JP6525167B2 - Lead storage battery - Google Patents

Description

  The present invention relates to a lead-acid battery, and more particularly to a lead-acid battery that suppresses an osmotic short circuit.

Lead-acid batteries are increasingly used in an incomplete state of charge (PSOC).
For example, in an idling stop vehicle (IS), the fuel consumption is reduced by stopping the engine each time the vehicle is stopped, and the engine is started by the power from the storage battery at the time of start. Therefore, the storage battery is used in a state of insufficient charge. In order to improve energy efficiency, charging of the storage battery is avoided and the power extracted from the storage battery is increasing, so that the storage battery is often placed in a state of insufficient charge.

In a lead-acid battery, sulfuric acid is consumed by the bipolar plate during discharge, water is generated in the positive electrode, sulfuric acid is released from the bipolar plate during charging, and a stratification phenomenon occurs in which sulfuric acid of high specific gravity is accumulated in the lower part. When the charge amount is sufficient (overcharge), the electrolyte is stirred by the gas generated from the electrode plate at the end of charge, and the concentration difference is eliminated.
However, in the lead storage battery used in PSOC, since the overcharge amount is small, it is difficult to eliminate the difference in concentration between the top and bottom, and stratification occurs. When the electrolytic solution is stratified, the charge / discharge reaction becomes nonuniform, and as a result, sulfation (accumulation of lead sulfate) progresses, and the softening and life performance of the positive electrode decrease.

Patent Document 1 "is suitable for an automobile having a long life and a large discharge capacity even when used under severe conditions such as repeated deep charge and discharge, and particularly introducing a new system such as idling stop and overcharge prevention. The object of the present invention is to provide a lead storage battery (paragraph [0010]), wherein an electrode is formed by alternately laminating a positive electrode plate using a Pb-Ca based alloy substrate and a negative electrode plate with a separator in between. In the lead storage battery in which a plate group is inserted in a battery case, the separator is felt-like, and the surface density is 20 to 100 g / m ² , and the thickness at a pressure of 20 kPa is 0.1 to 0.8 mm, A lead storage battery characterized in that at least one of a positive electrode plate or a negative electrode plate is accommodated in a synthetic resin bag, and the electrode plate group is inserted into the battery case with a compression degree of 10 to 25 kPa. Claim 1) is described There is.
As Example 1 of this lead storage battery, “a negative electrode prepared by a known method housed in a synthetic resin made bag (bag-like separator) based on a porous polyethylene sheet with a thickness of 0.25 mm in a positive electrode unformed plate An unformed sheet is laminated via a glass mat (felt-like separator), and the same electrode plates of this laminated body are welded by the COS method to form an electrode plate group. A 100 g / m ² , one having a thickness of 0.1 to 0.8 mm under a pressure of 20 kPa was used, and a glass mat made of a non-woven fabric of fine glass fibers was used as the felt-like separator. , [0021]).
And, in this lead-acid battery, the glass mat is inserted at an appropriate degree of compression, and by having an appropriate area density and thickness at the time of pressurization, the softening and falling of the active material is prevented, and the electrolyte is good. It is described that the effect of diffusing and suppressing stratification of the electrolytic solution is exhibited (paragraph [0012]).

In the case of a lead-acid battery used under severe conditions where the electrolyte surface level falls below the lower limit of the appropriate range, Patent Document 2 addresses the problem that the vicinity of the strap of the negative electrode plate ear is oxidized and corroded [0004]), "A porous body having corrosion resistance is disposed in close contact with the surface of the negative electrode plate ear" (claim 1).
And as an example, in order to prevent a short circuit between a positive electrode plate and a negative electrode plate, separator 3 and glass mat 4 are inserted, and after forming a strap by COS method, it consists of extra-fine glass fibers of about 1 micron in diameter. Inserting the mat-like body 6 in intimate contact with the ear surface of the negative electrode plate (paragraph [0009]) is described, and this lead-acid battery is a porous body having minute gaps in which the negative electrode plate ear holds the electrolyte. It is described as having the effect of suppressing corrosion due to oxidation because of close contact (paragraph [0015]).

