Polymer-lithium batteries and improved methods for manufacturing batteries

Abstract

Improved polymer batteries and improved methods of manufacturing such polymer batteries are provided. One improved method of manufacture involves the formation of a laminated array structure that includes a number of individual battery cells. After formation of the laminated array the individual batteries are singulated from the array by cutting, shearing or stamping. Other manufacturing improvements include the use of a printing process (e.g. stenciling) to form the cathodes, the use of permanent mask layers to contain and insulate the cathodes and anodes, and the use of a molten lithium deposition process for forming the anodes.

Description

CROSS REFERENCES TO RELATED APPLICATIONSThis application is related to copending application filed Jun. 2, 1993 and entitled "Package and Method for Fabricating a Battery Employing An Alkali-Metal Anode and Polymer Film Inks".FIELD OF THE INVENTIONThis invention relates generally to batteries and more particularly to thin batteries constructed with polymer films. Specifically, the invention is directed to improved polymer batteries and improved methods for making polymer batteries.BACKGROUND OF THE INVENTIONAdvancements in semiconductor technology have led to the production of large scale integrated circuits which have brought about a revolution in the electronics industry. Microelectronic components are now widely used in the production of a variety of electronic devices (e.g. portable computers, calculators, watches, cordless telephones, radios, tape recorders, security systems ). Development of such portable electronic devices has brought about the evolution of batteries as minia...

AI Technical Summary

Benefits of technology

The individual batteries have a laminated structure that includes a cathode substrate (i.e. a current collector), a cathode supported and insulated by the cathodic mask, a separator / electrolyte layer, an anode supported and insulated by the anode mask, and an anode substrate. Furthermore, the laminated array my be formed with more than one stack of cells (e.g. base stack, center stack, top stack) to form a stacked or multi-cell battery structure which provides higher battery voltages.

1. Discrete, deposited patterns of cathode material (in an array form) are used to minimize electrical shorting of the anode to the cathode during formation of individual battery cells and singulation of the individual battery cells from the array. A preferred method of depositing the cathode material is using a printing process such as pin transfer, screen or stencil printing.

2. The use of permanent mask layers in battery cell fabrication to minimize electrical shorting during formation and singulation of the individual battery cells.

4. The use of an integral support system (i.e. "studs" provided by the mask layers) that can prevent the separator / electrolyte material from being compressed or pushed into contact with the current collector or displacing the cathode material. This is particularly advantageous on larger or more flexible cells.

5. Staggered, etched or die cut patterns can be used for the anode and cathode substrates (i.e. current collectors) to prevent or minimize electrical shorting during battery cell formation and singulation of the batteries from the array.

Problems solved by technology

This is a relatively labor intensive procedure that involves the intricate assembly of a number of discrete components.

In particular, the stamping and handling of individual discs of lithium is costly and difficult, because lithium is expensive and highly reactive.

In general, this is a relatively complex manufacturing technique which requires relatively complicated and expensive manufacturing equipment.

Furthermore, many of the difficulties in manufacturing such polymer batteries are related to handling and assembling the lithium anodes, the cathodic polymers and the electrolytic polymers.

These problems are compounded because most prior art manufacturing procedures typically involve the formation of one battery cell at a time.

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