Collecting member of secondary battery and assembling method of secondary battery

Abstract

The invention provides a current collecting member of a secondary battery and an assembling method of the secondary battery. The current collecting component comprises a current collecting body and a plurality of pins, the current collector body is used for connecting an electrode assembly; the plurality of pins are arranged on the periphery of the current collecting body at intervals, each pin comprises a shell welding part and a connecting part for connecting the shell welding part and the periphery of the current collecting body, and the shell welding part is used for connecting a shell; on the vertical section, passing through the pins, of the current collecting component, the current collecting body extends in the horizontal direction and comprises the outermost end, the shell welding part extends in the vertical direction and comprises the bottommost end, the height difference exists between the bottommost end of the shell welding part and the outermost end of the current collecting body in the vertical direction, and the connecting part is connected with the outermost end and the bottommost end along a straight line or an arc line. The overall width of the connecting part in the horizontal direction is L, the radius of the electrode assembly is R, 5 < = R / L < = 20, the overall height of the connecting part in the vertical direction is H, 2 < = L / H < = 20, and therefore the technical problem that after the current collecting component is bent, the electrode assembly is pressed and damaged is solved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically to a current collector for a secondary battery and a method for assembling a secondary battery. Background Technology

[0002] Mechanical sealing is the mainstream packaging method for existing cylindrical batteries. It is widely used due to its advantages of mature technology and equipment and fast production cycle. In existing cylindrical batteries, a current collector is usually set near the opening of the casing. One end of the current collector is welded to the side wall of the casing, and the other end is electrically connected to the electrode assembly, thereby realizing the electrical connection between the casing and the electrode assembly, and then mechanical sealing is performed.

[0003] Mechanical sealing involves rolling grooves that are recessed towards the inside of the housing onto the side wall of the housing, and then pressing the cover plate tightly by a pressing method. During the grooving process, the current collector will bend as the groove deforms. Due to the limited space between the groove and the electrode assembly, the bent pins are prone to move towards the electrode assembly, thereby damaging the electrode assembly. Summary of the Invention

[0004] This invention provides a current collector for a secondary battery and an assembly method for the secondary battery, in order to improve the technical problem of the current collector damaging the electrode assembly due to bending.

[0005] To achieve the above and other related objectives, the present invention provides a current collector component for a secondary battery and an assembly method for the secondary battery. The current collector component of the secondary battery includes a current collector body and multiple pins; the current collector body is used to connect an electrode assembly; the multiple pins are spaced apart on the outer periphery of the current collector body, each pin including a housing welding portion and a connecting portion connecting the housing welding portion and the outer periphery of the current collector body, the housing welding portion being used to connect the housing; the thickness direction of the current collector body is defined as the vertical direction, and the direction perpendicular to the vertical direction is defined as the horizontal direction. On a vertical cross-section of the current collector component passing through the pins along the vertical direction, the current collector body extends horizontally and includes an outermost end, the housing welding portion extends vertically and includes a bottommost end, the bottommost end of the housing welding portion and the outermost end of the current collector body have a height difference along the vertical direction, the connecting portion connects the outermost end and the bottommost end along a straight line or an arc, the overall height of the connecting portion along the vertical direction is H, the overall width of the connecting portion along the horizontal direction is L, the radius of the electrode assembly is R, where 5≤R / L≤20, and the overall height of the connecting portion along the vertical direction is H, where 2≤L / H≤20.

[0006] In one example of the current collector component of the secondary battery of the present invention, the overall width L of the connecting part in the horizontal direction ranges from 5mm ≥ L ≥ 2.5mm, and the overall height H of the connecting part in the vertical direction ranges from 3.55mm ≥ H ≥ 0.7mm.

[0007] In one example of the current collector component of the secondary battery of the present invention, the connecting part includes an arc body that connects the outer periphery of the housing welding part and the current collector body, and the arc body is arc-shaped in the vertical cross section.

[0008] In one example of the current collector of the secondary battery of the present invention, the radius of the outer wall of the arc is R, wherein 3.55mm≥R≥0.7mm.

[0009] In one example of the current collector component of the secondary battery of the present invention, the connecting part includes a single-section planar body or multiple sections of planar body connected end to end. The planar body is straight in the vertical cross section. The plane passing through the bottom side of the current collector body and perpendicular to the vertical direction is defined as the horizontal plane. There is an angle between the planar body and the horizontal plane.

[0010] In one example of the current collector of the secondary battery of the present invention, the overall height of the planar body in the vertical direction is a, wherein 3.55mm ≥ a ≥ 0.7mm.

[0011] In one example of the current collector component of the secondary battery of the present invention, the pin includes a bent guide portion disposed in the connection portion.

[0012] In one example of the current collector of the secondary battery of the present invention, the bending guide includes a buffer hole that penetrates through the thickness direction of the connecting part and extends circumferentially along the current collector.

[0013] In one example of the current collector of the secondary battery of the present invention, the bending guide includes a weak part provided in the connecting part, and the weak part is subjected to material thickness reduction treatment.

[0014] The present invention also provides a method for assembling a secondary battery. The secondary battery includes a casing, an electrode assembly, and a cover plate. The casing includes a surrounding sidewall, one end of which has an opening. The assembly method includes the following steps:

[0015] This invention provides a flow collector component;

[0016] The current collector body of the current collector component is welded to the current collector part of the electrode assembly to form the cell assembly part;

[0017] Install the cell assembly into the housing through the opening, with the current collector facing the opening;

[0018] The pins of the current collector are overlapped with the side wall of the housing, forming a solderable area between them.

[0019] Solder the area to be soldered to form a solder joint between the pin and the sidewall;

[0020] Rolling is performed on the side wall area corresponding to the weld to form a groove, and the groove restricts the axial displacement of the current collector and the electrode assembly.

[0021] The cover plate is installed on the side of the groove away from the electrode assembly to seal the opening.

