Battery cell and battery

Abstract

The battery cell comprises a battery cell body, a first pole piece, a diaphragm and a second pole piece, the first pole piece, the diaphragm and the second pole piece are sequentially stacked in the first direction, the polarity of the first pole piece is opposite to that of the second pole piece, the first pole piece comprises a first current collector and a first active layer coated on the surface of the first current collector, and the second pole piece comprises a second current collector and a second active layer coated on the surface of the second current collector. A first tab is arranged at one end of the first current collector along the second direction, the first active layer comprises a main body part and an edge part which are distributed along the second direction, the edge part is positioned at one end of the main body part facing the first tab, and the first direction is perpendicular to the second direction; the flattening assembly comprises a first adhesive part, the first adhesive part is arranged on at least one side of the battery cell body along the first direction, and the projection of the first adhesive part in the reference plane is at least partially overlapped with the projection of the edge part in the reference plane. According to the battery cell disclosed by the utility model, the compression consistency of the battery cell can be improved, and the service life of a battery is prolonged.

Description

Technical Field

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

[0002] Battery cells typically include electrodes, such as positive and negative electrodes, which are made by coating active materials onto the surface of a current collector made of metal foil. However, during the coating process, active material tailing often occurs as the coating equipment moves to the end of the current collector. This results in the finished electrode having a thinner active layer at the end than in other areas.

[0003] This will result in poor flatness in the thickness direction of the battery cell, resulting in poor pressure consistency of the battery cell. During long-term charge and discharge, black spots and lithium precipitation will appear in the battery, affecting the performance and service life of the battery. Utility Model Content

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one objective of the present invention is to provide a battery cell and battery that utilizes a first adhesive member of a flattening assembly to increase the thickness of the first active layer of the battery cell body at a corresponding position on the edge, thereby improving the flatness of the battery cell body and, in turn, the pressure consistency of the battery cell body, thereby preventing the occurrence of black speckle lithium deposition during battery cycling.

[0005] In the first aspect, the utility model proposes a battery cell, comprising: a battery cell body, comprising a first electrode piece, a diaphragm and a second electrode piece stacked in sequence along a first direction, the polarities of the first electrode piece and the second electrode piece are opposite, the first electrode piece comprises a first current collector and a first active layer coated on the surface of the first current collector, a first electrode ear is provided at one end of the first current collector along the second direction, the first active layer comprises a main body and an edge portion distributed along the second direction, the edge portion is located at one end of the main body facing the first electrode ear, the thickness of the edge portion is less than the thickness of the main body, and the first direction is perpendicular to the second direction; a flattening component, comprising a first adhesive, the first adhesive is provided on at least one side of the battery cell body along the first direction, and the projection of the first adhesive in a reference plane at least partially overlaps with the projection of the edge portion in the reference plane, and the reference plane is perpendicular to the first direction.

[0006] In the battery cell of the present invention, a first adhesive is provided on the battery cell body, and the projection of the first adhesive on the reference plane partially overlaps with the projection of the edge portion on the reference plane, that is, the first adhesive increases the thickness of the corresponding position of the edge portion in the first direction, improves the flatness of the battery cell body, thereby improving the pressure consistency of the battery cell, so that black spots and lithium precipitation will not occur during the battery cycle process, thereby extending the service life of the battery.

[0007] In some embodiments, the first electrode piece includes end electrodes located at both ends of the battery cell body along the first direction, the first active layer is coated on the surfaces of the two opposite sides of the end electrodes, and the first adhesive is attached to the side of the first current collector of the end electrode piece facing away from the first active layer, and the length H1 of the overlapping area between the first adhesive and the first current collector in the second direction is 2-20 mm.

[0008] According to some embodiments of the present invention, the diaphragm has an extension portion extending beyond the first pole piece along the second direction, the first adhesive component includes a first end facing the first pole ear along the second direction and a second end away from the first pole ear, and the projection of the first end within the reference plane is located within the projection of the extension portion within the reference plane.

[0009] In some embodiments, two ends of the first adhesive along the third direction do not exceed two ends of the battery cell body along the third direction, and the first direction, the second direction, and the third direction are perpendicular to each other.

[0010] Furthermore, a ratio between a width of the first adhesive component along the third direction and a width of the first pole piece along the third direction is 0.5-1.5.

[0011] In some embodiments, it also includes: an electrode adapter, which is welded to the first tab to form a weld; a protective adhesive, which covers the weld, and at least part of the structure of the first adhesive extends to one side surface of the battery cell body along the first direction, and the protective adhesive overlaps with at least part of the structure of the first adhesive.

