Cell welding structure, welding method, and battery

Abstract

The present application relates to the technical field of batteries, and provides a cell welding structure, a welding method, and a battery. The cell welding structure comprises: a winding body; a plurality of tab groups formed at an end portion of the winding body, the plurality of tab groups being radially arranged around the center of the winding body; and a current collector, welded to the side of the plurality of tab groups facing away from the winding body to form a plurality of welding spots. The present application can improve the uniformity of current conduction between die-cut tabs and electrode sheets, reduce the amount of current loss, reduce the number of welding spots, and improve work efficiency.

Description

Battery cell welding structure, welding method and battery

[0001] This application claims priority to the Chinese patent application No. 202410765582.6, filed on June 13, 2024, to the Chinese Patent Office, the whole content of the above application being incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of battery, in particular to a battery cell welding structure, a welding method and a battery. BACKGROUND

[0003] In a cylindrical battery, the tab and the current collector plate are welded to form a plurality of welding points, and the current received by the current collector plate is introduced into the tab through these welding points. The welding of the tab and the current collector plate usually adopts the full-tab laser welding method, which is simple to process. SUMMARY

[0004] The flow path of the current after the welding of the tab is irregular, which results in that some areas of the tab receive more current and some areas receive less current, thereby increasing the loss of the current and affecting the overcurrent performance of the tab.

[0005] In a first aspect, the present application provides a battery cell welding structure, comprising:

[0006] a winding body;

[0007] a plurality of tab groups formed at the end of the winding body, the plurality of tab groups being arranged radially around the center of the winding body;

[0008] a current collector piece welded with the side of the plurality of tab groups away from the winding body to form a plurality of welding points.

[0009] In a second aspect, the embodiments of the present application provide a battery cell welding method for manufacturing the battery cell welding structure of the first aspect, comprising:

[0010] obtaining winding parameters, welding parameters and die-cutting parameters, the winding parameters including the inner diameter, the outer diameter and the number of turns of the winding, the welding parameters including the arc distance between adjacent welding points in each turn of the winding along the direction of the winding, and the die-cutting parameters including the included angle between the adjacent two tab groups along the circumferential direction of the winding body;

[0011] simulating the winding shape and the welding trajectory of the battery cell welding structure according to the winding parameters, the welding parameters and the die-cutting parameters;

[0012] winding the tab connected with the tab group to form the winding body according to the winding shape;

[0013] According to the welding track, the welding positions between the tab groups and the current collector are determined and welded to form a plurality of welding points.

[0014] In a third aspect, the embodiments of the present application provide a battery comprising the cell welding structure according to the first aspect or the cell welding structure prepared by the cell welding method according to the second aspect. Advantages

[0015] In the embodiments of the present application, by arranging the plurality of tab groups radially around the winding body and forming a plurality of welding points on the tab groups, the plurality of welding points are limited on the radially arranged tab groups, which is beneficial to improve the disorder of the distribution of the plurality of welding points and improve the regularity of the distribution of the welding points, thereby reducing the current loss. In detail, the plurality of tab groups are arranged radially around the center of the winding body to improve the regularity of the distribution of the tab groups, and the tab groups are welded with the current collector to form a plurality of welding points, so that the plurality of welding points also have a certain regularity, effectively improving the problem that the welding points are too disorderly in the full-tab welding, leading to the disorder of the current flow and increasing the current loss. The tab groups are welded with the current collector to form a plurality of welding points, so that the welding points are limited on the tab groups with regular distribution, improving the disorderly distribution of the plurality of welding points, and then when the current is introduced into the pole piece through the welding points, the current introduction is more uniform, the conduction path of the current in the winding body is reduced, thereby improving the overcurrent capacity of the winding body and reducing the current loss. BRIEF DESCRIPTION OF DRAWINGS

[0016] FIG. 1 is a structural schematic diagram of a cell welding structure provided by the present application (omitting the winding circle traces of the pole piece between the initial winding and the final winding);

[0017] FIG. 2 is a schematic diagram of the shape of a winding body before being flattened and before being marked with welding points provided by the present application;

[0018] FIG. 3 is a schematic diagram of the shape of a winding body without eliminating the welding point marks provided by the present application (omitting the die-cut tab and full tab);

[0019] FIG. 4 is a schematic diagram of the shape of a winding body after being flattened and die-cutting the tab and full tab but without marking the welding points provided by the present application (omitting the winding circle traces of the pole piece between the initial winding and the final winding);

[0020] FIG. 5 is a schematic diagram of unfolding the shape of the winding body in FIG. 4 provided by the present application;

[0021] FIG. 6 is a flow schematic diagram of a cell welding method provided by the present application.

