Winding battery cell and battery

Abstract

The invention discloses a winding battery cell and a battery, the winding battery cell comprises a positive plate, a negative plate and a diaphragm, the diaphragm is arranged between the positive plate and the negative plate, and the positive plate, the negative plate and the diaphragm are laminated and form the winding battery cell along the winding direction; the winding cell is provided with a straight area and arc areas arranged at the two ends of the extension direction of the straight area, the positive plate is provided with positive arc sections located in the arc areas, and the negative plate is provided with negative arc sections located in the arc areas; and in the same arc area, the positive notches and the negative notches located on the same side are alternately overlapped so as to form chamfers at the corners of the winding battery cell, the sizes of the positive notches are gradually increased from the inner ring to the outer ring, and the sizes of the negative notches are gradually increased from the inner ring to the outer ring. According to the winding battery cell provided by the embodiment of the invention, the problem that the soft package shell is easy to break corners after the winding battery cell forms the soft package battery can be avoided.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a wound battery cell and battery. Background Technology

[0002] As the demand for extended battery life in the end-user market continues to increase, cell design is gradually moving towards maximizing space utilization.

[0003] Within a fixed volume space, the effective capacity ratio of the core is constantly increasing, while packaging materials are also trending towards thinner and lighter designs. For example, the length, width, and height of the core are designed to be extremely thin, and the thickness of the aluminum-plastic film used for the soft-pack battery casing is continuously reduced. At the same time, since the aluminum-plastic film needs to be formed through a stamping process, the corners formed are structurally weak areas. During battery use, the expansion of the cell will exert continuous stress on the corners of the soft-pack casing, which can easily cause corner breakage.

[0004] Therefore, the wound cells in the related technology are prone to corner breakage when forming the soft-pack casing of the soft-pack battery. Summary of the Invention

[0005] This invention provides a wound battery cell to solve the problem in related technologies where wound battery cells are prone to corner breakage when forming the soft-pack casing of a soft-pack battery.

[0006] The wound battery cell of the present invention includes a positive electrode sheet, a negative electrode sheet, and a separator. The separator is disposed between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the negative electrode sheet, and the separator are stacked and arranged along the winding direction to form the wound battery cell. The wound battery cell has a flat region and arc regions disposed at both ends of the extension direction of the flat region. The positive electrode sheet has a positive arc segment located in the arc region, and the negative electrode sheet has a negative arc segment located in the arc region. In the same arc area, the positive electrode notch and the negative electrode notch located on the same side alternately overlap to form a chamfer at the corner of the wound cell, and the size of the positive electrode notch gradually increases from the inner circle to the outer circle, and the size of the negative electrode notch gradually increases from the inner circle to the outer circle.

[0007] The wound cell of this invention forms a chamfer at the corner by alternately overlapping the positive and negative electrode notches on the same side in the same arc area. This reduces the stress exerted on the soft-pack battery casing by the corner during battery use, thereby avoiding the problem of corner breakage that easily occurs after the wound cell is formed into a soft-pack battery.

[0008] Therefore, the wound cell of the present invention can avoid the problem of corner breakage in the soft-pack casing after the wound cell is formed into a soft-pack battery.

[0009] In some embodiments, along the length of the wound cell, the positive electrode notch is provided on both sides of the positive electrode arc segment, and the negative electrode notch is provided on both sides of the negative electrode arc segment.

[0010] In some embodiments, in the length direction of the wound cell, a positive electrode notch is provided on one side edge of the positive electrode arc segment, and a negative electrode notch is provided on one side edge of the negative electrode arc segment, and the positive electrode notch and the negative electrode notch are located on the same side in the length direction of the wound cell.

[0011] In some embodiments, among adjacent positive and negative electrode notches in the same arc region, the size of the outer negative electrode notch is smaller than the size of the inner positive electrode notch.

[0012] In some embodiments, the width H of the negative electrode and the width h of the positive electrode satisfy: 50mm≤H≤120mm, 48.5mm≤h≤119.5mm, and 0.5mm≤Hh≤1.5mm.