[0022] In one example of the assembly method of the secondary battery of the present invention, in the step of rolling the side wall area corresponding to the welding part to form a groove and restricting the axial displacement of the electrode assembly by the groove: the connecting part of the current collector is bent to form a curved structure, and the maximum distance between the bottom end of the curved structure facing the electrode assembly and the first plane is greater than or equal to 0 and less than or equal to 2.5 mm. The electrode assembly includes an electrode body and a current collector stacked on the end face of the electrode body facing the opening. The first plane is the plane where the end face of the electrode body is located.

[0023] The present invention discloses a current collector component for a secondary battery, comprising a current collector body and a plurality of pins spaced apart and connected to the current collector body. Each pin includes a connecting portion connected to the current collector body and a housing weld portion for connecting to a housing. The bottom end of the housing weld portion and the outermost end of the current collector body have a vertical height difference, and the connecting portion connects the outermost and bottom ends along a straight line or arc. The overall width of the connecting portion in the horizontal direction is L, the radius of the electrode assembly is R, where 5 ≤ R / L ≤ 20, and the overall height of the connecting portion in the vertical direction is H, where 2 ≤ L / H ≤ 20. By limiting the ratios R / L and L / H to the above ranges, the connecting portion can have a suitable degree of deformability, while simultaneously forming a deformation space matching the aforementioned degree of deformability. This mitigates the problem of excessive downward deformation caused by excessive deformation of the connecting portion itself or excessive deformation space requirements during the rolling process, which could lead to pressure on the electrode assembly and subsequent damage or failure of the electrode assembly. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of an embodiment of the current collection component of the present invention;

[0026] Figure 2 This is a cross-sectional view of an embodiment of the current collection component of the present invention;

[0027] Figure 3 for Figure 2 A magnified view of a section at point A in the middle;

[0028] Figure 4 for Figure 2 A magnified view of a section at point A in the middle;

[0029] Figure 5 This is a cross-sectional view of an embodiment of the current collection component of the present invention;

[0030] Figure 6 for Figure 5 A magnified view of a section at point B in the middle;

[0031] Figure 7 for Figure 5 A magnified view of a section at point B in the middle;

[0032] Figure 8 This is a schematic diagram of the structure of an embodiment of the current collection component of the present invention;

[0033] Figure 9 This is a cross-sectional view of an embodiment of the current collection component of the present invention;

[0034] Figure 10 This is a cross-sectional view of an embodiment of the current collection component of the present invention;

[0035] Figure 11 This is a schematic diagram of the structure before the grooving in one embodiment of the secondary battery of the present invention;

[0036] Figure 12 for Figure 11 A partial enlarged view of an embodiment at point C;

[0037] Figure 13 for Figure 12 A partial enlarged view of an embodiment at point D;

[0038] Figure 14 This is a schematic diagram of the structure of a secondary battery according to an embodiment of the present invention;

[0039] Figure 15 This is a schematic diagram of the electrode assembly structure of an embodiment of the secondary battery of the present invention;

[0040] Figure 16 for Figure 14 A partial enlarged view of an embodiment at point E;

[0041] Figure 17 for Figure 14 A partial enlarged view of an embodiment at point E;

[0042] Figure 18 This is a flowchart of an embodiment of the assembly method of the secondary battery of the present invention.

[0043] Component designation explanation:

[0044] 100. Secondary battery; 110. Casing; 111. End wall; 112. Side wall; 113. Opening; 114. Groove; 120. Electrode assembly; 121. First electrode; 1211. Negative current collector; 1212. First electrode body; 1213. First empty foil area; 1214. First plane; 122. Separator; 123. Second electrode; 1231. Positive current collector; 1232. Second electrode body; 1233. Second empty foil area; 124. First current collector; 1241. Second plane; 125. Second current collector; 130. Current collector component; 131. Current collector body; 1311. Second straight line; 1312. 1313 Horizontal plane; 1314 Non-deformable area; 1315 Deformable area; 1316 Outermost end; 132 Pin; 1321 Suspended part; 1322 Connecting part; 13221 Arc body; 13222 Planar body; 1323 Shell welding part; 13231 Bottom end; 1324 Welding part; 1325 Bending guide part; 13251 Buffer hole; 13252 Weak part; 1326 First straight line; 1327 Bending structure; 13271 Bottom end of bending structure; 1328 Bending space; 140 Cover plate; 150 Terminal post; 160 Cell assembly part; 170 Area to be soldered. Detailed Implementation

[0045] 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, and 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. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should also be understood that the terminology used in the embodiments of the present invention is for describing specific implementation schemes and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0046] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of the invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to the methods, devices, and materials in the embodiments of the present invention.

[0047] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" used in this specification are only for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as part of the scope of the invention.

[0048] Please see Figures 1 to 18 This invention provides a current collector 130 for a secondary battery 100 and an assembly method for the secondary battery 100. The current collector 130 is used to connect the housing 110 and the electrode assembly 120 in the secondary battery 100. The current collector 130 includes a current collector body 131 and a plurality of pins 132 connected to the current collector body 131. The pins 132 include a housing welding portion 1323 and a connecting portion 1322 connecting the current collector body 131 and the housing welding portion 1323. The bottom end 13231 of the housing welding portion 1323 and the outermost end 1316 of the current collector body 131 have a height difference in the vertical direction. The connecting portion 1322 connects the outermost end 1316 and the bottom end 13231 along a straight line or an arc. The overall width of the connecting portion 1322 in the horizontal direction is L, the radius of the electrode assembly 120 is R, 5≤R / L≤20, and the overall height of the connecting portion 1322 in the vertical direction is H, 2≤L / H≤20. In this embodiment, by limiting the R / L and L / H ratios to the above-mentioned ranges, the connecting part 1322 can have a suitable degree of deformation, and at the same time, a deformation space matching the above-mentioned degree of deformation is formed. This improves the problem of excessive pressure deformation caused by excessive deformation of the connecting part 1322 itself or excessive deformation space requirement during the pressing of the groove 114, which would lead to the electrode assembly 120 being damaged and failed.

