Freeze prevention of a fuel cell power plant
AssigneeNissan Motor Co., Ltd.
InventorShinichi Takahashi
Life of this patent
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Abstract
A fuel cell power plant comprises a water circulation passage (5) which circulates the cooling water in a fuel cell stack (4). Sodium hydroxide which lowers the melting point of water is mixed with water in the water circulation passage (5) to prevent freezing of the water in the water circulation passage (5). Electrodes (11, 12) are disposed in the water. When the fuel cell stack (4) is running, a voltage is applied between the electrodes (11, 12) such that the positive electrode (11) attracts sodium ions, thereby removing sodium ions from the cooling water supplied to the fuel cell stack (4). When the fuel cell stack (4) stops running, sodium ions which were attracted to the positive electrode (11) are made to diffuse into the cooling water by ceasing to apply the voltage to the electrodes (11, 12).
Claims15
An antifreeze apparatus comprising:
- a fuel cell stack;
- a water circulation passage circulating water and antifreeze through the fuel cell stack;
- an antifreeze release/recovery mechanism functioning to release antifreeze into the water in the water circulation passage upstream of the fuel cell stack and recover and store or collect antifreeze from the water in the water circulation passage downstream of the fuel cell stack;
- a sensor which detects whether or not the fuel cell stack is operating;
- and
- a programmable controller programmed to;
- control the release/recovery mechanism to release antifreeze into the water in the water circulation passage when the fuel cell stack is not operating;
- and
- control the release/recovery mechanism to recover and store or collect antifreeze which has diffused into the water in the water circulation passage when the fuel cell stack is operating.
An antifreeze apparatus comprising:
- a fuel cell stack;
- a water circulation passage circulating water and antifreeze through the fuel cell stack;
- an antifreeze release/recovery mechanism functioning to release antifreeze into the water circulation passage when a water temperature of the water circulation passage is not higher than a predetermined temperature, and recover and store or collect antifreeze in the water circulation passage when the water temperature of the water circulation passage is higher than the predetermined temperature, wherein the antifreeze release/recovery mechanism comprises a molecular matrix aggregate of a polymer material which expands when the water temperature is not higher than the predetermined temperature, and contracts when the water temperature is higher than the predetermined temperature, the water circulation passage being arranged to pass through the aggregate.
An antifreeze apparatus comprising:
- a fuel cell stack;
- a water circulation passage for circulating water and antifreeze through the fuel cell stack;
- an antifreeze release/recovery mechanism functioning to release antifreeze into the water in the water circulation passage upstream of the fuel cell stack and recover and store or collect antifreeze from the water in the water circulation passage downstream of the fuel cell stack;
- means for detecting whether or not the fuel cell stack is operating;
- means for controlling the antifreeze release/recovery means to release the antifreeze into the water in the water circulation passage when the fuel cell stack is not operating;
- and
- means for controlling the antifreeze release/recovery means to recover and store or collect antifreeze which has diffused into the water in the water circulation passage when the fuel cell stack is operating.
Dependencies are inferred from the claim text.