JP2017162754A - Electrode for lead-acid battery and lead-acid battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode for a lead-acid battery and a lead-acid battery, which have a long cycle life even if charging and discharging are performed at a high current density.SOLUTION: An electrode for a lead-acid battery includes a porous carbon material and lead or a lead compound complexed therein, the porous carbon material having a bicontinuous porous structure portion where a carbon portion and a gap form continuous structures, respectively.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lead storage battery electrode and a lead storage battery using the same.

  Lead storage batteries are used in a wide range of fields such as automobile power supplies and uninterruptible power supplies because they can easily extract large currents and are inexpensive.

  However, when charging / discharging is repeated at a particularly high current density, a phenomenon called sulfation in which lead sulfate crystals are deposited on the surface of the electrode occurs, resulting in a problem that the battery capacity decreases, that is, the cycle life decreases.

  Therefore, for example, Patent Document 1 discloses an attempt to extend the cycle life by adding activated carbon to the electrode material. According to Patent Document 1, the addition of activated carbon inhibits lead sulfate crystal growth on the electrode surface, and the large surface area of activated carbon increases the supply of lead ions, thereby improving cycle life characteristics. ing.

JP 2011-70870 A

  However, in lead-acid batteries, further improvement in cycle life characteristics is an issue, and in particular, charging and discharging at a high current density is carried out for the practical application of electric vehicles that use electric power as power, such as electric vehicles and fuel cell vehicles. However, there is a need for a lead-acid battery with little battery capacity reduction. This invention makes it a subject to provide the electrode for lead acid batteries and lead acid battery which have a long cycle life, even if it charges / discharges with high current density.

  In order to solve the above problems, the present invention provides an electrode for a lead storage battery in which a porous carbon material having a co-continuous porous structure portion in which a carbon portion and a void each form a continuous structure and lead or a lead compound are combined. It is.

  By using the lead-acid battery electrode of the present invention, it is possible to provide a lead-acid battery having a long cycle life even when charging / discharging at a high current density.

It is a scanning electron micrograph of the co-continuous porous structure part of the porous carbon material used for the electrode for lead acid batteries of this invention.

<Electrode for lead acid battery>
The lead-acid battery electrode of the present invention (hereinafter sometimes simply referred to as “electrode”) is a porous carbon material having a co-continuous porous structure portion (hereinafter simply referred to as “porous carbon material”). Is sometimes combined).

  In the present invention, any conventionally known lead or lead compound can be used without any particular limitation. The lead compound is a general term for compounds having lead as a constituent element, and lead oxides such as lead monoxide, lead dioxide, trilead tetroxide, and lead sulfate are preferably used. The lead-acid battery electrode may contain a plurality of these lead compounds.

  In order to exhibit sufficient performance as an electrode for a lead storage battery, the content of the lead element in the lead storage battery electrode is preferably 60% by weight or more. The higher the lead content, the higher the battery capacity. However, the lower the lead content, the easier it is to increase the surface area, which is advantageous for rapid charge / discharge. For this reason, the content of the lead element in the lead-acid battery electrode is more preferably 60% by weight to 95% by weight, and still more preferably 65% by weight to 90% by weight.

  When the lead storage battery electrode of the present invention is used for the negative electrode, the lead content is preferably 60% by weight or more. The more lead as the electrode active material, the higher the battery capacity. If the lead content is relatively small, the effect of the porous carbon material can be increased. Therefore, the lead content is preferably in the range of 60 to 98% by weight, and more preferably in the range of 60 to 90% by weight.

  Moreover, when using the electrode for lead acid batteries of this invention for an anode, it is preferable that content of a lead compound is 60 weight% or more. The more lead compound as the electrode active material, the higher the battery capacity. Moreover, when the content of the lead compound is relatively small, the effect of including the porous carbon material can be increased. Accordingly, the content of the lead compound is preferably in the range of 60 to 98% by weight, and more preferably in the range of 60 to 90% by weight. In particular, as the lead compound, lead dioxide that is directly involved in the electrochemical reaction and has the effect of increasing the battery capacity is particularly preferable.

  In the electrode of the present invention, the aspect of compounding the lead or lead compound and the porous carbon material is not particularly limited as long as at least a part of the lead or lead compound and the porous carbon material is in contact with the electrode. Absent. For example, the porous carbon material is concentrated on the surface of the electrode, is centrally disposed on the center of the electrode, is disposed in layers in the electrode, or is porous in a lattice shape. The part with a high abundance ratio of a carbonaceous material and the part with a low may be arrange | positioned alternately.

  In the electrode of the present invention, a part of lead or a lead compound is in a state where it penetrates into the voids of the co-continuous porous structure of the porous carbon material described later, the surface of the porous carbon material having high conductivity In addition to being able to charge and discharge efficiently due to the proximity of lead or lead compounds, it is possible to prevent the lead sulfate crystals in the charge and discharge reaction from becoming coarse, thus reducing cycle life. Since the effect to improve can also be anticipated, it is preferable. The amount of lead or lead compound penetrating into the co-continuous porous structure is not particularly limited. However, when the amount is 90% by volume or less with respect to the volume of the voids of the co-continuous porous structure, the electrolyte solution is sufficiently permeated. And since the effect mentioned above can be exhibited, it is preferable. The amount of lead or lead compound penetrating into the void is determined by identifying the carbon portion, void portion, lead or lead compound portion by elemental analysis when measuring the average porosity of the porous carbon material described later. The ratio is obtained by dividing the area of the lead compound portion by the sum of the area of the void portion and the area of the lead or lead compound portion.

  As the porous carbon material, a particulate, fibrous or film-like material is preferably used.

  In this specification, the “particulate porous carbon material” refers to a porous carbon material having an average particle diameter of 10 nm to 10 mm, and is not limited to a substantially spherical material, but a short fiber shape, a flake shape, a lump shape, or a rod shape. Etc., and materials having irregular shapes are also included. For example, a fibrous porous carbon material crushed or cut, or a scale-like porous carbon material obtained by crushing a film-like porous carbon material having an average particle diameter in the above range is In the invention, it is regarded as “particulate porous carbon material”.

  The particle diameter is determined by observing the porous carbon material with a scanning electron microscope, measuring the length of the longest part (major axis) and the length of the shortest part (minor axis) of each particle, (major axis + minor axis) It is a numerical value obtained by / 2. In this invention, let the average value of the particle diameter measured about 50 porous carbon materials at random be the average particle diameter of a porous carbon material. In addition, the particle diameter and average particle diameter of the porous carbon material present in the electrode were determined by observing the cross section of the electrode formed by the cross section polisher method (CP method) with a scanning electron microscope. The minimum unit size can be measured by the same method as described above.

  It is particularly preferable to use a particulate porous carbon material because, in the electrode manufacturing process, a conventional electrode manufacturing process including activated carbon can be applied as it is, and distortion can be eliminated between particles even when bending, pulling or compression occurs. .