[0049] Alternatively, the connecting portion 1322 is bent toward one side of the current collector 131 to form an inner side close to the current collector 131 and an outer side away from the current collector 131, with a suspended portion 1321 formed on the outer side of the connecting portion 1322. When the current collector 131 is integrated into the housing 110 of the secondary battery 100, and when the current collector 131 is assembled to the electrode assembly 120, the suspended portion 1321 provides space for deformation of the housing welding portion 1323 when it bends toward the electrode assembly 120. This can alleviate the technical problem of excessive movement of the pin 132 toward the electrode assembly 120 during bending, which could damage the electrode assembly 120.

[0050] Please see Figure 1 and Figure 8The current collector 131 is used to connect to the electrode assembly 120. The shape of the current collector 131 can be any rotationally symmetrical shape, such as a circle, square, regular polygon, petal shape, or other shape with a center of symmetry that can coincide with the original shape after rotating around the center of symmetry by a certain angle. There is no limitation on this, as long as it can achieve a stable and reliable electrical connection with the electrode assembly 120. The center of the current collector 131 is its own center of symmetry. In this embodiment, the current collector 131 is approximately circular.

[0051] Please see Figure 1 and Figure 8 Multiple pins 132 are spaced apart and connected to the outer periphery of the current collector 131. This spaced arrangement reduces the processing difficulty of bending the pins 132 relative to the current collector 131 while ensuring the conductivity of the pins 132. The number of pins 132 is not limited; in this embodiment, four pins 132 are evenly distributed around the circumference of the current collector 131. The pins 132 and the current collector 131 can be integrally formed or fixedly connected separate components; this is not limited. In this embodiment, the pins 132 and the current collector 131 are integrally formed. Each pin 132 extends from the current collector 131 towards one side and bends, forming an angle between the pin 132 and the current collector 131. In this embodiment, the angle is greater than or equal to 90°, which facilitates subsequent fixed connection after assembly of the current collector component 130 and the housing 110. Preferably, the diameter of the current collector 131 is less than or equal to the diameter of the inner wall of the housing 110, and the diameter of the outer edge of the pin 132 is greater than or equal to the diameter of the inner wall of the housing 110. During the process of inserting the current collector 130 into the housing 110, the pin 132 tends to continue bending towards the center of the current collector 131, and the angle between the pin and the current collector 130 decreases, thereby achieving energy storage. The stored energy is used to achieve abutment and fixation between the pin 132 and the inner wall of the housing 110. This arrangement facilitates the positioning of the current collector 130, thereby improving the welding quality. The shape of the pin 132 is not limited, as long as it can form a stable fixed connection with the housing 110 to achieve conductivity. In this embodiment, the pin 132 is a fan-shaped ring structure.

[0052] Please continue reading. Figure 1 and Figure 8The pin 132 includes a connecting portion 1322 and a housing welding portion 1323. When the pin 132 and the current collector body 131 are integrally formed, the connecting portion 1322 is a bent structure formed at the connection between the pin 132 and the current collector body 131 when the pin 132 is bent. One end of the connecting portion 1322 is connected to the current collector member 130, and the other end is integrally connected to the housing welding portion 1323. The housing welding portion 1323 extends outward from the end of the connecting portion 1322 away from the current collector body 131. The housing welding portion 1323 is used to connect the housing 110.

[0053] Please see Figures 2 to 7 Considering that the pin 132 will bend due to the deformation of the groove 114 during the grooving process, and given the limited space between the groove 114 and the electrode assembly 120, the bent pin 132 is prone to move towards the electrode assembly 120, thereby damaging the electrode assembly 120. In this embodiment, the thickness direction of the current collector body 131 is defined as the vertical direction, such as... Figure 2 and Figure 5 As shown in the diagram (Y). The direction perpendicular to the vertical direction is defined as the horizontal direction, as shown in the diagram. Figure 2 and Figure 5 As shown in Figure X. In the vertical cross-section of the current collector 130 passing through pin 132, the current collector body 131 extends horizontally and includes an outermost end 1316. The housing weld portion 1323 extends vertically and includes a bottommost end 13231. The bottommost end 13231 of the housing weld portion 1323 and the outermost end 1316 of the current collector body 131 have a height difference in the vertical direction. The connecting portion 1322 connects the outermost end 1316 and the bottommost end 13231 along a straight line or an arc. The structural form of the connecting portion 1322 is not limited; it can be a single or continuous straight line segment, or an arc connection, as long as the overall vertical height H of the connecting portion 1322 is 3.55mm ≥ H ≥ 0.7mm, and the overall horizontal width L of the connecting portion 1322 is 5mm ≥ L ≥ 2.5mm. Please refer to [reference needed]. Figure 4 and Figure 7 .

[0054] It should be noted that the overall height H of the connecting portion 1322 in the vertical direction refers to the sum of the heights of the multiple straight lines in the vertical direction when the connecting portion 1322 includes multiple straight lines. Similarly, the overall width of the connecting portion 1322 in the horizontal direction refers to the sum of the widths of the multiple straight lines in the horizontal direction when the connecting portion 1322 includes multiple straight lines. This configuration allows for a shorter path to connect the outermost end 1316 and the bottommost end 13231. Furthermore, during the pressing process of the groove 114, it mitigates the problem of excessive pressing deformation caused by excessive deformation of the connecting portion 1322 itself or excessive deformation space requirements, which could lead to pressure on the electrode assembly 120 and cause damage or failure of the electrode assembly 120.

[0055] This can also be understood as a suspended portion 1321 being formed on the outer side of the connecting portion 1322. For details, please refer to... Figures 3 to 4 and Figures 6 to 7 A first straight line 1326, running vertically through the outermost side of the housing weld portion 1323, intersects a second straight line 1311, running horizontally through the current collector body 131 near the bottom of the electrode assembly 120. A suspended portion 1321 is located on the outer surface of the first straight line 1326, the second straight line 1311, and the connecting portion 1322. The suspended portion 1321 provides space for deformation when the housing weld portion 1323 bends towards the electrode assembly 120, mitigating the technical problem of excessive movement of the pin 132 towards the electrode assembly 120 during bending, which could damage the electrode assembly 120.

