Winding cell and cylindrical battery

Abstract

The utility model discloses a kind of winding electric core and cylindrical battery, the winding electric core in it includes positive sheet, diaphragm, negative sheet sequentially laminated;Positive sheet includes first coating area and first tab area, and negative sheet includes second coating area and second tab area, in the axial direction of winding electric core, first tab area and second tab area are respectively located at both ends of winding electric core;Wherein, two first corners are formed in the both ends of first tab area by folding, two second corners are formed in the both ends of second tab area by folding. By setting two first corners, two second corners, respectively adhere to first tab area and second tab area, when smoothing, first corner and second corner can adhere to the tab area where it is, can avoid the tip of the both ends of first tab area or second tab area to insert reversely and contact with the tab sheet of other polarity and short circuit, or not easy to turn outwards, avoid with shell contact and corrode shell, improve stability.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion battery technology, and in particular to a wound cell and a cylindrical battery. Background Technology

[0002] During the manufacturing of cylindrical batteries, the aluminum foil substrates of the anode and cathode plates are coated and rolled to form a uniform active material coating. At the same time, uncoated areas are left at specific locations on the electrodes; these exposed aluminum foil areas form the tabs integrated with the electrodes. When the anode, separator, and cathode plates are stacked and wound to form a wound cell, the tabs need to be flattened or smoothed to facilitate subsequent welding and connection with other structures.

[0003] However, during the flattening process of the tabs, the beginning and end of the tabs are prone to being inserted backwards into the winding cell, causing a short circuit due to overlap, or they are prone to flipping outwards and overlapping with the casing during the subsequent casing insertion process of the winding cell, thus causing casing corrosion and affecting the reliability of the winding cell after it is formed into a battery cell. Utility Model Content

[0004] The main purpose of this invention is to propose a wound battery cell that solves the technical problem in the prior art where the tabs of the electrode sheets are easily inserted upside down or flipped outwards after being smoothed out after winding, thus causing a short circuit in the wound battery cell.

[0005] To achieve the above objectives, in a first aspect, this utility model proposes a wound battery cell, comprising a positive electrode sheet, a separator, and a negative electrode sheet stacked sequentially. The positive electrode includes a first coating area and a first tab area, and the negative electrode includes a second coating area and a second tab area. In the axial direction of the wound cell, the first tab area and the second tab area are located at both ends of the wound cell, respectively. The first electrode area is folded in half at both ends to form two first angles with opposite folding directions, and the second electrode area is folded in half at both ends to form two second angles with opposite folding directions.

[0006] In some embodiments, the distance between the endpoint of any of the first bends and the inner edge of the first tab region is greater than or equal to 0.5 mm.

[0007] In some embodiments, the side of any first fold away from the other first fold forms a first angle with the crease, and the distance between the vertex of the first angle and the inner edge of the first tab region is greater than or equal to 1.5 mm and less than or equal to 2.5 mm.

[0008] In some embodiments, the side of any first fold angle closest to the other first fold angle forms a second angle with the crease, the first angle being greater than or equal to 60° and less than or equal to 70°, the second angle being greater than or equal to 20° and less than or equal to 30°, and the sum of the first angle and the second angle being equal to 90°.

[0009] In some embodiments, the distance between the endpoint of any of the second bends and the inner edge of the second tab region is greater than or equal to 0.5 mm.

[0010] In some embodiments, a third angle is formed between the side of any second fold angle away from the other second fold angle and the crease, wherein the distance between the vertex of the third angle and the inner edge of the second tab area is greater than or equal to 1.5 mm and less than or equal to 2.5 mm.

[0011] In some embodiments, a fourth angle is formed between the side of any second fold angle close to the other second fold angle and the crease, wherein the third angle is greater than or equal to 60° and less than or equal to 70°, the fourth angle is greater than or equal to 20° and less than or equal to 30°, and the sum of the third angle and the fourth angle is equal to 90°.

