member is electrically connected to the first electrode tab; 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 member, and the current collecting member 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.

[0021] In an example of the secondary battery disclosed herein, the channel includes a through hole provided 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 portion extends to the radial inner side of the protrusion.

[0022] In an example of the secondary battery of the present disclosure, the through hole is an elongated through hole extending in a radial direction of the current collecting member.

[0023] In an example of the secondary battery disclosed herein, a length of the through hole along a radial direction of the secondary battery is greater than or equal to 1 / 2 of a length of the abutting area along the radial direction of the secondary battery.

[0024] In one example of the secondary battery of the present disclosure, the through hole extends through the outer edge of the current collecting member in a radial direction of the current collecting member.

[0025] In an example of a secondary battery disclosed in the present invention, the side of the current collecting component facing the convex portion includes a thickened portion that abuts 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.

[0026] The present disclosure also provides a battery pack including the secondary battery in any one of the above examples.

[0027] The present disclosure further provides an electronic device, which includes the above-mentioned battery pack.

[0028] The secondary battery disclosed herein is provided with a channel between the convex portion and the electrode assembly, and the channel is connected to the inner area surrounded by the inner circumference of the convex portion and the area between the inner circumference of the convex portion and the side wall. This arrangement, on the one hand, can accelerate the flow of gas between the inner area surrounded by the inner circumference of the convex portion and the area between the inner circumference of the convex portion and the side wall. When the secondary battery is in thermal runaway, the gas generated in the area between the inner circumference of the convex portion and the side wall can enter the inner area surrounded by the inner circumference of the convex portion 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 with liquid and vacuumed during formation, the gas in the area between the inner circumference of the convex portion and the side wall can quickly flow into the inner area surrounded by the inner circumference of the convex portion through the channel. This can not only accelerate the exhaust speed in the secondary battery and save vacuuming time, but also avoid the retention of gas inside the shell, ensuring the vacuuming effect, thereby ensuring the effect of filling and formation. On the other hand, when the secondary battery is filled with liquid, the arrangement 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 cover and the electrode assembly can also reduce deformation during the assembly of the end cover, and is more conducive to improving the installation accuracy between the end cover and the shell and the stability of the electrical connection between the end cover and the electrode assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] FIG1 is a three-dimensional overall schematic diagram of an embodiment of a secondary battery disclosed herein;

[0031] FIG2 is a cross-sectional view of the overall structure of an embodiment of a secondary battery disclosed herein;

[0032] FIG3 is a partial enlarged view of area A in FIG2 ;

[0033] FIG4 is a partial enlarged view of a channel provided between the protrusion and the electrode assembly in the embodiment of FIG3 ;

[0034] FIG5 is a schematic diagram of the overall structure of an end cap in one embodiment of a secondary battery disclosed herein;

[0035] FIG6 is a schematic structural diagram of a secondary battery according to an embodiment of the present disclosure, in which a channel is provided between a protrusion and a current collecting member;

[0036] FIG7 is a partial enlarged schematic diagram of a channel provided between the convex portion and the current collecting member in the embodiment of FIG6 ;

[0037] FIG8 is a schematic diagram of the installation positions of the end cover and the current collecting member in the embodiment shown in FIG6 ;

[0038] FIG9 is a schematic diagram of the installation positions of the current collecting member and the end cover in one embodiment of the secondary battery disclosed herein;

[0039] FIG10 is a schematic diagram of a partial structure of an end cap side of another embodiment of a secondary battery disclosed herein;

[0040] FIG11 is a schematic diagram of partial installation of the current collecting member and the protrusion in the embodiment shown in FIG10 ;

[0041] FIG12 is a schematic diagram showing the distribution of through holes on a current collecting member in one embodiment of a secondary battery disclosed herein;

[0042] FIG13 is a schematic diagram showing the distribution of through holes on a current collecting member in another embodiment of a secondary battery disclosed herein;

[0043] FIG14 is a three-dimensional schematic diagram of the corresponding arrangement of the through hole and the first recess in one embodiment of the secondary battery disclosed herein;

[0044] FIG15 is a schematic diagram of a partial structure of an end cap side in yet another embodiment of a secondary battery disclosed herein;

[0045] FIG16 is a partial enlarged view of the corresponding positions of the through hole and the first recess in the embodiment shown in FIG15 ;

[0046] FIG17 is a schematic diagram of the relative installation positions of the thickened portion and the convex portion in one embodiment of the secondary battery disclosed herein;

[0047] FIG18 is a partial enlarged view of the corresponding installation positions of the second concave portion and the convex portion in the embodiment shown in FIG17 ;

[0048] FIG19 is a schematic structural diagram of a current collecting member provided with a thickened portion in one embodiment of a secondary battery disclosed herein;

[0049] FIG20 is a three-dimensional schematic diagram of the corresponding arrangement of the first recess and the second recess in one embodiment of the secondary battery disclosed herein;

[0050] FIG21 is a schematic diagram of a partial structure of an end cap side of an embodiment of a secondary battery disclosed herein;

[0051] FIG22 is a partial enlarged view of corresponding positions of the first concave portion and the second concave portion in the embodiment shown in FIG21 ;

[0052] FIG23 is a schematic diagram of the overall structure of an embodiment of a battery pack disclosed herein;

[0053] FIG24 is a schematic diagram showing the structure of the battery pack of the present disclosure installed on a vehicle.