[0013] In some embodiments, the positive electrode notch is trapezoidal, and the lower base of the positive electrode notch is located on the side edge in the width direction of the positive electrode sheet; the negative electrode notch is trapezoidal, and the lower base of the negative electrode notch is located on the side edge in the width direction of the negative electrode sheet.

[0014] In some embodiments, in the winding direction of the positive electrode sheet, the depth a of the positive electrode notch gradually increases, the lower base dimension c of the positive electrode notch gradually increases, and the upper base dimension e of the positive electrode notch gradually increases; in the winding direction of the negative electrode sheet, the depth b of the negative electrode notch gradually increases, the lower base dimension d of the negative electrode notch gradually increases, and the upper base dimension f of the negative electrode notch gradually increases.

[0015] In some embodiments, among adjacent positive and negative electrode notches in the same arc region, the depth a of the outer negative electrode notch is less than the depth b of the inner positive electrode notch; the lower base dimension d of the outer negative electrode notch is less than the lower base dimension c of the inner positive electrode notch; and the upper base dimension f of the outer negative electrode notch is less than the upper base dimension e of the inner positive electrode notch.

[0016] In some embodiments, the depth a of the positive electrode notch satisfies: 0.3mm≤a≤2mm; the depth b of the negative electrode notch satisfies: 0.0025h≤a≤0.04h.

[0017] In some embodiments, the depth a of the positive electrode notch and the width h of the positive electrode sheet satisfy: a≤0.05h; the depth b of the negative electrode notch and the width H of the negative electrode sheet satisfy: 0.0025H≤b≤0.04H.

[0018] In some embodiments, in the winding direction of the positive electrode sheet, the lower base dimension c of the positive electrode notch satisfies: 5mm≤c≤13mm; in the winding direction of the negative electrode sheet, the lower base dimension d of the negative electrode notch satisfies: 5mm≤d≤13mm.

[0019] In some embodiments, in the winding direction of the positive electrode sheet, the size e of the upper bottom of the positive electrode notch satisfies: 1mm≤e≤4mm; in the winding direction of the negative electrode sheet, the size f of the upper bottom of the negative electrode notch satisfies: 1mm≤f≤4mm.

[0020] The present invention also provides a battery.

[0021] The battery of this invention includes the wound cell described in the above embodiments. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is one of the structural schematic diagrams of the wound battery cell according to an embodiment of the present invention; Figure 2 This is a second schematic diagram of the structure of the wound battery cell according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the positive electrode sheet of the wound battery cell according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the negative electrode sheet of the wound battery cell according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of a soft-pack battery according to an embodiment of the present invention.

[0024] In the picture: 100. Winded cell; 110. Flat section; 120. Circular arc segment; 200. Battery; 210. Soft-pack casing; 1. Positive electrode plate; 101. Positive electrode arc segment; 102. Positive electrode notch; 2. Negative electrode sheet; 201. Negative electrode arc segment; 202. Negative electrode notch; 3. Diaphragm; 4. Chamfer. Detailed Implementation

[0025] To make the technical problems solved, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0026] In the description of this invention, it should be understood that the terms "longitudinal," "radial," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal encapsulation of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] In order to solve the problem that the wound cell 100 is prone to corner breakage after forming the soft-pack battery 200 in the related technology.

[0029] The wound battery cell 100 of this embodiment includes a positive electrode 1, a negative electrode 2 and a separator 3. The separator 3 is disposed between the positive electrode 1 and the negative electrode 2. The positive electrode 1, the negative electrode 2 and the separator 3 are stacked and arranged along the winding direction to form the wound battery cell 100. The wound battery cell 100 has a flat region 110 and arc regions disposed at both ends of the extension direction of the flat region 110. The positive electrode 1 has a positive arc segment 101 located in the arc region, and the negative electrode 2 has a negative arc segment 201 located in the arc region. In the same arc area, the positive electrode notch 102 and the negative electrode notch 202 located on the same side overlap alternately to form a chamfer 4 at the corner of the wound cell 100, and the size of the positive electrode notch 102 gradually increases from the inner circle to the outer circle, and the size of the negative electrode notch 202 gradually increases from the inner circle to the outer circle.

