JP6153071B2 - Control valve type lead acid battery - Google Patents

Description

  The present invention relates to a control valve type lead acid battery, and more particularly to a control valve type lead acid battery containing a large amount of carbon black in a negative electrode material.

  The use of lead-acid batteries in an incompletely charged state improves the energy efficiency of automobiles. For example, in an idling stop vehicle, the fuel consumption is reduced by stopping the engine each time the vehicle is stopped, and the engine is started with the electric power from the storage battery when starting. For this reason, the storage battery is used in a state of insufficient charge. Not only idling stop cars, but charging to storage batteries is avoided to improve energy efficiency, and more power is taken out from the storage batteries, so the storage batteries are often placed in a state of insufficient charging.

  When a lead storage battery is used in a state of insufficient charge, lead sulfate, which is difficult to reduce, accumulates in the negative electrode material, and durability is reduced. It is known that accumulation of lead sulfate can be suppressed by containing a large amount of carbon black in the negative electrode material. However, when carbon black is contained in an amount exceeding, for example, 0.5 mass% with respect to 100 mass% of the spongy lead of the negative electrode material, the carbon black flows out from the negative electrode material during use.

  Patent document 1 (Unexamined-Japanese-Patent No. 2003-338285) is disclosing containing the bisphenol-type condensate and carbon black in the negative electrode material of a control valve type lead acid battery. The bisphenol-based condensate refines the negative electrode material and improves the charge acceptance by synergistic action with carbon black. However, according to the inventors' experiments, the negative electrode material paste containing a bisphenol-based condensate and a large amount of carbon black has a low penetration, making it difficult to fill the negative electrode current collector. Further, when carbon black penetrates into a separator such as a glass mat, it causes a short circuit. Therefore, it is necessary to develop a control valve type lead-acid battery that has a small amount of carbon permeating into the separator, can be easily filled with paste into the negative electrode current collector, and has excellent durability in a state of insufficient charge.

JP2003-338285

  The basic problems of the present invention are that the current collector is easily filled with paste, is excellent in low-temperature high-rate discharge performance, regenerative charge acceptance performance, excellent durability in a state of insufficient charge, and carbon to the separator The purpose of the present invention is to provide a control valve-type lead-acid battery that has a low penetration.

The valve-regulated lead-acid battery of the present invention comprises carbon, a bisphenol-based condensate having a sulfonic acid group, at least one of alginic acid or an alkali metal salt thereof, and spongy lead, and lead dioxide. A positive electrode material as a main component, and a separator that holds sulfuric acid in a state in which fluidity is limited, and the negative electrode material contains carbon at 0.5 mass% or more and 2.5 mass% at a content per 100 mass% of spongy lead Not more than 0.1%, bisphenol-based condensate having a sulfonic acid group is not less than 0.1 mass% and not more than 0.9 mass%, containing at least one of alginic acid or an alkali metal salt thereof in a total of not less than 0.05 mass% and not more than 0.3 mass%, and the negative electrode material is , Not containing polyglutamic acid and its salt, not containing olefinic polycarboxylic acid and its salt, or containing 0.3 mass% or less per 100 mass% of spongy lead The

  If a large amount of carbon is simply contained in the negative electrode material, the outflow of carbon from the negative electrode plate is significant, which causes carbon to penetrate into the separator and cause a short circuit. On the other hand, when the negative electrode material contains a bisphenol-based condensate and alginic acid or a salt thereof, the outflow of carbon can be suppressed and an infiltration short circuit in the separator can be suppressed. Furthermore, when alginic acid or a salt thereof is contained in the negative electrode material, the penetration into the negative electrode material paste increases, and the filling into the negative electrode current collector becomes easy. Using negative electrode materials containing carbon, bisphenol-based condensate, and alginic acid or its salt, in addition to the above effects, excellent low-temperature high-rate discharge performance and regenerative charge acceptance performance, as well as durability in a state of insufficient charge A control valve type lead-acid battery is obtained.

  In addition to the negative electrode material, the positive electrode material, and the separator, the control valve type lead storage battery includes, for example, a negative electrode current collector such as a negative electrode grid, a positive electrode current collector such as a positive electrode grid, a battery case, and a control valve. . The negative electrode material is held by a negative electrode current collector to form a negative electrode plate, and the positive electrode material is held by the positive electrode current collector to form a positive electrode plate. Further, a portion obtained by removing the current collector from the electrode plate, that is, the active material and its additive are referred to as electrode materials such as a negative electrode material and a positive electrode material.

