Extremely Modular EV/ICE Platform: Nice Concept or Wishful Considering?

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The time period “modular” often has optimistic connotations. It might consult with one thing as fundamental as a chassis, which you plug numerous take a look at or I/O playing cards into. Or it may possibly even consult with one thing as sophisticated as a home that’s constructed utilizing particular person room designs inbuilt a manufacturing unit, that are then trucked to the constructing web site and assembled into an entire home. It’s additionally a phrase which frequently conceals—both deliberately or inadvertently—what’s concerned in a challenge.

The presumed advantages of modularity have been embraced through the years by automakers, amongst others, who use product-line “platforms” on which they construct totally different automobiles. In practically all these conditions, the modularity is generally on the physique stage and far much less within the energy prepare, utilizing a single or intently associated engine-transmission pairing, however with totally different physique kinds, interiors kinds and end.

However why cease there? I used to be intrigued once I noticed a narrative a couple of extremely publicized plan by Stellantis to make use of a extremely modular automotive platform for next-generation automobiles. Dubbed “STLA Giant,” this platform can accommodate many power-train choices. (Word: Stellantis is the guardian firm of Chrysler, Peugeot, Fiat and plenty of different well-known nameplates.)

The flexibleness covers propulsion—front-drive, rear-drive, all-wheel drive and multi-energy—that are supplied by a household of three scalable electrical drive modules. That’s lots of modularity and adaptability, I assumed.

This massive platform is one in every of 4 totally different sizes they’ve developed, primarily—however not completely—for battery-electric automobiles (BEVs). These 4 modular STLA platforms (Small, Medium, Giant and Body) are engineered to be future proof and are inherently versatile in wheelbase, width, overhang, trip top and suspension design, in keeping with Stellantis’ press launch. They’re additionally designed with provisions for future battery chemistries, together with nickel- and cobalt-free batteries, in addition to solid-state batteries.

STLA Giant is designed and engineered as a local BEV platform with the choice of 400 V and 800 V electrical architectures. It may be configured in front-wheel-drive, rear-wheel-drive and all-wheel-drive layouts utilizing transverse and longitudinal engine mounting configurations.

Along with BEVs, the STLA Giant platform additionally helps hybrid and inner combustion engine (ICE) propulsion programs, whereas the smaller ones are BEV solely.

The STLA Giant dimensional attributes are revealing, as indicated by their numbers (they usually accomplish that with too many important figures):

• General size vary: 187.6-201.8 inches (4.764-5.126 mm)
• General width vary: 74.7-79.9 inches (1.897-2.030 mm)
• Wheelbase vary: 113.0-121.1 inches (2.,870-3.075 mm)
• Floor clearance vary: 5.5-11.3 inches (140-288 mm)
• Most tire diameter: 32.6 inches (858 mm)

All this modularity and related flexibility looks like a really smart thought. However then I began fascinated about my very own previous encounters with modular design, each as a product designer and as a person. In lots of circumstances, the advantages and outcomes had been lower than anticipated, primarily for 2 causes:

• First, there’s the problem of design optimization. A modular platform requires compromise on options and efficiency to accommodate the assorted permutations and preparations inside a standard framework. Generally these compromises are minor or modest, however typically they don’t seem to be. So, as a substitute of a “excellent” non-modular design, you find yourself with a “sort-of good” modular one. The dimensions of the hole between excellent and sort-of good is difficult to know with out cautious evaluation.
• Second, there’s the idea that modular means you possibly can simply drop in “unit B” to exchange “unit A,” and accomplish that with minimal further adjustments to the platform, interconnections and supporting peripheral capabilities.

As soon as once more, expertise has proven that there are numerous different less-visible adjustments you should take to totally accommodate the drop-in different. The ripple impact of switching out even a single modest part can deliver nasty surprises. For instance:

• Weight and weight distribution will possible be totally different, so suspension will change.
• Completely different sensors are wanted for every sort of energy prepare.
• Cabling, wire gauges and connectors shall be very totally different.

I’m positive an in depth evaluation of the manufacturing invoice of supplies (BOM) and course of will reveal many different {hardware}, stock and production-process adjustments, along with the supposedly “painless” one in every of totally different software program packages.

There’s ample precedent for questioning and worrying concerning the total influence on design, manufacturing, take a look at, and in-use assist if you try and modularize and construct up in a logical method—admittedly from a distinct context. My perspective is from the guide “Apollo: The Race to the Moon” by Charles Murray and Catherine Bly Cox, the very best guide on the moon touchdown among the many many I’ve learn.

In a quick overview chapter, the authors level out that modular, stage-by-stage meeting of the rocket and capsule didn’t accomplish what folks thought it did. The guide notes that NASA challenge leaders realized this after a profitable first-stage take a look at, noting that “everytime you added a brand new stage, the bottom assist gear was totally different, the checkout procedures had been totally different, the {hardware} was totally different.”

The choice technique the Apollo challenge had to make use of for meeting and take a look at was non-intuitive and known as “all-up.” It meant that from the beginning, they’d assemble the rocket in its entirety solely in its closing configuration, utilizing subassemblies that had been individually examined, however not joined to others but. They might then take a look at the built-in rocket as a single accomplished system. This contrasts with constructing it up piece-by-piece and testing at every incremental construct step, which at first appears the extra logical method to do it.

I’m positive the engineers and others at Stellantis have studied this concept very rigorously earlier than implementing it. It can definitely be attention-grabbing to see how manufacturability, efficiency, assist and value points work out. I nonetheless surprise how a lot of the modularity story is predicated on precise financial savings and the way a lot is pushed by the conceptual attractiveness of the story (particularly to Wall Road) greater than the fact. We should wait and see about that.