Valve-regulated lead-acid battery and power storage system including same

Abstract

A control valve type lead acid storage battery which is provided with a plurality of cells and a plurality of cell chambers each containing one of the plurality of cells, wherein: each of the plurality of cells is provided with a positive electrode plate, a negative electrode plate and an electrolyte solution; the plurality of cell chambers are provided with exhaust valves that are independent from each other; the positive electrode plate comprises a positive electrode material; the negative electrode plate comprises a negative electrode material; the negative electrode material contains a carbonaceous material; the specific surface area Sc of the carbonaceous material as determined by a BET method satisfies Sc ≥ 500 m2 / g; and the content Cc of the carbonaceous material in the negative electrode material satisfies Cc ≥ 0.5% by mass.

Description

[Technical Field]

[0001] The present invention relates to a valve-regulated lead-acid battery and an electricity storage system including the same. [Background technology]

[0002] Valve-regulated (sealed) lead-acid batteries are used in a variety of applications, including automotive applications (four-wheeled automobiles, small mobility vehicles (such as motorcycles)), industrial applications, and more. A valve-regulated lead-acid battery includes a negative electrode plate, a positive electrode plate, a separator interposed between the negative and positive electrode plates, and an electrolyte. A nonwoven fabric made of glass fiber or the like is used as the separator. Each of the positive and negative electrode plates includes an electrode material. The negative electrode material includes, in addition to lead, which is the active material, a carbon material, an organic shrinkage inhibitor, and the like.

[0003] Patent Document 1 discloses a BET surface area of ​​150 m 2 / g~2000m 2 / g, and D 90 The present invention proposes a composition for use as a negative electrode active material in a sealed lead-acid battery, which comprises a carbon material having a particle size greater than 5 μm, wherein the amount of the carbon material is in the range of 0.1 wt % to 1.5 wt % based on the total weight of the composition.

[0004] Patent Document 2 teaches a method for manufacturing a sealed lead-acid battery before chemical conversion treatment, in which a plurality of exhaust pipes are disposed in a recessed space formed in the upper surface of the battery lid, the exhaust pipes penetrating the bottom wall and communicating with each of the cell chambers inside the battery case, and each exhaust pipe is provided with a safety valve, and a fitting and locking groove is provided in part of an enclosing wall surrounding the recessed space, and when chemical conversion treatment is performed on this, a temporary cover plate is applied to cover the upper parts of the exhaust pipes provided with the safety valves, and the peripheral parts of the temporary cover plate are fitted and locked into the fitting and locking groove so as to be temporarily fixed to the battery lid, and then the battery is subjected to chemical conversion treatment, and then the temporary cover plate is removed, and then a permanent cover plate is applied to the open upper surface of the recessed space and fixed to the battery lid.

[0005] On the other hand, Patent Document 3 teaches a sealed lead-acid battery in which exhaust gases generated from a plurality of cells are guided into a collective exhaust chamber in the lid and the gases are discharged to the outside from one location in the exhaust chamber, the collective exhaust chamber being formed by a recess formed in the upper surface of the lid and an upper plate covering the upper surface of the recess, the recess having vent holes in the bottom wall above each cell that communicate with each cell, and a partition wall between adjacent vent holes, the partition wall having a notch formed in a position that allows the vent holes to communicate with each other over the longest distance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2015-537345 [Patent Document 2] Japanese Patent Application Publication No. 9-270268 [Patent Document 3] Japanese Patent Application Laid-Open No. 2001-84981 Summary of the Invention [Problem to be solved by the invention]

[0007] Lead-acid batteries are sometimes used in a state of insufficient charge known as a partial state of charge (PSOC). For example, lead-acid batteries installed in vehicles with idle reduction (or start-stop) control are used in PSOC. When a lead-acid battery is used in PSOC, stratification tends to occur, where the electrolyte density gradually decreases in the upper part of the battery and increases in the lower part. As stratification progresses, lead sulfate accumulates significantly in the lower part of the negative electrode plate, making sulfation, in which lead sulfate crystals form, more likely to occur. This reduces capacity and causes uneven charge-discharge reactions, deteriorating the electrode plates and shortening the lifespan of the lead-acid battery. In this specification, idle reduction is sometimes simply referred to as IS. [Means for solving the problem]

[0008] One aspect of the present invention is A valve-regulated lead-acid battery, A plurality of cells and a plurality of cell chambers each containing the plurality of cells, Each of the plurality of cells includes a positive electrode plate, a negative electrode plate, and an electrolyte; The plurality of cell chambers each have an exhaust valve independent of one another, the positive electrode plate comprises a positive electrode material; the negative electrode plate comprises a negative electrode material; the negative electrode material includes a carbonaceous material, The specific surface area of ​​the carbonaceous material by the BET method: Sc is Sc≧500m 2 / g is satisfied, The content Cc of the carbonaceous material in the negative electrode material satisfies Cc≧0.5 mass % in the valve-regulated lead-acid battery.

[0009] Another aspect of the present invention is a valve-regulated lead-acid battery; a vehicle that receives a supply of power from the valve-regulated lead-acid battery; a state of charge control unit that controls the SOC of the valve-regulated lead-acid battery, The valve-regulated lead-acid battery includes a plurality of cells and a plurality of cell chambers that respectively accommodate the plurality of cells, Each of the plurality of cells includes a positive electrode plate, a negative electrode plate, and an electrolyte; The plurality of cell chambers each have an exhaust valve independent of each other, the negative electrode plate comprises a negative electrode material including a carbonaceous material, The specific surface area of ​​the carbonaceous material by the BET method: Sc is Sc≧500m 2 / g is satisfied, the content Cc of the carbonaceous material in the negative electrode material satisfies Cc≧0.5% by mass, The vehicle relates to a power storage system in which idling stop control is performed when the SOC of the valve-regulated lead-acid battery is equal to or greater than a threshold of 90%, and idling stop control is not performed when the SOC of the valve-regulated lead-acid battery is less than the threshold. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view schematically illustrating the structure of an individual cell exhaust-type lead-acid battery according to one embodiment. [Figure 2] 1 is a cross-sectional view schematically illustrating a structure of a bulk exhaust type lead acid battery according to one embodiment. [Figure 3] 1 is a block diagram schematically illustrating a configuration of a power storage system according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] When lead-acid batteries are used in PSOC, stratification progresses, making the negative electrode plate more susceptible to sulfation, resulting in a shortened lifespan of the lead-acid battery. In contrast, if the negative electrode material contains a carbonaceous material and the following conditions (A) and (B) are met, the progression of sulfation is suppressed.

[0013] Condition (A) The specific surface area Sc of the carbonaceous material by the BET method is Sc ≥ 500 m 2 / g Condition (B): The content Cc of the carbonaceous material in the negative electrode material is Cc≧0.5% by mass

[0014] In negative electrode materials that satisfy conditions (A) and (B), the conductive path provided by the carbonaceous material is significantly developed, and the ionic conductivity around the lead is improved, facilitating the reduction of lead sulfate in the negative electrode plate. This allows the charge / discharge reaction in the electrode plate to occur more uniformly, suppressing plate deterioration. This can improve the lifespan of lead-acid batteries.

[0015] When Cc<0.5 mass%, the carbonaceous material cannot form a sufficient conductive path. 2 / g and Sc≧500m 2 / g, the amount of lead sulfate accumulation is almost the same, and there is almost no effect in suppressing lead sulfate accumulation.

[0016] Also, Sc<500m 2 / g, even if Cc ≥ 0.5 mass%, the effect of suppressing the accumulation of lead sulfate cannot be obtained. Valve-regulated lead-acid batteries have less electrolyte around the lead than liquid-type batteries. On the other hand, the charge / discharge reaction is greatly affected by the ionic conductivity around the lead. When the BET specific surface area Sc is 500 m 2 By using a carbonaceous material with a content Cc of 0.5 mass % or more, a large amount of electrolyte can be retained around the lead, which increases the ionic conductivity around the lead, allowing the charge / discharge reaction to proceed more smoothly and suppressing the accumulation of lead sulfate.