  The sulfuric acid in the separator may contain alkali metal ions such as sodium and lithium, or aluminum ions. Further, silica may be contained in the sulfuric acid of the separator or in the electrode plate.

  The separator is, for example, a porous glass fiber separator, in particular, a mat-shaped glass fiber separator for a control valve type lead-acid battery, but may be a separator that gels and holds sulfuric acid with a gelling agent such as silica. That is, the separator may be a separator that holds sulfuric acid in a state where the fluidity is lowered.

The bisphenol-based condensate is, for example, a water-soluble polymer having a sulfonic acid group, but the type of substituent and the solubility in water are arbitrary. Bisphenol-based condensates are, for example, (-(OH) (RSO ₃ H) Ph-X-Ph (OH) (R'SO ₃ H) CH _2- ) _n
Wherein R and R ′ are appropriate alkyl groups such as a methylene group, X is an SO ₂ group, an alkyl group, etc., and two phenyl groups may be directly bonded without containing X. . In addition, hydrogen such as SO ₃ H group may be substituted with an appropriate cation such as Na ⁺ ion, particularly alkali metal ion, in the negative electrode material.

RSO ₃ H group, R′SO ₃ H group, CH ₂ group and the like are in an ortho position with respect to the OH group of the phenyl group (Ph), and the monomers of the condensate are connected to each other through the CH ₂ group. . Although many commercially available bisphenol-based condensates have two sulfonic acid groups per monomer, the number of sulfonic acid groups per monomer is arbitrary, such as 1 to 4. When X is SO ₂ group, bisphenol S is used, and when X is —C (CH ₃ ) ₂ —, bisphenol A is used. In the examples, bisphenol S is used. is there. The molecular weight of the bisphenol-based condensate is arbitrary, for example, about 4,000 to 250,000, and the influence of the molecular weight is small. A bisphenol-based condensate is similar to lignin sulfonic acid in that it is a polymer containing an aromatic ring, but does not have a carboxy group, an ether group, or an alcoholic hydroxyl group, and is not a network but a straight chain. The difference is that it is a polymer.

  The content of carbon, bisphenol-based condensate, alginic acid or a salt thereof, etc. in the negative electrode material indicates sponge-like lead as 100 mass%. When the negative electrode material contains lead sulfate or the like, the amount of spongy lead is determined by converting lead sulfate or the like into spongy lead. The amount of the content in the negative electrode material is, for example, the content at the stage of chemical conversion. Chemical conversion is a process in which basic lead sulfate and lead oxide are oxidized in an aqueous sulfuric acid solution to form lead dioxide as a positive electrode material, and are also reduced in a sulfuric acid aqueous solution to form sponge-like lead material in the negative electrode material.

  Preferably, the negative electrode material further contains an olefinic polycarboxylic acid or a salt thereof. Examples of olefinic polycarboxylic acids include polyacrylic acid, polymethacrylic acid, polymaleic acid and the like, and these are compounds in which hydrogen of a polyolefin skeleton such as polyethylene and polypropylene is substituted with a carboxyl group. Preferably, the olefinic polycarboxylic acid is polyacrylic acid or a salt thereof, or polymethacrylic acid or a salt thereof. Polyacrylic acid and polymethacrylic acid are substances having very similar chemical properties, and even if polyacrylic acid and its salt are replaced with polymethacrylic acid and its salt, the results are the same. The polycarboxylate is preferably a water-soluble alkali metal salt.

  Olefinic polycarboxylic acids such as polyacrylic acid, polymethacrylic acid and polymaleic acid can be block copolymerized with polyolefins such as polyethylene and polypropylene. In the copolymer containing polycarboxylic acid such as polyacrylic acid, it is actually a block of polycarboxylic acid, so if the mass of the copolymer is M and the mass of the block of polycarboxylic acid is m, The content of the copolymer multiplied by m / M is taken as the polycarboxylic acid content. The olefinic polycarboxylic acid salt is, for example, an alkali metal salt such as a lithium salt, a sodium salt, or a potassium salt, and is considered to exist mainly in the acid form in the negative electrode material because it is a strongly acidic bisphenol condensate.

  The content of the bisphenol-based condensate is preferably 0.1 mass% or more per 100 mass% of spongy lead. For example, 0.05 mass% has a small effect of suppressing the outflow of carbon. Further, since the carbon outflow amount is minimum at around 0.9 mass% for the bisphenol-based condensate, the content is preferably 0.9 mass% or less. The content of the bisphenol-based condensate is particularly preferably 0.1 mass% or more and 0.9 mass% or less.

