Parallel Fuel Cell Air Compression Layout With Balanced Axial Forces
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Solution Overview
Problem
Conventional fuel cell systems require numerous complex and expensive components, particularly in air supply and power electronics, leading to inefficiencies and high costs, especially when used in parallel configurations for larger systems like commercial vehicles.
Innovation Solution
A fuel cell facility with two parallel fuel cell systems utilizing a two-stage air conveying device with symmetrically arranged compressor wheels and electric machines, eliminating the need for expensive DC/DC converters and simplifying axial bearings, while incorporating exhaust gas recirculation and humidification to optimize air supply and reduce component redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If two individual fuel cell systems are used in parallel to supply power for larger systems, then the required power can be provided, but the number of components doubles leading to increased complexity and cost
Solution Approach 1:
The patent merges two individual fuel cell systems by combining their air supply components into a single common air conveying device. The two compressor wheels are integrated onto one shaft, and a single turbine handles exhaust from both stacks. This merging eliminates redundant components while maintaining the dual-stack power generation capability, directly resolving the contradiction between providing sufficient power and reducing component complexity.
Solution Approach 2:
The common air conveying device serves both fuel cell stacks simultaneously, making it a universal component that performs the air supply function for multiple systems. The single turbine recovers energy from exhaust of both stacks, and the unified control system manages both fuel cell systems, demonstrating multi-functionality that reduces overall system complexity while maintaining required power output.
2Loss of energy
If electric turbochargers are used for air supply in fuel cell systems, then power can be recovered via turbine, but the load on axial bearings becomes high due to force ratio between turbine and compressor wheels
Solution Approach 1:
The patent positions the two compressor wheels symmetrically on opposite sides of the turbine on the same shaft. This symmetric arrangement creates counterbalancing forces where the axial forces from one compressor wheel offset the forces from the other, significantly reducing the net axial load on the bearings. This counterbalancing effect maintains power recovery efficiency while solving the bearing load problem.
Solution Approach 2:
While the overall arrangement is symmetric for force balance, the patent allows asymmetric operation where one compressor wheel can be adjusted or disconnected to optimize performance under different operating conditions. This provides flexibility to manage force distribution and bearing loads dynamically while maintaining efficient power recovery when both wheels operate.
3Ease of operation
If flow compressors are used to provide desired ratio of volume flow to pressure, then air supply can be controlled, but already compressed air must be blown off to achieve desired ratio reducing overall efficiency
Solution Approach 1:
The patent employs dynamic control of the common air conveying device where the compressor and turbine speeds can be independently adjusted based on real-time operating conditions. This dynamic adjustment allows the system to maintain the optimal volume flow to pressure ratio without wasting compressed air, as the system can adapt continuously rather than requiring blow-off operations.
Solution Approach 2:
The system incorporates feedback control mechanisms that monitor air supply conditions and adjust compressor/turbine operation accordingly. This feedback loop ensures that compressed air is utilized efficiently by adjusting operating parameters to match demand, eliminating the need to blow off already compressed air while maintaining precise control over the volume flow to pressure ratio.
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 configuration enhances efficiency, reduces component complexity and cost, and allows for flexible operation by minimizing friction and axial forces, enabling efficient power distribution and extended system lifespan with reduced power electronics requirements.
Implementation Method 1
Both stages are implemented in the form of flow compressors, which each have one compressor wheel per stage
Implementation Method 2
electric turbochargers... which include a compressor wheel on one side and a turbine on the other side
Implementation Method 3
The compressor wheels for one and the other fuel cell system are arranged symmetrically in relation to at least one electrical machine on a shaft
Data Source
AI summary
The invention relates to a fuel cell facility (1) having two parallel fuel cell systems (13, 14), each of which comprises at least one fuel cell stack (15, 16, 17, 18) having anode-side and cathode-side periphery, and having a common air conveying device (2), The fuel cell facility (1) according to the invention is characterized in that the air conveying device (2) is designed in two stages, wherein both stages are designed in the form of flow compressors (3, 4) which each have one compressor wheel (8, 9, 10, 11) per stage, wherein the compressor wheels (8, 9; 10, 11) for the one and the other fuel cell system (13; 14) are arranged symmetrically to at least one electrical machine (5, 6) on a shaft (7).