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Battery Design and Info
Can someone explain how the relationship of range to battery size is possible? 250 miles on a 25kWh pack, 400 miles on a 40kWh pack, 600 miles on a 60kWh pack and 1,000 miles on a 100kWh pack doesn’t seem to account for the extra weight of the larger batteries. Exactly how can the 1,000 mile range Aptera have the same efficiency as a 250 mile range Aptera when it’s lugging a battery that’s four times bigger and four times heavier?
Speaking of batteries, how heavy are all four packs? I read somewhere a Tesla 85kWh pack weighs 1,200 pounds.
- 121 Replies
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Battery Design and Info
updated 1 month, 1 week ago 67 Members · 121 Replies -
Hi There,
Just wondering whether Aptera is in a position to provide an update regarding the battery technology to be used. I’m aware of some developments with graphene aluminum-ion battery technology, and was wondering whether it might be suitable for Aptera. The claim is that they charge up to 60 times faster than the best lithium-ion cells and hold three time the energy of the best aluminum-based cells. Plus, they are claimed to be more sustainable and easier to recycle, due to the stable base materials used in the manufacture of the batteries.
Thoughts?
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There are so many different battery designs and chemistries being announced by universities. But as always, the step from R&D to mass production is HUGE. And often it is simply not possible to scale up production, especially at a competitive price.
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I would like to hear more about the Batteries they are planning to use in Aptera Vehicles. We have to be getting more info as Beta vehicles are being produced & assembled and they must be designing and utilizing production intent Battery supplies. They are obviously not producing their own batteries and have strict power and weight requirements in order to make their stated range goals. I feel like it is overdue time to have a deep-dive on Battery and Battery Management system they will be utilizing. Any chance Munro & Associates will be helping them out as both the Low Voltage and High Voltage control systems has been a big point of issue with a lot of EV vendors even if the outside of the cars do look good.
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I’m wondering if Aptera will be using any of the advanced insulation technologies for the batteries ?
Things like the Panasonic Vacuum insulated panels (R45 of thermal insulation from only 15mm thick) .. or other similar advanced options that insulate very well without consuming allot of space or weight.
Some other modern BEV can spend allot of power/energy on the battery counteracting the outside air temperatures .. like a house cooling it in the hot summer days , and heating it in the cold winter nights .. and like a house , passive measure like insulation make a very big difference in how much energy needs to be spent .. but many other BEVs seem to put nearly no heat insulation in at all .. and like a old drafty house they have to spend allot of power/energy to heat it or cool it .. I’ve read the Tesla3 for example has ~3kw of battery heating capacity .. and sure it isn’t always used on every winter night at full power , etc .. but .. like insulating your house .. closing windows when the heat is on in the winter .. putting on a coat when you go outside in the winter .. insulation just seems like a much more energy efficient way of approaching that.
With the Aptera’s lower operating consumption per hour or per mile (better aero , weight ,etc) , tat means less waste heat .. thus less available to ‘self heat’ the batteries with .. and smaller lighter batteries also mean less battery thermal mass , while parked (unplugged) over cold winter nights or 3 day weeks and such .. but to me .. modern insulation options seems like a perfect solution.
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I’ve always been curious about the sizing of the battery packs. Wouldn’t equal size battery modules of 25 kwh make more sense? Then the battery packs would be multiples of 25, 50, 75, and 100 kwh, not the odd 25, 40, 60, and 100 kwh now offered. Would make manufacturing of battery packs more efficient with build up of identical 25 kwh battery modules and probably lower production cost. Am I missing something about the advantages of having 40 and 60 kwh battery packs? Is it a marketing advantage?
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They have already reported ‘active battery thermal management’ .. which means they already have a heat exchange medium (air or liquid) inside the battery compartment to add or remove heat to the battery as needed .. the only place the Aptera has to remove heat would be the aero skin exterior radiator .. one could have the layer of insulation in the composite sandwich between the battery case and that skin radiator .. like putting a hot oven (radiator) right next to and touching your colder fridge (air conditioned battery/cabin) .. We know those two are right next to each other on the bottom of the car .. To avoid a bunch of wasted energy by the two fighting each other .. It would be best if there was a highly thermal insulative layer between those two hot and colder items … For my 2 bits .. the best option to give the most insulation in the smallest space and lightest weight , to do that would be something like those super thermal insulative vacuum insulation panels Panasonic makes.
