Gigafactory announcements have been trending in recent months, with plans for at least 10 new plants revealed in the last six months. Half a dozen have been planned in the last month alone.

In Germany, for example, the Daimler subsidiary Accumotive laid the foundation for a $550 million plant designed to take annual lithium-ion battery production from its current level of 80,000 units up to around 320,000.

And Energy Absolute, of Thailand, reportedly has plans for a $2.9 billion factory in Asia, with an annual production capacity of 1 gigawatt-hour per year, scaling to 50 gigawatt-hours a year by 2020.

Meanwhile, a consortium including Boston Energy and Innovation (BEI), Charge CCCV, C&D Assembly, Primet Precision Materials and Magnis Resources confirmed it will build a 15-gigawatt-hour-a-year plant on IBM’s former Huron Campus manufacturing site in New York.

BEI, Charge CCCV, C&D Assembly and Magnis Resources are also working with Eastman Kodak Group to build a similarly sized plant near Townsville in Queensland, Australia. The backers have said the plant could create around 7,000 jobs.

More recently a company called Energy Renaissance has lifted the lid on plans for a factory in Darwin, in Australia’s Northern Territory, with a production capacity of a gigawatt-hour of batteries a year.

The most aggressive gigafactory plans, however, remain with the company that came up with the concept. Tesla’s Elon Musk has said he will announce “probably four” new gigafactories this year. One has long been slated for Europe, and another has been confirmed to be in the works in Shanghai, China.

The recent announcements follow at least five gigafactory proposals put forward for Europe before the end of last year, including facilities in Sweden, Hungary and Poland. Not all the new plants will focus on lithium-ion batteries, though.

The U.S. lead-acid battery maker Johnson Controls, for example, unveiled proposals for two Chinese plants with a combined annual capacity of 13.5 million batteries.

The company already has production capacity for 16 million batteries a year, from a factory in Chongqing and one in Zhejiang, and is looking invest $250 million in a new plant that could produce up to 7.5 million units a year in Shandong from 2019.

A second plant would follow in 2020. The increased capacity is aimed at satisfying growing demand from the start-stop engine market.

Overall, Bloomberg reports that global battery-making capacity is set to more than double by 2021, topping 278 gigawatt-hours a year compared to 103 gigawatt-hours at present.

The massive planned increase in battery production feels similar to the Chinese manufacturing boom that radically altered the PV landscape around a decade ago, by creating oversupply that ultimately led to the demise of dozens of solar firms.

Could the same phenomenon be underway in battery manufacturing?

Probably not, say storage experts. The pricing declines won't be nearly as dramatic due to supply chain differences.

"Unlike PV, battery raw materials are rare metals that have to be mined and processed, so they will have constant supply-demand push-pull, minimizing risk of supply glut," said Ravi Manghani, director of GTM Research's storage practice.

"The industry is in the middle of a huge cost declines phase as manufacturers continue to bring large gigafactories on-line. While some individual vendors may see massive cost step-downs as facilities are activated or new generation products with superior density are launched, on a macro level, the declines are going to be much more gradual," said Manghani.

According to Logan Goldie-Scot, head of Bloomberg New Energy Finance's storage practice, the growth in production capacity is already considered in pricing forecasts.

“We're already factoring the ramp-up in production capacity and ongoing price decreases into our analysis,” said Goldie-Scot. “I don't foresee a step-change reduction in price.”

By 2030, BNEF expects battery pack prices to fall to $73 per kilowatt-hour, down from a volume-weighted average of $273 per kilowatt-hour in 2016.

“This is an average, though,” he said. “We're already seeing pack prices below $200 per kilowatt-hour.”

David Hart, director at E4tech, an international strategic consultancy focused on sustainable energy, said much of the upcoming capacity will be needed to satisfy forecast growth in vehicle electrification.

“Building gigafactories is a logical next step in creating a battery industry that's fit for the purpose of supplying vehicles,” he said. “I don't think the rise in gigafactories will necessarily result in a price crash.”

Even if the battery market is unlikely to face the same pressures as solar, it will still grapple with challenges of its own.

“Very importantly, it's not clear that the resource supply chains exist yet for all these factories,” Hart said. “Lithium and cobalt supply needs to be increased, and everyone is vying for supply.”