Stacked Element Laser Soldering via Thermal Model

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing methods for soldering multiple stacked electronic elements are inefficient due to the empirical adjustment of laser parameters, which can lead to poor quality soldering or damage to elements, especially when dealing with three or more elements, as they fail to accurately account for the increasing number of thermal characteristics.

Innovation Solution

A mathematical model is developed to precisely determine laser parameters, using a computer program that incorporates thermal characteristics like critical damage temperatures and melting temperatures, and is implemented through experimental designs such as Box Behnken or D-optimal designs to ensure accurate and rapid adjustment of irradiation duration, surface, and power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If empirical adjustment of laser parameters is used, then the process is simple to operate, but the soldering quality deteriorates when dealing with three or more elements due to inability to account for all thermal characteristics

Engineering Contradiction:
Improveease of parameter adjustmentVSAvoidsoldering quality
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent transforms the laser parameters (power, duration, surface) from empirically adjusted values into mathematically determined values based on thermal characteristics of each element. The mathematical model calculates optimal parameter combinations by considering melting temperatures and critical damage temperatures of all elements, thereby improving soldering quality while maintaining operational simplicity through automated calculation.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If empirical adjustment method is used, then the adjustment process is rapid, but the precision of parameter determination deteriorates due to randomness and inability to consider all thermal characteristics

Engineering Contradiction:
Improvespeed of parameter adjustmentVSAvoidparameter determination accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary calculation of optimal laser parameters using a mathematical model that considers all thermal characteristics of the elements before the actual soldering process. By pre-determining the parameter values through mathematical optimization rather than empirical trial-and-error, the system achieves both rapid adjustment and high precision in parameter determination.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If laser parameters are adjusted to ensure solder melting, then the soldering quality improves, but the risk of damaging elements increases due to exceeding critical temperatures

Engineering Contradiction:
Improvesoldering qualityVSAvoidelement damage risk
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The mathematical model determines laser parameters by considering both the melting temperature of the solder and the critical damage temperature of each element. The model calculates parameter combinations that achieve solder melting while maintaining temperatures below the critical damage thresholds, thereby improving soldering quality without increasing element damage risk.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent incorporates thermal characteristics (melting temperatures and critical damage temperatures) as feedback parameters in the mathematical model. This feedback mechanism allows the system to automatically adjust laser parameters to achieve the desired soldering effect while preventing element damage, creating a self-regulating process that balances soldering quality and element protection.

Inventive Principle:
Principle #23Feedback

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 allows for quick and precise adjustment of laser parameters, ensuring high-quality soldering without damaging the elements by accurately accounting for thermal characteristics, regardless of the number of elements in the stack, resulting in improved solder quality and reliability.

Implementation Method 1

a laser is directed onto an end face of the stack so that the laser heats the battery

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

the maximum temperature reached of the cell is higher than the melting temperature of the mass forming solder

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP1993771B1Method of welding together at least two stacked members
Publication Date: 2014.04.30 VALEO EQUIP ELECTRIC MOTEUR
  • EP1993771B1 patent drawingFigure 1~2
  • EP1993771B1 patent drawingFigure 3~4

AI summary

In accordance with this welding method, a laser (24) is directed onto an end face (F) of the stack (18) in such a way that the laser (24) heats the stack (18). At least one parameter of the laser (24) is adjusted to a value which is the image through a mathematical model of at least one thermal characteristic of the stack (18). The parameter of the laser (24) is a parameter chosen from a duration of irradiation, an area of irradiation of the end face of the stack by the laser and an irradiation power of the laser (24).