Welding auxiliary equipment

Abstract

The present invention discloses a welding auxiliary device, which is applied to the welding of the pole ear and the pole piece of a soft-pack battery cell. The welding auxiliary device includes a first fixing part and a second fixing part, wherein the first fixing part is used to fix the pole piece, and the second fixing part is used to fix the pole ear. The welding auxiliary device also includes a positioning structure, wherein the first fixing part and the second fixing part are assembled together through the positioning structure, and the welding positioning of the pole piece and the pole ear is realized through the positioning structure. The welding auxiliary device can ensure that the pole ear and the pole piece are aligned during welding, so that each battery cell welding point is consistent. The welding auxiliary device is easy to operate, reduces the welding error between the pole piece and the pole ear, can well ensure that the second welding point is not easy to crack, protects the pole piece from being damaged during the welding process, greatly improves the welding quality, and ensures the welding effect.

Description

Technical Field

[0001] The invention relates to the technical field of batteries, in particular to welding auxiliary equipment. Background Art

[0002] Soft-pack lithium battery is another name for polymer battery. Compared with lithium-ion battery, it has many advantages such as small size, light weight, high specific energy, high safety and flexible design.

[0003] Specifically, soft-pack lithium batteries have the following advantages: 1. Good safety performance: soft-pack lithium batteries are structurally packaged with aluminum-plastic film. In the event of a safety hazard, the soft-pack lithium battery will only bulge and crack at most, instead of exploding like steel-shell and aluminum-shell batteries. 2. Light weight: soft-pack lithium batteries are 40% lighter than steel-shell lithium batteries of the same capacity, and 20% lighter than aluminum-shell batteries. 3. Large capacity: soft-pack lithium batteries have a capacity 10-15% higher than steel-shell batteries of the same specifications and sizes, and 5-10% higher than aluminum-shell batteries. 4. Small internal resistance: The internal resistance of soft-pack lithium batteries is smaller than that of lithium batteries. At present, the internal resistance of domestic soft-pack lithium battery cells can be as low as 35mΩ, which greatly reduces the battery's self-consumption. 5. Flexible design: The shape of soft-pack lithium batteries can be customized according to customer needs, and new battery cell models can be developed.

[0004] In the manufacturing process of soft-pack lithium batteries, the tab welding process is an indispensable process in the preparation process of soft-pack batteries. The quality of the tab welding point plays a vital role in the performance of lithium-ion batteries. At present, there are still the following problems in the welding of the tabs of soft-pack batteries: 1) The tabs and the pole pieces are not well aligned during welding, and the tabs are easy to be welded obliquely; 2) Direct welding operation is complicated, with large errors and low efficiency; 3) When the tabs are welded at the second point, the tabs and the pole pieces are not fixed well, which will cause the first welding point to crack; 4) When holding the pole piece for welding, it is easy to damage the pole piece, causing the pole piece to drop. Summary of the invention

[0005] In view of this, one of the objectives of the present invention is to provide a welding auxiliary device that facilitates the welding of the pole tab and the pole piece and can improve the welding effect.

[0006] In order to achieve the above object, on the one hand, the present invention adopts the following technical solution:

[0007] A welding auxiliary device is used for welding the pole ear and the pole piece of a soft-pack battery cell. The welding auxiliary device includes a first fixing part and a second fixing part. The first fixing part is used to fix the pole piece, and the second fixing part is used to fix the pole ear. The welding auxiliary device also includes a positioning structure. The first fixing part and the second fixing part are assembled together through the positioning structure, and the welding positioning of the pole piece and the pole ear is achieved through the positioning structure.

[0008] Preferably, the first fixing part includes a first fixed bottom plate and a first fixed top plate, and the first top plate is buckled with the first bottom plate to form a pole piece fixing space for the pole piece therebetween, and when the pole piece is in a fixed state, at least a portion of the pole piece used for welding to the pole ear is exposed from the edge of the first fixing part.

[0009] Preferably, one of the first fixed bottom plate and the first fixed top plate is provided with a first fixed groove, and the other is provided with a first mating convex surface mating with the first fixed groove, and a pole piece fixing space is formed between the first fixed groove and the first mating convex surface, and when the pole piece is in a fixed state, the pole piece is located in the first fixed groove, and the first mating convex surface cooperates with the first fixed groove to clamp and fix the pole piece.