According to Patent Document 3, "the time and effort for rehydration is saved, and the amount of electrolyte solution can be reduced to further reduce the weight, and furthermore, the initial capacity in slow discharge and the negative absorption lead acid battery with a control valve and An object of the present invention is to provide a battery in which the duration of low temperature rapid discharge does not decrease "(paragraph [0014]), and" a positive electrode plate and a negative electrode plate using a Pb-Ca alloy for the positive electrode grid and the negative electrode grid. A first separator made of a mat-like sheet-formed body mainly made of acid resistant fibers such as glass fibers so as to be in contact with at least the negative electrode plate surface in the upper portion of the electrode plate group; The lead storage battery is characterized in that the lower part of the electrode plate group excluding the upper part of the group is not provided with the first separator, and is provided with a second separator made of a microporous film of acid resistant resin such as polyethylene. , “On the plate group Between the positive electrode plate and the negative electrode plate is a three-layer separator, which is composed of a central layer composed of the second separator and an outer layer composed of the first separator, which is disposed on both outer sides of the central layer. "A lead-acid battery according to the present invention is characterized in that only the central layer formed of the second separator is disposed between the positive electrode plate and the negative electrode plate in the lower part of the electrode plate group. It is described about.
In this lead-acid battery, even when the electrolyte surface is lowered and the negative electrode plate is exposed from the electrolyte surface, the electrolyte is applied to the negative electrode plate from the mat separator (first separator) arranged to be in contact with the upper portion of the negative electrode plate. Since it is supplied, an oxygen gas absorption reaction proceeds in this portion, and it is described as having an effect that oxidation of the negative electrode plate and reduction of water content are suppressed (paragraph [0020]).

  According to Patent Document 4, in the case of a lead-acid battery which is used in a severe manner, the base of the separator and the anode come in contact, and a problem arises that the separator has a hole and the penetration shorts due to oxidation (page 1 right column The invention is described in which a separator is provided with a glass mat in the portion corresponding to the upper part of the anode plate, line 15 to page 2, upper left column (line 3) (claim (1)).

JP, 2006-100082, A Unexamined-Japanese-Patent No. 4-249064 JP 2007-87871 A Unexamined-Japanese-Patent No. 4-95342

  In a battery for PSOC application, there is a problem that the specific gravity of the electrolytic solution tends to decrease due to the stratification, and a micro short circuit occurs accordingly. The inventor found that, as the specific gravity of the electrolyte decreases, the concentration of lead ions in the electrolyte increases, and in the subsequent charging process, the lead ions are reduced to precipitate lead crystals. As a result, between the negative electrode plate and the positive electrode plate It is thought that the phenomenon that a minute conduction part is born has occurred.

  On the other hand, as a method of manufacturing a lead storage battery, strap formation by the COS system may be performed. In the COS method, molten lead obtained by melting lead or lead alloy is poured into the recess of a mold in which a recess having the same shape as the strap is engraved, and the tip of the electrode plate ear of the same polarity is dipped in the lead. After melting the ear with the heat of the lead, it is solidified by cooling and integrated with the ear.

In order to ensure welding between the ear and the strap in the COS system, a gap into which molten lead flows into the outside of the ears on both ends of the same electrode plate is necessary. The length A between the outer ends (hereinafter referred to as “ear group length A immediately below the strap” or “ear group length A” and simply “length A” or “A”) is the length of the recess of the mold. Length, ie shorter than the strap length.
In addition, in the COS system, when the thickness of the electrode plate group in the stacking direction becomes considerably long by, for example, thickening the electrode plate when the shape of the mold is not changed, the upper portion of the electrode plate group shown in FIG. More specifically, the length B between the outer edges of the upper frame bone portions in the current collectors of the electrode plates located at both ends of the electrode plates connected to the straps (hereinafter referred to as “dimension B in the lamination direction in The upper electrode plate group length B is called, and simply "length B" or "B" is longer than the ear group length A just below the strap.

  The inventor has found that the occurrence of the above-mentioned osmotic short circuit is a phenomenon that the frequency is high particularly near the upper end among the upper portions of the electrode plate group, and further, the ear group length A and the upper electrode plate group length B As a result of examining the magnitude relationship, it was found that the above phenomenon becomes remarkable when A <B. Moreover, in addition to such a thing, this inventor also discovered that the low-temperature high-rate discharge characteristic improves, although the penetration short circuit performance falls, when it is A <B. When A ≧ B, the osmotic short circuit is suppressed as compared with the case of A <B. However, in order to make A ≧ B, it is necessary to make the strap larger than in the case where A <B, and as a result, for example, the material cost becomes high, the mold needs to be updated, or It may happen that it becomes difficult to store in a battery case of a predetermined size as defined in JIS D5301.

The lead storage battery described in Patent Document 1 has a felt-like separator (glass mat) in addition to the synthetic resin bag-like separator between the positive electrode plate and the negative electrode plate adjacent to each other (hereinafter also referred to as "inter-electrode"). Moreover, the lead storage battery described in Patent Document 2 has a mat-like body 6 made of a glass mat 4 and an ultrafine glass fiber, in addition to the separator 3, between the electrodes.
However, when the electrode plate ear and the strap are welded by the COS method and the ear group length A and the upper electrode plate group length B satisfy A <B, the problem that the permeation short circuit resistance performance is not recognized is not recognized.

