Battery cell, battery and electric equipment

Abstract

The utility model discloses a battery cell, a battery and electric equipment, and relates to the technical field of new energy. The battery cell comprises a diaphragm, a plurality of positive plates and a plurality of negative plates, the plurality of positive plates and the plurality of negative plates are alternately laminated to form a laminated battery cell, and the adjacent positive plates and negative plates are separated by the diaphragm; wherein the corner position of each positive plate is provided with a first cut corner, the corner position of each negative plate is provided with a second cut corner, the battery cell is provided with a first end and a second end which are opposite to each other along the thickness direction of the battery cell, the areas of the adjacent first cut corners are gradually reduced along the direction from the first end to the second end, and the areas of the adjacent second cut corners are gradually reduced along the direction from the first end to the second end. And the first cut corner and the second cut corner are correspondingly communicated so as to form a cut-off structure at the corner position of the battery cell. According to the battery cell disclosed by the invention, the cutting structures are formed at the corners, so that an arc transition section of the aluminum plastic film is avoided, the distance between the battery cell and the aluminum plastic film at the corners is increased, and the problems of scratching, deformation and the like of the pole pieces are avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to new energy technology field especially, it relates to a kind of electric core, battery and electric equipment. BACKGROUND

[0002] In recent years, with the rapid development of electronic communication technology, the battery that provides power also develops rapidly. Lithium-ion battery has the advantages of high voltage, large specific energy, long cycle life, good safety performance, etc., and is favored by many users.

[0003] In the packaging process of lithium-ion battery, pits are often punched on the aluminum plastic film to form a containing cavity for accommodating the electric core. If the gap between the electric core and the aluminum plastic film is too small, there is a risk of scratching or extruding the pole piece during the packaging process of the battery. If the gap between the electric core and the aluminum plastic film is too large, it will affect the energy density of the battery. It should be noted that, in order to avoid stress concentration, the four corner positions of the containing cavity often use a round corner transition. Therefore, when the electric core is placed in the containing cavity, the distance between the corner position of the electric core and the aluminum plastic film is closer than other positions, and the situation of scratching or extruding the pole piece is more likely to occur. SUMMARY

[0004] The utility model aims at at least one of the technical problems existing in the prior art. Therefore, the utility model provides an electric core. By forming a cutout structure at the corner position, the arc transition section of the aluminum plastic film is avoided, the distance between the electric core and the aluminum plastic film at the corner position is increased, and the problems of pole piece scratching and deformation are avoided.

[0005] The utility model also provides another electric core.

[0006] The utility model also provides a battery with the above-mentioned electric core.

[0007] The utility model also provides an electric device with the above-mentioned battery.

[0008] According to the electric core of the first aspect embodiment of the utility model, the electric core includes a diaphragm, a plurality of positive pole pieces and a plurality of negative pole pieces. The plurality of positive pole pieces and the plurality of negative pole pieces are alternately stacked to form a laminated core. Adjacent positive pole pieces and negative pole pieces are separated by the diaphragm.

[0009] Among them, the corner position of each positive pole piece is provided with a first cut corner, and the corner position of the negative pole piece is provided with a second cut corner. The electric core has opposite first and second ends along its thickness direction. Along the direction from the first end to the second end, the area of adjacent first cut corners gradually decreases, and the area of adjacent second cut corners gradually decreases. The first cut corner and the second cut corner correspond to communication to form a cutout structure at the corner position of the electric core.

[0010] According to the battery cell provided by the embodiment of the present application, the following beneficial effects are achieved:

[0011] The battery cell provided by the present application forms a cutout structure at the corner position, thereby avoiding the arc transition section of the aluminum plastic film, increasing the spacing between the battery cell and the aluminum plastic film at the corner position, avoiding problems such as scratching and deformation of the pole piece, and enabling the spacing between the battery cell and the aluminum plastic film at the side position to be small, thereby facilitating improvement of the energy density of the battery cell. In addition, the cutout structure is designed in a targeted manner in view of the structure in which the top of the accommodating cavity is wide and the bottom is narrow, and the size of the cutout structure gradually decreases in a direction away from the bottom of the accommodating cavity, thereby further reducing the influence of the cut corner on the energy density of the battery cell.

[0012] According to some embodiments of the present application, in a direction from the first end to the second end, the size of the positive pole piece gradually increases, and the size of the negative pole piece gradually increases.

[0013] According to some embodiments of the present application, the positive pole piece includes a positive current collector and a positive active layer, and the negative pole piece includes a negative current collector and a negative active layer, and in the adjacent positive active layer and negative active layer, in a projection from the first end to the second end, the projection area of the positive active layer falls within the projection area of the negative active layer.

