TH15992A - A monitor for monitoring the operating parameters of the battery. - Google Patents

Abstract

The Battery Monitor (10) monitors the operating parameters of the battery to provide indications of the complete charge status, relative charge status, and battery power size under discharge and recharge conditions. The Battery Monitor (10) includes a current detector (18) to detect battery current, a voltage detector (20) to detect battery voltage, and a temperature detector (22) to detect battery temperature, among others. The Evaluator (26) evaluates the battery parameters with high accuracy using an iterative process based on predetermined relationships, using empirical constants determined by the parameters determined in previous iterations stored in memory. Output signals indicating the determined parameters are prepared and used for a variety of battery applications.

Claims (17)

1. Battery monitor for monitoring the operating parameters of the battery (12). The battery monitor is a type of monitor that includes a voltage detector (20) to detect the voltage of the battery (12) and provide a voltage detector signal indicating the voltage of the battery (12), a current detector (18) to detect the current of the battery (12) and provide a current detector signal indicating the current of the battery (12), and a processor (26) to read the voltage detector signal and the current detector signal. The battery monitor is characterized by a memory unit (30) attached to the processor (26), an output terminal (32) attached to the processor. The battery monitor is characterized as follows: The processor (26) finds the operating parameters of the battery (12) at calculation times apart. The processor stores one of the last selected operating parameters in memory (30). The processor (26) finds one of the found operating parameters. Before each calculated time interval responds to the current detector signal, voltage detector signal and one of the last determined operating parameters are stored and the output terminal (32) provides an output signal that is an indication of one of the previously determined operating parameters. 2. The battery monitor under claim 1 is characterized as follows: one of the predetermined operating parameters is the battery's (12) complete charge state; and when the battery (12) is in a discharge state, the processor (26) determines the factor representing the difference between the battery's (12) complete charge state and the battery's (12) relative charge state. The battery's (12) complete charge state is the sum of the battery's (12) relative charge state and the battery's (12) relative charge factor dependent on the corrected battery voltage and the corrected battery voltage in response to the voltage sensor signal and the current sensor signal. 3. The battery monitor, as defined in claim 2, shall be further characterized by a temperature sensor (22) to detect the temperature of the battery (12) and provide the processor (26) with a temperature sensor signal indicating the temperature of the battery (12), and that the processor (26) determines the battery voltage and corrects the response to the temperature sensor signal. 4. The battery monitor, as defined in claim 2, shall be characterized by a processor (26) that stores the last read current detector signal and the last found factor of the battery (12) in memory (30), that the processor (26) determines the rated power size of the battery (12) and the current size of the battery (12), and that the processor (26) determines the factor dependent on the rated power size of the battery (12), the current size of the battery (12), the last found factor stored of the battery (12), the time since the last finding, and the last read current detector signal stored. 5. The battery monitor, as defined in claim 4, shall be further characterized by a temperature sensor (22) to detect the temperature of the battery (12) and provide the processor (26) with a temperature sensor signal indicating the temperature of the battery (12), and that the processor (26) responds to the temperature sensor signal to determine the temperature compensation to determine the battery power rating (12) and the battery current rating (12). 6. The battery monitor under claim 1 is defined as follows: When battery (12) is in a idle state, the processor (26) determines the open-circuit voltage of battery (12) in response to the voltage and current sensor signals, and the open-circuit charging state of battery (12) from the open-circuit voltage. 7. The battery monitor, as defined in claim 6, shall be characterized as follows: that one of the parameters to be determined is the complete charge state of the battery (12), and that the processor (26) determines whether the open-circuit voltage charge state is correct, and that the complete charge state of the battery (12) is set equal to the open-circuit voltage charge state of the battery (12) when the processor (26) determines whether the open-circuit voltage charge state is correct. 8. The battery monitor, as defined in claim 7, is characterized as follows: the processor (26) determines the open-circuit charging state when the battery (12) has been in the open-circuit charging state for more than one period. 9. The battery monitor, as defined in claim 8, is further characterized by a timer (24) to determine the time at which the battery (12) is in an overdue state. 10. The battery monitor, as defined in claim 8, is characterized as follows: when battery (12) is in an overcharge state for a second time, the processor (26) adjusts the complete charge state of battery (12) to match the open-circuit charge state of battery (12), and adjusts the complete charge state of battery (12) to be within the specified range if the open-circuit charge state of battery (12) is outside the specified range. 11. The battery monitor under claim 2 is characterized as follows: that the processor (26) limits the calculated relative charge state of the battery (12) and stores the limit relative charge state of the battery (12) in memory (30); and that the processor (26) limits the calculated relative charge state of the battery (12) between the difference between the last stored limit relative charge state and the amount of first-order charge constant time used by the battery (12) and the difference between the last stored limit relative charge state and the amount of second-order charge constant time used by the battery (12). 12. The battery monitor, as defined in claim 1, is characterized as follows: when battery (12) is in a recharged state, the processor (26) will find the gassing current of battery (12) in response to a voltage sensor signal. Such gassing current represents the amount of recharge current that is not used to recharge battery (12). 13. The battery monitor under any one of the claims 1 through 12 is characterized as follows: the processor (26) determines whether the battery (12) is in a state beyond recharge or discharge in response to a current sensor signal. 14. The battery monitor pursuant to claim 1 shall be characterized as follows: that one of the pre-determined operating parameters shall include at least one operating parameter of the operating parameter set which includes the relative charge state of the battery (12), the full charge output power of the battery (12) at a given discharge current, the residual charge output power of the battery (12) at a given discharge current, the time to discharge the battery (12) as indicated by the time at which the battery (12) will be fully charged at a given discharge current, the amp-hours required to fully recharge the battery (12), the time to fully recharge the battery (12) at a given discharge current, the recommended discharge voltage to recharge the battery (12), and the critical restart temperature of the battery (12). 15. The Battery Monitor (10), according to claim 1, is characterized as follows: that one of the parameters to be determined is the complete charge state of the battery (12), and that the processor (26) at each time calculates and stores in memory (30) the factor representing the difference between the complete charge state of the battery (12) and the relative charge state of the battery (12) by determining when the battery (12) is in a recharged state, the difference between the factor stored in memory (30) and the recharge state of the battery (12) from the last calculated time, and that the processor determines the relative charge state of the battery (12) in response to the complete charge state of the battery (12) and the factor to be determined and stored in memory (30). 16. A method for monitoring the complete charge status of a rechargeable battery (12). The method is characterized by the procedure of receiving the battery voltage (12) and providing the voltage sensor signal to the processor (26), receiving the battery current and providing the current sensor signal to the processor (26), enabling the processor (26) to calculate a) the rated power of the battery (12), b) the current power of the battery (12), c) the charge state used by the battery (12), d) the battery factor (12), e) the complete charge status of the battery (12), and g) the relative charge status of the battery (12), and providing an output signal indicating the complete charge status of the battery (12). 17. The method pursuant to claim 16 is further characterized by the procedure for calculating the charge state used by the battery (12) when the battery (12) is in a recharged state by multiplying the difference between the gasing currents calculated from the voltage sensor signal and the current sensor signal by the time since the last calculation and dividing by the nominal power size of the battery (12) (Clause 17, page 6, figure 5).