Conducting bar structure for solving cold solder joint of laser penetration welding during single-side welding of cylindrical battery cell

Abstract

The utility model belongs to the technical field of cylindrical cell energy storage modules, and particularly discloses a conducting bar structure for solving insufficient welding of laser penetration welding during single-side welding of a cylindrical cell, the conducting bar structure is provided with a laser splicing seam welding part, a laser penetration welding part and a connecting part, and the laser splicing seam welding part and the laser penetration welding part are respectively connected to two ends of the connecting part. The laser splicing seam welding part extends in the vertical direction. In order to cut off a height step on the existing conducting bar structure, when laser penetration welding layers with the same thickness are formed on the laser penetration welding part and the end surfaces of the cylindrical battery cells by adopting laser penetration welding, the height difference between the end surfaces of the two adjacent cylindrical battery cells is transferred to the height difference between the initial position and the welding end of the negative pole column; and the height difference can be adjusted through related measures such as repair welding, so that the hidden danger of insufficient welding caused by laser penetration welding of the end face of the battery cell cover plate is avoided, and finally the situation that the cylindrical battery cell module loses efficacy due to disconnection of an electric connection path is avoided.

Description

Technical Field

[0001] This utility model belongs to the technical field of cylindrical battery cell energy storage module, specifically relating to the conductive busbar structure that solves the problem of incomplete welding during laser penetration welding of cylindrical battery cells on one side. Background Technology

[0002] Current cylindrical cell energy storage modules commonly use a PACK method, consisting of a series of cylindrical cells (such as...) Figure 1 , 2 As shown) arranged and assembled into a plastic bracket (such as Figure 3 As shown), the bottom surfaces of the cylindrical cells placed on the plastic support are at the same height to ensure that the cells are at the same horizontal height; in addition, the cylindrical cells are connected by conductive busbars (such as...). Figure 4 (As shown) connection, using single-sided welding of the battery cell assembly (e.g.) Figure 5 As shown), specifically: one end of the conductive busbar is laser-welded to the negative electrode of the cylindrical cell, and the other end is laser-welded to the cell cover of the adjacent cylindrical cell; these are then combined in series and parallel to form a large energy storage module (such as...). Figure 6 (As shown).

[0003] However, on the one hand, height tolerances arise during the manufacturing of individual battery cells; on the other hand, the gap between the two welding overlap surfaces (conductor busbar and cell cover plate) of laser penetration welding must be <0.15mm. Currently, the height tolerance of a single cylindrical cell is ±0.3mm. When the gap between the two welding overlap surfaces (conductor busbar and cell cover plate) of laser penetration welding exceeds 0.15mm (i.e., the requirement for the gap between the laser penetration welding overlap surfaces is <0.15mm), there is a significant risk of incomplete soldering, which can lead to electrical connection failure in the module product.

[0004] For example: Figure 7 As shown, there is no height difference between adjacent cells and the gap between the welding lap surfaces is 0. At this time, laser penetration welding will not cause a false weld between the conductive busbar and the cell cover plate.

[0005] like Figure 8 As shown, there is a height difference between adjacent cells, that is, the end face of the second cell cover plate of two adjacent cylindrical cells is higher than the end face of the first cell cover plate. At this time, the poor soldering between the busbar and the cell cover plate may pose a risk of electrical connection failure.

[0006] like Figure 9 As shown, there is a height difference between the cylindrical surfaces of adjacent cells, that is, the end face of the first cell cover plate of two adjacent cylindrical cells is higher than the end face of the second cell cover plate. In this case, laser penetration welding will not cause a false weld between the conductive busbar and the cell cover plate. Utility Model Content

[0007] This utility model provides a conductive busbar structure to solve the problem of laser penetration welding failure when welding a cylindrical cell on one side. The height difference of the original cylindrical cell surface is transferred to the height difference of the electrode welding end. That is, the height difference of the electrode end face welding can be adjusted by repair welding and other related measures to avoid the hidden danger of electrical connection failure.

