JPH10210675A - Charge control method and charge controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the charge waiting time and the time required for charge by charging a battery with a pulse current, which is made by turning on and off the current and whose maximum value is not over the quick charge current, when the battery temperature is at or under the lower limit value where a quick charging of the battery is possible. SOLUTION: A battery temperature detector 34 amplifies the current charge of a thermistor which changes by a battery temperature T, and converts it into a specified voltage, and inputs it into a CPU 26. However, it performs charge, suppressing the average current low, by turning on the off a relatively large charge current into a pulse current in the case that the battery temperature is lower than the temperature range where the battery can be charged quickly. However, the maximum value of the pulse current is the current of quick charge. Then, when the battery temperature T reaches the set value not less than the lower limit value of the temperature range, where the charge is possible in the middle of charge, it shifts to quick charge, and when the battery temperature T goes down to the lower limit value or under in the middle of quick charge, the charge is stopped, and it goes into standby. As a result, the battery is charged with a pulse current being made by turning on and off the current whose maximum value is not over the quick charge current, so a charge-standby time and the required time for charging can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge control method for a secondary battery represented by a nickel-cadmium battery, a nickel-metal hydride battery, and the like, and a charge control device.

[0002]

2. Description of the Related Art In a rechargeable secondary battery, an upper limit and a lower limit of a charging start temperature are set, and charging is started when the battery temperature is within the set range. That is, if the battery is charged at a temperature outside the set temperature range determined by the type and type of the battery, the battery may be deteriorated, the charging efficiency may be reduced, and liquid leakage (drying) may occur. Here, the charging efficiency is the ratio of the amount of electricity actually stored in the battery to the amount of electricity charged.

[0003] There are various types of charge control, which can be broadly classified into normal charge and quick charge according to the charge current value. Ordinary charging is a method of charging for a long time with a relatively small current. The rapid charging is a method of terminating charging with a relatively large current in a short time.

[0004]

In the conventional method, when the battery temperature is out of the range between the upper limit value and the lower limit value of the charging start temperature, charging cannot be started, and it is necessary to wait until the battery temperature falls within this range. .

When the battery temperature is lower than the lower limit, the ambient temperature is generally considered to be lower than the lower limit. Therefore, it is necessary to wait until the ambient temperature rises. In some cases, charging will not start even if you wait for a long time. For this reason, there was a problem that the required charging time was significantly long.

In many secondary batteries such as nickel cadmium and the like, a large amount of gas is generated due to a chemical reaction in the battery during charging at a low temperature, causing an increase in battery internal pressure. This increase in internal pressure promotes battery deterioration, and becomes more remarkable as the charge current value increases. Therefore, at the time of rapid charging with a large charging current, the lower limit of the rechargeable battery temperature is set slightly higher than at the time of normal charging. For example, when the lower limit is set to 0 ° C. for normal charging, the lower limit is set to 5 ° C. for rapid charging. For this reason, since the lower limit value for quick charging is particularly high, a situation where quick charging cannot be started is likely to occur.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to reduce the charging standby time and the charging required time when the battery temperature is equal to or lower than the lower limit of the battery temperature at which rapid charging is possible. A first object is to provide a charge control method that can be performed. It is a second object of the present invention to provide a charge control device directly used for implementing the method.

[0008]

According to the present invention, a first object of the present invention is to provide a charge control method for rapidly charging a battery with a battery management device for managing a charge / discharge state. A charge control method is characterized in that a current whose maximum value does not exceed the rapid charge current is charged with a pulse current whose on / off control is performed in the following cases.

In this case, by setting the maximum value of the pulse current as the rapid charging current, the rapid charging circuit can be used as it is without providing a special circuit for the pulse current in the charger. ,convenient. If the battery temperature rises to a set value slightly higher than the lower limit during charging with the pulse current (hereinafter also referred to as low-rate charging), it is possible to shift to normal rapid charging. When the battery temperature falls to a set value equal to or lower than the lower limit value during the charging by the pulse current (low-rate charging), it is preferable to stop the charging and stand by to protect the battery.

