Fuel Cell Stack with Conductive Middle Plates for Hybrid Power Systems
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Solution Overview
Problem
Current hybrid power systems combining fuel cells and batteries face inefficiencies due to mismatched dynamic behaviors, leading to compromised performance and increased stress on one power source, with existing solutions like DC/DC step-up converters being inefficient and costly, and previous patents proposing complex modifications that are not cost-effective.
Innovation Solution
A hybrid power system that includes a fuel cell stack with conductive middle plates and a control unit to select operating voltages based on battery and fuel cell stack voltages, allowing for optimized power delivery and reduced stress on the fuel cell, using a simpler and cost-effective configuration that avoids the need for complex power management systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a DC/DC step-up converter is used to match voltages between battery and fuel cell, then voltage compatibility is improved, but system efficiency decreases and heat dissipation increases
Solution Approach 1:
The patent extracts the voltage matching function from the power management system by directly utilizing the fuel cell stack's intermediate voltage nodes. This eliminates the need for external DC/DC step-up converters, thereby removing the associated energy losses and heat dissipation issues while maintaining voltage compatibility between battery and fuel cell.
Solution Approach 2:
The patent introduces intermediate voltage nodes within the fuel cell stack as mediators for voltage matching. These intermediate nodes serve as natural voltage transition points that enable direct connection between battery and fuel cell at compatible voltage levels, eliminating the need for active voltage conversion and its associated inefficiencies.
2Loss of energy
If electronic switching is used between batteries and fuel cells, then system efficiency is improved, but both power sources cannot deliver power simultaneously
Solution Approach 1:
The patent segments the fuel cell stack into multiple sub-stacks with distinct voltage nodes, enabling independent access to different voltage levels. This segmentation allows the system to simultaneously utilize both battery and fuel cell power sources by connecting them at appropriate voltage nodes, thereby maintaining high efficiency while enabling flexible power delivery configurations.
3Power
If battery delivers high current, then power demand is met, but battery capacity depletes faster
Solution Approach 1:
The patent enables preliminary action by allowing the fuel cell to operate independently or in parallel with the battery before the battery is fully depleted. This preliminary engagement of the fuel cell reduces the overall discharge burden on the battery, extending its effective capacity and duration of action while still meeting high power demands when needed.
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 enables the fuel cell to operate within its maximum efficiency range, extending its lifespan, reducing maintenance costs, and providing more power without overheating, while allowing the battery to deplete fully while the fuel cell contributes, thus achieving optimized hybrid power delivery.
Implementation Method 1
a fuel cell stack with one or more middle conductive plates to tap the fuel cell stack at an intermediate voltage
Implementation Method 2
The control unit is configured to select an operating voltage of the fuel cell stack... depending on the values of the voltages at the contact terminals of the fuel cell stack and the voltage of the battery
Data Source
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AI summary
A fuel cell stack for enhanced hybrid power systems, comprising first (2) and second (3) conductive end plates with contact terminals (4); a plurality of fuel cells (7) configured to be connected in series and stacked between the conductive end plates (2, 3); at least one conductive middle plate (6, 6') with at least one contact terminal (11, 11'), each conductive middle plate (6, 6') being configured to be stacked between adjacent fuel cells (7). The contact terminals (11, 11') may comprise conductive tabs (11) protruding from the fuel cell stack (1). The invention also refers to a hybrid power system comprising a battery (50), a fuel cell stack (1) and a control unit (70) configured to select an operating voltage of the fuel cell stack (1) when the hybrid power system (90) is feeding a load (60). The operating voltage is obtained from the contact terminals (4, 11, 11') of the conductive middle plate (6, 6') and conductive end plates (2, 3) depending on the values of the voltages (V1, V2, V3) at the contact terminals (4, 11, 11') of the fuel cell stack (1).