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Do androids dream of electric cars?

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Alexander Howard
1312805.  Thu Feb 07, 2019 12:26 pm Reply with quote

I think what the writer is saying is that big new stations are a problem for all the reasons you say- they take forever to get approved and the only recently agreed one was where the government pledged an eye-watering subsidy - but small, modular stations would only need local planning permission and could be emplaced locally.

We could a bunch of them under our nearby big town. Except that it is in the constituency of the relevant minister, and an almost-marginal seat at that. If they are put in safe Labour seats, they would provide jobs and not affect the electoral arithmetic however popular or unpopular they are. Cynical? Nah.

 
cnb
1312809.  Thu Feb 07, 2019 1:01 pm Reply with quote

suze wrote:
PDR wrote:
Alexander Howard wrote:
Or at were called petrol stations you hoick out the discharged cells from your battery and swap them for ready-charged and refurbished cells.


This might be do-able ... (But) personally if I'd just bought a car with a 20,000 battery I ain't going to swap it for some tired old piece of junk at some random roadside garage.


Alexander's idea was tried in Israel, and the company behind it went bust in fairly short order. That is said to have been down to bad management as much as a bad concept, but the objection which PDR raises absolutely was part of the issue.


It's a concept that has been discussed for a long time, and I'm not aware of any planned scheme that had the downside proposed by PDR. All the schemes proposed assumed that the vehicle was bought without a battery, and that the battery was leased on some combination of time, mileage and usage. The leasing company (such as Better Place) would own all the batteries, and be responsible for replacing faulty ones. It's very similar to the bottled propane business model, where the gas company owns the cylinders and swaps empty ones for full ones. You don't worry about the condition of the replacement gas cylinder you get from a roadside garage, so why would you worry about a battery?

The real problem with this business model is that long journeys where charging time really matters to people are rare, especially in small densely-populated countries like Israel and Denmark and Hawai'i (where Better Place operated). People don't want to be paying the costs of a complex battery swapping infrastructure all the time, when most of the time they're making short journeys.

In the UK only about 5% of 'vehicle use days' involve journeys over 200 miles - the other 95% of days you recharge at home overnight, or spend half an hour a week at a public fast charger.

suze wrote:

In other words, and as I suggested yesterday, no one wants a nuclear power station in her back yard. There will be "significant local opposition" to any and every proposal to build one in a populated area. The article does not consider how that can be overcome, perhaps because it can't be.


In part that depends how many of the objections are because it's a nuclear power station, and how many are because it's a big ugly power station. A power station based on a submarine reactor would be the size of a large house, with a garden full of cooling equipment. It would be effectively invisible in a medium-sized industrial estate.

There would also be a need for a very large number of them - a few hundred - so they would be in every town of any size. It's easier to convince someone that something is not terrible for them when they don't feel they're being singled out. It's not going to be in your back yard, it's going to be in everyone's back yard.

 
tetsabb
1312814.  Thu Feb 07, 2019 1:44 pm Reply with quote

One Nissan Leaf, two or more Nissan Leaves, Shirley?

 
suze
1312818.  Thu Feb 07, 2019 1:49 pm Reply with quote

But somewhere perforce has to be first. That somewhere won't be a safe Conservative constituency, because the MP will say "I think not" and the PM will say "Jolly good, someone else's backyard first then".

If that somewhere belongs to a Conservative MP with a small majority, she'll campaign against it because the blue rinse brigade have told her that they will vote yellow or purple if she doesn't. If it belongs to a Labour MP, she'll campaign against it because anything the government is for, she is against.

The public inquiry will last three years because that MP and her friends in the CPRE will make sure of it, and then the "Swampy Contingent" will turn up. We had them here in Rochester when E.ON wanted to do nothing more than to rebuild an existing coal-fired power station, and they were part of the reason that E.ON eventually said "Do you know what, sod this". Opposition to the plan included all the usual suspects - the Swampies, Greenpeace, Dr Caroline Lucas, the CPRE - but also the Church of England, and, would you credit it, NASA!

That scenario wouldn't have to be replayed in very many different towns before the people who were planning to build the power stations gave up on the idea.


tetsabb wrote:
One Nissan Leaf, two or more Nissan Leaves, Shirley?