According to a second aspect of the present invention, in a charge control device for rapidly charging a battery with a battery management device for managing a charge / discharge state by a charger, a temperature detection unit of the battery;
A charging control unit that instructs charging by a pulse current whose maximum value does not exceed the rapid charging current when the detected battery temperature is equal to or lower than the lower limit capable of rapid charging, wherein the battery management device includes: The charging is performed by the charging current according to the instruction.

[0011]

FIG. 1 is an overall conceptual diagram showing an embodiment of the present invention, FIG. 2 is a diagram mainly explaining the functions of a CPU, FIG. 3 is a flowchart showing an operation during preparation for charging, and FIG. 5 is a flowchart showing the first half of the operation in the charging mode, FIG. 6 is a flowchart showing the latter half of the operation, FIG. 7 is a flowchart showing the operation in the low-rate charging mode using the pulse current, and FIG. Flow chart of temperature detection interrupt operation,
FIG. 9 is a flowchart of a temperature detection interrupt operation at the time of quick charging, and FIG.
0 is a flowchart of a temperature detection interrupt operation at the time of low-rate charging.

1 and 2, reference numeral 10 denotes a motor, 12
Is a controller, 14 is a battery management device, and 16 is a charger. Battery management device 14 includes a battery 18 such as a nickel-cadmium battery. The AC supplied from the AC power supply 20 is rectified by the charger 16 and charges the battery 18 via the diode 22 in a predetermined charging mode.

The controller 12 supplies a predetermined current and voltage to the motor 10 using the battery 18 as a power source, and
Drive 0. For example, when the motor 10 is a DC motor, the controller 12 may be of a chopper type that controls on / off of the output voltage of the battery 18 at a predetermined duty.

The controller 12 controls the drive voltage and current of the motor 10 by continuously changing the duty based on the external signal B during normal operation. In a situation where discharge is prohibited, such as during charging, the controller 12 sets the duty to 0. That is, the voltage to the motor 10
The supply of the current is stopped, and the fact is displayed on the display device 24.

Reference numeral 26 denotes a battery CPU (microprocessor). Its function will be described later. Reference numeral 28 denotes a power supply circuit (FIG. 2), and the voltage of the battery 18 (for example, 24 V)
Is reduced to a predetermined voltage (for example, 5 V) to drive the CPU 26 and the like.

Reference numeral 30 denotes a current detector, and 32 denotes a voltage detector. The current detection unit 30 detects the charge / discharge current I of the battery 18 and converts it into a signal of a predetermined voltage and inputs the signal to the CPU 26. The voltage detector 32 converts the positive voltage V of the battery 18 into a signal of a predetermined voltage and inputs the signal to the CPU 26.

Numeral 34 denotes a battery temperature detecting section comprising a thermistor provided on the battery 18. More specifically, the battery temperature detecting section 34 amplifies a current change of the thermistor 34 which changes according to the battery temperature T, converts the current into a predetermined voltage, and inputs it to the CPU 26. Here, the battery temperature T is the temperature of the battery 18, for example, the temperature of the battery surface.

In FIG. 2, reference numeral 36 denotes an EEPROM as a memory.
(Electrically Erasable / Programmable Read Only Mem
ory). The EEPROM 36 stores various data used in the calculation by the CPU 26, for example, the type of the battery 18 and its characteristic data, a capacity reduction characteristic due to the battery temperature T, and the like. And so on.

Next, the function of the CPU 26 will be described. CPU
26 performs an initialization process when an activation command is received from the controller 12 or the charger 16. Although the CPU 26 operates by software, its function is shown in a block diagram in FIG.

The CPU 26 first determines whether or not charging is being performed by the charger 16 using the charging determination unit 40. In this determination, the voltage Vc of the power line 42 between the diode 22 and the charger 16 is digitized and input to the CPU 26. If the voltage Vc is equal to or higher than a predetermined positive voltage, it is determined that charging is in progress, and the communication is performed via the communication interface 38. Display on the display device 24, and the LED 54 described later is turned on. At this time, the charging method is determined from the magnitude of the charging current and is instructed to the charger 16, which will be described later.