[0012] In some embodiments, there are two first adhesive members, and the two first adhesive members are respectively located on two opposite surfaces of the battery cell body along the first direction, and both of them at least partially overlap with the edge portion.

[0013] In some embodiments, the flattening component further includes: a second adhesive component, wherein two second adhesive components are provided, and the two second adhesive components respectively cover the two side end surfaces of the battery cell body along the third direction, and the two ends of the second adhesive component respectively extend to the two side surfaces of the battery cell body along the first direction.

[0014] Furthermore, along the third direction, a width W1 of an overlapping area between a projection of the second adhesive component on the reference plane and a projection of the first pole piece on the reference plane is 1-10 mm.

[0015] Furthermore, one end of the second adhesive component facing the first tab along the second direction extends beyond the second pole piece along the second direction, and one end of the second adhesive component facing the first tab along the second direction is located within the projection of the diaphragm within the reference plane.

[0016] According to some embodiments of the present invention, four corners of the first pole piece and / or the second pole piece are all provided with chamfers, and the second adhesive component also partially covers the chamfers.

[0017] In some embodiments, a third adhesive is further included, the third adhesive covering the end surface of the battery cell body opposite to the first tab, and both ends of the third adhesive extending to both side surfaces of the battery cell body along the first direction.

[0018] According to an embodiment of the present invention, a length H2 of an overlapping area between a projection of the third adhesive component on the reference plane and a projection of the first pole piece on the reference plane along the second direction is 1-10 mm.

[0019] According to some embodiments of the present invention, both corners of the edge of the first pole piece and / or the second pole piece along the second direction away from the first pole ear are chamfered, and the third adhesive also covers at least part of the chamfered structure.

[0020] In some embodiments, the leveling component includes: a first adhesive component, a second adhesive component, and a third adhesive component. A gap is set between any two of the first adhesive component, the second adhesive component, and the third adhesive component, and the gap is not less than 2 mm.

[0021] In a second aspect, an embodiment of the present invention further provides a battery, comprising: an outer film shell; and the above-mentioned battery core, wherein the outer film shell covers the battery core.

[0022] The battery of the utility model uses the above-mentioned battery core, and the battery core body has good flatness and good pressure consistency. During long-term charge and discharge cycle use, black spots and lithium precipitation will not occur, and the battery has a long service life.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0025] Figure 1This is a schematic diagram of the first adhesive member, the second adhesive member, and the third adhesive member of the embodiment of the present utility model being attached to the battery cell body;

[0026] Figure 2 This is a schematic structural diagram of a battery cell according to an embodiment of the present invention at one angle, wherein a first adhesive is attached to one side surface of the battery cell body along a first direction;

[0027] Figure 3 This is a schematic structural diagram of the battery cell according to another embodiment of the present invention;

[0028] Figure 4 is a cross-sectional view of a battery cell according to some embodiments of the present invention, wherein a first adhesive is attached to a surface of one side of the battery cell body along a first direction;

[0029] Figure 5 is a cross-sectional view of a battery cell according to some embodiments of the present invention, wherein a first adhesive member is attached to both sides of the battery cell body along a first direction;

[0030] Figure 6 This is a schematic diagram of a second adhesive member of a battery cell according to an embodiment of the present invention being attached to a battery cell body;

[0031] Figure 7 This is a schematic structural diagram of the chamfered corners of a battery cell body in some embodiments of the present invention;

[0032] Figure 8 It is a structural schematic diagram of the chamfer of the battery cell body in other embodiments of the present utility model;

[0033] Figure 9 Schematic diagram of the structure of the chamfer of the battery cell body in other embodiments of the present invention;

[0034] Figure 10 Schematic diagram of the structure of the chamfer of the battery cell body in other embodiments of the present invention;

[0035] Figure 11 This is a schematic diagram of the third adhesive component of the battery cell according to an embodiment of the present invention being attached to the battery cell body.

[0036] Reference numerals:

[0037] 100-battery cells;

[0038] 110 - cell body; 111 - first pole piece; 1111 - first current collector; 1112 - first active layer; 1113 - first tab; 1114 - main body; 1115 - edge; 112 - diaphragm; 113 - second pole piece;

[0039] 120 - flattening component; 121 - first adhesive component; 122 - second adhesive component; 123 - third adhesive component;

[0040] 130-electrode adapter;

[0041] 140-Protective glue. DETAILED DESCRIPTION

[0042] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0043] For safety reasons, existing batteries are designed to have a thinner active material layer at the end of the cell's electrode with the tab than at other locations. This results in poor flatness across the thickness of the battery, leading to poor pressure consistency within the battery cells. This can lead to black specks and lithium deposition during long-term charge and discharge cycles, impacting battery performance.