  The lead storage batteries described in Patent Documents 3 and 4 have a resin separator (second separator or synthetic resin separator) between the electrodes, and either the separator or the positive or negative separator above the electrode plate group. A glass mat is provided between the plates. However, the COS system is not described, and nothing is suggested about the magnitude relationship between the ear group length A immediately below the strap and the upper electrode plate group length B.

  This invention makes it the issue which should be solved to improve a penetration short circuit performance in a lead storage battery which is A <B.

The present invention has the following means in order to solve the problems described above.
The first invention is a lead-acid battery including an electrode plate group in which a positive electrode plate and a negative electrode plate are stacked via a separator, an electrolytic solution, and a battery case in which the electrode plate group is housed.
The upper frame bone portion of the electrode plate located at both ends of the electrode plate connected to the at least one strap, with the length A between the outer ends of the ears at both ends of at least one of the positive and negative straps directly below the strap Less than the length B between the outer end faces of the
A porous layer is provided between at least one of the separator and the positive electrode plate or between the separator and the negative electrode plate ,
The porous layer is a mat containing a resin as a main component .

The second invention is characterized in that, in the first invention, a difference between the length A and the length B is 1 mm or more .
The third invention of the present invention is a lead storage battery including an electrode plate group in which a positive electrode plate and a negative electrode plate are laminated via a separator, an electrolytic solution, and a battery case containing the electrode plate group,
The upper frame bone of the electrode plate located at both ends of the electrode plate connected to the at least one strap, with the length A between the outer ends of the ears at both ends of the positive electrode strap or the negative electrode strap directly below the at least one strap. Smaller than the length B between the lamination direction outer ends of the parts,
A porous layer is provided between at least one of the separator and the positive electrode plate or between the separator and the negative electrode plate,
The difference between the length A and the length B is 1 mm or more .

The present fourth invention, in any one of the first to third invention, characterized that you have the porous layer is provided on the negative electrode plates and the separator, the fifth invention, the first to In any of the three inventions, the porous layer is provided on both of the separator and the positive electrode plate and between the separator and the negative electrode plate .

The sixth invention is characterized in that, in any one of the first to fifth inventions , the thickness of the porous layer is 0.1 mm or more, and the seventh invention is any of the first to sixth inventions. in addition, the portion exceeding 50% of the contacting area plates of the porous layer, characterized that you present in a region within 50% above the electrode plate group.

The eighth invention is characterized in that in the lead storage battery according to any one of the first to seventh inventions , the osmotic short circuit in the upper portion of the electrode plate is suppressed , and the ninth invention is characterized by the first to eighth inventions. In any of the inventions, the lead storage battery is a lead storage battery for an idling stop car.

According to the first to eighth inventions, it is possible to provide a lead-acid battery in which the osmotic short circuit is suppressed.
According to the fifth and sixth inventions, it is possible to provide a lead-acid battery in which the osmotic short circuit is more effectively suppressed.
According to the seventh invention, it is possible to provide a lead-acid battery in which the osmotic short circuit is suppressed while maintaining the high rate discharge performance at low temperature.
According to the ninth aspect of the present invention, it is possible to provide a lead storage battery for an idling stop car with suppressed osmotic short circuit and sufficient PSOC life performance.

Conceptual diagram of sulfuric acid specific gravity gradient between poles at the time of discharge in the present invention and the prior art Explanation of ear group length A and upper plate group length B just below the strap An illustration of an expanded type current collector Illustration of cast type current collector An illustration of the porous layer installation position Graph showing the relationship between the thickness of the porous layer, the contact ratio with the electrode plate, and the occurrence rate of osmotic short circuit Graph showing the relationship between the thickness of the porous layer, the contact ratio with the electrode plate, and the low-temperature high-rate discharge performance

  Hereinafter, embodiments of the present invention will be described. In practicing the present invention, the embodiment can be appropriately modified in accordance with the common knowledge of the person skilled in the art and the disclosure of the prior art. Hereinafter, the negative electrode material is referred to as a negative electrode active material, and the positive electrode material is referred to as a positive electrode active material. The negative electrode plate comprises a negative electrode current collector and a negative electrode active material, the positive electrode plate comprises a positive electrode current collector and a positive electrode active material (positive electrode active material), and solid components other than the current collector are active material (electrode It belongs to material).

  The lead-acid battery according to the present invention includes, for example, an electrode plate group including a negative electrode plate containing lead as an active material, a positive electrode plate containing lead dioxide as an active material, and a porous separator interposed between these electrode plates. The electrode group is accommodated in the battery case, and is immersed in a flowable electrolytic solution mainly composed of dilute sulfuric acid.

  The negative electrode plate and the positive electrode plate are formed by filling a paste-like active material in a lattice portion of a current collector made of Pb-Sb alloy, Pb-Ca alloy, Pb-Ca-Sn alloy, etc. It is. Each of these constituent members can be appropriately selected from known ones in accordance with the purpose and application.