During this charging, the CPU 26 calculates the amount of charge by the remaining capacity calculator 44 (FIG. 2). That is, the charge amount is determined by the product (ampere hour) of the current I detected by the battery current detection unit 30 and the charging time.

The initial capacity of the battery 18 is stored in the EEPROM 36 in advance, and when the integrated value of the charged amount exceeds the initial capacity, the charged amount is set to the initial capacity. Prevent accumulation. When the charging is completed according to the charging method, the charged amount is reset to the initial capacity.

On the other hand, the CPU 26 may obtain the electric power from the product of the voltage and the current during charging, and may correct the charged amount according to the magnitude of the electric power (power correction). This correction is performed in consideration of the fact that the charging efficiency changes depending on the magnitude of the charging current and the charging method. This result is stored in the EEPROM 36, sent to the controller 12 via the communication interface 38 as necessary, and displayed on the display device 24.

The CPU 26 determines whether or not the battery is discharging from the flow direction of the battery current I. If it is determined that the battery is discharging, the remaining capacity calculator 44 calculates the amount of discharge. That is, the amount of discharge (ampere hours) is obtained by integrating time with the discharge current detected by the battery current detection unit 30. The remaining capacity calculating section 44 may calculate the self-discharge amount depending on the battery temperature to correct the remaining capacity. The remaining capacity calculator 44 calculates these results as EEP
The current value of the remaining capacity is obtained by subtracting from the remaining capacity stored in the ROM 36.

It is needless to say that the above-described correction by the power change (power correction) may be added to the present value. The corrected remaining capacity is stored in the EEPROM 36.
The result is sent to the controller 12 via the communication interface 38 and displayed on the display device 24.

Next, the charger 16 will be described with reference to FIG.
The charger 16 has an AC / DC converter 46 for converting an alternating current supplied from the power supply 20 to a direct current, a charging current detecting unit 48, a duty calculating unit 50, and an output control unit 52. The duty calculation unit 50 determines a duty for outputting a charging current specified by the battery management device 14. The output control unit 52 outputs a signal (PWM signal) for on / off control of the switching element of the converter 46 in accordance with the duty.

The charger 16 has an LED (light emitting diode) 54 as a charge display section and an LE for driving the LED.
And a D driver 56. A signal indicating that the battery is being charged, which is sent from the battery management device 14, is input to the LED driver 56, and the LED 54 is turned on based on this signal.

In FIG. 2, reference numeral 57 denotes a discharge degree judging unit. The discharge degree determination unit 57 determines whether the battery 1
8 is used to detect the degree of discharge, and this degree of discharge is used to determine whether or not charging is necessary. Here, it is assumed that the charge start command is input, for example, by operating a charge start switch (not shown) provided in the charger 16. Further, the charge determination unit 40 determines the voltage Vc of the power line 42.
The charge start command may be input to the discharge degree determination unit 57 when it is determined that is equal to or higher than the predetermined voltage.

Various data can be used as the data for determining the discharge level used by the discharge level determination section 57.
Here, it is determined from the data in the EEPROM 36 whether or not there has been a discharge command after the previous charge, and this is used as a material for determining the degree of discharge. In addition, the amount of self-discharge and the remaining capacity after the previous charge are used.

The data indicating the degree of discharge is input to the charging necessity judging section 58, where the necessity of charging is judged. For example, when no discharge has been performed since the last charge,
At this time, when the self-discharge amount is equal to or less than the predetermined value or when the remaining capacity is equal to or more than the predetermined value, it is determined that the charging is unnecessary. When it is determined that charging is not necessary, a signal to stop charging is sent to the charger 16 and the display device LE
D54 is turned on for a predetermined time. Such a state is referred to herein as “fake charging”.

