Lead-acid battery

Abstract

A lead-acid battery according to the present invention includes an electrode plate group and an electrolyte solution. The electrode plate group includes a positive electrode plate that includes a positive electrode material, a negative electrode plate that includes a negative electrode material, and a separator that is interposed between the positive electrode plate and the negative electrode plate. The negative electrode material includes a first carbonaceous material that has a particle diameter of less than 32 μm and a C8–30 fatty acid. The first carbonaceous material content Cc of the negative electrode material is at least 0.4 mass%. When the mass-based fatty acid content of the negative electrode material is Cf (ppm), the specific surface area of the negative electrode material is Sn (m2 / g), and the DBP oil absorption of the first carbonaceous material is Y, the lead-acid battery satisfies at least one of condition (i) and condition (ii). (i) Cf / Y is at least 0.1 ppm⋅mL-1⋅100 g. (ii) Cf / Sn is at least 20 ppm⋅m-2⋅g.

Description

lead acid battery

[0001] The present invention relates to a lead-acid battery.

[0002] Lead-acid batteries are used in a variety of applications, including automotive and industrial applications. A lead-acid battery includes a negative electrode plate, a positive electrode plate, and an electrolyte. The negative electrode plate includes a current collector and a negative electrode material. The negative electrode material includes a carbonaceous material, an organic shrinkage inhibitor, and the like. To impart various functions to the battery, additives may be added to the components of the lead-acid battery.

[0003] Patent Document 1 proposes a flooded lead-acid battery comprising a negative electrode active material, a positive electrode active material mainly composed of lead dioxide, and a freely flowing electrolyte containing sulfuric acid, wherein the negative electrode active material contains sponge lead, carbon, a bisphenol-based condensate, and alginic acid or an alkali metal salt thereof.

[0004] Patent Document 2 proposes a flooded lead-acid battery manufactured by a so-called container formation method, in which a battery is fabricated using unformed positive and negative electrode plates, and then a predetermined amount of dilute sulfuric acid is poured into the battery and a current is passed through to form the electrode plate group in a container, and the flooded lead-acid battery is characterized by using a negative electrode active material to which a fatty acid has been added.

[0005] Patent Document 3 proposes a ready-to-use lead-acid battery characterized by including a ready-to-use negative electrode plate which is obtained by thoroughly washing a charged negative electrode plate with water, immersing it in a 0.5 to 3% emulsion liquid obtained by adding water to an alcohol solution of diterpene acid, and then drying it for ready use.

[0006] International Publication No. 2014 / 050012 JP 10-302785 A JP 50-076535 A

[0007] Lead-acid batteries are sometimes used in a state of insufficient charge known as a partial state of charge (PSOC). Examples of applications in which charging and discharging are controlled by PSOC include idling stop (also known as start-stop or idle reduction), charge control, and vehicle accessory applications. Repeated charging and discharging of lead-acid batteries in PSOC facilitates the accumulation of lead sulfate, resulting in a reduction in lifespan. Adding a carbonaceous material to the negative electrode material is effective in reducing lead sulfate accumulation. However, adding a carbonaceous material to the negative electrode material in an amount sufficient to inhibit lead sulfate accumulation significantly increases the amount of carbonaceous material leaching into the electrolyte. The leaching of the carbonaceous material into the electrolyte clouds the electrolyte, reducing the visibility of the liquid level sensor. In this specification, idling stop is sometimes simply referred to as IS.

[0008] A first aspect of the present disclosure is a lead-acid battery, the lead-acid battery including a plate assembly and an electrolyte, the plate assembly including positive plates including a positive electrode material, negative plates including a negative electrode material, and a separator interposed between the positive electrode plates and the negative electrode plates, the negative electrode material including a first carbonaceous material having a particle size of less than 32 μm and a fatty acid having a carbon number of 8 to 30, a content Cc1 of the first carbonaceous material in the negative electrode material being 0.4 mass% or more, a mass-based content Cf (ppm) of the fatty acid in the negative electrode material being 0.5 mass% or more, and a specific surface area Sn (m ２ / g), the ratio of the content Cf to the specific surface area Sn: Cf / Sn is 20 ppm m －２ g or more.

[0009] A second aspect of the present invention is a lead-acid battery, the lead-acid battery including a plate assembly and an electrolyte, the plate assembly including positive plates including a positive electrode material, negative plates including a negative electrode material, and a separator interposed between the positive electrode plates and the negative electrode plates, the negative electrode material including a first carbonaceous material having a particle size of less than 32 μm and a fatty acid having 8 to 30 carbon atoms, a content Cc1 of the first carbonaceous material in the negative electrode material is 0.4 mass% or more, and when the mass-based content of the fatty acid in the negative electrode material is Cf (ppm) and the DBP (Dibutyl phthalate) oil absorption of the first carbonaceous material is Y, a ratio Cf / Y of the content Cf to the DBP oil absorption Y is 0.1 ppm mL －１ - Lead-acid batteries weighing 100g or more.

[0010] In a lead-acid battery, the outflow of carbonaceous material from the negative electrode plate can be suppressed.

[0011] 1 is a partially cutaway exploded perspective view showing the appearance and internal structure of a lead-acid battery according to one embodiment of the present invention.

[0012] The novel features of the present invention are set forth in the appended claims, but the present invention, both in terms of structure and content, together with other objects and features of the present invention, will be better understood from the following detailed description taken in conjunction with the drawings.

[0013] In a lead-acid battery, when the negative electrode material contains a carbonaceous material (sometimes referred to as the first carbonaceous material) having a particle size of less than 32 μm, the conductivity of the negative electrode material is improved, resulting in increased charge acceptance. Even when the lead-acid battery is used in a PSOC, lead sulfate is more easily reduced to lead during charging, reducing the accumulation of lead sulfate and suppressing a decrease in lifespan performance. When the content of the first carbonaceous material in the negative electrode material is high, high charge acceptance is likely to be achieved. However, when the content of the first carbonaceous material is high, the outflow of the first carbonaceous material from the negative plate to the electrolyte becomes significant. In particular, when the negative plate is formed in a battery container, gassing is likely to occur during formation, resulting in significant outflow of the first carbonaceous material near the surface of the negative plate. When the content of the first carbonaceous material in the negative electrode material is high, the amount of the first carbonaceous material that flows out from near the surface also increases. When the outflow of the first carbonaceous material becomes significant, the turbidity of the electrolyte also becomes significant. Furthermore, if a large amount of the first carbonaceous material flows into the electrolyte, it will adhere to the inner wall of the battery container, the liquid level sensor, etc. As a result, the visibility of the liquid level sensor will decrease.

[0014] In view of the above, [1] a lead-acid battery according to a first aspect of the present invention includes a plate assembly and an electrolyte. The plate assembly includes positive plates containing a positive electrode material, negative plates containing a negative electrode material, and a separator interposed between the positive and negative electrode plates. The negative electrode material includes a first carbonaceous material having a particle size of less than 32 μm and a fatty acid having 8 to 30 carbon atoms. The content Cc1 of the first carbonaceous material in the negative electrode material is 0.4 mass% or more. Hereinafter, the fatty acid having 8 to 30 carbon atoms will be referred to as the first fatty acid.

[0015] In the lead-acid battery according to the first aspect, the mass-based content of the first fatty acid in the negative electrode material is Cf (unit: ppm), and the specific surface area of ​​the negative electrode material is Sn (unit: m ２ / g), the ratio of the content Cf to the specific surface area Sn: Cf / Sn is 20 ppm m －２ ・g or more.

[0016] [2] A lead-acid battery according to a second aspect of the present invention includes a plate assembly and an electrolyte. The plate assembly includes positive plates containing a positive electrode material, negative plates containing a negative electrode material, and a separator interposed between the positive and negative electrode plates. The negative electrode material includes a first carbonaceous material having a particle size of less than 32 μm and a first fatty acid. The content Cc1 of the first carbonaceous material in the negative electrode material is 0.4 mass% or more.

[0017] In the lead-acid battery according to the second aspect, when the mass-based content of the first fatty acid in the negative electrode material is Cf (unit: ppm) and the DBP oil absorption of the first carbonaceous material is Y (unit: mL / 100 g), the ratio of the content Cf to the DBP oil absorption: Cf / Y is 0.1 ppm mL －１ ・100g or more.

[0018] When the content Cc1 of the first carbonaceous material in the negative electrode material is 0.4 mass % or more, outflow of the first carbonaceous material into the electrolyte solution is likely to become noticeable, and the turbidity of the electrolyte solution is likely to become significant. Even in such a case, in the first and second aspects of the present invention, －２ g and Cf / Y≧0.1 ppm mL －１ By including the first fatty acid in the negative electrode material so as to satisfy at least one of the following conditions: 100 g / cm 2 , the outflow of the carbonaceous material into the electrolyte can be reduced, and the turbidity of the electrolyte can be reduced, thereby suppressing a decrease in the visibility of the liquid level sensor.

[0019] The fatty acid has a structure having one carboxy group in a hydrocarbon. Because the first fatty acid has 8 to 30 carbon atoms, the hydrocarbon portion is thought to selectively adhere to particles of the first carbonaceous material (hereinafter simply referred to as the first carbonaceous particles) more easily than to lead contained in the negative electrode material. Furthermore, the carboxy group of the first fatty acid interacts with hydroxy groups or water contained in the oxide layer or adsorbed water layer formed on the surface of the lead through at least one of covalent bonds and hydrogen bonds, thereby providing a binding effect. The binding effect of the carboxy group of the first fatty acid and the hydrocarbon portion attached to the first carbonaceous particles are thought to suppress the outflow of the first carbonaceous particles. Because the first fatty acid has a lower molecular weight than general polymer binders, it is expected to be more easily eluted into the electrolyte than polymer binders. Furthermore, the balance between the hydrophobicity of the hydrocarbon portion and the hydrophilicity of the carboxy group is thought to be important for the outflow suppression effect of the first carbonaceous particles. However, contrary to expectations, because the first fatty acid has 8 to 30 carbon atoms and one carboxyl group, the first fatty acid adheres to the first carbonaceous particles and lead, suppressing the elution of the first fatty acid itself into the electrolyte and providing a binding effect, which is thought to result in an effect of suppressing the outflow of the first carbonaceous particles.

