JP2011169789A - Storage battery state detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To output the information liquid temperature and liquid level with one output signal line 13 and to prevent erroneous detection even when a potential difference occurs in a minus line of a storage battery. <P>SOLUTION: The storage battery state detector 10 includes a liquid level detection electrode 11, a temperature detection resistor 12, and one output signal line 13. The liquid level detection electrode 11 is connected to the output signal line 13 through second and third switching elements 20, 21 and a second constant-current source 22. A first constant-current source 14 is connected to the output signal line 13 through a first switching element 16 turned on and off by an output of an oscillator circuit 15. The oscillator circuit 15 is composed of a timer IC 23 and a time constant setting circuit 24 connected to the timer IC 23 to set the on-off timing of a switch for capacitive discharge built in the timer IC 23. The temperature detection resistor 12 constitutes a part of the time constant setting circuit 24, and a power supply 17 of the timer IC 23 is powered from a storage battery 18. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a storage battery state detection device, and more particularly to a storage battery state detection device that detects a liquid temperature and a liquid surface state of a storage battery.

  In a vehicle, a storage battery is mounted as a power source for electrical components. In addition, electric vehicles and hybrid vehicles are also equipped with a storage battery for the power source of the driving motor. The life of storage batteries, especially lead batteries, is greatly affected by the quality of maintenance, and it becomes impossible to charge when the electrolyte is exhausted and the electrode plate is exposed. Therefore, the electrode plate is not exposed by always checking the liquid level of the storage battery. Need to hold on. Further, when the liquid temperature of the storage battery becomes high, the storage battery is adversely affected. Therefore, it is necessary to monitor the liquid temperature so that the liquid temperature does not become high.

  Conventionally, a storage battery state detection device has been proposed in which the liquid level and temperature of the storage battery electrolyte can be detected with a single device, and the temperature detection output and the liquid level detection output can be performed with a single output line (see Patent Document 1). ). As shown in FIG. 5, the storage battery state detection device described in Patent Document 1 is provided with a detection electrode 52, a current limiting resistor 53, and a temperature detection diode 55 on a plug 51 mounted on a storage battery liquid port or a storage battery lid. The temperature detection diode current adjustment resistor 54 and the constant voltage element 56 are molded except for the tip of the detection electrode 52. The temperature detecting diode 55, the temperature detecting diode current adjusting resistor 54, the current limiting resistor 53, and the detecting electrode 52 are the anode of the temperature detecting diode 55, the temperature detecting diode current adjusting resistor 54, the current limiting resistor 53, The detection electrodes 52 are connected in series in this order. The constant voltage element 56 is connected in parallel in the forward direction to a series circuit of a temperature detecting diode 55 and a temperature detecting diode current adjusting resistor 54. The first output line 57 led out from the cathode of the temperature detection diode 55 is a ground line, and is connected to the negative terminal of the storage battery via the plug 59. The second output line 58 derived from the anode of the temperature detection diode 55 is for liquid level detection / temperature detection output, and is connected to the display unit via the plug 60. Then, the temperature of the storage battery is detected by the output voltage from the second output line 58, and when the output voltage becomes 0V, it is detected that the detection electrode 52 is detached from the electrolytic solution, that is, the liquid level is abnormal. It is supposed to be.

Japanese Patent Laid-Open No. 5-144481

  By installing the storage battery state detection device of Patent Document 1 in a storage battery mounted on a vehicle, the liquid temperature and liquid level information of the storage battery can be sent to the vehicle side by one second output line 58. However, since a load such as a motor is connected to the storage battery mounted on the vehicle, a potential difference may occur in the negative line of the storage battery. And since the storage battery state detection apparatus of patent document 1 sends the information of a liquid temperature and a liquid level with the voltage of 0V-several V, there exists a possibility that a misdetection may arise. Moreover, in the storage battery state detection device of Patent Document 1, the liquid temperature detection is performed in a state where the liquid temperature detection unit, that is, the series circuit of the current limiting resistor 53, the temperature detecting diode current adjusting resistor 54, and the temperature detecting diode 55 is disconnected. Of course, the liquid level cannot be detected.

  The present invention has been made in view of the above-described conventional problems, and the object thereof is to output information on the liquid temperature and the liquid level with a single output signal line, and to provide a potential difference on the negative line of the storage battery. An object of the present invention is to provide a storage battery state detection device that can prevent erroneous detection even if the occurrence of a battery failure occurs.

