Battery and Laser Welding System

Abstract

The present application provides a battery comprising a housing (1) having an opening (11) and a cover plate (2) covering the opening (11), the cover plate (2) having an end side (21) facing the opening (11) and an outer peripheral edge (22) connected to an opening peripheral edge (12) of the housing (1) surrounding the opening (11), at least a portion of a peripheral section of the outer peripheral edge (22) having a first side welding zone (221), at least a portion of a peripheral section of the opening peripheral edge (12) having a second side welding zone (121), and the first side At least one of the face welding zone (221) and the second side welding zone (121) is formed by a weld seam shape control structure (3), and the first side welding zone (221) and the second side welding zone (121) are welded together via a weld seam (5) by a laser (4) irradiated along the side from the outside, and the weld seam shape control structure (3) is configured to control the shaping of the weld seam during welding so that the maximum side outer dimension of the weld seam (5) does not exceed the maximum side outer dimension of the area corresponding to the weld seam (5) before welding. A laser welding system is further provided. The shaping of the weld seam can be controlled to avoid oversizing.

Description

[Technical Field]

[0001] This application relates to batteries, particularly lithium-ion batteries, and corresponding laser welding systems.

[0002] Background technology With technological advances and increasingly stringent environmental protection requirements, more and more devices are using batteries as power sources. For example, in recent years, the development of electric vehicles has progressed rapidly, and they are gradually replacing traditional vehicles.

[0003] Several batteries can form a module, and a module can form a battery pack. As an electrical energy storage unit, a battery must have a high energy density to store as much electrical energy as possible. Battery life is also one of the most important factors, since damage to any one battery can damage the entire battery pack.

[0004] The manufacturing method of a battery not only affects the quality of the battery itself, but also determines the manufacturing efficiency. Since battery packs usually contain a large number of batteries, selecting an efficient manufacturing method is particularly important. In the battery manufacturing process, a critical step is sealing and welding the battery cover plates.

[0005] Because many batteries must be arranged to form a module, the accuracy of the external dimensions, particularly the accuracy of the maximum side dimension of the batteries, is very important, and it is particularly important to prevent the maximum side dimension from increasing due to welding of the cover plate to the housing, as this would make it impossible to arrange the batteries in the expected format. This is particularly important in the case of horizontal welding.

[0006] For the above reasons, corresponding improvements are needed.

[0007] Summary of the Invention To overcome one of the above-mentioned drawbacks and / or other possible drawbacks in the prior art not mentioned herein, it is an object of the present application to provide an improved battery and corresponding laser welding system.

[0008] According to a first aspect of the present application, there is provided a battery comprising a housing having an opening and a cover plate covering the opening, the cover plate having an end side facing the opening and an outer peripheral edge connected to an opening peripheral edge of the housing surrounding the opening, at least a portion of the peripheral section of the outer peripheral edge having a first side welding zone and at least a portion of the peripheral section of the opening peripheral edge having a second side welding zone, at least one of the first side welding zone and the second side welding zone being formed with a weld seam shape control structure, the first side welding zone and the second side welding zone being welded together via a weld seam by a laser irradiated along a side from the outside, and the weld seam shape control structure being configured to control the shape of the weld seam during welding so that the maximum side outer dimension of the weld seam does not exceed the maximum side outer dimension of a corresponding region corresponding to the weld seam before welding.

[0009] According to an optional embodiment of the present application, the weld seam shape control structure is formed on the outer side surface of the first side welding zone and / or the second side welding zone.

[0010] According to any embodiment of the present application, the outer peripheral edge has an end surface portion that is disposed on the end surface of the opening peripheral edge and is consequently welded to the end surface, and the weld seam shape control structure is disposed adjacent to the end surface portion and / or the end surface.

[0011] According to an optional embodiment of the present application, the weld seam shape control structure includes a side recess structure in the first side welding zone and / or the second side welding zone that is recessed at least partially along the side relative to an outermost point of a corresponding area corresponding to the weld seam before welding.

[0012] According to an optional embodiment of the present application, the side recess structure includes a first side recess structure formed on the outer periphery and / or a second side recess structure formed on the opening periphery.