[0020] On the other hand, polymer binders such as carboxymethylcellulose (CMC), sodium alginate, and polyacrylic acid are believed to have the effect of suppressing the outflow of the first carbonaceous particles. These binders have multiple carboxy groups and may also have hydrophilic groups other than carboxy groups. The action of these multiple hydrophilic groups causes them to gel with water molecules under acidic conditions. Therefore, it is believed that the above binders bond like glue to the oxide layer or adsorbed water layer formed on the surface of lead through hydrogen bonds via the gelled water molecules.

[0021] In the case of the first fatty acid, due to the hydrophobicity of the hydrocarbon portion, gelation does not occur as occurs with the above-mentioned polymer binder. In other words, the mechanisms by which the binding action is exerted differ between the first fatty acid and the above-mentioned polymer binder. Due to this difference in mechanism, in the case of the first fatty acid, the binding effect of the first carbonaceous particles is easily affected by the specific surface area Sn of the negative electrode material or the DBP oil absorption Y of the carbonaceous material. In the first and second aspects of the present invention, the content of the first fatty acid is determined according to at least one of the specific surface area Sn of the negative electrode material and the DBP oil absorption Y of the carbonaceous material. Therefore, the first fatty acid can be used to obtain a high effect of suppressing the outflow of the first carbonaceous material.

[0022] Generally, in a negative electrode material, when the surface of lead is covered with an organic component, the charge acceptance decreases. In contrast, the first and second aspects of the present invention can reduce the decrease in charge acceptance in the negative electrode plate. This is thought to be because the first fatty acid has a lower molecular weight than a polymer binder such as CMC, does not cause gelation, and the hydrocarbon portion of the first fatty acid easily adheres to the first carbonaceous material, resulting in a thin layer of fatty acid adhering to the lead surface.

[0023] Generally, an increase in the specific surface area of ​​a negative electrode material leads to an increase in charge acceptance and an increase in the amount of electricity in overcharge. In contrast, in the first and second aspects of the present invention, the carboxyl group of the first fatty acid thinly covers the surface of the lead, thereby suppressing a decrease in charge acceptance and reducing side reactions during overcharge, thereby reducing the amount of electricity in overcharge. Therefore, a relatively high charge acceptance can be ensured while reducing the amount of electricity in overcharge.

[0024] [3] In the first aspect of the present invention described in [1] above, the ratio Cf / Sn is 1000 ppm m －２ When the ratio Cf / Sn is in this range, it is easy to ensure higher charge acceptance.

[0025] [4] In any one of the above [1] to [3], the lead-acid battery has Cf / Sn≧20 ppm m －２ g and Cf / Y≧0.1 ppm mL －１When both of the amounts are 100 g, the effect of suppressing the outflow of the first carbonaceous material into the electrolyte is further enhanced.

[0026] [5] In any one of the above [1] to [4], the ratio Cf / Y is 12 ppm mL －１ The ratio Cf / Y may be 100 g or less. When the ratio Cf / Y is in this range, it is easy to ensure higher charge acceptance.

[0027] [6] In any one of the above [1] to [5], the ratio Cf / Y is 0.12 ppm mL －１ The weight may be 100 g or more. In this range, the amount of overcharged electricity can be further reduced.

[0028] [7] In any one of the above [1] to [6], the content Cf of the first fatty acid may be 20 ppm or more and 600 ppm or less by mass. When Cf is in this range, the effect of suppressing the outflow of carbonaceous material and the effect of reducing the amount of electricity in overcharge are excellent, and higher charge acceptance is easily ensured. In other words, it is easy to balance these properties.

[0029] [8] In any one of the above [1] to [7], the content Cc1 of the first carbonaceous material is preferably 2 mass% or less. When Cc1 is in this range, it is easy to ensure high charge acceptance while suppressing leakage of the first carbonaceous material into the electrolyte solution.

[0030] [9] In any one of the above [1] to [8], the first carbonaceous material may contain carbon black. Carbon black has a developed secondary particle structure, which tends to increase the specific surface area Sn of the negative electrode material or the DBP oil absorption Y of the first carbonaceous material. Even when carbon black is used in the negative electrode material, by determining the content Cf of the first fatty acid in accordance with the specific surface area Sn or the DBP oil absorption Y, a high binding effect of the first fatty acid on the first carbonaceous material can be obtained, and leakage of the first carbonaceous material into the electrolyte can be reduced.

[0031]

[10] In any one of the above [1] to [9], the negative electrode material may further include a second carbonaceous material having a particle diameter of 32 μm or more. When the negative electrode material includes the second carbonaceous material, the life performance when repeatedly charged and discharged in PSOC (hereinafter, sometimes referred to as PSOC life performance) can be improved.

[0032]

[11] In the above

[10] , the second carbonaceous material may contain graphite. In this case, PSOC life performance can be further improved.

[0033] The lead-acid batteries of the first and second aspects of the present invention may be valve regulated lead-acid batteries (VRLA), but are particularly suited to flooded (vented) lead-acid batteries. VRLA are also known as sealed lead-acid batteries.

[0034] The content Cc1 of the first carbonaceous material in the negative electrode material, the content Cf of the first fatty acid, the specific surface area Sn of the negative electrode material, and the DBP oil absorption Y of the first carbonaceous material are each values ​​determined for the negative electrode material sampled from a negative electrode plate removed from a fully charged lead-acid battery.

[0035] In this specification, the specific surface area Sn of the negative electrode material refers to the specific surface area (BET specific surface area) measured by the BET (Brunauer-Emmett-Teller) method (unit: m ２ The BET specific surface area is a specific surface area determined by the BET equation using a gas adsorption method in which nitrogen gas is used as the adsorption gas.

[0036] The DBP oil absorption represents the amount (mL) of dibutyl phthalate (DBP) that 100 g of powder adsorbs or absorbs. Therefore, the unit of DBP oil absorption is expressed in mL / 100 g. The method for measuring DBP oil absorption is specified in JIS K 6217-4-2017. In the first carbonaceous material, primary particles aggregate to form secondary particles, and DBP may be absorbed in the voids between the primary particles in the secondary particles, and these voids are reflected in the DBP oil absorption.

[0037] The negative and positive electrode materials are typically held by current collectors. The electrode material is the portion of the electrode plate excluding the current collector. A mat, pasting paper, or other material may be attached to the electrode plate. Such material (also referred to as an attachment material) is included in the electrode plate because it is used integrally with the electrode plate. When the electrode plate includes an attachment material (such as a mat or pasting paper), the electrode material is the portion of the electrode plate excluding the current collector and the attachment material. Among positive electrode plates, a clad positive electrode plate includes multiple porous tubes, a core inserted into each tube, a current collector connecting the multiple cores, a positive electrode material filled into the tube with the cores inserted, and a connecting seat connecting the multiple tubes. In a clad positive electrode plate, the positive electrode material is the portion of the electrode plate excluding the tube, core, current collector, and connecting seat. In a clad type positive electrode plate, the core metal and the current collecting portion are sometimes collectively referred to as a positive electrode current collector.

[0038] The fully charged state of a flooded lead-acid battery is defined by JIS D 5301:2019. More specifically, the fully charged state is defined as a state in which a lead-acid battery is charged in a water tank at 25°C ± 2°C at a current (A) 0.2 times the value (unit: Ah) specified for the rated capacity until the terminal voltage (V) during charging or the electrolyte density converted to a temperature of 20°C, measured every 15 minutes, shows a constant value to three significant digits three times consecutively. For a valve-regulated lead-acid battery, the fully charged state is defined as a state in which constant-current, constant-voltage charging of 2.23 V / cell is performed in an air tank at 25°C ± 2°C at a current (A) 0.2 times the value (unit: Ah) specified for the rated capacity, and charging is terminated when the charging current during constant-voltage charging reaches a value (A) 0.005 times the value (unit: Ah) specified for the rated capacity.

[0039] A fully charged lead-acid battery refers to a lead-acid battery that has been fully charged after chemical formation. A lead-acid battery can be fully charged immediately after chemical formation, or after some time has passed since chemical formation (for example, a lead-acid battery that has been in use (preferably in the early stages of use) after chemical formation can be fully charged). A battery in the early stages of use refers to a battery that has not been in use for very long and has hardly deteriorated.

[0040] In this specification, the up-down direction of a lead-acid battery or its components (such as plates, a battery case, and a separator) refers to the up-down direction in the vertical direction of the lead-acid battery when the battery is in use. Each of the positive and negative plates has a lug for connecting to an external terminal. In some cases, such as horizontally placed valve-regulated lead-acid batteries, the lug is provided on the side of the plate so as to protrude laterally, but in most lead-acid batteries, the lug is usually provided on the top of the plate so as to protrude upward.

[0041] The lead-acid batteries according to the first and second aspects of the present invention will be described in more detail below for each of their main constituent features, including the above [1] to

[11] . At least one of the above [1] to

[11] may be combined with at least one of the elements described below, provided that no technical contradiction occurs.

[0042] [Lead-acid battery] (Negative electrode plate) The negative electrode plate usually includes a negative electrode current collector in addition to a negative electrode material.

[0043] (Negative electrode current collector) The negative electrode current collector may be formed by casting lead (Pb) or a lead alloy, or by processing a lead sheet or a lead alloy sheet. Examples of processing methods include expanding and punching. It is preferable to use a lattice-shaped current collector as the negative electrode current collector because it is easy to support the negative electrode material.

[0044] The lead alloy used for the negative electrode current collector may be any of a Pb—Sb-based alloy, a Pb—Ca-based alloy, and a Pb—Ca—Sn (tin)-based alloy. These lead or lead alloys may further contain at least one additive element selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu, and the like. The negative electrode current collector may have a surface layer. The surface layer and the inner layer of the negative electrode current collector may have different compositions. The surface layer may be formed so as to cover the entire negative electrode current collector, or may be formed on only a portion of the negative electrode current collector. The surface layer may be formed on an edge portion of the negative electrode current collector. The surface layer of the edge portion may contain Sn (tin) or a Sn (tin) alloy.