[0056] Please see Figures 2 to 7 First, the suspended portion 1321 provides more space for the deformation of the pin 132 towards the electrode assembly 120, which can alleviate the technical problem of excessive movement of the pin 132 towards the electrode assembly 120 after bending and deformation, thus preventing damage to the electrode assembly 120. Second, the outermost end 1316 and the bottommost end 13231 are connected by a shorter path, which shortens the total length of the connecting portion 1322, reduces the material cost of the connecting portion 1322, and the reduction in material will further reduce the space required after the pin 132 is bent. This allows the bent pin 132 to be accommodated in the limited space between the groove 114 and the electrode assembly 120, thereby alleviating the damage to the electrode assembly 120 caused by the bending of the pin 132. Furthermore, during the bending process of pin 132, the suspended portion 1321 provides space to accommodate the downward movement of pin 132. During this downward movement, the space subjected to pressure from the current collector decreases, which can alleviate the pressure on the connection portion 1322, thereby reducing the tearing of the weld portion 1324 formed between the housing weld portion 1323 and the sidewall 112. This reduces the risk of breakage and failure of the weld between pin 132 and housing 110 at the weld portion 1324, thereby improving product yield.

[0057] Please see Figure 2 , Figure 3 and Figure 9In one embodiment of the current collector component 130 of the present invention, the connecting portion 1322 includes an arc-shaped body 13221 connecting the outer periphery of the housing welding portion 1323 and the current collector body 131. The arc-shaped body 13221 is arc-shaped in vertical cross-section. The connecting portion 1322 can be entirely an arc-shaped body 13221 or partially an arc-shaped body 13221, and there is no limitation thereto. In this embodiment, the connecting portion 1322 is entirely an arc-shaped body 13221. The setting of the arc-shaped body 13221 can shorten the length of the connecting portion 1322, reduce the space required after the pin 132 is bent, and thus alleviate the damage to the electrode assembly 120 caused by the bending of the pin 132. In addition, the arc-shaped body 13221 also facilitates the bending of the connecting portion 1322 with the groove 114. Therefore, during the bending process of the pin 132, the tearing of the housing welding portion 1323 on the welding portion 1324 can be alleviated. This reduces the risk of breakage and failure when pin 132 and housing 110 are soldered at solder joint 1324.

[0058] Please see Figure 3 In one embodiment of the current collector 130 of the present invention, the radius of the outer wall of the arc 13221 is R, where 3.55mm ≥ R ≥ 0.7mm. The radius R ≥ 0.7mm of the arc 13221 provides sufficient space to accommodate the deformation of the connecting portion 1322, thus mitigating the technical problem of excessive movement of the pin 132 towards the electrode assembly 120 after bending, which could damage the electrode assembly 120. The radius R ≤ 3.55mm of the arc 13221 ensures that it can be accommodated inside the housing 110 and meets the bending requirements of the groove 114.

[0059] Please see Figure 5 , Figure 6 and Figure 10In one embodiment of the current collector 130 of the present invention, the connecting portion 1322 includes a single planar body 13222 or multiple planar bodies 13222 connected end to end. The planar body 13222 is straight in vertical cross-section. The plane passing through the bottom side of the current collector body 131 and perpendicular to the vertical direction is defined as the horizontal plane 1312. It should be noted that the bottom side of the current collector body 131 is the position closest to the electrode assembly 120. There is an angle between the planar body 13222 and the horizontal plane 1312, and the size of the angle is not limited. The connecting portion 1322 can be entirely the planar body 13222, or it can be partially a planar body 13222. The planar body 13222 can be a single segment or multiple connected segments. The multiple planar body segments 13222 can be directly or indirectly connected, and there is no limitation on this, as long as the connecting portion 1322, the first straight line 1326, and the second straight line 1311 can form a suspended portion 1321 that can accommodate the deformation of the pin 132. Preferably, the connection between the planar body 13222 and the current collector body 131 and the housing welded part 1323 is smooth. If the planar body 13222 has multiple segments, the connection between the multiple segments of the planar body 13222 is also smooth, so as to reduce the bending stress at each connection.

[0060] In this embodiment, please refer to Figure 6 and Figure 7 The connecting portion 1322 is entirely a planar body 13222, which is angled to the current collector body 131, similar to the hypotenuse of a triangle. Firstly, the planar body 13222 shortens the length of the connecting portion 1322, reducing the space required after bending the pin 132, thus mitigating damage to the electrode assembly 120 caused by bending the pin 132. Secondly, a suspended portion 1321 is formed on the outer side of the planar body 13222, providing space for deformation during bending of the pin 132, thus mitigating the technical problem of damage to the electrode assembly 120 caused by excessive movement of the pin 132 towards the electrode assembly 120 after bending. Thirdly, the final cross-sectional shape of the pin 132 after bending with the groove 114 is similar to a triangle, such as... Figure 17 As shown, when the secondary battery 100 is depressurized, the middle part of the current collector 131 begins to fold away from the electrode assembly 120. This triangular structure provides a fulcrum for the folded part, allowing the current collector 131 to fold over a larger area to obtain a larger depressurization area and improve the safety performance of the secondary battery 100.

[0061] Please see Figure 6In one embodiment of the current collector 130 of the present invention, the overall height of the planar body 13222 in the vertical direction is 'a', where 3.55mm ≥ a ≥ 0.7mm. It should be noted that the overall height 'a' of the planar body 13222 in the vertical direction refers to the sum of the heights of the multiple planar body segments 13222 connected end-to-end when the connecting portion 1322 includes such segments. Setting a ≥ 0.7mm provides sufficient space to accommodate the deformation of the connecting portion 1322, thus mitigating the technical problem of excessive movement of the pin 132 towards the electrode assembly 120 after bending, which could damage the electrode assembly 120. Setting a ≤ 3.55mm ensures that the connecting portion 1322 can be accommodated inside the housing 110 and meets the bending requirements of the groove 114.

