Method for manufacturing square and round wound battery cell

Abstract

The present invention discloses a method for manufacturing a square-circle wound battery cell, comprising the following steps: (1) providing a separator strip, a positive electrode strip and a negative electrode strip, wherein the positive electrode strip is provided with a plurality of arc-shaped rounded corner control structures which are separated from each other by a preset distance in the length direction of the positive electrode strip, and the rounded corner control structures are also protruding from the positive electrode strip in the thickness direction of the positive electrode strip; (2) stacking the separator strip, the positive electrode strip and the negative electrode strip together in their thickness direction to form a stacked unit, and the positive electrode strip and the negative electrode strip in the stacked unit are separated by the separator strip; and (3) winding the stacked unit in a winding direction with the rounded corner control structures facing outward, and in the winding process, using all the rounded corner control structures to jointly control and adjust the four corner positions in a preset circle to round corners, so that the stacked unit is wound into a square-circle wound battery cell; thereby effectively reducing the gaps between the square-circle wound battery cells and improving the overall energy volume density.

Description

Technical Field

[0001] The invention relates to the field of batteries, and in particular to a method for manufacturing a square-circle wound battery cell. Background Art

[0002] With the continuous development of economy and the continuous progress of society, people's production and life are provided with extremely rich material consumer goods, and batteries are one of the many material consumer goods.

[0003] At present, the mainstream batteries in the market are divided into cylindrical batteries, square batteries and soft pack batteries. Since the cells of cylindrical batteries are cylindrical in structure, there will be a lot of gaps between the cells when assembling the pack, which affects the overall energy volume density.

[0004] In square batteries, the battery cells are formed by folding, so the manufacturing of square batteries is difficult in the stacking process of the pole pieces. At the folding point of the pole piece, not only the material strength and folding angle must be paid attention to, but also the amount of covering material and other information must be accurately calculated.

[0005] In addition, for soft-pack batteries, due to their low structural strength, they are prone to expansion and leakage.

[0006] Therefore, a method for manufacturing a square-circle wound battery cell is provided to overcome the above-mentioned defects. Summary of the invention

[0007] The object of the present invention is to provide a method for manufacturing a square-circular wound battery cell, so that the prepared square-circular wound battery cell can overcome the defect that a large number of gaps exist between the battery cells when assembling a pack of cylindrical batteries, which affects the overall energy volume density.

[0008] To achieve the above-mentioned purpose, the manufacturing method of the square-circle wound battery cell of the present invention comprises the following steps: (1) providing a diaphragm strip, a positive electrode strip and a negative electrode strip, wherein the positive electrode strip is provided with a plurality of arc-shaped rounded corner control structures which are separated from each other by a preset distance in the length direction of the positive electrode strip, and the rounded corner control structures are also protruding outward from the positive electrode strip in the thickness direction of the positive electrode strip; (2) stacking the diaphragm strip, the positive electrode strip and the negative electrode strip together in their thickness direction to form a stacked unit, and the positive electrode strip and the negative electrode strip in the stacked unit are separated by the diaphragm strip; and (3) winding the stacked unit in a winding direction with the rounded corner control structures facing outward, and in the winding process, using all the rounded corner control structures to jointly control and adjust the four corner positions in a preset circle to be rounded, so that the stacked unit is wound into a square-circle wound battery cell.

[0009] Compared with the prior art, a plurality of rounded corner control structures are provided on the positive electrode strip, which are separated from each other by a preset distance in the length direction of the positive electrode strip and protrude from the positive electrode strip in the thickness direction, and combined with "winding the stacked unit in a winding direction with the rounded corner control structure facing outward", so that when the stacked unit is wound to a preset circle, all the rounded corner control structures jointly control and adjust the four corner positions in the preset circle to be rounded, so that each circle of rounded corners wound on all the rounded corner control structures later is almost consistent with the size of the rounded corner control structure, so that the stacked unit is wound into a square and round wound battery cell, thereby effectively reducing the gap between the square and round wound battery cells when assembling the pack, especially when the bottom area of ​​the battery cell and the number of battery cells are larger, the square and round wound battery cells can save more space when assembling the pack compared with traditional cylindrical batteries, thereby improving the overall energy volume density.

[0010] Preferably, in step (3), the rounded corner control structure of the square-circle wound battery cell is still exposed.

