JP2504014B2 - Battery charge control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a battery charge control device having a function of preventing overcharge of a vehicle-mounted battery.

[Prior Art] Conventionally, as an apparatus of this type, for example, Japanese Patent Laid-Open No. 48-9551
The one disclosed in Japanese Patent No. 0 is known. That is, as shown in FIG. 6, the charging characteristics of the battery are likely to be overcharged because the charging current increases as the temperature increases even if the charging voltage is the same. Focusing on this point, in the conventional technology, a temperature sensor for detecting the temperature of the battery is provided, and when it is determined that the temperature is equal to or higher than a predetermined temperature based on the detection signal from the temperature sensor, the output of the alternator is changed. Reduced to prevent overcharge.

[Problems to be Solved by the Invention] However, even if the device for preventing overcharge by the temperature of the battery as in the conventional technique, a new battery,
With a battery that has been used to some extent, there is a change in characteristics as shown in FIG. That is, as the battery is used, the charging current increases with the same charging voltage.
Therefore, in particular, when a battery used for a long period of time is charged at a high temperature, it is likely to be overcharged to run out of battery fluid, and when a new battery is charged at a low temperature, a problem of insufficient charging tends to occur. is there.

The present invention has been made to solve the above-mentioned problems of the conventional technology, and provides a battery charge control device capable of performing appropriate charging regardless of whether the temperature of the battery is high or low and the length of time the battery is used. To aim.

[Means for Solving the Problems] The present invention made to solve the above problems is the first aspect.
As shown in the figure, a battery charge control device C for controlling the amount of charge of a battery B connected to a generator A, a temperature detecting means D for detecting the temperature of the battery B, and a voltage for the battery B is detected. Voltage detecting means E, a current amount detecting means F for detecting a charging current amount to the battery B, a control section H for increasing / decreasing the charging amount from the generator A to the battery B, and detection signals of the above three detecting means. Determining means G for determining the control condition of the control section based on the above, and when the battery temperature detected by the temperature detecting means D is equal to or lower than a predetermined value, the determining means G uses the voltage detecting means E. When the detected battery voltage is less than or equal to a predetermined value, the first determination unit g1 that issues a charge command to the control unit H, and when the battery temperature is greater than or equal to the predetermined value, the amount of charging current detected by the current amount detection means F. Is controlled below a predetermined value A second determination unit g2 for issuing a charging instruction to the unit H;

Here, the generator A is an alternating current generator and a direct current generator,
Further, any type such as a synchronous generator capable of charging the battery may be used.

The temperature detecting means D is composed of a temperature detecting element such as a thermistor, and may be one that directly detects the temperature of the liquid of the battery or one that indirectly detects the temperature of the battery by detecting the temperature of the case of the battery. Including.

The control unit H that controls the amount of charge from the generator A to the battery B increases / decreases the power generation by interrupting the field current of the generator A, or the interrupter between the generator A and the battery B. Further, it may have any configuration such as one that controls the rotational driving force of the rotor of the generator A.

[Operation] In the battery charge control device C of the present invention, the amount of charging current from the generator A to the battery B is controlled by the control unit H. The command to the control unit H that controls the generator A is a temperature detection means D, a voltage detection means E and a current amount detection means F.
It is performed by the determination means G based on the detection signal from. In the determination means G, the first determination unit g1 and the second determination unit g2 make the determination as follows. That is, the first determination unit g2
When the detected temperature is equal to or lower than a predetermined value and the battery voltage is equal to or lower than the predetermined voltage, or when the detected temperature is higher than or equal to the predetermined value and the charging current is equal to or lower than the second determination unit g2, the control unit A A command to increase the charge amount is output to, and the charge amount is reduced at other times.

Therefore, since the battery B is charged only at a predetermined current or less even when the temperature is high, it is possible to suppress the liquid slippage of the battery B due to overcharging, and when the temperature is low, the internal resistance of the battery B increases. Since the amount of current is limited and whether to charge or not is commanded only by the battery voltage,
The charging current amount is not limited, and the charging control is efficiently performed.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a circuit diagram of a battery charge control device and its surroundings. Reference numeral 1 denotes an AC generator having an armature 3 and a field winding 5. A diode is provided on the output side of the AC generator 1. The in-vehicle battery 9 is connected via the rectifier 7. At the output terminal of this battery 9, a load 11
Is connected.

The output of the AC generator 1 is controlled by the regulator 13. The regulator 13 is a well-known microcomputer having a CPU 15, a ROM 17, a RAM 19, etc. and an A / D converter 2
3, input interface 25, output interface 27
And a battery voltage V1 connected to the anode side 9a of the battery 9 and a battery as the input signal of the electronic control unit 29. The detection signal Vt from the temperature sensor 31 detects the temperature of the battery 9. There is an output voltage V2 on the side of the AC generator 1 of the resistor 33 connected between 9 and the AC generator 1.

The output terminal of the electronic control unit 29 is connected to the base of the transistor 35. On the collector side of the transistor 35, the ignition switch 3 is sequentially arranged from the AC generator 1 side.
7, the lamp 39, and the diode 41 are connected, and the field winding 5 of the AC generator 1 is connected in parallel with the diode 41. The output side of the rectifier 7 is connected to the cathode side of the diode 41.

In the above configuration, when the rotor (not shown) of the AC generator 1 rotates as the engine (not shown) rotates,
Three-phase AC power is output from the armature 3 and rectified by the rectifier 7 to charge the battery 9. Then, in the electronic control unit 29, the detection signal Vt from the temperature sensor 31 and the battery voltage V1
And the charging current amount Ic obtained based on the output voltage V2 and the battery voltage V1 are input to the transistor 35
Control on and off. As a result, the output of the AC generator 1 is controlled by interrupting the current in the field winding 5, and the charge amount of the battery 9 is controlled.

