Apparatus and method for fuel cell start from freezing without melting ice

A method of operating a fuel cell system at shutdown under freezing conditions, the method comprising:

• providing a fuel cell stack and an accumulator for receiving water from and supplying water to the fuel cell stack, the accumulator having structure defining a first region having a first volume configured to contain a volume of water during steady state operation of the fuel cell stack and configured to fill with water vertically at a first rate for an arbitrary fill water flow rate, and structure defining a second region having a second volume and configured to fill with water vertically at a second rate greater than said first rate for said same arbitrary fill water flow rate, said first volume of said first region being greater than said second volume of said second region, and the accumulator including a drain in the second region;
• and
• draining water from at least the second region of the accumulator at shutdown to allow the second region to be substantially water and ice-free upon shutdown, whereby said second region of the accumulator may receive water from and supply water to the fuel cell stack upon start up.