Fusible Bimetallic Bus Bars for Battery Short Circuit Protection

The bus bar is constructed from two dissimilar metals with different melting points (e.g., aluminum and copper). The lower-melting-point metal forms a fusible section that acts as a protective element, while the higher-melting-point metal provides structural integrity and electrical conductivity. This composite structure enables the bus bar to provide both reliable electrical connectivity and automatic short circuit protection through controlled melting at the fusible section.

The bus bar is divided into distinct sections: a first section made of a higher-melting-point metal, a second fusible section made of a lower-melting-point metal, and a third section made of the higher-melting-point metal. This segmentation allows each section to be optimized for its specific function (structural, protective, structural) and facilitates manufacturing processes such as separate casting or joining of the dissimilar metals, thereby reducing overall manufacturing complexity despite the bimetallic construction.

The design exploits the parameter difference in melting points between the two dissimilar metals. By selecting materials with sufficiently different melting points (e.g., aluminum at 660°C and copper at 1085°C), the fusible section melts preferentially during a short circuit event while the structural sections remain intact. This parameter-based differentiation simplifies the joining requirements, as the metals can be connected using standard welding or brazing techniques without requiring specialized dissimilar-metal joining processes throughout the entire structure.