US 6,592,686 B2 · Lead and lead alloys with enhanced creep and/or intergranular corrosion resistance, especially for lead-acid batteries and electrodes therefor

Abstract

Recrystallized lead and lead alloy positive electrodes for lead acid batteries having an increased percentage of special grain boundaries in the microstructure, preferably to at least 50%, which have been provided by a process comprising steps of working or straining the lead or lead alloy, and subsequently annealing the lead or lead alloy. Either a single cycle of working and annealing can be provided, or a plurality of such cycles can be provided. The amount of cold work or strain, the recrystallization time and temperature, and the number of repetitions of such steps are selected to ensure that a substantial increase in the population of special grain boundaries is provided in the microstructure, to improve resistance to creep, intergranular corrosion and intergranular cracking of the electrodes during battery service, and result in extended battery life and the opportunity to reduce the size and weight of the battery.

Claims23

Dependent claims

Recrystallized lead or lead alloy having a special grain boundary percentage wherein the percentage of special grain boundaries comprises at least 50% of the total grain boundaries thereof;

said lead or lead alloy having a hardness after recrystallization which is not greater than the hardness of said lead or lead alloy before recrystallization;
and said alloy consisting essentially of lead alloyed with Ag, Sn, Cu, Zn, As, Bi, Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba or Ra.

Recrystallized lead or lead alloy positive lead-acid battery electrodes which have been processed to improve at least one of the properties of (i) creep, (ii) intergranular cracking and (iii) intergranular corrosion resistance, by subjecting said lead or lead alloy to at least one cycle consisting of the sequential steps of:

a. cold working the lead or lead alloy by an amount of approximately 10-80%;
and
b. annealing the lead or lead alloy at a temperature m the range of 150-280° C. for a period in the range of from 10 seconds to 20 minutes, sufficient to effect recrystallization of the lead or lead alloy and a substantial increase in the concentration of special grain boundaries thereof
wherein the percentage of special grain boundaries comprises at least 50% of the total grain boundaries thereof;
and said lead alloy consists essentially of lead and a metal alloyed therewith, said metal alloyed with said lead being selected from the group consisting of Ag, Sn, Cu, Zn, As, Bi, Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba or Ra.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application

09/935,704Filed 24 Aug 2001 · continuation

Priority

1 Mar 1996

Published

US 2002/0050311 A12 May 2002

Granted

15 Jul 2003

Term ends

Not estimatedThe source records don’t support an estimate.

Classification9 codes

C22C 11/00
Alloys based on lead
C22F 1/12
Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working: of lead or alloys based thereon
H01M 4/685
For use in lead-acid accumulators: lead alloys
H01M 4/82
Carriers or collectors: multi-step processes for manufacturing carriers for lead-acid accumulators

Family

Application08/609,327Parent of this continuation · filed 1 Mar 1996

Application08/835,926Parent of this continuation-in-part · filed 8 Apr 1997

Application08/977,518Parent of this continuation-in-part · filed 24 Nov 1997

Application09/412,610Parent of this continuation · filed 6 Oct 1999

US 2002/0050311 A1Pre-grant publication · published 2 May 2002

US 6,342,110 B1Parent of this continuation

Application09/412,610Parent of this continuation-in-part

Application08/835,926Parent of this continuation

US 6,592,686 B2This patent

From the US filing history. Foreign family members aren’t listed.

Lead and lead alloys with enhanced creep and/or intergranular corrosion resistance, especially for lead-acid batteries and electrodes therefor

Life of this patent

Lead and lead alloys with enhanced creep and/or intergranular corrosion resistance, especially for lead-acid batteries and electrodes therefor

Life of this patent

Abstract

Claims23