Balance charging circuit for series-connected storage cells and balance charging method for series-connected storage cells

摘要

A coil is electrically connected to one of storage cells to charge it, and after that, the coil is electrically connected to the other one thereof to charge it. In a first charging period, a path of a charging current flowing into a reference voltage through the coil is formed, in a second charging period, a path of a charging current flowing into a second cell from the coil is formed, in a third charging period, a path of a charging current flowing into the reference voltage through the coil is formed, and in a forth charging period, one end of the coil is electrically conducted with one end of the first cell and another end of the coil is electrically conducted with another end of the first cell to form a path of a charging current flowing into the first cell from the coil.

主权项

1. A balance charging circuit for series-connected storage cells for charging, in a balanced manner, a first storage cell and a second storage cell connected in series and having one series-connected end connected to an output terminal and another series-connected end connected to a reference voltage terminal, the balancing charging circuit comprising:
a coil provided in common for the first storage cell and the second storage cell and temporarily storing a power supplied from a power supply to charge the first storage cell and the second storage cell; and a switch section for electrically connecting the coil to one of the first storage cell and the second storage cell to charge the one of the first storage cell and the second storage cell, and then for electrically connecting the coil to the other one of the first storage cell and the second storage cell to charge the other one of the first storage cell and the second storage cell; wherein the switch section includes a plurality of switches for switching a path of a charging current flowing in the coil, the balance charging circuit further comprising: a control circuit for controlling the plurality of switches to be turned on and off and for setting repeatedly in turn a first charging period in which the coil is charged with a charging current to charge the second storage cell, a second charging period in which the second storage cell is charged with the charging current thus charged in the coil, a third charging period in which the coil is charged with a charging current to charge the first storage cell, and a fourth charging period in which the first storage cell is charged with the charging current thus charged in the coil, wherein: in the first charging period, the control circuit controls the plurality of switches to be turned on and off to form a path of a charging current flowing into the reference voltage terminal through the coil; in the second charging period, the control circuit controls the plurality of switches to be turned on and off to form a path of a charging current flowing into the second storage cell from the coil; and in the third charging period, the control circuit controls the plurality of switches to be turned on and off to form a path of a charging current flowing into the reference voltage terminal through the coil; and in the fourth charging period, the control circuit controls the plurality of switches to be turned on and off to electrically conduct one end of the coil to one end of the first storage cell, electrically conduct another end of the coil to another end of the first storage cell, and form a path of a charging current flowing into the first storage cell from the coil; wherein the plurality of switches includes: a first switch having one end connected to a contact point where the first storage cell and the second storage cell are connected to each other, a second switch having one end connected to an input terminal, a third switch having one end connected to the reference voltage terminal, a fourth switch having one end connected to the output terminal, a fifth switch having one end connected to the reference voltage terminal, and a sixth switch having one end connected to the contact point where the first storage cell and the second storage cell are connected to each other, wherein one end of the coil is connected to another end of the first switch, another end of the second switch, and another end of the third switch, and another end of the coil is connected to another end of the fourth switch, another end of the fifth switch, and another end of the sixth switch, and wherein in the first charging period, the control circuit turns on the second and sixth switches and turns off the first, third, fourth, and fifth switches, in the second charging period, the control circuit turns on the third and sixth switches and turns off the first, second, fourth, and fifth switches, in the third charging period, the control circuit turns on the second and fifth switches and turns off the first, third, fourth, and sixth switches, and in the fourth charging period, the control circuit turns on the first and fourth switches and turns off the second, third, fifth, and sixth switches.