  Alginic acid or a salt thereof lowers the penetration to a practical range with a content of 0.05 mass% or more per 100 mass% of spongy lead, and the content is preferably 0.05 mass% or more. If the content exceeds 0.3 mass%, adverse effects such as reduction in regenerative charge acceptance performance occur, and therefore the content is particularly preferably 0.05 mass% or more and 0.3 mass% or less. Alginic acid salts are preferably alkali metal salts, and insoluble calcium salts are less effective.

  Polyacrylic acid, polymethacrylic acid or their salts further reduce the outflow of carbon and are effective even at 0.005 mass% per 100 mass% of spongy lead, but the effect becomes remarkable at 0.01 mass% or more. When the content exceeds 0.3 mass%, adverse effects such as a decrease in regenerative charge acceptance performance occur, so the content is preferably 0.01 mass% or more, and particularly preferably 0.01 mass% or more and 0.3 mass% or less.

  The carbon may be graphite, carbon fiber, amorphous carbon such as soot, etc., but is preferably carbon black that is fine and has a large specific surface area. The carbon content of carbon black and other carbon containing 0.5 mass% or more per 100 mass% of spongy lead improves low-temperature high-rate discharge performance, regenerative charge acceptance performance, durability under insufficient charge, etc. If it is contained in excess of%, it becomes difficult to suppress the outflow of carbon. The carbon content is preferably 0.5 mass% or more, particularly preferably 0.5 mass% or more and 2.5 mass% or less.

  Hereinafter, an optimum embodiment of the present invention will be described. In carrying out the present invention, the embodiments can be appropriately changed in accordance with common sense of those skilled in the art and disclosure of prior art.

  Sodium alginate (molecular weight about 250,000) and sodium polyacrylate (molecular weight about 2,500,000) were dissolved in water, and carbon black was added and kneaded. To this, a bisphenol S condensate (with a molecular weight of about 100,000), 0.6 mass% barium sulfate for 100 mass% of spongy lead, and 0.1 mass% synthetic fiber reinforcing material were added and kneaded again, and carbon paste It was. The carbon paste was kneaded by adding a lead powder obtained by a ball mill method, 0.2 mass% lignin, water and sulfuric acid to 100 mass% of spongy lead to obtain a negative electrode material paste. The type of carbon black was arbitrary such as ketjen black, acetylene black, oil furnace black, etc. The results were almost the same even if the type of carbon black was changed. In addition, almost the same result was obtained when bisphenol A condensate was used instead of bisphenol S condensate. The results were the same whether the molecular weight of the bisphenol S condensate was changed to 10,000 or the molecular weight of sodium polyacrylate was changed to 5,000,000. Further, the reinforcing material, barium sulfate and lignin may not be added. The type and manufacturing method of the lead powder and the type and manufacturing method of the current collector such as a grid are arbitrary. Alginic acid and polyacrylic acid may be added as lithium salt, potassium salt or the like, or may be added in acid form. Furthermore, the order which adds each component is arbitrary.

  Negative electrode material pastes having compositions shown in Tables 1 and 2 were prepared by changing the contents of sodium alginate, sodium polyacrylate, carbon black, and bisphenol S condensate. The contents of alginic acid and polyacrylic acid are expressed as sodium salts. An expanded type Pb—Ca—Sn alloy negative electrode lattice was filled with a negative electrode material paste to obtain an unformed negative electrode plate. The penetration of each negative electrode material paste was measured with a penetration meter in accordance with JIS K 2207. The penetration represents the ease with which the negative electrode material paste is filled into the negative electrode lattice.

  Kneaded with 100 mass% lead powder manufactured by the ball mill method, 0.1 mass% synthetic fiber reinforcement, water and sulfuric acid, and filled in the positive type Pb-Ca-Sn alloy positive electrode lattice, unformed A positive electrode plate was obtained. A part of the lead powder may be used as a lead, and an additive composed of tin and barium may be added.

  As the separator, a mat-like and porous glass fiber separator for a control valve type lead-acid battery was used. However, other separators that hold sulfuric acid in a state in which fluidity is limited, such as silica gel impregnated with sulfuric acid, may be used. .

  An unformed positive electrode plate, unformed negative electrode plate, and separator are set in a battery case under pressure, sulfuric acid is injected to form a battery case, and a control valve type lead acid battery (electrolyte after formation) Specific gravity was 1.3). The storage battery has two positive plates and one negative plate for measuring initial performance (carbon outflow, low-temperature high-rate discharge performance, regenerative charge acceptance performance), a 20 hR capacity of 11 Ah, and a positive electrode for measuring durability performance. There were 7 plates and 8 negative plates, and the 20 hR capacity was 72 Ah.