[0014] According to some embodiments of the present application, the negative pole piece includes a negative double-sided pole piece, and in the negative double-sided pole piece, the negative current collector is coated with the negative active layer on two surfaces in the thickness direction of the negative current collector, and the sizes of the negative active layers on the two surfaces are the same or different.

[0015] And / or, the positive pole piece includes a positive double-sided pole piece, and in the positive double-sided pole piece, the positive current collector is coated with the positive active layer on two surfaces in the thickness direction of the positive current collector, and the sizes of the positive active layers on the two surfaces are the same or different.

[0016] According to some embodiments of the present application, the corner position of the positive pole piece forms the first cut corner through chamfering, the first cut corner R1 is 0.5mm to 4mm, and / or the corner position of the negative pole piece forms the second cut corner through chamfering, the second cut corner R2 is 0.5mm to 4mm.

[0017] According to some embodiments of the present application, in any two adjacent negative pole pieces, the negative pole piece close to the first end is defined as a first negative pole piece, and the negative pole piece close to the second end is defined as a second negative pole piece, and the cut corner area of the first negative pole piece is 1.03 to 1.3 times the cut corner area of the second negative pole piece.

[0018] And / or, in any two adjacent positive electrode sheets, the positive electrode sheet close to the first end is set as a first positive electrode sheet, and the positive electrode sheet close to the second end is set as a second positive electrode sheet, the cutting angle area of the first positive electrode sheet is 1.03 to 1.3 times of the cutting angle area of the second positive electrode sheet.

[0019] The electric core according to the second aspect of the present application, the electric core comprises a diaphragm, a positive electrode sheet and a negative electrode sheet, the positive electrode sheet, the diaphragm and the negative electrode sheet are wound to form a wound electric core, adjacent positive electrode sheets and negative electrode sheets are separated by the diaphragm;

[0020] Wherein, the two side edges of the positive electrode sheet are respectively provided with a plurality of first cutting angles arranged along the length direction thereof, the two side edges of the negative electrode sheet are respectively provided with a plurality of second cutting angles arranged along the length direction thereof, the first cutting angles and the second cutting angles are correspondingly arranged, the electric core has opposite first end and second end along the thickness direction thereof, along the direction from the first end to the second end, the area of the first cutting angle of adjacent coil layers gradually decreases, the area of the second cutting angle of adjacent coil layers gradually decreases, each first cutting angle and second cutting angle correspondingly communicate to form a cutting structure at the corner position of the electric core.

[0021] According to some embodiments of the present application, the positive electrode sheet comprises a positive electrode current collector and a positive electrode active layer, the negative electrode sheet comprises a negative electrode current collector and a negative electrode active layer, the width of the negative electrode active layer is greater than the width of the positive electrode active layer.

[0022] According to some embodiments of the present application, the first cutting angle is any one of arc shape, polygon, and / or the second cutting angle is any one of arc shape, polygon, the shapes of the first cutting angle and the second cutting angle connected to each other are the same.

[0023] According to some embodiments of the present application, the area of the cutting structure at the first end is 1.8 to 2 times of the area of the cutting structure at the second end.

[0024] The battery according to the third aspect of the present application comprises:

[0025] An aluminum plastic film, the aluminum plastic film defines a containing cavity;

[0026] The electric core according to any one of the above embodiments, the first end of the electric core is placed at the bottom of the containing cavity.

[0027] According to some embodiments of the present application, at the first end of the electric core, the distance from the edge of the cutting structure of the electric core to the side wall of the containing cavity is 1.8mm to 2.8mm;

[0028] And / or, at the second end of the electric core, the distance from the edge of the cutout structure of the electric core to the side wall of the accommodating cavity is 3.5mm to 4.5mm.

[0029] According to some embodiments of the present application, the accommodating cavity comprises four side walls and a bottom wall, adjacent side walls are circularly arc transitioned, and the distance between opposite side walls gradually increases in the direction away from the bottom wall.

[0030] The power equipment according to the fourth aspect of the present application comprises the battery mentioned in any of the above embodiments.

