A cylindrical battery, a battery pack, and an electronic device

Abstract

This invention provides a cylindrical battery, a battery pack, and an electronic device. The cylindrical battery includes a cover plate, a housing, an electrode assembly, and a current collector. The housing includes a sidewall with at least one opening, and the cover plate seals at least one opening. The electrode assembly is housed within the housing and has tabs. The current collector is disposed on the side of the electrode assembly facing the cover plate and includes a first connecting portion and a plurality of second connecting portions. The first connecting portion is welded to the tabs, and the plurality of second connecting portions are spaced apart around the outer periphery of the first connecting portion. The cover plate connects the second connecting portions and the sidewall through a plurality of first arc-shaped weld marks, and the cover plate connects the sidewall through a plurality of second arc-shaped weld marks. The ratio of the arc length L of each first arc-shaped weld mark to the circumference C of the sidewall satisfies: 0.07 ≤ L / C ≤ 0.333. This invention can improve the technical problem of low welding yield when laser sealing cylindrical batteries.

Description

Technical Field

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

[0002] Laser sealing welding technology is currently the mainstream negative electrode electrical connection method for cylindrical batteries. Specifically, a cover plate is placed over the opening of the casing, and the cover plate is sealed and fixed to the casing by laser welding. At the same time, a reliable welded connection is formed between the cover plate, the current collector, and the casing to achieve electrical connection between the current collector and the cover plate.

[0003] In existing technologies, when performing laser sealing welding, welding defects such as incomplete welding and welding deviation often occur during the welding process, resulting in a low welding yield between the cover plate and the side wall. Utility Model Content

[0004] This invention provides a cylindrical battery, a battery pack, and an electronic device to improve the technical problem of low welding yield when laser sealing cylindrical batteries are subjected to welding.

[0005] The first aspect of this utility model provides a cylindrical battery, which includes: a cover plate, a housing, an electrode assembly, and a current collector; the housing includes a sidewall with at least one opening, and the cover plate seals at least one opening; the electrode assembly is housed within the housing, and the electrode assembly has a tab on the side facing the opening; the current collector is disposed on the side of the electrode assembly facing the cover plate, and includes a first connecting portion and a plurality of second connecting portions, the first connecting portion being welded to the tab, and the plurality of second connecting portions being spaced apart around the outer periphery of the first connecting portion; wherein, the cover plate connects the second connecting portions and the sidewall through a plurality of first arc-shaped weld marks, and the cover plate connects the sidewall through a plurality of second arc-shaped weld marks, and the ratio of the arc length L of each first arc-shaped weld mark to the perimeter C of the sidewall satisfies: 0.07≤L / C≤0.333.

[0006] In one embodiment of the present invention, the ratio of the arc length L of the first arc-shaped solder mark to the perimeter C of the sidewall satisfies: 0.1≤L / C≤0.2.

[0007] In one embodiment of the present invention, a sidewall is disposed around the outer periphery of the cover plate, and at least a portion of the second connecting portion extends axially along the housing and is sandwiched between the sidewall and the cover plate.

[0008] In one embodiment of the present invention, the weld width of the first arc-shaped weld is T1, the weld width of the second arc-shaped weld is T2, and T1 > T2; and / or, the weld depth of the first arc-shaped weld is H1, the weld depth of the second arc-shaped weld is H2, H1 > H2, and the thickness of the second connection is T3, 1.1 × T3 < T1 < 2.67 × T3.

[0009] In one embodiment of the present invention, the outer periphery of the cover plate is provided with a plurality of grooves in the circumferential direction. Along the axial direction of the housing, the grooves include groove openings facing the outer side of the cover plate. The second connecting portion is accommodated in the grooves and is at least partially exposed to the groove openings. The protrusions formed between the plurality of grooves abut against the inner wall of the sidewall to form the second arc-shaped weld mark.

[0010] In one embodiment of the present invention, the sidewall near the opening includes a first end face, and the outer periphery of the cover plate overlaps the first end face; at least a portion of the second connecting portion extends radially along the housing and is sandwiched between the sidewall and the cover plate.

[0011] In one embodiment of the present invention, the sidewall near the opening is provided with a plurality of grooves in the circumferential direction, the groove openings are opposite to the other end of the sidewall, and the grooves penetrate the sidewall radially along the housing, the second connecting part is accommodated in the groove, the cover plate covers the groove opening and presses the second connecting part into the groove.

[0012] In one embodiment of the present invention, the second connecting portion includes a straight section and a connecting section. The straight section is connected to the first connecting portion through the connecting section and extends into the groove along the radial direction of the housing. The included angle between the connecting section and the straight section is less than 180°. The cover plate has a positioning surface on the side facing the electrode assembly. The positioning surface presses against the connecting section to press the straight section into a predetermined position within the groove.

[0013] A second aspect of this invention provides a battery pack comprising the cylindrical battery described in any of the above embodiments.

[0014] A third aspect of this invention provides an electronic device that includes the battery pack described in the above embodiments.

[0015] The beneficial effects of this utility model are as follows: The cover plate is connected to the second connecting part and the side wall through multiple first arc-shaped weld marks, achieving triple sealing welding between the cover plate, the current collection component, and the side wall; the cover plate is also connected to the side wall through multiple second arc-shaped weld marks, achieving double sealing welding between the cover plate and the side wall. This design allows for triple welding only in localized areas along the circumference of the cover plate, while only double welding is required in other areas. Through the above design, multiple spaced first and second arc-shaped weld marks are formed along the circumference of the cover plate, decomposing the traditional continuous circumferential welding into multiple independent arc-shaped welding segments. Each arc-shaped weld mark (including the first and second arc-shaped weld marks) can be independently positioned and calibrated during the welding process, thereby effectively compensating for the deviation between the welding position and the predetermined laser welding trajectory between the cover plate and the side wall caused by the roundness error of the shell opening. Compared to continuous welding around the entire circle, this segmented welding stamp design can reduce the maximum trajectory deviation within the single arc length welding stamp range, thereby improving the welding position accuracy, reducing missed welds or weld deviations during the welding process, and thus ensuring the welding quality between the cover plate and the side wall, and improving the welding yield when laser sealing welding is performed at the opening position of the shell. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0017] In the attached diagram:

[0018] Figure 1 This is a schematic diagram of the overall three-dimensional structure of a cylindrical battery provided in an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the electrode assembly in a cylindrical battery provided in one embodiment of the present invention;

[0020] Figure 3 for Figure 1 Top view of the embodiment shown;

[0021] Figure 4 for Figure 3 A cross-sectional view along the AA direction;

[0022] Figure 5 for Figure 4 A magnified view of a portion of region C in the middle;

[0023] Figure 6 middle Figure 4 A partial cross-sectional view of the first arc-shaped solder mark location in the illustrated embodiment;

[0024] Figure 7 for Figure 3 Cross-sectional view along the BB direction;

[0025] Figure 8 for Figure 7 A magnified view of a portion of region D in the middle;

[0026] Figure 9 middle Figure 1 The embodiment shown is a schematic diagram of the structure without the current collection component;

[0027] Figure 10 for Figure 9 A magnified view of a portion of region E in the middle;

[0028] Figure 11 This is a schematic diagram of a cover plate with a groove and a protrusion on its outer periphery in one embodiment of the present invention;

[0029] Figure 12 for Figure 11 Top view of the cover plate shown;

[0030] Figure 13 This is a schematic diagram of the structure in which the second connecting part is installed in the groove in one embodiment of the present invention;

[0031] Figure 14 for Figure 13 The diagram shows the installation position of the current collection component inside the housing after removing the cover plate in the embodiment shown.

