A grid is obtained by punching or expanding a sheet comprising a pure lead (Pb: 99.99 mass % or more) plate having a lead-tin alloy layer formed at least on one side of the pure lead plate. By using it as a positive electrode of a lead-acid battery, the problem that a pure lead grid shows bad charge acceptance characteristics after deep discharge can be solved, maintaining the excellent trickle life performance which a pure lead grid shows originally.
1. A lead-acid battery comprising:
a positive electrode, a negative electrode and a separator lying between said positive electrode and said negative electrode;
wherein, as a grid of said positive electrode, a grid which is obtained by punching or expanding a sheet comprising a lead-tin alloy layer on only one surface of a pure lead, Pb: 99.99 mass % or more, plate is used.
2. The lead-acid battery according to claim 1 ,
wherein a ratio X % of said lead-tin alloy layer thickness to a total sheet thickness satisfies the formula 0.5≦X≦40.
3. The lead-acid battery according to claim 2 ,
wherein a ratio Y mass % of Sn content to lead-tin alloy layer mass satisfies the formula 0.5≦Y≦−0.625X+50.
4. The lead-acid battery according to claim 1 ,
wherein a ratio X % of said lead-tin alloy layer thickness to a total sheet thickness satisfies the formula 0.5≦X≦30.
5. The lead-acid battery according to claim 4 ,
wherein a ratio Y mass % of Sn content to lead-tin alloy layer mass satisfies the formula 0.5≦Y≦−0.625X+50.
6. The lead-acid battery according to claim 1 ,
wherein a ratio Y mass % of Sn content to said lead-tin alloy layer mass and a ratio X % of a lead-tin alloy layer thickness to a total sheet thickness satisfy the formula 0.5≦Y≦−0.625X+50.
7. The lead-acid battery according to claim 1 ,
wherein said lead-tin alloy layer is combined into a layer comprising said pure lead plate by a rolling process.
8. The lead-acid battery according to claim 1 ,
wherein said grid has a positive active material thereon.