JP4182543B2 - Charger - Google Patents

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.

  When charging a battery pack such as a nickel cadmium battery or nickel metal hydride battery used for power supplies such as cordless tools, it can be charged in a short time if it is charged with a large charging current, but the battery inside the battery pack generates a large amount of heat during charging. Thus, since the cycle life of the battery is shortened, a charging device has been proposed that charges over time with a small charging current so as to suppress the heat generation of the battery.

  On the other hand, a charging device that charges a battery pack while cooling the battery pack with a cooling fan provided in the charging device and suppresses heat generation of the battery in the battery pack at the time of charging with a large charging current has also been proposed. .

  The charging methods of the above two charging devices differ depending on whether or not the battery pack can cope with forced cooling, that is, whether or not the battery pack is provided with a structure such as an air hole for blowing air from the cooling fan. In this way, considering that the charging method is different between the cooling-compatible battery pack and the non-cooling-compatible battery pack, it is determined whether or not the battery temperature gradient at the start of charging is greater than or equal to a predetermined value. A charging method has been proposed in which the presence or absence of a cooling effect by blowing air to the battery pack is determined and charging is performed by determining an average charging current based on the result (see, for example, Patent Document 1).

  Further, as a method for determining whether the battery pack is fully charged, when the battery temperature gradient calculated with a certain sampling width rises more than a predetermined value from the minimum value in the battery temperature gradient storage means, ΔT / A Δt detection method and the like have been proposed (see, for example, Patent Document 2).

JP 2000-31440 A (Claim 6) JP-A-6-113475 (Claim 1)

  However, it is impossible to determine whether or not there is a cooling effect by simply using a battery temperature gradient calculated with a sampling width used for determining full charge in the ΔT / Δt detection method.

  This will be described with reference to FIGS. FIG. 1 and FIG. 2 show the battery temperature gradient (A / D conversion value) of the first sampling width used to determine the charging voltage, charging current, and full charge when charging the cooling-compatible battery pack and the non-cooling-compatible battery pack. ), A graph showing the transition of the battery temperature gradient (A / D conversion value) of the second sampling width (> first sampling width) used for determining the presence or absence of the cooling effect, the battery temperature K described on the horizontal axis is The time when the battery temperature reaches the predetermined value K is indicated. The minimum battery temperature gradient value until the predetermined battery temperature K is reached is small in the battery temperature gradient of the first sampling width between the cooling-compatible battery pack and the non-cooling compatible battery pack, and the battery temperature gradient of the second sampling width is There is a big difference between a battery pack that supports cooling and a battery pack that does not support cooling. As described above, it is difficult to determine whether or not there is a cooling effect using a battery temperature gradient that is simply calculated using a sampling width that is used to determine full charge in the ΔT / Δt detection method. If full charge is detected by the battery temperature gradient value of the second sampling width, full charge detection may be delayed and overcharge may occur.

  In addition, since the battery temperature gradient from the start of charging differs depending on the battery temperature at the start of charging, the charging current is determined simply by determining whether the battery temperature gradient at the start of charging is greater than or less than a predetermined value and whether there is a cooling effect. It is impossible.

  An object of the present invention is to provide a charging device that eliminates the drawbacks of the above-described prior art and can accurately determine whether the battery pack is compatible with cooling or not.

  According to the first aspect of the present invention, it is possible to determine whether or not the cooling fan has a cooling effect by determining whether or not the battery temperature gradient minimum value when the battery temperature reaches a predetermined temperature is greater than a preset first predetermined value. The objective can be achieved.

  The invention of claim 2 is characterized in that a first predetermined value for determining the presence or absence of the cooling effect is set corresponding to the battery temperature at the start of charging.

  As described above, according to the present invention, it is possible to accurately and reliably determine whether the battery pack is a cooling-compatible battery pack or a non-cooling-compatible battery pack, and as a result, charging can be performed with an accurate charging current.

