JP2006185707A - Lead-acid battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead-acid battery capable of judging the end of the battery life by detecting the abnormal expansion of a positive plate 2 with a pressure sensor 8 installed in a short circuit preventing plate 7 or the like. <P>SOLUTION: In the lead-acid battery in which the insulating short circuit preventing plate 7 is installed between a negative electrode strap 4 connected to a lug part 1a of a negative plate 1 and an insulating part of the positive plate 2 laminated together with the negative plate 1 through a separator 3, the pressure sensor 8 made of pressure-sensitive conductive rubber is bonded on the upper surface of the short circuit preventing plate 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lead storage battery in which a positive electrode plate and a negative electrode plate are accommodated in a battery case such as a battery case via a separator.

  The structural example of the lead acid battery used for an uninterruptible power supply (UPS) is shown. This lead storage battery divides the inside of the battery case into 6 cells by partition walls, and each cell contains an element composed of a negative electrode plate 1, a positive electrode plate 2 and a separator 3 as shown in FIG. The upper end opening of this battery case is closed with a cover plate. FIG. 5 shows only two elements housed in two adjacent cells.

  Each of the above elements is formed by alternately stacking three positive electrode plates 2 via separators 3 between four negative electrode plates 1 arranged in front and rear. The negative electrode plate 1 and the positive electrode plate 2 are made of a lead or lead alloy lattice filled with an active material, and the separator 3 is a porous insulating material made of a nonwoven fabric of glass fiber or the like. The negative electrode plate 1, the positive electrode plate 2, and the separator 3 are each a square plate having a thickness in the front-rear direction. For insulation between the negative electrode plate 1 and the positive electrode plate 2, the separator 3 is formed in a slightly larger square shape. ing. Further, in the lead storage battery used in the uninterruptible power supply device, the positive electrode plate 2 is particularly easily corroded by trickle charging, so that the positive electrode plate 2 is slightly thicker than the negative electrode plate 1.

  Each of the four negative plates 1 has an ear portion 1a projecting upward from the right end portion, and the upper ends of the four ear portions 1a are connected to a common negative electrode strap 4 by welding. The three positive plates 2 also have ears 2a projecting upward from the left end, and the upper ends of the three ears 2a are connected to a common positive strap 5. The negative electrode strap 4 and the positive electrode strap 5 are both casts of lead or lead alloy, and each of the elements collects the four negative plates 1 and the three positive plates 2.

  Each element of the said structure is accommodated in each cell in the battery case 6, as shown to Fig.6 (a). At this time, the separator 3 fits in the left and right and bottom inner surfaces of the battery case 6, but the negative electrode plate 1 and the positive electrode plate 2 have a gap between the left and right inner surfaces of the battery case 6, and the upper end side. Is slightly lower than the upper end side of the separator 3 so as to be reliably insulated. Further, the ear portion 1 a of the negative electrode plate 1 and the ear portion 2 a of the positive electrode plate 2 protrude above the upper end side of the separator 3, and the upper end portion thereof is connected to the negative electrode strap 4 and the positive electrode strap 5. The elements housed in each cell are connected in series via the partition walls by the negative strap 4 and the positive strap 5.

  By the way, as for the positive electrode plate 2 of a lead storage battery, the lead dioxide which is an active material repeats expansion | swelling and shrinkage | contraction with repetition of charging / discharging. In addition, the uninterruptible power supply is used for an extremely long time as an emergency power source in the event of a power outage, and during this time, it is always charged by the trickle charge, so the grid of the positive electrode plate 2 is likely to be partially broken by corrosion, Even if the thickness of the grid of the positive electrode plate 2 is increased, the deterioration of the lead storage battery due to this corrosion cannot be completely avoided. Accordingly, in the positive electrode plate 2, when the lattice breaks, the grid spreads at the broken portion of the grid when the active material expands, and the size of the grid does not return when the active material contracts. become. That is, in the lead storage battery in which deterioration is in progress, the positive electrode plate 2 expands to the left and right until it is blocked by the inner surface of the battery case 6 as indicated by an arrow A in FIG. Further, since the upper right side of the positive electrode plate 2 is pressed against the positive electrode strap 5 via the ear portion 2a, the upper side on the left side is lifted upward as indicated by the arrow B, and is higher than the upper side of the separator 3. Expand. In this state, as shown by an arrow C in FIG. 6C, the upper side of the left side of the positive electrode plate 2 further expands to contact the negative electrode strap 4 and cause an internal short circuit.

