Assembly method of cylindrical battery

Abstract

The invention provides an assembling method of a cylindrical battery. The assembling method comprises the following steps: a first assembling step: providing an electrode assembly; providing a current collecting component, wherein the current collecting component comprises a first connecting part and a second connecting part; welding and fixing the first connecting part and the tab to form an electrode assembly component, wherein the second connecting part and the electrode assembly are positioned on the two sides of the first connecting part; the second assembling step comprises the steps that a shell is provided, the shell comprises a surrounding side wall, and at least one end of the side wall is provided with an opening; installing the electrode assembling component into the shell from the opening; a cover plate is provided and placed in the opening, so that the second connecting part is clamped between the side wall and the cover plate, or the cover plate and the second connecting part abut against each other in the axial direction of the shell, and the outer peripheral surface of the cover plate and the outer peripheral surface of the second connecting part are both opposite to the inner wall of the side wall, and the situation that due to the fact that the cover plate and the current collecting component occupy the space in the shell, the size is large can be relieved; and further improvement of the energy density of the cylindrical battery is restricted.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a method for assembling a cylindrical battery. Background Technology

[0002] Cylindrical batteries are gradually becoming the main power source for electrical devices due to their recyclability. As the demand for cylindrical batteries increases, people are also raising their requirements for their performance in various aspects, especially for battery cycle performance. The energy density of a battery is an important parameter to ensure its cycle performance.

[0003] Existing cylindrical batteries consist of a cover plate, current collectors, electrode assemblies, and a cylindrical casing. Typically, the current collectors are placed between the electrode assemblies and the cover plate, and welded to the electrode assemblies, casing, and / or the cover plate to achieve electrical connection between the electrode assemblies and the casing. The space occupied by the cover plate and current collectors within the casing is a significant factor limiting further improvements in the energy density of cylindrical batteries. Optimizing the assembly method of the cover plate, current collectors, and casing to improve energy density is a pressing technical challenge that needs to be overcome. Summary of the Invention

[0004] This invention provides an assembly method for cylindrical batteries to alleviate the technical problem that restricts further improvement of the energy density of cylindrical batteries due to the large space occupied by the cover plate and current collector in the casing.

[0005] This invention provides a method for assembling a cylindrical battery, the method comprising:

[0006] The first assembly step includes: providing an electrode assembly, the electrode assembly including a tab disposed at one end; providing a current collector, the current collector including a first connecting part and a second connecting part, the second connecting part being disposed around the outer periphery of the first connecting part; welding and fixing the first connecting part to the tab to form an electrode assembly, the second connecting part and the electrode assembly being located on both sides of the first connecting part;

[0007] The second assembly step includes: providing a housing, the housing including a surrounding sidewall, at least one end of the sidewall having an opening; installing an electrode assembly assembly into the housing through the opening; providing a cover plate and placing the cover plate in the opening such that the second connecting portion is clamped between the sidewall and the cover plate, or the cover plate and the second connecting portion abut against each other in the axial direction of the housing, the outer peripheral surface of the cover plate and the outer peripheral surface of the second connecting portion being opposite to the inner wall of the sidewall.

[0008] In one embodiment of the assembly method of the cylindrical battery of the present invention, the sidewall includes a first step portion disposed at one end near the cover plate. The first step portion includes a mating surface facing the cover plate and an inner circumferential surface surrounding the mating surface. The second connecting portion includes a first part and a second part. The second part extends from the inside to the outside along the radial direction of the cover plate. The first part connects the second part and the first connecting portion. A portion of the second part overlaps the mating surface.

[0009] A second stepped portion is provided on the outer periphery of the cover plate facing the electrode assembly. The second stepped portion includes an inclined wall and an annular surface connected to the radially outer end of the inclined wall. The annular surface faces the second portion and contacts the second portion, while the inclined wall faces the first portion and presses against the first portion. After the second assembly step, the method further includes:

[0010] The first shaping step includes: pressing the cover plate down along the axial direction of the shell, the inclined wall of the cover plate extruding the first part of the current collection member, the first part expanding outward along the radial outer side of the cover plate so that the outer peripheral surface of the second part abuts against the inner wall of the side wall;

[0011] The first welding step includes welding the sidewall, the second connecting part, and the cover plate together.

[0012] In one embodiment of the cylindrical battery assembly method of the present invention, the edge of the second connecting portion facing the electrode assembly is formed with a first chamfer; and / or, the radially inner edge of the opening is formed with a second chamfer; and / or, the edge of the cover plate facing the electrode assembly is formed with a third chamfer.

[0013] In one embodiment of the cylindrical battery assembly method of the present invention, the outer peripheral surface of the cover plate and the side wall are opposite to each other and have a gap, the outer peripheral surface of the second connecting part abuts against the side wall, the edge of the cover plate opposite to the electrode assembly is provided with a rounded corner, and the radially inner edge of the opening is provided with a chamfer.

[0014] Following the second assembly step, the method also includes:

[0015] The second welding step includes: laser-through-gap welding to connect the second connection part and the sidewall;

[0016] The third shaping step includes: rolling one end of the opening of the housing to make the housing cover the outer peripheral surface of the cover plate;

[0017] The third welding step includes welding the cover plate and sidewall together.

[0018] In one embodiment of the cylindrical battery assembly method of the present invention, the second connecting part extends in the direction away from the electrode assembly, the outer peripheral surface of the second connecting part is transitionally fitted or interference-fitted with the inner wall of the side wall, and the second connecting part is clamped between the side wall and the cover plate.

