JP2504366Y2 - Automatic charger - Google Patents

Description

[Detailed description of the device]

[0001]

This invention is used, for example, to charge a storage battery mounted on an electric vehicle. When the charging voltage reaches an inflection point by charging with a constant initial charging current, the charging current becomes smaller than the initial charging current. The present invention relates to a so-called two-stage constant current type automatic charger that charges with a late charging current.

[0002]

2. Description of the Related Art In an electric vehicle or the like, it is desired to charge the battery rapidly in order to shorten the charging time in order to improve the operating rate. In order to charge the battery rapidly, conventionally, as shown in FIG. 4, charging is started with a relatively large constant initial charging current I ₀ , and when the charging voltage V reaches an inflection point, that is, a constant voltage V _c , the storage battery The charging current I _{1 in the} latter stage of charging, where the chemical reaction of the liquid becomes active and the amount of gas (mainly hydrogen) generated increases, is reduced to about one third of the initial charging current I ₀ ,
A two-stage constant current method has been widely used in which charging is performed with the latter charging current I ₁ and the charging voltage reaches a predetermined value, that is, the completion of charging is detected and the charging is terminated.

[0003]

In the conventional two-stage constant current charging, when the maximum value of the current that can be taken out from the storage battery to be charged is larger than the initial charging current I _{0 of the} charger, especially in the latter charging period. (Charging time after inflection point voltage) T
₂ becomes longer and the charging time T _A as a whole becomes longer, so that the utilization rate of the storage battery, for example, an electric vehicle, is reduced accordingly.

On the contrary, when the maximum current of the storage battery is small, there is a problem that a large amount of gas is generated during the latter charging period T ₂ and the battery liquid becomes insufficient. In either case, it is necessary to make the late charging current I ₁ sufficiently small in order to reduce the amount of gas generation, and there is a drawback that the latter charging time is considerably long.

[0005]

According to the invention of claim 1, the time from the start of charging until the charging voltage reaches the inflection point (initial charging time T ₁ ) is measured and is proportional to this time T _1. The latter charging current is set with. According to the second aspect of the invention, in the first aspect of the invention, the liquid temperature of the storage battery is further measured, and the late charging current is changed in inverse proportion to the measured liquid temperature.

According to the invention of claim 3, when the storage battery is charged with a constant initial charging current and the charging voltage reaches the inflection point,
The battery temperature of the storage battery is measured by the charger that charges with the latter charging current smaller than the initial charging current, and the latter charging current is changed in inverse proportion to the measured liquid temperature.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the main part of the processing operation of a controller in the embodiment of the invention of claim 2, and FIG. The charging power source 12 such as a commercial power source is connected to the input terminal 11 of the charger.
Is connected to the output terminal 21 through the contact 13 of the electromagnetic contactor, the overcurrent detection thermal relay 14, the transformer 15, the rectifier 16, the smoothing circuit 17, the control transistor 18, and the current detection Hall element 19. A storage battery 22 to be charged is connected to the output terminal 21.

The controller 23 includes a one-chip microcomputer (MPU) 24, and the normal / equal changeover switch 2
Every time the switch 5 is turned on, the charging system is switched alternately between the normal charging system and the uniform charging system, and either the normal charging indicator light 26 or the uniform charging indicator light 27 is turned on. First, looking at this display, the switch 25 is controlled to select the charging system (S ₁ ). Next, the charging ON / OFF switch 28 is turned on (S ₂ ). Then, the one-chip MPU 24 controls the solid-state relay (SSR) 31 via the drive circuit 29 to control the electromagnetic contactor coil 32, and closes the contact 13 of the one-chip MPU 24. To start. Further, the one-chip MPU 24 gives a control start signal to the voltage / current control circuit 35, and the voltage control circuit 35 controls the base current of the transistor 18 by the signal to supply the DC power given to its collector to the initial charging voltage, charging The initial current I ₀ is supplied to the storage battery 22 to start charging it. Further, in the liquid of the storage battery 22, the thermistor 3
6 is provided, the thermistor 36 is connected to the power supply circuit 37 in the controller 23 through the resistor 38, and
A current corresponding to the liquid temperature of the storage battery 22 generated at the connection point of the thermistor 36 and the resistor 38 is taken into the A / D converter in the one-chip MPU 24, and the one-chip M
The PU 24 sets the liquid temperature X ₁ of the storage battery 22 immediately after the start of charging to RA
Stored in the M39 (S _3).

