JP6119311B2 - Control valve type lead acid battery - Google Patents

Description

  The present invention relates to a control valve type lead storage battery excellent in charge acceptability.

  Lead-acid batteries are inexpensive and highly reliable. Therefore, they are widely used as power sources for starting automobiles, power sources for electric vehicles such as golf carts, and power supplies for industrial equipment such as uninterruptible power supplies. It is used.

  In recent years, various measures for improving fuel efficiency have been studied for automobiles in order to prevent air pollution and global warming. Automobiles that have taken measures to improve fuel efficiency include power generation control vehicles that use the engine rotation efficiently to power the vehicle, and stop running by suppressing alternator power generation to reduce the load on the engine as much as possible. It is expected that an idling stop system vehicle (hereinafter referred to as an ISS vehicle) that reduces the operating time of the engine by stopping the engine sometimes to prevent unnecessary idling operation from spreading. ISS vehicles are also collectively referred to as micro-hybrid system vehicles.

In an ISS vehicle, the engine is stopped during stoppage and stoppage, and the engine is started when the vehicle is started. Therefore, the number of engine starts increases, and a large current discharge of the lead storage battery is repeated each time.
In addition, since the alternator does not generate power when idling is stopped, power is supplied to the in-vehicle device only from the lead storage battery. For this reason, the capacity | capacitance of a lead storage battery is used in the state charged partially, ie, the state of PSOC (Partial State Of Charge), ensuring the capacity | capacitance required for the next engine start etc.
For this reason, the usage method of the lead acid battery mounted in an ISS vehicle differs fundamentally from the conventional lead acid battery. Conventional lead-acid batteries carry a large current only at the time of start-up, and thereafter have been used in a fully charged state by charging an alternator.

  A lead storage battery required for an ISS vehicle needs to have the following characteristics. 1) The battery should have high-speed charging performance that can immediately charge the power consumed by the lead-acid battery and maintain a predetermined PSOC state, and high-speed charging performance necessary to store the brake regenerative energy in the battery. This has a charging rate that can sufficiently accept the output current from the alternator. 2) A highly durable lead-acid battery having a sufficient service life with PSOC.

  In 1) above, the alternator output current of the ISS vehicle has a performance sufficiently exceeding 1.5 times the charge acceptance performance of the conventional lead-acid battery. For example, a conventional 80D23 type lead acid battery defined by Japanese Industrial Standard (JIS) has a capacity of 52 Ah. When an 80D23 type lead-acid battery is charged at a constant voltage of 14V, the charging current draws a curve that decays with time. This behavior is a phenomenon that can be explained from the characteristics of the reaction overvoltage of the electrochemical reaction. At this time, the initial charging currents at the first and fifth charging times are about 40 amperes (A) and about 30 A at 25 ° C., respectively. On the other hand, the alternator output current of an ISS vehicle equipped with an 80D23 type lead storage battery exceeds 60A. For this reason, in the conventional 80D23 type lead acid battery, after the capacity | capacitance of a battery falls, there is no charging performance corresponding to the output current of an alternator. If the reduced battery capacity cannot be recovered, engine restart will be hindered, increasing the number of situations where idling can not be stopped. For this reason, improvement in fuel consumption cannot be expected. If the reduced capacity of the lead storage battery cannot be recovered quickly by the alternator, the discharge and charge cycles in the ISS of the lead storage battery mounted on the ISS car must be stopped due to insufficient charging. As described above, the ISS vehicle requires a lead storage battery having high-speed charging performance for rapidly recovering at least the power of the used lead storage battery. Therefore, it is ideal that the charge acceptance performance of the lead storage battery mounted on the ISS vehicle has a characteristic that the output current of the alternator can be sufficiently received by the battery. In this respect, in the case of an 80D23 type lead-acid battery mounted on an ISS vehicle, charging acceptance performance of a level exceeding 60 A is required at 25 ° C. and 14 V constant voltage charging in the first second. This value corresponds to an improvement in charging performance at least 1.5 times that of a conventional lead acid battery.

  In the above 2), when the lead-acid battery is used under PSOC, its life tends to be shorter than when it is used in a fully charged state. The reason for the shortening of the life when used under PSOC is that if charging / discharging is repeated in a state where charging is insufficient, lead sulfate produced on the negative electrode plate becomes coarse during discharge, and lead sulfate is generated by charging. It is thought that it becomes difficult to return to the metallic lead that is a thing. Therefore, in lead storage batteries used under PSOC, in order to extend their life, charge acceptance is improved (allowing as many charges as possible in a short time), and charging is excessively insufficient. It is necessary to prevent the charge / discharge from being repeated in a state where the lead is charged and to suppress the lead sulfate from becoming coarse due to the repeated charge / discharge.

