Battery remaining capacity detection method and power supply apparatus

• US 7,471,067 B2
• Filed: 01/10/2006
• Issued: 12/30/2008
• Est. Priority Date: 01/14/2005
• Status: Expired due to Fees

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Tamezane, Shigeto, Matsumoto, Kenshi
• Primary Examiner(s): Ullah; Akm E
• Assistant Examiner(s): TORRES RUIZ, JOHALI ALEJANDRA
• Application Number:
  US11/328,308
• Publication Number:
  US 20060158155A1
• Time in Patent Office: 1,085 Days
• Field of Search: 320/129, 320/132, 320/149, 320/130, 320/135
• 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 a correlation between a voltage (V₀) and the remaining capacity, the method comprising:

obtaining a 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 a correlation between the initial voltage (V_{o ini}) and the remaining capacity; and

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, a correlation between a second reset 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 the 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}).