[0030] The corner of the wound cell 100 can be understood as the connection point of the edge of the wound cell 100. The edge of the wound cell 100 includes a top edge, a left edge, a bottom edge and a right edge connected in sequence. The corner of the wound cell 100 is formed at the connection point of the above-mentioned edges, and the above-mentioned edges can form four corners. Therefore, forming a chamfer 4 at the corner of the wound cell 100 can be understood as forming a chamfer 4 at at least one corner of the wound cell 100.

[0031] It is understandable that the length of the positive electrode arc segment 101 in the winding direction increases gradually along the winding direction. Therefore, the size of the positive electrode notch 102 is set to increase gradually from the inner circle to the outer circle to accommodate the gradually increasing positive electrode arc segment 101. Similarly, the length of the negative electrode arc segment 201 in the winding direction increases gradually along the winding direction. Therefore, the size of the negative electrode notch 202 is set to increase gradually from the inner circle to the outer circle to accommodate the gradually increasing negative electrode arc segment 201. At the same time, the above settings also allow the positive electrode notch 102 and the negative electrode notch 202 to better form the chamfer 4.

[0032] If the two ends of the positive electrode 1 along its length are located within the arc area, then notches are provided at the two ends of the positive electrode 1 along its length to accommodate other positive electrode notches 102, thereby better forming the chamfer 4; similarly, if the two ends of the negative electrode 2 along its length are located within the arc area, then notches are provided at the two ends of the negative electrode 2 along its length to accommodate other negative electrode notches 202, thereby better forming the chamfer 4.

[0033] Furthermore, it can be understood that the size of the positive electrode notch 102 is set to increase gradually from the inner circle to the outer circle. This means that all the dimensions of the positive electrode notch 102 increase gradually from the inner circle to the outer circle. In other words, after the positive electrode sheet 1 is wound to form the wound cell 100, in the thickness direction of the positive electrode sheet 1, the edge of the larger positive electrode notch 102 is located outside the edge of the smaller positive electrode notch 102. Similarly, the size of the negative electrode notch 202 is set to increase gradually from the inner circle to the outer circle. This means that all the dimensions of the negative electrode notch 202 increase gradually from the inner circle to the outer circle. In other words, after the negative electrode sheet 2 is wound to form the wound cell 100, in the thickness direction of the negative electrode sheet 2, the edge of the larger negative electrode notch 202 is located outside the edge of the smaller negative electrode notch 202.

[0034] In this embodiment of the invention, the wound cell 100 forms a chamfer 4 at the corner of the wound cell 100 by alternately overlapping the positive electrode notch 102 and the negative electrode notch 202 located on the same side in the same arc area. This reduces the stress exerted on the soft-pack casing 210 of the soft-pack battery 200 by the corner during the use of the battery 200, thereby avoiding the problem of corner breakage that easily occurs after the wound cell 100 is formed into the soft-pack battery 200.

[0035] Therefore, the wound cell 100 of the present invention can avoid the problem that the soft-pack casing 210 is prone to breakage after the wound cell 100 is formed into the soft-pack battery 200.

[0036] In some embodiments, positive electrode notches 102 are provided on both sides of the positive electrode arc segment 101 and negative electrode notches 202 are provided on both sides of the negative electrode arc segment 201 along the length direction of the wound cell 100.

[0037] It is understandable that the length direction of the wound cell 100 is the same as the width direction of the positive electrode 1 and the width direction of the negative electrode 2. That is to say, in the length direction of the wound cell 100, the positive electrode arc segment 101 has a positive electrode notch 102 on both sides and the negative electrode arc segment 201 has a negative electrode notch 202 on both sides, which means that the corners of the wound cell 100 are formed with chamfers 4.