[0022] Explanation of reference signs:

[0023] 100 - winding body; 110 - pole piece; 200 - tab group; 210 - die-cut tab; 300 - solder point group; 310 - solder point; 400 - full tab; Q - winding direction; R - radial direction. Embodiments of the present application

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person skilled in the art without creative work fall within the scope of protection of the present application.

[0025] In the present application, the word "exemplary" is used to mean "serving as an example, instance, or illustration." The following description is presented to enable any person skilled in the art to make and use the present application. In the following description, for purposes of explanation, specific details are set forth.

[0026] Please refer to FIG. 1, the embodiments of the present application provide an electric core welding structure, comprising:

[0027] a winding body 100;

[0028] a plurality of tab groups 200 formed at the end of the winding body 100, the plurality of tab groups 200 are arranged radially around the center of the winding body 100;

[0029] a current collector welded with the side of the plurality of tab groups 200 away from the winding body 100 to form a plurality of solder points 310.

[0030] The technical solutions provided by the present application mainly arrange the plurality of tab groups 200 radially around the winding body 100, and form a plurality of solder points 310 on the tab groups 200, so that the plurality of solder points 310 are limited on the radial plurality of tab groups 200, which is beneficial to improve the disorder degree of the distribution of the plurality of solder points 310 and improve the regularity of the distribution of the solder points 310, thereby reducing the current loss. In detail, the plurality of tab groups 200 are arranged radially around the center of the winding body 100 to improve the regularity of the distribution of the tab groups 200, and the tab groups 200 are welded with the current collector to form a plurality of solder points 310, so that the plurality of solder points 310 also have a certain regularity, effectively improving the problem that the solder points are too disorderly in full tab welding, leading to chaotic current flow and increasing current loss. The tab groups 200 are welded with the current collector to form a plurality of solder points, so that the solder points 310 are limited on the tab groups 200 with regular distribution, improving the disorderly distribution of the plurality of solder points 310, and then when the current is introduced into the pole piece 110 through the solder points, the current introduction is more uniform, the conduction path of the current in the winding body 100 is reduced, thereby improving the overcurrent capacity of the winding body 100 and reducing the current loss.

[0031] Further, the plurality of tab groups 200 are arranged along the circumferential direction of the winding body 100, and the tab groups 200 extend along the radial direction R of the winding body 100. Among them, along the circumferential direction, the extension lines of the radial directions R of the two adjacent tab groups 200 intersect to form a first included angle, the range of the first included angle is 30° to 90°, the angle error range between the plurality of first included angles is 0° to 5°, and the tab groups 200 are welded with the current collector to form a plurality of welding points 310. By arranging a plurality of tab groups 200 along the circumferential direction of the winding body 100, and the angle error range between the plurality of tab groups 200 is 0° to 5°, the plurality of tab groups 200 tend to be arranged at equal angles along the circumferential direction, that is, tend to be arranged at equal arc distances, and the tab groups 200 are welded with the current collector to make the plurality of welding points 310 on the tab groups 200, limit the distribution position of the plurality of welding points 310, effectively improve the problem that the current may cause the path to be longer when flowing from the welding points 310, affect the current loss and overcurrent performance, and improve the regularity of the distribution of the welding points 310 and reduce the loss of current. In detail, mainly by forming a plurality of tab groups 200 at the end of the winding body 100, which can be one end of the winding body 100 or both ends of the winding body 100, and the selection is made according to the positive and negative poles of the battery cell, which is not specifically limited here. The plurality of tab groups 200 are arranged along the circumferential direction of the winding body 100, and the extension lines of the radial directions R of the two adjacent tab groups 200 intersect to form a first included angle, the angle range of the first included angle is 30° to 90°, mainly to avoid that the angle of the first included angle is too small to affect the flattening of the tab group 200, or the angle of the first included angle is too large to affect the efficiency of current introduction. The angle error range between the plurality of first included angles is 0° to 5°, so that the angle between the two adjacent tab groups 200 in the plurality of tab groups 200 and the arc distance along the circumferential direction tend to be equal, that is, the plurality of tab groups 200 tend to be arranged at equal arc distances along the circumferential direction, and the tab groups 200 are welded with the current collector to form a plurality of welding points 310, so that the plurality of welding points 310 on the adjacent tab groups 200 also tend to be arranged at equal arc distances along the circumferential direction, effectively improve the problem that the current loss is more in the flowing process due to the irregular distribution of the welding points 310, and is beneficial to improve the uniformity of the current introduction to the tab sheet 110 and reduce the current loss.

