While Panasonic has been Tesla’s longtime partner for battery cell supply, the automaker confirmed last year that for the first time it approved a cell from another manufacturer, LG Chem, but only for a small contract for its Roadster 3.0 upgrade. Now we learn that Tesla started taking delivery of much larger quantities of battery cells from yet another supplier: Samsung SDI.

A bill of lading between Tesla Motors and Samsung SDI at the Oakland port shows that the automaker took delivery of over 120 tons of Samsung SDI 18650 battery cells – the same format Tesla sources from Panasonic.

We contacted Tesla representatives and asked if the company was able to confirm what the cells will be use for as the quantity appears to be excessive for testing (enough for over 100 cars) or a project like the Roadster battery pack upgrade (though not impossible). We will update when we have more information.

The battery cells could also be used in Tesla Energy products, like Powerpacks and Powerwalls.

The shipment arrived in Oakland on April 19, 2016:

Unconfirmed reports of a battery supply negotiation between Tesla and Samsung came to light in October 2015 – right when the company confirmed using LG’s cells for the Roadster battery pack upgrade.

Recent reports from South Korea published last month suggested that Tesla executives recently met with the country’s top three battery suppliers, LG Chem, Samsung SDI and SK Innovation, to negotiate new battery supply agreements.

While Panasonic remains Tesla’s main battery supplier and partner in the Gigafactory, the automaker always made clear that the company will looking to diversify its battery supply chain.

Since last year, the company notes its ability to source battery cells from multiple vendors in its SEC filings:

We believe our ability to change battery cell chemistries and vendors while retaining our existing investments in software, electronics, manufacturing equipment, testing and vehicle packaging, will enable us to quickly deploy various battery cells into our products and leverage the latest advancements in battery cell technology.

In the same filing, the company said that it had already selected several sources for the battery cells, but qualified only one cell (18650 from Panasonic) for its battery pack and Tesla expects qualifying additional cells from other manufacturers “in 2015”. LG’s cells for the Roadster were likely among those.

Earlier this week, we also reported on interesting comments made by Tesla CEO Elon Musk about the fact that the company could potentially triple the total planned battery output of the Gigafactory to ~105 GWh of cells and ~150 GWh of battery packs – or over 3 times the current total li-ion battery production worldwide.

The difference in battery cells (between 15 GWh and 45 GWh depending on output) would be imported from other sources – presumably from Panasonic’s other battery factories, but possibly also other suppliers.

Musk also confirmed that Tesla plans to manufacture slightly bigger cells at the Gigafactory than what the automaker is currently using from Panasonic, and now apparently Samsung: 20700 instead of 18650.

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