A cylindrical battery shell and a cylindrical battery

Abstract

The utility model discloses a kind of shell of cylindrical battery and cylindrical battery.Casing includes single pass barrel, welding area, liquid injection hole and explosion-proof valve.Single pass barrel is composed of bottom cover and side wall, adopts aluminum metal integrated molding or welding seal;Welding area is located in bottom cover, thickness 0.2~0.4mm, 0.1~0.3mm is protruding to shell inside, periphery is equipped with 0.05~0.08mm deep's nick thinning structure, forms auxiliary explosion-proof design.Welding area can be long strip or sector, multiple welding area area accounts for bottom cover 20%~50%.Cylindrical battery includes the casing and battery cell, and battery cell tab is directly welded with welding area.The utility model cancels busbar, improves space utilization, reduces internal resistance, improves capacity and rate performance;Nick and explosion-proof valve cooperate to enhance security.

Description

Technical Field

[0001] This utility model belongs to the field of battery technology and relates to a cylindrical battery casing and a cylindrical battery. Background Technology

[0002] Cylindrical batteries are widely used in fields such as portable electronic devices. Traditional cylindrical battery designs typically leave a small uncoated area at the end of the coated electrode sheet for welding a single tab to achieve electrical connection between the cell and external circuitry. However, this design has significant limitations. Due to the small current-carrying area of ​​a single tab, the electron transport path from the positive to the negative electrode is longer, resulting in higher internal resistance and adversely affecting power density. Furthermore, in small cylindrical cells, the casing assembly occupies a large proportion of the volume, reducing the battery's energy density. These problems are particularly prominent in high-performance applications, such as electric vehicles requiring high-rate charging and discharging or fast-charging devices.

[0003] To improve the performance of cylindrical battery cells, the industry is increasingly inclined to manufacture larger batteries and adopt multi-tab or all-tab designs to increase current carrying capacity and reduce internal resistance. In multi-tab designs, the tabs of the positive and negative electrodes are welded to a busbar, which is then connected to the casing or external terminals. However, while this method improves electrical performance to some extent, it also introduces new challenges. First, busbars need to be welded to both ends of the positive and negative electrodes, which not only occupies valuable space inside the cell and reduces the energy density of a single cell, but also increases resistance due to the increased electron transport path introduced by the busbars. Second, the welding process for the busbars is complex, increasing production costs, and the stability of the welding quality is difficult to guarantee, potentially affecting the long-term reliability of the battery. Furthermore, the mechanical strength and current carrying capacity of the busbars are limited by their materials and size, making it difficult to meet the requirements of high-power scenarios.

[0004] To address the aforementioned issues, some existing technologies attempt to place the tabs of the positive and negative electrodes on the same end of the cell and separate the positive and negative busbars by an insulating sheet before welding. This design optimizes internal space utilization and shortens the electron transport path, thereby reducing internal resistance. However, this method still has limitations. For example, the width and current carrying capacity of the busbars are limited, making it difficult to meet the requirements of high-rate charging and discharging; the introduction of the insulating sheet and busbars increases design complexity and production costs; furthermore, the geometry and contact area limitations of the welding region may lead to unstable welding quality, causing fluctuations in electrical performance or safety hazards. These issues are particularly critical in the development of high-performance batteries, as batteries need to strike a balance between high energy density, high power density, and safety. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide a cylindrical battery casing and a cylindrical battery, which improves the space utilization and current carrying capacity of the casing by eliminating the structure of the busbar and optimizing the design of the welding area, thereby improving the capacity, rate performance and safety of the single cell.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A cylindrical battery casing, comprising:

[0008] A single-pass cylinder, comprising a bottom cover and side walls, wherein the bottom cover and side walls are integrally formed by aluminum extrusion or stamping, or are connected by welding and sealing.

[0009] A welding area is provided on the bottom cover. The welding area has a thinning design with a thickness of 0.2 to 0.4 mm, and the plane of the welding area protrudes into the shell by 0.1 to 0.3 mm.

[0010] An injection hole is provided on the bottom cover;

[0011] An explosion-proof valve is installed on the bottom cover;

[0012] The injection hole is located at the center of the bottom cover, and the welding area and explosion-proof valve are distributed around the injection hole. The welding area is provided with a scoring and thinning structure to form an auxiliary explosion-proof design. The depth of the scoring and thinning structure is 0.05 to 0.08 mm.

[0013] Furthermore, the diameter of the single-tube body is 30-60mm, the sidewall thickness is 0.3-0.5mm, and the bottom cover thickness is 0.5-0.8mm.

