Kia using SK Innovation NCM Li-ion cells in Soul EV
24 February 2014
Kia is using lithium-ion polymer battery cells supplied by SK Inovation in the battery pack for the new Soul EV (earlier post). The pack, featuring an energy density of 200 Wh/kg (on the high end of specific energy ratings for current EVs), is the result of a three-year joint development program between Kia Motors Corporation and SK Innovation in Korea. The Soul EV offers a driving range of around 200 km (124 miles) on a single charge.
Engineers from Kia developed the pack with 192 SK lithium-ion polymer battery cells in eight modules, for a total capacity of 27 kWh. The pack incorporates advanced thermal control technology to maintain individual cells at optimum temperature and structural design to enhance crash worthiness.
Nickel-rich NCM (nickel-cobalt-manganese) cathode material is used in the mass production of the battery cells for Soul EV. High performance electrolyte additive and anode materials were also developed to meet various performance requirements (such as safety and lifecycle), while maintaining high energy density.
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| One of the SK Innovation cells. Click to enlarge. |
In addition, a special safety & secure separator is used in the Kia Soul EV’s battery cells. The separator determines the safety and the charge/discharge speed of the battery. It has improved thermal resistance, which helps to keep the cell secure from exposure to heat or fire by preventing the shrinking of the separator if the temperature of the cell increases beyond normal levels.
Together, the low electrical resistance battery cell, proper battery system thermal control and accurate state-of-charge calculation improve the charging performance, thereby enabling a fast charge time of 25 minutes (100 kW DC) or 33 minutes (50 kW DC). Full recharge time, depending on power source, takes up to five hours (6.6 kW AC).
The electrolyte additive used in the Soul EV will prevent the degradation of battery performance at both low and high temperatures, expanding the temperature range of the battery usage and reducing the fluctuation of the driving range according to the weather.
The Soul EV features a battery heating system which warms-up the battery while the car is plugged into the grid, prior to use. This helps to maintain optimum battery performance regardless of external temperature.
For maximum active safety the battery module is fitted with an overcharge protection device that cuts the high voltage circuit if ever the battery cell swelling phenomenon should occur due to overcharging.
Optimization of the raw materials used to create the cathode morphology control and surface coating, the anode surface coating and electrolyte additive, plus the excellent mechanical strength of the separator, provide for the durability and safety of the cell.
The EPA rating will not be better than the 75 miles that the Leaf 2013 version got. It is less aerodynamic than the Leaf and that will undue the added range from the 27kwh battery rather than the 24kwh battery of the leaf. Now drive this in cold weather in a hilly terrain and you get 50 miles range. Add a safety margin of 7 miles in order to allow for a wrong turn on the highway and you get 43 miles of practical range in worst case scenarios. It is therefore useless for most. A small car like that needs a 75 kwh battery in order to do 150 miles even in worst case situations.
Posted by: Account Deleted | 24 February 2014 at 06:46 AM
Sorry. I got the Leaf range wrong from an erroneous Wikipedia source. A better source is fueleconomy.gov where the Leafs 2014 range is put at 85 miles. Does not change the conclusion of my post though.
Posted by: Account Deleted | 24 February 2014 at 07:09 AM
Double sorry. The wiki source was good enough. 75 miles range for the 2013 Leaf and a much improved 84 miles for the 2014 Leaf model is the true data.
Posted by: Account Deleted | 24 February 2014 at 07:13 AM
This does not meet overall performance of the current 2-2-2 pack used by Tesla. It looks more like a 1.5-1.5-1.5 pack. However, it seem to have valuable properties such as very quick charge, over charge protection, wider operation temperature range, longer potential live, etc.
It may turn out to be one mini step ahead of the Nissan Leaf pack?
Posted by: HarveyD | 24 February 2014 at 07:41 AM
Henrik, once again you are making a very important observation. The Hyundai Group seems to have some difficult with mileage/range claims -- see 2 Nov Forbes article
http://www.forbes.com/sites/jimgorzelany/2012/11/02/epa-slams-hyundai-and-kia-for-overestimating-mpg/
and other Jim Gorzelany posts on this topic.
Is it possible to stretch the Soul to 200km? Sure you can. There is also a 200km club for Leaf enthusiasts with a fairly large membership. But this is extreme hypermile-styled driving that annoys everyone around you as you motor around gently with windows up and no HVAC, radio, lights, etc. It's a meaningless number.
The Soul weighs in about 50kg or so lighter than the Leaf; otherwise, it seems to have no advantages. It doesn't use a heat pump for better HVAC efficiency (outside of extremes). Hard to imagine better rolling loss numbers than the Bridgestone Ecopia, and as you point out the Cd is probably higher. Finally the Leaf's regen (assuming the driver elects to use it) is about as strong as the battery can effectively use. Currently the Leaf advertises 84m/136km "typical" range (up from the 73m/118km on my '12 window sticker, as you note). I could believe something around 90m/145km for the Soul on the EPA cycle.
