If there is one thing to know about the pace of progress for battery innovation, it’s this: There is no Moore’s law for batteries. The rapid progress that has been made over the past decade in silicon and computing, thanks to the number of transistors on a chip’s doubling roughly every two years, makes the pace of innovation in batteries, in comparison, look like a statue perched in the Louvre. A battery exec once told me that while Moore’s law has delivered 10,000 times improvement over the years for chips, batteries have shown only 3 to 4 times improvement.
However, that doesn’t mean that researchers and corporations aren’t trying — hard. There are hundreds of startups, massive battery conglomerates and university labs that are trying to push the battery envelope and create as much power at the lowest cost for these little energy storage devices.
These battery innovations come in a variety of forms: identifying new mixes of chemicals and metals that can produce long-lasting batteries; using nanotechnology to boost energy density; and developing power management software to extend current battery technology. Whatever the development is, battery innovation will be increasingly important as more and more battery-powered cell phones and gadgets are sold throughout the world (welcome, Chinese middle class) and battery-powered electric cars start to gain more acceptance in certain regions. The Obama administration is trying to get 1 million electric cars on the roads by 2020.
Here are some of the trends and technologies that have been showing the most promise for batteries, as well as what you can expect from the next generation of batteries down the road.
A better electrolyte
Going back to Batteries 101, the electrolyte is the part of the battery that shuttles ions back and forth between the cathode and the anode to charge and discharge the battery cell. In traditional lithium-ion batteries (the kind found in your laptop and phone) this is made of liquid or slurry, commonly a lithium salt in an organic solvent. Because the electrolyte is liquid, it can potentially be flammable (go Google battery’s blowing up), and it also loses capacity under prolonged exposures to high temperatures.
Some researchers are working on different types of solid-state batteries, like using a dry polymer instead of a liquid for the electrolyte. Seeo is a startup out of Lawrence Berkeley National Laboratory that has already started producing a pilot line of its lithium-polymer batteries that the company thinks could double the life of an electric car battery.
Daniel Abraham, a scientist at Argonne National Laboratory, told us earlier this year that a variety of researchers are working on additives for liquid electrolytes that could function like vitamins do in our diet, enabling batteries to perform better and live longer by reducing harmful reactions between the electrodes and electrolytes. An example of this is what Leyden Energy is doing: It says its salt mixture in a liquid electrolyte has created a high-temperature-tolerant and longer-lasting battery.
Sakti3, a startup based in Michigan, is developing battery cells with a solid-state electrolyte that it says could double the energy density of a battery compared with existing lithium-ion batteries. The company is backed by Khosla Ventures, General Motors and Japanese conglomerate Itochu.
Next-gen lithium ion
The lithium-ion battery is the standard used for laptops and electric cars. But researchers are looking to pair lithium with other materials, to make batteries last longer and provide more energy.
One of the more out-there companies is an 11-year-old firm named PolyPlus, which hails out of Lawrence Berkeley Labs. PolyPlus has been working on batteries made of lithium and seawater (or just plain tap water for that matter) as well as batteries made from lithium and air. The so-called water battery is supposed to one day achieve awe-inspiring energy densities (the amount of energy that can be stored in a battery of a given size) of 1,300 WH/kg for small batches and potentially 1,500 WH/kg at larger-scale production. For comparison, standard lithium-ion batteries have closer to 200 WH/kg to 400 WH/kg.
Envia is another startup that develops low-cost cathode materials for vehicle lithium-ion batteries, and it has found backing from car giant GM. And Amprius is a firm that makes lithium-ion batteries that it says can get four times more energy density compared to traditional batteries, due to a silicon nanostructured anode — the material that draws in the lithium ions when a battery recharges. Amprius is backed by Google’s former CEO Eric Schmidt, VantagePoint Venture Partners and Stanford University.
Beyond lithium ion
So what’s next after lithium-based batteries? Some companies and researchers are turning to different metals, elements and materials.
Pellion is a company trying to build the world’s first commercial magnesium battery, using magnesium as the cathode part of the battery (usually lithium is the cathode). Pellion says a magnesium battery could provide better performance and lower cost than current lithium-ion batteries. The company has an investment from Khosla Ventures and the Department of Energy’s high-risk energy stage grant program ARPA-E.
Liquid Metal Battery, another ARPA-E winner, has built a battery technology that sandwiches molten salt between two layers of liquid metal. The technology was the brainchild of MIT Professor Donald Sadoway (see our “15 questions for the don of liquid metal batteries”) and hopes to deliver a stable, low-cost, large-scale grid battery.
Or what about turning to widely available, basic materials like sodium and water? A Valley-backed startup called Aquion Energy is doing that and is looking to build modular batteries that can provide a slew of services for a cleaner power grid at a relatively low cost. Aquion executives believe these bulk storage devices will help solar and wind power give expensive natural gas “peaker” plants a run for their money as the go-to choice for meeting electricity needs during the periods of highest demand.
Cutting-edge manufacturing techniques will also shape the future of battery innovation. But the reality is that a lot of the manufacturing innovation will be done by Asian battery giants like Panasonic, which can use their economies of scale to invest in the latest tools.
However, smaller companies are looking to innovate in that area, too. Sakti3 is making battery cells on equipment that literally used to make potato chip bags, says the company. And a startup called Planar Energy Devices has built a pilot production line that can print its lithium-ion batteries onto sheets of metal or plastic.
Power management software
As the slow pace of battery innovation remains, software can step in and help extend battery life. Electric car companies Tesla and Coda Automotive have invested heavily in developing battery management systems that can keep batteries cool while being used to drive on highways.
Atieva is a four-year-old startup created by former Tesla Motors VP Bernard Tse. The company is working on software for monitoring individual battery cells and mechanical packaging and controls for vehicle battery packs. Using commodity cells, Atieva aims to produce customized packs primarily for smaller, independent car companies, and it recently won support from Chinese bus companies.
Battery business models
While batteries are still the most expensive part of an electric car and progress is slow, new business models are being used to route around the high cost of the EV battery. Car giant Renault as well as startup Better Place envision selling electric car battery charging like cell phone minutes, with leases for batteries built into that monthly fee.
Other companies are looking to recoup costs of expensive batteries by reselling them at different stages of life. Say a battery for an electric car has a warranty of seven years. If the battery is under a lease, after those seven years it can potentially be sold to utilities that could use it on the power grid for energy storage and frequency regulation.
The future of batteries
Unless we are going to grab an asteroid and introduce new materials on Earth, we are not going to achieve a Moore’s law for batteries anytime soon. But scientists still need to push the pace of progress as much as possible, discovering new combinations, designs and software. Why?
The battery is the single biggest roadblock to an always-on mobile world. It is the barrier — and a constant annoying reminder — that cell phones and laptops are not truly mobile and will always need to remain connected every few hours to the socket in the wall.
Batteries will be crucial to the future of transportation as well as the power grid. One day battery-powered cars will replace many gas-guzzling cars, and batteries will offer energy-storage services for utilities. A better battery in a decade will be fundamental to our changing cities and societies.