[0031] Additional aspects and advantages of the present application will be given in part in the following description, some will become apparent from the following description, or will be understood by those skilled in the art through practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0032] The present application will be further described below in combination with the drawings and embodiments, wherein:

[0033] Figure 1 It is a magnified schematic view of the electric core placed at the corner position in the aluminum plastic film in the related art;

[0034] Figure 2 It is a schematic view of a plurality of first cut angles on the positive plate according to an embodiment of the present application;

[0035] Figure 3 It is a structural schematic view of the stacked electric core according to an embodiment of the present application (viewed from the first end to the second end, the cut angle is arc-shaped);

[0036] Figure 4 It is a structural schematic view of the stacked electric core according to an embodiment of the present application (viewed from the first end to the second end, the cut angle is rectangular);

[0037] Figure 5 It is a cross-sectional schematic view of the stacked electric core according to an embodiment of the present application;

[0038] Figure 6 It is a cross-sectional schematic view of the stacked electric core according to another embodiment of the present application;

[0039] Figure 7 It is a structural schematic view of the wound electric core according to an embodiment of the present application;

[0040] Figure 8 It is an unfolded schematic view of the positive plate according to an embodiment of the present application;

[0041] Figure 9 It is a structural schematic view of the battery according to an embodiment of the present application.

[0042] REFERENCE NUMERALS:

[0043] Battery cell 10; cutout structure 11; first end 12; second end 13; aluminum plastic film 20; accommodating cavity 21;

[0044] Positive plate 100; positive current collector 110; positive active layer 120; first cut corner 130;

[0045] Negative plate 200; negative current collector 210; negative active layer 220; DETAILED DESCRIPTION

[0046] The embodiments of the present application are described in detail below, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary only, and are used only for explaining the present application, and cannot be understood as a limitation of the present application.

[0047] In the description of the present application, it is understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as a limitation of the present application.

[0048] In the description of the present application, the meaning of several is more than one, the meaning of multiple is more than two, greater than, less than, more than, etc. are understood as not including the number, above, below, etc. are understood as including the number. If the first, second is described, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implying the number of the indicated technical features or the order of the indicated technical features.

[0049] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical scheme.

[0050] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0051] In the packaging process of a lithium ion battery, a pocket is often punched on an aluminum plastic film to form a receiving cavity 21 for accommodating a battery cell. If the gap between the battery cell and the aluminum plastic film is too small, there is a risk of scratching or extruding the pole piece during the packaging process of the battery. If the gap between the battery cell and the aluminum plastic film is too large, the energy density of the battery will be affected. It should be noted that, in order to avoid stress concentration, the four corner positions of the receiving cavity 21 often adopt a round corner transition. Therefore, as shown in Figure 1 , the edge corner position of the battery cell is closer to the aluminum plastic film than other positions, and the situation of scratching or extruding the pole piece is more likely to occur.

[0052] To solve the above problems, the first aspect of the present application provides a battery cell 10, as shown in Figures 3 to 6 , the battery cell includes a diaphragm (not shown in the figure), a plurality of positive pole pieces 100 and a plurality of negative pole pieces 200, and the plurality of positive pole pieces 100 and the plurality of negative pole pieces 200 are alternately stacked to form a pole piece battery. It should be explained that the battery cell 10 can include an entire diaphragm strip, and the adjacent positive pole pieces 100 and negative pole pieces 200 are separated in turn by Z-shaped pole pieces. Alternatively, the battery cell 10 can also include a plurality of separate diaphragms, and a diaphragm is placed between each positive pole piece 100 and negative pole piece 200 when the positive pole piece 100 and negative pole piece 200 are stacked, thereby separating the adjacent positive pole piece 100 and negative pole piece 200.

[0053] Taking the positive pole piece 100 as an example, the positive pole piece 100 is of a rectangular structure, including four straight edges connected end to end in turn, and adjacent straight edges define sharp right angles, and the right angle is the edge corner position of the positive pole piece 100. Therefore, the positive pole piece 100 and the negative pole piece 200 each have four edge corner positions. As shown in the positive pole piece 100 as an example shown in Figure 1 , since the four corner positions of the receiving cavity 21 adopt a round corner transition, the sharp corners at the edge corner positions of the positive pole piece 100 may, on the one hand, cause the gap between the pole piece and the aluminum plastic film 20 to be too small, resulting in scratching, and on the other hand, the sharp corners of the pole piece may pierce the aluminum plastic film 20. Therefore, a first chamfer 130 is provided at each edge corner position of each positive pole piece 100 (as shown in Figure 2 ), and a second chamfer (not shown in the figure) is provided at each edge corner position of each negative pole piece 200, thereby removing the sharp right angles on the pole piece and increasing the gap between the pole piece and the aluminum plastic film 20 at the original edge corner position.

