JP2015018628A - Control valve type lead storage battery and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control valve type lead storage battery having an improved cycle life and a method of manufacturing the same.SOLUTION: A control valve type lead storage battery includes a negative electrode plate, a positive electrode plate, a separator disposed between the negative electrode plate and the positive electrode plate, and an electrolyte, where 100.0 to 106.5 vol.% of the electrolyte is poured relative to a whole hole volume of the negative electrode plate, the positive electrode plate, and the separator. A method of manufacturing a control valve type lead storage battery includes the steps of accommodating, in a battery jar, an electrode plate group obtained by alternately laminating a negative electrode plate and a positive electrode plate via a separator, pouring an electrolyte, and forming the battery jar, where the electrolyte is poured such that its content after the formation of the battery jar becomes 100.0 to 106.5 vol.% relative to the whole hole volume of the negative electrode plate, the positive electrode plate, and the separator.

Description

  The present invention relates to a control valve type lead storage battery and a method for manufacturing the same.

  In the field of secondary batteries, a negative valve plate and a positive electrode plate each containing an active material, a mat separator interposed between the positive electrode plate and the negative electrode plate, and a control valve type lead storage battery including an electrolytic solution are known. Although the control valve type lead-acid battery is finally sealed and used, in order to prevent scattering of the electrolyte before sealing in the manufacturing process, the electrolyte has conventionally been made up of all of the negative electrode plate, the positive electrode plate and the separator. It was contained in an amount of 90 to 95% with respect to the pore volume, and the mat separator retained the electrolytic solution (Patent Document 1).

  In such a control valve type lead-acid battery, when charging / discharging is repeated, the discharge capacity is reduced early and the cycle life is reduced.

Japanese Patent Publication No. 4-57072

  An object of this invention is to provide the control valve type lead acid battery which improved the cycle life, and its manufacturing method.

The present invention is a control valve type lead-acid battery comprising a negative electrode plate and a positive electrode plate each containing an active material, a mat separator interposed between the negative electrode plate and the positive electrode plate, and an electrolyte solution,
The present invention relates to a control valve type lead-acid battery characterized in that the electrolytic solution is contained in an amount of 100.0 to 106.5% by volume with respect to the total pore volume of the negative electrode plate, the positive electrode plate and the mat separator.

The present invention also includes an electrode group in which a negative electrode plate and a positive electrode plate each containing an active material are alternately laminated via a mat separator in a battery case, and then an electrolyte is injected into the battery case. A control valve type lead-acid battery manufacturing method for chemical conversion comprising:
The electrolytic solution is injected in such an amount that the content after the formation of the battery case is 100.0 to 106.5% by volume with respect to the total pore volume of the negative electrode plate, the positive electrode plate and the separator. It relates to the manufacturing method of the control valve type lead acid battery.

  The control valve type lead storage battery of the present invention can sufficiently prevent a decrease in discharge capacity due to repeated charge and discharge, and improve cycle life.

1 is a schematic cross-sectional configuration diagram showing one embodiment of a control valve type lead storage battery according to the present invention.

  A control valve type lead storage battery (hereinafter sometimes simply referred to as “lead storage battery”) according to the present invention includes at least a negative electrode plate, a positive electrode plate, a mat separator interposed between the positive electrode plate and the negative electrode plate, and an electrolyte solution. For example, it has a structure as shown in FIG. FIG. 1 is a schematic sectional view showing an embodiment of a control valve type lead-acid battery according to the present invention, and shows a sectional view taken along a plane parallel to a side surface perpendicular to an electrode plate. In FIG. 1, 1 is a negative electrode plate, 2 is a positive electrode plate, 3 is a mat separator, and 4 is an electrode plate group produced by alternately laminating a plurality of negative electrode plates 1 and a plurality of positive electrode plates 2 with a mat separator 3 interposed therebetween. The electrolyte solution is absorbed and held in the negative electrode plate 1, the positive electrode plate 2, and the mat separator 3 by the respective capillary forces. The electrode plate group 4 is formed by alternately stacking six negative plates 1, five positive plates 2, and a mat separator 3, but at least one negative plate 1 and at least one positive plate 2. As long as they are laminated via the mat separator 3, the number thereof is not particularly limited. The mat separator 3 has a function of sucking up and holding the released excess electrolyte solution upward by capillary force.