But as you state real world can be tough. Even if I charge to 100% and pre-heat, Midwestern winter still rips away a big chunk of mileage. My young 12 bar battery will give me 50 miles (one bar remaining) in suburban-type driving if I am "judicious" with heat, modulating the on/off switch to prevent fogging and provide adequate comfort. If I'm wearing wool socks and boots, I can stretch this another 3-4 miles; with anyone else on board I leave the heat/defrost on and lose 5 miles or so. So 45-55m (about 75-90km) is the genuine hard winter range. The Soul will probably net another 8-10%.
I wouldn't call this "useless". I mostly work out of the house so I plug in frequently to nudge the battery back up to 80% or so variously throughout the day. Since I got the car my average daily odo reading is just over 36m/58km. Multiplied by 365 that's almost exactly the same as the average annual mileage for US drivers (13,476m) according to .gov numbers. Those who don't live on the frozen prairie could go further.
But it is not very flexible, I admit, and another few miles isn't going to excite a surge of Soul EV drivers.
Posted by: Herman | 24 February 2014 at 08:17 AM
Harvey:
"However, it seem to have valuable properties such as very quick charge..."
Not really. The Soul "quick charge" is just CHAdeMO-based. My Leaf has the same receptacle and can pretty much duplicate the claimed Kia rate (about 30 minutes). As for the ability to withstand repeated QC: there is a thread on mynissanleaf.com discussing a long-term test comparing cars charged on normal L2 vs. QC. In 40,000 mi the capacity degradation was roughly 3 points worse for the QC group -- really a small number for something generally considered "abusive" to the battery.
"...over charge protection..."
This is really an overstatement on Hyundai/Kia's part, probably to attract EV skeptics who are worried about everything. ALL current EVs have very good protection in their charging management systems.
"...wider operation temperature range, longer potential life, etc."
I'll believe it when I see it. The Soul battery is still air-cooled, just like the Leaf. This is a rational manufacturing cost choice and it doesn't make the battery "bad". But it's clear that a properly designed thermal management system (Tesla, FFE and Volt) that minimizes hot spots, levels out spikes/valleys and in general reduces stress on the cells. Yes, the Kia chemistry is different, and that's important. Still I think we should wait for the Phoenix and Minneapolis users to report in before we make that claim.
Finally as to the "x-x-x" evaluation of this battery, I'm guessing you are referencing Argonne Lab's JCESR project to get 5 times more powerful 5 times cheaper in 5 years (5-5-5)?
As for "cheaper", the Soul EV price hasn't been announced but the whisper number at the Chicago Auto Show was about twice the price of the base Soul, or USD30k: not really any better than the Leaf for a 10% capacity improvement.
Five times more powerful (I'm assuming they mean energy density)? Hyundai claims 200Wh/kg, which would make this battery about 130kg. Wow: the Leaf's 24kWh pack comes in at 294kg, or 80-ish Wh/kg. Amazing! Yet the Soul EV, which is about 25cm shorter than the Leaf, weighs only 50kg less. Hmmm... There's more:the Tesla Model S pack at 85kWh weighs in 600kg, so it only manages 140Wh/kg. Suspicious yet? You should be. What are Hyundai measuring to claim 200Wh/kg? Just the cells? The reality is they might be achieving 10-15% more specific energy than the Leaf.
So overall, using the JCESR terminology, you are seeing a "1.2-1-2" battery (the two coming from the fact that it will hit the market 2 years after DoE's $120M award to establish the JCESR project).
Posted by: Herman | 24 February 2014 at 09:29 AM
@Herman:
The Leaf at the cell Level is around 150wh/kg.
Hyundai are probably talking about 200wh/lg at the cell level, so around 25% lighter than the Leaf pack would be for the same kwh, so for the 300kg Leaf pack if you run the numbers ( 300*0.75*[27/24]} you come out to around 250kg, so saving about the difference in the weight of the two cars.
Posted by: Davemart | 24 February 2014 at 09:52 AM
Thanks, Davemart. Makes sense. To be fair the Leaf also has Aluminum doors and hood, which also allow it to be larger than the Soul and not weigh much more.
Posted by: Herman | 24 February 2014 at 10:04 AM
All other factors excluded, the Kia battery's 200Wh/Kg energy density shows improvement over the current Leaf battery which is 120Wh/Kg. In theory and all things equal, a Leaf with a real World range of 60 miles would increase by 60% to about 96 miles,running a Kia battery.
Rumour has it Nissan's next Leaf will go 150 miles, I suspect that will be about 120 miles because of the exaggerated PR hype by Nissan. Nevertheless, that's a doubling of energy density to about 240Wh/Kg.
Perhaps some day a used Nissan Leaf with an upgraded battery pack will prove to be a fairly priced EV. Right now a used Leaf is a risk and the current poor range figures affect the resale price negatively.
Posted by: Lad | 24 February 2014 at 10:12 AM
@Herman I retract my "useless" statement. I was wrong because a 24kwh BEV is useful even for most people. Especially if the price could be much lower, like, less than a similar powered gasser because a 24kWh BEV can do less than such a gasser.
I might have lost my judgment for a moment because I am really very disappointed that Tesla is the only current BEV maker that focus on long range BEVs. It is, as if, every other BEV maker think it is impossible to make a BEV with over 200 miles real word driving range.
