Battery cell mylar membrane

Abstract

The utility model provides a battery cell Mylar membrane. The battery cell Mylar membrane comprises a first Mylar membrane large surface and a second Mylar membrane large surface, a first mylar film side surface, a second mylar film side surface, a third mylar film side surface and a fourth mylar film side surface; the bottom support surface is of a porous structure; the ends, close to the bottom supporting face, of the first mylar film side faces are each provided with a first opening structure, the ends, close to the bottom supporting face, of the second mylar film side faces are each provided with a second opening structure, and the ends, close to the bottom supporting face, of the third mylar film side faces are each provided with a third opening structure. And a fourth opening structure is arranged at one end, close to the bottom support surface, of each fourth mylar film side surface. According to the battery cell mylar membrane disclosed by the utility model, electrolyte can be simultaneously permeated and absorbed into a diaphragm and a pole piece of a battery cell through the opening grooves in the side surfaces and the bottom holes, and the opening grooves in the two side edges are convenient for promoting the battery cell to absorb, permeate and internally flow the electrolyte, so that the infiltration effect of the battery cell is improved, and the liquid injection time is shortened.

Description

Technical Field

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

[0002] In the production process of battery cells, injecting electrolyte into the battery cells is a key step. However, the Mylar membrane used in existing battery cells often has problems such as slow injection speed, uneven injection, and easy generation of bubbles during the injection process. The electrolyte is concentrated at the bottom during the injection and static process, and absorption and infiltration can only be carried out from the bottom, affecting the production efficiency and quality of the battery. The Chinese utility model patent with publication number CN 219419126U discloses a battery cell protective film, battery and battery device for lithium batteries. The patent provides a Mylar membrane, which has no porous structure at the bottom and no open grooves on the side. Although its coating method can make it not easy to deform or tear when subjected to force, this structural mode has the problems of slow injection speed and uneven injection. Therefore, it is very necessary to provide a Mylar membrane for battery cells that has a fast injection speed and uniform injection. Utility Model Content

[0003] In view of the problems existing in the background technology, the purpose of the present invention is to provide a mylar film for a battery cell, which can allow the electrolyte to penetrate and absorb into the diaphragm and electrode of the battery cell through the side opening grooves and the bottom holes at the same time. The opening grooves on both sides facilitate the battery cell to absorb, penetrate and flow the electrolyte internally, thereby improving the battery cell infiltration effect and shortening the injection time.

[0004] In order to achieve the above-mentioned objectives, the present invention provides a Mylar film for a battery cell, comprising: a first mylar film large surface, a second mylar film large surface; a first mylar film side surface, a second mylar film side surface, a third mylar film side surface, and a fourth mylar film side surface; a bottom support surface, wherein the bottom support surface is a porous structure; the first mylar film side surface is provided with a first opening structure at one end close to the bottom support surface, the second mylar film side surface is provided with a second opening structure at one end close to the bottom support surface, the third mylar film side surface is provided with a third opening structure at one end close to the bottom support surface, and the fourth mylar film side surface is provided with a fourth opening structure at one end close to the bottom support surface.

[0005] As a preferred solution of the present invention, the first mylar film large surface and the second mylar film large surface are connected to the bottom support surface.

[0006] As a preferred solution of the present invention, the first mylar film side surface and the third mylar film side surface are both connected to the second mylar film large surface, and the second mylar film side surface and the fourth mylar film side surface are both connected to the first mylar film large surface.

[0007] As a preferred embodiment of the present invention, the battery cell Mylar film includes a first crease line, a second crease line, a third crease line, a fourth crease line, a fifth crease line, and a sixth crease line.

[0008] As a preferred solution of the present invention, the first opening structure is symmetrical to the second opening structure; and the third opening structure is symmetrical to the fourth opening structure.

[0009] As a preferred embodiment of the present invention, after the battery cell mylar film is folded and merged along the folding line, the first mylar film side surface and the second mylar film side surface overlap and merge to form the first battery cell mylar film side surface, and the third mylar film side surface and the fourth mylar film side surface overlap and merge to form the second battery cell mylar film side surface.

[0010] As a preferred solution of the present invention, the first opening structure and the second opening structure overlap and merge to form a first opening slot; the third opening structure and the fourth opening structure overlap and merge to form a second opening slot.

[0011] As a preferred embodiment of the present invention, the first and second openings are both U-shaped, with side widths of 10-20 mm and heights of 60-65 mm. The openings on both sides facilitate electrolyte absorption, penetration, and internal flow within the battery cell, improving the cell's wetting effect and shortening the injection time.

[0012] As a preferred embodiment of the present invention, the first mylar film large surface and the second mylar film large surface respectively wrap the two large surfaces of the bare battery cell, the first battery cell mylar film side surface and the second battery cell mylar film side surface respectively wrap the two side surfaces of the bare battery cell, and the bottom support surface correspondingly wraps the bottom of the bare battery cell.

