Battery cell and lithium ion battery

Abstract

The utility model discloses a battery cell and relates to the technical field of lithium ion batteries. The battery cell comprises a battery cell main body, an outer packaging film and an inner packaging film, the outer packaging film is provided with a containing cavity capable of containing the battery cell main body, and the containing cavity comprises two oppositely arranged first vertical side edges and two folded edges formed by bending the first vertical side edges; the inner packaging film is provided with a second vertical side edge which is tightly attached to the first vertical side edge, and the second vertical side edge is positioned between the outer packaging film and the battery cell main body. And when external air enters from the folded edge, the second vertical side edge of the inner packaging film blocks the external air, so that the risk that the external air enters the battery cell is reduced. The utility model also discloses a lithium ion battery.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium ion batteries, in particular to a battery core and a lithium ion battery. Background Art

[0002] Lithium-ion batteries are a commonly used rechargeable battery widely used in electric vehicles, mobile devices, energy storage systems and other fields. Lithium-ion batteries mainly include steel shell, aluminum shell, soft pack and square types. Among them, soft pack lithium-ion batteries have received extensive attention and application due to their advantages such as light weight, small size and high safety. Figure 1 As shown, in the manufacturing process of the soft-pack lithium-ion battery, the battery cell body 1 is generally wrapped with a packaging film 20, and a folded edge 22 is formed on the side of the packaging film 20 to form a closed space to prevent leakage of the electrolyte.

[0003] However, for ultra-thin soft-pack lithium-ion batteries, the folding height of the packaging film cannot exceed the thickness of the battery cell. Therefore, the width of the folding edge is designed to be small, generally between 1 and 2 mm. This weakens the seal strength at the folding edge, reduces the barrier performance, and allows external gas to easily enter the battery cell through the folding edge, causing hydrolysis or oxidation of the electrolyte, affecting the performance of the battery cell. Utility Model Content

[0004] The utility model provides a battery core, which can improve the barrier performance of the package folded edge of the battery core and reduce the risk of external gas entering the battery core.

[0005] In order to achieve the above-mentioned purpose, the utility model adopts the following technical solutions:

[0006] A battery cell, comprising:

[0007] Battery cell body;

[0008] An outer packaging film, wherein the outer packaging film is provided with a receiving cavity capable of receiving the battery cell body, the receiving cavity comprising two oppositely arranged first vertical side edges and two folded edges formed by bending the first vertical side edges;

[0009] The inner packaging film has a second vertical side edge closely disposed with the first vertical side edge, and the second vertical side edge is located between the outer packaging film and the battery cell body.

[0010] In some embodiments, the height of the second vertical side is higher than the height of the folded edge.

[0011] In some embodiments, the battery cell body includes two oppositely disposed main planes and two opposite side surfaces, the inner packaging film also includes a bottom surface, the second vertical side edges are located on both sides of the bottom surface, and the bottom surface is used to fit with at least one main plane.

[0012] In some embodiments, two inner packaging films are provided, and each inner packaging film is adhered to a side surface and a part of the main plane of the battery cell body.

[0013] In some embodiments, the inner packaging film covers at least one main plane and two side surfaces of the battery cell body.

[0014] In some embodiments, an outer surface of the inner packaging film is coated with adhesive, and the adhesive is used to bond the inner packaging film to the outer packaging film.

[0015] In some embodiments, the outer packaging film and the inner packaging film are aluminum-plastic films.

[0016] In some embodiments, the outer packaging film is formed by folding an aluminum-plastic film in half, one side of the aluminum-plastic film is provided with a pit, and the other side seals the pit to form the accommodating cavity.

[0017] In some embodiments, the height of the folded edge is smaller than the height of the battery cell body.

[0018] The embodiment of the utility model further provides a lithium ion battery, which includes the battery cell as described in the above embodiment.

