Battery grid with varied corrosion resistance
A battery grid is disclosed. The battery grid includes a pattern of grid wires. The pattern includes a grid wire having a first segment with a first corrosion resistance and a second segment with a second corrosion resistance which is less than the first corrosion resistance. The second segment corrodes at a rate which is faster than the corrosion rate of the first segment so as to dynamically release internal stress and control grid growth of the battery grid during its service life. A battery includes said grid and a method of forming said grid are also disclosed.
1. A lead-acid battery comprising a plurality of stamped, positive battery grid plates each having a frame with a top, a first side, a second side, and a bottom, wherein the top has a lug, and further wherein a plurality of grid wires having a first microstructure are interconnected within each of the frames to create interstices therebetween, the positive battery grid plates alternating with negative battery grid plates and interleaved with separators to form a stack, the stack fitting within a battery housing, one or more of the plurality of grid wires of the positive battery grid plates having a primary deformation of a first magnitude at one or more pre-selected locations, the first magnitude being an insufficient magnitude to alter the first microstructure, and one or more of the plurality of grid wires of the positive battery grid plates having a secondary deformation of a second magnitude greater than the first magnitude imparted upon the one or more of the plurality of grid wires at one or more pre-selected locations, the second magnitude being a magnitude sufficient to alter the first microstructure into a second microstructure different from the first microstructure.
2. The lead-acid battery of claim 1 wherein the one or more pre-selected locations of the secondary deformation are frangible and located to relieve stresses resulting from anticipated growth of the positive battery grid plate within the housing.
3. The lead-acid battery of claim 1 wherein each of the battery grid plates has x number of interstices, each of the interstices being bounded by continuous lengths of grid wires and wherein there are less than x number of interstices after anticipated growth of the positive grid plate within the housing.
4. The lead-acid battery of claim 1 wherein the grid wires are frangible at the locations of the secondary deformation before the remainder of the grid wires when subject to corrosion.
5. The lead-acid battery of claim 1 wherein the one or more pre-selected locations are more susceptible to corrosion than the remainder of the grid wires.
6. A lead-acid battery comprising a plurality of stamped, positive battery grid plates each having a frame with a top, a first side, a second side, and a bottom, wherein the top has a lug, and further wherein a plurality of grid wires having a first microstructure are interconnected within each of the frames to create interstices therebetween, the positive battery grid plates alternating with negative battery grid plates and interleaved with separators to form a stack, the stack fitting within a battery housing, one or more of a plurality of the grid wires of the positive battery grid plates having one or more primary deformations of a first magnitude, wherein the first magnitude is of an insufficient magnitude to alter the first microstructure, and one or more of the grid wires having a secondary deformation of a second magnitude greater than the first magnitude, wherein the secondary deformation is of a sufficient magnitude to alter the first microstructure into a second microstructure different from the first microstructure and which is more susceptible to corrosion and is formed in the grid wires at pre-selected locations.
7. The lead-acid battery of claim 6 wherein the pre-selected locations of the secondary deformations are frangible and located to relieve stresses resulting from anticipated growth of the positive battery grid plate within the housing.
8. The lead-acid battery of claim 6 wherein each of the battery grid plates has x number of interstices, each of the interstices being bounded by continuous lengths of grid wires and wherein there are less than x number of interstices after anticipated growth of the positive grid plate within the housing.
9. The lead-acid battery of claim 1 , wherein the secondary deformation is selected from the group consisting of laser melting, heat treatment, perforation, severe plastic deformation, coining, skew rolling, particle bombardment, water jet machining, vacuum forming, and application of high pressure air, arcs, or sputter pumps.
10. The lead-acid battery of claim 6 , wherein the secondary deformation is selected from the group consisting of laser melting, heat treatment, perforation, severe plastic deformation, coining, skew rolling, particle bombardment, water jet machining, vacuum forming, and application of high pressure air, arcs, or sputter pumps.