[0032] Figure 15 for Figure 14 A magnified view of a portion of region X in the middle;

[0033] Figure 16 This is a schematic diagram of the structure in which the second connecting part is installed in the groove on the side wall in one embodiment of the present invention;

[0034] Figure 17 for Figure 16 Enlarged view of the partial installation position between the second connecting part, the side wall, and the cover plate when the groove is provided on the side wall in the embodiment shown;

[0035] Figure 18 for Figure 16 A three-dimensional structural diagram of the embodiment shown, in which grooves are provided on the sidewalls;

[0036] Figure 19 for Figure 16 A partial structural diagram showing a groove on the sidewall in the illustrated embodiment;

[0037] Figure 20 This is a schematic diagram of the connection structure of the cover plate, side wall and flow collection component in one embodiment of the present invention;

[0038] Figure 21 for Figure 20 A magnified view of a portion of region G in the middle;

[0039] Figure 22 for Figure 20 Enlarged view of region H in the middle

[0040] Figure 23 This is a schematic diagram of a pre-fabricated solder portion provided on the groove of the side wall in one embodiment of the present invention;

[0041] Figure 24 for Figure 16 A schematic diagram of the overall structure of the current collection component in the embodiment shown;

[0042] Figure 25 for Figure 24 A magnified view of a portion of region I;

[0043] Figure 26 This is a schematic diagram showing the position of the pre-installed solder part when the cover body has a groove in one embodiment of the present invention;

[0044] Figure 27 This is a schematic diagram of the installation structure between the cover, the second connecting part, and the side wall when the cover is provided with a groove in one embodiment of the present invention.

[0045] Figure 28 for Figure 27 A magnified view of a portion of region J in the middle;

[0046] Figure 29 for Figure 27 A schematic diagram of the cover plate structure in the illustrated embodiment;

[0047] Figure 30 for Figure 29 A magnified view of a portion of the K region;

[0048] Figure 31 This is a schematic diagram of the connection structure of the cover plate, side wall and flow collection component in another embodiment of the present invention;

[0049] Figure 32 for Figure 31 A partial schematic diagram of the cover plate, side wall and current collection component welded together to form a first arc-shaped weld mark in the embodiment shown;

[0050] Figure 33 for Figure 31 A partial schematic diagram of the embodiment shown, showing the second arc-shaped weld mark formed by welding the cover plate and sidewall;

[0051] Figure 34 for Figure 31 The diagram shown is a schematic of the structure after removing the cover plate in the embodiment shown.

[0052] Figure 35 This is a schematic diagram of the connection structure of the cover plate, side wall and flow collection component in another embodiment of the present invention;

[0053] Figure 36 for Figure 35 A partial schematic diagram of the cover plate, side wall and current collection component welded together to form a first arc-shaped weld mark in the embodiment shown;

[0054] Figure 37 for Figure 35 A partial schematic diagram of the embodiment shown, showing the second arc-shaped weld mark formed by welding the cover plate and sidewall;

[0055] Figure 38 for Figure 35 The diagram shown is a schematic of the structure after removing the cover plate in the embodiment shown.

[0056] Figure 39 This is a schematic diagram of the welding structure between the sidewall, the flow collecting component, and the cover plate in another embodiment of the present invention;

[0057] Figure 40 for Figure 39 A partially enlarged schematic diagram of the first arc-shaped solder mark location in the illustrated embodiment;

[0058] Figure 41 for Figure 39 A partially enlarged schematic diagram of the second arc-shaped solder mark location in the illustrated embodiment;

[0059] Figure 42 for Figure 39 The diagram shows a schematic of the second connecting part being disposed in the groove in the embodiment shown.

[0060] Figure 43 for Figure 42 A schematic diagram of the groove after removing the second connecting part in the embodiment shown;

[0061] Figure 44 for Figure 42 The diagram shown is a schematic of the structure after removing the cover plate in the embodiment shown.

[0062] Figure 45 for Figure 42 The diagram shown illustrates a structure in which the housing has a groove.

[0063] Figure 46 for Figure 39 A partially enlarged schematic diagram of the mounting position between the cover, the second connecting part, and the side wall in the embodiment shown;

[0064] Figure 47 for Figure 42 A magnified view of a portion of region L in the middle;

[0065] Figure 48 for Figure 42 A magnified view of a portion of region M in the middle;

[0066] Figure 49 This is a schematic diagram of an example of the battery pack of this utility model;

[0067] Figure 50 This is a schematic diagram of an example of the electronic device of this utility model.

[0068] The attached figures are labeled as follows:

[0069] 100. Cylindrical battery; 110. Casing; 111. Side wall; 112. Opening; 113. Stepped portion; 1131. Support surface; 1132. Stepped side wall; 114. End wall; 115. Electrode terminal; 116. Support end face; 120. Electrode assembly; 121. Positive electrode; 1211. Positive current collector; 1212. First coated area; 1213. First uncoated area; 122. Separator; 123. Negative electrode; 1231. Negative current collector; 1232. Second coated area; 1233. Second uncoated area; 124. Negative electrode tab; 125. Positive electrode tab; 130. Current collector component; 131. First connecting portion; 132. Second connecting portion; 1321. Bending section; 1322. Extension section; 1323. Flat section; 1324. Straight section; 1325. Connecting section; 140. Second end face; 141. Cover plate; 142. Body part; 142. Deformable part; 1421. First annular wall; 1422. Second annular wall; 1423. Top wall; 143. Third connecting part; 1431. First end face; 144. Annular recess; 145. Annular protrusion; 146. Protrusion; 147. Annular groove; 1471. Annular bottom wall; 1472. Annular side wall; 151. First arc-shaped weld mark; 152. Second arc-shaped weld mark; 160. Groove; 161. Groove opening; 162. Pre-made solder part; 163. Assembly gap; 200. Battery pack; 210. Housing; 211. First housing part; 212. Second housing part; 300. Electronic device; 310. Working part. Detailed Implementation

[0070] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0071] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0072] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention.

[0073] Please see Figures 1 to 50 This invention provides a cylindrical battery 100, a battery pack 200, and an electronic device 300. The cylindrical battery 100 achieves welding of the cover plate 140, current collector 130, and sidewall 111 by providing multiple spaced-apart second connecting portions 132 on the current collector 130, and by connecting the second connecting portions 132 and the sidewall 111 with multiple first arc-shaped weld marks 151. The cover plate 140 also achieves welding of the cover plate 140 and the sidewall 111 by connecting the sidewall 111 with multiple second arc-shaped weld marks 152. Thus, during laser sealing welding, multiple spaced-apart first arc-shaped weld marks 151 and second arc-shaped weld marks 152 can be formed along the circumference of the cover plate 140. Compared to the full-circle welding method of the current collector 130, this welding method significantly reduces the input of welding heat, thereby reducing thermal damage to the internal electrode assembly 120 of the cylindrical battery 100 and improving the safety performance of the cylindrical battery 100.

[0074] In this invention, the cylindrical battery 100 may include lithium-ion batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this invention are not limited to this.

[0075] Please see Figure 1 and Figure 4 The structure of the cylindrical battery 100 is further described, which includes: a cover plate 140, a housing 110, an electrode assembly 120, and a current collector 130.

[0076] Please see Figure 4The housing 110 includes a surrounding sidewall 111, with at least one opening 112 at one end of the sidewall 111, and a cover plate 140 sealing the at least one opening 112. The sidewall 111 may have an opening 112 at one end, with the cover plate 140 sealing the opening 112. Alternatively, the sidewall 111 may have openings 112 at both ends, with two corresponding cover plates 140, each sealing one of the openings 112. Optionally, in this embodiment, one end of the sidewall 111 has an opening 112, which is sealed by the cover plate 140. The other end of the sidewall 111 has an end wall 114, and the housing 110 formed by the end wall 114 and the sidewall 111 has a receiving cavity for accommodating the electrode assembly 120, electrolyte, and other necessary battery components. In one example, the end wall 114 has mounting holes for electrode terminals 115.

