Battery cell structure, battery and battery module

Abstract

The utility model relates to lithium ion battery technical field especially relates to a kind of battery cell structure, battery and battery module.The battery cell structure provided by the utility model is set up empty foil area in the bending part of battery cell, to solve the lithium analysis problem of arc area.And the bending part does not contain active material layer, material layer number is less, bending difficulty is low, will not form the corner of greater bending radian, it is favorable to the miniaturization of roll core volume, can improve the energy density of battery cell whole.And corresponding protective adhesive tape is pasted on one or both of the first empty foil area and the second empty foil area, forms the protection to diaphragm, avoids the burr of current collector edge to puncture diaphragm.The utility model further provides a kind of battery and battery module.

Description

TECHNICAL FIELD

[0001] The utility model relates to lithium ion battery technical field, especially relate to a cell structure, battery and battery module. BACKGROUND

[0002] Lithium ion battery is a new type of chemical power supply with high energy density, high power density and long life, and is widely used in electric vehicles, mobile communication, portable electronic equipment and other fields. The winding cell is a common form of lithium ion battery electrode assembly, and the positive plate, negative plate and isolation film are wound together by winding machine in the manufacturing process, and the adjacent positive and negative plates are separated by the isolation film. The winding cell has the advantages of compact structure, low cost and high production efficiency, but also has the problem of lithium precipitation at the corner.

[0003] Lithium precipitation refers to the phenomenon that part of lithium ions cannot be embedded in the negative electrode material during charging of lithium ion battery, and metal lithium is formed on the surface of the negative electrode. The positive and negative plates in the arc area of the winding cell are extruded, which causes the gap between the positive and negative plates to become smaller, and the wettability or flowability of the electrolyte in the arc area is poor, which affects the embedding of lithium ions, and thus the lithium precipitation phenomenon occurs. Lithium precipitation phenomenon can cause battery performance degradation, cycle life shortening and other problems. Therefore, how to effectively avoid lithium precipitation in the arc area of the winding cell has become a technical problem to be solved by the technical personnel in the field. UTILITY MODEL CONTENT

[0004] In order to solve the problems and deficiencies in the prior art, the utility model provides a cell structure, a battery and a battery module. The cell structure in the utility model comprises a positive plate, a negative plate and a diaphragm. The positive plate and the negative plate are wound to form an arc area and a flat area, the positive plate comprises a plurality of first bending parts located in the arc area, and the negative plate comprises a plurality of second bending parts located in the arc area.

[0005] The positive plate has a first empty foil area, the first empty foil area comprises a positive current collector, the two sides of the positive current collector are not covered with a positive active material layer, and the first empty foil area is a plurality of; and the first bending part is located in the first empty foil area.

[0006] The negative plate has a second empty foil area, the second empty foil area comprises a negative current collector, the two sides of the negative current collector are not covered with a negative active material layer, and the second empty foil area is a plurality of; and the second bending part is located in the second empty foil area; the first empty foil area is pasted with a first protective adhesive tape, and / or,

[0007] The second empty foil area is pasted with a second protective adhesive tape.

[0008] Optionally, the length of the second empty foil area is 1mm-2mm smaller than the length of the adjacent first empty foil area.

[0009] Optionally, the first protective tape is less than the thickness of the positive active material layer.

[0010] Optionally, the second protective tape is less than the thickness of the negative active material layer.

[0011] Optionally, the length of the first protective tape is equal to the length of the first empty foil area.

[0012] Optionally, the width of the first protective tape is greater than the width of the positive electrode sheet.

[0013] Optionally, the length of the second protective tape is equal to the length of the second empty foil area.

[0014] Optionally, the width of the second protective tape is greater than the width of the negative electrode sheet.

[0015] Optionally, the thickness of the first protective tape is 8-16 microns; and / or,

[0016] the thickness of the second protective tape is 8-16 microns.

[0017] The utility model also provides a kind of battery, including the battery structure described in any one of the above.

[0018] The utility model also provides a kind of battery module, the battery module includes the battery described in any one of the above, the number of the battery is multiple, and multiple the battery is connected in series and / or is connected in parallel.

