Busbar Weld Quality Detection Using Contact Temperature Sensors

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Solution Overview

Problem

Defining the quality of busbar weldings is difficult and burdensome, especially with reflective surfaces, as existing methods like thermal cameras can be unreliable, potentially leading to battery failure due to poor weldings causing increased resistance and voltage drop.

Innovation Solution

A method and arrangement using a holder with temperature sensors arranged according to welding spots, applying a contacting force to measure temperature responses, which allows for quick and reliable assessment of welding quality, even on glossy or reflective busbars, by heating the busbar and analyzing temperature changes with a data managing system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If thermal cameras are used to define welding quality, then measurement can be performed remotely, but the measurements are unreliable due to reflective surfaces of busbars

Engineering Contradiction:
Improveremote measurement capabilityVSAvoidmeasurement reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces temperature sensors as intermediary devices that physically contact the busbar at measuring spots to directly measure temperature. This mediator approach bypasses the reflective surface problem of thermal cameras by using contact-based measurement, thereby improving measurement reliability while maintaining operational efficiency

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the optical measurement system (thermal camera) with a thermal conduction-based measurement system (contact temperature sensors). This substitution eliminates the interference caused by reflective surfaces by using direct thermal contact to measure temperature at welding spots

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If traditional welding quality definition methods are used, then measurement can be performed, but the process is difficult and burdensome

Engineering Contradiction:
Improvewelding quality assessment accuracyVSAvoidmeasurement process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the busbar into multiple measuring spots, each with dedicated temperature sensors arranged in a predetermined pattern. This segmentation allows independent measurement at each welding location, simplifying the overall measurement process while maintaining comprehensive coverage and precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the measurement parameter from visual/optical inspection to direct temperature measurement. By measuring temperature response at specific spots during controlled heating, the system transforms a complex quality assessment into a straightforward thermal response evaluation

Inventive Principle:
Principle #35Parameter changes

3Reliability

If contact temperature sensors are used to measure welding quality, then measurement reliability is improved, but the contacting force may cause movement or bending of the busbar

Engineering Contradiction:
Improvetemperature measurement reliabilityVSAvoidbusbar structural stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies a limited contacting force that is sufficient to ensure good thermal contact between sensors and busbar surface, but controlled to be below the threshold that would cause busbar movement or bending. This partial action approach achieves measurement reliability without compromising structural stability

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent implements force limiting devices on temperature sensors before measurement begins. This pre-established force constraint prevents excessive contacting force from causing busbar displacement, ensuring both measurement reliability and structural stability throughout the measurement process

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 provides a quick and reliable method to assess busbar welding quality, reducing measurement errors and identifying potential malfunctions, ensuring accurate and efficient battery manufacturing by determining temperature responses and internal resistance values.

Implementation Method 1

measuring temperatures of the measuring spots with the temperature sensors, creating a measuring spot specific temperature response based on temperatures measured in the corresponding measuring spot

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

heating up the busbar

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4421488A1Method and arrangement for defining quality of busbar weldings
Publication Date: 2024.08.28 IONCOR LTD
  • EP4421488A1 patent drawingFigure 1~2
  • EP4421488A1 patent drawingFigure 3~4
  • EP4421488A1 patent drawingFigure 5~6

AI summary

A method and an arrangement for defining the quality of busbar weldings, the method comprising - providing (500) a holder (1) that comprises a set of temperature sensors (2). The temperature sensors (2) being arranged to a predetermined pattern (3) according to the welding spots (4) in the busbar (5). Placing (501) the holder (1) on the busbar (5) welded to terminals (6) of battery cells and pressing (502) the temperature sensors (2) by a contacting force against the busbar (5) so that they make a contact with the busbar (5) in measuring spots (7), heating up (503) the busbar (5), measuring (504) temperatures of the measuring spots (7) with the temperature sensors (2), creating (505) a measuring spot specific temperature response based on temperatures measured in the corresponding measuring spot, and defining (506) the welding quality of the welding spot (4) based on the measuring spot specific temperature response of the nearest measuring spot (7).