  FIG. 3 is a block circuit diagram showing an embodiment of the charging device of the present invention. Reference numeral 1 denotes an AC power source, 2 denotes a battery pack, and includes a battery set in which a plurality of batteries 2a are connected in series and a temperature sensing element 2b including, for example, a thermistor that detects the battery temperature in contact with or close to the battery 2a. 3 is a current detection means for detecting the charging current flowing in the battery pack 2, 4 is a charge control signal transmission means for transmitting a signal for controlling the start and stop of charging, and 5 is a charge for feeding back a charge current signal to the PWM control IC 23. In the current signal transmission means, the charging control transmission signal means 4 and the charging current signal transmission means 5 are made of a photocoupler or the like. Reference numeral 6 denotes a cooling fan that cools the battery pack 2, and 7 denotes a driving unit that drives the cooling fan 6. The driving unit includes a transistor 7 a and resistors 7 b and 7 c. To control. Reference numeral 10 denotes a rectifying / smoothing circuit comprising a full-wave rectifying circuit 11 and a smoothing capacitor 12, 20 is a switching circuit comprising a high-frequency transformer 21, a MOSFET 22 and a PWM control IC 23, and the PWM control IC 23 changes the drive pulse width of the MOSFET 22 to provide a rectifying / smoothing circuit. 30 is a switching power supply IC that adjusts the output voltage of 30. A rectifying / smoothing circuit 30 includes diodes 31 and 32, a choke coil 33, and a smoothing capacitor 34. A battery voltage detecting unit 40 includes resistors 41 and 42, and divides the terminal voltage of the battery pack 2. Reference numeral 50 denotes a microcomputer comprising a calculation means (CPU) 51, a ROM 52, a RAM 53, a timer 54, an A / D converter 55, output ports 56a and 56b, and a reset input port 57. The CPU 51 calculates a plurality of battery temperature gradients at predetermined intervals from the latest battery temperature and the battery temperatures sampled before a plurality of sampling times, and calculates the current battery temperature gradient and the minimum battery temperature gradient stored in the RAM 53. Compare. The RAM 53 stores a battery temperature storage unit 531 for storing a battery temperature sampled before a predetermined sampling time, and a plurality of battery temperature gradients calculated at predetermined intervals from the latest battery temperature and the battery temperatures sampled before a plurality of sampling times. The battery temperature gradient storage means 532 is stored. 60 is a charging current control means comprising operational amplifiers 61 and 62 and resistors 63 to 66, 70 is a constant voltage comprising a power transformer 71, a full-wave rectifier circuit 72, three-terminal regulators 73 and 74, smoothing capacitors 75 to 77, and a reset IC 78. The power source is a power source for the cooling fan 6, the microcomputer 50, the charging current control means 60, and the like. The reset IC 78 outputs a reset signal to the reset input port 57 in order to bring the microcomputer 50 into an initial state. Reference numeral 80 denotes charging current setting means for setting a charging current, which changes a voltage value applied to the inverting input terminal of the operational amplifier 62 in response to a signal from the output port 56a. A battery temperature detection circuit 90 includes resistors 91 and 92 that convert the resistance value of the temperature sensing element 2 b of the battery pack 2 into a voltage and output the voltage to the A / D converter 55.

  According to the graph of FIG. 4, the cooling fan 6 determines whether or not the minimum value of the battery temperature gradient of the second sampling width when the battery temperature during charging reaches the predetermined temperature K is greater than a preset first predetermined value. A method for determining the presence or absence of the cooling effect will be described.

  FIG. 4 shows whether the cooling effect is present or not when the battery temperature during charging reaches a predetermined temperature K depending on whether or not the minimum battery temperature gradient until the battery temperature K is reached is greater than a preset first predetermined value. It is an example of the graph which shows the judgment standard which defined the 1st predetermined value which discriminate | determines the presence or absence of a cooling effect based on the battery temperature at the time of charge start. The horizontal axis indicates the battery temperature at the start of charging, the vertical axis indicates the minimum battery temperature gradient (A / D converted value) until reaching the predetermined temperature K, and the points in the figure indicate the cooling-compatible battery pack and the cooling An example of the minimum battery temperature gradient when the non-compliant battery pack is charged by changing the ambient temperature and the battery temperature at the start of charging is shown.

