CN112753119A

CN112753119A - Lead-acid battery

Info

Publication number: CN112753119A
Application number: CN201980062911.8A
Authority: CN
Inventors: 小嶋优作; 安藤和成
Original assignee: GS Yuasa International Ltd
Current assignee: GS Yuasa International Ltd
Priority date: 2018-09-25
Filing date: 2019-09-18
Publication date: 2021-05-04
Also published as: SG11202102408TA; JPWO2020066763A1; WO2020066763A1; JP7331856B2

Abstract

The invention provides a lead storage battery, which comprises a negative electrode having a negative electrode mixture containing lead and carbon black, and an electrolyte containing sodium ions, wherein the carbon black has a DBP oil absorption of 170mL/100g or less, and the content of the sodium ions in the electrolyte is more than 0mmol/L and 30mmol/L or less.

Description

Lead-acid battery

Technical Field

The present invention relates to a lead storage battery.

Background

Lead storage batteries are widely used in various applications such as in-vehicle applications and industrial applications. For example, a lead acid battery for vehicle mounting can be used as a power source for driving a battery motor and a power source for electric equipment in a vehicle.

In lead storage batteries, in order to improve various performances, an additive such as carbon is generally added to a negative electrode active material, and an additive such as sodium ions is generally added to an electrolyte solution (see patent documents 1 and 2). Patent document 1 proposes a lead-acid battery in which a sodium lignosulfonate, barium sulfate, and oil furnace carbon black are added to a negative electrode active material. Patent document 2 proposes a lead-acid battery using an electrolyte containing aluminum ions in a range of 0.03 to 0.27mol/L and sodium ions in a range of 0.03 to 0.28 mol/L.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2008-152955

Patent document 2: japanese laid-open patent publication No. 2016-115396

Disclosure of Invention

In lead-acid batteries used in automobiles and the like, it is important that the life of the batteries be long even when the batteries are used in severe environments. However, particularly when overcharging is repeated at high temperatures, the life of the lead-acid battery is shortened due to the progress of corrosion of the positive electrode current collector or the like. Such a high-temperature overcharge life is not yet sufficient in the conventional lead-acid battery.

On the other hand, systems for idling stop of an engine have been widely used for the purpose of improving fuel efficiency of an automobile. In an automobile using these systems, the state of charge (SOC) of the lead storage battery tends to be controlled to a lower range than in the conventional case. Therefore, lead storage batteries are increasingly used in the intermediate SOC. If the lead-acid battery is used at the intermediate SOC, it is difficult to sufficiently recover the capacity thereafter. As a technique for improving the charge acceptance of a lead acid battery used in an idle stop system used in the intermediate SOC, it has been proposed to add Al ions to an electrolyte solution and carbon having a high specific surface area to a negative electrode active material. However, the following new problems are highlighted when idling-stop vehicles are marketed and sold. That is, in an idle-stop vehicle that is stored for a long period of time in a car shop or the like or an idle-stop vehicle that travels for a short distance of about once a week or once a month, the capacity recovery by overdischarge or deep discharge is insufficient, and the life may unexpectedly be long.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a lead-acid battery which has a long high-temperature overcharge life and is sufficient in capacity restorability after overdischarge or deep discharge.

One embodiment of the present invention made to solve the above problems is a lead-acid battery comprising a negative electrode having a negative electrode mixture containing lead and carbon black, and an electrolyte containing sodium ions, wherein the carbon black has a DBP oil absorption of 170mL/100g or less, and the electrolyte contains sodium ions in an amount of more than 0mmol/L and 30mmol/L or less.

According to the present invention, a lead-acid battery having a long high-temperature overcharge life and sufficient capacity restorability even after overdischarge or deep discharge can be provided.

Drawings

Fig. 1 is an exploded perspective view, partially broken away, showing the external appearance and internal structure of a lead-acid battery according to an embodiment of the present invention.