[0077] Please see Figure 2 and Figure 4 An electrode assembly 120 is disposed inside the housing 110 and has tabs on the side of the electrode assembly 120 facing the opening 112. The electrode assembly 120 is a component in the cylindrical battery 100 where an electrochemical reaction occurs. The housing 110 may contain one or more electrode assemblies 120. Exemplarily, in this embodiment, one electrode assembly 120 is disposed inside the housing 110. The electrode assembly 120 includes an electrode sheet and a separator 122, which are wound to form a wound structure. Specifically, in this embodiment, the electrode assembly 120 includes a positive electrode sheet 121, a separator 122, and a negative electrode sheet 123 wound around the axial direction of the housing 110.

[0078] Please see Figure 2 The positive electrode 121 includes a positive current collector 1211 and a positive active material layer coated on the positive current collector 1211. A first coated area 1212 coated with the positive active material layer and a first uncoated area 1213 uncoated with the positive active material layer are formed on the positive current collector 1211. The first coated area 1212 and the first uncoated area 1213 are arranged along the axial direction of the housing 110. The first uncoated area 1213 extends to one end of the cylindrical battery 100 in the height direction to the outside of the separator 122 and is bent towards the axis of the housing 110 to form a stacked positive electrode tab 125.

[0079] The negative electrode 123 includes a negative current collector 1231 and a negative active material layer coated on the negative current collector 1231. A second coated area 1232 coated with the negative active material layer and a second uncoated area 1233 uncoated with the negative active material layer are formed on the negative current collector 1231. The second coated area 1232 and the second uncoated area 1233 are arranged along the axial direction of the housing 110. The second uncoated area 1233 extends to the other end of the cylindrical battery 100 in the height direction to the outside of the separator 122 and is bent towards the axis of the housing 110 to form a stacked negative electrode tab 124.

[0080] A separator 122 is disposed between the positive electrode 121 and the negative electrode 123 to isolate the positive and negative active material layers. Taking a lithium-ion cylindrical battery 100 as an example, the positive current collector 1211 can be made of aluminum, and the positive active material layer includes positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative current collector 1231 can be made of copper, and the negative active material layer includes negative active material, which can be carbon or silicon, etc. The substrate material of the separator 122 can be polypropylene (PP) or polyethylene (PE), etc. To protect and insulate the electrode assembly 120, an insulating film can also be wrapped around the electrode assembly 120. The insulating film can be synthesized from PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other polymer materials.

[0081] Please see Figure 4 In this invention, the tab on the side of the electrode assembly 120 facing the opening 112 is a negative tab 124, and the cover plate 140 is electrically connected to the negative tab 124, thus carrying a negative charge. The tab on the side of the electrode assembly 120 facing the end wall 114 is a positive tab 125, and the positive tab 125 is electrically connected to the electrode terminal 115 disposed on the end wall 114, so that the electrode terminal 115 carries a positive charge. Of course, in other embodiments, the tab on the side of the electrode assembly 120 facing the opening 112 can be a positive tab 125, and the cover plate 140 can be electrically connected to the positive tab 125, thus carrying a positive charge. The tab on the side of the electrode assembly 120 facing the end wall 114 can be a negative tab 124, and the negative tab 124 is electrically connected to the electrode terminal 115 disposed on the end wall 114, so that the electrode terminal 115 carries a negative charge.

[0082] Please see Figure 5 and Figure 14 The current collector 130 is disposed on the side of the electrode assembly 120 facing the cover plate 140, and includes a first connecting portion 131 and a plurality of second connecting portions 132. The first connecting portion 131 is welded to the electrode tab, and the plurality of second connecting portions 132 are spaced apart around the outer periphery of the first connecting portion 131. Specifically, in this embodiment, the first connecting portion 131 is welded to the negative electrode tab 124. The number of second connecting portions 132 is not limited, for example, there can be two, three or more. One end of the second connecting portion 132 is connected to the outer edge of the first connecting portion 131, and the other end extends toward the cover plate 140.

[0083] Please see Figure 3 , Figure 6 and Figure 8 Along the circumferential direction of the cover plate 140, there are multiple areas where the second connecting parts 132, the cover plate 140, and the side wall 111 are close to each other, and multiple areas where the cover plate 140 and the side wall 111 are close to each other. It can be understood that in the circumferential direction of the housing 110, the area where the flow collecting member 130 is provided with the second connecting parts 132 will form a three-way close-to-each-other area with the cover plate 140 and the side wall 111, while in the area where the flow collecting member 130 is not provided with the second connecting parts 132, that is, the area where the flow collecting member 130 is located between two adjacent second connecting parts 132, the cover plate 140 is directly close to the side wall 111, forming a two-way close-to-each-other area. In the region where the second connecting part 132, the cover plate 140, and the side wall 111 are close to each other, the cover plate 140 is connected to the second connecting part 132 and the side wall 111 by multiple first arc-shaped weld marks 151, that is, the first arc-shaped weld marks 151 can achieve triple welding between the cover plate 140, the second connecting part 132, and the side wall 111. In the region where the cover plate 140 and the side wall 111 are close to each other, the cover plate 140 is connected to the side wall 111 by multiple second arc-shaped weld marks 152, that is, the second arc-shaped weld marks 152 can achieve double welding between the cover plate 140 and the side wall 111. The ratio of the arc length L of each first arc-shaped weld mark 151 to the perimeter C of the side wall 111 satisfies: 0.07 ≤ L / C ≤ 0.333.

[0084] It should be noted that the first arc-shaped weld mark 151 and the second arc-shaped weld mark 152 can be weld marks formed using a sealing welding process, and the connection between the first arc-shaped weld mark 151 and the second arc-shaped weld mark 152 also uses a sealing welding process for transition. Through the complete sealing connection of the first arc-shaped weld mark 151 and the second arc-shaped weld mark 152, a reliable sealing welding structure is ensured between the cover plate 140 and the opening 112 of the side wall 111.

[0085] It should be understood that, for the convenience of the welding process, the first arc-shaped weld mark 151 and the second arc-shaped weld mark 152 are typically coaxially or approximately coaxially arranged with the housing 110. Provided that the sealing performance requirements between the cover plate 140 and the opening 112 of the side wall 111 are met, the radii of the first arc-shaped weld mark 151 and the second arc-shaped weld mark 152 can be equal or unequal. Optionally, in this embodiment, to optimize the welding transition effect between the first arc-shaped weld mark 151 and the second arc-shaped weld mark 152, the radii of the first arc-shaped weld mark 151 and the second arc-shaped weld mark 152 are approximately equal.