[0019] In one embodiment of the assembly method of the cylindrical battery of the present invention, the cover plate includes a body part, a deformable part and a third connecting part. The body part is located at the center of the cover plate. On the cross section through the axis of the cover plate, one end of the deformable part is connected to the third connecting part and the other end is connected to the body part. The third connecting part extends in a direction away from the electrode assembly. An annular recess is formed on the side of the deformable part facing the electrode assembly, and an annular protrusion is formed on the side of the deformable part away from the electrode assembly.

[0020] Following the second assembly step, the method also includes:

[0021] The fourth shaping step includes pressing the deformable part downward along the axial direction of the housing, the deformable part pushing the third connecting part to move radially outward toward the cover plate, so as to compress the second connecting part to tilt radially outward toward the cover plate, so that the outer peripheral surface of the second connecting part transitions or interferes with the inner wall of the side wall.

[0022] The first welding step includes welding the sidewall, the second connecting part, and the cover plate together.

[0023] In one embodiment of the assembly method of the cylindrical battery of the present invention, a fourth chamfer is formed on the radially inner edge of the second connecting portion; and / or, a fifth chamfer is formed on the radially inner edge of the opening.

[0024] In one embodiment of the assembly method for the cylindrical battery of the present invention, the second connecting portion is clamped between the side wall and the cover plate, and the method further includes:

[0025] The fifth shaping step includes: the shaping surface of the shaping fixture moves along the axial direction of the housing, and the pressing cover moves along the axial direction until the shaping surface abuts against the side wall;

[0026] The first welding step includes welding the sidewall, the second connecting part, and the cover plate together.

[0027] In one embodiment of the cylindrical battery assembly method of the present invention, the length of the third connecting part is L1, the distance from the end of the second connecting part away from the electrode assembly to the side of the first connecting part facing the cover plate is L2, L1 < L2, and the method further includes;

[0028] The sixth shaping step includes: moving the shaping surface of the shaping fixture along the axial direction of the housing, pressing the third connecting part along the axial direction until the shaping surface abuts against the side wall and the second connecting part.

[0029] In one embodiment of the assembly method of the cylindrical battery of the present invention, the body part includes a protrusion located at the center of the cover plate. The protrusion has a protrusion on the side of the cover plate facing the electrode assembly and a recess on the side of the cover plate away from the electrode assembly. On the cross section through the axis of the cover plate, the side of the connection between the third connecting part and the deformable part facing the electrode assembly is defined as the first bottom end, and the side of the protrusion facing the electrode assembly is defined as the second bottom end. Along the axial direction of the housing, the second bottom end is closer to the electrode assembly than the first bottom end. The method also includes:

[0030] The seventh shaping step includes: pressing down the main body until the second bottom end contacts the first connecting part, and then moving the shaping surface of the shaping fixture along the axial direction of the housing to press the third connecting part along the axial direction until the shaping surface abuts against the side wall.

[0031] The beneficial effects of this invention are as follows: The present invention provides an assembly method for a cylindrical battery. First, the current collector and electrode assembly are welded and fixed to form an electrode assembly. Then, the electrode assembly is installed into the housing. Next, a cover plate is placed in the opening, with the second connecting part clamped between the side wall and the cover plate. Alternatively, the cover plate and the second connecting part abut against each other along the axial direction of the housing, with the outer peripheral surface of the cover plate and the outer peripheral surface of the second connecting part facing the inner wall of the side wall. Both assembly methods ensure that the connecting surfaces of the housing, cover plate, and current collector are flush or nearly flush along the axial direction of the housing, reducing the height of the cover plate and current collector along the axial direction of the housing, saving space occupied by the cover plate and current collector within the housing, and increasing the energy density per unit volume of the cylindrical battery. Attached Figure Description

[0032] 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. In the drawings:

[0033] Figure 1 This is a schematic diagram of the structure of a cylindrical battery according to an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the structure of an electrode assembly provided in one embodiment of the present invention;

[0035] Figure 3 Provided in one embodiment of the present invention Figure 1 A magnified view of a section at point A in the middle;

[0036] Figure 4 This is provided in one embodiment of the present invention. Figure 3 A magnified view of a section at point B in the middle;

[0037] Figure 5 Provided in one embodiment of the present invention Figure 1 A magnified view of a section at point A in the middle;

[0038] Figure 6 Provided in one embodiment of the present invention Figure 5 A magnified view of a section at point C;

[0039] Figure 7 This is provided in one embodiment of the present invention. Figure 1 A magnified view of a section at point A in the middle;

[0040] Figure 8 Provided in one embodiment of the present invention Figure 7 A magnified view of a section at point E in the middle;

[0041] Figure 9 Provided in one embodiment of the present invention Figure 1 A magnified view of a section at point A in the middle;

[0042] Figure 10 Provided in one embodiment of the present invention Figure 9 A magnified view of a section at point F in the middle;

[0043] Figure 11 This is provided in one embodiment of the present invention. Figure 1 A magnified view of a section at point A in the middle;

[0044] Figure 12 Provided in one embodiment of the present invention Figure 11 A magnified view of a section at point G in the middle;

[0045] Figure 13 Provided in one embodiment of the present invention Figure 1 A magnified view of a section at point A in the middle;

[0046] Figure 14 Provided in one embodiment of the present invention Figure 13 A magnified view of a section at point H in the middle;

[0047] Figure 15 Provided in one embodiment of the present invention Figure 1 A magnified view of a section at point A in the middle;

[0048] Figure 16 This is provided in one embodiment of the present invention. Figure 15 A magnified view of a section at point J;

[0049] Figure 17 Provided in one embodiment of the present invention Figure 1 A magnified view of a section at point A in the middle;

[0050] Figure 18 Provided in one embodiment of the present invention Figure 17 A magnified view of a section at point K;

[0051] Figure 19 Provided in one embodiment of the present invention Figure 1 A magnified view of a section at point A in the middle;