  When a particulate porous carbon material is used, if the average particle size is 10 μm or less, for example, a very smooth solid can be obtained as a solid component for forming a coating solution. It is possible to prevent defects such as liquid peeling and cracking, which is preferable. On the other hand, when the thickness is 0.1 μm or more, a sufficient surface area can be secured for the particles, a reaction interface can be sufficiently obtained when combined with lead or lead oxide, and charge / discharge characteristics can be improved.

  When the particulate porous carbon material is used, it is preferable that the porous carbon material is dispersed in a matrix made of lead or a lead compound. In this case, the particulate porous carbon material is preferably contained in an amount of 2 to 50% by weight with respect to lead or a lead compound.

  In addition, when the layer containing the particulate porous carbon material is formed on the surface of the molded body made of lead or a lead compound, ions are adsorbed on the porous carbon material at the initial stage of charge and discharge, so that The formation of multiple layers is advantageous for high-speed charge / discharge, and the presence of porous carbon material on the surface where lead crystallization is likely to proceed during discharge prevents the formation of large crystals and prolongs the service life. Is preferable because it becomes possible.

  In the present specification, the “fibrous porous carbon material” means that the average value of the aspect ratio calculated from the diameter converted as a circle having the same area from the cross-sectional area of the fiber and the fiber length is 100 or more. Refers to things. In addition, it is considered that what is fibrous and whose particle diameter measured by the said method is 10 nm-10 mm is both fibrous and particulate. In the present invention, an average value measured for 50 porous carbon materials at random is used as an average aspect ratio of the porous carbon material.

  In the case of using a fibrous porous carbon material, it is preferable that the porous carbon material is formed into a woven or non-woven fabric and then combined with lead or a lead compound. In addition, short fibers of 10 mm or less, which can be regarded as particulate porous carbon material as described above, include an embodiment in which the porous carbon material is dispersed in a matrix made of lead or a lead compound, or porous carbon material. It is also preferable that the layer containing the material is used in a form formed on the surface of a molded body made of lead or a lead compound.

  The “film-like porous carbon material” means a material formed into a flat plate having a thickness of 1000 μm or less.

  A woven or non-woven fabric having a thickness of 1000 μm or less formed from a fibrous porous carbon material, or the above-described film-like porous carbon material (hereinafter referred to as “sheet-like porous carbon material” in the present specification) In the case where the sheet-like porous carbon material is used, an embodiment in which the sheet-like porous carbon material is laminated with a layer made of lead or a lead compound is preferable. The sheet-like porous carbon material may be a single sheet or a plurality of sheets. In the case where a plurality of sheet-like porous carbon materials are used, an electrolyte is formed in the form in which a porous carbon material layer and a layer made of lead or a lead compound are sequentially laminated in the thickness direction of the lead storage battery electrode. It is preferable because both movement and conductivity can be made compatible.

  In addition, when a sheet-like porous carbon material is joined to the surface of a molded body made of lead or a lead compound, an electric double layer is formed by adsorption of ions to the porous carbon material at the initial stage of charge and discharge. Therefore, it is advantageous for high-speed charge / discharge, and the presence of a porous carbon material on the surface where lead crystallization is likely to proceed during discharge can prevent the formation of large crystals and extend the life. This is preferable.

  Moreover, the aspect by which the matrix which consists of lead or a lead compound is filled with the space | gap part of the woven fabric or nonwoven fabric formed from the fibrous porous carbon material is also preferable. The filling rate at this time is calculated | required by dividing the area of the part which is a lead or a lead compound among the cross sections of the electrode formed by the cross section polisher method by the observed cross-sectional area. The higher the filling rate, the higher the capacity, and the lower the filling rate, the more easily the effect of the porous carbon material of the present invention can be achieved, which is advantageous for high-speed charging / discharging. The filling rate is preferably in the range of 10 to 90% by volume, since the above-described object can be achieved, and more preferably in the range of 20 to 80% by volume.

  Moreover, the electrode for lead acid batteries of this invention can contain a conductive support agent, a binder, a metal, a metal compound, etc. other than a porous carbon material and lead or a lead compound.

  Examples of the conductive aid include carbon black, carbon nanotubes, carbon nanowhiskers, graphene and the like, and these may be used alone or in combination. The more conductive auxiliary, the lower the resistance of the lead-acid battery electrode, which is advantageous for charging / discharging with a large current, and the smaller the conductive auxiliary, the higher the ratio of lead or lead compound as the active material in the lead-acid battery electrode, the higher Capacity can be obtained. For these reasons, the conductive assistant is preferably 10% by weight or less, and more preferably in the range of 0.5 to 8% by weight.

  In addition, a conventionally known polymer material can be used as the binder, and a material excellent in acid resistance is particularly preferable. Materials used for such binders include polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxyethyl cellulose, polyethylene oxide, ethylene propylene rubber. And styrene butadiene rubber, chlorosulfonated polyethylene rubber, nitrile rubber, methyl methacrylate butadiene rubber, butyl glycol acetate, and ethyl diglycol acetate.

  The higher the content of the binder, the more stable the form of the lead-acid battery electrode, and even when charging and discharging are repeated, the electrode material can be prevented from falling off, so that the durability can be improved. Further, the smaller the binder, the higher the ratio of lead or lead compound as an active material in the lead-acid battery electrode, and a higher capacity can be obtained. Accordingly, the binder content is preferably 10% by weight or less, and more preferably in the range of 0.5 to 8% by weight.

  The lead-acid battery electrode of the present invention is 5% by weight or less of an alkali metal, an alkaline earth metal, a transition metal, and a metal compound containing these for the purpose of enhancing the object and effect of the present invention by utilizing catalytic action or the like. It may be included.

  Furthermore, the lead-acid battery electrode of the present invention is preferably combined with a current collector. Conventionally known materials can be used as the current collector, and examples thereof include carbon, aluminum, stainless steel, copper, nickel, lead and the like. Among them, a current collector using lead is preferable because it has a high affinity with the material constituting the electrode, and can stably perform an electrochemical reaction without mixing foreign metal ions in the electrolyte solution. . The shape of the current collector is not particularly limited, and examples thereof include a film shape and a lattice shape.

  When the current collector is in the form of a film, it is preferable that irregularities are formed on the surface combined with the electrode. The film-like current collector on which the irregularities are formed has a large contact area with the lead-acid battery electrode, and the effect of reducing the contact resistance is obtained. The rougher the unevenness, the larger the contact area, and the finer the unevenness, the higher the strength of the current collector. From this, the irregularities preferably have an arithmetic average roughness Ra of 1 μm or more, more preferably in the range of 2 to 50 μm, and even more preferably in the range of 2 to 10 μm.

  When the current collector is in a lattice shape, even if it is a net shape made of metal, a fibrous metal wire or carbon fiber is used in the form of a fabric such as a woven fabric, a knitted fabric, a braided fabric or a non-woven fabric. It does not matter.