[0045] (Negative Electrode Material) The negative electrode material includes a first carbonaceous material and a first fatty acid. The negative electrode material further includes a negative electrode active material (specifically, lead or lead sulfate) that exhibits capacity through an oxidation-reduction reaction. The negative electrode material may further include a second carbonaceous material. The negative electrode material may also include additives other than the first carbonaceous material, the second carbonaceous material, and the first fatty acid. Examples of such additives include, but are not limited to, organic shrinkage inhibitors, barium sulfate, and fibers (such as resin fibers). Note that the negative electrode active material in a charged state is sponge lead, but unformed negative electrode plates are typically made using lead powder.

[0046] (Carbonaceous Material) The carbonaceous material contained in the negative electrode material includes at least a first carbonaceous material, and may include the first carbonaceous material and a second carbonaceous material.

[0047] The content Cc1 of the first carbonaceous material in the negative electrode material is 0.4% by mass or more, and may be 0.5% by mass or more. When the content Cc1 is in this range, the outflow of the first carbonaceous material into the electrolyte solution is likely to become significant. In the first and second aspects of the present invention, the outflow of the first carbonaceous material into the electrolyte solution in such cases can be reduced. Also, high charge acceptance is likely to be ensured. The content Cc1 may be 5% by mass or less, or may be 3% by mass or less. From the viewpoint of easily ensuring high charge acceptance while suppressing low outflow of the first carbonaceous material into the electrolyte solution, the content Cc1 is preferably 2% by mass or less.

[0048] The content Cc1 of the first carbonaceous material may be 0.4 mass% or more (or 0.5 mass% or more) and 5 mass% or less, 0.4 mass% or more (or 0.5 mass% or more) and 3 mass% or less, or 0.4 mass% or more (or 0.5 mass% or more) and 2 mass% or less.

[0049] The first carbonaceous material preferably contains at least carbon black. Carbon black has a developed secondary particle structure, which is likely to affect the binding ability of the first fatty acid. Even in such a case, by determining the content Cf of the first fatty acid in accordance with at least one of the specific surface area Sn of the negative electrode material and the DBP oil absorption Y of the carbonaceous material, an excellent effect of suppressing outflow of the first carbonaceous material into the electrolyte can be obtained.

[0050] Examples of carbon black include acetylene black, furnace black, and lamp black. Furnace black also includes Ketjen Black (trade name). The negative electrode material may contain one or more first carbonaceous materials (e.g., these carbon blacks) in combination.

[0051] The specific surface area Sc of the first carbonaceous material is, for example, 20 m ２ / g or more, and ２ / g or more or 28m ２ When the specific surface area Sc is in this range, it is easy to prevent the content of the first fatty acid from becoming excessively high, and it is easy to ensure high charge acceptance. The specific surface area Sc of the first carbonaceous material is, for example, 1500 m ２ / g or less, and ２ From the viewpoint of further suppressing the outflow of the first carbonaceous material, the specific surface area Sc may be 800 m ２ / g or less is preferable, and 200m ２ / g or less or 150m ２ / g or less.

[0052] In this specification, the specific surface area Sc of the first carbonaceous material is the specific surface area (BET specific surface area) (unit: m ２ The specific surface area Sc of the carbonaceous material is a value determined for a negative electrode plate taken out of a fully charged lead-acid battery.

[0053] The specific surface area Sc of the first carbonaceous material is 20 m ２ / g or more (or 25m ２ / g or more) 1500m ２ / g or less, 20m ２ / g or more (or 25m ２ / g or more) 1300m ２ / g or less, 20m ２ / g or more (or 25m ２ / g or more) 800m ２ / g or less, 20m ２ / g or more (or 25m ２ / g or more) 200m ２ / g or less, 20m ２ / g or more (or 25m ２ / g or more) 150m ２ / g or less, 28m ２ / g or more 1500m ２ / g or less (or 1300m ２ / g or less), 28m ２ / g or more 800m ２ / g or less (or 200m ２ / g or less), or 28m ２ / g or more 150m ２ / g or less.

[0054] The DBP oil absorption Y of the first carbonaceous material is, for example, 30 mL / 100 g or more, and may be 50 mL / 100 g or more, or may be 65 mL / 100 g or more. When the DBP oil absorption Y is in such a range, it is easy to prevent the content of the first fatty acid from becoming excessively high, and high charge acceptance is easy to ensure. In addition, the effect of suppressing leakage of the first carbonaceous material into the electrolyte solution is further enhanced. The DBP oil absorption Y of the first carbonaceous material is, for example, 600 mL / 100 g or less, or may be 500 mL / 100 g or less. From the viewpoint of further suppressing leakage of the first carbonaceous material, the DBP oil absorption Y is preferably 400 mL / 100 g or less, and may be 360 ​​mL / 100 g or less, or may be 200 mL / 100 g or less.

[0055] The DBP oil absorption Y is 30 mL / 100 g or more and 600 mL / 100 g or less (or 500 mL / 100 g or less), 30 mL / 100 g or more and 400 mL / 100 g or less (or 360 mL / 100 g or less), 30 mL / 100 g or more (or 50 mL / 100 g or more) and 200 mL / 100 g or less, 50 mL / 100 g or more and 600 mL / 100 g or less (or 500 mL / 100 g or less). 00g or less), 50mL / 100g to 400mL / 100g (or 360mL / 100g or less), 65mL / 100g to 600mL / 100g (or 500mL / 100g or less), 65mL / 100g to 400mL / 100g (or 360mL / 100g or less), or 65mL / 100g to 200mL / 100g.

[0056] Examples of the second carbonaceous material include graphite, hard carbon, and soft carbon. The negative electrode material may contain one type of second carbonaceous material, or two or more types in combination. The combined use of the first carbonaceous material and the second carbonaceous material can improve PSOC life performance. From the viewpoint of easily ensuring a higher PSOC life performance, it is preferable that the second carbonaceous material contains at least graphite.

[0057] In addition, among the second carbonaceous materials, the Raman spectrum of 1300 cm －１ 1350cm or more －１ The peaks appearing in the following range (D band) and 1550 cm －１ More than 1600cm －１ Intensity ratio I to the peak (G band) appearing in the following range Ｄ / I Ｇ A carbonaceous material having a σ of 0 or more and 0.9 or less is called graphite. The graphite may be either artificial graphite or natural graphite.

[0058] The content Cc2 of the second carbonaceous material in the negative electrode material may be 0.01% by mass or more, or may be 0.05% by mass or more. When the content Cc2 is in this range, higher PSOC life performance is likely to be obtained while suppressing outflow of the first carbonaceous material into the electrolyte. High charge acceptance is also likely to be obtained. From the viewpoint of easily keeping the overcharge quantity of electricity low, the content Cc2 may be 0.5% by mass or less, or may be 0.1% by mass or less.

[0059] The content Cc2 of the second carbonaceous material in the negative electrode material may be 0.01 mass % or more (or 0.05 mass % or more) and 0.5 mass % or less, or 0.01 mass % or more (or 0.05 mass % or more) and 0.1 mass % or less.

[0060] The proportion of the first carbonaceous material (such as carbon black) in the entire carbonaceous material (e.g., the total amount of the first carbonaceous material and the second carbonaceous material) is, for example, 50 mass% or more, or may be 75 mass% or more, 80 mass% or more, or 90 mass% or more. When the proportion of the first carbonaceous material (such as carbon black) is within this range, the outflow of the first carbonaceous material into the electrolyte solution tends to be significant. However, even in such a case, an excellent outflow suppression effect can be obtained. Furthermore, higher charge acceptance can be ensured. The proportion of the first carbonaceous material (such as carbon black) in the entire carbonaceous material (e.g., the total amount of the first carbonaceous material and the second carbonaceous material) is, for example, 100 mass% or less, or may be 95 mass% or less. The carbonaceous material may be composed solely of the first carbonaceous material (or carbon black). The carbonaceous material may include at least carbon black and graphite.

[0061] The proportion of the first carbonaceous material (such as carbon black) in the entire carbonaceous material (for example, the total amount of the first carbonaceous material and the second carbonaceous material) may be 50% by mass or more and 100% by mass or less (or 95% by mass or less), 75% by mass or more and 100% by mass or less (or 95% by mass or less), 80% by mass or more and 100% by mass or less (or 95% by mass or less), or 90% by mass or more and 100% by mass or less (or 95% by mass or less).

[0062] (First Fatty Acid) The number of carbon atoms in the first fatty acid is 8 or more, preferably 9 or more. The number of carbon atoms in the first fatty acid is 30 or less, may be 24 or less, or may be 20 or less. By using the first fatty acid, elution of the first fatty acid into the electrolyte solution is suppressed and high binding ability to the carbonaceous material can be ensured, thereby obtaining an excellent effect of suppressing the outflow of the carbonaceous material. The first fatty acid may be contained in the electrolyte solution of a lead-acid battery. In this case, for example, an electrolyte solution prepared using the first fatty acid may be used in assembling a lead-acid battery. Alternatively, an electrolyte solution prepared using a compound capable of generating the first fatty acid in the electrolyte solution of a lead-acid battery may be used in assembling a lead-acid battery. Examples of such compounds include esters of the first fatty acid (e.g., alkyl esters). Such compounds may be capable of generating the first fatty acid, for example, when preparing an electrolyte solution. In the alkyl ester, the number of carbon atoms in the alkyl is not particularly limited and may be, for example, 1 to 30.

[0063] The first fatty acid may have 8 or more (or 9 or more) and 30 or less carbon atoms, 8 or more (or 9 or more) and 24 or less carbon atoms, or 8 or more (or 9 or more) and 20 or less carbon atoms.

[0064] The first fatty acid may be saturated or unsaturated. The number of carbon-carbon unsaturated bonds contained in the first fatty acid is, for example, 6 or less, 4 or less, or 2 or less, depending on the number of carbon atoms in the first fatty acid. The number of carbon-carbon unsaturated bonds contained in the first fatty acid may be 1 or more. From the viewpoint of easily achieving a balance between the state of adhesion to the carbonaceous material and lead, it is preferable that the fatty acid has no substituents other than one carboxy group.

