Large cylindrical shell bottom center liquid injection battery

Abstract

The utility model discloses a center liquid injection battery with a large cylindrical shell bottom, which comprises an aluminum shell, a naked battery cell, a positive pole assembly and a negative pole assembly, the aluminum shell is arranged on the surface of the naked battery cell, the positive pole assembly and the negative pole assembly are respectively arranged at two ends of the naked battery cell, the aluminum shell is a positive pole, and the center of the aluminum shell is a positive pole post with a liquid injection hole and a positioning center hole convenient for battery cell liquid injection. The risk of uneven stress or inclination in the liquid injection process is reduced, and compared with an eccentric liquid injection mode, the method is simpler, and the process is more reliable; the positive current collector is welded with the wide area of the end face of the naked battery cell, so that the over-current area is greatly increased, the connection resistance is reduced, the high-current bearing capacity is high, and the high-power charge-discharge performance of the naked battery cell is realized; the height of the first boss is consistent with that of the external lead-out of the negative pole, and the negative pole assembly is compact in structure, small in size and high in energy density, so that the same-side and different-side aluminum row connection modes can be freely selected for parallel series connection of the large cylindrical shell bottom center liquid injection battery, and the battery module is flexible in forming mode and can be applied in multiple scenes.

Description

TECHNICAL FIELD

[0001] The utility model belongs to battery technical field, concretely relates to a big cylindrical shell bottom center liquid injection battery. BACKGROUND

[0002] Battery refers to cup, tank or other container or composite container's partial space that contains electrolyte solution and metal electrode to produce electric current, and can convert chemical energy into electric energy. It has positive and negative division.

[0003] Big cylindrical battery is considered to be the year of domestic scale in 2025 with its safety, cost effectiveness, high energy density and long cycle life. Electric aviation field is one of the emerging application fields of big cylindrical battery. With the continuous progress of technology and the reduction of cost, big cylindrical battery has broad application prospects in electric aviation field, and in the field of battery replacement and two-wheeled vehicles, due to the rapid development of take-out and other industries, higher requirements are put forward for the energy density, safety and cost of battery. Big cylindrical battery gradually penetrates into these fields and begins to occupy a certain market share,

[0004] At present, the number of single cylindrical battery system in small cylindrical power battery system is very large, which greatly increases the complexity of battery system software, and the production cost of the software level of the mechanism and management system is high. The probability of characteristic differentiation of a large number of battery cells is high under the condition of uneven working temperature environment. The energy density improvement space is limited. Although the energy density of big cylindrical battery has been improved, compared with other types of batteries (such as soft package battery), the energy density improvement space is relatively small. The production process is complex, and the number of assembled string and parallel of large capacity lithium battery is large, and the process is complex. Utility model content

[0005] The utility model aims at providing a big cylindrical shell bottom center liquid injection battery to solve the technical defects of complex production process and complex assembly string and parallel process of large capacity lithium battery of existing big cylindrical battery.

[0006] In order to achieve the above object, the utility model provides the following technical scheme:

[0007] A big cylindrical shell bottom center liquid injection battery, comprising an aluminum shell, a bare battery cell, a positive electrode assembly and a negative electrode assembly, the aluminum shell is arranged on the surface of the bare battery cell, the positive electrode assembly and the negative electrode assembly are arranged at two ends of the bare battery cell respectively, the aluminum shell comprises a shell body sleeved on the surface of the bare battery cell, one end of the shell body facing the negative electrode assembly is provided in an open manner, one end of the shell body close to the positive electrode current collector is provided with a first boss, the first boss and the shell body are an integral molding structure, the first boss is a positive electrode post, a liquid injection hole is formed in the shell body, the first boss is in a ring structure, and the liquid injection hole is located at the center of the first boss.

[0008] The positive electrode assembly comprises a positive electrode current collector welded with a positive electrode end face of the bare battery cell, the positive electrode current collector is connected with an inner wall surface of the shell, and a through groove corresponding to the liquid injection hole is formed in the positive electrode current collector.

[0009] As a further scheme of the utility model, the bare battery cell is wound by the positive electrode sheet, the negative electrode sheet and the diaphragm.