[0038] In some embodiments, a positive electrode notch 102 is provided on one side edge of the positive electrode arc segment 101 and a negative electrode notch 202 is provided on one side edge of the negative electrode arc segment 201 along the length direction of the wound cell 100, and the positive electrode notch 102 and the negative electrode notch 202 are located on the same side along the length direction of the wound cell 100.

[0039] It is understandable that the length direction of the wound cell 100 is the same as the width direction of the positive electrode 1 and the width direction of the negative electrode 2. That is to say, in the length direction of the wound cell 100, the positive electrode arc segment 101 and the negative electrode arc segment 201 are respectively provided on the side edge of the same side.

[0040] In other words, the wound cell 100 can also form the above-mentioned chamfer 4 at one corner, or at two corners, or at multiple corners. The specific setting method can be set according to actual needs, and will not be elaborated here.

[0041] In some embodiments, among adjacent positive electrode notches 102 and negative electrode notches 202 in the same arc region, the size of the negative electrode notch 202 located on the outer side is smaller than the size of the positive electrode notch 102 located on the inner side.

[0042] Specifically, among the adjacent positive electrode notches 102 and negative electrode notches 202 located on the same side and at the same end in the length direction of the wound cell 100, the size of the negative electrode notch 202 located on the outer side is smaller than the size of the positive electrode notch 102 located on the inner side.

[0043] It is understandable that the size of the negative electrode notch 202 located on the outside is smaller than the size of the positive electrode notch 102 located on the inside. This means that the edge of the negative electrode notch 202 located on the outside is located inside the edge of the positive electrode notch 102 located on the inside, so that the edge of the negative electrode 2 is located outside the edge of the positive electrode 1, which can avoid the problem of lithium plating and thus avoid affecting the performance of the wound cell 100.

[0044] In some embodiments, the width H of the negative electrode 2 and the width h of the positive electrode 1 satisfy: 50mm≤H≤120mm, 48.5mm≤h≤119.5mm, and 0.5mm≤Hh≤1.5mm.

[0045] Preferably, the width H of the negative electrode 2 is 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, or 120mm.

[0046] Preferably, the width h of the positive electrode 1 is 48.5mm, 58.5mm, 68.5mm, 78.5mm, 88.5mm, 98.5mm, 108.5mm, 118.5mm and 119.5mm.

[0047] Preferably, Hh is 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, or 1.5mm.

[0048] It is understandable that "Hh" refers to the difference between the width H of the negative electrode 2 and the width h of the positive electrode 1, i.e., the size of the overhang region of the wound cell 100. If the size of this region is too small, lithium plating is likely to occur; if the size of this region is too large, it will excessively increase the size of the wound cell 100, thereby affecting the energy density of the wound cell 100. Therefore, by setting the difference between the width H of the negative electrode 2 and the width h of the positive electrode 1 within the above range, it is possible to avoid lithium plating while avoiding affecting the energy density of the wound cell 100.

[0049] In some embodiments, the positive electrode notch 102 is trapezoidal, and the lower base of the positive electrode notch 102 is located on the side edge in the width direction of the positive electrode sheet 1; the negative electrode notch 202 is trapezoidal, and the lower base of the negative electrode notch 202 is located on the side edge in the width direction of the negative electrode sheet 2.

