JPH05144481A - Storage battery condition sensing device - Google Patents

Abstract

PURPOSE:To sense accurately the temp. and level of a storage battery electrolytic solution using a single device and eliminate the necessity for any complicated wirings. CONSTITUTION:The positive electrode of a diode 5 for temp. sensing, a resistance 4 for adjusting the diode current, a current limiting resistance 3, and a sensing electrode 2 are connected in series in the sequence as named. A constant voltage element 6 is connected in parallel in regular direction with the serial circuitry of the diode 5 and resistance 4. The first output line 7 consists in a grounding lead led out of the negative electrode of the diode 5, while the second output line 8 is led out of the positive electrode of the diode 5 to serve for emitting the results from sensing of the solution level and the temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage battery state detecting device.

[0002]

2. Description of the Related Art Many proposals have been made for devices for detecting the electrolyte level and temperature of a storage battery. Most of these are obtained by separating the liquid level detecting device and the temperature detecting device. As a liquid level detecting device, a liquid level detecting electrode is mainly inserted into an electrolytic solution and the liquid level is detected by detecting the presence or absence of a sensor current flowing through this electrode.
In addition, as the temperature detecting device, it is mainly that the temperature is detected by a thermistor or the temperature is detected by a forward drop of a diode. Especially when measuring the electrolyte temperature,
In most cases, a diode that is more compact than the thermistor is built in the lower end of the liquid stopper.

[0003]

When the liquid level and temperature of the storage battery electrolyte are detected and displayed on the driver's seat of the automobile,
If the liquid level detector and the temperature detector are separate,
Wiring of at least 3 to 4 sensor lines is required between the two detectors and the storage battery driver's seat. As the number of wirings increases, not only the reliability of the detection device decreases but also the number of wiring man-hours increases. In particular, it is a top priority that the detection device used in an automobile or the like has high reliability and is inexpensive. In the past, although some storage battery state detection devices that combine a liquid level detection device and a temperature detection device have been introduced, their detection accuracy is poor and they have not been put into practical use.

The present invention has been made to solve the above problems, and its purpose is to
It is an object of the present invention to provide a storage battery state detection device that can accurately detect the liquid level and temperature of a storage battery electrolyte with a single device and does not require complicated wiring.

[0005]

SUMMARY OF THE INVENTION Therefore, a detection electrode, a current limiting resistor, a temperature detecting diode, a temperature detecting diode, a current adjusting resistor, a constant voltage element, and two output lines are provided to detect the temperature. The diode, the diode for temperature detection, the resistance for current adjustment, the resistance for current limiting, and the detection electrode are the positive electrode of the temperature detection diode, the resistor for current detection diode current adjustment, the current limiting resistance, and the detection electrode connected in series in this order. The constant voltage element is connected in parallel in the forward direction to the series circuit of the temperature detecting diode and the temperature detecting diode current adjusting resistor, and the first output line is derived from the negative electrode of the temperature detecting diode. The second output line is derived from the positive electrode of the temperature detecting diode and is used for liquid level detection and temperature detection output. It is intended to solve the above problems by location, and.

[0006]