  In the lead storage battery of the present invention, the electrolytic solution is contained in an amount of 100.0 to 106.5% by volume with respect to the total pore volume of the negative electrode plate 1, the positive electrode plate 2 and the mat separator 3. Thereby, while ensuring sufficient contact between the active material provided on the negative electrode plate 1 and the positive electrode plate 2 and the electrolytic solution, the corrosion of the strap 9 caused by the electrolytic solution sucked up by the mat separator 3 and the specific gravity of the electrolytic solution are reduced. So-called stratification, which differs between the upper and lower sides, is prevented. For this reason, a decrease in discharge capacity due to repeated charge and discharge is sufficiently prevented, and the cycle life is improved. If the electrolyte is too small relative to the total pore volume, the amount of the electrolyte in contact with the active material provided on the negative electrode plate 1 and the positive electrode plate 2 is small, so that the capacity is reduced and the cycle life is shortened. Become. On the other hand, if the electrolyte is too much relative to the total pore volume, sulfuric acid in the separator rises and the later-described strap 9 is likely to be corroded, or so-called stratification with different electrolyte specific gravity tends to be promoted. The cycle life is shortened.

  In a preferred embodiment, the electrolytic solution is preferably 100.5 to 106.5% by volume, more preferably 101.4 to 106.5% by volume with respect to the total pore volume described above from the viewpoint of improving cycle life. %, More preferably from 103.0 to 105.9% by volume, most preferably from 104.0 to 105.9% by volume.

  The content of the electrolytic solution only needs to be achieved after the formation of the battery case of the lead storage battery, that is, it can be obtained from the finished product. In particular, the total pore volume for expressing the content of the electrolytic solution is the total pore volume of the negative electrode plate 1, the positive electrode plate 2, and the mat separator 3 in the lead storage battery.

Specifically, the content (% by volume) of the electrolytic solution is determined based on the volume (x) of the electrolytic solution measured by decomposition of the lead acid battery (finished product) and the void volume of the negative electrode plate 1, the positive electrode plate 2, and the separator 3 (respectively y1, y2 and y3) can be determined based on the following equations.
Amount of electrolytic solution (volume%) = {x / (y1 + y2 + y3)} × 100

  x is the volume (ml) of the electrolyte. The lead acid battery is disassembled, the electrolyte solution is discarded, and the weight of the electrolyte solution is obtained from the difference between the total weight (dry weight) after washing and the total weight before decomposition, and the electrolyte solution weight is determined from the weight and the specific gravity of the electrolyte solution. Obtain the total volume x.

  y1 and y2 are pore volumes (ml) of the negative electrode plate 1 and the positive electrode plate 2, respectively, and are the total volume of the pores of each electrode plate. The pore volume of the negative electrode plate 1 and the positive electrode plate 2 is generally measured using a mercury intrusion method (JIS K1150). The mercury intrusion method is a method that pressurizes mercury into the pores of a solid sample and measures the pore size distribution of the solid sample. When the pressure applied to the mercury is gradually increased, Since mercury invades in order from small to small pores, the pore size distribution can be determined from the relationship between the applied pressure and the volume of mercury. Then, the pore volumes y1 and y2 of the positive electrode plate and the negative electrode plate are calculated from the pore size distribution of the positive electrode plate and the negative electrode plate.

y3 is the pore volume (ml) of the mat separator 3 in the lead acid battery. As will be described later, the mat separator 3 usually has a larger dimension than both the negative electrode plate 1 and the positive electrode plate 2, and therefore, a compression part that receives compression between the negative electrode plate 1 and the positive electrode plate 2 in the lead storage battery, And an uncompressed portion that is not subjected to the compression. Therefore, y3 is the sum of the pore volume y3a (ml) of the compression part and the void volume y3b (ml) of the non-compression part in the mat separator 3. The pore volumes y3a and y3b of the mat separator 3 are also measured by the mercury intrusion method described above. Specifically, the electrode plate group 4 is taken out from the battery case 5, and the interelectrode distance between the negative electrode plate 1 and the positive electrode plate 2 is measured. Then, after the separator 3 is removed from the electrode plate group 4 and the compression of the compression part is sufficiently released, the thickness of the separator 3 is measured, and the void volume y is measured by a mercury intrusion method. The pore volume y3b of the non-compressed portion is calculated from the measured pore volume y (the pore volume when the entire separator is in an uncompressed state) and the area ratio of the non-compressed portion to the entire separator 3. Thereafter, the compression ratio of the separator 3 compression part in the lead storage battery is calculated from the thickness of the separator 3 and the distance between the electrodes, and from the compression ratio, the measured void volume y, and the area ratio of the compression part to the whole separator 3 The void volume y3a of the compression part is calculated. For example, when the pore volume y of the removed separator 3 is 1300 ml, the compression ratio is 50%, and the area ratio of the compression part is 70%, the pore volume y3a of the compression part and the non-compression The void volume y3b of the part is 455 ml and 390 ml, respectively, and the void volume y3 of the separator 3 stored in the battery case 5 is 845 ml.
y3a = 1300 × 0.5 × 0.7 = 455ml
y3b = 1300 × 0.3 = 390ml
y3 = y3a + y3b = 845ml

