JP6551012B2 - Negative electrode for lead acid battery and lead acid battery - Google Patents

Description

  The present invention relates to a lead storage battery, and more particularly to a negative electrode for a lead storage battery mounted on a vehicle having an idling stop system.

  Lead-acid batteries are used in various applications in addition to cell starters for automobiles because lead-acid batteries are inexpensive, have relatively high battery voltage, and can obtain high power. The lead acid battery includes a positive electrode containing lead dioxide as a positive electrode active material, a negative electrode containing lead as a negative electrode active material, a separator interposed between the positive electrode and the negative electrode, and an electrolyte containing an aqueous sulfuric acid solution. The positive electrode and the negative electrode include a grid-like current collector for attaching an active material.

  As the deterioration of the lead storage battery proceeds, the conductivity of the negative electrode decreases and the charge acceptance of the negative electrode tends to decrease. On the other hand, from the viewpoint of improving the conductivity of the negative electrode, unevenness is provided on the surface of the current collector to improve the adhesion between the negative electrode active material and the current collector (see Patent Documents 1 and 2). It has been proposed to add carbon black (see Patent Document 3).

Japanese Patent Application Laid-Open No. 56-86468 JP-A-8-96811 JP 2003-338285 A

  In recent years, idling-stop system (ISS) equipped vehicles have been spreading as environmentally friendly vehicles. Since lead storage batteries used in ISS-equipped vehicles are frequently exposed to an engine stop state, the state of charge (SOC) is often used in an intermediate charge state of about 90 to 70%. In this respect, the lead storage battery used in an ISS-equipped vehicle is required to have a performance different from that of a conventional start-up lead storage battery that is always used in a fully charged state.

  If the battery continues to be used in the mid-charge state, sulfation of the negative electrode active material proceeds, and the conductivity of the negative electrode decreases. The present inventors have elucidated that this sulfation proceeds from the three-phase interface where the current collector (grid body) in the negative electrode, the active material and the electrolyte exist.

  In view of the above, one aspect of the present invention includes a negative electrode mixture and a negative electrode grid having a surface supporting the negative electrode mixture, the negative electrode mixture including a negative electrode active material containing lead, and carbon black And the amount of the carbon black contained in the negative electrode mixture is 0.05 parts by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the negative electrode active material, and at least the surface of the negative electrode grid A part of the surface roughness Rz relates to a negative electrode for a lead storage battery, which is 70 μm or more. Here, the surface roughness Rz means a ten-point average roughness in JIS B 0601-1994.

  Another aspect of the present invention relates to a lead-acid battery including the negative electrode for a lead-acid battery, a positive electrode, a separator interposed between the negative electrode and the positive electrode, and an electrolytic solution containing an aqueous sulfuric acid solution.

  According to the present invention, since sulfation of the negative electrode is suppressed, the life characteristics of the lead storage battery are improved when the lead storage battery is used in an ISS-equipped vehicle.

It is the perspective view which notched some lead acid batteries concerning one embodiment of the present invention. It is a front view of the positive electrode plate in the lead storage battery of FIG. It is a front view of the negative electrode plate in the lead storage battery of FIG.

  The negative electrode for a lead storage battery according to the present invention includes a negative electrode mixture and a negative electrode grid having a surface supporting the negative electrode mixture, and the negative electrode mixture includes a negative electrode active material containing lead and carbon black. However, the amount of carbon black contained in the negative electrode mixture is 0.05 parts by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the negative electrode active material, and at least one of the surfaces supporting the negative electrode mixture of the negative electrode grid. The surface roughness Rz of the part (hereinafter also referred to as Rz of the mixture-supporting surface) is 70 μm or more. The negative electrode active material contains a predetermined amount of carbon black, and the Rz on the surface of the mixture support is set to 70 μm or more, thereby reducing the reaction resistance at the three-phase interface, suppressing the progress of sulfation at the three-phase interface, The characteristics are remarkably improved.

  The surface of the negative electrode grid carrying the negative electrode mixture is roughened to a certain level or more, and the carbon black is dispersed in the negative electrode mixture in a necessary and sufficient amount, so that the carbon black has minute irregularities or pits on the negative electrode grid. It is thought that the anchor effect is developed. Thereby, it is considered that the contact area of carbon black at the negative electrode lattice interface is greatly increased, and the reaction resistance in the mid-charge state is significantly reduced.