[0010] Preferably, the first fixed bottom plate and the first fixed top plate are connected via a snap-fit ​​structure and / or fasteners.

[0011] Preferably, the second fixing portion includes a second fixed bottom plate and a second fixed top plate, and the second top plate is buckled with the second bottom plate to form a pole ear fixing space for the pole ear therebetween, and when the pole ear is in a fixed state, at least a portion of the pole ear used for welding to the pole piece is exposed from the edge of the second fixing portion.

[0012] Preferably, one of the second fixed bottom plate and the second fixed top plate is provided with two second fixed grooves, and the other is provided with two second matching convex surfaces matching with the two second fixed grooves, and the pole ear fixing space is formed between the second fixed grooves and the second matching convex surfaces, and when the pole ear is in a fixed state, the two pole ears are respectively located in the two second fixed grooves, and the second matching convex surfaces cooperate with the second fixed grooves to clamp and fix the pole ear.

[0013] Preferably, the second fixed bottom plate and the second fixed top plate are connected via a snap-fit ​​structure and / or fasteners.

[0014] Preferably, the first fixing portion and the second fixing portion are constructed as a rectangular structure, and in the length direction of the first fixing portion, the first fixing groove is located in the middle position of the first fixing portion, and in the length direction of the second fixing portion, the two second fixing grooves are symmetrically arranged with respect to the center plane of the second fixing portion parallel to the width direction.

[0015] Preferably, the positioning structure includes matching positioning holes and positioning pieces, the positioning hole is located on one of the first fixing part and the second fixing part, the positioning piece is connected to the other of the first fixing part and the second fixing part, and the welding positioning of the pole piece and the pole ear is achieved through the matching of the positioning piece and the positioning hole.

[0016] Preferably, an avoidance space for welding the pole piece and the pole lug is provided on the first fixing part and / or the second fixing part, and when the first fixing part and the second fixing part are in an assembled state, the welding part of the pole piece contacts the welding parts of the two pole lugs respectively, and the welding part of the pole piece and the welding part of the pole lug are located in the avoidance space.

[0017] The present invention provides a welding auxiliary equipment, which is provided with a positioning structure, so that the pole ear and the pole piece are aligned during welding, so that each battery cell welding point is consistent. The welding auxiliary equipment is easy to operate and reduces the welding error between the pole piece and the pole ear. Since the pole piece and the pole ear are respectively fixed to the first fixing part and the second fixing part, it can be well ensured that the second welding point is not easy to crack, and the pole piece is protected from being damaged during the welding process, which greatly improves the welding quality and ensures the welding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0019] Figure 1 An exploded schematic diagram showing a first fixing portion and a pole piece of a specific embodiment provided by the present invention;

[0020] Figure 2 The exploded schematic diagram of the second fixing portion and the tab of the specific embodiment provided by the present invention is shown.

[0021] In the figure,

[0022] 1. First fixing part; 11. First fixing bottom plate; 111. First fixing groove; 12. First fixing top plate; 121. First matching convex surface; 2. Second fixing part; 21. Second fixing bottom plate; 211. Second fixing groove; 22. Second fixing top plate; 221. Second matching convex surface; 23. Avoidance space; 3. Positioning structure; 31. Positioning member; 32. Positioning hole; 4. Pole piece; 5. Pole ear. DETAILED DESCRIPTION

[0023] The present invention is described below based on examples, but the present invention is not limited to these examples. In the following detailed description of the present invention, some specific details are described in detail.

[0024] In addition, persons of ordinary skill in the art will appreciate that the drawings provided herein are for illustration purposes and are not necessarily drawn to scale.

[0025] Unless the context clearly requires otherwise, throughout the specification and claims, the words "include", "comprising" and similar words should be interpreted in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to".

