Battery Pack PCM with Integrated PTC Safety Device
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Solution Overview
Problem
Lithium secondary batteries face safety concerns due to the risk of overheating and explosion from overcharge, overcurrent, or external impacts, which existing safety measures like PTC elements and chemical additives fail to adequately address, leading to reduced safety and performance.
Innovation Solution
A battery pack design incorporating a protection circuit module (PCM) with a safety device that automatically disconnects the circuit when temperature rises or excessive current flows, utilizing a PTC element directly attached to the PCM without additional connection members, and a conductive pattern on the PCB for overcurrent interruption, minimizing internal space and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PTC element and safety device are mounted outside the cell with additional connection members, then safety protection is provided, but the internal space of the battery is reduced and assembly complexity increases
Solution Approach 1:
The safety device is merged with the protection circuit module (PCM) by directly attaching the PTC element to the PCM circuit board. This integration eliminates the need for separate mounting structures and connection members, thereby preserving battery internal space while maintaining safety protection functionality.
Solution Approach 2:
The protection circuit module serves multiple functions: it provides safety protection through the PTC element, performs circuit control, and eliminates the need for separate mounting structures. By making the PCM multi-functional, the design reduces overall component count and space requirements while maintaining comprehensive safety protection.
2Reliability
If a PTC element is connected to the PCM using additional connection members, then electrical connection is established, but assembly complexity and manufacturing difficulty increase
Solution Approach 1:
The PTC element is directly attached to the PCM circuit board, merging two previously separate components into a single integrated assembly. This eliminates the need for additional connection members and simplifies the manufacturing process while ensuring reliable electrical connection between the PTC element and the protection circuit.
3Reliability
If safety devices are added to protect against overcharge and overcurrent, then battery safety is improved, but the device complexity increases
Solution Approach 1:
Multiple safety functions (overcharge protection, overcurrent protection) are merged into a single protection circuit module. The PTC element is directly integrated with the PCM circuit board, combining what would traditionally be separate safety devices into one unified component, thereby reducing overall device complexity while maintaining comprehensive safety protection.
Solution Approach 2:
The protection circuit module is designed as a multi-functional device that provides both overcharge and overcurrent protection through integrated circuits and the PTC element. This universal design approach allows a single component to perform multiple safety functions, reducing the need for separate dedicated safety devices and thereby simplifying the overall system.
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 design enhances the safety and volume density of the battery pack by preventing short circuits, reducing assembly complexity, and ensuring efficient current interruption during abnormal conditions, thereby preventing overheating and explosions.
Implementation Method 1
a positive temperature coefficient (PTC) element and a circuit interruption device (CID) element using the change in temperature of the battery
Implementation Method 2
the battery is heated due to IR heat generation
Data Source
AI summary
A battery pack including a battery cell having an electrode assembly of a cathode/separator/anode structure mounted in a battery case together with an electrolyte in a sealed state, and a protection circuit module (PCM) electrically connected to the battery cell. The PCM includes a protection circuit board (PCB) electrically connected to the battery cell, the PCB being provided on a region where a circuit is connected with a conductive pattern including a fusing part, having relatively high resistance, configured to fuse itself for interrupting the flow of current when a large amount of current is conducted.