[0032] It should be noted that the angle error range between the plurality of first included angles is 0° to 5°, including both endpoints 0° and 5°. Within this angle range, the position of the welding point 310 and the uniformity of current inflow are less affected, which is conducive to taking into account the uniformity of current inflow and reducing the processing precision of the die-cutting tab 210. Of course, preferably, the angle error range between the plurality of first included angles is 0°, because although the angle error range is limited to a small range in this embodiment, as the number of winding turns increases, the position error of the die-cutting tab 210 distribution will be gradually magnified, so under the premise of conditions, it is preferred that the angle error range between the plurality of first included angles is 0°, thereby ensuring that the plurality of die-cutting tabs 210 along the radial direction R can be linearly arranged.

[0033] In some embodiments, referring to FIG. 1, FIG. 4 and FIG. 5, the tab group 200 includes a plurality of die-cutting tabs 210, which are integrally formed with the tab sheet 110 and located at the end of the winding body 100. Along the radial direction R, the plurality of die-cutting tabs 210 are linearly arranged. By linearly arranging the plurality of die-cutting tabs 210 along the radial direction R, it is easier to flatten the plurality of die-cutting tabs 210 along the radial direction R when the plurality of die-cutting tabs 210 are flattened, avoiding the plurality of die-cutting tabs 210 from being disordered in position when flattened, which makes it difficult to form the welding point 310 subsequently. Moreover, linearly arranging the plurality of die-cutting tabs 210 is also conducive to limiting the overall position of the welding point 310, preventing the welding point 310 from being too messy, improving the uniformity of current flow to some extent, and effectively reducing the additional path conduction of current in the tab sheet 110 for uniform distribution, reducing the energy loss caused by uneven current inflow into the tab sheet 110.

[0034] Further, the tab sheet 110 is wound multiple turns, and the number of die-cutting tabs 210 connected by each turn of the tab sheet 110 is equal. It should be noted that for each turn of winding, any radius of the winding body 100 is taken as the starting point of winding, and the position passing through the radius is taken as the endpoint of this turn and the starting point of the next turn until the winding passes through the radius for the first time. By limiting the number of die-cutting tabs 210 on each turn to be equal, and in combination with the aforementioned embodiment that the plurality of die-cutting tabs 210 are linearly arranged along the radial direction R, it can be deduced that as the number of winding turns increases, the arc distance between adjacent die-cutting tabs 210 in each turn along the winding direction gradually increases, thereby ensuring that the die-cutting tabs 210 on multiple turns can be linearly arranged along the radial direction R.

[0035] In some embodiments, referring to FIGS. 2 and 3, the pole piece 110 is wound for multiple turns, and the plurality of welding spots 310 are sequentially and spaced apart along the winding direction Q of the pole piece 110. On the same turn of the pole piece 110, the plurality of welding spots 310 are arranged at equal arc distances along the winding direction Q. By limiting the plurality of welding spots 310 on each turn to be arranged at equal arc distances, each welding spot 310 is located on the corresponding die-cut tab 210, and the welding spots 310 exhibit a certain regularity. The regularity is selected according to actual conditions. For example, the plurality of welding spots 310 on each turn can be arranged at equal arc distances and linearly arranged along the radial direction R, or the plurality of welding spots 310 on each turn can be arranged at equal arc distances and arranged in an arc shape along the radial direction R. In the present embodiment, the plurality of welding spots 310 are preferably arranged in an arc shape along the radial direction R, which is beneficial to reducing the difficulty of position determination when the plurality of welding spots 310 are formed.