[0052] Figure 20 This is provided in one embodiment of the present invention. Figure 19 A magnified view of a section at point M;

[0053] Figure 21 Provided in one embodiment of the present invention Figure 1 A magnified view of a section at point A in the middle;

[0054] Figure 22 Provided in one embodiment of the present invention Figure 21 A magnified view of a portion of point N in the middle;

[0055] Figure 23 Provided in one embodiment of the present invention Figure 1 A magnified view of a section at point A in the middle;

[0056] Figure 24 Provided in one embodiment of the present invention Figure 23 A magnified view of a section at point P in the middle;

[0057] Figure 25 This is a flowchart of an assembly method for a cylindrical battery provided in one embodiment of the present invention;

[0058] Figure 26 This is a flowchart of the assembly method for a cylindrical battery provided in Embodiment 1 of the present invention;

[0059] Figure 27 This is a flowchart of the assembly method for a cylindrical battery provided in Embodiment 2 of the present invention;

[0060] Figure 28 This is a flowchart of the assembly method for the cylindrical battery provided in Embodiment 3 of the present invention;

[0061] Figure 29 This is a flowchart of the assembly method for a cylindrical battery provided in Embodiment 4 of the present invention;

[0062] Figure 30 This is a flowchart of the assembly method for a cylindrical battery provided in Embodiment 5 of the present invention;

[0063] Figure 31 This is a flowchart of the assembly method for a cylindrical battery provided in Embodiment Six of the present invention.

[0064] The attached figures are labeled as follows:

[0065] 100. Cylindrical battery; 110. Casing; 111. End wall; 112. Side wall; 1121. Inner wall of side wall; 113. Opening; 114. First step; 1141. Mating surface; 1142. Inner circumferential surface; 115. Second chamfer; 116. Fifth chamfer; 117. Chamfer; 120. Electrode assembly; 121. First electrode; 1211. Negative current collector; 1212. First coated area; 1213. First uncoated area; 122. Separator; 123. Second electrode; 1231. Positive current collector; 1232. Second coated area; 1233. Second uncoated area; 124. First tab; 125. Second tab; 130. Current collector component; 131 132. First connecting part; 1321. First part; 1322. Second part; 1323. Outer peripheral surface of the second connecting part; 134. First chamfer; 135. Fourth chamfer; 140. Cover plate; 141. Third connecting part; 142. Body part; 1421. Protrusion; 143. Deformable part; 1431. Annular recess; 1432. Annular protrusion; 144. Second step part; 1441. Inclined wall; 1442. Annular surface; 145. Outer peripheral surface of the cover plate; 146. First bottom end; 147. Second bottom end; 148. Third chamfer; 149. Rounded corner; 150. Pole post; 160. Gap; 170. Shaping fixture; 171. Shaping surface. Detailed Implementation

[0066] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention 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 the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0067] 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 the actual implementation. In the 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.

[0068] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the 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 invention.

[0069] Please see Figures 1 to 31 An embodiment of the present invention provides an assembly method for a cylindrical battery 100, the cylindrical battery 100 including a cover plate 140, a current collector 130 and a housing 110. The assembly method makes the mating surfaces of the housing 110, the cover plate 140 and the current collector 130 flush or close to each other along the axial direction of the housing 110, reducing the height of the side wall 112, the cover plate 140 and the current collector 130 along the axial direction of the housing 110, saving the space occupied by the cover plate 140 and the current collector 130 in the housing 110, and improving the energy density per unit volume of the cylindrical battery 100.

[0070] Please see Figure 25 The flowchart of the assembly method shown includes: a first assembly step S1, including: S1a, providing an electrode assembly 120, the electrode assembly 120 including a tab disposed at one end.

[0071] Please see Figure 1 and Figure 2 Electrode assembly 120 is the component in cylindrical battery 100 where electrochemical reactions occur. Electrode assembly 120 includes a wound structure formed by stacking and winding a first electrode 121, a second electrode 123, and a separator 122. The first electrode 121 and the second electrode 123 have opposite polarities. In some embodiments, the first electrode 121 is a positive electrode and the second electrode 123 is a negative electrode. In other embodiments, the first electrode 121 is a negative electrode and the second electrode 123 is a positive electrode.

[0072] Please see Figure 2In this embodiment, the first electrode 121 is a negative electrode. The first electrode 121 includes a negative current collector 1211 and a negative active material. The negative active material is coated on the surface of the negative current collector 1211. The negative current collector 1211 includes a first coated area 1212 coated with active material and a first uncoated area 1213 uncoated with active material. The first uncoated area 1213 is located at the end of the first electrode 121. The first uncoated area 1213 extends out of the diaphragm 122 along the winding axis of the electrode assembly 120 to form an electrode tab. In order to distinguish the electrode tab formed by the second electrode 123, the electrode tab located on the first electrode 121 is called the first electrode tab 124. The first electrode tab 124 is the corresponding negative electrode tab. The second electrode 123 is a positive electrode. Specifically, the second electrode 123 includes a positive current collector 1231 and a positive active material, with the positive active material coated on the surface of the positive current collector 1231. The positive current collector 1231 includes a second coated area 1232 coated with active material and a second uncoated area 1233 uncoated with active material. The second uncoated area 1233 is located at the end of the second electrode 123. The other end of the second uncoated area 1233 extends out of the diaphragm 122 along the winding axis of the electrode assembly 120 and is bent toward the winding axis to form a second tab 125, which is the corresponding positive tab. The diaphragm 122 is disposed between the first electrode 121 and the second electrode 123 to isolate the positive active material layer and the negative active material layer. In this embodiment, the first tab 124 is electrically connected to the housing 110, making the housing 110 negatively charged, and the second tab 125 is electrically connected to the electrode post 150, making the electrode post 150 positively charged.