[0054] As shown in the embodiment shown in Figure 2 , the first chamfer 130 can be arc-shaped, and further, the arc-shaped can be outward convex as shown in Figure 2 a of the figure, or can be inward concave as shown in Figure 2 c of the figure. The first chamfer 130 can also be as shown inFigure 2 The first cut corner 130 can be a triangle as shown in FIG. 1B, or a rectangle as shown in FIG. 1C, or a square, a pentagon, or other polygon. The second cut corner of the negative tab 200 can also be an arc or any of the polygons. When the first cut corner 130 and the second cut corner are rectangles, a structure as shown in FIG. 1D is formed. Figure 2 Figure 4 In addition, the first cut corner 130 shown in FIG. 1A can be formed by rounding the corner of the positive tab 100, and the rounding R1 is 0.5 mm to 4 mm. Similarly, the second cut corner can also be formed by rounding the corner of the negative tab 200, and the rounding R2 is 0.5 mm to 4 mm.

[0055] In addition, the first cut corner 130 shown in FIG. 1A can be formed by rounding the corner of the positive tab 100, and the rounding R1 is 0.5 mm to 4 mm. Similarly, the second cut corner can also be formed by rounding the corner of the negative tab 200, and the rounding R2 is 0.5 mm to 4 mm. Figure 2 The battery cell 10 has opposite first and second ends 12 and 13 along its thickness direction. It should be noted that during the battery assembly process, the battery cell 10 often needs to be placed in the accommodating cavity 21 formed after the aluminum plastic film 20 is punched. The first end 12 of the battery cell 10 is placed at the bottom of the accommodating cavity 21 for abutting against the bottom wall of the accommodating cavity 21. Correspondingly, the second end 13 of the battery cell 10 is located at the top of the accommodating cavity 21. The accommodating cavity 21 formed after the punching often has a trapezoidal shape. Specifically, the accommodating cavity 21 includes four side walls and a bottom wall. Adjacent side walls are connected by a circular arc. As shown in FIG. 1E, the distance between the opposite side walls gradually increases along the direction perpendicular to and away from the bottom wall.

[0056] Figure 9 That is, for the same corner position of the battery cell 10, the distance between the corner position and the cavity wall of the accommodating cavity 21 is smaller at the bottom, and the risk of the tab being squeezed and scratched is greater. The distance between the corner position and the cavity wall of the accommodating cavity 21 is larger at the top, and the risk of the tab being squeezed and scratched is smaller.

[0057] Therefore, the present application performs different degrees of cutting on the height position of the tab when cutting the corner. Specifically, along the direction from the first end 12 to the second end 13, the area of the adjacent first cut corner 130 gradually decreases, and the area of the adjacent second cut corner gradually decreases. The first cut corner 130 and the second cut corner correspondingly communicate to form a cut structure 11 at the corner position of the battery cell 10. That is, the cut structure 11 has a large bottom and a small top, so that the bottom of the battery cell 10 can maintain a certain distance from the cavity wall of the accommodating cavity 21, and the cut area of the top is smaller, which is beneficial to reduce the influence of the cut corner on the energy density of the battery.

[0058] It can be understood that for the laminated battery cell 10, the shapes of the cut corners on the tabs can not be completely the same. For example, in the embodiment shown in FIG. 1F, it should be noted that Figure 3 Figure 3 FIG. 1G is a schematic view of the battery cell 10 observed in the direction from the first end 12 to the second end 13. In the embodiment shown in FIG. 1G,​​​Figure 3 In the embodiment, the shapes of the cutout corners in the cutout structure 11 are not all the same, and the cutout corner closest to the first end 12 is a concave cutout corner, and along the direction away from the first end 12, the cutout corner area gradually decreases, and the shape of the cutout corner gradually changes to a convex cutout corner.

[0059] It should be noted that for the stack cell 10 of the first aspect embodiment, the corner position cutout can be performed by a die-cutting process or the like when manufacturing the pole piece, and then the pole pieces after the cutout of the corners are stacked to form the cell 10 (as shown in Figure 3 Alternatively, the corners of each edge position can also be uniformly cut after the stack cell 10 is stacked (not shown in the figure).

[0060] Based on the above, the cell 10 of the present application forms a cutout structure 11 at the corner position, thereby avoiding the circular arc transition section of the aluminum plastic film 20, increasing the distance between the cell 10 and the aluminum plastic film 20 at the corner position, avoiding the problem of pole piece scratching and deformation, and at the same time, the distance between the cell 10 and the aluminum plastic film 20 at the side position is small, which is beneficial to improve the energy density of the cell 10. Moreover, for the structure that the top of the accommodating cavity 21 is wide and the bottom is narrow, the cutout structure 11 is designed accordingly, and along the direction away from the bottom of the accommodating cavity 21, the size of the cutout structure 11 gradually decreases, thereby further reducing the influence of the cutout corner on the energy density of the cell 10.