[0036] Further, referring to FIGS. 1 and 3, the plurality of welding spots 310 form a plurality of welding spot groups 300, and the welding spots 310 in each welding spot group 300 are arranged in an arc shape along the radial direction R, so that the plurality of welding spots 310 in each welding spot group 300 all have a certain arrangement regularity. The specific arrangement regularity is to be arranged in an arc shape along the radial direction R, which is mainly to make it more convenient to determine the position of the welding spot 310. In detail, before the welding spot 310 is determined, the pole piece 110 has been wound to form a wound body 100 along the winding direction Q. Of course, the wound body 100 formed here also includes a separator, because the separator is wound together with the pole piece 110 and the structure and positional relationship of the separator are not involved in the present application, therefore, in the subsequent description of the winding of the wound body 100, in order to simplify, the description of the winding of the wound body 100 by the pole piece 110 is adopted. Based on the shape of the wound body 100, the positions and numbers of the welding spots 310 and the die-cut tabs 210 are simulated according to actual conditions. The simulation mode of the welding spot 310 is to determine the arc distance between adjacent welding spots 310 along the winding direction Q, and then the simulated welding spots 310 not located on the die-cut tab 210 are cancelled according to the position of the die-cut tab 210, so that the plurality of welding spots 310 on each turn are arranged at equal arc distances, and the position of the welding spot 310 is determined to be relatively simple and accurate. Further, a plurality of welding spot groups 300 are formed on each tab group 200, and the plurality of welding spot groups 300 are sequentially arranged along the radial direction R. For ease of understanding, the forming process of the entire die-cut tab 210 and the welding spot 310 is exemplified by parameters as follows:

[0037] In the embodiment, the inner diameter of the winding is 2.5 mm, the outer diameter is 40 mm, and the number of winding turns is 90; the arc distance between adjacent welding points 310 is 4 mm; the first included angle formed by the extension lines of the adjacent tab groups 200 in the radial direction R is 45°, and the angle error between the plurality of first included angles is 0°, that is, there is no angle error. First, according to the preset parameters, the shape of the winding body 100 with the tab groups 200 and the welding point track is simulated by using simulation software such as AutoCAD. The welding point track here needs to be divided into two steps: the first step is to form a plurality of welding points 310 according to the arc distance between adjacent welding points 310 along the winding direction Q, and the second step is to cancel the welding points 310 not located on the die-cut tab 210 according to the position of the plurality of tab groups 200, thereby obtaining the final welding point track for welding. At this time, the welding point track is crescent-shaped, and a plurality of crescent-shaped welding point groups 300 arranged in the radial direction R are formed on each tab group 200. According to the first included angle of 45° and the arc distance of 4 mm, it can be inferred that the first circle of welding point groups 300 arranged in the circumferential direction is obtained by canceling a group of welding points 310 between adjacent welding point groups 300, and the second circle of welding point groups 300 is obtained by canceling three groups of welding points 310 between adjacent welding point groups 300. In this way, the first circle of adjacent welding point groups 300 has an arc distance of 8 mm, the second circle of adjacent welding point groups 300 has an arc distance of 16 mm, the third circle of adjacent welding point groups 300 has an arc distance of 24 mm, and the fourth circle of adjacent welding point groups 300 has an arc distance of 32 mm. Because the welding point track is formed according to the equal arc distance of 4 mm and is located on the corresponding die-cut tab 210, the arc distance between the plurality of welding points 310 on each winding turn of the winding body 100 can be ensured to be equal, thereby improving the uniformity of current introduction between the die-cut tab and the tab sheet 110. As the number of winding turns increases and the number of welding points 310 increases, the crescent-shaped welding point group 300 is formed.

[0038] In some embodiments, among the plurality of welding point groups 300 on the adjacent two tab groups 200, two welding point groups 300 adjacent in the circumferential direction of the winding body 100 form a welding point group pair, and the distance between the two welding point groups 300 in each welding point group pair is positively correlated with the distance of the welding point group pair from the center of the winding body 100 in the radial direction R, that is, the farther from the center of the winding body 100, the greater the distance between the two adjacent welding points in the circumferential direction, and the distance increases linearly.

