Battery shell and square lithium battery

Abstract

The utility model provides a battery shell and a square lithium battery, and relates to the technical field of battery, the battery shell comprises an outer shell, the outer shell is provided with an accommodating space with a top opening, the middle part of the accommodating space is provided with an inner shell along the length direction of the outer shell, and two ends of the inner shell are respectively and fixedly connected with the inner wall of the accommodating space; the inner shell is provided with a hollow channel penetrating through the outer shell, and the inner shell divides the containing space into two containing cavities used for installing a core package in the width direction of the outer shell. The two core packages are separated through the inner shell, heat, close to the middle of the shell, of the core packages can be released through the hollow channel in time, meanwhile, the hollow channel of the inner shell can serve as a cooling channel and allows a heat exchange medium to pass through, and therefore heat exchange is effectively conducted on the core packages in the battery, rapid cooling can be achieved, and the service life of the battery is prolonged. And the phenomena of overheating and thermal runaway are prevented, the core package can be heated, lithium precipitation caused by too low temperature during charging is prevented, and the heat transfer performance is greatly improved.

Description

Technical Field

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

[0002] Currently, in the fields of power and energy storage, large square aluminum shell lithium-ion batteries have become the mainstream. However, with the continuous upgrading of the industry and the intensification of market competition, the requirements for the capacity and rate capabilities of single batteries are increasing day by day. However, the capacity per gram of the main raw materials of lithium batteries, lithium iron phosphate and nickel cobalt manganese ternary materials, has limited room for improvement, and both have theoretical upper limits for the capacity per gram.

[0003] To improve the capacity and rate capabilities of single lithium batteries, battery manufacturers generally adopt higher positive and negative electrode surface densities and compaction densities in the design. At the same time, the size of single lithium batteries is constantly increasing, and the thickness of the housing also increases accordingly. However, with the increase in battery thickness, the prior art faces the following several significant disadvantages: 1. Heat conduction problem: The greater the battery thickness, the lower the heat conduction efficiency. Whether using air cooling or liquid cooling methods, it is difficult to effectively dissipate the heat inside the battery cell. During high-rate charge and discharge processes, the generated heat will further exacerbate this problem, resulting in an increase in the internal temperature of the battery, a shortening of the cycle life, and even potential safety hazards such as thermal runaway. 2. Low-temperature performance problem: In a low-temperature environment, the heat transfer efficiency of battery surface heating is low, and the internal temperature rises slowly. During the charging process, insufficient internal temperature is likely to cause lithium plating phenomenon, and lithium dendrites formed by long-term accumulation may pierce the diaphragm, leading to battery short circuit and thus triggering serious safety problems. Summary of the Utility Model

[0004] In view of this, the utility model provides a battery housing and a square lithium battery to solve the problem of insufficient internal heat transfer performance of large square aluminum shell batteries.

[0005] The technical solution of the utility model is realized as follows:

[0006] In the first aspect, the utility model provides a battery housing, including an outer shell, the outer shell having a receiving space with an open top, an inner shell being disposed in the middle of the receiving space along the length direction of the outer shell, both ends of the inner shell being fixedly connected to the inner wall of the receiving space, the inner shell having a hollow channel penetrating the outer shell, and the inner shell dividing the receiving space into two receiving cavities for installing core packages along the width direction of the outer shell.

[0007] Based on the above technical solution, preferably, there is a gap between the inner shell and the bottom surface of the receiving space for communicating the two receiving cavities with each other.

[0008] Based on the above technical solution, preferably, the width of the inner shell is greater than 1 mm and less than 2 / 3 of the thickness of the outer shell.

[0009] Based on the above technical solution, preferably, a plurality of partition plates are vertically arranged at equal intervals along the length direction of the outer shell inside the hollow channel, the partition plates are fixedly connected perpendicular to the inner wall of the hollow channel, and a plurality of through holes are arranged at equal intervals along the height direction of the partition plates.

[0010] In a second aspect, the present utility model discloses a square lithium battery, which includes a cover plate assembly, a core package, and the battery housing described in the first aspect. At least one core package is arranged in the accommodation cavity. The cover plate assembly is fixedly connected to the opening end of the outer shell and is electrically connected to the core package.

[0011] Based on the above technical solution, preferably, the top end of the inner shell is flush with or lower than the top surface of the core package.

[0012] Based on the above technical solution, preferably, the cover plate assembly includes a top cover, a pole column, a lower plastic part, and a transfer piece. The lower plastic part is fixedly arranged on the bottom surface of the top cover. The pole column is fixedly connected to the top cover in an insulated manner. The transfer piece is arranged on the side of the lower plastic part away from the top cover. A convex part is provided at the center of the side of the transfer piece facing the lower plastic part. The convex part is welded to the pole column. Welding areas are respectively provided on the surfaces of the transfer piece on both sides of the convex part along the width direction of the top cover. The welding areas are welded to the pole ears on the core package.

