Winding type battery cell and battery

Abstract

The utility model relates to the technical field of batteries, and provides a winding type battery cell and a battery. The winding type battery cell comprises a battery cell main body, a tab and at least one insulating film, the battery cell main body comprises a first pole piece, the first pole piece comprises a first current collector and a first active substance layer, the first active substance layer comprises a first flat coating area and a first thinning area, the thickness of the first flat coating area is greater than that of the first thinning area, and the first current collector is arranged on the first pole piece; at least one end of the first active material layer comprises a first thinning area in the direction in which the tabs extend out of the battery cell main body; in the winding direction of the first pole piece, the first straight sections and the first bent sections are alternately arranged, at least one first bent section is provided with an insulating film, and the ratio of the height of the insulating film to the height of the first active substance layer is 85%-98% in the direction in which the tabs extend out of the battery cell main body; therefore, the insulation film can be prevented from falling off due to the fact that the fixing strength between the insulation film and the first thinning area is relatively weak and edge warping occurs at the end part, so that the safe use performance of the winding type battery cell is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a winding type battery core and a battery. Background Art

[0002] In the related art, the positive electrode sheet and the negative electrode sheet of the battery cell respectively include a positive electrode active material layer and a negative electrode active material layer. During the battery cell forming process, the active material layer on the current collector may fall off, thereby causing an internal short circuit problem in the battery, affecting the safe use performance of the battery. Utility Model Content

[0003] The utility model provides a winding type electric core and a battery to improve the use performance of the battery.

[0004] According to a first aspect of the utility model, a wound battery cell is provided, comprising a battery cell body, a pole ear and at least one insulating film, wherein the pole ear extends from the battery cell body, and the battery cell body comprises:

[0005] A first pole piece, the first pole piece comprises a first current collector and a first active material layer, the first active material layer is arranged on the first current collector, the first active material layer comprises a first flat coating area and a first thinning area, the thickness of the first flat coating area is greater than the first thinning area, along the direction in which the pole ear extends from the battery body, at least one end of the first active material layer comprises the first thinning area, and at least one end of the first flat coating area is connected to the first thinning area;

[0006] Among them, the first active material layer is wound to form a plurality of first straight sections and a plurality of first bent sections. Along the winding direction of the first pole piece, the first straight sections and the first bent sections are alternately arranged. An insulating film is arranged on at least one first bent section. Along the direction in which the pole ear extends from the battery cell body, the ratio of the height of the insulating film to the height of the first active material layer is 85%-98%.

[0007] A wound cell of one embodiment of the utility model comprises a cell body, a pole ear and at least one insulating film, the first pole piece of the cell body comprises a first current collector and a first active material layer, by making at least one end of the first active material layer include a first thinning area, that is, the thickness of the first flat coating area can be greater than the first thinning area, so that the risk of the first current collector being broken during the winding process can be reduced, and along the winding direction of the first pole piece, the first active material layer comprises a plurality of first straight sections and a plurality of first bending sections, by providing an insulating film on at least one first bending section, the risk of the first active material layer falling off due to the stress concentration of the first bending section during the winding process of the wound cell can be avoided, and the risk of dendrites or foreign objects piercing the first current collector can be reduced. Considering the existence of the first thinning area, by making the ratio of the height of the insulating film to the height of the first active material layer 85%-98%, it can be avoided that the insulating film and the first thinning area are fixed with weak strength, and the end warping occurs, resulting in the insulation film falling off, thereby ensuring the safe use performance of the wound cell.

[0008] According to a second aspect of the utility model, a battery is provided, comprising the above-mentioned wound battery cell.

[0009] The wound cell of a battery of one embodiment of the utility model comprises a cell body, a pole ear and at least one insulating film, the first pole piece of the cell body comprises a first current collector and a first active material layer, by making at least one end of the first active material layer include a first thinning area, that is, the thickness of the first flat coating area can be greater than the first thinning area, so that the risk of the first current collector being broken during the winding process can be reduced, and along the winding direction of the first pole piece, the first active material layer comprises a plurality of first straight sections and a plurality of first bending sections, by providing an insulating film on at least one first bending section, the risk of the first active material layer falling off due to the stress concentration of the first bending section during the winding process of the wound cell can be avoided, and the risk of dendrites or foreign objects piercing the first current collector can be reduced. Considering the existence of the first thinning area, by making the ratio of the height of the insulating film to the height of the first active material layer 85%-98%, it can be avoided that the insulating film and the first thinning area are fixed with weak strength, and the end warping occurs, resulting in the insulating film falling off, thereby ensuring the safe use performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to better understand the present disclosure, reference may be made to the embodiments shown in the following drawings. The components in the drawings are not necessarily to scale, and related elements may be omitted in order to emphasize and clearly illustrate the technical features of the present disclosure. In addition, related elements or components may have different arrangements as known in the art. In addition, in the drawings, the same reference numerals represent the same or similar components in each drawing. Among them:

[0011] Figure 1 is a schematic structural diagram of a wound battery cell according to an exemplary embodiment;

[0012] Figure 2 is a schematic cross-sectional structure diagram of a wound battery cell according to an exemplary embodiment;

[0013] Figure 3 is a partial structural schematic diagram of a wound-type battery cell according to an exemplary embodiment;

[0014] Figure 4 is a partial structural schematic diagram of a wound-type battery cell according to another exemplary embodiment;

[0015] Figure 5 is a schematic diagram of a cross-sectional structure of a first pole piece of a wound battery cell according to an exemplary embodiment;

[0016] Figure 6 is a schematic cross-sectional structure diagram of a first pole piece and an insulating film of a wound-type battery cell according to a first exemplary embodiment;

[0017] Figure 7 is a schematic cross-sectional structure diagram of a first pole piece and an insulating film of a wound-type battery cell according to a second exemplary embodiment;

[0018] Figure 8 is a schematic cross-sectional structure diagram of a first pole piece and an insulating film of a wound-type battery cell according to a third exemplary embodiment;

[0019] Fig. 9 is a schematic cross-sectional structure diagram of a first pole piece and an insulating film of a wound-type battery cell according to a fourth exemplary embodiment;

[0020] Fig.10 is a schematic cross-sectional structure diagram of a second pole piece and an insulating film of a wound-type battery cell according to an exemplary embodiment;

[0021] Fig.11 is a schematic structural diagram of a battery according to an exemplary embodiment.

[0022] The following are the descriptions of the reference numerals:

[0023] 10. Battery cell body; 11. First pole piece; 111. First current collector; 112. First active material layer; 1121. First flat coating area; 1122. First thinning area; 1123. First straight section; 1124. First bending section; 12. Second pole piece; 121. Second current collector; 122. Second active material layer; 1221. Second flat coating area; 1222. Second thinning area; 1223. Second straight section; 1224. Second bending section; 13. Diaphragm; 20. Tab; 30. Insulating film; 40. Adhesive layer; 50. Battery case; 60. Post assembly. DETAILED DESCRIPTION

[0024] The following will be combined with the accompanying drawings in the exemplary embodiments of the present disclosure to clearly and completely describe the technical solutions in the exemplary embodiments of the present disclosure. The exemplary embodiments described herein are only for illustrative purposes and are not intended to limit the scope of protection of the present disclosure. Therefore, it should be understood that various modifications and changes can be made to the exemplary embodiments without departing from the scope of protection of the present disclosure.

[0025] In the description of the present disclosure, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; the term "plurality" refers to two or more; the term "and / or" includes any and all combinations of one or more associated listed items. In particular, reference to "the / the" object or "an" object is also intended to indicate one of a possible plurality of such objects.

[0026] Unless otherwise specified or explained, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, an electrical connection, or a signal connection; "connection" can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in this disclosure can be understood according to specific circumstances.

[0027] Further, in the description of the present disclosure, it should be understood that the directional words such as "upper", "lower", "inner", "outer" and the like described in the exemplary embodiments of the present disclosure are described at the angles shown in the accompanying drawings and should not be understood as limitations on the exemplary embodiments of the present disclosure. It should also be understood that, in the context, when it is mentioned that an element or feature is connected to another element (one or more) "upper", "lower", or "inner", "outer", it can not only be directly connected to the other (one or more) elements "upper", "lower", "inner", "outer", but also can be indirectly connected to the other (one or more) elements "upper", "lower", "inner", "outer" through an intermediate element.

[0028] An embodiment of the present invention provides a wound battery cell, please refer to Figures 1 to 10 , including a battery body 10, a pole ear 20 and at least one insulating film 30, the pole ear 20 extends from the battery body 10, the battery body 10 includes: a first pole piece 11, the first pole piece 11 includes a first current collector 111 and a first active material layer 112, the first active material layer 112 is arranged on the first current collector 111, the first active material layer 112 includes a first flat coating area 1121 and a first thinning area 1122, the thickness of the first flat coating area 1121 is greater than that of the first thinning area 1122, and the first active material layer 112 is from the battery body 10 to the first flat coating area 1121. At least one end includes a first thinning area 1122, and at least one end of the first flat coating area 1121 is connected to the first thinning area 1122; wherein, the first active material layer 112 is wound to form a plurality of first straight sections 1123 and a plurality of first bent sections 1124, and along the winding direction of the first pole piece 11, the first straight sections 1123 and the first bent sections 1124 are alternately arranged, and at least one first bent section 1124 is provided with an insulating film 30, and along the direction in which the pole ear 20 extends from the battery cell body 10, the ratio of the height of the insulating film 30 to the height of the first active material layer 112 is 85%-98%.