[0008] The technical problem to be solved by this utility model is achieved by the following technical solution:

[0009] A conductive bus structure is provided to address the issue of incomplete laser penetration welding during single-sided welding of cylindrical battery cells. The conductive bus structure comprises a laser-welded seam, a laser-penetrating weld, and a connecting portion. The laser-welded seam and the laser-penetrating weld are respectively connected to opposite ends of the connecting portion. The thickness direction of the laser-welded seam extends vertically. The laser-welded seam and the connecting portion are continuous and form a step vertically. The laser-welded seam is thinner than the connecting portion, and the upper surface of the laser-welded seam is coplanar with the upper surface of the connecting portion.

[0010] Preferably, the laser splicing seam weld, the connecting part, and the laser penetration weld are integrally formed.

[0011] Preferably, the laser-welded seam is connected to the negative terminal of the cylindrical cell, and the laser-penetrating weld is connected to the end face of the cell cover plate of the cylindrical cell adjacent to the cylindrical cell, and the negative terminal of each cylindrical cell is located on the end face of the cell cover plate of the same cylindrical cell.

[0012] Preferably, the laser-welded seam is connected to the negative terminal of the cylindrical cell via laser-welded seam, and the laser-penetrating weld is connected to the end face of the cell cover plate of the cylindrical cell adjacent to the cylindrical cell via laser-penetrating weld.

[0013] The material welded between the negative electrode post and the laser splicing seam weld is used as the laser splicing seam weld layer, and the material welded between the end face of the battery cell cover and the laser penetration weld is used as the laser penetration weld layer.

[0014] Preferably, a negative electrode plastic insulating ring is fitted onto the portion of the negative electrode post extending beyond the end face of the cell cover plate. This negative electrode plastic insulating ring is connected to the end face of the cell cover plate and has a predetermined protrusion height. Two adjacent end faces of the cell cover plate are respectively designated as the first end face of the cell cover plate and the second end face of the cell cover plate. The position where the laser splicing seam weld begins to extend is designated as the starting position. The distance from the starting position to the top of the negative electrode plastic insulating ring decreases sequentially in the following order: the height of the first end face of the cell cover plate is higher than that of the second end face of the cell cover plate; the height of the first end face of the cell cover plate is equal to that of the second end face of the cell cover plate; and the height of the second end face of the cell cover plate is higher than that of the first end face of the cell cover plate. That is, the thickness h2 of the laser splicing seam weld layer decreases sequentially, while the thickness h1 of the laser-penetrated weld remains unchanged.

[0015] Preferably, when the end face of the second cell cover plate is higher than the end face of the first cell cover plate, the gap between the laser splice weld and the upper surface of the negative electrode plastic insulation ring is 0.

[0016] Preferably, the gap between the laser-penetrating weld and the end face of the first cell cover plate is O.

[0017] The beneficial effects of this utility model are:

[0018] (1) The conductive bus structure of this utility model has a laser splicing seam weld, a laser penetration weld and a connecting part. The laser splicing seam weld and the laser penetration weld are respectively connected to the opposite ends of the connecting part. The thickness direction of the laser splicing seam weld extends in the vertical direction. The laser splicing seam weld and the connecting part are continuous and form a step in the vertical direction. The laser splicing seam weld is thinner than the connecting part, and the upper surface of the laser splicing seam weld is coplanar with the upper surface of the connecting part. The purpose here is to cut out a height step on the existing conductive bus structure. When the laser penetration weld and the cylindrical cell end face are laser penetrated to form a laser penetration weld layer of the same thickness, the height difference between the two adjacent cylindrical cell end faces is transferred to the height difference between the initial position and the negative electrode post welded to one end. This height difference can be adjusted by supplementary welding and other related measures, thereby avoiding the risk of false welding in the laser penetration welding of the cell cover end face, and ultimately avoiding the failure of the cylindrical cell module due to the disconnection of the electrical connection path.

