This is part two of “A Tesla Back of the Envelope.” The point of BOTE is to boil down complex issues by applying simple math along with basic facts to provide insight. In some cases, the oversimplification method works easily, but in this case it fails. The first post discussed the commonly held theory that EVs, like the ones produced by Tesla, are more reliable and simpler to manufacture because they have fewer parts.
To test this theory, we will consider similarities and differences between Internal Combustion Engine based vehicles (ICEs) and Electric Vehicles (EVs). ICEs and EVs have air bags (and other safety gear), comfortable seats/floors, about the same number of windows/doors/trunks, and common wheels/hubs/tires. ICE vehicles have very high part counts for engines, air handling, oil handling, and heating/cooling. EV assembly includes electronics boards, electric motors, and gadgets. Upon examination the number of parts for an EV is much higher than anticipated.
Circuit boards for example have hundreds or thousands of individual parts inserted and soldered onto the board during highly automated production. These boards are a single sub-assembly parts assembled by highly automated robotic production with assembly processes designed to put the maximum number of parts in the smallest space. During repairs a single circuit board is often discarded, with hundreds or thousands of parts trashed at the same time alongside the failed chip. In ICE vehicles the maintenance consumes wholesale parts with fewer for a fix (like brake shoes instead of regenerative braking on an EV). The parts for EVs are packaged in discrete units that are fully assembled by automation. ICE assembly still uses parts that require manual assembly.
Many EVs are still newer to the market and data on ‘wear and tear’ and servicing requiring parts aren’t as obvious as it will be in a few years. Part of the assumption “in people’s heads” is the assumption that mechanical applications will be more complicated. This is not true when considering the “gull wing doors” on some Tesla models! A BOTE that is useful in very high-level thinks – and may not be useful at detailed levels when a lot of data (like future repairs costs) are not yet known.
You can read part 1 of the blog post at https://www.ekalore.com/post/a-tesla-back-of-the-envelope
If you’d like to read more Back of the Envelope posts you can find them at www.ekalore.com/bote
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