[0044] In view of this, the present invention proposes a battery cell and a battery, which fills the thickness of the corresponding position of the edge of the battery cell body through the first adhesive of the flattening component, thereby improving the flatness of the battery and further improving the pressure consistency of the battery cell, so that the battery will not have black spots and lithium precipitation during the cycle process.

[0045] For the sake of convenience, the thickness direction of the battery cell can be the first direction, such as Figure 2 The Z direction shown in ; the length direction of the battery cell can be a second direction, such as Figure 2 The width direction of the cell can be a third direction, such as Figure 2 The Y direction shown; the first direction, the second direction and the third direction are perpendicular to each other.

[0046] Reference below Figures 1 to 11 , describing a battery cell 100 according to an embodiment of the first aspect of the present utility model.

[0047] refer to Figures 1 to 5 The battery cell 100 may include: a battery cell body 110 and a flattening component 120 .

[0048] The cell body 110 may include a first electrode sheet 111, a separator 112, and a second electrode sheet 113, wherein the first electrode sheet 111 and the second electrode sheet 113 have opposite polarities. For example, the first electrode sheet 111 may be a positive electrode sheet and the second electrode sheet 113 may be a negative electrode sheet, or the first electrode sheet 111 may be a negative electrode sheet and the second electrode sheet 113 may be a positive electrode sheet. The cell body 110 may be structured such that the first electrode sheet 111, the separator 112, and the second electrode sheet 113 are stacked in sequence along a first direction, thereby forming a laminated cell 100. Of course, the cell body 110 may also be a wound cell 100 formed by stacking and winding the first electrode sheet 111, the separator 112, and the second electrode sheet 113.

[0049] The first electrode sheet 111 may include a first current collector 1111 and a first active layer 1112 coated on the surface of the first current collector 1111. The first electrode sheet 111 is a positive electrode sheet, and the first current collector 1111 is a positive electrode current collector. The positive electrode current collector is usually made of aluminum foil and is used to support the first active layer 1112. The first active layer 1112 is a positive electrode active layer and is mainly composed of a lithium compound (such as lithium cobalt oxide, lithium iron phosphate, etc.). The positive electrode active layer inserts and extracts lithium ions during the charge and discharge process of the battery, thereby achieving energy storage and release. Similarly, the second electrode sheet 113 may include a second current collector and a second active layer coated on the surface of the second current collector. The second electrode sheet 113 is a negative electrode sheet, and the second current collector is a negative electrode current collector. The negative electrode current collector is usually made of copper foil and is used to support the second active layer. The second active layer is a negative electrode active layer and is mainly composed of a carbon material (such as graphene). The negative electrode active layer inserts and extracts lithium ions during the charge and discharge process of the battery, thereby achieving energy storage and release.

[0050] The first current collector 1111 is provided with a first electrode tab 1113 at one end along the second direction. The first electrode tab 1113 is a positive electrode tab. The second current collector is provided with a second electrode tab at one end along the second direction. The second electrode tab is a negative electrode tab. The first electrode tab 1113 and the second electrode tab are staggered along the third direction. The first active layer 1112 and the second active layer include a main body 1114 and an edge portion 1115 distributed along the second direction. The edge portion 1115 is located at the end of the main body 1114 facing the first electrode tab 1113 and the second electrode tab. In other words, along the second direction, the edge portion 1115 is located at the end of the cell body 110 where the first electrode tab 1113 and the second electrode tab are provided. Since the first active layer 1112 is prone to tailing at the end of the first current collector 1111 during the process of coating the first active layer 1112 onto the first current collector 1111, resulting in the thickness of the tailing area being smaller than the thickness of other areas, the active layer formed in the tailing area is the edge portion 1115, that is, the thickness of the edge portion 1115 is smaller than the thickness of the main body 1114.

