Temperature Control for Fuel Cell Systems

Fuel cell vehicle thermal management system that allows low-temperature rapid preheating and precise temperature control of both the fuel cell and battery packs using a common coolant loop. The system has separate coolant circuits for the fuel cell stack and battery pack, with a common expansion pot and pump. A three-way solenoid valve allows selective circulation between the stack and battery circuits. This allows preheating the battery when the stack is warm, and vice versa. A single intercooler cools both circuits. The stack coolant inlet temperature sensor regulates the stack heating, and the battery coolant inlet sensor regulates the battery heating.

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Fuel cell temperature control system and method that improves fuel cell efficiency during cold starts and idle operation. The system uses a thermostat, water heater, and solenoid valve to control the flow of coolant between heating and cooling circuits. During cold starts, a small coolant loop heats the fuel cell stack. Once the stack temperature is high enough, the thermostat opens fully to circulate coolant through both loops. This prevents sudden temperature drops when switching to full circulation. During idle, the thermostat increases in small steps to balance heating and cooling. A solenoid valve can bypass the thermostat during cold starts to fully heat the stack. The method involves starting the pump, waiting, checking stack temperature, then gradually opening the thermostat.

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Active thermal management system for fuel cell stacks that improves performance and durability by dynamically controlling coolant flow to each cell based on measured temperature distribution. The system has a coolant distribution device in the manifold that can open/close to steer coolant flow between cell groups based on temperature readings. This reduces temperature variation across cells and prevents overcooling or overheating issues.

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Fuel cell system that allows more efficient and autonomous cooling control when specific fuel cell conditions are met. The fuel cell controller can override upper-level controller instructions and independently control the fuel cell cooler in a predetermined sequence when certain fuel cell conditions are satisfied. This allows unique fuel cell-specific cooling needs to be handled locally by the fuel cell controller instead of requiring the upper-level controller to understand and implement those cooling requirements.

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A fuel cell system that allows faster cold start and enables immediate driving away in cold weather. It uses the fuel cell inverter to actively heat the fuel cell stack during cold starts instead of relying solely on external heaters. When the stack temperature is low, the inverter switches to a configuration where it draws power from the fuel cell to generate heat internally. This heat is then transferred to the stack to quickly bring it up to operating temperature. Once warm, the inverter switches back to normal mode and the fuel cell powers the vehicle. This avoids the need for external heaters and allows immediate driving away.

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Fuel cell system that can maintain stack temperature and improve durability in abnormal operating conditions, manage multiple fuel cell modules, and use a complex reformer without separate water treatment. The system has a temperature maintenance unit to keep stack temperature during power outages or fuel cuts. It also has a module management unit to set standby mode for modules based on power demand. The complex reformer has a fuel control to adjust steam and partial oxidation reformer based on anode exhaust water vapor.

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Fuel cell heat dissipation system that reduces complexity and cost compared to conventional systems with separate main and auxiliary radiators. The system has a single dual-core radiator with isolated water channels and connected air paths. The main heat dissipation circuit uses the main core and the auxiliary circuit uses the auxiliary core. This allows sharing of the main radiator for both circuits. The fan is on the main core side. The system also has integrated water tanks and pumps for each circuit. A control method regulates fan and pump speeds based on temperatures to balance cooling.

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Hot module for a fuel cell system that allows easy temperature control of the fuel cell stack. The hot module has a cooling body near the stack where cooling air flows through to extract heat. By adjusting the air flow rate, excess heat inside the module can be discharged to maintain stack temperature. This eliminates the need for external cooling and prevents stack overheating. The cooling body is positioned near the stack and configured with the same air flow direction as the stack fuel flow. It can have turbulent flow features and shapes like boxes or tubes.

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Fuel cell cold start device using phase change material to enable reliable low temperature starting of fuel cells without preheating. The device consists of a heat storage unit filled with a phase change material, a water pump, fuel cell stack, three-way valve, radiator, temperature sensors, and a controller. During startup, the pump circulates coolant through the heat storage to melt the phase change material. This provides heat to the fuel cell stack to prevent ice formation. After startup, the valve switches to bypass the heat storage and use the radiator for cooling. The controller monitors temperatures to manage the heating and cooling cycles.

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A fuel cell water and heat management system with improved temperature control for different operating conditions. The system has multiple heat exchangers connected in parallel with a three-way and four-way valve. This allows separate heat dissipation branches for the first and second radiators, heater, and intercooler. The valves can be selectively actuated to route cooling water through the appropriate branches based on fuel cell temperature. This provides more granular temperature control compared to simple warm-up and cool-down modes.