[0054] Component Reference Numerals 100, secondary battery; 110, housing; 111, end wall; 112, side wall; 1121, end face; 113, opening; 120, electrode assembly; 121, first tab; 122, second tab; 123, stacking gap; 130, current collecting member; 131, through hole; 132, thickened portion; 1321, second recess; 1322, inner circumferential surface of thickened portion; 1323, outer circumferential surface of thickened portion; 133, current collecting body; 140, end cap; 141, convex portion; 1411, first recess; 1412, inner circumferential surface of convex portion; 1 413. Outer peripheral surface of the convex portion; 142. Abutment area; 143. Cover body; 145. Liquid injection hole; 146. Extension portion; 147. Cover plate; 150. First gap; 160. Second gap; 170. Channel; 180. Explosion-proof valve; 190. Electrode terminal; 200. Battery pack; 210. Box body; 211. First box body portion; 212. Second box body portion; 300. Electronic device; 310. Working portion. DETAILED DESCRIPTION

[0055] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. The present disclosure can also be implemented or applied through other different specific embodiments, 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 disclosure. It should be noted that the following examples and the features in the examples can be combined with each other unless there is a conflict. It should also be understood that the terms used in the examples of the present disclosure are for the purpose of describing specific embodiments, not for the purpose of limiting the scope of protection of the present disclosure. The test methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under the conditions recommended by the manufacturers.

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

[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 disclosure. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present disclosure without substantially changing the technical content.

[0058] 1 to 24 , the present disclosure provides a secondary battery 100 , a battery pack 200 , and an electronic device 300 . The secondary battery 100 is configured with a channel 170 between the protrusion 141 of the end cap 140 and the electrode assembly 120 . This can improve the pressure relief and exhaust efficiency of the secondary battery 100 during thermal runaway, thereby improving the safety performance of the secondary battery 100 . Furthermore, the configuration of the channel 170 can also improve the liquid injection efficiency inside the secondary battery 100 , saving the time required for liquid injection and formation of the secondary battery 100 , thereby improving the production efficiency of the secondary battery 100 .

[0059] Please refer to Figures 1 and 3 for further description of the structure of the secondary battery 100, which includes a shell 110, an electrode assembly 120 and an end cap 140. A accommodating cavity is formed in the shell 110 for accommodating the electrode assembly 120, electrolyte and other components. The shell 110 can be open at one end or at both ends. The specific size of the shell 110 can 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 can 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, can be plated on the surface of the shell 110. Referring to FIG. 2 , in an example of a secondary battery 100 of the present disclosure, a 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 an opening 113 opposite the end wall 111 is an open end. The end wall 111 and the side wall 112 can be integrally formed or separately formed and then welded together.

[0060] As shown in Figure 2, the electrode assembly 120 is housed within the housing 110. The electrode assembly 120 is the component within the secondary battery 100 where the electrochemical reaction occurs. The housing 110 may contain one or more electrode assemblies 120. The electrode assembly 120 is primarily formed by winding or stacking positive and negative electrode sheets, with a separator typically provided between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer, which is coated on the surface of the positive electrode collector. The positive electrode collector includes a positive electrode coating region and a positive electrode tab connected to the positive electrode coating region. The positive electrode coating region is coated with the positive electrode active material layer, while the positive electrode tab is not coated with the positive electrode active material layer. The negative electrode sheet includes a negative electrode current collector and a negative active material layer, which is coated on the surface of the negative electrode collector. The negative electrode collector includes a negative electrode coating region and a negative electrode tab connected to the negative electrode coating region. The negative electrode coating region is coated with the negative electrode active material layer, while the negative electrode tab is not coated with the 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 a positive electrode active material. The positive electrode active material 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 a negative electrode active material. The negative electrode active material can be carbon or silicon. The main material of the separator can be PP or PE. 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] Referring to FIG. 2 , in an example of a secondary battery 100 of the present disclosure, an electrode assembly 120 is sealed and mounted within a housing 110 . A first electrode tab 121 and a second electrode tab 122 are provided at opposite ends of the lengthwise direction of the electrode assembly 120 . The first electrode tab 121 and the second electrode tab 122 have opposite polarities. The first electrode tab 121 faces the opening 113 of the housing 110 and is the negative electrode tab. It should be noted that in other embodiments, the first electrode tab 121 may be the positive electrode tab, and the second electrode tab 122 may be the negative electrode tab.

