JP2008027670A - Lead storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid type lead storage battery capable of detecting that deformation of a cathode plate 3 has exceeded a given deformation volume, with the use of a liquid face detection device 12 detecting fall of a liquid face of electrolyte solution below a given height. <P>SOLUTION: The battery is provided with cathode and anode plates 3, 4, cathode and anode terminals 9, 10, and a liquid face detection device 12 equipped with a liquid face detection electrode 12a. It is also provided with a liquid level judgment means judging that a liquid level of the electrolyte solution 6 gets below a given height in case a relation of a potential difference between the cathode and the anode terminals 9, 10 and that between the liquid face detection electrode 12a and the anode terminal 10 satisfies a predetermined first condition, as well as a cathode plate deformation judging means judging that the deformation of the cathode plate 3 exceeds a given deformation volume in case a relation of a potential difference between the cathode and the anode terminals 9, 10 and that between the liquid face detection electrode 12a and the anode terminal 10 satisfies a predetermined second condition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid lead-acid battery that can detect a decrease in the liquid level of an electrolyte and detect deformation of a positive electrode plate.

  Since liquid type (open type) lead-acid batteries need to be inspected during maintenance to check whether the electrolyte level injected into each cell chamber of the battery case has fallen below a predetermined height, The liquid level of the electrolyte was confirmed through the outer wall of the light-transmitting battery case, or was confirmed by a float type optical indicator attached to the liquid injection stopper. However, in the case of a lead-acid battery mounted on a vehicle, the lead-acid battery must be confirmed by opening a bonnet or the like. In addition, when the outer wall of the lead-acid battery battery case is black or other light-impervious material that hardly transmits light, it is difficult to pass through the outer wall of the battery case or to check with an optical indicator. There was a case. Furthermore, in the case of a lead storage battery having a liquid reflux chamber in which water evaporated from the electrolyte is condensed (condensed) and refluxed into the original cell chamber, There is almost no decrease, and the liquid level of the electrolyte does not drop below a predetermined height unless it deviates from the assumed use situation. In addition, it is a structure that cannot be refilled from the injection port. Because of various backgrounds such as the above, there is an increased risk of overlooking the rare reduction of the electrolyte that occurs rarely.

  Therefore, conventionally, a liquid level detection device in which the liquid level detection electrode is immersed in the electrolytic solution is arranged in the cell chamber, and the liquid level of the electrolytic solution is determined by examining the potential of the liquid level detection electrode as needed. There has been a lead storage battery in which an alarm device such as a buzzer or a lamp is operated when the liquid level detection electrode is not soaked in the electrolyte due to a drop from the height (for example, see Patent Documents 1 to 3).

In addition, the positive electrode plate of a lead-acid battery repeats expansion and contraction of lead dioxide, which is an active material, as charge and discharge are repeated. With the use of the period, the upper end of the lattice body excluding the ear portion 3a in the positive electrode plate 3 is expanded and deformed upward as shown by a one-dot chain line B in FIG. There is a risk of internal short circuit. Therefore, conventionally, there has been a lead storage battery in which an expansion device deformation is electrically detected by a sensor to activate an alarm device such as a light emitting diode (see, for example, Patent Documents 4 to 6).
Japanese Utility Model Publication No. 5-15322 JP-A-5-82174 JP-A-5-74502 Japanese Patent Application Laid-Open No. 8-115575 JP-A-8-227733 JP-A-8-273704

  The present invention provides a lead-acid battery capable of detecting that the deformation of a positive electrode plate exceeds a predetermined deformation amount by using a liquid level detection device that detects that the liquid level of the electrolytic solution has fallen below a predetermined height. It is something to try.

  The liquid lead-acid battery according to claim 1 includes a positive and negative electrode plate, a positive and negative electrode terminal, and a liquid level detection device having a liquid level detection electrode, and a potential difference between the positive and negative electrode terminals and the liquid level detection electrode and the negative electrode terminal. A liquid level determination means for determining that the liquid level of the electrolytic solution has fallen below a predetermined height when the relationship with the potential difference between the two satisfies the first predetermined condition; And a positive electrode plate deformation determining means for determining that the deformation of the positive electrode plate exceeds a predetermined deformation amount when the relationship between the potential difference between the electrode and the negative electrode terminal satisfies a predetermined second condition. Features.