  As described above, the most important problem of the lead storage battery mounted in the ISS vehicle, that is, the micro hybrid system vehicle is the charge acceptance performance. In order to sufficiently operate the idling stop system of an ISS vehicle and achieve an improvement in fuel consumption, a lead storage battery having excellent charge acceptance performance is required. It is considered that the charge acceptance performance of a lead-acid battery for an ISS vehicle is required to be 1.5 times or more that of a conventional lead-acid battery.

  Lead-acid batteries for ISS vehicles are divided into liquid-type lead-acid batteries and control-valve-type lead-acid batteries (hereinafter referred to as “VRLA”), each having advantages and disadvantages. Liquid lead-acid batteries are strong even in high-temperature environments due to their abundance of electrolyte (dilute sulfuric acid). On the other hand, VRLA is hermetically sealed, has difficulty in escaping heat, and has a limited amount of electrolyte, which is inferior in heat resistance compared to liquid lead-acid batteries. VRLA uses a retainer containing an electrolytic solution (dilute sulfuric acid) in a large amount as a separator, and is therefore more expensive than a liquid type. A VRLA using a retainer, so-called AGM (Absorptive Glass Mat), generally has a structure in which oxygen gas generated at the positive electrode due to electrolysis of water in the electrolyte is absorbed on the negative electrode plate. It is said to be sealed and maintenance-free lead-acid battery. When viewed as a lead-acid battery for ISS cars, the biggest feature of VRLA is that it has excellent cycle durability. Originally, VRLA has a structure in which an electrolytic solution is included in a retainer so that the electrolytic solution does not overflow, and is in contact with the positive electrode plate and the negative electrode plate in a state where the retainer is pressurized. In ISS cars, rapid recharge performance is required for lead-acid batteries to regenerate energy during braking. Since VRLA has the separator structure as described above, sulfate ions that suddenly spring out from the electrode plate due to rapid regenerative charging during braking of an ISS vehicle are held by an adjacent retainer. For this reason, the so-called sulfuric acid stratification phenomenon in which the sulfuric acid concentration distribution is seen in the vertical direction of the container like the liquid lead-acid battery is less likely to occur. Since VRLA is difficult to stratify, it has excellent cycle durability. In the case of a liquid lead-acid battery, there is an electrolyte solution space between the electrode plate and the separator, and since the separator is made of thin polyethylene, there is no function and thickness for storing sulfate ions like a retainer. For this reason, the sulfate ions that have springed up during charging tend to settle in the electrolyte as they are. When sulfate ions settle, the electrolyte specific gravity at the bottom of the battery case increases and the specific gravity at the top decreases. When such stratification occurs, the rate of the discharge reaction changes with the concentration distribution of sulfate ions, and the reaction efficiency varies depending on the location of the electrode plate. As a result, the battery reaction is concentrated at the place where the reaction is likely to occur, the current density of the reaction portion is increased, and as a result, the deterioration is accelerated at the portion where the reaction is likely to occur, and the life is quickly reached.

  Although VRLA is a maintenance-free structure and a structure that is strong against stratification, the absolute amount of electrolyte is smaller than that of a liquid lead-acid battery. The battery capacity of VRLA is determined by the amount of sulfuric acid in the electrolyte contained in the retainer. For this reason, in order to ensure a predetermined battery capacity, it is necessary to set the sulfuric acid concentration of the electrolytic solution of VRLA higher than that of the liquid lead acid battery.

However, the charge reaction rate of the lead-acid battery decreases as the sulfuric acid concentration increases, as shown below. This is because the rate of charge reaction of the lead storage battery is greatly affected by the concentration of lead divalent ions (Pb ²⁺ ) generated by dissolution or dissociation of lead sulfate. That is, since the concentration of lead divalent ions (Pb ²⁺ ) decreases as the sulfuric acid concentration in the electrolytic solution increases (Hands “Lead-Acid Batteries” p. 27, (1977), John Wiley & Sons, Inc.). ), The charging reaction rate is reduced.