[0029] A wound battery cell according to an embodiment of the utility model includes a battery cell body 10, a pole ear 20 and at least one insulating film 30. The first pole piece 11 of the battery cell body 10 includes a first current collector 111 and a first active material layer 112. By making at least one end of the first active material layer 112 include a first thinning area 1122, that is, the thickness of the first flat coating area 1121 can be greater than the first thinning area 1122, the risk of the first current collector 111 being broken during the winding process can be reduced. Along the winding direction of the first pole piece 11, the first active material layer 112 is wound to form a plurality of first straight sections 1123 and a plurality of first bent sections 1124. By providing an insulating film 30 on at least one first bent section 1124, the risk of the first active material layer 112 falling off due to stress concentration in the first bent section 1124 during the winding process of the wound battery cell can be avoided, and the risk of dendrites or foreign matter piercing the first current collector 111 can be reduced. Taking into account the existence of the first thinning area 1122, by making the ratio of the height of the insulating film 30 to the height of the first active material layer 112 be 85%-98%, it is possible to avoid end warping due to weak fixing strength between the insulating film 30 and the first thinning area 1122, which may cause the insulating film 30 to fall off, thereby ensuring the safe use performance of the wound battery cell.

[0030] It should be noted that, combined with Figures 1 to 4As shown, the wound battery cell may include a first pole piece 11, a second pole piece 12 and a diaphragm 13. The diaphragm 13 may be arranged between the first pole piece 11 and the second pole piece 12. The battery cell is wound on a winding core rod to form a cylindrical structure. After the winding core rod is taken out, the cylindrical structure may be flattened to form a wound battery cell. At this time, a pole ear 20 extends from the battery body 10 of the wound battery cell.

[0031] The tabs 20 include a positive tab and a negative tab, which extend from the same end of the battery body 10, thereby reducing the overall height of the wound battery cell, which is beneficial to improving the overall energy density of the cylindrical battery. Alternatively, the positive tab and the negative tab may extend from opposite ends of the battery body 10, respectively. The positive tab and the negative tab may extend from the positive electrode sheet and the negative electrode sheet, respectively.

[0032] The first electrode sheet 11 includes a first current collector 111 and a first active material layer 112 . The first current collector 111 may be a metal foil. The first active material layer 112 is coated on the first current collector 111 , and then a wound battery cell is formed by a winding process.

[0033] The first current collector 111 may be copper, aluminum or a composite material. For example, the first current collector 111 includes a polymer base film layer and a metal layer disposed on the polymer base film layer. The metal layer may be copper or aluminum, and the polymer base film layer may be made of polypropylene (OPP) or polyethylene terephthalate (PET). The first active material layer 112 may be a positive electrode material, for example, lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium titanate, etc. Alternatively, the first active material layer 112 may be a negative electrode material, for example, graphite, hard carbon, soft carbon, mesophase carbon microspheres, silicon carbon, and lithium titanate, etc.

[0034] During the coating process of the first active material layer 112, a first flat coating area 1121 and a first thinning area 1122 may be formed. The thickness of the first flat coating area 1121 is basically consistent, and the first thinning area 1122 may be a structure with basically consistent thickness, or the first thinning area 1122 may be a variable thickness structure. It only needs to ensure that the thickness of the first flat coating area 1121 is greater than the thickness of the first thinning area 1122.

[0035] Along the direction in which the tab 20 extends from the battery body 10, one end of the first active material layer 112 may include a first thinning region 1122, or both opposite ends of the first active material layer 112 may include a first thinning region 1122. Figure 3 shown.

[0036] Combination Figures 5 to 9As shown, after the cylindrical structure is flattened to form a wound battery cell, the first active material layer 112 may include a plurality of first straight segments 1123 and a plurality of first bent segments 1124, and along the winding direction of the first pole piece 11, the first straight segments 1123 and the first bent segments 1124 are alternately arranged. At this time, the winding direction of the first pole piece 11 can be considered as the extension direction from the innermost end of the first pole piece 11 toward the outermost end of the first pole piece 11, and does not specifically refer to the winding direction during the formation of the wound battery cell.