Plural Canadian emblems are usually Maple Leafs. No one really knows why, but it has been so since about 1895.

 
cnb
1312837.  Thu Feb 07, 2019 5:32 pm Reply with quote

suze wrote:
But somewhere perforce has to be first. That somewhere won't be a safe Conservative constituency, because the MP will say "I think not" and the PM will say "Jolly good, someone else's backyard first then".


For such a project to get underway the manufacturer would need the certainty that they would have the economy of scale of hundreds of units. To get that they'd need to get permission for the first, say, 50 before they started any on-site work.

I'm not a planning expert, but I'd have thought that if you applied for permission for 50 identical plants on 50 industrial estates all across the country, the result would be a single public enquiry which would look into the general question of whether a nuclear power station in a suburban industrial estate is acceptable in safety terms. That might take 5-10 years, but if the result is that it is acceptable, then all 50 will get approved as beyond that it's unlikely that there would be any valid objections to planning permission. With 30 or so sites being built simultaneously, there would be no focus for any on-site protest.

 
suze
1312841.  Thu Feb 07, 2019 6:33 pm Reply with quote

cnb wrote:
That might take 5-10 years, but if the result is that it is acceptable, then all 50 will get approved as beyond that it's unlikely that there would be any valid objections to planning permission. With 30 or so sites being built simultaneously, there would be no focus for any on-site protest.


I'm no planning expert either, but let us suppose that a longwinded public enquiry did indeed validate the concept.

The fifty power stations would then still need planning permission, and in each relevant local authority the Plannng Officer would cite the public enquiry in recommending that it be granted. However, the councillors are not bound to vote in accordance with that recommendation. It is no way illegal for them to vote politically rather than sensibly, or in line with their emails from constituents rather than sensibly, and it is not rare.

There are any number of instances, but a notorious one concerned Mole Valley District Council in Surrey in 2007. An Armed Forces charity bought a long-empty seven bed house in Ashtead, intending to use it as a hostel for friends and family of injured service personnel receiving treatment at a nearby MoD facility. That needed planning permission for change of use and for the installation of a wheelchair ramp at the front door, and that planning permission was refused after nearby residents complained that the proposal would lower the tone, increase noise, attract criminal types, et cetera.

Mole Valley is arch-Conservative. It is not an area which is suspicious of the Armed Forces, and the local MP Chris Grayling was in support of the application. Even so, its councillors couldn't be doing with that hostel.

How are the members of a Labour-controlled council which includes longstanding CND-ites (people like Jeremy Corbyn), longstanding anti-Conservatives (people like Jeremy Corbyn), and a handful of earnest environmentalists (people like Dr Caroline Lucas) going to vote on a nuclear power station?

 
dr.bob
1312867.  Fri Feb 08, 2019 4:51 am Reply with quote

tetsabb wrote:
One Nissan Leaf, two or more Nissan Leaves, Shirley?


Good point. I'll try and remember that in future :)

 
dr.bob
1312870.  Fri Feb 08, 2019 4:58 am Reply with quote

cnb wrote:
Just out of interest, do Mercedes offer the same warranty everywhere? Tesla have a warranty on Model 3 batteries which appears to be the same wordwide (70% after 8 years or 100,000/120,000 miles depending on the exact model). Their Powerwall warranty, however, is 80% after 10 years in cold countries and 70% after 10 years in hot ones.


I'm not sure how the Mercedes warranty translates as I've only been able to find a copy of their North American version. However, that warranty states that the warranty does not cover damage or failures resulting from or caused by:

Quote:
Exposing the vehicle to ambient temperatures above 140F (60C) or below -22F (-30C) for more than 24 hours or above 104F (40C) or below -13 F (-25C) for more than a 7 day period


So I imagine that would cover them against particularly hot or cold countries.

 
dr.bob
1312872.  Fri Feb 08, 2019 4:59 am Reply with quote

PDR wrote:
Alexander Howard wrote:
Tesla coils on the side of the motorway which charge cars as they go along, and invoice the owner at the end of the month.


Have you any idea of the field strengths required to achieve a viable magnetic circuit over that kind of range? It would not only be hideously inefficient, but it would melt the rest of the car (and anyome in the vicinity) in the process.


Quite so. A much better solution would be to bury the coils just under the road surface. That way the induction currents would have much less far to travel in order to transmit enough power to the car to recharge the battery as you drive along.

 
crissdee
1312874.  Fri Feb 08, 2019 5:07 am Reply with quote

Technically, undoubtedly so, but it would mean digging up every mile of road in the country, or at least all the main routes, presumably every lane of dual carriageways.