[0013] According to an optional embodiment of the present application, the outer periphery has a portion of an exposed side surface in which a first side recess structure is formed.

[0014] According to an optional embodiment of the present application, the second side recess structure is formed by recessing the outer surface of the side wall of the housing along the side at least partially relative to the outermost point of the corresponding area corresponding to the weld seam before welding.

[0015] According to an optional embodiment of the present application, the outer periphery has a buried portion buried in the opening, the buried portion forming a step with the end surface portion.

[0016] According to optional embodiments of the present application, the first lateral recess structure is formed by laterally recessing the entire exposed lateral portion and / or by a partial lateral recess structure formed in the exposed lateral portion.

[0017] According to an optional embodiment of the present application, the second side recess structure includes a recessed area extending on the side wall of the housing in a direction away from the end face.

[0018] According to an optional embodiment of the present application, at least a portion of the embedded portion is welded to the sidewall by a laser.

[0019] According to an optional embodiment of the present application, the partial side recession structure includes at least one of a step, a groove, and a bevel.

[0020] According to an optional embodiment of the present application, the recessed region extends away from the end face to the other end of the side wall opposite the end face.

[0021] According to an optional embodiment of the present application, a step and / or a groove is formed on at least one of the two edges of the exposed side portion.

[0022] According to an optional embodiment of the present application, the bevel is configured in a chamfered form.

[0023] According to an optional embodiment of the present application, the second side recess structure is formed by recessing the entire outer surface of the side wall of the housing relative to the outermost point of the corresponding area corresponding to the weld seam before welding.

[0024] According to an optional embodiment of the present application, the weld seam shape control structure is formed to surround the outer periphery and / or the opening periphery.

[0025] According to any embodiment of the present application, the weld seam shape control structure is formed by a gradual change from the arc welding start point to the arc welding end point.

[0026] According to an optional embodiment of the present application, the weld seam shape control structure is formed only at the arc welding starting point.

[0027] According to any embodiment of the present application, the weld seam shape control structures are formed only at the outer periphery and / or the peripheral corners of the opening periphery.

[0028] According to an optional embodiment of the present application, the battery is configured in a rectangular parallelepiped shape.

[0029] According to an optional embodiment of the present application, the housing and / or the cover plate are made of an aluminum alloy.

[0030] According to an optional embodiment of the present application, the battery is a lithium ion battery.

[0031] According to an optional embodiment of the present application, the housing and / or the cover plate are configured to be formed by stamping.

[0032] According to an optional embodiment of the present application, the cover plate is welded to the housing with the opening of the housing facing downwards.

[0033] According to an optional embodiment of the present application, the weld seam shape control structure is configured to be formed simultaneously with stamping of the housing and / or cover plate.

[0034] According to a second aspect of the present application, there is provided a laser welding system for a battery according to any of the above embodiments, the laser welding system including a fixed welding head and a controller, the controller being configured to cause the fixed welding head to start welding from a position having a weld seam shape control structure and to weld the cover plate to the housing.

[0035] According to some exemplary embodiments of the present application, at least one of the following advantages can be achieved or provided, namely, the formation of the weld seam can be controlled, in particular in terms of avoiding the impact of uncontrolled and oversized weld seam protrusions on the compact arrangement of adjacent cells, and in addition, it can be easily implemented by simple changes in the structure, shape, or even size, in particular of the housing and / or cover plate.

