A fully-sealed lithium battery structure

Abstract

The application relates to the technical field of lithium batteries and discloses a fully-sealed lithium battery structure, which comprises a cover plate, a battery cell and a shell, the battery cell is arranged in the shell, the cover plate is connected to the upper end of the shell, an insulating gasket is arranged between the lower end of the battery cell and the shell, a cylindrical hole is arranged in the center of the battery cell, a first lug is connected to the inner wall of the battery cell, a second lug is connected to the outer wall of the battery cell, an anti-explosion notch is arranged in the bottom of the shell, a PTC short-circuit protection device is connected to the lower end of the shell, a false cover is connected to the lower end of the PTC short-circuit protection device, Z-shaped openings are arranged in the edge of the cover plate and the upper end of the shell, the two Z-shaped openings are matched with each other, and the connection part of the cover plate and the shell is sealed through laser welding. The application adopts the cooperative structure of the cylindrical hole in the center of the battery cell, the annular protruding insulating gasket and the anti-explosion notch in the bottom of the shell, forms a smooth air release channel, guarantees that high-pressure gas is discharged in time, and solves the safety hazards that the air release channel of a traditional lithium battery is prone to blockage and explosion.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, and in particular to a fully sealed lithium battery structure. Background Technology

[0002] Lithium batteries have been widely used in fields such as smart meters and monitoring equipment due to their wide operating temperature range. Their core structure usually includes a cover plate, battery cell, casing and various accessories. Some products are sealed through welding process and have explosion-proof structures in the casing to ensure safe use.

[0003] Traditional lithium batteries mostly use mechanical sealing or top laser / argon arc welding sealing. Mechanical sealing cannot meet the high sealing requirements under wide temperature conditions, while top welding requires fusion of the two end faces of the steel shell and the cover plate. The welding area is large and the energy required is high, which can easily damage the internal cells due to overheating. At the same time, its explosion-proof venting channel is prone to blockage. The core center hole is prone to collapse and the bottom pad is prone to sticking to the bottom of the shell, which prevents high-pressure gas from being discharged smoothly. Furthermore, the PTC short-circuit protection device can only be connected to the cover plate, which requires high assembly operation. The bottom explosion-proof weak point is also prone to being damaged by human intervention or occupying the effective space of the battery. The overall safety and space utilization of the structure need to be improved.

[0004] Based on this, a fully sealed lithium battery structure is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a fully sealed lithium battery structure in order to solve the above-mentioned problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A fully sealed lithium battery structure includes a cover plate, a battery cell, and a casing. The battery cell is disposed inside the casing. The cover plate is connected to the upper end of the casing. An insulating gasket is disposed between the lower end of the battery cell and the casing. A cylindrical hole is opened in the center of the battery cell. A first electrode tab is connected to the inner wall of the battery cell, and a second electrode tab is connected to the outer wall of the battery cell. Explosion-proof grooves are opened at the bottom of the casing. A PTC short-circuit protection device is connected to the lower end of the casing, and a dummy cover is connected to the lower end of the PTC short-circuit protection device.

[0007] Preferably, the cover plate has Z-shaped openings at its edge and the upper end of the housing, and the two Z-shaped openings fit together. The connection between the cover plate and the housing is sealed by laser welding.

[0008] Preferably, the first electrode and the second electrode are located on the same side of the battery cell.

[0009] Preferably, the lower end of the insulating pad is provided with an annular protrusion.

[0010] Preferably, the cover plate is assembled and riveted by sequentially assembling rivets, sealing rings, flat cover plates, gaskets and rivet rings.

[0011] Preferably, the lower end of the housing, the PTC short-circuit protection device, and the dummy cover are soldered together as one piece, and the diameter of the explosion-proof groove is smaller than the diameter of the inner opening of the PTC short-circuit protection device.

[0012] Preferably, the thickness of the insulating pad is the same as the thickness of the annular protrusion.

[0013] Preferably, the tab extends through the entire positive and negative electrode sheet of the battery cell, and the tab, after being wound, provides support for the central cylindrical hole of the battery cell.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This application replaces the traditional top welding by adopting a Z-shaped opening that fits the cover plate with the edge of the shell and a side laser welding structure. The weld is small and requires less energy, which reduces the heat of the cell during the welding process and avoids damage to the cell due to overheating. At the same time, the fitting Z-shaped opening improves the sealing performance of the battery and solves the problems of poor sealing effect and easy damage to the cell caused by traditional sealing process.