[0012] In some embodiments, the projected area of ​​any of the first bends along the length of the positive electrode is less than or equal to 10 mm. 2 ; and / or, The projected area of ​​any of the second bends along the length of the negative electrode is less than or equal to 10 mm. 2 .

[0013] In some embodiments, a first bend and a second bend located on the inner ring of the wound cell are attached to the inner side of the subsequent winding ring facing the central axis, and another first bend and a second bend located on the outer ring of the wound cell are attached to the outer side of the previous winding ring away from the central axis.

[0014] Secondly, this utility model also proposes a cylindrical battery, including a casing and a wound cell as described above, wherein the wound cell is disposed inside the casing.

[0015] This invention folds the two ends of the first tab area of ​​the positive electrode sheet to form two first angles, and folds the two ends of the second tab area of ​​the negative electrode sheet to form two second angles. The first and second angles are plastically deformed and attached to the first and second tab areas respectively. During the subsequent winding process of the battery cell, when the first and second tab areas are smoothed, the first and second angles can remain attached to their respective tab areas under the action of external force. This can prevent the tips of the first or second tab areas of the positive or negative electrode sheet from being inserted upside down and coming into contact with other polarity electrodes, thus avoiding short circuits. At the same time, the attached state is not easy to flip outward, avoiding contact with the battery casing during subsequent casing insertion, thereby avoiding corrosion of the casing and improving stability and safety. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of an embodiment of the wound battery cell of this utility model; Figure 2 This is a schematic diagram of the structure of an embodiment of the positive electrode sheet of this utility model; Figure 3 This is a schematic diagram of the structure of an embodiment of the negative electrode sheet of this utility model; Figure 4 This is a schematic diagram of the structure of an embodiment of the wound battery cell of this utility model.

[0017] Explanation of icon numbers: . Detailed Implementation

[0018] The solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0019] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0020] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.

[0021] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0022] Please refer to Figures 1 to 3 This utility model proposes a wound battery cell 400, which includes a positive electrode 100, a separator 300 and a negative electrode 200 stacked in sequence. The positive electrode 100 includes a first coating area 110 and a first tab area 120, and the negative electrode 200 includes a second coating area 210 and a second tab area 220. In the axial direction of the wound cell 400, the first tab area 120 and the second tab area 220 are located at both ends of the wound cell 400, respectively. The first electrode region 120 is folded in half at both ends to form two first angles 121 with opposite folding directions, and the second electrode region 220 is folded in half at both ends to form two second angles 221 with opposite folding directions.

[0023] Please refer to Figure 2 and Figure 3 After the aluminum foil substrates of the positive electrode 100 and the negative electrode 200 are coated and rolled to form a uniform active material coating, a first coating area 110 and a second coating area 210 are formed. Simultaneously, uncoated areas are retained at specific locations on the positive electrode 100 and the negative electrode 200 to form a first tab area 120 and a second tab area 220. The exposed aluminum foil in the first tab area 120 and the second tab area 220 forms the tabs integrated with the electrode. Since the tabs in the first tab area 120 and the second tab area 220 originate from the same metal substrate as the electrode, there is no welding interface between them. This naturally avoids defects such as incomplete welding, over-welding, and burn-through that may occur in traditional welding processes. It also eliminates the risk of thermal damage to the active material of the positive electrode 100 and the negative electrode 200 caused by the high temperature during the welding process, thus improving the structural stability of the positive electrode 100 and the negative electrode 200.

[0024] After the prepared positive electrode 100 and negative electrode 200 are stacked in sequence as positive electrode 100-separator 300-negative electrode 200 to form a wound cell 400, the first tab region 120 and the second tab region 220 are located at the two ends of the wound cell 400, which can avoid direct contact at the same height to form a short circuit circuit, which would cause the wound cell 400 to overheat and explode, thus improving the safety and stability of the wound cell 400.

[0025] Typically, when manufacturing the wound cell 400, smoothing it while winding can reduce the risk of bending, deformation, or wrinkling of the first tab area 120 and the second tab area 220 during the winding process, so that they can be welded to other structures later.