  A negative electrode material that does not contain bisphenol-based condensate, binder such as polyacrylic acid, alginic acid, etc., and contains only carbon black, repeats a cycle of 0.1 CA × 5 h discharge and 0.1 CA × 10 h charge. A charge cycle test was conducted. The storage battery was disassembled at a predetermined number of cycles (common among samples), the amount of carbon in the negative electrode material was measured, and the amount of decrease from the initial content was measured to obtain the carbon outflow. The disassembled storage battery was observed for the presence of an osmotic short circuit penetrating the separator, and if there was a storage battery before disassembly that had an output voltage lowered to around 0 V, it was determined that there was an osmotic short circuit.

  Table 1 shows the presence or absence of osmotic short-circuiting and the outflow amount of carbon. When neither a bisphenol-based condensate nor a binder such as polyacrylic acid or alginic acid was contained, an osmotic short circuit occurred at a carbon black concentration of 0.7 mass% or more.

  A storage battery using a negative electrode material paste to which bisphenol-based condensate, polyacrylic acid sodium salt, polyglutamic acid sodium salt, sodium alginate, calcium alginate, or the like was added was prepared. For these storage batteries, the penetration, carbon outflow amount, and the presence or absence of permeation short circuit were measured in the same manner as in Table 1. As the low-temperature high-rate discharge performance, discharge was performed at 37.5 A at -15 ° C., and the discharge time until the terminal voltage reached 1.0 V was measured. As regenerative charge acceptance performance, the battery was charged for 10 seconds with a constant voltage charge of 2.4V (maximum current 12.5A) from a state with a charge rate of 90%, and the amount of charge was measured. Endurance performance in the state of insufficient charging is a cycle consisting of discharging at 50A for 60 seconds and constant voltage charging at 2.33A for 60 seconds (maximum current 50A), and the terminal voltage at the time of discharging is less than 1.0V. The number of cycles until was measured.

  The results are shown in Table 2 as relative values with Sample 1 as 100%. The carbon outflow amount is preferably 180% or less, and the low-temperature high-rate discharge performance, the regenerative charge acceptance performance, and the durability performance described above are preferably 100% or more. The penetration into the paste is preferably 50 or more.

  It can be seen that by containing a bisphenol-based condensate, the amount of carbon outflow can be suppressed, and the effect is remarkable at 0.1 mass% or more, and maximum at about 0.9 mass%. It can be seen that sodium alginate increases the penetration, and when it is contained at 0.35 mass%, the regenerative charge acceptance performance decreases. In addition, it is understood that calcium alginate has a low penetration and that a salt of alginic acid is preferably a water-soluble salt. Polyacrylic acid reduces the amount of carbon outflow, but lowering the penetration and containing more than 0.3 mass% is not preferable because it reduces regenerative charge acceptance performance. Moreover, when polyacrylic acid is changed to polyglutamic acid, the amount of carbon outflow increases, which is not preferable.

As described above, in the embodiment,
・ While maintaining the filling property of the negative electrode material paste,
・ Decrease penetration short circuit,
・ Keep low-temperature high-rate discharge performance and regenerative charge acceptance performance at or above the conventional level,
・ Moreover, the durability performance under conditions of insufficient charging could be improved.

Claims (4)

A negative electrode material containing carbon, a bisphenol-based condensate having a sulfonic acid group, at least one of alginic acid or an alkali metal salt thereof, and spongy lead; a positive electrode material mainly composed of lead dioxide; and fluidity A separator that holds sulfuric acid in a restricted state,
The negative electrode material is a content per 100 mass% of spongy lead, carbon is 0.5 mass% to 2.5 mass%, bisphenol-based condensate having a sulfonic acid group is 0.1 mass% to 0.9 mass%, alginic acid or its alkali At least one of the metal salts is contained in a total of 0.05 mass% to 0.3 mass%, and the negative electrode material does not contain polyglutamic acid and its salt, does not contain olefinic polycarboxylic acid and its salt, or is spongy A control valve type lead acid battery characterized by containing 0.3 mass% or less per 100 mass% of lead.   The control valve type lead acid battery according to claim 1, wherein the separator is a porous glass fiber separator.   The control valve-type lead acid battery according to claim 1 or 2, wherein the negative electrode material further contains 0.005 mass% or more and 0.3 mass% or less of olefinic polycarboxylic acid or a salt thereof per 100 mass% of spongy lead.   4. The valve-regulated lead-acid battery according to claim 3, wherein the olefinic polycarboxylic acid or a salt thereof is polyacrylic acid, polymethacrylic acid, or a salt thereof.