That might take some time, and cause a few delays.....

 
cnb
1312877.  Fri Feb 08, 2019 5:17 am Reply with quote

suze wrote:
How are the members of a Labour-controlled council which includes longstanding CND-ites (people like Jeremy Corbyn), longstanding anti-Conservatives (people like Jeremy Corbyn), and a handful of earnest environmentalists (people like Dr Caroline Lucas) going to vote on a nuclear power station?


I don't think it really matters how they vote. There are a limited set of reasons for which a council can refuse planning, and "the local people don't like it" isn't one of them.

If a council refuses permission, the developer can appeal to the Secretary of State, who will appoint an inspector to make a final decision.

The inspector is the one who will call a public enquiry if he considers it necessary, and as we've already discussed, the first inspector to be appointed would certainly do so.

For any subsequent application, though, the inspector would assess whether there was significant new evidence or special circumstances not covered in the initial enquiry, and if not would overturn the council's decision.

 
dr.bob
1312882.  Fri Feb 08, 2019 6:08 am Reply with quote

crissdee wrote:
Technically, undoubtedly so, but it would mean digging up every mile of road in the country, or at least all the main routes, presumably every lane of dual carriageways.


Of course, making it economically viable would be a major challenge. However, from a technical standpoint, it shouldn't be too crazy.

 
cnb
1312884.  Fri Feb 08, 2019 6:23 am Reply with quote

dr.bob wrote:
crissdee wrote:
Technically, undoubtedly so, but it would mean digging up every mile of road in the country, or at least all the main routes, presumably every lane of dual carriageways.


Of course, making it economically viable would be a major challenge. However, from a technical standpoint, it shouldn't be too crazy.


It might be cheaper and less disruptive to install a wire grid above the road, and equip vehicles with a pickup pole, something like this:

 
dr.bob
1312887.  Fri Feb 08, 2019 6:45 am Reply with quote

dr.bob wrote:
Surely a greater range comes from developing battery technology.


Oooh, something I forgot to add yesterday. As well as the impressive development of battery technology that's occurring now that vehicle manufacturers are pouring all the R&D money they used to spend on diesel cars into EVs, another factor that defines a car's range is fuel efficiency (as with any car). Clearly, a certain battery size will hold a certain amount of power, but it's what the car does with that power that's important.

As an idea of the variability currently available, here a link to a study which examined the efficiency of 10 electric cars around Barcelona. They found that a new-generation Nissan Leaf will require 16.3 kWh to travel 100 km, while a Hyundai IONIQ only needs 12.2 kWh to travel the same distance. In other words, if you were able to magically move a Nissan Leaf's battery into a Hyundai IONIQ, your range would instantly increase by about 25%.

 
PDR
1312888.  Fri Feb 08, 2019 8:07 am Reply with quote

Firstly I'm going to hold my hand up and admit that some of what I posted was based on the view when I looked into this a couple of years ago which does not represent the current state of the art. Also where I had taken some studies to represent typical usage I hadn't appreciated they actually represented more extreme corners of the usage envelope. So a big apology for that. But I still think a lot of the points are valid.

dr.bob wrote:

Surely a greater range comes from developing battery technology. As an example, the 2012 model of the Renault Zoe was powered by a 22 kWh battery with a weight of 275 kg. Four years later, the new Zoe was launched with a 41 kWh battery. This very-nearly-doubling of energy capacity (and, therefore, range) weighed in at an impressive 300 kg, very nearly the same as the older model. More power, more range, virtually no increase in weight, so your logic above doesn't apply.


I think this is a "yes and no" thing. All of the forseeable battery EV developments are based on the same Lithium-Cobalt battery chemistry. This chemistry has delivered energy densities of around 220Wh/kg for many years, and hasn't changed much. Technological improvements have reduced the cell impedance, allowing higher peak charge/discharge currents, but they haven't changed the actual energy density.

