The vehicle manufacturing of traditional manufacturers involves the body shop, paint shop, assembly shop, leakage testing before shipping, and multiple road tests. With today’s ever-changing technologies, almost all the manufacturing processes of international brands are automatic after delivering the steel coil for stamping. It’s only till the assembly shop will it require manual operation to finish some detailed works. In other words, the variable of assembly quality and time due to direct labor has lowered significantly in modern-day car production. Take one Japanese automaker, for instance, which has average production hours per vehicle lower than 23 hours, while similar models from US brands take about 25 hours. The difference in time mainly involves a few factors:
- An assembly-oriented car design.
- Reduced assembly time owing to optimal sub-assembly of component supplies before entering the production line.
- Shortened time with optimized software programming and operational efficiency of manufacturing equipment (especially for welding robotic arms and auto sprayers) while maintaining quality.
- Takt system implementations in the main and sub lines of the assembly line (including the door panel and powertrain system substations) ensure a bottleneck-free production process with ALB (assembly line balancing). The assembly line still has a heavy requirement for direct labor, which calls for balanced workstations to minimize the impact of assembly speeds by human factors.
When we exit the ICE age and enter the era of EVs, the above factors of car manufacturing efficiency have evolved:
- The assembly of batteries and motors is more intuitive and less labor-intensive than the ICE cars’ engines, gearboxes, fuel tanks, hoses, exhaust systems, etc.
- The trend of modular design drastically lowers the difficulty of component supplies and the assembly process when transitioning between different models in mixed-model productions (assembling several distinct models on the same assembly line without changeovers).
- Aside from its innovation in product technologies, Tesla’s revolution in the manufacturing process (for example, the Cell-to-Chassis 4680-type battery cell and integrated underbody design not only simplifies the battery manufacturing process but also aids in the assembly process by employing massive die castings to create unified aluminum-alloy chassis) fully utilizes the two former factors. According to Tesla, a single vehicle’s production time can fit under 10 hours, far lower than the time for BEV from other traditional carmakers.
- However, the short supply of key components like batteries and chips has already proven to be the biggest non-technical issue. Some production lines even roll unchipped vehicles offline, which increases the labor arrangement’s complexity for retrofitting works and the pressure on storage spaces. And, of course, if there’s battery shortage issue happened, then a shutdown is inevitable.
Minus the non-technical aspects of the key components’ supply chain, EVs already boast a vastly reduced number of components. Moreover, their battery pack’s “shape” is flexible according to the assembly spaces, unlike ICE cars’ powertrain system, fuel tank, and exhaust system’s rigid layout, resulting in little space to simplify the shape of the underbody and the welded bracket’s (for fixing chassis parts) design. The design approach of simplifying EV underbodies is, for sure, a revolutionary technology to increase the efficiency of EV production. Although in the end, who would’ve thought this technological advance would come from an EV startup, Tesla?