There is CR2032 size lithium metal battery made by RENATA in the HMI. Please see attached Article safety data sheet.
http://www.renata.com/fileadmin/downloads/techinfo/ASDS_Lithium_Metal_2017-12-15.pdf
http://www.renata.com/fileadmin/downloads/techinfo/ASDS_Lithium_Metal_2017-12-15.pdf