EXAMPLES The present invention will be described in detail below with reference to specific examples. FIG. 1 is a schematic diagram in which the storage battery state detection device according to the present invention is used for a lead storage battery for an automobile. In the figure, reference numeral 1 denotes a plug, which is mounted on a storage battery liquid port or a storage battery lid. Reference numeral 2 is a detection electrode, the tip of which is exposed from the plug body so as to be in direct contact with the electrolytic solution of the second cell from the negative electrode terminal. 3 is a current limiting resistor (resistance value Rx), 4
Is a resistor for temperature detection diode current adjustment (resistance value Ry
) 5 is a temperature detecting diode, and 6 is a constant voltage element. Reference numeral 7 is a first output line derived from the negative electrode of the temperature detecting diode 5, which is an earth line. In this embodiment, the storage battery is connected to the negative terminal, but it may be directly grounded to the vehicle body. A second output line 8 is derived from the positive electrode of the temperature detecting diode 5 and is used for liquid level detection / temperature detection output. The temperature detecting diode 5, the temperature detecting diode current adjusting resistor 4, the current limiting resistor 3 and the detecting electrode 2 are the positive electrode of the temperature detecting diode 5, the temperature detecting diode current adjusting resistor 4, the current limiting resistor 3, The detection electrodes 2 are connected in series in this order, and the constant voltage element 6 is connected in parallel in the forward direction to the series circuit of the temperature detection diode 5 and the temperature detection diode current adjustment resistor 4. In the present embodiment, the detection electrode 2, the current limiting resistor 3, the temperature detection diode 5, the temperature detection diode current adjustment resistor 4, and the constant voltage element 6 except the tip portion of the detection electrode 2, the plug body 1. It is molded inside. The constant voltage element 6 is the detection electrode 2
Depending on the position of the insertion cell of. In FIG. 1, the detection electrode 2
Is inserted in the second cell, but when it is inserted in the fifth cell, a 5V Zener diode is suitable as the constant voltage element. Reference numerals 9 and 10 denote plugs that connect the display unit and the detection unit, and an integrated 2P plug may be used.

With respect to the potential level of the storage battery electrolyte, when the storage battery is left standing, the electrolyte of the second cell from the negative electrode terminal of the storage battery shows about 2V. However, this potential level changes in proportion to the terminal voltage of the storage battery due to charging and discharging. The maximum charging voltage is approximately 15V for automobile storage batteries
Therefore, the fluctuation range of the storage battery voltage can be considered to be 12 to 15V. Since the fluctuation range of the electrolyte potential of the second cell also changes at the same ratio as above, the fluctuation range of the second cell potential is 2 to
It becomes 2.5V. In FIG. 1, when the constant voltage element 6 is not present, the current I flowing through the temperature detecting diode 5
s changes within the range shown by the following equation. (2.0−about 0.6V) / (Rx + Ry) × Is <(2.5−about 0.6V) / (Rx + Ry) The constant 0.6V in the above equation indicates the forward drop of the temperature detecting diode 5. 1.4 <Is (RX + RY) <1.9 1 <Is (RX + RY) /1.4 <1.9 / 1.4 = about 1.36 Rx and Ry are fixed resistors, so the temperature detection diode 5
The change width of the current Is flowing in the range is 100 to 136%.

FIG. 2 is a diagram showing how the diode forward drop changes with temperature change. If the current Is flowing in the temperature detecting diode 5 is constant,
The diode forward drop is perfectly inversely proportional to temperature.
Further, as can be understood from the figure, when Is changes in the increasing direction, the diode forward drop increases, and when Is decreases, the diode forward drop decreases. When the storage battery is open, the potential level of the detection electrode is 2 V and Is is
2.5V when the current is set to 1mA and when charged
When calculated, referring to Figure 2 as mentioned above,
At the temperature of 20 ℃, the diode drop is 0.64V and Rx +
Since Ry = 1.36K ohms, at a charging voltage of 2.5V, (2.5-0.64) /1.36 ohms, Is = 1.
It becomes 36 mA, the forward drop increases by about 0.01 V, and an error of about 6 ° C occurs in the temperature conversion display. In the present invention, in order to eliminate the cause of such an error occurrence, the constant voltage element 6 stabilizes the Is current flowing through the temperature detecting diode 5 to a constant value, and the constant voltage element 6 functions as the diode 5 and the temperature detecting diode current adjusting resistor 4. Are connected in parallel to the series circuit. When the detection electrode 2 is inserted into the second cell from the negative electrode terminal of the storage battery, since the electrolytic solution potential is 2V, a constant voltage element lower than this voltage is suitable for establishing the voltage of the constant voltage element 6. The constant voltage element 6 of FIG. 1 constitutes a constant voltage of about 1.8 V from the forward drop of three diodes (1.8 V).
Although it can be processed with one element by using the Zener diode of, the 1.8V Zener diode uses a diode because there are many variations in voltage). In this case I
When s is set to 1 mA, RY = 1200 Ω from the following equation. [1.8V-0.6V (diode forward drop)] / RY = 1mA Also, the current limiting resistor 3 flows a current that is 2 to 3 times the Is current in order to establish the voltage of the constant voltage element 6. There is a need. Therefore, the resistance value of the current limiting resistor 3 is about 50 to 100 Ω.