[0051] The leveling component 120 may include a first adhesive 121, which is provided on at least one side of the cell body 110 along the first direction, that is, the first adhesive 121 may be attached to one side of the cell body 110 along the first direction, or the first adhesive 121 may be attached to both sides of the cell body 110 along the first direction. Figure 1 In the XY plane shown in FIG, the projection of the first adhesive 121 at least partially overlaps with the projection of the edge portion 1115, that is, the first adhesive 121 is parallel to the edge portion 1115 in the first direction. In this way, the thickness of the battery cell body 110 at the corresponding position of the edge portion 1115 is increased by the first adhesive 121, thereby improving the thickness consistency of each area of ​​the battery cell body 110.

[0052] In the battery cell 100 of the present invention, the first active layer 1112 has an edge portion 1115 at one end near the first electrode tab 1113. By providing a first adhesive 121 that overlaps with the edge portion 1115 on at least one side surface of the battery cell body 110 along the first direction, the thickness of the first adhesive 121 can be used to compensate for the thickness difference between the edge portion 1115 and the main body 1114, thereby increasing the thickness of the battery cell body 110 in the area corresponding to the edge portion 1115, thereby improving the thickness uniformity of various areas of the battery cell body 110. In this way, the pressure consistency of various areas of the battery cell body 110 during operation can be ensured, thereby extending the service life of the battery cell 100 and reducing cycle black spots and lithium plating during the cycle process.

[0053] refer to Figure 2 、 Figure 3 and Figure 4 In some embodiments, the first electrode 111 includes end electrodes located at both ends of the battery cell body 110 along the first direction, and the surfaces of the two opposite sides of the two end electrodes are coated with the first active layer 1112. The surfaces of both sides of the first electrode 111 located between the two end electrodes along the first direction are coated with the first active layer 1112 to facilitate charged particle exchange reaction with the second electrode 113.

[0054] The first adhesive 121 is affixed to the side of the first current collector 1111 of the end electrode facing away from the first active layer 1112, that is, the first current collector 1111 of the outermost first electrode 111 of the battery cell 100 is coated with the first active layer 1112 only on the side of the second electrode 113 facing the battery cell body 110, and the first adhesive 121 is affixed to the side of the first current collector 1111 facing away from the first active layer 1112 (the side facing outside the battery cell body 110). The length H1 of the overlapping area between the first adhesive 121 and the first current collector 1111 in the second direction is 2-20 mm. In other words, the length H1 of the overlapping area between the first adhesive 121 and the edge portion 1115 along the second direction is 2-20 mm. For example, H1 may be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, or 20 mm. Preferably, the length H1 may be 5-10 mm.

[0055] On the one hand, the coverage area of ​​the first adhesive 121 should be avoided to be too small (e.g., less than 2 mm), which would leave an uncovered area between the edge portion 1115 and the main body 1114, thus poorly improving the flatness of the cell body 110. On the other hand, the coverage area of ​​the first adhesive 121 should be avoided to be too large (e.g., exceeding 20 mm). In this case, the first adhesive may overlap with the main body 1114, and the overlapping portion of the first adhesive 121 with the main body 1114 would protrude from the surface of the cell body 110, thereby reducing the flatness of the cell body 110 and affecting normal battery operation. The length of the first adhesive 121 and the edge portion 1115 along the second direction is matched, thereby improving the flatness of the end surface of the cell body 110 in the thickness direction. Of course, the length H1 of the overlapping area of ​​the first adhesive 121 and the first current collector 1111 in the second direction can also be other values. Designers can select according to their needs, and this embodiment does not limit this.

[0056] refer to Figure 5 In some embodiments, there may be two first adhesive members 121, each located on opposite sides of the cell body 110 along a first direction (thickness direction), and both at least partially overlapping the edge portion 1115. Thus, the first adhesive members 121 attached to both sides of the cell body 110 in the thickness direction increase the thickness of the cell body 110 at the edge portion 1115, making the thickness of the cell body 110 more uniform across both sides. This improves the compressive consistency of the cell 100, thereby extending the battery life.

[0057] refer to Figure 2 、 Figure 4 and Figure 5In some embodiments, the battery cell 100 may further include an electrode adapter 130 and a protective adhesive 140 .

[0058] The electrode adapter 130 is a transitional component that allows the battery cell body 110 to be connected to an external electrical device. Two electrode adapters 130 may be provided, one welded to the first and second tabs, forming welds on the first and second tabs. The protective adhesive 140, which may be adhesive tape or an insulating adhesive coating, covers the welds and the first and second tabs. At least a portion of the first adhesive 121 (the first end, described below) extends to one side of the battery cell body 110 along the first direction (the surface where the first tab 1113 is located), with the protective adhesive 140 overlapping this portion of the first adhesive 121. The first adhesive 121 secures the protective adhesive 140, enhancing the protection of the first and second tabs and preventing the first tab 1113 from being inserted backwards into the first electrode sheet 111 during a drop test, thereby improving battery safety.