[0073] The first assembly step S1 also includes: S1b, providing the manifold component 130. (See also...) Figure 3 The current collector 130 includes a first connecting portion 131 and a second connecting portion 132, with the second connecting portion 132 surrounding the outer periphery of the first connecting portion 131. The form of the second connecting portion 132 is not limited; it can be a completely closed surrounding type or a type in which multiple pins are spaced around the first connecting portion 131 in a circumferential manner.

[0074] The first assembly step S1 further includes: S1c, welding and fixing the first connecting part 131 to the electrode tab to form an electrode assembly assembly. The welding method can be ultrasonic welding, resistance welding, laser welding, etc., and is not limited thereto. In this embodiment, laser welding is used. After welding, the second connecting part 132 and the electrode assembly 120 are respectively located on both sides of the first connecting part 131. The second connecting part 132 is used to weld and connect with the housing 110 and / or the cover plate 140 to realize the electrical connection between the electrode assembly 120 and the housing 110.

[0075] Please continue reading. Figure 25The flowchart of the assembly method shown includes a second assembly step S2, which includes: S2a, providing the housing 110.

[0076] Please see Figure 1 The housing 110 includes a surrounding sidewall 112, at least one end of which has an opening 113. A receiving cavity is formed circumferentially around the sidewall 112. The receiving cavity is used to receive the electrode assembly 120, electrolyte (not shown), and other components. The housing 110 is axially (e.g., Figure 1 The housing 110 (shown as O to O1) has at least one opening 113 at both ends, and a cover plate 140 seals at least one opening 113. In one embodiment, the housing 110 has openings 113 at opposite ends of the receiving cavity, and the two openings 113 are respectively closed by an end cap. In this embodiment, the housing 110 has an opening 113 at one end of the receiving cavity, and an end wall 111 integrally formed with the surrounding side wall 112 at the other end of the receiving cavity. The end wall 111 and the side wall 112 are integrally stamped or integrally cast. The circumference of the side wall 112 is not limited and can be cylindrical, cuboid, or prismatic, or can be along any other closed-loop contour that can match the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 112 is cylindrical and surrounds the outer edge of the end wall 111, with a circular opening 113 formed at the end of the side wall 112 opposite to the end wall 111.

[0077] The second assembly step S2 further includes: S2b, installing the electrode assembly assembly into the housing 110 through the opening 113; S2c, providing a cover plate 140 and placing the cover plate 140 in the opening 113.

[0078] The shape of the cover plate 140 is adapted to the opening 113 to achieve a seal between the cover plate 140 and the opening 113. In this embodiment, the opening 113 in the housing 110 is circular, so the outer periphery of the cover plate 140 is also circular. In one embodiment, please refer to... Figures 13 to 24 The second connecting portion 132 is clamped between the side wall 112 and the cover plate 140. The mating surfaces connecting the housing 110, the cover plate 140, and the flow-collecting member 130 are flush or substantially flush along the axial direction of the housing 110. In another embodiment, please refer to... Figures 3 to 12The cover plate 140 and the second connecting portion 132 abut against the housing 110 in the axial direction. The outer peripheral surface 145 of the cover plate 140 and the outer peripheral surface 1323 of the second connecting portion 132 are opposite to the inner wall 1121 of the side wall 112. At this time, the mating surfaces connecting the housing 110, the cover plate 140, and the current collector 130 approach each other along the axial direction of the housing 110. Both of the above embodiments reduce the height of the cover plate 140 and the current collector 130 along the axial direction of the housing 110, saving the space occupied by the cover plate 140 and the current collector 130 within the housing 110 and increasing the energy density per unit volume of the cylindrical battery 100.

[0079] The following description will elaborate on six examples.

[0080] Example 1

[0081] Please see Figures 3 to 6 and Figure 26 In an embodiment of the assembly method of the cylindrical battery 100 of the present invention, the sidewall 112 includes a first stepped portion 114 disposed at one end near the cover plate 140. The first stepped portion 114 includes a mating surface 1141 facing the cover plate 140 and an inner peripheral surface 1142 surrounding the mating surface 1141. The second connecting portion 132 includes a first portion 1321 and a second portion 1322. The second portion 1322 extends radially from the inside to the outside along the cover plate 140. The first portion 1321 connects the second portion 1322 and the first connecting portion 131. A portion of the second portion 1322 overlaps with the mating surface 1141. At this time, the outer peripheral surface 1323 of the second connecting portion 132 is the outer peripheral surface of the second portion 1322. The diameter of the outer peripheral surface of the second portion 1322 is D1, and the diameter of the inner peripheral surface 1142 is D2, where D1 < D2. Figure 4 As shown. Setting D1 < D2 facilitates the insertion of the electrode assembly into the housing. If D1 > D2, the electrode assembly needs to be inserted into the housing with the help of the tooling of the outwardly expanding opening 113, which makes the assembly difficult and carries the risk of metal shavings being generated by friction with the housing 110.

[0082] Please see Figure 5 and Figure 6 The cover plate 140 has a second step portion 144 on the outer periphery facing the electrode assembly 120. The second step portion 144 includes an inclined wall 1441 and an annular surface 1442 connected to the radially outer end of the inclined wall 1441. The annular surface 1442 faces the second part 1322 and contacts the second part 1322. The inclined wall 1441 faces the first part 1321 and presses against the first part 1321.

