Winding battery cell and battery

Abstract

In order to solve the problems that in the prior art, due to the fact that adhesive paper is pasted at the burr edge position of a positive plate, the thickness of the positive plate is too large, short circuit is caused, and the volume energy density of the battery is not favorably improved, the utility model provides a winding battery cell and a battery, the winding battery cell comprises the positive plate, the adhesive paper, a negative plate and a diaphragm, the positive plate, the negative plate and the diaphragm are wound to form a wound cell; the positive plate comprises an empty foil area and a coating area, the end part of the positive plate in the winding battery cell is taken as the head part of the positive plate, the end part of the positive plate outside the winding battery cell is taken as the tail part of the positive plate, the empty foil area is arranged at the winding head part of the positive plate, the coating area extends from the edge of the empty foil area to the tail part of the positive plate, and the adhesive paper covers the empty foil area. According to the winding cell provided by the utility model, the gummed paper covers the empty foil area of the winding head, and the gummed paper covers the burr edge of the head of the cut positive plate, so that the problems of short circuit and safety of the battery caused by the fact that the burr edge punctures and damages a diaphragm in the winding cell are solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery winding manufacturing, and specifically relates to a winding battery core and a battery. Background Art

[0002] The assembly of conventional cylindrical batteries generally includes winding and lamination processes. Cylindrical batteries mainly include positive electrode sheets, diaphragms, negative electrode sheets and other structural parts. When the battery cell in the cylindrical battery is a wound battery cell, the positive electrode sheet, negative electrode sheet and diaphragm are wound into a battery cell. In addition, since the electrode sheets are continuously produced in the electrode sheet production process, the electrode sheets need to be cut according to the actual usage during the preparation of the battery cell. Due to the influence of cutting, the electrode sheets will form burr edges. After winding, as the electrode sheets expand and contract during the charging and discharging process of the battery, the burr edges of the electrode sheets are easy to pierce the diaphragm and cause In order to solve the problem of battery short circuit, in the prior art, adhesive paper or tape is usually pasted on the burr edge of the positive electrode sheet, and one part of the adhesive paper or tape is pasted on the collector in the empty foil area and the other part is pasted on the coating area coated with the active material. Although this method can eliminate the influence of the burr edge, since the tape also covers the active material layer in the coating area, the thickness of the positive electrode sheet is too thick when it is wound, and the short circuit problem is still easy to occur, which poses a great safety hazard and is not conducive to the improvement of the battery volume energy density. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a wound battery cell and a battery in view of the problem in the prior art that adhesive tape is pasted on the burr edge of the positive electrode sheet, making the electrode sheet too thick, causing a short circuit and being unfavorable for improving the volume energy density of the battery.

[0004] The technical solution adopted by the utility model to solve the above technical problems is as follows:

[0005] Provided is a wound battery cell, comprising a positive electrode sheet, adhesive tape, a negative electrode sheet and a separator, wherein the separator is located between the positive electrode sheet and the negative electrode sheet, and the positive electrode sheet, the negative electrode sheet and the separator are wound to form a wound battery cell; the positive electrode sheet comprises a hollow foil area and a coated area, the end of the positive electrode sheet located inside the wound battery cell is the head of the positive electrode sheet, and the end of the positive electrode sheet located outside the wound battery cell is the tail of the positive electrode sheet, the hollow foil area is arranged at the head position of the wound positive electrode sheet, the coated area extends from the edge of the hollow foil area to the tail direction of the positive electrode sheet, and the adhesive tape covers the hollow foil area.

[0006] Optionally, the empty foil area and the coated area are provided on both side surfaces of the positive electrode sheet, and the adhesive tape is attached to both sides of the positive electrode sheet.

[0007] Optionally, both sides of the projection of the adhesive tape on the positive electrode sheet extend out of both sides of the width direction of the empty foil area to form extension parts, and the extension parts of the two adhesive tapes located on both sides of the positive electrode sheet are attached to each other.

[0008] Optionally, the corner position of the extension portion located at the head of the positive electrode sheet is rounded.

[0009] Optionally, the corner position of the head of the positive electrode sheet is rounded.

[0010] Optionally, the empty foil area has a length of 1 to 3 mm.

[0011] Optionally, the adhesive tape has a length of 1 to 3 mm.

[0012] Optionally, the adhesive tape has a thickness of 12 to 25 μm.

