JPH02269423A - Charge controlling circuit - Google Patents

Abstract

PURPOSE:To prevent a fault of a charger main-body from being caused by detecting the fault of a temperature sensor when the output of a temperature detection circuit is of a specified value or less, and by stopping charging. CONSTITUTION:A temperature sensor 3 is fitted on a battery 2 in close contact with each other. When the battery 2 is set and charging is about to be started and when the output of a temperature detection circuit 6 is of a specified value or more, then it is detected that a fault is generated on the temperature sensor 3, and the charging is stopped by a CPU 5. In this case, a charging circuit 1 is controlled by the CPU 5, and its intent is displayed by a display circuit 8. As a result, incorrect charging can be prevented from being generated due to the fault of the temperature sensor 3, and accordingly, fault of the main body of the charger 1 can be prevented from occurring.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a charge control method that detects the state of charge of a secondary battery such as a Ni-Cd battery from the temperature of the battery and performs charging subwriting of the secondary battery. It is related to circuits.

[Prior art] In a charger, the voltage of a commercial power supply is stepped down by a transformer, etc., and then rectified and smoothed. A constant current circuit obtains a constant current from the rectified and smoothed output, and this constant current is used as a charging current for a thyristor, a transistor, etc. The battery is supplied to a secondary battery (hereinafter simply referred to as a battery) via a control element for charging.

One of the charging control methods for a pigeon house that charges a battery is to detect the temperature of the battery, determine the state of charge of the battery based on this temperature, and control charging. Incidentally, an invention related to this type of charging control circuit is described in Japanese Patent Application Laid-open No. 193518/1983 [Problem to be solved by the invention] Detected by the temperature sensor (diode) of the temperature detection circuit. However, for some reason, this temperature sensor may malfunction, failing to detect full charge, and charging may continue. At this time, overcharging occurs, and battery leakage occurs, making it impossible to secure the capacity of the battery. However, the user uses the battery thinking that it is fully charged, which causes problems such as the battery becoming unusable. Furthermore, battery leakage may cause damage to the charger body.

The present invention has been provided in view of the above-mentioned points, and provides a charging control circuit aimed at preventing unauthorized charging due to failure of a temperature sensor and preventing failure of the charger body due to this. It is something.

[Means for Solving the Problems] The present invention includes a control means that detects a failure of the temperature sensor and stops charging when the output of the temperature detection circuit is below a predetermined value.

Further, the present invention includes a control means that detects a failure of the temperature sensor when the output of the temperature detection circuit exceeds a predetermined value, and stops charging.

The device is equipped with a control means that detects a failure of the temperature sensor and stops charging when the output of the temperature detection circuit does not change for a predetermined period of time after the start of charging.

[Function] According to the present invention, when the output of the temperature detection circuit is less than or equal to a predetermined value, the control means detects a failure of the temperature sensor and stops charging.

Further, in claim 2, the control means detects a failure of the temperature sensor when the output of the temperature detection circuit is equal to or higher than a predetermined value;
I am trying to stop charging.

Furthermore, in a third aspect of the present invention, the control means detects a failure of the temperature sensor and stops charging when the output of the temperature detection circuit does not change for a predetermined period of time after the start of charging.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. The circuit configuration of the embodiment is shown in FIG. 1. The surface temperature of the battery 2 charged in the charging circuit 1 is detected by a temperature sensor 3 attached closely to the battery 2. Convert to voltage value according to temperature. The temperature sensor 3 is composed of a resistor Rs and a diode Ds.

In addition, the temperature sensor 3 and the amplifier circuit 7 form a temperature detection circuit 6.
It consists of The converted voltage value is the operational amplifier OP
1 and resistors R1 to R1, and is input to the A/D converter 4. The A/D converter 4 converts the input voltage value into a digital value, and the CPU 5
Enter. The CPU 5 calculates the temperature rise rate per unit time from the input data through arithmetic processing, and when the temperature rise rate exceeds a preset temperature rise rate, it determines that the battery is fully charged and controls the charging circuit 1. .

FIG. 2(a) shows the charging state of the battery 2, and FIG. 2(b) shows the surface temperature of the battery 2. The surface temperature of battery 2 is
It gradually increases until it approaches 100%, and increases rapidly after it passes 100%.

Next, Example 1 will be explained. The relationship between the temperature detected by the temperature sensor 3 and the voltage is shown in FIG. 3(a), and
The output of the temperature detection circuit 6 at that time is shown in the same figure (b).The output of the temperature detection circuit 6 is controlled by the volume VR, VR2, for example, 0°5■ at 0°C and 4.5■ at 100°C. Adjust to. The operating temperature range is currently 0°C to 100°C.

Here, when the temperature sensor 3 has a failure such as disconnection or disconnection of the temperature sensor 3 for some reason (open mode failure), the output voltage Vs of the temperature sensor 3 is pulled up by the resistor R7. becomes the maximum. In other words, the output of the temperature detection circuit 6 becomes 0.5V or less. Therefore, when battery 2 is set and you are about to start charging,
When the output of the temperature detection circuit 6 is less than a predetermined value, it is detected that the temperature sensor 3 is malfunctioning, and charging is stopped. That is, when the output voltage of the temperature detection circuit 6 is below a predetermined value, the CPU 5 controls the charging circuit 1 based on the data input via the A/D converter 4 to stop charging. At the same time, the display circuit 8 displays a message to that effect. This state is shown in the flowchart of FIG. Note that the CPU 5 constitutes a control means that detects a failure of the battery 2 and stops charging.

