Fuel Cell Unit Boost Converter Heat Management

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Solution Overview

Problem

Fuel cell units in electric vehicles face spatial restrictions, and as they shrink, the boost converter is subjected to excessive heat from the fuel cell stack, particularly affecting components like current sensors and capacitors with low temperature limits, for which cooling is difficult.

Innovation Solution

The fuel cell unit design accommodates the fuel cell stack and boost converter in the same case without a heat shielding member, with the current sensor and capacitor positioned on the upstream side of the coolant channel, where the temperature is relatively low, allowing for reduced size while protecting these components from heat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the fuel cell stack and boost converter are accommodated in the same case without a heat shielding member, then the size of the fuel cell unit is reduced, but the boost converter components (current sensor and capacitor) are subjected to excessive heat from the fuel cell stack

Engineering Contradiction:
Improvesize of fuel cell unitVSAvoidtemperature of boost converter components
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The patent applies local quality by positioning the current sensor and capacitor at specific locations within the boost converter - on the upstream side from the middle of the coolant channel. This creates a localized cool region where heat-sensitive components are placed, while other parts of the boost converter can be positioned in warmer regions. The solution does not uniformly cool the entire boost converter but rather creates a favorable thermal micro-environment for specific sensitive components.

Inventive Principle:
Principle #3Local quality

2Volume of moving object

If the size of the fuel cell unit is reduced, then spatial restrictions in vehicles are addressed, but cooling of heat-sensitive components becomes more difficult

Engineering Contradiction:
Improvesize of fuel cell unitVSAvoidcooling difficulty of components
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The patent implements preliminary action by pre-positioning the current sensor and capacitor on the upstream side of the coolant channel before the components would be subjected to excessive heat. The coolant flow pattern is designed in advance to create a favorable thermal environment for these components. By anticipating the thermal challenges and designing the component layout and coolant flow path together, the system achieves effective cooling without requiring additional cooling mechanisms or increasing overall unit size.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If heat shielding members are used to protect current sensor and capacitor, then components are protected from heat, but the size of the fuel cell unit increases

Engineering Contradiction:
Improveprotection of current sensor and capacitorVSAvoidsize of fuel cell unit
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent extracts the heat shielding function from a separate physical barrier (heat shielding member) and integrates it into the thermal management system design. Instead of adding a dedicated shielding component between the fuel cell stack and boost converter, the solution extracts the protective function by strategically positioning components within the existing coolant flow field. The coolant flow itself serves as the thermal barrier, eliminating the need for additional heat shielding structures.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies universality by making the coolant channel serve multiple functions: it cools the fuel cell stack and simultaneously creates a protective thermal environment for the boost converter components. The coolant flow path is designed to fulfill both the primary cooling function and the secondary heat protection function, eliminating the need for separate heat shielding components and reducing overall system complexity and size.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 reduces the size of the fuel cell unit while safeguarding critical components from heat damage, maintaining a tolerable temperature range and ensuring efficient cooling.

Implementation Method 1

a coolant channel inside which coolant flows in one direction

Methodology Applied
Scientific EffectHeat transfer: Convection

Data Source

PatentEP3866240B1Fuel cell unit
Publication Date: 2022.08.24 TOYOTA JIDOSHA KK
  • EP3866240B1 patent drawingFigure 1~2
  • EP3866240B1 patent drawingFigure 3~4
  • EP3866240B1 patent drawingFigure 5A~5B

AI summary

A fuel cell unit (10) includes a fuel cell stack (20) having a coolant channel (23) inside where coolant flows in one direction, and having a first surface (27) parallel to a direction in which the coolant channel extends; a boost converter (40) disposed across a gap from the first surface (27) without being partitioned by a heat shielding member, the boost converter (40) including a current sensor (43) and a capacitor (45) disposed following the first surface; and a case (30) that accommodates the fuel cell stack (20) and the boost converter (40) in a same space, wherein at least one of the current sensor (43) and the capacitor (45) is disposed on an upstream side from a middle of the coolant channel, in the direction in which the coolant channel extends.