[0013] Optionally, the wound battery cell further includes a positive electrode tab and a negative electrode tab, wherein the positive electrode tab is connected to the positive electrode sheet, and the negative electrode tab is connected to the negative electrode sheet.

[0014] On the other hand, the utility model provides a battery, including a cover plate, a battery shell and the wound battery cell described in the item, wherein the battery shell is a semi-closed shell with an opening on one side, the battery cell is placed inside the battery shell, and the cover plate closes the opening of the battery shell.

[0015] The wound battery cell provided by the utility model is obtained by a winding process from the positive electrode sheet, the negative electrode sheet and the diaphragm, the positive electrode sheet includes a hollow foil area and a coated area, and the hollow foil area is arranged at the head of the positive electrode sheet being wound, and the hollow foil area is covered with adhesive tape, that is, by covering the starting position of the positive electrode sheet being wound with adhesive tape, the burr edge of the positive electrode sheet after being cut is covered with the adhesive tape, thereby facilitating improvement of battery short circuit and safety problems caused by the burr edge piercing and damaging the diaphragm in the wound battery cell. In addition, the adhesive tape described in the present application only covers the position of the hollow foil area at the winding head, compared with the operation of directly covering the coating area with adhesive tape in the prior art, it is conducive to reducing the thickness of the starting position of the winding of the positive electrode sheet after being covered with adhesive tape, avoiding poor winding core caused by excessive thickness when the positive electrode sheet is wound, and at the same time improving the volume energy density inside the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of the positive electrode sheet provided by the utility model;

[0017] Figure 2 It is a schematic diagram of the structure of the positive electrode sheet covering adhesive tape provided by the utility model.

[0018] The reference numerals in the drawings of the specification are as follows:

[0019] 1. Positive electrode; 11. Empty foil area; 12. Coating area; 2. Adhesive tape; 3. Extension part. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects solved by the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0021] In the description of the present invention, it should be understood that the terms "longitudinal", "radial", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] The utility model embodiment provides a wound battery cell, comprising a positive electrode sheet 1, adhesive tape 2, a negative electrode sheet and a separator, wherein the separator is located between the positive electrode sheet 1 and the negative electrode sheet, and the positive electrode sheet 1, the negative electrode sheet and the separator are wound to form a wound battery cell; the positive electrode sheet 1 comprises a hollow foil area 11 and a coating area 12, the end of the positive electrode sheet 1 located inside the wound battery cell is the head of the positive electrode sheet 1, and the end of the positive electrode sheet 1 located outside the wound battery cell is the tail of the positive electrode sheet 1, the hollow foil area 11 is arranged at the head position of the wound positive electrode sheet 1, the coating area 12 extends from the edge of the hollow foil area 11 to the tail direction of the positive electrode sheet 1, and the adhesive tape 2 covers the hollow foil area 11.

[0024] The wound battery cell provided by the utility model is obtained by a winding process of the positive electrode sheet 1, the negative electrode sheet and the diaphragm, the positive electrode sheet 1 comprising an empty foil area 11 and a coating area 12, and the empty foil area 11 is arranged at the head of the winding of the positive electrode sheet 1, and the empty foil area 11 is covered with adhesive tape 2, that is, by covering the adhesive tape 2 at the starting position of the winding of the positive electrode sheet 1, the adhesive tape 2 is used to cover the burr edge of the positive electrode sheet 1 after cutting, thereby helping to improve the battery short circuit and safety problems caused by the burr edge piercing and damaging the diaphragm in the wound battery cell. In addition, the adhesive tape 2 described in the present application only covers the position of the empty foil area 11 at the winding head, compared with the operation in the prior art where the adhesive tape 2 directly covers the coating area 12, it is helpful to reduce the thickness of the starting position of the winding of the positive electrode sheet 1 after being covered with the adhesive tape 2, avoiding the poor winding core caused by the excessive thickness when the positive electrode sheet 1 is wound, and at the same time improving the volume energy density inside the battery.

[0025] In one embodiment, the empty foil area 11 and the coating area 12 are disposed on both side surfaces of the positive electrode sheet 1 , and the adhesive tape 2 is attached to both sides of the positive electrode sheet 1 .

[0026] Specifically, sticking adhesive tape 2 on both sides of the positive electrode sheet 1 is conducive to fully covering the empty foil area 11, and using the adhesive tape 2 to cover the burr edges of the positive electrode sheet 1 after cutting, which is conducive to improving the battery short circuit and safety problems caused by the burr edges piercing and damaging the diaphragm in the wound battery cell.

