Title of Invention	"A CURRENT COLLECTOR GRID FOR HIGH DENSITY RECHARGEABLE BATTERIES"
Abstract	This invention relates to a current collector grid. The current collector grid is used in high density rechargeable batteries. The current collector grid has a woven mesh of wire of a conducting material such as copper.

Full Text

FIELD OF INVENTION This invention relates to high energy density rechargeable batteries. In particulars this invention relates current collector grids for use in high energy density rechargeable batteries. BACKGROUND OF. INVENTION In the latest generation of high energy—density rechargeable batteries, particularly those based on lithium-ion use of thin current collectors of expanded— metal or perforated sheet of conductor metals like copper, aluminium etc. is common practice in cell construction. Grid thickness is of the order of 50 microns. Maximum open area with current manufacturing methods is around 40%. A disadvantage associated with both of the aforesaid collectors is that of costs. Manufacturing process for expanded metal gride are slow processes, perforated grids result in precious 40% loss of material in manufacture. Since copper is expensive, 40% loss is a major cost burden. It is known to provide the grids in the form of foldad or cut pieces with current collector tabs protruding on one edge. In another type of application, grids are provided in long strips (without tabs) in folded form and current is collected from un-perforated bands placed at regular intervals. The second alternative with which basic cell—laminate can be produced in wide—width long lengths (as with bolts of fabric) and cut to individual cell requirements at final stage, is obviously a more cost-effective manufacturing process, even though ionic conductivity between the negative and positive electrodes poses problems due to edge—proximity and requires additional processes to counter—act. OBJECTS OF THE INVENTION An object of this invention is to propose an improved current collector grid for use in high energy density rechargeable batteries. Another object of this invention is to propose an improved current collector grid for use in high energy density rechargeable batteries which is versatile with respect to openness of the mesh. Still another object of this invention is to propose an improved current collector grid for use in high energy density rechargeable batteries having a reduced ionic conductivity. Yet another object of this invention is to propose an improved current collector grid for use in high energy density rechargeable batteries which has a substantial cost reduction in comparison to the grids of the known art. DESCRIPTION OF THE INVENTION According to this invention there is provided a current collector grid for high density rechargeable batteries comprising a woven mesh of wire characterized by woven mesh of wire of a conducting material in one direction and threads of a non conducting material in the other direction. In accordance with this invention, the grid comprises a woven mesh of any suitable conducting material, such as copper. The manufacturing disadvantages of the prior art and results in substantial cost reduction. The grid is made from woven-mesh made out of copper wire drawn to the desired fine thickness on drawing lines with inter-stage annealing. This fine metal wire is then woven cloth fashion into a mesh of the desired openness on the looms of traditional zari-weavers. Advantage of weaving process is total flexibility in regard to: * Openness of the mesh, mesh can even be varied from segment to segment. * Opening possibility of using some strands of non- conductive thread in weft/warp in any desired pattern as shown in 4. Introduction of non- conductive materials at the edges is helpful in reduction of ionic conductivity. In accordance with another embodiment, the woven mesh comprises wire of a conducting material in one direction and threads of a non conducting material in the other direction. The non conducting threads are provided in the form of tab strips and inter piece dividers. DESCRIPTION WITH REFERENCE TO DRAWINGS Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings and wherein: Fig. 1 shows a collector grid of the known art; Fig. 2 2a and 2b shows the material forming the grid of the known art; Fig. 3 shows the grid of the present invention Fig. 4 shows another embodiment of the grid of the present invention. Referring to Fig. i, the grid 1 of the prior art comprises a sheet 2 of conducting material having collector tabs 3. Grid 1 may be formed of perforated foil sheet 5 (Fig. 2a) or expanded metal 4 (Fig. 2b). The disadvantages of such a sheet have been described hereinabove. In order to obviate the disadvantages associated with the grid of the prior art, the grid 6 of the present invention is woven from threads 7 of a conducting material along the warp and weft, and as shown in Fig. 3. In an alternative embodiment as shown in Fig, 4, the grid 8 is woven from threads 9 of a conducting along one direction and non conducting threads 10 along the other direction and such as to form tab strips 11 and inter piece divider. I CLAIM; 1. A current collector grid for high density rechargeable batteries comprising a woven mesh of wire characterized by woven mesh of wire of a conducting material in one direction and threads of a non conducting material in the other direction. 2. A current collector grids as claimed in claim 1 wherein the non conducting threads are provided in the form of tab strips and inter piece dividers. 3. A current collector grid for use in high energy density rechargeable batteries substantially as herein described and illustrated.

Documents:

927-del-2000-abstract.pdf

927-del-2000-claims.pdf

927-del-2000-correspondence-others.pdf

927-del-2000-correspondence-po.pdf

927-del-2000-description (complete).pdf

927-del-2000-drawings.pdf

927-del-2000-form-1.pdf

927-del-2000-form-19.pdf

927-del-2000-form-2.pdf

927-del-2000-form-3.pdf

927-del-2000-gpa.pdf

927-del-2000-petition-others.pdf