23Sep 2014

I love my electric vehicle, or EV, as we affectionately call our electric cars here in California. I love that it is quiet. I love its fast pickup from a stop. I love that it requires practically zero service: no oil change; no transmission service; no timing belts. Of course, I love too that it is eco-friendly and driving in the carpool lane. I am bullish on the future of electric vehicles, but first, the technology has to evolve a little more to give the consumer less anxiety, the topic of today’s writing.

No, it is not a Tesla. It is not a Leaf. I am one of the early adopters of a Ford Focus Electric. It looks like a regular Ford Focus so it does not stand out in traffic. I nominally get about 80 miles of range which includes a lot of freeway driving…my normal daily commute. Slower driving in stop-and-go traffic increases my range to about 100 miles. Shave 10 or 15 miles during our mild California winters.

My vehicle is powered by a 24 kWh lithium-ion battery pack that is manufactured by LG Chemical, but in reality, only about 19 or 20 kWh are available to me. That’s because to provide a 100,000-mile warranty, the battery has to reach 100,000 divided by 80 miles = 1,250 cycles minimum. So battery manufacturers and car makers choose to reduce the capacity of the battery to gain cycle life. Remember the whack-a-mole strategy from earlier posts. Using the water analogy, if you don’t fill up the water bucket to the top, you can fill it more times over its life. Tesla Motors, Leaf and virtually every car maker employs this strategy. For the time being, it’s ok, but that has to be addressed over time in order to make electric cars more affordable for the broad population.

When I first bought my car, my range anxiety was high. The car dashboard displayed how many miles of driving I had available in the tank, ehem, battery. I charged my car overnight, and I started my morning with about 80 miles. By the time I got to work, the dashboard showed less than 60 miles.  I was nervous every time my dashboard dropped below 50 miles, so I charged as frequently as I could. That’s range anxiety. 

Now, nearly a year and half later, my behavior has changed drastically. I drive my car down to 10 or even 5 miles left in the battery. I plan my route. I know my destination and I know my return route. Keeping 50 or more miles for insurance does not make any more sense. I became comfortable with the given range of 80 miles and I use it effectively. I consistently get about 80 miles, and in the time since I bought it, my comfort level increased and my trust in my dashboard’s range estimate has increased. Of course, my maximum driving range was still limited to the greater Bay Area. I cannot drive my car to, say, Los Angeles, but I do use nearly every mile available to me in battery.

However, my range anxiety got replaced with something else: Charging anxiety. You see, if I am comfortable taking my battery down to nearly zero, I need to know that I am close to a charging outlet when I stop. Good news here! The San Francisco Bay Area has lots of charging outlets. But the problem is the speed of charging. If my battery is near zero, it takes a whopping 20 hours to charge it at 120-Volt, and a mere 4 to 5 hours using the 240-Volt chargers. Ouch! That is not acceptable. That is at the core of anxiety in battery-powered cars, phones, or anything else. We need to charge them fast, and I mean really fast….As fast as filling up your gas tank at the gas station. 

If you look at what Tesla Motors is doing and what Elon Musk keeps advertising, none of it is about extending the range of their cars. Their publicized priorities are about building cars for the masses (in other words, lower price point) and secondly about charging their cars fast, in half an hour or so.  

Fast charging…we need it. Remember that!

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22Sep 2014

I talked about capacity, cycle life, tricks of the industry….today, I will distill it down to some simple thoughts for you to keep in mind when you are ready to select your next mobile device or smartphone. In particular, today’s writing is about selecting a device with the proper battery capacity that can last you an honest day.

Mobile device manufacturers will give you an estimate of the battery life for their devices. For example, Apple’s tech specs say that the battery on the iPhone 6 will give you up to 14 hours of talk time on 3G. Samsung’s web page says that the Galaxy S5 will last up to 12 hours of internet use time on 4G. Plenty of independent sites on the web try to give a more objective analysis of the actual time a consumer can expect of their new device. Anandtech, for example, does their own thorough battery testing and provide a comparison of the battery performance of different devices. GSM Arena assigns a battery “Endurance rating.” Think of it as an index meant to give you the user an understanding of the battery’s ability to last.

Yet, the landscape remains confusing. What do the numbers mean in real life? Why is it that so many users can’t reliably get a full day of use when these sites clearly claim a full day of use. Generally, predicting battery life has been difficult for the industry because the usage patterns of consumers vary wildly across the board. An employee with a desk job who uses their smartphone for limited personal use will see a very different performance relative to a traveling executive or salesperson who is constantly using their device.

