Fuel Cell Coolant Injection Controller for Freezing Startup
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Solution Overview
Problem
Fuel cell systems face challenges in starting up and operating efficiently in sub-zero conditions due to frozen coolant in the water storage tank, which can lead to blockages and insufficient hydration and cooling, potentially preventing the system from restarting or operating at full power until the frozen water is thawed, and existing solutions rely on limited battery power for heating.
Innovation Solution
A method involving a two-phase operation for the fuel cell system, where the first phase generates power to heat frozen coolant in the coolant storage module, and the second phase delivers heated coolant to the fuel cell assembly, allowing the system to thaw and maintain coolant in a usable state, with optional heater elements and controlled fuel and oxidant flow rates to optimize power output and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heater is provided in the fuel cell system to maintain above-zero temperatures and prevent freezing, then the reliability of coolant supply is improved, but the device complexity increases and the heater may fail when battery power is limited or discharged
Solution Approach 1:
The fuel cell assembly generates its own power to operate the heater element, eliminating dependence on external battery power. The system serves itself by using its generated electrical energy to prevent freezing of the coolant in the storage tank, thereby maintaining operational reliability without adding complex external power dependency.
Solution Approach 2:
The heater element is activated during the first phase of operation to preemptively thaw frozen coolant before it is needed for cooling. This preliminary heating action ensures that liquid coolant is available when the fuel cell assembly begins normal operation, preventing startup failures due to frozen coolant.
2Productivity
If the fuel cell system operates immediately after startup in freezing conditions, then productivity is maintained, but the coolant may be frozen causing blockages and insufficient hydration and cooling
Solution Approach 1:
The system implements a two-phase startup sequence where the first phase is dedicated to heating the coolant storage tank to thaw frozen coolant before normal operation begins. This preliminary action ensures coolant flow reliability is established before the fuel cell assembly transitions to full productivity mode in the second phase.
Solution Approach 2:
The system dynamically transitions between two operational phases: Phase 1 focuses on heating and thawing coolant with reduced power generation, while Phase 2 transitions to full power generation with coolant flow restored. This dynamic adaptation allows the system to balance productivity requirements with coolant flow reliability based on real-time conditions.
3Power
If the stoichiometric ratio of oxidant flow to fuel flow is increased to generate more power for heating, then the power output for heater operation is improved, but the system efficiency decreases
Solution Approach 1:
During Phase 1, the system operates with an elevated stoichiometric ratio that exceeds normal operational requirements, generating excess power specifically dedicated to heating the coolant. This partial excessive action is temporary and confined to the thawing phase, after which the system transitions to efficient normal operation in Phase 2 with optimized stoichiometric ratios.
Solution Approach 2:
The system employs periodic operation with distinct phases: Phase 1 uses high stoichiometric ratios for a limited duration to generate heating power, then transitions to Phase 2 with optimized ratios for efficient power generation. This periodic switching allows the system to achieve both heating requirements and overall energy efficiency through time-based separation of functions.
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
Enables reliable startup and operation of the fuel cell system in freezing conditions without relying on external power, ensuring a consistent supply of liquid coolant for hydration and cooling, thereby preventing system shutdown and maintaining efficient power generation.
Implementation Method 1
providing the generated electrical power to a heater element (12) to heat the coolant in the coolant storage module (3)
Implementation Method 2
a fuel cell assembly (2) configured to generate electrical power from a fuel flow and an oxidant flow
Implementation Method 3
a coolant injection controller (10) configured to actively control the flow of a coolant to a fuel cell assembly (2) for cooling and/or hydrating the fuel cell assembly (2)
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A coolant injection controller for a fuel cell system, the coolant injection controller configured to actively control the flow of a coolant to a fuel cell assembly for cooling and/or hydrating the fuel cell assembly in response to a measure of fuel cell assembly performance, wherein the coolant injection controller is configured to provide for a first mode of operation if the measure of fuel cell assembly performance is below a predetermined threshold and a second mode of operation if the measure of fuel cell assembly performance is above the predetermined threshold, the first and second modes having different coolant injection profiles and wherein, in the first mode of operation, the coolant injection profile provides for control of the flow of coolant by alternating between at least two different injection flow rates.