Flexible PCB Pressure Sensing for Sealed Pouch Cells

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Solution Overview

Problem

Existing methods fail to accurately measure internal pressure changes in pouch cells due to difficulties in inserting a pressure sensor, leading to potential safety issues like explosion from increased gas pressure.

Innovation Solution

A flexible printed circuit board with a pressure sensor and protective sheath is designed to be inserted into pouch cells, featuring a sensing part, extension part, and board part, with a waterproof MEMS pressure sensor and parylene coating to prevent damage during sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a pressure sensor is inserted into a pouch cell to measure internal pressure, then measurement precision is improved, but the device complexity increases and ease of manufacture deteriorates

Engineering Contradiction:

Improveinternal pressure measurementVSAvoidsensor insertion structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the pressure sensor with the flexible printed circuit board into an integrated assembly. The sensor is mounted on the FPCB, merging the measurement function with the structural component, thereby reducing overall device complexity while maintaining measurement precision.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a flexible printed circuit board as a thin, flexible substrate to mount the pressure sensor. This flexible structure can be easily inserted into the pouch cell through the sealing edge without requiring complex insertion mechanisms, thus reducing device complexity while enabling accurate pressure measurement.

Inventive Principle:

Principle #30Flexible shells and thin films

2Ease of operation

If a flexible printed circuit board is inserted into a pouch cell for sensor mounting, then ease of operation is improved, but manufacturing precision deteriorates due to cutting and conductor damage during heat-welding

Engineering Contradiction:

Improvesensor insertionVSAvoidconductor pattern integrity

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent introduces a protective sheath as an intermediary layer between the flexible printed circuit board and the heat-welding process. This sheath protects the conductor patterns from direct exposure to heat and mechanical stress during sealing, preventing damage while allowing the FPCB to be easily inserted and welded into the pouch cell.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective sheath is applied to the FPCB before insertion and heat-welding operations. This preliminary protective measure prevents conductor damage during subsequent manufacturing steps, ensuring manufacturing precision is maintained while preserving the ease of operation benefits.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the flexible printed circuit board is heat-welded to seal the pouch cell, then productivity is improved, but reliability deteriorates due to conductor pattern damage and communication failure

Engineering Contradiction:

Improvesealing speedVSAvoidelectrical communication

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The protective sheath serves as a mediator that allows rapid heat-welding sealing while protecting the electrical conductor patterns from damage. This enables high-speed sealing operations to proceed without compromising the reliability of electrical communication through the FPCB.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective sheath provides beforehand cushioning and protection to the conductor patterns against heat and mechanical stress during the heat-welding process. This prior protection ensures that even during fast sealing operations, the electrical pathways remain intact and reliable.

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

Enables accurate measurement of internal pressure in pouch cells without functional issues, enhancing safety by preventing sensor damage and ensuring reliable sealing.

Implementation Method 1

a protective sheath of a metal material that surrounds an outer surface of an insulating film in a predetermined section

Methodology Applied

Scientific EffectThermal protection:

Implementation Method 2

respective edges of the two pouch sheets are heat-welded and sealed

Methodology Applied

Scientific EffectHeat-welding:

Implementation Method 3

a pressure sensor mounted on a sensing part

Methodology Applied

Scientific EffectPressure sensing:

Data Source

PatentUS12537235B2Flexible printed circuit board for measuring internal pressure of pouch cell, and method of measuring internal pressure of pouch cell

Publication Date: 2026.01.27 LG ENERGY SOLUTION LTD

AI summary

A flexible printed circuit board for pouch cell internal pressure measurement includes a sensing part on which a pressure sensor is mounted; a board part provided with connector pins connected to a plurality of conductor lines, respectively; and an extension part extending from the sensing part to the board part. The extension part includes a protective sheath of a metal material that surrounds an outer surface of an insulating film in a predetermined section.