[0019] (2) This utility model places several cylindrical cells in the mounting slot of the mounting bracket. There is a height difference or flushness between the end faces of the cell cover plates on adjacent cylindrical cells. Therefore, a conductive bus structure is installed on two adjacent cylindrical cells. The main feature is that the laser splicing weld has a negative electrode post sleeve hole. The laser splicing weld is sleeved on the negative electrode post through the negative electrode post sleeve hole. The laser splicing weld layer is welded in the gap between the starting position and the top of the negative electrode plastic insulation ring. The laser penetration weld layer is welded in the gap between the laser penetration weld and the top of the end face of another cell cover plate.

[0020] Based on the height difference between the end faces of the first and second cell cover plates, laser splicing welding layers of different thicknesses are used, while the thickness of the laser-penetrated welding layer remains constant. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural diagram of a cylindrical battery cell;

[0022] Figure 2 This is a front view of a cylindrical battery cell;

[0023] Figure 3 A schematic diagram of the mounting bracket for installing cylindrical battery cells;

[0024] Figure 4 This is a schematic diagram of a conductive bus structure in the prior art;

[0025] Figure 5 This is a schematic diagram of a structure in the prior art where adjacent battery cells are connected by a conductive busbar structure and then mounted on a mounting bracket.

[0026] Figure 6 This is a three-dimensional structural diagram of an energy storage module PACK in the prior art;

[0027] Figure 7 This is a front view of two adjacent cylindrical cells connected by a conductive busbar structure in the prior art and then mounted on a mounting bracket when the height of the end face of the first cell cover plate is equal to that of the end face of the second cell cover plate.

[0028] Figure 8 This is a front view of two adjacent cylindrical cells connected by a conductive busbar structure in the prior art and then mounted on a mounting bracket when the height of the first cell cover plate end face is lower than the end face of the second cell cover plate.

[0029] Figure 9 This is a front view of two adjacent cylindrical cells connected by a conductive busbar structure in the prior art and then mounted on a mounting bracket when the height of the first cell cover plate end face is equal to that of the second cell cover plate end face.

[0030] Figure 10 This is a schematic diagram of the conductive bus structure in this utility model;

[0031] Figure 11 This is a front view of two adjacent cylindrical cells connected by the conductive busbar structure in this invention and then mounted on the mounting bracket when the height of the end face of the first cell cover plate is equal to that of the end face of the second cell cover plate.

[0032] Figure 12 This is a front view of two adjacent cylindrical cells connected by the conductive busbar structure in this utility model and then mounted on the mounting bracket when the height of the first cell cover plate end face is lower than the end face of the second cell cover plate.

[0033] Figure 13 This is a front view of two adjacent cylindrical cells connected by the conductive busbar structure in this invention and then mounted on the mounting bracket when the height of the first cell cover plate end face is equal to that of the second cell cover plate end face.

[0034] In the figure: 1. Conductor bus structure; 11. Laser splicing seam weld; 111. Initial position; 112. Ending position; 12. Connecting part; 121. First surface of connecting part; 122. Second surface of connecting part; 13. Laser penetration weld; 2. Cylindrical cell; 21. Negative electrode post; 22. Positive electrode post; 23. End face of cell cover plate; 231. End face of first cell cover plate; 232. End face of second cell cover plate; 24. Negative electrode plastic insulating ring; 3. Laser splicing seam weld layer; 4. Laser penetration weld layer; 5. Mounting bracket; 51. Mounting groove. Detailed Implementation

[0035] To facilitate a clear understanding of the technical means, creative features, objectives, and effects of this utility model, the following description, in conjunction with specific illustrations, further elaborates on this utility model.

