Coolant purification
A fuel cell system comprising a fuel cell stack is disclosed. An ozone generator is configured to introduce ozone into a coolant in the fuel cell system. A deionization apparatus is coupled to the fuel cell stack. A bypass conduit is arranged in parallel with the deionization apparatus. A controller is configured to control flow of the coolant to the fuel cell stack through either the deionization apparatus or the bypass conduit based on the operating state of the ozone generator.
1. A fuel cell system comprising:
a fuel cell stack;
an ozone generator configured to introduce ozone into a coolant in the fuel cell system;
a deionisation apparatus coupled to the fuel cell stack;
a bypass conduit arranged in parallel with the deionisation apparatus; and,
a controller configured to control flow of the coolant to the fuel cell stack through either the deionisation apparatus or the bypass conduit based on the operating state of the ozone generator; and,
wherein the controller is configured such that coolant passes through the bypass conduit when a level of ozone in the coolant is determined to be above a predetermined threshold, and such that coolant passes through the deionisation apparatus when the level of ozone in the coolant is determined to be below a predetermined threshold.
2. A fuel cell system comprising:
a fuel cell stack;
an ozone generator configured to introduce ozone into a coolant in the fuel cell system;
a deionisation apparatus coupled to the fuel cell stack;
a bypass conduit arranged in parallel with the deionisation apparatus; and,
a controller configured to control flow of the coolant to the fuel cell stack through either the deionisation apparatus or the bypass conduit based on the operating state of the ozone generator, wherein the controller is configured to control the coolant flow to the fuel cell stack such that:
the coolant passes through the bypass conduit during;
an ozone generation period, during which the ozone generator introduces ozone into the coolant; and,
an ozone decomposition period.
3. The fuel cell system of claim 2 , such that the controller is configured to control the coolant flow to the fuel cell stack such that coolant passes through the deionisation apparatus outside the ozone generation period and the ozone decomposition period.
4. The fuel cell system of claim 2 , wherein the ozone decomposition period is a period of time during which ozone in the coolant decomposes to a level of ozone below a threshold level.
5. The fuel cell system of claim 2 , wherein the ozone decomposition period is determined from the duration of the ozone generation period.
6. The fuel cell system of claim 1 , wherein the controller is configured to control the coolant flow to the fuel cell stack by controlling the position of a valve to direct coolant either through the deionisation apparatus or through the bypass conduit.
7. The fuel cell system of claim 1 , comprising a coolant reservoir coupled to the fuel cell stack via the deionisation apparatus and bypass conduit, the coolant reservoir configured to receive coolant containing ozone.
8. The fuel cell system of claim 1 , wherein the controller is configured to cause an ozone generator to periodically introduce ozone in the coolant.
9. The fuel cell system of claim 1 , wherein the controller is configured to cause the ozone generator to dynamically introduce ozone in the coolant based on one or more of:
a level of bacteria in the coolant;
a coolant level;
a coolant temperature;
a coolant pressure;
a fuel cell stack operating parameter;
a stack voltage;
a level of fuel in the fuel cell system; and,
a level of oxidant in the fuel cell system.
10. The fuel cell system of claim 1 , wherein the coolant is water.
11. The fuel cell system of claim 1 , wherein the controller is configured to control the coolant flow to the fuel cell stack by controlling the position of a non-return valve positioned between the deionisation apparatus and the fuel cell stack to prevent the flow of coolant from the fuel cell stack passing through the deionization apparatus.
12. The fuel cell system of claim 1 , wherein the controller is configured to control the coolant flow to the fuel cell stack by controlling the position of a non-return valve positioned between the bypass conduit and the fuel cell stack to prevent the flow of coolant from the fuel cell stack passing through the bypass conduit.
13. The fuel cell system of claim 1 , wherein the fuel cell system comprises an ultra violet light source configured to illuminate coolant before the coolant reaches the fuel cell stack.
14. A vehicle comprising the fuel cell system of claim 1 .