JP2007110895A - Charging device of battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charging device of a battery that provides a function to display that what time charging is completed after the start of charging. <P>SOLUTION: A charging device includes battery temperature detecting means for detecting the temperature of a battery pack, a battery voltage detecting means for detecting a battery voltage of the battery pack, and a display means for displaying a required time until charging is completed at a plurality steps. The device further includes a first means for determining that the battery pack has come to a state immediatly before full charging from an output of the battery temperature detecting means or the battery voltage detecting means, and a second means for determining that the battery pack has reached full charging from the output of the battery temperature detecting means or the battery voltage detecting means. The display of the display means is taken as the shortest stage of a required charge time based on the result of the determination of the first means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a charging device for charging a secondary battery such as a nickel-cadmium battery or a nickel metal hydride battery.

  In general, a rechargeable battery is used as a power source for a portable device, and after being removed from the device and charged by a charging device, the operation of mounting and using the device again is repeated. At the time of this work, the user has a request that “I want to know how much time is required to complete charging at the start of charging”.

  In recent years, in order to meet this demand, as disclosed in Japanese Patent Application Laid-Open No. 2001-116812 (Patent Document 1), a microcomputer is built in the battery body, load current and usage time are integrated, and the integrated amount and the rated capacity of the battery are integrated. A battery with a battery charge amount display that displays the charge amount (remaining capacity) of the battery with an LED or the like has been proposed.

JP-A-2001-116812

  The battery with battery charge indication described above needs to incorporate a calculation means such as a microcomputer for performing an integration calculation of load current and usage time in the battery body. However, since not all batteries have such a built-in means, there is a problem that a battery that does not have a microcomputer built in the battery body cannot satisfy the above user's requirements.

  An object of the present invention is to realize a function of displaying how long charging is completed during charging of a battery in a charging device.

  In order to achieve the above object, the charging device of the present invention is a charging device for charging a battery pack in which a plurality of cells are connected in series, the battery temperature detecting means for detecting the temperature of the battery pack, and the battery pack battery In a charging device comprising a battery voltage detecting means for detecting a voltage and a display means for displaying a time required for completion of charging in a plurality of stages, the battery pack is detected by an output of the battery temperature detecting means or the battery voltage detecting means. First means for determining that the battery is about to be fully charged, and second means for determining that the battery pack has reached full charge based on the output of the battery temperature detecting means or the battery voltage detecting means. One feature is that the display on the display unit is displayed at the stage with the shortest required charging time according to the determination result of the first unit.

  Another feature of the present invention is that the first determination unit calculates a temperature gradient at a predetermined time interval based on an output of the temperature detection unit, and whether or not the temperature gradient has increased by a predetermined value or more. Therefore, the state immediately before full charge is determined.

  Another feature of the present invention is that the first determination means calculates a battery voltage gradient at a predetermined time interval based on the output of the battery voltage detection means, and whether or not the battery voltage gradient has increased by a predetermined value or more. Therefore, the state immediately before full charge is determined.

  Another feature of the present invention is that the first determination means calculates a temperature rise value of the battery pack being charged based on the output of the battery temperature detection means, and whether the temperature rise value has increased by a predetermined value or more. That is, the state immediately before the full charge is determined depending on whether or not.

  According to the present invention, it is possible to realize a display function as to whether or not the battery is nearly fully charged and whether or not the battery is fully charged after the charging is started.

  FIG. 1 is a block circuit diagram showing an embodiment of the present invention. In the figure, 1 is an AC power source, and 2 is a battery pack in which a plurality of rechargeable cells are connected in series. The battery pack 2 includes a battery set 2a in which a plurality of cells are connected in series, a temperature detection element 2b including, for example, a thermistor that detects battery temperature in contact with or close to the cells, and a number for determining the number of cells. Correspondingly, for example, a cell number discriminating element 2c in which a resistance value is set is incorporated.

