Battery remaining capacity detection method and power supply apparatus

• US 20060158155A1
• Filed: 01/10/2006
• Published: 07/20/2006
• Est. Priority Date: 01/14/2005
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Tamezane, Shigeto, Matsumoto, Kenshi
• Granted Patent: US 7,471,067 B2
• Time in Patent Office: Days
• US Class Current: 320/132
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables

Abstract

A battery remaining capacity detection method calculates a remaining capacity of a battery having the possibility that a memory effect occurs by using correlation between an voltage V₀ and the remaining capacity. Correlation between a reset voltage V_{o reset} that is obtained by subtracting a value obtained by multiplying an occurrence amount V_m based on the memory effect by a memory effect occurrence amount correction value C(SOC) from an initial voltage V_{o ini} and the remaining capacity is obtained, in the battery after use, based on correlation between the initial voltage V_{o ini} and the remaining capacity. The remaining capacity is obtained by setting the voltage V₀ of the battery after use as the reset voltage V_{0 reset}. This method provides precise battery detection without completely discharging.

Claims

1. A battery remaining capacity detection method that calculates a remaining capacity of a battery having the possibility that a memory effect occurs by using correlation between an voltage V₀ and the remaining capacity comprising steps of:

obtaining correlation between a reset voltage V_{o reset} that is obtained by subtracting a value obtained by multiplying an occurrence amount V_m based on the memory effect by a memory effect occurrence amount correction value C(SOC) from an initial voltage V_{o ini} and the remaining capacity, in the battery after use, based on correlation between the initial voltage V_{o ini} and the remaining capacity;

obtaining the remaining capacity by setting the voltage V₀ of the battery after use as the reset voltage V_{0 reset}.

2. The battery remaining capacity detection method according to claim 1, wherein the memory effect occurrence amount correction value C(SOC) is a value that correlates to a remaining capacity used in a battery operation state before calculation.

3. The battery remaining capacity detection method according to claim 2, wherein the memory effect occurrence amount correction value C(SOC) is controlled such that, in the case where the remaining capacity used in the battery operation state falls within a range where the memory effect is large, it approaches 1, and, in the case where the remaining capacity used in the battery operation state falls within a range where the memory effect is small, it approaches zero.

4. The battery remaining capacity detection method according to claim 1, wherein the occurrence amount V_m based on the memory effect has a positive correlation with a value obtained by integrating a value obtained by multiplying a charging or discharging current value, a correction coefficient relating to battery deterioration, and a correction coefficient corresponding to a battery temperature at a prescribed period, wherein the correction coefficient corresponding to a battery temperature has a positive correlation with the battery temperature, wherein the correction coefficient relating to battery deterioration is a value that has a positive correlation with a value obtained by integrating a value obtained by multiplying a charging or discharging current value, and a correction coefficient corresponding to a second battery temperature at a prescribed period, wherein the correction coefficient corresponding to a second battery temperature has a positive correlation with the battery temperature.

5. The battery remaining capacity detection method according to claim 1, wherein a value obtained by multiplying the occurrence amount V_m based on the memory effect in the electromotive V₀ and the memory effect occurrence amount correction value C(SOC) is compared with a voltage reduction difference V_ms corresponding to a self discharging amount in the electromotive V₀, when the voltage reduction difference V_ms corresponding to a self discharging amount is larger, correlation between a second rest voltage V_{o reset} obtained by subtracting the voltage reduction difference V_ms corresponding to a self discharging amount from the initial voltage V_{o ini} and the remaining capacity is obtained, in the battery after use, based on correlation between the initial voltage V_{o ini} and the remaining capacity, and the remaining capacity is obtained by setting the voltage V_o of the battery after use as the second rest voltage V_{o reset}.

6. A battery remaining capacity detection method that detects a battery remaining capacity when power is supplied from a battery contained in a power supply apparatus to a connection device that is connected to the power supply apparatus comprising steps of:

detecting an integrated remaining capacity by detecting and integrating a charging/discharging current and/or a charging/discharging voltage applied to the connection device in operation of the connection device;

calculating a battery internal resistance and an initial voltage from the discharging current and the discharging voltage by detecting the discharging current, the discharging voltage and a battery temperature by repeating pulse discharging a plurality of times not in operation of the connection device;

estimating the battery remaining capacity based on the calculated battery internal resistance and initial voltage, and the detected battery temperature by referring to a previously prepared voltage table of initial voltage V_{o ini} or reset initial voltage V_{o reset}.

7. The battery remaining capacity detection method according to claim 6, wherein the method further comprising a step of correcting the integrated remaining capacity based on the estimated remaining capacity.

8. The battery remaining capacity detection method according to claim 6, wherein filtering is performed in calculation of the battery internal resistance and the initial voltage by repeating pulse discharging a plurality of times.

9. The battery remaining capacity detection method according to claim 6, wherein the connection device is a motor for a vehicle, and the remaining capacity of the battery included in the power supply apparatus that drives the motor for a vehicle is detected.

10. A power supply unit comprising:

a battery unit including a plurality of rechargeable batteries;

a voltage detection portion that detects a voltage of the rechargeable batteries included the battery unit;

a temperature detection portion that detects a temperature of the rechargeable batteries included the battery unit;

a current detection portion that detects a current applied to the rechargeable batteries included the battery unit;

a remaining capacity calculation portion that detects the remaining capacity of the rechargeable batteries based on calculation performed on signals input from the voltage, temperature and current detection portions; and

a communication processing portion that transmits the remaining capacity calculated by the remaining capacity calculation portion to a connection device, wherein

in operation of the connection device, the voltage detection portion and/or the current detection portion detects the charging/discharging voltage and/or the charging/discharging current applied to the connection device, and the remaining capacity calculation portion integrates the charging/discharging current and/or the charging/discharging voltage and thus detects an integrated remaining capacity, and

not in operation of the connection device, the remaining capacity calculation portion repeats pulse discharging a plurality of times, calculates a battery internal resistance and an initial voltage from the discharging current and/or the discharging voltage that is detected by the voltage detection portion and/or the current detection portion, wherein

the remaining capacity calculation portion estimates the remaining capacity of the battery based on the calculated battery internal resistance and initial voltage by referring to a previously prepared voltage table.

11. The power supply apparatus according to claim 10, wherein the integrated remaining capacity is further corrected based on the estimated remaining capacity.

12. The power supply apparatus according to claim 10, wherein filtering is performed in calculation of the battery internal resistance and the initial voltage by repeating pulse discharging a plurality of times.

13. The power supply apparatus according to claim 10, wherein the connection device is a motor for a vehicle, and the remaining capacity of battery included in the power supply apparatus that drives the motor for a vehicle is detected.