[0039] It should be noted that the distance between the two welding point groups 300 in the above embodiment refers to the distance between the centers of the two welding point groups 300, and the distance of the welding point group pair from the center of the winding body 100 in the radial direction refers to the distance of the center of the welding point group pair from the center of the winding body 100 in the radial direction.

[0040] By arranging the plurality of tab groups 200 in the circumferential direction (the first included angle is 45° and the angle error between the plurality of first included angles is 0°), the plurality of die-cut tabs 210 in each tab group 200 are linearly arranged in the radial direction R, the plurality of solder joint groups 300 on each die-cut tab 210 are also linearly arranged in the radial direction R, and the plurality of solder joints 310 on each solder joint group 300 are obtained by limiting the equal arc distance between adjacent solder joints 310 in each circle. The arrangement of the plurality of die-cut tabs 210 and the plurality of solder joints 310 has a certain regularity, thereby improving the uniformity of current flow between the die-cut tabs and the pole piece 110 and reducing current loss. In addition, because the plurality of tab groups 200 are arranged in the circumferential direction, the plurality of solder joints 310 are arranged on the corresponding tab groups 200. Compared with the technical solution of the full tab 400 and the plurality of solder joints 310 arranged on the full tab 400, the technical solution can reduce the risk of uneven current flow caused by uneven distribution of the solder joints 310. If a plurality of solder joints 310 are arranged on the full tab 400 in equal arc distance to improve the uniformity of current flow, compared with the way of arranging the solder joints 310 in equal arc distance on the full tab 400, the technical solution can also greatly reduce the number of solder joints 310, thereby improving the welding efficiency and saving the cost.

[0041] Further, along the circumferential direction, the arc distance between the two adjacent solder joint groups 300 is: D = n x s;

[0042] Wherein, D represents the arc distance between the two adjacent solder joint groups 300 in a solder joint group pair, n represents the number of sequentially arranged solder joint groups 300 in the radial direction of the winding body 100 and away from the center of the winding body 100, and s represents the arc distance between the two adjacent solder joints 310 in the first winding circle of the winding body 100. From the calculation formula of the arc distance between the two adjacent solder joint groups 300, it can be seen that the arc distance is proportional to the number of sequentially arranged solder joint groups 300 in the radial direction of the winding body 100 and away from the center of the winding body 100, and is also proportional to the arc distance between the two adjacent solder joints 310 in the first winding circle of the winding body 100.

[0043] In some embodiments, referring to FIG. 1 and FIG. 5, the cell welding structure further comprises a full tab 400, the full tab 400 is welded with the current collector to form a plurality of welding points 310, and the full tab 400 is located at one end of the winding body 100, and the tab group 200 is connected to the side of the full tab 400 away from the center of the winding body 100 and in the radial direction R. In detail, the winding body 100 is not die-cut at the part close to the center, such as the first three winding turns, so as to be used as a full tab 400, and die-cutting is performed according to the die-cut tab 210 forming mode in the foregoing embodiments after the three turns. It should be noted that for the part of the full tab 400, the determination of the welding point trajectory is still as follows: simulate the welding points 310 with equal arc distance along the winding direction Q, and then retain the welding point trajectory at the part of the tab group 200 extending along the radial direction R towards the winding center, and eliminate the remaining welding point trajectories. Thus, whether it is a full tab 400 or a die-cut tab 210, the welding point group 300 formed satisfies the linear arrangement in the radial direction R. By setting the part of the winding body 100 close to the center as a full tab 400, compared with using die-cut tabs 210 entirely, it is more conducive to forming a tab group 200 with linear shape, and it is also more conducive to the flattening of the die-cut tab 210.

[0044] Referring to FIG. 6, the application further provides a cell welding method, which is applied to the cell welding structure in any of the foregoing embodiments. The cell welding method comprises:

[0045] S1, obtaining winding parameters, welding parameters and die-cutting parameters, the winding parameters comprising an inner diameter, an outer diameter and a number of turns of winding, the welding parameters comprising an arc distance between adjacent welding points along the winding direction, and the die-cutting parameters comprising an included angle between adjacent tab groups along the circumferential direction of the winding body.