[0017] However, the carbonaceous material contained in the negative electrode material can act as a starting point for accelerating the gas generation reaction during charging of a lead-acid battery. Moreover, the gas generation reaction tends to be accelerated at higher temperatures. Therefore, it is desirable for lead-acid batteries to achieve as long a life as possible even when used in high-temperature environments (e.g., the summer months in Southeast Asian countries).

[0018] Valve-regulated lead-acid batteries (VRLA), which have multiple cells and multiple cell chambers that each house the multiple cells, are available in two types: individual cell exhaust types and collective exhaust types, which have different types of control valves. The individual cell exhaust type is a type in which each of the multiple cell chambers has an independent exhaust valve. On the other hand, the collective exhaust type is a type in which one or more exhaust valves (but fewer than the number of cell chambers) that communicate with the multiple cell chambers are provided, and gases generated in the multiple cell chambers are exhausted collectively.

[0019] Fig. 1 is a cross-sectional view showing a typical structure of an individual cell exhaust type lead-acid battery, and Fig. 2 is a cross-sectional view showing a typical structure of a collective exhaust type lead-acid battery.

[0020] 1, each evacuated-cell lead-acid battery 1A includes a battery case 10 that contains a plate pack 11 and an electrolyte (not shown). The top opening of the battery case 10 is sealed with a lid 12A. The plate packs 11 are each formed by stacking a plurality of negative plate sheets 2 and positive plate sheets 3 with separators 4 interposed therebetween.

[0021] An upwardly protruding current collecting lug (not shown) is provided on the top of each of the multiple negative electrode plates 2. An upwardly protruding current collecting lug (not shown) is also provided on the top of each of the multiple positive electrode plates 3. The lugs of the negative electrode plates 2 are connected and integrated by a negative electrode strap (not shown). Similarly, the lugs of the positive electrode plates 3 are connected and integrated by a positive electrode strap (not shown). The negative electrode strap is connected to a negative electrode pole (not shown) that serves as an external terminal, and the positive electrode strap is connected to a positive electrode pole (not shown) that serves as an external terminal.

[0022] The battery case 10 is divided into multiple (three in the illustrated example) mutually independent cell chambers 10R, and each cell chamber 10R houses one electrode plate group 11. The lid 12A is equipped with an independent exhaust valve 13 for each cell chamber 10R. When the internal pressure of the cell chamber 10R exceeds a predetermined upper limit, the exhaust valve 13 opens, releasing gas directly from the cell chamber 10R to the outside. When the internal pressure of the cell chamber 10R is below the upper limit, oxygen generated in the positive electrode plate 3 is reduced by the negative electrode plate 2 in the same cell chamber 10R to produce water.

[0023] In the collective exhaust type lead-acid battery 1B shown in FIG. 2, the battery case 10 is also divided into multiple (three in the illustrated example) mutually independent cell chambers 10r, and each cell chamber 10r houses one electrode plate group 11. However, the lid 12B has a collective exhaust chamber 14r that communicates with each cell chamber via an exhaust hole 15, and each collective exhaust chamber 14r has a smaller number of exhaust valves 13 than the number of cell chambers (one in the illustrated example). When the internal pressure of the collective exhaust chamber 14r exceeds a predetermined upper limit, the exhaust valve 13 opens, releasing gas from the collective exhaust chamber 14r to the outside. When the internal pressure of the collective exhaust chamber 14r is below the upper limit, oxygen generated in the positive electrode plate 3 is reduced by the negative electrode plate 2 of any of the cell chambers 10r to produce water.

[0024] It was discovered that bulk exhaust type valve-regulated lead-acid batteries that meet conditions (A) and (B) may experience a drop in output, unstable voltage transitions, and not reach their expected lifespan under certain charge / discharge cycle conditions, including high-temperature ranges. This phenomenon is unique to bulk exhaust type batteries. When the cause was investigated, an increase in internal resistance in some cells was confirmed, and the following degradation mechanism was found.

[0025] Because the environments of the multiple cell chambers are different, the amount of electrolyte loss varies, resulting in variations in the amount of electrolyte retained. In the case of a collective exhaust type, gas can move between the cell chambers through a passage (common exhaust chamber 14r) that connects the multiple cell chambers to the exhaust valve. As a result, oxygen gas generated in cells with a large electrolyte retention volume tends to flow into cells with a relatively small electrolyte retention volume, and cells with a small electrolyte retention volume absorb more oxygen gas. Oxygen absorbed by the negative electrode plate generates PbO and is then converted to PbSO4. In other words, differences in the amount of oxygen absorbed between cells result in differences in the amount of lead sulfate produced. Such variations in the degree of sulfation increase variations in charging efficiency and electrolyte loss, accelerating the deterioration of some cells.

[0026] Therefore, a valve-regulated lead-acid battery according to one embodiment of the present invention (hereinafter also referred to as lead-acid battery A) comprises a plurality of cells and a plurality of cell chambers each accommodating the plurality of cells, each of the plurality of cells comprising a positive electrode plate, a negative electrode plate, and an electrolyte, the plurality of cell chambers each comprising an independent exhaust valve, the positive electrode plate comprising a positive electrode material, the negative electrode plate comprising a negative electrode material, the negative electrode material comprising a carbonaceous material, and satisfies condition (A) (the specific surface area Sc of the carbonaceous material measured by the BET method is 500 m or more). 2 / g) and condition (B) (the content of the carbonaceous material in the negative electrode material, Cc≧0.5 mass %) are satisfied.

[0027] In the case of individual cell exhaust types, each has an independent exhaust valve, and each exhaust valve communicates only with its corresponding cell chamber. Therefore, gas does not move between cell chambers, and oxygen gas generated in cells with a relatively low electrolyte volume does not flow into and be absorbed by cells with a relatively low electrolyte volume. This reduces the degree of sulfation variation between cells, and prevents the accelerated deterioration of some cells due to variations in charging efficiency and electrolyte loss, as occurs with bulk exhaust types. As a result, the effect of satisfying conditions (A) and (B), i.e., the significant development of conductive paths through carbonaceous material in the negative electrode material, becomes apparent, enhancing the effectiveness of suppressing sulfation in the negative plate. In individual cell exhaust types, there is a significant difference in the lifespan of valve-regulated lead-acid batteries between cases where conditions (A) and (B) are met and cases where they are not. This difference is not observed in bulk exhaust types and is a phenomenon unique to each cell exhaust type.

[0028] It is preferable that the lead-acid battery A further satisfies the following condition (C). Condition(C):650m 2 / g≦Sc≦1000m 2 / g

[0029] When condition (C) is satisfied, the effect of increasing the ionic conductivity around the lead is fully exerted, and the effects of an excessively high specific surface area are suppressed, which is thought to suppress the adsorption reaction of active ingredients in the battery (e.g., organic shrinkage inhibitors such as lignin).

[0030] Lead-acid battery A can be used for a variety of purposes, including automotive applications (four-wheeled automobiles, small mobility vehicles, etc.), industrial applications, and more. Because small mobility vehicles (e.g., motorcycles) have a higher risk of tipping over compared to four-wheeled automobiles, the use of flooded (valve-type) lead-acid batteries is restricted, and valve-regulated lead-acid batteries tend to be more widely adopted. Therefore, lead-acid battery A is particularly suitable for use in small mobility vehicles.

[0031] Lead-acid battery A satisfies conditions (A) and (B), making sulfation less likely to progress, and therefore suitable for use in PSOC conditions. Examples of applications in PSOC conditions include power sources for vehicles with idle stop (IS) control (hereinafter referred to as ISS vehicles), micro hybrid vehicles, and mild hybrid vehicles. In recent years, progress has been made in the development of small mobility vehicles equipped with idle stop (IS) control functions.