[0086] In this embodiment, the cover plate 140 is connected to the second connecting part 132 and the side wall 111 by multiple first arc-shaped weld marks 151, achieving triple sealing welding between the cover plate 140, the current collecting member 130, and the side wall 111. The cover plate 140 is also connected to the side wall 111 by multiple second arc-shaped weld marks 152, achieving double sealing welding between the cover plate 140 and the side wall 111. This design allows for triple welding only in localized areas of the cover plate 140's circumference, while only double welding is required in other areas. Through the above design, multiple spaced first arc-shaped weld marks 151 and second arc-shaped weld marks 152 are formed around the cover plate 140, decomposing the traditional continuous circumferential welding into multiple independent arc-shaped welding segments. Each arc-shaped weld mark (including the first arc-shaped weld mark 151 and the second arc-shaped weld mark 152) can be independently positioned and calibrated during the welding process, thereby effectively compensating for the deviation between the weldable position and the predetermined laser welding trajectory caused by the roundness error of the shell opening. Specifically, the segmented welding method can dynamically adjust the welding trajectory according to the actual mating position of each segment, avoiding welding offset caused by cumulative errors. Compared with continuous welding around the entire circumference, this segmented weld mark design can reduce the maximum trajectory deviation within the range of a single arc-length weld mark, thereby improving the welding position accuracy, reducing missed welds or weld deviations during the welding process, and thus ensuring the welding quality between the cover plate 140 and the side wall 111, and improving the welding yield when laser sealing welding is performed at the opening 112 of the shell 110.

[0087] Meanwhile, since the welding heat required for triple welding is significantly greater than that for double welding, compared to the traditional solution that requires triple sealing welding across the entire circumference of the cover plate 140, this solution effectively reduces the total heat input during the sealing welding of the cover plate 140 by rationally allocating the welding area. This heat control method can effectively reduce thermal damage to the internal electrode assembly 120 during the welding process, thereby improving the overall safety performance of the cylindrical battery 100.

[0088] Furthermore, during the mass production of the cylindrical battery 100, due to limitations in the processing technology, the roundness of the opening 112 of the casing 110 on the production line is prone to be poor, and there are also differences in roundness between different casings 110. This will cause a deviation between the welding position where the opening 112 mates with the cover plate 140 and the predetermined laser welding trajectory. It is understandable that the longer the laser welding trajectory, the greater the deviation between the two. For example, when the laser welding trajectory is a circumferentially closed circle, the laser welding trajectory will completely deviate from the welding position where the opening 112 mates with the cover plate 140 at a certain position in the circumference.

[0089] To address this issue, this embodiment employs the following solution: controlling the ratio of the arc length L of each first arc-shaped weld mark 151 to the circumference C of the sidewall 111 to satisfy: 0.07 ≤ L / C ≤ 0.333. When the ratio of the arc length L of the first arc-shaped weld mark 151 to the circumference C of the sidewall 111 is less than 0.07, the reliability of the connection structure at the triple welding position decreases, and the current carrying capacity is insufficient. Conversely, when the ratio of the arc length L of the first arc-shaped weld mark 151 to the circumference C of the sidewall 111 is greater than 0.333, the laser welding trajectory is prone to deviating from the mating position of the opening 112 and the cover plate 140, resulting in welding defects such as incomplete welding. Therefore, in this embodiment, by limiting the ratio of the arc length L of the first arc-shaped weld mark 151 to the circumference C of the sidewall 111 to 0.07 ≤ L / C ≤ 0.333, both the reliability of the welding connection between the cover plate 140 and the sidewall 111 and the accuracy of the welding position can be considered. Furthermore, compared to existing technologies, this design can effectively reduce the total heat input during the sealing welding of the cover plate 140 without increasing the width of the solder mark 151, and avoids the problem of missed soldering.

[0090] In addition, since the current collector 130 is provided with multiple second connecting parts 132, the deformation generated by the contact between the second connecting parts 132 and the side wall 111 during the assembly of the current collector 130 into the housing can absorb at least part of the assembly error between the current collector 130 and the housing 110. This not only improves the assembly tolerance capability, but also improves the assembly process performance between the current collector 130 and the housing 110.

[0091] Please see Figure 3 In one embodiment of this utility model, the ratio of the arc length L of the first arc-shaped weld mark 151 to the perimeter C of the sidewall 111 satisfies: 0.1 ≤ L / C ≤ 0.2. Compared with the previous embodiment, this embodiment further limits the ratio of the arc length L of the first arc-shaped weld mark 151 to the perimeter C of the sidewall 111 to the range of 0.1 ≤ L / C ≤ 0.2, which can more accurately optimize the input of welding heat. This not only avoids the first arc-shaped weld mark 151 being too short, thus ensuring the welding strength of the first arc-shaped weld mark 151, but also prevents the laser welding trajectory from deviating from the mating position of the opening 112 and the cover plate 140 due to the first arc-shaped weld mark 151 being too long, reducing the probability of incomplete welding. At the same time, this process can also avoid the waste of welding heat caused by the first arc-shaped weld mark 151 being too long, thereby further optimizing the laser sealing welding process.

[0092] Please see Figures 5 to 8In one embodiment of this utility model, a sidewall 111 is disposed around the outer periphery of a cover plate 140, and at least a portion of a second connecting portion 132 extends in a direction away from the electrode assembly 120 and is sandwiched between the sidewall 111 and the cover plate 140. Specifically, at least a portion of the second connecting portion 132 extends axially along the housing 110; along the radial direction of the cover plate 140, the outer periphery of the cover plate 140 faces the inner wall of the sidewall 111 and forms an annular butt joint with the inner wall of the sidewall 111. At least a portion of the second connecting portion 132 is sandwiched within the annular butt joint. Welding is performed at the annular butt joint position along the circumferential direction of the cover plate 140, and a first arc-shaped weld mark 151 is formed between the outer periphery of the cover plate 140, the second connecting portion 132, and the inner wall of the sidewall 111, and a second arc-shaped weld mark 152 is formed between the outer periphery of the cover plate 140 and the inner wall of the sidewall 111.

[0093] The structure described in the above embodiment allows for convenient observation or visual inspection of the assembly gap in the radial direction between the cover plate 140 and the side wall 111 before welding, as well as the assembly gap between the cover plate 140, the second connecting portion 132, and the side wall 111. Therefore, it is easier to detect defective products before welding, thus avoiding ineffective welding. Simultaneously, this structure also facilitates observation or visual inspection of the welding quality of the first arc-shaped weld mark 151 and the second arc-shaped weld mark 152, making it easier to identify defective products after welding. This helps avoid the production of products with welding quality problems, reducing safety hazards associated with the cylindrical battery 100.

[0094] To ensure the welding quality between the cover plate 140, the side wall 111, and the second connecting portion 132, i.e., the welding strength of the first arc-shaped weld mark 151, optionally, please refer to... Figure 6 and Figure 8 In one embodiment of this utility model, the weld width of the first arc-shaped weld 151 is T1, and the weld width of the second arc-shaped weld 152 is T2, where T1 > T2. The weld depth of the first arc-shaped weld 151 is H1, and the weld depth of the second arc-shaped weld 152 is H2, where H1 > H2. It should be noted that the weld width of the first arc-shaped weld 151 is the width of the first arc-shaped weld 151 along the radial direction of the cover plate 140. The weld width of the second arc-shaped weld 152 is the width of the second arc-shaped weld 152 along the radial direction of the cover plate 140.

[0095] Since the triple welding between the cover plate 140, the second connecting portion 132, and the side wall 111 requires more welding heat than the double welding between the cover plate 140 and the side wall 111, in this embodiment, on the one hand, the weld width T1 of the first arc-shaped weld mark 151 (triple welding area) is limited to be greater than the weld width T2 of the second arc-shaped weld mark 152 (double welding area), and the weld depth H1 of the first arc-shaped weld mark 151 is limited to be greater than the weld depth H2 of the second arc-shaped weld mark 152. This allows the cross-sectional area of ​​the molten pool of the first arc-shaped weld mark 151 (T1×H1) to be greater than the cross-sectional area of ​​the molten pool of the second arc-shaped weld mark 152 (T2×H2). This setting ensures that the triple welding area has a larger molten pool cross-sectional area, resulting in more complete welding fusion and effectively avoiding the generation of incomplete penetration defects. At the same time, since the double welding area has a smaller molten pool cross-section, this solution can relatively reduce the heat input during the welding process compared to a solution where the entire circumference of the cover plate 140 is triple welded.