  As shown in FIG. 4, when the battery temperature at the start of charging is low, the minimum battery temperature gradient when the predetermined temperature K is reached is large, and conversely, when the battery temperature at the start of charging is high, the minimum battery temperature gradient is small. Also, if the battery temperature at the start of charging is the same, if the battery pack that supports cooling is charged at a low ambient temperature, the minimum battery temperature gradient is small, and conversely, if the battery pack that does not support cooling is charged, the battery pack that supports cooling The minimum battery temperature gradient is higher than when charging the battery. When the ambient temperature is high, the minimum battery temperature gradient value is the same as when the cooling battery is charged with a low ambient temperature, regardless of whether the battery pack is either a cooling-compatible battery pack or a non-cooling-compatible battery pack. Greater than minimum battery temperature gradient. From this, if it is determined that there is a cooling effect when the ambient temperature with a small minimum battery temperature gradient is low, the first predetermined value for determining whether there is a cooling effect corresponding to each battery temperature at the start of each charge is shown in FIG. It can be set on the boundary line as shown.

  From the above, when the predetermined temperature K is reached, based on the battery temperature at the start of charging, if there is a minimum battery temperature gradient in the area above the straight line in FIG. If there is a minimum battery temperature gradient in the region, it is determined that there is a cooling effect, and the charging current can be controlled.

  Next, a method for determining the presence or absence of the cooling effect based on whether or not the battery temperature gradient when the battery temperature gradient of the second sampling width is first calculated is greater than a predetermined second predetermined value will be described.

  The battery temperature gradient immediately after the battery temperature gradient of the second sampling width used when determining whether or not there is a cooling effect by this method is the second sampling when the battery temperature during charging reaches a predetermined temperature. The same tendency as the minimum value of the battery temperature gradient of the second sampling width used in the method of determining the presence or absence of the cooling effect depending on whether or not the minimum value of the battery temperature gradient of the width is larger than the first predetermined value set in advance. Show. That is, when the battery temperature is low, the battery temperature gradient immediately after the battery temperature gradient is calculated is large. Conversely, when the battery temperature at the start of charging is high, the battery temperature gradient immediately after the calculation is small. In addition, when the battery temperature at the start of charging is the same, if the battery pack for cooling is charged with the ambient temperature being low, the battery temperature gradient immediately after the calculation is small, and the battery pack that does not support cooling is charged The battery temperature gradient immediately after the calculation is higher than when the cooling battery pack is charged. When the ambient temperature is high, the battery temperature gradient immediately after the calculation is performed regardless of whether the battery pack is either a cooling-compatible battery pack or a non-cooling-compatible battery pack. Is larger than the battery temperature gradient immediately after the calculation. As described above, the second predetermined value for determining the presence or absence of the cooling effect for each battery temperature at the start of each charge can be set on a certain boundary line as in FIG. Based on the above, based on the battery temperature at the start of charging, if there is a battery temperature gradient immediately after being calculated in the area above the boundary line, it is determined that there is no cooling effect, and conversely it is calculated in the lower area. If there is a battery temperature gradient immediately after, it is determined that there is a cooling effect, and the charging current can be controlled.

  Next, referring to the block circuit diagram of FIG. 3 and the flowcharts of FIGS. 5 and 6, a first predetermined battery temperature gradient minimum value when the battery temperature during charging reaches a predetermined temperature K in the present invention is preset. The operation in the case where the presence or absence of the cooling effect is determined based on whether or not the value is greater than the value will be described.

  When the power is turned on, the microcomputer 50 initially sets the output ports 56a and 56b, and enters the connection standby state of the battery pack 2 (step 501). When the battery pack 2 is connected, the cooling fan 6 operates (step 502), and then charging is started with the charging current I0 (step 503).