  In the case of the expanded type shown in FIG. 3, the current collector protrudes from the lattice portion filled with the active material, the upper frame bone portion continuously connected to the edge of the lattice portion, the lower frame bone portion, and the upper frame bone portion Have an ear to In the case of the casting type shown in FIG. 4, the frame further includes a foot projecting from the lateral frame bone and the lower frame bone.

  The separator in the present invention separates the positive electrode plate and the negative electrode plate, and a separator generally used as a liquid lead-acid battery separator can be used. In the present invention, as the separator, for example, a sheet mainly composed of polyolefin having fine pores, or a mat mainly composed of fibers of resin or glass can be used, and in particular, it is fine in terms of handleability and cost. It is preferable to use a sheet having polyethylene as a main component having holes. A sheet mainly composed of a polyolefin having micropores tends to precipitate lead metal inside the micropores, as compared with a mat mainly composed of fibers of resin or glass, and therefore, it is significant in the present invention. The shape of the separator may be bag-like or flat. In the case of a bag-like separator, either the positive electrode plate or the negative electrode plate may be accommodated in the bag.

  In the present invention, the positive electrode plate and the negative electrode plate are laminated via a separator, and a porous layer is provided at least between the positive electrode plate and the separator or between the separator and the negative electrode plate. The porous layer may be anything as long as it has a function of separating the surface of the electrode plate near the top and the surface of the separator. From the viewpoint of oxidation resistance, it is preferable to use the same material as the separator used in the present invention. The porous layer of the present invention is preferably porous, and by making it porous, the flowability of the electrolyte solution in the interior can be improved as compared with the one without pores. As the porous layer of the present invention, specifically, a porous synthetic resin film or a mat made of glass can be used. Since the glass mat has a function of holding the electrolyte and appropriately preventing the diffusion, it is considered that the stratification due to the precipitation of sulfuric acid at the time of charge can be reduced.

In the lead-acid battery of the present invention, the ear group length A immediately below at least one of the positive electrode strap and the negative electrode strap is smaller than the upper electrode plate group length B of the electrode plate connected to the at least one strap. This length A is a length between the outer ends of the ears at both ends in contact with the lower surface of the strap, as shown in FIG. The length B is, as shown in FIG. 2, the length between the lamination direction outer ends of the upper frame bone portions of the current collectors of the electrode plates located at both ends of the electrode plates connected to the strap. The length A and the length B are dimensions measured after the electrode plate group is stored in the battery case and formed, and in the fully charged state. The measurement of this dimension can be performed in a state in which the electrode plate group is taken out of the battery case, as long as the dimension in the stacking direction of the electrode plate group is substantially the same as the dimension when stored in the battery case.
In the present invention, by setting A <B, the strap can be miniaturized. As a result, for example, the material cost is reduced, and it is not necessary to change the mold even if the size of the electrode plate group changes, or the electrode plate group elongated in the stacking direction by being filled with more active material There is an effect that it becomes possible to store in a battery case of a predetermined size as defined in JIS D5301. In the present invention, the difference between the length A and the length B can be 1 mm or more, and preferably 3 mm or more because the effect of the present invention is remarkable.

The porous layer of the present invention has the effect of suppressing the occurrence of the permeation short circuit by being interposed between the separator and the electrode plate. This effect is considered to be caused by preventing the contact of the electrode surface with the separator, and the contact of the separator with the low specific gravity region assumed to be on the surface of the electrode plate and in the vicinity thereof. The above effect is remarkably recognized when the relationship between the length A and the length B is A <B. This is because, in this case, the frequency of occurrence of the osmotic short circuit on the electrode plate is higher than that in the case of A ≧ B, that is, the effect of suppressing the osmotic short circuit by the porous layer is clearly recognized. In the case of A 浸透 B, such an osmotic short circuit does not occur at all or infrequently, and the phenomenon that occurs in the upper part of the electrode group especially near the upper end has not been known so far. It is considered that the manufacturer or the user without such recognition does not recognize the phenomenon to such an extent that it can be distinguished from the osmotic short circuit and failure cause in other places.
In the present invention, by providing the porous layer and satisfying A <B, it is possible to simultaneously suppress the permeation short at the top of the electrode plate and to obtain the effect that the strap can be miniaturized. By setting A <B, it is a phenomenon which the inventor found for the first time that concentrated short circuit occurs intensively in a limited part of the upper frame bone peripheral part of the upper part of the electrode plate, so use a porous layer The effect that such a problem can be improved can be said to have been recognized by the inventor for the first time.