[0015] 2. This application adopts a collaborative structure of a cylindrical hole in the center of the cell, an insulating gasket with an annular protrusion, and explosion-proof markings on the bottom of the casing. The pair of tabs supporting the cylindrical hole in the center of the cell prevents it from collapsing and becoming blocked. The annular protrusion of the insulating gasket prevents the gasket from sticking to the bottom of the casing. Together with the explosion-proof markings, a smooth venting channel is formed, ensuring that high-pressure gas is discharged in a timely manner. This solves the safety hazards of easy blockage and explosion caused by the venting channel of traditional lithium batteries. Attached Figure Description

[0016] Figure 1 A schematic diagram of a half-section structure of a lithium battery provided according to an embodiment of the present invention is shown; Figure 2 An exploded view of a half-section of a lithium battery according to an embodiment of the present invention is shown. Figure 3 An exploded structural diagram of a cover plate provided according to an embodiment of the present invention is shown; Figure 4 An exploded view of the lower end of the housing provided according to an embodiment of the present invention is shown; Figure 5 A schematic diagram of the explosion-proof grooves provided according to an embodiment of the present invention is shown; Figure 6 The present invention provides an embodiment of the invention. Figure 1 Enlarged structural diagram at point A in the middle.

[0017] Legend: 1. Cover plate; 101. Rivet; 102. Sealing ring; 103. Flat cover plate; 104. Gasket; 105. Rivet ring; 2. Battery cell; 3. Tab 1; 4. Tab 2; 5. Insulating gasket; 501. Annular protrusion; 6. Housing; 601. Explosion-proof groove; 7. PTC short-circuit protection device; 8. False cover. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please see Figures 1-6 The present invention provides a technical solution: A fully sealed lithium battery structure includes a cover plate 1, a battery cell 2, and a housing 6. The cover plate 1 is made of 0.2~1mm SPCC flat steel plate. The battery cell 2 is disposed inside the housing 6. The cover plate 1 is connected to the upper end of the housing 6. An insulating gasket 5 is provided between the lower end of the battery cell 2 and the housing 6. A cylindrical hole is opened in the center of the battery cell 2, and the cylindrical hole runs through the upper and lower parts of the battery cell 2 to form a good venting channel. A first electrode tab 3 is connected to the inner wall of the battery cell 2, and a second electrode tab 4 is connected to the outer wall of the battery cell 2. An explosion-proof groove 601 is opened at the bottom of the housing 6. A PTC short-circuit protection device 7 is connected to the lower end of the housing 6. A dummy cover 8 is connected to the lower end of the PTC short-circuit protection device 7. The PTC short-circuit protection device 7 can achieve short-circuit protection and explosion-proof synergy.

[0020] Specifically, such as Figure 2 As shown, the edge of the cover plate 1 and the upper end of the housing 6 are provided with Z-shaped openings, and the two Z-shaped openings fit together. The Z-shaped opening is essentially a fitting step structure. The connection between the cover plate 1 and the housing 6 is sealed by laser welding. The weld seam formed by this welding method is small, the energy is low, and it is not easy to damage the battery cell 2.

[0021] Specifically, such as Figure 2 As shown, tab 3 and tab 4 are located on the same side of cell 2. Tab 3 has a width of 3~5mm and a thickness of 0.1mm. It is connected to the edge of the central cylindrical hole of cell 2, thereby supporting the central cylindrical hole of cell 2 to prevent it from collapsing.

[0022] Specifically, such as Figure 2As shown, the lower end of the insulating pad 5 is provided with an annular protrusion 501. The thickness of the insulating pad 5 is 0.1~0.3mm, and the middle opening is 2~3mm. The annular protrusion 501 can support the insulating pad 5, preventing the lower end of the battery cell 2 from sticking to the bottom of the housing 6, so that a cavity is formed at the connection between the battery cell 2 and the housing 6, ensuring smooth gas flow and allowing the high-pressure gas generated at high temperature to be discharged in time.

[0023] Specifically, such as Figure 3 As shown, the cover plate 1 is assembled and riveted by rivet 101, sealing ring 102, flat cover plate 103, gasket 104 and rivet ring 105 in sequence.

[0024] The sealing ring 102 significantly improves the reliability of waterproof and dustproof sealing. The mechanical riveting structure of rivets 101-rivet rings 105 enhances the mechanical strength of the cover plate against vibration and impact. Stamping and riveting avoids the high-temperature damage of traditional welding, reducing the risk of thermal impact on the battery cell. At the same time, this structure has mature technology, is easy to assemble, and is conducive to mass production and quality control, effectively balancing safety, durability and manufacturing cost.

[0025] Specifically, such as Figure 4 and Figure 5 As shown, the lower end of the housing 6, the PTC short-circuit protection device 7, and the dummy cover 8 are soldered together as one piece, and the diameter of the explosion-proof groove 601 is smaller than the diameter of the inner opening of the PTC short-circuit protection device 7.