  According to the invention of claim 1, when the liquid level of the electrolytic solution of the liquid type lead-acid battery is normal, the liquid level detection electrode is immersed in the electrolytic solution, but the liquid level of the electrolytic solution is lower than a predetermined height. In this case, since the liquid level detection electrode is not immersed in the electrolytic solution, the relationship between the potential difference between the positive and negative electrode terminals and the potential difference between the liquid level detection electrode and the negative electrode terminal is determined by the liquid level determination means. It is possible to determine that the liquid level has fallen below a predetermined height by checking whether or not the above condition is satisfied. In addition, when the deformation of the positive electrode plate exceeds a predetermined deformation amount, the liquid level detection electrode comes into contact with this positive electrode plate, so that the positive electrode plate deformation determination means determines the potential difference between the positive and negative terminals and the liquid level detection electrode. By examining whether the relationship with the potential difference with the negative electrode terminal satisfies the second condition, it can be determined that the deformation of the positive electrode plate exceeds a predetermined deformation amount. In addition, since the potential difference between the liquid level detection electrode and the negative electrode terminal changes at a rate corresponding to the potential difference between the positive and negative electrode terminals, the first condition and the first condition are determined based on the relationship with the potential difference between the positive and negative electrode terminals. By determining whether or not the condition 2 is satisfied, it is possible to reliably detect that the liquid level of these electrolytes has decreased below a predetermined height and that the deformation of the positive electrode plate has exceeded a predetermined deformation amount. Become. If this liquid level detection electrode is used, it is possible to detect the deformation of the positive electrode plate in addition to the detection of the liquid level of the electrolytic solution, thereby reducing costs.

  The present invention provides a liquid lead-acid battery in which, for example, electrode plates stored in a cell chamber in a battery case are connected in series, and both ends of these electrode plates connected in series are connected to positive and negative terminals. Or a liquid level detection device having a liquid level detection electrode exposed at least at the lower end in one or more cell chambers, the lower end being immersed in the electrolyte and protruding downward to a position above the positive electrode plate of the electrode group. When the difference or ratio between the potential difference between the positive and negative electrode terminals and the potential difference between the liquid level detection electrode and the negative electrode terminal of the liquid level detection device satisfies a predetermined liquid level determination condition, When the liquid level determination means that determines that the liquid level has dropped below a predetermined height and the difference or ratio of this potential difference satisfies a predetermined positive electrode plate deformation condition, it is determined that the deformation of the positive electrode plate has exceeded a predetermined deformation amount. And a positive electrode plate deformation determination means.

  According to this configuration, when the liquid level of the electrolytic solution in the cell chamber is equal to or higher than a predetermined level, the liquid level detecting electrode of the liquid level detecting device is immersed in the electrolytic solution. Although the potential is the same as that of the negative electrode plate, the liquid level detection electrode of the liquid level detection device is not immersed in this electrolytic solution when the liquid level of the electrolytic solution falls below a predetermined height. Extremely low potential. In addition, when the positive electrode plate of the electrode plate group of the cell chamber is not expanded and deformed, the liquid level detection electrode of the liquid level detection device above the positive electrode plate does not contact the positive electrode plate, When the deformation of the positive electrode plate exceeds a predetermined deformation amount, the liquid level detecting electrode exposed at the lower end of the liquid level detecting device comes into contact with the expanded positive electrode plate and has the same potential as this positive electrode plate. Therefore, the potential difference between the liquid level detection electrode of the liquid level detection device and the negative electrode terminal is lowest when the liquid level of the electrolytic solution falls below a predetermined height, and the position of the liquid level of the electrolytic solution is normal and the positive electrode When the size of the plate is normal, it is sufficiently higher than this, and when the deformation of the positive electrode plate exceeds a predetermined deformation amount, it is further increased by the electromotive force of the electrode plate group of one cell. In addition, since the potential difference between the liquid level detection electrode and the negative electrode terminal of this liquid level detection device changes at a rate corresponding to the potential difference between the positive and negative electrode terminals, the difference or rate between the potential difference between the positive and negative electrode terminals is By determining whether the liquid level judgment condition and the positive electrode plate deformation condition are satisfied, it is reliably detected that the liquid level of these electrolytes has fallen below a predetermined height and that the deformation of the positive electrode plate has exceeded a predetermined deformation amount. Will be able to.