[0061] In some embodiments, as shown in Figure 5 and Figure 6 along the direction from the first end 12 to the second end 13, the size of the positive pole piece 100 gradually increases, and the size of the negative pole piece 200 also gradually increases. Based on the foregoing, since the distance between the opposite side walls of the accommodating cavity 21 gradually increases along the direction away from the bottom wall, the entire accommodating cavity 21 is arranged in a trapezoidal shape, and thus the distance between the bottom edge of the cell 10 and the cavity wall of the accommodating cavity 21 is small, and the distance between the top edge and the cavity wall of the accommodating cavity 21 is large, which is prone to cause the phenomenon of space waste. Therefore, the cell 10 of the present application is arranged in a trapezoidal shape that is adapted to the accommodating cavity 21. The size of the pole piece close to the bottom end of the accommodating cavity 21 is small, and the size of the pole piece away from the bottom end of the accommodating cavity 21 is large.

[0062] Specifically, in some embodiments, the cutout corner area of the two adjacent negative pole pieces 200 increases by 3% to 30% along the direction from the second end 13 to the first end 12, that is, in any two adjacent negative pole pieces 200, the negative pole piece 200 close to the first end 12 is defined as the first negative pole piece, and the negative pole piece 200 close to the second end 13 is defined as the second negative pole piece, and the cutout corner area of the first negative pole piece is 1.03 to 1.3 times the cutout corner area of the second negative pole piece.

[0063] Similarly, the cut corner area of the two adjacent positive electrode sheets 100 increases by 3% to 30% from the second end 13 to the first end 12, that is, in any two adjacent positive electrode sheets 100, the positive electrode sheet 100 close to the first end 12 is defined as the first positive electrode sheet, and the positive electrode sheet 100 close to the second end 13 is defined as the second positive electrode sheet. The cut corner area of the first positive electrode sheet is 1.03 to 1.3 times that of the second positive electrode sheet.

[0064] In more detail, two of the side walls of the accommodation cavity 21 are arranged opposite in the width direction, and the other two side walls are arranged opposite in the length direction. In the direction away from the bottom wall, the distance between the two side walls arranged opposite in the width direction gradually increases, and the distance between the two side walls arranged opposite in the length direction also gradually increases. Thus, with reference to Figure 5 and Figure 6 As shown, in the direction from the first end 12 to the second end 13, the width and length of the upper layer of positive electrode sheets 100 are wider and longer than those of the lower layer of positive electrode sheets 100. The width and length of the upper layer of negative electrode sheets 200 are wider and longer than those of the lower layer of negative electrode sheets 200. For some embodiments, if the distance between the two side walls arranged opposite in the width direction gradually increases and the distance between the two side walls arranged opposite in the length direction is constant in the accommodation cavity 21 formed on the aluminum plastic film 20, the width of the upper layer of electrode sheets is wider than that of the lower layer of electrode sheets, and the length is unchanged. If the distance between the two side walls arranged opposite in the length direction gradually increases and the distance between the two side walls arranged opposite in the width direction is constant in the accommodation cavity 21 formed on the aluminum plastic film 20, the length of the upper layer of electrode sheets is longer than that of the lower layer of electrode sheets, and the width is unchanged.

[0065] Further, the positive electrode sheet 100 includes a positive electrode current collector 110 and a positive electrode active layer 120, and the negative electrode sheet 200 includes a negative electrode current collector 210 and a negative electrode active layer 220. It can be understood that the positive electrode active layer 120 and the negative electrode active layer 220 are arranged adjacent to each other and separated by a separator. During electrochemical reaction, lithium ions on the positive electrode active layer 120 are embedded into the negative electrode active layer 220 through the separator. In this application, in the adjacent positive electrode active layer 120 and negative electrode active layer 220, the projection area of the positive electrode active layer 120 is required to fall within the projection area of the negative electrode active layer 220 in the projection from the first end 12 to the second end 13, that is, the width and length dimensions of the positive electrode active layer 120 are not greater than the dimensions of the negative electrode active layer 220, so as to avoid the phenomenon of lithium precipitation caused by the amount of lithium ions released by the positive electrode active layer 120 being greater than the number of lithium-embedding sites of the negative electrode active layer 220.