  The above range of the content (volume%) of the electrolytic solution defined in the present invention is held by absorbing most or all of the electrolytic solution in the holes of the negative electrode plate 1, the positive electrode plate 2, and the separator 3 in the lead storage battery. This means that there is very little free electrolyte, if any. That is, in the lead storage battery of the present invention, it is difficult to observe the liquid level even if there is no free electrolyte (when 100% by volume) or it is present. This is because the free electrolyte is held by swelling in the non-compressed portion of the mat separator 3. The active material of the negative electrode plate and the positive electrode plate and the electrolyte solution held in the compression part of the separator are held in the pores by the capillary force of each component. In addition, the sulfuric acid and water discharged from the electrode plate active material in the charge / discharge process are designed to be held by the capillary force of the separator 3 and not fall to the lower part of the battery case. Even if the electrolytic solution temporarily accumulates in the lower part of the battery case 5, a force that rises upward by the capillary force works.

  Each member in the lead acid battery of this invention is demonstrated easily.

  The negative electrode plate 1 is a so-called paste-type electrode plate, and includes a negative electrode lattice body and a negative electrode active material filled in the negative electrode lattice body. As the negative electrode active material, spongy lead is the main component.

  The paste type negative electrode plate can be obtained by filling the negative electrode grid with paste for the negative electrode active material, aging and drying, and the negative electrode active material is produced in the negative electrode plate by the formation of the battery case in the lead acid battery manufacturing method To do. The negative electrode lattice body may be, for example, a cast lattice made of a lead alloy, or an expanded lattice formed by slitting a lead alloy sheet to provide a mesh shape, or A punching lattice formed by punching a lead alloy sheet to give a mesh shape may be used. Moreover, it is preferable to use a Pb alloy, especially a Pb—Ca alloy for the negative electrode lattice. The paste for the negative electrode active material can be usually obtained by adding an additive, water and sulfuric acid to lead powder and kneading.

The pore volume of the negative electrode plate 1, particularly the negative electrode active material, is preferably 0.171 to 0.217 ml / cm ³ , more preferably 0.180 to 0.209 ml / cm ³ .

  The positive electrode plate 2 is a so-called paste-type electrode plate, and includes a positive electrode lattice body and a positive electrode active material filled in the positive electrode lattice body. The positive electrode active material is mainly composed of porous lead dioxide.

  The paste type positive electrode plate can be obtained by filling the positive electrode grid with the paste for the positive electrode active material, aging and drying, and the positive electrode active material is generated in the positive electrode plate by the formation of the battery case in the lead acid battery manufacturing method. To do. As the positive electrode lattice body, any of the lattices similar to the negative electrode lattice body described above is used, and it is preferable to use a Pb alloy. The paste for the positive electrode active material can be usually obtained by adding an additive, water and sulfuric acid to lead powder and kneading.

The pore volume of the positive electrode plate 2, particularly the positive electrode active material, is preferably 0.140 to 0.186 ml / cm ³ , more preferably 0.149 to 0.178 ml / cm ³ .

  The number of the positive electrode plates 2 is usually the same as the number of the negative electrode plates 1, or one more than the number of the negative electrode plates 1, or less than one. In the present embodiment, the number of the negative electrode plate 1 is one more than that of the positive electrode plate 2. Therefore, the negative electrode plate 1 is a side surface portion of the battery case 5 at both ends in the stacking direction of the negative electrode plate and the positive electrode plate. Are arranged opposite to each other.

As the mat separator 3, a mat having a form such as a nonwoven fabric or a woven or knitted fabric capable of holding an electrolytic solution while preventing direct contact between the negative electrode plate 1 and the positive electrode plate 2 is used. Preferably, a mat having a form such as a nonwoven fabric or a woven or knitted fabric containing glass fibers, particularly fine glass fibers, is used, and examples thereof include AGM. The pore volume of the mat separator 3 is preferably 5.120 to 7.610 ml / cm ³ , more preferably 5.730 to 7.240 ml / cm ³ in a state corresponding to compression at 19.6 KPa / dm ² load based on SBA S 0406. is there.

