Method for forming a pouch for a secondary battery
Provided is a structure of a pouch which may be used in a high-capacity battery having high capacity and high stiffness, wherein the pouch may include an upper housing module which includes a metallic base plate having a concave-shaped accommodation space and polymer layers formed on one surface or both surfaces of the base plate, and a lower pouch sheet which is combined with a lower surface of the upper housing module to seal the accommodation space.
1. A method for forming a pouch for a secondary battery, the method comprising:
forming an upper housing module with a base plate, the upper housing module having a concave-shaped accommodation space;
depositing a first reinforcing layer on an upper surface of the base plate;
depositing a second reinforcing layer on a lower surface of the base plate, the second reinforcing layer facing the accommodation space; and
depositing the upper housing module on a lower pouch sheet made of metal to seal the accommodation space,
wherein at least a portion of a metal surface of the lower pouch sheet is bonded directly to at least a portion of a non-metal outer surface of the second reinforcing layer.
2. The method of claim 1 , wherein the second reinforcing layer comprises at least two or more layers.
3. The method of claim 2 , wherein the second reinforcing layer comprises a first material layer that contacts the lower surface of the base plate, and a second material layer formed on the first material layer.
4. The method of claim 3 , wherein the first material layer is formed of a material having a higher melting point than the second material layer.
5. The method of claim 4 , wherein the first material layer is formed of a material having a 20° C. to 30° C. higher melting point than the second material layer.
6. The method of claim 1 , wherein the lower pouch sheet is formed of a material selected from the group consisting of an alloy of iron (Fe), carbon (C), chromium (Cr), and manganese (Mn), an alloy of Fe, C, Cr, and nickel (Ni), aluminum (Al), copper (Cu), an equivalent thereof, and a combination thereof.
7. The method of claim 1 , further comprising:
forming integrated lead tabs integrally in the upper housing module, wherein the integrated tabs are embedded in the upper housing module.
8. The method of claim 7 , further comprising:
placing an electrode assembly to be accommodated in the accommodation space, before the depositing the upper housing module on the lower pouch sheet,
wherein the integrated lead tabs are respectively connected to electrodes of the electrode assembly.
9. The method of claim 7 , wherein the integrated lead tabs are formed on a same side of the upper housing module.
10. The method of claim 7 , wherein the integrated lead tabs are formed on different sides of the upper housing module.
11. The method of claim 1 , wherein the base plate is formed of a material selected from the group consisting of Al, Fe, steel use stainless (SUS), high density plastic, and a combination thereof.
12. The method of claim 1 , wherein a total thickness of the first reinforcing layer and the second reinforcing layer is in a range of 80 μm to 200 μm.
13. The method of claim 1 , wherein a structure of the electrode assembly is a wound type structure, a stacked type structure, or a stacked/folded type structure.
14. The method of claim 7 , wherein the integrated lead tabs are integrally formed in the upper housing module to form a can-type structure thereby making the upper housing module sealed.
15. The method of claim 1 , the electrode assembly is classified as a jelly-roll type electrode assembly in which a plurality of long-sheet type cathodes and anodes are wound while separators are respectively disposed therebetween, or a stacked type electrode assembly in which a plurality of cathodes and anodes having a predetermined size are sequentially stacked while separators are respectively disposed therebetween.
16. The method of claim 1 , wherein the forming of the upper housing module and the forming of the integrated tab leads are done in one step.
17. The method of claim 1 , wherein the second reinforcing layer comprises one or more layers formed of a material selected from a group consisting of polyethylene (PE), polypropylene (PP), and a combination thereof.
18. The method of claim 1 , wherein the first reinforcing layer is formed of a material selected from a group consisting of cast polypropylene (CPP), urethane, polyethylene terephthalate (PET), polyimide (PI), Nylon, and a combination thereof.
19. The method of claim 1 , wherein the lower pouch sheet has a thickness in a range of 150 μm to 180 μm.
20. The method of claim 1 , wherein the base plate has a thickness in a range of 0.12 mm to 0.3 mm.
21. The method of claim 1 , wherein the upper housing module has a thickness in a range of 0.2 mm to 0.5 mm.