[0050] It is understandable that the cross-section of the arc region is two semicircles, so the cross-section of the positive arc segment 101 includes two quarter-circles. One end of one quarter-circle is connected to one end of the other quarter-circle, and the other end of one quarter-circle is connected to the positive electrode plate 1 of the flat region 110. The other quarter-circle is connected to the arc segment 120 of the flat region 110. That is to say, the degree of winding of the positive electrode plate 1 at the connection of the two quarter-circles is the greatest. As a result, in the subsequent use of the wound cell 100, due to the increase in volume, the stress on the positive electrode notch 102 at the connection of the two quarter-circles is the greatest, which is prone to tearing the edge of the positive electrode notch 102. Therefore, by setting the positive electrode notch 102 as a trapezoid, the upper base of the positive electrode notch 102 is located at the connection of two quarter-circle arcs. In other words, the edge of the positive electrode notch 102 is set to extend along the winding direction of the positive electrode sheet 1 at the position where the winding degree of the positive electrode sheet 1 is the greatest. This can reduce the stress on the edge of the positive electrode notch 102 due to volume changes in the wound cell 100 during subsequent use, thereby avoiding the problem of tearing of the positive electrode notch 102 and further improving the safety performance of the wound cell 100 in this embodiment of the invention. Similarly, since the cross-section of the arc region is two semicircles, the cross-section of the negative arc segment 201 includes two quarter-circles. One end of one quarter-circle is connected to one end of the other quarter-circle, and the other end of one quarter-circle is connected to the negative electrode sheet 2 of the flat region 110. The other quarter-circle is connected to the arc segment 120 of the flat region 110. In other words, the degree of winding of the negative electrode sheet 2 at the connection of the two quarter-circles is the greatest. Consequently, in the subsequent use of the wound cell 100, due to the increase in volume, the stress on the negative electrode notch 202 at the connection of the two quarter-circles is the greatest, which is prone to tearing the edge of the negative electrode notch 202. Therefore, by setting the negative electrode notch 202 as a trapezoid, the upper base of the negative electrode notch 202 is located at the connection of two quarter-circle arcs. In other words, the edge of the negative electrode notch 202 is set to extend along the winding direction of the negative electrode sheet 2 at the position where the winding degree of the negative electrode sheet 2 is the greatest. This can reduce the stress on the edge of the negative electrode notch 202 due to volume changes in the wound cell 100 during subsequent use, thereby avoiding the problem of tearing of the negative electrode notch 202 and further improving the safety performance of the wound cell 100 in this embodiment of the invention.

[0051] In some embodiments, in the winding direction of the positive electrode sheet 1, the depth a of the positive electrode notch 102 gradually increases, the lower base dimension c of the positive electrode notch 102 gradually increases, and the upper base dimension e of the positive electrode notch 102 gradually increases; in the winding direction of the negative electrode sheet 2, the depth b of the negative electrode notch 202 gradually increases, the lower base dimension d of the negative electrode notch 202 gradually increases, and the upper base dimension f of the negative electrode notch 202 gradually increases.

[0052] By limiting the dimensions of the positive electrode notch 102 and the negative electrode notch 202, the positive electrode notch 102 can be adapted to the dimensions of the positive electrode arc segment 101 in which it is located, and the negative electrode notch 202 can also be adapted to the dimensions of the negative electrode arc segment 201 in which it is located.

[0053] In some embodiments, among adjacent positive electrode notches 102 and negative electrode notches 202 in the same arc region, the depth b of the negative electrode notch 202 located on the outer side is less than the depth a of the positive electrode notch 102 located on the inner side, the lower base dimension d of the negative electrode notch 202 located on the outer side is less than the lower base dimension c of the positive electrode notch 102 located on the inner side, and the upper base dimension f of the negative electrode notch 202 located on the outer side is less than the upper base dimension e of the positive electrode notch 102 located on the inner side.

[0054] By defining the relationship between the dimensions of the positive electrode notch 102 and the negative electrode notch 202, the edge of the negative electrode notch 202 located on the outside can be located inside the edge of the positive electrode notch 102 located on the inside, thereby making the edge of the negative electrode 2 located outside the edge of the positive electrode 1, thus avoiding the problem of lithium plating, and thus avoiding affecting the performance of the wound cell 100.

[0055] In some embodiments, the depth a of the positive electrode notch 102 satisfies: 0.3mm≤a≤2mm; the depth b of the negative electrode notch 202 satisfies: 0.3mm≤b≤2mm.

[0056] Preferably, the depth 'a' of the positive electrode notch 102 is 0.3 mm, 0.7 mm, 1.1 mm, 1.3 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, or 2.0 mm.