  In order to achieve the above object, an invention according to claim 1 is a storage battery state detection device including a liquid level detection electrode, a temperature detection resistor, and one output signal line. The output signal line is supplied with a current flowing through the liquid level detection electrode and a current flowing from a constant current source via a switching element that is controlled to be turned on / off by the output of the oscillation circuit. The temperature detection resistor is used for a circuit that sets an oscillation cycle, and the oscillation circuit power source and the constant current source are from a storage battery to which a storage battery state detection device is mounted. Power is supplied.

  The storage battery state detection device of the present invention is used in a state where the liquid level detection electrode is in contact with the electrolytic solution of the storage battery. Until the liquid level of the storage battery (the liquid level of the electrolytic solution) is abnormal, that is, until the liquid level detection electrode is detached from the electrolytic solution, current flows from the liquid level detection electrode to the output signal line, When the liquid level becomes abnormal, the flow of current from the liquid level detection electrode is lost. Also, the temperature detection resistor is involved in the pulse output cycle of the oscillation circuit, that is, the oscillation cycle setting, and the resistance value of the temperature detection resistor changes depending on the temperature of the temperature detection resistor, that is, the liquid temperature of the storage battery. The on-time or off-time of the element changes, that is, the time when the current value flowing through the output signal line increases or the time when the current value flowing through the output signal line decreases. As a result, it becomes possible to detect whether or not the liquid temperature is an abnormal temperature based on, for example, a time interval in which the current flowing through the output signal line becomes a certain value or more. That is, the liquid temperature and the state of the liquid level are not detected based on the output voltage of the output signal line, but are detected based on the value of the current flowing through the output signal line. Therefore, liquid temperature and liquid level information can be output by a single output signal line, and erroneous detection can be prevented even if a potential difference occurs in the negative line of the storage battery.

  According to a second aspect of the present invention, in the first aspect of the invention, the unstable multivibrator includes a timer IC and an external connection connected to the timer IC for setting the on / off timing of the timer IC. A time constant setting circuit comprising an attaching resistor and a capacitor, and the temperature detection resistor forms part of the time constant setting circuit, and the constant current source is determined by the value of the temperature detection resistor. The time during which the current from is supplied to the output signal line varies. In this invention, the pulse output period of the oscillation circuit can be set by an external resistor and capacitor including a temperature detection resistor externally attached to the timer IC, and a desired output can be obtained using a commercially available timer IC. An oscillation circuit having a period can be easily configured.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, at least one of a current flowing through the oscillation circuit and a current flowing through the power source is supplied to the output signal line. In the present invention, even when the temperature detection resistor is disconnected, it is possible to detect the presence or absence of disconnection of the output signal line based on the presence or absence of current flowing through at least one of the oscillation circuit and the power supply.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the constant current source is a first constant current source, and further includes a second constant current source, The liquid level detection electrode is connected to the output signal line through the second constant current source. In the present invention, it is possible to detect the presence or absence of abnormality of the liquid level detection electrode based on the current flowing from the second constant current source.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the power source and the first constant current source are connected to the storage battery at a location lower than the potential of the liquid level detection electrode via a wiring. Electrically connected, the switching element as the first switching element, a second switching element is connected between the liquid level detection electrode and the wiring, and the wiring and the output signal line are the second Are electrically connected via a third switching element that is turned on when the switching element is turned on and the second constant current source, and the second switching element and the third switching element are electrically connected to each other. Turns on when a current flows through the surface detection electrode.

  In this invention, the liquid temperature state is detected in the same manner as in the case of the invention described in claim 4. On the other hand, when the liquid level is abnormal, the value of the current from the first constant current source is added to the base when the first switching element is on, based on the current consumption value of the oscillation circuit. A large current flows through the output signal line. In the case of a liquid level abnormality, when the first switching element is on based on the current consumption value of the oscillation circuit and the current value from the second constant current source, the first constant is applied to the base. A current having a magnitude obtained by adding the value of the current from the current source flows to the output signal line. Therefore, it is possible to detect whether the liquid level is normal or abnormal from the magnitude of the current flowing through the output signal line. In the configuration in which the liquid level detection electrode is directly connected to the second constant current source without providing the second switching element and the third switching element, the wall surface above the liquid level of the storage battery due to vibration of the storage battery or the like. Due to the leakage current caused by the electrolytic solution adhering to the liquid, the current continues to flow even if the liquid level detection electrode is slightly separated from the liquid level, and the detection accuracy of the liquid level may be deteriorated. However, by providing the second and third switching elements, it is possible to prevent deterioration in detection accuracy due to the leakage current. Furthermore, even when the liquid level is abnormal, it is possible to output liquid temperature information to the output signal line, and even when the liquid temperature is abnormal, it is possible to output liquid level information to the output signal line. Become.

