Liquid Hydrogen Tank Insulation Structure for Impact Protection

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Solution Overview

Problem

Conventional in-vehicle liquid hydrogen tanks face issues with damage and hydrogen leakage due to strong impacts, as the shock-absorbing material can be damaged, causing the inner tank to collide with the outer tank, which compromises the heat-insulation and structural integrity.

Innovation Solution

The design incorporates a heat-insulation clearance with a vacuum area and a filled area using superinsulation material, which surface-supports the inner tank, preventing collisions and maintaining high heat-insulation properties, while also including a rupture disc for pressure management and a booster pump for pressure control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If shock-absorbing material is used to hold the inner tank, then the inner tank can be protected during normal operation, but the shock-absorbing material may be damaged or deformed during strong impact, causing the inner tank to collide with the outer tank

Engineering Contradiction:
Improveprotection of inner tankVSAvoidresistance to strong impact
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The heat-insulation clearance is divided into multiple regions: a first region filled with heat-insulation material for surface support, and a second region as vacuum area for enhanced heat insulation. This segmentation allows different functional zones to work together, providing both mechanical support and impact protection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heat-insulation material acts as an intermediary between the inner tank and the outer tank, providing surface support to the inner tank while the vacuum area provides additional protection. This intermediary structure prevents direct contact between the tanks during impact.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If vacuum heat-insulation layer is used between outer tank and inner tank, then heat transfer to inner tank is inhibited and vaporization of liquid hydrogen is suppressed, but the inner tank may collide with outer tank during vehicle collision due to lack of mechanical support

Engineering Contradiction:
Improveheat insulation propertyVSAvoidprotection during collision
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The heat-insulation clearance is segmented into a first region filled with heat-insulation material and a second region as vacuum area. This segmentation combines the mechanical support function of the heat-insulation material with the superior heat insulation function of the vacuum area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses a composite structure combining heat-insulation material and vacuum space to achieve both mechanical support and thermal insulation functions simultaneously, rather than relying on a single material or method.

Inventive Principle:
Principle #40Composite materials

3Reliability

If the heat-insulation clearance is completely filled with heat-insulation material, then the inner tank is well-supported and protected during collision, but the heat-insulation property decreases due to increased heat transfer through the material

Engineering Contradiction:
Improveprotection during collisionVSAvoidheat insulation property
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The heat-insulation clearance is divided into regions with different filling ratios. The first region has a higher filling ratio for support, while the second region has a lower or zero filling ratio for enhanced heat insulation, optimizing both functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the heat-insulation clearance have different qualities: the first region near the inner tank has heat-insulation material for surface support, while the second region has vacuum for superior heat insulation. Each region is optimized for its specific function.

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

This configuration effectively prevents damage to the inner tank during collisions, maintains high heat-insulation properties, and ensures stable storage of liquid hydrogen by preventing direct contact between the inner and outer tanks, thus enhancing safety and reducing costs and weight.

Implementation Method 1

a vacuum area that is not filled with the heat-insulation material

Methodology Applied
Scientific EffectVacuum insulation: Vacuum

Implementation Method 2

In the vacuum area, heat is not transferred except by radiation

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 3

an area that is filled with the heat-insulation material and thus allows the inner tank to be surface-supported by the heat-insulation material

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4303054A1In-vehicle liquid hydrogen tank and a method for manufacturing the same
Publication Date: 2024.01.10 TOYOTA JIDOSHA KK
  • EP4303054A1 patent drawingFigure 1
  • EP4303054A1 patent drawingFigure 2
  • EP4303054A1 patent drawingFigure 3

AI summary

An in-vehicle liquid hydrogen tank (10) includes: an inner tank (12) that stores liquid hydrogen; an outer tank (14) that accommodates the inner tank (12); and a heat-insulation material (16) that is arranged in a heat-insulation clearance (18) as a clearance between the inner tank (12) and the outer tank (14) and holds the inner tank (12) to be separated from an inner surface of the outer tank (14). The heat-insulation clearance (18) has: a vacuum area (17) that is not filled with the heat-insulation material (16); and an area that is filled with the heat-insulation material (16) and thus allows the inner tank (12) to be surface-supported by the heat-insulation material (16).