[0096] In another embodiment, the weld width of the first arc-shaped weld 151 can be T1, and the weld width of the second arc-shaped weld 152 can be T2, with T1 > T2. That is, only the weld width T1 of the first arc-shaped weld 151 is limited to be greater than the weld width T2 of the second arc-shaped weld 152. With this setting, under the condition that the weld depth of the first arc-shaped weld 151 and the weld depth of the second arc-shaped weld 152 are the same, it can also be ensured that the cross-sectional area of ​​the weld pool of the first arc-shaped weld 151 is greater than the cross-sectional area of ​​the weld pool of the second arc-shaped weld 152 (that is, the weld cross-sectional area), thereby achieving the beneficial effects of the above embodiments.

[0097] In other embodiments, the penetration depth of the first arc-shaped solder joint 151 can be H1, and the penetration depth of the second arc-shaped solder joint 152 can be H2, where H1 > H2. This configuration ensures that, under the condition that the penetration width of the first arc-shaped solder joint 151 and the penetration width of the second arc-shaped solder joint 152 are the same, the cross-sectional area of ​​the molten pool of the first arc-shaped solder joint 151 is larger than that of the molten pool of the second arc-shaped solder joint 152, thus achieving the beneficial effects described in the above embodiments.

[0098] Please see Figure 6 and Figure 8 In one embodiment of the present invention, a sidewall 111 is disposed around the outer periphery of a cover plate 140, and at least a portion of the second connecting portion 132 extends toward the direction away from the electrode assembly 120. Specifically, at least a portion of the second connecting portion 132 extends axially along the housing 110 and is sandwiched between the sidewall 111 and the cover plate 140. The thickness of the second connecting portion 132 is T3, where 1.1×T3 < T1 < 2.67×T3, and 1.1×T3 < T2 < 2.67×T3.

[0099] In this embodiment, under the premise of 0.07≤L / C≤0.333, even if there is some offset between the centerline of a certain welding position where the opening 112 and the cover plate 140 meet and the centerline of the laser welding trajectory, by controlling the weld width T1 of the first arc-shaped weld mark 151 to satisfy 1.1×T3<T1, it can be ensured that the first arc-shaped weld mark 151 better covers the welding position where the opening 112 and the cover plate 140 meet. Furthermore, by controlling T1<2.67×T3, it is also possible to prevent the weld width of the first arc-shaped weld mark 151 from being too large, which would lead to excessive welding heat input and avoid thermal damage to the electrode assembly 120 due to an excessively large heat-affected zone, thereby reducing the safety performance of the cylindrical battery 100.

[0100] Please see Figure 5 and Figure 6 In one embodiment of this utility model, the cover plate 140 includes a body portion 141, a deformable portion 142, and a third connecting portion 143. The body portion 141 is disposed in the central region of the cover plate 140, the deformable portion 142 is disposed around the outer periphery of the body portion 141, and the third connecting portion 143 is disposed around the outer periphery of the deformable portion 142. Along the radial direction of the cover plate 140, one end of the deformable portion 142 is connected to the third connecting portion 143, and the other end is connected to the body portion 141. The third connecting portion 143 extends axially along the housing 110. An annular recess 144 is formed on the side of the deformable portion 142 facing the electrode assembly 120, and an annular protrusion 145 is formed on the side of the deformable portion 142 facing away from the electrode assembly 120. The forming method of the annular recess 144 and the annular protrusion 145 is not limited, for example, it can be formed by mold casting or by conventional mold stamping. Optionally, in this embodiment, both the annular recess 144 and the annular protrusion 145 are structures formed by stamping deformation of the deformable portion 142.

[0101] The specific structural shapes of the annular recess 144 and the annular protrusion 145 are not limited; for details, please refer to [link / reference needed]. Figure 6 In this embodiment, the deformable portion 142 includes a first annular wall 1421, a second annular wall 1422, and a top wall 1423 connecting the first annular wall 1421 and the second annular wall 1422. The top wall 1423 is disposed on the side away from the electrode assembly 120. The first annular wall 1421 connects the outer periphery of the body portion 141 and the inner edge of the top wall 1423. The second annular wall 1422 connects the end of the third connecting portion 143 near the electrode assembly 120 and the outer edge of the top wall 1423. The other end of the third connecting portion 143 extends axially toward the opening 112 along the housing 110. Along the radial direction of the cover plate 140, the side of the third connecting portion 143 opposite to the deformable portion 142 abuts against the side wall 111 or the second connecting portion 132.

[0102] Using the cover plate 140 structure in the above embodiment, when the cover plate 140 is assembled to the opening 112, applying a clamping force to the top of the cover plate 140 (i.e., the annular protrusion 145) causes the deformable part 142 to deform, allowing the third connecting part 143 to be pressed radially against the inner wall of the side wall 111 or the second connecting part 132. This effectively eliminates the gap between the third connecting part 143 and the side wall 111 or the second connecting part 132, avoiding welding defects (such as incomplete fusion, porosity, etc.) caused by excessive gaps.

[0103] Based on the previous embodiment, please refer to the following further examples. Figure 6 In one embodiment of the present invention, along the axial direction of the housing 110, the side of the third connecting portion 143 facing away from the electrode assembly 120 includes a first end face 1431, and the side of the second connecting portion 132 facing away from the electrode assembly 120 includes a second end face 1325. The first end face 1431 and the second end face 1325 are flush or substantially flush, and the area where the deformable portion 142 and the third connecting portion 143 are connected is at least partially pressed against the first connecting portion 131.

[0104] By making the first end face 1431 flush or nearly flush with the side end face of the second connecting portion 132 facing away from the electrode assembly 120, a large contact area in the axial direction can be ensured between the cover plate 140 and the second connecting portion 132, thereby ensuring the stability of the assembly relationship between the two and facilitating the formation of a stable and reliable welded connection between the cover plate 140 and the second connecting portion 132. Simultaneously, since the connection area between the deformable portion 142 and the third connecting portion 143 is at least partially pressed against the first connecting portion 131, it can be ensured that the deformable portion 142 can undergo radial deformation when the cover plate 140 is pressed, thereby ensuring that the third connecting portion 143 is pressed tightly against the inner wall of the side wall 111 or the second connecting portion 132, reducing the probability of a large gap between the third connecting portion and the side wall 111 or the second connecting portion 132, and further improving the welding quality.

[0105] Please see Figures 10 to 13 In one embodiment of this utility model, the outer peripheral surface of the third connecting portion 143 is provided with a plurality of grooves 160 in the circumferential direction. The shape and number of the grooves 160 match the shape and number of the second connecting portions 132. The inner wall of the side wall 111 is a smooth cylindrical surface structure surrounding the outer periphery of the grooves 160. Along the axial direction of the housing 110, the groove 160 includes a groove opening 161 facing the outside of the cover plate 140. A second connecting portion 132 is accommodated in a groove 160, and at least part of the end of the second connecting portion 132 away from the electrode assembly 120 is exposed in the groove opening 161.

[0106] In another embodiment, please refer to Figure 17Alternatively, the groove 160 can be disposed on the inner wall of the side wall 111, and the third connecting portion 143 can be a smooth cylindrical surface structure surrounding the inner circumference of the groove 160. In other embodiments, the groove 160 can also include two groove portions that abut each other, one groove portion being disposed on the inner wall of the side wall 111, and the other groove portion being disposed on the outer circumferential surface of the third connecting portion 143, the two groove portions abutting each other to form the groove 160 described above, and the second connecting portion 132 being accommodated within the groove 160.