[0026] By soldering the bottom of the casing 6, the PTC short-circuit protection device 7, and the dummy cover 8 into a single unit, the structural integration of short-circuit protection and explosion-proof pressure relief functions is achieved. The design of the explosion-proof groove 601 having a diameter smaller than the inner opening of the PTC short-circuit protection device 7 ensures that the pressure relief channel is unobstructed. This not only avoids the PTC short-circuit protection device 7 from obstructing gas discharge, but also forms a safety redundancy with the mechanical pressure relief of the explosion-proof groove 601 through the protective function of the PTC short-circuit protection device 7. This significantly improves the response reliability and overall safety of the battery under abnormal conditions. At the same time, the integrated structure simplifies the assembly process and enhances the bottom sealing.

[0027] Specifically, such as Figure 2 As shown, the thickness of the insulating pad 5 is the same as the thickness of the annular protrusion 501.

[0028] By setting the thickness of the insulating pad 5 to be the same as the thickness of its annular protrusion 501, it is ensured that the bottom of the battery cell receives uniform support to avoid stress concentration, and the constant gap between the insulating pad 5 and the bottom of the housing 6 is precisely maintained to prevent the venting channel from being blocked due to assembly errors or external deformation.

[0029] Specifically, such as Figure 2 As shown, tab 3 penetrates the entire positive and negative electrode plates of cell 2, and after being wound, tab 3 provides support for the central cylindrical hole of cell 2.

[0030] By designing tab 3 as an integral structure that runs through the positive and negative electrode plates of cell 2, and making it form a support for the central cylindrical hole after being wound up, the function of strengthening the current collection and venting channel structure is realized. This not only significantly reduces internal resistance and contact risk, but also effectively prevents channel collapse and blockage. While improving electrical performance and safety, it simplifies the structure and saves space.

[0031] In summary, the fully sealed lithium battery structure provided in this embodiment only requires welding the sides of the lithium battery after the cover plate 1 and the shell 6 are connected. By using side welding instead of top welding, the cell 2 is heated less, the welding energy required is small, and the fitting stepped structure improves the sealing effect at the connection.

[0032] The central cylindrical hole of the battery cell 2, the opening of the insulating gasket 5, and the "Y"-shaped explosion-proof groove 601 at the bottom of the casing 6 form a smooth venting channel to avoid blockage and explosion. The "Y"-shaped explosion-proof groove 601 design takes into account both protection and structural stability.

[0033] The flat cover and well-fitting step design effectively reduce space occupation, and the precise matching of component dimensions results in a compact structure.

[0034] The above description of the embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fully sealed lithium battery structure, comprising a cover plate (1), a battery cell (2), and a casing (6), characterized in that, The battery cell (2) is disposed inside the housing (6). The cover plate (1) is connected to the upper end of the housing (6). An insulating gasket (5) is provided between the lower end of the battery cell (2) and the housing (6). A cylindrical hole is opened in the center of the battery cell (2). A first electrode tab (3) is connected to the inner wall of the battery cell (2). A second electrode tab (4) is connected to the outer wall of the battery cell (2). The first electrode tab (3) penetrates the entire positive and negative electrode plates of the battery cell (2). After the first electrode tab (3) is wound, it forms a support for the cylindrical hole in the center of the battery cell (2). An explosion-proof groove (601) is opened at the bottom of the housing (6). A PTC short-circuit protection device (7) is connected to the lower end of the housing (6). A false cover (8) is connected to the lower end of the PTC short-circuit protection device (7). The lower end of the insulating pad (5) is provided with an annular protrusion (501). The lower end of the housing (6), the PTC short-circuit protection device (7) and the dummy cover (8) are soldered together, and the diameter of the explosion-proof groove (601) is smaller than the diameter of the inner opening of the PTC short-circuit protection device (7).

2. The fully sealed lithium battery structure according to claim 1, characterized in that, The cover plate (1) has Z-shaped openings at its edge and the upper end of the shell (6), and the two Z-shaped openings fit together. The connection between the cover plate (1) and the shell (6) is sealed by laser welding.

3. The fully sealed lithium battery structure according to claim 1, characterized in that, The first electrode (3) and the second electrode (4) are located on the same side of the battery cell (2).

4. The fully sealed lithium battery structure according to claim 1, characterized in that, The cover plate (1) is assembled and formed by stamping and riveting rivets (101), sealing rings (102), flat cover plates (103), gaskets (104) and rivet rings (105) in sequence.

5. The fully sealed lithium battery structure according to claim 1, characterized in that, The thickness of the insulating pad (5) is the same as the thickness of the annular protrusion (501).

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