[0036] The principles, features, and advantages of the present application may be better understood by reading the following more detailed description of the application when taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0037] [Figure 1] FIG. 2 is a partial perspective cross-sectional view of a housing and cover plate of a battery prior to welding, according to an exemplary embodiment of the present application. [Figure 2]2 shows a perspective view of the battery housing and cover plate shown in FIG. 1 after being partially welded, where the weld seam on the left is formed by horizontal welding of an exemplary structural configuration according to the present application, and for comparison, a weld seam formed without said exemplary structural configuration is shown in phantom on the right. [Figure 3] 1 is a cross-sectional view of a battery housing and cover plate prior to welding, with the main area of ​​the present application generally enclosed by a dotted circle, according to an exemplary embodiment of the present application; [Figure 4] 4 is a cross-sectional view of a housing and cover plate of a battery prior to welding according to another exemplary embodiment of the present application, illustrating a weld seam shape control structure different from that of FIG. 3. [Figure 5] 10A-10C are cross-sectional views of a battery housing and cover plate prior to welding, with partial side setback structures in several possible configurations, according to other different exemplary embodiments of the present application; [Figure 6] 10A-10C are cross-sectional views of a battery housing and cover plate prior to welding, with partial side setback structures in several possible configurations, according to other different exemplary embodiments of the present application; [Figure 7] 10A-10C are cross-sectional views of a battery housing and cover plate prior to welding, with partial side setback structures in several possible configurations, according to other different exemplary embodiments of the present application; [Figure 8] 10A-10C are cross-sectional views of a battery housing and cover plate prior to welding, with partial side setback structures in several possible configurations, according to other different exemplary embodiments of the present application; [Figure 9] 10A-10C are cross-sectional views of a battery housing and cover plate prior to welding, with partial side setback structures in several possible configurations, according to other different exemplary embodiments of the present application; [Figure 10] 4A and 4B are diagrams illustrating a welding method according to an exemplary embodiment of the present application, taking the structural configuration of FIG. 3 as an example.

[0038] MODE FOR CARRYING OUT THE INVENTION In order to more clearly understand the technical problems, technical solutions, and advantageous technical effects of the present application, the present application will be described in more detail in conjunction with drawings and some exemplary embodiments. It should be understood that the specific embodiments described herein are for the purpose of illustrating the present application, rather than limiting the scope of the present application. The drawings are not necessarily drawn to scale for clarity.

[0039] FIG. 1 is a partial perspective cross-sectional view of a battery housing and cover plate prior to welding in accordance with an exemplary embodiment of the present application.

[0040] FIG. 2 shows a perspective view of the battery housing and cover plate shown in FIG. 1 after being partially welded, with the weld seam on the left being formed by a horizontal weld of an exemplary structural configuration according to the present application, and for comparison, a weld seam formed without said exemplary structural configuration is shown in phantom on the right.

[0041] FIG. 3 is a cross-sectional view of a battery housing and cover plate prior to welding in accordance with an exemplary embodiment of the present application, with the main area of ​​the present application generally enclosed by a dotted circle.

[0042] Referring to FIG. 3 , according to one embodiment of the present application, a battery is provided, the battery comprising: a housing 1 (the bottom of which is closed as shown in FIG. 3 ) having an opening 11; and a cover plate 2 for covering the opening 11, the cover plate 2 having an end side 21 facing the opening 11 and an outer peripheral edge 22 connected to an opening peripheral edge 12 of the housing 1 surrounding the opening 11, at least a portion of a peripheral section of the outer peripheral edge 22 having a first side weld zone 221, and at least a portion of a peripheral section of the opening peripheral edge 12 having a second side weld zone 222. The welding seam shape control structure 3 is configured to control the formation of the weld seam during welding so that the maximum side outer dimension of the weld seam 5 does not exceed the maximum side outer dimension of the corresponding region corresponding to the weld seam 5 before welding, and at least one of the first side welding zone 221 and the second side welding zone 121 is formed by a weld seam shape control structure 3, and the first side welding zone 221 and the second side welding zone 121 are welded together via a weld seam 5 (see Figure 2) by a laser 4 that is irradiated along the side from the outside, and the weld seam shape control structure 3 is configured to control the formation of the weld seam during welding so that the maximum side outer dimension of the weld seam 5 does not exceed the maximum side outer dimension of the corresponding region corresponding to the weld seam 5 before welding.

[0043] In other words, the use of the weld seam shape control structure 3 ensures that the maximum outer side dimension of the final weld seam 5 does not exceed the initial maximum outer side dimension of the area where the weld seam is located before welding, so that the pre-designed critical dimensions of the side are not changed by welding, avoiding adverse effects on the subsequent battery assembly or placement process. Therefore, no additional processing steps, such as rolling, are required later to trim the weld seam 5.

