Category Archives: Batteries

Tesla’s First Lithium Agreement

Last week, Tesla announced they have made a deal with two companies for a mine in northern Mexico to mine Lithium products (Lithium Hydroxide, 29% Li by weight, and Lithium Carbonate, 18% Li by weight). The companies involved still need to get funding to build the mine and commence operations, but it should be a bit easier for investors know they have a deal lined up with Tesla Motors to buy all that lithium that will be mined.

The deal starts with 35,000 tonnes of Lithium initially, and may scale to 50,000 tonnes of Lithium as the production at the plant scales up. So how many kWh does that translate to?

Lithium Ion batteries vary in their amount of their elemental lithium (vs. lithium hydroxide or lithium carbonate) based on the type of chemistry and other materials present. The NCA cells found in the Model S use about 300 g of elemental lithium per kWh. This translates roughly into either 1.67 kg of Lithium Carbonate (LI2CO3) or 1 kg of Lithium Hydroxide (LiOH).

Let’s assume that its a 50/50 mix of both Lithium products, which yields a requirement of 1.33 kg of Lithium products per kWh of battery produced. At 35,000 tonnes of Lithium, that is 26.3 GWh of manufactured cells, assuming that there is no waste product from the lithium coming into the factory (this is not likely the case, so the 26.3 GWh will be the upper bound for our 50/50 assumption). The maximum initial production would be 35 GWh if 100% of the supplied lithium product was Lithium Hydroxide, and the minimum initial production would be 21 GWh if 100% was Lithium Carbonate.

At the contract maximum of 50,000 tonnes of Lithium product, you’re looking at a minimum of 29.9 GWh, a midpoint of 37.6 GWh, and a maximum of 50 GWh of battery cells for the Gigafactory.

So given the inputs and assumptions, we can estimate 26.3 GWh of battery cells to start with, and 37.6 GWh of cells at the top end of the range. If 75% of the cells manufactured go into cars, and the other 25% of the cells go into Tesla Energy products like the Powerpack and Powerwall, it would mean a production of between to 350,000 and 500,000 55 kWh battery packs for the Tesla Model 3 (55 kWh is my estimate for the average pack size sold).

Tesla’s initial stated capacity for the Gigafactory is 35 GWh of cells (and 50 GWh for battery packs – meaning 15 GWh of finished cells are delivered to the plant). However recently Elon has stated that the manufacturing capacity may be even higher than that, as they seek to more efficiently use floor space in the manufacturing process. Tesla may be able to build the same sized building, but rather than get 35 GWh of cell manufacturing capacity, they could get 50 GWh or more. Its currently unknown how much additional capacity they might be able to get, we won’t get our first look until the first phase opens in the first half of 2016 for Tesla Energy cell manufacturing.

(part of this post cribbed from my own Ars Technica comment on this same story)

As a postscript, I’m disappointed the company I had money invested in, Western Lithium, was not Tesla’s first choice for Lithium for the Gigafactory, despite that the mine for the Lithium was in the same state as the Gigafactory and less than 200 miles away. It might be that Tesla needs more than one lithium supplier, and there is still a chance for Western Lithium. And Tesla is not the only game in town either – other battery factories like LG Chem also need Lithium.

Electric Jets?

I’ve been thinking a lot lately about electric jets. With all the purported battery breakthroughs, and a discussion of what aviation might be like in 2030, 2040 or 2050.

For the battery baseline, we’ll go with Solid State Lithium metal batteries. These batteries are completely solid, they don’t have a liquid electrolyte that can oxidize and catch fire. They are currently under development, and are expected to go to smaller scale commercial production in the 2016-18 timeframe. Dyson has invested in one of the leaders in the space, Sakti3, with the hope that Sakti3 can produce cells above and beyond current Li-Ion cells. The experimental values for the weight and volume that have been developed so far are about 800Wh/kg and 1500Wh/l, compared to 250Wh/kg and 700Wh/l for the top of the line batteries today. I would expect these batteries to be widely available and inexpensive by the mid-2020s.

I first looked at a Boeing 737, and whether you could build a similar size and weight, but replace the fuel tanks with batteries, and the engines with ducted fans, and see what that would give you.