[0026] However, during the flattening process of the first tab area 120 and the second tab area 220, the beginning and end positions of the first tab area 120 and the second tab area 220 are prone to being inserted backwards into the winding cell 400, causing a short circuit due to overlap, or they are prone to flipping outwards and overlapping with the casing during the subsequent casing insertion process of the winding cell 400, thereby causing casing corrosion and affecting the reliability of the winding cell 400 after forming a cylindrical battery cell.

[0027] Therefore, please refer to Figure 2 Two first folds 121 are provided in the first tab region 120 of the positive electrode 100, and two second folds 221 are provided in the second tab region 220 of the negative electrode 200. The first folds 121 are located at both ends of the first tab region 120, i.e., at the beginning and end positions along the length of the positive electrode 100. The two ends of the first tab region 120 are folded inwards, for example, one end is folded inwards and the other end is folded outwards. The first folds 121 can be made using a folding device. The second folds 221 are made in the same way and will not be described in detail here.

[0028] This invention folds the two ends of the first tab region 120 of the positive electrode 100 to form two first angles 121, and folds the two ends of the second tab region 220 of the negative electrode 200 to form two second angles 221. The first angles 121 and the second angles 221 are plastically deformed and attached to the first tab region 120 and the second tab region 220 respectively. In the subsequent manufacturing process of the wound cell 400, when the first tab region 120 and the second tab region 220 are smoothed, the first angles 121 and the second angles 221 can continue to be attached to their respective tab regions under the action of external force. This can prevent the tips of the first tab region 120 or the second tab region 220 of the positive electrode 100 or the negative electrode 200 from being inserted upside down and coming into contact with other polarity electrodes, thus preventing short circuits. At the same time, the attached state is not easy to flip outward, avoiding contact with the battery casing during subsequent casing insertion, thereby avoiding corrosion of the casing and improving stability and safety.

[0029] In some embodiments, the distance between the endpoint of any first bend 121 and the inner edge of the first tab region 120 is greater than or equal to 0.5 mm.

[0030] The first fold 121 is triangular in shape, and the distance between its endpoint furthest from the fold and the inner edge of the first tab region 120 can be 0.5mm, 0.6mm, or 0.7mm, etc. For example, a distance of 0.5mm can prevent the first fold 121 from contacting the negative electrode 200 of the other polarity during the winding of the positive electrode 100, thus avoiding a short circuit. Simultaneously, it also prevents the first fold 121 from being too close to the first coating region 110, thus preventing it from continuing to move downwards and contacting the first coating region 110 after being smoothed out, thereby avoiding an increase in internal resistance. Of course, the above is only exemplary; the specific distance can be determined according to actual needs, and this utility model does not impose any limitations here.

[0031] In some embodiments, the side of any first fold angle 121 away from the other first fold angle 121 forms a first angle with the crease. The distance between the vertex of the first angle and the inner edge of the first tab area 120 is greater than or equal to 1.5 mm and less than or equal to 2.5 mm. The distance between the vertex of the first angle and the inner edge of the first tab area 120 can be selected within the range of 1.5 mm to 2.5 mm, depending on the actual situation; for example, it can be 1.5 mm, 2.0 mm, or 2.5 mm. By adopting an appropriate distance, on the one hand, it can avoid the first fold angle 121 being too small, which would still cause outward flipping during smoothing; on the other hand, it can prevent the first fold angle 121 from being too large, which would contact the first coating area 110 during smoothing and increase the internal resistance of the wound cell 400.

[0032] In some embodiments, the side of any first fold angle 121 closest to another first fold angle 121 forms a second angle with the crease. The first angle is greater than or equal to 20° and less than or equal to 30°, and the second angle is greater than or equal to 60° and less than or equal to 70°, with the sum of the first and second angles equal to 90°. The angle of the first angle can be selected within the range of 20°-30°, for example, 20°, 25°, or 30°; the angle of the second angle can be selected within the range of 60°-70°, for example, 60°, 65°, or 70°. It should be noted that the sum of the two angles is 90°; that is, when the first angle is 30°, the second angle is set to 60°. By reasonably setting the sizes of the first and second angles, the size of the first fold angle 121 can also be adjusted to avoid it being too large or too small and affecting the wound cell 400 during smoothing.

