Control system, control method and integrated circuit for secondary battery protection

A control method for execution by a device that monitors potentials at one or more negative electrodes of a plurality of secondary battery cells electrically coupled in series, each secondary battery cell being protected by a secondary battery protection circuit that controls at least one switching element provided in a given power path among a plurality of power paths, each power path being electrically coupled in series with a corresponding secondary battery cell among the plurality of secondary battery cells, the secondary battery protection apparatus including:

• an anomaly detecting circuit configured to detect an anomaly of the secondary battery cells,
• one or more monitoring terminals each provided in a path different from the power paths, each monitoring terminal being operable for monitoring a potential at a negative electrode of a given secondary battery cell among the plurality of the secondary battery cells,
• one or more internal lines, each internal line being between the negative electrode of the given secondary battery cell and a given monitoring terminal, and
• one or more internal switches, each internal switch being provided in a given internal line and configured to be turned on or off based on a result of anomaly detection performed by the anomaly detecting circuit, and the control method comprising:
• adjusting, based on potentials monitored by the one or more monitoring terminals, a current flowing into a line path that includes a corresponding internal line among the one or more internal lines;
• and
• controlling balance among the cell voltages for the plurality of the secondary battery cells, based on the adjusted current.

An integrated circuit for secondary battery protection, comprising:

• a plurality of power paths each electrically coupled in series with a corresponding secondary battery cells among a plurality of secondary battery cells electrically coupled in series;
• at least one switching element inserted in a given power path;
• one or more control circuits configured to control the at least one switching element such that the plurality of secondary battery cells are protected;
• an anomaly detecting circuit configured to detect an anomaly of the secondary battery cells;
• one or more monitoring terminals each provided in a path different from the power paths, each monitoring terminal being operable for monitoring a potential at a negative electrode of a given secondary battery cell among the plurality of the secondary battery cells;
• one or more internal lines, each internal line being between the negative electrode of the given secondary battery cell and a given monitoring terminal;
• and
• one or more internal switches, each internal switch being provided in a given internal line and configured to be turned on or off based on a result of anomaly detection performed by the anomaly detecting circuit,
• wherein the one or more monitoring terminals are configured to output respective monitored potentials, upon occurrence of a condition in which an external device adjusts, based on the potentials monitored by the one or more monitoring terminals, a current flowing into a line path that includes a corresponding internal line among the one or more internal lines, in conjunction with a condition in which the external device controls balance among the cell voltages for the plurality of the secondary battery cells, based on the adjusted current.