Boeing 737-800 weight of max fuel: 24,025 kg
Boeing 737-800 volume of max fuel: 29,660 liters

Replace 24,025 kg of fuel with 24,025 kg of batteries: 12,813 liters of batteries (43% of original fuel volume)
Energy storage: 19.2 MWh

Replace 29,660 liters of fuel with 29,660 liters of batteries: 48,198 kg of batteries (200% of original fuel weight)
Energy storage: 38.5 MWh

You can only realistically use the smallest value of the two, since both volume and weight are limiting factors, its about which one you hit first. In this case, its weight limited. So our new aircraft has 19.2MWh of batteries weighing 24,025kg and taking up 12,813 liters of volume (less than half of the volume the fuel used up, so there may be opportunities to redesign the aircraft and reduce its overall weight). The power these batteries could generate based on the cell weight is a maximum power of 12MW, estimating 500W/kg of cells. This estimate is in line with what today’s batteries can produce on a sustained basis.

So what kind of demands are going to be put on the battery to propel the aircraft from ground to flight? Initial take-off thrust required will be high. The Airbus E-Fan demonstrator had hub-motors in the landing gear to help get the aircraft up to speed. This reduced the load on the engines to propel the aircraft up to take-off speed. If the aircraft is running maximum throttle, then the two engines are producing about 242kN of total force. Based on the E-Fan’s substitution of ducted fans, they have 30kW = 0.75kN, or 40kW = 1kN, which means the engines would need about 10MW of power over the course of about 45 minutes to get up to cruising altitude (using 7,500 kWh of energy). Cruise thrust is about 40% of max thrust (depending on altitude, air density, etc.), so energy usage per hour of flight is 4,000 kWh, and energy usage during descent is 25% for about 30 minutes (1,250 kWh). To have a three hour flight (plus 45 minutes of reserves per FAA FAR 121), you’d need about 18,750 kWh of energy, just under our estimated capacity of 19.2 MWh.

Turns out no matter how you run the numbers on any sized airplane, you really only get about 2-3 hours of operating the aircraft, which is bad for aircraft that tend to fly 2-5 hours (think B737 and A320). But, its good for regional jets where the longest flights are only 2-3 hour. It would seem logical to have Regional Jets be the first type of aircraft using batteries for propulsion. In order to have electric aircraft fly longer routes, you’d need to improve engine efficiency (use less kW to generate 1kN in thrust), increase battery weight and volume characteristics (store more energy per unit mass or per unit volume), or figure out a way to put a highly efficient generator on the plane along with a fuel source (e.g. a 5MW turbine and natural gas to provide power during take-off and in case of emergencies).

There are other side effects to running an aircraft on electricity – you’ll end up redesigning the aircraft since you can ditch the fuel tanks; you’ll be flying slower, probably M0.7 instead of M0.78 or M0.8 that current jets fly at, which means that three hour flight wont go as far as it used to; better protection against lightning; more efficient interior use of energy; and more. The ranges from various airport hubs (700mi) show that it’s range wont be a big deal (map from Great Circle Mapper).

ejets

Apple & Cars

So the latest rumor this week is that Apple is going to develop a car. They’re hiring automotive designers and engineers. Yes, it would be totally awesome if Apple came out with a car, and it kicked GM/Ford/Chrysler’s asses the same way the iPhone kicked Microsoft and Blackberry’s asses.

But can Apple fix any of the issues that currently face electric vehicles? Or will they just be a slightly different $100,000 Tesla, splitting the market that is not really that big in the first place?

Batteries

As I’ve discussed before, the batteries in the new iPhones rival the batteries in Tesla’s Model S in some aspects, but fall behind in others. The six critical battery parameters are:

  • Cycle life: number of full battery charge/discharge cycles to 80% of its original capacity
  • Volumetric Energy Density: number of watt-hours of energy the battery can store per unit volume, usually measured in watt-hours per liter (Wh/l)
  • Gravimetric Energy Density: number of watt-hours of energy the battery can store per unit of mass, usually measured in watt-hours per kilogram (Wh/kg)
  • Power: the ability of the battery to generate or accept power, measured using rate-capacity defined as the C-rate – 1C is charging or discharging the battery in one hour, 0.5C is two hours, 2C is 30 minutes, and 10C is 6 minutes
  • Safety: how much torture can the battery withstand before it becomes a danger to the people around it
  • Cost: the price per usable kWh of battery capacity for the vehicle

Assuming the 1,000 cycle life promise Apple made when it went to sealed batteries is still true, that would provide for a long lifetime (for a 200 mile EV, 1,000 cycles to 80% yields about 180,000 miles on the pack before it only gets about 160 miles per charge).

