Panasonic investing over a billion $ in the Gigafactory

When completed, Tesla's Gigafactory will manufacture more batteries than the world makes right now. Panasonic, the current sub-contractor that supplies Tesla with batteries, is investing in the factory. This surprises me, as it implies that Panasonic will somehow benefit from the Gigafactory's output. I assumed that Tesla would cancel any outside supplier of batteries and use its own production to cut costs.

Read the article here: https://chargedevs.com/newswire/panasonic-will-spend-up-to-1-6-billion-on-tesla-gigafactory/