  The thickness of the lead-acid battery electrode is not particularly limited and can be appropriately changed according to desired characteristics. However, the thicker the lead-acid battery, the smaller the number of stacks. The density can be increased to increase the electric capacity, and the thinner the thickness, the lower the resistance of the electrode and the faster charge / discharge becomes possible. The range of the electrode thickness can be arbitrarily designed in the range of 1 μm to 10 mm.

[Porous carbon material]
The porous carbon material used for the lead-acid battery electrode of the present invention has a co-continuous porous structure portion in which the carbon portion and the void each form a continuous structure. Specifically, for example, when the surface of particles obtained by crushing a sample sufficiently cooled in liquid nitrogen with tweezers or the like or pulverizing with a mortar or the like is observed with a scanning electron microscope (SEM) or the like. As shown in the scanning electron micrograph (FIG. 1) of the carbon material, the carbon portion and the void formed as a portion other than the carbon portion have a portion that is observed as a continuous and intertwined structure. .

  Electrodes using a porous carbon material having a co-continuous porous structure portion can be obtained by efficiently infiltrating electrolyte or lead or lead compound fine particles into the voids of the co-continuous porous structure portion in lead-acid battery applications. In addition, the contact area with the active material becomes very large, which can contribute to higher capacity. In addition, since the voids of the co-continuous porous structure are narrow and continuous with a curved surface, lead sulfate crystals cannot grow large and precipitate as aggregates of microcrystals, resulting in coarse particles that inhibit charge / discharge. The effect of minimizing sulfation due to crystallization of lead sulfate can be expected. In addition, since the electrolyte ions can move efficiently, the flow resistance of the electrolyte ions can be reduced, and high-speed charging / discharging is also possible. In addition, since the carbon portion is continuous, the electrical conductivity is increased and the internal resistance can be reduced, so that efficient charge and discharge can be performed. In addition, due to the effect of the carbon parts supporting each other in the structure, for example, a material having great resistance to deformation such as tension and compression during the manufacturing process and use can be obtained.

  Examples of the co-continuous porous structure include a lattice shape and a monolith shape, and are not particularly limited. However, a monolith shape is preferable in that the above effect can be exhibited. Monolithic form refers to a form in which the carbon part forms a three-dimensional network structure in a co-continuous porous structure, and is formed by removing aggregated and connected template particles, or a structure in which individual particles are aggregated and connected. A distinction is made between irregular structures such as those formed by open voids and surrounding skeletons.

  Further, the co-continuous porous structure portion of the porous carbon material preferably has a periodic structure. Having a periodic structure can be confirmed by the fact that X-rays are incident on the porous carbon material and the scattering intensity has a peak value.

  The structural period of the porous carbon material is preferably 0.002 μm to 20 μm. The structural period is calculated by the following formula from the scattering angle θ at a position where the X-ray is incident on the carbon material taken out from the electrode of the present invention and the scattering intensity has a peak value.

Structure period: L, λ: wavelength of incident X-rays However, there are cases where the structure period is large and scattering at a small angle cannot be observed. In that case, the structural period is obtained by X-ray computed tomography (X-ray CT). Specifically, after performing a Fourier transform on a three-dimensional image photographed by X-ray CT, the two-dimensional spectrum is averaged to obtain a one-dimensional spectrum. The characteristic wavelength corresponding to the position of the peak top in the one-dimensional spectrum is obtained, and the structural period is calculated from the reciprocal thereof.

  When the structural period of the co-continuous porous structure portion is 0.002 μm or more, the electrolytic solution easily enters the void portion, and the flow resistance can be reduced. In addition, it can be easily combined with lead or a lead compound as an active material. In addition, the effect of improving electrical conductivity due to the carbon portion is increased. The structural period is preferably 0.01 μm or more, and more preferably 0.1 μm or more. Further, when the structural period is 20 μm or less, excellent physical properties such as a high surface area, pressure resistance, and fracture toughness can be obtained. The structural period is preferably 10 μm or less, and more preferably 1 μm or less.

  In addition to having a uniform co-continuous porous structure, the flow resistance of the electrolyte can be reduced, and in all processes related to manufacturing such as the porous carbon material manufacturing process, electrode manufacturing process, device assembly process, etc., tension, compression, etc. It is possible to use a material having a great resistance to deformation. The uniformity of the co-continuous porous structure of the carbon material of the present invention can be determined by the half width of the peak of the scattering intensity when X-rays are incident on the carbon material of the present invention. The full width at half maximum of the X-ray scattering peak of the carbon material of the present invention is preferably 5 ° or less, more preferably 3 ° or less, and particularly preferably 1 ° or less. The half width of the peak in the present invention is the peak A at the point A, a straight line parallel to the vertical axis of the graph is drawn from the point A, and the intersection of the straight line and the spectrum baseline is the point B. This is the width of the peak at the midpoint (point C) of the line segment connecting points A and B. In addition, the width | variety of the peak said here is a width | variety on the straight line which is parallel to a base line and passes along the point C. FIG.

  In the analysis of the structural period by X-rays, the part having no co-continuous porous structure, which will be described later, has a structural period outside the above range, so the analysis is not affected and the structural period calculated by the above formula is used. Thus, the structure period of the co-continuous porous structure forming portion is used.

  The smaller the structure period, the finer the structure, the larger the surface area per unit volume or unit weight, and the higher the contact efficiency with the electrolyte, which can contribute to the improvement of charge / discharge efficiency at a large current. In addition, the larger the structural period, the lower the flow resistance of the electrolytic solution, and the efficient entry and exit of electrolyte ions can contribute to the expression of high rate characteristics. From these facts, the structural period of the co-continuous porous structure can be appropriately adjusted according to the intended characteristics and use conditions.

  The co-continuous porous structure part preferably has an average porosity of 10 to 80%. The average porosity is an enlargement ratio adjusted to be 1 ± 0.1 (nm / pixel) of a cross section in which an embedded sample is precisely formed by a cross section polisher method (CP method). The image is calculated by the following expression from an image observed at a resolution of at least a pixel, where the area of interest required for calculation is set in 512 pixels square, the area of the area of interest is A, and the area of the hole is B.

Average porosity (%) = B / A × 100
The higher the average porosity, the higher the filling efficiency when combined with lead or lead compounds as the active material, and the lower the pressure loss as the electrolyte flow path, the lower the resistance to compression and bending. In addition, it is advantageous because it is hardly broken even in handling, pressurization conditions, and volume change of the active material accompanying charge / discharge. Considering these, the average porosity of the co-continuous porous structure portion is preferably in the range of 15 to 75%, and more preferably in the range of 18 to 70%. In addition, lead or a lead compound may be contained in the voids of the co-continuous porous structure of the porous carbon material. However, elemental analysis is performed to exclude the influence of lead or the lead compound, and the average porosity is calculated.