Detailed Description

A lead-acid battery according to one embodiment of the present invention includes a negative electrode having a negative electrode mixture containing lead and carbon black, and an electrolyte containing sodium ions, wherein the carbon black has a DBP oil absorption of 170mL/100g or less, and the electrolyte has a sodium ion content of more than 0mmol/L and 30mmol/L or less.

The lead-acid battery has a long high-temperature overcharge life and also has sufficient capacity restorability after overdischarge or deep discharge. The reason is not clear, but the following reason is presumed. By using carbon black having a small DBP oil absorption as the carbon black contained in the negative electrode mixture and reducing the sodium ion content in the electrolyte, the overcharge charge amount during charging in a high-temperature environment can be suppressed. In such a lead-acid battery, since the accumulated overcharge charge is suppressed, corrosion of the positive electrode current collector is less likely to occur, and the overcharge life at high temperatures is prolonged. In addition, in this lead-acid battery, the electrolyte solution contains sodium ions, so that the capacity recovery after overdischarge or deep discharge is also sufficient. Further, the lead-acid battery has a small amount of decrease in the electrolyte during charge and discharge, and has good charge acceptance.

In the present specification, the DBP oil absorption is a value measured in accordance with JIS K6217-4. The content of each component is a content in a full charge state (SOC 100%). The charging conditions for bringing the lead storage battery into a fully charged state are as follows. In the case of a liquid (vented) battery, the battery was charged at a constant current of 0.2C in a water tank at 25 ℃ until 2.5V/cell, and then further charged at a constant current of 0.2C for 2 hours. In the case of a valve-regulated (sealed) battery, constant-current constant-voltage charging of 0.2C and 2.23V/cell was carried out at 25 ℃ in a gas cell, and the charging was terminated when the charging current in the constant-voltage charging was 1mC or less. Note that 1C is a current value obtained by discharging the battery with a nominal capacity of 1 hour, and for example, if the battery is a battery with a nominal capacity of 30Ah, 1C is 30A.

The content of the carbon black with respect to the lead is preferably 0.01 to 0.6 mass%. By setting the carbon black content to the above range, the overcharge electric quantity during charging in a high-temperature environment can be made more moderate, and the high-temperature overcharge life can be improved more favorably. Further, the content of the carbon black with respect to the lead is more preferably 0.1 to 0.4 mass%. In this case, the high-temperature overcharge life, and the capacity recovery after overdischarge or deep discharge can be made more favorable.

The negative electrode mixture preferably further contains barium sulfate, and the content of barium sulfate with respect to the lead is preferably 0.5 to 10% by mass. Further, the content of barium sulfate with respect to lead is more preferably 2 to 10 mass%. By containing barium sulfate in such an amount in the negative electrode mixture, the high-temperature overcharge life, and the capacity restorability after overdischarge or deep discharge can be further improved. The content of barium sulfate with respect to lead is also preferably 0.5 to 4 mass%. In this case, the capacity restorability after overcharge at high temperature and after overdischarge or deep discharge can be improved, and the amount of reduction of the electrolyte can be reduced.

< lead storage battery >

Hereinafter, a lead-acid battery according to an embodiment of the present invention will be described in detail. A lead-acid battery according to an embodiment of the present invention includes a negative electrode plate as a negative electrode, a positive electrode plate as a positive electrode, and an electrolyte. A separator is disposed between the negative electrode plate and the positive electrode plate. The negative electrode plate, the positive electrode plate, and the separator are immersed in an electrolyte. The lead storage battery may be a liquid lead storage battery or a valve regulated lead storage battery, and preferably is a liquid lead storage battery.

(negative plate)

The negative electrode plate includes a negative electrode current collector and a negative electrode mixture. The negative electrode mixture is held on the negative electrode current collector.

(negative current collector)

The negative electrode current collector is generally in the form of a grid plate. The negative electrode collector may be formed by casting lead (Pb) or a lead alloy, or may be formed by processing a lead or lead alloy sheet. Examples of the processing method include diameter expanding and pressing (punching).

