Tesla Motors refers to the Roadster's battery pack as the Energy Storage System or ESS. The ESS contains 6,831 18650 Lithium Ion Cells arranged into 11) "ESS Sheets" all connected in series. Each sheet contains 9) "bricks" connected in series. Each "brick" contains 69 cells connected in parallel. The individual cells are identical to the cells used in Vape Smoke Devices and Laptop battery packs. Here is a picture of one of eleven individual ESS Sheet out of the Roadster Battery Pack. We positioned the sheet to show the plumbing lines, and the Battery Management System (BMS) board toward the bottom. There are two aluminum sheets on each Brick to collect the plus and minus connections from each individual cell. The connection is made with a thin wire fusible link from each 18650 cell to the aluminum brick sheet.