[0036] like Figure 1 , 2 As shown in Figures 10-13, a conductive bus structure is provided to address the issue of incomplete laser penetration welding during single-sided welding of cylindrical battery cells. The conductive bus structure 1 includes a laser-welded seam 11, a laser-penetrating weld 13, and a connecting portion 12. The laser-welded seam 11 and laser-penetrating weld 13 are respectively connected to the two ends of the connecting portion 12. The laser-welded seam 11 extends vertically and is continuous with the connecting portion 12, forming a step in the vertical direction. The laser-welded seam 11 is thinner than the connecting portion 12, and the upper surface of the laser-welded seam 11 is coplanar with the upper surface of the connecting portion 12. Specifically, the laser-welded seam 11 is... The position where the welded part 11 begins to extend is designated as the starting position 111, and the position where the laser-jointed welded part 11 is completed is designated as the ending position 112. The connecting part 12 has two horizontal planes in the vertical direction, and both horizontal planes are parallel to the ending position 112 and the starting position 111. The two horizontal planes are designated as the first surface 121 and the second surface 122 of the connecting part, respectively. The first surface 121 of the connecting part is higher than the second surface 122 of the connecting part. The surface where the starting position 111 is located is higher than the second surface 122 of the connecting part in the vertical direction, and the surface where the ending position 112 is located is at the same height as the first surface 121 of the connecting part.

[0037] With the cylindrical cell 2 facing forward, i.e., the negative terminal 21 is located above the positive terminal 22, the initial position 111 is the bottom of the laser splicing weld 11, and the second surface 122 of the connecting part is the bottom surface of the connecting part 12; the final position 112 is the top of the laser splicing weld 11, and the first surface 121 of the connecting part is the top surface of the connecting part 12. At this time, the initial position 111 is higher than the bottom surface of the connecting part 12, and the height of the final position 112 is the same as the height of the top surface of the connecting part 12.

[0038] The laser-welded seam part 11, the connecting part 12, and the laser-penetrating weld part 13 are integrally formed.

[0039] The laser-welded seam 11 is connected to the negative electrode post 21 of the cylindrical cell 2, and the laser-penetrating weld 13 is connected to the cell cover end face 23 of the cylindrical cell 2 adjacent to the cylindrical cell 2. The negative electrode post 21 of each cylindrical cell 2 is located on the cell cover end face 23 of the same cylindrical cell 2.

[0040] The laser splicing seam weld 11 is connected to the negative electrode post 21 of the cylindrical cell 2 by laser splicing seam weld, and the laser penetration weld 13 is connected to the end face 23 of the cell cover plate of the cylindrical cell 2 adjacent to the cylindrical cell 2 by laser penetration weld.

[0041] The material welded between the negative electrode post 21 and the laser splicing weld 11 is used as the laser splicing weld layer 3, and the material welded between the end face 23 of the battery cell cover and the laser penetration weld 13 is used as the laser penetration weld layer 4.

[0042] The portion of the negative electrode post 21 extending beyond the end face 23 of the cell cover plate is fitted with a negative electrode plastic insulating ring 24. This negative electrode plastic insulating ring 24 is connected to the end face 23 of the cell cover plate and has a constant height value h. Two adjacent end faces 23 of the cell cover plate are respectively designated as the first end face 231 and the second end face 232 of the cell cover plate. The height of the initial position 111 from the negative electrode plastic insulating ring 24 decreases sequentially in the following order: the height of the first end face 231 is higher than the height of the second end face 232; the height of the first end face 231 is equal to the height of the second end face 232; and the height of the second end face 232 is higher than the height of the first end face 231. That is, the thickness h2 of the laser splicing weld layer 3 decreases sequentially, while the thickness h1 of the laser-penetrated weld part 4 remains unchanged.

[0043] When the height of the second cell cover end face 232 is higher than the height of the first cell cover end face 231, the gap between the laser splicing weld 3 and the upper surface of the negative electrode plastic insulating ring 24 is 0.

[0044] The gap between the laser-penetrating weld 4 and the end face 231 of the first cell cover plate is O.

[0045] This utility model connects the conductive busbar structure to the end faces of two adjacent battery cell cover plates in the following manner:

[0046] Several cylindrical cells 1 are placed in the mounting groove 51 of the mounting bracket 5. The end faces 23 of the cell cover plates on adjacent cylindrical cells 1 have a height difference or are flush. Therefore, a conductive bus structure is installed on two adjacent cylindrical cells. The main feature is that the laser splicing weld part 11 has a negative electrode post sleeve hole. The laser splicing weld part 11 is sleeved on the negative electrode post 21 through the negative electrode post sleeve hole. The laser splicing weld layer 3 is welded in the gap between the initial position 111 and the top of the negative electrode plastic insulating ring 24. The laser penetration weld layer 4 is welded in the gap between the laser penetration weld part 13 and the top of the end face of another cell cover plate.