Examples of the lead alloy used for the negative electrode current collector include Pb-Sb alloys, Pb-Ca alloys, and Pb-Ca-Sn alloys. These lead or lead alloy may further contain elements such As Ba, Ag, Al, Bi, As, Se, Cu, etc. As additive elements. The negative electrode current collector may have lead alloy layers having different compositions, and the lead alloy layer may be plural.

(negative electrode mixture)

The negative electrode mixture contains lead and carbon black.

Lead is a component that functions as a negative electrode active material, and is usually a main component in the negative electrode mixture. The content of lead in the negative electrode mixture may be, for example, 90 to 99.99 mass%. A part or all of the lead in the negative electrode mixture may be present as lead sulfate or the like.

The carbon black is present in the negative electrode mixture as particles containing carbon as a main component. The upper limit of the DBP oil absorption of the carbon black contained in the negative electrode mixture is 170mL/100g, preferably 160mL/100g, more preferably 150mL/100g, and still more preferably 140mL/100 g. When the DBP oil absorption of the carbon black is not more than the upper limit, the overcharge life at high temperature tends to be longer and the decrease in the amount of the electrolyte tends to be reduced. The lower limit of the DBP oil absorption of the carbon black is, for example, 50mL/100g, preferably 80mL/100g, more preferably 120mL/100g, and still more preferably 140mL/100 g. When the DBP oil absorption of the carbon black is not less than the lower limit, the capacity restorability after overdischarge or deep discharge, the charge acceptance, and the like tend to be improved by improving the conductivity of the carbon black, and the like.

The lower limit of the content of carbon black with respect to lead (100 mass%) in the negative electrode mixture is preferably 0.01 mass%, more preferably 0.05 mass%, still more preferably 0.1 mass%, and yet more preferably 0.2 mass%. When the content of carbon black is not less than the lower limit, the conductivity of the negative electrode mixture is increased by carbon black, and the capacity restorability and charge acceptance after overdischarge or deep discharge tend to be improved. The upper limit of the content of carbon black with respect to lead (100 mass%) is preferably 0.6 mass%, more preferably 0.5 mass%, and still more preferably 0.4 mass%, 0.3 mass%, or 0.2 mass%. When the content of carbon black is not more than the upper limit, the overcharge electric quantity during charging in a high-temperature environment and the like are sufficiently suppressed, and thus the high-temperature overcharge life tends to be more improved.

The carbon black is not particularly limited as long as it has a DBP oil absorption of 170mL/100g or less, and various carbon blacks can be used. Examples of the carbon black include furnace black, channel black, thermal black, acetylene black, and ketjen black. These can be used alone, also can be used in combination of more than 2.

The DBP oil absorption of carbon black can be adjusted to a desired value by mixing 2 or more commercially available carbon blacks having different DBP oil absorptions.

The negative electrode mixture preferably further contains barium sulfate. By containing barium sulfate, the crystal growth of coarse lead sulfate is suppressed, and the overcharge life, the capacity recovery after overdischarge or deep discharge, the charge acceptance, and the like can be improved.

The lower limit of the content of barium sulfate with respect to lead (100 mass%) in the negative electrode mixture is preferably 0.5 mass%, more preferably 1 mass%, still more preferably 1.5 mass%, and yet more preferably 2 mass%. By setting the content of barium sulfate to the lower limit or more, the effect of barium sulfate can be more sufficiently exhibited. The upper limit of the content of barium sulfate with respect to lead (100 mass%) is preferably 10 mass%, more preferably 5 mass%, even more preferably 4 mass%, and even more preferably 3 mass%. When the content of barium sulfate is not more than the upper limit, the amount of decrease in the electrolytic solution tends to decrease.

