Flexible Substrate Battery Protection Circuit Package
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Solution Overview
Problem
Lithium-ion batteries face issues with heat generation during overcharging and overcurrent conditions, leading to performance degradation and explosion risks, necessitating improved battery protection circuits that enhance operation speed and heat radiation properties.
Innovation Solution
A battery protection circuit package is developed using a flexible substrate coupled with a lead frame and printed circuit board (PCB) configuration, incorporating surface mounting technology, underfilling with epoxy, and encapsulation with a molding material, while exposing input/output terminals and metal tabs for external connection, and bonding flexible printed circuit boards (FPCBs) for improved heat dissipation and reduced resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a rigid substrate is used in battery protection circuit, then structural stability is maintained, but operation speed and heat radiation properties are limited due to higher resistance
Solution Approach 1:
The patent changes the substrate parameter from rigid to flexible, which fundamentally alters the electrical and thermal properties. The flexible substrate exhibits lower resistance characteristics that enable faster signal propagation (improved operation speed) and better thermal conduction (improved heat radiation properties), directly resolving the contradiction between speed and reliability.
Solution Approach 2:
The patent employs a composite structure combining flexible substrate material with conductive traces and protective encapsulation. This composite approach allows optimization of electrical conductivity and thermal radiation independently, achieving high operation speed while maintaining structural integrity and heat dissipation capability.
2Reliability
If flexible substrate is used to improve operation speed and heat radiation, then resistance is lowered, but structural stability and manufacturing complexity increase
Solution Approach 1:
The patent divides the battery protection circuit into modular components: flexible substrate, circuit traces, encapsulation layer, and connection terminals. This segmentation allows each component to be optimized and manufactured separately using specialized processes, then assembled into the final product, reducing overall manufacturing complexity despite the advanced materials used.
Solution Approach 2:
The patent introduces an encapsulation material as an intermediary between the flexible substrate and the external environment. This encapsulation layer protects the flexible circuit from mechanical damage and environmental factors, enabling the use of flexible materials without compromising structural stability or manufacturing feasibility.
3Reliability
If battery protection circuit is added to prevent overcharging and overcurrent, then battery safety is improved, but device complexity and fabrication cost increase
Solution Approach 1:
The flexible substrate serves multiple functions simultaneously: it provides the mechanical support structure, acts as the electrical connection medium through integrated traces, and enables thermal management through its heat radiation properties. This multi-functionality consolidates what would otherwise require separate components, reducing overall device complexity while maintaining battery safety features.
Solution Approach 2:
The patent merges the circuit board function, connection terminal function, and heat dissipation function into a single integrated flexible substrate structure. By combining these functions that traditionally required separate components, the design reduces structural complexity and fabrication cost while preserving all necessary safety and operational features.
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 solution enables high-speed operation and superior heat radiation properties, reducing internal resistance and fabrication costs, while enhancing the stability and safety of lithium-ion batteries by minimizing thickness and improving thermal conductivity.
Implementation Method 1
forming an encapsulation structure by encapsulating the second mounting structure with a molding material to encapsulate at least a part of the battery protection circuit elements
Implementation Method 2
bonding at least one flexible printed circuit board (FPCB) to the input/output terminal portion of the encapsulation structure... superior heat radiation properties... improving thermal conductivity
Implementation Method 3
a lead frame configured to comprise an input/output terminal portion for external connection and at least one metal tab for battery cell connection
Data Source
AI summary
A method of fabricating a battery protection circuit package according to one aspect of the present invention includes forming a first mounting structure by mounting battery protection circuit elements on a printed circuit board (PCB), forming a second mounting structure by mounting the first mounting structure on a lead frame which comprises an input/output terminal portion for external connection and at least one metal tab for battery cell connection, forming an encapsulation structure by encapsulating the second mounting structure with a molding material to encapsulate at least a part of the battery protection circuit elements while exposing the input/output terminal portion and the at least one metal tab of the lead frame, and bonding at least one flexible printed circuit board (FPCB) to the input/output terminal portion of the encapsulation structure.