[0062] Of course, on the premise of meeting the conduction requirements between the electrode assembly 120 and the shell 110, in other embodiments of the secondary battery 100 disclosed herein, the first electrode tab 121 and the second electrode tab 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] Referring to Figure 2 , in one example of a secondary battery 100 of the present disclosure, a terminal mounting hole is formed through the end wall 111 of the housing 110. The electrode terminal 190 is sealed and insulated therein. The mounting method of the electrode terminal 190 on the end wall 111 is not limited, as long as the seal and insulation between the electrode terminal 190 and the end wall 111 are achieved. The electrode assembly 120 has a second electrode tab 122 on the side facing the end wall 111. One end of the electrode terminal 190 can be directly welded to the second electrode tab 122 or conductively connected to the second electrode tab 122 via a current collecting member, without specific limitation.

[0064] Referring to Figures 2 to 5 , in one example of the secondary battery 100 disclosed herein, an end cap 140 is disposed on the side of the opening 113 of the housing 110 . The outer edge of the end cap 140 is welded to the sidewall 112 of the housing 110 , ensuring a sealed connection between the end cap 140 and the opening 113 of the housing 110 . The structural form of the welded connection between the outer edge of the end cap 140 and the sidewall 112 of the housing 110 is not limited, as long as it meets the strength and sealing requirements of the welded connection between the housing 110 and the end cap 140 . The end cap 140 includes a cover 143 and a protrusion 141 circumferentially disposed around the outer periphery of the cover 143 . The protrusion 141 protrudes toward the electrode assembly 120 and supports the electrode assembly 120 . In this embodiment, the side of the protrusion 141 facing the electrode assembly 120 directly abuts against the first electrode tab 121 disposed on the end surface of the electrode assembly 120 , providing axial support for the electrode assembly 120 . It should be noted that during the use of the secondary battery 100, regardless of whether the end cap 140 side of the secondary battery 100 is placed facing up or facing down, as long as there is a direct or indirect abutment force between the protrusion 141 and the electrode assembly 120, in this disclosure, it can be interpreted that the protrusion 141 supports the electrode assembly 120. The protrusion 141 and the cover body 143 can be connected by an integral stamping process or fixed by welding, etc., as long as the performance of the end cap 140 can be guaranteed. Preferably, in this embodiment, the protrusion 141 and the cover body 143 are an integral stamping part. In this way, a higher molding efficiency of the end cap 140 can be achieved.

[0065] The protrusion 141 and the first electrode tab 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 protrusion 141 and the first electrode tab 121 are welded together, which can achieve more stable and reliable flow conduction performance between the end cap 140 and the electrode assembly 120. The protrusion 141 can be an annular structure coaxially arranged with the cover 143, or an annular structure not coaxially arranged with the cover 143, as long as the installation requirements of the end cap 140 are met. Preferably, in this embodiment, the protrusion 141 is a circular ring structure coaxially arranged with the cover 143. It should be noted that in another embodiment, the protrusion 141 and the first electrode tab 121 may not be welded, and a portion of the cover 143 may be recessed toward the electrode assembly 120 and abutted against the first electrode tab 121 before being welded. This can also achieve the flow conduction requirements between the end cap 140 and the electrode assembly 120.

[0066] Of course, in other embodiments of the secondary battery 100 of the present disclosure, as shown in Figures 6 to 8, a current collecting component 130 can also be provided between the end cover 140 and the electrode assembly 120, and the protrusion 141 can 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 present disclosure.

[0067] Referring to Figures 3 and 4 , the protrusion 141 includes a protrusion inner circumferential surface 1412 facing the axis of the housing 110. Within the inner region enclosed by the protrusion 141, a second gap 160 is formed between the cover 143, the protrusion inner circumferential surface 1412, and the electrode assembly 120. Within the housing 110, the region between the protrusion inner circumferential surface 1412 and the sidewall 112 of the housing 110 includes at least a first gap 150 formed between the electrode assembly 120 and the sidewall 112 of the housing 110, and an end face region of the electrode assembly 120 that abuts the protrusion 141. It should be noted that during the charge and discharge cycles of the secondary battery 100, as the electrode assembly 120 expands, the first gap 150 gradually decreases until it is no longer visible, while still allowing a small amount of gas to pass through. Furthermore, the end face region of the electrode assembly 120 that abuts the protrusion 141 typically defines a tab stacking gap that communicates with the tab gap within the electrode assembly 120.

