Methods for making reference electrode and lithium ion battery having the same

Abstract

The present disclosure relates to methods for making a reference electrode and a lithium ion battery having the reference electrode. The reference electrode obtained has a long service life, moreover, the manufacturing process is simple and can meet the industrial production requirements, making the production and the application of the lithium-ion battery with the reference electrode possible.

What is claimed is: 
     
         1 . A method for making a reference electrode, comprising:
 providing a reference electrode substrate and a current collecting metal sheet adhered with a tab binder;   welding the reference electrode substrate to a lower portion of the current collecting metal sheet;   melting lithium metal to liquid state, thereby obtaining a liquid lithium;   immersing a lower portion of the reference electrode substrate welded with the current collecting metal sheet into the liquid lithium and standing to coat a lithium metal layer on the lower portion of the reference electrode substrate, thereby obtaining a reference electrode welded with the current collecting metal sheet; and   taking out the reference electrode welded with the current collecting metal sheet from the liquid lithium, cooling, and warping a portion below the tab binder of the reference electrode with a separator, thereby obtaining a reference electrode wrapped with the separator.   
     
     
         2 . The method of  claim 1 , wherein the reference electrode substrate is a porous copper foam, a porous nickel foam, a copper mesh, or a nickel mesh. 
     
     
         3 . The method of  claim 1 , wherein before the welding, the reference electrode substrate is washed and then dried. 
     
     
         4 . The method of  claim 1 , wherein after the welding, an upper portion of the reference electrode substrate is overlapped with the lower portion of the current collecting metal sheet, and an area of the current collecting metal sheet is smaller than an area of the reference electrode substrate. 
     
     
         5 . The method of  claim 1 , after the welding, further comprising:
 vacuum drying the reference electrode substrate welded with the current collecting metal sheet at about 60° C. to about 90° C. under the water-free and oxygen-free condition for about  4  to about 7 hours, cooling, and then transferring into and preserving in a water-free and oxygen-free environment.   
     
     
         6 . The method of  claim 1 , wherein before the immersing, the liquid lithium is heated to about 200° C. to about 500° C. to remove an impurity on the surface of the liquid lithium under the water-free and oxygen-free condition. 
     
     
         7 . The method of  claim 1 , wherein the lower portion of the reference electrode substrate is immersed into the liquid lithium and rested for about 1 min to about 5 min to coat the lithium metal layer on the lower portion of the reference electrode substrate. 
     
     
         8 . The method of  claim 1 , wherein after the wrapping, the separator is wrapped tightly around the current collecting metal sheet and the reference electrode substrate. 
     
     
         9 . The method of  claim 1 , wherein a material of the current collecting metal sheet is nickel or aluminum. 
     
     
         10 . The method of  claim 1 , wherein a material of the separator is porous polypropylene, porous polyethylene, porous polypropylene coated with ceramic, porous polyethylene coated with ceramic, or non-woven fabric. 
     
     
         11 . The method of  claim 1 , wherein the reference electrode substrate has a pore size of about 50 μm to about 500 μm and a thickness of about 0.1 mm to about 1 mm. 
     
     
         12 . The method of  claim 1 , wherein a thickness of the current collecting metal sheet is about 0.1 mm to about 1 mm, and a length of the current collecting metal sheet is about 10 mm to about 30 mm. 
     
     
         13 . The method of  claim 1 , wherein the lithium metal layer has a thickness of about 10 μm to about 100 μm. 
     
     
         14 . A method for making a lithium ion battery having a reference electrode, comprising:
 providing a reference electrode substrate and a current collecting metal sheet adhered with a tab binder;   welding the reference electrode substrate to a lower portion of the current collecting metal sheet;   melting lithium metal to liquid state, thereby obtaining a liquid lithium;   immersing a lower portion of the reference electrode substrate welded with the current collecting metal sheet into the liquid lithium and standing to coat a lithium metal layer on the lower portion of the reference electrode substrate, thereby obtaining a reference electrode welded with the current collecting metal sheet;   taking out the reference electrode welded with the current collecting metal sheet from the liquid lithium, cooling, and warping a portion below the tab binder of the reference electrode with a separator, thereby obtaining a reference electrode wrapped with the separator;   interposing the reference electrode wrapped with the separator between a cell separator and an anode plate of a cell of the lithium ion battery and protrude an upper end of the reference electrode out from the cell of the lithium ion battery under the water-free and oxygen-free condition; and   packaging the lithium ion battery implanted with the reference electrode under the water-free and oxygen-free condition, thereby obtaining the lithium ion battery having the reference electrode.   
     
     
         15 . The method of  claim 14 , wherein an area of the reference electrode substrate is about 1% to about 10% of an area of an electrode plate of the lithium ion battery. 
     
     
         16 . The method of  claim 14 , wherein the upper end of the reference electrode is protruded out from the cell of the lithium ion battery for 1 mm to 2 mm. 
     
     
         17 . The method of  claim 14 , wherein the lithium ion battery implanted with the reference electrode is packaged by an aluminum plastic film under the anhydrous and oxygen-free condition.