[0013] A lithium battery comprises the above-mentioned battery cell Mylar film.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0015] The electrolyte is absorbed into the cell's diaphragm and electrode simultaneously through the openings on the side and bottom of the Mylar membrane. The openings on both sides facilitate electrolyte absorption, penetration, and internal flow, improving cell wetting and shortening injection time. This improves electrolyte fluidity within the cell, reduces internal electrolyte bubbles, and enhances electrolyte uniformity. It also assists in heat dissipation and cooling during cell operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a schematic diagram of the Mylar film of the battery cell in the present invention.

[0018] Figure 2 This is a three-dimensional diagram of the Mylar film of the battery cell in this utility model.

[0019] Description of reference numerals:

[0020] 11-large surface of the first mylar film, 12-large surface of the second mylar film, 21-side surface of the first mylar film, 22-side surface of the second mylar film, 23-side surface of the third mylar film, 24-side surface of the fourth mylar film, 31-first opening structure, 32-second opening structure, 33-third opening structure, 34-fourth opening structure, 4-bottom support surface, 51-first crease line, 52-second crease line, 53-third crease line, 54-fourth crease line, 55-fifth crease line, 56-sixth crease line, 2a-side surface of the first battery cell mylar film, 22-side surface of the second battery cell mylar film, 3a-first opening groove, 3b-second opening groove. DETAILED DESCRIPTION

[0021] The following is a further detailed description of the embodiments of the present invention in conjunction with the accompanying drawings and examples. The detailed descriptions and drawings of the following examples are used to illustrate the principles of the present invention, but cannot be used to limit the scope of the present invention. The present invention can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims. The present invention provides these embodiments to make the present invention thorough and complete, and to fully express the scope of the present invention to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values ​​described in these embodiments should be interpreted as merely exemplary and not as limitations.

[0022] It should be noted that, in the description of this utility model, unless otherwise specified, "plurality" means greater than or equal to two; terms such as "upper," "lower," "left," "right," "inner," and "outer" indicating directions or positional relationships are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on this utility model. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] In addition, the terms "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different parts. "Vertical" does not mean perpendicular in the strict sense, but is within the allowable error range. "Parallel" does not mean parallel in the strict sense, but is within the allowable error range. "Include" or "comprising" and similar terms mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of also including other elements. It should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" 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 direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. All terms used in the present invention have the same meaning as understood by those of ordinary skill in the art in the field to which the present invention belongs, unless otherwise specifically defined. It should also be understood that terms defined in, for example, commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or highly formal sense unless expressly so defined herein.

[0024] The battery cell mylar film of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] First, the mylar film of the battery cell of the present invention is described.

[0026] Reference Figure 1 According to the utility model, the Mylar film of the battery cell includes: a first mylar film large surface 11, a second mylar film large surface 12; a first mylar film side surface 21, a second mylar film side surface 22, a third mylar film side surface 23, and a fourth mylar film side surface 24; a bottom support surface 4, and the bottom support surface 4 is a porous structure; the first mylar film side surface 21 is provided with an opening structure 31 at one end close to the bottom support surface 4, the second mylar film side surface 22 is provided with an opening structure 32 at one end close to the bottom support surface 4, the third mylar film side surface 23 is provided with an opening structure 33 at one end close to the bottom support surface 4, and the fourth mylar film side surface 24 is provided with an opening structure 34 at one end close to the bottom support surface 4.

[0027] As a preferred embodiment of the present invention, the first large mylar film surface 11 and the second large mylar film surface 12 are connected to the bottom support surface 4. The first large mylar film surface 11 and the second large mylar film surface 12 are connected to the bottom support surface 4 in an integrated manner. The first large mylar film surface 11 and the second large mylar film surface 12 are on both sides of the bottom support surface 4. A second fold line 52 is defined between the first large mylar film surface 11 and the bottom support surface 4, and a first fold line 51 is defined between the second large mylar film surface 12 and the bottom support surface 4. This integrated connection method is beneficial to the stability of the Mylar film of the entire battery cell. The connection between the large mylar film surfaces 11 and 12 and the bottom support surface 4 provides additional support, enhances the structural stability of the battery cell, and helps maintain its shape and function when the battery is subjected to impact or vibration. The insulating properties of the Mylar film help prevent short circuits within the battery cell. By connecting the large mylar film surfaces 11 and 12 to the bottom support surface 4, proper isolation between the electrodes within the battery cell can be ensured.

