Tesla has purchased TCS for $1.9 billion.
The electric carmaker, which makes a line of electric cars, said it would “add more than 100 full-service and automotive-focused employees to the company” and said it will “make TCS a part of Tesla’s global supply chain.”
The purchase is the latest step in Tesla’s broader acquisition of businesses, including its solar-energy business.
Tesla has also bought a small battery startup, a solar-panel manufacturing business and a solar power company.
TCS is a global leader in consumer-grade lithium-ion batteries.
The company is based in Mountain View, California, and is owned by Tesla.
Tesla acquired TCS in April, and the deal was announced by CEO Elon Musk at the Tesla headquarters in Palo Alto, California.
Tesla shares have risen more than 40% this year.
In the first half of 2017, TCS reported earnings of $1 billion, up from $700 million in the same period a year earlier.
Tesla said in a statement that the acquisition will “help Tesla accelerate its transformation from a supplier of automotive batteries to a leading electric vehicle supplier.”