[0059] Continue to refer Figure 3 According to some embodiments of the present invention, the diaphragm 112 has an extension portion extending beyond the first electrode piece 111 along the second direction, so as to ensure that the diaphragm 112 physically separates the first electrode piece 111 and the second electrode piece 113, thereby avoiding direct contact between the first electrode piece 111 and the second electrode piece 113 and causing an internal short circuit in the battery.

[0060] Along the second direction, the first adhesive 121 includes a first end facing the first tab 1113 and a second end away from the first tab 1113. The first end is on the reference surface (eg Figure 1 The projection in the XY plane shown in the figure is located within the projection of the extension portion in the reference plane, that is, the edge of the first end along the second direction does not exceed the outer edge of the diaphragm 112. In this way, the first end of the first adhesive 121 is prevented from extending to the weld position, which affects the welding process of the electrode adapter 130 and the first tab 1113 and the second tab, thereby improving the safety of the battery.

[0061] refer to Figures 1 to 3 In some embodiments, the two ends of the first adhesive 121 along the third direction do not exceed the two ends of the battery cell body 110 along the third direction. In other words, along the width direction of the battery cell body 110, the width of the first adhesive 121 does not exceed the width of the battery cell body 110, so that the two ends of the first adhesive 121 along the third direction do not exceed the two side end surfaces of the battery cell body 110 in the width direction. In this way, when the battery cell 100 is packaged in the outer film shell of the battery, the first adhesive 121 will not be packaged, thereby improving the reliability of the battery packaging process.

[0062] Continue to refer Figure 3 Furthermore, along the third direction, the ratio of the width of the first adhesive 121 to the width of the first electrode piece 111 is 0.5-1.5. For example, the ratio of the width of the first adhesive 121 to the width of the first electrode piece 111 can be 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, or 1.5. On the one hand, it is preferable to avoid the ratio of the width of the first adhesive 121 to the width of the first electrode piece 111 being too small (for example, less than 0.5), which results in poor thickness compensation effect in the area where the edge portion 1115 is located, and fails to improve the flatness of the battery cell body 110. On the other hand, it is preferable to avoid the ratio of the width of the first adhesive 121 to the width of the first electrode piece 111 being too large (for example, exceeding 1.5), which results in the ends of the first adhesive 121 along the third direction extending beyond the two side end surfaces of the width direction of the battery cell body 110, affecting the packaging effect. In this way, the first adhesive 121 can fill the thickness of the edge portion 1115 of the cell body 110, improving the flatness of the cell body 110. Of course, the ratio of the width of the first adhesive 121 to the width of the first electrode 111 can also be other values, which can be selected by designers according to their needs, and this embodiment does not impose any restrictions on this.

[0063] refer to Figure 1 and Figure 6 In some embodiments, the flattening component 120 may further include a second adhesive 122, and the second adhesive 122 is provided in two pieces. The two second adhesives 122 respectively cover the two side end surfaces of the battery cell body 110 along the third direction, and the two ends of the second adhesive 122 respectively extend to the two side surfaces of the battery cell body 110 along the first direction.

[0064] In other words, the two second adhesives 122 respectively cover the two side end faces of the battery cell body 110 along the width direction, and the two ends of the second adhesive 122 respectively extend to the two side surfaces of the battery cell body 110 along the thickness direction, that is, the two second adhesives 122 are formed into a U-shaped structure, covering the two ends of the outermost first pole piece 111 of the battery cell body 110 along the width direction, thereby improving the adhesion effect between the first pole piece 111 and the diaphragm 112, and avoiding the warping of the two ends of the width direction of the first pole piece 111. In this way, the structural stability of the battery cell body 110 is improved, thereby improving the drop performance of the battery cell body 110 and improving the safety of the battery.

[0065] Continue to refer Figure 6According to some embodiments of the present invention, along the third direction, the width W1 of the overlapping area between the projection of the second adhesive 122 on the reference plane and the projection of the first electrode piece 111 on the reference plane is 2-10 mm. In other words, one end of the second adhesive 122 extends to cover the first electrode piece 111 on one side of the thickness direction of the battery cell body 110. Along the third direction, the width W1 of the second adhesive 122 covering the first electrode piece 111 can be 1-10 mm. For example, W1 can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm. The preferred value of W1 can be 4-6 mm.

