Sealed deep cycle lead acid battery

Claim 2

A maintenance-free, absorbed electrolyte, lead-acid cell capable of enduring deep discharge and rapid recharge cycling, with long cycle life, comprising: a container normally sealed from the atmosphere in service; a plurality of positive plates in said container, each of said plates comprising a self-supporting grid of a lead alloy containing no more than about 2% antimony based upon the total weight of the alloy, and positive active material on said grid; a plurality of negative plates in said container, each of said plates comprising a self-supporting grid of essentially antimony-free lead alloy and negative active material pasted on said grid; sulfuric acid electrolyte in an amount sufficient to provide a desired capacity and an electrolyte-starved condition; separator material intimately contacting and separating said positive and negative plates, said separator material being at least 70% porous, easily wetted, and capable of wicking the electrolyte; said electrolyte being substantially completely absorbed in said plates and separators; and said separators providing a sufficient void volume in service to permit transport of oxygen gas generated during recharge at a sufficient rate so that pressure in the cell does not normally exceed about 10 psig.

Claim 3

A lead-acid cell as claimed in claim 1 in which the container has a normally closed safety release valve capable of venting gases from the container to the atmosphere before pressure within the container exceeds a predetermined level not greater than 10 psig.

Claim 4

A lead-acid cell as claimed in claim 1 in which the cell capacity exceeds 25 AH.

Claim 5

A lead-acid cell as claimed in claim 1 in which the separator material is between about 75 and 95% porous.

Claim 6

A lead-acid cell as claimed in claim 1 in which the separator material is about 90% saturated with the electrolyte.

Claim 7

A cell as claimed in claim 1 wherein the grids of the positive are of a lead alloy containing antimony in an amount of about 0.5 to 2.0 and cadmium in an amount of about 0.5 to 2.0, both percentages being based upon the total weight of the alloy.

Claim 8

A cell as claimed in claim 6 wherein the grids of the positive are of a lead alloy containing antimony in an amount of about 1.2-1.8% and cadmium in an amount of about 1.2-1.8%, both percentages being based on the total weight of the alloy.

Claim 9

A cell as claimed in claim 1 wherein the active materials are formed from pastes essentially free of tetrabasic lead sulfate.

Claim 10

A cell as claimed in claim 1 wherein the negative active material has a density of from about 3.6 to 4.1 grams/cm. 3 .

Claim 11

A cell as claimed in claim 1 wherein the separator is a borosilicate glass material.

Claim 12

A battery comprising a plurality of cells according to claim 1.

Claim 13

A maintenance-free, sealed, absorbed electrolyte, lead-acid cell capable of enduring repeated deep discharge cyclic regimes, comprising: a container normally sealed from the atmosphere in service; a plurality of positive plates in said container, each of said plates comprising a self-supporting grid of a lead alloy containing no more than about 2% antimony based upon the total weight of the alloy, and positive active material pasted on said grid; a plurality of negative plates in said container, each of said plates comprising a self-supporting grid of essentially antimony-free lead alloy and negative active material pasted on said grid; an electrolyte absorbing and retaining separator material intimately contacting and separating said positive and negative plates said separator material having sufficient void space so that the oxygen diffusion rate at equilibrium approximately equals the rate at which oxygen is evolved; sulfuric acid electrolyte absorbed in said plates and separators, said plates and separators being sufficiently porous to retain sufficient electrolyte to provide a cell capacity of at least 25 ampere hours and an electrolyte-starved condition; and, said container having a normally closed relief valve capable of venting gases from the container to the atmosphere when pressure within said container is no greater than about 10 psig.

Claim 14

A maintenance-free, sealed, absorbed electrolyte, lead-acid cell capable of enduring repeated deep discharge cyclic regimes, comprising: a container normally sealed from the atmosphere in service; a plurality of positive plates in said container, each of said plates comprising a self-supporting grid of a lead alloy containing no more than about 2% antimony based upon the total weight of the alloy, and positive active material pasted on said grid; a plurality of negative plates in said container, each of said plates comprising a self-supporting grid of essentially antimony-free lead alloy and negative active material pasted on said grid; an electrolyte absorbing and retaining separator material intimately contacting and separating said positive and negative plates said separator material having sufficient void space so that the oxygen diffusion rate at equilibrium approximately equals the rate at which oxygen is evolved; sulfuric acid electrolyte absorbed in said plates and separators, said plates and separators being sufficiently porous to retain sufficient electrolyte to provide a cell capacity of at least 25 ampere hours and an electrolyte-starved condition; and, said container having a normally closed relief valve capable of venting gases from the container to the atmosphere when pressure within said container is no greater than about 10 psig.