# Tag Archives: EV penetration rate

## Testing Tony Seba’s EV Predictions 16 (Range Anxiety and the Need to Wee)

When Jack Rickard pulled the battery out of a wrecked extended range Model 3 in a previous post, it weighed in at 478 kg. We are talking here of a 75 kilowatt-hour (kWh) battery. If you have a high tolerance for ‘slow video’ then you can see Jack, together with Bill from Ace Hardware, Linden, Tennessee, extract the battery from a Model 3 (I rather like Jack’s vlogging style, but then perhaps I should get out more).

Let us put this battery into some kind of context. If we divide the energy storage of the 75 kWh Tesla battery Jack Rickard extracted by its weight of 478 kg we get 0.157 kWh per 1 kg of weight. Let’s change our unit from kilowatts to watts: so we get 157 watt hours (Wh) per kg. Note we are talking about the entire battery here, not the battery cells.

The measure of the amount of energy per unit of weight is referred to as the specific energy or gravimetric energy density. If you are building EVs you want to have as high as possible specific energy for your battery. Each technological advance then allows you to either store the same amount of energy for less weight, or store more energy for the same amount of weight.

When you compare EVs with internal combustion engines (ICEs), the EV basically wins hands down with respect to the delivery of power. So boosting the specific energy of the battery is about having more energy in your battery (rather than power). This, in turn, gives your car more mileage range. Indeed, a critical goal in battery development is to boost specific energy to such an extent that mileage range becomes a non-issue. Nonetheless, even if your battery can deliver all the possible miles that an owner could wish to drive in one sitting, an incentive still exists to boost specific energy even further because that would allow you to continually shrink the battery.

Keep in mind that the Model 3 Tesla battery Jack extracted weighs 28% of the overall vehicle weight. So let’s do a thought experiment and imagine that Tesla doubles the specific energy of the battery to 300 watt hours per kg (wh/kg).

The current Tesla Model 3 has a range of 310 miles according to the US government’s Environment Protection Agency (EPA); pretty good, but I should think the consumer is greedy for more. Let’s decide to increase the mileage range by 50% to around 450 miles between charges. With our new 100% specific energy improved battery we could deliver 450 miles plus shrink the battery by 25% to about 325 kg. We are, in effect, lightening the car by over 100 kg. And, if we are lightening the car by 100 kg, we are making it more efficient.

The extended-range Model 3 weighs in at 1,730 kg; if we drop 100 kg in weight, that translates into a weight saving of around 6%. And given a chunk of the battery’s energy is used up lugging the battery itself around, every time we shrink the battery we release energy that can be used for moving the rest of the vehicle and its occupants. This, in turn, allows us to shrink the battery further. In other words, we have a nice little positive feedback loop emerging here.

Specific energy is not energy density. The term energy density, or volumetric energy density, refers to the energy stored per unit of volume, or watts per litre (wh/l). In an ideal world, I would have loved it if Jack had also taken the dimensions of the extracted Tesla battery as well. Then we could have worked out a real-time energy density number for the Model 3 battery. In the chart below, however, you can see that a linear relationship exists between specific energy (termed here gravimetric energy density) and volumetric energy density. Therefore, as we achieve specific energy enhancements, we generally get energy density improvements as well.

Put another way, as you lighten the battery you will also reduce its size. And every time you do that, the size of the total drivetrain, including energy source, gets more competitive versus the ICE drivetrain plus fuel tank. Note that the EV has already won in the configuration competition with an ICE vehicle. You have far more latitude in arranging your drivetrain components with an EV since you are just connecting them up with wires. No crankshaft or gear box required.

Let’s talk a bit more about range. We’ve established that the extended range Tesla Model 3 can drive around 310 miles on a fully charged battery according to US government statistics. So we get 3.85 miles per kWh. Speed limits in the USA vary by state, but the highest speed limit is found in states like Texas and comes in at 75 mph. So our 310 mile range for the Tesla translates into roughly 4 hours 10 minutes of driving time in the high-speed-limit states, and that is assuming the entire journey is at the maximum speed limit.