[0065] Specific examples of first fatty acids include octanoic acid, nonanoic acid (pelargonic acid), capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid, arachidonic acid, behenic acid, eicosaheptaenoic acid, and docosahexaenoic acid.

[0066] The negative electrode material may contain one type of first fatty acid or a combination of two or more types.

[0067] The content Cf of the first fatty acid in the negative electrode material is, for example, 15 ppm or more by mass. Although it depends on the specific surface area Sn of the negative electrode material or the DBP oil absorption Y of the carbonaceous material, from the viewpoint of easily obtaining a higher effect of suppressing outflow of the carbonaceous material and a higher effect of reducing the overcharge electricity quantity, Cf is preferably 20 ppm or more by mass, and may be 50 ppm or more. Cf is, for example, 1000 ppm or less by mass. Although it depends on the specific surface area Sn of the negative electrode material or the DBP oil absorption Y of the first carbonaceous material, from the viewpoint of easily obtaining a higher charge acceptance, Cf is preferably 600 ppm or less by mass.

[0068] The content Cf of the first fatty acid in the negative electrode material may be, on a mass basis, 15 ppm to 1000 ppm (or 600 ppm or less), 20 ppm to 1000 ppm (or 600 ppm or less), or 50 ppm to 1000 ppm (or 600 ppm or less).

[0069] The ratio Cf / Sn is 20 ppm m －２ From the viewpoint of easily ensuring a higher outflow suppression effect of the first carbonaceous material, the ratio Cf / Sn is 23 ppm m or more. －２ As the ratio Cf / Sn increases, the effect of suppressing the outflow of the first carbonaceous material tends to improve, but the charge acceptance tends to decrease. From the viewpoint of easily ensuring higher charge acceptance, the ratio Cf / Sn may be 1000 ppm m －２ g or less, and 910 ppm m －２ The ppm in the unit of the ratio Cf / Sn is based on the mass content of Cf, and therefore is based on mass.

[0070] The ratio Cf / Sn is 20 ppm m －２ g or more (or 23 ppm m －２ ・g or more) 1000ppm・m －２ g or less, or 20 ppm m －２ g or more (or 23 ppm m －２ ・g or more) 910ppm・m －２ ・It may be less than g.

[0071] The ratio Cf / Y is 0.1 ppm mL －１ The ratio Cf / Y may be 100 g or more. When the ratio Cf / Y is in this range, a high effect of suppressing the outflow of the first carbonaceous material can be obtained. From the viewpoint of further reducing the overcharge quantity of electricity, the ratio Cf / Y is 0.12 ppm mL －１ The ratio Cf / Y may be 12 ppm mL or more, for example. －１ ・100g or less, 9.5 ppm mL －１ The charge acceptance may be 100 g or less. In this case, it is easy to ensure higher charge acceptance. From the viewpoint of further improving charge acceptance, the ratio Cf / Y is 5 ppm mL －１ ・100g or less or 3.5 ppm mL －１ The ratio Cf / Y may be 100 g or less. Note that the ppm in the unit of the ratio Cf / Y is based on the mass content of Cf, and is therefore based on mass.

[0072] The ratio Cf / Y is 0.1 ppm mL －１ ・100g or more (or 0.12 ppm mL －１ ・100g or more) 12ppm・mL －１ ・100g or less, 0.1ppm・mL －１ ・100g or more (or 0.12 ppm mL －１ ・100g or more) 9.5ppm・mL －１ ・100g or less, 0.1ppm・mL －１ ・100g or more (or 0.12 ppm mL －１ ・100g or more) 5ppm・mL －１ ・100g or less, or 0.1 ppm mL －１ ・100g or more (or 0.12 ppm mL －１ ・100g or more) 3.5ppm・mL －１ ・It may be less than 100g.

[0073] (Organic Shrinkage Resistant) Examples of organic shrinkage resistants include lignin compounds and synthetic organic shrinkage resistants. Examples of lignin compounds include lignin and lignin derivatives (for example, lignin sulfonic acid or its salts (such as alkali metal salts such as sodium salts)). Synthetic organic shrinkage resistants are organic polymers containing elemental sulfur. Examples of synthetic organic shrinkage resistants include condensates of compounds having a sulfur-containing group and an aromatic ring (such as phenol compounds and aniline compounds) with aldehyde compounds (aldehydes or condensates thereof, such as formaldehyde). However, the organic shrinkage resistant is not limited to these specific examples.

[0074] The negative electrode material may contain one organic shrinkage inhibitor or a combination of two or more organic shrinkage inhibitors.

[0075] The content of the organic shrinkage inhibitor in the negative electrode material is, for example, 0.01% by mass or more, and may be, for example, 1% by mass or less, or 0.5% by mass or less.

[0076] (Barium Sulfate) The content of barium sulfate in the negative electrode material is, for example, 0.05% by mass or more, or may be 0.1% by mass or more, and the content of barium sulfate is, for example, 3% by mass or less.

[0077] (Specific surface area Sn of negative electrode material) The specific surface area Sn of the negative electrode material is, for example, 0.3 m ２ From the viewpoint of easily ensuring higher charge acceptance, the specific surface area Sn is 0.5 m ２ / g or more is preferable, and 0.8m ２ The specific surface area Sn is, for example, 4 m ２ From the viewpoint of further enhancing the effect of suppressing the amount of electricity in overcharge, the specific surface area Sn is 2.7 m ２ / g or less is preferable, and 2.5m ２ From the viewpoint of further enhancing the effect of suppressing outflow of the first carbonaceous material, the specific surface area Sn is preferably 1 m ２ / g or less is preferable, and 0.88m ２The specific surface area Sn of the negative electrode material can be adjusted, for example, by adjusting the specific surface area and / or content of the components of the negative electrode material (particularly, the first carbonaceous material).

[0078] The specific surface area Sn of the negative electrode material is 0.3 m ２ / g or more (or 0.5m ２ / g or more) 4m ２ / g or less, 0.3m ２ / g or more (or 0.5m ２ / g or more) 2.7m ２ / g or less, 0.3m ２ / g or more (or 0.5m ２ / g or more) 2.5m ２ / g or less, 0.3m ２ / g or more (or 0.5m ２ / g or more) 1m ２ / g or less, 0.3m ２ / g or more (or 0.5m ２ / g or more) 0.88m ２ / g or less, 0.8m ２ / g or more 4m ２ / g or less (or 2.7m ２ / g or less), 0.8m ２ / g or more 2.5m ２ / g or less (or 1m ２ / g or less), or 0.8m ２ / g or more 0.88m ２ / g or less.

[0079] (Analysis or Measurement of Negative Electrode Material) The following describes a method for analyzing a negative electrode material or its constituent components. Prior to measurement or analysis, a fully charged lead-acid battery is disassembled to obtain a negative electrode plate to be analyzed. The obtained negative electrode plate is washed with water to remove sulfuric acid from the negative electrode plate. The washing is continued until a pH test paper is pressed against the washed surface of the negative electrode plate and no color change is confirmed. However, the washing time is limited to within two hours. The washed negative electrode plate is dried in a reduced pressure environment at 60±5°C for approximately six hours. If the negative electrode plate contains an adhesive material, the adhesive material is removed as necessary. Next, a sample (hereinafter referred to as sample A) is obtained by separating the negative electrode material from the negative electrode plate. Sample A is crushed as necessary and subjected to analysis.

[0080] (1) Measurement of Specific Surface Area Sn of Negative Electrode Material The BET specific surface area Sn of the negative electrode material is evaluated by the following procedure. First, a fully charged lead-acid battery is disassembled to remove the negative electrode plate. Next, the negative electrode plate is washed with water to remove sulfuric acid from the negative electrode plate, and then the negative electrode plate is dried. The negative electrode material is collected from the dried negative electrode plate. The collected negative electrode material is pretreated by heating at 150°C for 1 hour in a nitrogen flow. The BET specific surface area of ​​the pretreated material is determined by mass measurement, measurement by gas adsorption method, and calculation using the BET equation. Specifically, the BET specific surface area is determined by measurement using the following apparatus and conditions and calculation using the following calculation method. Measuring device: TriStar 3000 manufactured by Micromeritics Adsorption gas: nitrogen gas with a purity of 99.99% or more Adsorption temperature: boiling point of liquid nitrogen (77K) Calculation method for BET specific surface area: in accordance with 7.2 of JIS Z 8830:2013

[0081] (2) Analysis of Fatty Acids (2-1) Qualitative Analysis of Fatty Acids Pulverized sample A is used. 150.0±0.1 mL of chloroform is added to 100.0±0.1 g of sample A, and the mixture is stirred at 20±5°C for 16 hours to extract the fatty acids. The solids are then removed by filtration. The structure of the fatty acids is identified by obtaining information from at least one of infrared spectroscopy, ultraviolet-visible absorption spectroscopy, NMR spectroscopy, LC-MS, and pyrolysis GC-MS for the chloroform solution containing the fatty acids obtained by extraction, or the fatty acids obtained by drying this chloroform solution.

[0082] (2-2) Quantitative Analysis of Fatty Acids The amount of fatty acid obtained by drying the chloroform solution was measured with an accuracy of ±0.0001 g. ｒ (g) Dissolve in deuterated chloroform together with tetrachloroethane (TCE), １ The H-NMR spectrum is measured. The integral value (S ａ ) and the integral value of the peak due to TCE (S ｒ ) and the mass-based content C of fatty acids in the negative electrode material was calculated from the following formula: ｎ (ppm) is calculated.