Next, the operation will be described with reference to FIGS.
First, when the voltage Vc of the power line 42 of the charger 16 becomes equal to or higher than the set value or when the charge start switch is manually operated, a charge start command is input to the discharge degree determination unit 57 (step in FIG. 3). 100). Discharge degree judgment unit 5
7, when the charge start command is input, the number of times of discharging after the previous charging is obtained based on the history data stored in the EEPROM 36.

The charge necessity judging section 58 judges necessity of charging based on the number of discharges. In this embodiment, if the number of discharges is 0, it is determined that charging is unnecessary (step 10).
2). If the number of discharges is even one, it is determined whether the remaining capacity of the battery 18 is equal to or less than a predetermined value (step 10).
4). Here, the remaining capacity is calculated by the remaining capacity calculation unit 44. Therefore, in this case, the remaining capacity calculation unit 44 also functions as a discharge degree detection unit that detects the degree of discharge.

In step 102, if no discharging has been performed since the previous charging, the charging necessity determining unit 5
In step 8, it is determined whether or not the previous charging was completed or the charging was completed by insufficient charging based on the data in the EEPROM 36 (step 106). When charging is incomplete, step 104 is entered. That is, if the remaining capacity is small, the process proceeds to step 108 for determining the quality of the battery, and if the remaining capacity is large, the process proceeds to step 110.

In step 110, the self-discharge amount is calculated, and the self-discharge amount is set to a predetermined value (for example, 400 mAh).
If so, the charging mode 100 is entered, and if so, the charging mode is entered (step 112). That is, without actually charging, the clocking by the false charging timer is started and only the LED 54 is turned on (step 11).
2). When a predetermined time set in the fake charging timer has elapsed (step 114), the LED 54 is turned off (step 116), and the fake charging mode ends. In the false charging mode, the charging current may be set to 0, but a minute current may be kept flowing.

Here, the calculation of the amount of self-discharge in step 110 uses the characteristic of the rate of decrease in the remaining capacity with respect to the battery temperature T. In other words, the amount of self-discharge increases with an increase in the standing time and the battery temperature. Since this relationship is determined for the battery 18, this relationship is stored in the EEPROM 36 in advance. Therefore, if the battery temperature T and the time during which the battery 18 is left are obtained, the self-discharge amount can be obtained using this relational expression (or a map showing this relation).

The calculation of the amount of self-discharge can be performed by the remaining capacity calculator 44. Thus, in this embodiment,
The remaining capacity calculation unit 44 also serves as a discharge degree determination unit for obtaining the self-discharge amount. When calculating the remaining capacity, the remaining capacity calculating unit 44 may perform correction based on the self-discharge amount.

In step 104, when the remaining capacity is equal to or less than a predetermined value, and in step 110, the self-discharge amount is set to a predetermined value (40
If it is equal to or greater than 0 mAh), the routine proceeds to step 108, where it is determined whether or not the battery 18 is unusable after being left for a long time. Therefore, first, when the battery voltage V is normal (for example, 24
V) is determined (step 108). When the battery voltage V reaches the threshold value (16
V) or less, the mode is the pre-charge mode (step 120).
2)

In the pre-charge mode (step 120),
As shown in FIG. 4, the charging is started with a small charging current (0.5 A), the time of the pre-charge timer for a fixed time (for example, 1 hour) is started, and the LED indicating that the apparatus is in a standby state is turned on ( Step 124). Then, it is monitored whether or not the battery voltage V recovers to the threshold value (16 V) or more (steps 126 and 128).

When the battery voltage V recovers above this threshold value (16 V), the battery 18 is considered usable and the pre-charging is terminated (step 130). That is, the charging current is set to 0, and the LED indicating standby is turned off. Then, the charging mode (step 122) is entered. If the battery voltage V does not recover to the threshold value (16 V), it is determined that the battery 18 cannot be used after being left for a long period of time, and a display indicating that the battery is abnormal is displayed (step 132). At this time, the charging current is set to 0, and the LED indicating standby is turned off.

Next, the charging mode (step 122) is shown in FIG.
This will be described with reference to FIGS. When the charger 16 is turned on, the degree of discharge of the battery 18 is small, and it is determined that the battery is not defective, and the charging mode (step 122) is entered, the CPU 26 measures the temperature based on the signal output from the thermistor 34. The battery temperature T is determined by the unit 60.

