Battery Module Sensing Terminal Welding for Stronger Busbar Joints

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Solution Overview

Problem

The challenge of enhancing weld strength between the sensing terminal unit and the busbar, ensuring close contact during welding, and reducing spatter dispersion in battery modules, particularly in the limited size of the sensing terminal unit, is addressed.

Innovation Solution

A battery module design with a sensing terminal unit that includes a coupling portion and multiple welding regions arranged in a grid or polygonal pattern, along with a welding jig to ensure proper contact and prevent spatter dispersion during welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If seam welding is used to connect sensing terminal unit and busbar, then electrical connection is achieved, but weld strength is relatively lower due to dissimilar metals and narrow weld bead width

Engineering Contradiction:
Improveelectrical connectionVSAvoidweld strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent divides the welding connection into multiple discrete welding regions (first welding region, second welding region, third welding region) instead of a single continuous seam weld. This segmentation allows each region to be optimized independently and distributes stress across multiple points, preventing stress concentration that occurs in traditional seam welding.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different welding approaches to different local regions of the sensing terminal unit. Each welding region has specific dimensional requirements (width, length, spacing) tailored to its position and function. The welding beads are formed with controlled dimensions (width greater than height) to optimize local stress distribution and connection strength.

Inventive Principle:
Principle #3Local quality

2Strength

If weld length is increased to improve weld strength, then connection strength improves, but the limited size of sensing terminal unit makes increasing weld length difficult

Engineering Contradiction:
Improveweld strengthVSAvoidsensing terminal unit size
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The patent extracts the welding connection from a single continuous seam and separates it into multiple discrete welding regions. This allows the welding connection to extend across the available surface area of the sensing terminal unit without requiring an increase in the overall unit size. The welding regions are positioned at strategic locations to maximize connection strength within the constrained footprint.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transitions from a one-dimensional seam weld to a two-dimensional distribution of multiple welding regions across the sensing terminal unit surface. By arranging welding regions in different positions (first, second, third regions) with specific spacing relationships, the effective welding area is expanded without increasing the dimensional footprint of the terminal unit itself.

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

3Strength

If multiple welding regions are created to enhance weld strength, then connection strength improves, but ensuring close contact between sensing terminal unit and busbar during welding becomes more challenging

Engineering Contradiction:
Improveweld strengthVSAvoidcontact precision during welding
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent incorporates a coupling portion on the sensing terminal unit that is specifically designed to pre-align and pre-contact with the busbar before welding begins. This preliminary mechanical coupling ensures that all welding regions are properly positioned and that close contact is established across all welding points before the welding process starts, eliminating alignment issues during welding.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The coupling portion acts as an intermediary element between the sensing terminal unit and the busbar. It provides a mechanical interface that ensures proper positioning and contact between the two components, facilitating accurate alignment for multiple welding regions without requiring complex welding fixtures or precision positioning systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If welding is performed to connect sensing terminal unit and busbar, then electrical connection is established, but spatter scattering occurs during welding

Engineering Contradiction:
Improveelectrical connectionVSAvoidspatter scattering
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the potentially harmful spatter scattering into a beneficial feature by designing the welding regions to produce welding beads with controlled morphology. The welding beads are formed with width greater than height and are positioned to overlap or closely adjacent to each other, creating a consolidated weld profile that contains spatter rather than allowing it to scatter. The spatter becomes part of the weld bead structure, contributing to the overall connection integrity.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 design enhances weld strength, enabling the battery module to withstand bending, torsion, and twist forces while ensuring stable voltage measurement and preventing damage from external impacts.

Implementation Method 1

the sensing terminal unit may include a coupling portion positioned to face at least a portion of the busbar and a plurality of welding regions connecting the coupling portion and the sensing terminal unit

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP4715997A1Battery module and assembly method therefor
Publication Date: 2026.03.25 SK ON CO LTD
  • EP4715997A1 patent drawingFigure 1
  • EP4715997A1 patent drawingFigure 2
  • EP4715997A1 patent drawingFigure 3

AI summary

The present disclosure relates to a battery module and an assembly method therefor, the battery module comprising: a plurality of battery cells stacked in one direction; a busbar electrically connected to the plurality of battery cells stacked in the one direction; a sensing unit electrically connected to the busbar in order to detect the voltage of the plurality of battery cells; and a sensing terminal unit provided between the sensing unit and the busbar so as to electrically connect the busbar and the sensing unit. The sensing terminal unit comprises: a coupling unit positioned so as to face at least a portion of the busbar; and a plurality of welding regions for coupling the coupling unit and the sensing terminal unit when the sensing terminal unit and the busbar are welded.