Electrode sheet, wound battery cell, and battery

Abstract

To provide an electrode sheet capable of suppressing the generation of wrinkles on a collector in a roll press step.SOLUTION: The present invention relates to an electrode sheet, a winding type battery cell, and a battery. The electrode sheet comprises: a collector; and a first active material layer 11 that is applied on a front surface of the collector. In the first active material layer, a first concave groove containing a first side wall B1, a second side wall B2, and a third side wall B3 is provided. The first concave groove is surrounded by the first, second, and third side walls. A vertical distance from the first side wall to the second side wall is a width of the first concave groove. A shape of an orthogonal projection to a front surface of the collector of the third side wall is a border line L1 of the third side wall, a length of the border line is larger than the width of the first concave groove. By increasing the length of the border line than the width of the first concave groove, an area of the collector in the first concave groove becomes larger, a pressure against the collector of the active layer in a unit area becomes smaller, an extension ratio of the collector becomes smaller, and winkles generated on the collector are reduced.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] (Cross - reference to related applications) This disclosure is based on and claims priority to Chinese Patent Application No. 202020761606 filed on May 9, 2020, and all of its contents are incorporated herein by reference. .8, and all of its contents are incorporated herein by reference. This disclosure relates to the field of batteries, and particularly to electrode sheets, wound battery cells, and batteries.

[0002]

Background Art

Background Art

[0003] The electrode sheet of a battery includes a current collector and an active material coated on the surface of the current collector. The current collector is usually aluminum foil or copper foil. In the current manufacturing process of the electrode sheet of a battery, in order to obtain an electrode sheet that meets the design parameters, the electrode sheet must be roll - pressed. However, in the process of performing the roll - pressing step, it is necessary to compress the active material, and at the same time, the active material presses the foil, and finally a certain tension is generated in the foil. Since no tension is generated at the position where the active material layer is not coated, there is a difference in tension between the position with the active material and the position without the active material. Externally, small wrinkles are generated at the edge of the foil, and in more serious cases, wrinkles are generated. When wrinkles are generated in the concave grooves of the electrode sheet, it affects the welding strength of the tab, causes welding defects, increases the resistance of the battery, speeds up the heat generation during the charge and discharge process of the battery, and speeds up the attenuation of the cycle life. At the connection part between the concave groove and the active material, the active material is more likely to fall off, resulting in a serious quality problem that the foil is exposed in the electrode sheet.

Summary of the Invention

[0004]

Summary of the Invention

[0004] The present disclosure provides an electrode sheet, a wound battery cell, and a battery, and solves problems such as exposure of foil pieces of the electrode sheet of the battery due to wrinkles generated in the current collector during the roll pressing process of the electrode sheet, short cycle life of the cell, and fast heat generation of the battery.

[0005] To achieve the object of the present disclosure, the present disclosure provides the following technical solutions.

[0006] In a first aspect, the electrode sheet according to the present disclosure includes a current collector and a first active material layer coated on the surface of the current collector, and a first concave groove including a first side wall, a second side wall, and a third side wall is provided in the first active material layer. The first side wall and the second side wall are installed opposite to each other and are parallel to each other. The third side wall is connected to the first side wall and the second side wall, and the first concave groove is surrounded by the first side wall, the second side wall, and the third side wall. The vertical distance from the first side wall to the second side wall is the width of the first concave groove. The shape of the orthographic projection of the third side wall on the surface of the current collector is the contour line of the third side wall, and the length of the contour line is greater than the width of the first concave groove.

[0007] The contour line is a curve or a straight line.

[0008] The contour line is a curve including only an arc line or a combination of a straight line and an arc line.

[0009] The contour line is an arc line, and the radius of the arc line is half of the width of the first concave groove, and in this case, the degree of wrinkles generated in the current collector is the lowest.

[0010] The First active material layer ​​​It includes opposite first and second sides, and the first concave groove extends from the first side towards the second side. When the contour line is a curve, the contour line is recessed in the direction of the second side.

[0011] The electrode sheet further includes a second active material layer disposed on the surface of the current collector facing away from the first active material layer. The second active material layer has a second concave groove identical to the first concave groove. installed.

[0012] The second concave groove and the first concave groove are either directly opposite or arranged alternately.

[0013] The second concave groove extends from the second side towards the first side.

[0014] In a second aspect, the wound battery cell according to the present disclosure includes a separator and an electrode sheet according to any one of the various embodiments of the first aspect, and the separator is installed between two said electrode sheets. In a second aspect, the wound battery cell according to the present disclosure includes a separator and an electrode sheet according to any one of the various embodiments of the first aspect, and the separator is installed between two said electrode sheets. installed.

[0015] In a third aspect, the battery according to the present disclosure includes the wound battery cell according to the second aspect.

