Novel roll core exhaust structure

Abstract

The utility model discloses a novel roll core exhaust structure and belongs to the technical field of cylindrical battery roll cores. Comprising a coiled material, the coiled material comprises a material belt area and a tab area, and a plurality of regularly distributed exhaust holes are formed in the center of the upper position and the lower position of the tab area; according to the invention, the exhaust holes with the diameter of 0.04 mm are sequentially punched on the tab area before the positive and negative pole pieces are wound, and after the tab position is wound and kneaded, the small holes on the tab can be used as the internal exhaust channel of the roll core to communicate the internal and external environments of the roll core; gas generated in the roll core can be smoothly exhausted through the exhaust channel, the problems of overall volume expansion, structural damage and the like of the roll core caused by the gas generated in the roll core are avoided, no extra roll core structure needs to be added, the components of the battery are not influenced, the energy density of the original battery is not reduced, punching operation is synchronously performed in the original tab cutting process, and the production efficiency is improved. And the safety coefficient of the battery is improved.

Description

Technical Field

[0001] This utility model relates to a novel exhaust structure and belongs to the technical field of cylindrical battery cores. Background Technology

[0002] In the manufacturing process of cylindrical batteries, the flattening of the ends of the core is a critical step. Currently, there are two main technical approaches to the flattening process in the industry. One is to use a flattening mechanism to physically squeeze copper / aluminum foil material towards the center in a rotating manner, relying on mechanical pressure to achieve a flat state at the end of the core. The other is to use a "cut-stack-flatten" process, in which the tabs of the electrode sheet are first obliquely cut into multiple sheet-like structures, which are then wound into a stacked shape similar to a "vortex," and then flattened to shape them. Although the above-mentioned existing processes can achieve high-precision flatness at the end of the core, they cause a major core problem—a potential venting performance hazard. An overly flat end face causes the central hole of the cell to be completely blocked by the tabs, obstructing the gas venting channel. The gas generated inside the battery cannot be effectively released, significantly increasing the safety risk.

[0003] During the formation of lithium batteries, solvents in the electrolyte, such as EC and DEC, decompose on the surface of the negative electrode to generate gases such as CO, CO2, and H2. In addition, the positive electrode material may also generate gas, especially under high voltage. The oxidative decomposition of the electrolyte may produce O2, CO2, etc. The presence of moisture can cause LiPF6 to hydrolyze to generate HF, which in turn produces H2.

[0004] In summary, the core structure of a large cylindrical battery consists of positive and negative electrode sheets and a separator stacked sequentially and then wound together. After the top and bottom tabs are flattened, the inside of the core is sealed, lacking a clear and effective venting channel. This leads to gas accumulation inside the core, forming high-pressure "gas pockets" between the core layers. This gas accumulation causes the core to expand in volume, resulting in structural damage (bulging, separator damage). The expansion may cause battery deformation, and the increased internal pressure may lead to safety issues, affecting the quality of the SEI membrane and the battery's lifespan and performance. For example, patent CN115602932A discloses a full-tab core and its lithium-ion battery, which forms cavities for venting and leakage by indenting the two ends of the core body. However, this alters the structure of the core body, thereby compromising the overall energy density of the core and causing a decrease in the overall battery capacity. Therefore, developing a new core venting structure is essential. Utility Model Content

[0005] This utility model addresses the shortcomings of the existing technology by providing a novel core venting structure.

[0006] A novel core venting structure includes a roll material, which includes a strip area and an electrode area. Several regularly distributed venting holes are provided at the center of the upper and lower positions of the electrode area.

[0007] Furthermore, the distance between adjacent exhaust holes increases by two millimeters in sequence.

[0008] Furthermore, the distance between the first exhaust port and the side of the tab region ranges from 0.5 mm to 1 mm.

[0009] Furthermore, the distance between the first exhaust port and the second exhaust port is 1 mm.

[0010] Furthermore, all of the exhaust holes are circular.

[0011] Furthermore, the diameter of each exhaust port is 0.04 mm.

[0012] Furthermore, the electrode region includes a positive electrode region and a negative electrode region.