The iPhone 6 and 6 Plus battery’s energy densities are quite good – 250Wh/kg and 575 Wh/l. The battery cells in the Tesla Model S are around 250Wh/kg and 700Wh/l. This means Apple’s equivalent batteries would weight the same, but take up 22% more space – this is a difficult thing to overcome, so Apple would need to be very creative on how they can come up with more space to store the battery pack relative to Tesla’s battery pack.

The power output of the current iPhone batteries is unknown, rate capacity generally isn’t an issue for batteries in small consumer electronics. The iPhone and iPad batteries can usually recharge in about 1 to 2 hours, which indicates a C-rate of 1C. Batteries for EVs generally need a C-rate of 2C to support fast chargings and highway speeds in all conditions (rain, snow, headwinds, etc.).

Apple’s batteries are generally safe. The lithium polymer cells are a lot safer than the NCA chemistry used in the Tesla Model S.

Finally cost, Apple and Tesla produce roughly on the same scale now (see below) but Tesla has a much more aggressive ramp planned for battery production than Apple does. And the lead time on building new battery manufacturing capacity is pretty long.

Quantities, Oh God The Mass Quantities, of Batteries

Next I wanted to figure out how many kWh of batteries Apple sold in 2014. This is pretty difficult because Apple’s phone models have different cell sizes: 5/5S/5C varied between 5.45 and 5.96Wh, the 6 has 6.91Wh, the 6 Plus has 11.1Wh. So beyond that, the mix of how many phones sold is unknown, so thats another estimation we have to factor in.

Lets assume that for the first three quarters of 2014 (no iPhone 6/6 Plus), the average battery size per phone sold was 5.7Wh, and in the final quarter the average battery size was 6.5Wh. In the first three quarters they sold 118M iPhones, and in the insane fourth quarter they sold about 75M iPhones (mix of 5-series and 6-series phones). This results in 672 MWh of batteries sold in the first three quarters and 487 MWh of cells sold in the final quarter, for an iPhone total of 1,159 MWh of cells, or just over a gigawatt-hour of energy storage devices.

The iPad sold 63.35M units. We can judge from the average selling price of around $420, that a lot more iPad minis are being sold than traditional, larger iPads. If we assume that the mix is 4 mini iPads to 1 large iPad (either last gen or current gen), then the average battery capacity was 25Wh, which is a total of 1,583 MWh of batteries.

This brings us to an approximate total of 2.75 GWh of battery cells produced by Apple for just the iPad and iPhone line. This doesn’t include the batteries used in the iPod or in Mac laptops. Estimating the mixes and volumes of laptops and iPods is beyond my expertise at this moment.

Meanwhile, Tesla sold 31,600 or so cars. If the average unit battery capacity was 75kWh (3 85kWh units for every 2 60kWh units sold), that would yield about 2,370 MWh, or 2.37 gigawatt-hours. For comparison, the Gigafactory will be able to produce 35 GWh of batteries.

It is safe to say that Apple uses more batteries than Tesla in 2014. However, that may change in 2015, as Tesla will try to grow their overall production by 70%, increasing their total annual usage to about 4 gigawatt-hours. Apple, with iPad sales flattening or even declining, likely will not see a 45% increase in battery cell usage to keep up with Tesla.

(the logistics and supply chain people at Apple really do the Lord’s work, hats off to them)

Design & Engineering

I have no doubt Apple’s design team would have a field day with an Apple-mobile. I just hope its as practical as it is beautiful. One of the recent thoughts that has caught my attention is that the value in the car itself is changing. Thirty years ago, 0% of the value of a car came from the software. As the cars got better, engine computers became more advanced, and the infotainment systems in cars became more prevalent, the value of software has increased, from 10% to 40% over the next 10 years as cars learn how to drive themselves, manage their internal components, and become more “smart” in general.