[0033] In some embodiments, the distance between the endpoint of any second bend 221 and the inner edge of the second tab region 220 is greater than or equal to 0.5 mm.

[0034] The second fold angle 221 is also triangular in shape, and the distance between its endpoint furthest from the fold and the inner edge of the second tab area 220 can be 0.5mm, 0.6mm, or 0.7mm, etc. For example, a distance of 0.5mm can prevent the second fold angle 221 from contacting the positive electrode 100 of the other polarity during the winding of the negative electrode 200, thus preventing a short circuit. Simultaneously, it also prevents the second fold angle 221 from being too close to the second coating area 210, thus avoiding further downward displacement and contact with the second coating area 210 after smoothing, thereby preventing an increase in internal resistance. Of course, the above is only an example; the specific distance can be determined according to actual needs, and this utility model does not impose any limitations here.

[0035] In some embodiments, the side of any second fold angle 221 away from the other second fold angle 221 forms a third angle with the crease. The distance between the vertex of the third angle and the inner edge of the second tab area 220 is greater than or equal to 1.5 mm and less than or equal to 2.5 mm. The distance between the vertex of the third angle and the inner edge of the second tab area 220 can be selected within the range of 1.5 mm to 2.5 mm, depending on the actual situation; for example, it can be 1.5 mm, 2.0 mm, or 2.5 mm. By adopting an appropriate distance, on the one hand, it can avoid the second fold angle 221 being too small, which would still cause outward flipping during smoothing; on the other hand, it can prevent the second fold angle 221 from contacting the second coating area 210 during smoothing, thus avoiding an increase in the internal resistance of the wound cell 400.

[0036] In some embodiments, the side of any second fold angle 221 closest to another second fold angle 221 forms a fourth angle with the crease. The third angle is greater than or equal to 20° and less than or equal to 30°, the fourth angle is greater than or equal to 60° and less than or equal to 70°, and the sum of the third and fourth angles is equal to 90°. The angle of the third angle can be selected within the range of 20°-30°, for example, 20°, 25°, or 30°; the angle of the fourth angle can be selected within the range of 60°-70°, for example, 60°, 65°, or 70°. It should be noted that the sum of the two angles is 90°; that is, when the third angle is 25°, the fourth angle is set to 65°. By reasonably setting the sizes of the third and fourth angles, the size of the second fold angle 221 can also be adjusted to avoid it being too large or too small and affecting the wound cell 400 during smoothing.

[0037] In some embodiments, the projected area of ​​any first bend angle 121 along the length of the positive electrode 100 is less than or equal to 10 mm². 2 In other words, the area of ​​the first fold angle 121 can be 10 mm². 2 9mm 2 Or 8mm 2The specifics can be determined according to actual needs. By setting the size of the first fold angle 121, it is possible to avoid its excessive size affecting the wound cell 400 during smoothing.

[0038] In some embodiments, the projected area of ​​any second bend 221 along the length of the negative electrode 200 is less than or equal to 10 mm. 2 In other words, the area of ​​the second fold angle 221 can be 10 mm². 2 9mm 2 Or 8mm 2 The specifics can be determined according to actual needs. By setting the size of the second fold angle 221, it is possible to avoid its excessive size affecting the wound cell 400 during smoothing.

[0039] Please refer to Figure 4 A first bend 121 and a second bend 221 located on the inner ring of the wound cell 400 are attached to the inner side of the next winding ring facing the central axis, and another first bend 121 and another second bend 221 located on the outer ring of the wound cell 400 are attached to the outer side of the previous winding ring away from the central axis.

