Fuel Cell Sub-Stack Heating Using Intermediate Plate Valving
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Solution Overview
Problem
Fuel cells require separate heating and cooling devices, increasing mass and space requirements, and energy consumption, with preheating using electrical resistance consuming significant energy and mass.
Innovation Solution
A fuel cell system with intermediate plates that allow for the formation of sub-stacks, enabling heat transfer fluid circulation for both heating and cooling, and using energy generated by operational sub-stacks to preheat other sub-stacks, reducing overall energy requirements and maintaining optimal temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If separate heating and cooling devices are used, then temperature regulation is achieved, but mass and space requirements increase significantly
Solution Approach 1:
The patent combines heating and cooling functions into a single integrated device. The same physical infrastructure (housing, fluid circulation system) is used for both heating mode (with resistance heater) and cooling mode (with pump and heat exchanger), eliminating the need for separate dedicated devices and reducing overall mass and space requirements.
Solution Approach 2:
The integrated device performs multiple functions: it can heat the fuel cell using either a resistance heater or exothermic reaction, and it can cool the fuel cell using a pump-driven circulation system. The control unit switches between these functions based on temperature requirements, making the device universal and eliminating the need for separate specialized equipment.
2Temperature
If separate heating and cooling devices are used, then temperature regulation is achieved, but energy consumption increases
Solution Approach 1:
The patent utilizes the exothermic reaction (normally a source of heat that needs management) as a beneficial heating source. The heat generated by the exothermic reaction between the fuel cell and the heating material is captured and used to warm the fuel cell, converting what would be waste heat into useful thermal energy for startup and temperature maintenance.
Solution Approach 2:
The system uses its own generated heat from the exothermic reaction to preheat and maintain the fuel cell temperature, reducing the need for external energy input. The integrated design allows the system to self-regulate temperature using internal resources rather than continuously consuming external energy.
3Speed
If electrical resistance preheating is used, then the fuel cell reaches operating temperature quickly, but significant energy and mass are consumed
Solution Approach 1:
The exothermic reaction provides rapid heating without continuous external energy input. The chemical reaction between the fuel cell components and heating material generates intense heat quickly, achieving fast preheating similar to electrical resistance heating but with sustained thermal energy from the reaction itself rather than continuous electrical power consumption.
Solution Approach 2:
The system changes the heating mechanism from electrical energy conversion to chemical energy release. By using an exothermic chemical reaction instead of electrical resistance heating, the system achieves rapid temperature increase while fundamentally changing the energy source parameters, thereby reducing ongoing energy consumption and eliminating the need for large battery capacity.
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 energy needed for preheating, allows for efficient temperature maintenance, and enables quick regeneration of power by maintaining part of the stack at working temperature, improving power generation efficiency and reducing mass and space requirements.
Implementation Method 1
ducts for circulating a heat transfer fluid, an oxidant and a fuel in the fuel cell
Implementation Method 2
circulation of the heat transfer fluid, the oxidant and the fuel
Implementation Method 3
the electrochemical reaction taking place within each elementary fuel cell is an exothermic reaction
Implementation Method 4
This preheating can be carried out by means of an electrical resistance which is powered by a battery
Data Source
AI summary
Fuel cell including a stack of membrane/electrodes assemblies, an inlet end plate and an outlet end plate, n intermediate plates disposed in the stack between the inlet and outlet end plates to form n+1 sub-stacks of the stack, n being greater than or equal to 1. The fuel cell may include ducts for circulating a heat transfer fluid, an oxidant and a fuel passing in the inlet and outlet end plates and the n intermediate plates, valves that may control the heat transfer fluid in the circulation ducts, and valves that may control the heat transfer fluid, the oxidant, and the fuel in the circulation ducts of the n intermediate plates and may be configured to allow circulation of the heat transfer fluid, the oxidant, and the fuel in m sub-stacks of the stack, m being greater than or equal to 1 and less than or equal to n.