[0046] It should be noted that the winding parameters, the welding parameters and the die-cutting parameters are all set according to actual conditions, and in different situations and working conditions, the winding parameters, the welding parameters and the die-cutting parameters can all be changed. In this embodiment, the inner diameter of winding is 2.5 mm, the outer diameter is 40 mm, and the number of turns of winding is 90 turns; the arc distance between adjacent welding points 310 is 4 mm; the first included angle formed by the extension lines of adjacent tab groups 200 in the radial direction R is 45°, and the angle error between a plurality of first included angles is 0°, i.e. no angle error.

[0047] S2, simulating and outputting the winding shape and the welding trajectory of the cell welding structure according to the winding parameters, the welding parameters and the die-cutting parameters.

[0048] It should be noted that the simulation software here adopts AutoCAD. By inputting the winding parameters, welding parameters and die cutting parameters into AutoCAD, the shape of the winding body 100 after die cutting, winding and welding by the die cutting equipment, winding equipment and welding equipment respectively can be simulated. For the die cutting parameters, in addition to the above-mentioned angle-related parameters, the depth of die cutting can also be preset.

[0049] Further, the forming of the welding trajectory specifically includes:

[0050] S21, forming a preliminary winding body 100 shape according to the winding parameters and the die cutting parameters, the winding body 100 shape being a winding body 100 shape with the tab group 200 formed;

[0051] S22, marking welding points on the preliminary winding body 100 shape according to the welding parameters;

[0052] S23, eliminating the welding point marks not located on the tab group 200 according to the position of the tab group 200 to obtain the final welding point trajectory.

[0053] It should be noted that for the welding point marks, in order to facilitate the staff to intuitively observe the welding point trajectory, the welding point marks are represented by hollow dots in the simulation software, and the schematic of the welding point 310 in the drawing is also represented by a hollow dot. The shape of the welding point mark in the drawing is not a limitation of the actual shape of the welding point 310. The shape of the welding point 310 can be a dot, a square or other shapes, which are not limited.

[0054] S3, winding the pole piece connected with the tab group to form a winding body according to the winding shape. The winding equipment precisely winds according to the winding body shape simulated by the simulation software, so as to ensure that the welding points and the die cut tabs meet the expected requirements.

[0055] S4, determining the welding position between the tab group and the current collector and welding to form a plurality of welding points according to the welding trajectory. The welding equipment is welded one by one according to the welding trajectory simulated by the simulation software, so as to ensure that the number of welding points and the welding position meet the expected requirements.

[0056] The technical solution provided in the present application is mainly to set multiple tab groups 200 which are arranged at intervals along the circumferential direction of the winding body 100, and the angle error range between the multiple tab groups 200 is 0° to 5°, so that the multiple tab groups 200 tend to be arranged at equal angles along the circumferential direction, that is, tend to be arranged at equal arc distances, the tab groups 200 are welded with the current collector, so that the multiple welding points 310 are located on the tab groups 200, the distribution positions of the multiple welding points 310 are limited, the problem that the current is likely to flow from the welding points 310 to a longer path, affecting the current loss and the overcurrent performance is effectively improved, the regularity of the distribution of the welding points 310 is improved and the current loss is reduced. In detail, the multiple tab groups 200 are connected to one end of the winding body 100, the multiple tab groups 200 extend along the radial direction R of the winding body 100, are arranged at intervals along the circumferential direction, and the extension lines of the adjacent two tab groups 200 along the radial direction R intersect to form a first included angle, the angle error range between the multiple first included angles is 0° to 5°, so that the angle and the arc distance between the adjacent two tab groups 200 in the multiple tab groups 200 tend to be equal, that is, the multiple tab groups 200 tend to be arranged at equal arc distances along the circumferential direction, and the tab groups 200 are welded with the current collector to form the multiple welding points 310, so that the multiple welding points 310 are limited on the tab groups 200, and the multiple welding points 310 also tend to be arranged at equal arc distances along the circumferential direction, effectively improving the problem that the current loss is more in the flowing process due to the irregular distribution of the welding points 310, and being beneficial to improving the uniformity of the current flowing into the tab sheet 110 and reducing the current loss.