[0068] A channel 170 is provided between the protrusion 141 and the electrode assembly 120. Channel 170 connects the inner region enclosed by the protrusion's inner circumferential surface 1412 and the region between the protrusion's inner circumferential surface 1412 and the sidewall 112. In this embodiment, the inner region enclosed by the protrusion's inner circumferential surface 1412 is the aforementioned second gap 160. In this embodiment, channel 170 connects the inner region enclosed by the protrusion's inner circumferential surface 1412 and the region between the protrusion's inner circumferential surface 1412 and the sidewall 112. This means that channel 170 can connect only the first gap 150 and the second gap 160, or only the second gap 160 and the end face region of the electrode assembly 120 abutting the protrusion 141. Alternatively, channel 170 can connect both the second gap 160 and the first gap 150, and also the second gap 160 and the end face region of the electrode assembly 120 abutting the protrusion 141.

[0069] It should be noted that in other embodiments of the secondary battery 100 disclosed herein, as shown in Figures 6 to 8 , when the protrusion 141 supports the electrode assembly 120 via the current collecting member 130, the second gap 160 is formed by the cover 143 located within the inner region of the protrusion 141, the protrusion inner circumferential surface 1412, and the current collecting member 130. The specific structure of the channel 170 is not limited. When the protrusion 141 abuts the electrode assembly 120, the channel 170 can be a through-slot structure provided on the protrusion 141; when the protrusion 141 abuts the electrode assembly 120 indirectly via 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-slot or through-hole structure provided on both the current collecting member 130 and the protrusion 141, as long as the inner region enclosed by the protrusion inner circumferential surface 1412 and the region between the protrusion inner circumferential surface 1412 and the sidewall 112 are 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, thereby realizing 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 electrode tab 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 electrode tab 121; on the other hand, it will also block the communication 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 present disclosure, by providing 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 in thermal 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 in the stacking gap 123 of the first electrode tab 121 can also quickly enter the second gap 160 through the channel 170, and then be quickly discharged from the explosion position. Therefore, it is possible to prevent gas from accumulating inside the first gap 150 or in the stacking gap 123 of the first electrode tab 121, causing lateral heat spread in the secondary battery 100, thereby ensuring that the secondary battery 100 can achieve directional pressure relief.

[0072] At the same time, since the provision of the channel 170 can increase the diffusion rate 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 electrode 121 can be quickly discharged through vacuuming, thereby improving the efficiency of vacuuming during the injection and formation process of the secondary battery 100, saving vacuuming time, and correspondingly increasing the injection and formation speed. On the other hand, when the secondary battery 100 is injected, the provision of the channel 170 can also accelerate the flow 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 electrode 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, setting a channel 170 between the protrusion 141 of the end cover 140 and the electrode assembly 120 can also reduce the 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] Referring to Figures 3 to 5 , in one example of the secondary battery 100 disclosed herein, the protrusion 141 further includes a protrusion outer peripheral surface 1413 on the side facing away from the axis of the housing 110. The protrusion outer peripheral surface 1413 can be coaxial with or non-coaxial with the protrusion inner peripheral surface 1412, as long as the protrusion outer peripheral surface 1413 forms a closed loop curved surface structure. Preferably, in this embodiment, the protrusion outer peripheral surface 1413 and the protrusion inner peripheral surface 1412 form a coaxial annular surface structure. The channel 170 includes a first recess 1411 formed on the side of the protrusion 141 facing the electrode assembly 120. The first recess 1411 is recessed in a direction away from the electrode assembly 120 and extends through the protrusion inner peripheral surface 1412 and the protrusion outer peripheral surface 1413. The first recess 1411 can be extended in a variety of ways. For example, the first recess 1411 can be extended in a curved shape, a straight line, or a spiral line, 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 disclosed herein, the first recess 1411 extends in the radial direction of the secondary battery 100. With this arrangement, 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, thereby making the airflow distribution in the circumferential direction more uniform, thereby helping to improve 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] Referring to Figures 6 to 8 , in an example of a secondary battery 100 disclosed herein, the secondary battery 100 further includes a current collecting member 130 . The current collecting member 130 is disposed within the housing 110 and is located on the side of the electrode assembly 120 facing the opening 113 . The current collecting member 130 is at least partially disposed in contact between the protrusion 141 and the electrode assembly 120 , and is electrically connected to the first electrode tab 121 . The electrical connection may be achieved by welding, adhesive bonding, or the like. Preferably, in this embodiment, the current collecting member 130 is welded to the first electrode tab 121 . The specific location and welding area of ​​the welded connection between the current collecting member 130 and the first electrode tab 121 are not limited, as long as a stable electrical connection between the current collecting member 130 and the first electrode 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 disclosure, as shown in Figures 6 to 8, under the premise that a 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 protrusion 141, so that the first recess 1411 can connect the inner area surrounded by the inner circumferential surface 1412 of the protrusion and the area between the inner circumferential surface 1412 of the protrusion and the side wall 112, that is, connect the first gap 150 and the second gap 160 in the above embodiment, or connect the second gap 160 in the above embodiment and the stacking gap 123 of the first electrode ear 121 at the position where the protrusion 141 abuts the current collecting component 120.

