Cathode Feedline Heat Exchanger Control for Fuel Cell Air Temperature
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Solution Overview
Problem
Existing solutions for regulating the intake air temperature in fuel cell systems are inefficient and not suitable for decoupled vehicle operations, particularly in vehicles with range extenders, where the fuel cell serves as an additional energy source, as they incur high energy costs and are not effective across varying external temperatures.
Innovation Solution
A temperature regulation system for the cathodic inlet line of a fuel cell using a combination of a cold heat exchanger and a hot heat exchanger associated with the stack cooling loop, with control logic to manage the flow rates of the cooling fluid, allowing for precise temperature adjustment between 60°C-90°C, and optionally using parallel branches with controlled oxygen flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the air compressor increases the pressure to supply air to the fuel cell, then the air supply pressure is improved, but the air temperature rises excessively (e.g., 70°C rise at 30 g/s), which is incompatible with operating temperatures of the battery and humidifier
Solution Approach 1:
The patent introduces a cooling circuit as an intermediary system between the air compressor and the fuel cell components. This cooling circuit uses a coolant circulating through channels to absorb excess heat from the compressed air, thereby mediating the temperature rise caused by compression while maintaining the required pressure supply.
Solution Approach 2:
The cooling circuit is integrated into the existing fuel cell system architecture, using the same coolant that circulates through the fuel cell stack for its own thermal management. This allows the system to self-regulate the air temperature using resources already available in the system, without requiring separate cooling infrastructure.
2Temperature
If the ambient temperature is very low (e.g., -20°C), then the operating conditions are challenging, but the temperature increase at idle is not sufficient to get out of freezing conditions
Solution Approach 1:
The cooling circuit is designed to function bidirectionally for thermal management. In cold conditions, the system can operate in reverse mode where the coolant absorbs heat from the fuel cell stack (which generates heat during operation) and transfers it to the incoming air, thereby warming the air without requiring additional energy input for heating.
Solution Approach 2:
The patent converts the excess heat generated by the fuel cell stack during normal operation into a beneficial resource for warming the incoming air in cold conditions. By reversing the thermal gradient in the cooling circuit, the system transforms waste heat that would otherwise be dissipated into a useful heating source, eliminating the need for separate heating energy consumption.
3Temperature
If existing solutions use outside air via an air/air exchanger or air/water exchanger for cooling, then the intake air temperature can be reduced, but the energy cost is high and the solutions are not suitable for decoupled operation in vehicles with range extenders
Solution Approach 1:
The cooling circuit is designed to serve multiple functions within a single system architecture. It simultaneously cools the compressed air, manages the thermal conditions of the fuel cell stack, and can provide heating in cold conditions by reversing the thermal gradient. This multi-functionality eliminates the need for separate cooling and heating systems, reducing overall energy consumption and system complexity.
Solution Approach 2:
The patent merges the air cooling function with the fuel cell stack thermal management system into a single integrated cooling circuit. By combining these functions, the system eliminates the need for separate air/air exchangers or air/water exchangers, thereby reducing energy costs and enabling decoupled operation in vehicles with range extenders where the fuel cell operates independently of vehicle speed.
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 solution enables optimal operation of the fuel cell across all external temperatures and system conditions by efficiently regulating the intake air temperature, reducing energy costs and avoiding the limitations of existing solutions, particularly in vehicles with range extenders.
Implementation Method 1
a cooling loop passing through an internal compartment of the stack
Implementation Method 2
the said inlet line being associated with thermal regulation means
Implementation Method 3
the said thermal regulation means comprise a first so-called cold heat exchanger and a second so-called hot exchanger
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The invention relates to a method and device for controlling the temperature of a cathode feed line (Ha) of a fuel cell, the cell being cooled by means of a cooling loop that passes through an internal compartment of the cell, the feed line furthermore being cooled, equipped with an internal compartment cooled by means of a cooling loop, said feed line being associated with temperature control means, characterized in that said temperature control means comprise a first cold heat exchanger and a second hot exchanger, associated with the cooling loop of the cell.