  Furthermore, the porous carbon material having a co-continuous porous structure portion preferably has pores having an average diameter of 0.01 to 10 nm on the surface. The surface means not only the surface layer when the porous carbon material is viewed macroscopically but also the contact surface with any outside of the carbon material including the surface of the carbon portion in the co-continuous porous structure portion of the porous carbon material. . The pores can be formed on the surface of the carbon portion in the bicontinuous porous structure portion and / or in a dense portion that does not substantially have the bicontinuous porous structure described later, but at least the carbon portion in the portion having the bicontinuous porous structure. It is preferable to form on the surface. That is, as a preferred embodiment of the porous carbon material, there are pores having an average diameter of 0.01 to 10 nm different from the pores constituting the co-continuous porous structure and the pores constituting the co-continuous porous structure. It is done.

  The average diameter of such pores is preferably 0.01 nm or more, and more preferably 0.1 nm or more. Moreover, it is preferable that it is 5 nm or less, and it is more preferable that it is 2 nm or less. Since the average diameter of the pores is 0.01 nm to 10 nm, when lead sulfate is precipitated on the surface of the porous carbon material, the precipitation occurs in minute pores. The possibility of producing lead sulfate is low, and as a result, charge / discharge characteristics can be improved.

  The porous carbon material preferably has a pore volume analyzed by the MP method described later of 0.1 ml / g or more, more preferably 1.0 ml / g or more, and 1.5 ml / g. More preferably, it is the above. When the pore volume is 0.1 ml / g or more, the charge / discharge improvement effect is further improved. Although an upper limit is not specifically limited, if it is less than 10 ml / g, it can maintain the intensity | strength of a carbon material and can ensure handling property by making a bulk density into an appropriate range, and is preferable.

  In addition, in this specification, the average diameter of a pore means the measured value by any method of BJH method or MP method. That is, if either one of the measured values by the BJH method or the MP method falls within the range of 0.01 to 10 nm, it is determined that the surface has pores having an average diameter of 0.01 to 10 nm. The same applies to the preferable range of the pore diameter. The BJH method and the MP method are widely used as a pore size distribution analysis method, and can be obtained based on a desorption isotherm obtained by adsorbing and desorbing nitrogen on a porous carbon material. The BJH method is a method of analyzing the pore volume distribution with respect to the pore diameter assumed to be cylindrical according to the Barrett-Joyner-Halenda standard model, and can be applied mainly to pores having a diameter of 2 to 200 nm. (For details, see J. Amer. Chem. Soc., 73, 373, 1951 etc.). The MP method is based on the external surface area and adsorption layer thickness (corresponding to the pore radius because the pore shape is cylindrical) obtained from the change in the tangential slope at each point of the adsorption isotherm. This is a method for obtaining the pore volume and plotting it against the thickness of the adsorption layer to obtain a pore size distribution (for details, refer to Junealod Colloid and Interface Science, 26, 45, 1968, etc.). Applicable to pores having a diameter. In the present invention, all values obtained by rounding off the second decimal place to the first decimal place are used.

In a porous carbon material having a co-continuous porous structure portion, voids in the co-continuous porous structure portion may affect the pore size distribution and pore volume measured by the BJH method or the MP method. That is, there is a possibility that these measured values may be obtained as values that reflect not only the pores but also the presence of voids. Even in this case, the measured values obtained by these methods are used in the present invention. Assume that the average diameter and the pore volume of the pores. Moreover, if the pore volume measured by BJH method or MP method is less than 0.05 cm < ³ > / g, it will be judged that the pore is not formed in the material surface.

The porous carbon material preferably has a BET specific surface area of 5 m ² / g or more. The BET specific surface area is more preferably 20 m ² / g or more, further preferably 100 m ² / g or more, and further preferably 1000 m ² / g or more. When the BET specific surface area is 5 m ² / g or more, the area capable of acting on the adsorption and desorption of electrolyte ions is increased, and the performance as an electrode for a lead storage battery is improved. Although an upper limit is not specifically limited, The intensity | strength of a porous carbon material is hold | maintained as it is less than 4500 m < ² > / g, and handleability can be ensured by making a bulk density into an appropriate range. The BET specific surface area in the present invention can be calculated based on the BET equation by measuring the adsorption isotherm by adsorbing and desorbing nitrogen to and from the porous carbon material according to JISR 1626 (1996). it can.

  It is also a preferable aspect that the porous carbon material having a co-continuous porous structure part includes a dense part that does not substantially have a co-continuous porous structure (hereinafter, sometimes simply referred to as “dense part”). . The dense part substantially having no co-continuous porous structure is the resolution when a cross section formed by the cross section polisher method (CP method) is observed at an enlargement ratio of 1 ± 0.1 (nm / pixel). This means that a portion where a clear void is not observed due to the following is present in an area equal to or larger than a square region corresponding to three times the structural period L calculated from an X-ray described later.

  Since the dense portion is densely filled with carbon, the electron conductivity is high and the electrical resistance can be lowered. In addition, the presence of the dense portion can increase the resistance to compressive fracture that is received from the change in volume of the active material accompanying charging / discharging.

  The proportion of the dense part can be adjusted as appropriate. For example, when 5% by volume or more is a part that does not have a co-continuous porous structure, it is possible to maintain electrical conductivity and thermal conductivity at a high level. This is preferable.

  In the case where a particulate porous carbon material is used, if the above-described dense portion is present in a part of each particle, it is possible to increase electrical conductivity in the particle, and the particle itself. This is preferable because the compressive strength of the resin can be increased and performance deterioration under high pressure caused by the volume change associated with charge / discharge can be expected.

  Further, in the aspect in which the scaly particles obtained by pulverizing the film-like porous carbon material are dispersed in the electrode, the dense part is present in the scaly particles, so that there is a part having high strength, so-called Since the effect as a reinforcing material can be obtained, cracks and chips in the electrode handling and charge / discharge reactions can be prevented, and in addition to improving yield, durability can also be improved.

  Also, in the case of using a fibrous porous carbon material, the presence of a dense portion in the outer peripheral portion of the fiber can increase the strength of the fiber itself, resulting in deformation due to volume changes during handling or charge / discharge. It is preferable because it has proof strength and can prevent the electrode from falling off due to cracking or chipping. Further, the presence of the dense portion is effective in reducing the electric resistance with respect to the fiber axis direction or the fiber cross-sectional direction, which is also preferable in terms of enhancing the charge / discharge efficiency.

  In the case of using a film-like porous carbon material, it is preferable to use a film having a co-continuous porous structure portion in the inner layer and a dense portion in the outer layer on one side or both sides thereof. Such a film is preferable because the dense portion can maintain electrical conductivity at a high level and the dense portion can function as an interface suitable for adhesion to a metal foil used as a current collector. In this embodiment, the thickness of the dense portion is not particularly limited, but if it is too thick, the porosity and specific surface area tend to decrease as the porous carbon material. Therefore, the thickness is preferably 100 μm or less, and 50 μm. More preferably, it is more preferably 20 μm or less. Here, the lower limit is not particularly limited, but is preferably 0.01 μm or more from the viewpoint of maintaining the form of the material and exhibiting the function distinguished from the bicontinuous porous structure portion.

