Fuel Cell System COD Heater Control for Battery and Efficiency
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Solution Overview
Problem
Fuel cell systems face challenges in efficiently managing energy consumption during cold starts and downhill driving, leading to potential battery overcharging, brake intervention, and reduced fuel efficiency, due to inadequate control of the COD heater and regenerative braking.
Innovation Solution
A fuel cell system with a controller that manages the COD heater's operation based on battery state of charge and regenerative power, ensuring efficient energy consumption and preventing brake intervention by predicting downhill driving and adjusting the COD heater's output to maintain optimal battery levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the COD heater is operated to consume regenerative braking energy during downhill driving, then the battery state of charge is maintained and regenerative braking can continue, but the fuel cell stack may be excessively operated reducing overall fuel efficiency
Solution Approach 1:
The controller continuously monitors the state of charge of the battery and the output of the fuel cell stack, and dynamically adjusts the operation of the COD heater based on this feedback. This feedback mechanism ensures that the COD heater operates only when necessary to maintain battery charge levels, avoiding unnecessary consumption of regenerative braking energy and preserving fuel efficiency.
Solution Approach 2:
The system dynamically adjusts the operation mode of the COD heater based on real-time conditions. The controller switches between different operating states (heating mode, energy consumption mode, or standby mode) depending on the battery state of charge and fuel cell output, optimizing the balance between maintaining regenerative braking capability and preserving fuel efficiency.
2Reliability
If the COD heater is operated during downhill driving to consume regenerative energy, then battery overcharging is prevented, but the hydraulic brake may still intervene reducing product quality
Solution Approach 1:
The controller predicts downhill driving conditions in advance and proactively manages the battery charge level by controlling the COD heater operation before the downhill segment begins. This preliminary action ensures that the battery is in an optimal charge state to absorb regenerative braking energy, preventing both overcharging and the need for hydraulic brake intervention during the downhill drive.
Solution Approach 2:
The system uses continuous feedback from battery state of charge sensors and fuel cell output monitors to adjust COD heater operation in real-time. This feedback loop ensures that the battery charge level is maintained within optimal ranges, preventing overcharging while ensuring sufficient capacity to absorb regenerative braking energy and avoid hydraulic brake intervention.
3Use of energy by moving object
If the fuel cell stack is turned off when no power generation is required after cold start, then energy consumption is reduced, but the durability of the fuel cell stack deteriorates
Solution Approach 1:
The system maintains continuous low-level operation of the fuel cell stack through controlled consumption of its generated energy by the COD heater. This continuous useful action prevents the stack from being completely shut down, maintaining operational readiness and preventing durability deterioration while still managing energy consumption efficiently.
Solution Approach 2:
The fuel cell stack serves its own durability needs by having its generated energy consumed by the COD heater. This self-service mechanism allows the stack to remain operational at minimal levels without requiring external power demands, thereby maintaining durability while minimizing overall energy consumption of the vehicle system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces cold start times, prevents battery overcharging, maintains regenerative braking, and improves fuel efficiency by strategically controlling the COD heater's operation in response to battery state and regenerative power generation.
Implementation Method 1
a radiator configured to exchange heat with coolant discharged from a fuel cell stack
Implementation Method 2
a COD heater configured to consume electric power generated by the fuel cell stack
Data Source
AI summary
Described herein is a fuel cell system that includes a radiator configured to exchange heat with coolant discharged from a fuel cell stack, a coolant supply pump configured to supply the coolant to the fuel cell stack, a COD heater configured to consume electric power generated by the fuel cell stack, a valve connected to the fuel cell stack, the radiator, the coolant supply pump, and the COD heater to control a flow of the coolant, and a controller configured to control an operating start time and output of the COD heater to consume energy generated by the fuel cell stack depending on a state of charge (SOC) of a battery and an operating state of the fuel cell stack. The controller controls the valve so that the coolant flows to the COD heater in a temperature control section after a cold start section of the fuel cell stack.