[0057] Preferably, the depth b of the negative electrode notch 202 is 0.3mm, 0.7mm, 1.1mm, 1.3mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, or 2.0mm.

[0058] It is understandable that if the depth a of the positive electrode notch 102 and the depth b of the negative electrode notch 202 are too small, the resulting rounded corners will be small, and the improvement on the corner damage problem of the aluminum-plastic film shell will not be significant. If the depth a of the positive electrode notch 102 and the depth b of the negative electrode notch 202 are too large, the active material of the positive electrode sheet 1 and the negative electrode sheet 2 will be greatly reduced, thereby reducing the energy density of the wound cell.

[0059] Therefore, by setting the depth a of the positive electrode notch 102 and the depth b of the negative electrode notch 202 to the above range, the corner damage problem of the aluminum-plastic film shell can be effectively improved, and the excessive impact on the energy density of the wound cell can be avoided.

[0060] In some embodiments, the depth a of the positive electrode notch 102 and the width h of the positive electrode plate 1 satisfy: 0.0025h≤a≤0.04h; the depth b of the negative electrode notch 202 and the width H of the negative electrode plate 2 satisfy: 0.0025H≤b≤0.04H.

[0061] It is understandable that if the proportion of the depth a of the positive electrode notch 102 to the width h of the positive electrode sheet 1 and the proportion of the depth b of the negative electrode notch 202 to the width H of the negative electrode sheet 2 are too small, the improvement on the corner damage problem of the aluminum-plastic film shell will not be significant; if the proportion of the depth a of the positive electrode notch 102 to the width h of the positive electrode sheet 1 and the proportion of the depth b of the negative electrode notch 202 to the width H of the negative electrode sheet 2 are too large, the active material of the positive electrode sheet 1 and the negative electrode sheet 2 will be greatly reduced, thereby reducing the energy density of the wound cell.

[0062] Therefore, by setting the proportion of the depth a of the positive electrode notch 102 to the width h of the positive electrode sheet 1 and the proportion of the depth b of the negative electrode notch 202 to the width H of the negative electrode sheet 2 within the aforementioned ranges, the corner damage problem of the aluminum-plastic film shell can be effectively improved, while avoiding excessive impact on the energy density of the wound cell. In some embodiments, in the winding direction of the positive electrode sheet 1, the lower base dimension c of the positive electrode notch 102 satisfies: 5mm ≤ c ≤ 13mm; in the winding direction of the negative electrode sheet 2, the lower base dimension d of the negative electrode notch 202 satisfies: 5mm ≤ d ≤ 13mm.

[0063] Preferably, the bottom dimension c of the positive electrode notch 102 is 5mm, 6.3mm, 7.8mm, 8.5mm, 9.2mm, 10.7mm, 11.4mm, 12.1mm, 12.6mm, or 13mm.

[0064] Preferably, the bottom dimension d of the negative electrode notch 202 is 5mm, 6.3mm, 7.8mm, 8.5mm, 9.2mm, 10.7mm, 11.4mm, 12.1mm, 12.6mm, or 13mm.

[0065] It is understandable that if the bottom dimension c of the positive electrode notch 102 is too small, it will not effectively improve the problem of corner damage to the aluminum-plastic film shell; if the bottom dimension c of the positive electrode notch 102 is too large, it will occupy too much area of ​​the positive electrode sheet 1, resulting in a reduction of the active material in the positive electrode sheet 1 and affecting the energy density of the core. Similarly, if the bottom dimension c of the negative electrode notch 202 is too small, it will not effectively improve the problem of corner damage to the aluminum-plastic film shell; if the bottom dimension c of the negative electrode notch 202 is too large, it will occupy too much area of ​​the positive electrode sheet 1, resulting in a reduction of the active material in the positive electrode sheet 1 and affecting the energy density of the core.

[0066] Therefore, by setting the bottom dimensions c of the positive electrode notch 102 and the bottom dimensions d of the negative electrode notch 202 within the above range, the problem of corner damage of the aluminum-plastic film shell can be effectively improved while ensuring that the wound cell has a good energy density.