  From the viewpoint of improving the conductivity of the negative electrode, it is considered that the larger the amount of carbon black dispersed in the negative electrode mixture, the more desirable. However, when Rz of the mixture-supporting surface is 70 μm or more, the amount of carbon black is 2 parts by mass or less with respect to 100 parts by mass of the negative electrode active material. When the amount of carbon black exceeds 2 parts by mass with respect to 100 parts by mass of the negative electrode active material, the improvement width of the life characteristics is rather reduced. In addition, the hydrogen generation overvoltage of the negative electrode is lowered, and the decomposition of the electrolytic solution tends to be promoted.

  From the viewpoint of sufficiently enhancing the anchor effect of carbon black, the amount of carbon black is desirably 0.05 parts by mass or more and more preferably 0.1 parts by mass or more with respect to 100 parts by mass of the negative electrode active material. Desirably, the amount is more preferably 0.3 parts by mass or more. In addition, from the viewpoint of increasing the width of improvement of the life characteristics, the amount is preferably 1 part by mass or less, more preferably 0.9 parts by mass or less, and still more preferably 0.5 parts by mass or less. From the above, the particularly preferable range of the amount of carbon black contained in the negative electrode mixture is, for example, 0.1 part by mass to 0.9 part by mass or 0.1 part by mass to 0.5 part by mass with respect to 100 parts by mass of the negative electrode active material. It is a department.

  Rz on the mixture carrying surface may be 70 μm or more, but is preferably 80 μm or more, more preferably 100 μm or more, and further preferably 150 μm or more. However, if the surface roughness becomes too large, the mechanical strength of the negative electrode grid may be lowered. Therefore, the Rz of the mixture-supporting surface is desirably 300 μm or less, and more preferably 200 μm or less. From the above, the particularly preferable range of Rz of the mixture-supporting surface is, for example, 70 μm to 300 μm or 80 μm to 200 μm.

  The negative electrode grid may be roughened such that the surface roughness Rz of at least a part of the surface supporting the negative electrode mixture is 70 μm or more. For example, a region that can be immersed in an electrolytic solution having a high sulfuric acid concentration may be selectively roughened. As the concentration of sulfuric acid in the electrolytic solution increases with distance from the liquid surface and sulfation easily proceeds, only the region located far from the liquid surface of the negative electrode grid may be selectively roughened. However, even when roughening only a part of the surface supporting the negative electrode mixture, the surface roughness Rz of 30% or more, and further 50% or more of the surface supporting the negative electrode mixture may be 70 μm or more. preferable.

  If the negative electrode grid has an exposed portion not having a negative electrode mixture and the exposed portion has an ear for connecting to the negative electrode shelf, only the area far from the ear may be roughened. Specifically, when the surface carrying the negative electrode mixture of the negative electrode grid is divided into a first region closer to the ear and a second region other than that, the average value of the surface roughness Rz in the first region (Rz 1 ) May be smaller than the average value (Rz2) of the surface roughness Rz in the second region. At this time, the boundary between the first region and the second region may be set to be parallel to the liquid level in the lead storage battery. Further, the boundary may be set so that the negative electrode mixture amount carried in the first region is the same as the negative electrode mixture amount carried in the second region.

The average value Rz1 of the surface roughness is expressed by, for example, the following formula (1) when dividing the first region into n equal area regions each having a surface roughness R1 (i) (i is an integer from 1 to n). It is represented by). Similarly, the average value Rz2 of the surface roughness is, for example, when the second region is divided into n equal area regions each having the surface roughness R2 (i) (i is an integer from 1 to n). It is expressed by equation (2). ΣR1 (i) is the sum of the surface roughness of the n regions constituting the first region, and ΣR2 (i) is the sum of the surface roughness of the n regions constituting the second region. When calculating the average values Rz1 and Rz2, n is preferably 3 or more. Also, R1 (i) and R2 (i) may be measured near the center of each of the divided regions.
Rz1 = (ΣR1 (i)) / n (1)
Rz2 = (ΣR2 (i)) / n (2)

  From the viewpoint of suppressing local deterioration of the negative electrode and maintaining the reactivity of the entire negative electrode as uniformly as possible, Rz2 / Rz1 is preferably 1.4 or more, and more preferably 1.6 or more.