  3 is a current detection circuit for detecting the charging current flowing through the battery pack 2, and 4 is an output voltage detection circuit comprising resistors 4a and 4b. The output voltage of the secondary side rectifying and smoothing circuit 30 of the power supply circuit is divided by the resistors 4a and 4b. And input to the output voltage control circuit 80. Reference numeral 5 denotes a signal transmission means for feeding back the output voltage of the secondary side rectifying / smoothing circuit 30 and the signal of the charging current to the SW control IC 23, and is composed of a photocoupler or the like. Reference numeral 6 denotes an output voltage setting circuit composed of resistors 6a and 6b. The voltage value set by the voltage dividing ratio of the resistors 6a and 6b becomes a reference voltage and is compared with the output voltage of the secondary side rectifying and smoothing circuit 30.

  A charging current setting circuit 7 includes resistors 7a, 7b, 7c, 7d, and 7e. The voltage divided by the resistors 7a and 7b is applied to the output port 56 of the microcomputer 50 via the resistors 7c, 7d, and 7e. The charging current is set by selecting one of the resistors 7c, 7d, and 7e (making the output port low level or high level).

  Reference numeral 8 denotes battery temperature detection means comprising resistors 8a and 8b. A divided voltage determined by a voltage dividing ratio between the resistors 8 a and 8 b and the temperature detection element 2 is input to the A / D converter 55 of the microcomputer 50. When the resistance value of the temperature detection element 2b changes according to the battery temperature, the voltage division ratio changes and is input to the A / D converter 55 of the microcomputer 50. Since the voltage changes, the temperature of the battery pack 2 can be detected from the voltage.

  Reference numeral 9 denotes a resistor constituting the cell number discriminating means, and 2c denotes a cell number discriminating element in which, for example, a resistance value is set according to the number of cells of the battery pack 2. The voltage Vcc is divided by the resistor 9 and the cell number discriminating element (resistor in this embodiment) 2c, and the divided voltage is input to the A / D converter 55 of the microcomputer 50. Since this voltage changes depending on the resistance value of the element 2c, the number of cells of the battery pack 2 can be determined from the voltage. Note that the determination of the number of cells can be detected, for example, by dividing the terminal voltage of the battery pack 2 by the voltage per unit cell, so the present invention is limited to the battery pack 2 with the cell number determination element 2c added. It is not a thing.

  Reference numeral 10 denotes a primary side rectifying / smoothing circuit comprising a full-wave rectifying circuit 11 and a smoothing capacitor 12. Reference numeral 20 denotes a switch circuit comprising a high-frequency transformer 21, a MOSFET 22, a SW control IC 23, a SW control IC constant voltage circuit 24, and a starting resistor 25. . The high-frequency transformer 21 includes a primary winding 21a, a secondary winding 21b, a tertiary winding 21c, and a quaternary winding 21d, and a DC input voltage is applied to the primary winding 21a. The secondary winding 21b is an output winding for the SW control IC, the tertiary winding 21c is an output winding for charging the battery set 2, and the secondary winding 21d is a power source for the microcomputer 50, the charging current control means 60, etc. Output winding for.

  In addition, with respect to the primary winding 21a, the secondary winding 21b and the fourth winding 21d have the same polarity, and the tertiary winding 21c has a reverse polarity. The SW control IC 23 is a switching power supply IC for adjusting the output voltage by changing the drive pulse width of the MOSFET 22. The SW control IC constant voltage circuit 24 is composed of a diode 24a, a three-terminal regulator 24b, and capacitors 24c and 24d, and makes the output voltage from the secondary winding 21b constant.

  Reference numeral 30 denotes a secondary side rectifying / smoothing circuit comprising a diode 31, a smoothing capacitor 32, and a resistor 33. Reference numeral 40 denotes a battery voltage detection circuit including resistors 41 and 42 that divides the terminal voltage of the battery pack 2. The divided voltage is input to the CPU 51 through the A / D converter 55. Reference numeral 50 denotes a microcomputer, which includes a calculation means (CPU) 51, a ROM 52, a RAM 53, a timer 54, an A / D converter 55, an output port 56, and a reset input port 57. The CPU 51 samples a signal entering the A / D converter 55 at a predetermined time interval and takes it into the microcomputer 50. Then, the current battery voltage and the battery temperature are compared with the battery voltage and the battery temperature before a plurality of samplings, and based on the result, the state of charge of the battery pack 2 is almost full or has reached full charge. It is determined whether or not. The RAM 53 stores a predetermined number of sampling values of battery voltage and battery temperature.