Given the average motorist doesn’t wear adult diapers while driving, he or she will periodically need to get out of the car to urinate or defecate. Moreover, I propose that the need for a wee is the limiting factor here, so the act of urination is our boundary constraint (apologies to irritable bowel sufferers). According to WebMD, the average adult urinates between once every two to four hours. So I will take an ‘iron bladder’ as my example Tesla driver. Bottom line, the car will not run out of energy before the girl or boy has gotta go.

Nonetheless, we have to think about how long it takes to charge the car up again. And then we need to plug that number into an equation that also incorporates the time it takes to exit the car, hook it up to a recharging source, walk over to the toilet facility, urinate, walk back to the car, unhook the car from the charger and then drive off.

So does time to wee equate to time to charge? Curiously (at least for me), the “Law of Urination” states that mammals in general take 21 seconds to pee. So the actual act of urination is not the limiting factor here, rather accessing a place to urinate is the issue. For argument’s sake, I will assume that the toilet break is limited to 20 minutes since we need to walk to and from a toilet cubicle.

Next we need to know how long it takes to charge the Tesla. There are a lot of factors that come into play here including the starting charge of the battery, the desired ending charge of the battery and the quality of the charger. Given we are interested in the dynamics of a long road trip here, the driver is going to be using some kind of supercharger network. To get a sense of the charging experience at a Tesla Supercharger, check out the video here:

In the video, you can see a top charging rate of 100 kW, which translates into 375 miles added per hour. The theoretical top charging rate at a Tesla Supercharger is actually 115 kW, but as the battery gets close to being fully charged, the rate of charging drops off.

What can we deduce from all this? Well, if a long distance driver wants to do two back-to-back journeys of around 300 miles each at the top speed limit allowed in the USA and only needs one toilet break of 20 minutes, then the Model 3 can’t deliver that kind of range performance (but an ICE vehicle can). You currently need a good hour of charging in that scenario for your Model 3, even assuming access to the best possible charging rate at a Supercharger.

At this stage, you may point out that the vast majority of car journeys don’t include driving 600 miles straight in two back-to-back sessions with a 20 minute break in between. But that is not really the point. In an earlier post, I established the conditions needed for the auto market to tip between being ICE dominated and EV dominated. The condition was that an EV needed to match or exceed an ICE vehicle in every car attribute. So if an ICE vehicle is superior for long distance marathon driving, EV penetration will be slower.

Nonetheless, it is only the year 2018, and Tony Seba’s 95% EV penetration-rate target by 2030 is still 12 years away. Further, I think the EV is not that far away from matching an ICE for long-distance driving already for two reasons.

First, as the battery capacity gets bigger, the battery will still have a lot of juice when the driver reaches the first toilet stop. With a 50% bigger battery and a 450 mile initial range (achieved through charging overnight), 150 miles will be left in the battery at the first stop. So for leg number two of the journey, only half the charge time is required since we are only topping it up and not starting from zero. (Yes, we could talk about three back-to-back stages amounting to 900 miles, but the driver will eventually have to eat, and, as we get beyond the 99.9% percentile of typical journeys taken, I think we can view these as true outliers.)

Second, as each Supercharger generation is rolled out, the rate of charging will go up. Tesla has already flagged that the V3 Supercharger will arrive this summer and the rate of charge is likely to be between 200 kW and 250 kW, so a roadmap exists toward halving the best current charging time.

Beyond Tesla, two open standards exist that allow shared usage by vehicles produced by different auto makers. These are the CCS standard (backed by the CharIn consortium) and the CHAdeMO standard. CCS, promoted by the German auto makers amongst others, is working toward a charging rate of 350 kW as well as inductive wireless charging stations. The CHAdeMO consortium, which is principally composed of Japanese automakers and electric power companies, is aiming for a rate of 400 kW in the coming years. A good primer on fast-charging protocols can be founder here.