[0027] In one embodiment, both sides of the projection of the adhesive tape 2 on the positive electrode sheet 1 extend out of the width direction of the empty foil area 11 to form extension portions 3, and the extension portions 3 of the two adhesive tapes 2 located on both sides of the positive electrode sheet 1 are bonded to each other.

[0028] Specifically, the extension portions 3 of the two adhesive tapes 2 located on both sides of the positive electrode sheet 1 are bonded to each other. This arrangement is conducive to forming a completely covered bonding portion on the empty foil area 11, so that the adhesive tape 2 can better cover the empty foil area 11, thereby effectively solving the adverse effects of the burr edge of the head of the positive electrode sheet 1 on the formed wound battery cell.

[0029] In one embodiment, the corner position of the extension portion 3 located at the head of the positive electrode sheet 1 is rounded.

[0030] In one embodiment, the corner position of the head of the positive electrode sheet 1 is rounded.

[0031] It should be noted that in the preparation process of the wound battery cell, the positive electrode sheet 1 is usually placed in place first, and then the separator and the negative electrode sheet are added in a certain order, and the wound battery cell is prepared by a winding process. In the early preparation of the positive electrode sheet 1, the positive and negative active materials need to be coated on the current collector, and then cut into a specified size after drying. There is a risk that the head of the cut electrode sheet (the starting point of winding) may have a sharp corner that pierces the separator.

[0032] Specifically, the present application sets the corner position of the head of the positive electrode sheet 1 to a rounded corner, which can avoid damage to the diaphragm by the head of the positive electrode sheet 1 after cutting, prevent internal short circuit of the battery, and ensure the stability of the battery structure. In addition, the corner position of the extension portion 3 located at the head of the positive electrode sheet 1 is set to a rounded corner, so that the adhesive tape 2 can better fit the positive electrode head.

[0033] In one embodiment, the length of the empty foil area 11 is 1 to 3 mm.

[0034] Specifically, the head position of the positive electrode sheet 1 is set as an empty foil area 11. After the adhesive tape 2 is subsequently pasted, compared with the prior art of directly pasting the adhesive tape 2 on the coating area 12, the thickness of the head of the positive electrode sheet 1 can be well controlled to avoid adverse reactions in the prepared wound battery cell caused by excessive thickness, and the internal space of the battery can be saved, which is beneficial to improve the volume energy density inside the battery; in addition, the length of the empty foil area 11 can be specifically set according to the length of the positive electrode sheet 1 first rolled during winding. Specifically, the length of the empty foil area 11 can be 1mm, 1.5mm, 2mm, 2.5mm or 3mm.

[0035] In one embodiment, the adhesive tape 2 has an adhesive length of 1 to 3 mm.

[0036] The length direction of the empty foil area 11 is the length direction of the adhesive tape 2. The adhesive length of the adhesive tape 2 needs to be consistent with the length of the empty foil area 11 to ensure that the adhesive tape 2 can completely cover the empty foil area 11, and then cover the burr edge of the head of the positive electrode sheet 1; specifically, the adhesive length of the adhesive tape 2 can be 1mm, 1.5mm, 2mm, 2.5mm or 3mm.

[0037] In one embodiment, the adhesive tape 2 has a thickness of 12-25 μm.

[0038] During the manufacturing process of wound battery cells, under normal circumstances, the length and width of the negative electrode sheet should be larger than the positive electrode sheet 1 to prevent short circuits. If the winding head is too thick, the negative electrode sheet may not be able to completely cover the positive electrode sheet 1, thereby increasing the risk of short circuits. In addition, during the winding process, the diaphragm needs to completely wrap the negative electrode sheet to prevent short circuits caused by direct contact between the positive and negative electrodes. If the winding head is too thick, the diaphragm may not be placed correctly, thereby affecting the normal charging and discharging functions of the battery. In addition, a winding head that is too thick may cause the battery volume to increase without a corresponding increase in battery capacity, thereby reducing the battery's energy density.

[0039] Specifically, on the basis of ensuring that the adhesive tape 2 can completely cover the empty foil area 11 and the stress generated during winding will not tear the adhesive tape 2, the thickness of the adhesive tape 2 should be as thin as possible to avoid the adverse effect of the thickness of the winding head of the positive electrode sheet 1 being too thick on the prepared wound battery cell.