  The form of the negative electrode grid is not particularly limited, and a cast grid may be used. However, it is preferable to use an expanded lattice obtained by expanding a lead alloy sheet in terms of excellent productivity. The processing method is not particularly limited, and a rotary expand processing may be adopted, or a reciprocal expand processing may be adopted.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a partially cutaway perspective view of a lead-acid battery according to an embodiment of the present invention. The lead storage battery 1 includes an electrode plate group 11 and an electrolyte (not shown), which are accommodated in a battery case 12. The battery case 12 is divided into a plurality of cell chambers 14 by a partition wall 13, and each cell chamber 14 stores one electrode plate group 11 and also stores an electrolytic solution. The electrode plate group 11 is configured by laminating a plurality of positive electrodes 2 and negative electrodes 3 via a separator 4.

  In the cell chamber 14 located at one end of the battery case 12, the positive electrode shelf 6 that connects the ears 22 of the plurality of positive electrodes 2 in parallel is connected to the positive electrode connector 8. On the other hand, the negative electrode post 7 is connected to the negative electrode shelf 5 in which the ears 32 of the plurality of negative electrodes 3 are connected in parallel. In the cell chamber 14 located at the other end of the battery case 12, the positive electrode post is connected to the positive electrode shelf 6, and the negative electrode connector is connected to the negative electrode shelf 5. The positive electrode connector 8 is connected to the negative electrode connector continuously connected to the negative electrode shelf 5 of the electrode plate group 11 in the adjacent cell chamber 14 via the through hole provided in the partition wall 13. Thereby, the electrode plate groups 11 in the adjacent cell chambers 14 are connected in series.

  In each cell chamber 14, the whole of the positive electrode shelf 6, the negative electrode shelf 5, and the electrode plate group 11 is immersed in the electrolytic solution. A lid 15 provided with a positive electrode terminal 16 and a negative electrode terminal 17 is attached to the opening of the battery case 12. An exhaust plug 18 for discharging the gas generated inside the battery to the outside of the battery is attached to the liquid injection port provided in the lid 15.

(Positive electrode)
FIG. 2 is a front view of the positive electrode 2. The positive electrode 2 includes a positive electrode grid 21 and a positive electrode mixture 24 supported on the positive electrode grid 21. The positive electrode grid 21 is an expanded grid including an expanded mesh 25 holding the positive electrode mixture 24, a frame 23 provided at the upper end of the expanded mesh 25, and an ear 22 connected to the frame 23. The positive electrode 2 is connected to the positive electrode shelf 6 via the ear 22, and the positive electrode shelf 6 is connected to the positive electrode connector 8 or the positive electrode column.

  The positive electrode grid 21 is obtained by expanding a lead alloy sheet in the same manner as the negative electrode grid 31 described later. It is preferable that the lead alloy constituting the positive electrode grid 21 contains calcium (Ca) and tin (Sn). The calcium content in the lead alloy is, for example, 0.01 to 0.1% by mass. The tin content in the lead alloy is, for example, 0.05 to 3% by mass. Calcium mainly improves the mechanical strength of the lead alloy, and tin mainly improves the corrosion resistance of the lead alloy. The lead alloy sheet may have a plurality of lead alloy layers different in composition.

Lead oxide (PbO ₂ ) is used as the positive electrode active material. The positive electrode mixture may contain known additives, as required, in addition to the positive electrode active material.

  The positive electrode 2 is produced by filling or applying a paste containing a positive electrode mixture and a dispersion medium to a positive electrode lattice and further performing a chemical conversion treatment. As a dispersion medium of the paste, sulfuric acid and / or water can be used.

(Negative electrode)
FIG. 3 is a front view of the negative electrode 3. The negative electrode 3 includes a negative electrode grid 31 and a negative electrode mixture 34 supported on the negative electrode grid 31. The negative electrode grid 31 is an expanded grid including an expanded mesh 35, a frame 33 provided at the upper end of the expanded mesh 35, and an ear 32 connected to the frame 33. The negative electrode 3 is connected to the negative electrode shelf 5 via the ear 32, and the negative electrode shelf 5 is connected to the negative electrode column 7 or the negative electrode connector. The negative electrode mixture 34 is supported on the expanded mesh 35. The frame 33 and the ear 32 are exposed portions of the negative electrode grid.

