BATTERY LIFE PREDICTING DEVICE AND BATTERY LIFE PREDICTING METHOD

• US 20090037145A1
• Filed: 02/23/2007
• Published: 02/05/2009
• Est. Priority Date: 02/28/2006
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Takeshima, Hiroki, Suzuki, Tatsuhiko
• Granted Patent: US 8,035,395 B2
• Time in Patent Office: Days
• US Class Current: 702/183
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health

Abstract

A battery life predicting device and a battery life predicting method capable of accurately predict the lifetime of storage batteries are provided.

The expected lifetime value selecting unit 7 selects, as an expected lifetime value, a lifetime value that corresponds to the load power applied by the storage battery during discharge and the ambient temperature of the location where the storage battery 3 is installed while referring to the lifetime data stored in the lifetime data storing unit 5, the first diminution in lifetime calculating unit 12a calculates the first diminution in lifetime based on a natural logarithm function that takes the time obtained by converting the number of discharge cycles of the storage battery 3 as a variable, the second diminution in lifetime calculating unit 12b calculates the second diminution in lifetime from the mean value of the storage battery temperatures during charging, discharging or an idle state, the ambient temperature and the time elapsed after the installation of the storage battery 3, and the remaining lifetime value calculating unit 12c calculates the remaining lifetime value by subtracting the first diminution in lifetime and the second diminution in lifetime from the expected lifetime value.

Claims

1. A battery life predicting device comprising:

a lifetime data storing unit for storing lifetime data that shows the relationship between the load power applied by a storage battery during discharge and the ambient temperature of the location where the storage battery is installed, and the lifetime of the storage battery;

a load power measuring unit for measuring the load power applied by the storage battery;

an ambient temperature measuring unit for measuring the ambient temperature;

an expected lifetime value selecting unit for selecting, as an expected lifetime value, a lifetime that corresponds to the load power measured by the load power measuring unit and the ambient temperature measured by the ambient temperature measuring unit while referring to the lifetime data stored in the lifetime data storing unit;

a discharge cycles counting unit for counting the number of discharge cycles of the storage battery;

a first diminution in lifetime calculating unit for calculating a first diminution in lifetime which decreases the expected lifetime value based on a natural logarithmic function that takes the time obtained by converting the number of discharge cycles counted by the discharge cycles counting unit as a variable;

a mean value calculating unit for calculating the mean value of the temperature of the storage battery during charging, discharging or an idle state;

an elapsed time measuring unit for measuring the time elapsed after the installation of the storage battery,

a second diminution in lifetime calculating unit for calculating a second diminution in lifetime which decreases the expected lifetime value based on the mean value of the temperatures of the storage battery calculated by the mean value calculating unit, the ambient temperature measured by the ambient temperature measuring unit and the time elapsed measured by the elapsed time measuring unit; and

a remaining lifetime value calculating unit for calculating the remaining lifetime value by subtracting the first diminution in lifetime calculated by the first diminution in lifetime calculating unit and the second diminution in lifetime calculated by the second diminution in lifetime calculating unit from the expected lifetime value selected by the expected lifetime selecting unit.

2. The battery life predicting device according to claim 1, wherein the second diminution in lifetime calculating unit calculates the second diminution in lifetime by multiplying the value of an exponential function that takes the difference between the mean value of the storage battery temperatures calculated by the mean value calculating unit and the ambient temperature measured by the ambient temperature measuring unit as a variable by the elapsed time measured by the elapsed time measuring unit.

3. The battery life predicting device according to claim 1, further comprising an occasional expected lifetime value calculating unit for calculating an occasional expected lifetime value by multiplying the value of an exponential function that takes the difference between the ambient temperature measured by the ambient temperature measuring unit and the mean value of temperatures of the storage battery calculated by the mean value calculating unit as a variable by the value of expected lifetime value selected by the expected lifetime selecting unit, wherein

the remaining lifetime value calculating unit calculates the remaining lifetime value by subtracting the first diminution in lifetime calculated by the first diminution in lifetime calculating unit and the second diminution in lifetime calculated by the second diminution in lifetime calculating unit from the occasional expected lifetime value calculated by the occasional expected lifetime value calculating unit.

4. The battery life predicting device according to claim 1, further comprising a lifetime value storing unit for storing the remaining lifetime value calculated by the remaining lifetime value calculating unit, wherein

the remaining lifetime value calculating unit reads the value of the remaining lifetime value that has been calculated last and stored in the lifetime data storing unit, and calculates the latest value of the remaining lifetime value by subtracting the first diminution in lifetime and the second diminution in lifetime from the remaining lifetime value that has been read.

5. The battery life predicting device according to claim 1, wherein the storage battery includes a nickel-hydrogen storage battery.

6. The battery life predicting device according to claim 1, wherein the storage battery is installed integrally with various units of the battery life predicting device.

7. The battery life predicting device according to claim 1, further comprising a notifying unit for informing the user of the remaining lifetime value calculated by the remaining lifetime value calculating unit.

8. The battery life predicting device according to claim 1, further comprising a communication unit for sending the remaining lifetime value calculated by the remaining lifetime value calculating unit

9. The battery life predicting device according to claim 1, further comprising a charge control unit for controlling charging of the storage battery based on the remaining lifetime value calculated by the remaining lifetime value calculating unit.

10. A battery life predicting method comprising:

a load power measuring step for measuring the load power applied by a storage battery during discharge;

an ambient temperature measuring step for measuring the ambient temperature of the location where the storage battery is installed;

an expected lifetime value selecting step for selecting, as an expected lifetime value, a lifetime that corresponds to the load power measured in the load power measuring step and the ambient temperature measured in the ambient temperature measuring step while referring to the lifetime data that shows the relationship between the load power applied by the storage battery during discharge and the ambient temperature of the storage battery, and the lifetime of the storage battery;

a number of discharges counting step for counting the number of discharge cycles of the storage battery;

a first diminution in lifetime calculating step for calculating the first diminution in lifetime which decreases the expected lifetime value based on a natural logarithmic function that takes a value of time, obtained by converting the number of discharge cycles counted in the discharge cycles counting step, as a variable;

a mean value counting step for calculating the mean value of the temperatures of the storage battery during charging, discharging or an idle state;

an elapsed time measuring step for measuring the time elapsed after the installation of the storage battery;

a second diminution in lifetime calculating step for calculating the second diminution in lifetime which decreases the expected lifetime value based on the mean value of the storage battery temperatures calculated in the mean value counting step, the ambient temperature measured in the ambient temperature measuring step and the time elapsed measured in the elapsed time measuring step; and

a remaining lifetime value calculating step for calculating the remaining lifetime value by subtracting the first diminution in lifetime calculated in the first diminution in lifetime calculating step and the second diminution in lifetime calculated in the second diminution in lifetime calculating step from the expected lifetime value selected in the expected lifetime value selecting step.