Battery Pack FPC Solder Joint for Durable Cell Supervision Connection
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Solution Overview
Problem
The durability of the electrical connection between a flexible printed circuit and a cell supervision circuit in rechargeable battery packs is compromised due to frequent damage from connector attachment and detachment, leading to potential disconnection.
Innovation Solution
The connection between the flexible printed circuit and the cell supervision circuit is established using electrically conductive solder instead of a connector, with conductive pad portions and a solder application method that maximizes the connection area and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a connector is used to electrically connect the flexible printed circuit and the cell supervision circuit, then the connection can be easily assembled and disassembled, but the durability of the electrical connection deteriorates due to frequent attachment and detachment causing circuit damage
Solution Approach 1:
The patent extracts the connector component from the electrical connection system and replaces it with a soldered connection. By removing the connector, the source of mechanical stress and connection failure is eliminated, while the soldered joint provides permanent reliable electrical connection between the FPC and cell supervision circuit.
Solution Approach 2:
The patent merges the electrical connection function directly into the circuit board structure through soldering, combining the FPC trace, pad, and cell supervision circuit into a unified soldered assembly. This integration eliminates the separate connector component and creates a more robust electrical connection.
2Ease of repair
If the connector is frequently attached and detached for maintenance or replacement, then the adaptability and ease of repair are improved, but the circuit connected to the connector becomes frequently damaged
Solution Approach 1:
The patent applies beforehand cushioning by designing the FPC with expanded pad portions that protrude from the circuit line. These expanded pads provide a larger soldering surface area and create a more robust mechanical anchor point, cushioning the connection against mechanical stresses that would otherwise damage the circuit during maintenance operations.
Solution Approach 2:
The patent implements preliminary action by pre-expanding the pad portions of the FPC before soldering. The expanded pads are formed in advance with greater surface area and protrusion, preparing the connection interface to withstand future mechanical stresses and ensuring durable solder attachment before any maintenance or replacement operations occur.
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
This method prevents disconnection due to pressurized damage, ensuring a stable and durable electrical connection between the circuits.
Implementation Method 1
The flexible printed circuit is electrically connected to the cell supervision circuit by an electrically conductive solder
Implementation Method 2
The electrically conductive solder may be a cream solder applied to the first step side, the second step side, and the round groove, may be bonded by laser heat
Implementation Method 3
The electrically conductive solder may be a cream solder applied to the first step side, the second step side, and the round groove, may be bonded by laser heat, and may be electrically connected to the cell supervision circuit
Data Source
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AI summary
A rechargeable battery pack according to an embodiment includes: a cell assembly including at least one battery cell; a side frame accommodating the cell assembly; a flexible printed circuit (FPC) electrically connected to the cell assembly and configured to sense at least one property of the battery cell; and a cell supervision circuit electrically connected to the flexible printed circuit and on one side of the side frame. The flexible printed circuit is electrically connected to the cell supervision circuit by an electrically conductive solder.