The one-chip MPU 24 is a transistor 18
Of the emitter voltage, that is, the charging voltage V, is monitored, and as shown in FIG. 4, the charging voltage V gradually increases as the charging progresses, and the charging voltage reaches the inflection point (saturation point) V _C of the storage battery voltage. It is checked whether or not (S ₄ ). When the inflection point voltage is reached, the charging initial timer 24 is stopped, and the charging initial time T ₁ from the start of charging to the inflection point is obtained from the value of the timer 24 at this time. It is judged whether it is normal charge or equal charge (S ₅ ),
The total charging time T _A , which is preset as a constant in the ROM 41 in the one-chip MPU 24, and the charging rate K at the initial charging stage.
₁ , the late charging current K ₁ (normal charging), K ₃ (uniform charging), the initial charging time T ₁ measured by the timer 34, and the initial charging current I ₀ are used to calculate the latter charging current I ₁ by the following equation. Ask.

[0010] When the normal charging _{(S 6), I 1 =} K 2 I 0 T 1 / K 1 (T A -T 1) For equalizing charge _{(S 7), I 1 =} K 3 I 0 T 1 / K ₁ (T _a -T ₁₎ Incidentally, K ₁ is the ratio of the charge in the initial charge to the discharge amount, K _2, K ₃ is the ratio of discharge amount of the remaining charge amount required in the later charging, K ₁ , K ₂ and K ₃ are experimentally obtained. The discharge amount is the ratio of the discharged surface area to the rated capacity of the storage battery. T _A is determined by, for example, the time from the start of charging to the ideal completion of charging with respect to the average discharge amount. Normal charge is about 110 to 115% of the discharge amount, and uniform charge is about 125% of the discharge amount. In short, the late charging current I ₁ is set in proportion to the measured initial charging time T ₁ .

The calculated late charging current I ₁ and charging voltage are output from the D / A converter of the one-chip MPU 24 to the voltage / current control circuit 35 to throttle the base current of the transistor 18 to start the latter charging. . In the latter half of charging, the liquid temperature X _{2 of the} storage battery is constantly measured by the thermistor 36, and the liquid temperature X ₂ and the liquid temperature X ₁ immediately after the start of charging are measured.
The temperature rise ΔX ₁ (= X ₂ −X ₁ ) obtained from
This rise in temperature constantly monitors whether or not it is above a predetermined value (S _8). When the temperature rise exceeds a predetermined value, the storage battery 22
It is determined that the chemical reaction in ( ₁ ) is active and a large amount of gas is generated, and the charging current I ₁ is reduced (S ₉ ). That is, I ₁ is changed in inverse proportion to the liquid temperature. It is monitored whether or not the count time of the charge timer 33 becomes equal to the total charge time T _A (S ₁₀ ),
If it is not full charge time T _A returns to the step S ₈ is, at the full charge time T _A, stop signal to the voltage-current control circuit 35, the voltage-current control circuit 35 is nonconductive transistor 18 . After that, the one-chip MPU 24 controls the SSR relay 31 via the drive circuit 29, thereby further controlling the coil 32 of the electromagnetic contactor to open its contact 13 and disconnect the AC input to terminate the charging (S ₁₁ ). .
When the charging ON / OFF switch 28 is turned on again during charging, the one-chip MPU 24 performs the charging end operation.

In the embodiment of the invention of claim 1, the control of the embodiment of the invention of claim 2 shown in FIG. 1 omits the monitoring of the liquid temperature rise of the storage battery 22 in the latter stage of charging. That is, steps S ₈ and S ₉ are omitted, and step S ₆ or S ₇ is followed by step S ₁₀ . Further, in step S ₃ , the measurement of the storage battery liquid temperature is omitted, and in FIG. 2, the thermistor 36 and the resistor 38 are omitted.

