Flexible Printed Circuit Board Protection Module for Ultra-Thin Battery Design

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Solution Overview

Problem

Conventional protection circuit modules for secondary batteries are limited in miniaturization due to the thickness of printed circuit boards, which hinders the reduction in size of portable electronic devices powered by these batteries.

Innovation Solution

A thin protection circuit module using a flexible printed circuit board with control circuitry and switching devices, where the control circuitry is mounted via adhesive material, and the entire assembly is encapsulated with a protector, maintaining electrical insulation and reducing overall thickness to 0.5 mm or less.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional printed circuit board is used for the protection circuit module, then the circuit devices can be mounted and electrically connected, but the thickness becomes at least 0.5 mm which limits further miniaturization

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidmodule thickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The patent replaces the conventional rigid printed circuit board with a flexible printed circuit board (FPCB) that has a thickness of 0.1 mm or less. This thin film structure maintains the electrical connection function while dramatically reducing the thickness from at least 0.5 mm to 0.1 mm or less, enabling further miniaturization of the protection circuit module.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the thickness parameter of the circuit board from the conventional 0.5 mm minimum to 0.1 mm or less by using FPCB technology. This parameter change allows the module to achieve ultra-thin profile while maintaining all necessary electrical connection functions through the flexible board structure.

Inventive Principle:

Principle #35Parameter changes

2Length of stationary object

If the module thickness is reduced to enable miniaturization, then portable electronic devices can be smaller, but the safety protection of circuit devices may be compromised

Engineering Contradiction:

Improvemodule thicknessVSAvoidcircuit device safety

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

The patent uses a protector that encapsulates the control circuitry mounted on the FPCB, creating a nested structure where the thin FPCB is protected within a protective housing. This nesting approach provides safety protection for the circuit devices while maintaining the overall thin profile of the module.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The protector encapsulating the control circuitry provides beforehand cushioning and protection against physical damage, environmental factors, and electrical interference. This protective structure is built in advance to ensure circuit device safety while maintaining the ultra-thin design.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP2169757B1Protection circuit module and secondary battery including the protection circuit module

Publication Date: 2015.08.26 SAMSUNG SDI CO LTD

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AI summary

A protection circuit module (PCM) (120) for a secondary battery (100) including a bare cell (110). The PCM (120) includes: a flexible printed circuit board (FPCB) (121); and control circuitry (126, 127) mounted on the FPCB (121) via adhesive material and configured for electrical coupling to the bare cell (110) through the FPCB (121). The control circuitry (126, 127) is adapted to control charging and discharging of the bare cell (110).