  The negative electrode grid 31 is obtained by expanding a lead alloy sheet. The lead alloy sheet is obtained, for example, by rolling a lead alloy slab obtained by continuous slab casting of a molten lead alloy.

  The lead alloy slab is manufactured, for example, by supplying a molten lead alloy to a wheel-type rotary mold and quenching the molten metal between a steel belt that rotates and moves together with the mold. The thickness of the lead alloy slab is, for example, about 5 to 20 mm. The lead alloy slab is subsequently rolled by multistage rolling and recovered as a lead alloy sheet. The thickness of the lead alloy sheet is, for example, about 0.5 mm to 1.5 mm.

  Next, the lead alloy sheet is expanded to form a negative electrode grid (expanded grid). In the expansion process, a large number of slits parallel to each other are formed in a zigzag in the lead alloy sheet, and then the cut is expanded. Thereby, a lead alloy sheet is processed into a mesh shape.

  Next, roughening is performed on the surface of the region carrying the negative electrode mixture (that is, the expanded mesh 35) in the negative electrode lattice. In general, an expanded grid is manufactured by processing a lead alloy sheet subjected to multiple rolling, so that the surface is smooth. Therefore, the surface of the expanded mesh 35 is positively roughened before or after the expanding process.

  The surface roughening method is not particularly limited. For example, a blast method, a roll brushing method, a plating method, an etching method, and the like can be given. Among these, the blast method and the roll brushing method are preferable because they can be implemented at low cost and are excellent in productivity. The blast method is a method of blasting a powdery abrasive onto the expanded network at a high speed to abrade the surface of the expanded network by roughening. The roll brushing method is a method in which a rotating wire brush is pressed into an expanded mesh to form a streak groove on the surface of the skeleton to roughen the surface.

  The expanded mesh 35 only needs to be roughened so that at least a part of the surface roughness Rz is 70 μm or more. That is, the surface roughening may be performed on the surface of the entire skeleton of the expanded network 35, or may be selectively performed on a part of the surface of the skeleton. Thereby, the effort of roughening can be abbreviate | omitted and manufacturing cost can be reduced.

  From the viewpoint of uniformly maintaining the reactivity of the entire negative electrode, it is preferable to selectively perform roughening only in a region where contact with an electrolyte having a high sulfuric acid concentration is expected. For example, as shown in FIG. 3, the surface of the expanded mesh 35 of the substantially rectangular negative electrode lattice (that is, the surface carrying the negative electrode mixture) is divided into a first region R1 near the ear and a second region R2 other than that. When dividing, the average value Rz1 of the surface roughness Rz in the first region R1 may be smaller than the average value Rz2 of the surface roughness Rz in the second region R2.

  In FIG. 3, the broken line L2 indicates the end portion of the first region R1 closest to the ear 32, and the broken line L3 indicates the boundary between the first region R1 and the second region R2. The broken line L1 has shown the liquid level of the electrolyte solution in the completed lead acid battery. The broken line L3 is parallel to the broken line L1.

  As shown in FIG. 3, only a partial region 2A (the hatched region in FIG. 3) farthest from the ear 32 of the second region R2 may be roughened. At this time, the average value Rz1 of the surface roughness Rz in the first region R1 is inevitably smaller than the average value Rz2 of the surface roughness Rz in the second region R2.

  The lead alloy constituting the negative electrode grid 31 preferably contains calcium (Ca) and tin (Sn). The calcium content in the lead alloy is, for example, 0.01 to 0.1% by mass. The tin content in the lead alloy is, for example, 0.1 to 2.0% by mass. Calcium mainly improves the mechanical strength of lead alloys, and tin improves corrosion resistance. The lead alloy sheet may have a plurality of lead alloy layers different in composition.

  Lead is used as the negative electrode active material. Lead may contain a trace amount of alloy components. At this time, the negative electrode mixture contains 0.05 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, with respect to 100 parts by mass of lead. However, the amount of carbon black is preferably 1 part by mass or less, more preferably 0.9 parts by mass or less, and still more preferably 0.5 parts by mass or less with respect to 100 parts by mass of lead.