The embodiment of the invention of claim 3 has the same configuration as that of FIG. 2, and an example of processing in the controller 23 thereof is shown in FIG.
The same step numbers are given to the parts corresponding to. However, in the invention of claim ₃ , the charging initial timer is not started in step S ₃ . Further, in step S ₆ , the late charging current I ₁ is simply set to, for example, 2/5 of the initial charging current I ₀ .
And In other words, conventionally, I ₁ was generally set to 1/3 of I ₀ , but in this embodiment, it is set to 1/3 or more of I ₀ . Step S ₇ also a value greater than the value of I ₁ in the conventional equalizing charge, determined by multiplying the constant ratio with respect to I _0. Others are the same as in FIG. That is, in the inventions of claims 1 and 2, the period T ₁ at the initial stage of charging is measured, and an appropriate late-stage charging current I ₁ is set accordingly to shorten the late-stage charging time T _2. Then, the latter charging current I ₁ is set to be larger than that in the conventional case, and the latter charging time T ₂ is shortened. Therefore, when the chemical reaction of the storage battery 22 becomes too active, this is detected by the liquid temperature rise, and the latter charging current I ₁ is detected. Is lowered.

[0014]

As described above, according to the first aspect of the invention, the initial charging time T ₁ is measured, and the late charging current I ₁ is determined in proportion to this time T ₁ , and the appropriate charging current I ₁ is always maintained. ₁ is obtained, and the late charging time T is generated without generating much gas.
₂ can be shortened. In the _{second aspect} of the invention, the late charging current I ₁ is further decreased in accordance with the rise in the liquid temperature of the storage battery in the late charging period T ₂ , so that the latter charging current I ₁ is set to be larger than the latter charging current I ₁ in claim 1. The charging current I ₁ can be set, and the late charging period T ₂ can be further shortened.

According to the invention of claim 3, the latter charging period T ₂
In the above, the increase in the liquid temperature of the storage battery is monitored, and when the liquid temperature rises, it is determined that the chemical reaction in the storage battery has become active, and the second-stage charging current I ₁ is decreased. The current I ₁ can be increased, the latter charging period T ₂ can be shortened accordingly, and a large amount of gas is not generated.

As described above, in each case, the latter charging period T ₂
Becomes shorter than before, and the total charging time T _A becomes shorter,
In addition, gas generation can be suppressed, the operating rate of devices (electric vehicles, etc.) that use this storage battery can be increased, and there is no risk of running out of liquid in the storage battery. Further, it is possible to prevent insufficient charging even for a storage battery having a large capacity.

[Brief description of drawings]

FIG. 1 is a flow chart showing an example of processing operation of a controller in the embodiment of the invention of claim 1.

FIG. 2 is a diagram showing a configuration of an embodiment of the invention of claim 2;

FIG. 3 is a flowchart showing an example of processing operation of a controller in the embodiment of the invention of claim 3;

FIG. 4 is a diagram showing a charging voltage and a charging current with time.

[Explanation of symbols]

 11 Input Terminal 12 AC Power Supply 21 Output Terminal 22 Storage Battery 23 Controller 24 One-chip Microcomputer 33 Charging Timer 34 Initial Charging Timer 36 Thermistor

Claims (3)

(57) [Scope of utility model registration request] 1. A storage battery is charged with a constant initial charging current,
When the charging voltage reaches the inflection point, a means for measuring the initial charging time from the start of charging to the inflection point of the charging voltage in an automatic charger that charges with a late charging current smaller than the initial charging current. And a means for setting the latter charging current in a proportional relationship with the measured initial charging time. 2. The automatic charger according to claim 1, further comprising means for measuring the liquid temperature of the storage battery and means for changing the latter charging current in an inversely proportional relationship with the measured liquid temperature. . 3. A storage battery is charged with a constant initial charging current,
When the charging voltage reaches an inflection point, in an automatic charger that charges with a later charging current smaller than the initial charging current, a means for measuring the liquid temperature of the storage battery, and the inversely proportional relationship with the measured liquid temperature An automatic charger characterized in that it is provided with means for changing the latter charging current.