[0014] Furthermore, the welding area is elongated or fan-shaped.

[0015] Furthermore, when the welding area is elongated, its length is 15–25 mm and its width is 4–6 mm; when the welding area is fan-shaped, its radius is 10–20 mm and its central angle is 60°–120°.

[0016] Furthermore, the explosion-proof valve, in conjunction with the grooved and thinned structure of the welding area, controls the cell opening pressure to be between 0.3 and 1.0 MPa.

[0017] Furthermore, the scoring and thinning structure is linear or arc-shaped and distributed along the edge of the welding area.

[0018] Furthermore, there are multiple welding areas, evenly distributed on the bottom cover, and the total area of ​​the multiple welding areas accounts for 20%-50% of the area of ​​the bottom cover.

[0019] A cylindrical battery includes the aforementioned casing and a battery cell disposed within the casing, wherein the tabs of the battery cell are directly welded to the welding area.

[0020] The beneficial effects of this utility model are as follows:

[0021] 1. Significantly Improved Space Utilization: By eliminating the busbar structure, this invention frees up valuable internal space within the battery cell. Compared to the large volume occupied by the busbar in traditional designs, this design provides more space within the cell to accommodate active materials, thereby significantly increasing the capacity of a single cell. For example, in cylindrical batteries of the same diameter, this invention can increase the effective electrode material volume by 2% to 5%, making the battery design more compact. This is particularly suitable for applications requiring high energy density, such as electric vehicles and energy storage systems.

[0022] 2. Significantly Improved Electrical Performance: The cell tabs are directly welded to the casing welding area, eliminating the additional resistance from the busbars and significantly shortening the electron transport path. Test results show that the cylindrical battery of this invention has a DCR impedance of only 1.6–1.7 mΩ at 50% SOC, which is about 20%–27% lower than the 2.2 mΩ of the traditional design. Simultaneously, the 5C rate discharge capacity retention rate reaches 95%–97%, superior to the 92% of the traditional design. This low internal resistance and high rate performance improve the battery's charge / discharge efficiency and power density, making it perform excellently in high-power output scenarios (such as fast charging and instantaneous high-current discharge).

[0023] 3. Significantly Enhanced Safety: This invention features a 0.05–0.08 mm deep scoring and thinning structure around the welding area, which, in conjunction with the explosion-proof valve on the bottom cover, forms a multi-position explosion-proof design. When the internal pressure of the battery is abnormal, the scoring and thinning structure can break first, and the explosion-proof valve can release the pressure in time, effectively preventing the battery from exploding. The valve opening pressure is controlled between 0.3 and 1.0 MPa to adapt to the needs of different material systems and application scenarios. Compared with the traditional single explosion-proof valve design, this invention's composite explosion-proof mechanism improves the safety of the battery under extreme conditions such as overcharging, short circuits, or high temperatures.

[0024] 4. Effective Control of Production Costs: By simplifying the structure and eliminating the busbar and related insulating components, this invention reduces the number of parts, lowers material costs, and reduces assembly complexity. The welding area is directly located on the bottom cover of the housing, employing a thinning and protruding design to simplify the welding process and improve production efficiency. Compared to the complex busbar welding and bending processes in traditional designs, this invention has a more streamlined production process, making it suitable for large-scale automated production, and reducing overall manufacturing costs by approximately 10% to 15%.

[0025] Other advantages, objectives, and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination and study, or may be learned from practice of this invention. The objectives and other advantages of this invention can be realized and obtained through the following description. Attached Figure Description

[0026] To make the objectives, technical solutions, and advantages of this utility model clearer, the preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings, wherein:

[0027] Figure 1 This is a schematic diagram of the overall structure of the cylindrical battery casing in this utility model.

[0028] Figure 2 This is a schematic diagram of the bottom cover in Embodiment 1 of this utility model.

[0029] Figure 3 This is a schematic diagram of the bottom cover in Embodiment 2 of this utility model.

[0030] Reference numerals: 1-Injection hole; 2-Explosion-proof valve; 3-Welding area. Detailed Implementation

[0031] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this utility model. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0032] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the present invention. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0033] In the accompanying drawings of this utility model, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" 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 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, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this utility model. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0034] Example 1

[0035] A cylindrical battery casing, the structure of which is as follows: Figure 1 and Figure 2 As shown, the device includes a single-pass cylinder, a welding area 3, an electrolyte injection port 1, and an explosion-proof valve 2. The single-pass cylinder consists of a bottom cover and side walls, integrally formed from extruded aluminum, with a diameter of 46mm, a side wall thickness of 0.4mm, and a bottom cover thickness of 0.8mm. The welding area 3 is located on the bottom cover and features a thinning design, with a thickness of 0.3mm and a 0.2mm protrusion into the shell. The welding area 3 is elongated, 20mm long and 5mm wide. A straight-line serrated thinning structure with a depth of 0.05mm is provided around the welding area 3 to form an auxiliary explosion-proof design. The explosion-proof valve 2 works in conjunction with the serrated thinning structure to control the cell opening pressure between 0.3 and 1.0MPa. The electrolyte injection port 1 is located on the bottom cover and is used for electrolyte injection.