  Therefore, in a lead storage battery used in a conventional uninterruptible power supply, a short-circuit prevention plate 7 made of an insulator is disposed between the positive electrode plate 2 and the negative electrode strap 4, and an internal short circuit due to expansion of the positive electrode plate 2 is performed. I was trying to prevent it. As shown in FIG. 5, the short-circuit prevention plate 7 is a resin plate formed in a comb shape, and has three tooth portions 7 a protruding from the base portion toward the right side or the left side. And the tooth | gear part 7a is inserted between the four ear | edge parts 1a of the negative electrode strap 4 and the negative electrode plate 1 under it. Therefore, as shown in FIG. 6A, the short-circuit prevention plate 7 is placed on the upper side of the separator 3, and each tooth portion 7a is interposed between the lower positive electrode plate 2 and the upper negative electrode strap 4. Since it is arranged so as to block, even if the upper left side of the positive electrode plate 2 extends beyond the upper side of the separator 3 as shown by an arrow C in FIG. 6C, the positive electrode plate 2 and the negative electrode strap 4 To prevent them from causing an internal short circuit.

  However, when the upper side of the left side of the positive electrode plate 2 expands and presses against the negative electrode strap 4 via the short-circuit prevention plate 7 as described above, the deterioration of the lead storage battery progresses considerably, and the battery capacity is 50% of the manufacturing capacity. It is thought that it has decreased to the following. For this reason, conventionally, the situation where the lead storage battery cannot be used immediately can be prevented by preventing the internal short circuit by the short-circuit prevention plate 7, but since the battery life of this lead storage battery has reached the end, Continuing the use has caused a problem that there is a possibility that sufficient power cannot be supplied in the event of a critical power failure.

  The present invention intends to provide a lead storage battery that can detect abnormal expansion of a positive electrode plate and determine that the battery life is at the end by arranging a pressure sensor on a short-circuit prevention plate or the like. .

  In the lead storage battery in which the positive electrode plate and the negative electrode plate are accommodated in the battery case via the separator, the pressure sensor is arranged outside the edge portion of the positive electrode plate in the battery case. Features.

  In the invention of claim 2, an insulating short-circuit prevention plate is disposed between the negative electrode strap connected to the ear portion of the negative electrode plate and the edge portion of the positive electrode plate laminated together with the negative electrode plate through the separator. In the lead-acid battery, a pressure sensor is arranged on either the front or back surface of the short-circuit prevention plate.

  According to the invention of claim 3, an insulating short-circuit prevention plate is disposed between the negative electrode strap connected to the ear portion of the negative electrode plate and the edge portion of the positive electrode plate laminated together with the negative electrode plate through the separator. In the lead storage battery, the short-circuit prevention plate is a plate material including an insulating pressure sensor or a pressure sensor covered with an insulating material.

  According to the first aspect of the present invention, since the pressure sensor is disposed outside the edge portion of the positive electrode plate, when the positive electrode plate expands, the pressure sensor is pressed between the inner surface of the battery case. Therefore, it is possible to detect whether or not the positive electrode plate is abnormally expanded by this pressure sensor, and it becomes possible to know the standard of the battery life.

  According to the invention of claim 2, since the pressure sensor is disposed on the short-circuit prevention plate, when the positive electrode plate expands, the pressure sensor is pressed between the negative electrode strap. Therefore, it is possible to detect whether or not the positive electrode plate is abnormally expanded by this pressure sensor, and it becomes possible to know the standard of the battery life. In addition, since the pressure sensor can be disposed in advance by being attached to the short-circuit prevention plate, it is not necessary to separately dispose the pressure sensor.

  According to the invention of claim 3, since a part or all of the short-circuit prevention plate is a pressure sensor, when the positive electrode plate is expanded, the pressure sensor is pressed between the negative electrode strap. Therefore, it is possible to detect whether or not the positive electrode plate is abnormally expanded by this pressure sensor, and it becomes possible to know the standard of the battery life. Moreover, since the pressure sensor is integrated with the short-circuit prevention plate, it is not necessary to separately arrange the pressure sensor.

  In addition, the pressure sensor according to claims 1, 2 and 3 always or appropriately detects, so that when the pressure becomes abnormal, the lamp is turned on or a message is displayed on the display unit to give a warning. Alternatively, for example, the pressure may be detected only when a detection circuit is connected to a terminal drawn to the outside.

  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 functions similar to those of the conventional example shown in FIGS.