[0076] It should be noted that when the protrusion 141 abuts against the current collecting component 130, the current collecting component 130 will correspondingly compress the stacking gap 123 of the first pole tab 121 below. In this way, during the charging and discharging process of the secondary battery 100, when the gas generated by the electrode assembly 120 is exhausted toward the side of the first pole tab 121 along the gap between the pole pieces, at the corresponding position below the protrusion 141, since the end faces of the current collecting component 130 and the first pole tab 121 are pressed against each other, it will be 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 tab 121, as shown in Figure 11.

[0077] In view of this, in an example of the secondary battery 100 of the present disclosure, as shown in Figures 9 to 12 , a through hole 131 is further defined in the current collecting member 130. Through hole 131 extends through the current collecting member 130 along its thickness and is located at the outer periphery of the current collecting member 130. Along the height direction of through hole 131, the side of through hole 131 facing away from protrusion 141 communicates with the stacking gap 123 of the first electrode tab 121, while the side of through hole 131 facing protrusion 141 communicates with the second gap 160, thereby achieving interconnection between the stacking gap 123 of the first electrode tab 121 and the second gap 160 at the location where protrusion 141 abuts the current collecting member 120. The specific shape of through hole 131 is not limited and can be any through hole shape, such as a circular hole, an elongated hole, or a rectangular hole, that can connect the stacking gap 123 of the first electrode tab 121 with the second gap 160.

[0078] Referring to Figure 9 , in this embodiment, the current collecting member 130 is provided with a plurality of through holes 131, which are arranged around the outer periphery of the current collecting member 130. In other embodiments, a single through hole 131 may also be provided, without limitation. By providing the through holes 131 in the current collecting member 130, gas in the stacking gap 123 of the first electrode tab 121 can pass through the through holes 131 on the current collecting member 130 below the protrusion 141 and enter the interior of the second gap 160, thereby functioning as a channel 170. This improves the communication between the stacking gap 123 of the first electrode tab 121 and the second gap 160, specifically, the communication between the inner area enclosed by the protrusion inner circumference 1412 and the area between the protrusion inner circumference 1412 and the sidewall 112. The provision of the through holes 131 also reduces the weight of the current collecting member 130, thereby reducing the overall weight of the secondary battery 100 and improving its mass density.

[0079] Preferably, referring to FIG. 11 and FIG. 12 , in an example of the secondary battery 100 of the present disclosure, the through hole 131 is an elongated through hole 131 extending in the radial direction of the current collecting member 130 . With this arrangement, under the same area, the elongated through hole 131 extends longer in the radial direction of the current collecting component 130, thereby increasing the flow efficiency between the stacking gap 123 of the first pole ear 121 and the second gap 160, thereby further improving the flow efficiency of the gas between the stacking gap 123 of the first pole ear 121 and the second gap 160, and at the same time, further improving the gas discharge speed at the stacking gap 123 of the first pole ear 121 and the flow speed of the electrolyte between the stacking gap 123 of the first pole ear 121 and the second gap 160; in addition, the elongated through hole 131 extends shorter in the circumferential direction of the current collecting component 130, which can reduce the abutment area occupied between the protrusion 141 and the current collecting component 130, ensure the abutment and pressing effect, and help to improve the stability of the conductive connection between the current collecting component 130 and the end cover 140. It should be noted that in this embodiment, the current collecting member 130 is provided with a plurality of elongated through holes 131, and the plurality of elongated through holes 131 are arranged in an array along the center of the current collecting member 130 and on the outer periphery of the current collecting member 130. This arrangement enables the stacking gap 123 of the first electrode tab 121 to achieve a more uniform exhaust effect in the circumferential direction.

[0080] To further increase the flow rate of gas or electrolyte within the housing 110 through the through-hole 131, as shown in FIG13 , in this embodiment, the through-hole 131 extends radially through the outer edge of the current collecting member 130. This configuration forms a through-opening on the side of the through-hole 131 facing the first gap 150. This through-opening not only increases the radially connected area between the stacking gap 123 of the first tab 121 and the second gap 160, but also connects the first gap 150 with the second gap 150, allowing gas in the first gap 150 to be discharged into the second gap 160 through the through-hole 131. This configuration further increases the rate at which gas in the stacking gap 123 of the first tab 121 is discharged into the second gap 160 through the through-hole 131. It also increases the rate at which gas in the first gap 150 is discharged into the second gap 160, thereby further enhancing the venting and pressure relief of the secondary battery 100 in the event of thermal runaway.

