Apparatus for detecting state of charge of battery

• US 20080094034A1
• Filed: 10/24/2007
• Published: 04/24/2008
• Est. Priority Date: 10/24/2006
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Takahashi, Shin, Asada, Tadatoshi
• Granted Patent: US 8,203,311 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: B60L 53/11 DC charging controlled by the charging station, e.g. mode 4
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: G01R 31/3832 without measurement of battery voltage
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H02J 7/163 with special means for initiating or limiting the excitation current
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

There is provided a battery condition detecting apparatus which comprises: means for detecting a discharging and charging current from the battery; means for detecting whether or not a negative acceleration of charging current changes in its sign from negative to zero during charging of the battery based on a result of detecting the discharge current; means for calculating an integrated charged capacity of the battery by integrating an instantaneous charging current during charging of the battery; means for controlling an alternator mounted in an automotive vehicle so as to control an output electric power generated by the alternator such that a discharging current from the battery is kept to be constant; and means for determining that the charge polarization is cancelled, if the integrated discharged capacity becomes to be equal to the integrated charged capacity.

Claims

1. A apparatus that detects a condition of a battery comprising:

means for detecting a discharging and charging current from the battery;

means for detecting whether or not a negative acceleration of charging current changes in sign from a negative value to zero during charging of the battery based on a result of detecting the discharge current;

means for calculating an integrated charged capacity of the battery by integrating a charging current until when the negative acceleration of the charging current changes in its sign from the negative value to zero during charging of the battery;

means for controlling the alternator mounted so as to control an output electric power generated by the alternator such that a discharging current from the battery is kept to be constant in time; and

means for determining that the charge polarization of the battery generated during charging of the battery is cancelled, when if the integrated discharged capacity comes to be equal to the integrated charged capacity estimated just before a start of discharging of the battery.

2. The apparatus according to claim 1, wherein

the alternator has means for controlling the generator so as to set a terminal voltage of the battery to be a target value of the output voltage of the battery, and

the means for controlling the alternator compares the detected value of the discharging current detected by the means for detecting a discharging and charging current from the battery with the target value of the discharging current of the battery, and adjusts the target value of the discharging current of the battery based on a result of the comparison.

3. The apparatus according to claim 1, wherein

the means for controlling the alternator further comprising:

means for calculating an output current of the alternator; and

means for controlling the alternator to adjust the output current of the alternator based on the output current of the alternator calculated by the means for calculating the output current of the alternator such that the detected value of the discharging current becomes to agree with the target value of the discharging current.

4. The apparatus according to claim 3, further comprising:

means for detecting the output current of the alternator,

wherein the means for controlling the alternator to adjust the output current of the alternator corrects the output current of the alternator based on the detected value of the output current of the alternator detected by the means for detecting the output current of the alternator.

5. The apparatus according to claim 1, wherein

the means for detecting a discharging and charging current from the battery, the means for detecting whether or not a negative acceleration of charging current changes in its sign from negative to zero, the means for calculating an integrated charged capacity of the battery, the means for controlling an alternator, and the means for determining that the charge polarization of the battery generated during charging of the battery is cancelled, are arranged near a terminal of the battery.

6. The apparatus according to claim 5, wherein

the means for detecting a discharging and charging current from the battery is constituted by an electric current sensor fixed to the terminals of the battery or the housing of the battery, and

the electric sensor has the means for detecting a discharging and charging current from the battery, the means for detecting whether or not a negative acceleration of charging current changes in its sign from negative to zero, the means for calculating an integrated charged capacity of the battery, the means for controlling an alternator, and the means for determining that the charge polarization of the battery generated during charging of the battery is cancelled.