JPH0733563Y2 - Battery charger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a battery charger.

[Conventional technology]

An electric vehicle such as an electric vehicle is generally equipped with an electric motor and a storage battery as its power source.

As a charging device for charging the storage battery, for example, while controlling the charging current to the storage battery to a predetermined value, when the terminal voltage of the storage battery reaches a predetermined value, start timing from that point, There are some that end charging when a predetermined time has passed. In this case, as charging time,
The time is set so that the storage battery can be fully charged at room temperature (15 ° C to 25 ° C) without shortage.

[Problems to be solved by the invention]

However, the battery becomes insufficiently charged at low temperatures, while being overcharged at high temperatures. For this reason, the sensor such as the thermistor is used to correct the charging time with respect to the battery temperature. However, the sensor circuit is not necessarily completely equipped, and the correction is excessive in the case of a thermistor disconnection accident or the like. Was always accompanied.

[Purpose of device]

The object of the present invention is to improve the inconvenience of the conventional example, and in particular, it is possible to appropriately correct the charging time in response to changes in the external temperature, and even when the thermistor does not function, a predetermined charging time is obtained. It is to provide a battery charging device capable of setting the battery.

[Means for solving problems]

In view of this, the present invention includes a charging circuit for a battery, a timer circuit that determines the charging time of the battery by this charging circuit, and a charging voltage control circuit that is activated by the output of this timer circuit. Is equipped with a charging time correction circuit. This charging time correction circuit includes a first series resistance circuit formed by a first resistor on the power supply side, a thermistor for detecting battery temperature, and a second resistor on the ground side,
The thermistor and the second resistor are connected in parallel to the series circuit portion of the second resistor, and the second resistor circuit is formed by the third resistor and the switch circuit. The operation level of the switching circuit is set to the same level as the ground side terminal of the thermistor, and the potential change at the outer end of the second series circuit is sent to the timer circuit as a charging time setting signal. This aims to achieve the above-mentioned object.

[Example of device]

An embodiment of the present invention will be described below with reference to FIGS.

The embodiment shown in FIGS. 1 and 2 operates by being charged with the charging circuit 1 for the battery, the timer circuit 3 for determining the charging time of the battery 2 by the charging circuit 1, and the output of the timer circuit 3. The charging voltage control circuit 4 is provided.

The timer circuit 3 is provided with a charging time correction circuit 5. This charging time correction circuit 5 is the first resistor on the power supply side.
The first series resistance circuit 6 formed by R ₁ , the thermistor circuit section 6A, and the second resistor R ₂ on the ground side, and the series circuit section of the thermistor circuit section 6A and the second resistor R ₂ are connected in parallel. And a second series resistor circuit 7 formed by a _third resistor R ₃ and a switch circuit 7A.

Here, the operation level of the switching circuit 7A is the thermistor.
Set to the same level as the ground side terminal of 6B. And
The potential change at the outer end of the second series circuit 7 is sent to the timer circuit 3 as the charging time setting signal S.

The charging circuit 1 includes an AC power supply 1A, a transformer 14, a rectifier circuit 15, and a thyristor 16. The AC power supply 1A is applied to the primary side of a transformer 14 via a main switch 12 and a fuse 13, and the secondary side output of this transformer 14 is a rectifier circuit 15
Has been rectified by.

The positive output terminal of the rectifier circuit 15 is connected to the positive charging terminal 17 via the thyristor 16, and its negative output terminal is connected to the negative charging terminal 19 via the shunt resistor 18 for current detection. There is. The positive side terminal and the negative side terminal of the battery are connected to the positive side charging terminal 17 and the negative side charging terminal 19, respectively.

Further, the charging voltage control circuit 14 includes a rectifier circuit 15 and a thyristor.
The voltage at the interconnection terminals of 16 and the current applied to the shunt resistor 18 are respectively detected, and the on / off state of the thyristor 16 is controlled so that each becomes a preset predetermined value. Further, the charging voltage control circuit 14
When the charge stop signal ST is output from the timer circuit 13, the voltage control operation for charging is ended. The timer circuit 3 monitors the charging voltage, and when the value reaches a predetermined charging voltage, starts the time counting operation, and when the value ends, outputs the charging stop signal ST to the charging voltage control circuit 4. .