[0037] The edge of the coating material area of ​​the first current collector 111 has a larger thickness than the middle material area due to sagging accumulation. If the edge material area is not thinned, the first current collector 111 may be easily broken during the winding process, affecting the winding effect. Therefore, a thinning area is provided at the end of the first pole piece 11, that is, at least one end of the first active material layer 112 includes a first thinning area 1122, so as to ensure that the overall thickness of the first pole piece 11 is as uniform as possible. Due to the stress concentration at the bent part of the first pole piece 11 during the winding process, there is a risk of active material falling off. Therefore, there is a greater risk of dendrites or foreign matter piercing the first current collector 111, which in turn leads to the risk of positive and negative short circuits. The insulating film 30 is pasted to avoid coating falling off at the bend. However, the presence of the pole piece thinning area leads to weak fixing strength between the insulating film 30 and the first pole piece 11, and the end is warped, causing the insulating film 30 to fall off, causing battery safety risks. By making the ratio of the height of the insulating film 30 to the height of the first active material layer 112 in the direction extending from the battery body 10 along the pole ear 20 be 85%-98%, the insulating film 30 can form protection for the first active material layer 112, thereby reducing the risk of detachment of the insulating film 30, and thereby improving the safe use performance of the wound battery.

[0038] At least one end of the first active material layer 112 includes a first thinning area 1122, that is, at least one end of the first flat coating area 1121 is connected to the first thinning area 1122, for example, one end of the first flat coating area 1121 is connected to the first thinning area 1122, or both opposite ends of the first flat coating area 1121 are connected to the first thinning area 1122.

[0039] If the ratio of the height of the insulating film 30 to the height of the first active material layer 112 is too small, the first active material layer 112 is exposed too much, and the risk of the first active material layer 112 falling off increases, which is not conducive to reducing the risk of chipping. If the ratio of the height of the insulating film 30 to the height of the first active material layer 112 is too large, the height of the insulating film 30 is too large, and the size of the insulating film 30 covering the first thinned area 1122 will be large, which is not conducive to ensuring the stability of the insulating film 30.

[0040] The direction in which the tab 20 extends from the cell body 10 can be considered as the direction in which the tab 20 extends after the tab 20 is flattened. In the direction in which the tab 20 extends from the cell body 10, the ratio of the height of the insulating film 30 to the height of the first active material layer 112 can be 85%, 85.5%, 86%, 86.5%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97% or 98%, etc. The height of the insulating film 30 can be the height dimension obtained after the insulating film 30 is flattened.

[0041] In one embodiment, a first active material layer 112 is provided on two opposite sides of the first current collector 111; wherein, an insulating film 30 is provided on the first active material layer 112 on two opposite sides of the first current collector 111, thereby improving the protection of the first active material layer 112 by the insulating film 30 and reducing the risk of the first active material layer 112 falling off, which can not only improve the safe use performance of the wound battery cell, but also ensure the electrical performance of the wound battery cell.

[0042] In one embodiment, an insulating film 30 is disposed on the first bending section 1124 and the first flat coating area 1121 on opposite sides of the first current collector 111 .

[0043] In one embodiment, an insulating film 30 is provided on the first bending sections 1124 on opposite sides of the first current collector 111, so that the insulating film 30 can protect the first bending section 1124 which is most prone to falling risk, thereby minimizing the risk of falling off of the first active material layer 112.

[0044] In one embodiment, Figure 6 As shown, an insulating film 30 is provided on the first bending sections 1124 on the opposite sides of the same area of ​​the first current collector 111, so that the two opposite insulating films 30 can form effective protection for the two opposite first bending sections 1124, strengthen the protection of the first active material layer 112, and minimize the risk of the first active material layer 112 falling off.

[0045] In one embodiment, Figure 7 As shown, the insulating film 30 is disposed on the first bending segments 1124 on opposite sides of different regions of the first current collector 111 . For example, the insulating film 30 can be disposed on two first bending segments 1124 corresponding to two adjacent bending regions of the first current collector 111 .

[0046] In one embodiment, along the direction in which the pole ear 20 extends from the battery cell body 10, the ratio of the height of a single first thinning area 1122 to the height of the first active material layer 112 is 2%-15%, thereby effectively controlling the height dimension of the first thinning area 1122, reducing the surface tension of the coating on the edge of the first pole piece 11, and also ensuring the connection stability of the insulating film 30.

