Electrode assembly having high flexibility and battery cell including the same

Patent metadata

Field	Value
Publication number	US-2018301760-A1
Application number	US-201715767451-A
Country	US
Kind code	A1
Filing date	Mar 31, 2017
Priority date	Mar 31, 2016
Publication date	Oct 18, 2018
Grant date	—

Abstract

The present invention provides an electrode assembly, including two or more positive electrode plates and two or more negative electrode plates laminated with each of separators interposed therebetween, wherein both side end portions of the electrode assembly are bent together in the same direction by a curvature radius (R) satisfying the following Equation 1:
S [{1/ln( x/y )}* t]=R   1
wherein t is an average thickness (mm) of the laminated electrode assembly, x is a horizontal length of the electrode assembly, and y is a vertical length of the electrode assembly, and S is a constant of 10 or more, and ln(x/y)≥1.

First claim

1 . An electrode assembly comprising two or more positive electrode plates and two or more negative electrode plates laminated with each of separators interposed therebetween,
wherein both side end portions of the electrode assembly are bent together in the same direction by a curvature radius (R) satisfying the following Equation 1:
S[{ 1/ln( x/y )}* t]=R   1

wherein t is an average thickness (mm) of the laminated electrode assembly, x is a horizontal length of the electrode assembly, and y is a vertical length of the electrode assembly, and S is a constant of 10 or more, and ln(x/y)≥1.

2 . The electrode assembly of claim 1 , wherein the curvature radius (R) is 5 mm to 40 mm.

3 . The electrode assembly of claim 1 , wherein the horizontal length (x) is 5 mm to 500 mm.

4 . The electrode assembly of claim 1 , wherein a positive electrode lead and a negative electrode lead protrude side by side in a parallel direction to the vertical length (y), or in an opposite direction to each other, or protrude side by side in a parallel direction to the horizontal length (x), or in an opposite direction to each other.

5 . The electrode assembly of claim 1 , wherein the laminated electrode assembly has the average thickness (t) of 0.2 mm to 1.8 mm.

6 . The electrode assembly of claim 1 , wherein the constant S is 10 to 15.

7 . The electrode assembly of claim 1 , wherein the positive electrodes, the negative electrodes and inside separators interposed therebetween are sequentially laminated alternately between a first outside separator and a second outside separator, and
a portion of or entire surface of the separators is mutually joined to at least one of the positive electrode, the negative electrode and a separator facing the separators.

8 . The electrode assembly of claim 7 , wherein the electrode and the separator are laminated in an order of the first outside separator/the positive electrode/the inside separator/the negative electrode/the second outside separator,
an adhesive layer including an adhesive material is coated on outer surfaces of the separators, the first outer separator is joined to a first positive electrode surface of the positive electrode facing the first outer separator by the adhesive layer, a second positive electrode surface of the positive electrode which is an opposite surface of the first positive electrode surface is joined to the inside separator, the inside separator is joined to a first negative electrode surface of the negative electrode facing the inside separator, and a second negative electrode surface of the negative electrode which is an opposite surface of the first negative electrode surface is joined to the second outside separator.

9 . The electrode assembly of claim 7 , wherein the adhesive layer including an adhesive material is coated on surplus portions of the separators having a larger size than a size of the positive electrode and the negative electrode, at least a portion of the surplus portion of the first outside separator is joined to a surplus portion of a first surface of the inside separator by the adhesive layer, and
the surplus portion of a second surface of the inside separator which is an opposite surface of the first surface is joined to at least a portion of the surplus portion of the second outside separator.

10 . The electrode assembly of claim 9 , wherein the surplus portion of the first outside separator is joined to the surplus portion of the first surface of the inside separator with unjoined portions being disposed at regular intervals, and the surplus portion of the second surface of the inside separator may be joined to the surplus portion of the second outside separator with unjoined portions being disposed at regular intervals.

11 . The electrode assembly of claim 9 , wherein the surplus portion of the first outside separator is joined to the entire surplus portion of the first surface of the inside separator, and the surplus portion of the second surface of the inside separator is joined to the entire surplus portion of the second outside separator.

12 . The electrode assembly of claim 8 , wherein the adhesive material is one or more selected from the group consisting of polyfluorovinylidene (PVdF), polyvinylalcohol (PVOH), carboxylmethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, and various copolymers.

13 . A battery cell having a structure in which the electrode assembly of claim 1 is stored in a variable battery case together with an electrolyte solution,
wherein both side end portions of the electrode assembly and the battery case in positions of facing each other are bent together in the same direction, so that a curved surface is formed on an outer surface of the battery cell.

14 . The electrode assembly of claim 9 , wherein the adhesive material is one or more selected from the group consisting of polyfluorovinylidene (PVdF), polyvinylalcohol (PVOH), carboxylmethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, and various copolymers.

Assignees

• Lg Chemical Ltd

Inventors

• You Min Kyu
• Kang Sung Joong
• Mok Eun Kyung
• Uhm In Sung

Classifications

• H01M10/0585 Primary

  of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M50/136

  Flexibility or foldability · CPC title

• H01M50/105

  Pouches or flexible bags · CPC title

• H01M50/553

  Terminals adapted for prismatic, pouch or rectangular cells · CPC title