  The battery temperature Ti-36, Ti-35,..., Ti-01 before the sampling of the storage data of the battery temperature storage means 531 and the latest battery temperature of the storage data of the battery temperature gradient storage means 532 and 12 samplings. Temperature gradient minimum value dT / dt (MIN12) of the first sampling width calculated from the previous battery temperature and battery temperature gradient minimum value of the second sampling width calculated from the latest battery temperature and the battery temperature before 36 sampling dT / dt (MIN 36), a cooling effect present flag, a cooling effect absent flag, and a 45 ° C. flag are initially set (step 504), and a sampling timer is started (step 505). When the sampling timer time Δt has elapsed (step 506), the sampling timer is started again (step 507). In this example, the sampling timer time Δt is 5 seconds. The battery temperature gradient of the first sampling width is a value obtained by dividing the subtraction result of the latest battery temperature and the battery temperature before 12 sampling by the time of 60 seconds for 12 sampling, and the battery temperature gradient of the second sampling width is the latest battery temperature. A value obtained by dividing the subtraction result between the temperature and the battery temperature gradient before 36 sampling by the time of 36 samplings by 180 seconds.

Next, the divided voltage value obtained by dividing the battery temperature Tin by the battery temperature detecting means 90 by the resistors 91 and 92 is A / D converted by the A / D converter 55 and taken in as the battery temperature (step 508). At this time, when the sampling timer is started for the first time (step 509), the captured battery temperature Tin is stored in the battery temperature storage means 531 as the battery temperature T0 at the start of charging (step 510). Next, the battery temperature Ti-36 before 36 sampling of the stored data of the battery temperature storage means 531 is subtracted from the previously acquired battery temperature Tin, and the value is divided by 36 sampling times 180 seconds, and the value (Tin -Ti-36) / 180 is stored in the battery temperature gradient storage means 532 as the battery temperature gradient dT / dt (in 36) of the second sampling width (step 511). Whether the battery temperature gradient dT / dt (in 36) of the second sampling width is positive or negative is compared (step 512). If it is not negative, the time of 180 seconds or more has elapsed for 36 sampling times, and the battery temperature of the second sampling width since the calculation of the gradient is started, it compares the battery temperature gradient dT / dt of the second sampling interval (in36) and the battery temperature of the second sampling interval gradient minimum value dT / dt (MIN36) (step 513 ), When the battery temperature gradient dT / dt (in36) of the second sampling width is smaller than the battery temperature gradient minimum value dT / dt (MIN36) of the second sampling width, the battery temperature gradient minimum value dT / of the second sampling width dt (MIN36) is updated (step 514), and the battery temperature gradient dT / dt (in36) of the second sampling width is If not greater than the minimum value of temperature dT / dt gradient (MIN36) skips step 514. In step 512, when the battery temperature gradient dT / dt (in 36) of the second sampling width is negative, the calculation for the battery temperature gradient of the second sampling width is not started since the time for 36 samplings has not exceeded 180 seconds. Therefore, step 513 and step 514 are skipped.

Next, the battery temperature Ti-12 before 12 sampling is subtracted from the battery temperature Tin previously taken in, and the value is divided by the time of 60 seconds corresponding to 12 samplings, and the value (Tin-Ti-12) / 60 is divided into The electric temperature gradient dT / dt (in 12) having one sampling width is stored in the battery temperature gradient storage means 532 (step 515). The battery temperature gradient dT / dt (in12) of the first sampling width is compared to be positive or negative (step 516). If it is not negative, the time of 60 seconds or more has elapsed for 12 samplings, and the battery temperature of the first sampling width Since the calculation of the gradient is started, the battery temperature gradient dT / dt (in12) of the first sampling width is compared with the battery temperature gradient minimum value dT / dt (MIN12) of the first sampling width (step 517), When the battery temperature gradient dT / dt (in12) of the first sampling width is smaller than the battery temperature gradient minimum value dT / dt (MIN12) of the first sampling width, the battery temperature gradient minimum value dT / dt ( MIN12) is updated (step 518), and the battery temperature gradient dT / dt (in12) with the first sampling width is the battery with the first sampling width. If not larger than degrees gradient minimum dT / dt (MIN12) skips step 518. In addition, when the battery temperature gradient dT / dt (in 12) of the first sampling width is negative in step 516, the time of 60 seconds or more for 12 samplings has not elapsed, and the battery temperature gradient of the first sampling width is calculated. Since it has not started, step 517 and step 518 are skipped. Next, it is determined whether or not the 45 ° C flag is 1 (step 519). If it is not 1, it is compared whether or not Tin has reached 45 ° C. (step 520), and it is determined that 45 ° C. has been reached. If the battery temperature gradient dT / dt (in 36) of the second sampling width is negative or positive (step 521), the 45 ° C flag is set to 1 if it is determined that the battery temperature gradient dT / dt (in 36) is not negative (step 522).

