Battery pack for supplying electric power to a power tool

A battery pack for supplying electric power to a power tool, comprising:

• a housing detachably mounted to the power tool;
• a first battery cell disposed in the housing and supported by the housing, wherein the first battery cell has a first power density;
• a second battery cell disposed in the housing and supported by the housing, wherein the second battery cell has a second power density, and a ratio of the second power density to the first power density is greater than or equal to 2;
• and
• a terminal assembly electrically connected to the first battery cell and the second battery cell to transmit electric power from the first battery cell and the second battery cell to the power tool.

A battery pack for supplying electric power to a power tool, comprising:

• a housing detachably mounted to the power tool;
• a first battery cell disposed in the housing and supported by the housing, wherein the first battery cell has a first energy density;
• a second battery cell disposed in the housing and supported by the housing, wherein the second battery cell has a second energy density, and a ratio of the second energy density to the first energy density is greater than or equal to 1.5;
• and
• a terminal assembly electrically connected to the first battery cell and the second battery cell to transmit electric power from the first battery cell and the second battery cell to the power tool.