[0026] In the description of the present invention, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0027] refer to Figure 1 and 2 As shown, the present invention provides a welding auxiliary equipment, which is applied to the welding of the pole ear 5 and the pole piece 4 of a soft-pack battery cell, and is particularly applied to a soft-pack lithium battery. The welding auxiliary equipment includes a first fixing part 1 and a second fixing part 2, wherein the first fixing part 1 is used to fix the pole piece 4, and the second fixing part 2 is used to fix the pole ear 5. The welding auxiliary equipment also includes a positioning structure 3, wherein the first fixing part 1 and the second fixing part 2 are assembled together through the positioning structure 3, and the welding positioning of the pole piece 4 and the pole ear 5 is achieved through the positioning structure 3. When it is necessary to weld the pole piece 4 and the pole lug 5, first fix the pole piece 4 to the first fixing part 1, fix the two pole lugs 5 to the second fixing part 2, and then assemble the first fixing part 1 and the second fixing part 2 together through the positioning structure 3, and at the same time make the pole piece 4 contact with the welding part of the two pole lugs 5, so as to ensure that the pole lug 5 is aligned with the pole piece 4 during welding, so that each battery cell welding point is consistent, and the welding auxiliary equipment is easy to operate, and reduces the welding error of the pole piece 4 and the pole lug 5. Since the pole piece 4 and the pole lug 5 are respectively fixed to the first fixing part 1 and the second fixing part 2, it can be well ensured that the second welding point is not easy to crack, and the pole piece 4 is protected from being damaged during the welding process, which greatly improves the welding quality and ensures the welding effect. In addition, in order to facilitate the assembly of the first fixing part 1 and the second fixing part 2, it is preferred that the first fixing part 1 and the second fixing part 2 are both rectangular structures, which is more convenient for the alignment of the first fixing part 1 and the second fixing part 2, so that the alignment of the pole piece 4 and the pole lug 5 can be better ensured, and the assembly of the first fixing part 1 and the second fixing part 2 can be facilitated.

[0028] refer to Figure 1As shown, the first fixing part 1 includes a first fixing bottom plate 11 and a first fixing top plate 12, the first top plate is buckled with the first bottom plate, and a fixing space for the pole piece 4 is formed between the two. When the pole piece 4 is in a fixed state, at least a portion of the pole piece 4 used for welding with the pole ear 5 is exposed from the edge of the first fixing part 1 to facilitate the contact between the pole piece 4 and the pole ear 5, thereby facilitating the welding between the pole piece 4 and the pole ear 5. Preferably, the length of the exposed portion of the pole piece 4 is greater than the length of the portion to be welded, so as to provide sufficient space for welding and facilitate the welding operation. For example, a first fixing groove 111 is provided on the first fixing bottom plate 11, and a first matching convex surface 121 matching with the first fixing groove 111 is provided on the first fixing top plate 12. A pole piece fixing space is formed between the first fixing groove 111 and the first matching convex surface 121 for fixing the pole piece 4. When the pole piece 4 is in a fixed state, the pole piece 4 is located in the first fixing groove 111, and the first matching convex surface 121 matches with the first fixing groove 111 to clamp and fix the pole piece 4. Generally, the main body shape of the pole piece 4 is a rectangle, so it is preferred that the pole piece fixing space is also a rectangular space to better adapt to the shape of the pole piece 4 and ensure stable fixation of the pole piece 4. In order to better ensure that the first matching convex surface 121 and the first fixing groove 111 clamp the pole piece 4, it is necessary to ensure that the first fixed bottom plate 11 and the first fixed top plate 12 are fastened together. Preferably, the first fixed bottom plate 11 and the first fixed top plate 12 are connected by a snap-on structure and / or a fastener. The fastener includes a bolt assembly, a screw or a screw, etc. Specifically, the first fixed bottom plate 11 and the first fixed top plate 12 are fastened together by a bolt assembly. Bolt holes are respectively provided at the four corners of the first fixing portion 1 of the rectangular structure. When fixing the pole piece 4, the pole piece 4 is placed in the first fixing groove 111, and the first fixed top plate 12 is placed above the first fixed bottom plate 11. The first matching convex surface 121 is just placed in the first fixing groove 111, and the bolt holes of the first fixed bottom plate 11 and the bolt holes of the first fixed top plate 12 correspond one by one. Then the bolt assembly is screwed on to complete the fixation of the pole piece 4.

[0029] It should be noted that the positions of the above-mentioned first fixing groove 111 and the first matching convex surface 121 can be interchanged, that is, the first fixing groove 111 can be set on the first fixed top plate 12, and correspondingly, the first matching convex surface 121 can be set on the first fixed bottom plate 11, which can also achieve good fixation of the pole piece 4.