[0010] As a further scheme of the utility model, a second boss is arranged at the center of the surface of the positive electrode current collector, a through hole is arranged at the center of the second boss, and the positive electrode current collector is completely attached to and welded with the inner wall surface of the shell.

[0011] As a further scheme of the utility model, the positive electrode assembly further comprises a plastic fixing ring, the plastic fixing ring is arranged between the shell and the positive electrode current collector, the plastic fixing ring is attached to the positive electrode current collector, the plastic fixing ring and the shell are in clearance fit, and the plastic fixing ring is made of a PP modified material.

[0012] As a further scheme of the utility model, the negative electrode assembly comprises a negative electrode current collector welded with a negative electrode end face of the bare battery cell, a negative electrode pole is fixedly connected to a side of the negative electrode current collector away from the bare battery cell, a lower plastic is fixedly connected to an end of the bare battery cell close to the negative electrode current collector, the negative electrode current collector and the negative electrode pole are arranged in an inner cavity of the lower plastic, a negative electrode top cover is buckled to a side of the lower plastic away from the bare battery cell, the negative electrode top cover is welded with an open end of the shell to achieve sealing, an upper plastic is fixedly connected to the center of the surface of the negative electrode top cover, a negative electrode upper pressing plate is fixedly connected to the center of the surface of the upper plastic, the negative electrode pole has a stepped structure, and an end of the negative electrode pole away from the negative electrode current collector penetrates the centers of the lower plastic, the negative electrode top cover, the upper plastic and the negative electrode upper pressing plate in sequence.

[0013] As a further scheme of the utility model, through holes are arranged at the center of the surface of the negative electrode current collector and the periphery of the center.

[0014] As a further scheme of the utility model, the lower plastic and the upper plastic are made of an insulating, temperature-resistant, acid-resistant and alkali-resistant PP modified material, and the surface of the lower plastic is provided with a limiting groove matched with the negative electrode current collector.

[0015] As a further scheme of the utility model, a sealing ring is arranged at the penetration position of the negative electrode top cover and the upper plastic, an inner wall surface of the sealing ring is in contact with the surface of the negative electrode pole, and the sealing ring is made of a peroxide three-ethylenepropylene material.

[0016] As a further scheme of the utility model, an anti-explosion safety valve is arranged in the negative electrode top cover, and a protective sheet is attached to the outer layer of the anti-explosion safety valve.

[0017] As a preferred embodiment of this utility model, the negative current collector has a stepped bending structure, with the lower bending surface of the negative current collector welded to the negative terminal face of the bare battery cell; the upper bending surface of the negative current collector welded to the negative terminal; and the external lead-out height of the negative terminal and the positive terminal is the same.

[0018] Compared with existing technologies, the large cylindrical shell bottom center-filled battery provided by this utility model has the following beneficial effects:

[0019] 1. The large cylindrical shell bottom center liquid injection battery, through the setting of the aluminum shell, facilitates the positioning of the center hole for liquid injection of the cell, reduces the risk of uneven force or tilting during the liquid injection process, and is simpler and more reliable than other cylindrical eccentric liquid injection methods.

[0020] 2. This large cylindrical bottom center-filled battery greatly increases the current-carrying area and reduces the connection resistance by welding the positive electrode current collector to a wide area of ​​the bare cell end face, thus achieving high-power charge and discharge performance of the bare cell.

[0021] 3. This large cylindrical shell bottom center-filled battery achieves a compact structure with a small volume and high energy density by having the first protrusion and negative electrode post extended to the same height, and the plastic fixing ring and negative electrode top cover are tightly integrated. This allows the large cylindrical shell bottom center-filled battery to be connected in parallel or in series with aluminum busbars on the same or opposite sides, thus making the battery module forming method flexible and applicable to multiple scenarios. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only examples of embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model. Figure 1 ;

[0024] Figure 2 This is a schematic diagram of the structure of an embodiment of the present utility model. Figure 2 ;

[0025] Figure 3 This is an exploded view of the aluminum shell and bare battery cell in an embodiment of this utility model;

[0026] Figure 4 This is an exploded view of the structure of an embodiment of the present utility model. Figure 1 ;

[0027] Figure 2 This is an exploded view of the structure of an embodiment of the present utility model. Figures 1-3 .