What HAS changed is the pacjkaging of the cells into vbehicle battery packs. The early lithium cells were rather prone to thermal runaway for reasons that were not understood (google "lithium battery fire" for examples), so the car battery packs were packaged with extensive physical and thermal containment, which made them heavy. The 22kWh packs of the earlier Nissan Leaf and E-Niro had had heavy containment and so their net energy density was only 75-85 Wh/kg. As the cell failure modes became better understood it became possible to mitigate failures with better charging strategies and more extensive cell instrumentation to monitor and manage the current,voltage and temperature of the individual cells in the batteries. This made it reasonable to reduce the physical containment making the batteries lighter for a given capacity or allowing bigger cells for the same weight. That's how the E-niro's later pack achieved the 136Wh/kg - they put bigger batteries into a less rugged box.

Tesla take a different approach in using round-cells which are bulky but actively cooled (and actively heated in cold weather) to get to their claimed ~150wh/kg, but there is a view that they really should include the weight of the cooling/heating system in that number to compare apples with apples.

The most extreme usage would probably be the energy store of a current[sic] F1 car. These weigh 20kg (including instramentation and management electronics) and are allowed to deliver a maximum of 4mJ(1.11kWh) per lap which is in the form of no more than 160bhp for no more than 33 seconds [this is a simplification because another part of the system can capture, store and redeploy more electrical energy and part of the synthetic turbo-compounding system but that doesn't affect this number]. Teams are cagey about how much actual capacity they carry on the car because they trade-off carrying additional capacity for weight to get their prefered balance of ability to do extra laps without recharging, but I've been led to believe that one of the main contenders carries battery capacity for 3 laps in Strat-1 (no recharge) mode, which would mean 3.33kWh and 166wh/kg. We can reasonably assume this is close to optimum because F1 designers will want to have the minimum weight that will reach the finish line, although there might be some additional structure weight to stress the energy store for the "~5g on most axes" environment of an F1 car. But that's indicating that future gains in energy density are likely to be small unless/until we gat a step-change from a new battery chemistry - like we had when we shifted from nickel chemistries to lithium ones. Efros might be better placed to suggest whether that's likely.

Now I absolutely take your point about Jenny wanting to look to potential futures, but I feel that we would want to have at least some basis for suggesting that the future potential we discuss is something that is likely to happen. It would be very easy to talk about a future electric vehicle with a 20kWh/kg energy store and how terrific it would be, but unless we can see at least SOME plausible reason for believing it to be on the cards it's just a fantasy rather than a discussion IMHO.

Quote:
Two things here. Firstly the 100kW "standard" is Tesla's invention and has been around for a while now. The majority of "traditional" car manufacturers are keen to be able to trump Tesla, which is why they've already standardised on 175kW chargers and some (starting now with Porsche) are intending to develop 350kW chargers.


Good point. It's my understanding that the 100kW charger standard arose from the type of substation needed to feed a set of 6 chargers on a forecourt and how it would jump to the much more expensive higher-voltage one if you went to bigger chargers. But I now can't find reference for that so I have to wonder whether I made it up as an assumption - there certainly WILL be a cusp in the plant cost/power curve but I can't find out whether I had calculated/researched this or just assumed it so you're right to dispute it!

I'm now going to potentially annoy you by saying something different to what I said before. To be clear - I'm not suggesting this supports my previous comment - it's a different point (I'm labouring this because I don't want you to think I'm trying to twist what I said).

If we accept that the 100kW charger *isn't* a limit then what is? There are limits to how fast you can charge and discharge batteries which are usually expressed in therms of "C-rating". In this instance the "C" refers to "Capacity" in amp-hours (not watt-hours). A 1C rating means a battery can be charged at a current which would achive it's capacity in one hour. To to charge a 10Ah battery at 1C would need a charge current of 10 amps. C-ratings are a useful way of looking at charge-discharge ratings because they are independant of scale (battery size) and configuration (voltage vs wattage). C-ratings are limits of both the chemistry and the physical cell construction becuase they are driven by the cell electrical and thermal impedances (ie how much heat is produced by plate currents and how easily the plates can dump that heat, all in respect to the maximum temperature the chemistry can tolerate). A lithium cell charged at 1C will take nearly two hours to full charge because the charge current has to be reduced for the last 20-33% of the charge, and that's where the whole "80% fast charge" thing comes from.