  A charging current control circuit 60 includes operational amplifiers 61 and 62, resistors 63 to 67, and a diode 68. The charging current detected by the charging current detection circuit 3 is added to the operational amplifier 61 and corresponds to this charging current. The voltage is inverted and amplified. The difference between the output voltage of the amplifier 61 and the charging current setting reference voltage set by the charging current setting circuit 7 is amplified by the operational amplifier 62 and fed back to the SW control IC 23 via the signal transmission means 5. The SW control IC 23 controls on / off of the MOSFET 22 to generate a pulse having a narrow pulse width when the charging current is large, and to generate a pulse having a wide pulse width when the charging current is large, and apply the pulse to the high-frequency transformer 21. Since this pulse is smoothed to a direct current by the rectifying and smoothing circuit 30 and applied to the battery pack 2, the charging current is controlled to be constant. That is, the current detection circuit 3, the charging current control circuit 60, the signal transmission means 5, the switching circuit 20, and the rectifying / smoothing circuit 30 are controlled so that the charging current of the battery pack 2 becomes a set current value set by the microcomputer 50.

  A constant voltage circuit 70 includes a diode 71, capacitors 72 and 73, a three-terminal regulator 74, and a reset IC 75. The output voltage of the constant voltage circuit 70 becomes a power source for the microcomputer 50, the charging current control means 60, and the like. The reset IC 75 outputs a reset signal to the reset input port 57 in order to put the microcomputer 50 into an initial state.

  An output voltage control circuit 80 includes an operational amplifier 81, resistors 82 to 85, and a diode 86. The difference between the voltage from the output voltage detection circuit 4 and the voltage from the output voltage setting circuit 6 is amplified by the operational amplifier 81 and fed back to the SW control IC 23 via the signal transmission means 5. As a result, the output voltage of the rectifying / smoothing circuit 30 is controlled.

  Reference numeral 90 denotes display means comprising LEDs 91 and 92 and resistors 93 to 96. The LEDs 91 and 92 are composed of, for example, a red light emitting diode R and a green light emitting diode G. Red and green lights by the output of the output port 56 of the microcomputer 50, and both colors emit light at the same time, thereby emitting orange light. Is also a possible type. In the present embodiment, the LED 91 displays the charging completion before and after charging in red and green, respectively, and the LED 92 is an LED that displays in three stages how long charging is completed during charging. Red, orange, and green are displayed from the stage determined to be long. These are summarized in Tables 1 and 2 below.

  Next, the control method of the charging device of the present invention will be described with reference to the circuit diagram of FIG. 1 and the flowcharts of FIGS. When the power is turned on, the microcomputer 50 enters a connection standby state for the battery pack 2. Connection of the battery pack 2 is determined by signals from the battery voltage detection means 40, the battery temperature detection means 8, and the cell number determination means 9 (step 201).

  When the battery pack 2 is connected, various flags stored in the RAM 53 are initially reset (step 202). The flag is for displaying the battery state. As shown in FIG. 4, the remaining battery capacity flag, the remaining battery capacity flag, the remaining battery capacity flag, the battery high temperature flag, and the LED 92 red lighting flag for displaying the battery discharge state, And ΔVFlag for full charge display by battery voltage detection.

  Next, the battery voltage V0 before the start of charging is detected by the battery voltage detecting means 40, and taken into the microcomputer 50 via the A / D converter 55 (step 203). Further, the output voltage of the cell number discriminating means 9 is taken into the microcomputer 50 via the A / D converter 55 and the cell number n of the battery pack 2 is discriminated (step 204). The resistance value of the cell number determination element 2c built in the battery pack 2 is set according to the number of cells, and the divided voltage between the cell number determination element 2c and the cell number determination means 9 varies depending on the number of cells. Thus, the number of cells of the battery pack 2 can be determined. Subsequently, the temperature T0 before the start of charging of the battery pack 2 is detected by the battery temperature detecting means 8 and taken into the microcomputer 50 in the same manner (step 205). The output voltage of the battery temperature detecting means 8 is determined by the voltage division ratio with the temperature detecting element 2b, and the resistance value of the temperature detecting element 2b changes according to the battery temperature. Therefore, the battery temperature is calculated from the output voltage of the battery temperature detecting means 8. Can be detected.

