Insulating case for secondary battery and secondary battery having the same
An insulating case for a secondary battery and a secondary battery having the same, the insulating case having opposing first and second portions. The first portion faces an electrode assembly of the secondary battery and has a first melting point. The second portion faces a cap assembly of the secondary battery and has a second melting point that is higher than the first melting point. The first melting point is approximately the contraction temperature of a separator of the electrode assembly.
1. An insulating case for a secondary battery that includes an electrode assembly, a can to house the electrode assembly, and a cap assembly to seal an opening of the can, the insulating case comprising:
a first portion that is a flat main body formed of a first material having a first melting point; and
a second portion that is at least one support contacting and extending from an edge of the main body, the at least one support being formed of a second material contacting the first material and having a second melting point that is higher than the first melting point.
2. The insulating case of claim 1 , wherein:
the first material is a low density polyethylene (LDPE) or a linear low density polyethylene (LLDPE); and
the second material is a polypropylene (PP) or a polyethylene terephthalate (PET).
3. The insulating case of claim 1 , wherein the first melting point is from about 90% to 110% of a contraction temperature of a separator of the electrode assembly.
4. The insulating case of claim 3 , wherein the first melting point of the first material is from about 95% to 105% of the contraction temperature of the separator.
5. The insulating case of claim 3 , wherein the first melting point is from about 100° C. to 145° C.
6. The insulating case of claim 4 , wherein the first melting point is from about 105° C. to 135° C.
7. A secondary battery comprising:
an electrode assembly comprising a first electrode plate, a second electrode plate, and a separator interposed between the first electrode plate and the second electrode plate, the separator having a contraction temperature;
a can to house the electrode assembly;
a cap assembly to seal an opening of the can; and
an insulating case disposed between the electrode assembly and the cap assembly, the insulating case comprising a first portion that faces the electrode assembly and is formed of a first material, and a second portion that faces the cap assembly and is formed of a second material contacting the first material, the second material being a polypropylene (PP) or a polyethylene terephthalate (PET),
wherein the first material has a first melting point that is substantially the same as the contraction temperature of the separator.
8. The secondary battery of claim 7 , wherein the first melting point is from about 95% to 105% of the contraction temperature of the separator.
9. The secondary battery of claim 7 , wherein the first melting point is from about 100° C. to 145° C.
10. The secondary battery of claim 8 , wherein the first melting point is from about 105° C. to 135° C.
11. The secondary battery of claim 7 , wherein:
the insulating case comprises a flat main body;
the first portion comprises a first surface of the main body; and
the second portion comprises an opposing second surface of the main body.
12. The secondary battery of claim 7 , wherein:
the first portion comprises a flat main body; and
the second portion comprises a support that extends from edge of the main body, toward the cap assembly.
13. The secondary battery of claim 7 , wherein the first portion and the second portion are formed of different materials.
14. The secondary battery of claim 13 , wherein the second portion has a second melting point that is higher than the first melting point.
15. The secondary battery of claim 14 , wherein the first material is a low density polyethylene (LDPE) or a linear low density polyethylene (LLDPE).
16. A. secondary battery comprising:
an electrode assembly comprising a first electrode plate, a second electrode plate, and a separator interposed between the first electrode plate and the second electrode plate, the separator having a contraction temperature;
a can to house the electrode assembly;
a cap assembly to seal an opening of the can; and
an insulating case disposed between the electrode assembly and the cap assembly, the insulating case comprising a first portion that faces the electrode assembly and is formed of a first material having a first melting point that is substantially the same as the contraction temperature of the separator, and a second portion that faces the cap assembly and is formed of a second material contacting the first material, the second material having a second melting point that is higher than the first melting point.
17. The secondary battery of claim 16 , wherein:
the insulating case comprises a flat main body;
the first portion comprises a first surface of the main body; and
the second portion comprises an opposing second surface of the main body.
18. The secondary battery of claim 16 , wherein:
the first portion comprises a flat main body; and
the second portion comprises a support that extends from an edge of the main body, toward the cap assembly.
19. The secondary battery of claim 16 , wherein the first material is a low density polyethylene (LDPE) or a linear low density polyethylene (LLDPE), and the second material is a polypropylene (PP) or a polyethylene terephthalate (PET).
20. The secondary battery of claim 16 , wherein the first melting point is from about 90% to 110% of the contraction temperature of the separator.
21. The secondary battery of claim 20 , wherein the first melting point is from about 95% to 105% of the contraction temperature of the separator.
22. The secondary battery of claim 20 , wherein the first melting point is from about 100° C. to 145° C.
23. The secondary battery of claim 21 , wherein the first melting point is from about 105° C. to 135° C.