[0057] In addition, by arraying the multiple tab groups 200 along the circumferential direction, the multiple welding points 310 are all arranged on the corresponding tab groups 200, compared with the technical solution of the full tab 400 and the multiple welding points 310 arranged on the full tab 400, the present technical solution can reduce the risk of uneven current conduction caused by uneven distribution of the welding points 310, and if the multiple welding points 310 are arranged at equal arc distances on the full tab 400 to improve the uniformity of current conduction, compared with the way of arranging the welding points 310 at equal arc distances on the full tab 400, the present technical solution can also greatly reduce the number of welding points 310, thereby improving the welding efficiency and saving the cost.

[0058] The embodiment of the present application provides a battery comprising the cell welding structure in any of the foregoing embodiments. It should be noted that since the battery comprises the cell welding structure in any of the foregoing embodiments, the battery has the beneficial effects similar to or the same as the cell welding structure, and the derivation process of the specific beneficial effects is described in the embodiment of the cell welding structure, which will not be described here.

[0059] Also, certain terminology can also be used in the description for the sake of clarity. For example, the terms "some" and "one" can mean one or more than one. Additionally, terms such as "left," "right," "front," "back," "top," "bottom," "over," "under," "above," "below," "up," "down," "vertical," "horizontal," "side," "planar," "diagonal," and the like can be used herein just to simplify the description and are not intended to limit the concepts to a fixed spatial orientation. Further, "first," "second," "third," etc., can be used merely as labels, and are not intended to impose numerical requirements on their objects. Moreover, terms such as "front," "back," "top," "bottom," "up," "down," "vertical," "horizontal," "side," "planar," "diagonal," and the like can be used herein merely to simplify the description and are not intended to limit the concepts to a fixed spatial orientation. Moreover, terms such as "front," "back," "top," "bottom," "up," "down," "vertical," "horizontal," "side," "planar," "diagonal," and the like can be used herein merely to simplify the description and are not intended to limit the concepts to a fixed spatial orientation. It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Further, it is to be understood that terms such as "part," "section," "portion," "member," "segment," "element," "component," "module," "device," "mechanism," "assembly," "unit," and the like can refer to a single structure or multiple structures, and can be used interchangeably with "structure" or "structures." Finally, terms such as "above," "below," "upper," "lower," and the like are used to simplify the description and are not intended to limit the scope of the concepts to a fixed spatial orientation.

[0060] In some embodiments, numbers that describe amounts, dimensions, and so forth, are used in the description of the embodiments. It should be understood that such numbers are used to describe embodiments and, in some instances, are modified by the modifier "about" or "approximately." Unless otherwise specified, the "about" or "approximately" indicates that a value can vary from a nominal value by ± %. Accordingly, numerical parameters such as those outlined in the specification and claims are approximations and can vary depending upon the desired properties sought to be obtained by the particular embodiments. At the very least, it should be understood that a numerical value described for a given parameter has a range of values that fall around the measured value as does a stated value. In some embodiments, numerical values are approximations that can vary depending upon the requirements of a given embodiment. In some embodiments, numerical values should be considered in the context of the number of significant digits used for measurement and the acceptable error for measurement.

Claims

1. An electrode core welding structure, comprising: a winding body; a plurality of tab groups formed at an end of the winding body, the plurality of tab groups being arranged radially around a center of the winding body; a current collector welded to a side of the plurality of tab groups away from the winding body to form a plurality of welding points.

2. The cell weld structure of claim 1, wherein, The winding body has a circumferential direction and a radial direction, and along the circumferential direction, two adjacent tab groups intersect along an extension line of the radial direction to form a first included angle, the first included angle being in a range of 30° to 90°.

3. The cell weld structure of claim 2, wherein, An angle error between a plurality of the first included angles is in a range of 0° to 5°.

4. The cell weld structure of claim 3, wherein, The angle error between a plurality of the first included angles is 0°.

5. The cell weld structure of claim 3, wherein, Each of the tab groups includes a plurality of die-cut tabs, and the plurality of die-cut tabs in each of the tab groups are arranged linearly along the radial direction of the winding body.

