Liquid Hydrogen Tank Venting With Water-Forming Pressure Relief

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Solution Overview

Problem

Existing liquid hydrogen storage systems for vehicles face challenges in safely managing internal tank pressure, leading to potential excessive pressure increases and safety concerns.

Innovation Solution

A liquid hydrogen storage system with multiple safety valves and channels configured to discharge hydrogen gas safely outside the vehicle, while avoiding high-temperature areas, and incorporating a closure member that destroys at high pressure to ensure safe discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If liquid hydrogen is stored in a vehicle, then hydrogen can be used as an energy source, but excessive internal tank pressure increases safety risks

Engineering Contradiction:
ImprovesafetyVSAvoidinternal tank pressure
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The patent divides the pressure relief function into multiple independent channels: a first channel with a first safety valve for controlled discharge, and a second channel with a second safety valve as backup. This segmentation ensures that if one channel fails, the other can still prevent excessive pressure buildup, thereby maintaining safety while managing internal tank pressure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preemptive safety measures by providing multiple safety valves and discharge channels before pressure becomes dangerous. The first safety valve opens at a lower pressure threshold to prevent excessive pressure buildup, while the second safety valve provides additional protection. This prior cushioning approach prevents the harmful effect of excessive pressure rather than responding to it after occurrence.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Stress or pressure

If hydrogen gas is discharged to the outside, then internal tank pressure is suppressed, but unprocessed hydrogen gas creates safety hazards

Engineering Contradiction:
Improveinternal tank pressureVSAvoidsafety hazard from discharged hydrogen gas
Core Design Contradiction:
Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a reaction section as an intermediary between the hydrogen gas discharge and the external environment. This reaction section processes the hydrogen gas through chemical reaction with oxygen to produce water, thereby eliminating the safety hazards of unprocessed hydrogen gas while still achieving pressure relief. The intermediary transforms the harmful substance into a harmless product.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful hydrogen gas that needs to be discharged into a beneficial process by facilitating its reaction with oxygen to produce water. Instead of simply venting potentially explosive hydrogen gas to the environment, the system uses the discharged gas in a controlled chemical reaction that eliminates safety hazards and produces a harmless byproduct, thereby turning a harmful discharge into a beneficial safety mechanism.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If multiple safety valves are added, then pressure control improves, but system complexity increases

Engineering Contradiction:
Improvepressure controlVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the pressure control function into two independent safety valve systems operating in parallel with different activation thresholds. This segmentation allows each valve to be simpler in design while collectively providing robust pressure control. The first safety valve handles normal pressure relief, while the second provides backup protection, dividing the complex safety function into manageable independent units.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different characteristics to different parts of the pressure control system: the first safety valve operates at a lower pressure threshold for routine pressure management, while the second safety valve operates at a higher threshold for emergency protection. This local differentiation of valve characteristics optimizes overall system performance without requiring all components to be equally complex.

Inventive Principle:
Principle #3Local quality

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 system effectively suppresses excessive internal tank pressure, ensures safe discharge of hydrogen gas, and enhances occupant safety by providing a warning mechanism and avoiding high-temperature areas for gas discharge.

Implementation Method 1

a reaction section that causes hydrogen gas flowing through the first channel to react with oxygen for conversion into water

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

when liquid hydrogen is vaporized to produce a large amount of hydrogen gas in the liquid hydrogen storage tank

Methodology Applied
Scientific EffectVaporization: Evaporation

Data Source

PatentEP4303428B1Hydrogen engine vehicle with liquid hydrogen storage system
Publication Date: 2025.06.04 TOYOTA JIDOSHA KK
  • EP4303428B1 patent drawingFigure 1
  • EP4303428B1 patent drawingFigure 2
  • EP4303428B1 patent drawingFigure 3

AI summary

A liquid hydrogen storage system (10) includes: a hydrogen tank (12) that stores liquid hydrogen; a first channel (24) that communicates between the hydrogen tank (12) and outside of a vehicle; a reaction section (25) that causes hydrogen gas flowing through the first channel (24) to react with oxygen for conversion into water and discharges water to the outside of the vehicle through the first channel (24); and a first safety valve (20) that is provided between the hydrogen tank (12) and the reaction section (25), and is opened at the time when an internal tank pressure (Pt) as an internal pressure of the hydrogen tank (12) exceeds a first open reference value (Po1), so as to discharge the hydrogen gas in the hydrogen tank (12) to the reaction section (25).