This puts companies like Apple and Google ahead of the game, with their fleets of software engineers and development know-how. Ford, GM, and everyone else has to play catch-up. Can they offer sufficient amounts of money and incentives to lure developers away from places like Apple and Google, where they could invent and develop things to change the world, to Ford, where they will make another difficult-to-use in-car infotainment system.

One interesting aspect would be Apple deciding to take advantage of Tesla’s offer to release all their patents. They can use the same skateboard battery module design and powertrain to underpin the car, with a new design and Apple flair to the rest of the car.

Actually Manufacturing the Car

Tesla’s most recent quarterly conference call brought out the bears – they’re burning cash like crazy on capital expenditures in order to ramp up for an annual run rate of 2,000 cars a week (100,000 per year) as well as building the Gigafactory that could make cells for 500,000 cars a year in 2020, plus batteries for renewable energy storage.

However, all this spending – $5 billion on a battery factory and $2B or so more on its factories in California, is just petty cash for Apple. Apple currently has a $177B cash pile, of which $150B is net of debt. Apple could easily invest $5B in the facilities to build the batteries and the cars – its not a matter of whether they have the cash, its if its the right way to spend that money.

More Importantly, Supporting the Car

The genius bar is usually pretty good about customer service (I haven’t been in a while, knock on wood), even if the lines are horribly long. But how does that translate to getting your Apple EV fixed? Most Apple Stores are in malls, not a place you can drive your car into to get fixed. So what does Apple do? If they go with automotive franchises, they lose their exacting control over the process. Beyond that, they run into the same problem as Tesla with franchises – it’ll be multiple brands under one roof since they will be a small-time player to begin with, and its always more profitable for the dealer to sell a higher maintenance gasoline car compared to a low-maintenance Apple EV because dealers make their money on service, not on new car sales.

It would make a lot of sense for Apple to partner with Tesla on the supercharger network, and infuse a boatload of cash to expand it to support the number of Apple EVs made. Here there are a lot of brand synergies between Apple and Tesla.

But What’s the Sustainable Competitive Advantage?

Apple would only be thinking about becoming a car manufacturer (because eventually it will be more than one car – it’ll be a line of cars) unless it thought it could bring something to the table that all the other companies out there (Ford, GM, Toyota) can’t, and that it would have a long term sustainable advantage. They aren’t trying to be like Elon Musk, who just wants to advance EVs and save the planet from carbon poisoning.

Design? Apple has impeccable design under Jony Ive. The Model S has great design, but lacks luxury in many ways that show its newness to the car industry (the seats, the small visor), and those are being fixed, but it will take a while. Apple will likely have some of these issues out of the gate too, but they would likely be fixed within the first few iterations.

Batteries? Could Apple be working on engineering and developing its own batteries? Not likely. As I illustrated above, Apple ships a tremendous amount of batteries every year. Is it enough to rely on the battery industry at large to continue to innovate in the battery space? Maybe not, but battery research is remarkably difficult – the annual improvement rate is only 7-8% and big breakthroughs are very rare, even if the scientific papers stack up to the ceiling. If Apple has something up it sleve to differentiate itself like working, mass-producible solid-state batteries that offer 700Wh/kg and 1300Wh/l, it would be a coup in the portable consumer electronics and EV worlds – phones as thin as 15 playing cards, cars that can go 400 miles without recharging. But this is very unlikely (I really hope I’m wrong but I doubt it).

Integration? This is always where Apple shines. Apple isn’t generally the first to move (they weren’t first with contactless payments) but they are usually the first to get it right from top to bottom, in a way that the user can understand. The difficulty here is that cars are a mature industry, very mature. Its easy to say that just about every company could do in-car computers better, even Tesla. Apple will show everyone how its done. But after that, and people understand the new paradigms for how people interact with cars, then what? This knowledge and innovation diffuses throughout the industry and becomes general knowledge in the same way physical keyboards went away and capacitive touch screens became the norm.

Self Driving? The individual automakers aren’t doing all the heavy lifting individually, automotive suppliers like Bosch and startups like Mobile Eye are the ones coming up with the hardware and software to solve pieces of the autonomous driving puzzle. Apple could either redo that work or simply integrate parts from suppliers into a self driving system like Tesla is. It’s nothing terribly novel or unique.