Early cell phones had far smaller battery capacities (only about 600 or 700 mAh), yet they lasted an entire week if not longer. But these devices did not have too many features…only a radio transmitter-receiver to make phone calls. Today’s mobile devices have multiple radios for the different frequencies and bands (2G, 3G, 4G, LTE…); they have beautiful but power-hogging displays with increasing resolution (meaning more power); they have GPS and navigation components that also need power from the battery; and worst of all, we, you, and all of us users, want to use them constantly in the day as we check emails, write texts and SMS messages, and check our favorite apps that want to access radio, displays, GPS, all simultaneously.

It is no surprise that the battery capacity in smartphones has grown massively since the introduction of the first iPhone to accommodate this extra demand for electrical power. From a battery capacity of about 900 mAh in 2007, most smartphones today have a battery capacity ranging between 2,500 mAh and 3,000 mAh for Android phones. iPhone 6 uses 1,810 mAh and its larger brother, the iPhone 6 Plus, packs more than 2,900 mAh of capacity.

For the most part, as experience and feedback from users have shown so far, smartphones with batteries closer to 3,000 mAh in capacity seem to provide their users with an honest full day of use (or more), even heavy users seem satisfied. So if you are shopping for a new smartphone, try to shoot for 3,000 mAh unless you know you are only a casual and occasional user in which case, about 1,800 to 2,000 mAh will likely be sufficient. Don’t get too fooled by the marketing gimmicks.

So why can’t we get smartphones with 4,000 mAh or even higher capacity? Trying to fit more than 3,000 mAh in a standard 5-in screen device is very difficult. Remember yesterday’s writing and the whack-a-mole problem…if battery manufacturers increase the capacity, they will take a hit in cycle life or charge times. It is getting quite uncomfortable for them. So for the foreseeable future, expect smartphones to have batteries in the neighborhood of 3,000 mAh, but not much more than that, unless of course you are in the market for a huge 6-in phablet.

Tablets have it a little easier. They have a larger form factor and therefore can carry a larger battery — 6,000 mAh up to 10,000 mAh. Most tablets on the market have a decent battery use time.

But wait, there is another problem. What if you forget to charge your smartphone’s battery overnight? You wake up in the morning and realize your battery is down to 20% or less, and you need to run out the door to the office, school, or take your children to their school…As batteries have grown larger in size and the anxiety about getting a full day of use has dwindled, we are now beginning to face another problem, one of how long does it take to recharge the battery — or refilling the tank.

If we use the car as an analogy, most vehicles manufactured today have a range between 300 and 400 miles (500 to 650 km). We, as a global society, seem to be content with that range. We don’t complain to General Motors, Ford, Toyota, Mercedes, and the other car makers about the “limited range.” That’s because we know, implicitly, that if the tank is low on fuel, we are very often within reach of a refill station and, most importantly, we can refill our tank in a matter of minutes. This is the use model that mobile devices have to reach soon. We will soon expect our devices to last a full day of use, but also expect that our devices can be recharged substantially faster.

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21Sep 2014

Several years back, as we were doing our initial fundraising round for Qnovo, lithium-ion batteries were the craze! A123 had just gone public at an insane valuation. Gas prices were through the roof and GM announced the all-exciting electric Chevy Volt. Tesla Motors had their Roadster and was promising the then new Model S. Promises of innovations that can make electric vehicles part of the mainstream were abound. Apple introduced the iPhone which for the first time in history had an embedded battery (one where the user could not remove). These were exciting times! With this background, you can then appreciate our surprise when one investor with ample experience in this space uttered a deep skepticism of the battery ecosystem. There seem to have been plenty of broken promises and certainly, as I learned later, opaque specifications that seemed difficult to verify. “There were liars, damned liars and battery suppliers,” continues to resonate in my head, and after several years, seems to be more often true than not.

This blog is not meant to bash battery manufacturers. They do provide an immensely useful product and underlying technology that has proved very central to a mobile society. Not many of you remember the first mobile phones (not even smartphones) some 15 or 20 years ago when the battery, back then made of NiCd or NiMH, was the size of a brick….and it lasted too little. Rather, I want to use this blog to clarify who are the main manufacturers and what challenges they are facing.