[0062] Please see Figures 1 to 10 In one embodiment of the current collector 130 of the present invention, the pin 132 includes a bending guide 1325 disposed on the connecting portion 1322. The form of the bending guide 1325 is not limited; for example, it can be softened by using openings, thinning, or material modification, as long as it achieves the effect of bending the connecting portion 1322 at the bending guide 1325, thus achieving a more controllable deformation effect. This can alleviate the damage to the electrode assembly 120 caused by the bending of the pin 132, and also alleviate the tearing of the weld portion 1324 formed between the housing weld portion 1323 and the sidewall 112, reducing the risk of breakage and failure of the pin 132 and the housing 110 at the weld portion 1324.

[0063] Considering that during mechanical sealing, the bending process of pin 132 will exert a large tensile force on the weld 1324 formed between pin 132 and housing 110, which may lead to the risk of pin 132 breaking at the weld 1324, please refer to [link to relevant documentation]. Figures 8 to 10 In this embodiment, each bending guide portion 1325 includes at least one buffer hole 13251. The buffer hole 13251 penetrates along the thickness direction of the connecting portion 1322 and extends circumferentially along the collecting member 130. The number of buffer holes 13251 is not limited and can be one, two, three, or more. The shape of the buffer hole 13251 is not limited and can be, for example, circular, elliptical, oblong, rectangular, or other irregular closed shapes. In this embodiment, the buffer hole 13251 is an oblong hole.

[0064] Please see Figures 8 to 10In one embodiment of the current collection component 130 of the present invention, the wall profile of the buffer hole 13251 is a continuous and smooth closed profile. The shape of the buffer hole 13251 is not limited, and can be, for example, a circular hole, an oblong hole, an elliptical hole, or other irregular continuous and smooth closed profiles. Setting the wall profile of the buffer hole 13251 to a continuous and smooth closed profile can improve the problem of sharp edges or corners on the hole wall, which can lead to stress concentration, and reduce the risk of the buffer hole 13251 being easily torn at the stress concentration location.

[0065] Please see Figures 8 to 10 During the mechanical sealing process, as the pin 132 continues to bend towards the axis of the current collector 131: on the one hand, the buffer hole 13251 reduces the difficulty of bending through a local thinning effect. On the other hand, the buffer hole 13251 can absorb stress through plastic deformation. Furthermore, the stress isolation zone formed at the edge of the buffer hole 13251 blocks the stress transmission path. This weakens the transmission of stress from the pin 132 during bending to the connection between the pin 132 and the housing 110, thereby reducing the risk of breakage of the current collector 130 at the connection with the housing 110 and improving the technical problem of easy fixation failure between the current collector 130 and the housing 110.

[0066] Considering that when the connection between pin 132 and housing 110 is soldered, due to diffuse reflection of the laser on pin 132, the reflected laser may pass through buffer hole 13251 and burn electrode assembly 120. Please refer to... Figures 9 to 10 In one embodiment of the current collector 130 of the present invention, the buffer hole 13251 is located at the portion of the housing weld 1323 or the connecting portion 1322 near the housing weld 1323. This arrangement ensures that the buffer hole 13251 and the electrode assembly 120 do not overlap, reducing the risk of reflected laser light irradiating the electrode assembly 120 through the buffer hole 13251, thereby reducing the risk of the electrode assembly 120 being burned.

[0067] Please see Figure 16 and Figure 17 Considering that the bending process of pin 132 will exert a large tensile force on the solder joint 1324, which may cause the pin 132 to break at the solder joint 1324, during the subsequent sealing process, the current collector 130 is subjected to downward pressure. After the current collector 130 breaks, its edge is close to vertical, and under pressure, there is a possibility that the electrode assembly 120 may be inserted. In one embodiment of the current collector 130 of the present invention, please refer to... Figure 3 and Figure 6The connecting portion 1322 includes a weak portion 13252 for reducing stress during bending. The weak portion 13252 is made by reducing the material thickness. The shape and size of the weak portion 13252 are not limited; for example, it can be one or more combinations of thinning, scoring, and hollowing, as well as any other form that can reduce stress during bending. All of the above forms can reduce the strength of the weak portion 13252 by reducing its cross-sectional area. By providing the weak portion 13252 on the connecting portion 1322, the stress during bending can be reduced, making the connecting portion 1322 itself easier to bend and less prone to breakage. Furthermore, since the junction between the weak point 13252 and the current collector body 131 deforms first during bending, the stress transmission to the welded connection between the current collector 130 and the electrode assembly 120 can be reduced. This reduces the risk of the current collector 130 breaking at the weld 1324 and improves the problem of weld failure between the current collector 130 and the current collector caused by bending stress. Additionally, it reduces the risk of the edge of the current collector 130 being pressed into the electrode assembly 120 during the upsetting process, thereby improving product yield.

[0068] The weak portion 13252 can take various forms. In one embodiment, the weak portion 13252 is thinned. Please refer to [link / reference]. Figure 3 and Figure 6 In another embodiment, the weak portion 13252 is a hollow structure. It is understood that the shape of the hollow structure is not limited to a circular hole as shown in the figure; it can also be elliptical, rhomboid, or any other shape that can reduce stress when the connecting portion 1322 is bent. In some other embodiments, the weak portion 13252 can also be a groove or a combination of the above forms. The weak portion 13252 can be continuous or discontinuous; there is no limitation on this.

[0069] Please see Figures 11 to 18 The present invention also provides a method for assembling a secondary battery 100, the secondary battery 100 including a housing 110, an electrode assembly 120 and a cover plate 140, the housing 110 including a surrounding side wall 112, one end of the side wall 112 having an opening 113, the assembly method including the following steps:

[0070] S1. A current collection component 130 is provided in one embodiment of the present invention.

[0071] The current collector 130 includes a current collector body 131 and a plurality of pins 132 connected to the current collector body 131. The structural forms of the current collector body 131 and the pins 132 are as described in the above embodiments and will not be elaborated here.