[0032] Four-wheeled vehicles with IS control functions are usually equipped with a Battery Management System (BMS) for advanced charge / discharge control of lead-acid batteries. The BMS has a built-in state-of-charge controller that controls the state of charge (SOC) of the lead-acid battery. During IS control of the four-wheeled vehicle, the state-of-charge controller controls the SOC of the lead-acid battery to, for example, between 70% and 90%. This allows regenerative energy to be charged to the lead-acid battery with as little waste as possible when the vehicle decelerates.

[0033] SOC refers to the ratio of the amount of electricity charged to the amount of electricity (100%) when the lead-acid battery is fully charged. In this specification, the 100% fully charged state of a valve-regulated lead-acid battery refers to the state when charging is completed in accordance with the full charge conditions specified in JIS D5302:2004, 8.2.2 (revised March 20, 2004).

[0034] On the other hand, small mobility vehicles such as motorcycles usually do not have charging control for regenerative energy. Therefore, lead-acid batteries for small mobility vehicles are controlled by a state-of-charge control unit to maintain a sufficiently high SOC (for example, 90% or higher) even during IS control. The more repeatedly charged and discharged at a high SOC, the more gas generation tends to increase. Therefore, lead-acid batteries for small mobility vehicles with collective exhaust are more likely to have a shorter lifespan. In contrast, lead-acid battery A with individual cell exhaust is charged and discharged at a high SOC, and can have an improved lifespan even when installed in a small mobility vehicle where gas generation is likely to increase.

[0035] Here, lead-acid batteries for small mobility vehicles refer to lead-acid batteries that fall within the scope of application of IEC 60095-7:2019 and JIS D 5302:2004. Furthermore, small mobility vehicles refer to motorcycles and power sports vehicles. Motorcycles include, for example, two-wheeled motor vehicles and three-wheeled motor vehicles, while power sports vehicles include, for example, buggies (including both three-wheeled and four-wheeled vehicles), water skis, snowmobiles, and all-terrain vehicles. Note that small mobility vehicles are equipped with a lead-acid battery A for small mobility vehicles along with an engine.

[0036] When the SOC is high, the negative electrode material contains a large amount of highly conductive lead. When the conductivity of the negative electrode material is high, the charge / discharge reaction is thought to be greatly affected by the ionic conductivity of the electrolyte around the lead. In valve-regulated lead-acid batteries, there is less electrolyte around the lead compared to liquid-type batteries. When the BET specific surface area Sc is 500 m 2 By using a carbonaceous material with a Cc content of 0.5 mass % or more, a large amount of electrolyte can be retained around the lead. This increases the ionic conductivity around the lead, allowing the charge / discharge reaction to proceed more smoothly. In other words, the use of such a carbonaceous material promotes the reaction at the interface between the lead and the electrolyte. As a result, it is believed that the accumulation of lead sulfate on the negative electrode plate is suppressed.

[0037] The vehicle of the power storage system may be a vehicle that is subjected to idling stop control when the SOC of the lead-acid battery A is equal to or greater than a threshold of 90%, and is not subjected to idling stop control when the SOC of the lead-acid battery A is less than the threshold. In a vehicle that is subjected to idling stop control when the SOC of the lead-acid battery A is equal to or greater than a threshold of 90%, and is not subjected to idling stop control when the SOC of the lead-acid battery A is less than the threshold, the state-of-charge control unit charges the lead-acid battery A at a constant voltage until it reaches a predetermined SOC when the SOC of the lead-acid battery A is less than the threshold.

[0038] Here, the "threshold" refers to a predetermined reference SOC, and "reaching the threshold" refers to the SOC becoming equal to or close to the threshold. Furthermore, an SOC close to the threshold refers to a predetermined SOC that is equal to or less than the threshold and a predetermined SOC that is higher than the threshold. Therefore, the state-of-charge control unit may start charging the lead-acid battery A when the SOC becomes equal to or less than the threshold, or may start charging the lead-acid battery A when the SOC becomes equal to or more than the threshold. Such a power storage system including a vehicle and a lead-acid battery A also corresponds to one embodiment of the present invention.

[0039] Lead-acid battery A is charged at a constant voltage while the engine is running. At this time, the alternator operates to generate electricity, and lead-acid battery A is charged at a constant voltage. During constant-voltage charging, a charging voltage is set to prevent lead-acid battery A from being overcharged. For example, if the SOC of lead-acid battery A reaches the threshold value from a value higher than the threshold value, the vehicle engine does not stop and constant-voltage charging from the alternator continues. Therefore, the SOC of lead-acid battery A is controlled to maintain above the threshold value.

[0040] Here, when charging the lead-acid battery A until the SOC reaches a threshold value or higher (for example, an SOC of 95% or higher or 99% or higher), the state-of-charge control unit preferably charges the lead-acid battery A at a constant voltage of 2.39 V / cell or higher and 2.45 V / cell or lower. For example, in the case of a lead-acid battery A consisting of six cells connected in series, it is preferable to charge the battery at a constant voltage of 14.34 V or higher and 14.7 V or lower. Charging at a voltage exceeding 14.0 V in this way more effectively suppresses the progression of stratification and sulfation in the lead-acid battery.

[0041] FIG. 3 is a block diagram schematically illustrating a power storage system having the above configuration. The power storage system 20 includes a lead-acid battery A, a vehicle 30 that receives power from the lead-acid battery A, and a state-of-charge control unit 40 that controls the SOC of the lead-acid battery A. The state-of-charge control unit 40 includes a charge control unit 41 that controls charging of the lead-acid battery A. The vehicle 30 is an idle reduction vehicle (IS vehicle) equipped with an idle reduction system (IDS) controlled by an IS control unit 50. An IDS system is sometimes referred to as an ISS. An ISS is a system that controls an engine 60 to stop when the vehicle is parked or stopped. In an ISS, the current required for the vehicle while the engine is stopped is supplied by a battery installed in the vehicle. In an ISS, the engine is restarted when the battery's SOC reaches a predetermined threshold while the engine is stopped. The period from when the engine is stopped due to parking or stopping the vehicle to when it is restarted is referred to as the idle reduction period (IS period). Idling stop control (IS control) refers to a control in which, when the SOC of lead-acid battery A is controlled to maintain a threshold of 90% or more, the charge state control unit 40 charges lead-acid battery A at a constant voltage of 2.39 V / cell or more and 2.45 V / cell or less when the SOC of lead-acid battery A reaches the threshold during the IS period.

[0042] The negative electrode material may further contain an organic shrinkage preventer. This can improve low-temperature high-rate (HR) discharge performance. However, if the organic shrinkage preventer is adsorbed onto the carbonaceous material, the shrinkage-preventing effect of the organic shrinkage preventer is less likely to be exhibited. When a carbonaceous material with a large specific surface area Sc is used, the effect of adsorption of the organic shrinkage preventer by the carbonaceous material is more likely to be apparent. From the perspective of ensuring higher low-temperature HR discharge performance, it is preferable that the content of the organic shrinkage preventer in the negative electrode material, Ce (mass%), satisfies Ce > 0.368 Cc + 0.054. Note that the organic shrinkage preventer increases the hydrogen generating overvoltage by coating the lead surface, and is therefore thought to also have the effect of suppressing the loss of electrolyte.

[0043] It is more preferable that the content of the organic shrinkage inhibitor, Ce, satisfies the relationship 0.372Cc + 0.092≦Ce≦0.373Cc + 0.249. By satisfying 0.372Cc + 0.092≦Ce, low-temperature HR discharge performance and the effect of suppressing electrolyte loss can be further improved. Furthermore, by satisfying Ce≦0.373Cc + 0.249, excessive coating of the carbonaceous material and lead by the organic shrinkage inhibitor can be suppressed. By maintaining the high conductivity of the negative electrode material, a decrease in charge acceptance can be suppressed.

[0044] Lead-acid battery A is required to have an excellent balance of lead sulfate accumulation suppression, low-temperature HR discharge performance, charge acceptance, and electrolyte loss suppression effect over a wide temperature range. 2 By using a carbonaceous material satisfying the condition of / g≦Sc and adjusting the content Ce of the organic shrinkage preventer according to the content Cc of the carbonaceous material using the above formula, the balance of the above characteristics can be adjusted with high precision. Therefore, even when the lead-acid battery A is used in various regions around the world, it can exhibit excellent performance and achieve stable quality.