Most lithium cells can be safely charged at 0.1-0.3C without significant problems. You CAN charge them at higher rates, especially with active cooling, but when you do you get local heating in the plates due to high local current densities, and this causes electrolyte film delamination which reduces the capacity and increases the impedance. The more you do it the greater this problem becomes because the reduced capacity increases local current densities which increases the local heating and so on. That's why fast charging reduces battery life (as in this study) which the manufacturers have had to mitigate by limiting the amount of fast charging the owners can do (eg as reported here).

Again, the extreme example is the F1 energy store, which has lots of instrumentation and very careful management together with a lot of active cooling. These batteries are discharged at over 100C and charged at around 20C, but they must only last (by regulation) six race/qualifying sessions plus the FP3 running, which amounts about 1,400 miles - many don't make it and have to be changed early (which incurs a penalty).

So whilst there may be higher-power chargers in the future I think they will be to allow bigger batteries to be charged in the same ~1hour period rather than allowing shorter charge times.

As an aside - the C limit is a characteristic of the cell chemistry. The previous nickel cells and even lead-acid cells have MUCH higher C-limits. You can safely charge wet-cell NiMH cells at over 1000C (assuming they don't boil the electrolyte) without ill-effects. I have always assumed (but it's an assumption) that the limit on the Lithium-Cobalt cell is due to the use of a solid polymer electrolyte rather than a liquid one becuase I could believe that the liquid electrolytes can dissipate heat more effectively. But I stress that this is an assumption on my part.

Quote:

Clearly people will not have the same charging facilities in their houses that they do at charging stations, in the same way you cannot fill up a petrol car at someone's house in the same way you can at a filling station.


Absolutely, But I was looking at Jenny's use-case in the round. Her use case is to use the car to visit a friend. With a liquid-fuelled car she can drive to ger firend, stop at a petrol station to fill the tank (5 mins) and then go to her house to have a natter for an hour before driving home. With the EV car she must drive to the place where the charger is, put the car on charge and then find some other means of transport (eg a bus or taxi) to get from the charger to her friend's house, and must then return to her car by bus/taxi/WHY at the specific time the charge finishes to retrieve it before she incurs "bed-blocking" penalty charges for leaving her car there while she and her friend discus brexit, trump or other neutral topic. How practicable/burdonsome this is depends on how far her friend's house is from the nearest fast-charger and how frequent/efficient the available transportation is. If it's a 20minute bus ride, or one that only runs every hour, then she only gets a few minutes to discuss Trump'd deeply-held humanitarianism before she has to set off to retrieve her car again.

The EV concept works really well for people who live in cities or major urban areas, but IMHO the use cases become more difficult for rural dwellers, or people who live in widely separated small towns.

Quote:
Where does this "2-3 years" figure come from?


I really must hold my hand up here and state I was simply wrong! My understanding was flawed partly becuase it was out of date, partly because I hadn't appreciated that some reports related to extreme behaviour rather than typical behaviour and partly because my brain seams to have rather exaggerated the issue. Please accept my apologies!

Quote:

Finally, a point I missed earlier. When you said 'I don't know about the E-niro but most of the others like the Nissan Leaf only allow one or two consecutive "fast" charges before you have to do one or more "slow" charges to protect the battery.' it turns out this is not true.


I have to say it IS true that Nissan restrict the number of fast charges you can do - I provided the source for this above (it's here) which confirms that the software does what I said it did, and also that some people have experienced relatively large battery degradation in as little as a year. At that time Nissan said that it was due to high ambient temperatures rather than fast charging, but if that was the case why did they restruct the use of fast-charging via the battery management software?

I do think it's interesting that the report I cited is actually the 50,000 mile update of the one you cited, so we're to some extent on common ground. This report does show that there IS a noticeable deterioration from fast-charging, but it is nowhere near as big as I suggested it was. No excuses - I was just plain wrong on that.

Quote:

But surely that has its own inherent infrastructure challenges. Plus it's an unproven technology, while EVs are not only tested and proven, but are seeing large-scale uptake in many parts of the world.


We already have near-neighbour infrustructure for mass distribution of gas. liquified gas and petrol/derv, and the fundamental concept (go to distribution point, refill tank in a couple of minutes, drive away - supply distribution point by road tanker or direct pipeline feed). And the hydrogen-fuelled ICE is essentially identical to the petrol/LPG-fuelled ICE in all respects other than the fuel tank itself (and even that is almost identical to the LPG-fuelled ICE). So I would suggest that these are pretty mature technologies which have minimal implementation risk - at least in my view!

PDR

 

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