[0081] Referring to Figures 10 and 11 , in one example of the secondary battery 100 of the present disclosure, an abutment region 142 is formed between the protrusion 141 and the current collecting member 130. At least a portion of the through-hole 131 extends into the abutment region 142, and at least another portion of the through-hole 131 extends radially inward of the protrusion 141. The portion of the through-hole 131 located in the abutment region 142 communicates with the stacking gap 123 of the first electrode tab 121, while the portion of the through-hole 131 extending radially inward of the protrusion 141 communicates with the second gap 160, thereby achieving communication between the stacking gap 123 of the first electrode tab 121 at the location of the abutment region 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 part 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 contact area 142 between the protrusion 141 and the current collecting member 130, the better the contact and compression effect on the current collecting member 130, but correspondingly, the less conducive it is to the outward diffusion of gas in the first gap 150; conversely, the gas diffusion effect is better and the compression effect is worse. Preferably, referring to Figure 11, in an example of the secondary battery 100 disclosed herein, 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 contact area 142 along the radial direction of the secondary battery 100. This arrangement can not only achieve a better exhaust speed between the stacking gap 123 of the first electrode 121 and the through hole 131, but also ensure the contact area between the protrusion 141 and the current collecting member 130, thereby ensuring the stability of the electrical connection of the current collecting member 130.

[0083] In another embodiment of the present disclosure, in addition to the through-hole 131 of the above-described embodiment, the protrusion 141 is further provided with a first recess 1411 of the above-described embodiment, as shown in Figures 14 to 16 . The positional relationship between the first recess 1411 and the through-hole 131 is not limited. For example, the first recess 1411 can partially overlap with the through-hole 131, or can be spaced apart from each other along the circumferential direction of the end current collecting component 130. Such an arrangement allows the gas in the first gap 150 and the gas in the stacking gap 123 of the first electrode tab 121 to partially enter the second gap 160 through the first recess 1411 and partially enter the second gap 160 through the through hole 131, thereby forming more connecting channels 170 between the second gap 160 and the stacking gap 123 of the first electrode tab 121, and between the second gap 160 and the first gap 150, thereby further improving the gas circulation efficiency and the electrolyte circulation speed between the second gap 160 and the first gap 150, and between the second gap 160 and the stacking gap 123 of the first electrode tab 121.

[0084] Further, referring to Figures 14 to 16 , in one example of the secondary battery 100 disclosed herein, at least some of the multiple through-holes 131 defined on the outer periphery of the current collecting member 130 correspond to the first recesses 1411. This correspondence means that, along the thickness direction of the end cap 140, an overlap is formed between the orthographic projection of the first recess 1411 on the current collecting member 130 and the through-holes 131. This allows the combination of the first recess 1411 and the through-holes 131 to connect the second gap 160 with the first gap 150, and the second gap 160 with the stacking gap 123 of the first electrode tab 121. The specific size of the overlap is not limited; preferably, in this embodiment, the orthographic projection of the first recess 1411 on the current collecting member 130 completely covers the circumferential width of the through-holes 131. This arrangement creates a larger channel 170 between the protrusion 141 and the current collecting member 130, allowing gas or electrolyte within the housing 110 to circulate 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. This further improves the flow rate of gas or electrolyte within the housing 110. It should be noted that the number of first recesses 1411 and through-holes 131 can be equal or unequal, as long as the orthographic projections of some through-holes 131 and the first recesses 1411 on the current collecting member 130 overlap.

[0085] Referring to Figures 17 to 19 , in one example of a secondary battery 100 disclosed herein, the current collecting member 130 includes a current collecting body 133 and a thickened portion 132 disposed on the side of the current collecting body 133 facing the protrusion 141. The thickened portion 132 is located on the outer periphery of the current collecting body 133 and abuts the side of the protrusion 141 facing the electrode assembly 120. The thickened portion 132 can be a circular ring structure coaxially disposed with the protrusion 141, or a ring structure of another shape that is not coaxially disposed with the protrusion 141, as long as an annular abutment area is formed between the protrusion 141 and the thickened portion 132. Preferably, in this embodiment, the thickened portion 132 is coaxially disposed with the protrusion 141. This facilitates positioning of the thickened portion 132 and the protrusion 141 and also provides a better abutment area. The thickened portion 132 and the current collecting body 133 can be connected by an integral molding process or by any other connection method, such as welding. Preferably, in this embodiment, the thickened portion 132 is welded to the current collecting body 133, which facilitates the processing and forming of the current collecting member 130. By providing the thickened portion 132 on the current collecting member 130 and welding the thickened portion 132 to the protrusion 141 in contact therewith, the probability of welding through the current collecting member 130 can be reduced when welding the protrusion 141 to the current collecting member 130 from the end cap 140 side, thereby increasing the welding process window between the end cap 140 and the current collecting member 130. Furthermore, while ensuring satisfactory welding quality, the welding efficiency between the end cap 140 and the current collecting member 130 can be correspondingly improved.