[0028] Figure label:

[0029] 100. Aluminum shell; 110. Shell; 111. First boss; 120. Injection hole;

[0030] 200. Bare battery cells;

[0031] 300. Positive electrode assembly; 310. Positive electrode current collector; 311. Second boss; 320. Plastic retaining ring;

[0032] 400. Negative electrode assembly; 410. Negative electrode current collector; 420. Negative electrode post; 430. Lower plastic part; 440. Negative electrode top cover; 450. Upper plastic part; 460. Negative electrode upper pressure plate; 470. Sealing ring; 480. Protective sheet. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0034] In the description of the embodiments of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of 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. Therefore, they should not be construed as limitations on the embodiments of this utility model.

[0035] In the description of the embodiments of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; they can refer to the internal connection of two components; they can refer to a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of this utility model can be understood according to the specific circumstances.

[0036] See appendix Figure 2 As shown in the figure, an embodiment of the present invention provides a large cylindrical shell bottom center liquid-filled battery, including an aluminum shell 100, a bare cell 200, a positive electrode assembly 300, and a negative electrode assembly 400.

[0037] See Figure 3 , 3As shown, an aluminum shell 100 is disposed on the surface of the bare cell 200, and a positive electrode assembly 300 and a negative electrode assembly 400 are respectively disposed at both ends of the bare cell 200. The positive electrode assembly 300 is electrically connected to the aluminum shell 100.

[0038] See ​ , 4 As shown, the aluminum shell 100 includes a shell 110 sleeved on the surface of the bare battery cell 200. The end of the shell 110 facing the negative electrode assembly 400 is open. The end of the shell 110 near the positive electrode current collector 310 is provided with a first protrusion 111. The first protrusion 111 and the shell 110 are integrally formed by extrusion. The first protrusion 111 is the positive electrode post. The shell 110 is provided with a liquid injection hole 120. The first protrusion 111 has an annular structure, and the liquid injection hole 120 is located at the center of the first protrusion 111.

[0039] The positive electrode assembly 300 includes a positive electrode current collector 310 welded to the positive end face of the bare cell 200. The positive electrode current collector 310 is attached to the inner wall surface of the housing 110, and a through hole corresponding to the liquid injection hole 120 is provided on the positive electrode current collector 310.

[0040] In the above-mentioned cylindrical bottom center-filled battery, the first protrusion 111 is the positive electrode post, and the injection hole 120 is located at the center of the first protrusion 111, which facilitates the positioning of the cell injection center hole and reduces the risk of uneven force or tilting during the injection process. Compared with other cylindrical eccentric injection methods, it is simpler and the process is more reliable. Welding the positive current collector 310 to the wide area of ​​the bare cell 200 end face greatly increases the current-carrying area, reduces the connection resistance, and has a strong ability to withstand large currents, thus achieving high-power charge and discharge performance of the bare cell 200.

[0041] The bare cell 200 is made by winding a positive electrode, a negative electrode, and a separator.

[0042] A second protrusion 311 is provided at the center of the surface of the positive current collector 310, and a through hole is opened at the center of the second protrusion 311. The positive current collector 310 is completely attached to and fused with the inner wall surface of the housing 110.

[0043] To prevent the bare cell 200 from shaking inside the aluminum casing 100, in this embodiment, the positive electrode assembly 300 also includes a plastic retaining ring 320. The plastic retaining ring 320 is located between the casing 110 and the positive current collector 310. The plastic retaining ring 320 is attached to the positive current collector 310, and a clearance fit is used between the plastic retaining ring 320 and the casing 110. The plastic retaining ring 320 is made of modified PP material, which can withstand temperatures up to about 160°C and can stabilize the bare cell 200.