  When preparing the negative electrode mixture, powdered lead can be used as a raw material, and the raw material may contain lead oxide. The negative electrode mixture may contain, in addition to the negative electrode active material and carbon black, a shrinkproofing agent (such as lignin) and / or a binder (such as a polymer). The negative electrode mixture may optionally contain other known additives.

  Carbon black may be mixed only with a powdered negative electrode active material, or carbon black may be dispersed in a lead or lead alloy matrix by kneading carbon black into lead or a lead alloy as a negative electrode active material. .

  The average primary particle size of carbon black is desirably 10 nm to 100 nm. This is because the aggregate formed of such primary particles easily enters minute irregularities or pits of the negative electrode lattice having a surface roughness Rz of 70 μm or more. The type of carbon black is not particularly limited, and acetylene black, ketjen black, thermal black, oil furnace black, channel black and the like can be used.

  The negative electrode 3 is produced by filling or applying a paste containing a negative electrode mixture and a dispersion medium to a negative electrode lattice and further subjecting it to a chemical conversion treatment. As a dispersion medium for the paste, sulfuric acid and / or water can be used.

  The chemical conversion treatment is performed, for example, by charging the positive electrode 2 and the negative electrode 3 before formation in an electrolytic solution containing a sulfuric acid aqueous solution in a battery case of a lead storage battery.

(Separator)
Examples of the separator include a microporous membrane or a fiber sheet (or mat). As a polymer material which comprises a microporous film or a fiber sheet, what has acid resistance is preferable, and polyolefin, such as polyethylene and a polypropylene, etc. can be illustrated. The fiber sheet may be formed of inorganic fibers such as polymer fibers and / or glass fibers. The separator may contain an additive such as a filler and / or carbon as necessary.

(Electrolyte solution)
The electrolyte contains a sulfuric acid aqueous solution. The density of the electrolyte is, for example, 1.1~1.35g / cm ^3, is preferably 1.2~1.35g / cm ^3, to be 1.25~1.3g / cm ³ More preferable. In the present specification, the density of the electrolyte is the density at 20 ° C., and the density of the electrolyte in a fully charged battery is preferably in the above range.

Hereinafter, the present invention will be specifically described based on examples and comparative examples. However, the present invention is not limited to the following examples.
Example 1
(1) Production of positive electrode A positive electrode 2 as shown in FIG. 2 was produced by the following procedure.
By mixing raw material powder (mixture of lead and lead oxide), water and dilute sulfuric acid (density 1.40 g / cm ³ ) at a mass ratio of 100: 15: 5, a paste containing a positive electrode mixture is obtained. Obtained.

  A lead alloy positive grid was fabricated by continuous slab casting, multistage rolling and expanding. The lead alloy had a tin content of 1.6 mass% and a calcium content of 0.05 mass%.

  The expanding process was performed by a reciprocating method, and a plurality of parallel slits were formed in a staggered manner at predetermined locations of the lead alloy sheet, and the expanded mesh 25 was formed by expanding the slits, whereby a positive electrode lattice 21 was obtained. The lead alloy sheet was not subjected to the expansion process, and the ears 22 and the frame bones 23 of the positive electrode lattice 21 were formed.

  An expanded mesh 25 is filled with a paste containing a positive electrode mixture and aged and dried to obtain an unformed positive electrode 2 (vertical: 115 mm, horizontal: 137.5 mm) in which the positive electrode mixture 24 is held on the positive electrode grid 21. The

(2) Production of negative electrode A negative electrode 3 as shown in FIG. 3 was produced by the following procedure.
Raw material powder (lead), water, dilute sulfuric acid (density 1.40 g / cm ³ ), lignin, barium sulfate, and carbon black are in a mass ratio of 100: 12: 7: 1: 0.1: 0. By mixing at a ratio of 5, a paste containing a negative electrode mixture was obtained. The amount of carbon black was 0.5 parts by mass with respect to 100 parts by mass of the negative electrode active material. As the carbon black, oil furnace black having a primary particle diameter of 30 nm was used.

  A lead alloy negative electrode grid 31 having an ear 32, a frame 33, and an expanded mesh 35 was produced in the same manner as the positive electrode grid. The lead alloy had a tin content of 1.16% by mass and a calcium content of 0.05% by mass.

