Method and apparatus for battery charging with constant current, constant voltage, and pulsed charging

Abstract

A battery charging apparatus includes a voltage detecting circuit, a current detecting circuit, a charging circuit, and a charge control circuit. The voltage detecting circuit detects a battery voltage of the battery and accordingly outputs a signal. The current detecting circuit detects a battery current supplied to the battery and accordingly outputs a signal. The charging circuit executes a current supply control to perform the charging to the battery such that the battery voltage becomes equal to a voltage predetermined based on control signals and also that the charging current becomes equal to a current predetermined based on the control signals. The charge control circuit instructs the charging circuit with the control signals to set the battery voltage and the charge current in response to a voltage indicated by the signal from the voltage detecting circuit.

1 . A battery charging apparatus which charges a battery, comprising: 
 a voltage detecting circuit arranged and configured to detect a battery voltage of said battery and for outputting a signal in response to a detected battery voltage;    a current detecting circuit arranged and configured to detect a charging current supplied to said battery and for outputting a signal in response to a detected charging current;    a charging circuit arranged and configured to control said charging current such that said detected battery voltage increases to become substantially equal to a first pre-set voltage in response to a first input control signal and also such that [[a]] said detected charging current becomes substantially equal to a constant current predetermined in response to a second input control signal; and    a charge control circuit that instructs said charging circuit by said first and said second input control signals to set said first pre-set voltage and said constant current in response to said signal from said voltage detecting circuit.    
     
     
         2 . The battery charging apparatus as defined in  claim 1 , wherein the charge control circuit is arranged and configured to instruct the charging circuit to perform [[a]] constant current charging to flow a first constant current to the battery and subsequently to flow a second constant current greater than the first constant current to the battery when the detected battery voltage of the battery is smaller than a second pre-set voltage, and to instruct the charging circuit to perform pulse charging, in which flowing current to said battery and pausing current flow to said battery are alternately performed at intervals of a pre-determined time period.  
     
     
         3 . The battery charging apparatus as defined in  claim 2 , wherein the charge control circuit instructs the charging circuit to control the charging current flowing to the battery such that a charging voltage applied across said battery becomes substantially equal to a third constant voltage during the constant current charging during the pulse charging and also such that the charging voltage becomes substantially equal to a first constant voltage smaller than the third constant voltage during the pausing in the pulse charging.  
     
     
         4 . The battery charging apparatus as defined in  claim 3 , wherein the charge control circuit instructs the charging circuit to perform the constant current charging to supply the second constant current to the second battery when the battery voltage becomes substantially equal to a third pre-set voltage greater than the second pre-set voltage and also to perform constant voltage charging to control the charging current such that the charging voltage becomes substantially equal to the third constant voltage when the battery voltage becomes substantially equal to a fourth pre-set voltage greater than the third pre-set voltage.  
     
     
         5 . The battery charging apparatus as defined in  claim 3 , wherein the charge control circuit instructs the charging circuit to control the charging current flowing through the battery such that the charging voltage becomes substantially equal to the third constant voltage during the constant current charging before the pulse charging is executed.  
     
     
         6 - 8 . (canceled)  
     
     
         9 . The battery charging apparatus as defined in  claim 2 , further comprising a charge-end detecting circuit that determines an event that indicates a charging is completed relative to the battery and outputs a predetermined signal when the charging current detected by the current detecting circuit becomes lower than the first constant current, and wherein the charge control circuit causes the charging circuit to stop the charging upon receiving the signal indicative of a charge end output from the charge-end detecting circuit.  
     
     
         10 . The battery charging apparatus as defined in  claim 3 , wherein the first constant voltage is a voltage greater than an over discharge voltage of the battery and the third constant voltage is a voltage substantially equal to a full charge voltage of the battery.  
     
     
         11 - 12 . (canceled)  
     
     
         13 . The battery charging apparatus as defined in  claim 1 , wherein the battery is a nonaqueous battery.  
     
     
         14 . The battery charging apparatus as defined in  claim 1 , wherein the battery is a lithium ion battery.  
     
     
         15 . A charging method for a battery, comprising the steps of: 
 first performing a first constant current charging by supplying a first constant current to the battery when a battery voltage of the battery is smaller than a first pre-set voltage;    second performing a second constant current charging by supplying a second constant current greater than the first constant current to the battery when the battery voltage of the battery is greater than the first pre-set voltage; and    operating a pulse charging of the battery when the battery voltage of the battery increases to be equal to or greater than a second pre-set voltage greater than the first pre-set voltage by alternately carrying out, at intervals of a predetermined time period, a constant current charging in which the second constant current is supplied to the battery and a pausing in which the supply of the constant current charging is stopped.    
     
     
         16 . The charging method as defined in  claim 15 , wherein the operating step comprises controlling a charging current to the battery such that a charging voltage of the battery becomes substantially equal to a third constant voltage during the constant current charging of the pulse charging and such that the charging voltage of the battery becomes substantially equal to a first constant voltage smaller than the third constant voltage during the pausing of the pulse charging.  
     