The present invention is preferably applied to a lead storage battery for an idling stop vehicle. Because lead storage batteries for idling stop vehicles are used under PSOC conditions, there is a high probability that an osmotic short circuit will occur compared to batteries for other uses, and as a result, the significance of applying the present invention is great. .
In addition, there is also an effect obtained for the first time by applying the present invention to a lead storage battery for an idling stop car. Lead-acid batteries for idling stop cars require more active material to achieve higher charge acceptance performance than those for non-idling stop car applications, and as a result, the dimension in the stacking direction of the electrode plate group ( For example, length B) tends to be large. In the case of producing a battery using such an electrode plate group, when A = B or A> B, the strap becomes large in size, which makes it difficult to be stored in the battery case is there. In particular, since the upper limit of the battery size of the battery of the type specified in JIS D5301 is set, if the strap is too long, the battery may not be manufactured substantially. On the other hand, when A <B, there is no need to increase the size of the strap, so even if the dimension in the stacking direction of the electrode plate group is increased, the problem of difficulty in storing in the battery case is solved It becomes possible. Therefore, in the present invention, the porous layer is provided, A <B, and by using as a lead storage battery for an idling stop car, the effect of suppressing the osmotic short circuit in the upper part of the electrode plate and the strap are small. At the same time, it is possible to simultaneously obtain an effect that can be realized and an effect that enables a design in which an electrode group suitable for an idling stop car application can be accommodated in a limited space in a battery case. That is, only by adopting the present invention, the penetration short circuit in the upper part of the electrode plate is suppressed, and it becomes possible to manufacture a lead-acid battery having an active material mass sufficient as a lead-acid battery for an idling stop car.

  When a glass mat is used as the porous layer in the present invention, the average fiber diameter of the glass fiber is preferably 1.2 μm or more and 25 μm or less. By setting the thickness to 1.2 μm or more, it is possible to suppress the tendency of the high rate discharge performance and the charge acceptance to decrease, and by setting the size to 25 μm or less, the life performance can be greatly improved.

  In the present invention, in the plurality of electrode plates constituting the electrode plate group, the ears of the electrode plates of the same polarity can be connected by welding according to the COS system to be integrated. A portion formed by welding and integrating the ears of a plurality of electrode plates is a strap, and in the strap, when there are a plurality of cell chambers in the battery case, an inter-cell connection portion for connecting adjacent battery cells, and a battery The pole terminals connected to the terminals of the are connected in series. When the battery case has a single cell structure, a pole post is connected to the strap.

  The strap, the inter-cell connection portion, and the pole column are formed using, for example, a Pb--Sn alloy, a Pb--Sb alloy, or the like.

  In the present invention, the ear group length A immediately below the strap is smaller than the upper electrode plate group length B by forming the strap by the COS system, and a porous layer is provided at least one of between the separator and the positive electrode plate or between the separator and the negative electrode plate There is. Ear group length A is the length between the outer end faces of the ears located at both ends of the ears connected to the strap, as shown in FIG. The upper electrode plate group length B is a length between the lamination direction outer ends of upper frame bone portions of the electrode plates located at both ends of the electrode plates connected to the straps, as shown in FIG.

The action and mechanism by which the present invention improves the permeation short circuit performance is presumed as follows.
In a lead storage battery used in PSOC, it is likely to be in an overdischarged state, and sulfuric acid is consumed near the surface of the electrode plate by a discharge reaction, resulting in a low specific gravity region of the electrolytic solution. If the ear group length A and the upper electrode plate group length B immediately below the strap of the lead storage battery adopting the COS system are A <B, as shown in the left diagram of FIG. Because of this, the separator can not be separated from the low specific gravity area. In an electrolyte of low specific gravity, the amount of lead ions increases, and the lead ions are reduced and precipitated at the negative electrode during charging to grow dendrites and accelerate the permeation short circuit in which lead penetrates into the separator. In the present invention, by providing the porous layer, as shown in the right figure in FIG. 1, the separator can be separated from the low specific gravity region near the electrode plate surface, so the lead ion concentration on the separator surface and inside is difficult to increase. It is presumed that the occurrence of a short circuit can be suppressed.

  In the present invention, the porous layer is preferably provided between the positive electrode plate and the separator and between the separator and the negative electrode plate. By providing on both sides of the separator, the permeation short circuit resistance can be improved as compared to the case of providing on one side. This maintains the position of the separator near the center of the electrode and maintains the distance between the separator and the reaction surface of the positive and negative electrodes, thereby further suppressing the growth of dendrite in the separator and preventing permeation. It is presumed that the short circuitability can be further improved.

  In the present invention, the thickness of the porous layer is preferably 0.05 mm or more because the effect of suppressing the osmotic short circuit is surely exhibited as shown in the examples described later, and the effect of suppressing the osmotic short circuit is It is preferable that it is 0.1 mm or more from which it becomes excellent. It is inferred that the separator can be separated from the low specific gravity area at an appropriate distance because the porous layer is not too thin. Moreover, in order to fit between electrodes, it is preferable that thickness is 0.3 mm or less. The thickness is measured in a state of applying a pressure of 19.6 KPa according to the battery industry standard SBA S 0406.