[0013] Further, preferably, a groove corresponding to the position of the convex part is provided on the side of the transfer piece away from the lower plastic part.

[0014] The present utility model has the following beneficial effects compared with the prior art:

[0015] (1) Through the setting of the inner shell, the accommodation space is divided into two accommodation cavities, so that there is an isolation structure between the two core packages. The hollow channel design of the inner shell can be used as a cooling channel, allowing coolant or cooling air to pass through, thereby effectively discharging the heat generated inside the battery, helping to evenly disperse the heat, reducing the temperature inside the battery, preventing overheating and thermal runaway phenomena, and greatly improving the heat transfer performance. In a low-temperature environment, through the setting of the hollow channel, it can be used to guide the heat of the heating element into the battery interior, improve the temperature rise efficiency of the battery in a low-temperature environment, reduce the lithium plating phenomenon, and avoid the formation of lithium dendrites, thereby improving the low-temperature performance and safety of the battery.

[0016] (2) By setting up the partition plate, the structural strength of the inner shell can be improved, preventing the two surfaces of the hollow channel from deforming under the force caused by the expansion of the core package during charge and discharge. At the same time, it can also prevent deformation caused by external impact or vibration, thus enhancing the overall strength and stability of the battery housing. The partition plate is provided with a plurality of through holes at equal intervals along its height direction, which can promote the flow of the heat exchange medium (such as air or coolant) in the hollow channel. Through the uniformly distributed through holes, the heat exchange medium can more effectively conduct heat exchange with the inside of the battery, improving the heat exchange effect.

[0017] (3) By respectively providing welding areas on the surfaces of the connecting pieces on both sides of the convex part along the width direction of the top cover, the convex part is welded to the pole column, and the welding areas are respectively welded to the pole ears. This makes the welding points between the pole ears and the connecting pieces and the welding points between the connecting pieces and the pole column on the axis perpendicular to the width direction of the top cover, thus realizing the welding between the connecting piece and the pole column and the welding between the connecting piece and the pole ear in a straight line. The current can be conducted from the pole ear to the pole column through the connecting piece along the shortest path. Such a design greatly reduces the path length in current transmission, avoids detours or complex current flow routes, and reduces the internal resistance. In addition, the shortening of the current path means that the energy transmission efficiency of the battery during operation is improved. Especially during fast charging or high-power output, the reduction of the internal resistance can effectively reduce the heat generation phenomenon and enhance the safety and stability of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 is a three-dimensional structural schematic diagram of the battery housing disclosed by the present invention;

[0020] Figure 2 is a top view of the battery housing disclosed by the present invention;

[0021] Figure 3 is Figure 2 a plane cross-sectional view at A-A in

[0022] Figure 4 is Figure 2 a plane cross-sectional view at B-B in

[0023] Figure 5 is an exploded schematic diagram of the square lithium battery disclosed by the present invention;

[0024] Figure 6Top view of the square lithium battery disclosed by the present utility model;

[0025] Figure 7 is Figure 6 the sectional view taken along the plane at C-C in

[0026] Figure 8 is Figure 7 the partial enlarged view at D in

[0027] Reference numerals:

[0028] 1. Outer shell; 11. Accommodating space; 2. Inner shell; 21. Hollow channel; 110. Receiving cavity; 22. Partition; 221. Through hole; 3. Cover plate assembly; 4. Core package; 41. Tab; 31. Top cover; 32. Terminal; 33. Lower plastic part; 34. Adapter plate; 341. Protrusion; 342. Welding area; 343. Groove. Detailed implementation manners

[0029] Next, in combination with the implementation manners of the present utility model, the technical solutions in the implementation manners of the present utility model will be clearly and completely described. Obviously, the described implementation manners are only a part of the implementation manners of the present utility model, rather than all the implementation manners. Based on the implementation manners in the present utility model, all other implementation manners obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0030] As Figure 1 shown, in combination with Figures 2 - 4 , the present utility model discloses a battery housing, including a square-shaped outer shell 1. The outer shell 1 has an accommodating space 11 with an open top. In the middle of the accommodating space 11, a square-shaped inner shell 2 is arranged along the length direction of the outer shell 1. Both ends of the inner shell 2 are fixedly connected to the inner wall of the accommodating space 11. The inner shell 2 has a hollow channel 21 that penetrates the outer shell 1. The inner shell 2 divides the accommodating space 11 into two receiving cavities 110 for installing the core package 4 along the width direction of the outer shell 1.

