Fuel Cell Stack Clamping Device With Molded Insulation

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Solution Overview

Problem

Existing fuel cell stack designs face challenges in achieving effective sealing and electrical insulation, leading to moisture penetration and increased production complexity and costs.

Innovation Solution

A fuel cell stack design featuring a clamping device with molded-on insulation and a circumferential lip seal, utilizing materials like rubber, polyvinyl chloride, and thermoplastic polyurethane, which are electrically insulating and chemically resistant, to prevent moisture ingress and simplify the sealing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a clamping device is used to clamp the fuel cell units and stack closure element, then the sealing and electrical insulation are improved, but the device complexity increases due to the need for molded-on insulation and integration with the seal

Engineering Contradiction:
Improvesealing and electrical insulationVSAvoidclamping device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The clamping device integrates multiple functions into a single component: the clamping function (mechanical fastening), the sealing function (circumferential seal), and the electrical insulation function (molded-on insulation). This merging of functions resolves the contradiction by achieving reliable sealing and insulation without requiring separate components for each function, thus not increasing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The clamping device utilizes composite material structures, specifically the combination of the clamping device base material with molded-on insulation material. This composite approach provides both mechanical clamping strength and electrical insulation properties in a single integrated component, resolving the contradiction between reliability (sealing and insulation) and device complexity.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If a circumferential seal with recesses for the clamping device is used, then moisture penetration is prevented, but the manufacturing precision requirements increase due to the need for precise recess positioning

Engineering Contradiction:
Improvemoisture penetrationVSAvoidrecess positioning accuracy
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The recesses for the clamping device are pre-formed as integral features of the stack closure element during its manufacturing process. This preliminary action ensures precise positioning of the recesses relative to the sealing surface, eliminating the need for post-assembly adjustments and ensuring proper alignment for effective moisture prevention without requiring excessive manufacturing precision in subsequent assembly steps.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If insulation is molded onto the clamping device in the area of the housing, then electrical insulation of adjacent fuel cell units is improved, but the production costs increase due to the additional molding process

Engineering Contradiction:
Improveelectrical insulationVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The insulation is molded onto the clamping device as an integrated feature during the clamping device manufacturing process itself, rather than as a separate post-processing step. This merging of the insulation application with the base component manufacturing utilizes existing molding capabilities, avoiding additional production steps and costs while still achieving improved electrical insulation of adjacent fuel cell units.

Inventive Principle:
Principle #5Merging (Combining)

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 provides a reliable sealing system that prevents moisture penetration, reduces production costs, and optimizes installation space, while ensuring electrical insulation and efficient assembly of the fuel cell stack.

Implementation Method 1

a circumferential seal, in particular a lip seal, is arranged between the housing and the at least one stack closure element

Methodology Applied
Scientific EffectSealing:

Implementation Method 2

the clamping device being electrically insulated at least in the region of the recesses

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP2803106B1Fuel cell stack
Publication Date: 2016.09.28 MERCEDES BENZ GROUP AG
  • EP2803106B1 patent drawingFigure 1~2
  • EP2803106B1 patent drawingFigure 3~4
  • EP2803106B1 patent drawingFigure 5

AI summary

The invention relates to a fuel cell stack (1) which is made of a plurality of stacked fuel cell units (2) and at least one stack terminating element (3). The stacked fuel cell units (2) and the stack terminating element (3) can be clamped by means of a clamping device (4), and at least the clamped fuel cell units (2) are surrounded by a housing (7). A peripheral seal (6), in particular a lip seal (6.1), which has recesses (6.2) for receiving the clamping device (4), is arranged between the housing (7) and the at least one stack terminating element (3), said clamping device (4) being electrically insulated at least in the region of the recesses (6.2).