[0107] By providing multiple grooves 160 on the outer peripheral surface of the third connecting portion 143 and / or the inner wall of the side wall 111, and accommodating the second connecting portion 132 within the grooves 160, this arrangement serves two purposes. First, the gaps between adjacent second connecting portions 132 can be filled by the protrusions formed between the grooves 160, reducing the mating gap between the third connecting portion 143 and the side wall 111 in areas where the second connecting portion 132 is not provided. This allows for a tighter fit between the third connecting portion 143 and the side wall 111, thereby improving the welding quality of the first arc-shaped weld mark 151 and increasing the welding yield. Second, since the second connecting portion 132 can be accommodated within the grooves 160, the grooves 160 also facilitate the assembly and positioning of the cover plate 140, the current collecting member 130, and the side wall 111, improving assembly efficiency and positioning accuracy.

[0108] When the groove 160 is provided on the inner wall of the side wall 111, the groove 160 can be formed in various ways on the side wall 111, such as by cutting or thinning. Optionally, please refer to Figures 17 to 19 In one embodiment of this utility model, the inner wall of the sidewall 111 includes a thinning area, which forms the aforementioned groove 160. Along the circumference of the sidewall 111, the area between adjacent thinning areas is welded to the third connecting portion 143 to form a second arc-shaped weld mark 152. By providing a thinning area on the inner wall of the sidewall 111 to form the groove 160, the forming process of the groove 160 can be achieved without significantly reducing the overall structural strength of the sidewall 111.

[0109] Please see Figures 10 to 13In one embodiment of this utility model, a groove 160 is formed on the third connecting portion 143 of the cover plate 140, and a protrusion 146 formed between multiple grooves 160 abuts and welds to the inner wall of the side wall 111 to form a second arc-shaped weld mark 152. The groove 160 on the third connecting portion 143 can be formed by cutting, casting, etc., and this embodiment is not limited to this. Specifically, the groove 160 penetrates the third connecting portion 143 along the thickness direction of the cover plate 140. In this embodiment, by forming the groove 160 on the third connecting portion 143, that is, on the outer periphery of the cover plate 140, this arrangement is more convenient for the forming and processing of the groove 160 compared to the solution of forming the groove 160 on the side wall 111, which helps to reduce the processing cost of the groove 160. Compared to the solution of forming the groove 160 on the side wall 111, which may further affect the roundness of the opening 112, setting the groove 160 on the cover plate 140 is more conducive to the assembly and welding of the cylindrical battery 100.

[0110] Please see Figures 20 to 22 In one embodiment of this utility model, an assembly gap 163 is formed on at least one side between the second connecting portion 132 and the groove 160 along the circumferential direction of the cover plate 140. For example, the assembly gap 163 may be formed on one side of the assembly position between the second connecting portion 132 and the groove 160, or it may be formed on both sides of the assembly position between the second connecting portion 132 and the groove 160. Optionally, in this embodiment, an assembly gap 163 is formed on both sides of the assembly position between the second connecting portion 132 and the groove 160 along the circumferential direction of the cover plate 140. By providing the assembly gap 163, the second connecting portion 132 can be easily installed into the interior of the groove 160, reducing the assembly difficulty.

[0111] Please see Figure 21 and Figure 22 Along the axial direction of the housing 110, a pre-formed solder portion 162 is provided on the end face of the second connecting portion 132 opposite to the electrode assembly 120; and / or, a pre-formed solder portion 162 is provided on the end face of the groove 160 opposite to the electrode assembly 120. The position of the pre-formed solder portion 162 corresponds to the position of the assembly gap 163. The pre-formed solder portion 162 is configured to melt and fill the assembly gap 163 during the forming process of the first arc-shaped solder mark 151.

[0112] Specifically, in one embodiment, please refer to Figure 22 and Figure 25 A pre-formed solder portion 162 is provided on the second end face 1325 of the second connecting portion 132, which corresponds to one of the assembly gaps 163. Please refer to [link / reference]. Figure 21 and Figure 23Another pre-made solder part 162 is provided on the end face of the groove 160 opposite to the electrode assembly 120, and this pre-made solder part 162 corresponds to another assembly gap 163.

[0113] In another embodiment, two pre-installed solder portions 162 are provided on the second end face 1325 of the second connecting portion 132, and the two pre-installed solder portions 162 correspond to the assembly gaps 163 on both sides respectively. In other embodiments, two pre-installed solder portions 162 are provided on the end face of the groove 160 on the side opposite to the electrode assembly 120, and the two pre-installed solder portions 162 correspond to the assembly gaps 163 on both sides respectively.

[0114] It should be noted that, in the above embodiments, please refer to... Figure 21 and Figure 23 When the groove 160 is formed on the inner wall of the sidewall 111, the end face of the groove 160 facing away from the electrode assembly 120 corresponds to the end face of the sidewall 111 facing away from the electrode assembly 120. Please refer to [link / reference]. Figure 28 and Figure 30 When the groove 160 is formed on the third connecting part 143, the end face of the groove 160 facing away from the electrode assembly 120 corresponds to the end face of the side wall 111 facing away from the electrode assembly 120, which is the first end face 1431 of the third connecting part 143.

[0115] The forming method of the pre-made solder part 162 on the side wall 111 or the third connecting part 143 is not limited, such as adhesive connection, snap connection, welding connection and other methods.

[0116] In the above embodiments, by providing a pre-made solder section 162 and configuring it to melt and fill the assembly gap 163 during the forming process of the first arc-shaped solder mark 151, this configuration allows the pre-made solder section 162 to melt and fill the assembly gap 163 between the second connecting part 132 and the groove 160 during the welding process. This avoids defects such as incomplete welding or porosity caused by an excessively large assembly gap 163, thereby improving the sealing performance and mechanical strength of the weld interface. Simultaneously, the presence of the pre-made solder section 162 allows for a certain assembly gap 163 between the second connecting part 132 and the groove 160, reducing the difficulty of achieving precise fit and assembly positioning, and further improving assembly efficiency.

[0117] Please see Figures 31 to 33In one embodiment of this utility model, a sidewall 111 is disposed around the outer periphery of a cover plate 140 and abuts against the outer peripheral edge of the cover plate 140. The sidewall 111 is also disposed around the outer periphery of a second connecting portion 132 and abuts against or is adjacent to the outer peripheral edge of the second connecting portion 132. The second connecting portion 132 abuts against the surface of the cover plate 140 facing the electrode assembly 120. That is, the cover plate 140 and the second connecting portion 132 are stacked along the axial direction of the housing 110. A first arc-shaped solder mark 151 is formed in the contact or adjacent area of ​​the sidewall 111, the cover plate 140, and the second connecting portion 132. The weld pool portion of the first arc-shaped solder mark 151 extends into the interior of the sidewall 111 and partially penetrates the cover plate 140 to the interior of the second connecting portion 132, thereby achieving welding between the sidewall 111, the cover plate 140, and the second connecting portion 132. The second arc-shaped weld mark 152 is formed in the mating or adjacent area of ​​the side wall 111 and the cover plate 140, and the weld pool of the second arc-shaped weld mark 152 is partially located inside the side wall 111 and partially located inside the cover plate 140, so as to realize the welding between the side wall 111 and the cover plate 140.

[0118] By adopting the structural design in the above embodiment, penetration welding between the cover plate 140 and the second connecting part 132 can be achieved. This makes it easier to form a continuous and stable sealing welding layer among the side wall 111, the cover plate 140 and the second connecting part 132, effectively improving the welding sealing performance of the first arc-shaped weld mark 151, and thus helping to improve the welding yield of the product.

