Fuel Cell Stack Thermal Control Using Estimated MEA Temperature
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Solution Overview
Problem
Conventional fuel cell systems manage thermal management based on coolant outlet temperature, which does not accurately reflect the temperature of the membrane electrode assembly (MEA), leading to potential performance degradation and overdesign of coolant pumps due to varying MEA temperatures with fuel cell deterioration.
Innovation Solution
A method to estimate MEA temperature using real-time data from output current, voltage, coolant inlet and outlet temperatures, and flow rates, allowing precise thermal management without direct temperature sensors, controlling coolant pump and valve operations based on estimated MEA temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is installed between unit fuel cells to directly measure MEA temperature, then measurement precision is improved, but device complexity and performance degradation occur due to affecting surface pressure and cell pitch
Solution Approach 1:
The patent uses coolant outlet temperature as an intermediary parameter to indirectly estimate MEA temperature. Instead of directly measuring MEA temperature with a sensor, the system measures coolant outlet temperature and uses it as a proxy indicator, avoiding the need to install sensors between unit fuel cells that would compromise stack integrity and performance.
Solution Approach 2:
The patent replaces the mechanical temperature sensor installation approach with a thermal field-based estimation method. By using thermal relationships between coolant temperature and MEA temperature, the system eliminates the need for physical sensor installation that would mechanically interfere with the fuel cell stack assembly.
2Device complexity
If thermal management is performed based on coolant outlet temperature, then device complexity is reduced, but measurement precision deteriorates because coolant outlet temperature does not accurately reflect actual MEA temperature
Solution Approach 1:
The patent establishes a feedback relationship where coolant outlet temperature measurements are continuously used to estimate MEA temperature, which then feeds back into thermal management control decisions. This creates a closed-loop system that adapts cooling strategies based on the estimated MEA temperature derived from coolant temperature feedback.
Solution Approach 2:
The patent transforms the temperature measurement parameter from direct MEA temperature to coolant outlet temperature, and then applies mathematical or empirical relationships to convert this parameter change into accurate MEA temperature estimation, maintaining measurement precision while simplifying the measurement system.
3Reliability
If maximum flow rate of coolant pump is selected based on maximum allowable outlet temperature, then reliability is improved for preventing overheating, but productivity decreases due to overdesign when MEA temperature is actually lower
Solution Approach 1:
The patent implements dynamic coolant pump control where the pump flow rate is adjusted in real-time based on estimated MEA temperature rather than operating at a fixed maximum flow rate. This dynamic adjustment allows the system to maintain reliable overheating protection while optimizing pump efficiency by matching cooling capacity to actual thermal demands.
Solution Approach 2:
The patent applies partial cooling action by adjusting coolant flow rate to match actual thermal needs rather than always applying maximum cooling. When MEA temperature is below maximum allowable levels, the system reduces coolant flow to appropriate levels, avoiding excessive cooling action that would reduce overall system productivity.
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
Accurate MEA temperature estimation prevents performance degradation and overdesign of coolant pumps, effectively protecting the fuel cell stack by adjusting operations to maintain safe temperatures and adapt to deterioration.
Implementation Method 1
A fuel cell is a battery that generates electrical energy by electrochemical reaction between a fuel and an oxidant
Implementation Method 2
low-temperature stack coolant is fed into the fuel cell stack and receives heat generated from the fuel cell stack, increasing the temperature thereof
Implementation Method 3
the stack coolant is discharged from the fuel cell stack, is fed into a radiator, is cooled through the radiator, and then circulates back to the fuel cell stack
Implementation Method 4
the stack coolant is discharged from the fuel cell stack, is fed into a radiator, is cooled through the radiator
Data Source
AI summary
Disclosed is a method of thermal management of a fuel cell system capable of estimating the temperature of a membrane electrode assembly (MEA) of a fuel cell stack based on data that can be collected in real time and performing thermal management of the fuel cell stack based on the estimated temperature of the MEA, the method including determining, by a controller, a heating value and thermal resistance of a fuel cell stack during driving of a vehicle, estimating the temperature of an MEA provided to the fuel cell stack based on the heating value and the thermal resistance of the fuel cell stack, and performing thermal management of the fuel cell stack based on the estimated temperature of the MEA.