Yesterday Panasonic unveiled new rechargeable batteries in their Evolta series [JP], which clearly top existing products in terms of lifetime. In Japan, they will go on sale on October 1 (no word on availability outside this country yet).

Users can supposedly recharge the nickel-metal hydride batteries up to 1,200 times, around 20% more than existing Evolta products and Sanyo’s Eneloop batteries. Panasonic improved the performance by evenly distributing an alloy in negative electrodes, which can absorb hydrogen. Now, the batteries last 10% longer (compared to previous Evolta products).

In Japan, four of the new batteries (AA version) will retail for $15. Panasonic wants to produce 1.1 million batteries per month.