CROSS-REFERENCE TO RELATED APPLICATION

The present application is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/KR2019/000856, filed Jan. 21, 2019, which claims the benefit of the priority of Korean Patent Application No. 10-2018-0028018, filed on Mar. 9, 2018, both of the disclosures of which are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a method for manufacturing a secondary battery and a pouch for the secondary battery.

BACKGROUND ART

Secondary batteries are rechargeable unlike primarily batteries, and also, the possibility of compact size and high capacity is high. Thus, recently, many studies on rechargeable batteries are being carried out. As technology development and demands for mobile devices increase, the demands for rechargeable batteries as energy sources are rapidly increasing.

Rechargeable batteries are classified into coin type batteries, cylindrical type batteries, prismatic type batteries, and pouch type batteries according to a shape of a battery case. In such a secondary battery, an electrode assembly mounted in a battery case is a chargeable and dischargeable power generating device having a structure in which an electrode and a separator are stacked.

The electrode assembly may be approximately classified into a jelly-roll type electrode assembly in which a separator is interposed between a positive electrode and a negative electrode, each of which is provided as the form of a sheet coated with an active material, and then, the positive electrode, the separator, and the negative electrode are wound, a stacked type electrode assembly in which a plurality of positive and negative electrodes with a separator therebetween are sequentially stacked, and a stack/folding type electrode assembly in which stacked type unit cells are wound together with a separation film having a long length.

Recently, the pouch-type battery in which a stack/folding type electrode assembly is built in a pouch-type battery case provided as an aluminum lamination sheet is attracting much attention due to its low manufacturing cost, small weight, easy shape deformation, and the like, and thus, its usage is gradually increasing.

However, when the pouch accommodating the electrode assembly is folded to manufacture the secondary battery, a wrinkle having a bat-ear shape may occur on the folded portion.

DISCLOSURE OF THE INVENTION

Technical Problem

One aspect of the present invention is to provide a method for manufacturing a secondary battery, through which capacity increases, and an occurrence of a winkle when a battery case is folded is prevented or significantly reduced, and a pouch for the secondary battery.

Technical Solution

A method for manufacturing a secondary battery according to an embodiment of the present invention includes a forming step of pressing a pouch sheet by using a press die so that left and right accommodation grooves, which are bilaterally symmetrical to each other and are opened upward, and a bridge connecting the left and right accommodation grooves to each other are formed in the pouch sheet, wherein the bridge protrudes upward with respect to bottom surfaces of the left and right accommodation grooves, and a curved portion having a rounded shape is formed on an upper end of the bridge, a seating step of seating an electrode assembly in one of the left and right accommodation grooves, and a folding step of folding the pouch sheet so that the left and right accommodation grooves face each other.

A pouch for a secondary battery according to an embodiment of the present invention includes a pouch sheet, wherein in an unfolded form, the pouch sheet includes left and right accommodation grooves for accommodating an electrode assembly when the pouch sheet is in a folded form and which are bilaterally symmetrical to each other and are opened upward and a bridge connecting the left and right accommodation grooves to each other, wherein the bridge protrudes upward with respect to bottom surfaces of the left and right accommodation grooves, and a curved portion having a rounded shape is formed on an upper end of the bridge.

Advantageous Effects

According to the present invention, the battery case may be formed with the structure that is optimized to accommodate the electrode assembly and then be folded to increase in capacity and prevent the wrinkle such as the bat-ear shape from occurring or significantly reduce the occurrence of the wrinkle when the battery case is folded.