[0045] (Positive electrode material) In a positive electrode plate, the positive electrode material is usually held by a positive current collector. The positive electrode material is the positive electrode plate excluding the positive current collector. A member such as a mat or pasting paper may be attached to the positive electrode plate. Such a member (also called an attachment member) is used integrally with the positive electrode plate and is therefore included in the positive electrode plate. When the positive electrode plate includes an attachment member, the positive electrode material is the positive electrode material excluding the positive electrode collector and the attachment member.

[0046] The lead-acid battery A according to the embodiment of the present invention will be described in more detail below, although the present invention is not limited to the following embodiment.

[0047] (negative plate) (Negative electrode material) A negative electrode plate typically includes a negative current collector and a negative electrode material, and the negative electrode material is held by the negative current collector. The negative electrode material is the negative electrode plate excluding the negative current collector. A member such as a mat or pasting paper may be attached to the negative electrode plate. Such a member (also referred to as an attachment member) is used integrally with the negative electrode plate and is therefore included in the negative electrode plate. When the negative electrode plate includes an attachment member, the negative electrode material is the negative electrode material excluding the negative electrode collector and the attachment member.

[0048] The negative electrode material contains, as an essential component, a negative electrode active material (lead or lead sulfate) that develops capacity through an oxidation-reduction reaction. The negative electrode active material in a charged state is sponge lead, but unformed negative electrodes are usually made using lead powder. The negative electrode material also contains a carbonaceous material as an additive. The negative electrode material may also contain additives other than the carbonaceous material (such as an organic shrinkage inhibitor or barium sulfate).

[0049] (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. A lattice-shaped current collector is preferably used as the negative electrode current collector because it is easy to support the negative electrode material.

[0050] The lead alloy used for the negative electrode current collector may be either a Pb-Ca alloy or a Pb-Ca-Sn 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, etc. 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 on a part of the negative electrode current collector. The surface layer may be formed on the lug portion of the negative electrode current collector. The surface layer of the lug portion may contain Sn or an Sn alloy.

[0051] (carbonaceous material) Examples of carbonaceous materials contained in the negative electrode material include carbon black, graphite, hard carbon, and soft carbon. Examples of carbon black include acetylene black, furnace black, and lamp black. Furnace black also includes Ketjen Black (trade name). The graphite may be any carbonaceous material containing a graphite-type crystalline structure, and may be either artificial graphite or natural graphite. One type of carbonaceous material may be used alone, or two or more types may be used in combination.

[0052] Among carbonaceous materials, the 1300 cm -1 More than 1350cm -1 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. Graphite may be either artificial graphite or natural graphite.

[0053] The specific surface area (BET specific surface area) of carbonaceous materials measured by the BET (Brunauer-Emmett-Teller) method is 500m 2 / g or more. BET specific surface area Sc is 500m 2When the BET specific surface area Sc is less than 650 m / g, it is difficult to sufficiently suppress the accumulation of lead sulfate on the negative electrode plate even if the content of the carbonaceous material is 0.5 mass % or more. 2 / g or more is preferable, and 750m 2 / g or more is more preferable, and 800m 2 / g or more. From the viewpoint of ensuring a higher suppression of lead sulfate accumulation, the BET specific surface area Sc may be 1000 m 2 The BET specific surface area is a specific surface area determined by the BET equation in a gas adsorption method using nitrogen gas as the adsorption gas.

[0054] From the viewpoint of easily controlling the BET specific surface area Sc of the carbonaceous material within the above range, the carbonaceous material preferably contains at least furnace black (particularly, Ketjen black). The carbonaceous material may contain furnace black (particularly, Ketjen black) and other carbonaceous materials. When two or more types of carbonaceous materials are combined, the types of carbonaceous materials to be combined may be selected or their ratios may be adjusted so that the BET specific surface area Sc of the entire carbonaceous material falls within the above range.

[0055] The carbonaceous material content Cc in the negative electrode material is 0.5% by mass or more. When the carbonaceous material content Cc is less than 0.5% by mass, the effect of suppressing lead sulfate accumulation in the negative electrode plate does not depend on the BET specific surface area Sc of the carbonaceous material. From the viewpoint of ensuring a higher effect of suppressing lead sulfate accumulation, the carbonaceous material content Cc may be 0.75% by mass or more. The carbonaceous material content Cc may be, for example, 2% by mass or less, or 1.75% by mass or less.

[0056] The carbonaceous material content Cc may be 0.5 mass % or more and 2 mass % or less (or 1.75 mass % or less), or 0.75 mass % or more and 2 mass % or less (or 1.75 mass % or less).

[0057] (organic shrinkage preventer) The organic shrinkage preventer is an organic compound that has the function of suppressing the shrinkage of lead, which is the negative electrode active material, when a lead-acid battery is repeatedly charged and discharged. As the organic shrinkage preventer, for example, at least one selected from the group consisting of lignin compounds and synthetic organic shrinkage preventers may be used.

[0058] Examples of lignin compounds include lignin and lignin derivatives, etc. Examples of lignin derivatives include lignin sulfonic acid or salts thereof (such as alkali metal salts (such as sodium salts)).

[0059] The synthetic organic expander used in lead-acid batteries is usually an organic condensation product (hereinafter simply referred to as a condensation product). A condensation product is a synthetic product that can be obtained by utilizing a condensation reaction. The condensation product may contain an aromatic compound unit (hereinafter also referred to as an aromatic compound unit). The aromatic compound unit refers to a unit derived from an aromatic compound incorporated into the condensation product. In other words, the aromatic compound unit is a residue of an aromatic compound. The condensation product may contain one type of aromatic compound unit, or two or more types.

[0060] Examples of condensates include condensates of aromatic compounds with aldehyde compounds. Such condensates may be synthesized by reacting an aromatic compound with an aldehyde compound. Condensates containing sulfur can be obtained by reacting an aromatic compound with an aldehyde compound in the presence of a sulfite or by using an aromatic compound containing sulfur (e.g., bisphenol S) as the aromatic compound. For example, the sulfur content in the condensate can be adjusted by adjusting at least one of the amount of sulfite and the amount of the aromatic compound containing sulfur. This method can also be used when using other raw materials. One or more aromatic compounds may be condensed to obtain a condensate. The aldehyde compound may be an aldehyde (e.g., formaldehyde) or a condensate (or polymer) of an aldehyde. Examples of aldehyde condensates (or polymers) include paraformaldehyde, trioxane, and tetraoxymethylene. The aldehyde compounds may be used alone or in combination. Formaldehyde is preferred from the viewpoint of high reactivity with aromatic compounds.

[0061] The aromatic compound may have a sulfur-containing group. That is, the condensate may be an organic polymer containing multiple aromatic rings in the molecule and containing elemental sulfur as a sulfur-containing group. The sulfur-containing group may be directly bonded to the aromatic ring of the aromatic compound, or may be bonded to the aromatic ring as an alkyl chain having a sulfur-containing group, for example. Among the sulfur-containing groups, a sulfonic acid group or a sulfonyl group, which are stable, is preferred. The sulfonic acid group may exist in an acid form or in a salt form such as a sodium salt.

[0062] Examples of aromatic rings that aromatic compounds have include benzene rings and naphthalene rings. When an aromatic compound has multiple aromatic rings, the multiple aromatic rings may be linked by a direct bond or a linking group (e.g., an alkylene group (including an alkylidene group), a sulfone group), etc. Examples of such structures include bisarene structures (biphenyl, bisphenylalkane, bisphenylsulfone, etc.).