[0083] C ｎ = S ａ / S ｒ ×N ｒ / N ａ ×M ａ / M ｒ ×m ｒ / m×1000000 (in the formula, M ａ is the molecular weight of the structure showing a peak at 2.34 ppm in the chemical shift (more specifically, the molecular weight showing the structure of a fatty acid in the chemical shift), and N ａ is the number of hydrogen atoms attached to the carbon atoms of the main chain. ｒ、 M ｒ are the number of hydrogen atoms contained in the molecule of the reference material, the molecular weight of the reference material, and m (g) is the mass of the negative electrode material used for extraction. Note that the reference material in this analysis is TCE (trichloroethylene), so N ｒ = 2, M ｒ= 168. Also, m = 100. For example, if the fatty acid is oleic acid, M ａ is 59, and N ａ is 2.

[0084] １ The H-NMR spectrum is measured under the following conditions: Apparatus: AL400 nuclear magnetic resonance apparatus manufactured by JEOL Ltd. Observation frequency: 395.88 MHz Pulse width: 6.30 μs Pulse repetition time: 74.1411 seconds Number of accumulations: 32 Measurement temperature: room temperature (20° C. or higher and 35° C. or lower) Reference: 7.24 ppm Sample tube diameter: 5 mm

[0085] In quantitative analysis, １ The integral value of the peak in the H-NMR spectrum is determined using data processing software "ALICE" manufactured by JEOL Ltd.

[0086] (3) Analysis of Carbonaceous Materials (3-1) Separation and Quantification of Carbonaceous Materials Pulverized sample A is used. 30 mL of a 60% by mass aqueous nitric acid solution is added per 5 g of sample A and heated at 70°C ± 5°C. Furthermore, 10 g of disodium ethylenediaminetetraacetate, 30 mL of a 28% by mass aqueous ammonia solution, and 100 mL of water are added per 5 g of sample A, and heating is continued to dissolve the soluble components. The sample thus pretreated is recovered by filtration. The recovered sample is passed through a 500 μm sieve to remove large components such as reinforcing materials, and the components that pass through the sieve are recovered as carbonaceous materials.

[0087] Next, the first carbonaceous material and the second carbonaceous material are separated by the following procedure. When the recovered carbonaceous material is wet sieved using a sieve with 32 μm mesh, the material that does not pass through the sieve and remains on the sieve is the second carbonaceous material, and the material that passes through the sieve is the first carbonaceous material. In other words, the particle size of each carbonaceous material is based on the size of the sieve mesh. For wet sieving, JIS Z8815:1994 can be referenced.

[0088] ​Specifically, the carbonaceous material is placed on a sieve with 32 μm mesh size, and sieved by gently shaking the sieve for 5 minutes while spraying ion-exchanged water. The second carbonaceous material remaining on the sieve is recovered from the sieve by pouring ion-exchanged water over it, and separated from the ion-exchanged water by filtration. The first carbonaceous material that passed through the sieve is recovered by filtration using a nitrocellulose membrane filter (0.1 μm mesh size). The recovered first carbonaceous material and second carbonaceous material are each dried at a temperature of 100°C ± 5°C for 2 hours. The 32 μm mesh size sieve used is one equipped with a sieve mesh with a nominal mesh size of 32 μm, as specified in JIS Z 8801-1:2019.

[0089] The proportion of the first carbonaceous material in the entire carbonaceous material is determined by calculating the ratio (mass %) of the measured mass of the first carbonaceous material to the mass of the carbonaceous material (the sum of the masses of each carbonaceous material).

[0090] (3-2) Specific Surface Area Sc of First Carbonaceous Material The BET specific surface area Sc of the first carbonaceous material is determined by a gas adsorption method using the first carbonaceous material separated by the procedure in (3-1) above, using the BET equation. The first carbonaceous material is pretreated by heating at 150°C for 1 hour in a nitrogen flow to remove moisture. The BET specific surface area of ​​the pretreated first carbonaceous material is determined in the same manner as in the case of the specific surface area Sn of the negative electrode material in (1) above.

[0091] (3-3) DBP Oil Absorption Y of First Carbonaceous Material The DBP oil absorption Y of the first carbonaceous material is measured using an absorptometer in accordance with JIS K 6217-4:2017, using the first carbonaceous material separated by the procedure described above in (3-1). More specifically, a certain amount of carbonaceous material is placed in the mixing chamber of the absorptometer, and the rotor is rotated at 125 rpm while dibutyl phthalate (DBP) is dripped from an automatic burette at 4 ml / min. As the kneading progresses over time, the powder in the mixing chamber transitions to a paste state, creating resistance to the rotor rotation. At a certain point, the torque rises sharply with increasing amounts of DBP added, forming a curve that then declines again. The point on the descending curve where the torque reaches 70% of its maximum value is defined as the endpoint, and the amount of DBP used is used as the adsorption value. An S410E absorptometer manufactured by Asahi Research Institute, Ltd. is used as the absorptometer. The measurement is carried out by taking care not to introduce air bubbles into the DBP when the DBP is placed in the automatic burette of the absorptometer.

[0092] (4) Quantitative determination of organic shrink-preventing agent The crushed sample A is immersed in a 1 mol / L aqueous NaOH solution to extract the organic shrink-preventing agent. Insoluble components are removed by filtration from the aqueous NaOH solution containing the extracted organic shrink-preventing agent, and the filtrate (hereinafter also referred to as filtrate C) is recovered.

[0093] A predetermined amount of filtrate C is measured, desalted, concentrated, and dried to obtain a powder of the organic shrink-preventing agent (hereinafter also referred to as sample D). Desalting can be carried out using a desalting column, by passing filtrate C through an ion exchange membrane, or by placing filtrate C in a dialysis tube and immersing it in distilled water.

[0094] The organic shrinkage preventer is identified by combining information obtained from the infrared spectrum of sample D, the ultraviolet-visible absorption spectrum of a solution obtained by dissolving sample D in distilled water or the like, the NMR spectrum of a solution obtained by dissolving sample D in a solvent such as heavy water, or information obtained from pyrolysis GC-MS or the like that can provide information on the individual compounds that make up the substance.

[0095] The ultraviolet-visible absorption spectrum of the filtrate C is measured. The content of the organic shrink-preventing agent in the negative electrode material is quantified from the spectral intensity, the calibration curve prepared in advance, the measured amount of filtrate C, and the mass of sample A. If the structural formula of the organic shrink-preventing agent to be analyzed cannot be precisely identified and a calibration curve for the same organic shrink-preventing agent cannot be used, a calibration curve is prepared using an available organic shrink-preventing agent that exhibits an ultraviolet-visible absorption spectrum, infrared spectrum, NMR spectrum, etc. similar to those of the organic shrink-preventing agent to be analyzed.

[0096] (5) Quantitative Determination of Barium Sulfate: 10 g of pulverized sample A was mixed with 50 ml of 20% by mass nitric acid and heated for approximately 20 minutes to dissolve the lead components as lead ions. The resulting solution was filtered to separate out the carbonaceous material, barium sulfate, and other solids.

[0097] The obtained solid content is dispersed in water to form a dispersion, and then components other than the carbonaceous material and barium sulfate (e.g., reinforcing material) are removed from the dispersion using a sieve. Next, the dispersion is subjected to suction filtration using a membrane filter whose mass has been measured in advance, and the membrane filter together with the filtered sample is dried in a dryer at 110°C ± 5°C. The filtered sample is a mixed sample of the carbonaceous material and barium sulfate. The mass of the membrane filter is subtracted from the total mass of the dried mixed sample (hereinafter referred to as Sample E) and the membrane filter to determine the mass of Sample E (M ｍ ) is measured. Then, Sample E is placed in a crucible together with the membrane filter and burnt at 1300°C or higher for ashing. The remaining residue is barium oxide. The mass of barium oxide is converted to the mass of barium sulfate to determine the mass of barium sulfate (M Ｂ ) is required.

[0098] (Other) The negative electrode material may contain a fatty acid other than the first fatty acid (hereinafter referred to as the second fatty acid). The second fatty acid may be at least one selected from the group consisting of fatty acids having 7 or less carbon atoms and fatty acids having more than 30 carbon atoms. From the viewpoint of obtaining a higher carbonaceous material outflow suppression effect and ensuring higher charge acceptance, a lower content of the second fatty acid is preferable. The content of the second fatty acid in the negative electrode material is, for example, 10 ppm or less, and may even be 5 ppm or less. It is also preferable that the negative electrode material does not contain the second fatty acid. This case also includes cases where the second fatty acid in the negative electrode material is below the detection limit.

[0099] The unformed negative electrode plate is produced, for example, by applying or filling a negative electrode paste onto a negative electrode current collector, followed by aging and drying. More specifically, the negative electrode paste used to produce the unformed negative electrode plate is prepared, for example, by adding water and sulfuric acid (or an aqueous sulfuric acid solution) to lead powder, a carbonaceous material, a first fatty acid, and, if necessary, various additives (such as an organic shrinkage inhibitor or barium sulfate), and kneading the mixture. When aging, it is preferable to age the unformed negative electrode plate at a temperature higher than room temperature and at high humidity. The negative electrode plate is produced, for example, by chemically converting the unformed negative electrode plate.

[0100] The formation can be carried out, for example, by placing a plate assembly including unformed negative plates and an electrolyte containing sulfuric acid in a lead-acid battery container, and charging the plate assembly while the electrolyte is permeated into the plate assembly. However, the formation can also be carried out before assembling the lead-acid battery or the plate assembly. The formation produces spongy lead.

[0101] (Positive Electrode Plate) Positive electrode plates for lead-acid batteries are classified into paste type, clad type, etc. Either the paste type or clad type positive electrode plate may be used.

[0102] The positive electrode current collector may be formed by casting lead (Pb) or a lead alloy, or by processing a lead sheet or a lead alloy sheet. Examples of processing methods include expanding and punching. A lattice-shaped current collector is preferably used as the positive electrode current collector because it is easy to support the positive electrode material.

[0103] As the lead alloy used for the positive electrode current collector, a Pb—Sb-based alloy, a Pb—Ca-based alloy, or a Pb—Ca—Sn (tin)-based alloy is preferred in terms of corrosion resistance and mechanical strength. The positive electrode current collector may have a surface layer. The surface layer and the inner layer of the positive electrode current collector may have different compositions. The surface layer may be formed so as to cover the entire positive electrode current collector, or may be formed on only a part of the positive electrode current collector. The surface layer may be formed only on the grid portion, the lug portion, or the frame portion of the positive electrode current collector.

