Research on secondary batteries enabling charge and discharge, unlike primary batteries, which typically cannot be charged, has been actively conducted, with the development of high-technology fields, such as digital cameras, cellular phones, notebook computers, and hybrid cars. Secondary batteries may include a nickel-cadmium battery, a nickel-metal hydride battery, a nickel-hydrogen battery, a lithium secondary battery, etc. The voltage of such a secondary battery is measured using a battery test apparatus, as shown in FIG. 1. When the measured voltage is less than or greater than a reference voltage, the battery is charged or discharged, and thus voltage balance is realized.
FIG. 1 is a diagram showing a conventional apparatus for testing batteries.
Referring to FIG. 1, the conventional battery test apparatus includes a switch unit 6 and a circuit unit 2.
The switch unit 6 is connected to N batteries 4, and functions to connect the batteries to the circuit unit 2. Such a switch unit 6 includes N+1 switches S1 to Sn+1. The first ends of the first to N-th switches S1 to Sn are connected to the cathodes of the first to N-th batteries B1 to Bn, respectively, and the N+1-th switch Sn+1 is connected to the anode of the N-th battery Bn.
The circuit unit 2 is implemented using voltage circuits or resistance circuits. That is, when the first to N-th circuits, included in the circuit unit 2, are voltage circuits, the circuit unit 2 measures the voltages of respective batteries B1 to Bn. When the first to N-th circuits are resistance circuits, the circuit unit 2 functions to decrease the voltages of the batteries measured by voltage circuits when the measured voltages are greater than a reference voltage.