[0066] On the one hand, the width W1 of the second adhesive 122 covering the first electrode piece 111 is prevented from being too small (e.g., less than 1 mm), resulting in poor adhesion between the second adhesive 122 and the battery cell body 110, making the second adhesive 122 easy to fall off. On the other hand, the width W1 of the second adhesive 122 covering the first electrode piece 111 is prevented from being too large (e.g., exceeding 10 mm), overlapping with the main body 1114, resulting in the flatness of the end surfaces on both sides of the battery cell body 110 in the thickness direction being deteriorated. By providing the second adhesive 122, the fixing effect on both ends of the battery cell body 110 in the thickness direction is improved, and the problem of uneven force on the edge of the battery cell body 110 caused by the different sizes of the first electrode piece 111 and the second piece needing to be staggered is improved, thereby improving the force consistency of the battery cell body 110. Of course, the width of the second adhesive 122 covering the first electrode piece 111 can also be other values, and designers can choose according to their needs. This is not limited in this embodiment.

[0067] According to some embodiments of the present invention, the four corners of the first pole piece 111 and the second pole piece 113 are provided with chamfers, such as Figures 7 to 10 As shown, the chamfered corners of the first electrode 111 and the second electrode 113 can be structured as follows: one R angle is connected to an oblique line instead of a right angle; or, two R angles are respectively connected to two right-angled sides, and the two R angles are connected by an oblique line to replace a right angle; or, two right-angled sides are directly connected by an oblique line to replace a right angle; or, a right angle can be directly replaced by an R angle. The range of the chamfered R angle can be between 1.0-3.0 mm, for example, the chamfered R angle can be 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm or 3 mm. In this way, the battery is prevented from being squeezed by the electrode during use, causing the outer shell membrane of the battery to rupture, resulting in battery leakage, thereby improving the safety of the battery. Of course, the chamfered R angle can also be other values, and designers can choose according to their needs. This embodiment does not limit this.

[0068] The two second adhesives 122 partially cover the two chamfers on both sides of the first electrode 111 or the second electrode 113 along the width direction at both ends along the second direction, further improving the binding effect on the two ends of the battery cell body 110 along the width and improving the force consistency of the battery cell body 110.

[0069] Continue to refer Figure 6 According to some embodiments of the present invention, one end of the second adhesive 122 facing the first electrode tab 1113 along the second direction extends beyond the edge of the second electrode sheet 113 along the second direction, and the other end of the second adhesive 122 facing the first electrode tab 1113 along the second direction is located within the projection of the separator 112 on the reference plane. In other words, along the second direction, the edge of the second adhesive 122 is located between the edge of the second electrode sheet 113 and the edge of the separator 112. The second electrode sheet 113 is a negative electrode sheet, and for safety reasons, the size of the negative electrode sheet is larger than that of the positive electrode sheet. As such, the second adhesive 122 can cover the two chamfered corners on one side of the width direction of the first electrode sheet 111 or the second electrode sheet 113, thereby improving the covering effect on the battery cell body 110 and thereby achieving higher consistency in the force applied to the battery cell body 110.

[0070] refer to Figure 1 and Figure 11 In some embodiments, the flattening component 120 may further include: a third adhesive 123, the third adhesive 123 covers the end surface of the battery cell body 110 opposite to the first tab 1113, and the two ends of the third adhesive 123 extend to the two side surfaces of the battery cell body 110 along the first direction respectively.

[0071] In other words, the third adhesive 123 covers the end face of the battery cell body 110 in the second direction (length direction) away from the first pole ear 1113, and the two ends of the third adhesive 123 extend to the two side surfaces of the battery cell body 110 in the thickness direction, that is, the third adhesive 123 is formed into a U-shaped structure, covering the end face of the battery cell body 110 in the length direction away from the first pole ear 1113, and partially overlapping with the two side faces of the battery cell body 110 in the thickness direction.

[0072] The third adhesive 123 improves the adhesion between the first electrode piece 111 and the diaphragm 112, thereby preventing the outermost first electrode piece 111 of the battery cell body 110 from warping at the end away from the first electrode tab 1113, thereby improving the structural stability of the battery cell body 110, thereby improving the drop performance of the battery cell body 110 and making the battery safer.

