The goal is to integrate fuel cells into mobile computers to extend battery life from several hours to up to a couple of days.

This document guides fuel cell developers on what it takes to design fuel cells for all-day computing for mobile PCs, said Kamal Shah, chair of the Mobile PC Extended Battery Life Working Group, which released the guidelines. Shah also is manager of Intel’s mobility enabling initiative.

The document gives companies technical specifics on how to design fuel cells that would be able to power notebook PCs.

A primary consideration is the miniaturization of fuel cells, which need to be small and light to keep pace with the continually shrinking dimensions of notebooks. To operate in the most commonly used location for a secondary power source, the media bay, the fuel cell would need to measure roughly 10mm by 130mm by 130mm, Shah said.

Another major obstacle for fuel cell designers is temperature, since fuel cells currently generate more heat than a notebook could handle.

The guidelines also outline power requirements needed for notebooks, which vary from when a machine is idle to when a user is, say, downloading a graphics file. Now researchers at STMicroelectronics, for instance, can simulate a model of mobile PC power requirements to evaluate fuel cell designs, said Nicola Tricomi, STMicro’s segment marketing manager for industrial and power conversion.

Currently, more than 60 companies are working on direct methanol fuel cell technology for mobile devices, said Jim Balcom, chief executive of PolyFuel Inc.

Initially, fuel cells for notebooks likely would be external and emulate an AC adaptor, Shah said. That is, it would attach to the PC to charge a traditional battery inside. The advantage would be that since the fuel cell generates its own power, it requires no electricity and users could re-charge in a mobile environment.

We believe that over the next several years, solutions will start coming about that will be external to laptop PCs, Shah said.

Fuel cells likely would co-exist with traditional PC batteries for the next five to ten years, he said.

Beyond that, if thermal and miniaturization issues can be solved, there is potential for fuel cells to be integrated into the laptop PC, Shah said.

If fuel cells replaced traditional notebook batteries, then users would be able to re-charge their machines using portable fuel cartridges. Shah said a single small cartridge may provide enough energy to power a machine for a few hours or for a full day, depending on the size of the cartridge and efficiency of the fuel cell.

Exactly what type of fuel would be used has not yet been determined. Fuel cell makers are working on various types of fuel, including concentrated and diluted methanol and sodium borohydride.

For Intel, fuel cells hold the promise of support of its spontaneous mobile computing vision, in which users can compute anything in a mobile environment. Of course, the proliferation of mobile computing would boost demand for Intel chips.

Also included in the documents are references to environmental regulations that fuel cell makers need to adhere to.