[0063] Examples of aromatic compounds include compounds having the above-mentioned aromatic ring and a functional group (such as a hydroxy group or an amino group). The functional group may be directly bonded to the aromatic ring, or may be bonded as an alkyl chain having the functional group. The hydroxy group also includes a salt of the hydroxy group (-OMe). The amino group also includes a salt of the amino group (a salt with an anion). Examples of Me include alkali metals (such as Li, K, and Na) and metals of Group 2 of the periodic table (such as Ca and Mg). The aromatic compound may have a sulfur-containing group and a substituent other than the above-mentioned functional group (such as an alkyl group or an alkoxy group) on the aromatic ring.

[0064] The aromatic compound that is the source of the aromatic compound unit may be at least one selected from the group consisting of bisarene compounds and monocyclic aromatic compounds.

[0065] Examples of bisarene compounds include bisphenol compounds, hydroxybiphenyl compounds, and bisarene compounds having an amino group (such as bisarylalkane compounds having an amino group, bisarylsulfone compounds having an amino group, and biphenyl compounds having an amino group). Among these, bisphenol compounds are preferred.

[0066] The bisphenol compound is preferably bisphenol A, bisphenol S, bisphenol F, or the like. For example, the bisphenol compound may include at least one selected from the group consisting of bisphenol A and bisphenol S. By using bisphenol A or bisphenol S, an excellent shrinkage prevention effect can be obtained for the negative electrode material.

[0067] The bisphenol compound may have a bisphenol skeleton, and the bisphenol skeleton may have a substituent. That is, bisphenol A may have a bisphenol A skeleton, and the skeleton may have a substituent. Bisphenol S may have a bisphenol S skeleton, and the skeleton may have a substituent.

[0068] Preferred monocyclic aromatic compounds include hydroxymonoarene compounds and aminomonoarene compounds, with hydroxymonoarene compounds being particularly preferred.

[0069] Examples of the hydroxymonoarene compound include a hydroxynaphthalene compound and a phenol compound. For example, it is preferable to use a phenolic compound, such as a phenolsulfonic acid compound (phenolsulfonic acid or its substituted derivatives). As mentioned above, the phenolic hydroxy group also includes a salt of the phenolic hydroxy group (-OMe).

[0070] Examples of the aminomonoarene compound include aminonaphthalene compounds and aniline compounds (aminobenzenesulfonic acid, alkylaminobenzenesulfonic acid, etc.).

[0071] As described above, the negative electrode material contains a carbonaceous material with a relatively large BET specific surface area Sc. When such a carbonaceous material is used, the organic shrinkage preventer may be adsorbed onto the carbonaceous material, making it difficult to effectively utilize the effects of the organic shrinkage preventer. To more effectively utilize the effects of using the organic shrinkage preventer, the content Ce of the organic shrinkage preventer contained in the negative electrode material is preferably determined according to the BET specific surface area Sc of the carbonaceous material. To ensure higher constant-temperature HR discharge performance, the content Ce of the organic shrinkage preventer in the negative electrode material preferably satisfies Ce > 0.368 Cc + 0.054 (1). To further enhance low-temperature HR discharge performance and the effect of suppressing electrolyte loss, the content Ce of the organic shrinkage preventer is preferably 0.372 Cc + 0.092 ≦ Ce (2). Furthermore, to enhance the effect of suppressing a decrease in charge acceptance, the content Ce of the organic shrinkage preventer is preferably Ce ≦ 0.373 Cc + 0.249 (3). These relationships are based on the BET specific surface area Sc of the carbonaceous material being 500m 2 / g or more (or 650m 2 / g or more, 750m 2 / g or more or 800m 2 / g or more), 1000m 2This holds true in the range of / g or less.

[0072] The relationships (1) to (3) above were obtained from the results of evaluating the low-temperature HR discharge performance, charge acceptance, and electrolyte reduction by using multiple carbonaceous materials with different BET specific surface areas Sc and varying the carbonaceous material content Cc and the organic shrinkage inhibitor content Ce.

[0073] (barium sulfate) The negative electrode material may contain barium sulfate. The content of barium sulfate in the negative electrode material is, for example, 0.05% by mass or more, or may be 0.10% by mass or more. The content of barium sulfate in the negative electrode material is, for example, 3% by mass or less, or may be 2% by mass or less.

[0074] The content of barium sulfate in the negative electrode material may be 0.05% by mass to 3% by mass, 0.05% by mass to 2% by mass, 0.10% by mass to 3% by mass, or 0.10% by mass to 2% by mass.

[0075] (Analysis of the components of negative electrode materials) The following describes the method for analyzing negative electrode materials or their constituents. Prior to analysis, a fully charged lead-acid battery is disassembled to obtain the 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 should be within two hours. The washed negative electrode plate is dried under reduced pressure at 60±5°C for approximately six hours. After drying, if the negative electrode plate contains an adhesive material, the adhesive material is removed from the negative electrode plate by peeling. Next, the negative electrode material is separated from the negative electrode plate to obtain a sample (hereinafter referred to as sample A), and the mass (MO) of sample A is measured. Sample A is crushed as necessary and subjected to analysis.

[0076] A fully charged lead-acid battery refers to a fully charged lead-acid battery that has already been formed. A lead-acid battery can be fully charged immediately after formation, or after some time has passed since formation (for example, a lead-acid battery that has been in use (preferably in the early stages of use) after 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 at all.

[0077] (1) Analysis of organic shrinkage inhibitors (1-1) Qualitative analysis of organic shrinkage inhibitors in negative electrode materials The crushed sample A is immersed in a 1 mol / L aqueous solution of sodium hydroxide (NaOH) to extract the organic shrink-regulating agent. If the extract contains multiple organic shrink-regulating agents, each organic shrink-regulating agent is then separated from the extract. For each of the isolated organic shrink-regulating agents, insoluble components are removed by filtration, and the resulting solution is desalted, concentrated, and dried. Desalting is performed using a desalting column, by passing the solution through an ion exchange membrane, or by placing the solution in a dialysis tube and immersing it in distilled water. Drying this yields a powder sample of the organic shrink-regulating agent (hereinafter referred to as sample B).

[0078] The type of organic shrink-preventing agent is identified by combining information obtained from the infrared spectrum measured using sample B of the organic shrink-preventing agent obtained in this manner, the ultraviolet-visible absorption spectrum measured using an ultraviolet-visible spectrophotometer after diluting sample B with distilled water or the like, or the NMR spectrum of a solution obtained by dissolving sample B in a specified solvent such as heavy water.

[0079] (1-2) Quantitative determination of the content of organic shrinkage inhibitor in negative electrode material As in (1-1) above, for each of the separated products containing the organic shrinkage inhibitor, insoluble components are removed by filtration to obtain a solution. The ultraviolet-visible absorption spectrum of each of the obtained solutions is measured. The content of each organic shrinkage inhibitor in the negative electrode material is determined using the intensity of the peak characteristic of each organic shrinkage inhibitor and a previously prepared calibration curve.

[0080] When obtaining a lead-acid battery with an unknown content of organic shrinkage preventer and measuring the content of the organic shrinkage preventer, it may be impossible to precisely identify the structural formula of the organic shrinkage preventer, and therefore the same organic shrinkage preventer cannot be used for the calibration curve. In this case, a calibration curve is created using a separately available organic polymer that shows similar shapes in the ultraviolet-visible absorption spectrum, infrared spectroscopy spectrum, NMR spectrum, etc. to the organic shrinkage preventer extracted from the negative electrode of the battery, and the content of the organic shrinkage preventer is measured using the ultraviolet-visible absorption spectrum.

[0081] (2) Determination of carbonaceous materials and barium sulfate 50 ml of 20% nitric acid by mass was added to 10 g of crushed sample A, and the mixture was heated for approximately 20 minutes to dissolve the lead component as lead nitrate. The solution containing lead nitrate was then filtered to separate out the carbonaceous material, barium sulfate, and other solid components.