[0040] When the positive electrode 100, separator 300, negative electrode 200, and separator 300 are stacked and wound, the first bend 121 and the second bend 221 of the inner ring are located on the outer side of the winding ring away from the central axis, and can be abutted by the inner side of the next winding ring facing the central axis, so that the first bend 121 and the second bend 221 are both firmly in the inner ring; while the first bend 121 and the second bend 221 of the outer ring are located on the inner side of the winding ring facing the central axis, and can be abutted by the outer side of the previous winding ring away from the central axis, so that the first bend 121 and the second bend 221 are firmly in the outer ring, and are not prone to flipping outward and contacting the subsequent shell, thus avoiding shell corrosion and improving stability.

[0041] Secondly, this utility model also proposes a cylindrical battery, including a casing and the above-mentioned wound cell 400, wherein the wound cell 400 is disposed inside the casing.

[0042] It should be noted that since the wound cell 400 of the cylindrical battery adopts all the technical solutions of all the above embodiments, the cylindrical battery of this utility model also has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0043] The above are only some or preferred embodiments of this utility model. Neither the text nor the drawings should limit the scope of protection of this utility model. All equivalent structural transformations made using the contents of this utility model specification and drawings under the overall concept of this utility model, or direct / indirect applications in other related technical fields, are included within the scope of protection of this utility model.

Claims

1. A wound battery cell, characterized in that, It includes a positive electrode, a separator, and a negative electrode stacked in sequence; The positive electrode includes a first coating area and a first tab area, and the negative electrode includes a second coating area and a second tab area. In the axial direction of the wound cell, the first tab area and the second tab area are located at both ends of the wound cell, respectively. The first electrode area has two first angles formed by folding its two ends in opposite directions, and the second electrode area has two second angles formed by folding its two ends in opposite directions.

2. The wound battery cell according to claim 1, characterized in that, The distance between the endpoint of any of the first bends and the inner edge of the first tab region is greater than or equal to 0.5 mm.

3. The wound battery cell according to claim 1, characterized in that, The side of any first fold away from the other first fold forms a first angle with the crease, and the distance between the vertex of the first angle and the inner edge of the first tab area is greater than or equal to 1.5 mm and less than or equal to 2.5 mm.

4. The wound battery cell according to claim 3, characterized in that, The side of any first fold angle closest to the other first fold angle forms a second angle with the crease, wherein the first angle is greater than or equal to 20° and less than or equal to 30°, the second angle is greater than or equal to 60° and less than or equal to 70°, and the sum of the first angle and the second angle is equal to 90°.

5. The wound battery cell according to claim 1, characterized in that, The distance between the endpoint of any of the second bends and the inner edge of the second tab region is greater than or equal to 0.5 mm.

6. The wound battery cell according to claim 1, characterized in that, The side of any second fold away from the other second fold forms a third angle with the crease, and the distance between the vertex of the third angle and the inner edge of the second tab area is greater than or equal to 1.5 mm and less than or equal to 2.5 mm.

7. The wound battery cell according to claim 6, characterized in that, The side of any second fold angle closest to the other second fold angle forms a fourth angle with the crease, wherein the third angle is greater than or equal to 20° and less than or equal to 30°, the fourth angle is greater than or equal to 60° and less than or equal to 70°, and the sum of the third angle and the fourth angle is equal to 90°.

8. The wound battery cell according to claim 1, characterized in that, The projected area of ​​any of the first bends along the length of the positive electrode is less than or equal to 10 mm. 2 ; and / or, The projected area of ​​any of the second bends along the length of the negative electrode is less than or equal to 10 mm. 2 .

9. The wound battery cell according to claim 1, characterized in that, A first bend and a second bend located on the inner ring of the wound cell are attached to the inner side of the next winding ring facing the central axis, and another first bend and a second bend located on the outer ring of the wound cell are attached to the outer side of the previous winding ring away from the central axis.

10. A cylindrical battery, characterized in that, It includes a housing and a wound battery cell as described in any one of claims 1 to 9, wherein the wound battery cell is disposed within the housing.

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