EV batteries getting cheaper

EV batteries getting cheaper

Earlier this year, Telsa Motors made headlines when it announced that the company would start selling Tesla-branded stationary storage batteries. The move was expected, but a bit oddbattery storage for homes has been around for years, but it has never really been cost-effective enough in most households to merit the kind of treatment that Tesla gave it. While Tesla successfully nurtured a luxury electric vehicle market, it still seemed out of place to see a luxury brand going out of its way to put car batteries on homes.

Ars argued that the real news behind Tesla's stationary storage announcement was not that of the consumer-focused Powerwall, but that of the power pack, Tesla's stationary battery system for industrial use cases.

The truly surprising part of Tesla's Powerwall announcement, however, was its price point. In 2014, the average cost of installing a stationary Li-ion battery in a California home was $23,429, according to The Wall Street Journal. In May, Tesla CEO Elon Musk said that these batteries would start at $3,500, plus a $500 installation cost.

It's no secret that Li-ion battery packs have been getting cheaper, and it's unsurprising that Tesla, would experience some economies of scale to allow that kind of price point (whether or not the price is subsidized by the company). And the price is only likely to come down, as the company is in the process of building a massive gigafactory outside of Reno, Nevada, with Panasonic to produce Li-ion batteries. Beyond Tesla, however, a recent paper published in Nature Climate Change gathered data to confirm that the cost of Li-ion battery packs for electric vehicles are falling for everyone. If trends continue, the paper suggests, electric vehicle battery packs and their stationary brethren could compete more effectively against gas cars and backup generators not too far into the future.

The research suggests that the cost of producing battery packs for electric vehicles has fallen dramatically between 2007 and 2014, to lower price points than previous optimistic projections had expected. Results show that costs in 2014 were probably already below average projected costs for the 2020 time frame, Bjrn Nykvist and Mns Nilsson wrote in their recent paper.

Nykvist and Nilsson say their data indicate that battery pack costs will continue their precipitous decline, perhaps even reaching the point where Li-ion battery systems on electric vehicles reach parity with gas-guzzling vehicles. (Although the authors of the paper admit that this point, if we ever reach it, is still far in the futurenot something we're likely to see this year or next.)

The single most important factor in achieving a compelling and affordable mass-market BEV [battery electric vehicle] is its relative cost, Nykvist and Nilsson wrote. It is commonly understood that the cost of battery packs needs to fall to below US$150 per kWh in order for BEVs to become cost-competitive on par with internal combustion vehicles.

Nykvist is a research fellow at the Stockholm Environment Institute (SEI), and Nilsson is the Research Director at SEI. The two aggregated cost estimates for electric vehicle battery packs that were found in scientific journals as well as estimates found in the most cited grey literature, including estimates by agencies, consultancy and industry analysts; news items of individual accounts from industry representatives and experts; and, finally, some further novel estimates for leading BEV manufacturers. The two researchers did not distinguish between different variants of Li-ion battery chemistry because there was too little data to break out each technology separately, nor did they take into account the costs of hybrid car batteries.

What they found was that the cost of battery backs for electric vehicles has decreased from about $1,000 per kWh in 2007 to about $450 per kWh in 2014. And that's taking all battery electric vehicle manufacturers into account. When you separate out the largest companies making electric vehicles, the cost reductions get even more dramatic. [T]he cost of battery packs used by market-leading BEV manufacturers are even lower, at US$300 per kWh, the researchers added.

The authors admitted that their data was imperfect due to secrecy surrounding business deals. But public statements made by electric vehicle makers were used to confirm some of the numbers that the researchers found. Current average cost at US$300 per kWh for market-leading actors in 2014 is, however, very close to key information given by Tesla Motor chief engineer JB Strubel, the paper asserts, who has indicated in 2013 that the costs of the Tesla Model S battery pack is below 25 percent of the total costs of the car in most cases, corresponding to approximately US$310 per kWh. Similarly, other industry experts have also estimated that battery packs in general make up 25 percent of vehicle prices, which corresponds to approximately US$300 per kWh, for example, Nissan Leaf in 2014.

To explain the shift, the researchers measured what they called the learning rate, which they defined as the cost reduction following a cumulative doubling of production. For BEV manufacturers around the world, the learning rate was found to be between 6 and 9 percent. And that rate could climb: There are still R&D improvements to be made in, for example, anode and cathode materials, separator stability and thickness, and electrolyte composition, Nykvist and Nilsson wrote. Among these factors, input material cost is among the most important, and costs as low as US$300 per kWh due to such improvements have been discussed. Together with improvements due to economies of scale, a 12-14 percent learning rate is conceivable.

Source: ars techinca

SMART GRID Bulletin November 2017


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