  Next, the microcomputer 50 calculates the cell voltage of the battery pack 2 from the pre-charging start voltage V0 and the number of cells n. The cell voltage is obtained by dividing the pre-charge start voltage V0 by the number of cells n. First, it is determined whether or not the cell voltage is 1.40 V / cell or more (step 206). When the cell voltage is 1.40 V / cell or more, it is determined that the battery pack 2 to be charged has a large remaining battery capacity, and the microcomputer 50 sets the large remaining battery flag Flag of the RAM 53 as the storage means to 1 ( Step 207) and jump to Step 211.

  In step 206, if the cell voltage is not 1.40V / cell or more, it is determined whether or not the cell voltage is 1.25V / cell or less (step 208), and the cell voltage is 1.25V / cell or less. In this case, it is determined that the battery pack 2 to be charged has a small remaining battery capacity, and the small battery remaining capacity flag of the RAM 53 which is the storage means of the microcomputer 50 is set to 1 (step 209). In step 208, if the cell voltage is not 1.25 V / cell or less, the battery pack 2 determines that the remaining capacity of the battery is in the middle, and the flag of the remaining battery capacity of the RAM 53, which is the storage means of the microcomputer 50, is set. 1 is set (step 210).

  Next, it is determined whether or not the battery temperature T0 before starting charging of the battery pack 2 is 40 ° C. or higher (step 211). If the battery temperature T0 before starting charging is 40 ° C. or higher, the battery high temperature flag is set to Then, it is set to 1 (step 213), and subsequently, it is determined whether or not the remaining battery capacity flag of the RAM 53 which is the storage means of the microcomputer 50 is 1 (step 214). When the remaining battery capacity flag is 1, the remaining battery capacity of the battery pack 2 to be charged is large, so it is determined that the time until completion of charging is short, and the microcomputer 50 turns on the LED 92 in green (step 215). Jump to 220.

  On the other hand, if the large remaining battery capacity flag is 0 in step 214, it is determined whether or not the remaining battery capacity flag is 1 (step 216). When the remaining battery capacity flag is 1, since the remaining capacity of the battery pack 2 to be charged is medium, the time until completion of charging is determined to be medium, and the microcomputer 50 lights the LED 92 in orange (step 217). ), Jump to step 220.

If the flag in the remaining battery capacity is not 1 in step 216, it is determined that the remaining capacity of the battery pack 2 is small, the LED 92 red lighting flag is set to 1 (step 218), and the LED 92 is lit red (step 219). . Subsequently, it is determined whether or not the battery high temperature flag of the RAM 53 that is the storage means of the microcomputer 50 is 1 (step 220). If the battery high temperature flag is 1, the battery pack 2 is determined to be high, and the battery pack Charging is started with a charging current I3 that can be handled in a high temperature state of 2 (step 221), and the process jumps to step 227.
In this embodiment, the charging current can be set in three stages of I1, I2, and I3, and I1>I2> I3.

  In step 220, when the battery high temperature flag is not 1, the battery pack 2 determines that the battery pack 2 is at a low temperature from the processing of step 212 described below, and is charged with a charging current I2 that can be handled in the low temperature state of the battery pack 2. Is started (step 222), and the process jumps to step 227.

  The charging current can be set to I3 by selecting the resistance 7c of the charging current setting means 7 to "L" level (the remaining 7d and 7e are high impedance "levels) by the microcomputer 50. This setting means. 7 is applied to the operational amplifier 62 and compared with the charging current flowing through the battery pack 2. The difference is fed back to the PWM control IC 23 via the signal transmission means 5. Since the pulse width of the MOSFET 22 is controlled, it is possible to control the charging current to be I3.