  Here, the position above the positive electrode plate means a position above the upper end of the lattice body excluding the ears protruding from the positive electrode plate for connection to the positive electrode strap, and the greatest upward deformation occurs. Above the site is preferred. In addition, in order to reliably prevent a short circuit between the positive electrode plate and the negative electrode strap, when the lower end of the liquid level detection electrode of the liquid level detection device is disposed above the portion of the positive electrode plate close to the negative electrode strap, this negative electrode strap It is preferable to place it at a position slightly lower than the lower end surface of the negative electrode, but when it is arranged above the portion of the positive electrode plate where the upward deformation is greatest, it is at a position above the lower end surface of the negative electrode strap. Sometimes it is better to place it. And by arranging the lower end of the liquid level detection electrode of the liquid level detection device in this way, it becomes possible to detect that the deformation of the positive electrode plate exceeds a predetermined deformation amount, and the liquid level of the electrolyte solution It is also possible to detect that has fallen below a predetermined height.

  The first condition or the second condition of claim 1 is that the difference or ratio between the potential difference between the positive and negative terminals and the potential difference between the liquid level detection electrode and the negative terminal of the liquid level detection device is within a predetermined range. In addition to the above-described liquid level determination conditions and positive electrode plate deformation conditions that determine whether or not they are within, for example, the potential difference between the positive and negative terminals, the liquid level detection electrode and the negative electrode of this liquid level detection device Whether the value obtained by any other relational expression using both the potential difference with the terminal as a parameter is within a predetermined range is used as a condition for determining suitability / improperness, and the potential difference between the positive and negative terminals and the liquid level The potential difference between the liquid level detection electrode and the negative electrode terminal of the detection device is classified into each appropriate voltage range (quantized / discretized), and appropriate / inappropriate for each combination of these potential differences is set in a table. It can also be a condition that makes a determination based on

  Hereinafter, the best embodiment of the present invention will be described with reference to FIGS. In these drawings, the same reference numerals are given to constituent members having the same functions as those of the conventional example shown in FIG.

  This embodiment demonstrates the liquid type lead acid battery for motor vehicles shown in FIG. This lead storage battery includes a resin-made rectangular container-like battery case 1 and a resin-made battery case lid 2 that closes and seals the upper end opening of the battery case 1. As shown in FIG. 2, the inside of the battery case 1 is divided into a plurality of (six in this embodiment) cell chambers 1b by partition walls 1a, and each cell chamber 1b has a plurality of sheets. The electrode plate group in which the positive electrode plate 3 and the negative electrode plate 4 are laminated via the separator 5 is accommodated, and the electrolyte solution 6 is filled. The positive electrode plate 3 and the negative electrode plate 4 of the electrode plate group are connected to a positive electrode strap 7 and a negative electrode strap 8 disposed above the electrode plate group, as shown in FIGS. The positive electrode strap 7 of each cell chamber 1b is connected to the negative electrode strap 8 of the cell chamber 1b adjacent to one through the through hole of the partition wall 1a, and the negative electrode strap 8 of each cell chamber 1b is also adjacent to the other. The positive electrode strap 7 of the cell chamber 1b to be connected to the through hole of the partition wall 1a, whereby the electrode plate groups of all the cell chambers 1b are connected in series.

  Since the battery case 1 uses a resin colored in black or the like in order to improve the appearance of the lead-acid battery, the outer wall and the like are light-impermeable that hardly transmits light. Therefore, it is difficult to examine the position of the electrolyte 6 in the cell chamber 1b through the outer wall of the battery case 1, and since almost no light enters the cell chamber 1b, the optical liquid level detector can It is also difficult to confirm the floating position (for example, color).

  The battery case lid 2 is made of a light-impermeable resin like the battery case 1, and is sealed and fixed to the upper end opening of the battery case 1 by heat welding or the like. At this time, each cell chamber 1b of the battery case 1 is also sealed at the upper end of the partition wall 1a and separated for each cell chamber 1b. Further, the battery case lid 2 is embedded with a positive electrode terminal 9 and a negative electrode terminal 10 which are respectively penetrated and sealed from the cell chambers 1b and 1b at both ends toward the outside. These terminals 9 and 10 become external terminals of the lead storage battery by being connected to the positive strap 7 and the negative strap 8 in the cell chambers 1b and 1b at both ends, respectively.

