A method for compensating for thinned areas in lithium-ion batteries and cells.

Abstract

This invention discloses a method for compensating for thinned areas in lithium-ion batteries and battery cells, belonging to the field of lithium-ion battery technology. The lithium-ion battery includes a battery cell and high-temperature tape. The high-temperature tape is adhered to the thinned area of ​​the battery cell. The width, length, and thickness of the high-temperature tape are determined based on the width, length, and collapse depth of the thinned area, where B = b - 2 mm, and the thickness H of the high-temperature tape is greater than or equal to the collapse depth h of the thinned area. Specifically, when a < 10 mm, A = 1.5a; when 10 mm ≤ a < 25 mm, the width A = 1.2a. Compensating for the thickness of the thinned area of ​​the battery cell by adhering the high-temperature tape is simple and easy to implement. This method not only reduces the electrolyte content but also increases the energy density of the battery cell, improving its cycle performance and safety.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and in particular to a method for compensating for thinned areas in lithium-ion batteries and cells. Background Technology

[0002] As user demands continue to increase, lithium-ion batteries have been widely used in all aspects of life, and the requirements for lithium-ion batteries are also getting higher and higher.

[0003] As the capacity and energy density of lithium-ion batteries increase, the number of layers in the cell has increased from a few to dozens, or even hundreds. Due to the presence of thinning zones, the thickness difference between the edge and center of the cell is also increasing, from a few micrometers to tens of micrometers, or even reaching the millimeter level. This thickness difference leads to inconsistent compaction density of the electrode sheets and inconsistent distances between the positive and negative electrode sheets in the core, thus affecting battery cycle life and safety performance. Because the compaction density of the thinning zones is low and the gap between the positive and negative electrode sheets in the thinning zones is large, a large amount of electrolyte is required. The common method is to increase the electrolyte content to compensate, reduce polarization, and improve cycle performance. This approach not only results in a loss of gravimetric energy density but also only temporarily improves cycle performance. After the electrolyte is consumed, the cycle performance will still decline rapidly, and there is a risk of lithium plating.

[0004] Therefore, there is an urgent need to provide a compensation method for the thinned area of ​​lithium-ion batteries and cells to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for compensating for the thinned area of ​​a lithium-ion battery cell, thereby reducing the electrolyte content, increasing the energy density of the cell, and improving the cycle performance and safety performance of the cell.

[0006] To achieve the above objectives, the following technical solution is provided:

[0007] A lithium-ion battery, comprising:

[0008] The battery cell has a central region and thinning regions located on both sides of the central region, wherein the width of the thinning regions is a, the length is b, and the collapse depth is h;

[0009] High-temperature tape is applied to the thinned area, and the width of the high-temperature tape is A, the length is B, and the thickness is H; wherein, B = b - 2 mm, and H ≥ h; wherein, when a < 10 mm, A = 1.5a; when 10 mm ≤ a < 25 mm, A = 1.2a.

[0010] A method for compensating for the thinned area of ​​a battery cell, used to compensate for the collapse depth of the thinned area of ​​a lithium-ion battery cell relative to the middle region of the cell, as described above, includes the following steps:

[0011] Obtain the width 'a' and the collapse depth 'h' of the thinned region of the battery cell;

[0012] Based on the width a and the collapse depth h of the thinned area, the width A and thickness H of the high-temperature tape are determined; where H ≥ h; where, when a < 10 mm, A = 1.5a; when 10 mm ≤ a < 25 mm, A = 1.2a;

[0013] The high-temperature tape is applied to the thinned area.

[0014] As an optional method for compensating the thinned area of ​​the battery cell, during the process of obtaining the width a and the collapse depth h of the thinned area of ​​the battery cell, the length b of the thinned area of ​​the battery cell is also obtained, wherein the length B of the high-temperature tape is b-2mm.

[0015] As an optional method for compensating the thinned area of ​​the battery cell, the thickness of the high-temperature tape is H = 1.2h.

[0016] As an optional method for compensating the thinned area of ​​the battery cell, the thickness of the high-temperature tape is H = 1.5h.

[0017] As an optional method for compensating the thinned area of ​​the battery cell, the high-temperature tape is made of polyimide.