I believe the Tesla battery cells are 240Wh/kg. However, Tesla is also able to do a better job of packaging their cells because they are much smaller about 1/10 the capacity of the large cells used by all other BEV makers. That means Tesla can safely pack a cell with very little fire protection material between the cells in order to prevent thermal runaway in one cell from propagating to neighboring cells. The end result is a battery pack with even higher gravimetric energy density than could have been achieved with larger cells with the same energy density as the cells Tesla use. Again only Tesla seems to have figured that out.
Posted by: Account Deleted | 24 February 2014 at 10:45 AM
Herman, you have a lot of facts wrong about the LEAF.
1. The battery specs and range is basically unchanged so far from 2011-2014 model years. There have been some tweaks from 2013-on, but mostly packaging improvements and no significant change to the battery chemistry itself.
2. What has changed is the way that the EPA tested and thus rated the cars. The 2011-2012 LEAF used a different test than the 2013-2014 LEAF. The 2014 LEAF removes the 80% long-life charge setting, so it appears to get a boost over the previous LEAFs, but in reality it is the same.
3. Aluminum body panels are only available on Japan produced LEAFs. When production was moved to the USA for the 2013 model year (at least for the USA market), doors and hood went back to steel.
Posted by: Dave R | 24 February 2014 at 11:03 AM
Dave R, let's start with the Aluminum. 2014 doors are in fact back to steel (I have an Oppama-built car, so this was indeed news to me).
However, I think you misunderstood this part of my post:
"Currently the Leaf advertises 84m/136km "typical" range (up from the 73m/118km on my '12 window sticker, as you note)."
That's it, and the numbers are exactly correct. All I addressed was the EPA rating. I know there's no change to the battery, and only modest changes to range/SoC display software (I just got the upgrade). My point was the RATING changed, and if we are talking about the Soul's RANGE RATING in 2014, then we should be addressing it on an apples to apples basis. The 2014 EPA RATING standard says the 24kWh Leaf is an 84m car, using essentially the same battery as mine. I do not believe the 2014 Soul with a putative 27kWh battery could have a 120m EPA RATING. That's the point.
If you can quote anything in my posts implying the newer Leaf has a different battery, please show me.
Posted by: Herman | 24 February 2014 at 11:54 AM
The Kia Soul EV is a welcome addition to the EV lineup. Although an extra 11% battery capacity is not a game changer, it's a move in the right direction and I applaud it. Around town, that extra 8 miles range is just the extra margin you need on days you have extra errands or need to drive to the edge of the metro area and back. It may not seem like much of an edge, but in real world use, it's helpful.
Posted by: electric-car-insider.com | 24 February 2014 at 12:40 PM
There is a lot of talk with BEV about the fast charge network being necessary to turn a limited primary range into a useful daily multi-charge range.
However the article and comments talk about pre-heating the battery (and car). Slow chargers would provide this benefit. Even if I had an ICE car that could take advantage I'd be plugging in in winter. Does it make sense to install slow chargers or would they be most of the cost of a fast charger?
Posted by: DavidJ | 25 February 2014 at 10:17 AM
If a Tesla gets 200 mile range with a $70,000 car and a 70 mile range EV costs $25,000, the next 2X battery improvement could change a LOT in the market. Now the $25,000 car will get 140 mile range and the Tesla could cost less or go farther, but the lower cost EV with 140 mile range will be here from several manufacturers.
Posted by: SJC | 25 February 2014 at 11:48 AM
"For the 2013 model year Leaf, Nissan achieved a 15% improvement of its EPA's fuel economy combined ratings." http://en.wikipedia.org/wiki/Nissan_Leaf
A 7%/year average range improvement via motor/electronics tuning alone is impressive. The 5-5-5 battery will likely be 5-5-10, but it's too late for Retrolicans to crush EVs this time.
Posted by: kelly | 26 February 2014 at 08:37 AM
Some range experience with Mitsubishi IMiev
In summer weather driving up to 80 KmH or 50 mph i get 105 miles range, not using the air-con or anything else
In winter this drops to 50 miles range at a temperature around freezing or a bit below.
If i park my car in the warm garage in winter 75 miles is achivable all with out using the heater, if i use the heater the range drops by 20 %
Posted by: gideon goudsmit | 27 February 2014 at 02:46 AM
Short range (200 Km) EV currently need about 40 kWh battery pack. Current 1-1-1 (40 kWh) packs are heavy and not that easy to package into a small car.
Lighter aluminium-composites future small EVs with Tesla's 2-2-2 current flat battery packs could get the same range with about 30 kWh.
With next generation 3-3-3 batteries, the same small EV could get the same range with a small 20 to 24 kWh pack.
Long range (500+ Km) EVs will normally be larger and will need 120 kWh packs. That will be a strong possibility by 2017/2018 with 3-3-3 batteries. It may be called the Tesla Model S-120?
Posted by: HarveyD | 27 February 2014 at 07:56 AM
Silly question? Couldn't one use a small propane heater for cabin heat? Not sure what to do about serious cooling, though. Lots of iced tea....
Posted by: E-Biker | 27 February 2014 at 11:13 AM