[0047] The ratio of the height of a single first thinning area 1122 to the height of the first active material layer 112 is too small, and the height of the first thinning area 1122 is too small to reduce the surface tension of the edge coating; while the ratio of the height of the first thinning area 1122 to the height of the first active material layer 112 is too large, and the height of the first thinning area 1122 is too large, which leads to a reduction in the connection area of ​​the insulating film 30 and the insulating film 30 is easy to fall off.

[0048] In the direction in which the tab 20 extends from the battery cell body 10, the ratio of the height of a single first thinning area 1122 to the height of the first active material layer 112 can be 2%, 2.5%, 3%, 3.5%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%, etc.

[0049] In one embodiment, along the direction in which the tab 20 extends from the battery cell body 10 , the height of the insulating film 30 covering the first thinning area 1122 is no more than 3 mm, thereby effectively reducing the coverage height of the insulating film 30 on the first thinning area 1122 , thereby ensuring the fixing ability of the insulating film 30 and reducing the risk of the insulating film 30 falling off.

[0050] The height of the insulating film 30 covering the first thinning area 1122 can be 3mm, 2.9mm, 2.8mm, 2.7mm, 2.6mm, 2.5mm, 2.4mm, 2.3mm, 2.2mm, 2.1mm, 2mm, 1.9mm, 1.8mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3mm, 1.2mm, 1.1mm, 1mm or 0.5mm, etc.

[0051] In one embodiment, along the direction in which the tab 20 extends from the battery cell body 10, the proportion of the insulating film 30 covering the first thinning area 1122 is no more than 40%. On the basis of ensuring that the insulating film 30 covers the first thinning area 1122, the insulating film 30 avoids excessive coverage of the first thinning area 1122, thereby ensuring the fixing ability of the insulating film 30, reducing the risk of the insulating film 30 falling off, and further improving the safety performance.

[0052] The ratio of the insulating film 30 covering the first thinned area 1122 along the direction in which the tab 20 extends from the battery body 10 is the ratio of the height of the insulating film 30 covering the first thinned area 1122 to the height of the first thinned area 1122 .

[0053] Along the direction in which the pole ear 20 extends from the battery cell body 10, the proportion of the insulating film 30 covering the first thinning area 1122 can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38, 39 or 40% and so on.

[0054] In one embodiment, along the winding direction of the first pole piece 11, the size of a single insulating film 30 is 5mm-30mm, which can not only ensure a larger coverage of the first bending section 1124 and reduce the shedding of the first active material layer 112 in the stress-relieving area, but also avoid the single insulating film 30 from being too large and occupying a large space, while also avoiding affecting the infiltration of the electrolyte.

[0055] Along the winding direction of the first pole piece 11 , the size of a single insulating film 30 is 5 mm-30 mm, that is, after the first pole piece 11 is flattened, along the length direction of the first pole piece 11 , the size of a single insulating film 30 is 5 mm-30 mm.

[0056] Combination Figure 6 As shown, the winding direction of the first pole piece 11 can be represented as X, which can be considered as the extension direction of the first pole piece 11. Along the winding direction of the first pole piece 11, the size of a single insulating film 30 can be the size obtained after the first pole piece 11 is flattened.

[0057] Along the winding direction of the first pole piece 11, the size of a single insulating film 30 can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm or 30mm, etc.

[0058] In one embodiment, the thickness of the first flat coating area 1121 is 60μm-280μm, thereby ensuring the electrical performance of the wound battery cell, and the thickness of the first flat coating area 1121 is relatively large, and the first bending section 1124 is more likely to fall off. Therefore, through the setting of the insulating film 30, the fixed protection of the first active material layer 112 can be more reasonably achieved.

[0059] The thickness of the first flat coating area 1121 can be 60μm, 65μm, 68μm, 70μm, 75μm, 78μm, 80μm, 85μm, 88μm, 90μm, 95μm, 98μm, 100μm, 105μm, 110μm, 115μm, 120μm, 125μm, 130μm, 135μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, 210μm, 220μm, 230μm, 240μm, 250μm, 260μm, 270μm or 280μm, etc.

[0060] The thickness of the first flat coating area 1121 is 60μm-280μm, that is, when the thickness of the first flat coating area 1121 is relatively large, the ratio of the height of the insulating film 30 to the height of the first active material layer 112 is 86%-98%, thereby ensuring that the insulating film 30 can have a sufficient coverage height to form an effective protection for the first active material layer 112, and can reduce the coverage height of the first thinning area 1122, thereby ensuring the fixing strength of the insulating film 30.