  According to a sixth aspect of the present invention, in the first aspect of the present invention, the liquid level detection electrode is connected to the positive side of the constant current source and the power source of the oscillation circuit. ing. In the present invention, when the liquid surface state is normal, the liquid temperature state is detected as in the case of the invention according to any one of claims 1 to 3. On the other hand, when the liquid level is abnormal, that is, when the liquid level detection electrode is detached from the electrolyte, the current flowing through the output signal line becomes zero.

  The invention according to claim 7 is the invention according to any one of claims 2 to 6, wherein the temperature detecting resistor is connected in parallel with another external resistor constituting the time constant setting circuit. Has been. In the present invention, in a state where the temperature detection resistor is disconnected, the combined resistance value of the external resistors of the time constant setting circuit increases, and the output pulse period of the oscillation circuit set by the time constant setting circuit increases. Therefore, it is possible to distinguish between the disconnection abnormality of the temperature detection resistor and the disconnection abnormality of another part of the oscillation circuit. Further, it is possible to detect the presence or absence of an abnormality in the liquid level even in a state where the temperature detection resistor is disconnected.

  According to the present invention, a storage battery state detection device capable of outputting liquid temperature and liquid level information with a single output signal line and preventing erroneous detection even if a potential difference occurs in the negative line of the storage battery. Can be provided.

The circuit diagram of a 1st embodiment. (A) is a time chart of signal line current indicating the liquid surface state, (b) is a time chart of signal line current indicating the liquid temperature state, and (c) is a time chart of signal line current indicating disconnection of the temperature sensor. The circuit diagram of a 2nd embodiment. The circuit diagram of a 3rd embodiment. The schematic diagram of the storage battery state detection apparatus of a prior art.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is embodied in a storage battery state detection device equipped in a storage battery mounted on a vehicle will be described with reference to FIGS. 1 and 2.

As shown in FIG. 1, the storage battery state detection device 10 includes a liquid level detection electrode 11, a temperature detection resistor 12, and one output signal line 13.
The liquid level detection electrode 11 is connected to the output signal line 13 via a first switching element 16 that is turned on / off by the output of the first constant current source 14 and the oscillation circuit 15. More specifically, the liquid level detection electrode 11 is connected to the first constant current source 14 via the diode D1, the resistor R1, and the resistor R2. The diode D1 has a cathode connected to the resistor R1 and an anode connected to the liquid level detection electrode 11. The power supply 17 and the first constant current source 14 of the oscillation circuit 15 are electrically connected to the storage battery 18 via the wiring 19 at a potential lower than the potential of the liquid level detection electrode 11. In the wiring 19, a diode D <b> 2 is provided with a cathode connected to a connection point between the resistor R <b> 2 and the first constant current source 14 and an anode connected to the storage battery 18. An NPN bipolar transistor is used for the first switching element 16, the collector is connected to the first constant current source 14, the emitter is connected to the output signal line 13, and the base is connected to the oscillation circuit 15 via the resistor R 3. The output terminal is connected to the output signal line 13 via a resistor R4.

  Further, the second switching element 20 is connected between the liquid level detection electrode 11 and the wiring 19, and the wiring 19 and the output signal line 13 are turned on when the second switching element 20 is turned on. The switching element 21 and the second constant current source 22 are electrically connected. More specifically, a PNP bipolar transistor is used for the second switching element 20, and an NPN bipolar transistor is used for the third switching element 21. The second switching element 20 has an emitter connected to the connection point of the resistors R1 and R2, a collector connected to the base of the third switching device 21 via the resistor R5, and a base connected to the collector of the third switching device 21. ing. The third switching element 21 has a collector connected to the second constant current source 22 and a base connected to the second constant current source 22 via a resistor R6. The second switching element 20 and the third switching element 21 are turned on when a current flows through the liquid level detection electrode 11. In other words, the current from the second constant current source 22 is supplied to the output signal line 13 when the liquid level detection electrode 11 is in a normal state.