[0044] For example, as shown in FIG. 2, the weld seam 5 on the left side is formed due to the presence of the weld seam shape control structure 3, and in this case, the lateral dimension of the lateral side does not expand outward beyond the initial maximum lateral outer dimension of the same region (as can be seen by comparison with the region located behind the unwelded weld seam 5 on the left side of FIG. 2). Conversely, as a result of the absence of the weld seam shape control structure 3, the dimension of the weld seam region at the corresponding location on the right side expands outward to the side, exceeding the initial maximum lateral outer dimension of this region. Note that the weld seam on the right side of FIG. 2 is presented here hypothetically for comparison purposes.

[0045] It should also be noted that the terms "end" and "side" are used in a relative sense to help clearly define the relative orientation between different structures or parts, as can be clearly understood by those skilled in the art.

[0046] 1 to 3, according to an exemplary embodiment of the present application, the weld seam shape control structure 3 is formed on the outer side surface of the first side welding zone 221 and / or the second side welding zone 121. In other words, the weld seam shape control structure 3 is located at an exposed position on the side facing the laser 4 for the convenience of forming processing. However, a person skilled in the art will understand that the weld seam shape control structure 3 does not need to be exposed to the outside as long as the formation of the weld seam 5 can be controlled.

[0047] 3 , the outer peripheral edge 22 has an end surface portion 222 that is disposed on the end surface 122 of the opening peripheral edge 12 and is consequently welded to the end surface 122, and the weld seam shape control structure 3 is disposed adjacent to the end surface portion 222 and / or the end surface 122. That is, the weld seam shape control structure 3 may be disposed adjacent to the interface that is to be cut by laser welding, so as to provide a better effect.

[0048] To avoid uncontrolled side buildup on the side, the shape of the weld seam can be controlled by providing a relatively recessed structure / area that can accommodate molten material during the welding process. For example, according to an exemplary embodiment of the present application, as shown in FIG. 3 , the weld seam shape control structure 3 includes a side recessed structure 31 that is at least partially recessed along the side in the first side welding zone 221 and / or the second side welding zone 121 relative to the outermost point of the corresponding area corresponding to the weld seam 5 before welding. The side recessed structure 31 can be formed by a subtractive manufacturing process.

[0049] It can be appreciated that the textured surface formed in the weld area by the subtractive manufacturing process can also increase the laser absorption of the housing 1 and / or cover plate 2, improve welding consistency, reduce welding spatter, lower welding heat input, and reduce part deformation.

[0050] As shown in FIG. 3, the side recess structure 31 includes a first side recess structure 311 formed in the outer periphery 22 .

[0051] FIG. 4 shows a weld seam shape control structure 3 according to another exemplary embodiment of the present application.

[0052] Unlike the exemplary embodiment shown in FIG. 3, the side recess structure 31 shown in FIG. 4 includes a second side recess structure 312 formed in the opening periphery 12 .

[0053] Those skilled in the art will understand that in principle the first lateral recess structure 311 and the second lateral recess structure 312 can exist simultaneously.

[0054] 3, according to another exemplary embodiment of the present application, the outer peripheral edge 22 has an exposed side portion 223 in which a first side recess structure 311 is formed. In other words, the first side recess structure 311 is completely exposed to the outside.

[0055] 4 , according to another exemplary embodiment of the present application, the second side recess structure 312 is formed by laterally recessing the outer surface 131 of the side wall 13 of the housing 1 at least partially relative to the outermost point of the corresponding area corresponding to the weld seam 5 before welding. In this case, the second side recess structure 312 is achieved by controlling the outer surface 131 of the side wall 13 of the housing 1. This can be achieved by corresponding control of the dimensions of the housing 1.

[0056] Preferably, the second side recess structure 312 includes a recessed area extending on the side wall 13 of the housing 1 in a direction away from the end face 122. In particular, the recessed area extends in a direction away from the end face 122 from the end face 122 to the other end of the side wall 13 opposite the end face 122 (i.e., the bottom end in the figure). Such a recessed area may be a localized recessed area relative to the outermost point of the outer surface 131 of the side wall 13 of the housing 1 or relative to the outermost point of the corresponding area corresponding to the weld seam 5 before welding, meaning that the entire outer surface 131 of the corresponding side wall 13 forms a recessed area relative to the outermost point of the corresponding area corresponding to the weld seam 5 before welding.

