Power type soft package battery cell structure

Abstract

The utility model provides a kind of power type soft package battery cell structure, it is related to power battery technical field, the soft package battery cell structure includes: battery cell component, battery cell component includes positive plate, negative plate and diaphragm, positive plate and negative plate are stacked and set, diaphragm is set between positive plate and negative plate, positive plate and negative plate are connected with positive lug and negative lug respectively, positive lug and negative lug are set in the both ends of battery cell component;Aluminum plastic film, battery cell component is encapsulated in aluminum plastic film and forms battery cell body, aluminum plastic film is equipped with top seal seal area in the position of positive lug and negative lug, top seal seal area is concave, the notch of concave top seal seal area is towards the inside of aluminum plastic film, the both sides of aluminum plastic film are equipped with side seal seal area;The soft package battery cell structure optimizes top seal seal area structure, uses concave top seal seal area as top seal head to carry out top seal, avoids the problem of L-shaped seal area corner wrinkle of convex top seal head, improves top seal seal thickness consistency and encapsulation sealing property.

Description

Technical Field

[0001] This utility model belongs to the field of power battery technology, and more specifically, relates to a power-type soft-pack battery cell structure. Background Technology

[0002] Power batteries are mainly classified into three types according to their packaging form: pouch, prismatic, and cylindrical. Pouch cells are constructed by stacking negative electrode sheets, separators, and positive electrode sheets sequentially to form a cell assembly 1, then welding positive and negative tabs (aluminum positive tabs and nickel-plated copper negative tabs), and finally using an aluminum-plastic film 7 as the packaging material. Pouch batteries outperform prismatic and cylindrical cells in terms of cell energy density, rate performance, heat dissipation, safety, and cycle life.

[0003] Currently, such as Figure 4 As shown, the pouch cell is encapsulated using an aluminum-plastic film. The sealing edge where the positive and negative terminals are located requires a relatively wide top sealing area, which reduces the volumetric energy density of the pouch cell. This negative impact becomes even more pronounced when the width of the pouch cell needs to be increased to reduce its aspect ratio. The utility model patent with application number 202121745220.9 aims to mitigate the negative impact of the top sealing area on the volumetric energy density of the pouch cell, such as... Figure 5 As shown, the top sealing area adopts a convex top sealing head and an L-shaped sealing area structure on both sides of the convex top sealing head. After top sealing, the excess part of the top sealing area is cut off. However, when using a convex top sealing head, a large area of ​​unsealed area 14 is left on the outside of the top sealing seal. The aluminum-plastic film is deformed by heat extrusion, which easily causes wrinkles in the seal at the corner of the L-shaped sealing area, making it difficult to ensure the consistency of the seal thickness and affecting the sealing performance. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a power-type soft-pack battery cell structure. This solves the problem mentioned in the background art: currently, in order to improve the negative impact of the top sealing area on the volumetric energy density of the soft-pack battery cell, the top sealing area adopts a convex top sealing head and an L-shaped sealing area structure on both sides of the convex top sealing head. However, when the aluminum-plastic film is heated and deformed, wrinkles easily occur at the corners of the L-shaped sealing area, making it difficult to ensure the consistency of the sealing thickness and affecting the sealing performance.

[0005] To achieve the above objectives, this utility model provides a power-type pouch cell structure, which includes:

[0006] A battery cell assembly, comprising a positive electrode, a negative electrode, and a separator, wherein the positive electrode and the negative electrode are stacked, the separator is disposed between the positive electrode and the negative electrode, the positive electrode and the negative electrode are respectively connected to a positive tab and a negative tab, and the positive tab and the negative tab are disposed at both ends of the battery cell assembly;

[0007] The aluminum-plastic film is used to encapsulate the battery cell assembly to form the battery cell body. The aluminum-plastic film has a top sealing area at the positions of the positive and negative tabs. The top sealing area is concave, with the opening of the concave top sealing area facing the interior of the aluminum-plastic film. The top sealing area includes a flat sealing area and oblique sealing areas located on both sides of the opening. The aluminum-plastic film has side sealing areas on both sides.

