At 100,000 miles it is recommended to change the battery coolant... Searching amazon for the GM part number (12378390) I get this... {https://www.amazon.com/Genuine-GM-Coolant-Part-12378390/dp/B00TABA3QQ}... Maybe this helps.

From the manual: High Voltage Battery Cooling System Premix DEX-COOL (GM Part No. 12378390, in Canada 10953456).