A battery cell and a battery module

Abstract

This utility model discloses a battery cell and a battery module, belonging to the field of power battery technology. It includes a first housing, a cover plate assembly, and a second housing connected in sequence. Positive and negative terminals are respectively installed on the front and rear sides of the cover plate assembly. At least one pair of battery modules with terminals at both ends are disposed within both the first and second housings. The positive terminals of half of the battery modules within the first and second housings are electrically connected to the positive terminals, and the negative terminals of the other half are electrically connected to the negative terminals. The terminals of all battery modules away from the cover plate assembly are welded together. By eliminating the keel support, the internal space occupied by the battery cell is reduced. The positive and negative terminals are positioned in the middle of the battery cell, and the cover plate assembly is placed at the location of the intermediate busbar in existing technologies. This reduces the internal space occupied at both ends of the battery cell, thereby improving the space utilization and energy density of the battery cell.

Description

Technical Field

[0001] This utility model relates to the field of energy storage battery technology, specifically to a battery cell and a battery module. Background Technology

[0002] Lithium-ion batteries are widely used due to their high energy density, lack of memory effect, long cycle life per cell, high efficiency, cleanliness, and pollution-free characteristics. In recent years, driven by both policy and cost competition, new energy technologies need to continuously move towards lower costs and simpler manufacturing processes. With the rapid expansion of the energy storage market, large capacity has become a crucial development direction for lithium-ion batteries for energy storage. Currently, the main manufacturing processes for energy storage batteries include prismatic, cylindrical, and pouch cells. Among these, pouch cells are gaining increasing attention due to their larger heat dissipation area, stronger safety buffering capacity, and superior packaging flexibility; however, their individual cell capacity is relatively small, requiring more cells to be connected in series for assembly.

[0003] Based on this, Chinese patent application 202222787683.2 proposes a soft-pack cell module and a soft-pack battery, disclosing a technical solution that involves setting a keel support within a casing, and arranging multiple cell modules on both sides of the keel support. Adjacent cell modules are electrically connected via an intermediate busbar, and the tabs of the cell modules near the end of the casing are pre-folded and then welded to the input panel. Although this technical solution can increase the capacity of a single cell, the presence of the keel support limits the energy density of the solution, leaving room for improvement. Utility Model Content

[0004] The purpose of this utility model is to provide a battery cell that solves the problem of low energy density in existing batteries mentioned in this application.

[0005] To achieve the above objectives, this utility model provides a battery cell comprising a first housing, a cover assembly, and a second housing connected in sequence. Positive and negative terminals are respectively mounted on the front and rear sides of the cover assembly. At least one pair of battery modules with connected terminals and tabs are disposed within both the first and second housings. In the first housing, the positive terminals of half of the battery modules are electrically connected to the positive terminals, and the negative terminals of the other half are electrically connected to the negative terminals. The terminals of all battery modules at the ends furthest from the cover assembly are welded together. Similarly, in the second housing, the positive terminals of half of the battery modules are electrically connected to the positive terminals, and the negative terminals of the other half are electrically connected to the negative terminals. The terminals of all battery modules at the ends furthest from the cover assembly are welded together. By eliminating the keel support, the internal space occupied by the battery cell is reduced. Furthermore, by placing the positive and negative terminals in the middle of the battery cell and using the cover assembly at the location of the intermediate busbar in existing technologies, the internal space occupied at both ends of the battery cell can be reduced, thereby improving the space utilization and energy density of the battery cell.

[0006] Furthermore, the cover plate assembly includes a front cover plate, a rear cover plate, an upper cover plate, and a lower cover plate. A recessed portion is provided in the middle regions of the front cover plate and the rear cover plate. The positive electrode post and the negative electrode post are respectively provided on the recessed portions of the front cover plate and the rear cover plate. The outer end face heights of the positive electrode post and the negative electrode post are equal to or lower than the front and rear side faces of the first housing and the second housing. By arranging the positive electrode post and the negative electrode post in the recessed portions, the occupation of the battery cell on the battery pack space during the grouping process can be reduced, and the structural strength of the front cover plate and the rear cover plate with the recessed portions in the vertical direction is enhanced, which can improve the strength performance of the battery cell.