[0067] In some embodiments, in the winding direction of the positive electrode 1, the size e of the upper bottom of the positive electrode notch 102 satisfies: 1mm≤e≤4mm; in the winding direction of the negative electrode 2, the size f of the upper bottom of the negative electrode notch 202 satisfies: 1mm≤f≤4mm.

[0068] Preferably, the size e of the upper bottom of the positive electrode notch 102 is 1.0mm, 1.4mm, 1.9mm, 2.3mm, 2.7mm, 3.1mm, 3.4mm, 3.6mm, 3.8mm, or 4.0mm.

[0069] Preferably, the size f of the upper bottom of the negative electrode notch 202 is 1.0mm, 1.4mm, 1.9mm, 2.3mm, 2.7mm, 3.1mm, 3.4mm, 3.6mm, 3.8mm, or 4.0mm.

[0070] It is understandable that if the upper bottom dimension e of the positive electrode notch 102 is too small, the improvement effect on the corner damage problem of the aluminum-plastic film shell will be limited; if the upper bottom dimension e of the positive electrode notch 102 is too large, on the one hand, it will further expand the area of ​​the positive electrode sheet 1 occupied by the notch, resulting in a reduction in the load of active material on the positive electrode sheet 1, which directly affects the energy density of the core; on the other hand, it may damage the structural integrity of the positive electrode sheet 1, leading to a decrease in the force balance during winding, and thus affecting the overall mechanical stability of the cell. Similarly, if the upper bottom dimension f of the negative electrode notch 202 is too small, it will be difficult to achieve the expected effect of improving the corner damage of the aluminum-plastic film shell; if the upper bottom dimension f of the negative electrode notch 202 is too large, it will occupy the effective area of ​​the negative electrode sheet 2, thereby reducing the active material load of the negative electrode sheet 2. This will not only affect the energy density of the core, but may also lead to an imbalance in the ratio of positive and negative electrode materials, indirectly affecting the electrochemical performance of the cell. At the same time, it will also weaken the structural strength of the negative electrode sheet 2, which is not conducive to the stability of the winding process and the long-term reliability of the cell. Therefore, by setting the upper bottom dimension e of the positive electrode notch 102 and the upper bottom dimension f of the negative electrode notch 202 within the range of 1mm≤e≤4mm and 1mm≤f≤4mm, it is possible to ensure the improvement effect on the corner damage problem of the aluminum-plastic film shell, and strictly control the electrode area occupied by the notch to avoid excessive reduction of active material. Thus, while ensuring that the core has a good energy density, it also takes into account the structural stability and electrochemical performance of the cell, achieving the dual technical goal of improving the damage problem and ensuring the core performance.

[0071] The present invention also provides a battery 200.

[0072] The battery 200 of this embodiment includes the wound cell 100 as described in the above embodiment.

[0073] Specifically, the battery 200 in this embodiment of the invention also includes a soft-pack housing 210, wherein the wound cell 100 is disposed inside the soft-pack housing 210, which can avoid the problem of the battery 200 in this embodiment of the invention having broken corners.

[0074] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A wound battery cell, characterized in that, The device includes a positive electrode (1), a negative electrode (2), and a separator (3). The separator (3) is disposed between the positive electrode (1) and the negative electrode (2). The positive electrode (1), the negative electrode (2), and the separator (3) are stacked and arranged along the winding direction to form the wound battery cell. The wound battery cell has a flat region (110) and arc regions at both ends of the extension direction of the flat region (110). The positive electrode (1) has a positive arc segment (101) located in the arc region, and the negative electrode (2) has a negative arc segment (201) located in the arc region. In the same arc area, the positive electrode notch (102) and the negative electrode notch (202) located on the same side overlap alternately to form a chamfer (4) at the corner of the wound cell, and the size of the positive electrode notch (102) gradually increases from the inner circle to the outer circle, and the size of the negative electrode notch (202) gradually increases from the inner circle to the outer circle.