[0057] For this purpose, as shown in FIG. 4 , according to another exemplary embodiment of the present application, a second side recess structure 312 is formed by recessing the entire outer surface 131 of the side wall 13 of the housing 1 relative to the outermost point of the corresponding area corresponding to the weld seam 5 before welding.

[0058] 3, the outer peripheral edge 22 has an embedded portion 224 embedded in the opening 11, and the embedded portion 224 forms a step with the end surface portion 222. This step is a joint where the embedded portion 224 and the opening peripheral edge 12 overlap from the inside, allowing the cover plate 2 to be positioned relatively stably and prepared for subsequent welding. Naturally, this also increases the strength of the cover plate 2.

[0059] According to another exemplary embodiment of the present application, at least a portion of the embedded portion 224 is welded to the sidewall 13 by the laser 4. Here, two intersecting, particularly perpendicular, interfaces are welded, which can significantly improve the weld strength. In this case, the laser 4 is preferably directed at the intersection of the two interfaces, i.e., the corner of the step in FIG. 3 .

[0060] According to another exemplary embodiment of the present application, as shown in Fig. 3, the first side recess structure 311 is formed by recessing the entire exposed side portion 223 along the side. In this case, the exposed side portion 223 is recessed along the side as a whole. More preferably, the entire exposed side portion 223 is recessed to the same extent so that the side is flat, as shown in Fig. 3.

[0061] Of course, the first side recess structure 311 may be formed by a partial side recess structure 225 formed in the exposed side portion 223. Figure 5 shows such an exemplary embodiment according to the present application. As shown in Figure 5, the partial side recess structure 225 is formed in a step shape on the outermost edge of the exposed side portion 223.

[0062] 6, 7, 8 and 9 show cross-sectional views of a battery housing and cover plate before welding according to different exemplary embodiments of the present application, and provide several possible configurations of partial side setback structures 225.

[0063] 6, 7, 8, and 9, the partial side recess structure 225 can include at least one of a step, a groove, and at least one of a bevel 2251. Those skilled in the art can understand that these structural forms can occur simultaneously or separately.

[0064] As a more specific example, the step and / or groove may be formed on at least one of the two edges of the exposed side portion 223. For example, as shown in Figure 8, the partial side recessed structure 225 is formed in a step shape on the innermost edge of the exposed side portion 223. The bevel 2251 may have any suitable shape.

[0065] For example, as shown in Figures 6 and 7, the bevel 2251 may be configured in a chamfered form. The chamfer may be a beveled chamfer as shown in the figures, or a rounded chamfer. Note that the bevel shown in Figure 6 can also be considered a chamfer, but its two sides are not symmetrical.

[0066] As shown in FIG. 6, in the thickness direction of the cover plate 2, the entire exposed side portion 223 may be configured as a bevel, or as shown in FIG. 7, only a portion of the exposed side portion may be configured as a bevel.

[0067] According to an exemplary embodiment of the present application, the weld seam shape control structure 3 is formed to surround the outer periphery 22 and / or the opening periphery 12. In this case, the cover plate 2 is connected to the housing 1 over the entire periphery by laser welding.

[0068] It should be noted that, as a result of the characteristics of the welding itself, the weld seam is particularly likely to protrude outward from the side at the starting point of the laser arc welding, but is less likely to do so or is less noticeable at other locations. Therefore, according to another exemplary embodiment of the present application, the weld seam shape control structure 3 is formed only at the arc welding starting point. It should be understood that, if the weld seam shape control structure 3 is provided around the entire periphery, welding can be started at any suitable starting point as needed.

[0069] Certainly, the weld seam shape control structure 3 may also be provided at the arc welding end point so that the keyhole porosity at the arc welding end position can be reduced by increasing the laser power.

[0070] Those skilled in the art will appreciate that the weld seam shape control structure 3 can be formed by a circumferentially stepped change. For example, the material subtraction can be greater at the arc welding start point and gradually decrease toward the arc welding end point, thereby achieving a minimum material subtraction at the arc welding end point. Various forms of stepped change are possible.

