KR-20260066964-A - SECONDARY BATTERY AND CASE FOR SECONDARY BATTERY

Abstract

The present disclosure provides a secondary battery and a case for the secondary battery. The secondary battery comprises an electrode assembly including a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode, a receiving portion having a receiving space formed to receive the electrode assembly, a lower case including a flange portion surrounding an open side of the receiving portion, and an upper cover connected to the flange portion of the lower case to seal an open side of the receiving portion. 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. At least one corner of the side wall portion is formed in a round shape connected by a curved surface having a first radius of curvature and a curved surface having a second radius of curvature, and the first radius of curvature may be larger than the second radius of curvature.

Inventors

• 이제완

Assignees

• 삼성에스디아이 주식회사

Dates

Publication Date

20260512

Application Date

20241105

Claims (20)

1. An electrode assembly comprising a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode; A lower case comprising a receiving portion having a receiving space formed to accommodate the electrode assembly, and a flange portion surrounding an open side of the receiving portion; and An upper cover connected to the flange portion of the lower case and sealing one side of the open portion of the receiving portion Includes, 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. At least one corner of the above-mentioned side wall is formed in a round shape in which a curved surface having a first radius of curvature and a curved surface having a second radius of curvature are connected, and A secondary battery in which the first radius of curvature is larger than the second radius of curvature.
2. In paragraph 1, A secondary battery in which at least one of the upper cover or the lower case comprises stainless steel (SUS).
3. In paragraph 1, A secondary battery in which the size of the first radius of curvature is set to increase as the thickness of the lower case decreases.
4. In paragraph 1, A secondary battery having a lower case thickness of 0.02 mm to 0.1 mm.
5. In paragraph 1, The thickness of the lower case is 0.02 mm to 0.04 mm, and A secondary battery having a first radius of curvature of 3.0 mm to 6.0 mm.
6. In paragraph 1, A secondary battery having a first radius of curvature of 2.0 mm to 6.0 mm.
7. In paragraph 1, A secondary battery having a depth of 0 mm or greater and 5.0 mm or less of the above-mentioned receiving portion.
8. In paragraph 1, The above-mentioned side wall portion comprises a first side connected to one end side of the bottom surface, a second side opposite to the first side, a third side connected to one end side of the bottom surface, and a fourth side opposite to the third side.
9. In paragraph 8, A secondary battery having a first electrode terminal electrically connected to the first electrode and a second electrode terminal electrically connected to the second electrode disposed on at least a portion of the first side.
10. In paragraph 8, A secondary battery, wherein each of the corners connecting the first side and the third side, the corner connecting the first side and the fourth side, the corner connecting the second side and the third side, and the corner connecting the second side and the fourth side is formed in a round shape in which a curved surface having the first radius of curvature and a curved surface having the second radius of curvature are connected.
11. In Paragraph 10, The curved surface having the first radius of curvature is connected to at least one of the first side or the second side, and A secondary battery in which the curved surface having the second radius of curvature is connected to at least one of the third side or the fourth side.
12. In Paragraph 10, Each of the corner connecting the bottom surface and the first side and the corner connecting the bottom surface and the second side is formed as a curved surface having a third radius of curvature, A secondary battery in which the corner connecting the bottom surface and the third side and the corner connecting the bottom surface and the fourth side are each formed as a curved surface having a fourth radius of curvature.
13. In Paragraph 12, A secondary battery in which the third radius of curvature and the fourth radius of curvature are the same.
14. In Paragraph 12, A secondary battery in which the size of the third radius of curvature and the size of the fourth radius of curvature are set to increase as the thickness of the lower case decreases.
15. In paragraph 1, A secondary battery in which at least a portion of the upper cover and the flange portion of the lower case are joined by laser welding.
16. In paragraph 1, At least a portion of the upper cover and the lower case has a laminated structure comprising a metal layer, an adhesive layer in contact with the metal layer, and a polymer layer in contact with the adhesive layer. A secondary battery in which at least a portion of the upper cover and the flange portion of the lower case are joined by thermal fusion of the polymer layer of the laminated structure.
17. A lower case comprising a receiving portion having a receiving space formed to accommodate an electrode assembly, and a flange portion surrounding an open side of the receiving portion; and An upper cover configured to be connected to the flange portion of the lower case and to seal one side of the open portion of the receiving portion Includes, 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. At least one corner of the above-mentioned side wall is formed in a round shape in which a curved surface having a first radius of curvature and a curved surface having a second radius of curvature are connected, and A case of a secondary battery in which the first radius of curvature is larger than the second radius of curvature.
18. In Paragraph 17, The above-mentioned side wall portion comprises a first side face connected to one end side of the bottom surface, a second side face opposite to the first side face, a third side face connected to one end side of the bottom surface, and a fourth side face opposite to the third side face, in a case of a secondary battery.
19. In Paragraph 18, A case for a secondary battery, wherein each of the corners connecting the first side and the third side, the corner connecting the first side and the fourth side, the corner connecting the second side and the third side, and the corner connecting the second side and the fourth side is formed in a round shape in which a curved surface having the first radius of curvature and a curved surface having the second radius of curvature are connected.
20. In Paragraph 19, The curved surface having the first radius of curvature is connected to at least one of the first side or the second side, and A case of a secondary battery, wherein the curved surface having the second radius of curvature is connected to at least one of the third side or the fourth side.

Description

Secondary Battery and Case for Secondary Battery The present disclosure relates to a secondary battery and a case for a secondary battery. Unlike primary batteries, which cannot be recharged, secondary batteries are batteries capable of both charging and discharging. Low-capacity secondary batteries are used in small portable electronic devices such as smartphones, feature phones, laptop computers, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources for motor drive systems and power storage batteries in hybrid and electric vehicles. Such secondary batteries include an electrode assembly consisting of a positive electrode and a negative electrode, a case housing the assembly, and electrode terminals connected to the electrode assembly. Since secondary batteries with high energy density (e.g., the amount of energy that can be stored per unit volume) can provide longer run times or driving ranges in portable devices or electric vehicles, energy density is one of the important factors determining the performance of secondary batteries. Accordingly, various technologies are being proposed to increase energy density by improving the structure of the secondary battery case. The information described above disclosed in the background technology of this invention is intended only to enhance understanding of the background of the present invention and may therefore include information that does not constitute prior art. The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. FIG. 1 is an exploded perspective view showing an example of a secondary battery according to some embodiments of the present disclosure. FIG. 2 is a drawing showing an example of a secondary battery according to some embodiments of the present disclosure. FIG. 3 is an exploded perspective view of a case of a secondary battery according to some embodiments of the present disclosure. FIG. 4 is a perspective view of a lower case according to some embodiments of the present disclosure, viewed from below. Figure 5 is a cross-sectional view of the lower case of Figure 4. Figure 6 is a diagram illustrating the difference in the size of the receiving space in which the electrode assembly is accommodated according to the change in the radius of curvature. Figure 7 is a diagram illustrating the occurrence of cracks due to the reduction of the radius of curvature. FIG. 8 is a table showing whether cracks occur according to a change in the first radius of curvature according to some embodiments of the present disclosure. FIG. 9 is an exploded perspective view of a pouch-type secondary battery according to some embodiments of the present disclosure. FIG. 10 is a cross-sectional view of a pouch-type secondary battery according to some embodiments of the present disclosure. Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe their invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. It should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application. Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments. Additionally, as used herein, “comprise, include” and/or “comprising, including” specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and/or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and/or groups. The statement that two subjects of comparison are 'identical' means that they are 'substantially identical'. Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean tha