  The control of the charging current I2 is also the same. The charging current setting reference voltage V2 corresponding to the charging current I2 is set to the "L" level (the remaining 7c and 7e are set to high impedance). It can be set by selecting (Level).

  In step 211, if the battery temperature T0 before starting the charging of the battery pack 2 is not 40 ° C. or higher, it is determined whether or not the battery temperature T0 before starting the charging of the battery pack 2 is 5 ° C. or lower (step). 212) When the battery temperature T0 before the start of charging is 5 ° C. or lower, the processes of steps 214 to 222 described above are performed.

  In step 212, when the battery temperature T0 before the start of charging is not 5 ° C. or less, it is determined from the processing in steps 211 and 212 described above that the battery pack 2 is neither high nor low temperature, that is, the battery pack 2 is a temperature environment that can be rapidly charged. To do. That is, when the battery temperature is 40 ° C. or higher, charging is performed with the smallest charging current I3 (I3 <I2 <I1), and when the battery temperature is 5 ° C. or lower, charging is performed with the charging current I2, but the battery temperature T0 is 40 ° C.> When T0> 5 ° C., rapid charging is possible, so that charging can be performed with the largest charging current I1. Subsequent to step 212, it is determined whether or not the remaining battery capacity flag is 1 (step 223). If the remaining battery capacity flag is 1, it is determined that the time until completion of charging is short, and the LED 92 is turned on. Lights up green (step 224).

  In step 223, if the large remaining battery capacity flag is not 1, the remaining capacity of the battery pack 2 is medium or low, but since it is a temperature environment in which rapid charging can be performed with a large charging current, the time until charging is completed. Therefore, the LED 92 is lit in orange (step 225), and charging is started with the charging current I1 (I1> I2, I3) (step 226).

  The charging current I1 is obtained by selecting the resistances 7c, 7d and 7e of the charging current setting means 7 to a high level and setting the charging current setting reference voltage V1 corresponding to the charging current I1.

  After the start of charging, the microcomputer 50 starts time measurement from the start of charging using the timer 54 (step 227), and determines whether or not a predetermined time has elapsed from the start of charging (step 228). When the predetermined time has elapsed, it is determined whether or not the LED 92 red lighting flag is 1 (step 229). If this is 1, the time from when it is determined that the time until the battery is fully charged is long. It is determined that the time until completion has become medium, the LED 92 red lighting flag is set to 0 (step 230), and the LED 92 is lit orange (step 231).

  If it is determined in step 228 that the predetermined time has not elapsed since the start of charging, the process jumps to step 232. Similarly, if the LED 92 red lighting flag is not 1 in step 229, the process jumps to step 232.

  As described above, the present embodiment determines the remaining battery capacity from the cell voltage before starting charging, sets the charging current according to the temperature of the battery pack before starting charging or at the beginning of charging, and increases the remaining battery capacity. Then, the time until the completion of charging is predicted from the magnitude of the charging current and is divided into three stages, and the color is displayed according to the classification.

  Next, a process flow for determining whether or not the battery pack 2 is about to be fully charged and determining whether or not the battery pack 2 is fully charged will be described with reference to FIG. First, the latest battery temperature Tin is taken into the microcomputer 50 by the battery temperature detecting means 8 (step 232). Further, a value obtained by sampling the output signal of the battery temperature detecting means 8 every predetermined time is stored in the RAM 53 in advance, and the sampled battery temperature data during charging is compared to thereby obtain the minimum value Tmin of the battery temperature during charging. Is calculated and stored (step 233).

  Subsequently, the latest battery voltage Vin of the battery pack 2 is detected and taken in by the battery voltage detecting means 40 (step 234). The microcomputer 50 calculates the latest battery temperature gradient dT / dt at a predetermined sampling number interval from the battery temperature data during charging sampled based on the output of the battery temperature detecting means 8 (step 235). Further, by comparing the calculated latest battery temperature gradient dT / dt data, the minimum value dT / dt (min) of the battery temperature gradient dT / dt having a predetermined sampling width is calculated and stored (step 236).