[0072] S2. The current collector body 131 of the current collector component 130 is welded to the current collector part of the electrode assembly 120 to form the cell assembly part 160.

[0073] Please see Figure 11 In this embodiment, the first current collector 124 is welded to the current collector body 131. The specific location and area of ​​the welding connection between the current collector body 131 and the first current collector 124 are not limited, as long as the current guiding requirements between the current collector component 130 and the first current collector 124 are met. The specific execution process of this step can refer to the welding process between the current collector component 130 and the electrode assembly 120 in the known art, and will not be described in detail here.

[0074] S3. Install the cell assembly part 160 into the housing 110 through the opening 113, and make the current collector 130 face the opening 113.

[0075] Please see Figure 11 Provided that the cell assembly part 160 can be installed into the housing 110 through the opening 113, the specific installation method of the cell assembly part 160 is not limited. For example, it can be installed manually or by a robotic arm.

[0076] S4. The pins 132 of the current collector 130 are attached to the side wall 112 of the housing 110, forming a solderable area 170 between the current collector 130 and the side wall 112.

[0077] Please see Figure 11 and Figure 12 The pin 132 includes a housing welding portion 1323 and a connecting portion 1322 connecting the outer periphery of the housing welding portion 1323 and the current collector body 131. The housing welding portion 1323 overlaps with the side wall 112 of the housing 110 to form a soldering area 170 between the pin 132 and the side wall 112. The specific location of the soldering area 170 is not limited; any area that meets the soldering spacing requirements between the pin 132 and the side wall 112 can be used as the soldering area 170.

[0078] S5. Solder the area to be soldered 170 to form a solder joint 1324 between the pin 132 and the sidewall 112.

[0079] Please see Figures 11 to 13 When welding the area 170 to be welded, welding can be performed on the inside of the housing 110 or on the outside of the housing 110, as long as a weld portion 1324 that meets the strength requirements is formed between the connecting piece and the side wall 112.

[0080] S6. Roll the side wall area corresponding to the welded part 1324 to form a groove 114, and make the groove 114 restrict the axial displacement of the current collector body 131 and the electrode assembly 120.

[0081] Please see Figure 14 and Figures 16 to 17 The forming method of the groove 114 is not limited. For example, it can be formed by grooving the side wall 112 with a grooving tool, or it can be formed by stamping the side wall 112 with a forming mold. The cross-sectional shape of the groove 114 can be any shape that meets the requirements of use, such as rectangular, square or trapezoidal. There are no specific restrictions on this in the present invention.

[0082] S7. The cover plate 140 is sealed and installed at the opening 113 on the side of the groove 114 opposite to the electrode assembly 120.

[0083] Please see Figure 14 The outer periphery of the cover plate 140 overlaps the surface of the groove 114 facing the opening 113 by a sealing ring. Then, the opening 113 area of ​​the side wall 112 is sealed, thereby sealing the cover plate 140 at the opening 113 position of the housing 110.

[0084] Considering that pin 132 will bend during the grooving process due to the deformation of grooving 114, and given the limited space between grooving 114 and electrode assembly 120, the bent pin 132 is prone to moving towards electrode assembly 120, potentially damaging it. To address this issue, please refer to [link to relevant documentation]. Figures 2 to 7 In this embodiment, the thickness direction of the current collector body 131 is defined as the vertical direction, and the direction perpendicular to the vertical direction is defined as the horizontal direction. On the vertical cross-section of the current collector component 130 passing through the pin 132, the current collector body 131 extends horizontally and includes an outermost end 1316. The housing weld portion 1323 extends vertically and includes a bottommost end 13231. The bottommost end 13231 of the housing weld portion 1323 and the outermost end 1316 of the current collector body 131 have a height difference in the vertical direction. The connecting portion 1322 connects the outermost end 1316 and the bottommost end 13231 along a straight line or an arc. The overall width of the connecting portion 1322 in the horizontal direction is L, the radius of the electrode assembly 120 is R, 5 ≤ R / L ≤ 20, and the overall height of the connecting portion 1322 in the vertical direction is H, 2 ≤ L / H ≤ 20. Please refer to [link to relevant documentation]. Figure 4 , Figure 7 and Figure 12 This arrangement allows the connector 1322 to have a suitable degree of deformability, while a suspended portion 1321 is formed on the outer side of the connector 1322. The outermost end 1316 and the bottommost end 13231 are connected by a shorter path, which shortens the total length of the connector 1322, reduces the material cost of the connector 1322, and the reduction in material will further reduce the space required after the pin 132 is bent, thus realizing the inclusion of the bent pin 132 in the limited space between the groove 114 and the electrode assembly 120.

[0085] Please see Figure 14 and Figure 15 In one embodiment of the current collector 130 of the present invention, the electrode assembly 120 of the secondary battery 100 is housed within the casing 110. The electrode assembly 120 is a component in the secondary battery 100 where an electrochemical reaction occurs. The casing 110 may contain one or more electrode assemblies 120. The electrode assembly 120 includes an electrode structure formed by stacking or 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. Both the first electrode 121 and the second electrode 123 include an electrode body coated with an active material of the corresponding polarity and a current collecting portion extending out of the electrode body. For distinction, the electrode body of the first electrode 121 is defined as the first electrode body 1212, the electrode body of the second electrode 123 is defined as the second electrode body 1232, the current collecting portion of the first electrode 121 is defined as the first current collecting portion 124, and the current collecting portion of the second electrode 123 is defined as the second current collecting portion 125.

[0086] Please see Figures 14 to 15 In 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 first electrode 121 includes a first electrode body 1212 coated with active material and a first empty foil area 1213 uncoated with active material. The first empty foil area 1213 is located at the end of the first electrode 121. The first empty foil area 1213 extends out of the diaphragm 122 along the winding axis direction of the electrode assembly 120 and bends towards the winding axis to form a first current collector 124. The first current collector 124 is the corresponding negative current collector.