[0082] 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 obtained sample is a mixed sample of the carbonaceous material and barium sulfate (hereinafter referred to as Sample C). The mass of the membrane filter is subtracted from the total mass of Sample C and the membrane filter after drying to determine the mass of Sample C (M m ) is measured. After that, the dried sample C is placed in a crucible together with the membrane filter and burnt at 700°C or higher to be incinerated. 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 ) to find the mass M m to mass M B The mass of the carbonaceous material is calculated by subtracting the mass of the lead sulfate from the mass of the carbonaceous material. The ratio (mass %) of each mass to the mass of sample A is calculated and this is taken as the carbonaceous material content Cc and the lead sulfate content in the negative electrode material.

[0083] (3) BET specific surface area Sc of carbonaceous material (3-1) Separation of carbonaceous materials A predetermined amount of crushed sample A is collected and its mass is measured. 30 mL of 60% by mass nitric acid aqueous solution is added to this sample A per 5 g of sample A and heated at 70°C ± 5°C. 10 g of disodium ethylenediaminetetraacetate, 30 mL of 28% by mass ammonia water, and 100 mL of water are added to the resulting mixture per 5 g of sample A, and heating is continued to dissolve the soluble components. In this way, sample A is pretreated. The dispersion obtained by pretreatment is filtered using a membrane filter (0.1 μm mesh size) to recover the solids. The recovered sample is sieved through a 500 μm mesh size sieve to remove large components (such as reinforcing materials), and the components that pass through the sieve are recovered as carbonaceous material.

[0084] (3-2) Measurement of BET specific surface area Sc The BET specific surface area Sc of the carbonaceous material recovered in (3-1) above is determined by gas adsorption using the BET equation. More specifically, the carbonaceous material is pretreated by heating it in a nitrogen flow at a temperature of 150°C ± 5°C for 1 hour. The BET specific surface area of ​​the pretreated carbonaceous material is determined using the following apparatus under the following conditions, and this is taken as the BET specific surface area Sc of the carbonaceous material. Measurement equipment: Micromeritics TriStar 3000 Adsorption gas: Nitrogen gas with a purity of 99.99% or higher Adsorption temperature: boiling point of liquid nitrogen (77K) BET specific surface area calculation method: Complies with JIS Z 8830:2013 7.2

[0085] (others) The negative electrode plate can be formed by applying or filling a negative electrode paste to a negative electrode current collector, aging and drying the paste to produce an unformed negative electrode plate, and then chemically forming the unformed negative electrode plate. The negative electrode paste is produced by adding water and sulfuric acid to lead powder, an organic shrinkage inhibitor, and various additives as needed, and kneading the mixture. During aging, the unformed negative electrode plate is preferably aged at a temperature higher than room temperature and at a high humidity.

[0086] The formation can be carried out by immersing an electrode plate assembly including unformed negative plates in an electrolyte containing sulfuric acid in a battery jar of a lead-acid battery and then charging the electrode plate assembly. However, the formation can also be carried out before assembling the lead-acid battery or the electrode plate assembly. The formation produces spongy lead.

[0087] (positive electrode plate) A positive electrode plate typically includes a positive electrode current collector and a positive electrode material. The positive electrode material is held by the positive electrode current collector. Positive electrode plates for lead-acid batteries can be classified into paste type, clad type, etc. Paste type positive electrode plates are preferably used.

[0088] 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.

[0089] As the lead alloy used for the positive electrode current collector, a Pb-Ca alloy or a Pb-Ca-Sn 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 on 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.

[0090] In a paste-type positive electrode plate, the positive electrode material is the positive electrode plate excluding the positive electrode current collector. A mat, pasting paper, or other member may be attached to the positive electrode plate. Such members (attaching members) are used integrally with the positive electrode plate and are therefore considered to be included in the positive electrode plate. Furthermore, when the positive electrode plate includes an attaching member (such as a mat or pasting paper), the positive electrode material in a paste-type positive electrode plate is the positive electrode plate excluding the positive electrode current collector and the attaching member.

[0091] The positive electrode material contained in the positive electrode plate includes a positive electrode active material (lead dioxide or lead sulfate) that generates capacity through an oxidation-reduction reaction. The positive electrode material may also contain other additives as needed.

[0092] An unformed paste-type positive electrode plate is 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.

[0093] A positive electrode plate can be obtained by chemically forming an unformed positive electrode plate. Chemical formation can be performed by immersing an electrode plate assembly including the unformed positive electrode plate in an electrolyte containing sulfuric acid in a battery container of a lead-acid battery and then charging the electrode plate assembly. However, chemical formation may also be performed before assembling the lead-acid battery or the electrode plate assembly.

[0094] (separator) A lead-acid battery A typically includes a separator interposed between the positive and negative electrode plates. The separator is made of nonwoven fabric. The nonwoven fabric is a mat of intertwined glass fibers. The thickness of the separator interposed between the negative and positive electrode plates can be selected according to the distance between the electrodes. The number of separators can be selected according to the number of gaps between the electrodes.

[0095] Nonwoven fabrics are primarily composed of fibers. Examples of fibers that can be used include glass fibers, polymer fibers (such as polyolefin fibers, acrylic fibers, and polyester fibers (such as polyethylene terephthalate fibers)), and pulp fibers. Among these, glass fibers are preferred. Nonwoven fabrics may also contain components other than fibers, such as acid-resistant inorganic powders and polymers as binders.

[0096] The average fiber diameter of the glass fibers is preferably, for example, 0.1 μm or more and 25 μm or less. The average fiber diameter can be determined by arbitrarily selecting 10 or more fibers and taking an enlarged photograph of the selected fibers. Note that the glass fibers may not only be of a single fiber diameter, but may also be a mixture of multiple fiber diameters (for example, 1 μm glass fibers and 10 μm glass fibers).

[0097] The nonwoven fabric may contain, in addition to glass fibers, a fibrous material insoluble in the electrolyte solution. Examples of fibrous materials other than glass fibers include polymer fibers (polyolefin fibers, acrylic fibers, polyester fibers such as polyethylene terephthalate fibers, etc.), pulp fibers, etc. The nonwoven fabric is preferably formed, for example, of 60% by mass or more of fibrous materials. The proportion of glass fibers in the fibrous materials constituting the nonwoven fabric is preferably 60% by mass or more. The nonwoven fabric may also contain inorganic powders (for example, silica powder, glass powder, diatomaceous earth), etc.

[0098] The separator may be composed of only a nonwoven fabric. If necessary, the separator may be a laminate of a nonwoven fabric and a microporous membrane, a laminate of a nonwoven fabric and the same or a different material, or a laminate of a nonwoven fabric and the same or a different material with interlocking recesses and projections.

[0099] A microporous membrane is a porous sheet mainly composed of components other than fiber components. A microporous membrane can be obtained, for example, by extruding a composition containing a pore-forming agent (such as at least one of a polymer powder and an oil) into a sheet, and then removing the pore-forming agent to form pores. Microporous membranes are preferably made of acid-resistant materials. Furthermore, those mainly composed of polymer components are preferred. The polymer component is preferably polyolefin (such as polyethylene or polypropylene).

[0100] (electrolyte) The electrolyte is an aqueous solution containing sulfuric acid. The electrolyte may be gelled as needed before use in a lead-acid battery. The electrolyte may contain at least one selected from the group consisting of cations (e.g., metal cations) and anions (e.g., anions other than sulfate anions (e.g., phosphate ions)). Examples of metal cations include at least one selected from the group consisting of sodium ions, lithium ions, magnesium ions, and aluminum ions.

[0101] The specific gravity of the electrolyte in a fully charged lead-acid battery at 20°C is, for example, 1.20 or more, and may be 1.25 or more. The specific gravity of the electrolyte at 20°C is, for example, 1.35 or less, and preferably 1.32 or less.

[0102] The specific gravity of the electrolyte in a fully charged lead-acid battery at 20°C may be 1.20 or more and 1.35 or less, 1.20 or more and 1.32 or less, 1.25 or more and 1.35 or less, or 1.25 or more and 1.32 or less.