  Further, the microcomputer 50 calculates the latest battery voltage gradient ΔV at a predetermined sampling number interval from the battery voltage data during charging based on the output of the battery voltage detecting means 40 (step 237), and the calculated battery voltage gradient. By comparing the ΔV data, the minimum value ΔVmin of the battery voltage gradient having a predetermined sampling width is calculated and stored (step 238).

  Next, the battery pack 2 is immediately before fully charged. Based on the processing data of steps 232 to 238, first, the latest battery voltage gradient ΔV is compared with the minimum value ΔVmin of the battery voltage gradient sampled and calculated during charging, and the latest battery voltage gradient ΔV is obtained up to now. It is determined whether or not the battery voltage gradient during charging is increased by a predetermined value R1 or more from the minimum value ΔVmin of the battery voltage gradient (step 239).

  When it is determined in step 239 that the battery pack 2 has risen by a predetermined value R1 or more, the battery pack 2 determines that it is about to be fully charged, and sets ΔVFlag of the RAM 53, which is the storage means of the microcomputer 50, to 1 (step 240). In this case, it is determined that the time until the charging is completed is short, and the microcomputer 50 turns on the LED 92 in green (step 241) and jumps to the processing of step 244.

  In step 239, if the latest battery voltage gradient ΔV has not risen by a predetermined value R1 or more than the minimum value ΔVmin of the battery voltage gradient during charging so far, the latest battery temperature gradient dT / dt continues. The battery temperature gradient minimum value dT / dt (min) sampled and calculated during charging is compared, and the latest battery temperature gradient dT / dt is the minimum value dT / dt of the battery temperature gradient during charging so far. It is determined whether or not a predetermined value Q1 or more has been increased from (min) (step 242). As shown in FIG. 5, when the battery pack 2 rises from the minimum value to a predetermined value Q1 or more, it is determined that the battery pack 2 is about to be fully charged, and it is determined that the time until charging is completed is short. Turn on (step 241), and jump to the process of step 244.

  In Step 242, when the latest battery temperature gradient dT / dt has not increased by a predetermined value Q1 or more from the minimum value dT / dt (min) of the battery temperature gradient during charging so far, Subsequently, the latest battery temperature Tin is compared with the minimum value Tmin of the battery temperature sampled and calculated during charging, and the latest battery temperature Tin is set in advance from the minimum value Tmin of the battery temperature during charging so far. It is determined whether or not the value has increased by a value P1 or more (step 243). As shown in FIG. 6, when the battery pack 2 has risen by a predetermined value P1 or more, it is determined that the battery pack 2 is about to be fully charged. The green light is turned on (step 241), and the process jumps to the process of step 244.

  Next, a full charge determination process for the battery pack 2 is performed. First, it is determined whether or not the latest battery temperature Tin has increased by a predetermined value P2 (P2> P1) or more from the minimum value Tmin of the battery temperature during charging so far (step 244). As shown, when the battery pack 2 rises by a predetermined value P2 or more, the battery pack 2 is determined to be fully charged. Then, the microcomputer 50 sets the charging current to a trickle current corresponding to a state similar to the stopped state. This setting can be set by selecting the ends of the resistors 7c, 7d, and 7e of the charging current setting means 7 at a low level. A current setting reference voltage corresponding to trickle charge is applied to the operational amplifier 62 to perform trickle charge on the battery pack 2 and the microcomputer 50 turns off the LED 92 (step 248), and then determines whether or not the battery pack 2 has been taken out. (Step 249). If the battery pack 2 is taken out, the process returns to Step 201 and waits for the next charging.

  In step 244, if the latest battery temperature Tin has not risen by more than a predetermined value P2 set in advance from the minimum value Tmin of the battery temperature that has been charged so far, the latest battery temperature gradient dT / dt, The minimum battery temperature gradient dT / dt (min) sampled and calculated during charging is compared, and the latest battery temperature gradient dT / dt is calculated as the minimum battery temperature gradient dT / dt ( min) to determine whether or not a predetermined value Q2 (Q2> Q1) or more has been set in advance (step 245), and if it has increased to a predetermined value Q2 or more, the battery pack 2 is determined to be fully charged, and is described above. Steps 248 and 249 are performed.

