End Cell Heater Assembly for Fuel Cell Cold Start
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Solution Overview
Problem
Fuel cell stacks experience performance deterioration and delayed cold start due to heat loss and frozen water blocking gas flow in end cells, leading to inefficient electric power generation and prolonged start times.
Innovation Solution
An end cell heater assembly is integrated into the fuel cell stack, using a planar heating element and bypass flow paths to distribute reactant gases and provide direct heating to end cells, reducing heat loss and improving gas distribution, thereby accelerating the cold start process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If end cells are positioned at both ends of the fuel cell stack, then the stack structure is simplified and compact, but heat loss increases and cold start performance deteriorates
Solution Approach 1:
The heating element is activated before the fuel cell stack is started (cold start condition) to preheat the end cells. This preliminary heating action raises the temperature of end cells to a level where the membrane can properly function, preventing the performance deterioration that would otherwise occur during cold start conditions.
Solution Approach 2:
The heating element is specifically positioned at the end cells rather than uniformly heating the entire stack. This localized heating approach addresses the specific heat loss problem at the ends of the stack without unnecessarily heating the central cells, thereby resolving the temperature issue at end cells while maintaining overall structural simplicity.
2Loss of time
If heating is applied to end cells during cold start, then cold start time is reduced, but energy consumption increases
Solution Approach 1:
The heating element is positioned only at the end cells where heat loss occurs, rather than heating the entire stack. This localized approach reduces the total energy required for heating while still achieving the goal of reducing cold start time by preventing performance deterioration at the critical end cell locations.
Solution Approach 2:
The heating element is activated only during the cold start phase before the fuel cell begins normal operation. Once the fuel cell generates sufficient power and temperature, the heating element is deactivated. This time-limited preliminary heating action reduces cold start time while minimizing overall energy consumption.
3Power
If reactant gases are supplied to end cells, then power generation is maximized, but frozen water blocks gas flow and deteriorates performance
Solution Approach 1:
The heating element is activated before reactant gases are supplied to the end cells during cold start conditions. This preliminary heating raises the temperature of the end cells above the freezing point, ensuring that water produced during operation remains in liquid form and does not block gas flow paths, thereby maintaining reliable gas flow and power generation.
Solution Approach 2:
The heating element applies heat in advance to prevent the formation of frozen water that would block gas flow. By maintaining the temperature above freezing before and during gas supply, the system prevents the harmful effect of ice formation, ensuring continuous reliable gas flow and power generation at the end cells.
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 end cell heater assembly increases end cell temperature, enhances reactant gas distribution, prevents voltage drops, and improves cold start efficiency by melting frozen moisture quickly, thus reducing start time and maintaining power generation efficiency.
Implementation Method 1
a planar heating element installed in an accommodating groove formed in a second surface of the case
Implementation Method 2
joined and electrically connected to the end cell, and transferring heat generated by the planar heating element to the end cell
Implementation Method 3
has a bypass flow path so that at least one gas of air and hydrogen supplied to the fuel cell stack as reactant gases is distributed to and passes through the bypass flow path
Implementation Method 4
improving cold start efficiency by melting frozen moisture quickly
Data Source
AI summary
An end cell heater assembly includes: a case which has a first surface joined to an end plate of a fuel cell stack; a planar heating element installed in an accommodating groove formed in a second surface of the case; a terminal plate which is stacked and interposed between the planar heating element and an end cell of the fuel cell stack, joined and electrically connected to the end cell, and transferring heat generated by the planar heating element to the end cell; and a terminal which is integrally formed with the terminal plate so as to output electrical energy generated by the fuel cell stack and transferred through the terminal plate, to the outside.