Fuel Cell Water Draining via Bypass Suction to Prevent Freezing

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Solution Overview

Problem

Conventional methods for draining water from fuel cell systems to prevent freezing, such as using an air compressor, consume excessive power, cause unnecessary oxygen flow that oxidizes the electrolyte, and may leave residual water, leading to ineffective prevention of freezing issues.

Innovation Solution

A fuel cell system with a fuel-gas flow path, oxygen-containing-gas flow path, and cooling-water flow path, utilizing bypass pipes and a suction pump to drain water by pressurizing and then suctioning water from these paths, reducing power consumption and minimizing electrolyte oxidation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an air compressor is used to eject oxygen-containing gas to blow out water from the fuel cell stack and discharge system piping, then water can be discharged to outside, but power consumption increases excessively and the electrolyte layer is oxidized causing deterioration

Engineering Contradiction:
Improveprevention of freezingVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the water discharge function from the oxygen-containing gas flow path and creates a separate cooling water flow path with bypass pipes. This separates the harmful oxygen exposure from the necessary water removal operation, allowing water to be discharged without requiring oxygen-containing gas flow through the fuel cell stack.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces cooling water as an intermediary substance to carry out water discharge. Instead of using oxygen-containing gas directly, cooling water flows through the bypass pipes to transport water from the fuel cell stack and discharge system piping to the outside, acting as a mediator that performs the discharge function without causing oxidation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If an air compressor is used to eject oxygen-containing gas to blow out water from the fuel cell stack and discharge system piping, then water can be discharged to outside, but a large amount of oxygen-containing gas flows into the fuel cell stack causing electrolyte layer oxidation and deterioration

Engineering Contradiction:
Improveprevention of freezingVSAvoidelectrolyte layer
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent extracts the water discharge function from the oxygen-containing gas flow path and creates a separate cooling water flow path with bypass pipes. This separates the harmful oxygen exposure from the necessary water removal operation, allowing water to be discharged without requiring oxygen-containing gas flow through the fuel cell stack.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates an inert environment for water discharge by using cooling water instead of oxygen-containing gas. The cooling water flow path provides a non-oxidizing medium that transports water out of the system without exposing the electrolyte layer to oxygen, effectively creating a protective atmosphere during the discharge operation.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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

Effectively drains water from the fuel cell system to prevent freezing, reducing power consumption and minimizing electrolyte oxidation, thereby ensuring the system operates efficiently and safely.

Implementation Method 1

a suction pump provided in the cooling-water flow path on a downstream side of a connecting portion between the cooling-water flow path and the first bypass pipe and a connecting portion between the cooling-water flow path and the second bypass pipe

Methodology Applied
Scientific EffectSuction: Suction

Data Source

PatentEP4528861A1Fuel cell system and water draining method of fuel cell system
Publication Date: 2025.03.26 KK TOSHIBA
  • EP4528861A1 patent drawingFigure 1
  • EP4528861A1 patent drawingFigure 2
  • EP4528861A1 patent drawingFigure 3

AI summary

A fuel cell system of an embodiment includes a fuel cell stack including a fuel electrode layer, an oxidizer electrode layer, and a cooling layer, a fuel-gas flow path configured to allow the fuel gas from the fuel electrode layer to pass therethrough, an oxygen-containing-gas flow path configured to allow the oxygen-containing gas from the oxidizer electrode layer to pass therethrough, a cooling-water flow path, a first bypass pipe configured to guide water in the fuel-gas flow path to the cooling-water flow path, a second bypass pipe configured to guide water in the oxygen-containing-gas flow path to the cooling-water flow path, and a suction pump provided in the cooling-water flow path on the downstream side of a connecting portion between the cooling-water flow path and the first bypass pipe and a connecting portion between the cooling-water flow path and the second bypass pipe.