  In addition to the effect that the dense portion is formed on only one surface of the film, the contact resistance can be reduced when the dense portion is joined to the current collector, and the resistance of the lead-acid battery electrode can be lowered. Highly efficient electrode by mainly sharing the contact with lead or lead compound and / or electrolyte in the part with co-continuous porous structure, and reducing both contact resistance and improving charge / discharge reaction efficiency Is preferable.

<Lead battery>
The lead-acid battery can improve cycle life characteristics by using the lead-acid battery electrode of the present invention for at least one of the positive electrode and the negative electrode. However, the lead-acid battery electrode of the present invention can be used for both the positive electrode and the negative electrode. More preferred. Since the lead storage battery using the lead storage battery electrode of the present invention for the positive electrode and the negative electrode is excellent in charge / discharge characteristics at a large current, it is hardly deteriorated even if repeated charge / discharge is performed, and can be used for a long period of time.

  Since the lead battery using the electrode for the lead storage battery of the present invention has a high capacity and can be charged and discharged at high speed, for example, a fuel cell vehicle, a plug-in hybrid vehicle, a hybrid vehicle, an electric vehicle, a train, an aircraft, various home appliances. It is suitable for machine tools, motorcycles, forklifts, construction machines, etc. Further, it can be suitably used for renewable energy-related devices such as solar power generation, wind power generation, geothermal power generation, wave power generation, and power supply control bases, as well as backup power sources for hospitals, factories, data centers, and the like.

  In particular, in automobile applications such as fuel cell vehicles, plug-in hybrid vehicles, hybrid vehicles, electric vehicles, etc., the electric power generated by the motor when the brake is operated is instantly stored in the lead storage battery of the present invention, and this is started, etc. Can be supplied when a large driving force is required, and stable operation is possible by supplying electric power required by electrical components. Further, even in a conventional automobile equipped with an internal combustion engine, an automobile that performs idling stop frequently repeats stop and restart of the engine. Therefore, the lead storage battery of the present invention that is excellent in charge and discharge due to a large current at start-up It is suitable for use.

  In addition, the lead storage battery of the present invention can be suitably used for mounting on a train, taking advantage of high capacity, high-speed charging characteristics, and long life. A train equipped with the lead storage battery of the present invention is preferable because the regenerative power generation by the brake is charged to the lead storage battery of the present invention, so that traveling with energy saving becomes possible. In particular, even when there is a sudden fluctuation such as a voltage drop due to a lightning strike in the power supply from the overhead line, stable acceleration and deceleration can be performed, which is preferable because it can contribute to stable operation.

  Furthermore, the lead storage battery of the present invention is preferably combined with wind power generation or solar power generation. In wind power generation and solar power generation, the amount of power generation varies greatly with time due to fluctuations in wind power and sunshine. However, the high-speed charge / discharge characteristics of the lead storage battery of the present invention enable highly efficient power storage.

<Method for producing porous carbon material>
As an example, the porous carbon material used in the present invention is a state in which 10 to 90% by weight of a carbonizable resin and 90 to 10% by weight of a disappearing resin are mixed to form a resin mixture (step 1) and a compatible state. The resin mixture can be produced by a production method having a step (step 2) for phase separation and immobilization and a step (step 3) for carbonization by heating and baking.

[Step 1]
Step 1 is a step in which 10 to 90% by weight of the carbonizable resin and 90 to 10% by weight of the disappearing resin are compatible to form a resin mixture.

  Here, the carbonizable resin is a resin that is carbonized by firing and remains as a carbon material, and preferably has a carbonization yield of 40% or more. As the carbonizable resin, both a thermoplastic resin and a thermosetting resin can be used, and examples of the thermoplastic resin include polyphenylene oxide, polyvinyl alcohol, polyacrylonitrile, phenol resin, wholly aromatic polyester, Examples of thermosetting resins include unsaturated polyester resins, alkyd resins, melamine resins, urea resins, polyimide resins, diallyl phthalate resins, lignin resins, urethane resins, and the like. In view of cost and productivity, polyacrylonitrile and phenol resin are preferable, and polyacrylonitrile is more preferable. Particularly in the present invention, polyacrylonitrile is a preferred embodiment because a high specific surface area can be obtained. These may be used alone or in a mixed state. The carbonization yield here is the difference between the weight at room temperature and the weight at 800 ° C. by measuring the change in weight when the temperature is raised at 10 ° C./min in a nitrogen atmosphere by the thermogravimetry (TG) method. Is divided by the weight at room temperature.

  Further, the disappearing resin is a resin that can be removed after Step 2 described later, and is preferably a resin that can be removed at least in any stage of the infusibilization treatment, the infusibilization treatment, or the firing. . The removal rate is preferably 80% by weight or more, and more preferably 90% by weight or more when finally becoming a porous carbon material. The method of removing the disappearing resin is not particularly limited, and is a method of chemically removing the polymer by depolymerizing with a chemical, a method of removing the disappearing resin with a solvent, a method of heating and thermal decomposition. A method of removing the lost resin by reducing the molecular weight is preferably used. These methods can be used singly or in combination, and when implemented in combination, each may be performed simultaneously or separately.

  As a method of chemically removing, a method of hydrolyzing with an acid or an alkali is preferable from the viewpoints of economy and handleability. Examples of the resin that is susceptible to hydrolysis by acid or alkali include polyester, polycarbonate, and polyamide.

  As a method of removing the disappearing resin with a solvent that dissolves, the mixed carbonizable resin and the disappearing resin are continuously supplied with a solvent to dissolve and remove the disappearing resin, or mixed in a batch system. A suitable example is a method of dissolving and removing the lost resin.

  Specific examples of the disappearing resin suitable for the method of removing with a solvent include polyolefins such as polyethylene, polypropylene and polystyrene, acrylic resins, methacrylic resins, polyvinyl pyrrolidone, aliphatic polyesters, polycarbonates and the like. Among these, an amorphous resin is more preferable because of its solubility in a solvent, and examples thereof include polystyrene, methacrylic resin, polycarbonate, and polyvinylpyrrolidone.

  As a method of removing the lost resin by reducing the molecular weight by thermal decomposition, a method in which the mixed carbonizable resin and the lost resin are heated in a batch manner to thermally decompose, or a continuously mixed carbonized resin and the lost resin are removed. A method of heating and thermally decomposing while continuously supplying to a heat source.

  Among these, the disappearing resin is preferably a resin that disappears by thermal decomposition when carbonizing the carbonizable resin by firing in Step 3 described later, and is large during the infusibilization treatment of the carbonizable resin described later. A resin that does not cause a chemical change and has a carbonization yield after firing of less than 10% is preferable. Specific examples of such disappearing resins include polyolefins such as polyethylene, polypropylene, and polystyrene, acrylic resins, methacrylic resins, polyacetals, polyvinylpyrrolidones, aliphatic polyesters, aromatic polyesters, aliphatic polyamides, polycarbonates, and the like. These may be used alone or in a mixed state.

  In step 1, the carbonizable resin and the disappearing resin are mixed to form a resin mixture (polymer alloy). “Compatibilized” as used herein refers to creating a state in which the phase separation structure of the carbonizable resin and the disappearing resin is not observed with an optical microscope by appropriately selecting the temperature and / or solvent conditions.

