Unknown schematic symbol in BQ27750EVM schematic by texas instruments
The "part" near the top is not actually a distinct part, but rather the multiple pins of the FET. From the FET datasheet, you see that the FET is a 5x2 BGA package; source 1 is on A1, B1, D1, and E1 while source 2 is on A2, B2, D2, E2:




The other parts (E1,E2...) are spark gaps to handle severe transients. They're a low cost approach to solving the same problem that a board-mounted gas discharge tube would.