  Next, it is determined whether or not the cooling effect flag is 1 (step 523). In step 523, if the flag with cooling effect is 1, that is, if the charging current is I1, which will be described later, the battery temperature gradient minimum value dT / dt (in the first sampling width) from the latest battery temperature gradient dT / dt (in12). MIN12) is subtracted, and the subtraction result is compared with a predetermined value N1 to detect full charge (step 524).

  When the subtraction result is less than or equal to the predetermined value N1, Ti-35 → Ti-36, Ti-34 → Ti-35,..., Ti-01 → Ti-02, Tin → Ti-01 are stored. The data is transferred to the storage area before one sampling (step 528), and the processing from step 506 is performed again. If the subtraction result exceeds the predetermined value N1, charging is terminated (step 529), and when the battery pack 2 is removed from the charger (step 530), the cooling fan 6 is stopped (step 531), The processing from step 501 is performed again.

  If the cooling effect present flag is not 1 in step 523, it is determined whether or not the cooling effect absent flag is 1 (step 525). In step 525, when the no cooling effect flag is 1, that is, when the charging current is I2, which will be described later, the latest battery temperature gradient dT / dt (in12) to the battery sampling gradient minimum value dT / dt (in the first sampling width). MIN12) is subtracted and the result of subtraction is compared with a predetermined value N2 to detect full charge (step 526).

  When the subtraction result is less than or equal to the predetermined value N2, Ti-35 → Ti-36, Ti-34 → Ti-35,..., Ti-01 → Ti-02, Tin → Ti-01 are stored. The data is transferred to the storage area before one sampling (step 528), and the processing from step 506 is performed again. When the subtraction result exceeds the predetermined value N2, charging is terminated (step 529), and when the battery pack 2 is removed from the charger (step 530), the cooling fan 6 is stopped (step 531), The processing from step 501 is performed again.

  In step 525, when the no cooling effect flag is not 1, charging is performed with the charging current I0, and the battery temperature gradient minimum value dT of the first sampling width from the latest battery temperature gradient dT / dt (in12). Full charge detection is performed by subtracting / dt (MIN12) and comparing the subtraction result with a predetermined value N0 (step 527).

  When the subtraction result is less than or equal to the predetermined value N0, Ti-35 → Ti-36, Ti-34 → Ti-35,..., Ti-01 → Ti-02, Tin → Ti-01 are stored. The data is transferred to the storage area before one sampling (step 528), and the processing from step 506 is performed again. When the subtraction result exceeds the predetermined value N0, charging is terminated (step 529), and when the battery pack 2 is removed from the charger (step 530), the cooling fan 6 is stopped (step 531), The processing from step 501 is performed again.

  If it is determined in step 520 that the battery temperature has not reached 45 ° C., step 521 and step 522 are skipped. If it is determined in step 521 that the battery temperature gradient dT / dt (in 36) of the second sampling width is negative, step 522 is skipped.

If the 45 ° C. flag is 1 in step 519, it is compared whether or not the cooling effect flag is 1 (step 532), and if 1, the process jumps to step 523. If the cooling effect present flag is not 1, whether or not the cooling effect absent flag is 1 is compared (step 533), and if 1, the process jumps to step 523. When the no cooling effect flag is not 1, the predetermined value P1T0 based on the battery temperature T0 at the start of charging is compared with the battery temperature gradient dT / dt (in36) of the second sampling width (step 535), and at the start of charging. When the minimum battery temperature gradient dT / dt ( MIN 36) of the second sampling width is smaller than a predetermined value P1T0 based on the battery temperature of the battery pack, it is determined that there is a cooling effect, and the battery pack considering the cooling effect The battery is charged with the first charging current I1 (<I0) that is the maximum current value that can suppress the deterioration of the battery life due to the heat generation of 2 (step 536), and the flag with cooling effect is set to 1 (step 537). Then, the process jumps to step 523.

