Traction Battery Thermal Compound Gap Measurement

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Solution Overview

Problem

The existing methods for producing traction batteries face challenges in minimizing assembly force and mechanical stress on battery modules and housing due to the low viscosity of thermal compounds, which can lead to deformation and damage during the insertion process.

Innovation Solution

A method that involves measuring the actual gap between battery modules and the cooled housing wall, determining the precise amount of thermal compound needed, and applying it to ensure a defined insertion force, monitored and adjusted to prevent excessive stress, using a combination of measurement and light detection for optimal distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a low viscosity thermal compound is used to enable effective heat transfer, then thermal coupling efficiency is improved, but assembly force and mechanical stress increase causing deformation and damage

Engineering Contradiction:
Improvethermal coupling efficiencyVSAvoidassembly force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent applies a high viscosity thermal compound instead of conventional low viscosity compounds. This parameter change in viscosity allows the compound to remain in place during assembly without requiring excessive insertion force, thereby reducing mechanical stress on battery modules and housing while maintaining effective thermal coupling between the cooled housing wall and battery modules

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The thermal compound is applied to the housing wall or battery module before insertion occurs. This preliminary application ensures the compound is already positioned to fill the gap, allowing for controlled distribution during insertion without requiring excessive force that would cause deformation or damage

Inventive Principle:
Principle #10Preliminary action

2Reliability

If high assembly forces are used to ensure proper contact, then thermal coupling is improved, but mechanical stress and deformation of battery modules and housing increase

Engineering Contradiction:
Improvethermal couplingVSAvoidmechanical stress
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

By changing the viscosity parameter of the thermal compound to high viscosity, the compound provides sufficient structural support during assembly. This eliminates the need for high insertion forces to ensure proper contact, as the high viscosity compound maintains its position and ensures continuous thermal contact without requiring excessive mechanical stress

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The high viscosity thermal compound acts as a cushioning material applied beforehand. It compensates for gaps and irregularities between the housing wall and battery modules, distributing mechanical stresses evenly during assembly and preventing localized deformation or damage to the battery modules and housing structure

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 approach reduces the insertion force and assembly force required, minimizing the risk of damage to battery modules and housing while ensuring effective thermal coupling for cooling.

Implementation Method 1

a thermally conductive paste is applied to the battery cells, via which the battery cells are at least thermally coupled to a cooler for cooling the battery cells

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the reaching of the insertion position is monitored with a light measuring device

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentEP3925019B1Method for producing a traction battery of a motor vehicle
Publication Date: 2023.06.28 LISA DRAXLMAIER GMBH
  • EP3925019B1 patent drawingFigure 1~3

AI summary

Method for producing a traction battery of a motor vehicle, wherein the traction battery (10) comprises a housing (11) and a plurality of battery modules (14) accommodated in the housing (11), and wherein a pasty heat-conducting compound (16) for thermally coupling the battery modules (14) with a cooled housing wall (13) of the housing (11) is arranged between the battery modules (14) and the cooled housing wall (13), having the following steps of: providing the housing (11) and the battery modules (14), measuring at least one portion of the particular battery module (14) and/or at least one portion of the housing (11), determining an actual gap between the battery module (14) and the cooled housing wall (13) depending on the measurement, determining an amount of heat-conducting compound (16) depending on the determined actual gap, applying the determined amount of heat-conducting compound (16) to the cooled housing wall (13) and/or the particular battery module (14), inserting the particular battery module (14) into the housing (11) with a defined insertion force, with heat-conducting compound (16) being distributed between the particular battery module (14) and the cooled housing wall (13) of the housing (11).