[0103] A lead-acid battery can be obtained by a manufacturing method including a step of assembling a lead-acid battery by placing a positive electrode plate, a negative electrode plate, and an electrolyte in a battery case. In the step of assembling a lead-acid battery, a separator is usually disposed between the positive electrode plate and the negative electrode plate. The step of assembling a lead-acid battery may include a step of chemically converting at least one of the positive electrode plate and the negative electrode plate, if necessary, after the step of placing the positive electrode plate, the negative electrode plate, and the electrolyte in the battery case. The positive electrode plate, the negative electrode plate, the electrolyte, and the separator are each prepared before being placed in the battery case.

[0104] A lead-acid battery may include at least one cell having the above-described negative electrode plate. From the viewpoint of ensuring an excellent effect of suppressing the accumulation of lead sulfate in the entire lead-acid battery, it is preferable that 50% or more (or 75% or more) of the cells constituting the lead-acid battery have the above-described negative electrode plate, and it is more preferable that all of the cells have the above-described negative electrode plate.

[0105] A valve-regulated lead-acid battery according to one aspect of the present invention and an electricity storage system including the same will be described below.

[0106] (1) A valve-regulated lead-acid battery, A plurality of cells and a plurality of cell chambers each containing the plurality of cells, Each of the plurality of cells includes a positive electrode plate, a negative electrode plate, and an electrolyte; The plurality of cell chambers each have an exhaust valve independent of one another, the positive electrode plate comprises a positive electrode material; the negative electrode plate comprises a negative electrode material; the negative electrode material includes a carbonaceous material, The specific surface area of ​​the carbonaceous material by the BET method: Sc is Sc≧500m 2 / g is satisfied, A valve-regulated lead-acid battery, wherein the content Cc of the carbonaceous material in the negative electrode material satisfies Cc≧0.5% by mass.

[0107] (2) The specific surface area Sc is Sc≦1000 m 2 / g.

[0108] (3) The specific surface area Sc is 650 m 2 / g≧Sc.

[0109] (4) The specific surface area Sc is 750 m 2 The valve-regulated lead-acid battery according to any one of (1) to (3) above, which satisfies / g≧Sc.

[0110] (5) The valve-regulated lead-acid battery according to any one of (1) to (4) above, wherein the content Cc satisfies Cc≦2.0 mass %.

[0111] (6) The valve-regulated lead-acid battery according to any one of (1) to (5) above, wherein the content Cc satisfies 0.75 mass %≦Cc≦1.75 mass %.

[0112] (7) a valve-regulated lead-acid battery; a vehicle that receives a supply of power from the valve-regulated lead-acid battery; a state of charge control unit that controls the SOC of the valve-regulated lead-acid battery, The valve-regulated lead-acid battery includes a plurality of cells and a plurality of cell chambers that respectively accommodate the plurality of cells, Each of the plurality of cells includes a positive electrode plate, a negative electrode plate, and an electrolyte; The plurality of cell chambers each have an exhaust valve independent of each other, the negative electrode plate comprises a negative electrode material including a carbonaceous material, The specific surface area of ​​the carbonaceous material by the BET method: Sc is Sc≧500m 2 / g is satisfied, the content Cc of the carbonaceous material in the negative electrode material satisfies Cc≧0.5% by mass, The vehicle is subjected to idling stop control when the SOC of the valve-regulated lead-acid battery is equal to or greater than a threshold of 90%, and is not subjected to idling stop control when the SOC of the valve-regulated lead-acid battery is less than the threshold.

[0113] (8) The specific surface area Sc is Sc≦1000 m 2 / g.

[0114] (9) The specific surface area Sc is 650 m 2 The electricity storage system according to (7) or (8) above, which satisfies / g≧Sc.

[0115] (10) The specific surface area Sc is 750 m 2 The electricity storage system according to any one of (7) to (9) above, which satisfies / g≧Sc.

[0116] (11) The electricity storage system according to any one of (7) to (10) above, wherein the content Cc satisfies Cc≦2.0 mass %.

[0117] (12) The electricity storage system according to any one of (7) to (11) above, wherein the content Cc satisfies 0.75 mass %≦Cc≦1.75 mass %.

[0118] (13) The power storage system according to any one of (7) to (12) above, wherein the state-of-charge control unit charges the valve-regulated lead-acid battery at a constant voltage when the SOC of the valve-regulated lead-acid battery is less than the threshold value.

[0119] (14) The power storage system according to any one of (7) to (13) above, wherein the charging at the constant voltage is performed at 2.30 V / cell or more and 2.45 V / cell or less.

[0120] (15) The power storage system according to any one of (7) to (14) above, wherein the vehicle is a small mobility vehicle.

[0121] [Example] 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.

[0122] 《Lead acid battery A》 A lead-acid battery is produced by the following procedure. (a) Preparation of the negative electrode plate The raw material lead powder, barium sulfate, carbonaceous material, organic shrinkage preventer (sodium lignosulfonate), and an appropriate amount of sulfuric acid aqueous solution are mixed to obtain a negative electrode paste. At this time, the carbonaceous material is mixed so that the content of the carbonaceous material determined by the above-mentioned procedure is 1.0 mass %. The carbonaceous material is selected from those having a BET specific surface area Sc determined by the above-mentioned procedure of 750 m 2 / g of carbon black is used. The negative electrode paste is filled into the mesh portion of a lattice-shaped negative electrode current collector, and the negative electrode is aged and dried to obtain an unformed negative electrode plate.

[0123] (b) Preparation of the positive electrode plate The raw material lead powder is mixed with an aqueous sulfuric acid solution to obtain a positive electrode paste, which is then filled into the mesh of a lattice-shaped positive electrode current collector, aged, and dried to obtain an unformed positive electrode plate.

[0124] (c) Assembly of lead-acid batteries An electrode assembly is formed by stacking four unformed negative electrodes and three unformed positive electrodes, with separators interposed between the negative and positive electrodes. A glass fiber nonwoven fabric sheet is used as the separator.

[0125] The electrode plate group is placed in a polypropylene battery case together with the electrolyte, and the case is sealed with an exhaust-type lid for each cell to assemble the lead-acid battery. The assembled battery is then chemically formed to complete the exhaust-type lead-acid battery A (VRLA for small mobility vehicles). The rated voltage of lead-acid battery A is 12V, and the rated 10-hour rate capacity is 5Ah. The specific gravity of the electrolyte after chemical formation is 1.32.

[0126] 《Lead acid battery AR》 A lead-acid battery is assembled and subjected to chemical formation in the same manner as the lead-acid battery A, except that the carbonaceous material is mixed into the negative electrode paste so that the content of the carbonaceous material obtained by the procedure described above becomes 0.3 mass %, and an evacuated-type lead-acid battery A for each cell is completed.

[0127] 《Lead acid battery B》 Except for the use of a bulk exhaust type lid, the lead acid battery is assembled in the same manner as the lead acid battery A, and chemical formation is performed to complete the bulk exhaust type lead acid battery A.

[0128] 《Lead acid battery BR》 A lead-acid battery is assembled and subjected to chemical formation in the same manner as in the lead-acid battery B, except that the carbonaceous material is mixed into the negative electrode paste so that the content of the carbonaceous material obtained by the procedure described above becomes 0.3 mass %, and a bulk exhaust-type lead-acid battery A is completed.

[0129] [Evaluation of lead-acid batteries] After fully charging, the lead-acid battery is subjected to the following charge-discharge cycles: 5,000 cycles at 25°C ± 2°C and 2,500 cycles at 40°C ± 2°C. After that, the following charge-discharge cycles are repeated at 10°C ± 2°C until the voltage at the end of discharge of the IS discharge (3) below reaches 6V.

[0130] If the voltage at the end of the discharge did not reach 6 V at the 10,000th cycle in total, the cycle was repeated for 5,000 cycles at 25°C ± 2°C, followed by 2,500 cycles at 40°C ± 2°C, and then at 10°C ± 2°C until the voltage at the end of the IS discharge (3) described below reached a predetermined value.