     
         17 . The charging method as defined in  claim 16 , further comprising steps of first executing a constant current charging in which the constant current charging with the second constant current is performed to the battery when the battery voltage of the battery becomes substantially equal to the third pre-set voltage greater than the second pre-set voltage and second executing a constant voltage charging in which the charging current is controlled such that the charging voltage of the battery becomes substantially equal to the third constant voltage when the battery voltage of the battery becomes substantially equal to a fourth pre-set voltage greater than the third pre-set voltage.  
     
     
         18 . The charging method as defined in  claim 16 , wherein the charging current to the battery is controlled such that the charging voltage of the battery becomes substantially equal to the third constant voltage during the first and second constant current charging.  
     
     
         19 . (canceled)  
     
     
         20 . The charging method as defined in  claim 15 , further comprising steps of determining that the charging is completed when the charging current to the battery becomes substantially equal to a predetermined current value smaller than the first constant current and subsequently terminating the charging to the battery.  
     
     
         21 . The charging method as defined in  claim 15 , wherein the battery is a nonaqueous battery.  
     
     
         22 . The charging method as defined in  claim 15 , wherein the battery is a lithium ion battery.  
     
     
         23 . A battery charging apparatus which charges a battery, comprising: 
 a voltage detecting circuit arranged and configured to detect a battery voltage of said battery and for outputting a signal in response to a detected battery voltage;    a current detecting circuit arranged and configured to detect a charging current supplied to said battery and for outputting a signal in response to a detected charging current;    a charging circuit arranged and configured to control said charging current such that said detected battery voltage increases to become substantially equal to a first pre-set voltage in response to an input control signal and also such that said detected charging current becomes substantially equal to a constant current predetermined in response to the input control signal; and    a charge control circuit that instructs said charging circuit by the input control signal to set said first pre-set voltage and said constant current in response to said signal from said voltage detecting circuit.    
     
     
         24 . The battery charging apparatus as defined in  claim 23 , wherein the charge control circuit is arranged and configured to instruct the charging circuit to perform constant current charging to flow a first constant current to the battery and subsequently to flow a second constant current greater than the first constant current to the battery when the detected battery voltage of the battery is smaller than a second pre-set voltage, and to instruct the charging circuit to perform pulse charging, in which flowing current to said battery and pausing current flow to said battery are alternately performed at intervals of a pre-determined time period.  
     
     
         25 . The battery charging apparatus as defined in  claim 24 , wherein the charge control circuit instructs the charging circuit to control the charging current flowing to the battery such that a charging voltage applied across said battery becomes substantially equal to a third constant voltage during the constant current charging during the pulse charging and also such that the charging voltage becomes substantially equal to a first constant voltage smaller than the third constant voltage during the pausing in the pulse charging.  
     
     
         26 . The battery charging apparatus as defined in  claim 25 , wherein the charge control circuit instructs the charging circuit to perform the constant current charging to supply the second constant current to the battery when the battery voltage becomes substantially equal to a third pre-set voltage greater than the second pre-set voltage and also to perform constant voltage charging to control the charging current such that the charging voltage becomes substantially equal to the third constant voltage when the battery voltage becomes substantially equal to a fourth pre-set voltage greater than the third pre-set voltage.  
     
     
         27 . The battery charging apparatus as defined in  claim 25 , wherein the charge control circuit instructs the charging circuit to control the charging current flowing through the battery such that the charging voltage becomes substantially equal to the third constant voltage during the constant current charging before the pulse charging is executed.  
     
     
         28 - 31 . (canceled)  
     
     
         32 . The battery charging apparatus as defined in  claim 25 , wherein the first constant voltage is a voltage greater than an over discharge voltage of the battery and the third constant voltage is a voltage substantially equal to a full charge voltage of the battery.  
     
     
         33 . The battery charging apparatus as defined in claim  28 , wherein the current detecting circuit comprises: 
 a resistor through which the charging current to be supplied to the battery flows; and    a current detector that detects the charging current based on a voltage across the resistor and outputs a signal in response to the detected charging current,    wherein the voltage detecting circuit, the current detector of the current detecting circuit, the charge control circuit, a charge-end detecting circuit, and several components of the charging circuit including a constant voltage generating circuit, a voltage switching circuit, a constant current reference signal generating circuit, a signal switching circuit, and a control circuit are integrated into a single integrated circuit chip.    
     
     
         34 . The battery charging apparatus as defined in claim  30 , wherein the current detecting circuit comprises: 
 a resistor through which the charging current to be supplied to the battery flows; and    a current detector that detects the charging current based on a voltage across the resistor and outputs a signal in response to the detected charging current,    wherein the voltage detecting circuit, the current detector of the current detecting circuit, the charge control circuit, a charge-end detecting circuit, and several components of the charging circuit including a constant voltage generating circuit, a voltage switching circuit, a constant current reference signal generating circuit, a signal switching circuit, and a control circuit are integrated into a single integrated circuit chip.    
     
     
         35 . The battery charging apparatus as defined in  claim 23 , wherein the battery is a nonaqueous battery.  
     
     
         36 . The battery charging apparatus as defined in  claim 23 , wherein the battery is a lithium ion battery.