[0019] Compared with the prior art, the utility model has the beneficial effects that:

[0020] The current collector of the arc area does not cover the active material layer, the proportion of the flat area is increased, which can solve the lithium precipitation in the arc area, strengthen the electrical performance and safety performance of the battery cell, and will not reduce the energy density of the battery cell. Moreover, the corresponding protective tape is pasted on one or both of the first empty foil area and the second empty foil area, which forms protection for the diaphragm and avoids the diaphragm being pierced by the burrs on the edge of the current collector.

[0021] The above and other objects, advantages and features of the utility model will be more apparent to those skilled in the art from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0022] Some specific embodiments of the utility model will be described in detail hereinafter with reference to the accompanying drawings in an exemplary but not restrictive manner. The same reference signs in the drawings denote the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0023] Figure 1It is the structure schematic view of the positive plate and the negative plate of an embodiment of the utility model;

[0024] Figure 2 It is the schematic view of the cell structure of an embodiment of the utility model;

[0025] Figure 3 It is the schematic view of the local structure of an embodiment of the utility model;

[0026] Figure 4 It is the schematic view of the local structure of another embodiment of the utility model.

[0027] In the drawing: 1-cell structure, 2-circular arc area, 3-flat area;10-positive plate, 11-positive current collector, 12-positive active material layer, 13-first empty foil area, 14-first bending part, 15-first protective glue;20-negative plate, 21-negative current collector, 22-negative active material layer 22, 23-second empty foil area, 24-second bending part, 25-second protective glue;30-separator. DETAILED DESCRIPTION

[0028] The utility model embodiment will be described below Figures 1 to 4 A cell structure, a battery and a battery module are described. In the description of the embodiment, it should be understood that the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features, that is, one or more of the features. In the description of the utility model, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited. When a certain feature "includes or contains" a certain or certain features, unless otherwise specifically described, it indicates that other features and other features can be further included.

[0029] In the description of the embodiment, the description of the terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0030] For convenience of description, in this application, the positive plate and the negative plate are collectively referred to as the plate. The positive active material layer and the negative active material layer 22 are collectively referred to as the active material layer.

[0031] Figure 1 is a structure schematic view of the positive electrode sheet and the negative electrode sheet according to one embodiment of the present application. As shown in Figure 1 , in combination with Figures 2 to 4 , the present application provides an electric core structure 1, wherein the electric core structure 1 comprises a positive electrode sheet 10, a negative electrode sheet 20 and a diaphragm 30, and the positive electrode sheet 10 and the negative electrode sheet 20 are wound to form an arc region 2 and a flat region 3. The positive electrode sheet 10 comprises a plurality of first bending parts 14 located in the arc region 2, and the negative electrode sheet 20 comprises a plurality of second bending parts 24 located in the arc region 2. The positive electrode sheet 10 has a first empty foil region 13, the first empty foil region 13 comprises a positive electrode current collector 11, both sides of the positive electrode current collector 11 are not covered by a positive electrode active material layer 12, the first empty foil region 13 is a plurality of, and the first bending part 14 is located in the first empty foil region 13. The negative electrode sheet 20 has a second empty foil region 23, the second empty foil region 23 comprises a negative electrode current collector 21, both sides of the negative electrode current collector 21 are not covered by a negative electrode active material layer 22, the second empty foil region 23 is a plurality of, and the second bending part 24 is located in the second empty foil region 23. A first protective adhesive tape 15 is attached on the first empty foil region 13.

[0032] Specifically, when the electric core structure 1 is made, the length of the flat region 3 and the length of the arc region 2 of each circle of the positive electrode sheet 10 of the electric core structure 1 are calculated. According to the calculation result, the positive electrode current collector 11 is covered, or according to the calculation result, the covered positive electrode sheet 10 is etched to form the first empty foil region 13, a plurality of first empty foil regions 13 are arranged at intervals, and the first protective adhesive tape 15 is attached on the first empty foil region 13. Correspondingly, the length of the flat region 3 and the length of the arc region 2 of each circle of the negative electrode sheet 20 of the electric core structure 1 are calculated. According to the calculation result, the negative electrode current collector 21 is covered, or according to the calculation result, the covered negative electrode sheet 20 is etched to form the second empty foil region 23, a plurality of second empty foil regions 23 are arranged at intervals. When the positive electrode sheet 10, the negative electrode sheet 20 and the diaphragm 30 are wound to prepare the electric core, the first empty foil region 13 and the second empty foil region 23 are arranged correspondingly. And the first bending part 14 is located in the first empty foil region 13, and the second bending part 24 is correspondingly located in the second empty foil region 23.

