Hydrogen Tank Relief Pressure Reduction for Polymer Pipes

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Solution Overview

Problem

Existing high-pressure tanks in hydrogen-powered vehicles use stainless steel pipes for thermal pressure relief, which are heavy and expensive, necessitating a cost-effective and lightweight alternative.

Innovation Solution

Incorporating a pressure reducer, such as a throttle valve or Laval nozzle, within the thermal pressure relief device to reduce pressure effectively, allowing the use of lighter and cheaper polymer materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If stainless steel pipes are used for thermal pressure relief devices, then mechanical strength and pressure resistance are improved, but weight and manufacturing cost increase

Engineering Contradiction:
Improvepressure resistanceVSAvoidpipe weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The pressure relief system is divided into two functional sections: a high-pressure section (outlet to pressure reducer) that requires stainless steel for strength, and a low-pressure section (after pressure reducer) that can use lightweight polymer pipes. This segmentation allows each material to be used only where necessary, reducing overall weight while maintaining pressure resistance where needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pressure reducer changes the pressure parameter from high (several hundred bar) to low (suitable for polymer pipes). This parameter transformation enables the use of polymer materials in the downstream section, as the reduced pressure eliminates the need for high-strength stainless steel, thereby reducing weight and cost.

Inventive Principle:
Principle #35Parameter changes

2Strength

If stainless steel pipes are used for thermal pressure relief devices, then mechanical strength is improved, but manufacturing cost increases

Engineering Contradiction:
Improvemechanical strengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The pipe system is segmented into high-pressure and low-pressure zones separated by the pressure reducer. Only the critical high-pressure section uses expensive stainless steel, while the majority of the pipe system (downstream section) uses inexpensive polymer materials, significantly reducing overall manufacturing cost.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By changing the pressure parameter through the pressure reducer, the system enables the use of cost-effective polymer materials in the low-pressure section. This parameter transformation makes the downstream pipe section much cheaper to manufacture while still fulfilling its function.

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If pressure is reduced in the thermal pressure relief device, then material cost and weight are reduced, but pressure management complexity increases

Engineering Contradiction:
Improvepipe weightVSAvoidpressure management
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The pressure reducer acts as an intermediary device between the high-pressure tank and the low-pressure pipe system. This single intermediate component manages the pressure transition, simplifying the overall pressure management while enabling the use of lightweight polymer pipes downstream.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The pressure reducer replaces the need for a fully robust mechanical pressure-containing system throughout the entire pipe length. By substituting the high-strength mechanical requirement with a pressure-reducing mechanism, the system achieves weight reduction while maintaining functional integrity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution achieves a low pipe pressure during relief, reducing manufacturing costs and weight while maintaining effective fuel flow management.

Implementation Method 1

a pressure reducer (1) is provided in the thermal pressure relief device (20) for reducing the pressure when the high-pressure tank (10) is relieved

Methodology Applied
Scientific EffectPressure reduction: Pressure Drop

Implementation Method 2

the pressure reducer is a throttle valve (7), wherein the throttle valve has a throttle opening (8). Due to the throttle valve, the pressure is effectively reduced downstream, or in the flow direction

Methodology Applied
Scientific EffectThrottling: Pressure Drop

Implementation Method 3

The pressure reducer is a Laval nozzle (5), which has a convergent section (2) and a divergent section (6). The Laval nozzle (5) allows the static pressure to be reduced without lowering the total pressure in the system

Methodology Applied
Scientific EffectLaval nozzle effect: De Laval Nozzle

Data Source

PatentEP4508364B1Pressure reducer for enabling the use of polymer pipes for thermal pressure relief devices of hydrogen-operated vehicles
Publication Date: 2026.03.04 NORMA GERMANY GMBH
  • EP4508364B1 patent drawingFigure 1a~1c

AI summary

The invention relates to a pressure-reducing system for a high-pressure tank (10), in particular for a high-pressure tank (10) of a motor vehicle, in which high-pressure tank (10) a fluid is stored under positive pressure, wherein the high-pressure tank (10) has an outlet (9) for relieving the pressure, wherein the high-pressure tank (10) is fluidically connected via the outlet (9) to a thermal pressure relief device (20) through which the fluid flows in the flow direction (x) when pressure is being relieved. According to the invention, a pressure reducer (1) for reducing the pressure when relieving the high-pressure tank (10) of pressure is provided in the thermal pressure relief device (20).