The thermistor circuit portion 6A in the first series circuit 7 of the charging time correction circuit 5 is composed of a thermistor 61 and a separation switch 62. Therefore, by operating the separation / connection switch 62, the thermistor 61 can be cut or joined to the thermistor circuit section 6A at any time. The switching circuit 7A in the second series circuit 7, the transistors of the emitter-grounded T _r1 and T _r2
Is configured as shown in FIG. In this case, one transistor T _r1 is directly energized by the power source V _cc via the resistor R ₄ .

Next, the operation of the above embodiment will be described.

First, consider the case where the separation / connection switch 62 is turned on and the thermistor 61 is in “contact” with the circuit. In this case, the switching circuit 7A is in the off state. Therefore, the output level of the charging time setting signal S is the constant voltage V in FIG.
It becomes the latter value when _cc is _divided by “first resistor R ₁ ” and “thermistor 61 + second resistor R ₂ ”, and this changes the resistance due to the temperature of the battery 2 part equipped with the thermistor 61. Will change according to. As a result, the charging time for the timer is automatically adjusted according to the temperature change of the battery.

On the other hand, consider a case where the thermistor 61 is removed from the circuit by the separation / connection switch 62 or due to a defective joint of the thermistor 61. In this case, the switch circuit 7A is automatically turned on (OH), and the "first resistor R _1" and the charging of the latter constant value timer when divided by "the third resistor R _3" It becomes the time setting value. The constant value in this case is specified in advance as an output value corresponding to the standard charging time.

As described above, in the present embodiment, not only is it possible to appropriately correct the charging time according to the battery temperature by the action of the thermistor 61, but also when the thermistor 61 does not function due to a disconnection accident, etc. A constant charging time setting signal S can be automatically output by the resistor 6A of 1 and the third resistance of the second series circuit 7 and 7A, and the battery 2 is installed in a place where the temperature changes little. In that case, there is an advantage that the temperature adjustment by the thermistor 61 can be eliminated by operating the separation / contact switch 62, and the usage method can be changed according to the application.

[Effect of device]

As described above, according to the present invention, the operation of the first series resistance circuit having the thermistor makes it possible to appropriately correct the charging time according to the battery temperature, and to operate when the thermistor has a disconnection accident or the like. Due to the action of the second series resistance circuit having the switching circuit, the setting signal for the timer corresponding to the standard charging time is immediately output even when the thermistor has a disconnection accident, which allows stable charging of the battery. Thus, it is possible to provide a practical battery charger that is not possible in the past.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing an example of a charging time correction circuit in FIG. 1 ... Battery charging circuit, 2 ... Battery, 3 ... Timer circuit, 4 ... Charging voltage control circuit, 5 ... Charging voltage correction circuit, 6
... 1st series resistance circuit, 6A ... thermistor circuit part, 7 ... 2nd series resistance circuit, 7A ... switch circuit, R ₁ ... 1st resistor, R ₂ ... 2nd resistor, R ₃ ... 3 resistors.

Claims (1)

[Scope of utility model registration request] 1. A charging circuit for a battery, a timer circuit which determines a charging time of a battery by the charging circuit, and a charging voltage control circuit which is operated by being biased by an output of the timer circuit. A charging time correction circuit is provided side by side, and the charging time correction circuit includes a first series resistor formed by a first resistor on the power supply side, a thermistor for detecting battery temperature, and a second resistor on the ground side. Circuit and a second series resistance circuit formed in parallel with the series circuit part of the thermistor and the second resistor and formed by a third resistor and a switch circuit, and the operating level of the switching circuit. Is set to the same level as the ground side terminal of the thermistor, and the potential change at the outer end of the second series circuit is sent to the timer circuit as a charging time setting signal. Battery charging apparatus wherein the Komu Ri.