[0061] If the ratio of the height of the insulating film 30 to the height of the first active material layer 112 is too large, it is not conducive to the fixation of the insulating film 30, and the insulating film 30 is easily separated from the first thinned area 1122. If the ratio of the height of the insulating film 30 to the height of the first active material layer 112 is too small, it is not conducive to the insulating film 30 to protect the first active material layer 112.

[0062] In one embodiment, the insulating film 30 is bonded and fixed to the first pole piece 11 , thereby ensuring the fixing performance of the insulating film 30 and avoiding the risk of the insulating film 30 falling off.

[0063] In one embodiment, Figure 4 As shown, there is an adhesive layer 40 between the insulating film 30 and the first pole piece 11, and the ratio of the thickness of the adhesive layer 40 to the thickness of the first flat coating area 1121 is 0.7%-25%, thereby ensuring the adhesion of the insulating film 30, improving the fixing performance of the insulating film 30, and further improving the safe use performance of the wound battery cell.

[0064] The ratio of the thickness of the adhesive layer 40 to the thickness of the first flat coating area 1121 is too small, and the thickness of the adhesive layer 40 is too low, which cannot play the role of bonding the active material, and is not conducive to ensuring the fixing performance of the insulating film 30; the ratio of the thickness of the adhesive layer 40 to the thickness of the first flat coating area 1121 is too large, and the thickness of the adhesive layer 40 is too large, which not only has a high cost, but also causes stress concentration at the edges of the adhesive layer 40 and the insulating film 30, and damages the surface of the first pole piece 11 under high pressure, which is not conducive to ensuring the safety performance of the battery.

[0065] In one embodiment, there is an adhesive layer 40 between the insulating film 30 and the first pole piece 11, and the thickness of the adhesive layer 40 is 2μm-15μm, so that the thickness of the adhesive layer 40 can be adapted to the thickness of the first flat coating area 1121, thereby increasing the adhesion of the adhesive layer 40 and ensuring the fixing performance of the insulating film 30.

[0066] The thickness of the adhesive layer 40 can be 2um, 3um, 4um, 5um, 6um, 7um, 8um, 9um, 10um, 11um, 12um, 13um, 14um or 15um, etc.

[0067] In one embodiment, from the innermost layer of the battery body 10 to the outermost layer of the battery body 10 , at least one layer on at least the first four first bending sections 1124 is provided with an insulating film 30 , thereby minimizing the risk of the first active material layer 112 falling off.

[0068] The closer the first active material layer 112 is to the innermost layer of the battery cell body 10, the more serious the stress concentration problem of the first bending section 1124 thereof is. Therefore, the risk of the first active material layer 112 falling off will be greater. By providing an insulating film 30 on at least one of the first four first bending sections 1124 from the innermost layer of the battery cell body 10 toward the outermost layer of the battery cell body 10, the risk of the first active material layer 112 falling off can be effectively reduced.

[0069] In one embodiment, from the innermost layer of the battery cell body 10 toward the outermost layer of the battery cell body 10, at least one layer on at least the first four first bending sections 1124 of the same first active material layer 112 is provided with an insulating film 30, that is, at least one layer on at least the first four first bending sections 1124 of the first active material layer 112 on the same side of the first current collector 111 is provided with an insulating film 30, thereby effectively forming protection for the same layer of the first active material layer 112.

[0070] like Figure 8 As shown, an insulating film 30 may be disposed on the first four first bending sections 1124 of the same first active material layer 112 .

[0071] In one embodiment, Fig. 9As shown, from the innermost layer of the battery cell body 10 toward the outermost layer of the battery cell body 10 , an insulating film 30 is provided on at least the first four first bending sections 1124 relative to the two first active material layers 112 , thereby enabling the two relative insulating films 30 to effectively protect the two relative first active material layers 112 .

[0072] In one embodiment, the first electrode sheet 11 is a positive electrode sheet, that is, the first current collector 111 is a positive electrode current collector, and the first active material layer 112 is a positive electrode active material. The positive electrode current collector may be aluminum foil.

[0073] In one embodiment, the first electrode sheet 11 is a negative electrode sheet, that is, the first current collector 111 is a negative electrode current collector, and the first active material layer 112 is a negative electrode active material. The negative electrode current collector may be copper foil.