[0131] <Charge / discharge cycle schedule> (a) IS discharge (1): Discharge for 20 seconds at a current value (A) twice the value stated as the rated 10-hour rate capacity (Ah). (b) Discharge equivalent to restarting: Discharge for one second at a current value (A) six times the value stated as the rated 10-hour rate capacity (Ah). (c) Discharge equivalent to motor acceleration: Discharge for 0.5 seconds at a current value (A) 15 times the value listed as the rated 10-hour rate capacity (Ah). (d) Constant voltage charging (1): Charge for 50 seconds at a constant voltage of 2.42 V ± 0.03 V / cell (approximately 14.52 V / 6 cells) with the current value (A) listed as the rated 10-hour rate capacity (Ah) as the maximum current. (e) IS discharge (2): Discharge for 20 seconds at a current value (A) twice the value stated as the rated 10-hour rate capacity (Ah). (f) Discharge equivalent to restarting: Discharge for one second at a current value (A) six times the value stated as the rated 10-hour rate capacity (Ah). (g) Discharge equivalent to motor acceleration: Discharge for 0.3 seconds at a current value (A) 20 times the value listed as the rated 10-hour rate capacity (Ah). (h) IS discharge (3): Discharge for 3 seconds at a current value (A) eight times the value listed as the rated 10-hour rate capacity (Ah). (i) Constant voltage charging (2): Charge for 100 seconds at a constant voltage of 2.42 V ± 0.03 V / cell (approximately 14.52 V / 6 cells) with the current value (A) indicated as the rated 10-hour rate capacity (Ah) as the maximum current.

[0132] The results for lead-acid batteries A, AR, B, and BR are shown in Table 1. Note that lead-acid battery A reached 6 V at the end of IS discharge (3) at the 17,720th cycle in total, reaching the end of its life. The end-of-discharge voltage at 10,000 cycles was maintained at 8.6 V. The other batteries reached 6 V at 10,000 cycles or less. For batteries whose end-of-discharge voltage reached 6 V before reaching 10,000 cycles, the end-of-discharge voltage at 10,000 cycles could not be measured, so they are shown as "-" in Table 1.

[0133] [Table 1]

[0134] Next, for the lead-acid batteries A and AR with each cell exhaust, the charging voltage of the constant voltage charging (1) and (2) in the above schedule was changed from 2.42 V ± 0.03 V / cell (approximately 14.52 V / 6 cells) to 2.33 V ± 0.03 V / cell (approximately 13.98 V / 6 cells), and the same charge-discharge cycle was repeated. The results are shown in Table 2.

[0135] [Table 2]

[0136] Comparing Tables 1 and 2, it can be seen that when constant voltage charging is performed at a voltage exceeding 14.0 V, stratification and the progression of sulfation in lead-acid batteries are more effectively suppressed.

[0137] 《Lead acid battery C1~C16》 Similar to the lead-acid battery A, except that a carbonaceous material having a specific surface area of ​​the Sc value shown in Table 3 is mixed into the negative electrode paste so that the content of the carbonaceous material determined by the above-described procedure becomes the Cc value shown in Table 3, the lead-acid batteries are assembled and subjected to chemical formation, and each of the cell-evacuated lead-acid batteries C1 to C16 is completed.

[0138] The results are shown in Table 3.

[0139] [Table 3]

[0140] As shown in Table 3, when the carbonaceous material content Cc in the negative electrode material is 0.5 mass% or more, a high sustained voltage is obtained, and it can be seen that stratification and the progression of sulfation in lead-acid batteries are effectively suppressed. 2 / g or more (especially 1000m 2 / g or less), a high sustaining voltage can be obtained. 2 / g or more, stratification and sulfation of the lead-acid battery cannot be suppressed.

[0141] 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. [Industrial Applicability]

[0142] Valve-regulated lead-acid batteries (VRLA) are suitable for small mobility or IS vehicle applications, etc. However, these applications are merely examples and are not intended to be limiting. [Explanation of symbols]

[0143] 1A: Each cell is evacuated and has lead-acid storage capacity 1B: Bulk exhaust type lead acid battery 2: Negative electrode plate 3: Positive electrode plate 4: Separator 11: Plate group 10:Battery container 10R, 10r: Cell room 12A: Lid 13: Exhaust valve 14r: Integrated exhaust chamber 20: Energy storage system 30: Vehicle 40: Charging state control unit 41: Charging control unit 50:IS control unit 60: Engine

Claims

1. A valve-regulated lead-acid battery, A plurality of cells and a plurality of cell chambers each containing the plurality of cells, Each of the plurality of cells includes a positive electrode plate (except when the corners are chamfered), a negative electrode plate (except when the corners are chamfered), and an electrolyte; The plurality of cell chambers each have an exhaust valve independent of one another, the positive electrode plate comprises a positive electrode material; the negative electrode plate comprises a negative electrode material; the negative electrode material includes a carbonaceous material, The specific surface area (Sc) of the carbonaceous material measured by the BET method is Sc≧500 m ２ / g is satisfied, A valve-regulated lead-acid battery, wherein the content Cc of the carbonaceous material in the negative electrode material satisfies Cc≧0.5 mass%.

2. The specific surface area Sc is Sc≦1000 m ２ The valve-regulated lead-acid battery according to claim 1, wherein the valvular lead-acid battery satisfies the above formula (1).

3. The specific surface area Sc is Sc≧650 m ２ The valve-regulated lead-acid battery according to claim 1 or 2, wherein the valvular lead-acid battery satisfies the above formula (1).

4. The specific surface area Sc is Sc≧750 m ２ The valve-regulated lead-acid battery according to any one of claims 1 to 3, wherein the valvular lead-acid battery satisfies / g.

5. The regulated valve lead-acid battery according to any one of claims 1 to 4, wherein the content Cc satisfies Cc≦2.0 mass%.

6. The regulated valve lead-acid battery according to any one of claims 1 to 5, wherein the content Cc satisfies 0.75 mass%≦Cc≦1.75 mass%.

7. a valve-regulated lead-acid battery; a vehicle that receives a supply of power from the valve-regulated lead-acid battery; a state of charge control unit that controls a state of charge (SOC) of the valve-regulated lead-acid battery, The valve-regulated lead-acid battery includes a plurality of cells and a plurality of cell chambers that respectively accommodate the plurality of cells, Each of the plurality of cells includes a positive electrode plate (except when the corners are chamfered), a negative electrode plate (except when the corners are chamfered), and an electrolyte; The plurality of cell chambers each have an exhaust valve independent of each other, the negative electrode plate comprises a negative electrode material including a carbonaceous material, The specific surface area (Sc) of the carbonaceous material measured by the BET method is Sc≧500 m ２ / g is satisfied, the content Cc of the carbonaceous material in the negative electrode material satisfies Cc≧0.5% by mass, The vehicle is subjected to idling stop control when the SOC of the valve-regulated lead-acid battery is equal to or greater than a threshold of 90%, and is not subjected to idling stop control when the SOC of the valve-regulated lead-acid battery is less than the threshold.

8. The specific surface area Sc is Sc≦1000 m ２ The power storage system according to claim 7 , wherein the above formula (1) is satisfied.

9. The specific surface area Sc is Sc≧650 m ２ The power storage system according to claim 7 or 8, wherein the above-mentioned formula (1) is satisfied.

10. The specific surface area Sc is Sc≧750 m ２ The power storage system according to any one of claims 7 to 9, wherein / g is satisfied.

11. The power storage system according to any one of claims 7 to 10, wherein the content Cc satisfies Cc≦2.0 mass%.

12. The power storage system according to any one of claims 7 to 11, wherein the content Cc satisfies 0.75 mass%≦Cc≦1.75 mass%.

13. The storage system according to any one of claims 7 to 12, wherein the charge state control unit charges the valve-regulated lead-acid battery at a constant voltage when the SOC of the valve-regulated lead-acid battery is less than the threshold value.

14. The power storage system according to claim 13 , wherein the charging at the constant voltage is performed at 2.39 V / cell or more and 2.45 V / cell or less.

15. The power storage system according to any one of claims 7 to 14, wherein the vehicle is a small mobility vehicle.

Images