[0047] Based on the height difference between the end face 231 of the first cell cover plate and the end face 232 of the second cell cover plate, laser splicing welding layers 3 of different thicknesses are used respectively, while the thickness of the laser penetration welding layer 4 remains unchanged.

[0048] It should also be noted that, compared with the existing conductive bus structure, the conductive bus structure in this utility model has a step cut out in the laser splicing seam weld 11.

[0049] The degree of bending between the connecting part and the laser-penetrating weld is large. More bending directly results in an additional height difference of h4 in the laser splicing weld 11. This height difference will affect the weld strength, reducing the original weld strength of height h to h-h4. The strength of the laser splicing weld 11 is also weakened. Therefore, this method should be abandoned and the solution adopted in this utility model is to cut a step in the laser splicing weld 11 to implement this solution.

[0050] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A conductive bus structure for solving the problem of incomplete laser penetration welding during single-sided welding of cylindrical battery cells, the conductive bus structure having a laser-welded seam, a laser-penetrating weld, and a connecting part, characterized in that: The laser-welded seam and the laser-penetrating weld are respectively connected to the opposite ends of the connecting part. The thickness direction of the laser-welded seam extends in the vertical direction. The laser-welded seam is continuous with the connecting part and forms a step in the vertical direction. The laser-welded seam is thinner than the connecting part, and the upper surface of the laser-welded seam is coplanar with the upper surface of the connecting part.

2. The conductive bus structure according to claim 1, characterized in that: The laser-welded seam is connected to the negative terminal of the cylindrical cell, and the laser-penetrating weld is connected to the end face of the cell cover plate of the cylindrical cell adjacent to the cylindrical cell. The negative terminal of each cylindrical cell is located on the end face of the cell cover plate of the same cylindrical cell.

3. The conductive bus structure according to claim 2, characterized in that: The laser-welded seam is connected to the negative terminal of the cylindrical cell via laser-welded seam, and the laser-penetrating weld is connected to the end face of the cell cover plate of the cylindrical cell adjacent to the cylindrical cell via laser-penetrating weld. The material welded between the negative electrode post and the laser splicing seam weld is used as the laser splicing seam weld layer, and the material welded between the end face of the battery cell cover and the laser penetration weld is used as the laser penetration weld layer.

4. The conductive bus structure according to claim 3, characterized in that: A negative electrode plastic insulating ring is fitted onto the portion of the negative electrode post extending beyond the end face of the cell cover plate. This negative electrode plastic insulating ring is connected to the end face of the cell cover plate and has a predetermined protrusion height. Two adjacent end faces of the cell cover plate are respectively designated as the first end face of the cell cover plate and the second end face of the cell cover plate. The position where the laser splicing seam weld begins to extend is designated as the starting position. The distance from the starting position to the top of the negative electrode plastic insulating ring decreases sequentially in the following order: the height of the first end face of the cell cover plate is higher than that of the second end face of the cell cover plate; the height of the first end face of the cell cover plate is equal to that of the second end face of the cell cover plate; and the height of the second end face of the cell cover plate is higher than that of the first end face of the cell cover plate. That is, the thickness h2 of the laser splicing seam weld layer decreases sequentially, while the thickness h1 of the laser-penetrated weld remains unchanged.

5. The conductive bus structure according to claim 4, characterized in that: When the end face of the second cell cover plate is higher than the end face of the first cell cover plate, the gap between the laser splicing weld and the upper surface of the negative electrode plastic insulation ring is 0.

6. The conductive bus structure according to claim 4 or 5, characterized in that: The gap between the laser-penetrating weld and the end face of the first cell cover plate is O.

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