[0074] In one embodiment, Figure 3 and Figure 4 As shown, the battery body 10 also includes: a second pole piece 12, the second pole piece 12 is a positive pole piece, the second pole piece 12 includes a second current collector 121 and a second active material layer 122, the second active material layer 122 is arranged on the second current collector 121, the second active material layer 122 includes a second flat coating area 1221 and a second thinning area 1222, and in the direction in which the pole ear 20 extends from the battery body 10, at least one end of the second active material layer 122 includes the second thinning area 1222; wherein, the second active material layer 122 includes a plurality of second straight sections 1223 and a plurality of second bent sections 1224, and in the winding direction of the second pole piece 12, the second straight sections 1223 and the second bent sections 1224 are alternately arranged, and an insulating film 30 is arranged on at least one second bent section 1224, and in the direction in which the pole ear 20 extends from the battery body 10, the ratio of the height of the insulating film 30 to the height of the second active material layer 122 is 85%-98%.

[0075] The first electrode sheet 11 is a negative electrode sheet, the second electrode sheet 12 is a positive electrode sheet, and an insulating film 30 is provided on the first bending section 1124 of the first active material layer 112 and the second bending section 1224 of the second active material layer 122, thereby effectively reducing the risk of the first active material layer 112 and the second active material layer 122 falling off.

[0076] Combination Figure 3 As shown, the second active material layer 122 includes a second flat coating area 1221 and a second thinning area 1222. Fig.10 As shown, the second active material layer 122 includes a plurality of second straight segments 1223 and a plurality of second bent segments 1224 . Along the winding direction of the second electrode sheet 12 , the second straight segments 1223 and the second bent segments 1224 are alternately arranged, and an insulating film 30 is arranged on at least one second bent segment 1224 .

[0077] It should be noted that the positional relationship between the second pole piece 12 and the insulating film 30 is not further explained here, and the positional relationship between the first pole piece 11 and the insulating film 30 mentioned above may be referred to. For example, a plurality of insulating films 30 may be provided on the first pole piece 11 .

[0078] An embodiment of the utility model further provides a battery, comprising the above-mentioned wound battery cell.

[0079] A wound cell of a battery according to an embodiment of the utility model includes a cell body 10, a pole ear 20 and at least one insulating film 30. The first pole piece 11 of the cell body 10 includes a first current collector 111 and a first active material layer 112. By making at least one end of the first active material layer 112 include a first thinning area 1122, that is, the thickness of the first flat coating area 1121 can be greater than the first thinning area 1122, the risk of the first current collector 111 being broken during the winding process can be reduced. Along the winding direction of the first pole piece 11, the first active material layer 112 includes a plurality of first straight sections 1123 and a plurality of first bent sections 1124. By providing an insulating film 30 on at least one first bent section 1124, the risk of the first active material layer 112 falling off due to stress concentration in the first bent section 1124 during the winding process of the wound cell can be avoided, and the risk of dendrites or foreign matter piercing the first current collector 111 can be reduced. Taking into account the existence of the first thinning area 1122, by making the ratio of the height of the insulating film 30 to the height of the first active material layer 112 be 85%-98%, it is possible to avoid end warping due to weak fixing strength between the insulating film 30 and the first thinning area 1122, which may cause the insulating film 30 to fall off, thereby ensuring the safe use performance of the battery.

[0080] In one embodiment, Fig.11 As shown, the battery further includes a battery housing 50, and one or more wound battery cells may be disposed in the battery housing 50. Two pole assemblies 60 may be disposed on the battery housing 50.

[0081] The battery may be a quadrangular prism battery. A quadrangular prism battery mainly refers to a battery having a prism shape, but it is not strictly limited whether each side of the prism must be a straight line in the strict sense, and the corners between the sides are not necessarily right angles, and can be arc transitions.

[0082] An embodiment of the utility model further provides a battery pack, comprising the above-mentioned battery.

[0083] A battery pack according to an embodiment of the utility model includes a battery, wherein the wound battery cell includes a battery cell body 10, a pole ear 20 and at least one insulating film 30, and the first pole piece 11 of the battery cell body 10 includes a first current collector 111 and a first active material layer 112. By making at least one end of the first active material layer 112 include a first thinning area 1122, that is, the thickness of the first flat coating area 1121 can be greater than the first thinning area 1122, the risk of the first current collector 111 being broken during the winding process can be reduced, and along the winding direction of the first pole piece 11, the first active material layer 112 includes a plurality of first straight sections 1123 and a plurality of first bent sections 1124. By providing an insulating film 30 on at least one first bent section 1124, the risk of the first active material layer 112 falling off due to stress concentration in the first bent section 1124 during the winding process of the wound battery cell can be avoided, and the risk of dendrites or foreign matter piercing the first current collector 111 can be reduced. Taking into account the existence of the first thinning area 1122, by making the ratio of the height of the insulating film 30 to the height of the first active material layer 112 be 85%-98%, it is possible to avoid end warping due to weak fixing strength between the insulating film 30 and the first thinning area 1122, which may cause the insulating film 30 to fall off, thereby ensuring the safe use performance of the battery.