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Reducing warm-up time of a fuel cell system by efficiently raising the cooling water temperature during startup. During warm-up, instead of just using fuel cell power to heat the coolant, a separate power consumption unit like a brake resistor also draws power. This increases the total heat generation to raise coolant temp faster. The system detects coolant temperature and switches between optimized warm-up methods based on starting conditions. If coolant is very low, use the dual heat source method. If coolant is warmer, use the single heat source method.

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A thermal management system for fuel cells that provides rapid and dynamic temperature control to improve fuel cell performance and reliability. The system uses a heat exchange module with a multi-pass structure that allows adjusting the cooling flow rate based on stack power demand. It connects the stack, stack outlet, and heat exchanger in a main cooling loop, with a separate circulation loop that mixes coolant from both circuits. This provides quicker stack temperature response compared to radiators, preventing excessive cooling. An intercooler further reduces stack temperature. The circulation pump powers the mixed coolant loop.

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Reducing the number of heaters in fuel cell power systems to save costs and energy compared to conventional designs. The idea is to use a master fuel cell with built-in heaters to warm up and start, then transfer heat to a slave fuel cell instead of using heaters on both cells. A controller switches between loops based on start conditions. This reduces the number of heaters needed compared to independent heating for each cell.

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Thermal management system for fuel cell vehicles that allows efficient cooling of fuel cell stacks, electric motors, and batteries without increasing vehicle drag. The system has a hierarchical thermal circuit with a backbone ambient loop and dedicated loops for fuel cells, motors, and batteries. The backbone loop provides primary cooling to the others. This allows efficient cooling without adding radiators to the front end. The system also has features like PTC heaters, compressor-based refrigeration, and bypass valves for optimized cooling in different conditions.

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A fuel cell system for vehicles that improves cooling and power generation performance of the fuel cells while preventing temperature overshoot. The system uses a fuel cell stack, temperature sensor, cooling fan, and control circuit. The control circuit sets higher target temperatures for the fuel cell stack when more power is needed. It suppresses fan speed changes until the actual temperature reaches the target. This prevents supercooling and allows faster temperature rise. Feedback control adjusts fan speed based on target temp, and feedforward control based on heat release. This improves fan speed control. The system uses multiple stages for power and temp targets to reduce voltage fluctuations.

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A fuel cell system that can quickly warm up a fuel cell to the operating temperature without using refrigerant, thereby avoiding heat spots that degrade fuel cell performance. During warm-up when the fuel cell temperature is below the target, the system stops refrigerant supply and increases the oxidant gas flow rate. This cools the fuel cell using the oxidant instead of refrigerant. The oxidant flow rate is controlled to raise the fuel cell temperature to the target. This allows faster warm-up without heat spots compared to using no oxidant or adjusting refrigerant flow.

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Fuel cell thermal management system that integrates fuel cell cooling, passenger cabin heating, and deionization into a single system. The system uses independent pipelines for cooling and heating to avoid waste heat loss. It also has an on-demand deionizer to prevent ion buildup in the coolant. The control is a combination of feedforward and feedback that adaptively tunes parameters based on working conditions to reduce overshoot. This improves efficiency, reduces waste, and enables more flexible layout of heating components.

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Fuel cell system with optimized water management and coking prevention to enable operation of intermediate temperature solid oxide fuel cells (IT-SOFC) at high efficiency. The system uses a heat exchanger to cool the anode off-gas and heat a transfer fluid. The transfer fluid is then reheated by another exchanger before returning to the first exchanger. A pump circulates the fluid. The key is controlling the pump speed versus flow rate of another medium to balance cooling and reheating. This prevents freezing and coking issues. By prioritizing pump speed over other flow, heat is added to the fluid. Conversely, lower pump speed with reduced other flow removes heat. This allows high anode off-gas cooling without condensate freeze risk.

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Flexibly cooling a fuel cell stack based on its output current and temperature to improve efficiency and lifespan. The cooling air supply is controlled in addition to the stack temperature to stabilize output current. If the stack temperature rises, cooling air flow is increased. If output current decreases, cooling air flow is reduced. This allows cooling to adapt to stack state rather than fixed levels. It prevents excessive cooling causing dew point issues, or insufficient cooling leading to overheating. By dynamically managing cooling based on stack conditions, the fuel cell stack can operate more effectively and reliably over its lifetime.

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Efficiently heating or cooling a battery in a fuel cell system using the waste heat from the fuel cell. The system has two fluid circuits, one connected to the fuel cell and the other to the battery, that can be reversibly thermally coupled together. By selectively connecting the circuits, excess fuel cell heat can be used to bring the battery temperature into an optimal range without extra power consumption. A heat exchanger allows indirect thermal coupling to maintain separate fluid flows. The circuits are thermally decoupled when the fuel cell has enough heat or the battery is already warm enough.

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