[0119] Please see Figure 32 In one embodiment of this utility model, the second connecting portion 132 includes a bent section 1321 and an extension section 1322. The bent section 1321 connects the extension section 1322 and the first connecting portion 131. The extension section 1322 extends toward the cover plate 140 along the axial direction of the housing 110 and abuts against the cover plate 140. At least a portion of the first arc-shaped weld mark 151 extends into the extension section 1322. The bent section 1321 may include one bent structure or multiple bent structures, as long as it can bend and deform when the current collecting member 130 and the cover plate 140 are mated and pressed together.

[0120] In this embodiment, by providing a bending section 1321, when the cover plate 140 and the current collecting member 130 are assembled, the deformation of the bending section 1321 can absorb the deformation stress generated when the extension section 1322 abuts against the cover plate 140, thereby helping to reduce the deformation stress transmitted to the first connecting part 131 and reducing the adverse effects on the welding position of the first connecting part 131 and the electrode lug.

[0121] Please see Figure 32 and Figure 33In one embodiment of this utility model, the inner wall of the sidewall 111 includes a stepped portion 113, and the stepped portion 113 includes a supporting surface 1131. The bent segment 1321 is at least partially supported on the supporting surface 1131. The stepped portion 113 is a ring structure surrounding the inner wall of the sidewall 111. The supporting surface 1131 is a ring-shaped structure coaxially arranged with the sidewall 111. The supporting surface 1131 can be a ring-shaped planar structure, a ring-shaped curved surface structure, or a ring-shaped inclined surface structure, etc. Optionally, in this embodiment, the supporting surface 1131 is a ring-shaped curved surface structure that matches the shape of the bent segment 1321. This allows for a relatively close fit between the supporting surface 1131 and the bent segment 1321, which can effectively reduce the displacement or deformation that may occur in the bent segment 1321 during use, thereby significantly improving the stability of the support.

[0122] It should be noted that you should refer to [link / reference]. Figure 32 The stepped portion 113 also includes a stepped sidewall 1132 connected to the support surface 1131, the stepped sidewall 1132 extending axially along the housing 110. Along the radial direction of the housing 110, the extension 1322 abuts against the stepped sidewall 1132, and the outer periphery of the cover plate 140 also abuts against the stepped sidewall 1132. At least a portion of the second arc-shaped weld mark 152 extends into the interior of the stepped portion 113. This arrangement not only facilitates the forming process of the stepped portion 113 on the sidewall 111, but also allows for the radial alignment of the cover plate 140 and the second connecting portion 132, facilitating positioning and installation.

[0123] It is understood that in other embodiments, the step portion 113 may also be a plurality of partial step structures spaced apart on the inner wall of the side wall 111, each step structure corresponding to a second connecting portion 132, that is, each step structure is provided with a support surface 1131 to support a bent segment 1321.

[0124] Please see Figures 35 to 37 In one embodiment of this utility model, the second connecting portion 132 includes a straight section 1323 and a connecting section 1324. The straight section 1323 is connected to the first connecting portion 131 through the connecting section 1324. The angle between the connecting section 1324 and the straight section 1323 is α, and α is less than 180°. The straight section 1323 is parallel to the surface of the cover plate 140 facing the electrode assembly 120, and the end of the straight section 1323 away from the connecting section 1324 abuts against or is close to the inner wall of the side wall 111. The connecting section 1324 can be arranged perpendicularly to the straight section 1323 or inclined, as long as the angle α between the connecting section 1324 and the straight section 1323 is less than 180°.

[0125] In this embodiment, since the straight section 1323 is parallel to the surface of the cover plate 140 facing the electrode assembly 120, this design allows for a larger contact area between the second connecting portion 132 and the cover plate 140. This larger contact area provides favorable conditions for penetration welding between the cover plate 140 and the second connecting portion 132, which helps ensure the stability and reliability of the welding process. Simultaneously, since the angle between the connecting section 1324 and the straight section 1323 is less than 180°, a bending structure can be formed between them. When assembling the current collector 130 and the cover plate 140, the bending deformation generated by the second connecting portion 132 can absorb the assembly error between the second connecting portion 132 and the housing 110. This makes it easier to assemble the current collector 130 into the housing 110, thereby improving assembly efficiency.

[0126] Please see Figure 36 In one embodiment of this utility model, the inner wall of the sidewall 111 includes a stepped portion 113, the stepped portion 113 includes a supporting surface 1131, and a straight section 1323 is at least partially sandwiched between the supporting surface 1131 and the cover plate 140 along the thickness direction of the cover plate 140. Specifically, the supporting surface 1131 is an annular structure that is substantially coaxial with the sidewall 111. At least a portion of the straight section 1323 overlaps the supporting surface 1131, and the surface of the cover plate 140 facing the electrode assembly 120 is pressed against the straight section 1323, thereby realizing the arrangement of the straight section 1323 being sandwiched between the supporting surface 1131 and the cover plate 140.

[0127] This design improves the positioning accuracy between the straight section 1323, the side wall 111, and the cover plate 140, thus enhancing welding precision. Furthermore, during penetration welding of the cover plate 140, the support surface 1131 of the step portion 113 acts as a physical barrier, reducing or even preventing the projections of the first arc-shaped weld mark 151 and the second arc-shaped weld mark 152 along the axial direction of the housing 110 from falling into the axial projection of the electrode assembly 120, further minimizing the thermal impact.

[0128] Please see Figures 39 to 42In one embodiment of the present invention, the sidewall 111 near the opening 112 includes a supporting end face 116, and the outer periphery of the cover plate 140 overlaps the supporting end face 116. At least a portion of the second connecting portion 132 extends radially along the housing 110 and is sandwiched between the sidewall 111 and the cover plate 140. Specifically, the cover plate 140 and the sidewall 111 are joined together along the axial direction of the housing 110 to form an annular butt joint, which extends radially along the housing 110, and the second connecting portion 132 is at least partially sandwiched within the annular butt joint. Along the circumferential direction of the sidewall 111, welding is performed at the position of the annular butt joint on the outer periphery of the housing 110, and a first arc-shaped weld mark 151 is formed between the outer periphery of the cover plate 140, the second connecting portion 132, and the supporting end face 116, and a second arc-shaped weld mark 152 is formed between the outer periphery of the cover plate 140 and the supporting end face 116.

[0129] Compared to welding the top of the cover plate 140, the structure used in this embodiment allows welding of the cover plate 140, side wall 111, and current collector 130 to the outer circumferential side of the housing 110. During the assembly of the current collector 130, metal shavings generated by the friction between the current collector 130 and the side wall 111 remain at the interface between the current collector 130 and the side wall 111, rather than falling directly into the interior of the housing 110, thereby reducing the risk of foreign matter contamination to the electrode assembly 120.

[0130] Please see Figures 42 to 45 In one embodiment of this utility model, the sidewall 111 near the opening 112 has a plurality of grooves 160 in the circumferential direction. The number of grooves 160 corresponds to the number of second connecting parts 132, that is, each groove 160 corresponds to one second connecting part 132. The groove 160 includes a groove opening 161, which faces away from the other end of the sidewall 111, specifically the end of the sidewall 111 near the end wall 114. The groove 160 penetrates the sidewall 111 radially along the housing 110. The second connecting part 132 is accommodated in the groove 160. The sidewall 111 near the opening 112 includes a supporting end face 116. The outer periphery of the cover plate 140 overlaps the supporting end face 116, and the cover plate 140 covers the groove opening 161 and presses the second connecting part 132 into the groove 160. To improve the welding quality between the second connecting part 132 and the groove 160 and the cover plate 140, in one embodiment, the end face of the second connecting part 132 overlapping the groove 160 is flush or substantially flush with the outer peripheral surface of the side wall 111 along the radial direction of the housing 110.