[0008] Preferably, the sealing positions at the four corners of the battery cell body are cut with oblique lines to form cut edges.

[0009] Preferably, the angle between the horizontal side of the flat sealing area and the oblique side of the oblique sealing area is between 135° and 170°.

[0010] Preferably, the cut edge is parallel to the oblique edge of the oblique sealing area, and the width of the oblique sealing area is less than or equal to the width of the flat sealing area.

[0011] Preferably, the width of the flat sealing area is 5-8mm, the width of the oblique sealing area is 2-8mm, the length of the oblique side projection of the oblique sealing area in the side direction of the battery cell body is 5-10mm, and the length of the oblique side projection of the oblique sealing area in the end direction of the battery cell body is 10-50mm.

[0012] Preferably, the ratio of the length of the battery cell body to the width of the battery cell body is less than or equal to 1.25.

[0013] Preferably, the width of the positive electrode tab is greater than or equal to the width of the negative electrode tab, and the ratio of the width of the negative electrode tab to the width of the battery cell body is greater than or equal to 0.5.

[0014] Preferably, the ratio of the length to the width of the positive electrode is less than or equal to 1.1, the length of the negative electrode is 1-4 mm longer than the length of the positive electrode, and the width of the negative electrode is 1-4 mm wider than the width of the positive electrode.

[0015] Preferably, the ratio of the product of the length and width of the battery cell body to the thickness of the battery cell body is greater than or equal to 4300 mm, and the ratio of the product of the length and width of the battery cell body to the energy of the battery cell body is greater than or equal to 200 mm. 2 / Wh.

[0016] Preferably, the width of the battery cell body is greater than or equal to 185 mm and less than or equal to 210 mm, the length of the battery cell body is greater than or equal to 200 mm and less than or equal to 260 mm, the thickness of the battery cell body is greater than or equal to 5 mm and less than or equal to 10.5 mm, and the capacity of the battery cell body is greater than or equal to 30 Ah and less than or equal to 70 Ah.

[0017] This utility model provides a power-type soft-pack battery cell structure, the advantages of which are as follows: the battery cell assembly of the soft-pack battery cell structure is encapsulated in an aluminum-plastic film to form the battery cell body. The aluminum-plastic film has a top sealing area at both the positive and negative electrode positions. The top sealing area is concave, and the concave opening of the top sealing area faces the interior of the aluminum-plastic film. Compared with the prior art, this application optimizes the top sealing area structure by using a concave top sealing area as the top sealing head, avoiding the problem of corner wrinkles in the L-shaped sealing area of ​​the convex top sealing head, and improving the consistency of the top sealing thickness and the sealing performance.

[0018] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0019] The above and other objects, features and advantages of the present invention will become more apparent from the accompanying drawings, in which like reference numerals generally represent like parts.

[0020] Figure 1 A schematic diagram of a power-type soft-pack battery cell structure after removing the aluminum-plastic film outer packaging is shown according to an embodiment of the present invention.

[0021] Figure 2 A schematic diagram of the positive electrode structure of a power-type soft-pack battery cell according to an embodiment of the present invention is shown;

[0022] Figure 3 This diagram shows a schematic of a power-type soft-pack battery cell structure according to an embodiment of the present invention, with the air bag not removed.

[0023] Figure 4 A schematic diagram of an existing pouch cell structure is shown. Figure 1 ;

[0024] Figure 5 A schematic diagram of an existing pouch cell structure is shown. Figure 2 ;

[0025] Figure 6 A schematic diagram of the four-corner pre-cut structure of a power-type soft-pack battery cell according to an embodiment of the present invention is shown;