Barium sulfate is generally present as particles in the negative electrode mixture. The lower limit of the average primary particle size of barium sulfate is, for example, 0.1. mu.m, preferably 0.2. mu.m. The upper limit of the average primary particle size is 1 μm, preferably 0.5 μm. By using barium sulfate having such a particle diameter, the effect of containing barium sulfate can be more sufficiently exhibited. The average primary particle size of barium sulfate is a value obtained by arbitrarily selecting 20 primary particles of barium sulfate in an enlarged photograph of the negative electrode mixture, and averaging the particle sizes of the selected particles. The particle diameter is the diameter of an equivalent circle having the same area as the projected area of the primary particle of barium sulfate, which can be confirmed from the enlarged photograph.

The negative electrode mixture may contain, in addition to carbon black, other additives such as carbonaceous materials and lignin, if necessary.

(method of manufacturing negative electrode)

The negative electrode plate is obtained by chemical conversion treatment of an unformed negative electrode plate. The unformed negative electrode plate is generally produced using lead powder containing lead monoxide as a main component, which is a raw material of the negative electrode active material. Specifically, the negative electrode current collector is filled with the negative electrode mixture paste, and the resultant mixture is aged and dried by a conventional method to produce an unformed negative electrode plate. The negative electrode mixture paste can be obtained by, for example, mixing carbon black, lignin, and barium sulfate as additives at a predetermined ratio in a lead powder containing lead monoxide as a main component, and then mixing water and 50% dilute sulfuric acid at a predetermined ratio. Aging and drying of the unformed negative plate are preferably performed at a temperature higher than room temperature and at a high humidity.

The obtained unformed negative electrode plate is subjected to chemical conversion treatment, whereby a negative electrode plate in which lead powder is spongy lead can be obtained. The formation may be carried out by immersing the electrode plate group including the non-formed negative electrode plate in an electrolytic solution containing sulfuric acid in the lead-acid storage battery cell and charging the electrode plate group. However, the formation may be performed before the lead-acid battery or the electrode plate group is assembled. By the formation, spongy lead can be produced and used as a negative electrode plate.

(Positive plate)

The positive electrode plate can be classified into a paste type, a coating type, and the like.

The paste-type positive electrode plate generally includes a positive electrode collector in a lattice plate shape and a positive electrode mixture. The positive electrode mixture is held on the positive electrode current collector. The positive electrode current collector may be formed in the same manner as the negative electrode current collector, and may be formed by casting lead or a lead alloy, or by processing a lead or a lead alloy sheet.

The positive electrode plate includes a plurality of porous tubes, a core metal inserted into each tube, a positive electrode mixture filled in the tubes inserted into the core metal, and a connecting seat connecting the plurality of tubes.

The lead alloy used as the positive electrode current collector is preferably a Pb-Ca alloy, a Pb-Ca-Sn alloy, or the like, in view of corrosion resistance and mechanical strength. The positive electrode collector may have lead alloy layers having different compositions, and the lead alloy layer may be plural. The core metal is preferably a Pb-Sb alloy.

The positive electrode mixture contains a positive electrode active material (typically, lead dioxide or lead sulfate). The positive electrode mixture may contain additives such as tin sulfate and red lead, as needed, in addition to the positive electrode active material.

The unformed positive electrode plate of paste type is obtained by filling the positive electrode current collector with the obtained positive electrode mixture paste by a conventional method, aging and drying in the same manner as in the case of the negative electrode plate. The positive electrode material mixture paste is prepared by kneading lead powder, an additive, water, sulfuric acid, and the like. Thereafter, the unformed positive plate was formed. The positive electrode plate of the present invention is formed by filling a porous glass tube into which a core metal is inserted with lead powder or lead powder in a slurry form, and joining a plurality of tube connecting bases.

(electrolyte)

The electrolyte is an aqueous solution comprising sulfuric acid. The electrolyte contains sodium ions. The upper limit of the sodium ion content in the electrolyte solution is 30mmol/L, preferably 20mmol/L, and more preferably 15mmol/L or 10 mmol/L. By setting the content of sodium ions to the upper limit or less, the overcharge life can be improved. In addition, the amount of the electrolyte solution decreased and the charge acceptance tended to be improved. On the other hand, the content of sodium ions in the electrolyte solution may be more than 0mmol/L, and the lower limit of the content is preferably 0.1mmol/L, more preferably 1mmol/L, and still more preferably 3 mmol/L. When the content of sodium ions is not less than the lower limit, the capacity restorability after overdischarge or deep discharge can be further sufficient.