<div>When sitting in the winter cold teens or single digits over night .. or over a holiday weekend .. without insulation .. or wasting allot of energy keeping it warm .. the battery will drop to those cold ambient temperatures .. ice cold batteries have poor performance. Which is why every BEV on the market has a winter time battery heating system .. but my 2 bits .. a well insulated battery will need far less of that energy to keep it warm in winter .. and insulation also vastly reduces the amount of energy needed to keep the battery cool when parked backing in the hot summer sun all day .. or keep the battery cool from the hot skin radiator right next to it when under heavy load / use during those hot summer days.
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I would really like to know where Aptera is getting their batteries from. Maybe I missed it somewhere – if anyone knows please post. Other suppliers would also be interesting to know. Thanks
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Aptera has a proprietary format for battery packs assembled from the same batteries in Tesla Model 3’s (Size 2170). They will buy the batteries and assemble the packs as their process is faster and more efficient therefore less expensive and time consuming.
Great for us too have it done faster and cheaper.
Glad there is a consistent emphasis on efficiency!!!!!!!
Before you ask, I don’t know the supplier or if the batteries will be the newer LFP (Lithium Iron Phosphate)
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According to some YouTube videos the battery Aptera uses is the Samsung INR21700-50E, which is a cobalt based cell and everything but innovative or friendly to the environment ! Additionally it is a flammable battery type, that makes an Aptera less safe to drive. Aptera, please rethink and use a sustainable technique like LTO or at least LiFePO4 !
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To get optimal charging conditions the battery pack should be at an optimal temperature especially when charged at high charging levels. Not that I will ever charge at that level but I’m curious. Does the Aptera have some kind of smart battery temperature management system on board to ensure optimal battery performance and charging?
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BMS tech has come a long way since the early days of Lithium packs.
I’d be stunned if Aptera’s BMS did NOT have provision for working with the pack at different temperatures while charging or discharging. Some of the engineering types on the forum will probably respond to this question with an in-depth answer for you, Elzo.
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Do you guys think the cooling system is the same on all battery variants? I am referring to the micro channel tubes they have referred to, and the rest of the systems volume (just not immediately around the batteries).
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I suspect the cooling system’s ability to dissipate heat while charging is the reason we only have 50 kw DC fast charging. Most EVs have better (ie 150-250 kw) and it would make a great marketing headline along with the crazy 1000 mile range. Very likely the ability without traditional radiators and fans to get rid of the heat is the limiting factor. If it could work without major design sacrifices (ie weight, complexity, expensive) they would love to be able to get 400-500 miles of range (within the 20-80% segment) in 10 minutes; instead its an hour.
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I don’t think even all new EV’s have pre-conditioning of the battery for fast charging. I’ve seen complaints on youtube of Kia EV6:es not getting maximum charge rate from the start, presumably due to cold battery. I know Tesla and Polestar, after a recent update, will heat the battery if necessary before arrival when navigating to a fast charger.
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I think Tesla may have made a slight strategic error, shock horror. It seems battery technology is developing at pace, solid state, alternate cathode anode electrolyte. Therefore, having the battery as part of the structure is good for strength, manufacture cost, bad for flexibility, adaptability, future possibilities. I wasn’t a fan of battery swap until now, of course battery life has proved itself but Aptera bodies won’t rust so any glitch in battery is only possible problem. Most Tesla owners will probably just buy a new car, but for sustainability? Does Aptera have a fairly easy battery swap like Nio or Renault Zoe?
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Hi Ian,
Great question! While we gain some structural benefits with the battery bolted to the body, our pack is not considered structural. Battery swaps will be possible as the pack can be removed without compromising the integrity of the vehicle body. 🙂
Driving solar mobility forward,
Audra
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What is the lifetime of the batteries
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Hi everyone! Many cells can fail in our pack design before things need to be replaced. And if replacement is needed you would only need to replace the pack itself. The replacement costs will vary but be far less than any other EV as our packs are smaller for a given range. We will strive to make them affordable for upgrades in the future. You will not have to worry about replacing the battery or battery cells for at least 10 years. We expect to offer a 10-year warranty on the battery pack and for the battery to live much longer than that. More exact figures will be shared prior to launch! Thank you for all being a part of our movement to transform the world of transportation into a less destructive and more creative place.
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Battery life anxiety seems to be overtaking range anxiety, yet we still have no car-specific experience. Calma, gente.