[0018] As an optional method for compensating the thinned area of ​​the battery cell, the thickness H of the high-temperature tape is 5um-12um.

[0019] As an optional method for compensating the thinned area of ​​the battery cell, the thickness H of the high-temperature tape is 8um-10um.

[0020] As an optional method for compensating the thinned area of ​​the battery cell, the high-temperature tape has a width A of 12 mm, a thickness H of 8 μm, and a length B of 319 mm.

[0021] As an optional method for compensating the thinned area of ​​the battery cell, the high-temperature tape has a width A of 18 mm, a thickness H of 8 μm, and a length B of 352 mm.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] The method for compensating the thinned area of ​​a battery cell provided by this invention determines the width A and thickness H of a high-temperature adhesive tape based on the width 'a' and the collapse depth 'h' of the thinned area; and then adheres the high-temperature adhesive tape to the thinned area. Wherein, thickness H ≥ collapse 'h'; where, when width 'a' < 10 mm, width A = 1.5a; when 10 mm ≤ a < 25 mm, width A = 1.2a. Compensating for the thickness of the thinned area of ​​the battery cell by adhering high-temperature adhesive tape is simple and easy to implement. It not only reduces the electrolyte content but also increases the energy density of the battery cell, improving its cycle performance and safety performance.

[0024] The lithium-ion battery provided by this invention uses high-temperature tape adhered to the thinned area of ​​the cell. The width, length, and thickness of the high-temperature tape are determined based on the width, length, and collapse depth of the thinned area, where B = b - 2 mm, and the thickness H of the high-temperature tape is greater than or equal to the collapse depth h of the thinned area. Specifically, when a < 10 mm, A = 1.5a; when 10 mm ≤ a < 25 mm, the width A = 1.2a. This reduces the electrolyte content, increases the energy density, and improves the cycle performance and safety performance of the lithium-ion battery. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0026] Figure 1 This is a flowchart of the compensation method for the thinned area of ​​the battery cell in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the battery cell structure in an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of high-temperature tape being adhered to the thinning area of ​​the battery cell in an embodiment of the present invention;

[0029] Figure 4 This is a top view of high-temperature tape being applied to the thinned area of ​​the battery cell in an embodiment of the present invention;

[0030] Figure 5 This is a comparison chart of the cycle performance tests of cell one and cell two in an embodiment of the present invention;

[0031] Figure 6 This is a comparison chart of the cycle performance tests of battery cells three and four in an embodiment of the present invention.

[0032] Figure label:

[0033] 1. Battery cell; 2. High-temperature tape;

[0034] 11. Thinning area; 12. Intermediate area; 13. Electrode tab. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0037] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0038] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0039] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0041] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0042] Due to the presence of thinning zones, the thickness difference between the cell's edge and center areas increases significantly, from a few micrometers to tens of micrometers, and even reaching the millimeter level. This thickness difference leads to inconsistent electrode compaction density and inconsistent distances between the positive and negative electrodes within the core, thus affecting battery cycle life and safety. Because the thinning zones have low compaction density and large gaps between the positive and negative electrodes, a large amount of electrolyte is required. Currently, a common method is to increase the electrolyte content to compensate, reduce polarization, and improve cycle performance. However, this approach not only sacrifices gravimetric energy density but also only temporarily improves cycle performance. Once the electrolyte is consumed, the cycle performance will still decline rapidly, and there is a risk of lithium plating.

[0043] To reduce electrolyte content, increase cell energy density, and improve cell cycle performance and safety, this embodiment provides a method for compensating for thinned areas in the cell. The following is a detailed explanation. Figures 1 to 6 The specific content of this embodiment will be described in detail.

[0044] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the compensation method for the thinned area of ​​the battery cell provided in this embodiment is used to compensate for the collapse depth of the thinned area 11 of the battery cell 1 relative to the middle region 12 of the battery cell 1. Motor tabs 13 are welded on both sides of the battery cell 1. The compensation method for the thinned area of ​​the battery cell includes the following steps:

[0045] Obtain the width a and collapse depth h of the thinned region 11 of cell 1;

[0046] Based on the width a and the collapse depth h of the thinned area 11, the width A and thickness H of the high-temperature tape 2 are determined; wherein, the thickness H of the high-temperature tape 2 is greater than or equal to the collapse depth h of the thinned area 11; wherein, when the width a of the thinned area 11 is less than 10 mm, the width A of the high-temperature tape 2 is 1.5a; when 10 mm ≤ a < 25 mm, the width A of the high-temperature tape 2 is 1.2a.

