Novel cover group sealing structure of lithium battery

Abstract

The utility model relates to the technical field of chemical battery structures, in particular to a novel cover group sealing structure of a lithium battery. The cover comprises an upper cover body and a lower cover body which are stacked together, the upper cover body is of a disc cap-shaped structure with the middle protruding outwards, the lower cover body is of a disc cap-shaped structure with the middle protruding outwards, and the protruding direction of the lower cover body is consistent with the protruding direction of the upper cover body. After the cover group sealing structure is connected with the battery core, the shell is assembled to form a complete lithium battery, and in the whole lithium battery structure body, as the convex direction of the lower cover is consistent with the convex direction of the upper cover, the size of the whole cover group sealing structure is reduced, the relative effective use space of the battery core is enlarged, and under the condition of the same battery size, the battery core is not damaged. According to the cover group sealing structure disclosed by the utility model, the effective output capacitance of the lithium battery is increased. And the upper cover and the lower cover are in surface contact with the PTC structural layer, so that the conductivity is safer and more reliable, and the battery is safer to use.

Description

Technical Field

[0001] This utility model relates to the technical field of chemical battery structure, and in particular to a novel cover sealing structure for lithium batteries. Background Technology

[0002] The sealing structure of a lithium battery includes an upper sealing cover, a positive temperature coefficient thermistor (PTC), a lower sealing cover, an aluminum foil, a sealing ring, and a housing. A pressure relief hole is located in the center of the lower cover. The aluminum foil adheres to the lower cover, covering the hole to prevent electrolyte leakage. Simultaneously, when the internal pressure of the battery is abnormal, the internal pressure breaks through the aluminum foil over the pressure relief hole and escapes through the vent hole on the upper cover, thus providing pressure relief. The PTC, also known as a "positive temperature coefficient thermistor," consists of three layers: upper and lower nickel-plated metal layers, and a middle polymer layer. When a large current flows through the battery or heats up, the middle polymer layer of the PTC expands, causing the upper and lower nickel-plated layers to separate, thus providing circuit safety protection. Under normal conditions, the polymer layer of the PTC is flat and uniform, and the expansion structure of the polymer is also evenly distributed. The upper end of the steel housing is waisted and then fastened to the outer sides of the upper cover, PTC layer, and lower cover, with a sealing ring at the fastening point. The existing lithium battery's sealing structure connects the battery cells, and the casing is assembled to form a complete lithium battery. However, the inward bulge of the upper and lower covers of the existing lithium battery, which is opposite to the outward bulge of the upper cover, reduces the effective volume of the lithium battery and prevents the battery capacity from being maximized. Utility Model Content

[0003] To address the aforementioned technical deficiencies, this utility model provides a novel cover sealing structure for lithium batteries.

[0004] To solve the above-mentioned technical problems, the technical solution used in this utility model is as follows: a novel cover sealing structure for a lithium battery, comprising an upper cover and a lower cover stacked together, wherein the upper cover is a disc-shaped cap structure with a central outward convexity, and the lower cover is a disc-shaped cap structure with a central outward convexity, wherein the outward convexity direction of the lower cover is consistent with the outward convexity direction of the upper cover.

[0005] Further: In the aforementioned novel lithium battery cover sealing structure, the upper cover includes a boss and a cap edge, and the lower cover includes a boss and a cap edge. An annular PTC structural layer is stacked between the upper and lower cap edges. A lower cover vent hole is provided in the center of the top of the boss of the lower cover. An explosion-proof film is provided on the inner side of the top of the boss of the lower cover, and the explosion-proof film completely covers the lower cover vent hole. An upper cover vent hole is provided in the center of the top of the boss of the upper cover; or, an upper cover vent hole is provided on the top edge of the boss of the upper cover; or, an upper cover vent hole is provided on the side wall of the boss of the upper cover. There are at least two evenly distributed upper cover vent holes. An annular sealing ring is provided at the outer edge of the stacked upper cover cap edge, lower cover cap edge, and PTC structural layer, and the annular sealing ring clamps the upper cover cap edge, lower cover cap edge, and outer edge of the PTC structural layer.

[0006] Compared with existing technologies, the novel lithium battery cover assembly sealing structure includes an upper cover and a lower cover stacked together. The upper cover is a disc-shaped cap structure with a central outward convexity, and the lower cover is a disc-shaped cap structure with a central outward convexity, with the outward convexity direction of the lower cover consistent with that of the upper cover. After the battery cell is connected to this cover assembly sealing structure and the outer casing is assembled, a complete lithium battery is formed. In the entire lithium battery structure, because the outward convexity direction of the lower cover is consistent with that of the upper cover, the volume of the entire cover assembly sealing structure is reduced, and the relatively effective usable space of the battery cell is increased. Under the same battery volume, the cover assembly sealing structure of this invention increases the effective output capacity of the lithium battery. In addition, the upper cover includes a boss and a cap edge, and the lower cover includes a boss and a cap edge. An annular PTC structure layer is stacked between the cap edges of the upper and lower covers, that is, the contact between the upper and lower covers and the PTC structure layer is surface contact, which makes the conductivity safer and more reliable, thereby making the battery safer to use. Attached Figure Description

[0007] Figure 1 This is a simplified longitudinal section diagram of the cover sealing structure of the novel lithium battery in Embodiment 1;