For example, sodium ions can be contained in the electrolyte by adding the salt to the electrolyte as sodium sulfate, sodium carbonate, sodium hydrogen carbonate, or the like.

The electrolyte solution may further contain metal ions other than sodium ions. The upper limit of the total content of metal ions other than sodium ions in the electrolyte is preferably 70mmol/L, more preferably 50mmol/L, and still more preferably 20 mmol/L.

The electrolyte may be gelled as necessary. The degree of gelation is not particularly limited. An electrolyte solution in a gel state in a sol having fluidity may be used, or an electrolyte in a gel state having no fluidity may be used. The lower limit of the specific gravity of the electrolyte at 20 ℃ in the fully charged lead-acid battery is, for example, 1.25g/cm³Preferably 1.28g/cm³. On the other hand, the upper limit of the specific gravity is, for example, 1.35g/cm³Preferably 1.32g/cm³。

(spacer)

For the separator, a nonwoven fabric sheet, a microporous film, or the like can be used. The thickness and the number of the separators inserted between the negative electrode plate and the positive electrode plate may be appropriately selected depending on the inter-electrode distance. The nonwoven fabric sheet is a sheet mainly composed of polymer fibers and glass fibers, and may be formed of a fiber component in an amount of 60 mass% or more, for example. On the other hand, the microporous membrane can be obtained, for example, by extrusion-molding a composition containing a polymer powder, a silica powder and an oil into a sheet shape, and then drawing out the oil to form pores. The material constituting the separator preferably has acid resistance, and the polymer component is preferably a polyolefin such as polyethylene or polypropylene.

(use)

The lead-acid battery has a long high-temperature overcharge life and also has sufficient capacity restorability after overdischarge or deep discharge. Therefore, the lead-acid battery can be widely used for various applications in which a general lead-acid battery for automobiles and the like can be used. In particular, it is preferably used for an idling stop vehicle in which charge and discharge are repeated a plurality of times and sufficient overcharge life, capacity restorability, and the like are required.

Fig. 1 shows an external appearance of an example of a lead-acid battery according to an embodiment of the present invention. The lead storage battery 1 includes an electrode group 11, an electrolytic solution (not shown), and an electrolytic bath 12 for storing them. The inside of the electrolytic bath 12 is divided into a plurality of cell chambers 14 by partition walls 13. Each cell chamber 14 accommodates 1 electrode group 11. The opening of the electrolytic cell 12 is closed by a lid 15 provided with a negative electrode terminal 16 and a positive electrode terminal 17. In the lid 15, each cell chamber is provided with a liquid port plug 18. When replenishing water, the liquid port bolt 18 is removed and the replenishing liquid is replenished. The liquid port plug 18 may have a function of discharging gas generated in the cell chamber 14 to the outside of the battery.

Each of the electrode groups 11 is formed by stacking a plurality of negative electrode plates 2 and positive electrode plates 3 via separators 4. Here, the bag-shaped separator 4 that houses the negative electrode plate 2 is shown, but the form of the separator is not particularly limited. In the cell chamber 14 located at one end of the electrolytic bath 12, the negative electrode banks 6 of the plurality of negative electrode plates 2 connected in parallel are connected to the penetration connector 8, and the positive electrode banks 5 of the plurality of positive electrode plates 3 connected in parallel are connected to the positive electrode posts 7. The positive post 7 is connected to a positive terminal 17 outside the cover 15. In the cell chamber 14 located at the other end of the electrolytic bath 12, the negative electrode compartment 6 is connected to the negative electrode post 9, and the positive electrode compartment 5 is connected to the interconnector 8. The negative electrode tab 9 is connected to a negative electrode terminal 16 outside the cap 15. The through-connectors 8 are connected in series with the electrode plate groups 11 of the adjacent cell compartments 14 through-holes provided in the partition walls 13.