[0066] Further, the positive electrode sheet 100 includes a positive electrode double-sided sheet and a positive electrode single-sided sheet. The positive electrode double-sided sheet is a positive electrode sheet 100 in which the positive electrode current collector 110 has two surfaces coated with the positive electrode active layer 120 in the thickness direction of the positive electrode current collector 110. The positive electrode single-sided sheet is a positive electrode sheet coated with the positive electrode active layer 120 on one side. For example,Figure 5 and Figure 6 In the illustrated embodiment, the outermost side of the battery cell 10 is a single-sided positive electrode sheet. Similarly, the negative electrode sheet 200 includes a double-sided negative electrode sheet, wherein the double-sided sheet is a negative electrode sheet 200 in which the two surfaces of the negative electrode current collector 210 along its thickness direction are respectively coated with a negative electrode active layer 220. Figure 5 In the embodiment shown, the negative electrode active layer 220 on both surfaces of the negative electrode double-sided sheet has the same size, so that the same parameters can be ensured when coating the negative electrode active layer 220, and the chemical properties on both sides are the same, so there is no need to consider the front and back sides when stacking.

[0067] In other embodiments, such as Figure 6 As shown, the negative electrode active layers 220 on the two surfaces of the negative electrode double-sided sheet have different sizes; the size of the negative electrode active layer 220 near the first end 12 is smaller than the size of the negative electrode active layer 220 near the second end 13. Figure 6 Taking the example shown, the first end 12 is the right side and the second end 13 is the left side. The size of the negative active layer 220 on the left side of the negative electrode 200 needs to be larger than the size of the positive active layer 120 on the right side of the positive electrode 100 on the left side. The size of the negative active layer 220 on the right side of the negative electrode 200 needs to be larger than the size of the positive active layer 120 on the left side of the positive electrode 100 on the right side. Since the size of the positive electrode 100 on the left side is larger than the size of the positive electrode 100 on the right side, if the sizes of the negative active layers 220 on the left and right sides of the negative electrode 200 are set to be the same, the size of the negative active layer 220 on the right side will be much larger than the size of the positive active layer 120 on the left side of the positive electrode 100 on the right side, thus wasting the negative active material. Therefore, the sizes of the negative active layers 220 on the left and right sides of the negative electrode 200 can be set to be different so that the size of the negative active layer 220 near the first end 12 is smaller than the size of the negative active layer 220 near the second end 13.

[0068] Correspondingly, the size difference between the negative electrode active layer 220 and the positive electrode active layer 120 can be reduced by adjusting the size of the positive electrode active layer 120 on both sides of the positive electrode sheet 100. Under the premise that the negative electrode active layer 220 covers the positive electrode active layer 120, the active material will not be wasted due to excessive size difference, thereby further improving the energy density of the battery.

[0069] The second aspect of this application also proposes another type of battery cell 10, such as... Figure 7As shown, the battery cell 10 is a winding battery cell 10, which includes a diaphragm, a positive electrode sheet 100 and a negative electrode sheet 200. Different from the stacking battery cell 10, the positive electrode sheet 100 and the negative electrode sheet 200 in the winding battery cell 10 are both in the structure of an entire strip. The positive electrode sheet 100, the diaphragm and the negative electrode sheet 200 are wound to form the winding battery cell 10. Adjacent positive electrode sheets 100 and negative electrode sheets 200 are separated by the diaphragm.

[0070] It can be understood that, as Figure 8 shown, the positive electrode sheet 100 is provided with a plurality of first cut corners 130 on both side edges in the width direction thereof, and the first cut corners 130 are arranged at intervals along the length direction of the positive electrode sheet 100. The negative electrode sheet 200 is provided with a plurality of second cut corners (not shown in the figure) on both side edges thereof, and the second cut corners are arranged along the length direction of the negative electrode sheet 200. It can be understood that the intervals of the first cut corners 130 and the second cut corners are not the same, and need to be set according to the positions after winding. After the positive electrode sheet 100 and the negative electrode sheet 200 are attached, the first cut corners 130 and the second cut corners at the corresponding positions thereof are communicated, and then the positive electrode sheet 100 and the negative electrode sheet 200 are wound to form a structure of layers from inside to outside. The first cut corners 130 and the second cut corners of adjacent layers are correspondingly communicated to form a cut structure 11 at the corner position of the battery cell 10. It should be noted that, Figure 7 shown is a schematic view of the battery cell 10 formed after the positive electrode sheet with square cut corners is wound, rather than Figure 8 shown is a schematic view of the battery cell 10 formed after the positive electrode sheet is wound. Figure 7 and Figure 8 there is no corresponding relationship between them.

[0071] It should be noted that, similar to the first aspect of the present application, the cut structure 11 on the battery cell 10 also presents a structure that the size near the first end 12 is larger and the size near the second end 13 is smaller. Specifically, in the direction from the first end 12 to the second end 13, the area of the first cut corner 130 of the adjacent layer gradually decreases, and the area of the second cut corner of the adjacent layer gradually decreases.

