Cell Housing Insulation via Composite Foil Folding

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Solution Overview

Problem

In high-voltage batteries for hybrid and electric vehicles, voltage flashovers can occur due to insufficient insulation between the cell housing and the battery case, particularly at the cut edges of aluminum composite foils, which are prone to contact and compromise electrical insulation.

Innovation Solution

The cut edge of a cell housing made of composite foil is insulated by folding the foil at the cut edge and bending the insulating layer to create a secure barrier between the electrically conductive layer and the outside environment, ensuring that the electrically conductive layer is shielded from potential flashovers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the cell housing uses aluminum composite foil with cut edges, then the electrical conductivity and heat dissipation are improved, but the insulation reliability deteriorates due to exposed conductive edges prone to voltage flashovers

Engineering Contradiction:
Improveelectrical conductivityVSAvoidinsulation reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The composite foil is segmented into distinct functional layers (insulating layer and conductive layer) that are folded to create separate insulated and conductive zones, preventing direct contact between conductive edges and the battery case while maintaining electrical conductivity where needed

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conductive layer is nested within the insulating layer through folding, creating a protective structure where the insulating layer surrounds and protects the exposed conductive edges, eliminating voltage flashover risks while preserving electrical functionality

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If additional insulation components and assembly steps are added to prevent voltage flashovers, then the insulation reliability is improved, but the device complexity and assembly work increase

Engineering Contradiction:
Improveinsulation reliabilityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The insulation function is merged with the cell housing structure itself by folding the composite foil, eliminating the need for separate insulation components such as Kapton tapes and reducing assembly complexity while maintaining insulation reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The composite foil structure performs its own insulation function through folding, where the housing material itself creates the insulation barrier, eliminating dependency on additional insulating components and simplifying the overall assembly process

Inventive Principle:
Principle #25Self-service

3Reliability

If larger distances are maintained for insulation, then the insulation reliability is improved, but the installation space increases making vehicle integration more difficult

Engineering Contradiction:
Improveinsulation reliabilityVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The insulation solution transitions from a spatial distance approach to a dimensional folding approach, where the composite foil is folded to create insulation in a different spatial configuration, maintaining compact vehicle integration while ensuring insulation reliability through structural design rather than increased spacing

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

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 method effectively prevents voltage flashovers between the arrester and the cell housing, reducing assembly complexity and ensuring reliable insulation during production, while allowing for integration into vehicle packages without increasing installation space.

Implementation Method 1

the insulating layer (102) with its inside (102b) bordering on an outside (102a) of the cell housing (110) is folded over and the inside (102b) is glued to the outside (102a) of the cell housing (110)

Methodology Applied
Scientific EffectPhysical barrier insulation:

Data Source

PatentEP2327117B1Cell housing for a galvanic element
Publication Date: 2019.02.27 MAHLE BEHR GMBH & CO
  • EP2327117B1 patent drawingFigure 1~2
  • EP2327117B1 patent drawingFigure 3~4
  • EP2327117B1 patent drawingFigure 5~6

AI summary

The present invention relates to a cell housing for a galvanic element, wherein the cell housing comprises a composite film with an insulating layer (102) and an electrically conducting layer (103), characterized in that an end section of the composite film has a bend (110) suitable for forming an insulation for the electrically conducting layer (103).