Electrochemical cell with improved internal contact

a technology of internal contact and electrochemical cells, which is applied in the direction of cell components, final product manufacturing, sustainable manufacturing/processing, etc., can solve problems such as anode disconnects, and achieve the effects of improving contact reliability, reliable pressure contact, and increasing tolerance of variability in manufacturing

Inactive Publication Date: 2009-03-26
EVEREADY BATTERY CO INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0013]An object of the present invention is to provide reliable pressure contact between an electrode lead and the side wall of the cell container. Additional advantages of the invention can include, but are not limited to, improved contact reliability, increased tolerance of variability in manufacturing, reduced number of cell components, improved ease of manufacturing, reduced manufacturing scrap and reduced product cost.
[0015]A further object of the present invention is to provide an electrochemical cell having a lithium negative electrode free of a separate current collector and a lead having a relatively short length connected directly to the lithium electrode and to a portion of the cell container thereby providing the cell with an increased internal area, preferably available for active materials.
[0016]Yet another object is to provide a negative electrode lead having a relatively small contact area with the lithium foil electrode, such as embodied by reduced lead length or distance in contact with a width of the electrode, without substantially impacting cell service.
[0017]Still another object is to provide a negative electrode lead connected to a lithium foil electrode of a primary cell having a design that prevents lithium from being isolated from the lead during discharge which can prevent consumption of the lithium and reduce cell service life.
[0019]Still another object of the invention is to provide an electrochemical cell that is anode deficient and that has an interfacial, theoretical anode to cathode input capacity ratio of less than 1.0, wherein substantially all interfacially oriented negative electrode active material is consumed without substantial loss of performance, even when utilizing a negative electrode lead having relatively little area in contact with the negative electrode that is free of a current collector.

Problems solved by technology

Significantly, because the lithium anode is consumed during discharge, having an underbalance of lithium means that the anode may suffer disconnects if there are any dissimilarities in the electrodes.

Method used

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  • Electrochemical cell with improved internal contact
  • Electrochemical cell with improved internal contact
  • Electrochemical cell with improved internal contact

Examples

Experimental program
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Effect test

example 1

[0107]Computer modeling was used to evaluate several negative electrode lead designs suitable for use in FR6 and FR03 cells with electrode assemblies similar to that illustrated in FIG. 1. The model was used to determine the spring force that could be exerted by the terminal end of a lead similar to the negative electrode lead in FIGS. 1 and 2. The spring force determined should approximate the amount of force exerted by the terminal portion of the lead against the inside surface of the side wall of the can.

[0108]The model used the following material properties for 0.051 mm (0.002 inch) thick nickel plated, cold rolled steel strip for the leads: Young's modulus=2.07×108 Pa (3.00×107 lb. / in2), Poisson's ratio=0.285 and initial yield strength=251,000 Pa (36,400 lb. / in2).

[0109]Three different shapes were evaluated for the terminal portion of the lead (the portion adjacent to the external surface of the electrode assembly, above the bend around the bottom of the electrode assembly, prio...

example 2

[0119]Ten lots of FR6 cells, similar to cell 10 in FIGS. 1 and 2, were made to evaluate cell characteristics and performance. Each cell in Lots 1 and 2 had a 0.0254 mm (0.001 inch) thick strip of polyethylene film wrapped around the electrode assembly circumference. The average electrode assembly outside diameter (including the strip of polyethylene film was 13.06 mm (0.514 inch). Each cell in Lots 3-10 had no outer wrap of polyethylene film, and the average outside diameter of the electrode assembly was 12.95 mm (0.510 inch). In all lots the average inside diameter of the can was 13.41 mm (0.528 inch). In all lots the negative electrode lead was made from a thin strip of conductive metal 4.75 mm (0.187 inch) wide, cut to a length of 55.9 mm (2.20 inch). One end of the lead was attached to the lithium negative electrode near its outer end, so that the terminal end of the lead protruded from the bottom end of the assembled electrode assembly, where it was bent outward and then upward...

example 3

[0122]Eight lots of FR6 cells, similar to cell 10 shown in FIGS. 1 and 2, were constructed to determine average service life of the cells. The cells of each lot had an interfacial, theoretical A / C input capacity ratio of 0.92.

[0123]Each of the Control Lot 1 and Lots 11-14 were identical with exception to the negative electrode lead as explained hereinbelow. The negative electrode consisted of lithium alloy foil having an aluminum content of about 0.5 weight %. Cells of Control Lot 1 included a nickel plated cold rolled steel negative electrode lead welded to 96% of the width of the lithium foil and had an overall length of 55.80 mm (2.200 inches). Cells of Lot 11 had an anode lead directly connected to 50% of the width of the lithium foil and an overall length of 37.97 mm (1.495 inches). Cells of Lot 12 had a nickel plated cold rolled steel negative electrode lead that extended 25% of the width of the lithium foil and an overall length of 28.22 mm (1.111 inches). Cells of Lot 13 had...

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Abstract

Electrochemical battery cells with strip-like electrodes and having a pressure contact between a lead from one of the electrodes and a side wall of the cell container. An electrochemical cell having a spiral wound electrode assembly having an internal lead in direct pressure contact with a lithium foil negative electrode free of a separate current collector and in contact with an inner portion of the cell container, wherein specified contact between the lead and lithium foil provides current flow between the container and foil.

Description

FIELD OF THE INVENTION[0001]This invention relates to electrochemical battery cells with strip-like electrodes and having a pressure contact between a lead from one of the electrodes and a side wall of the cell container. In a further embodiment, the present invention relates to an electrochemical cell having a spiral wound electrode assembly having an internal lead in direct pressure contact with a lithium foil negative electrode free of a separate current collector and in contact with an inner portion of the cell container, wherein specified contact between the lead and lithium foil provides current flow between the container and foil.BACKGROUND OF THE INVENTION[0002]Cells with adjacent positive and negative electrode strips can be used to provide good high rate discharge performance. Electrode assemblies containing such strips can include one or more pairs of flat, folded or spirally wound positive and negative electrodes. Cells can have housings including containers made from el...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H01M4/00H01M6/10H01M50/528H01M50/107H01M50/533H01M50/534H01M50/538
CPCH01M2/02H01M2/263H01M10/058H01M10/0525H01M2/266Y02E60/10H01M50/538Y02P70/50H01M50/534H01M50/533H01M50/107
Inventor KAPLIN, DAVID AARON
Owner EVEREADY BATTERY CO INC
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