From what I have noted in the 18 months I have had a BEV, actual battery life is varied and hard to precisely predict. Generally, “birth defects”, such as the Chevy Bolt, is a concern covered by 1) use of not-state-of-the-art technology and 2) warranty. Aptera’s 2170 NMC cells are not state-of-the-art. Aptera’s proposed 10-year warranty covers both birth and adolescent defects.
Wear and tear failure is far too complex for non-specialists (like me) to predict with any sort of precision. Charging low and slow seems better than full and fast, but I’ve seen no specialist brave enough to quantify that effect. Does it range between 1% and 5% per year? Probably, but how controllable is it? The Aptera (solar) trickle-charger is excellent for “slow” and the car’s efficiency allows slow charging as a matter of course. There will seldom be need for medium (Level 2) or fast (DC) charging, but I won’t worry when it is useful.
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Hopefully this can still be seen. What effect does the solar charging have on battery life? I don’t know much about these batteries, but do they have the issue where constant charging lowers battery life? I believe the Tesla is suggested to drop to around 10% every time, then charge, to extend battery life.
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A few thoughts on that:
Generally the lower the charge rate the lower the “wear” on the battery. The lowest L1 charge rate on a typical modern EV is going to be 1200-1600 watts (depending on your EVSE). The most you will get out of the current PV configuration on the Aptera is 700 watts. Pushing awful close to negligible there.
We are liable to be able to set max SOC for charging off a plug and separately off the built-in PV so the user will be able to set those limits where they think prudent for their own battery degradation risk assessment.
As an anecdotal example, my Leaf has about 130k miles on it with minimal battery degradation (and everyone thinks Leaf batteries are the worst). My Aptera will have a 40kWh battery instead of a 24kWh battery and go 10 miles per kWh instead of the 4 my Leaf gets. A little math informs me that my Aptera might suffer a similar amount of battery degradation after 541,667 miles. I only drive about 20k miles per year. That’s rather more than the US average. Somehow I’m just not that worried about battery degradation (at least due to moderate charging practices) and doubt that anyone else should be either.
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https://www.youtube.com/watch?v=0Klxngp4H8U
New video is up for 41kwh battery!
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Looks like the 400 mile version will have a 41 kwh usable pack.
6 modules
416 cells per module
2496 cells total.
– If these are Samsung INR21700-50E battery cells then:
5ah per cell means 0.018 kwh per cell so 44.928 kwh total. So maybe 3kwh is unusable.
So each module is 7.488 kwh total or 6.833 kwh usable.
I’m guessing they’ll make these packs:
4 module (27.3 kwh) pack
8 module(54.664 kwh) or 10 module (68.33kwh)
14 module (95.662 kwh) or 16 module (109.33kwh)
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As most EV traction packs have a buffer of between 10 and 20%, that would put Aptera’s capacity somewhere between 45 and 50 kWh. So your 44.9 figure could be right on the money!
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Based on this data I projected the numbers based on the math. I am really having issues making a combination that makes the ranges come out roughly correct.
The biggest issue is that if you assume modules will be constant having 3 in the 250 mile underperforms and 4 overperforms. By having a low pack weight overhead (15%), high battery reserve (15%) and very low base weight of 950lb (without battery or driver) others are 10% over EPA rating and the 3 module 250 mile is at only 240 miles. It could be that different packs will have different module sizes because 3 or 4 modules of this size gave either far too little or too much range. If you plugged the constants from motormatchup and used a 60 mph speed is roughly EPA the range would be more like 530 miles for this “400 mile” pack. The 1000 mile version might need as many as 18-20 modules (134 kwh) weighing 1400-1600lb.
Note: Make a copy to play with the numbers – please share it if you can get closer. Only the Aptera Battery Sizes tab has these new more complex calculations. Orange fields are the numbers being fed into the calculations that can be changed. Edited with Ken’s suggestion for more battery reserve but the 400 is still overperforming but adding modules or weight changes throws the number curves off even more for the other ranges.
Important: These numbers contain a ton of assumptions and estimates. Only the Cd and these pack details are actually confirmed.
PS: the forum ate my comment on edit multiple times… Thankfully I always backup because it isnt the first time. Tweeked the numbers again and again to get as close to inline with intended ranges.
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Aptera Owners Club did a video breaking things down. https://www.youtube.com/watch?v=nXNYlMqQ0Jk