[0083] Please see Figure 5 , Figure 6 and Figure 26Following the second assembly step S2, the assembly method further includes a first shaping step S3-1, comprising: pressing down the cover plate 140 along the axial direction of the housing 110; the inclined wall 1441 of the cover plate 140 pressing down on the first part 1321 of the current collecting member 130; the first part 1321 expanding outward along the radial outer side of the cover plate 140, so that the outer peripheral surface of the second part 1322 abuts against the inner wall 1121 of the side wall 112. Thanks to the above-mentioned structural arrangement of the cover plate 140, the current collecting member 130 is shaped, allowing the outer peripheral surface of the second part 1322 to abut against the inner wall 1121 of the side wall 112 during the pressing down of the cover plate 140, which further facilitates the welding of the second connecting part 132 and the inner wall of the side wall 112, ensuring welding quality.

[0084] Please see Figure 5 , Figure 6 and Figure 26 The assembly method also includes a first welding step S4-1, which involves welding the sidewall 112, the second connecting portion 132, and the cover plate 140 together. This welding process uses a single laser seam weld to fix the second connecting portion 132, the cover plate 140, and the sidewall 112. This welding method simplifies the welding process and improves welding efficiency. Furthermore, since the laser welding position is located above the cover plate 140 and a seam weld is used, the mating surface 1141 faces the cover plate 140, which can prevent heat from being transferred into the housing 110, thereby reducing the thermal impact of welding heat on the electrode assembly 120.

[0085] To reduce the difficulty of fitting the electrode assembly assembly and cover plate 140 into the housing, and to further alleviate the problem of metal shavings generated by friction between the electrode assembly assembly and cover plate 140 and the housing 110, please refer to... Figure 7 and Figure 8 In the first embodiment of the assembly method of the cylindrical battery 100 of the present invention, the edge of the second connecting portion 132 facing the electrode assembly 120 forms a first chamfer 134; and / or, the radial inner edge of the opening 113 forms a second chamfer 115; and / or, the edge of the cover plate 140 facing the electrode assembly 120 forms a third chamfer 148.

[0086] Please see Figure 7 and Figure 8Specifically, in one embodiment, the current collector 130 is stamped, and when the current collector 130 is blanked, the stamping direction is from the side of the current collector 130 facing the electrode assembly 120 to the side away from the electrode assembly 120, so that a chamfer can be formed on the edge of the second connecting portion 132 facing the electrode assembly 120, which is the first chamfer 134. The housing 110 is stamped, and the end face of the opening 113 is cut from the radially inner side to the radially outer side, so that a chamfer can be formed on the inner edge of the opening 113, which is the second chamfer 115. The cover plate 140 is stamped, and when the cover plate 140 is blanked, the stamping direction is from the side of the cover plate 140 facing the electrode assembly 120 to the side away from the electrode assembly 120, so that a chamfer can be formed on the edge of the cover plate 140 facing the electrode assembly 120, which is the third chamfer 148. In some other embodiments, the first chamfer 134, the second chamfer 115, and the third chamfer 148 can also be obtained by machining. The first chamfer 134, the second chamfer 115 and the third chamfer 148 can also serve as assembly guides. In addition, after the shell 110, the cover plate 140 and the flow collector 130 are unloaded, the burrs face outward in the same direction, which can prevent the burrs from falling into the shell 110 and causing safety hazards.

[0087] Example 2

[0088] Please see Figures 9 to 12 and Figure 27 In the second embodiment of the assembly method of the cylindrical battery 100 of the present invention, the outer peripheral surface 145 of the cover plate 140 and the side wall 112 are opposite to each other and have a gap 160. The outer peripheral surface 1323 of the second connecting part 132 abuts against the side wall 112. The edge of the cover plate 140 away from the electrode assembly 120 is provided with a rounded corner 149, and the radially inner edge of the opening 113 is provided with a chamfer 117.

[0089] Please see Figure 9 , Figure 10 and Figure 27 Following the second assembly step S2, the assembly method further includes a second welding step S3-2, which involves laser welding through the gap 160 to connect the second connecting part 132 and the side wall 112. This welding step can be a full weld or a partial spot weld, as long as the electrical connection between the second connecting part 132 and the side wall 112 is achieved, and the shape and position of the welded part are not limited.

[0090] Please see Figure 11 and Figure 12The assembly method further includes a third shaping step S4-2, which involves rolling one end of the opening 113 of the housing 110 so that the housing 110 covers the outer peripheral surface 145 of the cover plate 140. This shaping step can reduce the gap 160 between the cover plate 140 and the housing 110, which is beneficial for welding. In addition, the rounded corners 149 and chamfers 117 make the housing 110 and the cover plate 140 as tangent as possible after rolling, reducing the gap 160, and making the housing 110 fit more closely to the molten pool generated by the welding in the second welding step S3-2, avoiding the presence of a gap 160 after rolling the housing 110, which could cause a blowout.

[0091] The assembly method also includes a third welding step S5-2, which includes welding the cover plate 140 and the side wall 112 together to seal the opening 113 of the cover plate 140.

[0092] In one example, before the second welding step S3-2 and after the second assembly step S2, the method further includes: a first shaping step S3-1, comprising: pressing down the cover plate 140 along the axial direction of the housing 110, the inclined wall 1441 of the cover plate 140 pressing the first portion 1321 of the collector member 130, the first portion 1321 expanding outward along the radially outer side of the cover plate 140 so that the outer peripheral surface of the second portion 1322 abuts against the inner wall 1121 of the side wall 112.

[0093] Example 3

[0094] Please see Figures 13 to 16 and Figure 28 In one embodiment of the assembly method of the cylindrical battery 100 of the present invention, the second connecting portion 132 extends in a direction away from the electrode assembly 120, and the outer peripheral surface 1323 of the second connecting portion 132 is transitionally fitted or interference-fitted with the inner wall 1121 of the side wall 112. The second connecting portion 132 is sandwiched between the side wall 112 and the cover plate 140. At this time, the mating surfaces connecting the housing 110, the cover plate 140, and the current collector 130 are flush along the axial direction of the housing 110. This reduces the height of the cover plate 140 and the current collector 130 along the axial direction of the housing 110, saves the space occupied by the cover plate 140 and the current collector 130 in the housing 110, and improves the energy density per unit volume of the cylindrical battery 100.