[0087] Please see Figures 14 to 15 The second electrode 123 is a positive electrode. Specifically, the second electrode 123 includes a positive current collector 1231 and a positive active material. The positive active material is coated on the surface of the positive current collector 1231. The positive current collector 1231 includes a second electrode body 1232 coated with active material and a second empty foil area 1233 uncoated with active material. The second empty foil area 1233 is located at the end of the second electrode 123. The other end of the second empty foil 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 current collector 125. The second current collector 125 is the corresponding positive current collector.

[0088] Please see Figures 14 to 15A separator 122 is disposed between the first electrode 121 and the second electrode 123 to isolate the positive electrode active material layer and the negative electrode active material layer. Taking a lithium-ion secondary battery 100 as an example, the positive electrode current collector 1231 can be made of aluminum, and the positive electrode active material layer includes positive electrode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode current collector 1211 can be made of copper, and the negative electrode active material layer includes negative electrode 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.

[0089] Please see Figure 14 and Figure 15 Furthermore, if the first current collector 124 faces the end wall 111 or the opening 113, then the second current collector 125 faces the other end of the housing 110. In this embodiment, the second current collector 125 faces the end wall 111 and is electrically connected to the electrode 150, making the electrode 150 positively charged. The first current collector 124 faces the opening 113, and the housing 110 is electrically connected to the first current collector 124, thus becoming negatively charged. However, in another embodiment, the first current collector 124 can be connected to the electrode 150, and the second current collector 125 can be connected to the housing 110.

[0090] Please see Figure 13 The plane containing the end face of the first electrode body 1212 is defined as the first plane 1214, and the plane containing the end face of the bent first current collector 124 is defined as the second plane 1241; the distance between the first plane 1214 and the second plane 1241 is d, as follows: Figure 13 As shown. Before the pin 132 is bent, the current collector body 131 is flush with the second plane 1241, and the connection part 1322 is located on the side of the current collector body 131 away from the electrode assembly 120, as shown. Figures 11 to 13 As shown. During the bending process of pin 132, the connecting part 1322 will bend to form a bent structure 1327. Part of the bent structure 1327 will be pressed between the first plane 1214 and the second plane 1241. The bottom end of the bent structure 1327 facing the electrode assembly 120 is defined as the bottom end of the bent structure 13271. The maximum distance between the bottom end 13271 of the bent structure and the first plane 1214 is defined as L1. Figure 16 and Figure 17As shown. In order to prevent damage to the electrode assembly 120 in the part pressed between the first plane 1214 and the second plane 1241 in the bending structure 1327, L1 ≤ d must be limited.

[0091] Please see Figure 16 and Figure 17 To achieve the above-mentioned technical objectives, the present invention employs a current collector 130 with a suspended portion 1321 formed on the outer side of the connecting portion 1322. The suspended portion 1321 provides sufficient space for deformation of the pin 132 during the rolling of the groove 114. The suspended portion 1321 shortens the total length of the connecting portion 1322 and reduces the space required after the pin 132 is bent. Therefore, the connecting portion 1322 is bent to form a bent structure 1327. In one embodiment of the secondary battery 100 assembly method of the present invention, in the step of rolling the side wall area corresponding to the welding portion 1324 to form the groove 114 and restricting the axial displacement of the electrode assembly 120 by the groove 114: the connecting portion 1322 of the current collector 130 is bent to form a bent structure 1327. The form of the bent structure 1327 may be various and is not limited thereto. For example, in one embodiment, the current collector 130 is bent to form Figure 16 The bent structure 1327 is shown. In some other embodiments, the current collector 130 forms a bent structure. Figure 17 The bending structure 1327 is shown. To ensure L1≤d, further, in this embodiment, the maximum distance between the bottom end 13271 of the bending structure 1327 facing the electrode assembly 120 and the first plane 1214 is L1, such that 0≤L1≤2.5mm. The range defined by 0≤L1≤2.5mm corresponds to the maximum distance from the bottom end 13271 of the bending structure to or from the first plane 1214 being less than or equal to 2.5mm. Figure 17 As shown. Although the bending structure 1327 has a tendency to move toward the electrode assembly 120, it will not damage the electrode assembly 120, thereby improving product yield.

[0092] The suspended portion 1321 provides ample space for the deformation of the pin 132 during the rolling and grooving process 114. The suspended portion 1321 shortens the overall length of the connecting portion 1322 and reduces the space required after the pin 132 is bent. Therefore, the connecting portion 1322 is bent to form a bent structure 1327. The bent structure 1327 may take various forms, and this is not limited. For example, in one embodiment, the current collector 130 is bent to form... Figure 16 The bent structure 1327 is shown. In some other embodiments, the current collector 130 forms a bent structure. Figure 17The bending structure 1327 is shown. To ensure L1≤d, in this embodiment, 0≤L1≤2.5mm is further defined. The range defined by 0≤L1≤2.5mm corresponds to the maximum distance from the bottom end 13271 of the bending structure to or from the first plane 1214 being less than or equal to 2.5mm. Figure 17 As shown. Although the bending structure 1327 has a tendency to move toward the electrode assembly 120, it will not damage the electrode assembly 120, thereby improving product yield.

[0093] Please see Figure 17 In one embodiment of the secondary battery 100 assembly method of the present invention, the current collector body 131 includes a non-deformable region 1313 and a deformable region 1314. The non-deformable region 1313 is the region that does not deform before and after the groove 114, and the deformable region 1314 is the region that deforms before and after the groove 114. The deformable region 1314 is typically located in the region where the outer periphery of the current collector body 131 connects to the connecting portion 1322, and is connected to the connecting portion 1322. The maximum offset distance of the deformable region 1314 relative to the non-deformable region 1313 is L2, where 0≤L2≤2.5mm. This limitation can ensure that the maximum offset position of the deformable region 1314 does not enter the first electrode body 1212, causing damage to the electrode assembly 120, thereby improving the product yield.