When the detection electrode 2 is inserted into the fifth cell from the negative electrode terminal of the storage battery, the electrolytic solution potential becomes 8V,
As the constant voltage element 6, it is desirable to adopt a Zener diode around 5V which is stable against temperature changes. The resistance value of Ry in this case is RY = (5V-0.6V) / RY = 1mA when Is = 1mA
It becomes 4.4 KΩ. By connecting the constant voltage element 6 in parallel with the temperature detecting diode in this way, the Is current can be kept constant even if the storage battery voltage changes. As a result, accurate temperature output characteristics can be obtained.

The second output line 8 sends an OUT signal to the display section or the control section through the plug 10. When the liquid level is normal, the Is current flows and a forward drop voltage is established in the diode 5, and the OUT signal is obtained as the characteristic shown in FIG. For example, when the time when the OUT signal becomes 0.56 V or lower is detected, it indicates that the battery temperature of the storage battery has become 60 ° C. or higher (point A in FIG. 2). Further, when the OUT signal becomes 0 V, the Is current is 0, that is, the detection electrode 2 is detached from the electrolytic solution, and it is possible to determine the reduced state of the electrolytic solution. Figure 2
The reason why the liquid level detection voltage point B is set to 0.3 V is that the output terminal OUT generated by the leak current from the detection electrode 2
This is to prevent operation due to a minute voltage.

[0011]

According to the storage battery state detecting device having the above-described structure, it is possible to output an analog or digital signal for temperature and a digital signal for liquid level with one output line. Is. As described above, cost and reliability are the top priorities when developing a storage battery state detection device. According to the storage battery state detection device of the present invention, the liquid level and temperature of the storage battery electrolyte can be accurately detected by one device, and moreover, complicated wiring is not required, and its effect is great.

[Brief description of drawings]

FIG. 1 is a schematic diagram in which a storage battery state detection device according to the present invention is used in a lead acid battery for an automobile.

FIG. 2 is a diagram showing the relationship between temperature change and diode forward drop.

[Explanation of symbols]

 1 Plug 2 Liquid Level Detection Electrode 3 Current Limiting Resistor 4 Temperature Detection Diode Current Adjustment Resistor 5 Temperature Detection Diode 6 Constant Voltage Element 7 First Output Line 8 Second Output Line

Claims (1)

[Claims] 1. A detection electrode (2), a current limiting resistor (3), a temperature detecting diode (5), a temperature detecting diode current adjusting resistor (4), a constant voltage element (6) and two output lines. (7, 8), the temperature detecting diode (5), the temperature detecting diode, the current adjusting resistor (4), the current limiting resistor (3) and the detecting electrode (2) are the temperature detecting diode. The positive electrode of (5), the temperature detecting diode current adjusting resistor (4), the current limiting resistor (3) and the detecting electrode (2) are connected in series in this order, and the constant voltage element (6) is used for temperature detecting. The diode (5) for temperature detection and the resistance (4) for temperature detection diode current connection are connected in parallel in the forward direction, and the first output line (7) is connected to the temperature detection diode (5). The second output line (8) is the ground line derived from the negative electrode, and the second output line (8) is the temperature line. Be those derived from the positive electrode diode (5) out, it is for the liquid level detection and temperature detection output, the storage battery state detecting device.