[0095] Please see Figure 16In one embodiment of the assembly method of the cylindrical battery 100 of the present invention, the cover plate 140 includes a body portion 142, a deformable portion 143 and a third connecting portion 141. The body portion 142 is located at the center of the cover plate 140. On a cross section passing through the axis of the cover plate 140, one end of the deformable portion 143 is connected to the third connecting portion 141 and the other end is connected to the body portion 142. The third connecting portion 141 extends in a direction away from the electrode assembly 120. An annular recess 1431 is formed on the side of the deformable portion 143 facing the electrode assembly 120, and an annular protrusion 1432 is formed on the side of the deformable portion 143 away from the electrode assembly 120.

[0096] Please see Figure 13 and Figure 14 Following the second assembly step S2, the assembly method further includes a fourth shaping step S3-3, which includes pressing down the deformable portion 143 along the axial direction of the housing 110. The deformable portion 143 pushes the third connecting portion 141 to move radially outward toward the cover plate 140, thereby squeezing the second connecting portion 132 to tilt radially outward toward the cover plate 140, so that the outer peripheral surface 1323 of the second connecting portion 132 and the inner wall 1121 of the side wall 112 have a transition fit or interference fit. It should be noted that before the cover plate 140 is pressed down, there is an installation gap between the outer peripheral surface 1323 of the second connecting portion 132 and the inner wall 1121 of the side wall 112. The diameter of the outer peripheral edge of the second connecting portion 132 is defined as D3, and the diameter of the inner wall is defined as D4, where D3 < D4. Figure 14 As shown. Setting D3 < D4 facilitates the insertion of the electrode assembly into the housing. If D3 > D4, the electrode assembly needs to be inserted into the housing with the help of the tooling of the outwardly expanding opening 113, which makes the assembly difficult and carries the risk of metal shavings being generated by friction with the housing 110.

[0097] Considering that the second connecting portion 132 will tilt radially outward towards the cover plate 140 under the push of the deformed portion 143, in order to better fit the side wall 112 with the tilted second connecting portion 132, a thinning portion 118 is provided at one end of the inner wall 1121 of the side wall 112 near the cover plate 140. The thinning portion 118 has a radial thickness reduction along the housing 110. The bottom end of the thinning portion 118 along the axial direction of the housing 110 includes an annular arc surface 1181. The bottom end of the second connecting portion 132 abuts against the annular arc surface 1181 to restrict the movement of the second connecting portion 132 toward the electrode assembly 120. This facilitates the alignment or near-alignment of the end of the second connecting portion 132 away from the electrode assembly 120, the end of the cover plate 140 away from the electrode assembly 120, and the end of the side wall 112 away from the electrode assembly 120, thereby achieving consistent laser focus, which is beneficial for energy absorption and thus improves welding quality.

[0098] The assembly method also includes a first welding step S4-3, which involves welding the side wall 112, the second connecting portion 132, and the cover plate 140 together. This welding process uses a single laser seam weld to fix the second connecting portion 132, the cover plate 140, and the side wall 112. This welding method simplifies the welding process and improves welding efficiency. Furthermore, since the laser welding position is located above the cover plate 140 and a seam weld is used, the mating surface 1141 faces the cover plate 140, which can block heat transfer into the housing 110, thereby reducing the thermal impact of welding heat on the electrode assembly 120.

[0099] Please see Figure 17 and Figure 18 To reduce the difficulty of inserting the electrode assembly assembly and cover plate 140 into the casing, and to further alleviate the problem of metal shavings generated by friction between the electrode assembly assembly and cover plate 140 and the casing 110, in one embodiment of the assembly method of the cylindrical battery 100 of the present invention, a fourth chamfer 135 is formed on the radially inner edge of the second connecting portion 132; and / or, a fifth chamfer 116 is formed on the radially inner edge of the opening 113.

[0100] Specifically, in one embodiment, the current collector 130 is stamped and formed. During blanking, the stamping direction of the current collector 130 is from the side of the current collector 130 away from the electrode assembly 120 towards the side facing the electrode assembly 120. Then, the second connecting portion 132 is bent away from the electrode assembly 120 to form a chamfer, i.e., a fourth chamfer 135, on the radially inner edge of the second connecting portion 132. The housing 110 is stamped and formed, and the end face of the opening 113 is cut from the radially inner to the radially outer side to form a chamfer, i.e., a fifth chamfer 116, on the inner edge of the opening 113. In some other embodiments, the fourth chamfer 135 and the fifth chamfer 116 can also be obtained by machining. The fourth chamfer 135 and the fifth chamfer 116 can also serve as assembly guides. Furthermore, after blanking, the burrs of the housing 110, cover plate 140, and current collector 130 all point outwards, preventing burrs from falling into the housing 110 and causing safety hazards.

[0101] Example 4

[0102] Please see Figures 19 to 24 and Figure 29In one embodiment of the assembly method of the cylindrical battery 100 of the present invention, the second connecting part 132 is clamped between the side wall 112 and the cover plate 140. After the second assembly step S2, the assembly method further includes: a fifth shaping step S3-4, including: the shaping surface 171 of the shaping fixture 170 moves along the axial direction of the housing 110, pressing the cover plate 140 to move along the axial direction until the shaping surface 171 abuts against the side wall 112. This shaping step is performed by the shaping fixture 170, completing the one-time assembly of the current collector 130 and the cover plate 140, simplifying the positioning process, and thus improving assembly efficiency and quality.

