PREPARATION PROCESS FOR PREVENTING DEFORMATION OF JELLY-ROLL TYPE ELECTRODE ASSEMBLY

• US 20100285341A1
• Filed: 10/08/2008
• Published: 11/11/2010
• Est. Priority Date: 10/12/2007
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Lee, Jinsoo, Yun, Youngkwang, Ryu, Sangbaek, Lee, Hyang Mok, Kim, SooRyoung, Choi, Byungjin
• Granted Patent: US 8,870,978 B2
• Time in Patent Office: Days
• US Class Current: 429/94
• CPC Class Codes: H01M 10/0409 for cells with wound electrodes
• CPC Class Codes: H01M 10/0431 Cells with wound or folded electrodes H01M10/045 takes precedence
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/0565 Polymeric materials, e.g. gel-type or solid-type
• CPC Class Codes: H01M 10/0587 of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
• CPC Class Codes: H01M 10/4235 Safety or regulating additives or arrangements in electrodes, separators or electrolyte H01M10/4242 takes precedence
• CPC Class Codes: H01M 50/119 Metals
• CPC Class Codes: H01M 50/121 Organic material
• CPC Class Codes: H01M 50/124 having a layered structure
• CPC Class Codes: H01M 50/446 Composite material consisting of a mixture of organic and inorganic materials
• CPC Class Codes: H01M 50/46 Separators, membranes or diaphragms characterised by their combination with electrodes
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/49108 Electric battery cell making
• CPC Class Codes: Y10T 29/49115 including coating or impregnating

Abstract

Provided is a method for fabrication of a jelly-roll type electrode assembly having a cathode/separation membrane/anode laminate structure, including: (a) coating both sides of a porous substrate with organic/inorganic composite layers, each of which includes inorganic particles and an organic polymer as a binder, so as to fabricate a composite membrane; and (b) inserting one end of a sheet laminate comprising a cathode sheet and an anode sheet as well as the composite membrane into a mandrel, winding the sheet laminate around the mandrel, and then, removing the mandrel, wherein the organic/inorganic composite layer includes microfine pores capable of moderating a variation in volume during charge/discharge of a secondary battery and an interfacial friction coefficient between the composite membrane and the mandrel is not more than 0.28.

Claims

1. A method for manufacturing a jelly-roll type electrode assembly having a cathode/separation membrane/anode laminate structure, including:

(a) coating both sides of a porous substrate with organic/inorganic composite layers, each of which includes inorganic particles and an organic polymer as a binder, so as to fabricate a composite membrane; and

(b) inserting one end of a sheet laminate comprising a cathode sheet and an anode sheet as well as the composite membrane into a mandrel, winding the sheet laminate around the mandrel, and then, removing the mandrel,

wherein the organic/inorganic composite layer includes microfine pores capable of moderating a variation in volume during charge/discharge of a secondary battery, and an interfacial friction coefficient between the composite membrane and the mandrel is not more than 0.28.

2. The method according to claim 1, wherein the composite membrane is formed by a process including:

(i) dissolving an organic polymer, which is capable of inducing a binding force between inorganic particles and adhesion of the inorganic particles to a surface of a substrate, in a solvent (‘

first solvent’

) to prepare a solution;

(ii) adding the inorganic particles to the prepared solution to prepare an organic/inorganic coating solution;

(iii) immersing a porous substrate in the coating solution through dip-coating, so as to form coating layers on both sides of the porous substrate; and

(iv) removing the solvent to produce an organic/inorganic composite layer having microfine pores.

3. The method according to claim 2, wherein the organic polymer is at least one or two selected from a group consisting of:

polyvinylidene fluoride;

polyvinylenefluoride-co-hexafluoropropylene;

polyvinylidenefluoride-co-trichloroethylene;

polyvinylidenefluoride-chlorotrifluoroethylene;

polymethylmethacrylate;

polyacrylonitrile;

polyvinylpyrrolidone;

polyvinylacetate;

ethylene vinyl acetate copolymer;

polyethyleneoxide;

cellulose acetate;

cellulose acetate butyrate;

cellulose acetate propionate;

cyanoethylpullulan;

cyanoethyl polyvinylalcohol;

cyanoethyl cellulose;

cyanoethyl sucrose;

pullulan;

carboxy methyl cellulose;

acrylonitrile styrene butadiene copolymer; and

polyimide.