In step 535, if the battery temperature gradient minimum value dT / dt ( MIN 36) of the second sampling width is larger than the predetermined value P1T0 based on the battery temperature at the start of charging, it is determined that there is no cooling effect, and cooling is performed. Considering that there is no effect, the battery pack 2 is charged with the second charging current I2 (<I1), which is the maximum current value that can suppress the deterioration of the battery life due to heat generation (step 538), and the cooling effect The absence flag is set to 1 (step 539), and then the process jumps to step 523.

  Next, referring to the circuit diagram of FIG. 3 and the flowcharts of FIGS. 7 and 8, the battery temperature gradient when the battery temperature gradient of the second sampling width during charging in the present invention is first calculated is preset. The operation in the case where the presence or absence of the cooling effect is determined based on whether or not it is greater than two predetermined values will be described.

  When the power is turned on, the microcomputer 50 initially sets the output ports 56a and 56b, and enters a connection standby state for the battery pack 2 (step 601). When the battery pack 2 is connected, the cooling fan 6 operates (step 602), and then charging is started with the charging current I0 (step 603).

The battery temperature Ti-36, Ti-35,..., Ti-01 before the sampling of the storage data of the battery temperature storage means 531 and the latest battery temperature of the storage data of the battery temperature gradient storage means 532 and 12 samplings. a temperature gradient minimum value dT / dt of the first sampling interval computed from the previous battery temperature (MIN12), the cooling effect flag, the cooling effect determination flag, 45 ° C. flag, I3 flag, the I4 flag initial setting (Step 604), the sampling timer is started (Step 605). When the sampling timer time Δt has elapsed (step 606), the sampling timer is started again (step 607). In this example, the sampling timer time Δt is 5 seconds. The battery temperature gradient of the first sampling width is a value obtained by dividing the subtraction result between the latest battery temperature and the battery temperature before 12 samplings by the time of 12 samplings for 60 seconds. The battery temperature gradient of the second sampling width is a value obtained by dividing the subtraction result between the latest battery temperature and the battery temperature gradient before 36 sampling by the time of 36 samplings for 180 seconds.

  Next, the divided voltage value obtained by dividing the battery temperature Tin by the battery temperature detecting means 90 by the resistors 91 and 92 is A / D converted by the A / D converter 55 and taken in as the battery temperature (step 608). At this time, when the sampling timer is started for the first time (step 609), the captured battery temperature Tin is stored in the battery temperature storage means 531 as the battery temperature T0 at the start of charging (step 610). Next, the battery temperature before 36 samplings is subtracted from the battery temperature Tin, the value is divided by the time for 36 samplings for 180 seconds, and the value (Tin−Ti−36) / 180 is divided into the battery temperature gradient of the second sampling width. It is stored in the battery temperature gradient storage means 532 as dT / dt (in 36) (step 611).

  Next, it is compared whether or not the cooling effect judged flag is 1 (step 612). If it is not 1, whether the battery temperature gradient dT / dt (in36) of the second sampling width is positive or negative is compared. (Step 613) If it is not negative, the sampling time of 36 seconds has passed 180 seconds or more, and the calculation of the battery temperature gradient of the second sampling width has started, so a predetermined value based on the battery temperature T0 at the start of charging P2T0 is compared with the battery temperature gradient dT / dt (in 36) of the second sampling width (step 615). If the battery temperature gradient dT / dt (in 36) of the second sampling width is smaller than the predetermined value P2T0 based on the battery temperature at the start of charging, it is determined that there is a cooling effect, and the cooling effect flag is set to 1 (step 616). Next, the cooling effect judged flag is set to 1. If the battery temperature gradient dT / dt (in36) of the second sampling width is larger than the predetermined value P2T0 based on the battery temperature at the start of charging, it is determined that there is no cooling effect and the cooling effect flag is set to 0 (step 617). Then, in step 618, the cooling effect determined flag is set to 1.

  In step 612, whether or not the cooling effect determined flag is 1 is compared. If it is determined that the flag is 1, the process of step 619 is performed.

  In step 613, if the battery temperature gradient dT / dt (in 36) of the second sampling width is negative, the process of step 619 is performed.

