CN-122000552-A - Secondary battery and case for the same

Abstract

The present disclosure provides a secondary battery and a case for the secondary battery. The secondary battery includes an electrode assembly, a lower case including a receiving part having a receiving space for receiving the electrode assembly, and a flange part surrounding an open side surface of the receiving part, and an upper cover connected to the flange part of the lower case and sealing the open side surface of the receiving part. The receiving portion of the lower case includes a bottom surface spaced apart from the flange portion, and a sidewall portion connecting the flange portion and the bottom surface to each other. At least one edge of the sidewall portion has a rounded shape including a curved surface having a first radius of curvature and a curved surface having a second radius of curvature joined to the curved surface having the first radius of curvature. The first radius of curvature is greater than the second radius of curvature.

Inventors

• LI JIWAN

Assignees

• 三星SDI株式会社

Dates

Publication Date

20260508

Application Date

20251105

Priority Date

20241105

Claims (20)

1. 1. A secondary battery, comprising: an electrode assembly including a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode; A lower case including a receiving part having a receiving space for receiving the electrode assembly, and a flange part surrounding an open side surface of the receiving part, and An upper cover coupled to the flange portion of the lower case and sealing the open side surface of the receiving portion, Wherein the receiving portion of the lower case includes a bottom surface spaced apart from the flange portion, a side wall portion connecting the flange portion and the bottom surface to each other, Wherein at least one edge of the side wall portion has a rounded shape including a curved surface having a first radius of curvature and a curved surface having a second radius of curvature, the curved surface having the second radius of curvature being joined to the curved surface having the first radius of curvature, and Wherein the first radius of curvature is greater than the second radius of curvature.
2. 2. The secondary battery according to claim 1, wherein at least one of the upper cover and the lower case comprises stainless steel (SUS).
3. 3. The secondary battery according to claim 1, wherein a size of the first radius of curvature increases as a thickness of the lower case decreases.
4. 4. The secondary battery according to claim 1, wherein a thickness of the lower case is in a range of 0.02 mm to 0.1 mm.
5. 5. The secondary battery according to claim 1, wherein a thickness of the lower case is in a range of 0.02 mm to 0.04 mm, and a size of the first radius of curvature is in a range of 3.0 mm to 6.0 mm.
6. 6. The secondary battery according to claim 1, wherein a size of the first radius of curvature is in a range of 2.0 mm to 6.0 mm.
7. 7. The secondary battery according to claim 1, wherein a depth of the receiving portion is greater than 0mm and equal to or less than 5.0 mm.
8. 8. The secondary battery according to claim 1, wherein the side wall portion includes: A first side surface connected to one short side of the bottom surface; a second side surface facing the first side surface; A third side surface connected to one long side of the bottom surface, and A fourth side surface facing the third side surface.
9. 9. The secondary battery according to claim 8, wherein a first electrode terminal electrically connected to the first electrode and a second electrode terminal electrically connected to the second electrode are located on at least a portion of the first side surface.
10. 10. The secondary battery according to claim 8, wherein each of an edge at which the first side surface and the third side surface are bonded to each other, an edge at which the first side surface and the fourth side surface are bonded to each other, an edge at which the second side surface and the third side surface are bonded to each other, and an edge at which the second side surface and the fourth side surface are bonded to each other has a rounded shape in which the curved surface having the first radius of curvature and the curved surface having the second radius of curvature are bonded to each other.
11. 11. The secondary battery according to claim 10, wherein the curved surface having the first radius of curvature is connected to at least one of the first side surface and the second side surface, and Wherein the curved surface having the second radius of curvature is connected to at least one of the third side surface and the fourth side surface.
12. 12. The secondary battery according to claim 10, wherein each of the edge where the bottom surface and the first side surface are bonded to each other and the edge where the bottom surface and the second side surface are bonded to each other has a curved surface having a third radius of curvature, Wherein each of an edge where the bottom surface and the third side surface are bonded to each other and an edge where the bottom surface and the fourth side surface are bonded to each other has a curved surface having a fourth radius of curvature.
13. 13. The secondary battery according to claim 12, wherein the third radius of curvature is the same as the fourth radius of curvature.
14. 14. The secondary battery according to claim 12, wherein a size of the third radius of curvature and a size of the fourth radius of curvature increase as a thickness of the lower case decreases.
15. 15. The secondary battery according to claim 1, wherein at least a portion of the upper cover is joined to the flange portion of the lower case by laser welding.
16. 16. The secondary battery according to claim 1, wherein each of at least a portion of the upper cover and the flange portion of the lower case has a stacked structure including: A metal layer; An adhesive layer in contact with the metal layer, and A polymer layer in contact with the adhesive layer, and Wherein the at least a portion of the upper cover is joined to the flange portion of the lower housing by heat welding the polymer layer in the at least a portion of the upper cover and the polymer layer in the flange portion of the lower housing to each other.
17. 17. A case for a secondary battery, comprising: A lower case including a receiving part having a receiving space for receiving the electrode assembly, a flange part surrounding an open side surface of the receiving part, and An upper cover coupled to the flange portion of the lower case and sealing the open side surface of the receiving portion, Wherein the receiving portion of the lower case includes a bottom surface spaced apart from the flange portion, and a side wall portion connecting the flange portion and the bottom surface to each other, Wherein at least one edge of the side wall portion has a rounded shape including a curved surface having a first radius of curvature and a curved surface having a second radius of curvature, the curved surface having the second radius of curvature being joined to the curved surface having the first radius of curvature, and Wherein the first radius of curvature is greater than the second radius of curvature.
18. 18. The case for a secondary battery according to claim 17, wherein the side wall portion includes: A first side surface connected to one short side of the bottom surface; a second side surface facing the first side surface; A third side surface connected to one long side of the bottom surface, and A fourth side surface facing the third side surface.
19. 19. The case for a secondary battery according to claim 18, wherein each of an edge where the first side surface and the third side surface are bonded to each other, an edge where the first side surface and the fourth side surface are bonded to each other, an edge where the second side surface and the third side surface are bonded to each other, and an edge where the second side surface and the fourth side surface are bonded to each other has a rounded shape in which the curved surface having the first radius of curvature and the curved surface having the second radius of curvature are bonded to each other.
20. 20. The case for a secondary battery according to claim 19, wherein the curved surface having the first radius of curvature is connected to at least one of the first side surface and the second side surface, and Wherein the curved surface having the second radius of curvature is connected to at least one of the third side surface and the fourth side surface.

