CN-116368667-B - Cylindrical secondary battery

Abstract

In order to solve the technical problem according to the present disclosure, there is provided a cylindrical secondary battery capable of preventing deformation of components during the manufacture or use thereof. To this end, the present disclosure provides a cylindrical secondary battery including a cylindrical can, an electrode assembly received in the cylindrical can, and a cap assembly for sealing the electrode assembly by covering the cylindrical can, wherein the cap assembly includes an upper cap portion, a lower cap portion disposed under the upper cap portion, and a safety vent disposed between the upper cap portion and the lower cap portion, and an elongation rate of the lower cap portion and an elongation rate of the safety vent are different from each other.

Inventors

• JIN DAKUI

Assignees

• 三星SDI株式会社

Dates

Publication Date

20260508

Application Date

20211111

Priority Date

20201214

Claims (7)

1. 1. A cylindrical secondary battery, the cylindrical secondary battery comprising: A cylindrical tank; an electrode assembly accommodated in the cylindrical can, and A cap assembly for sealing the electrode assembly by covering the cylindrical can, Wherein the cover assembly comprises an upper cover part, a lower cover part arranged below the upper cover part, and a safety vent arranged between the upper cover part and the lower cover part, and the extensibility of the lower cover part is higher than that of the safety vent, Wherein the safety vent includes a vent contact portion in contact with the upper cover portion, a vent inclined portion inclined downward from the vent contact portion, a vent hole bottom portion extending horizontally from the vent hole inclined portion, and a vent hole protruding portion protruding from the vent hole bottom portion and connected to the lower cover portion, and The lower cover part comprises a lower cover contact part, a lower cover inclined part, a lower cover bottom part, a through hole and a lower cover concave part, wherein the lower cover contact part is contacted with the safety vent hole through a connecting ring, the lower cover inclined part is inclined downwards from the lower cover contact part, the lower cover bottom part horizontally extends from the lower cover inclined part, the through hole penetrates through the lower cover bottom part, and the lower cover concave part is concave from the lower surface of the lower cover bottom part and is connected to the vent hole protruding part.
2. 2. The cylindrical secondary battery according to claim 1, wherein the safety vent and the lower cap part comprise aluminum or an aluminum alloy.
3. 3. The cylindrical secondary battery according to claim 1, wherein the safety vent comprises an aluminum-manganese-based alloy, and the lower cap part comprises pure aluminum having a purity of more than 99%.
4. 4. The cylindrical secondary battery according to claim 1, wherein the safety vent comprises 3003 series aluminum alloy or 3005 series aluminum alloy, and the lower cap portion comprises 1050 series aluminum alloy.
5. 5. The cylindrical secondary battery according to claim 1, wherein the safety vent and the lower cap part are connected to each other by laser welding.
6. 6. The cylindrical secondary battery according to claim 1, wherein the diameter of the vent hole protruding portion is 60% to 100% of the diameter of the vent hole bottom portion.
7. 7. The cylindrical secondary battery according to claim 1, wherein the lower cover concave portion is flat, and one of a positive electrode tab and a negative electrode tab is welded to the lower cover bottom portion.

Description

Cylindrical secondary battery Technical Field The present disclosure relates to a cylindrical secondary battery. Background Generally, a cylindrical secondary battery includes a cylindrical electrode assembly, a cylindrical can accommodating the electrode assembly and an electrolyte, and a cap assembly coupled to an upper opening of the can to seal the can and allow current generated from the electrode assembly to flow to an external device. The cap assembly may include a safety vent through which the internal gas is discharged when the internal pressure of the can is higher than a critical value. Since the internal pressure of the can is generally proportional to the temperature, there is a problem in that the safety vent is unexpectedly opened relatively rapidly when the secondary battery is placed in a high temperature environment. The above information disclosed in this background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art. Disclosure of Invention Technical problem The present disclosure provides a cylindrical secondary battery capable of delaying an opening time of a safety vent in a high temperature environment. Technical proposal The cylindrical secondary battery according to the present disclosure may include a cylindrical can, an electrode assembly received in the cylindrical can, and a cap assembly for sealing the electrode assembly by covering the cylindrical can, wherein the cap assembly includes an upper cap portion, a lower cap portion disposed under the upper cap portion, and a safety vent disposed between the upper cap portion and the lower cap portion, and an elongation rate of the lower cap portion and an elongation rate of the safety vent are different from each other. The lower cover part may have an elongation higher than that of the safety vent. The safety vent and the lower cover part may include aluminum or an aluminum alloy. The safety vent may include an aluminum-manganese (Al-Mn) based alloy, and the lower cover part may include pure aluminum having a purity of more than 99%. The safety vent may comprise 3003 series aluminum alloy or 3005 series aluminum alloy, and the lower cover portion may comprise 1050 series aluminum alloy. The safety vent and the lower cap part may be connected to each other by laser welding. The safety vent may include a vent contact portion contacting the upper cover portion, a vent inclined portion inclined downward from the vent contact portion, a vent bottom portion extending horizontally from the vent inclined portion, and a vent protruding portion protruding from the vent bottom portion and connected to the lower cover portion. The lower cover part may include a lower cover contact part contacting the safety vent through a connection ring, a lower cover inclined part inclined downward from the lower cover contact part, a lower cover bottom part horizontally extending from the lower cover inclined part, a through hole penetrating the lower cover bottom part, and a lower cover concave part concave from a lower surface of the lower cover bottom part and connected to the vent protruding part. Advantageous effects The present disclosure provides a cylindrical secondary battery capable of delaying an opening time of a safety vent in a high temperature environment. In some examples, since the extension rates of the safety vent and the lower cover part connected to each other are different, the opening time of the safety vent may be delayed in a high temperature environment. In some examples, the lower cover part has an elongation higher than that of the safety vent, and thus, when the internal pressure of the can increases in a high temperature environment, the lower cover part and the safety vent may separate (or rupture) after the lower cover part is sufficiently extended, thereby delaying the opening time of the safety vent in the high temperature environment. Drawings Fig. 1a, 1b and 1c are perspective, sectional and exploded perspective views illustrating an exemplary cylindrical secondary battery according to the present disclosure. Fig. 2 is a cross-sectional view illustrating an exemplary cap assembly in an exemplary cylindrical secondary battery according to the present disclosure. Fig. 3a and 3b are half sectional views illustrating the operation of an exemplary cap assembly in an exemplary cylindrical secondary battery according to the present disclosure. Fig. 4 is a half sectional view showing the operation of the cap assembly in the cylindrical secondary battery according to the comparative example. Fig. 5 is a graph showing a relationship between an internal pressure and displacement of an exemplary safety vent according to the present disclosure and a safety vent according to a comparative example. Detailed Description Examples of the present disclosure are provided to more fully explain the present disclosure to those skilled in