[0086] Further, please continue to refer to Figures 17 to 19. In one embodiment of the present disclosure, 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. The thickened portion 132 is further provided with a second recessed portion 1321, which is recessed toward the side facing away from the convex portion 141 and extends through the thickened portion inner circumferential surface 1322 and the thickened portion outer circumferential surface 1323. The second recessed portion 1321 can extend in various ways, for example, the second recessed portion 1321 can extend in a curved shape, a straight line, a spiral line, or any other extension that can laterally extend through 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 within the housing 110 can flow through the second recess 1321 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. This improves the efficiency of the flow of gas or electrolyte within 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 electrode tab 121. Furthermore, providing the second recess 1321 on the thickened portion 132 also reduces the weight of the current collecting member 130, thereby reducing the overall weight of the secondary battery 100 and improving its mass density.

[0087] It should be noted that in some embodiments of the present disclosure, as shown in Figures 17 and 18, 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 component 130. In this way, the communication between the first gap 150 and the second gap 160, and the second gap 160 and the stacking gap 123 of the first electrode tab 121 can be fully achieved only through the second recess 1321, thereby improving the circulation 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 electrode tab 121.

[0088] In some other embodiments of the present disclosure, as shown in Figures 20 and 22, in addition to the first recess 1411 in the above-mentioned embodiment provided on the convex portion 141, a second recess 1321 is also provided on the thickened portion 132. With this arrangement, the gas or electrolyte in the housing 110 can not only 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 electrode tab 121 through the first recess 1411, but 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 electrode tab 121 through the second recess 1321. Therefore, the flow of 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 electrode tab 121 can be further improved.

[0089] Preferably, in an example of the secondary battery 100 disclosed herein, the second recess 1321 extends in the radial direction of the secondary battery 100. This configuration reduces the flow resistance generated by the gas or electrolyte in the housing 110 when flowing through the second recess 1321, thereby increasing the flow rate 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 tab 121.

[0090] 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 tab 121, further referring to Figures 20 to 22, in one example of the secondary battery 100 disclosed herein, the second recess 1321 and the first recess 1411 provided on the thickened portion 132 are at least partially arranged to correspond to each other. "Corresponding arrangement" means that, along the thickness direction of the end cap 140, an overlap 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, thereby allowing the first recess 1411 and the second recess 1321 to connect the first gap 150 and the second gap 160. The specific size of the overlap is not limited; preferably, in this embodiment, the orthographic projection of the first recess 1411 on the current collecting member 130 completely covers the circumferential width of the second recess 1321. This arrangement creates a larger channel 170 between the protrusion 141 and the current collecting member 130, allowing gas or electrolyte within the housing 110 to circulate 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. This further improves the flow rate of gas or electrolyte within the housing 110. It should be noted that the number of first recesses 1411 and second recesses 1321 can be equal or unequal, as long as the orthographic projections of some second recesses 1321 and first recesses 1411 on the current collecting member 130 overlap.

[0091] To facilitate the welding connection between end cap 140 and side wall 112, in one example of the secondary battery 100 of the present disclosure, as shown in Figures 4 and 7, end cap 140 further includes an extension portion 146. Extension portion 146 is disposed around the outer periphery of protrusion 141 and extends outward along the circumferential outer edge of end cap 140. The outer diameter of extension portion 146 is greater than the inner diameter of side wall 112 of housing 110 at the location of opening 113. Side wall 112 includes an end surface 1121 on one side of opening 113. When end cap 140 is installed at opening 113 of housing 110, extension portion 146 overlaps end surface 1121 and is fixedly connected to end surface 1121 by welding, thereby achieving a sealed weld between end cap 140 and housing 110. Since the convex portion 141 is provided on the radial inner side of the extension portion 146, on the one hand, the convex portion 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 convex portion 141, thereby forming a welding fixing point between the side wall 112 and the convex portion 141, further improving the sealing performance and connection strength between the side wall 112 and the end cover 140.

[0092] Furthermore, in an example of the secondary battery 100 disclosed herein, as shown in FIG4 , along the thickness direction of the end cap 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, while at the same time making the second gap 160 have a better height, ensuring the gas storage space of the second gap 160, and meeting the normal pressure relief requirements of the secondary battery 100.