[0030] refer to Figure 2As shown, the second fixing part 2 includes a second fixing bottom plate 21 and a second fixing top plate 22. The second top plate and the second bottom plate are buckled to form a fixing space for the pole lug 5 between the two. When the pole lug 5 is in a fixed state, at least the portion of the pole lug 5 used for welding with the pole piece 4 is exposed from the edge of the second fixing part 2 to facilitate the contact between the pole lug 5 and the pole piece 4, thereby facilitating the welding between the pole piece 4 and the pole lug 5. Preferably, the length of the exposed portion of the pole lug 5 is greater than the length of the portion to be welded, so as to provide sufficient space for welding and facilitate the welding operation. For example, two second fixing grooves 211 are provided on the second fixing bottom plate 21, and a second matching convex surface 221 matching with the second fixing groove 211 is provided on the second fixing top plate 22. The pole lug fixing space is formed between the second fixing groove 211 and the second matching convex surface 221 for fixing the pole lug 5. When the pole lug 5 is in a fixed state, the two pole lugs 5 are respectively located in the two second fixing grooves 211, and the second matching convex surface 221 matches with the second fixing groove 211 to clamp and fix the pole lug 5. Generally, the pole lug 5 is an elongated structure, so it is preferred that the second fixing groove 211 is an elongated groove, and the second matching convex surface 221 is an elongated convex surface, that is, the pole lug fixing space is an elongated space, so that the fixation of the pole lug 5 is more reliable and stable. In addition, in order to better fix the pole lug 5, the second matching convex surface 221 needs to be more closely matched with the second fixing groove 211, that is, the second fixing bottom plate 21 needs to be tightly connected and fixed with the second fixing top plate 22, and it is preferred that the second fixing bottom plate 21 and the second fixing top plate 22 are also connected by a snap-fit ​​structure and / or fasteners. Specifically, the second fixing bottom plate 21 and the second fixing top plate 22 are fastened and connected by a bolt assembly, and bolt holes are respectively provided at the four corners of the second fixing portion 2 of the rectangular structure. When fixing the pole lug 5, the two pole lugs 5 of the soft-pack battery cell are respectively placed in the second fixing groove 211 of the second fixing bottom plate 21, and the second fixing top plate 22 is placed above the second fixing bottom plate 21, and the second matching convex surface 221 is just placed in the second fixing groove 211, and the bolt holes of the second fixing bottom plate 21 and the bolt holes of the second fixing top plate 22 correspond one by one, and then the bolt assembly is screwed on to complete the fixation of the pole lug 5.

[0031] It should be noted that the positions of the second fixing groove 211 and the second matching convex surface 221 can be interchanged, that is, the second fixing groove 211 can be set on the second fixed top plate 22, and correspondingly, the second matching convex surface 221 can be set on the second fixed bottom plate 21, which can also achieve good fixation of the pole ear 5.

[0032] refer to Figure 1 and 2As shown, in order to make the fixation of the pole piece 4 and the pole ear 5 more stable, and to facilitate the alignment of the pole piece 4 and the pole ear 5, in the length direction of the first fixing part 1, the first fixing groove 111 is located in the middle position of the first fixing part 1, and correspondingly, in the length direction of the second fixing part 2, the two second fixing grooves 211 are symmetrically arranged about the central plane of the second fixing part 2 parallel to the width direction, so as to ensure that after the first fixing part 1 and the second fixing part 2 are assembled, the welding parts of the pole ear 5 and the pole piece 4 are in contact, so as to ensure the smooth progress of welding. Obviously, in the above scheme, the long sides of the first fixing part 1 and the second fixing part 2 are butt-jointed, so that the assembly of the first fixing part 1 and the second fixing part 2 is more stable. It should be noted that the position of the first fixing groove 111 does not have to be set in the middle position of the length direction of the first fixing part 1, and can also be set at other positions, and the position of the second fixing groove 211 does not have to be set at the position described above, as long as it is ensured that when the first fixing part 1 and the second fixing part 2 are assembled, the welding parts of the pole piece 4 and the pole ear 5 are in contact with each other. Of course, the first fixing part 1 and the second fixing part 2 do not have to be rectangular structures, and can also be other structural shapes. However, the above preferred solution can better ensure the stability of the assembly of the first fixing part 1 and the second fixing part, as well as the good fixation of the pole piece 4 and the pole ear 5. For example, the first fixing part 1 and the second fixing part 2 can be semicircular structures. When the first fixing part 1 and the second fixing part 2 are assembled, the overall structure is a circular structure, that is, the straight edges of the first fixing part 1 and the second fixing part 2 are connected, which can also ensure the good assembly of the first fixing part 1 and the second fixing part 2.