  Next, the entire expanded mesh 35 of the negative electrode grid 31 was roughened by roll brushing to adjust the surface roughness of the expanded mesh 35 to 80 μm. The surface roughness Rz of the expanded mesh 35 before roughening was 50 μm.

  The expanded mesh of the roughened negative electrode lattice 31 is filled with a paste containing a negative electrode mixture, and an unformed negative electrode 3 in which the negative electrode mixture 34 is supported on the negative electrode lattice 31 (length: 115 mm) by the same method as described above. , 137.5 mm wide).

(3) Preparation of Test Cell for Lead Acid Battery Two positive electrodes and one negative electrode prepared in the above (1) and (2) were cut into a size of 60 mm long and 40 mm wide, respectively, and one negative electrode was used as a separator ( An electrode plate group was formed by sandwiching two positive electrodes with a polyethylene microporous film having a thickness of 0.2 mm and a width of 44 mm. At this time, the negative electrode was disposed so as to be sandwiched between the separators 4 folded in half.

The obtained electrode plate group was sandwiched and fixed from both sides by an acrylic resin plate. Subsequently, a lead made of lead was welded to each of the negative electrode and the two positive electrodes to form a negative electrode terminal and a positive electrode terminal. Thereafter, the electrode plate group was placed in a container made of an acrylic resin, and a predetermined amount of a sulfuric acid aqueous solution having a specific gravity of 1.20 g / cm ³ was injected to perform formation.

The sulfuric acid aqueous solution in the cell used for chemical conversion was removed, and a sulfuric acid aqueous solution having a specific gravity of 1.28 g / cm ³ was newly injected until the positive electrode mixture and the negative electrode mixture were completely immersed. In this way, a test cell (1.25 Ah, 2 V) was produced.

[Evaluation]
(Life characteristics of batteries for vehicles equipped with ISS)
The SOC of the test cell after formation was adjusted under the following conditions.
Discharge: Constant current (0.2C), 30 minutes Rest: 1 hour Temperature: 25 ° C

Next, based on the idling stop life test (SBA S0101), the charge / discharge cycle was repeated under the following conditions for accelerating the deterioration of the negative electrode. Then, the number of cycles at which the voltage drops to 1.0 V was obtained as the number of life times by 60 seconds after the start of discharge.
Charge: constant current (2.2C) -constant voltage (2.4V, maximum current 2.2C), 0.03 hours Discharge: constant current (1.0C), 0.03 hours Temperature: 25 ° C.

(Reduction rate of electrolyte)
The test cell mass after the SOC adjustment and the test cell mass when the charge / discharge cycle reached the number of lifetimes were measured, and the amount of decrease in the electrolyte was calculated from the difference therebetween. Next, as a liquid reduction rate, the ratio of the amount of decrease with respect to the initial amount of electrolytic solution was obtained as a percentage.

Example 2
An example except that the entire expanded network 35 was roughened by blasting using alumina particles having an average particle diameter of 100 μm as an abrasive and that the surface roughness Rz of the expanded network 35 was adjusted to 100 μm. Test cells were prepared in the same manner as 1 and evaluated in the same manner.

Example 3
A test cell was prepared and evaluated in the same manner as in Example 2 except that the surface roughness Rz of the expanded mesh 35 was adjusted to 150 μm.

Example 4
A test cell was prepared and evaluated in the same manner as in Example 2 except that the surface roughness Rz of the expanded mesh 35 was adjusted to 200 μm.

Example 5
The expanded mesh 35 is divided into a first region R1 close to the ear and a second region R2 other than that, the entire surface roughness Rz of the second region R2 is adjusted to 200 μm, and the first region R1 is roughened A test cell was prepared and evaluated in the same manner as in Example 2 except that the preparation was not performed. The time required for roughening the expanded mesh and the amount of abrasive used were both about half those of Example 4.

Example 6
A test cell was produced and evaluated in the same manner as in Example 4 except that the amount of carbon black was 0.3 parts by mass with respect to 100 parts by mass of the negative electrode active material.

Example 7
A test cell was prepared and evaluated in the same manner as in Example 4 except that the amount of carbon black relative to 100 parts by mass of the negative electrode active material was 1 part by mass.

<< Example 8 >>
A test cell was prepared and evaluated in the same manner as in Example 1 except that the amount of carbon black relative to 100 parts by mass of the negative electrode active material was 0.1 parts by mass.

