A battery signalling system is provided which can be used to monitor and/or control a battery (1) having a number of series connected battery cells (C.sub.i). When used to monitor the battery cells, the battery signalling system can comprise a central battery monitoring system (3) for monitoring the industrial battery (1) as a whole, a number of cell monitoring devices (CM.sub.i) for monitoring one or more battery cells (C.sub.i) and a communication link (9) for connecting the cell monitoring devices (CM.sub.i) in series in a daisy chain configuration to the central battery monitoring system (3). In operation, the central battery monitoring system (3) can poll each of the cell monitoring devices (C.sub.mi) in turn and analyze the data received from a polled cell monitoring device (CM.sub.i) to detect malfunctions and/or underperforming cells.
This application is a Continuation of application Ser. No. 09/362,624 filed on Jul. 20, 1999 now U.S. Pat. No. 6,155,709, which is a Continuation-in-Part of International Application No. PCT/GB98/00170 filed Jan. 20, 1998.
Priority Data
Jan 21, 1997 [GB] 9701165 Aug 22, 1997 [GB] 9717967 Sep 19, 1997 [GB] 9720037 Jul 21, 1998 [GB] 9815899 Nov 26, 1998 [GB] 9825954
A method for determining the internal impedance of each battery cell within a system including at least one parallel string of serially connected battery cells without disconnecting the battery cells from the system, which initially makes measurements of two battery cells within each string to calculate the internal impedance of each of those two battery cells and to calculate a common impedance multiplier term for the rest of the battery cells in each string. The remaining battery cells in each string are individually measured and the common impedance multiplier term for that string is used to account for measured current which comes from the Thevenin equivalent voltage source of the rest of the system, in addition to current drawn from the battery cell being measured.
The present invention relates to a battery management system and method. In some embodiments the battery management system includes a sensing unit and a micro controller unit (MCU). The sensing unit measures the current, the voltage and the temperature of a battery. The MCU receives the voltages, the currents, and the temperatures, calculates an estimated cell voltage, by applying a pack voltage sensing error and the cell voltage deviation to the cell voltages, and calculates an estimated cell resistance, by adding a pack assembly resistance to an internal resistance of the cell, and calculates an pack output of the battery by using the estimated cell voltage and the estimated cell resistance.
An apparatus and method for monitoring at least one battery. A reference ramp voltage signal is applied to a battery. A difference between a measurement ramp voltage signal output from the battery and the reference signal is compared with a threshold to determine battery condition. The determined battery condition can be transmitted remotely from the battery location.
An integrated battery monitoring device includes a pair of input leads for coupling across the terminals of a battery cell to be monitored and a sensor for sensing a desired battery cell parameter. A self-contained power supply has the voltage across the battery cell terminals as an input thereto, the self-contained power supply being configured for providing power to the sensor. A pair of output leads communicates data generated by the sensor.