  In lead-acid batteries, the charge acceptability of the positive electrode active material is originally high, but it has been said that the charge acceptability of the negative electrode active material is poor. For this reason, in order to improve the charge acceptance of a lead storage battery, it was generally essential to improve the charge acceptance of a negative electrode active material. Therefore, conventionally, efforts have been made to improve the charge acceptability of the negative electrode active material. Patent Documents 1 and 2 propose VRLA that increases charge acceptance by increasing the amount of carbonaceous conductive material added to the negative electrode active material and improves the life under PSOC.

  Even in a liquid lead acid battery, it is conceivable to increase the amount of carbonaceous conductive material added to the negative electrode active material, but if the amount of carbonaceous conductive material added to the negative electrode active material in the liquid lead acid battery is increased unnecessarily, The carbonaceous conductive material in the negative electrode active material flows into the electrolytic solution and causes turbidity in the electrolytic solution. In the worst case, an internal short circuit is caused. Therefore, in a liquid lead-acid battery, the amount of carbonaceous conductive material added to the negative electrode active material must be limited, and the charge acceptability of the lead acid battery as a whole by adding the carbonaceous conductive material to the negative electrode active material. There are limits to improving

  On the other hand, in lead acid batteries, lignin has been added to the negative electrode active material for a long time. Lignin exhibits excellent surface-active effect with a small amount of addition. As a result, the electrolytic solution penetrates into the pores of the active material, and the effective reaction area of the battery reaction increases. It is said that the added lignin also has an effect of suppressing the coarsening of battery reaction products such as lead sulfate. Thereby, the discharge reaction is increased by the addition of lignin. On the other hand, lignin has a side-effect that inhibits the charging reaction. The cause of inhibiting the charging reaction is thought to be that lignin is adsorbed on lead ions, which are the starting materials for the charging reaction, to reduce the reactivity of the lead ions. Here, lead ions, which are starting materials for the charging reaction, are supplied by the dissociation equilibria of lead sulfate. Therefore, lignin addition to the negative electrode active material is an important additive for improving the discharge reaction. However, at the same time, the addition of lignin to the negative electrode active material hinders the charging reaction, thus hindering improvement in acceptability.

  From this point of view, instead of lignin, sodium lignin sulfonate with a sulfo group introduced into the α-position of the side chain of the phenylpropane structure, which is the basic structure of lignin, bisphenols, aminobenzene sulfonic acid, formaldehyde condensates, etc. It has been proposed to add to the negative electrode active material.

  For example, Patent Document 3 and Patent Document 4 disclose adding a bisphenol, aminobenzenesulfonic acid, formaldehyde condensate, and a carbonaceous conductive material to the negative electrode active material. In particular, Patent Document 4 shows the effect of suppressing the coarsening of lead sulfate by selecting bisphenols, aminobenzenesulfonic acid, and formaldehyde condensates as organic compounds that suppress the coarsening of lead sulfate associated with charge and discharge. Sustaining and adding a carbonaceous conductive material to improve charge acceptance are disclosed. Patent Document 5 discloses that conductive carbon and activated carbon are added to the negative electrode active material to improve discharge characteristics under PSOC.

  Further, Patent Document 6 (Japanese Patent Laid-Open No. 10-40907) discloses that the specific surface area of the positive electrode active material is increased to increase the discharge capacity. In this method, lignin is added to the electrolytic solution at the time of battery formation to refine the positive electrode active material and increase the specific surface area. Patent Document 6 discloses an invention for focusing on the positive electrode and increasing the discharge capacity of the battery. The charge acceptability and cycle characteristics under PSOC required when viewed as a lead storage battery of an ISS car are disclosed. In the improvement, the expected effect cannot be obtained.

  The prior art does not show any inherent conditions based on the principle of battery reaction in achieving higher charge acceptance performance. For this reason, battery characteristics have been improved by individual constituent factors such as negative electrode characteristics and positive electrode characteristics.

  However, in order to improve the battery, it is important to clarify the basic requirements based on the principle of battery reaction in order to obtain a battery that is 1.5 times more than conventional lead-acid batteries.

  That is, when the battery is improved with individual constituent factors, it may be difficult to achieve the target characteristics with one constituent factor. In such a case, essential requirements based on the principle of the battery reaction are arranged, and in order to satisfy the requirements, it is necessary to examine a plurality of other constituent factors. In other words, the improvement of one component factor does not satisfy the necessary condition and the target characteristic may not be achieved, but the examination of another battery component factor increases the possibility that the necessary condition is satisfied and the target characteristic can be achieved. . In other words, in order to achieve the target characteristics for improving the charge acceptance performance, the examination of essential requirements based on the principle of battery reaction can make it possible to derive the most efficient and effective basic battery configuration. it is conceivable that.