  The mat separator 3 has a size larger than both the negative electrode plate 1 and the positive electrode plate 2 from the viewpoint of preventing direct contact between the negative electrode plate 1 and the positive electrode plate 2. For this reason, the mat separator 3 has a compression part which receives compression between the negative electrode plate 1 and the positive electrode plate 2, and a non-compression part which does not receive the said compression in a lead acid battery. For example, the mat separator 3 protrudes from both ends of the negative electrode plate and the positive electrode plate. Specifically, when the inside of the battery case is seen through from the direction perpendicular to the electrode plate, the mat separator 3 protrudes from the electrode plate at both ends in the width direction of the negative electrode plate and the positive electrode plate, Form. In the same case, the mat separator 3 protrudes from the electrode plate at the upper and lower portions in the height direction of the negative electrode plate and the positive electrode plate, and forms an uncompressed portion.

  The mat separator 3 is arranged so as to sandwich the positive electrode plate 2 in a U shape in FIG. 1, but the arrangement is not particularly limited as long as the mat separator is interposed between the negative electrode plate and the positive electrode plate. For example, the separator 3 may be disposed so as to sandwich the negative electrode plate in a U shape, or the separator 3 may be interposed between the negative electrode plate and the positive electrode plate without sandwiching the negative electrode plate or the positive electrode plate. It may be arranged independently. In addition, by sandwiching the positive electrode plate 2 not facing the battery case 5 with the separator 3, the electrode plate group 4 is placed in the battery case 5 as compared with the case where the negative electrode plate 1 facing the battery case 5 is sandwiched between the separators 3. It can suppress that the separator 3 contacts the battery case 5 at the time of insertion, and is damaged, and can suppress the fall of the cycle life by a short circuit. Moreover, the number of the separators 3 can be reduced by reducing the number of the separators 3 to the positive electrode plate 2 which is a small number of sheets, and the cost of the lead storage battery can be reduced.

  Diluted sulfuric acid is used as the electrolyte. The specific gravity of the electrolytic solution is not particularly limited as long as the specific gravity is conventionally set in the field of control valve type lead storage batteries.

  The lead storage battery of the present invention usually further includes a battery case 5 for accommodating the electrode plate group 4, an inner lid 6 for sealing the battery case 5 after the electrode plate group 4 is accommodated, and the inner lid 6. After the tank 5 is sealed, the inlet 8 for injecting the electrolytic solution into the inside 7 of the battery case 5, and the plurality of negative plates 1 and the plurality of positive plates 2 constituting the electrode group 4 are connected in common. And a control valve 10 for controlling the pressure in the inside 7 of the battery case 5, and an upper lid 11 for covering the control valve 10.

The lead acid battery of this invention can be manufactured with the following method.
First, at least one negative electrode plate 1 and at least one positive electrode plate 2 are alternately stacked via a mat separator 3 to form an electrode plate group 4. Next, the electrode plate group 4 is pressurized to, for example, a pressure of about 40 kPa and accommodated in the battery case 5.

  After the electrode plate group 4 is housed in the battery case 5, the battery case 5 is sealed with the inner lid 6, and an electrolytic solution is injected from the inlet 8 provided in the inner lid 6 to form a battery case. The amount of injection (volume) of the electrolytic solution is an amount such that the content (volume%) of the electrolytic solution defined in the present invention falls within the above-described range after the formation of the battery case. Battery case formation is a treatment in which a direct current is passed between a positive electrode plate and a negative electrode plate in a dilute sulfuric acid electrolyte to oxidize and reduce, and lead is produced in the negative electrode plate and lead dioxide is produced in the positive electrode plate. After the formation of the battery case, the control valve 10 may be attached to the inlet 8 and the upper lid 11 may be attached to the upper end of the inner lid 6. In addition, if content (volume%) of electrolyte solution is in the above-mentioned range after battery case formation, a chemical conversion method will not be specifically limited, Tank formation may be sufficient not only in battery case formation.

[Example 1]
The control valve type lead acid battery shown in FIG. 1 was manufactured. The valve-regulated lead-acid battery had a shape and dimensions in accordance with DIN EN 50342-2 standards. Specifically, it was produced according to the following method.

A grid was obtained by casting using a lead alloy composed of a Pb—Ca alloy, and used as a negative electrode grid and a positive grid.
Additives were added to the lead powder, and dilute sulfuric acid was added thereto and kneaded to prepare a positive electrode active material paste. The positive electrode active material paste was filled in the positive electrode lattice body and aged and dried, thereby obtaining an unformed positive electrode plate.
An additive was added to the lead powder, and dilute sulfuric acid was added thereto and kneaded to prepare a negative electrode active material paste. The negative electrode active material was filled with a negative electrode active material paste and aged and dried to obtain an unformed negative electrode plate.
An ultrafine glass mat (AGM) was used as a separator.
As the electrolytic solution, dilute sulfuric acid having a specific gravity of 1.215 (20 ° C.) was used.