[0033] In this embodiment, the first bending portion 14 does not cover the positive electrode active material layer 12, and the positive electrode current collector 11 is not covered by the positive electrode active material layer 12 here. The second bending portion 24 does not cover the negative electrode active material layer 22, and the negative electrode current collector 21 is not covered by the negative electrode active material layer 22 here. Therefore, lithium plating will not occur in the arc region 2, thereby improving the electrical performance and safety of the cell. At the same time, the arc region 2 does not have an active material layer, and its thickness is thinner than that of the flat region 3, making bending easier and avoiding the formation of corners with large bending arcs. The length range of the arc region 2 is reduced, while the length ratio of the flat region 3 is increased. The utilization rate of corner and side space of the cell structure 1 is improved, which can improve the energy density of the cell structure 1. A first protective adhesive paper 15 is attached to the first empty foil region 13 to form protection for the separator 30 corresponding to the first empty foil region 13, preventing burrs on the edge of the positive electrode current collector 11 from piercing the separator 30.

[0034] In some other embodiments of this invention, a second protective adhesive paper 25 is affixed to the second empty foil area 23. The second protective adhesive paper 25 forms a protection for the diaphragm 30 corresponding to the second empty foil area 23, preventing burrs from the edge of the negative electrode current collector 21 from piercing the diaphragm 30.

[0035] In some other embodiments of this utility model, a first protective adhesive paper 15 is affixed to the first empty foil area 13, and a second protective adhesive paper 25 is affixed to the second empty foil area 23. The provision of the first protective adhesive paper 15 and the second protective adhesive paper 25 further enhances the protective effect.

[0036] like Figure 3 and Figure 4 As shown, in some embodiments of this utility model, the length of the second empty foil area 23 is 1 mm to 2 mm shorter than the length of the adjacent first empty foil area 13.

[0037] Specifically, along the winding direction of the electrode sheet, the length of the first empty foil region 13 is 1 mm to 2 mm longer than the length of the adjacent second empty foil region 23. That is, along the winding direction of the electrode sheet, a portion of the first empty foil region 13 is opposite to the negative electrode sheet 20 covered with the negative electrode active material layer 22. Preferably, the length of the first empty foil region 13 is 1.5 mm longer than the length of the adjacent second empty foil region 23.

[0038] In this embodiment, the negative electrode active material layer 22 has a certain margin relative to the positive electrode active material layer 12. This ensures the safety of lithium plating without reducing the battery energy density due to excessive margin area.

[0039] In some embodiments of this utility model, the first protective adhesive paper 15 is less than the thickness of the positive electrode active material layer 12. Specifically, the first protective adhesive paper 15 is attached to the first empty foil area 13 to form protection for the separator 30 corresponding to the first empty foil area 13, preventing burrs on the edge of the positive electrode current collector 11 from piercing the separator 30.

[0040] In some embodiments of the utility model, the width of the first protective adhesive paper 15 is greater than the width of the positive plate 10. In the cutting process of the positive current collector 11, burrs will be generated at the cutting position. If the burrs pierce the diaphragm 30, the negative plate 20 will be contacted, which will cause the battery short circuit, and further can cause the battery overheat, liquid leakage and even explosion and other serious consequences; the width of the first protective adhesive paper 15 is greater than the width of the positive plate 10, which can cover the burrs on the positive current collector 11, avoid the burrs piercing the diaphragm 30 to cause the battery short circuit, and improve the battery safety.