Verdict

The problem to be solved with Electric Vehicles is batteries – weight, volume, range, cycle life and safety. All five dimensions need to be improved, plus the cost will need to come down dramatically before the general public adopts EVs over gasoline cars (especially in the current gas price climate).

What isn’t a problem is design or features. Sure, design can be improved and refined, but a better designed car won’t bring out customers in droves. An electric car fits very nicely with Apple’s sustainability goals – working to have a cleaner environment, but there won’t be that much of a market given the current limitations on batteries. This is the problem Fisker had – brilliant design but they didn’t solve the battery problem in a new or novel way – and now they’re out of business.

Its difficult from the outside at this early stage to determine why Apple would want to develop a car, along with the immense investment that would need to accompany development and production if it had honest aspirations of being a worldwide automotive manufacturer. For Apple to enter the market, there needs to be some long-term competitive advantage here. I just don’t see it right now – just designing a better looking or more user friendly EV doesn’t solve the major pain points consumers have right now.

The problems with EVs are battery range, recharging time, and battery weight and volume. And Apple isn’t more or less likely to be the company with a group of electrochemists that discover a breakthrough than any other company, large or small, doing battery research today. It is for primarily that reason that I think Apple would be a fool to enter the automotive space, specifically EVs, in the short term. As cars transform from machery we operate to automated consumer electronics on wheels, there is a space for Apple and others who want to move in that line of products, but that transition is 10-15 years away.

Next Batteries

I decided to pick out four up-and-coming battery companies to highlight the companies that are trying to break in to the battery industry with breakthrough innovations. Keep in mind – they can get all the way to cell commercialization, but to compete in the EV market they will go up against the highly integrated cells Gigafactory Tesla is building on cost, a very tall order.

Li-S

Lithium Sulfur cells have an excellent energy to weight ratio, but have struggled with energy to volume ratio and cycle life. The upside is that Li-S is a relatively safe chemistry, so car companies will be able to reduce the amount of safety equipment integrated into the battery pack, increasing the percentage of pack weight and volume dedicated to battery cells.

Sion Power: Recently broke a record for longest unmanned aerial flight of an all-electric UAV (14 days) using solar power and their 350Wh/kg batteries to store energy during the night.

Oxis Energy: Recently announced 300 Wh/kg, in a 25Ah cell. I’m guessing their Wh/l figure is quite low, but they are working on increasing that aspect as well as getting to 400Wh/kg by 2016 and 500Wh/kg by 2018. Their EV cell target is a 95Ah cell with 450Wh/l and 400Wh/kg.

Lithium Solid State

Solid State batteries have been a holy grail for batteries for a while now because they can be form-fitted to fit spaces. They have high volumetric density and cycle life, but have issues with Li-Ion conductivity through the solid electrolyte (low power, slow changing current).

Sakti3: On a recent episode of Autoline, the founder and CEO of the company stated they had achieved over 1,100 Wh/l in a battery cell. No mention of weight of the cell, but she expressed her optimism that they could be in consumer electronics in two years (late 2016).

Solid Energy: Recently demonstrated a cell with 1,337 Wh/l. Expresses confidence that they will be commercially available in 2016.

Apple WATCH battery math update

One the things I mentioned during my Apple WATCH post was the estimated battery capacities. Well, thanks to iFixit, the iPhone’s battery characteristics have been revealed and using the same type of batteries in the WATCH would stand to improve on my estimates somewhat. Here are the figures for the iPhone 6 and 6 Plus batteries

So what does this mean for the watch? That the battery capacity would be slightly higher than my original estimates of 1.9Wh or 520 mAh at 3.6V. Its more likely that the battery will end up around 600 mAh or 2.1Wh at 575Wh/L.

Tesla Model S AWD, Autopilot and Model 3…

Model S AWD

The Model S AWD models are impressive. We knew they were coming for a while now – there is a space in the frunk that would be perfect housing for the motor for the front wheels. The performance is the headline here – 691 HP (combined) and 3.2 seconds for the 0-60 time launches the Model S AWD into supercar territory. But its not a supercar that just sits in the garage and looks nice – its a great daily driver, highly efficient, very low total cost of ownership per mile relatively speaking, and very user friendly. Beyond that, the way the two electric motors are tuned to work together help improve the overall efficiency of the car, allowing it to, despite the added weight of a second motor, increase the electric range from 265 to 275 miles for the performance model and a whopping 30 mile increase from 265 to 295 for the non-performance 85kWh model (numbers provided are Tesla estimates, EPA numbers are presuming to be pending certification before deliveries in December).