Comparative Example 1
A test cell was prepared and evaluated in the same manner as in Example 1 except that the expanded mesh 35 was not roughened and carbon black was not added to the negative electrode mixture.

Comparative Example 2
Test cells were produced in the same manner as in Example 1 except that the roughening of the expanded mesh 35 was not performed, and evaluations were made in the same manner.

Comparative Example 3
A test cell was prepared and evaluated in the same manner as in Example 4 except that carbon black was not added to the negative electrode mixture.

  The results are shown in Table 1. The life improvement rate indicates the percentage of the number of increase times with respect to the life number of Comparative Example 1 as a percentage.

ＣＢ量：負極活物質１００質量部に対するカーボンブラック量

CB amount: Carbon black amount relative to 100 parts by mass of the negative electrode active material

  Comparing Comparative Examples 1 and 2, it can be seen that the life is improved by about 11% even when carbon black is added to the negative electrode mixture without roughening the negative electrode lattice. Further, when Comparative Examples 1 and 3 are compared, it can be seen that the life is improved by about 10% when the negative electrode grid is sufficiently roughened without adding carbon black to the negative electrode mixture.

  On the other hand, in Example 1, although the degree of roughening was weaker than that of Comparative Example 3, the life improvement effect exceeding the added value of the effects obtained in Comparative Examples 2 and 3 was obtained. In addition, in Example 4 in which the negative electrode grid was sufficiently roughened as in Comparative Example 3, a remarkable synergistic effect can be confirmed.

  However, when the amount of carbon black is increased, although the liquid reduction rate is within the allowable range, the improvement width of the life tends to be reduced. Therefore, the amount of carbon black is desirably 1 part by mass or less, and particularly 0.5 part by mass or less, per 100 parts by mass of the negative electrode active material.

  The lead storage battery using the negative electrode for a lead storage battery according to the present invention is suitable as a power supply for a ISS vehicle because it can suppress a sulfation specific to the case of a ISS vehicle.

1: lead storage battery 2: positive electrode 3: negative electrode 4: separator 5: negative electrode shelf 6: 6: positive electrode shelf 7: negative electrode pole 8: positive electrode connector 11: electrode plate group 12: battery case 13 A partition wall 14: a cell chamber 15: a lid 16: a positive electrode terminal 17: a negative electrode terminal 18: an exhaust plug 21: a positive electrode grid 22: a positive electrode grid ear 23: a positive electrode grid frame 24: a positive electrode Mixture 25: Expanded network of positive electrode grid 31: Negative electrode grid 32: Ear of negative electrode grid 33: Frame of negative electrode grid 34: Negative electrode material mixture 35: Expanded network of negative electrode grid

Claims (6)

A negative electrode mixture, and a negative electrode lattice having a surface carrying the negative electrode mixture,
The negative electrode mixture includes a negative electrode active material containing lead, and carbon black,
The amount of the carbon black contained in the negative electrode mixture is 0.05 parts by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the negative electrode active material,
The negative electrode for lead-acid batteries, wherein the surface roughness Rz (ten-point average roughness) of at least a part of the surface of the negative electrode lattice is 70 μm or more.   The negative electrode for lead acid battery according to claim 1, wherein an amount of the carbon black contained in the negative electrode mixture is 0.1 parts by mass to 1 part by mass with respect to 100 parts by mass of the negative electrode active material. The negative electrode lattice has an exposed portion not having the negative electrode mixture,
The exposed portion has an ear for connecting to the negative electrode shelf,
When the surface carrying the negative electrode mixture is divided into the first region near the ear and the other second region, the average value Rz1 of the surface roughness Rz in the first region is the second region. The negative electrode for a lead acid battery according to claim 1, wherein the negative electrode is for a lead-acid battery that is smaller than an average value Rz2 of surface roughness Rz in the region.   The negative electrode for lead acid battery according to claim 3, wherein Rz2 / Rz1 is 1.6 or more.   The negative electrode for lead acid batteries according to claim 1, wherein the negative electrode lattice is an expanded lattice. The lead acid battery containing the negative electrode for lead acid batteries of Claim 1, a positive electrode, the separator interposed between the said negative electrode and the said positive electrode, and the electrolyte solution containing sulfuric acid aqueous solution.

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