[0031] By adopting the above technical solutions, through the arrangement of the inner shell 2, the accommodating space 11 is divided into two receiving cavities 110, so that there is an isolation structure between the two core packages 4. The design of the hollow channel 21 of the inner shell 2 can be used as a cooling channel to allow coolant or cooling air to pass through, thereby effectively discharging the heat generated inside the battery, helping to evenly disperse the heat, reducing the temperature inside the battery, preventing overheating and thermal runaway phenomena, and greatly improving the heat transfer performance. In a low-temperature environment, through the arrangement of the hollow channel 21, it can be used to guide the heat of the heating element into the battery, improving the temperature rise efficiency of the battery in a low-temperature environment, reducing the lithium deposition phenomenon, and avoiding the formation of lithium dendrites, thereby improving the low-temperature performance and safety of the battery.

[0032] As some preferred embodiments, there is a gap between the inner shell 2 and the bottom surface of the accommodation space 11, which is used to communicate the two accommodation cavities 110 with each other. With this arrangement, the electrolyte can flow between the two accommodation cavities 110, ensuring that the electrolyte can uniformly infiltrate the two core packages 4.

[0033] As some preferred embodiments, the width of the inner shell 2 is greater than 1 mm and less than 2 / 3 of the thickness of the outer shell 1. By setting the width of the inner shell 2 to exceed 1 mm, it can ensure that the inner shell 2 has sufficient mechanical strength and rigidity to effectively support and fix the core package 4, preventing the structure from loosening or deforming due to vibration and impact during use. Limiting the width of the inner shell 2 within 2 / 3 of the thickness of the outer shell 1 can ensure that the inner shell 2 is not too heavy, thus avoiding excessive influence on the internal space of the overall battery housing and reducing the reduction of the battery energy density.

[0034] As some preferred embodiments, a plurality of partition plates 22 are vertically arranged at equal intervals along the length direction of the outer shell 1 inside the hollow channel 21, and the partition plates 22 are fixedly connected perpendicular to the inner wall of the hollow channel 21. Through the arrangement of the partition plates 22, the structural strength of the inner shell 2 can be improved, preventing the two surfaces of the hollow channel from deforming due to the expansion of the core package during charge and discharge, and at the same time, preventing deformation caused by external impact or vibration, thereby improving the overall strength and stability of the battery housing. A plurality of through holes 221 are arranged at equal intervals along the height direction of the partition plate 22, which can promote the flow of the cooling medium (such as air or coolant) in the hollow channel 21. Through the uniformly distributed through holes 221, the cooling medium can more effectively exchange heat with the inside of the battery, improving the heat exchange effect.

[0035] The present utility model also proposes a square lithium battery, referring to the attached Figures 5 - 8 As shown, it includes a cover plate assembly 3, a core package 4 and the battery housing disclosed in the above embodiments. At least one core package 4 is arranged in the accommodation cavity 110. The cover plate assembly 3 is fixedly connected to the open end of the outer shell 1 and is electrically connected to the core package 4.

[0036] This embodiment shows a structural manner in which one core package 4 is arranged in the accommodation cavity 110. Of course, 2 or more core packages 4 can also be arranged in the accommodation cavity 110, and the sum of the total thicknesses of the multiple core packages 4 is adapted to the width of the accommodation cavity.

[0037] The square lithium battery adopts the battery housing with the above structure. The two core packages 4 are separated by the inner shell 2. The heat of the core package 4 near the middle of the housing can be released in time through the hollow channel 21. At the same time, the hollow channel 21 of the inner shell 2 can be used as a heat exchange channel to allow the heat exchange medium to pass through, so as to effectively exchange heat for the core package 4 inside the battery. That is, it can achieve rapid cooling to prevent overheating and thermal runaway, and can also heat the core package 4 to prevent lithium plating during charging due to too low temperature, greatly improving the heat transfer performance.

[0038] As some preferred embodiments, the top end of the inner shell 2 is flush with or lower than the top surface of the core package 4. With this setting, it can be avoided that the inner shell 2 is too high at the upper end of the accommodation space 11, which may affect the installation of the cover plate assembly 3. At the same time, there is a certain space between the top end of the inner shell 2 and the cover plate assembly 3, which can store more electrolyte and facilitate the flow of the electrolyte between the accommodation cavities 110, which is beneficial to extending the cycle life of the battery.