The CPU 26 determines whether or not the battery temperature T falls within a chargeable temperature range (0 <T <40 ° C.) (step 200). If it is not within this temperature range, the process waits as it is and waits for it to enter this temperature range (step 201). At this time, a standby LED (not shown) that indicates that the apparatus is in standby is turned on.

When the temperature falls within this temperature range, test charging is started (step 202). In this test charging, the output of the charger connected to determine the charging method is turned on, and the charger output current I at this time is obtained. In order to improve the battery cycle life and the charging efficiency, it is desirable to apply a charging method that is optimal for the current amount based on the charging current I (step 204).

When the power of the charger 16 is turned on, the charging current I is unstable and fluctuates. Therefore, a slight delay time (about several milliseconds) is set, and the determination is made using the stable charging current I. The stability of the current I may be determined by calculating the rate of change (the amount of change per unit time) of the charging current I and determining that the rate of change has become equal to or less than a predetermined value. The current stability determination unit 62 in FIG. 2 determines the magnitude of the change rate. Also 6
Reference numeral 4 denotes a charging method determining unit that determines the charging method from the charging current I.

The result of the determination of the charging method is transmitted to the charging control unit 6.
6 to perform charging control according to a predetermined charging method. Normal charging is selected as the first method based on the charging current I. In this embodiment, the -ΔV method is selected. This -Δ
The V method focuses on the point where the charging voltage of the Ni-Cd battery drops after reaching the maximum value at the end of charging, and is determined by -ΔV from the maximum value.
It is determined that charging has ended when charging has ended. The calculation of −ΔV is performed by the −ΔV calculation unit 68 in FIG.

The CPU 26 controls the charging current I (for example, 1.5
A) and the value of -ΔV is set (step 20).
6). In this charging method, the CPU 26 sets a timer for 4.5 hours (step 208), and then starts the main charging (step 218 in FIG. 6).

As a second method from the charging current I, quick charging is selected (step 204). Here, the dT / dt method is used as the rapid charging method. This method focuses on a point at which the battery temperature T rises sharply at the end of charging, and ends charging when the rate of change dT / dt of the battery temperature T with respect to time becomes equal to or higher than a set value. This dT /
The calculation of dt is performed by the dT / dt calculation unit 70 in FIG.

When the quick charge is selected (step 204), the battery temperature T is set within a set range (for example, 5 <T <40).
C) is determined (step 210).
If not, wait until you enter. Here, the lower limit of this temperature range is the lower limit (0
The reason why the temperature is 5 ° C. higher than (° C.) is to prevent deterioration of the battery due to an increase in internal pressure due to charging.

When the temperature falls within this temperature range, the charging current I (for example, 5 A) for quick charging and the termination condition are set (step 212). That is, the value of dT / dt is set. Then, after setting the timer to 1.5 hours (step 21)
4), main charging is started (step 218 in FIG. 6). At this time, the charging current I is controlled so as to have the value set in steps 206 and 212 described above.

Even if the battery temperature T is lower than the lower limit (5 ° C.) of the temperature range of step 210 (5 <T <40 ° C.), the lower limit of the temperature range of step 200 (0 <T <40 ° C.) 0 ° C) (0 <T <5 ° C). In this case, low-rate charging is performed (step 216). This low-rate charging will be described later with reference to FIG.

When the main charging starts (step 218) and the timer starts counting, it is determined whether or not the accumulated time of the timer overflows the time set in steps 208 and 214 (step 222). If it has overflowed, supplementary charging is performed by trickle charging in which charging is performed for a predetermined time with a small current (step 226), and charging is completed. If not, charging is continued as it is, charging is performed until the charging end condition set in steps 206 and 212 is satisfied, and then supplemental charging is performed by trickle charging and the charging is completed (step 22).
6). The end of the charging is performed by the charging end determining unit 72 in FIG.

