Laminated battery cell and methods for creating the same

Abstract

Electrodes with a multilayer or monolayer composite separator are described. The multilayer composite separator comprises multiple individual composite separator layers. Each individual composite separator layer comprises inorganic particulate material(s) and organic polymer(s) with different inorganic particulate material/polymer weight ratios. The multilayer composite separator layer is constructed in a way such that the composite separator layer adjacent to the electrode active material contains a higher weight percentage of the inorganic particulate material and lower weight percentage of the organic polymer than the composite separator layer outermost from the electrode current collector. Laminated cells comprising a positive electrode, a negative electrode, a laminated multilayer or monolayer composite separator layer are described, wherein at least one of the electrodes has a multilayer or monolayer composite separator disposed onto the surface of the electrode. Methods of making such laminated cells are also described.

1 . A laminated electrochemical cell, comprising:
 a positive electrode comprising a positive electrode current collector, a positive electrode active material layer disposed on one or both sides of the positive electrode current collector;   a negative electrode comprising a negative electrode current collector, a negative electrode active material layer disposed on one or both sides of the negative electrode current collector; and   a porous multilayer composite separator layer comprising a first layer adjacent to one of either the positive or negative electrode and a second layer spaced apart from said positive or negative electrode by the first layer, the first and second layers comprised of an inorganic particulate material and a polymer material wherein the inorganic material is the predominant material in the first layer, and the polymer material is the predominant material in the second layer, wherein the thickness of said first layer is at least 80% of the total thickness of the multilayer composite separator; said first layer comprises greater than 50% inorganic particulate material by weight; and said second layer comprises greater than 50% organic polymer by weight.   and wherein the positive electrode and negative electrode are positioned in a facing relationship to form a laminate multilayer composite separator layer between the positive and negative electrodes.   
     
     
         2 . The laminated electrochemical cell of  claim 1 , wherein the said electrochemical cell is a prismatic cell. 
     
     
         3 . The laminated electrochemical cell of  claim 1 , wherein the said laminate multilayer composite separator layer has a thickness of about 2 to 40 μm. 
     
     
         4 . The laminated electrochemical cell of  claim 1 , wherein the said laminate multilayer composite separator layer has a thickness of about 10 to 30 μm. 
     
     
         5 . The laminated electrochemical cell of  claim 1 , wherein the said laminate multilayer composite separator layer has a thickness of about 20 μm. 
     
     
         6 . The laminated electrochemical cell of  claim 1 , wherein said first composite separator layer has an inorganic particulate material/organic polymer weight ratio of about 90:10 to about 60:40. 
     
     
         7 . The laminated electrochemical cell of  claim 1 , wherein said first porous monolayer composite separator layer has an inorganic particulate material/organic polymer weight ratio of about 70:30 to about 60:40; and said second porous monolayer composite separator layer has an inorganic particulate material/organic polymer weight ratio of about 40:60 to about 49:51. 
     
     
         8 . The laminated electrochemical cell of  claim 1 , wherein said organic polymer comprises a polymer which is electrochemically compatible with Li-ion cells. 
     
     
         9 . The laminated electrochemical cell of  claim 1 , wherein said organic polymer is selected from the group consisting of polyvinylidene fluoride (PVDF)-based polymers, such as poly(vinylidene fluoride) (PVDF) and its co- and terpolymers with hexafluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, poly(vinyl fluoride), polytetraethylene (PTFE), ethylene-tetrafluoroethylene copolymers (ETFE), polybutadiene, cyanoethyl cellulose, carboxymethyl cellulose and its blends with styrene-butadiene rubber, polyacrylonitrile, ethylene propylene diene terpolymers (EPDM), styrene-butadiene rubbers (SBR), polyimides, ethylene-vinyl acetate copolymers, polyacrylic acids and lithiated polyacrylic acids. 
     
     
         10 . The laminated electrochemical cell of  claim 1 , wherein said inorganic particulate material is selected from the group consisting of silica, alumina, titania, natural and synthetic zeolites, metal carbonates, zirconia, silicon phosphates, silicates and other electrochemically stable inorganic particles of the appropriate particle size. 
     
     
         11 . The laminated electrochemical cell of  claim 1 , wherein said inorganic particulate material has a particle size of about 4 nm to about 500 nm. 
     
     
         12 . The laminated electrochemical cell of  claim 1 , wherein said inorganic particulate material has a particle size of about 10 to 20 nm. 
     
     
         13 . The laminated electrochemical cell of  claim 1 , wherein said inorganic particulate material has a particle size of about 1 μm to about 6 μm. 
     
     
         14 . A portable electronic device comprising a laminated electrochemical cell of  claim 1 .