RESISTANCE WELDING OF THERMOPLASTIC COMPOSITE AUTOMOTIVE BATTERY TRAY
Topic(s) : Manufacturing
Co-authors :
Soraya PINTOS (SPAIN), Massimiliano RUSELLO , Paula RODRÍGUEZ (SPAIN), Alba PEÑA (SPAIN), Laura MERA , Luis CARRALAbstract :
Vehicle’s electrification is proposed as key point to achieve global legislative requirements for CO2 emission reductions. However, several issues currently limit further exploitation. Specifically, concerns of drivers regarding battery range, cost, the long-term reliability of batteries and the excessive charging times.
ALBATROSS project is based on the development of a BMW i3 electric vehicle (EV), on the basis of a modular concept equally applicable to Battery Electric Vehicles (BEVs) and Plug-in Hybrid Electric Vehicles (PHEVs) for all passenger car applications. The principal aim of ALBATROSS is to create advanced battery pack designs and achieve a 20% weight reduction of the battery system equal to 56 Kg weight reduction. The expected final battery weight is 222 Kg (currently 278 Kg), through a combination of light-weighting approaches, reduction of batteries number and removal of auxiliary components. For this purpose, a new design in composite material have been done to lightweight the battery tray.
Nowadays, the battery case of electric vehicles is manufactured completely with metal parts and the innovation in ALBATROSS is change certain metal components by composite materials. In the case of the battery tray, different parts are modified with this purpose. In this study, the top cover component is addressed, where a completely redesign of the component has been done, manufacturing the entire top cover in composite material.
The top cover component selected material was a comingled nonwoven fabric made with recycled carbon fibres with polyamide 6 (PA6) resin, manufactured trough hot press consolidation. As the mechanical requirements are not too high, a short fibre composite can be used. The assembly of these components have been performed through adhesive joining, but one of the demonstrators was manufactured and assembled by thermoplastic composite welding, using the resistance welding technique, in order to validate this type of joint strategy. In this work, the welding strategy and all the steps involved have been analysed, from electrical heating element characterization to medium scale components assembly (welding a 500 x 25 mm2 surface), going through laboratory welding window optimization and characterization of the weld. The welds have been analysed mechanically by single lap shear test (through AITM1-0019 standard) and macro and microscopic images. The characterization results have been compared with the obtained ones with the same adhesive bonded joints.
ALBATROSS project is based on the development of a BMW i3 electric vehicle (EV), on the basis of a modular concept equally applicable to Battery Electric Vehicles (BEVs) and Plug-in Hybrid Electric Vehicles (PHEVs) for all passenger car applications. The principal aim of ALBATROSS is to create advanced battery pack designs and achieve a 20% weight reduction of the battery system equal to 56 Kg weight reduction. The expected final battery weight is 222 Kg (currently 278 Kg), through a combination of light-weighting approaches, reduction of batteries number and removal of auxiliary components. For this purpose, a new design in composite material have been done to lightweight the battery tray.
Nowadays, the battery case of electric vehicles is manufactured completely with metal parts and the innovation in ALBATROSS is change certain metal components by composite materials. In the case of the battery tray, different parts are modified with this purpose. In this study, the top cover component is addressed, where a completely redesign of the component has been done, manufacturing the entire top cover in composite material.
The top cover component selected material was a comingled nonwoven fabric made with recycled carbon fibres with polyamide 6 (PA6) resin, manufactured trough hot press consolidation. As the mechanical requirements are not too high, a short fibre composite can be used. The assembly of these components have been performed through adhesive joining, but one of the demonstrators was manufactured and assembled by thermoplastic composite welding, using the resistance welding technique, in order to validate this type of joint strategy. In this work, the welding strategy and all the steps involved have been analysed, from electrical heating element characterization to medium scale components assembly (welding a 500 x 25 mm2 surface), going through laboratory welding window optimization and characterization of the weld. The welds have been analysed mechanically by single lap shear test (through AITM1-0019 standard) and macro and microscopic images. The characterization results have been compared with the obtained ones with the same adhesive bonded joints.