[0008] Figure 2 This is a simplified longitudinal section diagram of the cover sealing structure of the novel lithium battery in Embodiment 2;

[0009] Figure 3 This is a simplified longitudinal section diagram of the cover sealing structure of the novel lithium battery in Embodiment 3;

[0010] The components include: 1. Top cover, 2. Bottom cover, 3. PTC structural layer, 4. Bottom cover vent, 5. Explosion-proof membrane, 6. Top cover vent, and annular sealing ring. Detailed Implementation

[0011] The main objective of this invention is to improve the outward convex direction of the lower cover, making it consistent with the outward convex direction of the upper cover. This reduces the overall volume of the cover assembly sealing structure, thereby increasing the relatively effective usable space for the battery cell. With the same battery volume, the cover assembly sealing structure of this invention increases the effective output capacity of the lithium battery. The following detailed description of the invention, in conjunction with embodiments, is provided. However, the content mentioned in the embodiments is not intended to limit the scope of this invention.

[0012] Implementation method one: such as Figure 1 As shown, a novel lithium battery cover sealing structure includes an upper cover 1 and a lower cover 2 stacked together. The upper cover is a disc-shaped cap structure with a central outward convexity. The lower cover is also a disc-shaped cap structure with a central outward convexity, and the outward convexity direction of the lower cover is consistent with that of the upper cover. The upper cover includes a boss and a brim, and the lower cover also includes a boss and a brim. An annular PTC structural layer 3 is stacked between the brims of the upper cover 1 and the lower cover 2. A lower cover vent 4 is located at the center of the top of the boss of the lower cover. An explosion-proof film 5 is provided on the inner side of the top of the boss of the lower cover, completely covering the lower cover vent 4. An upper cover vent 6 is located at the center of the top of the boss of the upper cover. There are at least two evenly distributed upper cover vent 6. An annular sealing ring 7 is provided at the outer edge of the stacked upper cover brim, lower cover brim, and PTC structural layer, and the annular sealing ring 7 encloses the outer edge of the upper cover brim, lower cover brim, and PTC structural layer.

[0013] Implementation Method Two: (e.g.) Figure 2 As shown, compared with Embodiment 1, the top edge of the protrusion of the upper cover is provided with an upper cover vent 6.

[0014] Implementation Method 3: For example Figure 3 As shown, compared with Embodiment 1, the upper cover has an exhaust hole 6 on the side wall of the boss.

[0015] After the battery cells are connected to the cover assembly sealing structure obtained in embodiments one to three above, a complete lithium battery is formed by assembling the outer casing. In the entire lithium battery structure, since the outward convex direction of the lower cover is consistent with that of the upper cover, the volume of the entire cover assembly sealing structure is reduced, and the relatively effective usable space of the battery cells is increased. Under the same battery volume, the cover assembly sealing structure of the above embodiments increases the effective output capacity of the lithium battery. In addition, the upper cover includes a boss and a cap edge, and the lower cover includes a boss and a cap edge. An annular PTC structure layer is stacked between the cap edges of the upper and lower covers, that is, the contact between the upper and lower covers and the PTC structure layer is surface contact, which makes the conductivity safer and more reliable, thereby making the battery safer to use.

[0016] The above-described embodiments are merely preferred implementations of this utility model and are not intended to limit the scope of this utility model. Any obvious modifications and substitutions made without departing from the concept of this utility model shall fall within the protection scope of this utility model.

Claims

1. A novel cover sealing structure for a lithium battery, comprising an upper cover (1) and a lower cover (2) stacked together, wherein the upper cover is a disc-shaped cap structure with a central outward convexity, characterized in that: The lower cover is a disc-shaped cap structure that bulges outward in the middle, and the outward bulging direction of the lower cover is consistent with the outward bulging direction of the upper cover. The upper cover includes a boss and a brim, and the lower cover includes a boss and a brim. An annular PTC structure layer (3) is stacked between the brim of the upper cover (1) and the brim of the lower cover (2). An annular sealing ring (7) is provided at the edge of the upper cap, the edge of the lower cap, and the outer edge of the PTC structural layer. The annular sealing ring (7) encloses the edge of the upper cap, the edge of the lower cap, and the outer edge of the PTC structural layer.

2. The cover sealing structure of the novel lithium battery according to claim 1, characterized in that: The bottom cover has an exhaust hole (4) at the top center of the boss.

3. The cover sealing structure of the novel lithium battery according to claim 2, characterized in that: An explosion-proof film (5) is provided on the inner side of the top of the protrusion of the lower cover, and the explosion-proof film completely covers the exhaust hole (4) of the lower cover.

4. The cover sealing structure of the novel lithium battery according to claim 3, characterized in that: The top center of the raised platform of the top cover is provided with an exhaust hole (6).

5. The cover sealing structure of the novel lithium battery according to claim 3, characterized in that: The top edge of the raised platform of the top cover is provided with a vent hole (6).

6. The cover sealing structure of the novel lithium battery according to claim 3, characterized in that: The top cover has an exhaust vent (6) on the side wall of the boss.

7. The cover sealing structure of the novel lithium battery according to any one of claims 4-5, characterized in that: The upper cover has at least two evenly distributed exhaust holes (6).

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