[0011] Preferably, the rounded corner control structure has a first end portion and a second end portion opposite to each other in the width direction of the positive electrode strip, and the first end portion of the rounded corner control structure is flush with the positive electrode strip, or the first end portion of the rounded corner control structure protrudes beyond the positive electrode strip; the second end portion of the rounded corner control structure is flush with the positive electrode strip, or the positive electrode strip protrudes beyond the second end portion of the rounded corner control structure.

[0012] Preferably, in step (1), the fillet control structure is fixed to the positive electrode strip by welding, or the fillet control structure is extended from the corresponding position of the positive electrode strip along the thickness direction of the positive electrode strip.

[0013] Preferably, in step (1), all corners of the fillet control structure are polished into fillets.

[0014] To achieve the above-mentioned purpose, the manufacturing method of the square-circle wound battery cell of the present invention comprises the following steps: (1) providing a separator strip, a positive electrode strip and a negative electrode strip, wherein the negative electrode strip is provided with a plurality of arc-shaped rounded corner control structures which are separated from each other by a preset distance in the length direction of the negative electrode strip, and the rounded corner control structures are also protruding outward from the negative electrode strip in the thickness direction of the negative electrode strip; (2) stacking the separator strip, the positive electrode strip and the negative electrode strip together in their thickness direction to form a stacked unit, and the positive electrode strip and the negative electrode strip in the stacked unit are separated by the separator strip; and (3) winding the stacked unit in a winding direction with the rounded corner control structures facing outward, and in the winding process, using all the rounded corner control structures to jointly control and adjust the four corner positions in a preset circle to be rounded, so that the stacked unit is wound into a square-circle wound battery cell.

[0015] Preferably, in step (3), the rounded corner control structure of the square-circle wound battery cell is still exposed.

[0016] Preferably, the rounded corner control structure has a first end portion and a second end portion opposite to each other in the width direction of the negative electrode strip, and the first end portion of the rounded corner control structure is flush with the negative electrode strip, or the first end portion of the rounded corner control structure protrudes beyond the negative electrode strip; the second end portion of the rounded corner control structure is flush with the negative electrode strip, or the negative electrode strip protrudes beyond the second end portion of the rounded corner control structure.

[0017] Preferably, in step (1), the fillet control structure is fixed to the negative electrode strip by welding, or the fillet control structure is extended from the corresponding position of the negative electrode strip along the thickness direction of the negative electrode strip.

[0018] Preferably, in step (1), all corners of the fillet control structure are polished into fillets. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flow chart of the method for manufacturing the square-circle wound battery cell of the present invention.

[0020] Figure 2 A plan view showing positive electrode strips, negative electrode strips and separator strips stacked together in their thickness directions to form a stacked unit, and the plan view also shows that the positive electrode strips and the negative electrode strips are separated by the separator strips.

[0021] Figure 3 is Figure 2 A plan view showing the winding direction.

[0022] Figure 4 The present invention is a plan view of a square-circle wound battery cell produced by the method for producing the square-circle wound battery cell.

[0023] Figure 5 yes Figure 4 The plan view of the square-circle wound battery cell shown is after hiding the negative electrode strips and separator strips.

[0024] Figure 6 yes Figure 5 A plan view taken along the direction indicated by arrow E.

[0025] Figure 7 The present invention is a plan view of a fillet control structure in a square-circle wound battery cell manufactured by the method for manufacturing a square-circle wound battery cell of the present invention.

[0026] Figure 8 Yes Figure 6 Plan view of the first deformation.

[0027] Fig. 9 Yes Figure 6 Plan view of the second deformation.

[0028] Fig.10 Yes Figure 6 Plan view of the third deformation. DETAILED DESCRIPTION

[0029] Embodiments of the present invention will now be described with reference to the accompanying drawings, wherein like reference numerals represent like elements throughout the several views.

