Manufacturing and Assembly of the Electric Powertrain: Quickly and Reliably Developing In-house Production

The burgeoning market for electric vehicles (EVs) presents great opportunities — and challenges — for vehicle manufacturers. Confidence about the long-term market potential has taken hold, but the trajectory of growth remains uncertain. In addition, EV technology is rapidly evolving, as are manufacturing processes, making OEMs cautious about committing significant capital investments to production capabilities.

However, manufacturers are beginning to ramp up electromobility production capacity to establish a foothold in the market, gain experience, and position themselves for success in a future when the internal combustion engine may eventually become as rare as a buggy whip.

Outsourcing Electric Powertrain Components to Tier I Suppliers

Vehicle manufacturers have often relied upon Tier I suppliers for the powertrains of early EVs as a relatively easy, quick, and low risk way to enter the market. OEMs can readily purchase off-the-shelf components, thereby leveraging the design, development, and testing that the Tier I suppliers have refined from past experience. And there is often no need to make a long-term commitment to particular product technologies or production volumes.

The Tier I suppliers have essentially served as a buffer between the known and the unknown, giving vehicle manufacturers time to develop expertise while allowing the market to mature and stabilize. They also offer a strategic alternative to in-house production for low volume niche applications and specialty motors.

Inhouse Manufacturing and Assembly of the Electric Powertrain

More recently, as the EV market has begun to settle, OEMs are more often building their own internal manufacturing and assembly capabilities for both motors and batteries. This trend reflects higher confidence in the maturity of the technology and in the volume and predictability of future demand. In-house production can be much more economical in many instances and gives the OEM more control over quality and production capability and throughput.

But electric powertrains are a very different domain than the world of internal combustion engines, and OEMs typically recognize the limitations of their own expertise in this relatively new and rapidly evolving area. The company culture and organizational practices of some vehicle manufacturers are being further stretched by the accelerated pace of industry change.

OEMs are very knowledgeable about combustion engine powertrains: the process pitfalls, the labor and floorspace requirements, and the capital price points. But for many of them, this is their first venture into electrification, and they need guidance and feedback in setting strategies, expectations, and even budgets, and in aligning cycle plans to manufacturing strategies that match spending objectives.

Similar to how they have worked with Tier I suppliers, OEMs are relying on suppliers of manufacturing lines and assembly systems specializing in E-Mobility to augment their own expertise.

In our case, at GROB, many of our OEM customers that have extensively utilized our manufacturing systems for internal combustion engines are now partnering with us to build on that relationship and take advantage of our broad and deep E-Mobility capabilities.

Single-Sourced Assembly Systems

Our customers are also tending to choose a single source supplier for the entire manufacturing and assembly process, for several reasons.

In general, working with a single source affords strategic benefits in any production process, especially for products with rapidly evolving and highly complex technologies and manufacturing processes like E-Mobility components.

Each step of the assembly process is highly dependent on the prior process step. When different suppliers are “handing off” to other suppliers, it is a proven fallacy to assume that the process will be contiguous and successful. And when multiple suppliers are involved, it can be difficult to quickly and accurately diagnose the cause of failures, assign responsibility and implement corrective actions.

For example, the welding of the hairpins is highly influenced by the enamel stripping and trimming processes upstream. Subtle variations on either process can have a big influence on welding. And if the supplier of those processes does not conform to those parameters, the welding process will fail. This same problem applies to nearly any process step, if the sourcing of processes is split between separate companies.

Complexity of Stator Production

Hairpin stator technology is still a relatively recent innovation in traction motors. Hairpin stators have significant functional advantages compared with other stator technologies — high power density, efficiency and thermal performance. Unfortunately, they can be extremely complex to manufacture and serve as a good example of the need to coordinate and integrate the various operations in the production line with a single supplier.

As the OEMs and Tier I suppliers become more confident with hairpin stators, they are introducing more complexity in the designs, and this presents additional challenges to manufacturing. Early hairpin stators, for example, routinely included four or six hairpins per slot. Today, eight or ten hairpins per slot is quite common. Dimensional requirements, busbar designs, and resin insulation are also becoming more demanding for production.

Complete Solution

Ideally a single-source solution will involve more than just supplying the manufacturing equipment; it will be a complete solution, where the supplier of the manufacturing and assembly systems actively participates. The supplier should significantly contribute to not only the processes themselves, but the product design, the A, B, and C-sample prototypes, and the long-term success of the production system.

This collaboration begins during the product design phases, as it relates to function and manufacturability. The supplier brings expertise on leading-edge designs and processes and a critical eye based upon lessons learned elsewhere. Many customers have depended on GROB’s experienced in-house motor design team to improve their stator function and its manufacturability, leading to reduced capital expenditures and lower overall life-cycle costs.

Prototyping and testing are also critically important, early and often, throughout the entire development process. Building prototypes shakes out defects early and exposes ideas in order to improve process concepts. For example, at GROB, we helped identify enamel deficiencies in a customer-supplied wires that would have been catastrophic if released for production, and we worked with a customer to completely eliminate a troublesome epoxy coating process by producing and testing design variations.

A Successful Strategy

To be successful in the dynamic E-mobility industry requires an experienced and trusted partner. GROB’s knowledgeable 6800 employees worldwide offer proven solutions for all components of the electric powertrain. Leading OEMs and Tier I suppliers have depended on GROB’s innovative spirit, long and successful resume of past installations, and our approach as a true partner to lead them into the new arena of electrification.

Author: Glenn Oshel, Key Account Director, e-Mobility, Grob Systems, Inc.