2. The wound battery cell according to claim 1, characterized in that, Along the length of the wound cell, the positive electrode notch (102) is provided on both sides of the positive electrode arc segment (101), and the negative electrode notch (202) is provided on both sides of the negative electrode arc segment (201).

3. The wound battery cell according to claim 1, characterized in that, Along the length of the wound cell, a positive electrode notch (102) is provided on one side edge of the positive electrode arc segment (101), and a negative electrode notch (202) is provided on one side edge of the negative electrode arc segment (201), and the positive electrode notch (102) and the negative electrode notch (202) are located on the same side along the length of the wound cell.

4. The wound battery cell according to claim 1, characterized in that, In the adjacent positive electrode notch (102) and negative electrode notch (202) in the same arc region, the size of the negative electrode notch (202) located on the outer side is smaller than the size of the positive electrode notch (102) located on the inner side.

5. The wound battery cell according to claim 1, characterized in that, The width H of the negative electrode (2) and the width h of the positive electrode (1) satisfy: 50mm≤H≤120mm, 48.5mm≤h≤119.5mm, and 0.5mm≤Hh≤1.5mm.

6. The wound battery cell according to claim 5, characterized in that, The positive electrode notch (102) is trapezoidal, and the lower base of the positive electrode notch (102) is located on the side edge of the positive electrode sheet (1) in the width direction; the negative electrode notch (202) is trapezoidal, and the lower base of the negative electrode notch (202) is located on the side edge of the negative electrode sheet (2) in the width direction.

7. The wound battery cell according to claim 6, characterized in that, In the winding direction of the positive electrode sheet (1), the depth a of the positive electrode notch (102) gradually increases, the lower base dimension c of the positive electrode notch (102) gradually increases, and the upper base dimension e of the positive electrode notch (102) gradually increases; in the winding direction of the negative electrode sheet (2), the depth b of the negative electrode notch (202) gradually increases, the lower base dimension d of the negative electrode notch (202) gradually increases, and the upper base dimension f of the negative electrode notch (202) gradually increases.

8. The wound battery cell according to claim 6, characterized in that, In the adjacent positive electrode notch (102) and negative electrode notch (202) in the same arc region, the depth a of the negative electrode notch (202) located on the outer side is less than the depth b of the positive electrode notch (102) located on the inner side; the lower base dimension d of the negative electrode notch (202) located on the outer side is less than the lower base dimension c of the positive electrode notch (102) located on the inner side; and the upper base dimension f of the negative electrode notch (202) located on the outer side is less than the upper base dimension e of the positive electrode notch (102) located on the inner side.

9. The wound battery cell according to claim 6, characterized in that, The depth a of the positive electrode notch (102) satisfies: 0.3mm≤a≤2mm; the depth b of the negative electrode notch (202) satisfies: 0.3mm≤b≤2mm.

10. The wound battery cell according to claim 6, characterized in that, The depth a of the positive electrode notch (102) and the width h of the positive electrode sheet (1) satisfy: 0.0025h≤a≤0.04h; the depth b of the negative electrode notch (202) and the width H of the negative electrode sheet (2) satisfy: 0.0025H≤b≤0.04H.

11. The wound battery cell according to claim 6, characterized in that, In the winding direction of the positive electrode (1), the bottom dimension c of the positive electrode notch (102) satisfies: 5mm≤c≤13mm; in the winding direction of the negative electrode (2), the bottom dimension d of the negative electrode notch (202) satisfies: 5mm≤d≤13mm.

12. The wound battery cell according to claim 6, characterized in that, In the winding direction of the positive electrode (1), the size e of the upper bottom of the positive electrode notch (102) satisfies: 1mm≤e≤4mm; in the winding direction of the negative electrode (2), the size f of the upper bottom of the negative electrode notch (202) satisfies: 1mm≤f≤4mm.

13. A battery, characterized in that, Includes the wound cell (100) as described in any one of claims 1-12.

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