Twenty-five years ago Sony introduced the lithium ion rechargeable battery to the market. (Lithium batteries were originally proposed by British chemist M Stanley Whittingham, while working for Exxon in the 1970s.) In the quarter century since, sales of lithium ion have grown rapidly along with its benefits in comparison with all the earlier rechargeable battery systems. Today, most wireless electronic devices are powered by Li-ion batteries.
The present day market for Li-ion batteries is far more complicated than the original market for small electronic devices and portable computers. Many additional markets have been opened for small devices such as toys, lighting (LCD and fluorescent lights), and medical devices. A slightly different type of Li-ion battery, with much bigger capacity, is being used to power electric vehicles (EVs).
Laptop computers, smartphones, and tablets have become an integral part of our daily lives and, despite significant advances in power saving technologies, their batteries require constant attention or we are suddenly left without our extended brains.
One of the most frustrating things for mobile device users is running out of battery. And one of the most dreaded routines is to be constantly charging several computing devices, some of them overnight and some several times during the day.
The good news is that packing bigger battery power in mobile devices is getting easier, lighter, and cheaper. Soon we’ll be able to have either slimmer, lighter devices with the same amount of battery capacity, or much more reserve energy to power our device longer between charges.
Since the original 1991 product, Li-ion battery energy density has grown by three to four percent every year, resulting in an approx. 2.5x overall increase in energy density over the past 25 years. In 2014 commercial batteries from Amprius, using a silicon anode, reached 650 Wh/L, a 20% increase over the previous technology.
Battery prices have also been falling rapidly. More efficient manufacturing, a much bigger market, and higher density, plus the new market for electric vehicles and energy storage, have helped to reduce the price per kWh to a fraction of what it was 25 years ago. In the past seven years, according to a recent report of the International Energy Agency, the cost per kWh has dropped from over $900 to less than $300. Some vendors such as Tesla and GM report that they have been purchasing Li-ion batteries for their vehicles at $150/kWh.
This new scenario is a blessing for the supply chain of Li-ion batteries for computing devices. New smartphones, tablets, and laptops, will provide faster processing while getting slimmer and lighter.
For example, the 2010 13” Apple Macbook Pro, contained a 63.5-watt-hour Li-ion battery, and weighed 4.5 pounds (2.02kg). Last year’s model is one centimeter slimmer, weighs just three pounds and packs a 49.2-watt-hour lithium-polymer battery, providing the same 10-hour wireless autonomy on a 300% faster computer.
Higher density, however, creates other problems, especially heat and risk of explosion. Last year’s problems with the Samsung Note 7 smartphone showed how difficult it could be to run a high-density battery in a small device. The large phablet used a 3500 mAh battery (13.4 Wh), packet into a slim 0.31 device. Samsung was unable to solve the problem and the Note 7 was finally discontinued. The new Samsung Galaxy S8+ packs the same battery capacity in a similarly slim, although larger, device and so far it hasn’t caused any problems.
It will be impossible to predict how much further Li-ion batteries can be shrunk and how much cheaper they can get. It’s certain, though, that Li-ion battery technology is going to continue powering our wireless units, as well as the billions of Internet of Things (IoT) connected devices, that provide ubiquitous connectivity.