[0073] Continue to refer Figure 11In some embodiments, the length H2 of the overlapping area between the projection of the third adhesive 123 on the reference plane and the projection of the first electrode piece 111 on the reference plane along the second direction is 1-10 mm. In other words, one end of the third adhesive 123 extends to cover the first electrode piece 111 on one side of the thickness direction of the battery cell body 110. Along the third direction, the width H2 of the third adhesive 123 covering the first electrode piece 111 can be 2-10 mm. For example, H2 can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm. The preferred value of H2 can be 4-6 mm.

[0074] On the one hand, the width H2 of the third adhesive 123 covering the first electrode sheet 111 is prevented from being too small (e.g., less than 1 mm), resulting in poor adhesion between the third adhesive 123 and the cell body 110 and making the third adhesive 123 easily fall off. On the other hand, the width H2 of the third adhesive 123 covering the first electrode sheet 111 is prevented from being too large (e.g., exceeding 10 mm), overlapping with the main body 1114, and thereby deteriorating the flatness of the end surfaces of the cell body 110 in the thickness direction. The provision of the third adhesive 123 effectively secures the end of the cell body 110 away from the first electrode tab 1113 along the length direction, thereby improving the uneven force applied to the edges of the cell body 110 due to the different sizes of the first and second electrode sheets 111 and the need for offset placement, thereby improving the force consistency of the cell body 110. Of course, the width of the third adhesive 123 covering the first electrode sheet 111 can also be other values, which can be selected by the designer according to their needs and are not limited in this embodiment.

[0075] According to some embodiments of the present invention, both ends of the third adhesive 123 along the third direction extend along the third direction, overlapping with the chamfered portion of the end of the first electrode sheet 111 away from the first electrode tab 1113 (or the end of the second electrode sheet 113 away from the second electrode tab). Both ends of the third adhesive 123 along the third direction also cover this portion. This improves the restraint effect of the third adhesive 123 on the cell body 110, thereby improving the force consistency of the cell body 110.

[0076] refer to Figure 1In some embodiments, the first adhesive 121, the second adhesive 122, and the third adhesive 123 of the flattening assembly 120 can be used individually or in combination. When used in combination, a gap is provided between any two of the first adhesive 121, the second adhesive 122, and the third adhesive 123, and each gap is no less than 2 mm. For example, the first adhesive 121 may have gaps with the two second adhesives 122 at both ends along the third direction, or the third adhesive 123 may have gaps with the two second adhesives 122 at both ends along the third direction. This facilitates the entry of electrolyte into the cell body 110 during packaging, thereby increasing the energy density of the cell body 110. Furthermore, it also makes the force applied to the four sides of the cell body 110 perpendicular to the XY plane more uniform, thereby improving the force consistency of the cell body 110 and extending the battery life.

[0077] In a second aspect, an embodiment of the present invention further provides a battery, which may be a lithium-ion battery, a sodium-ion battery, or other types of batteries.

[0078] The battery may include an outer film shell and the aforementioned battery cell 100, wherein the outer film shell encapsulates the battery cell 100. Due to the use of the aforementioned battery cell 100, the battery cell body 110 of the present invention has good flatness and good pressure consistency of the battery cell 100. During long-term charge and discharge cycles, black spots and lithium precipitation will not occur, thereby extending the battery life.

[0079] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0080] In the description of the present invention, "first feature" and "second feature" may include one or more such features.

[0081] In the description of the present invention, “plurality” means two or more.

[0082] In the description of the present invention, a first feature being “above” or “below” a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact via another feature therebetween.

[0083] In the description of the present invention, a first feature “above”, “above” and “above” a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0084] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative use of the above terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0085] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and purpose of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery cell (100), characterized in that: include: A cell body (110) comprises a first pole piece (111), a diaphragm (112) and a second pole piece (113) stacked in sequence along a first direction, wherein the first pole piece (111) and the second pole piece (113) have opposite polarities, the first pole piece (111) comprises a first current collector (1111) and a first active layer (1112) coated on the surface of the first current collector (1111), a first pole lug (1113) is provided at one end of the first current collector (1111) along a second direction, the first active layer (1112) comprises a main body (1114) and an edge portion (1115) distributed along the second direction, the edge portion (1115) is located at one end of the main body (1114) facing the first pole lug (1113), the thickness of the edge portion (1115) is less than the thickness of the main body (1114), and the first direction is perpendicular to the second direction; A flattening component (120) includes a first adhesive component (121), wherein the first adhesive component (121) is provided on at least one side of the battery cell body (110) along the first direction, and a projection of the first adhesive component (121) in a reference plane at least partially overlaps with a projection of the edge portion (1115) in the reference plane, and the reference plane is perpendicular to the first direction.