  In the present embodiment, a lead storage battery used for the uninterruptible power supply similar to the conventional example shown in FIGS. The lead storage battery of the present embodiment has the same structure as the conventional example except that the pressure sensor 8 is disposed on the short-circuit prevention plate 7. Further, the short-circuit prevention plate 7 itself has the same configuration as that of the conventional example, and an insulating resin plate such as polypropylene is formed in a comb shape as shown in FIG. That is, in the case of the one shown in FIG. 1, the short-circuit prevention plate 7 is formed in a comb-like shape having three teeth 7a projecting from the base at the left end toward the right. The three tooth portions 7a are arranged in parallel in the front-rear direction at the same pitch as the three positive electrode plates 2 of the element, with an interval slightly wider than the thickness of the negative electrode plate 1 (ear portion 1a). Accordingly, each tooth portion 7 a has a width in the front-rear direction that is sufficiently wider than the thickness of the positive electrode plate 2. Further, the length in the left-right direction including the base portion of each tooth portion 7 a is sufficiently longer than the width in the left-right direction of the negative electrode strap 4.

  As in the case of the rear element shown in FIG. 5, the short-circuit prevention plate 7 is formed from the left side where the negative electrode plate 1 and the positive electrode plate 2 are laminated via the separator 3, and the separator 3 and the negative electrode strap above it. 4, the ear portions 1a of the two negative electrode plates 1 on the center side of the stack are inserted so as to be sandwiched between the respective tooth portions 7a. Therefore, as shown in FIG. 2, the short-circuit prevention plate 7 is placed on the upper side of the separator 3 below the negative strap 4 because the positive plate 2 is not expanded when inserted.

  A pressure sensor 8 is affixed in advance to the upper surface of the short-circuit prevention plate 7 near the base side of each tooth portion 7a. The pressure sensor 8 is made of a thin sheet of pressure-sensitive conductive rubber. Pressure-sensitive conductive rubber is a rubber material in which fine powder of conductive material such as carbon or metal is mixed with rubber, and the electrical resistance is usually extremely high, but the resistance value decreases rapidly when pressure is applied. . The pressure sensor 8 is a sheet-like thin sheet made of this pressure-sensitive conductive rubber. When the short-circuit prevention plate 7 is assembled, as shown in FIG. It is affixed on the upper surface of each tooth | gear part 7a which becomes a wide range. Further, the pressure sensor 8 is configured so that the width of the front and rear of the strip is wider than at least the width of the positive electrode plate 2 so as to reliably cover the upper side of the positive electrode plate 2 within the range of the left and right lengths of the strip. ing.

  Although not shown here, each pressure sensor 8 is provided with a pair of electrodes. The pair of electrodes is made of, for example, a metal thin film or the like formed on the lower surface of the pressure sensor 8 (or the upper surface of the short-circuit prevention plate 7), and is reliable even when only a part of the sheet-like pressure sensor 8 receives pressure. For example, it is formed in a pattern in which a pair of comb-shaped shapes face each other with a slight gap therebetween and meshed with each other. For example, a pair of electrodes may be formed in a matrix on the upper and lower surfaces of the pressure sensor 8. In this case, however, the electrode on the upper surface side of the pressure sensor 8 needs to be insulated from the negative strap 4 except when grounded to the negative electrode. A pair of electrodes of each pressure sensor 8 is drawn out of the lead-acid battery via lead wires or the like. At this time, if the pair of electrodes of each pressure sensor 8 are individually pulled out, the number of external terminals becomes too large. Therefore, the pair of pressure sensors 8 attached to the six short-circuit prevention plates 7 in each cell. The electrodes may be pulled out after being connected to each other in parallel, for example, or the pair of electrodes of all the pressure sensors 8 in the lead storage battery may be pulled out after being connected to each other in parallel, for example. In this embodiment, the pair of electrodes of the pressure sensor 8 drawn out of the lead storage battery is connected to a pressure detection circuit provided in the uninterruptible power supply. The pressure detection circuit is a circuit that turns on a warning lamp arranged on the panel portion of the uninterruptible power supply when the electrical resistance between the pair of electrodes of any one of the pressure sensors 8 decreases to a predetermined value or more.