  As shown in FIGS. 1 and 3, a liquid reflux chamber 2 a is formed in the battery case lid 2. The liquid reflux chamber 2 a is configured by a space formed by a recess formed on the upper surface of the battery case lid 2, and the upper opening is closed by the liquid reflux chamber lid 11. The liquid reflux chamber 2a is divided into six small chambers via liquid reflux chamber partition walls 2b formed at positions corresponding to the partition walls 1a so as to correspond to the six cell chambers 1b of the battery case 1. ing. However, the liquid reflux chamber partition 2b is configured such that adjacent small chambers communicate with each other through a slit or the like (not shown). In each small room divided by the liquid reflux chamber partition wall 2b, an exhaust port 2c and a reflux port 2d communicating with the corresponding cell chamber 1b are formed. When water vapor or mist-like electrolyte leaked from the cell chamber 1b enters the small chamber of the liquid reflux chamber 2a through the exhaust port 2c, it condenses and becomes liquid in the small chamber partitioned by the partition, From the reflux port 2d at the bottom of the inclined surface, it is refluxed again to the original cell chamber 1b. Further, when oxygen gas and hydrogen gas generated by electrolysis in the cell chamber 1b enter the small chamber of the liquid reflux chamber 2a through the exhaust port 2c, the small chambers at both ends are passed through the slits of the liquid reflux chamber partition wall 2b. And is discharged to the outside through a filter 11 a attached to the lower surface of the liquid reflux chamber lid 11.

  The battery case lid 2 is provided with a liquid level detection device mounting hole 2e that opens to the upper surface through the cell chamber 1b adjacent to the cell chamber 1b to which the positive electrode terminal 9 is directly connected. As shown in FIG. 3, the liquid level detection device 12 is mounted in the liquid level detection device mounting hole 2e. The liquid level detection device 12 is a resin component in which a liquid level detection electrode 12a made of pure lead is embedded and the upper part is fixed to the liquid level detection device mounting hole 2e to seal the opening, and the lower part Enters the lower cell chamber 1b and protrudes downward. Further, the lower end of the liquid level detection device 12 is immersed in the electrolytic solution 6 and is a position above any positive electrode plate 3 in the electrode plate group and is slightly lower than the lower end surface of the negative electrode strap 8. It is supposed to be arranged in. The liquid level detection electrode 12a may be a conductive material that is stable with respect to the electrolytic solution 6, and is not necessarily made of pure lead.

  The liquid level detection electrode 12a is arranged from the upper part to the lower part of the liquid level detection device 12 so that it can come into contact with the positive electrode plate 3 when it deforms beyond a predetermined deformation amount. It only needs to be exposed at the bottom. That is, the liquid level detection electrode 12 a is preferably exposed at the lower end of the liquid level detection device 12. For example, FIG. 4 (a) shows what protrudes further downward from the lower end surface of the liquid level detection device 12 as shown in FIG. 2 and FIG. 3, but as shown in FIG. 4 (b), It may only be exposed flush with the lower end surface of the liquid level detection device 12. However, it is not essential that the liquid level detection electrode 12a is exposed at the lower end of the liquid level detection device 12. For example, as shown in FIG. 4C, the lower surface of the liquid level detection device 12 is parallel to the positive electrode plate 3. The liquid level detection device 12 may be arranged so that the liquid level detection electrode 12a is exposed in the opening slot 12b and the deformed positive electrode plate 3 enters the gap of the slot 12b. For example, as shown in FIG. 4 (d), a notch 12c having a semicircular cross section is provided in the lower part of the liquid level detection device 12, and a flat surface facing the side formed by the notch 12c is provided. The liquid level detection device 12 may be arranged such that the liquid level detection electrode 12 a is exposed on the surface, and the exposed surface of the liquid level detection electrode 12 a is adjacent to the positive electrode plate 3.