[0071] In the circumferential direction, the battery may have multiple corners, for example, in the case of a rectangular parallelepiped battery as shown in the figure, there are four corners. When considering the welding process, it is advantageous to use the corners as the starting points for arc welding, and in this case, the weld seam shape control structure 3 is formed only at the peripheral corners of the outer periphery 22 and / or the opening periphery 12.

[0072] In principle, under certain circumstances, the desired purpose can be achieved by forming the weld seam shape control structure 3 only on the side edge of one corner of the cover plate 2.

[0073] According to an exemplary embodiment of the present application, the housing 1 and / or the cover plate 2 are made of an aluminum alloy. As another example, the battery is a lithium-ion battery. In this case, a positive electrode, a negative electrode, a separator, an electrolyte, etc. may be disposed within the housing 1, and a positive electrode terminal and a negative electrode terminal may be disposed on the cover plate 2. These are not the main focus of the present application, and will not be described in further detail here.

[0074] According to an exemplary embodiment of the present application, the housing 1 and / or the cover plate 2 are configured to be formed by stamping. In particular, the aluminum alloy housing 1 and / or the cover plate 2 can be easily formed by stamping.

[0075] In such a situation, it is advantageous that the weld seam shape control structure 3 is configured to be formed simultaneously with the stamping of the housing 1 and / or the cover plate 2, so that it can be completed in a single forming process without the need for extra processing steps. In particular, it is not necessary to change the structural form of the stamping die to the structural form shown in Figures 3 and 4, but only its corresponding dimensions need to be changed.

[0076] According to an exemplary embodiment of the present application, the cover plate 2 is welded to the housing 1 with the opening 11 of the housing 1 facing downward. FIG. 10 schematically illustrates such a welding position using the structural configuration of FIG. 3 as an example. As shown in FIG. 10, the cover plate 2 is supported on a work table 6, and a laser welding head 7 irradiates it from the side to perform welding. In this case, with the help of the recessed area below, the molten material during the welding process tends to flow downward under the action of gravity rather than accumulate sideways. Here, the laser welding head 7 is preferably a fixed welding head.

[0077] In practice, the welding method can be adapted to the specific configuration of the weld seam shape control structure 3. Therefore, the above reverse welding method is merely an example.

[0078] During welding, the laser power can be gradually increased and / or gradually decreased during the welding process according to the specific form of the weld seam shape control structure 3 to further help achieve the aforementioned objectives or reduce or avoid weld craters that are generated especially at the ends of the weld seam during cooling of the molten material during the welding process.

[0079] Additionally, some special forms of weld seam shape control structures 3 can also help position and compress the housing and / or cover plate during the assembly process, thereby reducing the precision requirements of the welding fixture tool.

[0080] According to an exemplary embodiment of the present application, when the side recess structure 31 is formed on the cover plate 2, the recess dimension along the side of the side recess structure 31 may be 5% to 30% of the thickness of the cover plate 2. For example, if the thickness of the cover plate 2 is greater than 1.0 mm, the side recess dimension is 0.05 mm to 0.5 mm, which is very small and can be easily achieved. The thickness of the housing 1 is preferably greater than 0.3 mm. Naturally, the thickness of the housing 1 may be taken into consideration when determining the side recess dimension.

[0081] According to another aspect of the present application, there is provided a laser welding system for a battery according to any of the above exemplary embodiments, the laser welding system including a fixed welding head and a controller, the controller being configured to cause the fixed welding head to start welding from a position having a weld seam shape control structure 3 and weld the cover plate 2 to the housing 1.

[0082] Although particular embodiments of the present application have been described in detail herein, they have been presented for illustrative purposes and should not be construed as limitations on the scope of the present application. Various substitutions, changes, and modifications can be devised without departing from the spirit and scope of the present application.

Claims

1. A battery, a housing (1) having an opening (11); a cover plate (2) covering the opening (11), the cover plate (2) having an end side (21) facing the opening (11) and an outer peripheral edge (22) connected to an opening peripheral edge (12) of the housing (1) surrounding the opening (11); At least a portion of a peripheral section of the outer peripheral edge portion (22) has a first side welding zone (221), and at least a portion of a peripheral section of the opening peripheral edge portion (12) has a second side welding zone (121), at least one of the first side welding zone (221) and the second side welding zone (121) is formed by a weld seam shape control structure (3), and the first side welding zone (221) and the second side welding zone (121) are welded together via a weld seam (5) by a laser (4) irradiated along a side from the outside, and the weld seam shape control structure (3) is configured to control the shape of the weld seam (5) during welding so that the maximum side outer dimension of the weld seam (5) does not exceed the maximum side outer dimension of a region corresponding to the weld seam (5) before welding.