[0007] Furthermore, positioning steps corresponding to the upper cover plate and the lower cover plate are respectively provided on the inner sides of the upper and lower ends of the front cover plate and the rear cover plate for positioning and supporting the upper cover plate and the lower cover plate. The step difference of the positioning step is a, and the thicknesses of the upper cover plate and the lower cover plate are b, -0.05 mm ≤ b - a ≤ 0.1 mm. This difference needs to be within the acceptable range of the welding process, otherwise it will affect the normal welding of the upper cover plate, the lower cover plate with the front cover plate and the rear cover plate.

[0008] Furthermore, insertion plates extending along the sides are provided at the left and right ends of the front cover plate, the rear cover plate, the upper cover plate, and the lower cover plate. This side refers to the side where the front cover plate, the rear cover plate, the upper cover plate, and the lower cover plate are welded to the first housing and the second housing. The setting of the insertion plates can, on the one hand, guide during the assembly of the cover plate assembly with the first housing and the second housing, and can also block welding slag from entering the interior of the battery cell when the cover plate assembly is welded to the first housing and the second housing, and can also play a role in strengthening the structure, providing support to the openings of the first housing and the second housing from the inside.

[0009] Furthermore, the ends of the first housing and the second housing close to the cover plate assembly are provided with openings, and the wall thickness at the openings is c. There is a step difference d between the insertion plates and the outer walls of the front cover plate, the rear cover plate, the upper cover plate, and the lower cover plate, 0 < d - c ≤ 0.2 mm. The step difference d cannot be less than the wall thickness c at the openings of the first housing and the second housing, otherwise it will affect the normal assembly of the cover plate assembly with the first housing and the second housing.

[0010] Furthermore, an insulating plate is provided between the upper cover plate and the lower cover plate to prevent the positive and negative electrode tabs from contacting and short - circuiting here.

[0011] Furthermore, explosion - proof valves are provided on the end faces of the first housing and the second housing far from the cover plate assembly for pressure relief and explosion prevention.

[0012] This utility model also provides a battery module, including a plurality of the above-mentioned battery cells. Two adjacent battery cells are arranged side by side and connected in series or in parallel through conductive components. Since the height of the outer end face of the positive and negative terminals is equal to or lower than the front and rear sides of the first and second housings, if the positive terminal of one of the two adjacent battery cells is directly connected to the negative terminal of the other battery cell to achieve series connection, the electrical connection is not stable. The setting of conductive components can improve the reliability of the electrical connection. Both ends of the battery cells are provided with exhaust channels communicating with the explosion-proof valve to guide the gas ejected from the explosion-proof valve.

[0013] Furthermore, the top and / or bottom of the cover plate assembly are lower than the upper and lower sides of the first and second housings for the passage of conductive elements such as busbars.

[0014] Furthermore, the top and bottom of the cover plate assembly are flush with the upper and lower sides of the first and second housings, and the top and / or bottom of the cover plate assembly are provided with at least one clearance groove for conductive components to pass through. Without reducing the height of the upper and lower cover plates relative to the sides of the first and second housings, conductive components such as busbars can also pass through by opening the clearance groove.

[0015] This invention reduces the space occupied by the battery cell by eliminating the keel support and placing the positive and negative terminals in the middle of the battery cell. It also provides a cover plate assembly at the position of the intermediate busbar in the prior art, which reduces the space occupied at both ends of the battery cell and thus improves the space utilization and energy density of the battery cell. Attached Figure Description

[0016] The dimensions and scales in the accompanying drawings do not represent the actual dimensions and scales of the product. The drawings are for illustrative purposes only, and some non-essential elements or features have been omitted for clarity.