  If the liquid level detection electrode 12a is made of an elastic structure or material, the effect of stress relaxation accompanying the deformation of the positive electrode plate can be imparted. When the liquid level detection electrode 12a protrudes further downward from the lower end surface of the liquid level detection device 12, the tip of the liquid level detection electrode 12a is formed in a coil shape, or as shown in FIG. If the plate-like liquid level detection electrode 12a is protruded downward and the tip is opened in two, the deformed positive electrode plate 3 enters between and contacts the two plate-like shapes of the liquid level detection electrode 12a. The deformation force of the positive electrode plate 3 can be relaxed. Also, as shown in FIG. 4 (f), when the liquid level detection electrode 12a is folded into a bellows shape and protruded downward, the liquid level detection electrode 12a is deformed by the elasticity of the sheet-like liquid level detection electrode 12a. Not only does the positive electrode plate 3 come into contact, it can also contribute to stress relaxation due to deformation. In addition, if the sheet width of the sheet-like liquid level detection electrode 12a is increased and the width direction is arranged along the stacking direction of the positive electrode plates 3, an opportunity to contact a plurality of deformed positive electrode plates 3 is obtained. Therefore, the detection capability can be increased. The liquid level detection electrode 12a may be a composite of elastic resin such as rubber and conductive powder such as metal powder. As described above, as long as the liquid level detection electrode 12a can be in contact with the deformed positive electrode plate, the shape of the liquid level detection electrode 12a is not particularly limited. Further, the liquid level detection electrode 12a may be any conductor that is stable with respect to the electrolytic solution, and is not necessarily made of pure lead, and is not limited by the embodiment.

  In addition, since the lead acid battery for automobiles normally has the positive electrode terminal 9 disposed on the side close to the engine in the engine room, the cell chamber 1b to which the positive electrode terminal 9 is directly connected becomes the hottest and the electrolyte solution The decrease of 6 is also the largest. For this reason, the liquid level detection device 12 is preferably attached to the cell chamber 1b of the positive electrode terminal 9 or the cell chamber 1b as close as possible to this, and in this embodiment, next to the cell chamber 1b of the positive electrode terminal 9, that is, the positive electrode terminal. Nine cell chambers 1b are attached to the second cell chamber 1b.

  On the upper surface of the battery case lid 2, as shown in FIG. 1, a recessed portion 2f for embedding a liquid level alarm device is formed. The liquid level alarm device 13 is fitted and fixed in the liquid level alarm device embedding recess 2f. As shown in FIG. 5, the liquid level alarm device 13 is operated by being supplied with power from the lead storage battery itself by being connected to the positive and negative terminals 9, 10. It is comprised by the positive electrode plate deformation | transformation determination means 13b, the buzzer 13c, and LED13d. Further, the liquid level determination means 13a and the positive electrode plate deformation determination means 13b are configured to input the potentials of the positive and negative terminals 9, 10 and the liquid level detection electrode 12a of the liquid level detection device 12.

  The liquid level determination means 13a and the positive electrode plate deformation determination means 13b can be configured as an analog circuit using an operational amplifier or the like, or can be configured as a digital circuit via an AD converter. In this embodiment, A microcomputer, a liquid level determination program operating on the microcomputer, and a positive electrode plate deformation determination program are included. Further, the liquid level determination program and the positive electrode plate deformation determination program of the microcomputer are activated at regular intervals to inspect digital data of the potential of the liquid level detection electrode 12a.

  The liquid level determination means 13a and the positive electrode plate deformation determination means 13b issue a warning to the user by sounding the buzzer 13c or turning on the LED 13d according to the detection result. However, the buzzer 13c can change the content of the warning by continuously sounding or intermittently sounding for a certain period of time, and the LED 13d can also select, for example, LEDs whose emission colors are green, yellow, and red, or can be changed to constantly lighting. The content of the warning can be changed by blinking or combining a plurality of light emitting LEDs. In addition, the LED 13d can notify that the electrolyte 6 and the positive electrode plate 3 are normal by lighting only the green LED, for example, at normal times.

  In this embodiment, the detection result of the liquid level determination means 13a and the positive electrode plate deformation determination means 13b appears as digital data at the output port of the microcomputer, so that the driver of the buzzer 13c and the driver of the LED 13d correspond to this digital data. A buzzer sounds and the LED emits light. At this time, the emission color of the LED 13d can be selected depending on the output port. Further, the intermittent sound of the buzzer 13c and the blinking of the LED 13d can be directly controlled by changing digital data appearing at the output port.

  The wiring between the liquid level alarm device 13 and the positive and negative terminals 9, 10 and the liquid level detection electrode 12 a of the liquid level detection device 12 can be performed by, for example, a conductive wire disposed on the upper surface of the battery case lid 2. In this embodiment, wiring is performed by a conductor embedded in the resin of the battery case lid 2 so that it cannot be seen from the outside.

