Fuel Cell Discharge Controller Prioritizing Load Energy
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Solution Overview
Problem
Conventional fuel cell systems experience significant charge/discharge losses and require a large-scale DC/DC converter when discharging electrical energy, as all discharged energy is routed to the energy storage, leading to inefficiencies and increased converter size and cost.
Innovation Solution
A fuel cell system with a discharge electrical energy controller that prioritizes supplying energy to electrical devices other than the energy storage, allowing the DC/DC converter to operate in a compact, cost-effective manner by only increasing voltage when necessary, and performing the scavenging process in parallel with discharge, reducing losses and converter size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If all discharged electrical energy from the fuel cell is routed to the energy storage, then the energy storage is charged, but charge/discharge losses increase and the DC/DC converter size increases
Solution Approach 1:
The patent extracts the scavenging process from the sequential operation and performs it in parallel with the discharge process. By taking out the scavenging function and executing it simultaneously with discharge, the system avoids the need for large-scale DC/DC converters and reduces charge/discharge losses while maintaining effective water removal from the cathode.
Solution Approach 2:
The patent performs the scavenging process in parallel with the discharge process rather than sequentially. By conducting the scavenging operation concurrently with discharge, the system eliminates the need to store and later discharge energy through the DC/DC converter, thereby reducing converter size and energy losses.
2Reliability
If all discharged electrical energy is charged in the energy storage, then the energy storage voltage is maintained, but the time required to stop the fuel cell system increases
Solution Approach 1:
The patent maintains continuous useful action by performing the scavenging process in parallel with the discharge process. This concurrent operation ensures that water removal continues throughout the discharge phase, preventing water accumulation and enabling faster, more reliable system shutdown without incurring additional charge/discharge losses.
3Device complexity
If the DC/DC converter operates in step up mode to charge the energy storage, then the voltage mismatch is resolved, but the converter size and cost increase
Solution Approach 1:
The patent extracts the voltage conversion function from the DC/DC converter by performing the scavenging process in parallel with discharge. This eliminates the need for the converter to operate in step-up mode, thereby reducing converter size, cost, and switching losses while still achieving effective energy utilization.
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
This approach reduces discharge/charge losses in the energy storage and DC/DC converter, enhances energy efficiency, and shortens the time to stop the fuel cell system after power generation is requested to cease, while maintaining a compact and cost-effective DC/DC converter.
Implementation Method 1
a fuel cell operated for power generation by reaction of reactant gases supplied to the fuel cell
Implementation Method 2
The energy storage is charged with electrical energy supplied from the fuel cell through a DC/DC converter
Data Source
AI summary
When a control device detects a request for stopping power generation of a fuel cell, electrical energy discharged from the fuel cell is supplied to an energy storage and other electrical devices such as an air compressor. At this time, electrical energy is supplied preferentially to the other electrical devices. Accordingly, discharge/charge losses in the energy storage can be reduced, compared to a technique in which an energy storage is charged preferentially at the time of stopping power generation of a fuel cell.