[0044] The negative electrode assembly 400 includes a negative electrode current collector 410 welded to the negative terminal face of the bare battery cell 200. A negative electrode post 420 is fixedly connected to the side of the negative electrode current collector 410 away from the bare battery cell 200. A lower plastic 430 is fixedly connected to the end of the bare battery cell 200 away from the positive electrode current collector 310. Both the negative electrode current collector 410 and the negative electrode post 420 are located in the inner cavity of the lower plastic 430. A negative electrode top cover 440 is fastened to the side of the lower plastic 430 away from the bare battery cell 200. The negative electrode top cover 440 is welded to the opening of the housing 110 to achieve a seal. An upper plastic 450 is fixedly connected to the center of the surface of the negative electrode top cover 440. A negative electrode upper pressure plate 460 is fixedly connected to the center of the surface of the upper plastic 450. The negative electrode post 420 adopts a stepped structure, and the end of the negative electrode post 420 away from the negative electrode current collector 410 passes through the center of the lower plastic 430, the negative electrode top cover 440, the upper plastic 450 and the negative electrode upper pressure plate 460 in sequence.

[0045] The negative electrode current collector 410 has a stepped bending structure. The lower bending surface of the negative electrode current collector 410 is welded to the negative terminal face of the bare cell 200; the upper bending surface of the negative electrode current collector 410 is welded to the negative electrode post 420; the first protrusion 111 and the negative electrode post 420 have the same height. The plastic fixing ring 320 and the negative electrode top cover 440 have a compact structure, small volume, and high energy density. This allows the large cylindrical shell bottom center liquid injection battery to be connected in series with the aluminum busbars on the same side or opposite side, which makes the battery module forming method flexible and applicable to multiple scenarios.

[0046] In order to facilitate electrolyte wetting and heat dissipation of the bare cell 200, in this embodiment, through holes are provided at the center and around the surface of the negative electrode current collector 410.

[0047] To facilitate the assembly and placement of the negative current collector 410, in this embodiment, both the lower plastic 430 and the upper plastic 450 are made of insulating, temperature-resistant, acid and alkali-resistant modified PP material, and the surface of the lower plastic 430 is provided with a limiting groove that is compatible with the negative current collector 410, so that the lower plastic 430 has a limiting and foolproof function.

[0048] In order to seal the bare cell 200, in this embodiment, a sealing ring 470 is provided at the penetration point of the negative electrode top cover 440 and the upper plastic 450. The inner wall surface of the sealing ring 470 is in contact with the surface of the negative electrode post 420. The sealing ring 470 is made of EPDM material.

[0049] In order to monitor the pressure changes inside the battery in real time, in this embodiment, an explosion-proof safety valve is installed inside the negative electrode top cover 440. Once the internal pressure exceeds the set threshold, the explosion-proof safety valve will automatically open to release the accumulated pressure and ensure the safety of the battery. A protective sheet 480 is attached to the surface of the explosion-proof safety valve to prevent foreign objects from damaging the explosion-proof safety valve.

[0050] The negative electrode current collector 410 adopts a stepped structure and runs through all other components of the negative electrode assembly 400. Through the riveting pressure between the negative electrode top cover 400 and the negative electrode post 420, the deformation of the sealing ring 470 reaches 15%-30%, thereby sealing the bare cell 200 and completing the forming of the negative electrode assembly 400.

[0051] The foregoing has shown and described the basic principles of the present invention. The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. The above embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Any modifications, equivalent substitutions, and improvements made within the scope of the present invention without departing from the scope of the present invention should be included within the protection scope of the present invention.

Claims

1. A large cylindrical shell bottom center liquid injection battery, comprising an aluminum shell (100), a bare cell (200), a positive electrode assembly (300), and a negative electrode assembly (400); The aluminum shell (100) is arranged on the surface of the bare cell (200), and the positive electrode assembly (300) and the negative electrode assembly (400) are arranged at two ends of the bare cell (200), respectively. characterized in that The aluminum shell (100) comprises a shell (110) arranged on the surface of the bare cell (200), one end of the shell (110) facing the negative electrode assembly (400) is arranged in an open manner, one end of the shell (110) close to the positive current collector (310) is provided with a first boss (111), the first boss (111) and the shell (110) are an integral structure, the first boss (111) is a positive electrode post, the shell (110) is provided with a liquid injection hole (120), the first boss (111) is an annular structure, and the liquid injection hole (120) is located at the center of the first boss (111). The positive electrode assembly (300) comprises a positive current collector (310) welded with a positive electrode end surface of the bare cell (200), the positive current collector (310) is connected with the inner wall surface of the shell (110), and the positive current collector (310) is provided with a through slot corresponding to the liquid injection hole (120).