Next, the low-rate charging mode (step 216 in FIG. 5) will be described with reference to FIG. This low-rate charging mode is used when the battery temperature T is lower than the temperature range in which rapid charging is possible (5 <T <40 ° C.) and is within the temperature range in which normal charging is possible (0 <T <40 ° C.). Used. In this mode, a relatively large charging current is turned on / off to be a pulse current, thereby suppressing the average current to a low value (at a low rate).

In this embodiment, the maximum value of the pulse current is set to the rapid charging current (5 A). Therefore, by performing on / off control using the charging circuit of the rapid charging, there is no need to prepare a charging circuit dedicated to low-rate charging.
The circuit configuration of the charger 16 can be simplified.

When the low-rate charging mode is entered (step 216), first, a timer time is set (for example, 3 hours) (FIG. 7, step 230), and charging is started (step 232). When the battery voltage V rises above a set value (for example, 40 V) (step 234), it is determined that the battery has deteriorated and cannot be used, and a display indicating that there is an abnormality in the battery 18 is performed (step 236). Is stopped (step 238).

If the battery voltage V is equal to or less than the set value (40 V), the low-rate charging is continued, and it is determined whether or not a predetermined charging end condition has been reached (step 240). Here -Δ
The end of charging is determined according to the V method. When it is determined that the charging is completed, the charging current is stopped (step 242), the amount of charge by this low-rate charging is calculated to obtain the battery capacity (step 244), and stored in the EEPROM 36. Thereafter, supplementary charging is performed with a small current (trickle charging, step 24).
6), charging is completed (step 248).

If the set time of the timer (3 hours) elapses before reaching the charging end condition (step 250), the charging current is stopped (step 252), and the battery capacity is corrected (step 254). End (Step 25)
6).

During the above operation, the CPU 26 monitors the battery temperature T and performs various operations shown in FIGS.
If the battery temperature T becomes equal to or higher than the upper limit (45 ° C.) of the chargeable temperature range during normal charging (step 260 in FIG. 8),
The charging is stopped (step 262), the battery capacity is determined (step 264), and the trickle charge is performed (step 265), and then the charging is terminated. When the battery temperature T is 40 ° C. or less (step 260), the chargeable temperature range (0 <T <45)
When the temperature is lower than the lower limit (0 ° C.) of (° C.) (−266 ° C.) (step 266), charging is stopped and the apparatus stands by (step 268).

The reason why the set value (−2 ° C.) is lower than the lower limit (0 ° C.) is to take into consideration that the temperature T may slightly decrease due to an endothermic reaction due to charging. If the temperature T recovers to the set value (2 ° C.) or higher during standby, the process returns to normal charging (step 272). During this standby, the timer started in step 208 (FIG. 5) is stopped, and when returning to normal charging in step 272, the timer is restarted.

At this time, the set value of step 272 is set to 2
The degree C is set in consideration of not repeating the operation of stopping the charging when the battery temperature T drops below the set value (−2 ° C.) of step 266 due to an endothermic reaction immediately after returning to normal charging. is there.

If the battery temperature T becomes 45 ° C. or higher during the rapid charging (step 280 in FIG. 9), the charging is stopped (step 282), and the battery capacity is obtained (step 284).
After trickle charging is further performed (step 285), the charging is terminated. When the battery temperature is 45 ° C. or less (step 28)
0) If the temperature falls below 3 ° C. (step 286), the rapid charging is stopped (step 288), and the low-rate charging mode is entered (step 290). At this time, the battery capacity is also corrected.

When the battery temperature T becomes lower than −2 ° C. during the low-rate charging (FIG. 10, step 300), the charging is stopped and the apparatus stands by (step 302), and waits until the temperature T recovers to 2 ° C. or higher. (Step 304) Return to low-rate charging (Step 306). If the temperature T does not drop below −2 ° C. in step 300, the low-rate charging is continued and the temperature T
If the temperature is equal to or higher than 7 ° C. (step 308), the low-rate charging is terminated (step 310). Then, after the settings such as the timer and the battery capacity are changed (step 312), the process returns to the rapid charging (step 314).