[0017] Figure 1 This is a schematic diagram of the structure of the battery cell of this utility model;

[0018] Figure 2 This is a schematic diagram of the internal battery module of the battery cell of this utility model;

[0019] Figure 3 This is a schematic diagram of the cover plate assembly in the battery cell of this utility model;

[0020] Figure 4 yes Figure 3 Enlarged structural diagram at point E;

[0021] Figure 5 This is a schematic diagram of the structure of the first casing in the battery cell of this utility model;

[0022] Figure 6 yes Figure 5 Enlarged structural diagram at point F;

[0023] Figure 7 This is a partial structural cross-sectional view of two adjacent battery cells assembled into a group in this utility model (battery module not shown).

[0024] Figure 8 yes Figure 7 Enlarged structural diagram at point G;

[0025] Figure 9 yes Figure 7 Enlarged structural diagram at point H;

[0026] Figure 10 This is a schematic diagram of the battery module of this utility model;

[0027] Figure 11 This is a structural schematic diagram of the cover plate assembly in the battery module of this utility model.

[0028] Explanation of reference numerals in the attached figures

[0029] 1. First housing; 2. Cover plate assembly; 21. Positive terminal; 22. Negative terminal; 23. Front cover plate; 24. Rear cover plate; 25. Upper cover plate; 26. Lower cover plate; 27. Recess; 211. Positioning step; 212. Insert plate; 3. Second housing; 4. Battery module; 5. Explosion-proof valve; 6. Conductive component; 7. Exhaust channel; 8. Clearance groove. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings. The embodiments described herein are merely preferred embodiments of the present invention. Those skilled in the art can conceive of other ways to implement the present invention based on the preferred embodiments, and such other ways also fall within the scope of the present invention.

[0031] Example 1

[0032] Reference Figures 1-9A battery cell includes a first housing 1, a cover plate assembly 2, and a second housing 3 connected in sequence. A positive terminal 21 and a negative terminal 22 are respectively installed on the front and rear sides of the cover plate assembly 2. At least one pair of battery modules 4 with terminals are provided in both the first housing 1 and the second housing 3. The battery modules 4 are soft-pack battery modules encapsulated with aluminum-plastic film. The positive terminal of half of the battery modules 4 is electrically connected to the positive terminal 21, and the negative terminal of the other half of the battery modules 4 is electrically connected to the negative terminal 22. The terminals of all battery modules 4 at the end away from the cover plate assembly 2 are welded together. Taking a pair of battery modules 4 set in both the first housing 1 and the second housing 3 as an example, the pair of battery modules 4 are stacked in the first housing 1 and both have a structure with tabs at both ends. The positive tab of one battery module 4 is welded to the positive terminal 21, and the negative tab of the other battery module 4 is welded to the negative terminal 22. The negative and positive tabs at the ends away from the cover plate assembly 3 are welded together in series. The pair of battery modules 4 in the second housing 3 are set in the same way. The two positive tabs welded together to the positive terminal 21 can be connected to the positive terminal 21 by butterfly welding. The two negative tabs welded together to the negative terminal 22 can also be connected to the negative terminal 22 by butterfly welding. This can reduce the length of the tabs and further improve the space utilization rate within the battery cell. With the above configuration, two sets of stacked battery modules 4 are arranged along the length of the battery cell, and the cover plate assembly 2 is used to connect and support them in the middle. Compared with the prior art in the background art, the keel support can be eliminated while ensuring structural strength, reducing the occupation of the internal space of the battery cell. The positive terminal 21 and negative terminal 22 are set in the middle of the battery cell. The intermediate busbar is eliminated and the cover plate assembly 3 is set, which can also reduce the occupation of the internal space at both ends of the battery cell, thereby improving the space utilization and energy density of the battery cell.