[0039] As some preferred embodiments, the cover plate assembly 3 includes a top cover 31, a pole 32, a lower plastic part 33 and a connecting piece 34. The lower plastic part 33 is fixedly arranged on the bottom surface of the top cover 31. The pole 32 is fixedly connected to the top cover 31 in an insulating manner. The connecting piece 34 is arranged on the side of the lower plastic part 33 away from the top cover 31. The center of the side of the connecting piece 34 facing the lower plastic part 33 has a convex part 341. The convex part 341 is welded to the pole 32. The surfaces of the connecting piece 34 on both sides of the convex part 341 respectively have welding areas 342 along the width direction of the top cover 31. The welding areas 342 are welded to the pole tabs 41 on the core package 4.

[0040] With the above technical solution, welding areas 342 are respectively arranged on the surfaces of the connecting piece 34 on both sides of the convex part 341 along the width direction of the top cover 31. The convex part 341 is welded to the pole 32, and the welding areas 342 are respectively welded to the pole tabs 41. This makes the welding points between the pole tabs 41 and the connecting piece 34 and the welding points between the connecting piece 34 and the pole 32 on the axis perpendicular to the width direction of the top cover 31, so as to realize the welding between the connecting piece 34 and the pole 32 and the welding between the connecting piece 34 and the pole tabs 41 in a straight line. The current can be conducted from the pole tabs 41 to the pole 32 through the connecting piece 34 along the shortest path. Such a design greatly reduces the path length in current transmission, avoids detours or complex current flow routes, and reduces the internal resistance. In addition, the shortening of the current path means that the energy transmission efficiency of the battery during operation is improved. Especially during fast charging or high-power output, the reduction of the internal resistance can effectively reduce the heating phenomenon and improve the safety and stability of the battery.

[0041] When welding the adapter plate 34 and the terminal post 32, the welding is carried out from the bottom surface of the adapter plate 34 to the terminal post 32 through penetration welding. Since the convex portion 341 protrudes from the top surface of the adapter plate 34, the laser welding needs to pass through the adapter plate 34 and the convex portion 341, and the thickness of the laser penetration is relatively large, resulting in too high welding power. Therefore, in this embodiment, a groove 343 corresponding to the position of the convex portion 341 is provided on the side away from the lower plastic part 33. With this setting, the welding penetration thickness can be reduced and the welding power can be lowered.

[0042] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A battery housing, comprising an outer shell (1), characterized in that: The housing (1) has a receiving space (11) with an open top. In the middle of the receiving space (11), an inner housing (2) is arranged along the length direction of the housing (1). Both ends of the inner housing (2) are fixedly connected to the inner wall of the receiving space (11). The inner housing (2) has a hollow channel (21) that penetrates the housing (1). The inner housing (2) divides the receiving space (11) into two accommodation cavities (110) for installing the core package (4) along the width direction of the housing (1).

2. The battery housing according to claim 1, wherein: There is a gap between the inner housing (2) and the bottom surface of the receiving space (11) for communicating the two accommodation cavities (110) with each other.

3. The battery housing according to claim 1, wherein: The width of the inner housing (2) is greater than 1 mm and less than 2 / 3 of the thickness of the housing (1).

4. The battery housing according to any one of claims 1 to 3, characterized in that: Inside the hollow channel (21), a plurality of partition plates (22) are vertically arranged at equal intervals along the length direction of the housing (1). The partition plates (22) are perpendicularly and fixedly connected to the inner wall of the hollow channel (21). A plurality of through holes (221) are arranged at equal intervals along the height direction of the partition plates (22).

5. A square lithium battery, characterized in that: It includes a cover plate assembly (3), a core package (4), and the battery housing according to any one of claims 1 to 4. At least one of the core packages (4) is arranged in the accommodation cavity (110). The cover plate assembly (3) is fixedly connected to the open end of the housing (1) and is electrically connected to the core package (4).

6. The square lithium battery according to claim 5, characterized in that, The top end of the inner housing (2) is flush with the top surface of the core package (4) or lower than the top surface of the core package (4).

7. The square lithium battery according to claim 6, wherein: The cover plate assembly (3) includes a top cover (31), a pole column (32), a lower plastic part (33), and a transition piece (34). The lower plastic part (33) is fixedly arranged on the bottom surface of the top cover (31). The pole column (32) is insulated and fixedly connected to the top cover (31). The transition piece (34) is arranged on the side of the lower plastic part (33) away from the top cover (31). A raised portion (341) is provided at the center of the side of the transition piece (34) facing the lower plastic part (33). The raised portion (341) is welded to the pole column (32). Welding areas (342) are respectively provided on the surfaces of the transition piece (34) on both sides of the raised portion (341) along the width direction of the top cover (31). The welding areas (342) are welded to the pole ears (41) on the core package (4).

8. The square lithium battery according to claim 7, wherein: A groove (343) corresponding to the position of the raised portion (341) is provided on the side of the transition piece (34) away from the lower plastic part (33).

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