  The operation of the liquid level determination unit 13a and the positive electrode plate deformation determination unit 13b in the liquid level alarm device 13 will be described. The liquid level determination means 13a and the positive electrode plate deformation determination means 13b each input a potential of the liquid level detection electrode 12a of the liquid level detection device 12, thereby detecting a potential difference between the potential of the negative electrode terminal 10 first. At this time, in this embodiment, since the liquid level alarm device 13 is supplied with power from the positive and negative terminals 9 and 10 to set the potential of the negative terminal 10 to the ground potential, the liquid level detection electrode 12a of the liquid level detection device 12 is used. The potential difference between the liquid level detection electrode 12a and the negative electrode terminal 10 can be detected by inputting this potential to the analog port of the microcomputer and converting it to digital data by AD conversion. The liquid level determination means 13a and the positive electrode plate deformation determination means 13b also detect a potential difference between the positive and negative terminals 9 and 10. In this embodiment, the microcomputer or the like is operated using the power supplied from the positive and negative terminals 9 and 10 as a constant voltage power supply by DC-DC conversion, so the potential of the positive terminal 9 is also input to the analog port of this microcomputer. Thus, the potential difference between the positive and negative terminals 9 and 10 can be detected. Then, the liquid level determination unit 13 a and the positive electrode plate deformation determination unit 13 b calculate the ratio (ratio) of the potential difference between the liquid level detection electrode 12 a and the negative electrode terminal 10 with respect to the potential difference between the positive and negative terminals 9 and 10. Note that the calculation of the input of the potential of the liquid level detection electrode 12a and the ratio of the potential difference is common to the liquid level determination means 13a and the positive electrode plate deformation determination means 13b. The liquid level determination means 13a and the positive electrode plate deformation determination means 13b are shared.

Here, when the liquid level of the electrolytic solution 6 in the cell chamber 1b is normal and the positive electrode plate 3 is not excessively deformed, the liquid level detection electrode 12a of the liquid level detection device 12 is immersed in the electrolytic solution 6 and the positive electrode. since the state not in contact with the plate 3, a negative electrode plate 4 at the same potential of the cell chamber 1b by the path shown by the solid line P ₁ in FIG. Therefore, in this embodiment, the electrode plate groups of the six cell chambers 1b are connected in series, and the liquid level detection device 12 is attached from the cell chamber 1b of the positive electrode terminal 9 to the second cell chamber 1b. The ratio of this potential difference is (6-2) / 6 = 2/3. If the potential difference between the positive and negative terminals 9 and 10 is 12.0V, the potential difference of the liquid level detection electrode 12a is 8.0V. And generally, the electrode plate group accommodated in the N cell chambers 1b is connected in series, and the liquid level detection device 12 is provided in the nth cell chamber 1b counted from the cell chamber 1b of the positive electrode terminal 9. In the case of an attached lead storage battery, the ratio of this potential difference is (N−n) / N.

When the liquid level of the electrolytic solution 6 in the cell chamber 1b falls below a predetermined height, the liquid level detection electrode 12a of the liquid level detecting device 12 is not immersed in the electrolytic solution 6, and the solid line P in FIG. Since the path shown in FIG. ₁ disappears, it is opened and becomes substantially the ground potential, that is, the same potential as the negative terminal 10. However, high-viscosity sulfuric acid may remain on the inner wall surface of the cell chamber 1b or the resin surface of the liquid level detection device 12 due to the adhesion of the electrolytic solution 6 and evaporation of only water. The liquid level detection electrode 12a may be connected to the electrolytic solution 6 (the negative electrode plate 4) through a path through the kimono. However, even if such a path due to conductive deposits occurs, the electric resistance is large, and therefore the potential difference between the liquid level detection electrode 12a and the negative electrode terminal 10 is very close to zero.