[0019] In the technical solution of the utility model, the second vertical side edge of the inner packaging film is close to the first vertical side edge of the outer packaging film and is located between the outer packaging film and the battery body. When outside air enters from the folded edge, the second side edge of the inner packaging film blocks the outside air and increases the path for air to enter the battery, thereby reducing the risk of outside air entering the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the internal structure of a battery cell in the prior art;

[0021] Figure 2 This is a schematic diagram of the internal structure of a battery cell in one embodiment of the utility model;

[0022] Figure 3 This is a schematic diagram of the internal structure of a battery cell in another embodiment of the utility model;

[0023] Figure 4 Schematic diagram of the internal structure of a battery cell in another embodiment of the present invention.

[0024] Description of Figure Numbers

[0025] Label name Label name 1 Battery body 2 Outer packaging film 21 Accommodation cavity 211 First vertical side 22 Hem 3 Inner packaging film 31 Second vertical side 4 Adhesive

[0026] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0027] In the present invention, the terms "disposed", "provided with", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The orientation or position relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or position relationship shown in the drawings and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0030] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in this utility model can be understood according to specific circumstances.

[0031] In order to make the purpose, technical solution and advantages of 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.

[0032] The present utility model provides a battery cell which is applied in the field of ultra-thin lithium-ion batteries. Figure 2 As shown, Figure 2Schematic diagram of the internal structure of the battery cell in this embodiment. The battery cell in this embodiment includes a battery cell body 1, an outer packaging film 2 and an inner packaging film 3. The outer packaging film 2 is provided with a receiving cavity 21 for receiving the battery cell body 1, and the receiving cavity 21 includes two oppositely arranged first vertical sides 211 and two folded edges 22 formed by bending the first vertical sides 211; the inner packaging film 3 has a second vertical side 31 closely arranged with the first vertical side 211, and the second vertical side 31 is located between the outer packaging film 2 and the battery cell body 1.

[0033] In this embodiment, the battery cell body 1 can be formed by winding or lamination. Exemplarily, the battery cell body 1 includes a positive electrode sheet, a separator and a negative electrode sheet. The positive electrode sheet, the separator and the negative electrode sheet are stacked in sequence and then wound to form a wound battery cell body 1. Alternatively, the battery cell body 1 includes a plurality of positive electrode sheets, separators and negative electrode sheets, and a plurality of positive electrode sheets, separators and negative electrode sheets are stacked in sequence to form a laminated battery cell body 1. The outer packaging film 2 of the present embodiment may be an upper packaging film and a lower packaging film connected to each other, wherein a receiving cavity 21 for receiving the battery cell body 1 is formed between the upper packaging film and the lower packaging film, and the receiving cavity 21 includes two oppositely arranged first vertical side edges 211, and two folded edges 22 formed by bending the two first vertical side edges 211, and the two folded edges 22 are formed by connecting the edges of the upper and lower packaging films. Exemplarily, the two folded edges 22 are formed by hot pressing and fusing the edges of the two packaging films, thereby closing the receiving cavity 21 to enclose the battery cell body 1 in the receiving cavity 21.

[0034] like Figure 1 As shown, since the thickness of the battery cell main body 1 is relatively thin, in order to ensure that the thickness of the battery cell main body 1 meets the size requirements, the folded edge 22 cannot exceed the height of the battery cell main body 1 after being bent. In this way, the width of the folded edge 22 is designed to be smaller, thereby weakening the sealing strength of the folded edge 22, causing the battery cell's performance in blocking external air to decline, and external gas can easily enter the battery cell directly from the folded edge 22, affecting the performance of the battery cell.

[0035] To this end, the battery cell of the present embodiment further includes an inner packaging film 3. Specifically, the inner packaging film 3 is disposed between the battery cell body 1 and the outer packaging film 2, and the inner packaging film 3 has a second vertical side 31 that is closely disposed with the first vertical side 211. In this way, the second vertical side 31 of the inner packaging film 3 shields the bend of the folded edge 22 inside the battery cell. When outside air enters the accommodating cavity 21 from the folded edge 22, the second vertical side 31 blocks the outside air, preventing the outside air from directly contacting the battery cell body 1, and increases the path for the air to enter the battery cell, thereby improving the sealing of the battery cell and reducing the risk of outside air entering the battery cell.

