A great illustration of what's wrong with EVs built on gas platforms

KarenRei

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#1
Above: Chevrolet Bolt
Bottom: Hyundai Kona EV


(Image from user Cypress at Electrek)

Both vehicles are almost identical in size. But notice how much less room for passengers and cargo the Kona has, due to the hard-to-utilize space in the "engine compartment". That engine compartment effectively pushes back the driver's seat, which has a knock-on effect on everything behind it. The net result is that Kona is very small inside.

Also, while they tried to compensate for drag (note, for example, the aero wheels, which Bolt doesn't have; they also have some limited horizontal rear taper), Kona's aero is compromised compared to the Model 3. Despite Kona being a smaller vehicle, Model 3's EPA highway efficiency is 11% higher. Their city efficiencies are almost identical - despite Model 3 having much more interior space - because their weights are almost identical, despite Model 3 LR having a somewhat higher capacity pack.

Structurally, the front end is designed to crush on the assumption of having a relatively incompressible engine inside it, so it can't take proper advantage of all of that extra space.

On the underside, the Kona's pack juts out awkwardly from the vehicle (because they had nowhere else to put it) and just looks like it wants to catch on something. In practice, it's probably not as bad as it looks - they've lifted vehicle relatively high off the ground for a "city car", and the measured clearance is reasonable. But it certainly looks exposed. The frame just wasn't designed for a battery pack.

Let's all say it together: "EVs should be built on platforms that were intended from the beginning to be for EVs."
 
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Quicksilver

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From my perspective, the frunk works by harmonizing two functions - useful storage and crumple zone for safety. Just a brilliant way to address both vehicle aesthetics and pragmatism.
 

garsh

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From my perspective, the frunk works by harmonizing two functions - useful storage and crumple zone for safety. Just a brilliant way to address both vehicle aesthetics and pragmatism.
It is. But why don't the car manufacturers that are creating these dual-use platforms use it that way?

Instead, they just waste all that space by throwing all of the control electronics up there, in the middle of the engine bay. Sure, it's easier to manufacture on the same line as the ICE version - the installer has a "stack" very similar to the engine "stack". But it's such a wasted opportunity for incredible storage.

I mean, look at the Kona EV's "engine bay". They could have made things more compact, and shoved all of that stuff around the edges, and had some decent storage up front.

 

KarenRei

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#6
It is. But why don't the car manufacturers that are creating these dual-use platforms use it that way?

Instead, they just waste all that space by throwing all of the control electronics up there, in the middle of the engine bay. Sure, it's easier to manufacture on the same line as the ICE version - the installer has a "stack" very similar to the engine "stack". But it's such a wasted opportunity for incredible storage.

I mean, look at the Kona EV's "engine bay". They could have made things more compact, and shoved all of that stuff around the edges, and had some decent storage up front.

One thing Tesla seems to be focusing heavily on, and which I think is very important, is clustered "assemblies" of logically-associated parts. You put tiny bits together to make little bits. You put little bits together to make medium-sized bits. You put medium sized bits together to make large bits, and you put those together into making even larger bits. Everything logical gets clustered together into a single assembly which has its rigid attachments that are easy for robots to deal with and a minimized-number of fiddly bits (cables, hoses, flexible parts, etc) that need to be connected by humans (Tesla has learned the hard day to fear the fiddly bits, as robots don't play nicely with them ;) )

The motor, gearbox, and inverter are all one compact assembly. The batteries, BMS, charger, etc are all one assembly. You look at the Ingineerix teardown and you see signs of this clustering all over the place. Each time they cluster things together, they can group together the whole assembly's inputs and outputs together, leaving fewer things to connect individually - including potentially fewer "fiddly bits". Given their painfully-earned experience with automation, I expect to see even more clustering with the Y, trying to make it to the point to where final GA goes together as a minimal number of large, pre-finished assemblies with a minimal number of external connections.
 

Quicksilver

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#7
It is. But why don't the car manufacturers that are creating these dual-use platforms use it that way?

Instead, they just waste all that space by throwing all of the control electronics up there, in the middle of the engine bay. Sure, it's easier to manufacture on the same line as the ICE version - the installer has a "stack" very similar to the engine "stack". But it's such a wasted opportunity for incredible storage.

I mean, look at the Kona EV's "engine bay". They could have made things more compact, and shoved all of that stuff around the edges, and had some decent storage up front.

I know, it’s crazy that they still use legacy mentality in designing new electrified vehicles. When I first saw the “engine” bay under the hood of the Bolt, I was shock to see they have not learned and moved away from the past. Maybe not too shocking, given they are a legacy manufacturer. They did use a skateboard battery pack design though.
 

Jayc

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#8
>> What's wrong with EVs built on gas platforms ?

Nothing wrong per-se but the advantages (and limitations) in designing for EVs differ with those for ICE.

What is wrong is not taking that opportunity to design from ground up, purely driven by design requirements for EVs in order to maximise the advantages and minimise on the limitations.

It is as simple as that.
 

JWardell

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#9
I mean, look at the Kona EV's "engine bay". They could have made things more compact, and shoved all of that stuff around the edges, and had some decent storage up front.

:eek: Why on earth would they have high voltage lines going toward the front bumper?!? :eek:
Even a small accident will have major chances of high voltage short, and repairs will be astronomical with all the expensive electronics in the crush zone!

Yet another unseen benefit of Tesla's engineering: no major/expensive/high voltage components within the first few feet crush zones in front AND rear!
 

SwaggerWagon

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#12
Above: Chevrolet Bolt
Bottom: Hyundai Kona EV


(Image from user Cypress at Electrek)

Both vehicles are almost identical in size. But notice how much less room for passengers and cargo the Kona has, due to the hard-to-utilize space in the "engine compartment". That engine compartment effectively pushes back the driver's seat, which has a knock-on effect on everything behind it. The net result is that Kona is very small inside.

Also, while they tried to compensate for drag (note, for example, the aero wheels, which Bolt doesn't have; they also have some limited horizontal rear taper), Kona's aero is compromised compared to the Model 3. Despite Kona being a smaller vehicle, Model 3's EPA highway efficiency is 11% higher. Their city efficiencies are almost identical - despite Model 3 having much more interior space - because their weights are almost identical, despite Model 3 LR having a somewhat higher capacity pack.

Structurally, the front end is designed to crush on the assumption of having a relatively incompressible engine inside it, so it can't take proper advantage of all of that extra space.

On the underside, the Kona's pack juts out awkwardly from the vehicle (because they had nowhere else to put it) and just looks like it wants to catch on something. In practice, it's probably not as bad as it looks - they've lifted vehicle relatively high off the ground for a "city car", and the measured clearance is reasonable. But it certainly looks exposed. The frame just wasn't designed for a battery pack.

Let's all say it together: "EVs should be built on platforms that were intended from the beginning to be for EVs."
The thoughtful layout of the 3 is one of the things that still blows me away after 4,400 miles of driving it. I can get all my tools in the trunk, plus my parts bin and overnight bag. In my Forester, I had to have the bag and bin in my back seat - no room left in the trunk once the tools were in. AND the 3 still has the frunk, and a lot of storage in the center console. The layout is simply amazing.
 

Spiffywerks

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#13
I recently watched these videos and they were incredibly informative as to why Tesla is so far ahead of the pack in consideration of their battery design and choices. The battery pack is amazing and something other Car mfg making EVs have a long way to go to catch up.