[0026] Figure 7 The diagram shows a power-type soft-pack battery cell structure after corner cutting and side folding according to an embodiment of the present invention.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Battery cell assembly; 2. Positive electrode sheet; 3. Negative electrode sheet; 4. Separator; 5. Positive electrode tab; 6. Negative electrode tab; 7. Aluminum-plastic film; 8. Top sealing area; 9. Side sealing area; 10. Flat sealing area; 11. Slanted sealing area; 12. Pre-sealed area; 13. Air bag; 14. Unsealed area. Detailed Implementation

[0029] Preferred embodiments of the present invention will now be described in more detail. While preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0030] like Figure 1 , Figure 3 , Figure 6 and Figure 7 This utility model provides a power-type soft-pack battery cell structure, which includes:

[0031] The battery cell assembly 1 includes a positive electrode 2, a negative electrode 3 and a separator 4. The positive electrode 2 and the negative electrode 3 are stacked and arranged, and the separator 4 is disposed between the positive electrode 2 and the negative electrode 3. The positive electrode 2 and the negative electrode 3 are respectively connected to a positive electrode tab 5 and a negative electrode tab 6, which are disposed at both ends of the battery cell assembly 1.

[0032] The aluminum-plastic film 7 and the battery cell assembly 1 are encapsulated in the aluminum-plastic film 7 to form the battery cell body. The aluminum-plastic film 7 has a top sealing area 8 at the position of the positive electrode 5 and the negative electrode 6. The top sealing area 8 is concave and the notch of the concave top sealing area 8 faces the inside of the aluminum-plastic film 7. The aluminum-plastic film 7 has side sealing areas 9 on both sides.

[0033] Specifically, to address the current practice of using a convex top seal and L-shaped sealing areas on both sides of the top seal to improve the volumetric energy density of pouch cells, the top seal area employs a convex top seal head. However, when the aluminum-plastic film is heated and deformed, wrinkles easily form at the corners of the L-shaped sealing area, making it difficult to ensure consistent sealing thickness and affecting the sealing performance. This invention provides a power-type pouch cell structure where the positive electrode tab 5 is connected to the positive electrode plate 2 via ultrasonic welding, and the negative electrode tab 6 is connected via ultrasonic welding. Connected to the negative electrode 3, the battery cell assembly 1 of the soft-pack battery cell structure is encapsulated in the aluminum-plastic film 7 to form the battery cell body. The aluminum-plastic film 7 has a top sealing area 8 at the positions of the positive electrode tab 5 and the negative electrode tab 6. The top sealing area 8 is concave, and the concave top sealing area 8 faces the inside of the aluminum-plastic film 7. Compared with the prior art, this application optimizes the structure of the top sealing area 8, and uses the concave top sealing area 8 as the top sealing head for top sealing, avoiding the problem of corner wrinkles in the L-shaped sealing area of ​​the convex top sealing head, and improving the consistency of the top sealing thickness and the sealing performance.

[0034] Preferably, the top sealing area 8 includes a flat sealing area 10 and an oblique sealing area 11 located on both sides of the notch, and the sealing positions at the four corners of the battery cell body are obliquely cut to form a cut edge.

[0035] Specifically, the flat sealing area 10 is the area between the inner and outer planes of the concave top sealing area 8.

[0036] Preferably, the angle between the horizontal side of the flat sealing area 10 and the oblique side of the oblique sealing area 11 is between 135° and 170°.

[0037] Preferably, the cut edge is parallel to the oblique edge of the oblique sealing area 11, and the width of the oblique sealing area 11 is less than or equal to the width of the flat sealing area 10.

[0038] Specifically, the width of at least one oblique sealing area 11 can be designed to be smaller than the width of the flat sealing area 10, and this area can be designed as a weak sealing area to serve as a pressure relief port for thermal runaway of the soft-pack battery cell.

[0039] Preferably, the width of the flat sealing area 10 is 5-8mm, the width of the oblique sealing area 11 is 2-8mm, the length of the oblique side projection of the oblique sealing area 11 in the side direction of the battery cell body is 5-10mm, and the length of the oblique side projection of the oblique sealing area 11 in the end direction of the battery cell body is 10-50mm.