  Next, the battery temperature Ti-12 before 12 sampling is subtracted from the battery temperature Tin previously taken in, and the value is divided by the time of 60 seconds corresponding to 12 samplings, and the value (Tin-Ti-12) / 60 is divided into The battery temperature gradient storage unit 532 stores the battery temperature gradient dT / dt (in 12) having one sampling width (step 619). The battery temperature gradient dT / dt (in12) of the first sampling width is compared to be positive or negative (step 620). If it is not negative, the time of 60 seconds or more has elapsed for 12 samplings, and the battery temperature of the first sampling width Since the calculation of the gradient is started, the battery temperature gradient dT / dt (in12) of the first sampling width is compared with the battery temperature gradient minimum value dT / dt (MIN12) of the first sampling width (step 621), When the battery temperature gradient dT / dt (in12) of the first sampling width is smaller than the battery temperature gradient minimum value dT / dt (MIN12) of the first sampling width, the battery temperature gradient minimum value dT / dt ( MIN12) is updated (step 622) and the battery temperature gradient dT / dt (in12) with the first sampling width is the battery with the first sampling width. Degrees slope minimum dT / dt (MIN12) greater than skips step 622. In addition, when the battery temperature gradient dT / dt (in12) of the first sampling width is negative in step 620, the time of 60 seconds or more for 12 samplings has not elapsed, and the battery temperature gradient of the first sampling width is calculated. Since it has not started, step 621 and step 622 are skipped. Next, it is determined whether or not the 45 ° C. flag is 1 (step 623). If it is not 1, it is compared whether or not the battery temperature Tin has reached 45 ° C. (step 624). If it is determined, whether the battery temperature gradient dT / dt (in 36) of the second sampling width is negative or positive is compared (step 625). If it is positive, the 45 ° C. flag is set to 1 (step 626).

  Next, it is determined whether or not the I3 flag is 1 (step 627). In step 627, when the I3 flag is 1, that is, when the charging current is I3 described later, the battery temperature gradient minimum value dT / dt (MIN12) of the first sampling width from the latest battery temperature gradient dT / dt (in12). Is subtracted and the subtraction result is compared with a predetermined value N3 to detect full charge (step 628).

  When the subtraction result is less than or equal to the predetermined value N3, Ti-35 → Ti-36, Ti-34 → Ti-35,..., Ti-01 → Ti-02, Tin → Ti-01 are stored. The data is transferred to the storage area before one sampling (step 632), and the processing from step 606 is performed again. When the subtraction result exceeds the predetermined value N3, charging is finished (step 633), and when the battery pack 2 is removed from the charger (step 634), the cooling fan 6 is stopped (step 635), The processing from step 601 is performed again.

  If the I3 flag is not 1 in step 627, it is determined whether or not the I4 flag is 1 (step 629). In step 629, if the I4 flag is 1, that is, if the charging current is I4 described later, the battery temperature gradient minimum value dT / dt (MIN12) of the first sampling width from the latest battery temperature gradient dT / dt (in12). Is subtracted and the subtraction result is compared with a predetermined value N4 to detect full charge (step 630).

  When the subtraction result is less than or equal to the predetermined value N4, Ti-35 → Ti-36, Ti-34 → Ti-35,..., Ti-01 → Ti-02, Tin → Ti-01 are stored. The data is transferred to the storage area before one sampling (step 632), and the processing from step 606 is performed again. When the subtraction result exceeds the predetermined value N4, charging is terminated (step 633), and when the battery pack 2 is removed from the charger (step 634), the cooling fan 6 is stopped (step 635), The processing from step 601 is performed again.

  In step 629, when the I4 flag is not 1, charging is performed with the charging current I0, and the battery temperature gradient minimum value dT / dt of the first sampling width from the latest battery temperature gradient dT / dt (in12). (MIN12) is subtracted, and the subtraction result is compared with a predetermined value N0 to detect full charge (step 631).