[0033] The cover plate assembly 2 includes a front cover plate 23, a rear cover plate 24, an upper cover plate 25, and a lower cover plate 26. The middle regions of the front cover plate 23 and the rear cover plate 24 are provided with recesses 27. The positive electrode post 21 and the negative electrode post 22 are respectively provided on the recesses 27 of the front cover plate 23 and the rear cover plate 24. The height of the outer end face of the positive electrode post 21 and the negative electrode post 22 is equal to or lower than the front and rear sides of the first housing 1 and the second housing 3. By providing the positive electrode post 21 and the negative electrode post 22 in the recesses 27, the space occupied by the battery cells in the battery pack during the assembly process can be reduced. Moreover, the structural strength of the front cover plate 23 and the rear cover plate 24 with the recesses 27 is enhanced in the vertical direction, which can improve the overall strength performance of the battery cells. Therefore, the keel support can be eliminated.

[0034] On the inner sides of the upper and lower ends of the front cover plate 23 and the rear cover plate 24, positioning steps 211 corresponding to the upper cover plate 25 and the lower cover plate 26 are respectively provided for positioning and supporting the upper cover plate 25 and the lower cover plate 26. The step difference of the positioning step 211 is a, that is, the distance from the step surface to the upper and lower edges of the front cover plate 23 and the rear cover plate 24. The thickness of the upper cover plate 25 and the lower cover plate 26 is b, and -0.05mm ≤ b - a ≤ 0.1mm. This difference needs to be within the acceptable range of the welding process, otherwise it will affect the normal welding of the upper cover plate 25, the lower cover plate 26 with the front cover plate 23 and the rear cover plate 24.

[0035] On the left and right ends of the front cover plate 23, the rear cover plate 24, the upper cover plate 25 and the lower cover plate 26, insertion plates 212 extending along the side edges are provided. The side edge refers to the side edge where the front cover plate 23, the rear cover plate 24, the upper cover plate 25 and the lower cover plate 26 are welded to the first housing 1 and the second housing 2. The setting of the insertion plates 212 can, on the one hand, guide during the assembly of the cover plate assembly 2 with the first housing 1 and the second housing 3, and can also block welding slag from entering the interior of the battery cell when the cover plate assembly 2 is welded to the first housing 1 and the second housing 3, and can also play a role in strengthening the structure and support the openings of the first housing 1 and the second housing 2 from the inside.

[0036] The first housing 1 and the second housing 3 are provided with openings at the ends close to the cover plate assembly 2, and the wall thickness at the opening is c. There is a step difference d between the insertion plates 212 and the outer walls of the front cover plate 23, the rear cover plate 24, the upper cover plate 25 and the lower cover plate 26, and 0 < d - c ≤ 0.2mm. The step difference d cannot be less than the wall thickness c at the openings of the first housing 1 and the second housing 3, otherwise it will affect the normal assembly of the cover plate assembly 2 with the first housing 1 and the second housing 3.

[0037] An insulating plate 28 is provided between the upper cover plate 25 and the lower cover plate 26 to prevent the positive and negative electrode tabs from contacting and short - circuiting here.

[0038] Explosion - proof valves 5 are provided on the end faces of the first housing 1 and the second housing 3 far from the cover plate assembly 2 for pressure relief and explosion prevention.

[0039] See Figure 9 and Figure 10This utility model also provides a battery module, including several battery cells as described above. Two adjacent battery cells are arranged side by side and connected in series or in parallel through a conductive element 6. The conductive element 6 can be a U-shaped elastic metal sheet, an FPC cable, a busbar, or other busbar element. Since the height of the outer end face of the positive terminal 21 and the negative terminal 22 is equal to or lower than the front and rear sides of the first housing 1 and the second housing 3, if the positive terminal 24 of one of the two adjacent battery cells is directly connected to the negative terminal 22 of the other battery cell to achieve series connection, the electrical connection relationship is not stable. The setting of the conductive element 6 can improve the reliability of its electrical connection. Both ends of the battery cell are provided with an exhaust channel 7 communicating with the explosion-proof valve 5 to guide the gas ejected from the explosion-proof valve 5.

[0040] The top and / or bottom of the cover assembly 3 are lower than the upper and lower sides of the first housing 1 and the second housing 3, so as to realize the series or parallel connection of adjacent battery cells through conductive components 6 such as busbars.