The present invention is not limited to the above embodiments, and various modifications and improvements can be made in addition to the above embodiments. For example, in the above-described embodiments, the positive electrode and the negative electrode are described as the positive electrode plate and the negative electrode plate, respectively, but the positive electrode and the negative electrode are not limited to the plate shape.

Examples

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

< example 1 >

(1) Production of unformed negative electrode plate

Carbon black having a DBP oil absorption of 100mL/100g, barium sulfate having an average primary particle diameter of 0.3 μm, and lignin having a mass average molecular weight of 6000 as additives were mixed in a predetermined ratio with lead powder containing lead monoxide as a main component. To this mixture, water and 50% diluted sulfuric acid were further added at a predetermined ratio and kneaded to obtain a negative electrode mixture paste. The negative electrode mixture paste was filled into the mesh part of an expanded diameter cell made of a Pb-Ca-Sn alloy, and aged and dried to obtain an unformed negative electrode plate.

Carbon black is blended in the negative electrode mix paste so that the content of carbon black relative to lead in the negative electrode mix of a fully charged lead-acid battery after formation is 0.3 mass%. Barium sulfate was added to the negative electrode mixture paste so that the content of barium sulfate with respect to lead in the negative electrode mixture of a fully charged lead-acid battery after chemical conversion was 2.1 mass%.

(2) Production of unformed Positive plate

A positive electrode material mixture paste was obtained by mixing lead powder containing lead monoxide as a main component, water, and 50% diluted sulfuric acid at a predetermined ratio. The positive electrode mixture paste was filled into the mesh portion of the expanded diameter lattice made of a Pb-Ca-Sn alloy, and aged and dried by a conventional method to obtain an unformed positive electrode plate.

(3) Preparation of the electrolyte

A mixture of sulfuric acid, sodium sulfate and sodium carbonate was added to water to prepare an electrolyte having a sodium ion content of 5 mmol/L.

(4) Production of lead-acid battery

The unformed negative electrode plates were contained in a bag-like separator made of a microporous film made of polyethylene, and 7 sheets of the unformed negative electrode plates and 6 sheets of the unformed positive electrode plates were collectively welded to have the same polarity, thereby forming an electrode plate group. The electrode plate group was placed in an electrolytic bath made of polypropylene, and the electrode plate group was welded in series to inject an electrolyte, and formation was performed in the electrolytic bath, thereby assembling the flooded lead acid battery of example 1.

< examples 2 to 26 and comparative examples 1 to 25 >

Lead-acid batteries of examples 2 to 26 and comparative examples 1 to 25 were assembled in the same manner as in example 1, except that the DBP oil absorption of the carbon black used and the contents of carbon black, barium sulfate and sodium ions were changed as described in table 1. The DBP oil absorption of the carbon black can be adjusted by mixing a plurality of commercially available carbon blacks having different DBP oil absorptions.

[ evaluation ]

< overcharge Life >

For each lead-acid battery, a high-temperature overcharge life test was carried out in accordance with JIS-D-5301 (2006). In order to make the deterioration pattern of the lead-acid battery match the actual condition on the market by the light load life test, the discharge time of 25A discharge was changed from 240 seconds to 60 seconds. Specifically, the procedure was as follows.

1) In 75 ℃ atmosphere, 25A x 60 seconds of discharge, 14.8V x 600 seconds of charge repeat 480 cycles.

2) After being left at 75 ℃ for 56 hours, the discharge was carried out for 30 seconds by a cold-start current.

3) The weight of the lead-acid battery was measured at 75 ℃ in an atmosphere, and the weight was measured again after adding water to the upper limit of the electrolyte.

4) The mixture was left at 75 ℃ for 24 hours.

5) Repeating the above 1) to 4) until the discharge voltage at the time of the cold start current discharge of the above 3) is less than 7.2V. The number of repetitions of 1) to 4) above when the discharge voltage is less than 7.2V is used as an index of the high-temperature overcharge life.