2. The weld seam shape control structure (3) is formed on the outer side surface of the first side welding zone (221) and / or the second side welding zone (121); The battery of claim 1 .

3. The outer peripheral edge portion (22) has an end surface portion (222) that is disposed on the end surface (122) of the opening peripheral edge portion (12) and is consequently welded to the end surface (122), and the weld seam shape control structure (3) is disposed adjacent to the end surface portion (222) and / or the end surface (122). The battery of claim 2.

4. The weld seam shape control structure (3) includes a side recess structure (31) recessed at least partially along a side in the first side welding zone (221) and / or the second side welding zone (121) relative to an outermost point of a corresponding area corresponding to the weld seam (5) before welding. The battery according to any one of claims 1 to 3.

5. The side recess structure (31) comprises a first side recess structure (311) formed on the outer peripheral edge (22) and / or a second side recess structure (312) formed on the opening peripheral edge (12). The battery of claim 4.

6. said outer periphery (22) having an exposed side portion (223) in which said first side recess structure (311) is formed; and / or the second lateral recess structure (312) is formed by recessing the outer surface (131) of the side wall (13) of the housing (1) laterally at least partially relative to the outermost point of the corresponding area corresponding to the weld seam (5) before welding; The battery of claim 5.

7. The outer peripheral edge (22) has a buried portion (224) buried in the opening (11), the buried portion (224) forming a step with the end surface portion (222); and / or said first side recess structure (311) is formed by recessing the entire exposed side portion (223) laterally and / or by a partial side recess structure (225) formed in said exposed side portion (223); and / or the second side recess structure (312) comprises a recessed area extending on the side wall (13) of the housing (1) in a direction away from the end face (122); The battery of claim 6.

8. At least a portion of the embedded portion (224) is welded to the sidewall (13) by the laser (4), and / or the partial side recession structure (225) comprises at least one of a step, a groove, and a bevel (2251); and / or the recessed area extends in a direction away from the end face (122) from the end face (122) to the other end of the side wall (13) opposite the end face (122); The battery of claim 7.

9. said step and / or groove being formed on at least one of the two edges of said exposed side portion (223); and / or said bevel (2251) is configured in a chamfered form; and / or the second side recess structure (312) is formed by recessing the entire outer surface (131) of the side wall (13) of the housing (1) relative to the outermost point of the corresponding area corresponding to the weld seam (5) before welding; The battery of claim 8.

10. The weld seam shape control structure (3) is formed around the outer periphery (22) and / or the opening periphery (12), and / or The weld seam shape control structure (3) is formed through a stepwise change from the arc welding start point to the arc welding end point.

10. The battery of claim 1.

11. The weld seam shape control structure (3) is formed only at the starting point of the arc welding, and / or The weld seam shape control structure (3) is formed only on the outer peripheral edge (22) and / or the peripheral corners of the opening peripheral edge (12). The battery of any one of claims 1 to 10.

12. the battery is configured as a rectangular parallelepiped; and / or the housing (1) and / or the cover plate (2) are made of an aluminum alloy; and / or The battery is a lithium ion battery.

12. The battery of claim 1.

13. the housing (1) and / or the cover plate (2) are adapted to be formed by stamping; and / or The cover plate (2) is welded to the housing (1) with the opening (11) of the housing (1) facing downwards.

13. The battery of any one of claims 1 to 12.

14. The weld seam shape control structure (3) is configured to be formed simultaneously with stamping of the housing (1) and / or the cover plate (2).

14. The battery of claim 13.

15. 15. A laser welding system for a battery according to any one of claims 1 to 14, comprising: a fixed welding head; and a controller configured to cause the fixed welding head to start welding from a position having the weld seam shape control structure (3) and weld the cover plate (2) to the housing (1).

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