[0104] The positive electrode material contains a positive electrode active material (lead dioxide or lead sulfate) that generates capacity through an oxidation-reduction reaction. The positive electrode material may contain other additives as needed.

[0105] Unformed paste-type positive electrode plates are obtained by filling a positive electrode current collector with a positive electrode paste, aging it, and drying it. The positive electrode paste is prepared by kneading lead powder, additives, water, and sulfuric acid. Unformed clad-type positive electrode plates are formed by filling porous tubes with lead powder or lead powder slurry, into which core metals connected by current collectors are inserted, and then joining multiple tubes together. These unformed positive electrode plates are then chemically formed to obtain positive electrode plates.

[0106] The formation may be performed by immersing an electrode plate assembly including unformed positive electrode plates in an electrolyte containing sulfuric acid in a battery container of the lead-acid battery and then charging the electrode plate assembly, but the formation may also be performed before assembling the lead-acid battery or the electrode plate assembly.

[0107] (Separator) A separator may be disposed between the negative electrode plate and the positive electrode plate. As the separator, at least one material selected from a nonwoven fabric and a microporous membrane is used.

[0108] A nonwoven fabric is a mat of intertwined fibers, primarily composed of fibers. For example, 60% by mass or more of the nonwoven fabric is made of fibers. Examples of fibers that can be used include glass fibers, polymer fibers (polyolefin fibers, acrylic fibers, polyester fibers (e.g., polyethylene terephthalate fibers), pulp fibers, and the like. Among these, glass fibers are preferred. The nonwoven fabric may also contain components other than fibers (e.g., acid-resistant inorganic powder, polymers as binders, etc.).

[0109] On the other hand, a microporous membrane is a porous sheet mainly composed of components other than fiber components, and can be obtained, for example, by extruding a composition containing a pore-forming agent into a sheet and then removing the pore-forming agent to form pores. The microporous membrane is preferably made of an acid-resistant material, and a microporous membrane mainly composed of a polymer component is preferred. The polymer component is preferably polyolefin (polyethylene, polypropylene, etc.). The pore-forming agent can be at least one selected from the group consisting of polymer powder and oil.

[0110] The separator may be made of, for example, only a nonwoven fabric or only a microporous membrane. Furthermore, the separator may be a laminate of a nonwoven fabric and a microporous membrane, a laminate of different or the same materials, or a laminate of different or the same materials with recesses and protrusions interlocked, as needed.

[0111] The separator may be sheet-shaped or bag-shaped. A single sheet-shaped separator may be sandwiched between the positive electrode plate and the negative electrode plate. Alternatively, the electrode plates may be sandwiched between a single folded sheet-shaped separator. In this case, a positive electrode plate sandwiched between folded sheet-shaped separators may be stacked on top of a negative electrode plate sandwiched between folded sheet-shaped separators, or one of the positive electrode plate and the negative electrode plate may be sandwiched between folded sheet-shaped separators and stacked on top of the other electrode plate. Alternatively, a sheet-shaped separator may be folded into an accordion shape, and the positive electrode plate and the negative electrode plate may be sandwiched between the accordion-shaped separators so that the separator is interposed between them. When using a separator folded like an accordion, the separator may be arranged so that the folded portions are aligned with the horizontal direction of the lead-acid battery (e.g., so that the folded portions are parallel to the horizontal direction) or so that the folded portions are aligned with the vertical direction (e.g., so that the folded portions are parallel to the vertical direction). In a separator folded like an accordion, recesses are formed alternately on both main surfaces of the separator. Because the positive and negative plates usually have lugs on the top, when the separator is arranged so that the folded portions are aligned with the horizontal direction of the lead-acid battery, the positive and negative plates are positioned in the recesses on only one main surface of the separator (i.e., a double separator is interposed between adjacent positive and negative plates). When the separator is arranged so that the folded portion is aligned with the vertical direction of the lead-acid battery, the positive electrode plate may be accommodated in the recess on one main surface side, and the negative electrode plate may be accommodated in the recess on the other main surface side (that is, a single separator may be interposed between adjacent positive and negative electrode plates).When a pouch-shaped separator is used, the pouch-shaped separator may accommodate either the positive electrode plate or the negative electrode plate.

[0112] (Electrolyte) The electrolyte is an aqueous solution containing sulfuric acid, and may be gelled as necessary.

[0113] The electrolytic solution may contain cations (e.g., metal cations) and / or anions (e.g., anions other than sulfate anions (e.g., phosphate ions)) as needed. Examples of metal cations include at least one selected from the group consisting of Na ions, Li ions, Mg ions, and Al ions.

[0114] The density of the electrolyte in a fully charged lead acid battery at 20°C is, for example, 1.20 g / cm ３ or more, and 1.25 g / cm ３ The density of the electrolyte at 20°C may be 1.35 g / cm or more. ３ or less, and 1.32 g / cm ３ It is preferable that:

[0115] The density of the electrolyte at 20 ° C. is 1.20 g / cm ３ 1.35g / cm or more ３ Below, 1.20g / cm ３ 1.32g / cm or more ３ Below, 1.25g / cm ３ 1.35g / cm or more ３ or less, or 1.25 g / cm ３ 1.32g / cm or more ３ It may be the following:

[0116] (Other) A lead-acid battery includes at least one electrode plate group and an electrolyte. The lead-acid battery may include one cell or two or more cells. When the lead-acid battery includes multiple cells (i.e., multiple electrode plate groups), the multiple electrode plate groups may be connected in series.

[0117] The lead-acid battery may be obtained, for example, by a manufacturing method including a step of housing a plate assembly and an electrolyte in a battery case (or in a cell chamber of the battery case). Each cell of the lead-acid battery includes a plate assembly and an electrolyte housed in each cell chamber. The plate assembly is assembled by stacking positive electrode plates, negative electrode plates, and a separator with the separator interposed between the positive electrode plates and the negative electrode plates prior to housing in the battery case or cell chamber. The positive electrode plates, negative electrode plates, electrolyte, and separator are each prepared prior to assembling the plate assembly. The manufacturing method of the lead-acid battery may include a step of chemically converting at least one of the positive electrode plates and the negative electrode plates, as necessary, after the step of housing the plate assembly and the electrolyte in the battery case or cell chamber.

[0118] (Evaluation) The leakage of the first carbonaceous material into the electrolyte, charge acceptance, overcharge electricity quantity, and PSOC life performance are evaluated according to the following procedures (a) to (d). For the evaluation, a test battery having a nominal voltage of 2 V and a rated 5-hour rate capacity of 32 Ah is used.

[0119] (a) Leakage of First Carbonaceous Material into Electrolyte A plurality of standard solutions with different concentrations are prepared by dispersing a carbonaceous material in the electrolyte at a concentration ranging from 1 ppm to 300 ppm by mass. The turbidity of a sample of electrolyte removed from a fully charged lead-acid battery is visually compared with that of the standard sample solution, and the concentration of the carbonaceous material in the standard sample solution with the closest turbidity is determined to be the concentration of the first carbonaceous material in the sample. Based on this concentration, the leakage of the first carbonaceous material into the electrolyte is evaluated. When the concentration of the carbonaceous material in the electrolyte is 3 ppm or less by mass, a marker for visually checking the liquid level in the lead-acid battery can be clearly seen, but when the concentration exceeds 3 ppm, the marker becomes difficult to see.

[0120] (b) Charge Acceptance: Using a fully charged test battery, the quantity of electricity at 10 seconds is measured. Specifically, the test battery is discharged at 6.4 A for 30 minutes and left to stand for 16 hours. The test battery is then charged at a constant current and constant voltage of 2.42 V / cell with a maximum current of 200 A, and the cumulative quantity of electricity over 10 seconds (quantity of electricity at 10 seconds) is measured. Both procedures are performed in a water tank at 25°C ± 2°C. The cumulative quantity of electricity over 10 seconds is used as an index for evaluating charge acceptance.

[0121] (c) Overcharge Quantity of Electricity The overcharge quantity of electricity is evaluated using the above test battery in a fully charged state according to the following procedure. Specifically, the fully charged test battery is charged at a constant voltage of 2.4 V / cell for 168 hours in a water bath at a temperature of 60±3°C. The charging current (A) during this constant voltage charging is multiplied by the charging time (h) to determine the integrated value (Ah) of the overcharge quantity of electricity. The overcharge quantity of electricity is evaluated based on this integrated value.

[0122] (d) PSOC Life Performance The above test battery was charged and discharged in an air tank at 40°C ± 3°C according to the pattern shown in Table 1. The number of cycles from step 1 to step 10 until the terminal voltage of the test battery reached 1.2 V per cell was used as an index of PSOC cycle life performance. In this specification, 1 CA is the current value (A) that is the same as the nominal capacity (Ah) of the battery. For example, for a battery with a nominal capacity of 30 Ah, 1 CA is 30 A, and 1 mCA is 30 mA.

[0123]

[0124] The elements described herein may be combined in any manner.

[0125] The lead-acid batteries according to the first and second aspects of the present invention will be collectively described below.

[0126] (1) A lead-acid battery, the lead-acid battery including a plate assembly and an electrolyte, the plate assembly including positive plates including a positive electrode material, negative plates including a negative electrode material, and a separator interposed between the positive electrode plates and the negative electrode plates, the negative electrode material including a first carbonaceous material having a particle diameter of less than 32 μm and a fatty acid (first fatty acid) having a carbon number of 8 to 30, a content Cc1 of the first carbonaceous material in the negative electrode material being 0.4 mass% or more, a mass-based content Cf (ppm) of the fatty acid in the negative electrode material being 0.5 mass% or more, and a specific surface area Sn (m ２ / g), the ratio of the content Cf to the specific surface area Sn: Cf / Sn is 20 ppm m －２ g or more.

[0127] (2) In the above (1), the Cf / Sn is 1000 ppm m－２ g or less, or 910 ppm m －２ ・It may be less than g.

[0128] (3) In the above (1) or (2), the Cf / Sn is 23 ppm m －２ ・It may be g or more.