[0041] In some embodiments of the utility model, the length of the first protective adhesive paper 15 is equal to the length of the first empty foil area 13. Specifically, along the winding direction of the plate, the length of the first protective adhesive paper 15 is equal to the length of the first empty foil area 13; the length of the first protective adhesive paper 15 is equal to the length of the first empty foil area 13, which can not only protect the diaphragm 30 corresponding to the first empty foil area 13 and avoid the burrs on the positive current collector 11 piercing the diaphragm 30, but also will not cover the positive active material layer 12 due to the excessive length to reduce the energy density of the battery. It should be noted that in order to control the length of the first protective adhesive paper 15 to be equal to the length of the first empty foil area 13, laser die cutting adhesive paper can be used, and visual positioning can be used to the arc empty foil area.

[0042] In some embodiments of the utility model, the thickness of the first protective adhesive paper 15 is 8-16 mu m. Specifically, the thickness of the first protective adhesive paper 15 can be any value between 8-16 mu m, such as 8 mu m, 10 mu m, 12.5 mu m, 14 mu m, 16 mu m and the like. Preferably, the thickness of the first protective adhesive paper 15 is 12 mu m.

[0043] If the thickness of the first protective adhesive paper 15 is too thin, the burrs on the positive current collector 11 cannot isolate the diaphragm 30 to form protection; if the thickness of the first protective adhesive paper 15 is too thick, the thickness of the first bending part 14 is increased, the width of the arc area 2 is increased, the proportion of the straight area 3 is reduced, and the energy density of the battery is reduced. The thickness of the first protective adhesive paper 15 is 8-16 mu m, which can not only isolate the burrs on the positive current collector 11 to form protection to the diaphragm 30, but also will not significantly affect the energy density of the battery.

[0044] In some embodiments of the utility model, the width of the second protective adhesive paper 25 is greater than the width of the negative plate 20. That is, the second protective adhesive paper 25 can completely cover the second empty foil area 23.

[0045] In the cutting process of the negative current collector 21, burrs are generated at the cutting position. If the burrs pierce the separator 30 and contact the positive electrode sheet 10, a short circuit of the battery is caused, which may further lead to serious consequences such as overheating, leakage and even explosion of the battery. The second protective adhesive tape 25 has a width greater than that of the negative electrode sheet 20, and can cover the burrs on the negative current collector 21 to avoid the burrs piercing the separator 30 and causing a short circuit of the battery, thereby improving the safety of the battery.

[0046] In some embodiments of the present application, the length of the second protective adhesive tape 25 is equal to the length of the second empty foil area 23. Specifically, along the winding direction of the electrode sheet, the length of the second protective adhesive tape 25 is equal to the length of the second empty foil area 23. The length of the second protective adhesive tape 25 being equal to the length of the second empty foil area 23 can not only protect the separator 30 corresponding to the second empty foil area 23 from being pierced by the burrs on the negative current collector 21, but also will not reduce the energy density of the battery due to the overlong coverage of the negative active material layer 22.

[0047] In some embodiments of the present application, the thickness of the second protective adhesive tape 25 is 8-16 μm. Specifically, the thickness of the second protective adhesive tape 25 can be any value between 8 μm and 16 μm, such as 8 μm, 10 μm, 12.5 μm, 14 μm, 16 μm, and the like. Preferably, the thickness of the second protective adhesive tape 25 is 12 μm.

[0048] If the thickness of the second protective adhesive tape 25 is too thin, it cannot isolate the burrs on the negative current collector 21 from the separator 30. If the thickness of the second protective adhesive tape 25 is too thick, it will increase the thickness of the second bending portion 24 and the width of the circular arc area 2, and reduce the proportion of the flat area 3, thereby reducing the energy density of the battery. The thickness of the second protective adhesive tape 25 is 8-16 μm, which can not only isolate the burrs on the negative current collector 21 from the separator 30, but also will not significantly affect the energy density of the battery.

[0049] The present application also provides a battery, which comprises the cell structure 1 according to any one of the above embodiments. That is, the cell structure 1 described in any one of the above embodiments forms a battery after encapsulation. The circular arc area 2 of the battery in the present embodiment does not produce lithium precipitation and is not counted as the energy density of the battery.