[0033] In addition, it should be noted that due to the provision of the first fixing groove 111 and the second fixing groove 211, the welding auxiliary equipment can adapt to pole pieces 4 and pole tabs 5 of different thicknesses. It is only necessary to place the pole pieces 4 and pole tabs 5 into the first fixing groove 111 and the second fixing groove 211 respectively, and then press and fix them by the first mating convex surface 121 and the second mating convex surface 221 respectively, thereby improving the adaptability of the welding auxiliary equipment.

[0034] Preferably, reference Figure 1 and 2As shown, the positioning structure 3 includes a matching positioning hole 32 and a positioning member 31, the positioning hole 32 is located on one of the first fixing part 1 and the second fixing part 2, and the positioning member 31 is connected to the other of the first fixing part 1 and the second fixing part 2. The first fixing part 1 here includes a first fixing bottom plate 11 and a first fixing top plate 12, and the second fixing includes a second fixing bottom plate 21 and a second fixing top plate 22. For example, when the positioning hole 32 is located at the first fixing bottom plate 11, the positioning member 31 is connected to the second fixing bottom plate 21, and the welding positioning of the pole piece 4 and the pole ear 5 is achieved by the cooperation between the positioning member 31 and the positioning hole 32 to ensure the alignment of the pole piece 4 and the pole ear 5. The positioning connection is achieved by inserting the positioning member 31 into the positioning hole 32, and the reliability of the connection between the first fixing part 1 and the second fixing part 2 can also be improved. It should be noted that one or more positioning structures 3 may be provided. For example, in a specific embodiment, two positioning structures 3 are provided. Two positioning holes 32 are provided on the first fixing part 1. Two positioning members 31 are provided at positions corresponding to the positioning holes 32 on the first fixing part 1. The two positioning members 31 are respectively inserted into the two positioning holes 32 to realize the assembly of the first fixing part 1 and the second fixing part 2. At the same time, the contact between the welding parts of the pole piece 4 and the pole ear 5 is ensured. The provision of two positioning structures 3 can better ensure the reliability of the assembly of the first fixing part 1 and the second fixing part 2, and can also improve the accuracy of the alignment of the pole piece 4 and the pole ear 5, and provide guarantee for the welding quality. Alternatively, a positioning hole 32 and a positioning member 31 may be provided on the first fixing part 1, and then a positioning member 31 and a positioning hole 32 adapted to the above-mentioned positioning hole 32 and positioning member 31 may be provided on the second fixing part 2 to realize cross-positioning and fixing, which can better ensure the fixing effect.

[0035] In addition, refer to Figure 1 and 2 As shown, an avoidance space 23 for welding the pole piece 4 and the pole lug 5 is provided on the first fixing part 1 and / or the second fixing part 2, and when the first fixing part 1 and the second fixing part 2 are in the assembled state, the welding portion of the pole piece 4 contacts the welding portions of the two pole lugs 5 respectively, and the welding portion of the pole piece 4 and the welding portion of the pole lug 5 are located in the avoidance space 23, so as to facilitate the welding operation and to facilitate the observation of whether the pole piece 4 and the pole lug 5 are aligned, thereby further improving the welding efficiency and welding quality.

[0036] refer to Figure 1 and 2As shown, the welding auxiliary equipment proposed in this application perfectly solves the current welding problems of the pole piece 4 and the pole ear 5 of the soft-pack battery cell: 1) The pole ear 5 is not well aligned with the pole piece 4 during welding, and the pole ear 5 is easy to be welded obliquely; 2) The direct welding operation is complicated, with large errors and low efficiency; 3) When the pole ear 5 is welded at the second point, the pole ear 5 and the pole piece 4 are not fixed well, which will cause the first welding point to crack; 4) When holding the pole piece 4 for welding, it is easy to damage the pole piece 4, causing the pole piece 4 to drop. The welding auxiliary equipment has the following beneficial effects: 1) Ensure that the pole ear 5 is aligned with the pole piece 4 during welding, so that each battery cell welding point is consistent; 2) Easy to operate, small error; 3) The second welding point is not easy to crack; 4) Protect the pole piece 4 from being damaged during the welding process; 5) Adapt to pole pieces 4 and pole ears 5 of different thicknesses.