[0129] (4) In any one of (1) to (3) above, when the DBP oil absorption of the first carbonaceous material is Y, the ratio of the content Cf to the DBP oil absorption Y: Cf / Y is 0.1 ppm mL －１ ・It may be 100g or more.

[0130] (5) A lead-acid battery, comprising: a plate assembly and an electrolyte; the plate assembly comprising positive plates including a positive electrode material, negative plates including a negative electrode material, and a separator interposed between the positive electrode plates and the negative electrode plates; the negative electrode material comprising a first carbonaceous material having a particle size of less than 32 μm and a fatty acid (first fatty acid) having 8 to 30 carbon atoms; a content Cc1 of the first carbonaceous material in the negative electrode material being 0.4 mass% or more; and a ratio Cf / Y of the content Cf to the DBP oil absorption Y being 0.1 ppm mL, where Cf (ppm) is the mass-based content of the fatty acid in the negative electrode material and Y is the DBP oil absorption of the first carbonaceous material. －１ - Lead-acid batteries weighing 100g or more.

[0131] (6) In the above (4) or (5), the Cf / Y is 12 ppm mL －１ ・Less than 100g, 9.5ppm・mL －１ ・Less than 100g, 5ppm・mL －１ ・100g or less or 3.5 ppm mL －１ ・It may be less than 100g.

[0132] (7) In any one of the above (4) to (6), the Cf / Y is 0.12 ppm mL －１ ・It may be 100g or more.

[0133] (8) In any one of the above (4) to (7), the DBP oil absorption Y may be 30 mL / 100 g or more, 50 mL / 100 g or more, or 65 mL / 100 g or more.

[0134] (9) In any one of the above (4) to (8), the DBP oil absorption Y may be 600 mL / 100 g or less, 500 mL / 100 g or less, 400 mL / 100 g or less, 360 mL / 100 g or less, or 200 mL / 100 g or less.

[0135] (10) In any one of (1) to (9) above, the content Cf of the first fatty acid may be 15 ppm or more, 20 ppm or more, or 50 ppm or more by mass.

[0136] (11) In any one of the above (1) to (10), the content Cf of the first fatty acid may be 1000 ppm or less, or 600 ppm or less, by mass.

[0137] (12) In any one of (1) to (11) above, the content Cc1 of the first carbonaceous material may be 5 mass % or less, 3 mass % or less, or 2 mass % or less.

[0138] (13) In any one of (1) to (12) above, the content Cc1 of the first carbonaceous material may be 0.5 mass % or more.

[0139] (14) In any one of the above (1) to (13), the first carbonaceous material may include carbon black.

[0140] (15) In any one of the above (1) to (14), the negative electrode material may further include a second carbonaceous material having a particle diameter of 32 μm or more.

[0141] (16) In the above (15), the second carbonaceous material may include graphite.

[0142] (17) In the above (15) or (16), the proportion of the first carbonaceous material (such as carbon black) in the entire carbonaceous material (the total amount of the first carbonaceous material and the second carbonaceous material) may be 50% by mass or more, 75% by mass or more, 80% by mass or more, or 90% by mass or more.

[0143] (18) In any one of (15) to (17) above, the proportion of the first carbonaceous material (such as carbon black) in the entire carbonaceous material (the total amount of the first carbonaceous material and the second carbonaceous material) may be 100% by mass or less, or 95% by mass or less.

[0144] (19) In any one of (1) to (18) above, the specific surface area Sc of the first carbonaceous material is 20 m ２ / g or more, 25m ２ / g or more, or 28m ２ / g or more.

[0145] (20) In any one of (1) to (19) above, the specific surface area Sc of the first carbonaceous material is 1500 m ２ / g or less, 1300m ２ / g or less, 800m ２ / g or less, 200m ２ / g or less, or 150m ２ / g or less.

[0146] (21) In any one of (1) to (20) above, the first fatty acid may have 9 or more carbon atoms.

[0147] (22) In any one of (1) to (21) above, the number of carbon atoms of the first fatty acid may be 24 or less, or 20 or less.

[0148] (23) In any one of the above (1) to (22), the first fatty acid may have a carbon-carbon unsaturated bond.

[0149] (24) In the above (23), the number of carbon-carbon unsaturated bonds contained in the first fatty acid may be 6 or less, 4 or less, or 2 or less.

[0150] (25) In the above (23) or (24), the number of carbon-carbon unsaturated bonds contained in the first fatty acid may be one or more.

[0151] (26) In any one of the above (1) to (25), the specific surface area Sn of the negative electrode material is 0.3 m ２ / g or more, 0.5m ２ / g or more, or 0.8m ２ / g or more.

[0152] (27) In any one of the above (1) to (26), the specific surface area Sn of the negative electrode material is 4 m ２ / g or less, 2.7m ２ / g or less, 2.5m ２ / g or less, 1m ２ / g or less, or 0.88m ２ / g or less.

[0153] (28) In any one of the above (1) to (27), the negative electrode material may contain an organic shrinkage preventer.

[0154] (29) In the above (28), the content of the organic shrinkage preventer in the negative electrode material may be 0.01% by mass or more.

[0155] (30) In the above (28) or (29), the content of the organic shrinkage preventer in the negative electrode material may be 1% by mass or less or 0.5% by mass or less.

[0156] (31) In any one of the above (1) to (30), the negative electrode material may contain barium sulfate.

[0157] (32) In the above (31), the content of the barium sulfate in the negative electrode material may be 0.05% by mass or more, or 0.1% by mass or more.

[0158] (33) In the above (31) or (32), the content of the barium sulfate in the negative electrode material may be 3 mass % or less.

[0159] (34) In any one of the above (1) to (33), the negative electrode material may contain a second fatty acid other than the first fatty acid.

[0160] (35) In the above (34), the second fatty acid may include at least one selected from the group consisting of fatty acids having 7 or less carbon atoms and fatty acids having more than 30 carbon atoms.

[0161] (36) In the above (34) or (35), the content of the second fatty acid in the negative electrode material may be 10 ppm or less, or 5 ppm or less.

[0162] (37) In any one of (1) to (36) above, the density of the electrolyte in the lead acid battery in a fully charged state at 20 ° C. is 1.20 g / cm ３ or more, or 1.25 g / cm ３ It may be more than that.

[0163] (38) In any one of (1) to (37) above, the density of the electrolyte in the fully charged lead-acid battery at 20 ° C. is 1.35 g / cm ３ or less, or 1.32 g / cm ３ It may be the following:

[0164] FIG. 1 shows the external appearance of an example of a lead-acid battery according to one embodiment of the present invention. The lead-acid battery 1 includes a battery case 12 that contains a plate pack 11 and an electrolyte (not shown). The battery case 12 is divided into multiple cell chambers 14 by partition walls 13. Each cell chamber 14 contains one plate pack 11. The opening of the battery case 12 is closed with a lid 15 that includes a negative electrode terminal 16 and a positive electrode terminal 17. The lid 15 is provided with a vent plug 18 for each cell chamber. When rehydrating, the vent plug 18 is removed and rehydration solution is added. The vent plug 18 may have a function of venting gas generated in the cell chamber 14 to the outside of the battery.

[0165] Each electrode plate group 11 is formed by stacking a plurality of negative electrode plates 2 and positive electrode plates 3 with separators 4 interposed therebetween. Here, a bag-shaped separator 4 is shown housing the negative electrode plates 2, but the shape of the separator is not particularly limited. In a cell chamber 14 located at one end of the battery case 12, a negative electrode shelf 6 that connects a plurality of negative electrode plates 2 in parallel is connected to a through-connector 8, and a positive electrode shelf 5 that connects a plurality of positive electrode plates 3 in parallel is connected to a positive electrode pole 7. The positive electrode pole 7 is connected to a positive electrode terminal 17 outside the lid 15. In a cell chamber 14 located at the other end of the battery case 12, a negative electrode pole 9 is connected to the negative electrode shelf 6, and a through-connector 8 is connected to the positive electrode shelf 5. The negative electrode pole 9 is connected to a negative electrode terminal 16 outside the lid 15. Each through-connector 8 passes through a through-hole provided in the partition wall 13 to connect the electrode plate groups 11 of adjacent cell chambers 14 in series.

[0166] The positive electrode shelf 5 is formed by welding together the lugs provided on the top of each positive electrode plate 3. The negative electrode shelf 6 is also formed by welding together the lugs provided on the top of each negative electrode plate 2.

[0167] The lid 15 of the lead-acid battery has a single structure (single lid), but this is not limited to the illustrated example. The lid 15 may have a double structure including, for example, an inner lid and an outer lid (or top lid). A lid having a double structure may have a reflux structure between the inner lid and the outer lid for returning the electrolyte to the battery (inside the inner lid) from a reflux port provided in the inner lid.

[0168] EXAMPLES The present invention will be specifically described below based on examples and comparative examples, but the present invention is not limited to the following examples.

[0169] Lead-Acid Batteries E1-E14, C1-C5, and R1 (1) Preparation of Lead-Acid Batteries (a) Preparation of Negative Electrode Plates Lead powder, a carbonaceous material, a fatty acid or other additive listed in Table 2 or Table 3, an organic shrinkage preventer (sodium lignosulfonate), and barium sulfate were mixed with an appropriate amount of aqueous sulfuric acid solution to obtain a negative electrode paste. The components were mixed so that the carbonaceous material content Cc and the fatty acid content Cf in the negative electrode material, both of which were determined by the procedures described above, were the values ​​shown in Table 2 or Table 3. Furthermore, these components were mixed so that the organic shrinkage preventer content was 0.1% by mass and the barium sulfate content was 0.4% by mass. Another additive, polypropylene glycol (PPG), was blended so that its content in the dry solids of the mixture was 20 ppm, as shown in Table 2 or Table 3. The negative electrode paste was filled into the mesh of a Pb-Ca-Sn alloy expanded grid, and then aged and dried to obtain an unformed negative electrode plate. The carbonaceous material used was carbon black, the specific surface area Sc and DBP oil absorption Y of which were determined by the previously described procedures and exhibited the values ​​shown in Tables 2 and 3.