  The oscillation circuit 15 includes external resistors R7 and R8 and a capacitor C connected to the timer IC 23 in order to set on / off timing of the timer IC 23 and a capacitive discharge switch (not shown) built in the timer IC 23. And a time constant setting circuit 24 having the same. The temperature detection resistor 12 is connected in parallel to the external resistor R8. That is, the temperature detection resistor 12 constitutes a part of the time constant setting circuit 24. The power supply 17, the timer IC 23, and the ground side of the capacitor C are connected to the output signal line 13. That is, at least one of the current flowing through the oscillation circuit 15 and the current flowing through the power source 17 is supplied to the output signal line 13. More specifically, for example, a known timer IC 555 is used as the timer IC 23, the connection point between the external resistor R7 and the external resistor R8 is connected to the discharge terminal, and the connection point between the external resistor R8 and the capacitor C. Are connected to both the trigger terminal and the threshold (threshold) terminal to form an astable multivibrator. The output terminal of the timer IC 23 becomes the output terminal of the oscillation circuit 15.

  A current detection device 30 is provided on the vehicle side. The output signal line 13 is connected to one end of a current detection resistor R10 provided on the vehicle side via a diode D3, and the other end of the current detection resistor R10 is connected to the negative terminal of the storage battery 18. The current detection device 30 detects the current value output from the output signal line 13 by detecting the voltage of the current detection resistor R10. The detection signal of the current detection device 30 is sent to the control device 31. The control device 31 includes a microcomputer, and determines from the detection signal of the current detection device 30 whether there is an abnormality in the liquid surface state and the liquid temperature state of the storage battery 18.

  If the controller 31 determines that the liquid level is abnormal or the liquid temperature is abnormal, the controller 31 performs necessary processing. Necessary processes include, for example, a process of outputting a drive signal to an abnormal display device such as an abnormal indicator lamp or a buzzer (not shown) and a performance limit process of the vehicle. Examples of the vehicle performance limiting process include travel vehicle speed limitation and acceleration limitation.

Next, the operation of the apparatus configured as described above will be described.
A current is supplied to the power source 17 and the first constant current source 14 via the wiring 19 regardless of whether there is an abnormality in the liquid level and the liquid temperature of the storage battery 18. In addition, when the liquid level of the storage battery 18 is normal, current is supplied to the power source 17 and the first constant current source 14 via the liquid level detection electrode 11.

  In a state where current is supplied through the liquid level detection electrode 11, the second switching element 20 is held in the on state, and the third switching element 21 is also held in the on state. Then, the current I2 from the second constant current source 22 flows through the output signal line 13. Further, the current I1 from the first constant current source 14 flows to the output signal line 13 while the first switching element 16 is in the ON state. Further, in a state where the power source 17 can supply power, the output signal line 13 has a power source regardless of whether the first switching element 16, the second switching element 20, and the third switching element 21 are on or off. 17 and the current I0 used in the oscillation circuit 15 flows. As a result, a change with time as shown in FIG. 2A occurs as a change with time of the current that can be used for detection of the liquid surface state.

  That is, when the liquid level is normal, as shown on the left side of FIG. 2A, a rectangular wave signal is output in which the L level current value is (I0 + I2) and the H level current value is (I0 + I1 + I2). It is repeatedly output from the signal line 13. When the liquid level is abnormal, as shown on the right side of FIG. 2A, a rectangular wave signal with an L level current value of I0 and an H level current value of (I0 + I1) is output signal line. 13 is repeatedly output.

  On the other hand, when the current is supplied from the power source 17 to the oscillation circuit 15, the timer IC 23 is at the L level at a time interval determined by the resistance values of the external resistors R7 and R8 and the temperature detection resistor 12 and the capacitance of the capacitor C. A pulse signal that repeats the above state and the H level state is output from the output terminal, and this signal becomes the output of the oscillation circuit 15. The first switching element 16 is turned on while the output of the timer IC 23 is at the H level, and the first switching element 16 is turned off while the output of the timer IC 23 is at the L level. When the combined resistance of the external resistor R8 and the temperature detecting resistor 12 is Rh, the H level time TH and the L level time TL are expressed by the following equations. However, k is a constant.

TH = k · (R7 + Rh) · C
TL = k ・ Rh ・ C
Rh = R12 · R8 / (R12 + R8)
That is, as the resistance value of the temperature detection resistor 12 increases, the resistance value of the combined resistor Rh increases and the time TH and time TL increase. Therefore, for example, when the temperature detecting resistor 12 whose resistance value increases at a high temperature is used, the time TH increases when the liquid temperature of the storage battery 18 becomes high, and the time TH when the liquid temperature of the storage battery 18 becomes low. Becomes shorter. On the other hand, when the temperature detecting resistor 12 whose resistance value increases when the temperature becomes low, the time TH becomes long when the liquid temperature of the storage battery 18 becomes low. As a result, the current I1 flowing in the output signal line 13 in a pulse state as a signal for detecting the liquid temperature state is abnormal when the liquid temperature is normal as shown in FIG. When the liquid temperature is abnormal, the pulse width becomes long.

