New Developments in Battery Technology

On November 2, 2015, in Technology Update, by sharilee

Tech companies and car manufacturers are making big investments in battery technology. And for good reason. Sales of electric vehicles (EVs), including battery-electric vehicles (BEVs) and plug-in hybrid vehicles (PEVs) are soaring, especially in the EU where gasoline prices are 2-4x higher than in the U.S. IncHEVreased use of mobile devices is also driving the need for battery innovations, even as chips and operating systems are designed to be more efficient and save power. The latest IDC Worldwide Quarterly Mobile Phone Tracker shows 6.8% growth in smartphone units shipped in Q3 2015 vs Q3 2014 to over 355 million units. Add to that, growth in wearables, laptops, tablets, and smart homes.

But battery technology has been slow to change over the years. Li-Ion has dominated to date because a lithium anode has a high energy density and is lightweight. In an interesting article, “Why We Don’t Have Battery Breakthroughs” in MIT Technology Review, Kevin Bullis writes:

One difficult thing about developing better batteries is that the technology is still poorly understood. Changing one part of a battery—say, by introducing a new electrode—can produce unforeseen problems, some of which can’t be detected without years of testing.

In startup Envia, they had licensed a promising material developed by researchers at Argonne National Laboratory. Subsequently, a major problem was discovered. The problem—which one battery company executive called a “doom factor”—was that over time, the voltage at which the battery operated changed in ways that made it unusable. Argonne researchers investigated the problem and found no ready answer. They didn’t understand the basic chemistry and physics of the material well enough to grasp precisely what was going wrong, let alone fix it.

The single most important factor in achieving a mass-market BEV is cost. “Estimates are that the cost of battery packs needs to fall to below US$150 per kWh for BEVs to become cost-competitive with internal combustion vehicles,” said Bjorn Nykvist and Mans Nilsson in their Nature Climate Change paper, “Rapidly falling costs of battery packs for electric vehicles.” For Li-Ion battery packs, costs have decreased over the last 8 years, from above US$1,000 per kWh to around US$300 per kWh.

Innovations in Li-Ion Battery Design

New developments show much promise. According to Brookings Institution’s TechTank blog:

Lithium heats up and expands during charging, causing leaked lithium ions to build up on a battery’s surface. These growths short-circuit the battery and decrease its overall life. Researchers at Stanford recently made headway on these problems by forming a protective nanosphere layer on the lithium anode that moves with the lithium as it expands and contracts.

Screen Shot 2015-11-02 at 10.00.19 AM

Figure 1. Movement of lithium ions and electrons in a Li-Ion battery during charging and use.

Israeli startup StoreDot has developed a new type of Li-Ion battery that it says can be fully charged in a few minutes. In a standard Li-Ion battery, the internal resistance blocks the flow of the current and makes it more difficult to deliver spikes of power. StoreDot is using bio-organic peptide “nanodots” to make very thin battery electrodes with supercapacitor-like rapid charging and a Li-Ion-like slow discharging.

Beyond Lithium Ion

Researchers at BASF recently doubled the amount of energy that can be stored in an older type of battery, nickel-metal hydride, now used in HEVs. This makes them comparable to Li-Ion batteries in terms of storage, but with the advantage of increased safety. They don’t use flammable liquids, so their cooling systems and electronic controls are simpler. The scientists changed the microstructure of the batteries to make them more durable and lighter. They can store 140 watt-hours per kilogram. Li-Ion can store up to 230 watt-hours per kilogram, but the added weight counters that advantage.

Scientists at UCLA’s California NanoSystems Institute have developed a hybrid device that goes beyond simple changes in battery cell chemistry. According to Green Car Reports:

The experimental device combines the energy density of a lead-acid battery with the quick charge and discharge rates of a supercapacitor. It’s six times as energy-dense as the average commercial supercapacitor. That combination of qualities has great potential impact for electric cars. It would theoretically offer more compact energy storage and faster charging without sacrificing range.

Researchers claim the version being tested can hold twice as much charge as a typical thin-film lithium battery–but on a surface one-fifth the thickness of a piece of paper. This performance was reportedly achieved by maximizing the contact area between the electrolyte and the two electrodes. Those electrodes are made from manganese dioxide, but feature a three-dimensional laser-scribed graphene (LSG) structure.

Second Life Battery Applications

EV batteries lose their ability to propel a vehicle over time.There is a growing market for EV batteries in after-life commercial applications, such as power generation on the grid. GM, for instance, is using the Volt battery system to supplement renewable power gen at one of its facilities, making the facility a net zero building. Nissan and Green Charge have developed ex-EV battery systems that companies can use to manage their utility demand charges, substituting battery power for electricity from the grid during peak pricing.

Eventually, carmakers will incorporate EV batteries while they’re still installed in cars, using vehicle-to-grid (V2G) systems. Such an approach promises better regulation of frequencies on the grid to smooth the power loads and lower usage during peak demand periods. The U.S. Department of Defense has invested $20 million in the DoD Plug-In Electric Vehicle Program, which has so far installed 500 V2G-enabled vehicles at bases in the states. This program has shown that frequency regulation alone can reduce the monthly lease price of a plug-in electric sedan by 72%.

Open-Cell-vs-Closed-Cell-photos

Regardless of the application, batteries need to be packaged to absorb internal impact energy. PORON® polyurethane and BISCO® silicone foams withstand collapse that can happen due to the stresses of compression and temperature in battery packs over time. This Compression Set Resistance (C-set resistance) can help extend the life of the battery by continuing to seal and absorb shock. These unique foams from Rogers Corporation also have a unique ability to act as a spring by retaining a very consistent level of force across a range of compressions. This allows the designer more flexibility and reliability in packaging of the battery pack due to the ability to predict the cushioning material’s behavior across varied dimensional tolerances.

Tangible improvements in battery technology are surfacing. This will have a significant impact on our use of EVs and mobile devices, and, when combined with developments in renewable energy, will drive interesting global changes in economic and political norms.

One Response to New Developments in Battery Technology

  1. Quite interesting article. One comment on the video. The student all the positive electrode a cathode. I guess it is a mistake
    Nevertheless a cannot wait to hear more about the new type of battery described
    -Liviu

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