The reason why the set value is set to 7 ° C. in step 308 is that the lower limit value of the temperature range in which quick charging is possible (5 <T <40 ° C.) is 5 ° C. Therefore, immediately after returning to the rapid charging mode in step 314. This takes into account that the battery temperature T decreases due to the endothermic reaction.

In this embodiment, the termination condition of the ordinary charging is
Set by the ΔV method, and set the termination condition of the quick charge to dV / d
Although the method is set by the T method, the present invention may of course use other methods, and may use an optimum method based on the type of the battery, the degree of deterioration, and the like. The present invention can be applied to a secondary battery other than a nickel-cadmium battery, and it goes without saying that the charging method and the like may be changed according to the characteristics of the battery. In addition, it is needless to say that the maximum value of the charging current at the time of low-rate charging does not need to match the current of rapid charging.

[0063]

As described above, according to the first aspect of the present invention, when the battery temperature becomes equal to or lower than the lower limit of the rapid charging temperature range, the pulse whose current does not exceed the rapid charging current is controlled to be on / off. Since the battery is charged with the current, the charging standby time and the required charging time can be reduced without causing problems such as deterioration of the battery, reduction of the charging efficiency, and liquid leakage.

In this case, if the maximum value of the pulse current is set as the rapid charging current, a rapid charging circuit can be used.
The circuit configuration of the charger can be simplified (claim 2). Further, when the battery temperature T rises to a set value equal to or higher than the lower limit of the temperature range in which rapid charging is possible during the low rate charging by the pulse current, the low rate charging is continued for uselessly for a long time by shifting to the rapid charging. Thus, efficient charging can be performed without any problem (claim 3).

Conversely, when the battery temperature T falls to a set value below the lower limit, the low-rate charging is stopped and the system is kept on standby to ensure protection of the battery (claim 4). According to the fifth aspect of the present invention, there is provided a charge control device directly used for carrying out this method.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of an embodiment of the present invention.

FIG. 2 is a block diagram mainly showing functions of a CPU;

FIG. 3 is a flowchart showing an operation during preparation for charging.

FIG. 4 is a flowchart showing an operation in a pre-charge mode.

FIG. 5 is a flowchart showing the first half of the operation in the charging mode;

FIG. 6 is a flowchart showing the latter half of the operation in the charging mode.

FIG. 7 is a flowchart showing an operation in a low-rate charging mode using a pulse current.

FIG. 8 is a flowchart of a temperature detection interrupt operation during normal charging.

FIG. 9 is a flowchart of a temperature detection interrupt operation during quick charging.

FIG. 10 is a flowchart of a temperature detection interrupt operation during low-rate charging.

[Explanation of symbols]

 Reference Signs List 10 motor 12 controller 14 battery management device 16 charger 18 battery 26 CPU 34 battery temperature detection unit 44 remaining capacity calculation unit 66 charge control unit

Claims (5)

[Claims] 1. A charge control method for rapidly charging a battery with a battery management device that manages a charge / discharge state, wherein when the battery temperature is equal to or lower than a lower limit value of the battery capable of quick charge, a maximum value indicates a fast charge current. A charge control method characterized by charging a current that does not exceed a pulse current with on / off control. 2. The charge control method according to claim 1, wherein the maximum value of the pulse current is set to a rapid charge current. 3. The charge control method according to claim 1, wherein a transition to quick charge is made upon detecting that the battery temperature has risen to a set value equal to or higher than a lower limit value at which quick charge is possible during charging by pulse current. 4. The charging control method according to claim 1, wherein the charging is stopped upon detecting that the battery temperature has dropped to a set value equal to or lower than a lower limit value during charging by the pulse current. 5. A charge control device for rapidly charging a battery with a battery management device for managing a charging / discharging state using a charger, comprising: a battery temperature detecting unit; A charging control unit that instructs charging by a pulse current whose maximum value does not exceed the rapid charging current, the battery management device includes: a charging unit that performs charging by the pulse current according to the instruction of the charging control unit. Charge control device.