[0030] See also Figures 1 to 5 The manufacturing method of the square-round wound battery cell of the present invention comprises the following steps:

[0031] S001. Provide a separator strip 10, a positive electrode strip 20 and a negative electrode strip 30, wherein the positive electrode strip 20 is provided with four arc-shaped fillet control structures 40 which are separated from each other by a preset distance in the length direction of the positive electrode strip 20 (as indicated by the double arrow A), and the fillet control structure 40 is also protruding from the positive electrode strip 20 in the thickness direction of the positive electrode strip 20 (as indicated by the double arrow C); specifically, Figure 4 and Figure 5 As an example, the fillet control structure 40 in step S001 is fixed to the positive electrode strip 20 by welding. This design facilitates the separate production of the fillet control structure 40 and the positive electrode strip 20, so the production is easier; obviously, according to actual needs, the fillet control structure 40 can also be made by extending from the corresponding position of the positive electrode strip 20 along the thickness direction of the positive electrode strip 20, so that the fillet control structure 40 and the positive electrode strip 20 together form an integrated structure; in addition, the negative electrode strip 30 adopts a full-ear structure, and obviously, it can also be other structures known in the art.

[0032] S002, stacking the separator strip 10, the positive electrode strip 20 and the negative electrode strip 30 together in the thickness direction thereof (referring to the separator strip 10, the positive electrode strip 20 and the negative electrode strip 30) to form a stacking unit 100a, and separating the positive electrode strip 20 and the negative electrode strip 30 in the stacking unit 100a by the separator strip 10, the state is shown in FIG. Figure 2 As shown, the positive electrode strip 20 and the negative electrode strip 30 are prevented from contacting each other and causing a short circuit risk during the process of winding the stacked unit 100a into a square wound battery cell 100; specifically, Figure 2 and Figure 3 As an example, the arrangement order of the separator strip 10, the positive electrode strip 20 and the negative electrode strip 30 in the stacked unit 100a is: separator strip 10-positive electrode strip 20-separator strip 10-negative electrode strip 30. Obviously, according to actual needs, the arrangement order can also be: separator strip 10-negative electrode strip 30-separator strip 10-positive electrode strip 20, or positive electrode strip 20-separator strip 10-negative electrode strip 30-separator strip 10, or negative electrode strip 30-separator strip 10-positive electrode strip 20-separator strip 10, so it is not necessary to use the separator strip 10 as an example. Figure 2 and Figure 3 Limits shown.

[0033] And S003, so that the rounded corner control structure 40 is wound outward (see Figure 3 The stacked unit 100a is wound in the direction indicated by the arrow D in the middle, and during the winding process, all the fillet control structures 40 are used to jointly control and adjust a preset circle (for example, but not limited to Figure 4 and Figure 5 The four corners of the sixth circle shown in FIG. 1 are rounded, so that Figure 2 and Figure 3 The stacked unit 100 is shown wound into Figure 4 The square-circle wound battery cell 100 shown; specifically, the rounded corner control structure 40 of the square-circle wound battery cell 100 in step S003 is also exposed to the outside, so that the rounded corner control structure 40 of the square-circle wound battery cell 100 also has a current collecting function, and the way how the rounded corner control structure 40 is exposed to the outside will be described below. More specifically, as follows:

[0034] like Figure 7 In step S001, all corners of the fillet control structure 40 are polished into fillets 43 to prevent the fillet control structure 40 from piercing the negative electrode strip 30, the positive electrode strip 20 and the separator strip 10. In addition, the projection profile of the fillet control structure 40 in the width direction of the positive electrode strip 20 includes an inner arc line 46, an outer arc line 45 and an inclined line 47 connecting the ends of the inner arc line 46 and the outer arc line 46. This design makes the arc lengths of the inner arc line 46 and the outer arc line 45 of the fillet control structure 40 as equal as possible, thereby ensuring the reliability of the combination of the fillet control structure 40 and the positive electrode strip 20 while reducing the length of the outer arc line 45 of the fillet control structure 40. Figure 7 shown.

[0035] like Figure 4 and Figure 5 In the square-circle wound battery cell 100, two adjacent rounded corner control structures 40 in the winding direction are each provided with inclined portions 44 facing each other and arranged with an enlarged spacing from each other radially outwardly of the square-circle wound battery cell 100, and the projection of the inclined portions 44 in the width direction of the positive electrode strip 20 forms an inclined line 47.

[0036] like Figure 6 As shown, the fillet control structure 40 has a first end portion 41 and a second end portion 42 opposite to each other in the width direction of the positive electrode strip 20 (as indicated by the double arrow B). The first end portion 41 of the fillet control structure 40 protrudes outward from the positive electrode strip 20, so that the fillet control structure 40 of the square-round wound battery cell 100 is exposed to the outside. The second end portion 42 of the fillet control structure 40 is flush with the positive electrode strip 20.