Autopilot

The new Autopilot functionality of the Model S seems eminently more practical than the hyped up Google self-driving car of the last few years. The great news is that instead of having to wait until 2018 or 2020, we can get highway autopilot several years earlier than expected.

The sensors include sonar around the car (forming a bubble around the car) as well as a forward-looking radar and camera system. These allow for active safety systems – automatically braking the car if an obstacle in front is detected, preventing you from steering into a car in your blind spot, etc. These features have existed in cars for a few years now. Beyond the active safety systems is the new Autopilot software.

Autopilot is a very fitting name for this feature, as it mimics overall idea of autopilot on a airliner – the pilots control everything until the plane is at a comfortable cruising altitude and can be turned over to an automated system. Same with cars – if your commute is a long drive on a highway, once you’re on the highway, you can manage the car with just the turn signal. Cameras read the speed limit signs, slow for cars in front of you, and perform actions to keep you safe.

Though after watching the official Tesla video and reading the press release, I wasn’t quite sure what features are being delivered today and what will be made available in future over-the-air updates to the autopilot software. What’s important is that the hardware necessary for autopilot is being delivered today. Software improvements can come in time, but its prohibitively expensive to go back and retrofit this hardware on existing cars (Tesla has stated they won’t retrofit, so you’d have to buy a new Tesla and trade in your old one). As Tesla adds features to the autopilot software over time (the ability of the car to park itself in a garage without you in it), the car will evolve to the self-driving ideal, though it won’t make it all the way there.

The only negative is I don’t think there are enough sensors – that in the future, rear facing radar sensors or cameras will be added to the package to help the car switch lanes when there are high differences in the rate of speed between the two lanes. And making sure the sensors are redundant enough to withstand a failure.

Model 3

One of the interesthing things about the new AWD cars is that the smaller electric motors (188 and 221 HP) seem to be a perfect fit for a Model 3-sized car – one for the standard model, and one for a “performance” Model 3. Tesla should be able to re-use the motors with small adjustments in the firmware to optimize it for single-axle drive.

Beyond this, we’re able to get a better idea of the specs of the Model 3. One thing Elon has stated is that the Model 3 will be about 80% of the size and weight of the Model S. The Model S originally (2012) had a curb weight of 4,450 lbs. However recent statements have indicated they’ve taken “hundreds” of pounds out of the car, I’d estimate the current curb weight for the single-motor model is around 4,200 lbs. A 20% reduction would put the car around 3,400 lbs. A 188 HP motor should be able to propel the car with respectable (certainly not supercar) 0-60 MPH times. By comparison, my Chevy Volt has a curb weight of 3,700 lbs and only a 160 HP motor. While 188 HP might not sound like a lot, the fact that its electric and instant torque will compensate for the relatively small HP rating compared to gasoline engines.

The battery for the future Model S will end up around 45kWh using these smaller motors, reduced vehicle weight and improved efficiencies (an improvement from 300 Wh/mile in a RWD Model S to 225 Wh/mi for the base Model 3). This reduction in pack capacity, combined with the reduced costs of the pack through the Gigafactory increase the chances that Tesla will be able to hit the $35,000 price with a base 200-mile model. The conservative estimate for packs out of the Gigafactory is $196/kWh (down 30% from Tesla’s early 2014 baseline of around $280/kWh), and the aggressive estimate is around $168/kWh (down 40%), which would put the pack price between $7,600 and $8,800. This is 22-25% of the price tag of the overall vehicle, which should leave plenty of room for the rest of the car (50%, or $17,500) and a gross margin of 25%. A longer range 60kWh version could be made available with the beefier 221 HP motor for a range of just over 250 miles. The only issue with a battery pack that small is how fast (or slow) it can be supercharged.

The Apple Watch & Batteries

One of the things not mentioned at today’s Apple Keynote was the battery life of the APPLE WATCH. It was implied that it would be recharged every night, there was nothing specific about the hardware itself.