In the present invention, in the porous layer, preferably, a portion exceeding 50% of the area of the porous layer in contact with the electrode plate is present in the region within the upper 50% of the electrode plate group. The upper part of the plate group is based on the height of the grid part of the plate. Therefore, it is preferable that the portion of the porous layer is present in the region corresponding to the upper 50% of the lattice portion.
The porous layer is not limited to the upper portion of the electrode plate group, and it has a certain effect on the permeation short circuit performance regardless of the region where it is present. However, it is more effective and preferable to have the porous layer at the top. This is because by disposing the porous layer in the upper part of the electrode plate group, the separator can be separated from the low specific gravity area of the electrolyte near the surface of the electrode plate more reliably than in the case of being disposed in the lower part. Moreover, it is considered that due to the stratification, the upper specific gravity region is lower than the lower specific gravity region and the occurrence of the osmotic short circuit is more likely to occur. In addition, when the porous layer is disposed on the upper part of the positive electrode plate, the ion conduction resistance at the upper part of the electrode plate is increased, and charging and discharging approaches uniformly occurring regardless of the upper and lower sides of the electrode plate. It is surmised that the softening and falling off of the electrolyte can be suppressed, and the stratification of the electrolytic solution can also be suppressed.

The porous layer preferably has a portion exceeding 50% of the area of the porous layer in contact with the electrode plate, in a region within the upper 40% of the electrode plate group. That is, it is preferable that the portion of the porous layer is present in the region corresponding to within the upper 40% of the grid portion of the electrode plate. Specifically, as shown in the right figure of FIG. 5, it may exist on the entire surface within the upper 40% of the height L of the lattice portion, or as shown in the left figure, it may be one of the areas within 40%. It may exist in the department. Further, as shown by the dotted line, if the above-mentioned portion of the porous layer is present in the region within the upper 40%, it may be present beyond the region within the upper 40% or may be provided in a dispersed manner. The same is true when the above portion of the porous layer is present in the region within the upper 50%.
If the ratio of existence of the porous layer between the electrodes is low, the effect of suppressing the osmotic short circuit is considered to be reduced because the effect of separating the separator from the low specific gravity region of the electrode plate surface is small. However, the lower the ratio of the porous layer between the electrodes, the smaller the increase in reaction resistance between the electrodes, so the decrease in initial performance is reduced, and the decrease in low-temperature high-rate discharge performance and chargeability is reduced. It is guessed that it can be done.

Hereinafter, Examples and Comparative Examples of the present invention will be shown.
<Example: A2-A33 battery>
(Positive electrode active material)
The positive electrode paste was prepared by mixing lead oxide by a ball mill method, synthetic resin fiber of reinforcing material, water and sulfuric acid. This paste is filled in an expanded type grid-like positive electrode current collector made of an antimony-free Pb-Ca-Sn alloy, aged and dried to obtain a 100 mm wide, 110 mm high, 1.6 mm thick non-woven material. A positive electrode plate of formation was produced.

(Anode active material)
A negative electrode paste was prepared by mixing lead oxide, flaky graphite, barium sulfate, lignin, and synthetic resin fibers of a reinforcing material by a ball mill method, water and sulfuric acid. This paste is filled in an expanded type negative electrode grid made of an antimony-free Pb-Ca-Sn alloy, aged and dried to give an unformed negative electrode plate 100 mm wide, 110 mm high and 1.3 mm thick. Made. In addition, the mixing amounts of scale-like graphite, barium sulfate, lignin and synthetic resin fibers are 2 mass%, 0.6 mass%, 0.2 mass% and 0.1 mass%, respectively, when measured after formation and in a fully charged state. Adjusted to%.

(Separator)
A bag-shaped separator made of synthetic resin is prepared, which is based on a polyethylene sheet with a base thickness of 0.2 mm and a rib height of 0.3 mm, and the negative electrode plate is housed in this bag, and the positive electrode plate is opposed to the rib I did.