[0037] See also Figure 8, it is Figure 6 The first deformation is performed. Figure 8 In the embodiment, the first end portion 41 of the fillet control structure 40 protrudes outward from the positive electrode strip 20 and Figure 6 The difference is: Figure 8 The positive electrode strip 20 in the embodiment of the present invention protrudes outward from the second end portion 42 of the rounded corner control structure 40, and Figure 6 In the middle, the second end 42 of the rounded corner control structure 40 protrudes outward from the positive electrode strip 20 .

[0038] Apart from this difference, Figure 6 The same, so no longer repeat here.

[0039] See also Fig. 9 , it is Figure 6 Perform the second deformation. Fig. 9 In the embodiment, the first end portion 41 and the second end portion 42 of the fillet control structure 40 are flush with the positive electrode strip 20; Figure 6 In the embodiment, the first end portion 41 of the rounded corner control structure 40 protrudes outward from the positive electrode strip 20 , and the second end portion 42 of the rounded corner control structure 40 is flush with the positive electrode strip 20 .

[0040] In addition to the above differences, other Figure 6 The same, so no longer repeat here.

[0041] See also Fig.10 , it is Figure 6 The third deformation is carried out. Fig.10 In the embodiment, the positive electrode strips 20 are protruded from the first end portion 41 and the second end portion 42 of the fillet control structure 40; Figure 6 In the embodiment, the first end portion 41 of the rounded corner control structure 40 protrudes outward from the positive electrode strip 20 , and the second end portion 42 of the rounded corner control structure 40 is flush with the positive electrode strip 20 .

[0042] In addition to the above differences, other Figure 6 The same, so no longer repeat here.

[0043] Compared with the prior art, the positive electrode strip 20 is provided with a plurality of fillet control structures 40 which are separated from each other by a preset distance in the length direction of the positive electrode strip 20 (which is determined according to the position of the preset circle and is a value well known in the art) and protrude outward from the positive electrode strip 20 in the thickness direction, and combined with "winding the stacked unit 100a in a winding direction such that the fillet control structure 40 faces outward", so that the stacked unit 100a is wound to a preset circle (for example, but not limited to Figure 4 and Figure 5When the sixth circle is shown, all the corner fillet control structures 40 jointly control and adjust the four corner positions in the preset circle to be filleted, so that each circle of fillet wound on all the corner fillet control structures 40 later is almost consistent with the size of the corner fillet control structure 40, so that the stacked unit 100a is wound into a square-circular wound battery cell 100, thereby effectively reducing the gap between the square-circular wound battery cells 100 when assembling the pack, especially when the battery cell bottom area and the number of battery cells are larger, the square-circular wound battery cell 100 can save more space when assembling the pack compared to the traditional cylindrical battery cell, thereby improving the overall energy volume density.

[0044] It should be noted that the aforementioned "winding direction so that the rounded corner control structure 40 faces outward" means that the rounded corner control structure 40 is convex toward the outside of the circle where it is located, rather than convex toward the inside of the circle. Figure 5 In the sixth circle, the fillet control structure 40 is convex outside the circle, rather than convex inside the circle. In addition, although the accompanying drawings illustrate that the fillet control structure 40 is provided on the positive electrode strip 20, it is obvious that in other embodiments, the fillet control structure 40 can also be provided by the negative electrode strip 30. That is to say, in other embodiments, the implementation method in which the fillet control structure 40 is provided by the negative electrode strip 30 can be obtained by regarding the number 20 in the accompanying drawings as the negative electrode strip and the number 30 in the accompanying drawings as the positive electrode strip. In addition, the lengths of the separator strip 10, the positive electrode strip 20 and the negative electrode strip 30 are determined by the number of circles of the square and round wound battery cell 100 to be produced, and its value is well known in the art, so it will not be repeated here. Finally, when the corner fillet control structure 40 is only used to adjust the shape of the circularly wound battery cell 100, the corner fillet control structure 40 can be a conductive or non-conductive structure. Since the corner fillet control structure 40 is used to adjust the shape of the circularly wound battery cell 100, the hardness of the corner fillet control structure 40 needs to be greater than the hardness of the diaphragm strip 10, the positive electrode strip 20 and the negative electrode strip 30, so as to satisfy the function of the corner fillet control structure 40 to support and control the fillet of the coil layer wound outside the corner fillet control structure 40 during the winding process of the stacked unit 100a.