[0093] Referring to Figures 3 and 6 , in one example of the secondary battery 100 of the present disclosure, the secondary battery 100 further includes an explosion-proof valve 180, which is disposed on the end cap 140 and located on the side of the protrusion 141 near the center of the electrode assembly 120. The explosion-proof valve 180 can be any explosion-proof structure, such as an explosion-proof notch or an explosion-proof valve plate. 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 within the inner region enclosed by the protrusion 141. Therefore, 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 first discharged from the rupture. 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] Referring to Figures 3 and 5 , in one example of the secondary battery 100 disclosed herein, an injection hole 145 is further provided on the end cap 140, and the injection hole 145 is located within the inner area enclosed by the protrusion 141. The injection hole 145 can be located in the center area of ​​the end cap 140 or offset from the center area, without specific limitation, as long as the injection requirements of the injection hole 145 are met. Preferably, in this embodiment, the injection hole 145 is a circular hole structure coaxially arranged with the end cap 140. This arrangement not only facilitates positioning of the injection device and the injection hole 145, but also allows the injection hole 145 to align with the center hole of the electrode assembly 120, thereby improving the injection efficiency of the secondary battery 100. To seal the injection hole 145 on the end cap 140, in this embodiment, the secondary battery 100 further includes a cover plate 147, which is mounted on the end cap 140 to seal the injection hole 145. There is no limit to the way the cover plate 147 covers the injection hole 145. For example, the cover plate 147 can be bonded to the injection hole 145, or it can be snapped onto the injection hole 145 by interference fit, or it can be sealed to the injection hole 145 by sealing welding, as long as the sealing requirements of the injection hole 145 are met.

[0095] It should be noted that the liquid injection hole 145 in the above embodiment may be provided on the end wall 111 side of the housing 110 instead of on the end cap 140. This arrangement can also serve to inject liquid into the interior of the electrode assembly 120. When the liquid injection hole 145 is provided on the end wall 111 side, the liquid injection hole 145 may be provided on the electrode terminal 190 or on the end wall 111, and this is not limited to this.

[0096] Referring to Figure 23 , in one embodiment of a battery pack 200 disclosed herein, the battery pack 200 includes a housing 210 and at least one secondary battery 100. The housing 210 includes a first housing portion 211 and a second housing portion 212. The first housing portion 211 and the second housing portion 212 overlap to form a housing space within which multiple secondary batteries 100 are housed. 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, or the like.

[0097] Referring to Figure 24 , an example of an electronic device 300 disclosed herein includes a working unit 310 and a battery pack 200 . The working unit 310 is electrically connected to the battery pack 200 to obtain electrical energy. The working unit 310 may be a unit component capable of absorbing electrical energy from the battery pack 200 and performing corresponding operations, such as a fan blade rotation unit, a vacuum cleaner suction unit, or a wheel drive unit in an electric vehicle. The electronic device 300 may include a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. Vehicles can be fuel vehicles, gas vehicles or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid vehicles or extended-range vehicles, etc.; spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers, etc. The embodiment of the present disclosure does not impose any special restrictions on the above-mentioned electronic device 300. In one embodiment of the electronic device 300 of the present disclosure, 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 secondary battery disclosed herein provides a channel between the protrusion and the electrode assembly, connecting the channel to the inner region enclosed by the inner circumference of the protrusion and the region between the inner circumference of the protrusion and the sidewall. This arrangement, on the one hand, can accelerate the flow of gas within the inner region enclosed by the inner circumference of the protrusion and the region between the inner circumference of the protrusion and the sidewall. When the secondary battery experiences thermal runaway, the gas generated in the region between the inner circumference of the protrusion and the sidewall can quickly enter the inner region and be discharged from the explosion location, thereby preventing the secondary battery from experiencing lateral heat spread and causing more serious consequences. Furthermore, when the secondary battery is being filled and vacuumed during formation, the gas in the region between the inner circumference of the protrusion and the sidewall can quickly flow into the inner region enclosed by the inner circumference of the protrusion through the channel. This can not only accelerate the exhaust speed of the secondary battery and save vacuuming time, but also prevent gas from being trapped inside the housing, ensuring the vacuuming effect, thereby ensuring the effectiveness of the filling and formation. Furthermore, when the secondary battery is being filled, the provision of the channel can also accelerate the flow of electrolyte within the housing, thereby effectively improving the filling efficiency of the secondary battery. Therefore, the present disclosure effectively overcomes some practical problems in the prior art and thus has high utilization value and practical significance. The above embodiments are merely illustrative of the principles and effects of the present disclosure and are not intended to limit the present disclosure. Anyone familiar with the technology may modify or change the above embodiments without departing from the spirit and scope of the present disclosure. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the art without departing from the spirit and technical ideas disclosed in the present disclosure shall still be covered by the claims of the present disclosure.

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 a 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 protrusion on one side thereof facing the protrusion.

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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