  The carbonizable resin and the disappearing resin may be compatible by mixing only the resins, or may be compatible by adding a solvent or the like.

  A system in which a plurality of resins are compatible includes a phase diagram of an upper critical eutectic temperature (UCST) type that is in a phase separation state at a low temperature but has one phase at a high temperature, and conversely, a phase separation state at a high temperature. However, there is a system showing a lower critical solution temperature (LCST) type phase diagram that becomes one phase at a low temperature. In particular, when a system in which at least one of the carbonizable resin and the disappearing resin is dissolved in a solvent, those in which phase separation to be described later is induced by permeation of the non-solvent are also preferable examples.

  The solvent to be added is not particularly limited, but the absolute value of the difference between the average value of the solubility parameter (SP value) of the carbonizable resin and the disappearing resin, which is a solubility index, is within 5.0. It is preferable. Since it is known that the smaller the absolute value of the difference from the average value of the SP values, the higher the solubility, it is preferable that there is no difference. Further, the larger the absolute value of the difference from the average SP value, the lower the solubility, and it becomes difficult to take a compatible state between the carbonizable resin and the disappearing resin. Therefore, the absolute value of the difference from the average value of SP values is preferably 3.0 or less, and most preferably 2.0 or less.

  Specific examples of combinations of carbonizable resins and disappearance resins that are compatible are polyphenylene oxide / polystyrene, polyphenylene oxide / styrene-acrylonitrile copolymer, wholly aromatic polyester / polyethylene as long as they do not contain solvents. Examples include terephthalate, wholly aromatic polyester / polyethylene naphthalate, wholly aromatic polyester / polycarbonate. Specific examples of combinations of systems containing solvents include polyacrylonitrile / polyvinyl alcohol, polyacrylonitrile / polyvinylphenol, polyacrylonitrile / polyvinylpyrrolidone, polyacrylonitrile / polylactic acid, polyvinyl alcohol / vinyl acetate-vinyl alcohol copolymer, polyvinyl Examples thereof include alcohol / polyethylene glycol, polyvinyl alcohol / polypropylene glycol, and polyvinyl alcohol / starch.

  The method for mixing the carbonizable resin and the disappearing resin is not limited, and various known mixing methods can be adopted as long as they can be mixed uniformly. Specific examples include a rotary mixer having a stirring blade, a kneading extruder using a screw, and the like.

  It is also a preferred aspect that the temperature (mixing temperature) when mixing the carbonizable resin and the disappearing resin is equal to or higher than the temperature at which the carbonizable resin and the disappearing resin are both softened. Here, the softening temperature may be appropriately selected as the melting point if the carbonizable resin or disappearing resin is a crystalline polymer, and the glass transition temperature if it is an amorphous resin. By setting the mixing temperature to be equal to or higher than the temperature at which both the carbonizable resin and the disappearing resin are softened, the viscosity of the both can be lowered, so that more efficient stirring and mixing are possible. Although the upper limit of the mixing temperature is not particularly limited, it is preferably 400 ° C. or lower from the viewpoint of preventing deterioration of the resin due to thermal decomposition and obtaining a precursor of a porous carbon material having excellent quality.

  Further, in step 1, 90 to 10% by weight of the disappearing resin is mixed with 10 to 90% by weight of the carbonizable resin. It is preferable that the carbonizable resin and the disappearing resin are within the above-mentioned range since an optimum void size and void ratio can be arbitrarily designed. If the carbonizable resin is 10% by weight or more, it is possible to maintain the mechanical strength of the carbonized material and improve the yield. Further, if the carbonizable material is 90% by weight or less, it is preferable because the lost resin can efficiently form voids.

  The mixing ratio of the carbonizable resin and the disappearing resin can be arbitrarily selected within the above range in consideration of the compatibility of the respective materials. Specifically, in general, the compatibility between resins deteriorates as the composition ratio approaches 1: 1, so when a system that is not very compatible is selected as a raw material, the amount of carbonizable resin is increased. It can also be mentioned as a preferred embodiment that the compatibility is improved by approaching a so-called uneven composition, for example, by reducing it.

  It is also a preferred embodiment to add a solvent when mixing the carbonizable resin and the disappearing resin. Addition of a solvent lowers the viscosity of the carbonizable resin and the disappearing resin to facilitate molding, and facilitates compatibilization of the carbonizable resin and the disappearing resin. The solvent here is not particularly limited as long as it is a liquid at room temperature that can dissolve and swell at least one of carbonizable resin and disappearing resin. Any resin that dissolves the resin is more preferable because the compatibility between the two can be improved.

  The addition amount of the solvent should be 20% by weight or more based on the total weight of the carbonizable resin and the disappearing resin from the viewpoint of improving the compatibility between the carbonizable resin and the disappearing resin and reducing the viscosity to improve the fluidity. preferable. On the other hand, from the viewpoint of costs associated with recovery and reuse of the solvent, it is preferably 90% by weight or less based on the total weight of the carbonizable resin and the disappearing resin.

[Step 2]
Step 2 is a step of phase-separating the resin mixture dissolved in Step 1 to form a fine structure and immobilize it. Typically, in this step, the phase separation structure is fixed and the resin mixture is formed into an arbitrary shape such as a fiber or a film.

  Phase separation of mixed carbonizable resin and disappearing resin can be induced by various physical and chemical methods, for example, by thermally induced phase separation method that induces phase separation by temperature change, by adding non-solvent Non-solvent induced phase separation to induce phase separation, flow induced phase separation to induce phase separation by physical field, orientation induced phase separation, electric field induced phase separation, magnetic field induced phase separation, pressure induced phase separation There are various methods such as a reaction-induced phase separation method that induces phase separation using a chemical reaction or a chemical reaction. Among these, methods that do not involve a chemical reaction during phase separation, such as thermally induced phase separation and non-solvent induced phase separation, can easily produce porous carbon materials having a co-continuous porous structure. preferable.

  These phase separation methods can be used alone or in combination. Specific methods for use in combination include, for example, a method in which non-solvent induced phase separation is caused through a coagulation bath and then heated to cause heat-induced phase separation, or a temperature in the coagulation bath is controlled to control a non-solvent induced phase. Examples thereof include a method of causing separation and thermally induced phase separation at the same time, a method of bringing the material discharged from the die into cooling and causing thermally induced phase separation, and then contacting with a non-solvent.

  “No chemical reaction during the phase separation” means that the mixed carbonizable resin or disappearing resin does not change its primary structure before and after mixing. The primary structure refers to a chemical structure that constitutes a carbonizable resin or a disappearing resin. By not involving a chemical reaction such as polymerization during phase separation, it is possible to suppress a change in characteristics such as a significant improvement in elastic modulus and easily form an arbitrary structure such as a fiber or a film.