[0103] The first welding step S4-4 includes welding the side wall 112, the second connecting part 132 and the cover plate 140 together.

[0104] In one example, after performing the second assembly step S2 and before the fifth shaping step S3-4, the method further includes: a fourth shaping step S3-3, which includes pressing down the deformable portion 143 along the axial direction of the housing 110, the deformable portion 143 pushing the third connecting portion 141 to move radially outward toward the cover plate 140 to compress the second connecting portion 132 to tilt radially outward toward the cover plate 140 so that the outer peripheral surface 1323 of the second connecting portion 132 transition fits or interference fits with the inner wall 1121 of the side wall 112.

[0105] Example 5

[0106] Please see Figures 19 to 22 and Figure 30 In one embodiment of the assembly method of the cylindrical battery 100 of the present invention, the length of the third connecting portion 141 is L1, and the distance from one end of the second connecting portion 132 away from the electrode assembly 120 to the side of the first connecting portion 131 facing the cover plate 140 is L2, where L1 < L2. Please refer to [link to relevant documentation]. Figure 24 This configuration ensures that after the cover plate 140 is in place, the end of the third connecting portion 141 of the cover plate 140 near the electrode assembly 120 does not contact the current collector 130, forming a clearance to avoid the accumulation of height tolerances. This also helps to make the end of the cover plate 140 away from the electrode assembly 120, the end of the second connecting portion 132 away from the electrode assembly 120, and the end of the side wall 112 away from the electrode assembly 120 flush.

[0107] The assembly method further includes a sixth shaping step S3-5, which involves moving the shaping surface 171 of the shaping fixture 170 along the axial direction of the housing 110, pressing the third connecting portion 141 along the axial direction until the shaping surface 171 abuts against the side wall 112 and the second connecting portion 132. In this shaping step, the shaping fixture 170 presses down on the cover plate 140. The shaping surface 171 first contacts one end of the cover plate 140 away from the electrode assembly 120, and then contacts one end of the second connecting portion 132 away from the electrode assembly 120, until the pressure plate contacts one end of the side wall 112 away from the electrode assembly 120, so that one end of the cover plate 140 away from the electrode assembly 120, one end of the second connecting portion 132 away from the electrode assembly 120, and one end of the side wall 112 away from the electrode assembly 120 are flush. At this time, the laser focus is consistent, which is beneficial for energy absorption and thus improves the welding quality.

[0108] In one example, the sixth shaping step S3-5 is performed after the fourth shaping step S3-3 in Embodiment 3 to facilitate the insertion of the electrode assembly into the housing. After the sixth shaping step S3-5 is completed, the first welding step S4-5 is performed, which includes welding the sidewall 112, the second connecting part 132 and the cover plate 140 together.

[0109] Example 6

[0110] Please see Figures 19 to 20 , Figures 23 to 24 and Figure 31 In one embodiment of the assembly method of the cylindrical battery 100 of the present invention, the body portion 142 includes a protrusion 1421 located at the center of the cover plate 140. The protrusion 1421 has a protrusion on the side of the cover plate 140 facing the electrode assembly 120 and a recess on the side of the cover plate 140 away from the electrode assembly 120. On the cross section through the axis of the cover plate 140, the side of the connection between the third connecting portion 141 and the deformable portion 143 facing the electrode assembly 120 is defined as the first bottom end 146, and the side of the protrusion 1421 facing the electrode assembly 120 is defined as the second bottom end 147. Along the axial direction of the housing 110, the second bottom end 147 is closer to the electrode assembly 120 than the first bottom end 146.

[0111] The assembly method further includes: a seventh shaping step S3-6, comprising: pressing down the main body 142 until the second bottom end 147 contacts the first connecting part 131, and then moving the shaping surface 171 of the shaping fixture 170 along the axial direction of the housing 110 to press the third connecting part 141 along the axial direction until the shaping surface 171 abuts against the side wall 112. The difference between this embodiment and embodiment 5 is that, on the cross-section through the axis of the cover plate 140, the distance from the upper end face of the second connecting part 132 to the upper end face of the third connecting part 141 is L3, and the distance between the first bottom end 146 and the second bottom end 147 is L4, where L3 > L4. Please refer to [link / reference needed]. Figure 24 This configuration allows the end of the second connecting portion 132 furthest from the electrode assembly 120 to be slightly lower than the end of the third connecting portion 141 facing away from the electrode assembly 120 after the cover plate 140 is in place. At this time, the second connecting portion 132, the housing 110, and the cover plate 140 form an annular groove, which facilitates the formation of a weld pool and improves the strength and reliability of the weld.

[0112] In one example, the seventh shaping step S3-6 is performed after the fourth shaping step S3-3 in Embodiment 3 to facilitate the insertion of the electrode assembly into the housing. After the seventh shaping step S3-6 is completed, the first welding step S4-6 is performed, which includes welding the sidewall 112, the second connecting part 132 and the cover plate 140 together.

[0113] This invention proposes an assembly method for a cylindrical battery, in which the second connecting part is clamped between the side wall and the cover plate, or the cover plate and the second connecting part abut against each other in the axial direction of the housing, with the outer peripheral surface of the cover plate and the outer peripheral surface of the second connecting part facing the inner wall of the side wall. Both assembly methods ensure that the mating surfaces connecting the housing, cover plate, and current collector are flush or nearly flush along the axial direction of the housing, reducing the height of the cover plate and current collector along the axial direction of the housing, saving the space occupied by the cover plate and current collector within the housing, and increasing the energy density per unit volume of the cylindrical battery.