  In step 245, when the latest battery temperature gradient dT / dt has not increased by a predetermined value Q2 or more from the minimum value dT / dt (min) of the battery temperature gradient during charging so far, Subsequently, it is determined whether or not ΔVFlag of the RAM 53 which is the storage means of the microcomputer 50 is 1 (step 246). If ΔVFlag is not 1, it is determined that the battery pack 2 is not fully charged, and step 228 is performed. Return to the process.

  In step 246, if ΔVFlag is 1, it is determined whether or not the latest battery voltage gradient ΔV is equal to or lower than a predetermined value R2 (FIG. 7) (step 247). The battery pack 2 is determined to be fully charged, and the processes of steps 248 and 249 described above are performed. In step 247, if the latest battery voltage gradient ΔV is not less than or equal to a predetermined value R2 set in advance, the process returns to step 228.

  As described above, according to the present embodiment, after charging is started, it is determined whether or not the battery voltage Vin and Tin are about to be fully charged from the calculation signals of the battery voltage Vin and Tin. It is controlled to change the display.

  In the above-described embodiment, when performing full charge determination and full charge determination, compared with the battery temperature minimum value Tmin, the battery temperature gradient minimum value dT / dt (min), and the battery voltage gradient minimum value ΔVmin, The determination is made based on the result, but the present invention is not limited to this. For example, the determination may be made by comparing the latest data with a predetermined value set in advance.

  Moreover, in the said embodiment, although operation | movement of LED91 of the display means 90 was not mentioned, for example, LED91 lights up red before charge standby, and when it ends charge (it transfers to trickle charge), it uses green lighting. Is possible.

In this embodiment, control is performed to trickle charge (small current) after full charge. However, for example, the control system power supply is supplied from another power supply, and after the charge is completed, the main power supply is stopped and the charge current is reduced. You may stop it completely.
Needless to say, various modifications can be made without changing the basic concept of the present invention.

The block circuit diagram which shows one Embodiment of the charging device concerning this invention. The flowchart which shows one Embodiment of the control method of this invention charging device. The flowchart which shows one Embodiment of the control method of this invention charging device. Explanatory drawing of the flag used for the control method of this invention. Explanatory drawing of the charge control by this invention charging device. Explanatory drawing of the charge control by this invention charging device. Explanatory drawing of the charge control by this invention charging device.

Explanation of symbols

  2 is a battery pack, 7 is a charging current setting means, 8 is a battery temperature detecting means, 9 is a cell number determining means, 40 is a battery voltage detecting means, 50 is a microcomputer as a control means, 60 is a charging current control means, and 90 is It is a display means.

Claims (4)

  A charging device for charging a battery pack in which a plurality of cells are connected in series, the battery temperature detecting means for detecting the temperature of the battery pack, the battery voltage detecting means for detecting the battery voltage of the battery pack, In a charging device including display means for displaying a required time in a plurality of stages, a first determination is made based on the output of the battery temperature detecting means or the battery voltage detecting means that the battery pack is in a state of being fully charged. Means and second means for determining that the battery pack has reached full charge from the output of the battery temperature detection means or the battery voltage detection means, and according to the determination result of the first means, A charging device characterized in that the display on the display means is a display at the stage with the shortest required charging time.   2. The charging device according to claim 1, wherein the first determination unit calculates a temperature gradient at a predetermined time interval based on an output of the temperature detection unit, and whether the temperature gradient has increased by a predetermined value or more. A charging device, wherein a state immediately before full charge is determined based on whether or not the battery is fully charged.   2. The charging device according to claim 1, wherein the first determination unit calculates a battery voltage gradient at a predetermined time interval based on an output of the battery voltage detection unit, and whether the battery voltage gradient has increased by a predetermined value or more. A charging device, wherein a state immediately before full charge is determined based on whether or not the battery is fully charged.   2. The charging device according to claim 1, wherein the first determination unit calculates a temperature increase value of the battery pack being charged based on an output of the battery temperature detection unit, and the temperature increase value increases by a predetermined value or more. A charging device that determines a state immediately before full charge depending on whether or not the battery is fully charged.

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