At the Intel Developer Forum in Beijing, China, Intel is advocating a standardized battery design for ultrabooks. Although the firm concedes that high-end ultrabook chassis may require custom batteries for "industrial design reasons," it argues that standardization would allow mainstream ultrabooks to hit lower price points. Savings of 5-10% are quoted in the presentation slides posted by Liliputing. Standardization would also make it easier for notebook makers to source batteries, the slides contend.
Intel is proposing a battery with a footprint of 60 x 80 mm. It would use standard cylindrical cells measuring 16 mm in diameter, the sweet spot for capacity, size, and energy density, according to Intel. There are power delivery considerations, as well. Intel has some specific recommendations about power burst ratings to ensure that its Turbo mechanism has sufficient wattage to kick the CPU into high gear when running on battery alone.
I'm for anything that can make ultrabooks cheaper. There's another potential benefit to standardizing batteries, too. Removeable batteries remain relatively rare in the super-slim realm, but standardization could make it easier to integrate them into ultrabook chassis. Being able to swap in a new power source would certainly help the shorter battery life typical of ultra-skinny notebooks.