[0084] In one embodiment, the battery pack is a battery module or a battery pack.

[0085] The battery module includes a plurality of batteries, and the battery module may further include an end plate and a side plate, and the end plate and the side plate are used to fix the plurality of batteries.

[0086] It should be noted that multiple batteries can be arranged in a battery box after forming a battery module, and multiple batteries can be fixed by end plates and side plates. Multiple batteries can be directly arranged in the battery box, that is, there is no need to group multiple batteries, in which case the end plates and side plates can be removed.

[0087] Those skilled in the art will readily come up with other embodiments of the present disclosure after considering the specification and practicing the utility model disclosed herein. The present disclosure is intended to cover any variation, use or adaptation of the present utility model, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the art that are not disclosed in the present disclosure. The specification and example embodiments are to be regarded as exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

[0088] It should be understood that the present disclosure is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from its scope. The scope of protection of the present disclosure is limited only by the appended claims.

Claims

1. A wound battery cell, characterized in that: The battery cell comprises a battery cell body (10), a pole ear (20) and at least one insulating film (30), wherein the pole ear (20) extends from the battery cell body (10), and the battery cell body (10) comprises: A first pole piece (11), the first pole piece (11) comprising a first current collector (111) and a first active material layer (112), the first active material layer (112) being arranged on the first current collector (111), the first active material layer (112) comprising a first flat coating area (1121) and a first thinning area (1122), the thickness of the first flat coating area (1121) being greater than that of the first thinning area (1122), at least one end of the first active material layer (112) comprising the first thinning area (1122) in a direction in which the pole tab (20) extends from the battery cell body (10), and at least one end of the first flat coating area (1121) is connected to the first thinning area (1122); The first active material layer (112) is wound to form a plurality of first straight sections (1123) and a plurality of first bent sections (1124); along the winding direction of the first pole piece (11), the first straight sections (1123) and the first bent sections (1124) are alternately arranged; at least one of the first bent sections (1124) is provided with the insulating film (30); along the direction in which the pole ear (20) extends from the battery cell body (10), the ratio of the height of the insulating film (30) to the height of the first active material layer (112) is 85%-98%.

2. The wound battery cell according to claim 1, characterized in that: The first active material layer (112) is disposed on opposite sides of the first current collector (111); Wherein, the insulating film (30) is provided on the first bending sections (1124) on opposite sides of the first current collector (111).

3. The wound battery cell according to claim 1, characterized in that: In the direction in which the electrode tab (20) extends from the battery cell body (10), the ratio of the height of a single first thinned area (1122) to the height of the first active material layer (112) is 2%-15%.

4. The wound battery cell according to claim 1, characterized in that: In the direction in which the pole tab (20) extends from the battery cell body (10), the height of the insulating film (30) covering the first thinned area (1122) is no more than 3 mm.

5. The wound battery cell according to claim 1, characterized in that: Along the direction in which the pole tab (20) extends from the battery cell body (10), the proportion of the insulating film (30) covering the first thinned area (1122) is no greater than 40%.

6. The wound battery cell according to claim 1, characterized in that: Along the winding direction of the first pole piece (11), the size of a single insulating film (30) is 5 mm-30 mm.

7. The wound battery cell according to claim 1, characterized in that: The thickness of the first flat coating area (1121) is 60 μm-280 μm, and the ratio of the height of the insulating film (30) to the height of the first active material layer (112) is 86%-98%.

8. The wound battery cell according to claim 1, characterized in that: The insulating film (30) is bonded and fixed to the first pole piece (11), and a bonding layer (40) is provided between the insulating film (30) and the first pole piece (11); Wherein, the ratio of the thickness of the bonding layer (40) to the thickness of the first flat coating area (1121) is 0.7%-25%, and / or the thickness of the bonding layer (40) is 2 μm-15 μm.

9. The wound battery cell according to claim 1, characterized in that: From the innermost layer of the battery cell body (10) toward the outermost layer of the battery cell body (10), at least one layer on at least the first four layers of the first bending section (1124) is provided with the insulating film (30).

10. The wound battery cell according to any one of claims 1 to 9, characterized in that: The first pole piece (11) is a positive pole piece.

11. A battery, characterized in that: A wound battery cell comprising any one of claims 1 to 10.

Images