  When the subtraction result is less than or equal to the predetermined value N0, Ti-35 → Ti-36, Ti-34 → Ti-35,..., Ti-01 → Ti-02, Tin → Ti-01 are stored. The data is transferred to the storage area before one sampling (step 632), and the processing from step 606 is performed again. When the subtraction result exceeds the predetermined value N0, charging is terminated (step 633), and when the battery pack 2 is removed from the charger (step 634), the cooling fan 6 is stopped (step 635), The processing from step 601 is performed again.

  If it is determined in step 624 that the battery temperature has not reached 45 ° C., step 625 and step 626 are skipped. If it is determined in step 625 that the battery temperature gradient dT / dt (in 36) of the second sampling width is negative, step 626 is skipped.

  If the 45 ° C. flag is 1 in step 623, whether or not the I3 flag is 1 is compared (step 636), and if it is determined that the I3 flag is 1, the process jumps to step 627. If it is determined in step 636 that the I3 flag is not 1, whether or not the I4 flag is 1 is compared (step 637). If it is determined in step 637 that the I4 flag is 1, the process jumps to step 627. If it is determined that the I4 flag is not 1, whether or not the cooling effect flag is 1 is compared (step 638), and if it is determined that the cooling effect flag is 1, the battery pack considering that there is a cooling effect The battery is charged with the third charging current I3 (<I0) that is the maximum current value that can suppress the deterioration of the battery life due to the heat generation of 2 (step 639), the I3 flag is set to 1 (step 640), and then Jump to step 627. If it is determined in step 638 that the cooling effect flag is not 1, the maximum current value that can suppress the deterioration of the battery life due to the heat generation of the battery pack 2 in consideration of the absence of the cooling effect. Charging is performed with four charging currents I4 (<I3) (step 641), the I4 flag is set to 1 (step 642), and then the routine jumps to step 627.

  By determining whether or not there is a cooling effect by the method as described above, if the ventilation holes of the battery pack and the charging device are clogged due to foreign matter etc. in the cooling compatible battery pack, there is no cooling effect. Appropriate charging can be performed.

The graph which shows transition of the battery temperature gradient computed by the charging voltage, charging current, and the 1st and 2nd sampling width when charging the battery pack for cooling. The graph which shows transition of the battery temperature gradient computed by the charging voltage, charging current, 1st and 2nd sampling width when charging the battery pack which does not support cooling. The circuit diagram which shows one Embodiment of this invention charging device. When a battery temperature is reached, the minimum battery temperature gradient until reaching that temperature is judged whether the cooling effect is present or not by a certain value. Graph showing. For explaining the operation of determining whether or not there is a cooling effect based on whether or not the minimum value of the battery temperature gradient when the battery temperature during charging of the charging device of the present invention reaches a predetermined temperature is greater than a preset first predetermined value. The first half of the flowchart. The second half of the flowchart of FIG. For explaining the operation of determining whether or not there is a cooling effect based on whether or not the battery temperature gradient immediately after being calculated by the battery temperature gradient of the second sampling width by the cooling fan of the charging device of the present invention is greater than a predetermined second predetermined value. The first half of the flowchart. The second half of the flowchart of FIG.

Explanation of symbols

  2 is a battery pack, 6 is a cooling fan, 50 is a CPU 51 having an arithmetic function, a battery temperature storage means 531, a microcomputer having battery temperature gradient storage means 532, etc., and 90 is a battery temperature detection means.

Claims (2)

A cooling fan for cooling the battery pack, a battery temperature detecting means for detecting the battery temperature, a battery temperature storing means for storing the battery temperature based on an output of the battery temperature detecting means, a battery temperature detecting means and a battery temperature storing means A battery temperature gradient calculating means for calculating a battery temperature gradient based on an output; and a battery temperature gradient storage means for storing a battery temperature gradient based on an output of the battery temperature gradient calculating means,
The battery temperature storage means stores a battery temperature gradient minimum value, and a battery temperature gradient minimum value when a battery temperature during charging reaches a predetermined temperature at which the presence or absence of a cooling effect can be determined is preset to a first predetermined value. A charging device characterized in that the presence or absence of a cooling effect by a cooling fan is determined by whether or not it is larger. Wherein the first predetermined value to determine the presence or absence of the cooling effect, the charging device according to claim 1, characterized in that so as to set corresponding to the battery temperature at the start of charging.

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