Battery life is determined by three things – size of battery, power intensity of the CPU/SOC and the power consumption of the display.

We will assume the display is using the most efficient display possible – IGZO or aSi. This will minimize the power draw from the display as much as possible.

The CPU/SOC is likely minimized as much as it can for the first generation product. This is where Apple will need to innovate – integrating more and more functions from discrete chips in the APPLE WATCH package into one piece of silicon that can be fabricated at a small process (which as of right now is 20nm from TSMC).

Batteries, however, don’t progress as quickly as everything else. They improve at about 8% per year, and thats in a good year. It’s why we’re not all driving electric cars right now. Electrochemistry is difficult.

Specifically, the issue with the batteries for the APPLE WATCH is the volumetric energy density. Apple needs a battery that has a high volumetric energy density (measured in Wh per liter) so that they can cram as much watt-hours as they can inside a specific volume. This is different that EV companies, which are typically looking for high gravimetric energy density (Wh per kg).

Right now, some of the best batteries are about 700 Wh/l (for this application, NCM Li-Polymer from SK Innovation at 200Wh/kg and ~700Wh/l). If we assume the battery inside the WATCH is 30mm x 25mm x 5mm, or 3750 cubic millimeters, thats 0.00375 liters. If Apple used the best battery technology possible, they would have about 2.7Wh of storage (730mAh at 3.6V). That figure seems high, so I’m guessing they’re using something less substantial (probably in the 500 Wh/l range) around 1.9Wh, or 520mAh. 

The difficulty Apple faces when it comes to battery development is that it is largely on its own – most battery companies are working hard to increase the gravimetric energy density and the cycle life of batteries. For example. Li-S batteries, while the gravimetric energy density may increase to from 200 to 400Wh/kg, the volumetric energy density is only in the range of 425Wh/l. Lighter batteries do Apple no good – they need more space-efficient batteries.

This is why my hopes are dim for amazing battery life on the APPLE WATCH anytime soon. It will take several generations of hardware integration and software optimization before the product matures. But this is no different than the original iPhone, with its slow 2G data speeds, adequate battery life and no apps.

Cheaper – not better – batteries will rule the EV market

In 2010, Panasonic announced they had developed a 4.0Ah silicon anode battery that would go into production before the end of March 2013. At the end of 2013 the battery is nowhere to be found.

It’s easy to chalk this up to product development delays. I don’t doubt this is hard work – science is hard. If it were easy we’d have fusion and flying cars by now.

Rather, I think that for large battery manufacturers like Panasonic and LG, they’ve redeployed resources from making better batteries at the same price, to making their existing batteries cost less. Reducing the cost per kWh of battery capacity is now job one. The disruptive threat from some start-up coming out with a novel process to make a 4x energy capacity battery is mitigated by the fact that the large mainstream suppliers will be able to undercut them on both price and manufacturing capacity. Their novel process might work for niche applications in low volumes, but it won’t matter much because the cells will, by comparison, be in short supply and too expensive for a mainstream EV.

The change in priorities wouldn’t be a surprising one, given the principle issue with EVs today – cost. If you don’t bring down the cost of the battery packs in the EVs today, there won’t be broad-based demand for EVs tomorrow no matter what the range of the vehicle is. When EVs take the place of a second or third car in a household, the range issue isn’t nearly the problem it is made out to be. And the market for second and third cars in households that can afford suburban homes to recharge them in is sufficiently large this early in the electric vehicle adoption curve.

Battery costs are not generally published, but we can estimate that as of mid 2013 are around $350 per kWh at the finished pack level. This makes the price around $30,000 for the Tesla 85kWh battery, $5800 for the Volt, and $8500 for the Nissan Leaf pack. By the end of 2015, prices could be around $250 per kWh, and $150 per kWh by the end of 2017. At the second long term price goal of $150, it becomes possible to sell a 60 kWh/220 mile range EV for $35,000 because the pack is only $9,000 (or 30% of the bill of materials), roughly in line with the Nissan Leaf. As Tesla has shown, a purpose-built EV can accommodate the amount of cells necessary for this battery pack size. Existing battery technologies (NMC, LiFePO4) will continue to improve marginally each year, providing more energy capacity per unit volume and per unit weight.