[0028] As a preferred embodiment of the present invention, the first mylar film side surface 21 and the third mylar film side surface 23 are both connected to the second mylar film large surface 12, and the second mylar film side surface 22 and the fourth mylar film side surface 24 are both connected to the first mylar film large surface 11. The first mylar film side surface 21 and the third mylar film side surface 23 are on both sides of the second mylar film large surface 12, and the first mylar film side surface 21, the third mylar film side surface 23, and the second mylar film large surface 12 are also connected in an integrated manner. This integrated connection method is beneficial to the stability of the entire battery cell Mylar film. After folding through the third crease line 53 and the fifth crease line 55, the connection is connected and fixed with a termination tape to prevent the entire film from deforming or falling off. The above layout helps to distribute heat inside the battery and can promote heat transfer from the active area of ​​the battery cell to the edge, thereby improving the overall thermal management efficiency.

[0029] As a preferred embodiment of the present invention, the Mylar film of the battery cell includes a first crease line, a second crease line, a third crease line, a fourth crease line, a fifth crease line, and a sixth crease line.

[0030] As a preferred embodiment of the present invention, the first opening structure 31 and the second opening structure 32 are symmetrical, and the third opening structure 33 and the fourth opening structure 34 are symmetrical. The first opening structure 31 and the second opening structure 32 are of the same size and their openings are opposite to each other, which facilitates the formation of opening grooves in the Mylar film of the battery cell.

[0031] Reference Figure 2As a preferred embodiment of the present invention, after the cell's Mylar film is folded and combined along a fold line, the first Mylar film side 21 overlaps and merges with the second Mylar film side 22 to form the first cell's Mylar film side 2a. The third Mylar film side 23 overlaps and merges with the fourth Mylar film side 24 to form the second cell's Mylar film side 2b. The first and second Mylar film sides 21 and 22 are joined and secured with a termination tape to prevent deformation or detachment. The third and fourth Mylar film sides 23 and 24 are joined and secured at their edges with a termination tape to prevent deformation or detachment. The durability and impact resistance of a cell are important performance indicators. By folding and combining the various parts of the cell along specific fold lines, the thickness of the cell's side surfaces can be effectively increased without adding additional material. This ingenious design modification allows the cell to better disperse and absorb impact forces when subjected to physical impact, thereby reducing damage to its internal structure. The increased side thickness not only improves the cell's structural stability but also enhances its mechanical strength. This means the battery cell can withstand greater pressure and twisting forces without easily deforming or damaging. This is crucial for the safety of the battery during transportation and use, especially in devices that need to be frequently moved or operate in harsh environments. In addition, this design also helps improve the thermal stability of the battery cell. During the battery charging and discharging process, heat is generated inside the battery cell. If the heat cannot be dissipated in time, it may cause the battery cell to overheat, affecting the battery's performance and lifespan. By increasing the side thickness, the thermal conductivity efficiency of the battery cell can be improved, which helps to evenly distribute and quickly dissipate heat, thereby protecting the battery cell from thermal damage.

[0032] One long side of the first mylar film side surface 21 is integrally connected to the second mylar film large surface 12, and one long side of the second mylar film side surface 22 is integrally connected to the first mylar film large surface 11. After folding along the first folding line 51, the second folding line 52, the third folding line 53, and the fourth folding line 54, the first mylar film side surface 21 and the second mylar film side surface 22 are folded and overlapped. The mylar film side surface 2a of the first battery cell formed in this way is thickened. The thickened Mylar film can provide better chemical stability, reduce adverse reactions with the electrolyte, improve the reliability of the battery, and improve the overall performance of the battery, including energy density, power density, and cycle life. One long side of the third mylar film side surface 23 is integrally connected to the second mylar film large surface 12, and one long side of the fourth mylar film side surface 24 is integrally connected to the first mylar film large surface 11. After folding along the first folding line 51, the second folding line 52, the fifth folding line 55, and the sixth folding line 56, the third mylar film side surface 23 and the fourth mylar film side surface 24 are folded and overlapped, so that the mylar film side surface 2b of the first battery cell formed in this way is also thickened.

[0033] As a preferred embodiment of the present invention, opening structures 31 and 32 overlap to form a first opening slot 3a; opening structures 33 and 34 overlap to form a second opening slot 3b. The overlapping edges of opening structures 31 and 32, and the overlapping edges of opening structures 33 and 34, are connected and secured with end tape to prevent deformation or falling off.

[0034] As a preferred embodiment of the present invention, the first open groove 3a and the second open groove 3b are both close to U-shaped, with a side width of 10-20 mm and a height of 60-65 mm. Full contact between the battery cell and the electrolyte is one of the key factors to ensure battery performance. The design of the open grooves on both sides provides a direct infiltration channel for the electrolyte, which not only promotes the uniform distribution of the electrolyte inside the battery cell, but also significantly improves the infiltration effect of the battery cell. This design allows the electrolyte to penetrate into every corner of the battery cell more quickly, thereby shortening the injection time and improving production efficiency. At the same time, a good infiltration effect also helps to improve the charge and discharge performance and cycle life of the battery, ensuring that the battery can still maintain a high energy output after long-term use.