  According to the above configuration, the upper side of the positive electrode plate 2 extends beyond the upper side of the separator 3 as shown by the arrow in FIG. 2, and the short-circuit prevention plate 7 is attached to the negative strap 4 as shown in FIG. The pressure sensor 8 on the upper surface of the short-circuit prevention plate 7 is pressed and the electrical resistance value between the electrodes is rapidly reduced. Then, since the pressure detection circuit of the uninterruptible power supply detects this decrease in electrical resistance and turns on the warning lamp, the user of the uninterruptible power supply sees that the warning lamp is lit and the life of the lead storage battery is at the end. Therefore, it becomes possible to take measures such as replacement of lead-acid batteries before they can no longer be used as an emergency power source in the event of an actual power failure.

  In the above-described embodiment, the pressure-sensitive conductive rubber is used as the pressure sensor 8. However, the type of pressure sensor is not limited as long as the pressure by the positive electrode plate 2 can be detected. For example, in the case of pressure-sensitive conductive rubber, the electric resistance changes according to the pressure, but it is also possible to use a rubber having a switching characteristic in which the electric resistance sharply changes when the pressure exceeds a predetermined pressure. In addition, a conductive resin or conductive rubber is disposed between a conductive surface such as a metal surface through a slight gap so that the conductive resin or the conductive rubber is made conductive by being bent by pressure. A touch panel switch or the like can also be used as a pressure sensor, and a diaphragm made of a metal plate can be used instead of the conductive resin or conductive rubber. Furthermore, once this pressure sensor receives a pressure above a predetermined level, it does not need to be restored even if the pressure drops thereafter. For example, a fragile conductive material is used, and if this conductive material is destroyed by pressure, the pressure sensor becomes conductive. It is also possible to use one that is blocked. Furthermore, this pressure sensor is not only for detection by change in electrical resistance or conduction / cutoff, but also for example, the capacitance between the electrodes changes due to the change in the distance between the electrodes due to pressure, for example. Also good. Furthermore, this pressure sensor may use a piezoelectric effect (piezo effect), and detects an electromotive force generated by distortion due to pressure, or detects a change in electrical resistance. Good (piezoresistive effect).

  Moreover, although the case where the short circuit prevention board 7 which formed the resin board in the comb-tooth shape was used was shown in the said embodiment, as long as it is an insulating sheet material, a board | plate material, etc., a material is arbitrary, the negative strap 4 and a positive electrode The shape of the short-circuit prevention plate is not limited as long as the shape can be interposed between the end edges of the plate 2. Furthermore, in the said embodiment, although the case where a pressure sensor was affixed on the upper surface of a short circuit prevention board was shown, you may affix on a lower surface. Furthermore, the pressure sensor can be formed in a film or layer on either the front or back surface of the short-circuit prevention plate, and a sheet material in which a layer of pressure-sensitive conductive rubber or the like is formed on the surface of an insulating substrate, What shape | molded the board | plate material etc. in the shape suitably can also be used as a short circuit prevention board and a pressure sensor.

  Moreover, in the said embodiment, although the case where the pressure sensor was arrange | positioned on either the front or back surface of a short circuit prevention board was shown, a part or all of a short circuit prevention board can also be comprised with a pressure sensor. For example, when the pressure sensor is insulative, the pressure sensor itself can be used as a short-circuit prevention plate, and a part of the short-circuit prevention plate can be constituted by this pressure sensor. Furthermore, when the pressure sensor is not insulating, it can be used as a short circuit prevention plate by covering it with an insulating layer, an insulating film, an insulation sheet, etc., and this pressure sensor is embedded in a part of the short circuit prevention plate. You can also

  In the above embodiment, the pressure detection circuit of the uninterruptible power supply device detects this when the pressure sensor receives a pressure higher than a predetermined pressure, and the warning lamp is turned on. It is optional, and instead of turning on the warning lamp, a message can be displayed on the display unit, or other control devices can be notified by communication. Furthermore, in the above embodiment, the case where the pressure detection circuit of the uninterruptible power supply detects the pressure of the pressure sensor constantly or appropriately is shown. However, for example, only when an operation such as pressing a detection switch is performed, The pressure may be detected, or the detection may be performed only when an operator connects a detection circuit to a terminal that has the electrode of the pressure sensor drawn out of the lead storage battery.

  Moreover, although the 6-cell lead storage battery was demonstrated in the said embodiment, this number of cells is arbitrary and the structure of the battery case which consists of a battery case and a cover plate is not limited to this. Further, the element is not limited to the laminated type, and the element can be similarly implemented even if it is a wound type in which the negative electrode plate and the positive electrode plate are wound through a separator. In the case where the element is a winding type, the ear portion is protruded from the cylindrical end face and connected to the strap, and for example, a disk-shaped short-circuit prevention plate may be disposed on the end face.