There are over 6 billion lithium-ion batteries that are manufactured every year. Big numbers! Mobile devices account for nearly 75% of this volume. The rest go into electric vehicle and bicycles, camcorders, cameras and other items such as power tools. Less than 10 companies account for this worldwide volume. They tend to be large chemical conglomerates based in South Korea, Japan and China. Samsung SDI and LG Chemical are based in South Korea and are subsidiaries of Samsung and LG, respectively. In Japan, Panasonic, Sony Energy and Hitachi Maxell are the prominent ones. Panasonic is well known as the primary supplier of batteries to Tesla Motors. Then there are a number of fast-growing manufacturers out of China, primarily, Lishen, ATL, BAK and BYD. Lithium-ion batteries made in China tend to be of lower quality. They are widely used in China but mobile device manufacturers outside of China have generally preferred to use batteries manufactured by South Korean or Japanese companies. 

The US has a few small battery manufacturers that tend to be specialized, say for medical or aerospace applications. There are also several innovative and promising startup companies in the US that are pushing the envelope in terms of new materials, new designs and cost-effective ways to build batteries. 

Battery manufacturers face a slew of challenges, both technical and economical. First and foremost, batteries including lithium-ion batteries tend to be inexpensive. A battery in a typical smartphone costs in the neighborhood of $1 to $2. Profit margins in batteries tend to be very thin. Battery manufacturing is a very capital-intensive business. Safety concerns also plagued the industry in the past decade. Yet, it is a very competitive space, and the new Chinese manufacturers are only adding  increasing economic pressure on the established players.

Technically, the primary challenge is that battery manufacturers are not keeping up with the insatiable demand by the mobile and electronics industries. We hear of Moore’s Law in electronics; it is driving the mobile industry. Moore’s Law is the observation made by Gordon Moore at Intel in 1965 that electronics double in capacity every approximately 2 years. In contrast, batteries have doubled in capacity every 15 years!  This is a serious gap and growing problem.

Additionally, there is immense knowledge around electronics. High-tech companies have great talent around designing and manufacturing electronics with superb quality. In contrast, battery talent is limited. Companies that build mobile devices also have a great ability to understand electronic components and designs, yet surprisingly, many of them fall far behind in their knowledge of batteries. The result is that batteries and their specifications tend to be an obscure topic, and innovation in general has lagged. And to make matters worse, electronic and software engineers, the backbone of the mobile industry, simply don’t like to deal with chemistry!

That is changing, gradually. It has to change. Batteries, their manufactures and the entire ecosystem needs to catch up to the operating standards and levels of innovation that the electronics and mobile industries have set forth.

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20Sep 2014

Damage in a battery happens. You can’t stop it. It’s part of the physics. Yes, it is possible to mitigate it. It is possible to postpone its onset. It is possible to reduce its impact (that’s part of what our company Qnovo does)… But it’s always there and we need to deal with it. Battery manufacturers have tended to sweep this issue under the rug but it is now coming back to bite them hard.

In technical terms, this damage inside the battery is referred to in terms of “cycle life.” It is essentially a measure of how many times the battery can be charged and discharged before it is deemed dead. As I mentioned in the previous post, a battery is deemed dead when its maximum capacity reaches 80% of its original capacity as a fresh battery. So say a fresh battery has a maximum capacity of 2,500 mAh on its first day of use. After some number of charges and discharges, the internal damage reduces this maximum capacity. Eventually, this figure reaches 80% x 2,500 mAh = 2,000 mAh at which point it is officially deemed to be “dead”, i.e., it needs to be replaced.

Why 80%? and not 75% or 63.1849%? Because experience has shown that shortly past the 80%-mark, the damage accelerates rapidly and the battery capacity plummets very quickly. Not good!

But now you are saying, “how can I know?” Well, welcome to the world of opacity in how battery makers specify their products. As a consumer, you don’t know, nor you can measure it easily. Device makers tell you trust me, but you should not! All these apps that you can download from the Apple or Google stores also don’t tell you anything. Right now, sadly, the only way you can tell that your battery is dead or dying is because it feels that it is dying. Your battery can’t last you the day when only a few months earlier it did. Now to be sure, you also have to make sure that you don’t have one or more rogue apps draining the battery in the background. So if you reset or even restore your mobile device and its battery is still not delivering, then it is a fairly strong hint that something is very wrong with the battery. If you are asking “why can’t you fix it,” the answer is “we can and we are.” Let your mobile device manufacturer know that you are not happy if you suspect your battery cycle life is compromised.