[0036] In some embodiments, please refer to Figure 2 , the height of the second vertical side 31 is higher than the height of the folded edge 22 .

[0037] In this embodiment, outside air enters from the folded edge 22 and flows along the direction of the second vertical side 31. Since the height of the second vertical side 31 is higher than the height of the folded edge 22, the path for outside air to enter the interior of the battery cell is further increased, thereby improving the sealing of the battery cell.

[0038] In some embodiments, the battery cell body 1 includes two opposite main planes and two opposite side surfaces, the inner packaging film 3 also includes a bottom surface, the second vertical side edges 31 are located on both sides of the bottom surface, and the bottom surface is used to fit with at least one main plane.

[0039] In this embodiment, Figure 2 As shown, the battery cell body 1 is flat as a whole, the two main planes of the circumference of the battery cell body 1 are located on the upper and lower sides of the battery cell body 1, the two side surfaces of the battery cell body 1 are located on the left and right sides of the battery cell body 1, and the two folded edges 22 of the outer packaging film 2 are respectively arranged on the outside of the two side surfaces of the battery cell body 1.

[0040] The bottom surface of the inner packaging film 3 is attached to at least one main plane of the battery cell body 1. Exemplarily, the bottom surface of the inner packaging film 3 is attached to a main plane of the battery cell body 1 close to the folded edge, and the two second vertical side edges 31 of the inner packaging film 3 are attached to the two side surfaces of the battery cell body 1. The inner packaging film 3 is half-wrapped to cover the battery cell body 1, and the outer surface of the inner packaging film 3 is arranged toward the folded edge 22. When outside air enters the accommodating cavity 21 from the folded edge 22, the outside air is blocked by the inner packaging film 3 attached to the circumference of the battery cell body 1 and does not directly contact the battery cell body 1. The outside air can only invade the battery cell body 1 along the extension direction of the inner packaging film 3. In this way, the path for outside air to invade the battery cell body 1 is increased, thereby reducing the risk of outside air contacting the battery cell body 1 and improving the sealing of the battery cell.

[0041] In another embodiment, Figure 3 As shown, two inner packaging films 3 are provided, and each inner packaging film 3 is attached to a side surface and a part of the main plane of the battery body 1 .

[0042] In this embodiment, the two inner packaging films 3 are attached to the surface of the battery body 1 at the positions corresponding to the two folded edges 22, specifically, each packaging film is attached to a side surface and part of the main plane of the battery body 1. When the outside air enters the accommodating cavity 21 from the folded edges 22 on both sides, the outside air is blocked by the two inner packaging films 3 attached to the circumference of the battery body 1 and will not directly contact the battery body 1. The outside air can only invade the battery body 1 along the extension direction of the inner packaging film 3. In this way, the path for the outside air to invade the battery body 1 is increased, thereby reducing the risk of the outside air contacting the battery body 1 and improving the sealing of the battery.

[0043] In another embodiment, the inner packaging film 3 covers at least one main plane and two side surfaces of the battery cell body 1 .

[0044] For example, Figure 3 As shown, the inner packaging film 3 covers a main plane and two side surfaces of the battery body 1 close to the folded edge 22, and the inner packaging film 3 covers the battery body 1 in a half-wrapped shape. Figure 4 As shown, the inner packaging film 3 is coated on the circumference of the battery cell body 1, and completely covers the outer circumference of the battery cell body 1. When the outside air enters the accommodating cavity 21 from the folded edge 22, the outside air is blocked by the inner packaging film 3 attached to the outer circumference of the battery cell body 1 and does not directly contact the battery cell body 1. In this way, the risk of the outside air contacting the battery cell body 1 is reduced, and the sealing of the battery cell is improved.

[0045] In some embodiments, the outer surface of the inner packaging film 3 is coated with adhesive 4 , and the adhesive 4 is used to bond the inner packaging film 3 to the outer packaging film 2 .