[0047] Apply high-temperature tape 2 to the thinned area 11.

[0048] In summary, the cell thinning compensation method provided in this embodiment determines the width A and thickness H of the high-temperature tape based on the width a and collapse depth h of the thinned area 11 of the cell 1; and then pastes the high-temperature tape onto the thinned area. Wherein, thickness H ≥ collapse h; where, when width a < 10mm, width A = 1.5a; when 10mm ≤ a < 25mm, width A = 1.2a. Compensating for the thickness of the thinned area 11 of the cell 1 by pasting high-temperature tape is simple and easy to implement; it not only reduces the electrolyte content but also increases the energy density of the cell 1, improving its cycle performance and safety. Furthermore, the introduced high-temperature tape 2 is a commonly used tape in the core package and does not introduce new risks, ensuring the safety of the core package.

[0049] Furthermore, during the process of obtaining the width a and the collapse depth h of the thinned area 11 of the battery cell 1, the length b of the thinned area 11 of the battery cell 1 is also obtained, wherein the length B of the high-temperature tape 2 is b-2mm.

[0050] Furthermore, the thickness H of the high-temperature tape 2 is 1.2h. When the multilayer battery cells 1 are stacked sequentially, the upper layer battery cell 1 will exert a certain pressure on the lower layer battery cell 1. In some application scenarios, making the thickness H of the high-temperature tape 2 1.2h helps to ensure that the surface of the uppermost battery cell 1 remains horizontal after the multilayer battery cells 1 are stacked sequentially.

[0051] Furthermore, the thickness H of the high-temperature tape 2 is 1.5h. When the multilayer battery cells 1 are stacked one on top of the other, the upper layer battery cell 1 will exert a certain pressure on the lower layer battery cell 1. In some other application scenarios, the thickness H of the high-temperature tape 2 is 1.5h, which helps to ensure that the surface of the uppermost battery cell 1 remains horizontal after the multilayer battery cells 1 are stacked one on top of the other.

[0052] Specifically, in this embodiment, the high-temperature tape 2 is made of polyimide. The width of the high-temperature tape 2 should nearly coincide with the edge of the positive electrode sheet, and it should be centered in the length direction.

[0053] Furthermore, the thickness H of the high-temperature tape 2 is 5um-12um. For example, the thickness H of the high-temperature tape 2 can be, but is not limited to, 5um, 6um, 7um, 8um, 9um, 10um, 11um, or 12um.

[0054] Furthermore, the thickness H of the high-temperature tape 2 is 8um-10um. For example, the thickness H of the high-temperature tape 2 is 8.1um, 8.2um, 8.3um, 8.4um, 8.5um, 8.6um, 8.7um, 8.8um, 8.9um, 9.0um, 9.1um, 9.2um, 9.3um, 9.4um, 9.5um, 9.6um, 9.7um, 9.8um, 9.9um, or 10.5um, etc.

[0055] For example, the width A of the high-temperature tape 2 is 12mm, the thickness H is 8um, and the length B is 319mm. Specifically, battery cell one consists of a positive electrode, a negative electrode, an electrolyte, and a separator. The thinned area 11 of battery cell 1 does not have high-temperature adhesive, such as... Figure 2 As shown, the negative electrode width a = 8mm and length b = 321mm, and the finished battery cell is tested for cycles according to the standard 1C fast charging process; Battery cell two: The structure and composition are exactly the same as battery cell one, the difference being that high-temperature tape is attached to the thinned areas on both sides of battery cell one. The width of high-temperature tape 2 is A = 12mm, the thickness is H = 8um, and the length is B = 319mm, as shown. Figure 3 As shown, the manufactured battery cells were cycle-tested according to the standard 1C fast charging process. The cycle performance of the two types of cells was compared, as follows: Figure 5 As shown, the cycle performance of the battery cell is significantly improved, indicating that applying high-temperature tape 2 to the thinned area 11 of the battery cell 1 can effectively improve the cycle performance of the battery cell 1.