[0170] (b) Preparation of Positive Electrode Plate: Lead powder as raw material was mixed with sulfuric acid solution to obtain a positive electrode paste. The positive electrode paste was filled into the mesh portion of a Pb—Ca—Sn alloy expanded grid, and then aged and dried to obtain an unformed positive electrode plate.

[0171] (c) Preparation of Test Battery The test battery had a rated voltage of 2 V and a rated 5-hour rate capacity of 32 Ah. The electrode plate assembly of the test battery consisted of seven positive electrode plates and seven negative electrode plates. The negative electrode plates were housed in a pouch-shaped separator made of a polyethylene microporous film and alternately stacked with the positive electrode plates to form an electrode plate assembly. The electrode plate assembly was housed in a polypropylene battery case together with an electrolyte (aqueous sulfuric acid solution) and subjected to chemical formation in the battery case to prepare a liquid lead-acid battery. After chemical formation, the lead-acid battery was almost fully charged. The density of the electrolyte in the fully charged lead-acid battery at 20°C was 1.28 g / cm ３ It was.

[0172] (2) Evaluation The produced lead-acid batteries (test batteries) were evaluated in the following ways (a) to (d).

[0173] (a) Outflow of carbonaceous material into electrolyte The degree of outflow of carbonaceous material into the electrolyte (concentration of carbonaceous material in the electrolyte) was determined using the procedure described above. When the concentration of the carbonaceous material in the electrolyte was 3 ppm or less by mass, it was determined that a high effect of suppressing outflow of the carbonaceous material was obtained.

[0174] (b) Charge Acceptance The charge acceptance of the test battery was evaluated according to the procedure described above. The charge acceptance of the test battery of each example was expressed as a percentage, assuming that the cumulative amount of electricity for 10 seconds of the test battery of Comparative Example 1 was 100%.

[0175] (c) Overcharge Quantity of Electricity The overcharge quantity of the test battery was evaluated according to the procedure described above. The overcharge quantity of the test battery of each example was expressed as a percentage when the integrated value of the overcharge quantity of electric energy of the test battery of Comparative Example 1 was set to 100%.

[0176] (d) Specific Surface Area Sn of Negative Electrode Material The specific surface area Sn was calculated using the negative electrode material sampled from the negative electrode plate removed from the test battery according to the procedure described above.

[0177] (e) PSOC Life Performance The PSOC life performance of the test batteries E1, E13, and E14 was evaluated using the procedure described above. The PSOC life performance of each test battery was evaluated as a relative value when the number of cycles for E1 was set to 100. A larger value indicates better PSOC life performance.

[0178] The results are shown in Tables 2 and 3. These tables also show the values ​​of the ratio Cf / Sn and the ratio Cf / Y. E1 to E14 are working examples, C1 to C5 are comparative examples, and R1 is a reference example.

[0179]

[0180] As shown in Table 2, when the content Cc1 of the first carbonaceous material in the negative electrode material was 0.4 mass% or less, there was almost no leakage of the first carbonaceous material into the electrolyte, and the electrolyte was hardly cloudy (R1). However, when the content Cc1 of the first carbonaceous material was greater than 0.4 mass%, leakage of the first carbonaceous material into the electrolyte was significant, at 6 ppm (C1). Note that the specific surface area Sc and DBP oil absorption Y of the first carbonaceous material differ between R1 and C1. However, leakage of the first carbonaceous material was significant in C4, which used a first carbonaceous material exhibiting the same specific surface area Sc and DBP oil absorption Y as R1. From this, it can be said that in lead-acid batteries using an electrolyte not containing a first fatty acid, it does not depend on the specific surface area Sc and DBP oil absorption Y of the first carbonaceous material. In addition, when the content Cc1 of the first carbonaceous material is 0.4 mass % or more, it can be said that a problem occurs in which the outflow of the first carbonaceous material becomes significant (comparison with R1, C1 and C4).

[0181] In addition, the ratio Cf / Sn is 20 ppm m －２ - When the ratio Cf / Y is less than 0.1 ppm mL －１ When the amount was less than 100 g, even when the first fatty acid was used, the effect of suppressing the outflow of the first carbonaceous material into the electrolyte was hardly obtained (C4).

[0182] Ratio Cf / Sn is 20 ppm m －２ g or more or the ratio Cf / Y is 0.1 ppm mL －１ Even when the amount was 100 g or more, when the number of carbon atoms in the fatty acid was less than 8, the effect of suppressing the outflow of the first carbonaceous material into the electrolyte was hardly obtained (C2 and C3). Furthermore, even when PPG was used instead of the fatty acid, the effect of suppressing the outflow of the first carbonaceous material into the electrolyte was hardly obtained (C5).

[0183] In contrast, in E1 to E12, the outflow of the first carbonaceous material was reduced to 3 ppm or less. In addition, the overcharge quantity of electricity was suppressed to a low level while maintaining a relatively high charge acceptance. These batteries used the first fatty acid and had a Cf / Sn ratio of 20 ppm m or more. －２ g or Cf / Y≧0.1 ppm mL －１ -To meet 100g.

[0184] For example, compared to C5 using PPG, E3 achieved a high effect of suppressing the outflow of the first carbonaceous material and ensured higher charge acceptance with the same amount of overcharge electricity. From the viewpoint of further reducing the amount of overcharge electricity, the ratio Cf / Y was set to 0.12 ppm ml －１ - 100g or more is preferred (comparison of E9 with E3 and E5).

[0185]

[0186] As shown in Table 3, when the first carbonaceous material and the second carbonaceous material were used in combination, superior PSOC life performance was obtained (E13 and E14) compared to E1, which used only the first carbonaceous material as the carbonaceous material. Furthermore, in E13 and E14, the overcharge quantity of electricity was kept low to the same extent as in E1, and higher charge acceptance was obtained compared to E1.

[0187] While the present invention has been described in terms of presently preferred embodiments, such disclosure is not to be interpreted as limiting. Various changes and modifications will no doubt become apparent to those skilled in the art to which the present invention pertains upon reading the above disclosure. It is therefore intended that the appended claims be interpreted to cover all changes and modifications that do not depart from the true spirit and scope of the invention.

[0188] The lead-acid batteries according to the first and second aspects of the present invention are suitable for applications including, for example, charging and discharging in a PSOC. Examples of such applications include power supplies for applications in which charging and discharging are controlled by a PSOC. Examples of applications in which charging and discharging are controlled by a PSOC include IS vehicles, charge control applications, and vehicle accessory applications as IS lead-acid batteries. An IS vehicle is an IS-controlled vehicle equipped with an idle reduction system (Idle Reduction System). Idling stop systems are commonly referred to as ISSs. Furthermore, lead-acid batteries can be suitably used as, for example, starting power sources for vehicles (such as automobiles and motorcycles), power sources for vehicle accessories, and industrial power storage devices (such as power sources for electric vehicles (such as forklifts)). These are merely examples, and the applications of lead-acid batteries are not limited to these.

[0189] 1: Lead-acid battery 2: Negative electrode plate 3: Positive electrode plate 4: Separator 5: Positive electrode shelf 6: Negative electrode shelf 7: Positive electrode column 8: Through-connector 9: Negative electrode column 11: Plate group 12: Battery case 13: Partition wall 14: Cell chamber 15: Lid 16: Negative electrode terminal 17: Positive electrode terminal 18: Vent plug

Claims

1. A lead-acid battery, comprising: an electrode plate group and an electrolyte; the electrode plate group comprising: a positive electrode plate including a positive electrode material; a negative electrode plate including a negative electrode material; and a separator interposed between the positive electrode plate and the negative electrode plate; the negative electrode material comprising: a first carbonaceous material having a particle size of less than 32 μm; and a fatty acid having a carbon number of 8 to 30; a content Cc1 of the first carbonaceous material in the negative electrode material being 0.4 mass% or more; and a ratio Cf / Y of the content Cf to the DBP oil absorption Y being 0.1 ppm mL －１ A lead-acid battery weighing 100g or more.

2. A lead-acid battery, comprising: an electrode plate group and an electrolyte; the electrode plate group comprising: a positive electrode plate including a positive electrode material; a negative electrode plate including a negative electrode material; and a separator interposed between the positive electrode plate and the negative electrode plate; the negative electrode material comprising: a first carbonaceous material having a particle size of less than 32 μm; and a fatty acid having a carbon number of 8 or more and 30 or less; a content Cc1 of the first carbonaceous material in the negative electrode material being 0.4 mass% or more; a mass-based content of the fatty acid in the negative electrode material being Cf (ppm) and a specific surface area of ​​the negative electrode material being Sn (m ２ / g), the ratio of the content Cf to the specific surface area Sn: Cf / Sn is 20 ppm m －２ g or more.

3. The Cf / Sn is 1000 ppm m －２ The lead-acid battery according to claim 2, wherein the resistance is equal to or less than 1.0 g.

4. When the DBP oil absorption of the first carbonaceous material is Y, the ratio of the content Cf to the DBP oil absorption Y: Cf / Y is 0.1 ppm mL －１ The lead-acid battery according to claim 2, having a weight of 100 g or more.

5. The Cf / Y is 12 ppm mL －１ The lead-acid battery according to claim 1 or 4, having a weight of 100 g or less.

6. The Cf / Y is 0.12 ppm mL －１ The lead-acid battery according to claim 1 or 4, having a weight of 100 g or more.

7. The lead-acid battery according to any one of claims 1 to 4, wherein the fatty acid content Cf is equal to or greater than 20 ppm and equal to or less than 600 ppm by mass.

8. A lead-acid battery according to any one of claims 1 to 4, wherein the content Cc1 of the first carbonaceous material is 2 mass% or less.

9. The lead-acid battery according to any one of claims 1 to 4, wherein the first carbonaceous material includes carbon black.

10. The lead-acid battery according to any one of claims 1 to 4, wherein the negative electrode material further comprises a second carbonaceous material having a particle size of 32 µm or more.

11. The lead-acid battery of claim 10, wherein the second carbonaceous material comprises graphite.

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