  As described above, the current I0 and the current I2 flow in the normal state of the liquid level, and the current I0 flows in the abnormal state of the liquid level regardless of whether the first switching element 16 is turned on or off. . Therefore, the L-level current value in FIG. 2B is (I0 + I2) in the normal liquid level state and I0 in the abnormal liquid level state. Further, the H level current value in FIG. 2B is (I0 + I1 + I2) in the normal liquid level state and (I0 + I1) in the abnormal liquid level state.

  When the temperature detection resistor 12 is disconnected, the time TH when the output of the timer IC 23 is at the H level is k · (R7 + R8), which is much longer than when the temperature detection resistor 12 is not disconnected. . When the output signal line 13 is disconnected, the current flowing through the output signal line 13 becomes zero. Therefore, a change with time as shown in FIG. 2C occurs as a change with time of current that can be used for detection of disconnection of the temperature detection resistor 12 and disconnection of the output signal line 13.

  As described above, information on whether or not the liquid temperature of the storage battery 18 is normal is output from the output signal line 13 as a pulse current having a different pulse width, and information on whether or not the liquid level is normal is a pulse current having a different current value. Output from the output signal line 13.

  The output signal of the output signal line 13 flows to the current detection resistor R10, and the signal line current is detected by the current detection device 30. Based on the detection signal of the current detection device 30, the control device 31 provided on the vehicle side determines whether there is an abnormality in the liquid surface state and the liquid temperature state, whether the temperature detection resistor 12 is disconnected, It is determined whether or not the output signal line 13 is disconnected. Specifically, when the rectangular wave with the L level being (I0 + I2) and the H level being (I0 + I1 + I2) is repeated at times TH and TL when the liquid temperature is normal, it is determined that both the liquid temperature and the liquid level are normal. When a rectangular wave having an L level of I0 and an H level of (I0 + I1) is repeated at times TH and TL when the liquid temperature is normal, it is determined that the liquid temperature is normal and the liquid level is abnormal. In addition, when a rectangular wave having an L level of (I0 + I2) and an H level of (I0 + I1 + I2) is repeated at times TH and TL when the liquid temperature is abnormal, it is determined that the liquid temperature is abnormal and the liquid level is normal. If a rectangular wave having an L level of I0 and an H level of (I0 + I1) is repeated at times TH and TL when the liquid temperature is abnormal, it is determined that the liquid temperature and the liquid level are abnormal. If the duration of the H level reaches the time at which the temperature detection resistor 12 is disconnected regardless of the values of the L level and the H level, it is determined that the temperature detection resistor 12 is disconnected and the detected current value becomes zero. It is determined that the output signal line 13 is disconnected.

  Since a load such as a motor is connected to the storage battery 18 mounted on the vehicle, a potential difference may occur in the negative line of the storage battery 18. Therefore, as in the storage battery state detection device of Patent Document 1, when the liquid temperature and liquid level information is sent from the output signal line 13 as voltage information, the output voltage from the output signal line 13 fluctuates due to potential fluctuations. There is a risk of erroneous detection in the voltage detection device. However, in this embodiment, since the information on the liquid temperature state and the liquid surface state is output as current information instead of voltage information, erroneous detection is prevented even if a potential difference occurs in the negative line of the storage battery 18.

According to this embodiment, the following effects can be obtained.
(1) The storage battery state detection device 10 includes a liquid level detection electrode 11, a temperature detection resistor 12, and one output signal line 13. The output signal line 13 includes a current flowing through the liquid level detection electrode 11. The current flowing from the constant current source (first constant current source 14) is supplied through the switching element (first switching element 16) that is on / off controlled by the output of the oscillation circuit 15. The oscillation circuit 15 is composed of an astable multivibrator, and the temperature detection resistor 12 is used in a circuit for setting the oscillation cycle. The power supply 17 and the first constant current source 14 of the oscillation circuit 15 are in a storage battery state. Power is supplied from the storage battery 18 to which the detection device is mounted. Therefore, liquid temperature and liquid level information can be output by a single output signal line, and erroneous detection can be prevented even if a potential difference occurs in the negative line of the storage battery.

