Fuel Cell Stack End-Terminal Layout for Compact Power Density

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Solution Overview

Problem

Compact fuel cell stack designs for transportation applications face challenges in achieving high power density and economical manufacturing due to larger dimensions caused by electrical connectors and complex wiring, which hinder modular packaging in restricted spaces.

Innovation Solution

A fuel cell stack assembly with optimized end-portions featuring an output terminal, electrically conductive bus plate, insulating isolator plate, load distribution plate, and o-ring seals, allowing for reduced dimensions, simplified connections, and cost-effective assembly using similar parts and processes, enabling higher volumetric power density and modular arrangement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If electrical connectors and wiring are arranged on the outside of the fuel cell stack, then electrical connections can be established, but the overall dimensions of the fuel cell stack increase

Engineering Contradiction:
Improvevolumetric power densityVSAvoidoverall dimensions
Core Design Contradiction:
Volume of moving objectVSLength of stationary object

Solution Approach 1:

The output terminal is nested within the planar dimensions of the load distribution plate, with the terminal penetrating through openings in both the isolator plate and load distribution plate. This nesting arrangement integrates the electrical connector within the existing stack structure rather than adding external protrusions, thereby reducing overall dimensions while maintaining electrical connection functionality

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The output terminal is arranged to reach through the stacking direction (vertical dimension) rather than extending horizontally from the stack exterior. By transitioning the connector orientation from horizontal external arrangement to vertical internal penetration, the design reduces the horizontal footprint and overall external dimensions of the fuel cell stack

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If complex wiring arrangements are used for electrical connectors, then electrical power can be supplied, but manufacturing and assembly costs increase

Engineering Contradiction:
Improvemanufacturing and assembly costsVSAvoidwiring complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The output terminal combines multiple functions into a single integrated component: it serves as the electrical connector for power output, penetrates through both the isolator plate and load distribution plate, and provides structural support. This merging of functions reduces the number of separate wiring components and simplifies both manufacturing and assembly processes

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The load distribution plate serves multiple purposes: it distributes mechanical load across the stack, provides electrical insulation through the isolator plate, and accommodates the output terminal penetration. This multi-functionality reduces the need for separate dedicated components for each function, thereby simplifying the overall design and reducing manufacturing complexity

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

The solution achieves industry-leading volumetric power densities and cost reduction while enabling a spatially-dense modular arrangement and quick 'plug-and-play' connections, enhancing operational safety and assembly efficiency.

Implementation Method 1

an electrically conductive bus plate for collecting a current flowing through the cells of the fuel cell stack, arranged in electrical contact between the last individual stacked unit cell and the output terminal

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

an electrically insulating isolator plate for electrical disconnection, arranged between the bus plate and the load distribution plate

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 3

A feature of this invention is a unique usage of o-ring seals to provide an electrical creepage barrier; such o-rings are placed between the isolator plate and the output terminal cap to extend the creepage path between the output terminal and the load-distribution plate

Methodology Applied
Scientific EffectElectrical creepage barrier: Electrical Resistance

Data Source

PatentEP4325609A1Fuel cell stack assembly and fuel cell device including the same
Publication Date: 2024.02.21 AVL LIST GMBH
  • EP4325609A1 patent drawingFigure 1
  • EP4325609A1 patent drawingFigure 2
  • EP4325609A1 patent drawingFigure 3

AI summary

The present invention relates to a fuel cell stack assembly for the end portions of a fuel cell stack having individual, stacked unit cells. The fuel cell stack assembly comprises an output terminal (20), an electrically conductive bus plate (10), a load distribution plate (60) covering outer side, and an electrically insulating isolator plate (40) arranged between the bus plate (10) and the load distribution plate (60). According to the invention, the output terminal (20) is arranged within planar dimensions of the load distribution plate (60), and reaches to the outside through an opening (40a) in the isolator plate (40) and through an opening (60a) in the load distribution plate (60) in a stacking direction (S) of the fuel cell stack.