[0045] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A method for manufacturing a square-round wound battery cell, characterized in that: Includes steps: (1) providing a separator strip, a positive electrode strip and a negative electrode strip, wherein the positive electrode strip is provided with a plurality of arc-shaped fillet control structures which are separated from each other by a preset distance in the length direction of the positive electrode strip, and the fillet control structures are also convex from the positive electrode strip in the thickness direction of the positive electrode strip; (2) stacking the separator strip, the positive electrode strip and the negative electrode strip together in their thickness direction to form a stacked unit, and separating the positive electrode strip and the negative electrode strip in the stacked unit by the separator strip; and (3) The stacked unit is wound in a winding direction with the rounded corner control structure facing outward, and in the winding process, all the rounded corner control structures are used to jointly control and adjust the four corner positions in a preset circle to be rounded, so that the stacked unit is wound into a square-circle wound battery cell; The projection profile of the fillet control structure in the width direction of the positive electrode strip includes an inner arc line, an outer arc line, and an inclined line connecting the ends of the inner arc line and the outer arc line.

2. The method for manufacturing a square-round wound battery cell according to claim 1, characterized in that: In step (3), the rounded corner control structure of the square-circle wound battery cell is still exposed.

3. The method for manufacturing a square-round wound battery cell according to claim 1, characterized in that: The rounded corner control structure has a first end portion and a second end portion opposite to each other in the width direction of the positive electrode strip. The first end portion of the rounded corner control structure is flush with the positive electrode strip, or the first end portion of the rounded corner control structure protrudes beyond the positive electrode strip; the second end portion of the rounded corner control structure is flush with the positive electrode strip, or the positive electrode strip protrudes beyond the second end portion of the rounded corner control structure.

4. The method for manufacturing a square-round wound battery cell according to claim 1, characterized in that: In step (1), the fillet control structure is fixed to the positive electrode strip by welding, or the fillet control structure is extended from the corresponding position of the positive electrode strip along the thickness direction of the positive electrode strip.

5. The method for manufacturing a square-round wound battery cell according to claim 1, characterized in that: In step (1), all corners of the fillet control structure are ground into fillets.

6. A method for manufacturing a square-round wound battery cell, characterized in that: Includes steps: (1) providing a separator strip, a positive electrode strip and a negative electrode strip, wherein the negative electrode strip is provided with a plurality of arc-shaped fillet control structures which are spaced apart from each other by a preset distance in the length direction of the negative electrode strip, and the fillet control structures are also convex from the negative electrode strip in the thickness direction of the negative electrode strip; (2) stacking the separator strip, the positive electrode strip and the negative electrode strip together in their thickness direction to form a stacked unit, and separating the positive electrode strip and the negative electrode strip in the stacked unit by the separator strip; and (3) The stacked unit is wound in a winding direction with the rounded corner control structure facing outward, and in the winding process, all the rounded corner control structures are used to jointly control and adjust the four corner positions in a preset circle to be rounded, so that the stacked unit is wound into a square-circle wound battery cell; The projection contour of the fillet control structure in the width direction of the negative electrode strip includes an inner arc line, an outer arc line, and an inclined line connecting the ends of the inner arc line and the outer arc line.

7. The method for manufacturing a square-round wound battery cell according to claim 6, characterized in that: In step (3), the rounded corner control structure of the square-circle wound battery cell is still exposed.

8. The method for manufacturing a square-round wound battery cell according to claim 6, characterized in that: The rounded corner control structure has a first end portion and a second end portion opposite to each other in the width direction of the negative electrode strip. The first end portion of the rounded corner control structure is flush with the negative electrode strip, or the first end portion of the rounded corner control structure protrudes beyond the negative electrode strip; the second end portion of the rounded corner control structure is flush with the negative electrode strip, or the negative electrode strip protrudes beyond the second end portion of the rounded corner control structure.

9. The method for manufacturing a square-round wound battery cell according to claim 6, characterized in that: In step (1), the fillet control structure is fixed to the negative electrode strip by welding, or the fillet control structure is extended from the corresponding position of the negative electrode strip along the thickness direction of the negative electrode strip.

10. The method for manufacturing a square-round wound battery cell according to claim 6, characterized in that: In step (1), all corners of the fillet control structure are ground into fillets.

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