  (2) The oscillation circuit 15 includes a timer IC 23 and a time constant setting circuit 24 including external resistors R7 and R8 and a capacitor C connected to the timer IC 23 in order to set the on / off timing of the timer IC 23. In addition, the temperature detection resistor 12 constitutes a part of the time constant setting circuit 24. The power source 17 and the first constant current source 14 are electrically connected to the storage battery 18 via the wiring 19 at a location where the potential is lower than the potential of the liquid level detection electrode 11. The detection electrode 11 is used in a state where it contacts the electrolyte of the storage battery 18. Therefore, it is possible to detect whether or not the liquid temperature is an abnormal temperature based on a cycle in which the current flowing through the output signal line 13 flows at a certain value or more. In addition, even when the temperature detection resistor 12 is disconnected, it is possible to detect whether or not the liquid level is abnormal. That is, the liquid temperature information can be output to the output signal line 13 even when the liquid level is abnormal, and the liquid level information can be output to the output signal line 13 even when the liquid temperature is abnormal. It becomes possible.

  (3) The second switching element 20 is connected between the liquid level detection electrode 11 and the wiring 19. The wiring 19 and the output signal line 13 are electrically connected via a third switching element 21 and a second constant current source 22 that are turned on when the second switching element 20 is turned on. The current I2 flows from the second constant current source 22 to the output signal line 13 while the switching element 20 and the third switching element 21 are on. Then, whether the liquid level is normal or abnormal can be detected from the magnitude of the current flowing through the output signal line 13. If the liquid level detection electrode 11 is only slightly away from the liquid level of the storage battery 18, a slight leak current is detected due to the electrolyte adhering to the wall surface above the liquid level of the storage battery 18 due to vibration of the storage battery 18 or the like. It may flow through the electrode 11. Therefore, in the configuration in which the liquid level detection electrode 11 is connected to the second constant current source 22 without providing the second switching element 20 and the third switching element 21, the liquid level detection electrode 11 is slightly from the liquid level. Even if they are separated from each other, the current I2 flows from the second constant current source 22 to the output signal line 13 due to the slight leak current, and there is a possibility that the detection accuracy of the liquid surface state is deteriorated. However, when the second and third switching elements 20 and 21 are provided, if the second and third switching elements 20 and 21 are not turned on by the leakage current, the output from the second constant current source 22 is performed. The current I2 does not flow to the signal line 13. Accordingly, the resistance values of the resistors R1, R2, R5, and R6 are set so that the second and third switching elements 20 and 21 are not turned on depending on the leakage current, thereby preventing deterioration of the liquid level state detection accuracy. can do.

  (4) The temperature detection resistor 12 is connected in parallel with another external resistor R8 that constitutes the time constant setting circuit 24. When the temperature detection resistor 12 is connected in series with another external resistor constituting the time constant setting circuit 24, the capacitor C cannot be charged / discharged when the temperature detection resistor 12 is disconnected. However, in this embodiment, when the temperature detection resistor 12 is disconnected, the combined resistance value of the external resistors of the time constant setting circuit 24 increases, and the output pulse period of the oscillation circuit 15 set by the time constant setting circuit 24 is become longer. Therefore, it is possible to distinguish between the disconnection abnormality of the temperature detection resistor 12 and the disconnection abnormality of other portions of the oscillation circuit 15.

  (5) A state in which the current I1 from the first constant current source 14 and the current I2 from the second constant current source 22 do not flow through the output signal line 13, that is, the liquid level detection electrode 11 is detached from the electrolyte, Even when the temperature detection resistor 12 is disconnected, the current flowing through the oscillation circuit 15 and the current I0 flowing through the power source 17 are supplied. Therefore, the presence or absence of disconnection of the output signal line 13 can be detected based on whether or not a current equal to or greater than the current I0 is flowing.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. In this embodiment, the second switching element 20 and the third switching element 21 are not provided, and the current from the liquid level detection electrode 11 is directly supplied from the diode D1 to the second constant current source 22. This is different from the first embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, the liquid level detection electrode 11 is directly connected to the second constant current source 22 via the diode D1. Further, since the second switching element 20 and the third switching element 21 are not provided, the second switching element 20 and the third switching element 21 are turned on at a predetermined timing, that is, the second switching element 20 is turned on. Also, resistors R1, R2, R5, and R6 for turning on the third switching element 21 in the state are not provided.

