Abstract
Recent uptake in the use of lithium-ion battery packs within electric vehicles has drawn significant attention to the selection of busbar material and corresponding thickness, which are usually based on mechanical, electrical and thermal characteristics of the welded joints, material availability and cost. To determine joint behaviour corresponding to critical-to-quality criteria, this study uses one of the widely used joining technologies, ultrasonic metal welding (UMW), to produce tab-to-busbar joints using copper and aluminium busbars of varying thicknesses. Joints for electrical and thermal characterisation were selected based on the satisfactory mechanical strength determined from the T-peel tests. Electrical contact resistance and corresponding temperature rise at the joints were compared for different tab-to-busbar joints by passing current through the joints. The average resistance or temperature increase from the 0.3 mm Al tab was 0.6 times higher than the 0.3 mm Cu[Ni] tab, irrespective of busbar selection.
Highlights
Lithium-ion (Li-ion) electrochemistry-based secondary batteries are widely used for electrification of automotive vehicles due to several advantages, including high energy density, low self-discharge and portability [1,2]
To assist in meeting emission legislation, automotive manufacturers are moving towards lightweight applications, intelligent automation or adapting new powertrain technology based on hybrid or pure secondary batteries
Based on the module design, a number of pouch cells are to be connected within a module and several modules are arranged in a battery pack or storage unit
Summary
Lithium-ion (Li-ion) electrochemistry-based secondary batteries are widely used for electrification of automotive vehicles due to several advantages, including high energy density, low self-discharge and portability [1,2]. The widely used pouch cell format uses a tab-to-busbar connection as the electrical interconnect. A large number of tab-to-busbar joints are inevitable, and each must provide electrically and thermally suitable connections in which vehicles are often exposed to harsh driving conditions [7]. The busbar plays an important role in providing desired electrical and thermal characteristics combined with mechanical strengths. The selection of busbar material and its thickness are largely based on the current carrying capacity, mechanical and electrical characteristics and cost [8]. Busbar material and thickness play a vital role in avoiding excessive heat generation at the tab-to-busbar interconnects
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