(Battery configuration)
The six positive electrode plates and the seven negative electrode plates accommodated in the bag-like separator were alternately stacked so that the negative electrode plates were on the outside. As shown in Table 2, in one or both of the separator and the positive electrode plate or between the separator and the negative electrode plate, a glass mat having a porous layer thickness shown in the table is installed at the porous layer abutting position in the table. did. The glass mat was installed in such a manner that the ratio of the contact area to the total area of the grid and the ratio of the contact length to the height L of the grid are the same (see the right figure in FIG. 5. For example, the grid). When the area ratio from the top is 40%, the distance from the upper end of the upper frame to the lower 40% (the distance from the lower end of the lower frame to 100%) It means that it is installed so as to cover all the surface of the electrode plate in the range up to
An electrode plate group manufactured so that A <B is produced by welding the ears of the positive plates and the ears of the negative plates with the positive electrode strap and the negative electrode strap respectively according to the COS system is housed in a polypropylene battery case Sulfuric acid was added and battery case formation was performed to prepare liquid electrolyte lead-acid batteries A2 to A33, which are liquid lead-acid batteries having an electrolytic solution specific gravity of 1.285 and a 5 hR capacity of 30 Ah after the formation. In the battery case, six electrode plate groups are connected in series. In addition, a battery for checking the dimensions is separately prepared, and after battery formation, the battery is fully charged, and then the lid is removed to measure the ear group length A and the upper electrode plate group length B on the positive electrode side and the negative electrode side. did. About the thing from which the positive electrode side and the negative electrode side are set to A <B, it described with "A <B" in the following table | surfaces. About the thing from which the positive electrode side and the negative electrode side are set to A = B, it described with "A = B" in the following table | surfaces. About the thing from which the positive electrode side and the negative electrode side are set to A> B, it described with "A>B" in the following table | surfaces.

(Low temperature high rate discharge performance test)
After placing the above-mentioned liquid lead storage battery fully charged fully in the cooling chamber at -15 ° C ± 1 ° C for 16 hours or more, the discharge time until the terminal voltage dropped to 6 V was recorded at a discharge current of 150 A (JIS According to D5301's high rate discharge characteristics test).

(Penetration short circuit test)
A liquid lead-acid battery is newly prepared separately from one which has been subjected to the low-temperature high-rate discharge performance test, and after performing steps 1 to 5 shown in Table 1 in a thermostatic water bath at 25 ° C. I checked the existence. Twenty lead-acid batteries were tested for each example and comparative example to evaluate the incidence of osmotic short circuit.

Comparative Example 1
An A1 battery according to Comparative Example 1 was produced in the same manner as in the example except that the glass mat was not installed.

<Comparative Examples 2 and 3>
An X battery and a Y battery were produced in the same manner as in Comparative Example 1 except that the thickness of the electrode plate was reduced and the electrode plate group was produced such that A> B or A = B.

The characteristics of A1 to A33, and X and Y batteries are shown in Table 2.
“Low-temperature HR performance” in Table 2 indicates a ratio in which the discharge time of the A1 battery is 100% in the above-described low-temperature high-rate discharge performance test. “Permeation short circuit incidence rate” shows the value in 5% increments.

From the results shown in Table 2, A2 to A33 batteries in which the porous layer is provided on at least one of the separator and the positive electrode plate or between the separator and the negative electrode plate are effective in suppressing permeation short circuit as compared with the A1 battery in which the porous layer is not provided. I understand that. The effect obtained in A32 and A33 means that even when the porous layer is disposed only in the lower part, it has an effect of widening the distance between the separator and the electrode plate in the upper part. It is considered that the reason for this is that the distance between the separator and the electrode plate in the lower portion of the electrode plate is increased and the distance in the upper portion is also expanded under the situation where the contact between the strap and the ear acts as a fulcrum. Therefore, the porous layer does not have to be disposed near the upper end, and it can be said that the effects of the present invention can be obtained regardless of the position.
Further, from the results shown in Table 2, A2 to A9 batteries in which the porous layer is provided only on one of the separator and the positive electrode plate or between the separator and the negative electrode plate are also effective in suppressing permeation shorting compared to the A1 battery in which the porous layer is not provided. I understand that there is.
Further, from the results shown in Table 2, when the porous layer contact position and the porous layer thickness are compared under the same conditions, both between the separator and the positive electrode plate, and between the separator and the negative electrode plate than the battery of A2 to A9. It can be seen that the batteries of A10 to A31 provided with the porous layer on are more effective in suppressing the permeation short circuit. This means that the effects of the present invention become remarkable by arranging the porous layers on both sides.
Further, it can be seen that in the batteries of A18 to A21 in which the porous layer is provided in the range of 30% from the upper part, the osmotic short circuit is suppressed as compared with A32 and A33 in which the porous layer is provided in the range of 30% from the lower part.

  Also, looking at the batteries A2 to A31, a battery with a large contact area ratio of the porous layer from the upper part of the electrode plate is effective in the suppression of permeation short circuit, but the contact area ratio is not too large Was found to be preferable for maintaining low temperature high rate discharge performance.