[0072] It can be understood that, in order to meet the requirement that the negative active layer 220 covers the positive active layer 120, the width of the negative active layer 220 on the positive electrode sheet 100 is greater than the width of the positive active layer 120, so as to reduce the risk of lithium precipitation.

[0073] In the second aspect of this application, the first chamfer 130 and the second chamfer are formed on the edge of the electrode sheet through processes such as die-cutting and laser cutting. The first chamfer 130 can be any of an arc or a polygon, and a polygon includes triangles, squares, rectangles, etc. The second chamfer can also be any of an arc or a polygon. It is understood that the various first chamfers 130 can be the same or not completely the same. The first chamfers 130 that are connected to each other should be the same, and the shapes of the first chamfers 130 and the second chamfer that are connected to each other should be the same.

[0074] It should be noted that, whether it is the stacked battery cell in the first aspect embodiment or the wound battery cell in the second aspect embodiment, the area of ​​the cut-out structure 11 at the first end 12 is 1.8 to 2 times the area of ​​the second end 13. The number of layers in the stacked battery cell of this application is preferably 7 to 30 layers, and the number of layers in the wound battery cell is also preferably 7 to 30 layers. It should be noted that the number of layers increases by two for each turn of the wound battery cell.

[0075] A third aspect of this application provides a battery, such as Figure 9 As shown, the battery includes an aluminum-plastic film 20 and a battery cell 10 mentioned in any of the above embodiments. The battery cell 10 can be a stacked battery cell 10 or a wound battery cell 10. The aluminum-plastic film 20 defines a receiving cavity 21, and the first end 12 of the battery cell 10 is placed at the bottom of the receiving cavity 21. If the receiving cavity 21 is deep, the battery cell 10 is completely located in the receiving cavity 21, and the second end 13 of the battery cell 10 is located at the top of the receiving cavity 21. If the receiving cavity 21 is shallow, the top of the battery cell 10 is exposed outside the receiving cavity 21, and it needs to be covered by the other half of the aluminum-plastic film 20 to obtain a closed cavity.

[0076] Understandably, based on the foregoing, the accommodating cavity 21 is formed by stamping. The accommodating cavity 21 includes four side walls and a bottom wall. Due to the limitations of the process and equipment, the adjacent side walls are rounded, and the distance between the opposite side walls gradually increases in the direction away from the bottom wall.

[0077] Therefore, at the first end 12 of the cell 10, the distance from the edge of the cut-out structure 11 to the sidewall of the accommodating cavity 21 is defined as 1.8 mm to 2.8 mm, and at the second end 13 of the cell 10, the distance from the edge of the cut-out structure 11 to the sidewall of the accommodating cavity 21 is defined as 3.5 mm to 4.5 mm. It is understandable that if the distance is too small, the cell 10 will expand due to heat during charging and discharging, causing it to scratch the aluminum-plastic film 20. If the distance is too large, it will affect the energy density within the battery, resulting in wasted space within the battery.

[0078] Based on the above, the battery of the application can avoid the decrease of the yield rate caused by the collision or scratching of the pole piece during the assembly process, and can avoid the piercing of the aluminum plastic film 20 caused by the heat expansion of the battery cell 10 during use, so that the battery has good safety performance. And the energy density of the battery is high.

[0079] The fourth aspect embodiment of the application further provides a power consuming device, which comprises the battery mentioned in the above embodiments. The power consuming device can be a mobile phone, a computer, or other 3C digital products, or a robot vacuum cleaner, a projector, or other household appliances, or a new energy vehicle, or other transportation tools. It can be understood that the power consuming device comprises the battery in any of the above embodiments, thereby having the technical effects brought by the battery in the above embodiments, which will not be repeated here.

[0080] The embodiments of the application are described in detail above in combination with the drawings, but the application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the purpose of the application. In addition, the embodiments of the application and the features in the embodiments can be combined with each other without conflict.

Claims

1. An electric cell, characterized by, The electric core comprises a separator, a plurality of positive electrode sheets and a plurality of negative electrode sheets, the plurality of positive electrode sheets and the plurality of negative electrode sheets are alternately and laminated to form a laminated core, and adjacent positive electrode sheets and negative electrode sheets are separated by the separator; Wherein, the edge corner position of each positive electrode sheet is provided with a first cut corner, the edge corner position of the negative electrode sheet is provided with a second cut corner, the electric core has opposite first and second ends along its thickness direction, and the area of the adjacent first cut corner gradually decreases along the direction from the first end to the second end, the area of the adjacent second cut corner gradually decreases, and the first cut corner and the second cut corner correspondingly communicate to form a cut structure at the edge corner position of the electric core.