Description

Secondary battery and case for the same Technical Field Aspects of embodiments of the present disclosure relate to a secondary battery and a case for the secondary battery. Background Unlike primary batteries that are not designed to be (re) charged, secondary (or rechargeable) batteries are batteries that are designed to be discharged and re-charged. Low-capacity secondary batteries are used in portable small-sized electronic devices such as smart phones, function phones, notebook computers, digital still cameras, and video cameras, while high-capacity secondary batteries are widely used as power sources for driving motors in hybrid vehicles and electric vehicles and as batteries for storing electric power (e.g., electric power storage at home and/or utility scale). The secondary battery generally includes an electrode assembly including a positive electrode and a negative electrode, a case accommodating the same, and an electrode terminal connected to the electrode assembly. Secondary batteries having a high energy density (e.g., an amount of storable energy per unit volume) may provide longer running time or longer mileage for portable devices or electric vehicles, and the energy density of the secondary batteries may be one of the key factors in determining the performance of the secondary batteries. Accordingly, various techniques for increasing energy density (e.g., such as by improving the structure of a case in a secondary battery) may be required. The above information disclosed in this background section is for enhancement of understanding of the background of the disclosure and, therefore, may contain information that does not form a related (or prior) art. Disclosure of Invention Embodiments of the present disclosure may be directed to a secondary battery and a case for the secondary battery. These and other aspects and features of the present disclosure will be described in, or will be apparent from, the following description of the embodiments of the present disclosure. According to one or more embodiments of the present disclosure, a secondary battery includes an electrode assembly including a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode, a lower case including a receiving part having a receiving space for receiving the electrode assembly, and a flange part surrounding an open side surface of the receiving part, and an upper cover coupled to the flange part of the lower case and sealing the open side surface of the receiving part. The receiving portion of the lower case includes a bottom surface spaced apart from the flange portion, and a sidewall portion connecting the flange portion and the bottom surface to each other. At least one edge of the sidewall portion has a rounded shape including a curved surface having a first radius of curvature and a curved surface having a second radius of curvature joined to the curved surface having the first radius of curvature. The first radius of curvature is greater than the second radius of curvature. In an embodiment, at least one of the upper cover and the lower case includes stainless steel (SUS). In an embodiment, the first radius of curvature may increase in size as the thickness of the lower housing decreases. In an embodiment, the thickness of the lower housing may be in the range of 0.02 mm to 0.1 mm. In an embodiment, the thickness of the lower housing may be in the range of 0.02 mm to 0.04 mm and the size of the first radius of curvature may be in the range of 3.0 mm to 6.0 mm. In an embodiment, the first radius of curvature may have a size in the range of 2.0 mm to 6.0 mm. In an embodiment, the depth of the receiving portion may be greater than 0 mm and equal to or less than 5.0 mm. In one embodiment, the sidewall portion may include a first side surface connected to one short side of the bottom surface, a second side surface facing the first side surface, a third side surface connected to one long side of the bottom surface, and a fourth side surface facing the third side surface. In an embodiment, a first electrode terminal electrically connected to the first electrode and a second electrode terminal electrically connected to the second electrode may be located on at least a portion of the first side surface. In an embodiment, each of the edge where the first side surface and the third side surface are bonded to each other, the edge where the first side surface and the fourth side surface are bonded to each other, the edge where the second side surface and the third side surface are bonded to each other, and the edge where the second side surface and the fourth side surface are bonded to each other may have a rounded shape in which a curved surface having a first radius of curvature and a curved surface having a second radius of curvature are bonded to each other. In an embodiment, a curved surface having a first radius of curvature may be connected to at least one of