Both CCS and CHAdeMO are having to play catch-up with Tesla’s Supercharger network, which has just reached 10,000 sites worldwide. Undoubtedly, Tesla’s strategy of “build them and they will come” appears to be far superior to the opposition’s strategy of “we will build them when they ask for them”. You can check out Tesla’s global Supercharger network here.

Summing up, while I think access to fast charging facilities will become a non-issue in a few years time, the need for batteries to get better with respect to specific energy and density is still a pressing need if EVs are going to unseat the current dominance of ICE vehicles. Further, to get the required improvement, do we need a John Goodenough-style leap in battery technology or will a Tesla-style incremental improvement in existing technology suffice? That will be the subject of my next post.

For those of you coming to this series of posts midway, here is a link to the beginning of the series.

## Testing Tony Seba’s EV Predictions 14 (Deconstructing the Car)

In my last post, I set the conditions that determine whether the auto market tips from internal combustion engine (ICE) vehicles to electric vehicles (EVs). EVs need to either match or exceed ICE vehicles with respect to every car ‘attribute’ at an equivalent cost. Then it’s game over for ICE vehicles.

The attributes of a car give a consumer happiness. That utility comes from a) the mobility a car provides, b) the aesthetic of the car (the pleasure the owner gets in owning the car that is not related to other people) and c) status-signally through displaying ownership of the car to other people (such status signalling is not restricted to investment bankers and their Ferraris; it also covers hippies in their Citroen 2CVs and Green Party members in their Nissan Leafs).

The purchase decisions of consumers are based on their current budgets and future budgets. Current budgets determines how much they are able to pay for cars and future budgets determine how much they can afford to run their cars (fuel, maintenance, depreciation).

If EVs are better with respect to some of these aspects of the purchase decision but worse in others, then taking market share from ICE vehicles will be an uphill slog. That is what Exxon Mobile believes as illustrated in this chart from its latest “Outlook for Energy: 2018”:

If such a projection is correct, around 50 million EVs will be on the road (which includes pure battery and plug-in hybrids) in 2030. That compares with the Tony Seba S curve view of 130 million EV sales alone in that year.

To tease out who is likely to be right, let us think of the physical limits auto makers have to work with. Basically, a car is a three dimensional irregular cuboid shape constrained by such external factors as lane width and parking space size. Certain things are then put into this irregular cuboid shape to provide the mobility, aesthetic and status-signalling attributes we identified before.

Lots of car ‘stuff’ is not a function of whether it is an ICE vehicle or EV. For example, the headlights, wing mirrors, windscreen wipers and so on. We can exclude such items from our analysis since an EV can match the ICE vehicle in these domains. Moreover, there is no reason why an EV can’t match an ICE in terms of aesthetic or status-signalling should its design be good enough and its ability to fulfil the mobility criteria.

The main differentiator between an EV and ICE vehicle when it comes to mobility relates to the drivetrain. Taken, holistically, we can think of this as encompassing a store of energy and a means of converting that energy into motion. We can now compare EVs against ICE vehicles in respect of this broadly defined drivetrain across a series of factors, most importantly:

• Weight
• Volume
• Efficiency
• Flexibility

Given its position as the undoubted pacesetter in cutting edge EV design, performance and production numbers, Tesla’s Model 3 is a worthy champion for the EV camp. The standard Model 3 has a curb weight of 1,610 kg, while the extended range version is 1,730 kg. The crotchety Jack Rickard did a tear down of a wrecked extended-range Tesla Model 3 (warning: it is a long video) and extracted the battery, which weighed 478 kg. So that means the battery weighs roughly 28% of the car.

Let’s choose the BMW 330i Sedan as a typical ICE competitor for Tesla; its specifications taken from BMW’s USA site can be found here. This sedan comes in at 1,610 kg, so the Tesla is 7.5% heavier. Curb weight generally includes a full tank of fuel, which in the BMW’s case is 15.8 gallons or about 45 kg in weight (you can see here the extraordinary energy density of fossil fuels).

