Battery Pack Connecting Bar With Low-Melting Metal Bridge
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Solution Overview
Problem
Existing battery packs face safety concerns due to potential explosions caused by overheating, particularly when an overcurrent occurs, as existing protection circuits can malfunction, leading to inadequate disconnection of the current and inefficient spatial use.
Innovation Solution
A battery pack design featuring a connecting bar with a lead-free alloy metal bridge, made of tin and copper, having a lower melting point than the metal plates, which rapidly breaks when overheating occurs, ensuring safety by interrupting the current flow and preventing explosions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection circuit with fuse element and microcontroller is used to protect against overcurrent, then battery safety is improved, but device complexity and spatial requirements increase
Solution Approach 1:
The invention extracts the safety protection function from the complex electronic protection circuit (fuse element and microcontroller) and implements it through the inherent thermal properties of the metal bridge material. The metal bridge automatically melts at a predetermined temperature to disconnect the circuit, eliminating the need for additional protection components while maintaining safety.
Solution Approach 2:
The metal bridge performs self-protection by automatically melting when the battery temperature reaches the predetermined level. This self-activating mechanism does not require external control signals or power supply, thereby simplifying the overall device structure while ensuring reliable safety protection.
2Reliability
If a metal bridge with lower melting point is used in the connecting bar, then safety against overheating is improved, but the connecting bar strength is reduced
Solution Approach 1:
The invention applies local quality by creating a metal bridge with distinct thermal properties (lower melting point) at a specific location within the connecting bar structure. The bridge portion has different material composition or structure compared to the main connecting bar, allowing it to melt at lower temperature while the main bar retains its structural strength.
Solution Approach 2:
The connecting bar employs composite material structure where the metal bridge is formed from materials with different thermal characteristics than the main bar body. This composite approach allows the bridge to sacrifice at predetermined temperature while the main connecting structure maintains its mechanical integrity and strength.
3Reliability
If the connecting bar is designed to break at predetermined temperature, then safety is improved, but the durability under normal operation may be compromised
Solution Approach 1:
The invention carefully selects and controls the melting temperature parameter of the metal bridge material to ensure it is significantly higher than the normal operating temperature range of the battery. This parameter optimization allows the bridge to maintain structural integrity during normal use while still providing safety protection when abnormal overheating occurs.
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 effectively ensures safety by rapidly breaking the connecting bar during overcurrent events, preventing overheating-induced explosions and improving spatial efficiency by eliminating the need for a separate fuse element and microcontroller.
Implementation Method 1
at least one of the connecting bars includes a first metal plate; a second metal plate spaced apart from the first metal plate; and a metal bridge configured to connect the first metal plate and the second metal plate and having a lower melting point than the metal plate
Implementation Method 2
If an overcurrent flows, the lithium secondary battery generates Joule's heat and thus an internal temperature of the battery rapidly increases
Data Source
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AI summary
A battery pack includes a plurality of battery modules, each having at least one unit cell, a case for accommodating the unit cell and a bus bar electrically connected to the unit cell, and a connecting bar for connecting battery modules adjacent to each other among the plurality of battery modules, wherein at least one of the connecting bars includes a first metal plate, a second metal plate spaced apart from the first metal plate, and a metal bridge configured to connect the first metal plate and the second metal plate and having a lower melting point than the metal plate. In this configuration, if an overcurrent flows at the battery pack, the connecting bar is easily broken, thereby ensuring safety of the battery pack in use.