[0094] Please see Figure 16 and Figure 17 In one example of the secondary battery 100 of the present invention, a bending space 1328 is formed between the housing welded portion 1323 and the side of the current collector 131 facing away from the electrode assembly 120. The bending space 1328 has the characteristic of flexible deformation, which allows the current collector 131 to maintain an adaptive fit with the electrode assembly 120 through flexible deformation, reducing contact resistance fluctuations. It can also absorb the cumulative assembly errors of the current collector 130 and the housing 110 generated during the assembly process through geometric degree of freedom compensation.

[0095] Please see Figure 17 In one example of the secondary battery 100 of the present invention, the bending space 1328 is triangular. When the secondary battery 100 is depressurized, the middle part of the current collector body 131 begins to fold away from the electrode assembly 120. This triangular structure can provide a fulcrum for the folded part, so that the current collector body 131 can fold to a larger extent to obtain a larger pressure relief area and improve the safety performance of the secondary battery 100.

[0096] This invention relates to a current collector component, comprising a current collector body and a plurality of pins spaced apart and connected to the current collector body. Each pin includes a connecting portion for connection to the current collector body and a housing weld portion for connection to a housing. The bottom end of the housing weld portion and the outermost end of the current collector body have a vertical height difference, and the connecting portion connects the outermost and bottom ends along a straight line or arc. The overall width of the connecting portion in the horizontal direction is L, the radius of the electrode assembly is R, where 5 ≤ R / L ≤ 20, and the overall height of the connecting portion in the vertical direction is H, where 2 ≤ L / H ≤ 20. By limiting the ratios R / L and L / H to the aforementioned ranges, the connecting portion can have a suitable degree of deformation, while simultaneously forming a deformation space matching the aforementioned degree of deformation. This mitigates the problem of excessive downward deformation caused by excessive deformation of the connecting portion itself or excessive deformation space requirements during the rolling groove pressing process, which could lead to excessive pressure on the electrode assembly and subsequent damage or failure of the electrode assembly.

[0097] Therefore, this invention effectively overcomes some practical problems in the prior art, thus possessing high utilization value and significance. The above embodiments are merely illustrative of the principles and effects of this 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 this invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this invention.

Claims

1. A current collector for a secondary battery, characterized in that, include: Current collector body, used to connect electrode assembly; Multiple pins are spaced apart on the outer periphery of the current collector body. Each pin includes a housing welding part and a connecting part that connects the housing welding part and the outer periphery of the current collector body. The housing welding part is used to connect the housing. Wherein, the thickness direction of the current collector body is defined as the vertical direction, and the direction perpendicular to the vertical direction is defined as the horizontal direction. On the vertical cross-section of the current collector component passing through the pin along the vertical direction, the current collector body extends along the horizontal direction and includes an outermost end, the housing welded part extends along the vertical direction and includes a bottommost end, the bottommost end of the housing welded part and the outermost end of the current collector body have a height difference along the vertical direction, the connecting part connects the outermost end and the bottommost end along a straight line or an arc, the overall width of the connecting part along the horizontal direction is L, the radius of the electrode assembly is R, where 5≤R / L≤20, and the overall height of the connecting part along the vertical direction is H, where 2≤L / H≤20.

2. The current collection component according to claim 1, characterized in that, The overall width L of the connecting part along the horizontal direction is in the range of 5mm ≥ L ≥ 2.5mm, and the overall height H of the connecting part along the vertical direction is in the range of 3.55mm ≥ H ≥ 0.7mm.

3. The current collection component according to claim 1, characterized in that, The connecting part includes an arc-shaped part that connects the outer periphery of the housing welded part and the current collecting body, and the arc-shaped part is arc-shaped in the vertical cross section.

4. The current collection component according to claim 3, characterized in that, The radius of the outer wall of the arc is R, where 3.55mm ≥ R ≥ 0.7mm.

5. The current collection component according to claim 1, characterized in that, The connecting part includes a single-section planar body or multiple sections of planar bodies connected end to end. The planar body is straight in the vertical cross-section. The plane passing through the bottom side of the flow collecting body and perpendicular to the vertical direction is defined as a horizontal plane. The planar body and the horizontal plane have an angle between them.

6. The current collection component according to claim 5, characterized in that, The overall height of the planar body along the vertical direction is a, where 3.55mm ≥ a ≥ 0.7mm.

7. The current collection component according to claim 1, characterized in that, The pin includes a bent guide portion disposed at the connector.

8. The current collection component according to claim 7, characterized in that, The bending guide includes a buffer hole that extends through the thickness of the connecting part and extends circumferentially along the current collecting member.

9. The current collection component according to claim 7, characterized in that, The bending guide includes a weak portion disposed in the connecting portion, and the weak portion is subjected to material thickness reduction treatment.

10. A method for assembling a secondary battery, the secondary battery comprising a casing, an electrode assembly, and a cover plate, the casing comprising a surrounding sidewall, one end of the sidewall having an opening, characterized in that, The assembly method includes the following steps: Provide a current collection component as described in claim 1; The current collector body of the current collector component is welded to the current collector part of the electrode assembly to form a cell assembly part; The cell assembly is installed into the housing through the opening, with the current collector facing the opening; The pins of the current collector are made to overlap with the side wall of the housing, forming a solderable area between them; The area to be soldered is soldered to form a weld between the pin and the sidewall; Rolling is performed on the side wall region corresponding to the welded portion to form a groove, and the groove restricts the axial displacement of the current collector and the electrode assembly; The cover plate is sealed and installed on the side of the groove opposite to the electrode assembly to block the opening.

11. The assembly method of the secondary battery according to claim 10, characterized in that, In the step of rolling the side wall area corresponding to the welded part to form a groove and restricting the axial displacement of the electrode assembly by the groove: the connecting part of the current collector is bent to form a curved structure, and the maximum distance between the bottom end of the curved structure facing the electrode assembly and the first plane is greater than or equal to 0 and less than or equal to 2.5 mm, wherein the electrode assembly includes an electrode body and a current collector layered on the end face of the electrode body facing the opening, and the first plane is the plane where the end face of the electrode body is located.

Images