2. The battery cell (100) according to claim 1, characterized in that The first pole piece (111) comprises end pole pieces located at both ends of the battery cell body (110) along the first direction, and the first active layer (1112) is coated on opposite sides of the two end pole pieces. The first adhesive (121) is attached to the side of the first current collector (1111) of the end electrode that faces away from the first active layer (1112). The length H1 of the overlapping area between the first adhesive (121) and the first current collector (1111) in the second direction is 2-20 mm.

3. The battery cell (100) according to claim 2, characterized in that The diaphragm (112) has an extension portion extending beyond the first pole piece (111) along the second direction, The first adhesive component (121) includes a first end facing the first tab (1113) along the second direction and a second end away from the first tab (1113), and a projection of the first end within the reference plane is located within a projection of the extension within the reference plane.

4. The battery cell (100) according to claim 1, characterized in that The two ends of the first adhesive (121) along the third direction do not exceed the two ends of the battery cell body (110) along the third direction, and the first direction, the second direction and the third direction are perpendicular to each other.

5. The battery cell (100) according to claim 4, characterized in that: The ratio between the width of the first adhesive component (121) along the third direction and the width of the first pole piece (111) along the third direction is 0.5-1.

5.

6. The battery cell (100) according to claim 1, characterized in that Also includes: An electrode adapter (130), wherein the electrode adapter (130) is welded to the first electrode tab (1113) to form a weld; A protective adhesive (140) covers the weld, at least a portion of the structure of the first adhesive component (121) extends to one side surface of the battery cell body (110) along the first direction, and the protective adhesive (140) overlaps with at least a portion of the structure of the first adhesive component (121).

7. The battery cell (100) according to claim 1, characterized in that There are two first adhesive parts (121), and the two first adhesive parts (121) are respectively located on two opposite surfaces of the battery cell body (110) along the first direction, and both at least partially overlap with the edge portion (1115).

8. The battery cell (100) according to any one of claims 1 to 7, characterized in that: The flattening component (120) further includes: a second adhesive component (122), wherein two second adhesive components (122) are provided, and the two second adhesive components (122) respectively cover the two side end surfaces of the battery cell body (110) along the third direction, and the two ends of the second adhesive component (122) respectively extend to the two side surfaces of the battery cell body (110) along the first direction.

9. The battery cell (100) according to claim 8, characterized in that: Along the third direction, a width W1 of an overlapping area between a projection of the second adhesive member (122) on the reference plane and a projection of the first pole piece (111) on the reference plane is 1-10 mm.

10. The battery cell (100) according to claim 9, characterized in that: One end of the second adhesive component (122) facing the first pole tab (1113) along the second direction extends beyond the second pole piece (113) along the second direction, and one end of the second adhesive component (122) facing the first pole tab (1113) along the second direction is located within the projection of the diaphragm (112) within the reference plane.

11. The battery cell (100) according to claim 8, characterized in that: The four corners of the first pole piece (111) and / or the second pole piece (113) are all provided with chamfers, and the second adhesive component (122) also partially covers the chamfers.

12. The battery cell (100) according to any one of claims 1 to 7, characterized in that: The battery cell body (110) further includes a third adhesive (123), the third adhesive (123) covering the end surface of the battery cell body (110) opposite to the first pole ear (1113), and the two ends of the third adhesive (123) respectively extend to the two side surfaces of the battery cell body (110) along the first direction.

13. The battery cell (100) according to claim 12, characterized in that: The length H2 of the overlapping area between the projection of the third adhesive component (123) on the reference plane and the projection of the first pole piece (111) on the reference plane along the second direction is 1-10 mm.

14. The battery cell (100) according to claim 12, characterized in that: Both corners of the edge of the first pole piece (111) and / or the second pole piece (113) along the second direction away from the first pole tab (1113) are chamfered. The third adhesive component (123) also covers at least a portion of the chamfered structure.

15. The battery cell (100) according to any one of claims 1 to 7, characterized in that: The leveling component (120) comprises: a first adhesive component (121), a second adhesive component (122) and a third adhesive component (123); a gap is set between any two of the first adhesive component (121), the second adhesive component (122) and the third adhesive component (123), and the gap is not less than 2 mm.

16. A battery, characterized in that: include: outer membrane shell; The battery core (100) according to any one of claims 1 to 15, wherein the outer film shell covers the battery core (100).

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