[Removal of disappearing resin]
It is preferable that the resin mixture in which the microstructure after phase separation is fixed in Step 2 is subjected to the removal treatment of the lost resin before being subjected to the carbonization step (Step 3), simultaneously with the carbonization step, or both. The method for the removal treatment is not particularly limited as long as the disappearing resin can be removed. Specifically, the method of removing the lost resin by chemically decomposing and reducing the molecular weight using acid, alkali or enzyme, the method of removing by dissolving with a solvent that dissolves the lost resin, electron beam, gamma ray, ultraviolet ray, infrared ray A method of decomposing and removing the disappearing resin using radiation such as heat or the like is preferable.

  In particular, when the disappearance resin can be removed by thermal decomposition, a heat treatment can be performed at a temperature at which 80% by weight or more of the disappearance resin disappears in advance, and a carbonization step (step 3) or infusibilization described later. In the treatment, the lost resin can be removed by pyrolysis and gasification. From the viewpoint of increasing the productivity by reducing the number of steps, it is more preferable to select a method in which the lost resin is thermally decomposed and gasified and removed simultaneously with the heat treatment in the carbonization step (step 3) or infusibilization treatment described later. It is.

[Infusibilization]
The precursor material, which is a resin mixture in which the microstructure after phase separation is fixed in step 2, is preferably subjected to an infusibilization treatment before being subjected to the carbonization step (step 3). The infusible treatment method is not particularly limited, and a known method can be used. Specific methods include a method of causing oxidative crosslinking by heating in the presence of oxygen, a method of forming a crosslinked structure by irradiating high energy rays such as electron beams and gamma rays, and impregnating a substance having a reactive group, Examples thereof include a method of forming a crosslinked structure by mixing, and among them, a method of causing oxidative crosslinking by heating in the presence of oxygen is preferable because the process is simple and the production cost can be reduced. These methods may be used singly or in combination, and each may be used simultaneously or separately.

  The heating temperature in the method of causing oxidative crosslinking by heating in the presence of oxygen is preferably 150 ° C. or higher from the viewpoint of efficiently proceeding with the crosslinking reaction, and it can be recovered from weight loss due to thermal decomposition, combustion, etc. of carbonizable resin. From the viewpoint of preventing rate deterioration, the temperature is preferably 350 ° C. or lower.

  Further, the oxygen concentration during the treatment is not particularly limited, but it is preferable to supply a gas having an oxygen concentration of 18% or more, in particular, air as it is because manufacturing costs can be kept low. The method for supplying the gas is not particularly limited, and examples thereof include a method for supplying air directly into the heating device and a method for supplying pure oxygen into the heating device using a cylinder or the like.

  As a method of forming a crosslinked structure by irradiating a high energy beam such as an electron beam or a gamma ray, the carbonizable resin is irradiated with an electron beam or a gamma ray using a commercially available electron beam generator or gamma ray generator. And a method of inducing cross-linking. The lower limit of the irradiation intensity is preferably 1 kGy or more from the efficient introduction of a crosslinked structure by irradiation, and is preferably 1000 kGy or less from the viewpoint of preventing the material strength from being lowered due to the decrease in molecular weight due to cleavage of the main chain.

  A method of forming a crosslinked structure by impregnating and mixing a substance having a reactive group is a method in which a low molecular weight compound having a reactive group is impregnated in a resin mixture, and a crosslinking reaction is advanced by irradiation with heat or high energy rays. And a method in which a low molecular weight compound having a reactive group is mixed in advance and the crosslinking reaction is promoted by heating or irradiation with high energy rays.

  In addition, it is also preferable to remove the lost resin at the same time during the infusibilization treatment because a cost reduction due to a reduction in the number of steps can be expected.

[Step 3]
In step 3, the resin mixture in which the microstructure after phase separation is fixed in step 2 or, if the disappearing resin has already been removed, the remaining portion made of carbonizable resin is fired and carbonized to form the carbide. It is a process to obtain.

  Firing is preferably performed by heating to 600 ° C. or higher in an inert gas atmosphere. Here, the inert gas refers to one that is chemically inert during heating, and specific examples include helium, neon, nitrogen, argon, krypton, xenon, carbon dioxide, and the like. Of these, nitrogen and argon are preferably used from the economical viewpoint. When the carbonization temperature is 1500 ° C. or higher, argon is preferably used from the viewpoint of suppressing nitride formation.

  The flow rate of the inert gas may be an amount that can sufficiently reduce the oxygen concentration in the heating device, and an optimal value can be selected appropriately depending on the size of the heating device, the amount of raw material supplied, the heating temperature, and the like. preferable. The upper limit of the flow rate is not particularly limited, but is preferably set appropriately in accordance with the temperature distribution and the design of the heating device, from the viewpoint of economy and the temperature change in the heating device being reduced. Further, if the gas generated during carbonization can be sufficiently discharged out of the system, a porous carbon material excellent in quality can be obtained, which is a more preferable embodiment. From this, the generated gas concentration in the system is 3000 ppm or less. It is preferable to determine the flow rate of the inert gas so that

  Although the upper limit of the temperature to heat is not limited, if it is 3000 degrees C or less, since a special process is not required for an installation, it is preferable from an economical viewpoint. Moreover, in order to raise a BET specific surface area, it is preferable that it is 1500 degrees C or less, and it is more preferable that it is 1000 degrees C or less.

  About the heating method in the case of continuously performing carbonization treatment, it is a method to take out the material while continuously supplying the material using a roller, a conveyor, or the like in a heating device maintained at a constant temperature. It is preferable because it can be increased.

  On the other hand, the lower limit of the rate of temperature rise and the rate of temperature drop when performing batch processing in the heating device is not particularly limited, but productivity can be increased by shortening the time required for temperature rise and temperature drop, and 1 ° C. It is preferable that the speed is at least 1 minute. Moreover, although the upper limit of the temperature increase rate and the temperature decrease rate is not particularly limited, it is preferable to make it slower than the thermal shock resistance of the material constituting the heating device.

[Activation treatment]
The carbide obtained in step 3 or the carbide obtained by further pulverizing treatment described later can further form pores on the surface by further activation treatment. The activation method is not particularly limited, such as a gas activation method or a chemical activation method. The gas activation method is a method of forming pores by heating at 400 to 1500 ° C., preferably 500 to 900 ° C. for several minutes to several hours, using oxygen, water vapor, carbon dioxide gas, air or the like as an activator. It is. Also, the chemical activation method is one or two kinds of activator such as zinc chloride, iron chloride, calcium phosphate, calcium hydroxide, potassium hydroxide, magnesium carbonate, sodium carbonate, potassium carbonate, sulfuric acid, sodium sulfate, potassium sulfate, etc. This is a method of heat treatment for several minutes to several hours using the above, and after washing with water or hydrochloric acid as necessary, the pH is adjusted and dried.

  Generally, the BET specific surface area increases and the pore diameter tends to increase by further promoting the activation or increasing the mixing amount of the activator. The mixing amount of the activator is preferably 0.5 parts by weight or more, more preferably 1.0 parts by weight or more, and further preferably 4 parts by weight or more with respect to the target carbon raw material. Although an upper limit is not specifically limited, 10 weight part or less is common.