4. The method according to claim 3, wherein the organic polymer is polyvinylidene fluoride-chlorotrifluoroethylene.

5. The method according to claim 2, wherein the first solvent is at least one or two selected from a group consisting of:

acetone;

tetrahydrofuran;

methylene chloride;

chloroform;

dimethyl formamide (DMF);

N-methyl-2-pyrrolidone (NMP);

cyclohexane;

water; and

mixtures thereof.

6. The method according to claim 2, wherein the inorganic particle is at least one or two selected from a group consisting of:

BaTiO₃, Pb(Zr, Ti)O₃ (PZT), Pb<sub>1−

x</sub>La_xZr<sub>1−

y</sub>Ti_yO₃ (PLZT), Pb(Mg₃Nb_2/3)O₃—

PbTiO₃ (PMN-PT), hafnia (HfO₂) SrTiO₃, SnO₂, CeO₂, MgO, NiO, CaO, ZnO, ZrO₂, Y₂O₃, Al₂O₃, TiO₂, and mixtures thereof and has a particle diameter ranging from 0.001 to 10 μ

m.

7. The method according to claim 2, wherein the inorganic particle in step (ii) is added to the prepared solution after being dispersed in a second solvent.

8. The method according to claim 7, wherein the second solvent has an evaporation rate different from that of the solvent for dissolving the organic polymer in step (i) (that is, the first solvent) and is selected from ketones and alcohols.

9. The method according to claim 7, wherein the second solvent is methanol or methylethylketone (MEK).

10. The method according to claim 1, wherein the organic/inorganic composite layer includes microfine pores, each of which has a diameter ranging from 0.1 to 50 μ

m and a permeability (or porosity) ranging from 100 to 1,000 sec/100 cc.

11. The method according to claim 1, wherein a coating thickness of the organic/inorganic composite layer ranges from 1 to 10 μ

m.

12. The method according to claim 1, wherein the interfacial friction coefficient is not more than 0.25.

13. The method according to claim 1, wherein lowered interfacial friction between the composite membrane and the mandrel is achieved by reducing a molecular weight of the organic polymer as the binder.

14. The method according to claim 1, wherein the organic polymer has a molecular weight ranging from 100,000 to 1,000,000 when the organic polymer is polyvinylidene fluoride (PVdF).

15. The method according to claim 1, wherein lowered interfacial friction between the composite membrane and the mandrel is achieved by reducing a molecular weight of the organic polymer as the binder.

16. The method according to claim 15, wherein the coating material is diamond like carbon (DLC).

18. A jelly-roll type electrode assembly fabricated by the method according to claim 1, wherein an organic/inorganic composite layer, which includes microfine pores capable of moderating a variation in volume during charge/discharge of a secondary battery, is formed on both sides of a porous substrate for fabricating a separation membrane, and the organic/inorganic composite layer has an interfacial friction coefficient relative to a mandrel used for manufacturing the jelly-roll type electrode assembly of not more than 0.28.

19. A secondary battery having the jelly-roll type electrode assembly according to claim 18 built in a battery case.

20. The secondary battery according to claim 19, wherein the battery case is a pouch type case consisting of a laminate sheet comprising a resin layer and a metal layer.

17. A composite membrane for a secondary battery comprising:

(i) dissolving an organic polymer, which is capable of inducing a binding force between inorganic particles and adhesion of the inorganic particles to a surface of a substrate, in a solvent to prepare a solution;

(ii) adding the inorganic particles to the prepared solution to prepare an organic/inorganic coating solution;

(iii) immersing a porous substrate in the coating solution through dip-coating, so as to form coating layers on both sides of the porous substrate; and

(iv) removing the solvent to produce an organic/inorganic composite layer having microfine pores,

wherein the organic/inorganic composite layer includes microfine pores capable of moderating a variation in volume during charge/discharge of the secondary battery, and the interfacial friction coefficient (μ

) between the composite membrane and a mandrel used for manufacturing a jelly-roll type electrode assembly is not more than 0.28.