Furthermore, when the deformation of the positive electrode plate 3 in the cell chamber 1b exceeds a predetermined deformation amount, as shown by a one-dot chain line A in FIG. The upper end of the grid body greatly expands upward and comes into contact with the liquid level detection electrode 12a exposed at the lower end of the liquid level detection device 12 before coming into contact with the negative electrode strap 8, and the broken line P in FIG. _{By the} path shown in FIG. ₂ , the same potential as that of the positive electrode plate 3 in the cell chamber 1b is obtained. Therefore, in the present embodiment, the ratio of the potential difference of the liquid level detection electrode 12a is (6- (2-1)) / 6 = 5/6, and the potential difference between the positive and negative terminals 9 and 10 is 12.0V. The potential difference of the liquid level detection electrode 12a is 10.0V. And generally, the electrode plate group accommodated in the N cell chambers 1b is connected in series, and the liquid level detection device 12 is provided in the nth cell chamber 1b counted from the cell chamber 1b of the positive electrode terminal 9. In the case of an attached lead-acid battery, the ratio of this potential difference is (N− (n−1)) / N, which is higher than the normal case by the electromotive force of the electrode plate group of one cell.

  The liquid level determination means 13a detects a case where the liquid level of the electrolytic solution 6 in the cell chamber 1b is lower than a predetermined height, so that the ratio of the potential difference of the liquid level detection electrode 12a is a predetermined value sufficiently smaller than 2/3. Compared with the liquid level determination ratio, an alarm is issued by the buzzer 13c and the LED 13d when the liquid level determination ratio is less than the ratio. Further, since the positive electrode plate deformation determination means 13b detects that the deformation of the positive electrode plate 3 in the cell chamber 1b exceeds a predetermined deformation amount, the ratio of the potential difference of the liquid level detection electrode 12a is more than 2/3. Compared with a predetermined positive electrode plate deformation determination ratio that is larger than 5/6 and larger than this ratio, an alarm is issued by the buzzer 13c and the LED 13d.

  However, the liquid level of the electrolyte 6 of the lead storage battery rises and falls due to vibrations during traveling of the automobile, and even when the electrolyte 6 is sufficient, the liquid level detection electrode 12a of the liquid level detection device 12 temporarily. In some cases, the electrolytic solution 6 may not be immersed. For this reason, for example, by passing the detected potential difference of the liquid level detection electrode 12a through a low-pass filter and calculating the ratio of the potential difference between the positive and negative terminals 9, 10, the potential difference of the temporary liquid level detection electrode 12a is calculated. It is preferable to carry out detection that is not affected by the decrease in. Also, the potential difference between the positive and negative terminals 9, 10 is often charged at a higher voltage than when the engine is stopped because the lead storage battery is charged when the engine of the automobile is driven. Since the discharge current of the lead storage battery increases during use, the voltage may temporarily decrease. Accordingly, the potential difference between the detected positive and negative terminals 9 and 10 is also affected by temporary fluctuation of the terminal voltage by calculating the ratio with the potential difference of the liquid level detection electrode 12a after passing through the low-pass filter. It is preferable to perform detection that is not performed.

  Furthermore, since the sound of the buzzer 13c is difficult to hear due to the engine sound when the engine is driven, it is better to give a warning by the buzzer 13c after the engine is stopped. Therefore, when the liquid level determination means 13a or the positive electrode plate deformation determination means 13b gives a warning by the buzzer 13c, it is also determined whether or not the engine has stopped, and only when it is determined that the engine has stopped. The buzzer 13c can be sounded. When the engine is stopped, the potential difference between the positive and negative terminals 9 and 10 is lower than that during driving as described above. For example, the detected potential difference between the positive and negative terminals 9 and 10 is passed through a low-pass filter. It can detect by changing to below the predetermined voltage a little higher than the rated voltage of a storage battery.

  In the present embodiment, the low-pass filter (LPF) can be easily realized by an FIR or IIR digital filter configured by a microcomputer program. As a simple digital filter, a program for calculating a moving average can be used.

  In the embodiment described above, the liquid level determination means 13a and the positive electrode plate deformation determination means 13b both indicate the ratio of the potential difference between the liquid level detection electrode 12a and the negative electrode terminal 10 to the potential difference between the positive and negative terminals 9 and 10. Although the case of calculating has been described, either or both may calculate the difference between these potential differences. When the liquid level determination means 13a calculates the difference in potential difference, this difference is about 1/3 (1-2 / 3) of the potential difference between the positive and negative terminals 9 and 10 in the normal state. When the surface drops below a predetermined height, this difference becomes a voltage sufficiently higher than this. Therefore, for example, when 7V is set as the liquid level determination voltage, an alarm is generated by the buzzer 13c or LED 13d when the voltage exceeds this voltage. do it. In addition, when the positive electrode plate deformation determining means 13b calculates the difference in potential difference, this difference is about 1/3 of the potential difference between the positive and negative electrode terminals 9 and 10 in the normal state. When the amount of deformation is exceeded, this difference is about 1/6. Therefore, the difference is sufficiently lower than 1/3 and sufficiently higher than 1/6. When this happens, an alarm may be issued by the buzzer 13c or the LED 13d. Further, the ratio and voltage of these liquid level determination and positive electrode plate deformation determination are reversed depending on which potential difference is the ratio or difference based on which potential difference, and determination conditions corresponding to this are determined.

