Method for manufacturing secondary battery and pouch for secondary battery

Patent metadata

Field	Value
Publication number	US-11283139-B2
Application number	US-201916763120-A
Country	US
Kind code	B2
Filing date	Jan 21, 2019
Priority date	Mar 9, 2018
Publication date	Mar 22, 2022
Grant date	Mar 22, 2022

Abstract

A method for manufacturing a secondary battery 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.

First claim

The invention claimed is:

1. A method for manufacturing a secondary battery, the method comprising:
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,
wherein, in the forming step, a first bending part having a shape in which outer side surfaces of the left and right accommodation grooves are respectively bent downward with respect to outer circumferential surfaces of the pouch sheet has a first curved surface having a rounded shape,
a second bending part having a shape in which the outer side surfaces of the left and right accommodation grooves are respectively bent upward with respect to the bottom surfaces of the left and right accommodation grooves has a second curved surface having a rounded shape, and
the pouch sheet is formed so that a width of each of inflection surfaces of the outer side surfaces that are formed between the first curved surface and the second curved surface is 0.5 mm or less,
wherein, in the forming step, the pouch sheet is formed so that each of the inflection surfaces has a planar shape, and
each of an angle between each of the outer circumferential surfaces and each of the inflection surfaces of the pouch sheet and an angle between each of the inflection surfaces and each of the bottom surfaces of the left and right accommodation grooves is 93° to 98°.

2. The method of claim 1 , wherein, in the forming step, the pouch sheet is formed so that the bottom surfaces of the left and right accommodation grooves are inclined to be bilaterally symmetrical to each other,
wherein the bottom surfaces of the left and right accommodation grooves have inclinations decreasing in a direction that is away from the bridge.

3. The method of claim 2 , wherein, in the forming step, the inclination of each of the bottom surfaces of the left and right accommodation grooves decreases at an angle of 1.5° to 3°.

4. The method of claim 1 , wherein, in the forming step, the pouch sheet is formed so that the upper end of the bridge has a semicircular shape.

5. The method of claim 1 , wherein, in the forming step, when a length along the pouch sheet between a portion, which contacts a lower edge of the electrode assembly adjacent to the bridge, and the bridge is d 1 , a length along the pouch sheet between a portion, which contacts an upper edge of the electrode assembly adjacent to the bridge, and the bridge is d 2 , a length along the pouch sheet of the bridge is d 3 , and a height of the electrode assembly seated on the pouch sheet is h, the pouch sheet is formed to satisfy following conditional expression: h≤d 1 +d 2 +d 3 .

6. The method of claim 5 , wherein, in the forming step, the pouch sheet is formed so that the bridge has a width of 4 mm or less.

7. The method of claim 6 , wherein, in the forming step, the pouch sheet is formed so that the bridge has a width of 1 mm to 2 mm.

8. The method of claim 7 , wherein, in the forming step, when a height of the electrode assembly seated on the pouch sheet is h, and a protruding height of the bridge with respect to the bottom surfaces of the pouch sheet is a, the pouch sheet is formed to satisfy following conditional expression: h/2≥a.

9. The method of claim 7 , wherein the bridge has a width defined by a width of a protrusion protruding between the left and right accommodation grooves, and
end points of the width of the protrusion are defined by inflection points between bending parts adjacent the bottom surfaces of the left and right accommodation grooves and side surfaces of the protrusion.

10. A pouch for a secondary battery, the pouch comprising:
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,
wherein a first bending part having a shape in which outer side surfaces of the left and right accommodation grooves are respectively bent downward with respect to outer circumferential surfaces of the pouch sheet is formed with a first curved surface having a rounded shape,
a second bending part having a shape in which the outer side surfaces of the left and right accommodation grooves are respectively bent upward with respect to the bottom surfaces of the left and right accommodation grooves has a second curved surface having a rounded shape, and
a width of each of inflection surfaces of the outer side surfaces that are formed between the first curved surface and the second curved surface is 0.5 mm or less,
each of the inflection surfaces has a planar shape, and
each of an angle between each of the outer circumferential surfaces and each of the inflection surfaces of the pouch sheet and an angle between each of the inflection surfaces and each of the bottom surfaces of the left and right accommodation grooves is 93° to 98°.

11. The pouch of claim 10 , wherein, in the pouch sheet, in its unfolded form, the bridge has a width of 1 mm to 2 mm.

12. A secondary battery comprising:
a pouch of claim 10 ; and
an electrode assembly accommodated in the left and right accommodation grooves with the pouch sheet in a folded form so that the left and right accommodation grooves face each other.

13. The pouch of claim 10 , wherein:
when a length along the pouch sheet between a portion, which is configured to contact a lower edge of the electrode assembly adjacent to the bridge, and the bridge is d 1 , a length along the pouch sheet between a portion, which is configured to contact an upper edge of the electrode assembly adjacent to the bridge, and the bridge is d 2 , a length along the pouch sheet of the bridge is d 3 , a height of the electrode assembly seated on the pouch sheet is h, and a protruding height of the bridge with respect to the bottom surfaces of the pouch sheet is a,
the pouch sheet is formed to satisfy following conditional expressions: h≤d 1 +d 2 +d 3 and h/2≥a.

Assignees

• Lg Chern Ltd
• Lg Energy Solution Ltd

Inventors

• Park Sung Chui
• Kim Sang Wook
• Lee Dae Won
• Park Dong Hyeuk

Classifications

• H01M10/045 Primary

  Cells or batteries with folded plate-like electrodes · CPC title

• H01M50/54 Primary

  Connection of several leads or tabs of plate-like electrode stacks, e.g. electrode pole straps or bridges · CPC title

• B29C53/38

  by bending sheets or strips at right angles to the longitudinal axis of the article being formed and joining the edges · CPC title

• B29C51/266

  Auxiliary operations after the thermoforming operation (B29C51/42, B29C51/44, B29C51/46 take precedence) · CPC title

• H01M10/049

  Processes for forming or storing electrodes in the battery container · CPC title