[0114] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for assembling a cylindrical battery, characterized in that, include: The first assembly step includes: providing an electrode assembly, the electrode assembly including a tab disposed at one end; providing a current collector, the current collector including a first connecting portion and a second connecting portion, the second connecting portion being disposed around the outer periphery of the first connecting portion; welding and fixing the first connecting portion to the tab to form an electrode assembly, the second connecting portion and the electrode assembly being located on both sides of the first connecting portion; The second assembly step includes: providing a housing, the housing including a surrounding sidewall, at least one end of the sidewall having an opening; installing the electrode assembly into the housing through the opening; providing a cover plate and placing the cover plate in the opening such that the second connecting portion is clamped between the sidewall and the cover plate, or the cover plate and the second connecting portion abut against each other in the axial direction of the housing, the outer peripheral surface of the cover plate and the outer peripheral surface of the second connecting portion are both opposite to the inner wall of the sidewall.

2. The assembly method according to claim 1, characterized in that, The sidewall includes a first stepped portion disposed at one end near the cover plate. The first stepped portion includes a mating surface facing the cover plate and an inner circumferential surface surrounding the mating surface. The second connecting portion includes a first part and a second part. The second part extends radially from the inside to the outside along the cover plate. The first part connects the second part and the first connecting portion. A portion of the second part overlaps the mating surface. The cover plate has a second step portion on the outer periphery facing the electrode assembly. The second step portion includes an inclined wall and an annular surface connected to the radially outer end of the inclined wall. The annular surface faces the second part and contacts the second part. The inclined wall faces the first part and presses against the first part. After the second assembly step, the method further includes: The first shaping step includes: pressing the cover plate down along the axial direction of the housing, the inclined wall of the cover plate pressing the first part of the flow collecting member, the first part expanding outward along the radial outer side of the cover plate so that the outer peripheral surface of the second part abuts against the inner wall of the side wall; The first welding step includes welding the sidewall, the second connecting part, and the cover plate together.

3. The assembly method according to claim 2, characterized in that, The edge of the second connecting portion facing the electrode assembly forms a first chamfer; and / or, The radially inner edge of the opening is formed with a second chamfer; and / or, The edge of the cover plate facing the electrode assembly has a third chamfer.

4. The assembly method according to claim 1, characterized in that, The outer peripheral surface of the cover plate and the side wall are opposite to each other with a gap. The outer peripheral surface of the second connecting part abuts against the side wall. The edge of the cover plate opposite to the electrode assembly is provided with a rounded corner, and the radially inner edge of the opening is provided with a chamfer. After the second assembly step, the method further includes: The second welding step includes: using a laser to weld the second connecting part and the sidewall together through the gap; The third shaping step includes: rolling one end of the opening of the housing to make the housing cover the outer peripheral surface of the cover plate; The third welding step includes welding the cover plate and the side wall together.

5. The assembly method according to claim 1, characterized in that, The second connecting portion extends in a direction away from the electrode assembly, and the outer peripheral surface of the second connecting portion is transition-fitted or interference-fitted with the inner wall of the side wall. The second connecting portion is clamped between the side wall and the cover plate.

6. The assembly method according to claim 5, characterized in that, The cover plate includes a body portion, a deformable portion, and a third connecting portion. The body portion is located at the center of the cover plate. On a cross section passing through the axis of the cover plate, one end of the deformable portion is connected to the third connecting portion, and the other end is connected to the body portion. The third connecting portion extends in a direction away from the electrode assembly. An annular recess is formed on the side of the deformable portion facing the electrode assembly, and an annular protrusion is formed on the side of the deformable portion away from the electrode assembly. After the second assembly step, the method further includes: The fourth shaping step includes pressing the deformable part downward along the axial direction of the housing, the deformable part pushing the third connecting part to move radially outward toward the cover plate, so as to compress the second connecting part to tilt radially outward toward the cover plate, so that the outer peripheral surface of the second connecting part transitions or interferes with the inner wall of the side wall; The first welding step includes welding the sidewall, the second connecting part, and the cover plate together.

7. The assembly method according to claim 5 or 6, characterized in that, The radially inner edge of the second connecting portion forms a fourth chamfer; and / or, The radially inner edge of the opening has a fifth chamfer.

8. The assembly method according to claim 1, characterized in that, The second connecting portion is clamped between the side wall and the cover plate, and the method further includes: The fifth shaping step includes: the shaping surface of the shaping fixture moves along the axial direction of the housing and presses against the cover plate as it moves along the axial direction until the shaping surface abuts against the side wall; The first welding step includes welding the sidewall, the second connecting part, and the cover plate together.

9. The assembly method according to claim 6, characterized in that, The length of the third connecting part is L1, and the distance from the end of the second connecting part away from the electrode assembly to the side of the first connecting part facing the cover plate is L2, where L1 < L2. The method further includes: The sixth shaping step further includes: moving the shaping surface of the shaping fixture along the axial direction of the housing to press the third connecting part along the axial direction until the shaping surface abuts against the side wall and the second connecting part.

10. The assembly method according to claim 6, characterized in that, The body portion includes a protrusion located at the center of the cover plate. The protrusion forms a raised portion on the side of the cover plate facing the electrode assembly, and a recess forms a recess on the side of the cover plate away from the electrode assembly. On a cross section through the axis of the cover plate, the side of the connection between the third connecting portion and the deformable portion facing the electrode assembly is defined as the first bottom end, and the side of the protrusion facing the electrode assembly is defined as the second bottom end. Along the axial direction of the housing, the second bottom end is closer to the electrode assembly than the first bottom end. The method further includes: The seventh shaping step further includes: pressing down the main body until the second bottom end contacts the first connecting part, and then moving the shaping surface of the shaping fixture along the axial direction of the housing to press the third connecting part along the axial direction until the shaping surface abuts against the side wall.

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