[0036] Example 2

[0037] A cylindrical battery casing, the structure of which is as follows: Figure 1 and Figure 3 As shown, the device includes a single-pass cylinder, a welding area 3, an electrolyte injection port 1, and an explosion-proof valve 2. The single-pass cylinder consists of a bottom cover and side walls, integrally formed from stamped aluminum metal, with a diameter of 46mm, a side wall thickness of 0.4mm, and a bottom cover thickness of 0.8mm. The welding area 3 is located on the bottom cover and features a thinning design, with a thickness of 0.3mm, and the welding area plane protrudes 0.3mm into the shell. The welding area 3 is fan-shaped with a radius of 15mm and a central angle of 45°. The periphery of the welding area 3 has an arc-shaped scoring thinning structure with a depth of 0.08mm, forming an auxiliary explosion-proof design. The explosion-proof valve 2 works in conjunction with the scoring thinning structure to control the cell opening pressure between 0.3 and 1.0MPa. The electrolyte injection port 1 is located on the bottom cover and is used for electrolyte injection.

[0038] Compare with Example 1

[0039] A traditional cylindrical battery casing uses a double-through cylindrical casing with a diameter of 46mm and a sidewall thickness of 0.4mm. The positive electrode cover is welded to the positive electrode tab of the battery cell via a busbar, and the negative electrode cover is welded to the negative electrode tab of the battery cell via a busbar. The positive and negative electrode covers are then welded to the casing after being bent via the busbar.

[0040] Performance testing

[0041] The cylindrical batteries of Example 1, Example 2 and Control Example 1 were subjected to electrical performance tests, including DCR impedance test and 5C rate discharge test. The results are shown in Table 1.

[0042] Table 1. Comparison of Electrical Performance Tests

[0043]

[0044] Test results show that the cylindrical battery using the casing of this invention outperforms the traditional casing design in terms of resistance and rate performance, verifying its advantages in electrical performance and space utilization.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of this technical solution, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A casing for a cylindrical battery, characterized in that, include: A single-pass cylinder, comprising a bottom cover and side walls, wherein the bottom cover and side walls are integrally formed by aluminum extrusion or stamping, or are connected by welding and sealing. A welding area is provided on the bottom cover. The welding area has a thinning design with a thickness of 0.2 to 0.4 mm, and the plane of the welding area protrudes into the shell by 0.1 to 0.3 mm. An injection hole is provided on the bottom cover; An explosion-proof valve is installed on the bottom cover; The injection hole is located at the center of the bottom cover, and the welding area and explosion-proof valve are distributed around the injection hole. The welding area is provided with a scoring and thinning structure to form an auxiliary explosion-proof design. The depth of the scoring and thinning structure is 0.05 to 0.08 mm.

2. The housing according to claim 1, characterized in that: The diameter of the single-tube body is 30-60mm, the side wall thickness is 0.3-0.5mm, and the bottom cover thickness is 0.5-0.8mm.

3. The housing according to claim 1, characterized in that: The welding area is elongated or fan-shaped.

4. The housing according to claim 3, characterized in that: When the welding area is elongated, its length is 15–25 mm and its width is 4–6 mm; when the welding area is fan-shaped, its radius is 10–20 mm and its central angle is 60°–120°.

5. The housing according to claim 1, characterized in that: The explosion-proof valve works in conjunction with the grooved and thinned structure of the welding area to control the cell opening pressure at 0.3 to 1.0 MPa.

6. The housing according to claim 1, characterized in that: The scoring and thinning structure is linear or arc-shaped and distributed along the edge of the welding area.

7. The housing according to claim 1, characterized in that: The welding area is multiple and evenly distributed on the bottom cover, and the total area of ​​the multiple welding areas accounts for 20%-50% of the area of ​​the bottom cover.

8. A cylindrical battery, characterized in that, The device includes a housing according to any one of claims 1 to 7, and a battery cell disposed within the housing, wherein the tabs of the battery cell are directly welded to the welding area.

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