Once the price issue is resolved, battery makers can focus exclusively on incorporating new technologies to make EV range no longer an issue without spiking the price. While emerging technologies like lithium-air technologies may become practical after 2020, when the cost can come down enough to put them in affordable EVs for the driving public is the larger question.

OXIS Energy to scale up production of Li-S batteries in 2014

OXIS Energy is planning on commercial production of their Lithium Sulfur batteries in 2014. The cells are expected to be around 200Wh/kg (low for Li-S but its still early) and achieve a little more than 1500 cycles to 80% capacity. They have been tested to be very safe (a nail puncture test resulted in a 1.4C rise in temperature and no expansion or pouch rupture).

These batteries are suited well for EVs and marginally for EREVs.

For EVs, the energy density is about double of what was in first generation EVs (Nissan Leaf). This means that replacing the pack with the new cells would provide almost double the range, from 75 miles to 130-150 miles. The cycle life of 1,500 cycles would provide for about 195,000-200,000 miles to 80% capacity (a nominal range of 104-120 miles). This would be a big boost for EVs.

For EREVs, the weight and size of the pack could be reduced by 1/2 over the 2010 baseline with the same electric range, or by 1/3 to achieve a 25-30% range increase. For something like the Volt, this would mean a return of the 5th seat and a boost in electric range from 38 miles to about 45 miles in a 19kWh pack using 13kWh of energy. Because cycle life is non-linear in Lithium batteries (well, it is for Li-Ion, I’m assuming that it is also that way for Li-S), by using only 70% of the battery we extend the cycle life by almost 60%, increasing the cycle life from 1500 to 2400 to 80%, which would be good for 108,000 electric miles – just barely exceeding the 8-year, 100,000 mile warranty supplied by auto manufacturers on EREVs and EVs (notwithstanding any gas-powered miles that also count under the warranty). This just-clearing-the-hurdle approach however doesn’t leave a lot of margin for environmental factors (heat, cold) and time-based degradation of the cells. Cycle life would need to be extended more (from 1500 to 2000 cycles), or cell energy density would need to be improved (more miles per battery cycle) to remedy this.

Ultimately, the biggest issue facing OXIS Energy isn’t the performance of the cell in 2014, rather what is promised by other companies for 2015 and 2016 – 300 and 400Wh/kg energy densities that will revolutionize EVs. If they can keep their Li-S chemistry competitive (and outrun Li-Ion in the mid- and long-term race), or if their competitors fail to deliver on their promises, they will be successful.

Battery Technology Forecast

So I’ve been reading more and more research on batteries lately and I’ve come up with what I think are some reasonable estimates on the different types of technologies and when we’ll see them and what they mean.

(sorry for the poor formatting of the table, this WP theme is really narrow)

Technology Energy Density (Wh/kg) Power Density (W/kg) First Production First in Cars Implications
First-Gen Tech 100-125 900 2008 2010 These are the batteries the Volt & Leaf launched with. Some more recent EVs have slightly better tech (Teslas, new Fords, RAV4 EV, etc)
Silicon Anodes 200-300 1500 2013 2014 The first significant boost to Li-Ion batteries since the electrification of the vehicle started in 2010. EV range will increase to about 125-150 miles, from 75 today.
Layered Manganese Cathode 400-500 1200 2015 2017 The second major boost, this will push EVs to 200 miles of range. Prices come down enough that two car households will now start buying an EV to replace one of their gasoline cars.
Lithium-Sulfur 600-750 2000 2018 2020 EV range increases to almost 300 miles, enough to alleviate range anxiety for most drivers. Fast-charge systems between cities are robust enough to support long distance driving east of the Mississippi and along the west coast.
Lithium Air 1000 500 2020 2022 The low power density relegates this technology to grid backup at first, but after a while is improved to work in pure EVs (wont work in plug-in models). 400-500 mile range EVs become common with this technology.

Don’t hold me to this, no one can really predict the future. This is all based on how I see things going. The next 18 months or so will tell – can companies start to deliver on their promises of silicon anode batteries that have good enough cycle life for use in an electric car. If they can then we start to see larger gains in battery tech – instead of an 8-10% gain in energy density per year, we see closer to 20% per year.