[0041] See Figure 11 The top and / or bottom of the cover assembly 3 are provided with at least one clearance groove 8 for the passage of conductive components 6. Without reducing the height of the top and / or bottom of the cover assembly 3 relative to the sides of the first housing 1 and the second housing 3, the clearance groove 8 allows for the series or parallel connection of adjacent battery cells through conductive components such as busbars. The top and bottom of the cover assembly 3 are flush with the upper and lower sides of the first housing 1 and the second housing 3, which can improve the support strength of the battery cell center for the overall battery pack.

[0042] In the description of this utility model, it should be noted that the terms "front," "rear," "left," "right," "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and 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, and therefore should not be construed as a limitation on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0044] The scope of protection of this utility model is defined only by the claims. Thanks to the teachings of this utility model, those skilled in the art will readily recognize that alternative structures to the disclosed structure can be used as feasible alternative implementations, and that the disclosed implementations can be combined to produce new implementations, which also fall within the scope of the appended claims.

Claims

1. A battery cell, characterized by, The device includes a first housing, a cover plate assembly, and a second housing connected in sequence. Positive and negative terminals are respectively installed on the front and rear sides of the cover plate assembly. Each of the first and second housings contains at least one pair of battery modules with terminals at both ends. In the first housing, the positive terminals of half of the battery modules are electrically connected to the positive terminals, and the negative terminals of the other half are electrically connected to the negative terminals. The terminals of all battery modules at the end furthest from the cover plate assembly are welded together. Similarly, in the second housing, the positive terminals of half of the battery modules are electrically connected to the positive terminals, and the negative terminals of the other half are electrically connected to the negative terminals. The terminals of all battery modules at the end furthest from the cover plate assembly are welded together.

2. The battery cell of claim 1, wherein, The cover plate assembly includes a front cover plate, a rear cover plate, an upper cover plate, and a lower cover plate. The middle regions of the front cover plate and the rear cover plate are provided with recessed portions. The positive terminal and the negative terminal are respectively disposed on the recessed portions of the front cover plate and the rear cover plate. The height of the outer end faces of the positive terminal and the negative terminal is equal to or lower than the front and rear sides of the first housing and the second housing.

3. The battery cell of claim 2, wherein, The inner sides of the upper and lower ends of the front cover plate and the rear cover plate are respectively provided with positioning steps corresponding to the upper cover plate and the lower cover plate. The step difference of the positioning steps is a, and the thickness of the upper cover plate and the lower cover plate is b, -0.05mm≤ba≤0.1mm.

4. The battery cell of claim 2, wherein, The front cover, rear cover, upper cover, and lower cover are all provided with insert plates extending along the sides at both ends.

5. The battery cell of claim 4, wherein, The first and second housings have openings at their ends near the cover plate assembly, with a wall thickness of c at the opening. A gap d exists between the insert plate and the outer walls of the front cover plate, rear cover plate, upper cover plate, and lower cover plate. <d-c≤0.2mm。 6. The battery cell of claim 2, wherein, An insulating plate is provided between the upper cover plate and the lower cover plate.

7. The battery cell according to any one of claims 1 to 6, characterized in that An explosion-proof valve is provided on the end face of the first housing and the second housing away from the cover plate assembly.

8. A battery module comprising a plurality of battery cells as described in any one of claims 1-7, characterized in that, Two adjacent battery cells are arranged side by side and connected in series or parallel through conductive components. Both ends of each battery cell are provided with an exhaust channel that communicates with an explosion-proof valve.

9. The battery module of claim 8, wherein, The top and / or bottom of the cover assembly are lower than the upper and lower sides of the first and second housings.

10. The battery module of claim 8, wherein, The top and bottom of the cover plate assembly are flush with the upper and lower sides of the first and second housings, and the top and / or bottom of the cover plate assembly are provided with at least one clearance groove for the passage of conductive components.

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