  In the present invention, the chemical activation method is preferably employed because the pore diameter can be increased or the BET specific surface area can be increased. Among them, a method of activating with an alkaline agent such as calcium hydroxide, potassium hydroxide, potassium carbonate is preferably employed.

  When activated with an alkaline agent, the amount of acidic functional groups tends to increase, which may be undesirable depending on the application. At this time, it is also preferable to reduce by performing a heat treatment in a nitrogen atmosphere.

[Crushing treatment]
The particulate porous carbon material can be typically produced by pulverizing the molded body formed in step 2 into a particulate form at any subsequent stage. . The pulverization treatment is preferably performed on the carbide carbonized through the step 3 or the porous carbon material further subjected to the activation treatment because the pulverization is easy.

  Examples of the pulverization treatment include pulverization using a ball mill, a bead mill, a jet mill or the like. Grinding members used for ball mills and bead mills are appropriately selected. Members made of metal oxides such as alumina, zirconia and titania, members coated with nylon, polyolefin, fluorinated polyolefin, etc. with stainless steel, iron, etc. as the core, or stainless steel , Members made only of metals such as nickel and iron.

  In addition, it is also a preferable aspect to use a grinding aid in terms of increasing grinding efficiency during grinding. The grinding aid is arbitrarily selected from water, alcohol or glycol, ketone and the like. As the alcohol, ethanol and methanol are preferable from the viewpoint of availability and cost, and in the case of glycol, ethylene glycol, diethylene glycol, propylene glycol and the like are preferable. In the case of a ketone, acetone, ethyl methyl ketone, diethyl ketone and the like are preferable.

<Method for producing lead-acid battery electrode>
When the porous carbon material of the present invention is used as a sheet, the porous carbon material formed into a fiber is made into a woven fabric, a knitted fabric or a braid using a known loom, knitting machine, etc. It can be made into a non-woven fabric. Moreover, the porous carbon material previously shape | molded in the film form can also be used as it is. A sheet-like porous carbon material thus obtained is mixed with a liquid such as water or an organic solvent and lead or a lead compound and other additives as necessary and mixed. A layer in which the sheet-like porous carbon material is composed of lead or a lead compound by applying to the porous carbon material or by separately preparing a plate-like molded body from a paste and bonding it to the sheet-like porous carbon material Can be produced. Further, by repeating application or bonding as necessary, an electrode in which a sheet-like porous carbon material and a layer made of lead or a lead compound are laminated a plurality of times can be produced.

  When a particulate porous carbon material is used, it is preferable to prepare an electrode by preparing an electrode paste containing the porous carbon material and lead or a lead compound, and applying the paste to a current collector. The electrode paste can be roughly prepared by two methods, a dry method and a wet method.

  When preparing an electrode paste by a dry method, a method of mixing a porous carbon material and lead or a lead compound can be mentioned. The electrode paste may contain other materials such as a binder and a conductive aid as necessary. The method of mixing is not particularly limited, but a method of kneading with a twin screw extruder, a Henschel mixer, a roller mill, or the like is preferable from the viewpoint of easy heating and production efficiency. Although it is possible to include a solvent in the dry method, the solvent in this case does not dissolve the binder, and 30% of the total amount of the coating liquid from the viewpoint of improving the effect when mixing the electrode paste by shearing. It is preferable to add less than wt%.

  After mixing, while removing the solvent in the heated state, or after forming and heating, the solvent is removed, and the particulate porous carbon material is a matrix made of lead or a lead compound by forming into a flat plate shape. An electrode dispersed therein can be produced.

  Examples of the method for producing the electrode paste by a wet method include a method of preparing a slurry-like electrode paste by mixing a porous carbon material, a solvent, and lead or a lead compound. The electrode paste may contain other materials such as a binder and a conductive aid as necessary. The mixing procedure is not limited, but a method in which all materials are charged at the same time, a method in which only solids are mixed in advance, or only a component that is soluble in the solvent is mixed with the solvent in advance. A method of preparing the can be considered. The mixing method is not particularly limited, but from the viewpoint of mixing efficiency, a closed rotary stirrer is preferably used.

  By applying the electrode paste thus prepared to the current collector, an electrode dispersed in a matrix made of lead or a lead compound can be produced. The method for applying the electrode paste is not particularly limited, and examples thereof include a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, and brush coating.

  As the current collector, a conventionally known one can be used, and a foil shape, a lattice shape, a mesh shape, or a fabric shape can be arbitrarily selected.

<Method for producing lead-acid battery>
The cell assembly method of the lead storage battery of the present invention is not particularly limited, and is performed by a generally used method. Preferably, a lead storage battery electrode made of a porous carbon material and an electrolytic solution are placed in a cell container. It is manufactured by hermetically sealing. The lead-acid battery electrode is appropriately punched out, sized according to the shape of the cell by a method such as cutting, put into a container by winding, stacking or folding as necessary, and then injecting the electrolyte into the container and sealing it Can be manufactured. In addition, a lead storage battery impregnated with an electrolyte may be stored in a container. In addition, it is also a preferable aspect to use a separator, a spacer, or a gasket as necessary when assembling the cell.

Claims (13)

An electrode for a lead storage battery in which a porous carbon material having a co-continuous porous structure portion in which a carbon portion and a void each form a continuous structure is combined with lead or a lead compound. The lead-acid battery electrode according to claim 1, wherein the co-continuous porous structure portion of the porous carbon material has a periodic structure. The lead-acid battery electrode according to claim 2, wherein a structure period of the co-continuous porous structure portion is 0.002 μm to 20 μm. The lead-acid battery electrode according to any one of claims 1 to 3, wherein the porous carbon material has pores having an average diameter of 0.01 to 10 nm on a surface. The lead-acid battery electrode according to claim 4, wherein the pore volume calculated by the MP method is 0.1 ml / g or more. The electrode for a lead storage battery according to any one of claims 1 to 5, wherein the porous carbon material has a dense portion substantially having no co-continuous porous structure. The lead-acid battery electrode according to any one of claims 1 to 6, wherein a part of the lead or lead compound penetrates into the void of the co-continuous porous structure of the porous carbon material. The lead-acid battery electrode according to any one of claims 1 to 7, wherein the particulate porous carbon material is dispersed in a matrix made of lead or a lead compound. The electrode for lead acid batteries in any one of Claims 1-7 in which the layer containing a particulate porous carbon material is formed in the surface of the molded object which consists of lead or a lead compound. The lead-acid battery electrode according to any one of claims 1 to 7, wherein the film-like porous carbon material is laminated with a layer made of lead or a lead compound. The lead-acid battery electrode according to any one of claims 1 to 7, wherein a woven fabric or a non-woven fabric formed from a fibrous porous carbon material is laminated with a layer made of lead or a lead compound. The electrode for a lead storage battery according to any one of claims 1 to 7, wherein a non-woven fabric formed from a fibrous porous carbon material is filled with a matrix made of lead or a lead compound. The lead acid battery which uses the electrode for lead acid batteries in any one of Claims 1-12.