[0056] For example, the width A of the high-temperature tape 2 is 18mm, the thickness H is 8um, and the length B is 352mm. Specifically, cell three consists of a positive electrode, a negative electrode, an electrolyte, and a separator. The thinned area of ​​cell 1 does not have high-temperature adhesive, such as... Figure 2 As shown, the width of the negative electrode thinning area is a = 15mm, and the length is b = 354mm. The finished battery cell is tested for cycles according to the standard 1C fast charging process. Battery cell four: The structure and composition are exactly the same as battery cell three, except that high-temperature adhesive is applied to the thinning areas on both sides of battery cell one. The high-temperature adhesive has a width A = 18mm, a thickness H = 8um, and a length B = 352mm. Figure 3 As shown, the prepared battery cells were tested for cycles according to the standard 1C fast charging process; the cycle performance of the two types of battery cells was compared, as follows: Figure 6 As shown, the cycle performance of cell four is significantly improved.

[0057] This embodiment also provides a lithium-ion battery, which includes a cell 1 and a high-temperature adhesive tape 2. The cell 1 has a central region 12 and thinned regions 11 located on both sides of the central region 12. The width of the thinned region is a, the length is b, and the collapse depth is h. The high-temperature adhesive tape 2 is attached to the thinned region 11, and the width of the high-temperature adhesive tape 2 is A, the length is B, and the thickness is H; wherein, B = b - 2 mm, H ≥ h; wherein, when a < 10 mm, A = 1.5a; when 10 mm ≤ a < 25 mm, A = 1.2a. This lithium-ion battery uses the above-mentioned cell thinning region compensation method to compensate for the thinned region 11 of the cell 1, reducing the electrolyte content, increasing the energy density, and improving the cycle performance and safety performance of the lithium-ion battery.

[0058] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for compensating for thinned areas in a battery cell, characterized in that, A method for compensating the collapse depth of a thinned area (11) of a lithium ion battery cell (1) relative to a middle area (12) of the cell (1) includes the following steps: Obtaining the width a and collapse depth h of the thinned area (11) of the cell (1); According to the width a and collapse depth h of the thinned area (11), determining the width A and thickness H of a high-temperature adhesive tape (2); wherein H=1.2h or 1.5h; wherein when a<10mm, A=1.5a; when 10mm≤a<25mm, A=1.2a; In the process of obtaining the width a and collapse depth h of the thinned area (11) of the cell (1), the length b of the thinned area (11) of the cell (1) is also obtained, wherein the length B of the high-temperature adhesive tape (2) is b-2mm; the high-temperature adhesive tape (2) is pasted on the thinned area (11).

2. The method of claim 1, wherein, The material of the high-temperature adhesive tape (2) is polyimide.

3. The method of claim 2, wherein, The thickness H of the high-temperature adhesive tape (2) is 5um-12um.

4. The method of claim 3, wherein, The thickness H of the high-temperature adhesive tape (2) is 8um-10um.

5. The method of claim 3, wherein, The width A of the high-temperature adhesive tape (2) is 12mm, the thickness H is 8um, and the length B is 319mm.

6. The method of claim 3, wherein, The width A of the high-temperature adhesive tape (2) is 18mm, the thickness H is 8um, and the length B is 352mm.

7. A lithium-ion battery, the thinned area (11) of the cell (1) being compensated by the method for compensating a thinned area of a cell according to any one of claims 1 to 6, characterized in that, It includes: A cell (1) is provided with a middle area (12) and a thinned area (11) on both sides of the middle area (12), the width of the thinned area is a, the length is b, and the collapse depth is h; A high-temperature adhesive tape (2) is pasted on the thinned area (11), and the width of the high-temperature adhesive tape (2) is A, the length is B, and the thickness is H; wherein B=b-2mm, H≥h; wherein when a<10mm, A=1.5a; when 10mm≤a<25mm, A=1.2a.

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