[0040] In one embodiment, the wound battery cell further includes a positive electrode tab and a negative electrode tab, wherein the positive electrode tab is connected to the positive electrode sheet 1 , and the negative electrode tab is connected to the negative electrode sheet.

[0041] Specifically, the positive electrode sheet 1 is connected to the positive electrode ear, and the negative electrode sheet is connected to the negative electrode ear. The current can be conducted from the positive electrode sheet 1 or the negative electrode sheet to other electronic components of the battery through the positive electrode ear and the negative electrode ear, thereby reducing the connection impedance without reducing the energy density of the battery.

[0042] In one embodiment, the positive electrode sheet 1 is made of copper foil, and the negative electrode sheet is made of copper foil.

[0043] In one embodiment, the membrane is a polyethylene film, a polypropylene film or a nylon film.

[0044] As one of the key components of the battery, the separator mainly plays the role of isolating the positive and negative electrodes in the battery to ensure that there is no physical contact and short circuit between the positive and negative electrodes.

[0045] Specifically, the diaphragm may also be a composite diaphragm, which includes but is not limited to a double-layer PP / PE diaphragm, a double-layer PP / PP diaphragm and a three-layer PP / PE / PP diaphragm.

[0046] In another embodiment, the present application provides a battery, including a cover plate, a battery shell and the wound battery cell, wherein the battery shell is a semi-enclosed shell with an opening on one side, the battery cell is placed inside the battery shell, and the cover plate closes the opening of the battery shell.

[0047] Specifically, the wound battery cell is loaded into the battery case from the opening position of the battery case, and the electrolyte is injected into the inner cavity of the battery case through the injection hole. After the injection or formation is completed, the injection port is closed, and finally the cover plate is used for packaging to obtain an internally closed and fully assembled battery.

[0048] Specifically, in a preferred embodiment, the battery housing is a cylindrical housing.

[0049] In one embodiment, the cover plate is made of aluminum and its alloys, magnesium and its alloys, iron and its alloys, nickel and its alloys, or copper and its alloys.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A wound battery cell, characterized in that: It includes a positive electrode sheet, adhesive tape, a negative electrode sheet and a separator, wherein the separator is located between the positive electrode sheet and the negative electrode sheet, and the positive electrode sheet, the negative electrode sheet and the separator are wound to form a wound battery cell; the positive electrode sheet includes a hollow foil area and a coating area, the end of the positive electrode sheet located inside the wound battery cell is the head of the positive electrode sheet, and the end of the positive electrode sheet located outside the wound battery cell is the tail of the positive electrode sheet, the hollow foil area is arranged at the head position of the wound positive electrode sheet, the coating area extends from the edge of the hollow foil area to the tail direction of the positive electrode sheet, and the adhesive tape covers the hollow foil area.

2. A wound battery cell according to claim 1, characterized in that: The empty foil area and the coating area are arranged on both side surfaces of the positive electrode sheet, and the adhesive tape is attached to both sides of the positive electrode sheet.

3. A wound battery cell according to claim 2, characterized in that: Both sides of the projection of the adhesive tape on the positive electrode sheet extend out of both sides of the width direction of the empty foil area to form extension parts, and the extension parts of the two adhesive tapes located on both sides of the positive electrode sheet are attached to each other.

4. A wound battery cell according to claim 3, characterized in that: The corner position of the extension portion located at the head of the positive electrode sheet is rounded.

5. A wound battery cell according to claim 1, characterized in that: The corner position of the head of the positive electrode sheet is rounded.

6. A wound battery cell according to claim 1, characterized in that: The length of the empty foil area is 1 to 3 mm.

7. A wound battery cell according to claim 1, characterized in that: The adhesive tape has a length of 1 to 3 mm.

8. A wound battery cell according to claim 1, characterized in that: The adhesive tape has a thickness of 12 to 25 μm.

9. A wound battery cell according to claim 1, characterized in that: The wound battery cell further includes a positive electrode ear and a negative electrode ear, wherein the positive electrode ear is connected to the positive electrode sheet, and the negative electrode ear is connected to the negative electrode sheet.

10. A battery, characterized in that: The invention comprises a cover plate, a battery shell and the wound battery cell according to any one of claims 1 to 9, wherein the battery shell is a semi-enclosed shell with an opening on one side, the battery cell is placed inside the battery shell, and the cover plate closes the opening of the battery shell.

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