6 and 7 show permeation when the thickness of the porous layer and the contact area ratio are changed in the battery of the present invention in which the porous layer is provided in both of the separator and the positive electrode plate and between the separator and the negative electrode plate. The changes in the short circuit incidence rate and the low temperature high rate discharge performance (low temperature HR performance ratio to the A1 cell) are shown together with the case of the A1 cell without the porous layer.
From FIG. 6, when the thickness of the porous layer is 0.1 mm or more and the contact area ratio from the top of the electrode plate is 20% or more, the occurrence rate of permeation short circuit is excellent as 30% or less, and the contact area It can be seen that increasing it does not significantly affect the reduction in the incidence of osmotic short circuit.
On the other hand, it can be seen from FIG. 7 that a low temperature HR performance ratio of 90% or more can be maintained for the A1 battery in which the porous layer is not provided when the contact area ratio from the top of the electrode plate is 40% or less. Accordingly, the porous layer preferably has a thickness of 0.1 mm or more, and is preferably provided within the upper 40% of the electrode plate group.

  In addition, in order to verify the effect when the battery of the present invention is used as a lead-acid battery for start-up for idling stop vehicles, it is substantially the same as the A23 battery except for the A23 battery which is an embodiment of the present invention. A life test was performed on the A1 battery of the same configuration, and the results were compared. The life test was performed by placing each battery in a 40 ° C. constant temperature bath and repeating the contents of steps 1 to 10 listed in Table 3 below. The conditions of each process are as the test condition column of Table 3. The life was evaluated by comparing the number of cycles when the terminal voltage reached 10.5 V. Here, the number of cycles is counted as one cycle of performing steps 1 to 5 once. The charge / discharge test conditions in Table 3 are representative charge / discharge patterns of the lead storage battery mounted on the idling stop car, and by performing this test, the life performance as a lead storage battery for the idling stop car (so-called Lifetime performance under PSOC conditions can be evaluated. As a result of the life test, the number of cycles when the terminal voltage of the A23 battery reached 7.2 V was about 10% more than that of the A1 battery. From this result, when a lead storage battery having a porous layer and having a configuration of A <B is used as a lead storage battery for an idling stop vehicle, the effect of suppressing the penetration short circuit in the upper part of the electrode plate and the strap are miniaturized. It can be said that it is possible to simultaneously obtain the effect that can be done and the effect of prolonging the life required for an idling stop car.

  Since the present invention separates the distance between the separator and the electrode plate and suppresses the osmotic short circuit when the ear group length A immediately below the strap is smaller than the upper electrode plate group length B, the opportunity for use in PSOC It is expected to be applied to lead-acid batteries etc. for many IS applications.

Ear group length immediately below A strap B Length between stacked outer ends of upper frame bones in electrode plates located at both ends (upper electrode plate group length)

Claims (9)

A lead storage battery comprising: an electrode plate group in which a positive electrode plate and a negative electrode plate are laminated via a separator; an electrolytic solution; and a battery case containing the electrode plate group,
The upper frame bone of the electrode plate located at both ends of the electrode plate connected to the at least one strap, with the length A between the outer ends of the ears at both ends of the positive electrode strap or the negative electrode strap directly below the at least one strap. Smaller than the length B between the lamination direction outer ends of the parts,
A porous layer is provided between at least one of the separator and the positive electrode plate or between the separator and the negative electrode plate ,
The lead storage battery characterized in that the porous layer is a resin-based mat . The lead storage battery according to claim 1, wherein a difference between the length A and the length B is 1 mm or more. A lead storage battery comprising: an electrode plate group in which a positive electrode plate and a negative electrode plate are laminated via a separator; an electrolytic solution; and a battery case containing the electrode plate group,
The upper frame bone of the electrode plate located at both ends of the electrode plate connected to the at least one strap, with the length A between the outer ends of the ears at both ends of the positive electrode strap or the negative electrode strap directly below the at least one strap. Smaller than the length B between the lamination direction outer ends of the parts,
A porous layer is provided between at least one of the separator and the positive electrode plate or between the separator and the negative electrode plate,
The lead storage battery characterized in that a difference between the length A and the length B is 1 mm or more. The lead storage battery according to any one of claims 1 to 3 , wherein the porous layer is provided between the separator and the negative electrode plate. The lead storage battery according to any one of claims 1 to 3 , wherein the porous layer is provided both between the separator and the positive electrode plate and between the separator and the negative electrode plate. The thickness of the said porous layer is 0.1 mm or more, The lead storage battery in any one of the Claims 1-5 characterized by the above-mentioned. The lead according to any one of claims 1 to 6 , wherein a portion exceeding 50% of the area of the porous layer in contact with the electrode plate is present in a region within the upper 50% of the electrode plate group. Storage battery. The lead storage battery according to any one of claims 1 to 7 , wherein an osmotic short circuit at the top of the plate is suppressed. The lead storage battery according to any one of claims 1 to 8 , which is a lead storage battery for an idling stop vehicle.