[0131] This design has two advantages. First, since the groove 160 can accommodate the thickness of the second connecting portion 132, the mating gap between the cover plate 140 and the support end face 116 can be reduced. This allows for a tighter fit between the cover plate 140 and the support end face 116, which in turn improves the welding quality of the first arc-shaped weld mark 151 and increases the welding yield. Second, since the second connecting portion 132 can be accommodated within the groove 160, the groove 160 can provide a positioning function for the installation of the current collecting member 130 and the housing 110, thereby improving assembly efficiency and positioning accuracy.

[0132] Further, please refer to Figure 42 , Figure 47 and Figure 48 In this embodiment, along the circumferential direction of the housing 110, at least one side of the second connecting portion 132 and the groove 160 forms the assembly gap 163 as described in the above embodiment. A pre-formed solder portion 162 is provided at one end of the groove 160 facing the outside of the housing 110 and / or at one end of the second connecting portion 132 facing the outside of the housing 110. The arrangement of the pre-formed solder portion can be referred to the relevant description in the above embodiments, and will not be repeated here.

[0133] Please see Figure 46 In one embodiment of this utility model, the second connecting portion 132 includes a straight section 1323 and a connecting section 1324. The straight section 1323 is connected to the first connecting portion 131 via the connecting section 1324 and extends into the groove 160 along the radial direction of the housing 110. Along the axial direction of the housing 110, one end of the connecting section 1324 is connected to the first connecting portion 131, and the other end extends toward the cover plate 140 and connects to the straight section 1323. The included angle α between the connecting section 1324 and the straight section 1323 is less than 180°. The side of the cover plate 140 facing the electrode assembly 120 includes a positioning surface 148. The positioning surface 148 abuts against the side of the connecting section 1324 near the straight section 1323 to press the straight section 1323 into the groove 160 along the radial direction of the housing 110. The specific structure of the positioning surface 148 is not limited. It can be multiple protruding structures provided on the cover plate 140, with part of the outer wall of the protruding structure forming the positioning surface 148; or it can be an annular protruding structure provided on the cover plate 140, with the outer ring wall of the annular protruding structure forming the positioning surface 148.

[0134] Specifically, in this embodiment, the outer periphery of the cover plate 140 is provided with an annular groove 147 on the side facing the electrode assembly 120. The annular groove 147 includes an annular bottom wall 1471 and an annular side wall 1472. The annular bottom wall 1471 abuts against the support end face 116, and the annular side wall 1472 forms a positioning surface 148, which abuts against the side of the connecting section 1324 near the straight section 1323.

[0135] Since the angle between the connecting section 1324 and the straight section 1323 is less than 180°, a bending structure can be formed between them. This bending structure can absorb some of the assembly errors generated during the assembly of the current collector 130 and the housing 110 through its own bending deformation, thereby improving the assembly efficiency between the current collector 130 and the housing 110 and reducing the assembly difficulty caused by tolerance accumulation. At the same time, since the positioning surface 148 on the cover plate 140 can abut against the connecting section 1324, it can generate a resisting force on the straight section 1323 towards the radially outward side of the housing 110. This helps the straight section 1323 to form a stable radial positioning within the groove 160, reducing the possibility of relative displacement between the straight section 1323 and the groove 160 during welding, thereby improving the welding quality between the second connecting part 132 and the groove 160 and the cover plate 140.

[0136] Please see Figure 49 In one embodiment of the battery pack 200 of this utility model, the battery pack 200 includes a housing 210 and at least one cylindrical battery 100. The housing 210 includes a first housing portion 211 and a second housing portion 212, which cover each other to form a receiving space. Multiple cylindrical batteries 100 are housed within the receiving space, and the multiple cylindrical 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.

[0137] Please see Figure 50In one example of the electronic device 300 of this utility model, the electronic device 300 includes a working part 310 and a battery pack 200. The working part 310 is electrically connected to the battery pack 200 to obtain electrical power. The working part 310 can be a unit component capable of obtaining electrical power from the battery pack 200 and performing corresponding work, such as a fan blade rotation unit, a vacuum cleaner suction unit, or a wheel drive unit in an electric vehicle. The electronic device 300 can be a vehicle, mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This utility model embodiment does not impose special limitations on the above-mentioned electronic device 300. In one embodiment of the electronic device 300 of this utility model, the electronic device 300 is a vehicle, the working part 310 is the vehicle body, and the battery pack 200 is fixedly installed on the vehicle body, thereby providing driving force for the vehicle to operate.

[0138] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A cylindrical battery, characterized by comprising: include: Cover plate; A housing, the housing including a sidewall having at least one opening, the cover sealing at least one of the openings; An electrode assembly is housed within the housing, and the electrode assembly has tabs on the side facing the opening; A current collector is disposed on the side of the electrode assembly facing the cover plate, and includes a first connecting part and a plurality of second connecting parts. The first connecting part is welded to the electrode tab, and the plurality of second connecting parts are spaced apart around the outer periphery of the first connecting part. The cover plate is connected to the second connecting part and the side wall by a plurality of first arc-shaped weld marks, and the cover plate is connected to the side wall by a plurality of second arc-shaped weld marks. The ratio of the arc length L of each first arc-shaped weld mark to the perimeter C of the side wall satisfies: 0.1≤L / C≤0.2; the weld width of the first arc-shaped weld mark is T1, the weld width of the second arc-shaped weld mark is T2, and T1>T2; and / or, the weld depth of the first arc-shaped weld mark is H1, the weld depth of the second arc-shaped weld mark is H2, H1>H2, and the thickness of the second connecting part is T3, 1.1×T3<T1<2.67×T3.

2. The cylindrical battery according to claim 1, characterized by The sidewall is disposed around the outer periphery of the cover plate, and at least a portion of the second connection extends in a direction away from the electrode assembly and is sandwiched between the sidewall and the cover plate.

3. The cylindrical battery according to claim 2, characterized in that, The outer periphery of the cover plate is provided with a plurality of grooves in the circumferential direction. Along the axial direction of the housing, the grooves include groove openings facing the outer side of the cover plate. The second connecting portion is accommodated in the grooves and is at least partially exposed in the groove openings. The protrusions formed between the plurality of grooves abut against the inner wall of the sidewall to form the second arc-shaped weld mark.

4. The cylindrical battery according to claim 1, characterized by, The sidewall near the opening includes a first end face, and the outer periphery of the cover plate overlaps the first end face; at least a portion of the second connecting portion extends radially along the housing and is sandwiched between the sidewall and the cover plate.

5. The cylindrical battery according to claim 4, characterized by The sidewall near the opening has a plurality of grooves in the circumferential direction. The groove openings are opposite to the other end of the sidewall, and the grooves penetrate the sidewall radially along the housing. The second connecting part is accommodated in the groove. The cover plate covers the groove opening and presses the second connecting part into the groove.

6. The cylindrical battery according to claim 5, characterized by The second connecting portion includes a straight section and a connecting section. The straight section is connected to the first connecting portion through the connecting section and extends into the groove along the radial direction of the housing. The included angle between the connecting section and the straight section is less than 180°. The cover plate has a positioning surface on the side facing the electrode assembly. The positioning surface presses against the connecting section to press the straight section into a predetermined position in the groove.

7. A battery pack characterized by comprising: The cylindrical battery includes any one of claims 1 to 6.

8. An electronic device, comprising: Includes the battery pack as described in claim 7.

Images