  Moreover, although the case where the pressure sensor was arrange | positioned to the short circuit prevention board was shown in the said embodiment, you may make it arrange | position a pressure sensor outside the edge part of the positive electrode plate in a battery case. For example, in the case of the above embodiment, if pressure sensors are attached to the left and right inner surfaces of the battery case 6, the positive electrode plate 2 expands to the left and right as shown in FIG. It is possible to detect that the inner surface of the tank 6 has been pressed. In addition, when the pressure sensor is arranged in the battery case as described above, the present invention can be implemented in a lead storage battery that does not use a short-circuit prevention plate or a lead storage battery that does not use a strap.

  Moreover, although the said embodiment demonstrated the lead storage battery used for an uninterruptible power supply, the use of this lead storage battery is not limited to this.

  FIGS. 3 and 4 show the results of actually producing the lead storage battery shown in the above embodiment and conducting a trickle life test. The lead-acid battery is a 12V, 17Ah (20HR) valve-regulated lead-acid battery, and the trickle life test was performed at a charge voltage of 2.275 V / cell in a 40 ° C. gas phase. FIG. 3 shows a change in the 0.25 CA discharge capacity with the lapse of the trickle charge period and a change in pressure due to the positive electrode plate 2 applied to the pressure sensor 8 (short-circuit prevention plate 7). FIG. 4 shows the result of FIG. 3 as a relationship between the pressure applied to the pressure sensor 8 and the 0.25 CA discharge capacity.

  As apparent from FIGS. 3 and 4, the pressure applied to the pressure sensor 8 increases linearly as the 0.25 CA discharge capacity decreases. Therefore, it was found that when the pressure applied to the pressure sensor 8 exceeds a predetermined level, it can be determined that the life of the lead-acid battery is at the end. Further, if the change in the pressure applied to the pressure sensor 8 is converted into a percentage of 0.25 CA discharge capacity based on, for example, FIG. 4 and displayed, an indication of how much the battery life of the lead storage battery remains is provided. It is also possible. Further, since the 0.25 CA discharge capacity and the pressure applied to the pressure sensor 8 are in such a linear relationship, for example, it is detected only that the positive electrode plate 2 touches the contact for inspection by expansion, and the battery life is detected. It has also been found that the battery life can be more accurately determined by performing detection based on the magnitude of the pressure applied to the pressure sensor 8 as in the above-described embodiment, rather than performing the determination.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of the present invention, and is a partial cross-sectional plan view illustrating a short-circuit prevention plate attached to an element. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of the present invention, and is a partial cross-sectional side view showing a short-circuit prevention plate attached to an element. It is a graph which shows the Example of this invention, and shows the change of the 0.25CA discharge capacity with progress of a trickle charge period, and the change of the pressure added to a pressure sensor. FIG. 5 is a graph illustrating an example of the present invention and representing a relationship between a pressure applied to the pressure sensor 8 and a 0.25 CA discharge capacity. It is a perspective view which shows a prior art example and shows the structure of the element of a lead storage battery. It is a longitudinal cross-sectional front view which shows a prior art example and shows the mode of expansion of the positive electrode plate in a lead acid battery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Negative electrode plate 1a Ear part 2 Positive electrode plate 2a Ear part 3 Separator 4 Negative electrode strap 5 Positive electrode strap 6 Battery case 7 Short-circuit prevention board 7a Tooth part 8 Pressure sensor

Claims (3)

In a lead storage battery in which a positive electrode plate and a negative electrode plate are housed in a battery case via a separator,
A lead-acid battery, wherein a pressure sensor is disposed outside the edge of the positive electrode plate in the battery case. In a lead-acid battery in which an insulating short-circuit prevention plate is disposed between a negative electrode strap connected to the ear portion of the negative electrode plate and an edge portion of the positive electrode plate laminated with a separator through the negative electrode plate,
A lead-acid battery, wherein a pressure sensor is disposed on either the front or back surface of the short-circuit prevention plate. In a lead-acid battery in which an insulating short-circuit prevention plate is disposed between a negative electrode strap connected to the ear portion of the negative electrode plate and an edge portion of the positive electrode plate laminated with a separator through the negative electrode plate,
The lead storage battery, wherein the short-circuit prevention plate is a plate material including an insulating pressure sensor or a pressure sensor covered with an insulating material.

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