< liquid reduction amount >

In the high-temperature overcharge life test, the cumulative amount of make-up water from the start of the test to the end of the life was used as the amount of reduction.

< Charge acceptance >

The charge acceptance test was carried out for each lead-acid battery in accordance with JIS-D-5301 (2006). Specifically, the procedure was as follows.

1) The discharge was carried out at 25 ℃ for 7.2 A.times.2.5 hours.

2) After leaving at 0 ℃ for 12 hours in the atmosphere, charging was carried out for 14.4 V.times.10 minutes, and the charge current value 10 minutes after the start of charging was used as an index of charge acceptance.

< Capacity recovery after over-discharge >

For each lead-acid battery, the capacity recovery after overdischarge was tested in the following procedure.

1) The discharge was carried out at 7.2A in an atmosphere of 25 ℃ until the discharge voltage became 10.5V.

2) A load of 10w was applied under an atmosphere of 40 ℃ and left for 14 days.

3) The load was removed and left for a further 14 days.

4) Charging was carried out at 25 ℃ for 15.0 V.times.4 hours.

5) After the plate was left at-15 ℃ for 16 hours, discharge was carried out with a high discharge current until the discharge voltage became 6.0V. The duration of discharge using a high-rate discharge current was used as an index of the capacity restorability after overdischarge.

The evaluation results are shown in table 1. Each evaluation result is expressed as a relative value based on (100%) comparative example 22.

[ Table 1]

As shown in table 1, the lead-acid batteries of examples 1 to 26 all had results of an overcharge life of 110% or more, a capacity restorability after overdischarge of 85% or more, a long overcharge life at a high temperature, and a sufficient capacity restorability after overdischarge, as compared with comparative example 22. On the other hand, the lead-acid batteries of comparative examples 2, 3, 5, 6, 8, 9, 13 to 16, and 18 to 25, in which the content of sodium ions in the electrolyte was more than 30mmol/L or the DBP oil absorption of carbon black was more than 170mL/100g, had short overcharge lives. In addition, the lead-acid batteries of comparative examples 1, 4, 7, 10 to 12, 17 and 20, which used the electrolyte solution containing no sodium ion, had poor capacity restorability after overdischarge.

Industrial applicability

The lead acid battery of the present invention can be used as a power source for automobiles, motorcycles, electric vehicles (e.g., forklift trucks), industrial power storage devices, and the like, and is particularly preferably used as a power source for idle stop vehicles.

Description of the reference numerals

1 lead accumulator

2 negative plate

3 Positive plate

4 spacer

5 positive pole shed

6 negative electrode shed

7 positive pole

8-pass-through connector

9 negative pole column

11 polar plate group

12 electrolytic cell

13 bulkhead

14 single cell chamber

15 cover

16 negative terminal

17 positive terminal

18 liquid mouth bolt

Claims

1. A lead-acid battery is provided with:

a negative electrode having a negative electrode mixture containing lead and carbon black, and

an electrolyte containing sodium ions;

the carbon black has a DBP oil absorption of 170mL/100g or less,

the content of sodium ions in the electrolyte is more than 0mmol/L and less than 30 mmol/L.

2. The lead storage battery according to claim 1, wherein the content of the carbon black with respect to the lead is 0.01 to 0.6 mass%.

3. The lead storage battery according to claim 2, wherein the content of the carbon black with respect to the lead is 0.1 to 0.4 mass%.

4. The lead storage battery according to any one of claims 1 to 3, wherein the negative electrode mix further contains barium sulfate,

the content of the barium sulfate with respect to the lead is 0.5 to 10 mass%.

5. The lead storage battery according to claim 4, wherein the content of the barium sulfate with respect to the lead is 2 to 10 mass%.

6. The lead storage battery according to claim 4, wherein the content of the barium sulfate with respect to the lead is 0.5 to 4 mass%.