6. The cell weld structure of claim 5, wherein, The winding body includes pole pieces arranged in a winding manner, and the pole pieces are integrally formed with the die-cut tabs.

7. The cell weld structure of claim 6, wherein, The pole pieces are wound for multiple turns, and the number of die-cut tabs connected by each turn of the pole pieces is equal.

8. The cell welding structure of claim 3 or 4, wherein The winding body includes pole pieces arranged in a winding manner, the pole pieces are integrally formed with the die-cut tabs, the pole pieces are wound for multiple turns, and the plurality of welding points are sequentially and spacedly arranged along the winding direction of the pole pieces.

9. The cell weld structure of claim 8, wherein, Along the winding direction, a plurality of the welding points are arranged at equal arc distances on the same turn of the pole pieces.

10. The cell welding structure of claim 8 or 9, wherein, The plurality of welding points form a plurality of welding point groups, and the welding points in each of the welding point groups are arranged in an arc shape along the radial direction.

11. The cell weld structure of claim 10, wherein, A plurality of the welding point groups are formed on each of the tab groups, and the plurality of welding point groups are sequentially arranged along the radial direction.

12. The cell weld structure of claim 11, wherein, Among a plurality of the welding point groups on two adjacent tab groups, two of the welding point groups adjacent in the circumferential direction of the winding body form a welding point group pair, and a distance between the two welding point groups in each of the welding point group pairs is positively correlated with a distance of the welding point group pair from the center of the winding body along the radial direction.

13. The cell weld structure of claim 12, wherein, An arc distance between the two welding point groups in each of the welding point group pairs is equal to a product of a number of the welding point groups sequentially arranged outward along the radial direction of the winding body and an arc distance between two adjacent welding points in a first turn of the winding body.

14. The cell weld structure of claim 13, wherein, A calculation formula of the arc distance between the two welding point groups in each of the welding point group pairs is D = n × s. Wherein, D represents an arc distance between two adjacent welding point groups in a welding point group pair, n represents a number of the welding point groups sequentially arranged outward along the radial direction of the winding body, and s represents an arc distance between two adjacent welding points in a first turn of the winding body.

15. The cell weld structure of any one of claims 1 to 14, wherein, The electrode core welding structure further comprises a full tab, the full tab is located at the same end of the winding body as the plurality of tab groups, and the full tab is arranged close to an inner turn of the winding body.

16. The cell weld structure of claim 15, wherein, The plurality of tab groups are located on a side of the full tab away from the center of the winding body and connected to the full tab, and the full tab and the plurality of tab groups are both welded to the current collector to form a plurality of the welding points.

17. The cell weld structure of any one of claims 2 to 16, wherein, The inner diameter of the winding body is 2.5 mm, the outer diameter is 40 mm, the number of winding turns is 90, the arc distance between adjacent welding points is 4 mm, the first included angle is 45°, and the angle error between a plurality of first included angles is 0°.

18. A cell welding method for manufacturing the cell welding structure according to any one of claims 1 to 17, comprising: obtaining winding parameters, welding parameters and die cutting parameters, the winding parameters including an inner diameter, an outer diameter and a number of turns of winding, the welding parameters including a direction of winding, an arc distance between adjacent welding points in each turn of winding, and the die cutting parameters including an included angle between two adjacent tab groups in a circumferential direction of the winding body; simulating and outputting a winding shape and a welding trajectory of the cell welding structure according to the winding parameters, the welding parameters and the die cutting parameters; winding a tab connected with the tab group to form a winding body according to the winding shape; determining welding positions between the tab group and the current collector and welding to form a plurality of welding points according to the welding trajectory.

19. The cell welding method of claim 18, wherein, The step of simulating and outputting a winding shape and a welding trajectory of the cell welding structure according to the winding parameters, the welding parameters and the die cutting parameters, comprises: forming a preliminary winding body shape according to the winding parameters and the die cutting parameters, the winding body shape being a shape formed with the tab group; performing welding point marking on the preliminary winding body shape according to the welding parameters; eliminating the welding point marking not located on the tab group according to the position of the tab group to obtain a welding point trajectory.

20. A battery comprising the cell welding structure according to any one of claims 1 to 17 or prepared by the cell welding method of claim 18 or 19.

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