  In this embodiment, as in the first embodiment, in a state where the liquid level is normal, that is, in a state where the liquid level detection electrode 11 is not detached from the electrolyte of the storage battery 18, a current is supplied from the second constant current source 22. I2 flows through the output signal line 13. When the liquid level is abnormal, that is, when the liquid level detection electrode 11 is detached from the electrolytic solution of the storage battery 18, the current I2 does not flow from the second constant current source 22 to the output signal line 13. On the other hand, the action of the oscillation circuit 15, that is, the action of detecting the presence or absence of an abnormality in the liquid temperature is the same as that of the first embodiment. Therefore, the current output from the output signal line 13 is output in a state that changes in the same manner as in FIGS. 2A to 2C of the first embodiment, corresponding to the liquid temperature and the state of the liquid level. .

Therefore, according to the second embodiment, in addition to the same effects as (1), (4), and (5) of the first embodiment, the following effects can be obtained.
(6) Since the second and third switching elements 20 and 21 are not provided and the resistors R1, R2, R5, and R6 are unnecessary, the configuration is simplified and the manufacturing cost can be reduced.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG. In this embodiment, the path through which the current is supplied from the storage battery 18 to the storage battery state detection device 10 is one path through the liquid level detection electrode 11, and there is no second constant current source 22 but a constant current source. The point that only the first constant current source 14 is provided is largely different from both the above embodiments. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, the liquid level detection electrode 11 is connected to the positive side of the first constant current source 14 and the power source 17 via the diode D <b> 2 and the wiring 19. The second and third switching elements 20 and 21, the second constant current source 22, the diode D1, and the resistors R1, R2, R5, and R6 are not provided.

  In this embodiment, when the liquid level is normal, that is, when the liquid level detection electrode 11 is not detached from the electrolytic solution of the storage battery 18, the liquid level detection electrode 11 is connected to the first constant current source 14 and the power source 17. Current is supplied. A current I 0 flows through the output signal line 13 regardless of whether the first switching element 16 is on or off. Further, the current I1 from the first constant current source 14 flows to the output signal line 13 while the first switching element 16 is in the ON state. On the other hand, when the liquid level is abnormal, that is, when the liquid level detection electrode 11 is detached from the electrolytic solution of the storage battery 18, no current is supplied to the first constant current source 14 and the power source 17, and the oscillation circuit 15. Is not activated.

  Therefore, unlike the two embodiments, the liquid temperature state cannot be detected in the abnormal liquid level state. In addition, since the second constant current source 22 does not exist, the change shown in FIG. 2A is eliminated as the change in the signal current flowing through the output signal line 13 as the first switching element 16 is turned on / off. The liquid level abnormality is not detected based on the change in the signal current shown in FIG. 2A, but is performed based on whether or not the signal current flowing through the output signal line 13 becomes zero. Sometimes the liquid level becomes abnormal.

Therefore, according to the second embodiment, in addition to the same effects as (1) and (4) of the first embodiment, the following effects can be obtained.
(7) Since the second and third switching elements 20 and 21, the second constant current source 22, the diode D1 and the resistors R1, R2, R5, and R6 are not provided, the configuration is simplified and the manufacturing cost is further increased. Can be reduced.

The embodiment is not limited to the above, and may be embodied as follows, for example.
The astable multivibrator constituting the oscillation circuit 15 is composed of a timer IC 23 and a time constant setting circuit 24 comprising external resistors R7 and R8 connected to the timer IC 23, a temperature detection resistor 12 and a capacitor C. Not limited to. For example, the temperature detection resistor 12 may be used as one of the resistors of a general astable multivibrator including four resistors, two capacitors, and two transistors.

  The temperature detecting resistor 12 constituting the time constant setting circuit 24 may be connected in parallel with the external resistor R7 instead of being connected in parallel with the external resistor R8. When the temperature detection resistor 12 is connected in parallel with the external resistor R7, the time TH when the output of the timer IC 23 is at the H level changes with the temperature change of the temperature detection resistor 12, but the time TL when the output at the L level changes. do not do.

  The temperature detection resistor 12 constituting the time constant setting circuit 24 may be connected in series with another external resistor. For example, the temperature detection resistor 12 may be connected instead of the external resistor R7, or the temperature detection resistor 12 may be connected instead of R8. However, in this case, if the temperature detection resistor 12 is disconnected, the capacitor C cannot be charged or discharged.