So that in a nutshell is the handicap of the battery as an energy source: more than 400 kg of extra weight. On the other side of the ledger is the fact that you wonder where the engine has gone in an EV. Here is the schematic for the Model 3:

First, you notice the radical shrinkage of the actual engine itself. An internal combustion engine is a system of controlled explosions that first translate into lateral movement of the pistons, which in turn has to be translated into circular movement to the wheels. That requires a complex multipart machine.

The video below compares and contrasts the Tesla drivetrain with a traditional ICE (but note it highlights the induction motor in the Model S; the Model 3 motor and electrical motors in other automakers EVs are somewhat different) and emphasises the fact that the electrical engine has radically fewer parts.

And here is a couple of minutes on the Model S engine showing its intrinsic simplicity:

The key differentiator, obviously, is the disappearance of a bunch of ICE components: transmission, exhaust system, fuel pump, fuel injection and spark plugs. An EV does need some kind of cooling system for both the motor and the battery, but this is relatively modest in both weight and volume.

Overall, if we take out the gas tank and the battery from the equation then we get this:

EV drivetrain weight <  ICE drivetrain weight

EV drivetrain volume < ICE drivetrain volume

But through adding the battery and gas tank back in, these inequalities reverse:

EV drivetrain weight >  ICE drivetrain weight

EV drivetrain volume > ICE drivetrain volume

Now, it’s very difficult to put numbers into these inequalities. But the interesting thing about Tesla’s Model 3 is that it incorporates a large battery in terms of kilowatt hours (kWh) but the car is still in the same ball park weight category as its ICE competitors. Moreover, we are currently going through a period of rapid battery cell shrinkage (weight and volume per kWh). Let’s say Tesla can shrink the 479kg battery that Jack Rickard extracted from the wrecked Model 3 by 25%; that would give a weight saving of 120kg. We are now getting into matching territory. And remember the conditions for tipping. EVs don’t need to exceed ICE vehicles for the market to tip: they just need to match in most areas and excel in a few.

Next we come to flexibility, which really relates to the configuration in our irregular cuboid. So yet again putting the battery to one side, the EV has an instant advantage. The drivetrain units can be arranged more flexibly as they are linked principally by wires, not by a complex transmission mechanism.

Even with the battery, the possibilities of dividing it up and distributing it around the car have yet to be explored. Safety and cooling issues not withstanding, the overall battery is cellular and is just composed of thousands of small batteries. We talk of form factors with mobile phones, and this is ultimately where we will move with cars. With an ICE, you have to design around the drivetrain, with an EV the drivetrain can become subservient to the design.

So then we move to efficiency, with respect to which the EV wins hands down. An electrical motor can deliver instant power and torque. In the US context with imperial units we have this equation.

Which translates into this chart:

As a result of the dynamic in the above chart, Tesla is currently able to deliver supercar type performance at a fraction of the cost of the likes of Porsche, Bugatti or Ferrari (source: here). Note that Tesla’s new Roadster due to be released in 2020 will have a base model that delivers zero to 60 in 1.9 seconds; that will be the first production car ever to break two seconds.

Moreover, such high-end, halo EV performance profiles will trickle down. Ultimately, taking price to price comparisons, the EV will leave the ICE car in the dust when the stop light turns green. For those of a non-macho disposition, you may not care. But to repeat (again) if the EV is equal on all metrics but ahead on just one that you care about (all at an equivalent price), then you will buy the EV.

And yes we still have the constraint of range and price. And yet again this takes us back to the battery. Indeed, the EV battery is like the little Dutch boy Hans Brinker whose finger in the dyke is the only thing stopping the entire neighbourhood being flooded and his family and friends being drowned. But once the battery gets down to a price and efficiency point not far from now, that dike will go and the ICE industry with it. The battery is the subject of my next post.

For those of you coming to this series of posts midway, here is a link to the beginning of the series.