[0016] By making the length of the contour line of the third side wall greater than the width of the first concave groove, the perimeter of the first concave groove becomes longer, the area of the current collector in the first concave groove becomes larger, and in the case of roll pressing, the force-receiving area of the current collector in the first concave groove becomes larger, the pressure exerted on the current collector of the active material layer per unit area becomes smaller, the elongation rate of the current collector becomes smaller, thereby reducing the phenomenon of wrinkles occurring in the current collector. By making the length of the contour line of the third side wall greater than the width of the first concave groove, the perimeter of the first concave groove becomes longer, the area of the current collector in the first concave groove becomes larger, and in the case of roll pressing, the force-receiving area of the current collector in the first concave groove becomes larger, the pressure exerted on the current collector of the active material layer per unit area becomes smaller, the elongation rate of the current collector becomes smaller, thereby reducing the phenomenon of wrinkles occurring in the current collector. By making the length of the contour line of the third side wall greater than the width of the first concave groove, the perimeter of the first concave groove becomes longer, the area of the current collector in the first concave groove becomes larger, and in the case of roll pressing, the force-receiving area of the current collector in the first concave groove becomes larger, the pressure exerted on the current collector of the active material layer per unit area becomes smaller, the elongation rate of the current collector becomes smaller, thereby reducing the phenomenon of wrinkles occurring in the current collector. By making the length of the contour line of the third side wall greater than the width of the first concave groove, the perimeter of the first concave groove becomes longer, the area of the current collector in the first concave groove becomes larger, and in the case of roll pressing, the force-receiving area of the current collector in the first concave groove becomes larger, the pressure exerted on the current collector of the active material layer per unit area becomes smaller, the elongation rate of the current collector becomes smaller, thereby reducing the phenomenon of wrinkles occurring in the current collector. and reducing the phenomenon of wrinkles occurring in the current collector.

Brief Description of the Drawings

[0017] To more clearly illustrate the technical solutions in the embodiments of the present disclosure or in the prior art, The following briefly introduces the drawings necessary for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those skilled in the art, without any creative labor required, other drawings can be obtained based on these drawings.

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Embodiments for Carrying Out the Invention

[0018] The following clearly and completely describes the technical solution means in the embodiments of the present disclosure with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, not all of them. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present disclosure.

[0019] ​As shown in FIGS. 1 and 10, an embodiment of the present disclosure provides a battery 100 including a battery case K, a wound battery cell J disposed in the battery case K, and a battery upper cover G. The wound battery cell J is provided by an embodiment of the present disclosure, and its specific structure will be described later. The battery case K may be a cylinder with an open upper end. The bottom of the inner wall of the cylinder is electrically connected to the negative electrode current collector plate of the wound battery cell J. In the middle of the outer bottom of the battery case K, a boss T1 for connecting the negative electrode of the battery to an external device is installed. The battery upper cover G is a disk-shaped cover that mates with the battery case K. A flat surface protruding downward is installed at its lower part, which is electrically connected to the positive electrode current collector plate. An insulating seal ring is attached between the positive electrode current collector plate and the battery case K. In the middle of the upper part of the battery upper cover G, a cylindrical boss T2 protruding upward for connecting the positive electrode of the battery to an external device is installed. An electrolyte injection port D is installed on the battery upper cover G. By injecting the electrolyte, electron conduction between the positive and negative electrodes is realized, and after the electrolyte is injected, it is sealed with a sealing pin. The battery 100 with such a structure generates less heat during the charge and discharge process and has a slow decay rate during recycling, so the service life of the battery 100 can be extended. By using the wound battery cell J according to the present disclosure, the phenomenon of wrinkles occurring on the electrode sheet is reduced, and further wrinkles do not occur, the resistance of the battery 100 can be reduced, the heat generation of the battery 100 can be slowed down, and at the same time, the occurrence of the phenomenon of the exposure of the current collector due to the peeling of the active material layer of the electrode sheet can be reduced, and the service life of the battery 100 can be extended. As shown in FIG. 2, an embodiment of the present disclosure provides a wound battery cell J. The wound battery cell J is provided by an embodiment of the present disclosure, and its specific structure will be described later. The battery case K may be a cylinder with an open upper end. The bottom of the inner wall of the cylinder is electrically connected to the negative electrode current collector plate of the wound battery cell J. In the middle of the outer bottom of the battery case K, a boss T1 for connecting the negative electrode of the battery to an external device is installed. The battery upper cover G is a disk-shaped cover that mates with the battery case K. A flat surface protruding downward is installed at its lower part, which is electrically connected to the positive electrode current collector plate. An insulating seal ring is attached between the positive electrode current collector plate and the battery case K. In the middle of the upper part of the battery upper cover G, a cylindrical boss T2 protruding upward for connecting the positive electrode of the battery to an external device is installed. An electrolyte injection port D is installed on the battery upper cover G. By injecting the electrolyte, electron conduction between the positive and negative electrodes is realized, and after the electrolyte is injected, it is sealed with a sealing pin. The battery 100 with such a structure generates less heat during the charge and discharge process and has a slow decay rate during recycling, so the service life of the battery 100 can be extended. By using the wound battery cell J according to the present disclosure, the phenomenon of wrinkles occurring on the electrode sheet is reduced, and further wrinkles do not occur. The resistance of the battery 100 can be reduced, the heat generation of the battery 100 can be slowed down. At the same time, the occurrence of the phenomenon of the exposure of the current collector due to the peeling of the active material layer of the electrode sheet can be reduced, and the service life of the battery 100 can be extended. As shown in FIG. 2, an embodiment of the present disclosure provides a wound battery cell J. The wound battery cell J is provided by an embodiment of the present disclosure, and its specific structure will be described later.