[0040] Specifically, such as Figure 3 , Figure 6 and Figure 7As shown, the width of the flat sealing area 10 is L2, which is 5-8mm. The width of the oblique sealing area 11 after the four corners are cut is L1, which is 2-8mm. The length of the oblique side projection of the oblique sealing area 11 on the side of the battery cell body is L3, which is 5-10mm. The length of the oblique side projection of the oblique sealing area 11 on the end of the battery cell body is L4, which is 10-50mm.

[0041] Preferably, the ratio of the length of the battery cell body to the width of the battery cell body is less than or equal to 1.25.

[0042] Specifically, to address the issue that existing pouch cells with opposite-side tabs typically have a length-to-width ratio between 1.35 and 5, which is relatively large, leading to uneven current distribution and heat generation in high-power applications, thus affecting the cell's cycle life and safety performance, this application optimizes the cell length ratio and the tab width / cell width ratio. Figure 7 As shown, the length of the battery cell body is L, the width of the battery cell body is W, and the ratio of the length L to the width W of the battery cell body satisfies L / W≤1.25.

[0043] Preferably, the width of the positive electrode tab 5 is greater than or equal to the width of the negative electrode tab 6, and the ratio of the width of the negative electrode tab 6 to the width of the battery cell body is greater than or equal to 0.5.

[0044] Specifically, such as Figure 7 As shown, the width of the positive electrode tab 5 is A, the width of the negative electrode tab 6 is B, and the ratio of the width of the negative electrode tab B to the width of the cell body W satisfies B / W≥0.5.

[0045] Preferably, the ratio of the length to the width of the positive electrode 2 is less than or equal to 1.1, the length of the negative electrode 3 is 1-4 mm longer than the length of the positive electrode 2, and the width of the negative electrode 3 is 1-4 mm wider than the width of the positive electrode 2.

[0046] Specifically, such as Figure 2 As shown, the length of the positive electrode 2 is C and the width is K. The ratio of the length C of the positive electrode 2 to the width K of the positive electrode 2 satisfies C / K≤1.1.

[0047] Preferably, the ratio of the product of the length and width of the battery cell to the thickness of the battery cell is greater than or equal to 4300 mm, and the ratio of the product of the length and width of the battery cell to the energy of the battery cell is greater than or equal to 200 mm. 2 / Wh.

[0048] Specifically, the ratio of the product of the length L and width W of the battery cell to the thickness of the battery cell satisfies L*W / T ≥ 4300 mm, and the ratio of the product of the length L and width W of the battery cell to the energy E of the battery cell satisfies L*W / E ≥ 200 mm. 2 / Wh.

[0049] Preferably, the width of the battery cell body is greater than or equal to 185 mm and less than or equal to 210 mm, the length of the battery cell body is greater than or equal to 200 mm and less than or equal to 260 mm, the thickness of the battery cell body is greater than or equal to 5 mm and less than or equal to 10.5 mm, and the capacity of the battery cell body is greater than or equal to 30 Ah and less than or equal to 70 Ah.

[0050] Specifically, the width W of the battery cell body satisfies 185mm≤W≤210mm, the length L of the battery cell body satisfies 200mm≤L≤260mm, the thickness T of the battery cell body satisfies 5mm≤T≤10.5mm, and the capacity of the battery cell body satisfies 30Ah≤capacity≤70Ah.

[0051] Preferably, during the manufacturing process of the soft-pack battery cell structure, a pre-sealing area 12 is first provided on one side of the aluminum-plastic film 7, and an air bag 13 is provided between one side of the aluminum-plastic film 7 and the battery cell assembly 1.

[0052] Specifically, after the soft-pack battery cell structure is formed, the air bag 13 on one side of the aluminum-plastic film 7 is cut to form the side sealing area 9. A cut edge is formed during the cutting process, along which... Figure 6 Cut the aluminum-plastic film at the four corners as shown by the dotted line, then fold the edge of the side sealing area 9 to finally obtain the battery cell body.

