Electrochemical device using multicomponent composite membrane film

1. An electrochemical element comprising electrochemical cells which are multiply-stacked with a separator layer interposed between each stacked cell, wherein said separator layer is a multi-component composite membrane comprising:

a) a porous polymeric support layer; and

b) a porous gellable polymer layer which is formed on one side or both sides of the porous polymeric support layer,

wherein the porous polymeric support layer and the porous gellable polymer layer have the same or different pore size and are united with each other.

2. An electrochemical element comprising electrochemical cells which are multiply-stacked, wherein

a) said electrochemical cells are formed by stacking:

i) fuel cells having a positive electrode, a separator layer, and an negative electrode sequentially as a basic unit; or

ii) {circle around (1)} bicells having a positive electrode, a separator layer, a negative electrode, another separator layer, and another positive electrode sequentially as a basic unit or

{circle around (2)} bicells having a negative electrode, a separator layer, a positive electrode, another separator layer, and another negative electrode sequentially as a basic unit; and

iii) a separator layer interposed between each stacked cell;

b) each of said separator layers comprise a multi-component composite membrane comprising:

i) a porous polymeric support layer and

ii) a porous gellable polymer layer which is formed on one side or both sides of the porous polymeric support layer,

wherein said porous polymeric support layer and the porous gellable polymer layer have the same or different pore size and are united with each other.

3. The electrochemical element according to claim 2 , wherein a material of the porous polymeric support layer of b) i) is at least one selected from the group consisting of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polypropylene, high crystalline polypropylene, polyethylene-propylene copolymer, polyethylene-butylene copolymer, polyethylene-hexene copolymer, polyethylene-octene copolymer, polystyrene-butylene-styrene copolymer, polystyrene-ethylene-butylene-styrene copolymer, polystyrene, polyphenylene oxide, polysulfone, polycarbonate, polyester, polyamide, polyurethane, polyacrylate, polyvinylidene chloride, polyvinylidene fluoride, polysiloxane, polyolefin ionomer, polymethyl pentene, hydrogenated oligocyclopentadiene (HOCP), and a copolymer thereof or a derivative thereof.

4. The electrochemical element according to claim 2 , wherein a material of the porous gellable polymer layer of b) i) is at least one selected from the group consisting of polyvinylidene fluoride, polyvinylidene fluoride-chlorotrifluoroethylene copolymer, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, polypropylene oxide, polybutylene oxide, polyurethane, polyacrylonitrile, polyacrylate, polymethyl methacrylate, polyacrylic acid, polyamide, polyacrylamide, polyvinyl acetate, polyvinylpyrrolidone, polytetraethylene glycol diacrylate, polysulfone, polyphenylene oxide, polycarbonate, polyester, polyvinylidene chloride polysiloxane, polyolefin ionomer, and a copolymer thereof or a derivative thereof.

5. The electrochemical element according to claim 2 , wherein the porous gellable polymer layer comprises at least one lithium salt selected from the group consisting of LiSCN, LiClO 4 , LiCF 3 SO 3 , LiAsF 6 , LiN(CF 3 SO 2 ) 2 , and LiBF 4 .

6. The electrochemical element according to claim 2 , wherein the porous gellable polymer layer comprises at least one porous inorganic particle selected from the group consisting of SiO 2 , TiO 2 , Al 2 O 3 , MgO, and B 2 O 3 .

7. The electrochemical element according to claim 2 , wherein a pore size of the porous polymeric support layer of b) i) ranges from 0.001 to 10 μm, and its thickness ranges from 1 to 50 μm; and a pore size of the porous gellable polymer layer of b) ii) is at most 10 μm, and its thickness ranges from 0.01 to 25 μm.

8. The electrochemical element according to claim 2 , wherein the multi-component composite membrane of b) is prepared by the steps of:

i) providing a porous polymeric support;

ii) dissolving a gellable polymer in a solvent in order to prepare a gellable polymer solution;

iii) forming a gellable polymer layer on one side or both sides of the support layer film of i) by coating the support layer film with the gellable polymer solution of ii) in order to prepare a multiple layer; and

iv) stretching and heat-setting the multiple layer of iii).

9. The electrochemical element according to claim 8 , wherein the high-temperature-stretching is performed after low-temperature-stretching of the multiple layer in the stretching process of iv).

10. The electrochemical element according to claim 8 , wherein the heat-setting of iv) is performed under the condition of tension at 50° C. or at most a temperature of the polymer melting point of the gellable polymer layer, for 10 seconds to an hour.

11. The electrochemical element according to claim 8 , wherein the porous polymeric support layer of i) is prepared by injecting the polymer into an extruder equipped with a T-die or a tubular die in order to extrude the polymer, and annealing it in a dry oven at from room temperature to a polymer melting point of the support layer at most.

12. The electrochemical element according to claim 8 , wherein the solvent of ii) is at least one selected from the group consisting of 1-methyl-2-pyrrolidone (NMP), acetone, ethanol, n-propanol, n-butanol, n-hexane, cyclohexanol, acetic acid, ethyl acetate, diethyl ether, dimethyl formamide (DMF), dimethylacetamide (DMAc), dioxane, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), cyclohexane, benzene, toluene, xylene, water, and a derivative thereof.