  The output signal line 13 only needs to be supplied with at least one of the current flowing through the oscillation circuit 15 and the current flowing through the power supply 17, and the current flowing through the oscillation circuit 15 and the power supply 17 flows through the output signal line 13. Not limited to. For example, a ground for the oscillation circuit 15 or the power supply 17 may be provided separately, and either the current flowing through the oscillation circuit 15 or the current flowing through the power supply 17 may flow through the output signal line 13.

  The first switching element 16, the second switching element 20, and the third switching element 21 are not limited to bipolar transistors, and for example, MOS transistors may be used.

The storage battery state detection device 10 is not limited to the storage battery 18 mounted on the vehicle, and may be used for a storage battery that is used in a state of being fixed at a predetermined position.
○ When the storage battery state detection device 10 is used for a storage battery 18 mounted on a vehicle, a control device 31 is not provided, and an abnormality display device such as an abnormality indicator lamp or a buzzer is driven by a detection signal of the current detection device 30. It is good.

  When the storage battery state detection device 10 is used for the storage battery 18 mounted on the vehicle, the control device 31 first drives an abnormality display device such as an abnormality indicator lamp or a buzzer when the liquid level abnormality or the liquid temperature abnormality occurs. Thereafter, if the liquid temperature abnormality or the liquid level abnormality continues even after a predetermined time has elapsed, the vehicle performance limiting process may be performed.

The following technical idea (invention) can be understood from the embodiment.
(1) A storage battery state detection device including a liquid level detection electrode, a temperature detection resistor, and a single output signal line, wherein information indicating whether the storage battery liquid temperature is normal is a pulse having a different pulse width. A storage battery state detection device that outputs from the output signal line as current, and outputs information on whether or not the liquid level is normal from the output signal line as pulse current having different current values.

  (2) A storage battery equipped with the storage battery state detection device according to any one of claims 1 to 7 and technical idea (1) is mounted, and an output signal of the output signal line is input, A vehicle including a control device that determines whether there is an abnormality in a liquid level state and a liquid temperature state of a storage battery based on a signal.

  C: capacitor, I0, I1, I2 ... current, R1, R2, R3, R4, R5, R6 ... resistor, R7, R8 ... external resistor, 10 ... storage battery state detection device, 11 ... liquid level detection electrode, 12 ... Resistance for temperature detection, 13 ... output signal line, 14 ... first constant current source, 15 ... oscillation circuit, 16 ... first switching element, 17 ... power source, 18 ... storage battery, 19 ... wiring, 20 ... second Switching element 21... Third switching element 22... Second constant current source 23 .. timer IC 24.

Claims (7)

A storage battery state detection device comprising a liquid level detection electrode, a temperature detection resistor, and one output signal line,
The output signal line is supplied with a current that flows through the liquid level detection electrode and a current that flows from a constant current source via a switching element that is on / off controlled by an output of the oscillation circuit.
The oscillation circuit is composed of an astable multivibrator, and the temperature detection resistor is used in a circuit for setting the oscillation cycle.
The power source of the oscillation circuit and the constant current source are supplied with power from a storage battery to which the storage battery state detection device is attached. The astable multivibrator includes a timer IC and a time constant setting circuit including an external resistor and a capacitor connected to the timer IC to set the on / off timing of the timer IC. The temperature detection resistor constitutes a part of the time constant setting circuit,
The storage battery state detection device according to claim 1, wherein a time during which a current from the constant current source is supplied to the output signal line varies depending on a value of the temperature detection resistor.   The storage battery state detection device according to claim 1 or 2, wherein at least one of a current flowing through the oscillation circuit and a current flowing through the power source is supplied to the output signal line. The constant current source is a first constant current source, and further includes a second constant current source,
The storage battery state detection device according to any one of claims 1 to 3, wherein the liquid level detection electrode is connected to the output signal line via the second constant current source. The power source and the first constant current source are electrically connected to the storage battery via a wiring at a potential lower than the potential of the liquid level detection electrode,
The switching element is a first switching element, a second switching element is connected between the liquid level detection electrode and the wiring, and the second switching element is on between the wiring and the output signal line. A third switching element that is turned on in a state and the second constant current source, and the second switching element and the third switching element are electrically connected to the liquid level detection electrode. The storage battery state detection device according to claim 4 which is turned on in a flowing state.   The storage battery state detection device according to any one of claims 1 to 3, wherein the liquid level detection electrode is connected to a positive side of a power source of the constant current source and the oscillation circuit.   The storage battery state detection device according to any one of claims 2 to 6, wherein the temperature detection resistor is connected in parallel to another external resistor constituting the time constant setting circuit.

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