[0053] In summary, the power-type pouch cell structure of this application optimizes the cell aspect ratio and the ratio of tab width to cell width, and designs a better range of cell size and capacity. Compared with the existing pouch cell structure with tabs on the opposite side (where the ratio of cell length L to cell width W satisfies 1.35≤L / W≤5), the electron transmission path is shorter, the current carrying capacity is better, and the current distribution and temperature rise are more uniform.

[0054] For soft-pack cells with a length-to-width ratio ≤ 1.25, the top sealing area structure was optimized. A concave top sealing area 8 was used as the top sealing head to avoid the problem of sealing corner wrinkles and improve the thickness consistency and sealing performance of the top sealing area 8.

[0055] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A power-type soft-pack battery cell structure, characterized in that, The pouch cell structure includes: A battery cell assembly, comprising a positive electrode, a negative electrode, and a separator, wherein the positive electrode and the negative electrode are stacked, the separator is disposed between the positive electrode and the negative electrode, the positive electrode and the negative electrode are respectively connected to a positive tab and a negative tab, and the positive tab and the negative tab are disposed at both ends of the battery cell assembly; The aluminum-plastic film is used to encapsulate the battery cell assembly to form the battery cell body. The aluminum-plastic film has a top sealing area at the positions of the positive and negative tabs. The top sealing area is concave, with the opening of the concave top sealing area facing the interior of the aluminum-plastic film. The top sealing area includes a flat sealing area and oblique sealing areas located on both sides of the opening. The aluminum-plastic film has side sealing areas on both sides.

2. The power-type soft-pack battery cell structure according to claim 1, characterized in that, The sealing positions at the four corners of the battery cell body are cut diagonally to form cut edges.

3. The power-type soft-pack battery cell structure according to claim 2, characterized in that, The angle between the horizontal side of the flat sealing area and the oblique side of the oblique sealing area is between 135° and 170°.

4. The power-type soft-pack battery cell structure according to claim 2, characterized in that, The cut edge is parallel to the oblique edge of the oblique sealing area, and the width of the oblique sealing area is less than or equal to the width of the flat sealing area.

5. A power-type soft-pack battery cell structure according to claim 2, characterized in that, The width of the flat sealing area is 5-8mm, the width of the oblique sealing area is 2-8mm, the length of the oblique side projection of the oblique sealing area in the side direction of the battery cell body is 5-10mm, and the length of the oblique side projection of the oblique sealing area in the end direction of the battery cell body is 10-50mm.

6. The power-type soft-pack battery cell structure according to claim 1, characterized in that, The ratio of the length of the battery cell body to the width of the battery cell body is less than or equal to 1.

25.

7. The power-type soft-pack battery cell structure according to claim 1, characterized in that, The width of the positive electrode tab is greater than or equal to the width of the negative electrode tab, and the ratio of the width of the negative electrode tab to the width of the battery cell body is greater than or equal to 0.

5.

8. The power-type soft-pack battery cell structure according to claim 1, characterized in that, The ratio of the length to the width of the positive electrode is less than or equal to 1.1, the length of the negative electrode is 1-4 mm longer than the length of the positive electrode, and the width of the negative electrode is 1-4 mm wider than the width of the positive electrode.

9. A power-type soft-pack battery cell structure according to claim 1, characterized in that, The ratio of the product of the length and width of the battery cell body to the thickness of the battery cell body is greater than or equal to 4300 mm, and the ratio of the product of the length and width of the battery cell body to the energy of the battery cell body is greater than or equal to 200 mm. 2 / Wh.

10. A power-type soft-pack battery cell structure according to claim 1, characterized in that, The width of the battery cell body is greater than or equal to 185mm and less than or equal to 210mm, the length of the battery cell body is greater than or equal to 200mm and less than or equal to 260mm, the thickness of the battery cell body is greater than or equal to 5mm and less than or equal to 10.5mm, and the capacity of the battery cell body is greater than or equal to 30Ah and less than or equal to 70Ah.

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