Let’s get back to cycle life. As you can see, cycle life and battery capacity are very closely tied together. Capacity is effectively the capacity that you get on your first day of operation, and cycle life is a measure of longevity of your battery’s capacity. Cycle life is almost like the “Expiration Date” printed on a gallon of milk at the grocery store; except imagine that grocery stores decided one day to simply eliminate printing this crucial date. Grocery stores don’t dare do it! Well, many mobile device manufacturers choose to hide or not disclose the cycle life — effectively this expiration date of the battery is hidden. We are working on changing this behavior. But for now, I will give you some hints and tips on how to deal with this.

Most mobile devices including smartphones and tablets are rated to 500 cycles, i.e., you, the consumer, can expect to have 500 consecutive full charges and full discharges before your battery is deemed dead. Some devices do better than others. For example, older Apple iPhones lasted more than 500 cycles, whereas others either made 500 or fell shy of that figure. 

But some carriers (or operators are they are called outside the US), and in particular, Verizon Wireless, began demanding that mobile device manufacturers increase their cycle life specifications to 800 or more cycles, to effectively cover a 2-year warranty on the device. This new specification is beginning to proliferate but battery manufacturers are not happy! Increasing cycle life performance is not easy for them, and guess what, most of them are based in Asia and they don’t like to ask for help!

So one of the tricks that manufacturers do to increase cycle life is to — hold on to your seat — increase charge times! Ouch! Now, you are becoming increasing familiar with the battery whack-a-mole strategy that battery manufacturers follow. You want more capacity, well, you may get worse cycle life…you want better cycle life, well, you will get worse charge times….and so on.

Fortunately, the technology to fix this whack-a-mole problem already exists…mobile device manufacturers have to deploy it more universally. For now, here are some hints — albeit a little inconvenient — that you can apply to extend the cycle life of your life battery:

  • Charge your device slowly using the USB port on your PC or notebook, not wall charger or AC adapter. This effectively limits the charging current to 500 mA. Yes, it is slow, but if you are not in a rush, it will help your battery.
  • Charge at room temperature! Not on your car dashboard in the middle of a hot sunny day, or worse yet, in the middle of a cold winter. Batteries hate being charged at temperature extremes, especially below 60 °F (or 15 °C), and above 95 °F (or 35 °C).
  • If you are not traveling or need your phone fully charged all day, then charge your battery to about 80 or 85% — not to 100%. This will also help being gentle on the battery. 

More later.

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19Sep 2014

Yes, I did. That’s when you wake up a few months after you make a proud investment in a new mobile device, then you realize that the battery is not lasting as long as you wanted.

Well, first to be safe, you have to make sure that you don’t have too many apps running in the background draining the battery without your knowledge or your permission. But assuming that you already reset your phone, deleted the useless applications, and turned off all the background app refreshing, and you are still not getting the battery life that you had only a few weeks or months ago, then you are right, you are now experiencing the signs of battery damage, or in geek terms, it’s called “capacity fade.”

Remember when we talked earlier about the charge capacity of a battery and said it is measured in units of mAh. So let’s say that you battery is rated at 2,500 mAh. So when your device is fully charged, and your fuel gauge in the upper right hand corner of your screen is reading 100%, it means that your battery is holding about 2,500 mAh of electrical charge…using the earlier analogy of the water bucket, it means the bucket is full and is holding some number of gallons of water.

But this assumes that the battery is new. As damage sets in the battery, its maximum capacity will actually degrade over time and use. This can happen for many reasons, such as poor manufacturing, extended exposure to low or high temperatures…etc. (we will get back to this at a later time). So the battery you have now has a maximum capacity of say 2,200 mAh instead of 2,500 mAh. In other words, you will notice a decrease in your battery life by about 1 to 2 hours per day.  

So now you are frowning, and possibly complaining: “But, but, but….the fuel gauge is still reading 100% when it is full.” Yes, the fuel gauge only reads the available charge in the battery as a fraction of the maximum available capacity in the battery (it’s a mouthful). In other words, on day one, your battery was able of holding 2,500 mAh, so 100% of the fuel gauge is then equal to 2,500 mAh. But after 6 months of use, the battery can only hold 2,200 mAh, and the 100% displayed by the fuel gauge is now equal to only 2,200 mAh. Ouch! 

If you are thinking about where you can read the lower battery capacity of 2,200 mAh, the answer is nowhere. You can’t. The smartphone manufacturer and battery vendors either can’t tell you or don’t want to tell you. This is called “state of health” of the battery. 

When the battery capacity drops to 80% of its original capacity — in our example here, it is 80% x 2,500 mAh = 2,000 mAh — the battery is deemed dead and must be replaced. But as you gathered, it has been difficult if not nearly impossible for customers and consumers to prove that they have a dead battery. 

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