Cell count determination device, charger, battery pack, and charging system

A cell count determination device that is configured to determine a cell count of a battery pack having installed therein a plurality of battery cells, the cell count determination device comprising:

• a plurality of switch elements, each of which includes a first terminal, a second terminal, and a third terminal;
• and
• a determination unit that is configured to determine the cell count of the battery pack based on a combination of potentials of the second terminals of the plurality of switch elements,
• wherein, in each of the plurality of switch elements,
• the first terminal is connected to a highest-potential unit having a highest potential in the battery pack,
• the second terminal is connected to a lowest-potential unit having a lowest potential in the battery pack,
• the third terminal is connected to any of a plurality of intermediate-potential units having a potential of a connection point between battery cells installed in the battery pack, or is connected to the highest-potential unit, and
• a conductive state between the first terminal and the second terminal is determined based on a voltage difference between the first terminal and the third terminal.

A cell count determination device that is configured to determine a cell count of a battery pack having installed therein a plurality of battery cells, the cell count determination device comprising:

• a plurality of switch elements, each of which includes a first terminal, a second terminal, and a third terminal;
• and
• a determination unit that is configured to determine the cell count of the battery pack based on a combination of potentials of the second terminals of the plurality of switch elements,
• wherein, in each of the plurality of switch elements,
• the first terminal is connected to a lowest-potential unit having a lowest potential in the battery pack,
• the second terminal is connected to a highest-potential unit having a highest potential in the battery pack, or is connected to a fixed potential unit having a predetermined potential,
• the third terminal is connected to any of a plurality of intermediate-potential units having a potential of a connection point between battery cells installed in the battery pack, or is connected to the lowest-potential unit, and
• a conductive state between the first terminal and the second terminal is determined based on a voltage difference between the first terminal and the third terminal.