[0013] Furthermore, the vent hole is located on the upper end face of the core tab after the roll material is wound and flattened.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows: This invention uses 0.04mm diameter vent holes to be punched regularly on the tab area before the coil is wound. After the coil and flattening process is completed at the tab position, the small holes on the tab can serve as venting channels inside the coil core, connecting the internal and external environments of the coil core. When the coil core enters the formation process, the gas generated inside the coil core can be smoothly discharged through the venting channels, avoiding problems such as the overall volume expansion and structural damage of the coil core caused by gas generation inside the coil core. There is no need to add extra coil core structure, it does not affect the battery composition itself, and does not reduce the energy density of the original battery. The drilling operation is carried out simultaneously during the original tab cutting process, without adding coil core production steps or increasing production costs, thus improving the safety factor of the battery. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0016] Figure 2 This is a schematic diagram of the roll material portion of this utility model.

[0017] Figure 3 This is a left view of the structure of the core tab part of this utility model.

[0018] In the diagram, 1 is the roll material; 11 is the strip area; 12 is the tab area; 2 is the core; 21 is the tab; and 3 is the vent. Detailed Implementation

[0019] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0020] like Figures 1-3 As shown, a novel core venting structure includes a roll 1, which includes a strip area 11 and an electrode area 12. Several regularly distributed venting holes 3 are provided at the center of the upper and lower positions of the electrode area 12.

[0021] The distance between adjacent exhaust holes 3 increases by two millimeters each time.

[0022] The distance between the first exhaust port 3 and the side of the tab region 12 ranges from 0.5mm to 1mm.

[0023] The distance between the first exhaust hole 3 and the second exhaust hole 3 is 1 mm.

[0024] All of the exhaust holes 3 are circular.

[0025] The diameter of each of the exhaust holes 3 is 0.04 mm.

[0026] The electrode region 12 includes a positive electrode region and a negative electrode region.

[0027] The vent 3 is located on the upper end face of the tab 21 of the core 2 after the roll 1 is wound and flattened.

[0028] Before the roll material 1 is wound, a perforation operation is performed simultaneously during the cutting process of the original tab area 12. Specifically, vent holes 3 with a diameter of 0.04 mm are sequentially punched at the center positions of the tab area 12. The distance between the first vent hole 3 and the side position of the tab area 12 is 0.5 mm to 1 mm. The distance between the first vent hole 3 and the second vent hole 3 is 1 mm. The distance between the second vent hole 3 and the third vent hole 3 is 3 mm. The distance difference between any two adjacent vent holes 3 is 2 mm, and so on. After the roll material 1 is wound and flattened, the vent holes 3 on the upper end face of the tab 21 on the core 2 serve as venting channels to connect the internal and external environments of the core 2. When the core 2 enters the formation process, the gas generated inside the core 2 can be discharged through the vent holes 3 as venting channels, avoiding problems such as the overall volume expansion and structural damage of the core caused by gas generation inside the core 2.

[0029] Unlike other lithium battery venting solutions, this invention uses regularly punched vent holes 3 with a diameter of 0.04 mm on the tab area 12 before the positive and negative electrode sheets are wound. After the winding and flattening process at the tab 21 position, the vent holes 3 can serve as venting channels inside the core 2, connecting the internal and external environments of the core 2. When the core 2 enters the formation process, the gas generated inside the core 2 can be smoothly discharged through the vent holes 3. There is no need to add extra core 2 structure, it does not affect the battery composition itself, and does not reduce the energy density of the original battery. The punching operation is carried out simultaneously during the cutting process of the original tab area 12, without adding core 2 production steps or increasing production costs, but improving the safety factor of the battery.

[0030] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A novel core venting structure, comprising a roll (1), the roll (1) including a strip region (11) and an electrode tab region (12), characterized in that: Several regularly distributed exhaust holes (3) are provided at the center of the upper and lower positions of the electrode area (12).

2. The novel core venting structure according to claim 1, characterized in that: The distance between adjacent exhaust holes (3) increases by two millimeters.

3. The novel core venting structure according to claim 1, characterized in that: The distance between the first exhaust port (3) and the side of the tab region (12) is 0.5 mm to 1 mm.

4. The novel core venting structure according to claim 1, characterized in that: The distance between the first exhaust hole (3) and the second exhaust hole (3) is 1 mm.

5. The novel core venting structure according to claim 1, characterized in that: All the exhaust holes (3) are circular.

6. The novel core venting structure according to claim 1, characterized in that: The diameter of each of the exhaust holes (3) is 0.04 mm.

7. The novel core venting structure according to claim 1, characterized in that: The electrode region (12) includes a positive electrode region and a negative electrode region.

8. The novel core venting structure according to claim 1, characterized in that: The exhaust port (3) After the roll material (1) is wound and flattened, it is located on the upper end face of the tab (21) of the core (2).

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