2. The electric cell of claim 1, wherein, Along the direction from the first end to the second end, the size of the positive electrode sheet gradually increases, and the size of the negative electrode sheet gradually increases.

3. The electric cell of claim 2, wherein, The positive electrode sheet comprises a positive electrode current collector and a positive electrode active layer, the negative electrode sheet comprises a negative electrode current collector and a negative electrode active layer, and in adjacent positive electrode active layers and negative electrode active layers, the projection area of the positive electrode active layer falls within the projection area of the negative electrode active layer along the projection from the first end to the second end.

4. The electric cell of claim 3, wherein, The negative electrode sheet comprises a negative electrode double-sided sheet, in which the negative electrode current collector is coated with the negative electrode active layer on both surfaces along its thickness direction, and the sizes of the negative electrode active layers on the two surfaces are the same or different; And / or, the positive electrode sheet comprises a positive electrode double-sided sheet, in which the positive electrode current collector is coated with the positive electrode active layer on both surfaces along its thickness direction, and the sizes of the positive electrode active layers on the two surfaces are the same or different.

5. The electric cell of claim 1, wherein, The edge corner position of the positive electrode sheet forms the first cut corner through chamfering, the first cut corner R1 is 0.5mm to 4mm, and / or the edge corner position of the negative electrode sheet forms the second cut corner through chamfering, the second cut corner R2 is 0.5mm to 4mm.

6. The electric cell of claim 1, wherein, In any two adjacent negative electrode sheets, the negative electrode sheet close to the first end is set as a first negative electrode sheet, and the negative electrode sheet close to the second end is set as a second negative electrode sheet, the cut corner area of the first negative electrode sheet is 1.03 to 1.3 times that of the second negative electrode sheet; And / or, in any two adjacent positive electrode sheets, the positive electrode sheet close to the first end is set as a first positive electrode sheet, and the positive electrode sheet close to the second end is set as a second positive electrode sheet, the cut corner area of the first positive electrode sheet is 1.03 to 1.3 times that of the second positive electrode sheet.

7. An electric cell, characterized by The electric core comprises a separator, a positive electrode sheet and a negative electrode sheet, the positive electrode sheet, the separator and the negative electrode sheet are wound to form a wound core, and adjacent positive electrode sheets and negative electrode sheets are separated by the separator; The two side edges of the positive electrode sheet are respectively provided with a plurality of first cut corners arranged along the length direction thereof at intervals, the two side edges of the negative electrode sheet are respectively provided with a plurality of second cut corners arranged along the length direction thereof at intervals, the first cut corners and the second cut corners are correspondingly arranged, the battery cell has opposite first and second ends along the thickness direction thereof, the area of the first cut corner of the adjacent coil layer gradually decreases along the direction from the first end to the second end, the area of the second cut corner of the adjacent coil layer gradually decreases, and each of the first cut corner and the second cut corner is correspondingly connected to form a cut structure at the corner position of the battery cell.

8. The electric cell of claim 7, wherein, The positive electrode sheet comprises a positive electrode current collector and a positive electrode active layer, and the negative electrode sheet comprises a negative electrode current collector and a negative electrode active layer, and the width of the negative electrode active layer is greater than the width of the positive electrode active layer.

9. The cell of claim 1 or 7, wherein, The first cut corner is in any one of an arc shape and a polygonal shape, and / or the second cut corner is in any one of an arc shape and a polygonal shape, and the first cut corner and the second cut corner connected to each other have the same shape.

10. The cell of claim 1 or 7, wherein, The area of the cut structure at the first end is 1.8 to 2 times the area of the cut structure at the second end.

11. A battery characterized by It comprises: An aluminum plastic film, which defines a containing cavity; The battery cell according to any one of claims 1 to 10, wherein the first end of the battery cell is placed at the bottom of the containing cavity.

12. The battery of claim 11, wherein, At the first end of the battery cell, the distance from the edge of the cut structure of the battery cell to the side wall of the containing cavity is 1.8 to 2.8 mm. And / or, at the second end of the battery cell, the distance from the edge of the cut structure of the battery cell to the side wall of the containing cavity is 3.5 to 4.5 mm.

13. The battery of claim 11, wherein, The containing cavity comprises four side walls and a bottom wall, adjacent side walls are circularly arc transitioned, and the distance between the opposite side walls gradually increases in the direction away from the bottom wall.

14. An electrical device, characterized by It comprises the battery according to any one of claims 11 to 13.

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