[0020] As shown in FIG. 2, an embodiment of the present disclosure provides a wound battery cell J, and the wound battery cell J includes a separator 3, an electrode sheet 1 and an electrode sheet 2 according to an embodiment of the present disclosure, and the electrodes sheet 1 and electrode sheet 2 may be a positive electrode sheet and a negative electrode sheet, and the separator 3 is usually a polymer material having nanoscale pores, and is installed between the electrode sheet 1 and the electrode sheet 2 to isolate the two electrode sheets, thereby avoiding problems such as short circuit due to contact between the positive and negative electrodes and allowing electrolyte ions to pass through. The electrode sheet 1, the separator 3 and the electrode sheet 2 are stacked and installed, and wound by a dedicated winding machine to manufacture a wound battery cell J. By using the electrode sheet according to the present disclosure, the phenomenon of wrinkles occurring on the electrode sheet is reduced, and further wrinkles do not occur, reducing the peeling of the active material layer of the electrode sheet and extending the service life of the cell.

[0021] As shown in FIGS. 3 and 4, the present disclosure provides an electrode sheet including a current collector 10 and a first active material layer 11 coated on the surface of the current collector 10. In the first active material layer 11, a first concave groove C1 including a first side wall B1, a second side wall B2, and a third side wall B3 is provided. The first side wall B1 and the second side wall B2 are installed opposite to each other and parallel to each other, and the third side wall B3 is connected to the first side wall B1 and the second side wall B2, and the first concave groove C1 is surrounded by the first side wall B1, the second side wall B2, and the third side wall B3. The vertical distance from the first side wall B1 to the second side wall B2 is the width 4 of the first concave groove C1, and the shape of the orthographic projection of the third side wall B3 on the surface of the current collector 10 is the contour line L1 of the third side wall B3, and the length of the contour line L1 is larger than the width 4 of the first concave groove C1. C1.

[0022] By making the length of the contour line L1 of the third side wall B3 greater than the width of the first concave groove C1, the perimeter of the first concave groove C1 becomes longer, and the area of the current collector 10 in the first concave groove C1 becomes larger In the case of roll pressing, the force-receiving area of the current collector 10 in the first concave groove C1 becomes larger, the pressure of the first active material layer 11 on the current collector 10 per unit area becomes smaller, and the elongation rate of the current collector 10 becomes smaller, thereby reducing the phenomenon of wrinkles occurring in the current collector 10.

[0023] In one embodiment, as shown in FIGS. 3, 5 to 8, the contour line L1 of the third side wall B3 is a curve or a straight line. By setting the linear shape of the contour line L1 to a curve or a straight line, the force-receiving area of the current collector 1 0 can be increased, the magnitude of the pressure received by the current collector 10 per unit area can be reduced, and the elongation rate of the current collector 10 can be further reduced.

[0024] In one embodiment, as shown in FIG. 5, the contour line L1 of the third side wall B3 is a straight line, and the straight line is not perpendicular to the first side wall B1 and the second side wall B2, but is inclined with an included angle facing each other obliquely.

[0025] In one embodiment, as shown in FIG. 3, the contour line L1 of the third side wall B3 is a curve including only an arc line According to some embodiments of the present disclosure, the contour line L1 is an arc line, and the radius of the arc line is half of the width 4 of the first concave groove C1. In this case, the perimeter of the first concave groove C1 is the longest, the force-receiving area of the current collector 10 in the first concave groove C1 is the largest, and the degree of wrinkles generated in the current collector 1 0 is the lowest. In other embodiments, the radius of the arc line may be greater than or less than the width 4 of the first concave groove C1.

