Fuel Cells – Now for Portable Devices
In the past fuel cell advocates focused on large stationary applications (home, commercial buildings, etc.) due to the size and weight of the fuel cell. Today, portable applications are targeted. There are two types of fuel cells – proton exchange membrane, and direct methanol. In the proton exchange membrane method, a thin membrane forms a barrier that contains the electrical flow but provides excess protons to support charge transfer. In the Direct Methanol method, methanol is fed to the anode as fuel which simplifies the overall design of the fuel cell.
The key issue in bringing fuel cells to the portable market is cost. While the technology is available, the price of a fuel cell for a handheld device must be competitive to batteries. A number of companies are starting to achieve that price point.
Ultracell using a reformed methanol system offers a portable fuel cell that can power a laptop for several days at 25W. Called the XX25, they recently received funding from the US Army CERDEC program. The XX25 is 75% lighter than comparable batteries.
MTI MicroFuel Cells now sells a Direct Methanol Fuel cell to replace Lithium-ion batteries increasing device usage times by 2x to 10x.
Medis Technologies uses a special blend of chemicals including borohydride to achieve a longer lasting fuel cell.
This article indicates it won’t be too long before fuel cells are incorporated into portable devices rather than simply powering them.
Computer vendors are also starting to implement fuel cells in their laptops. Panasonic showed a laptop powered by a fuel cell at the CES show earlier this year.
Fuel cells will be slightly different from batteries in their usage. With a rechargeable battery, one plugs the battery into a recharger and then waits. With portable fuel cells, one will buy replacement cartridges (containing the fuel) and plugging it in without waiting for recharging as with batteries. Given this method of operation, fuel cells will compete with rechargeable batteries and not use-once batteries since the cost is much lower.
Other issues remain with portable fuel cells. The methanol fuel inside the fuel cell is flammable which exposes the user to some risk of burn and taking flammable substances on board an aircraft is also problematic. Some predict fuel cells will perform as a battery backup system rather than the primary electrical source for portable devices. This technology isn’t coming too soon – my laptop battery is about to run out.