[0050] The present application also provides a battery module, which comprises a plurality of batteries according to any one of the above embodiments, and the plurality of batteries are connected in series.

[0051] The battery module of the present application comprises a plurality of batteries, which effectively increases the capacity of the battery module and expands the application range of the battery module. Those skilled in the art can select an appropriate number according to the application and capacity of the battery module.

[0052] The utility model further provides a battery module, the battery module includes a plurality of batteries in any one embodiment above, and the plurality of batteries are in parallel.

[0053] In the embodiment, the plurality of batteries are in parallel, the battery module can obtain higher battery capacity, and when one battery is exhausted or fails, the other batteries in the battery module can continue to supply power, thereby ensuring continuous operation of the electrical equipment.

[0054] In use, the battery module is designed according to actual conditions, so that the battery module has higher energy transmission efficiency.

[0055] The above-mentioned battery can be applied to any electrical equipment known in the prior art. The electrical equipment can include, but is not limited to, an electronic cigarette, an electronic vapor device, a wireless earphone, a sweeping robot, a unmanned aerial vehicle, a notebook computer, a pen input type computer, a mobile computer, an electronic book player, a portable telephone, a portable facsimile machine, a portable copying machine, a portable printer, a head-mounted stereo earphone, a video recorder, a liquid crystal television, a portable cleaner, a portable CD machine, a mini disc, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, an automobile, a motorcycle, a power-assisted bicycle, a bicycle, a lighting appliance, a toy, a game machine, a clock, a power tool, a flashlight, a camera, a household large storage battery and a lithium ion capacitor, etc.

[0056] The above-mentioned battery module can be applied to any electrical equipment known in the prior art.

[0057] At this point, those skilled in the art should realize that, although the utility model has been shown and described in detail herein, many other variants or modifications conforming to the principles of the utility model can be directly determined or deduced according to the disclosure of the utility model without departing from the spirit and scope of the utility model. Therefore, the scope of the utility model should be understood and recognized as covering all these other variants or modifications.

Claims

1. A battery cell structure, said battery cell structure comprising a positive electrode, a negative electrode, and a separator, characterized in that, The positive electrode and the negative electrode are wound to form an arc region and a straight region. The positive electrode includes a plurality of first bends located in the arc region, and the negative electrode includes a plurality of second bends located in the arc region. The positive electrode sheet has a first empty foil area, which includes a positive electrode current collector. Neither side of the positive electrode current collector is covered with a positive electrode active material layer. There are multiple first empty foil areas. The first bending portion is located in the first empty foil area. The negative electrode sheet has a second empty foil area, which includes a negative electrode current collector. Neither side of the negative electrode current collector is covered with a negative electrode active material layer. There are multiple second empty foil areas. The second bending portion is located in the second empty foil area. The first empty foil area is covered with a first protective adhesive film, and / or, A second protective adhesive paper is affixed to the second empty foil area.

2. The cell structure according to claim 1, characterized in that, The length of the second empty foil area is 1 mm to 2 mm shorter than the length of the adjacent first empty foil area.

3. The cell structure according to claim 1, characterized in that, The thickness of the first protective adhesive paper is smaller than that of the positive electrode active material layer.

4. The cell structure according to claim 1 or 3, characterized in that, The second protective adhesive paper is thinner than the negative electrode active material layer.

5. The cell structure according to claim 3, characterized in that, The length of the first protective adhesive paper is equal to the length of the first empty foil area; and / or, The width of the first protective adhesive paper is greater than the width of the positive electrode sheet.

6. The cell structure according to claim 4, characterized in that, The length of the second protective film is equal to the length of the second empty foil area; and / or, The width of the second protective adhesive paper is greater than the width of the negative electrode sheet.

7. The cell structure according to claim 3, characterized in that, The thickness of the first protective adhesive paper is 8μm~16μm.

8. The cell structure according to claim 4, characterized in that, The thickness of the second protective adhesive paper is 8μm~16μm.

9. A battery comprising the cell structure as described in any one of claims 1 to 8.

10. A battery module, characterized in that, Includes the battery as described in claim 9, wherein there are multiple batteries, and the multiple batteries are connected in series and / or in parallel.

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