Next, Example 2 will be explained. Since the temperature sensor 3 is attached closely to the battery 2 as described above,
When the battery 2 leaks, the temperature sensor 3 is short-circuited at both ends (complete short-circuit mode failure), and the output voltage Vs of the temperature sensor 3 becomes 0. In other words, the output of the temperature detection circuit 6 is 4.5■ or more. Therefore, when battery 2 is set and you are about to start charging,
When the output of the temperature detection circuit 6 is equal to or higher than a predetermined value, it is detected that the temperature sensor 3 is malfunctioning, and charging is stopped. In this case as well, the CPU 5 controls the charging circuit 1 and the display circuit 8 displays a message to that effect. The state in this case is shown in the flowchart of FIG.

Also, as shown in Fig. 4, set the battery 2 and
The D converter 4 samples the output of the temperature detection circuit 6,
If the rate of increase in the output voltage, that is, the rate of increase in temperature is within the range of the above-mentioned predetermined value and the predetermined time has elapsed, the charging is completed.

Next, Example 3 will be explained. That is, this is a case where only the diode Ds of the temperature sensor 3 is short-circuited. When the diode Ds of the temperature sensor 3 is short-circuited, the output voltage Vs of the temperature sensor 3 is always constant. Therefore,
When the output of the temperature detection circuit 6 does not change within a predetermined period of time after the battery 2 is set and charging is started, a malfunction of the temperature sensor 3 is detected, charging is stopped, and a display is displayed. I have to. This state is shown in the flowchart of FIG.

That is, after setting the battery 2, the CPU 5
The output voltage from the D converter 4 is stored as an initial value, the next data is sampled by the A/D converter 4 after a predetermined time has elapsed, and if the rate of increase is greater than or equal to the predetermined value, the charging circuit 1 is controlled. to complete charging. However, if the previous data and the current data are the same after a predetermined period of time has elapsed, there is no change in the rate of increase, so the CPU 5 stops charging and displays on the display circuit 8 that there is a failure.

In the above-described embodiments 1 to 3, when a malfunction is detected in the temperature sensor 3, the display circuit 8 displays this fact, so the user can determine whether the charger is malfunctioning or the battery 2 or battery back. It is possible to know if there is a failure in the battery 2, and to avoid accidentally using a battery 2 with no capacity. Therefore, the failure of the temperature sensor 3 is notified to the user, leading to improved satisfaction.

It goes without saying that the methods of Examples 1 to 3 may be combined arbitrarily.

[Effects of the Invention] As described above, the present invention includes a control means that detects a failure of the temperature sensor and stops charging when the output of the temperature detection circuit is below a predetermined value.
It is possible to detect a failure in the temperature sensor and stop charging when the output of the temperature detection circuit is below a predetermined value.This prevents unauthorized charging due to failure of the temperature sensor and prevents damage to the charger itself. This has the effect of improving the reliability of the charger.

In addition, since the device is equipped with a control means that detects a failure of the temperature sensor and stops charging when the output of the temperature detection circuit is above a predetermined value, the control means can control the temperature sensor when the output of the temperature detection circuit is above a predetermined value. It is possible to detect a failure in the temperature sensor and stop charging, thereby preventing unauthorized charging due to failure of the temperature sensor, thereby preventing failure of the charger itself, and improving the reliability of the charger. It has the effect that it can.

Furthermore, since the device is equipped with a control means that detects a failure of the temperature sensor and stops charging when the output of the temperature detection circuit does not change for a predetermined period of time after the start of charging, Temperature sensor failure can be detected and charging can be stopped when the output of the temperature sensor circuit does not change over time. This prevents unauthorized charging due to temperature sensor failure, thereby preventing the charger from malfunctioning. This has the effect of preventing this problem and improving the reliability of the charger.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram of an embodiment of the present invention. Figure 2 is a diagram showing the surface temperature and charge amount of the same battery as above,
FIG. 3 is an explanatory diagram of the same operation as above, and FIG. 4 is an illustration of the same embodiment 1 as above.
2, and FIG. 5 is a flow diagram of Embodiment 3 of the same. 2 is a secondary battery, 3 is a temperature sensor, and 6 is a temperature detection circuit. Agent Patent Attorney Ishi 1) Chief 7 Figure 2 Figure 3 (a) (b) Figure 4 Figure 5

Claims (3)

[Claims] (1) In a charging control circuit that is equipped with a temperature detection circuit that measures the temperature of a secondary battery with a temperature sensor and outputs a voltage corresponding to the temperature, and that controls charging based on the detected output voltage, the output of the temperature detection circuit is A charging control circuit comprising a control means for detecting failure of a temperature sensor and stopping charging when the temperature is below a predetermined value. (2) In a charging control circuit that is equipped with a temperature detection circuit that measures the temperature of the secondary battery with a temperature sensor and outputs a voltage corresponding to the temperature, and that controls charging based on the detected output voltage, the output of the temperature detection circuit is A charging control circuit comprising control means for detecting failure of a temperature sensor and stopping charging when the temperature exceeds a predetermined value. (3) In a charging control circuit that is equipped with a temperature detection circuit that measures the temperature of the secondary battery with a temperature sensor and outputs a voltage corresponding to the temperature, and that performs charging control based on the detected output voltage, a predetermined period of time after the start of charging . A charging control circuit comprising a control means for detecting a failure of a temperature sensor and stopping charging when the output of the temperature detection circuit does not change.