The on-going dynamism in the electrification of vehicles requires radical changes in mobility, automotive industries and significant part of the mechanical engineering sector. All global players in the automotive industry are making great efforts to develop cost-efficient electric drives, suitable for series production. The manufacturing processes of electric vehicles benefit from innovative laser production systems: both in terms of efficiencies in time, space and productivity and in terms of quality, automatability and repeatability. Although the interest of the scientific world in this field is continuously arising, there is no trace of a thorough and systematic analysis concerning the whole set of laser applications in the world of electric vehicles production. In this thesis is presented a deep analysis of the current scientific and industrial state of the art about laser-based manufacturing applied in electric vehicle production, allowing a systematic and methodical analysis of the processes, of their strengths and weaknesses. The survey highlights a new sector requiring innovative technological solutions, and some challenges: tricky-processing materials such as copper, high productivity, no defects and low costs. Looking at the electric powertrain, different and no standardized industrial proposals brought to analyse a specific laser application, the laser stripping and welding of enamelled copper pins. For the sake of improvement, the process is modelled and outputs qualification procedures are defined. Therefore, starting from an industrial case, an investigation about laser welding processing parameters and influencing factors is carried out following a new methodological path. The unnecessary presence of shielding gas and/or plume blower emerges, as well as the lack of influence of gap presence between two adjacent pins on the mechanical performance of the welds. Furthermore, a clear connection between upstream stripping quality and the consequent welding result is demonstrated and presented, allowing a sharp benchmark for the industrial production of hairpin windings.
L’attuale dinamismo nell'elettrificazione dei veicoli richiede cambiamenti radicali nella mobilità, nelle industrie automotive e in gran parte del settore dell'ingegneria meccanica. Tutti gli attori globali dell'industria automobilistica stanno compiendo grandi sforzi per sviluppare sistemi di propulsione elettrica efficienti in termini di costi, adatti alla produzione in serie. I processi di fabbricazione dei veicoli elettrici beneficiano di sistemi innovativi di produzione laser: sia in termini di efficienze di tempo, spazio e produttività, sia in termini di qualità, automazione e ripetibilità. Sebbene l'interesse del mondo scientifico in questo campo sia in continuo aumento, non esiste una visione approfondita e sistematica riguardante l'intera serie di applicazioni laser nel mondo della produzione di veicoli elettrici. In questa tesi, viene presentata un'analisi approfondita dell'attuale stato dell'arte scientifico e industriale su processi laser applicati nella produzione di veicoli elettrici, consentendo uno studio sistematico e metodico dei processi, dei loro punti di forza e di debolezza. L’indagine evidenzia un nuovo settore richiedente soluzioni tecnologiche alternative e diverse sfide: materiali difficili da lavorare come il rame, alta produttività, zero difetti e costi bassi. Con riferimento alla propulsione elettrica, diverse e non standardizzate proposte hanno portato ad analizzare una specifica applicazione laser, stripping e saldatura di fili di rame smaltato, a modellare il processo per migliorarlo e a definire procedure di qualifica dei risultati. Quindi, partendo da un caso industriale, è stato condotto uno studio dei parametri di processo e dei fattori influenzanti la saldatura laser, seguendo un nuovo percorso metodologico. Emerge l'inutile presenza di gas di protezione e/o di soffiante plume, nonché l’ininfluenza di eventuali spazi tra i pin sulle prestazioni meccaniche delle saldature. Inoltre, viene dimostrata e presentata una chiara connessione tra la qualità dello stripping a monte e il conseguente risultato di saldatura, consentendo un punto di riferimento preciso per la produzione industriale di hairpin windings.
Scientific and industrial survey of the laser-based applications in electric vehicle manufacturing with experimental focus on hairpin stator welding
Giudici, Angelo;GHIO, ALESSANDRO
2019/2020
Abstract
The on-going dynamism in the electrification of vehicles requires radical changes in mobility, automotive industries and significant part of the mechanical engineering sector. All global players in the automotive industry are making great efforts to develop cost-efficient electric drives, suitable for series production. The manufacturing processes of electric vehicles benefit from innovative laser production systems: both in terms of efficiencies in time, space and productivity and in terms of quality, automatability and repeatability. Although the interest of the scientific world in this field is continuously arising, there is no trace of a thorough and systematic analysis concerning the whole set of laser applications in the world of electric vehicles production. In this thesis is presented a deep analysis of the current scientific and industrial state of the art about laser-based manufacturing applied in electric vehicle production, allowing a systematic and methodical analysis of the processes, of their strengths and weaknesses. The survey highlights a new sector requiring innovative technological solutions, and some challenges: tricky-processing materials such as copper, high productivity, no defects and low costs. Looking at the electric powertrain, different and no standardized industrial proposals brought to analyse a specific laser application, the laser stripping and welding of enamelled copper pins. For the sake of improvement, the process is modelled and outputs qualification procedures are defined. Therefore, starting from an industrial case, an investigation about laser welding processing parameters and influencing factors is carried out following a new methodological path. The unnecessary presence of shielding gas and/or plume blower emerges, as well as the lack of influence of gap presence between two adjacent pins on the mechanical performance of the welds. Furthermore, a clear connection between upstream stripping quality and the consequent welding result is demonstrated and presented, allowing a sharp benchmark for the industrial production of hairpin windings.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/175093