Pouch Battery Cell Busbar Joining to Cut Resistance and Heat

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Solution Overview

Problem

Conventional battery modules experience high internal resistance due to multiple welding points in the electrical connections between electrode tabs, electrode leads, and busbars, leading to voltage measurement errors and heat generation issues, particularly in high-output applications.

Innovation Solution

A battery cell design with protrusions on the electrode current collectors that are directly welded to busbars, eliminating the need for electrode leads and incorporating mechanical fastening methods for busbar connections, such as bolt, rivet, or clinching, to reduce resistance and improve design flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional welding methods are used to connect electrode leads to busbars through multiple connection points, then electrical connection is achieved, but internal resistance increases and heat generation occurs

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidinternal resistance and heat generation

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent removes the electrode lead from the connection path between the electrode tab and busbar. By directly welding the electrode tab to the busbar, the intermediate electrode lead is extracted from the system, eliminating the additional welding points and reducing internal resistance while maintaining electrical connection reliability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the electrode tab and busbar connection by eliminating the intermediate electrode lead. The electrode tab is directly welded to the busbar, combining what were previously separate components (electrode tab-electrode lead-busbar) into a direct connection (electrode tab-busbar), thereby reducing the number of welding points and internal resistance

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If multiple welding points are used for electrical connections between electrode tabs, electrode leads, and busbars, then electrical connection is established, but manufacturing complexity and time increase

Engineering Contradiction:

Improveelectrical connectionVSAvoidassembly time and manufacturing efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The electrode lead is removed from the assembly process. Instead of welding electrode tabs to electrode leads and then welding electrode leads to busbars, the patent directly welds electrode tabs to busbars, extracting the intermediate component and reducing the number of welding operations from two to one

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent combines the electrode tab and busbar into a direct welding operation, eliminating the need for separate welding steps for electrode tab-to-electrode lead and electrode lead-to-busbar connections. This merging of components reduces manufacturing steps and improves productivity

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If electrode leads are used for electrical connections, then flexibility in connection methods is maintained, but internal resistance and voltage measurement errors increase

Engineering Contradiction:

Improveconnection method flexibilityVSAvoidvoltage measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The electrode lead is extracted from the electrical connection path. By directly welding the electrode tab to the busbar, the patent eliminates the intermediate electrode lead that caused voltage measurement errors due to additional contact resistance and welding point variability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the electrode tab and busbar connection points, eliminating the intermediate electrode lead. This direct connection reduces the total resistance and minimizes voltage measurement errors by reducing the number of interfaces and contact points in the electrical path

Inventive Principle:

Principle #5Merging (Combining)

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

Reduces internal resistance, minimizes voltage measurement errors, and decreases heat generation during charging and discharging, while offering easier reworkability and design freedom compared to conventional welding methods.

Implementation Method 1

a busbar is joined to the protrusion

Methodology Applied

Scientific EffectWelding: Welding

Data Source

PatentUS20260045647A1Battery Cell and Battery Module Including the Same

Publication Date: 2026.02.12 LG ENERGY SOLUTION LTD

AI summary

A battery cell includes an electrode assembly and a pouch case. The electrode assembly includes electrodes and a separator located between the electrodes and the pouch case has an outer peripheral side sealed in a state where the electrode assembly is housed inside. The electrode includes an electrode current collector with an active material layer formed on one side or both sides of the electrode current collector and a protrusion formed such that a part of the electrode current collector protrudes to the outside of the sealed pouch case. A busbar is joined to the protrusion.