Plated FPCB Sealing in Pouch Battery Cells to Prevent Leakage

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Solution Overview

Problem

Existing technologies fail to stably fix a flexible printed circuit board through the sealed portion of a pouch-shaped battery cell, leading to reduced sealing strength and potential electrolyte leakage, compromising the safety and integrity of the battery.

Innovation Solution

A flexible printed circuit board with a plating portion on its outer surface, plated with gold or nickel, is used to increase adhesion, combined with a thermal bonding film made of polypropylene-based material, to enhance sealing strength at the sealed portion of the pouch-shaped battery cell.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pouch-type battery cell uses a rigid printed circuit board (PCB) for electrical connection, then electrical connection stability is improved, but the battery cell cannot accommodate volume changes during charging and discharging

Engineering Contradiction:

Improveelectrical connection stabilityVSAvoidaccommodation of volume changes

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the rigid PCB with a flexible printed circuit board (FPCB) that has bendable characteristics. This FPCB can elastically deform to accommodate the volume expansion and contraction of the battery pouch during charging and discharging cycles, while still maintaining stable electrical connections between the electrode groups and the external circuitry.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the physical parameter of the circuit board from rigid to flexible. By using an FPCB with appropriate flexibility parameters, the circuit board can dynamically adjust its shape and position to match the changing volume of the battery pouch, thereby resolving the contradiction between connection stability and volume adaptability.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If a pouch-type battery cell uses a flexible printed circuit board (FPCB) to accommodate volume changes, then adaptability to volume changes is improved, but connection stability may be compromised

Engineering Contradiction:

Improveaccommodation of volume changesVSAvoidconnection stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The FPCB is designed with specific flexibility characteristics that allow it to elastically deform with the battery pouch volume changes while maintaining sufficient mechanical strength to preserve stable electrical connections. The flexible nature enables volume accommodation, while the printed circuit traces maintain electrical integrity throughout the deformation process.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The FPCB employs composite material construction that combines flexible substrates with conductive trace materials. This composite structure provides both the flexibility needed for volume adaptation and the electrical conductivity required for stable connections, resolving the apparent contradiction between flexibility and connection reliability.

Inventive Principle:

Principle #40Composite materials

3Quantity of substance

If the battery pouch volume is increased to improve energy storage capacity, then energy storage capacity is improved, but internal stress and risk of damage increase

Engineering Contradiction:

Improveenergy storage capacityVSAvoidinternal stress and damage risk

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The FPCB acts as a flexible intermediary that can accommodate the volume expansion of larger battery pouches during charging. By elastically deforming with the pouch, the FPCB reduces internal stress concentrations that would otherwise occur at rigid connection points, thereby lowering the risk of damage while supporting higher energy storage capacities.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The flexible nature of the FPCB provides a cushioning effect that absorbs and distributes the internal stress generated during battery pouch expansion. This preemptive stress distribution prevents localized stress concentrations that could lead to damage, enabling safer operation of high-capacity battery pouches.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP4307450B1Pouch-shaped battery cell including flexible printed circuit board

Publication Date: 2026.04.29 LG ENERGY SOLUTION LTD

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AI summary

The present invention relates to a pouch-shaped battery cell including a flexible printed circuit board (FPCB) having a circuit layer disposed at one surface or each of opposite surfaces thereof, wherein the flexible printed circuit board includes a plating portion having plating formed thereon disposed at the outermost surface of the part of the flexible printed circuit board that abuts a sealed portion at which a pouch-shaped battery case is sealed. It is possible to secure the strength of sealing of the flexible printed circuit board to the sealed portion of the pouch-shaped battery case as the result of formation of the plating portion.