2. A large cylindrical shell bottom center liquid injection battery according to claim 1, characterized in that: The bare cell (200) is wound by a positive electrode sheet, a negative electrode sheet, and a separator.

3. A large cylindrical shell bottom center liquid injection battery according to claim 2, characterized by: A second boss (311) is arranged on the surface of the positive current collector (310) at the center, a through hole is arranged at the center of the second boss (311), and the positive current collector (310) is completely attached and fused with the inner wall surface of the shell (110).

4. A large cylindrical shell bottom center liquid injection battery according to claim 3, characterized in that: The positive electrode assembly (300) further comprises a plastic fixing ring (320), the plastic fixing ring (320) is located between the shell (110) and the positive current collector (310), the plastic fixing ring (320) is attached with the positive current collector (310), the plastic fixing ring (320) is gap-fitted with the shell (110), and the plastic fixing ring (320) is made of a PP modified material.

5. A large cylindrical shell bottom center liquid injection battery as set forth in claim 4, wherein: The negative electrode assembly (400) comprises a negative electrode current collector (410) welded with a negative electrode end surface of a bare cell (200), a negative electrode post (420) provided on a side of the negative electrode current collector (410) away from the bare cell (200), a lower plastic (430) provided on an end of the bare cell (200) close to the negative electrode current collector (410), the negative electrode current collector (410) and the negative electrode post (420) being located in an inner cavity of the lower plastic (430), a negative electrode top cover (440) buckled on a side of the lower plastic (430) away from the bare cell (200), the negative electrode top cover (440) welded and sealed with an open end of a shell (110), an upper plastic (450) provided on a surface center of the negative electrode top cover (440), a negative electrode upper pressing plate (460) provided on a surface center of the upper plastic (450), the negative electrode post (420) adopting a stepped structure, and an end of the negative electrode post (420) away from the negative electrode current collector (410) penetrating the lower plastic (430), the negative electrode top cover (440), the upper plastic (450) and the center of the negative electrode upper pressing plate (460) in sequence.

6. A large cylindrical shell bottom center liquid injection battery as set forth in claim 5, wherein: A through hole is formed on a surface center of the negative electrode current collector (410) and a periphery of the surface center.

7. A large cylindrical shell bottom center liquid injection battery as set forth in claim 6, wherein: The lower plastic (430) and the upper plastic (450) both adopt an insulating, temperature-resistant, acid-resistant and alkali-resistant PP modified material, and a limiting groove compatible with the negative electrode current collector (410) is formed on a surface of the lower plastic (430).

8. A large cylindrical shell bottom center liquid injection battery as set forth in claim 7, wherein: A sealing ring (470) is provided at a penetration position of the negative electrode top cover (440) and the upper plastic (450), an inner wall surface of the sealing ring (470) is in contact with a surface of the negative electrode post (420), and the sealing ring (470) adopts a peroxide ternary ethylene-propylene material.

9. A large cylindrical shell bottom center liquid injection battery as set forth in claim 8, wherein: An explosion-proof safety valve is assembled in the negative electrode top cover (440), and a protective sheet (480) is attached to an outer layer of the explosion-proof safety valve.

10. A large cylindrical shell bottom center liquid injection battery as defined in claim 5, wherein: The negative electrode current collector (410) adopts a stepped and bent structure, a lower bent surface of the negative electrode current collector (410) is welded with the negative electrode end surface of the bare cell (200), and an upper bent surface of the negative electrode current collector (410) is welded with the negative electrode post (420), and the negative electrode post (420) has a same external leading height as a positive electrode post.

Images