[0035] As a preferred embodiment of the present invention, the first mylar film large surface 11 and the second mylar film large surface 12 respectively wrap the two large surfaces of the bare battery cell, the first battery cell mylar film side surface 2a and the second battery cell mylar film side surface 2b respectively wrap the two side surfaces of the bare battery cell, and the bottom support surface 4 correspondingly wraps the bottom of the bare battery cell.

[0036] A lithium battery comprises the above-mentioned battery cell Mylar film.

[0037] In summary, the Mylar film of the battery cell of the present invention not only has strong stability, but also because of the structural mode of setting open grooves on both sides of the Mylar film body, the electrolyte can penetrate and absorb into the diaphragm and electrode of the battery cell through the openings on the side and bottom of the Mylar film at the same time. The open grooves on both sides facilitate the absorption, penetration and internal flow of the electrolyte by the battery cell, thereby improving the wetting effect of the battery cell and shortening the injection time.

[0038] Example 1

[0039] The battery cell mylar film of the utility model is used to perform liquid injection on a 280Ah battery cell, and the liquid injection time of the battery cell with the mylar film is tested.

[0040] Comparative Example 1

[0041] Use conventional mylar film to fill 280Ah battery cells and test the filling time of the mylar film battery cells.

[0042] Results: Compared with conventional mylar films, the average injection time of the mylar film battery cell using the utility model can be shortened by about 6%.

[0043] In other embodiments, the battery cells wrapped by the folded mylar film can be 2 bare battery cells in parallel or 4 bare battery cells in parallel, and there is no limit on the number of bare battery cells in parallel when achieving the effect of wrapping the battery cells.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A Mylar film for a battery cell, characterized in that: include: A first mylar film large surface (11), a second mylar film large surface (12); a first mylar film side surface (21), a second mylar film side surface (22), a third mylar film side surface (23), and a fourth mylar film side surface (24); A bottom supporting surface (4), wherein the bottom supporting surface (4) is a porous structure; The first mylar film side surface (21) is provided with a first opening structure (31) at one end close to the bottom support surface (4), the second mylar film side surface (22) is provided with a second opening structure (32) at one end close to the bottom support surface (4), the third mylar film side surface (23) is provided with a third opening structure (33) at one end close to the bottom support surface (4), and the fourth mylar film side surface (24) is provided with a fourth opening structure (34) at one end close to the bottom support surface (4).

2. The Mylar film for the battery cell according to claim 1, characterized in that: The first mylar film large surface (11) and the second mylar film large surface (12) are connected to the bottom support surface (4).

3. The Mylar film for the battery cell according to claim 1, characterized in that: The first mylar film side surface (21) and the third mylar film side surface (23) are both connected to the second mylar film large surface (12). The second mylar film side surface (22) and the fourth mylar film side surface (24) are both connected to the first mylar film large surface (11).

4. The Mylar film for the battery cell according to claim 1, characterized in that: The battery cell Mylar film comprises a first crease line (51), a second crease line (52), a third crease line (53), a fourth crease line (54), a fifth crease line (55), and a sixth crease line (56).

5. The Mylar film for the battery cell according to claim 1, characterized in that: The first opening structure (31) and the second opening structure (32) are symmetrical; the third opening structure (33) and the fourth opening structure (34) are symmetrical.

6. The Mylar film for the battery cell according to claim 1, characterized in that: After the cell mylar film is folded and merged along the folding line, the first mylar film side surface (21) and the second mylar film side surface (22) overlap and merge to form a first cell mylar film side surface (2a), and the third mylar film side surface (23) and the fourth mylar film side surface (24) overlap and merge to form a second cell mylar film side surface (2b).

7. The Mylar film for the battery cell according to claim 6, characterized in that: The first opening structure (31) and the second opening structure (32) overlap and merge to form a first opening slot (3a); the third opening structure (33) and the fourth opening structure (34) overlap and merge to form a second opening slot (3b).

8. The Mylar film for the battery cell according to claim 7, characterized in that: The first opening groove (3a) and the second opening groove (3b) are both close to U-shaped, with a side width of 10-20 mm and a height of 60-65 mm.

9. The Mylar film for the battery cell according to claim 2 or 6, characterized in that: The first mylar film large surface (11) and the second mylar film large surface (12) respectively wrap the two large surfaces of the bare battery core, the first battery core mylar film side surface (2a) and the second battery core mylar film side surface (2b) respectively wrap the two side surfaces of the bare battery core, and the bottom support surface (4) correspondingly wraps the bottom of the bare battery core.

10. A lithium battery, characterized in that: The invention comprises the Mylar film of the battery cell according to any one of claims 1 to 9.

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