Pressure capable of uniformly contacting the electrode plate group 4 produced by alternately stacking the six negative electrode plates 1 and the five positive electrode plates 2 sandwiched between the separators 3 (in this embodiment, about 40 kPa) And pressurized and stored in the battery case 5. Thereafter, the battery case 5 was sealed with the inner lid 6, and a predetermined amount of electrolyte was injected from the inlet 8 provided in the inner lid 6. Next, after forming the battery case, the control valve 10 was attached to the injection port 8, and the upper lid 11 was attached to the upper end of the inner lid 6.
When the content (% by volume) of the electrolytic solution was determined by the above-described method, it was 101.4% by volume with respect to the total pore volume of the negative electrode plate, the positive electrode plate, and the separator.
The pore volume of the negative electrode plate was 0.182 ml / cm ³ .
The hole volume of the positive electrode plate was 0.160 ml / cm ³ .
The pore volume of the separator was 6.500 ml / cm ³ when loaded with 19.6 KPa / dm ² .

[Examples 2-6 and Comparative Examples 1-3]
Similar to Example 1 except that the electrolyte solution shown in Table 1 adjusted to a predetermined specific gravity by adjusting the sulfuric acid concentration was used, and that the injection amount of the electrolyte solution was adjusted to the values shown in Table 1. A control valve type lead acid battery was manufactured by the method described above.
The specific gravity of the electrolytic solution was adjusted in order to make the amount of sulfate radicals in the electrolytic solution actually used constant.

[Evaluation]
Six batteries obtained in each example / comparative example were connected in series, and the following charge / discharge cycle test was performed.
First, the state of charge (SOC) was adjusted to 50%, that is, the charged state of 50% with respect to the rated capacity (12V). Next, in a 40 ° C. environment, “discharge-charge” was repeated a predetermined number of times under the following conditions. The number of cycles when the voltage after discharge (discharge end voltage) became 10.0 V or less was recorded as the number of life cycles.
Discharge: 17.5A constant current discharge for 2 hours;
Charging: Constant voltage charging of 14.4V for 2 hours at a maximum current of 17.5A.

The greater the number of life cycles (N), the better. Evaluation was performed according to the following rank.
；; 375 ≦ N; most preferred range;
O; 350 ≦ N <375; preferred range;
Δ: 300 ≦ N <350; practically no problem range;
X: N <300; practically problematic range.

  1: negative electrode plate, 2: positive electrode plate, 3: mat separator, 4: electrode plate group, 5: battery case, 6: inner lid, 7: inside, 8: inlet, 9: strap, 10: control valve, 11 : Upper lid.

Claims (5)

A negative electrode plate and a positive electrode plate each containing an active material, a mat separator interposed between the negative electrode plate and the positive electrode plate, and a control valve type lead storage battery comprising an electrolyte solution,
A control valve type lead acid battery, wherein the electrolytic solution is contained in an amount of 100.0 to 106.5% by volume with respect to the total pore volume of the negative electrode plate, the positive electrode plate and the mat separator.   The control valve type lead-acid battery according to claim 1, wherein the content of the electrolytic solution is 101.4 to 106.5% by volume with respect to the total pore volume of the negative electrode plate, the positive electrode plate, and the mat separator. The negative electrode plate has a pore volume of 0.180 to 0.209 ml / cm ³ ;
The positive electrode plate has a pore volume of 0.149 to 0.178 ml / cm ³ ;
The control valve type lead-acid battery according to claim 1 or 2, wherein the mat separator has a pore volume of 5.730 to 7.240 ml / cm ³ at 19.6 KPa / dm ² load. A plurality of negative plates and positive plates, respectively,
The control valve type lead acid battery according to any one of claims 1 to 3, wherein an electrode plate group in which a negative electrode plate and a positive electrode plate are alternately laminated via the mat separator is housed in a battery case. A control valve type in which a negative electrode plate and a positive electrode plate each containing an active material are alternately stacked via a mat separator, and an electrode group is stored in a battery case, and then an electrolyte is injected to form a battery case. A method of manufacturing a lead-acid battery,
Injecting the electrolytic solution in an amount such that the content after the formation of the battery case is 100.0 to 106.5% by volume with respect to the total pore volume of the negative electrode plate, the positive electrode plate and the mat separator. A control valve type lead-acid battery manufacturing method.

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