Next, the control processing of the charge amount of the AC generator 1 executed based on the program stored in the ROM 17 of the electronic control unit 29 will be described with reference to the flowchart of FIG.

First, the detection signal Vt is read from the temperature sensor 31 to detect the temperature Th of the battery 9 (step 100). Next, it is judged whether or not the detected temperature Th is equal to or lower than a predetermined temperature (step 110), and when it is equal to or lower than the predetermined temperature Th, the process proceeds to step 120. After the battery voltage V1 is detected in step 120, the reference value f (Th) corresponding to the detected temperature Th is obtained based on the map shown in FIG. 4 (step 130). Next, it is determined whether or not the battery voltage V1 is smaller than the reference value f (TH) (step 140), and when it is smaller than the reference value f (Th), the transistor 35 is turned on and a current flows through the field winding 5. To increase the output of the AC generator 1 (step
150) On the other hand, when it is larger than the reference value f (TH), the transistor 35 is turned off to interrupt the field current and reduce the output of the AC generator 1 (step 160).

On the other hand, when it is determined in step 110 that the battery voltage V1 is equal to or higher than the predetermined temperature, the process proceeds to step 170, where the battery voltage V1 and the output voltage V2 are read. Next, from the above two voltages V1 and V2 and the resistance value of the resistor 33, the current value is calculated.
Find Ic (step 180). In the next step 190, it is determined whether or not this current value Ic is less than or equal to the predetermined current value β, and when it is less than or equal to the predetermined current value β, the transistor 35 is turned on to increase the output of the AC generator 1 (step 200). ,on the other hand,
When it is less than the reference current value β, the transistor 35 is turned off to decrease the output of the AC generator 1 (step 250).

According to the above-described embodiment, the battery 9 is charged when the battery voltage V1 is equal to or lower than the predetermined voltage when the battery temperature is low, and is equal to or lower than the predetermined current value when the battery voltage V1 is high temperature.
Therefore, even if the temperature of the battery 9 rises due to an increase in the outside temperature or a high load operation state for a long time, and the temperature of the battery 9 rises, the battery 9 is not charged with a current amount higher than a predetermined amount. Deterioration can be prevented and life can be extended.

Next, a modification of the program shown in FIG. 3 will be described with reference to FIG.

First, the battery temperature Th is read based on the detection signal Vt from the temperature sensor 31 (step 300), and further the battery voltage V1 is read (step 310). Next, based on the map of FIG. 4, the reference value f corresponding to the battery temperature Th
(Th) is calculated (step 320). Subsequently, it is determined whether or not the battery voltage V1 is larger than the reference value f (Th) (step 330), and when it is larger than the reference value f (Th),
In step 340, the transistor 35 is turned off to reduce the output of the AC generator 1. On the other hand, when it is smaller than the reference value f (Th), the process proceeds to step 350 to obtain the output voltage V2, and the current value Ic charged to the battery 9 is calculated from the output voltage V2 and the battery voltage V1 (step 360). , If the current value Ic is greater than or equal to the predetermined current value β (step 37
0), the transistor 35 is turned off to reduce the output of the alternator 1, while the transistor 35 is turned on to increase the output of the alternator 1 when the current value is below the predetermined current value Ic (step 380). . That is, in this flowchart, charging is performed when the battery voltage V1 and the charging current Ic are equal to or less than a predetermined value.

In the flowchart of FIG. 5, the temperature sensor 31 of the battery 9 can be eliminated and the configuration can be simplified by setting the reference value β obtained in step 370 to be slightly lower.

[Effects of the Invention] As described above, according to the present invention, charging is performed with an appropriate amount of current regardless of the temperature of the battery and the length of time the battery is used. Therefore, it is effective in reducing the battery fluid due to overcharge and preventing the deterioration of the battery, and it is possible to extend the life.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a basic configuration of the present invention, FIG. 2 is a circuit diagram showing a battery charge control device according to an embodiment of the present invention, and FIG. 3 is a flow chart executed in the same embodiment. FIG. 4 is a graph for obtaining a reference value used in the same embodiment, FIG. 5 is a flow chart processed in another embodiment, and FIGS. 6 and 7 are graphs for explaining a conventional technique. . A ... Generator, B ... Battery C ... Battery charge control device D ... Temperature detection means E ... Voltage detection means, F ... Current amount detection means G ... Judgment means g1 ... 1st judgment part, g2 ... 2nd judgment part 1 ... AC generator, 3 ... Armature 5 ... Field winding, 9 ... Battery 13 ... Regulator, 21 ... Electronic control unit V1 ... Battery voltage, V2 ... Output voltage

Claims (1)

(57) [Claims] 1. A battery charge control device for controlling the amount of charge of a battery connected to a generator, comprising: temperature detecting means for detecting the temperature of the battery; voltage detecting means for detecting the voltage of the battery; Amount detection means for detecting the amount of charging current to the battery, a controller for increasing / decreasing the amount of charge from the generator to the battery, and a determination for determining the control condition of the controller based on the detection signals of the three detecting means. When the battery temperature detected by the temperature detecting means is less than or equal to a predetermined value, the determining means is configured to charge the control unit when the battery voltage detected by the voltage detecting means is less than or equal to the predetermined value. A first determining unit for issuing an instruction, and a second determining unit for issuing an instruction for charging to the control unit when the battery temperature is equal to or higher than a predetermined value and the charging current amount detected by the current amount detecting unit is equal to or lower than the predetermined value. Charge control device of the battery, characterized in that it comprises a.