October 23, 2020: A variety of media reports in the week of October 12 said that increased demand for tin — a vital element in many lead battery alloys — was pushing up prices and that in the long term a price spike is on the way.
Tin prices are up 6.5% since January at $18,300/tonne, close to last month’s high of $18,510/t. Roughly half of all tin is used in soldering, lead-acid battery production accounts for a small section of the market.
Analysts at Macquarie Bank are forecasting that Chinese demand for the metal, which has become increasingly more essential for its role in electronics, will cause supply deficits every year until 2025. Analysts at Roskill forecast these deficits to continue until 2023.
The amount of tin added to lead batteries over the last 40 years has steadily been rising.
“In the mid-1970s the predominant grid alloy system for lead-acid batteries was based on antimony but contained around 0.2% tin to aid fluidity of the alloy during casting,” says Doug Lambert, vice president of sales and marketing at Wirtz Manufacturing.
By the mid-1980s, due to the technological shift towards low-maintenance and maintenance-free batteries, and high-speed continuous grid and plate manufacturing processes such as continuous casting, the alloy had changed to be based on binary lead-calcium and ternary lead-calcium-tin alloys.
“Early alloys contained tin in the range 0.2-0.7 wt.%, but by the mid-1990s, as a result of the extensive research into premature capacity loss, it was found that tin was needed on the positive plate to overcome the “antimony-free effect”. It was found that at least around 1% tin was needed but there were other beneficial effects with tin-rich alloys containing as much as 1.2 wt.% of the element.
“Today, we are seeing still further increases in the amount of tin used in grid alloys, particularly in the binary lead-tin system where tin contents in the range of 1.5-2.0 wt.% are not uncommon.”
Two years ago, the International Tin Association also noticed this trend for greater use of lead.
“Several indicators suggest that intensity of tin use in lead-acid batteries is increasing, both in continued transition from older flooded types to higher performance products and in increasing tin content of grid alloys,” the association said.
“Major supplier Exide previously published a grid alloy patent with ‘about 2%’ tin, up from the typical 0.7-1.5% tin. A 2016 patent from Panasonic had also specified higher levels of ‘2.3% tin or less’ to improve corrosion resistance particularly.
“Now an expert from a leading battery recycling company has reported increasing customer specifications in the positive plate by 0.1-0.2% tin and a major lead-acid producer expected overall tin use in 2017 would increase by almost 30%.
“This is likely to be at least partially in response to the increasing use of mild hybrid start-stop cars that require more advanced performance technology.”
Lambert takes this further: “With the world-wide use of high-speed continuous grid and plate manufacturing processes for lead-acid batteries used in transportation, industrial and reserve power applications, it is quite likely that we shall see a technological shift in grid alloy systems towards pure lead and lead-tin, while still continuing to use lead-calcium-tin alloys for specific applications.
“Which, on the basis of a supply and demand model with increased amounts of tin consumed in lead-acid cells and batteries, must surely result in another hike in the market price of tin.”
Tin is classified as a critical metal in the US, but not in the European Union. The EU has a major producer through Belgium’s Metallo, a recycling company now part of Germany’s Aurubis. The last US tin mine, by contrast, closed in 1993 and the last smelter in 1989.
The question bugging analysts in the tin market is what China thinks about the metal’s future in the longer term — should it, for example, be classified as a strategic commodity and large reserves be put in place?
China has been the world’s largest producer and consumer of tin for some years. However, recently, the country has grown heavily reliant on imports of raw material from tin mines in Myanmar, where there have been problems of supply and mine flooding. The coronavirus crisis has additionally exposed China’s dependency on its neighbour for tin concentrates.
China is now widely expected to include a stockpiling programme for strategic commodities in its next five-year plan beginning 2021, and tin could well be on this list.
According to the International Tin Association, research from the Massachusetts Institute of Technology showed that tin was a metal to ‘be most impacted by new technology’. The MIT said it saw it benefiting from all four factors — electric vehicles, renewable energy, advanced robotics and advanced computation and IT.
Macquarie says: “Some concerns have emerged around future supply from Myanmar, with market participants telling us that Chinese buyer inquiries are now reaching Africa and the new Alphamin mine in the Democratic Republic of Congo.”