[0026] In another embodiment, as shown in FIG. 6, the contour line L1 of the third side wall B3 is a curve including an S-shaped curve composed of two semi-circular arcs with equal diameters, and the diameter of the semi-circular arc is half of the width of the first concave groove C1.

[0027] In another embodiment, as shown in FIG. 7, the contour line L1 of the third side wall B3 is a curve including a combination of an arc line and a straight line. The arc line may be any arc line such as a quarter circle arc or a half circle arc, and the straight line may be a straight line perpendicular or inclined to the first side wall B1. In another embodiment, the contour line L1 of the third side wall B3 may be a curve including a free curve of any shape.

[0028] In one embodiment, as shown in FIGS. 3 and 4, First active material layer 11 includes the first side 5 and the second side 6 located on the opposite sides. The first concave groove C1 and the second concave groove C2 extend from the first side 5 to the second side 6. The contour line L1 of the first concave groove C1 is a curve that depresses from the first side 5 to the second side 6, and the second concave groove C2 has the same structure as the first concave groove C1.

[0029] In one embodiment, as shown in FIGS. 8 and 9, First active material layer 11 includes the first side 5 and the second side 6 located on the opposite sides. The electrode sheet further includes a second active material layer 12 disposed on the surface of the current collector 10 facing away from the first active material layer 11, and a second concave groove C2 identical to the first concave groove C1 is disposed in the second active material layer 12.

[0030] In one embodiment, as shown in FIG. 8, the contour line L1 of the first concave groove C1 extends from the first side 5 to the second side 6, and the contour line L1 of the third side wall B3 of the first concave groove C1 depresses from the first side 5 to the second side 6. The second concave groove C2 extends from the second side 6 to the first side 5, ​​​The contour line L2 of the third side wall of the second concave groove C2 is recessed from the second side 6 to the first side 5.

[0031] In one embodiment, as shown in FIGS. 3 and 4, the first concave groove C1 and the second concave groove C2 face each other.

[0032] In one embodiment, as shown in FIGS. 8 and 9, the first concave groove C1 and the second concave groove C2 are alternately arranged.

[0033] The content disclosed above is only a preferred embodiment of the present disclosure and does not limit the scope of the claims of the present disclosure. As can be understood by those skilled in the art, all or part of the flow for realizing the above embodiment and equivalent changes made based on the claims of the present disclosure still fall within the scope of the present disclosure.

Explanation of Reference Numerals

[0034] 100 Battery K Battery Case J Wound Battery Cell G Battery Upper Cover D Electrolyte Inlet T1 Boss T2 Cylindrical Boss 1 / 2 Electrode Sheet 3 Separator 10 Current Collector 11 First Active Material Layer 12 Second Active Material Layer C1 First Concave Groove C2 Second Concave Groove B1 First Side Wall B2 Second Side Wall B3 Third Side Wall L1 Contour Line of the Third Side Wall of the First Concave Groove L2 Contour Line of the Third Side Wall of the Second Concave Groove 4 Width of the First Concave Groove C1 5 First Side 6 Second Side

Claims

1. An electrode sheet comprising a current collector and a first active material layer applied to a first surface of the current collector, a first groove including a first side wall, a second side wall and a third side wall is provided in the first active material layer, the first side wall and the second side wall are parallel to each other, the third side wall is connected to the first side wall and the second side wall, and a width of the first groove is a distance from the first side wall to the second side wall; a shape of the third side wall when orthogonally projected onto the first surface of the current collector is a contour line of the third side wall, and a length of the contour line is greater than a width of the first groove; An electrode sheet, wherein the contour line is a curved line.

2. The electrode sheet according to claim 1 , wherein the contour line is a curve including a combination of a straight line and an arc line.

3. An electrode sheet as described in claim 2, wherein the arc line is a quarter arc line.

4. 3. The electrode sheet according to claim 2, wherein the first active material layer includes a first side edge and a second side edge located on opposite sides, and the first groove extends in a direction from the first side edge to the second side edge.

5. 5. The electrode sheet according to claim 4, further comprising a second active material layer disposed on a second surface of the current collector opposite to the first surface on the first active material layer side, the second active material layer including a second groove.

6. The electrode sheet according to claim 5 , wherein the second groove and the first groove are aligned or offset from each other.

7. An electrode sheet as described in claim 5, wherein the second groove and the first groove have the same shape.

8. The electrode sheet according to claim 5 , wherein the second groove extends in a direction from the second side edge to the first side edge.

9. A wound battery cell comprising a separator and the electrode sheet according to any one of claims 1 to 8, the separator being disposed between two of the electrode sheets.

10. The wound battery cell of claim 9, wherein the separator is a polymer having nanoscale pores.

11. A battery comprising the wound battery cell of claim 9.

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