[0037] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

[0038] It should be understood that the above-mentioned embodiments are merely illustrative and not restrictive. Without departing from the basic principles of the present invention, various obvious or equivalent modifications or substitutions that can be made by those skilled in the art to the above-mentioned details will all be included in the scope of the claims of the present invention.

Claims

1. A welding auxiliary equipment, used for welding the pole ear and pole piece of a soft-pack battery cell, characterized in that: The welding auxiliary equipment comprises a first fixing part and a second fixing part, wherein the first fixing part is used to fix the pole piece, and the second fixing part is used to fix the pole lug. The welding auxiliary equipment further comprises a positioning structure, wherein the first fixing part and the second fixing part are assembled together through the positioning structure, and the welding positioning of the pole piece and the pole lug is realized through the positioning structure; The positioning structure comprises a matching positioning hole and a positioning member, wherein the positioning hole is located on one of the first fixing part and the second fixing part, and the positioning member is connected to the other of the first fixing part and the second fixing part, and the welding positioning of the pole piece and the pole ear is realized by the matching of the positioning member and the positioning hole; The positioning structure is provided in plurality.

2. The welding auxiliary equipment according to claim 1, characterized in that: The first fixing part includes a first fixing bottom plate and a first fixing top plate, and the first fixing top plate is buckled with the first fixing bottom plate to form a pole piece fixing space of the pole piece therebetween. When the pole piece is in a fixed state, at least a portion of the pole piece used for welding to the pole ear is exposed from an edge of the first fixing part.

3. The welding auxiliary equipment according to claim 2, characterized in that: One of the first fixed bottom plate and the first fixed top plate is provided with a first fixed groove, and the other is provided with a first matching convex surface matching with the first fixed groove, and the pole piece fixing space is formed between the first fixed groove and the first matching convex surface. When the pole piece is in a fixed state, the pole piece is located in the first fixed groove, and the first matching convex surface matches with the first fixed groove to clamp and fix the pole piece.

4. The welding auxiliary equipment according to claim 3, characterized in that: The first fixed bottom plate is connected to the first fixed top plate via a snap-fit ​​structure and / or fasteners.

5. The welding auxiliary equipment according to claim 3, characterized in that: The second fixing portion includes a second fixing bottom plate and a second fixing top plate, and the second fixing top plate is buckled with the second fixing bottom plate to form a pole ear fixing space for the pole ear therebetween. When the pole ear is in a fixed state, at least a portion of the pole ear used for welding to the pole piece is exposed from an edge of the second fixing portion.

6. The welding auxiliary equipment according to claim 5, characterized in that: One of the second fixed bottom plate and the second fixed top plate is provided with two second fixed grooves, and the other is provided with two second matching convex surfaces matching with the two second fixed grooves, and the pole ear fixing space is formed between the second fixed grooves and the second matching convex surfaces. When the pole ear is in a fixed state, the two pole ears are respectively located in the two second fixed grooves, and the second matching convex surfaces cooperate with the second fixed grooves to clamp and fix the pole ear.

7. The welding auxiliary equipment according to claim 6, characterized in that: The second fixed bottom plate is connected to the second fixed top plate via a snap-fit ​​structure and / or fasteners.

8. The welding auxiliary equipment according to claim 6, characterized in that: The first fixing portion and the second fixing portion are constructed as a rectangular structure. In the length direction of the first fixing portion, the first fixing groove is located in the middle position of the first fixing portion, and in the length direction of the second fixing portion, the two second fixing grooves are symmetrically arranged about the center plane of the second fixing portion parallel to the width direction.

9. The welding auxiliary equipment according to any one of claims 1 to 7, characterized in that: The first fixing part and / or the second fixing part is provided with an avoidance space for welding the pole piece and the pole lug. When the first fixing part and the second fixing part are in an assembled state, the welding part of the pole piece contacts with the welding parts of the two pole lugs respectively, and the welding part of the pole piece and the welding part of the pole lug are located in the avoidance space.

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