[0046] In this embodiment, the adhesive 4 can be glue. The adhesive 4 is applied to the outer surface of the inner packaging film 3 to bond the inner packaging film 3 to the outer packaging film 2. Exemplarily, after the battery body 1 is placed in the accommodating cavity 21 of the outer packaging film 2, the inner packaging film 3 is attached to the outer peripheral surface of the battery body 1, and the adhesive 4 is applied to the outer surface of the inner packaging film 3 to bond the inner packaging film 3 to the outer packaging film 2, thereby improving the sealing of the battery.

[0047] In some embodiments, the outer packaging film 2 and the inner packaging film 3 are aluminum-plastic films, which include a polypropylene layer, an aluminum foil layer and a nylon layer from the inside to the outside.

[0048] In some embodiments, the outer packaging film 2 is formed by folding an aluminum-plastic film in half, one side of the aluminum-plastic film is provided with a pit, and the other side closes the pit to form the accommodating cavity 21 .

[0049] In this embodiment, the pit is formed by a punching molding process, and the outer packaging film 2 is deformed by a punching mold, thereby forming a pit on the outer packaging film 2. One side of the outer packaging film 2 is punched to form a pit that can accommodate the battery body 1. After the battery body 1 is placed in the pit, the inner packaging film 3 is attached to the outer peripheral surface of the battery body 1, and the adhesive 4 is applied to the outer surface of the inner packaging film 3. Finally, the other side of the outer packaging film 2 is folded to close the pit, thereby covering the battery body 1.

[0050] In some embodiments, the height of the folded edge 22 is less than the height of the battery body 1, so that after the folded edge 22 is bent toward the battery body 1, the folded edge 22 will not exceed the battery body 1 and cause the battery cell to become thicker, thereby meeting the requirement of miniaturization of the ultra-thin battery cell.

[0051] The embodiment of the utility model further provides a lithium ion battery, which includes the battery cell described in the above embodiment.

[0052] The specific structure of the battery cell refers to the above embodiments. Since the lithium-ion battery adopts all the technical solutions of all the above embodiments, it at least has all the technical effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0053] The above is only a specific implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A battery cell, characterized in that: include: Battery cell body; An outer packaging film, wherein the outer packaging film is provided with a receiving cavity capable of receiving the battery cell body, the receiving cavity comprising two oppositely arranged first vertical side edges and two folded edges formed by bending the first vertical side edges; The inner packaging film has a second vertical side edge closely disposed with the first vertical side edge, and the second vertical side edge is located between the outer packaging film and the battery cell body.

2. The battery cell according to claim 1, characterized in that: The height of the second vertical side edge is higher than the height of the folded edge.

3. The battery cell according to claim 1, characterized in that: The battery cell body includes two oppositely arranged main planes and two opposite side surfaces, the inner packaging film also includes a bottom surface, the second vertical side edges are located on both sides of the bottom surface, and the bottom surface is used to fit with at least one main plane.

4. The battery cell according to claim 3, characterized in that: The inner packaging films are provided in two pieces, and each inner packaging film is attached to a side surface and a part of the main plane of the battery body.

5. The battery cell according to claim 3, characterized in that: The inner packaging film covers at least one main plane and two side surfaces of the battery core body.

6. The battery cell according to any one of claims 1 to 5, characterized in that: The outer surface of the inner packaging film is coated with adhesive, and the adhesive is used to bond the inner packaging film and the outer packaging film.

7. The battery cell according to claim 1, characterized in that: The outer packaging film and the inner packaging film are aluminum-plastic films.

8. The battery cell according to claim 7, characterized in that: The outer packaging film is formed by folding an aluminum-plastic film in half, one side of the aluminum-plastic film is provided with a pit, and the other side seals the pit to form the accommodating cavity.

9. The battery cell according to claim 1, characterized in that: The height of the folded edge is smaller than the height of the battery core body.

10. A lithium ion battery, characterized in that: Comprising the battery cell as claimed in any one of claims 1 to 9.

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