  Moreover, in the said embodiment, although the case where the battery case 1 and the battery case cover 2 were made of light non-permeable resin was shown, even if these are made of light-transmissive resin, it can implement similarly. For example, if the battery case 1 is made of a light-transmitting resin, the liquid level of the electrolytic solution 6 can be confirmed through the outer wall or with an optical liquid level detection device. It is necessary to perform visual confirmation, and the work becomes troublesome as compared with the case where an alarm is issued by the buzzer 13c or the LED 13d.

  Moreover, although the case where the alarm by the buzzer 13c and LED13d was performed was shown in the said embodiment, the other arbitrary alarm means can be used. Furthermore, in the said embodiment, although the inside of the battery case 1 demonstrated the lead acid battery divided | segmented into six cell chambers 1b, the number of this cell chamber 1b is arbitrary, and when there are several cell chambers 1b, The arrangement is also arbitrary. Furthermore, in the said embodiment, although the lead storage battery provided with the liquid recirculation | reflux chamber 2a was demonstrated, naturally it can implement similarly to the lead storage battery which does not have the liquid recirculation | reflux chamber 2a in which the electrolyte solution 6 tends to reduce. Furthermore, in the said embodiment, although the lead acid battery for motor vehicles was demonstrated, if it is a liquid type lead acid battery, a use is arbitrary. Further, as described above, the shape and arrangement of the liquid level detection device 12 are also arbitrary.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an assembled perspective view showing a configuration of a lead storage battery according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially enlarged longitudinal sectional front view of a cell chamber according to an embodiment of the present invention, to which a liquid level detection device in a lead storage battery is attached. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially enlarged vertical cross-sectional side view of a cell chamber to which an embodiment of the present invention is attached and a liquid level detection device in a lead storage battery is attached. It is a perspective view which shows the example of the exposed structure of the liquid level detection electrode in a liquid level detection apparatus. 1 is a block diagram illustrating a circuit configuration of a liquid level detection device and a liquid level alarm device in a lead storage battery according to an embodiment of the present invention. It is a partial expanded longitudinal cross-section side view of a cell chamber when a deformation | transformation of the positive electrode plate in a lead storage battery shows a prior art example, and exceeds predetermined deformation amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery case 1a Bulkhead 1b Cell chamber 2 Battery case lid 2a Liquid reflux chamber 2b Liquid reflux chamber partition 2c Exhaust port 2d Recirculation port 2e Liquid level detection device mounting hole 2f Liquid level alarm device embedding recess 3 Positive electrode plate 3a Ear 4 Negative electrode plate 5 Separator 6 Electrolyte solution 7 Positive electrode strap 8 Negative electrode strap 9 Positive electrode terminal 10 Negative electrode terminal 11 Liquid return chamber lid 11a Filter 12 Liquid level detection device 12a Liquid level detection electrode 13 Liquid level alarm device 13a Liquid level determination means 13b Positive electrode plate deformation Judgment means 13c Buzzer 13d LED

Claims (1)

  A liquid level detecting device having a positive and negative electrode plate, a positive and negative electrode terminal, and a liquid level detection electrode, wherein a relationship between a potential difference between the positive and negative electrode terminals and a potential difference between the liquid level detection electrode and the negative electrode terminal is predetermined. If the condition of 1 is satisfied, the liquid level determination means for determining that the liquid level of the electrolyte solution has fallen below a predetermined height, and the potential difference between the positive and negative electrode terminals and the potential difference between the liquid level detection electrode and the negative electrode terminal A liquid type lead storage battery comprising: positive electrode plate deformation determining means for determining that the deformation of the positive electrode plate exceeds a predetermined deformation amount when the relationship satisfies a predetermined second condition.

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