  The conventional literature clearly shows the essential requirements based on the principle of the battery reaction and the battery configuration conditions based on the indicated requirements for higher charge acceptance performance, which is an important proposition of lead-acid batteries of ISS cars. It has not been. Therefore, neither the content of a structure for obtaining the battery more than 1.5 times of the conventional lead acid battery nor a basic requirement is disclosed.

JP 2003-36882 A Japanese Patent Laid-Open No. 07-201331 JP-A-11-250913 JP 2006-196191 A JP 2003-051306 A Japanese Patent Laid-Open No. 10-40907

  As mentioned above, improving the charge acceptability of the negative electrode active material as in the prior art and improving the life performance will improve the charge acceptability of the lead storage battery and the life performance when used under PSOC. There is a limit, and it is difficult to further improve the performance of lead-acid batteries used under PSOC. In addition, the above-mentioned patent document does not disclose basic requirements based on the principle of a battery and a battery configuration necessary for obtaining a battery having a charge acceptance performance 1.5 times or more that of a conventional lead storage battery. .

  The first of the objects of the present invention is to clarify the necessary conditions based on the principle of the battery reaction that the charge acceptance performance of 1.5 times or more of the conventional lead-acid battery is configured. The second purpose is to determine the required battery configuration based on the identified requirements. The lead acid battery which is the object of the present invention is to provide a VRLA having cycle durability more than a liquid lead acid battery in an ISS vehicle application.

In order to solve the above problems, the VRLA features of the present invention are as follows.
A battery case in which a negative electrode plate formed by filling a negative electrode current collector with a negative electrode active material and a positive electrode plate formed by filling a positive electrode active material with a positive electrode current collector through a retainer together with an electrolytic solution A VRLA having a configuration housed therein, in which charging is performed intermittently and high rate discharge to a load is performed in a partially charged state, at a temperature of 25 ° C., a specific gravity of 1.32 (20 ° C. conversion, in electrolytic solution hereinafter the same), potential reference between the negative electrode veneer constituting the negative electrode plate (area 108cm ^2), the positive pole, single plate constituting the positive against the positive electrode plate to the negative electrode veneer and (area 108cm ²⁾ A VRLA having an electrochemical measurement system in which a reference electrode is installed is prepared. The VRLA is charged with a charging voltage of 2.33 V, and the relationship between the negative charging overvoltage and the positive charging overvoltage applied at the time of 5 seconds from the start of charging and the corresponding charging current is plotted, and a current potential curve is created. . In the current-potential curve, in the region obtained by plotting the point at which the absolute value of the charge overvoltage starts to increase from 0 (zero) as an origin, and approximating a straight line from the origin, | [negative electrode charge overvoltage (MV) / current (ampere)] | ≦ 10.4 A negative electrode plate comprising a negative electrode active material and a positive electrode satisfying [positive electrode charge overvoltage (mV) / current (ampere)] ≦ 19.6 It is characterized by comprising a positive electrode plate comprising an active material.

  The present invention electrolyzes an electrode plate group in which a negative electrode plate formed by filling a negative electrode current collector with a negative electrode active material and a positive electrode plate formed by filling a positive electrode active material with a positive electrode current collector via a retainer. It is intended for a VRLA that has a configuration housed in a battery case together with a liquid, is charged intermittently, and discharges at a high rate to a load in a partially charged state.

First, the necessary conditions based on the electrochemical basic principle of the battery reaction will be described.
In the present invention, the necessary condition based on the electrochemical basic principle of the battery reaction is indicated by “overpotential” of the electrochemical reaction of each of the negative electrode and the positive electrode corresponding to a predetermined charging voltage. That is, the necessary conditions for obtaining the performance exceeding 1.5 times the charge acceptance performance of the conventional battery are shown by the conditions relating to the overvoltage of the battery reaction. If the necessary conditions defined by the overvoltages of the negative electrode and the positive electrode shown in the present invention are satisfied at a predetermined charging voltage, a performance exceeding 1.5 times the charge acceptance performance of a conventional battery can be obtained. The structural conditions of the reaction active material of the negative electrode and the positive electrode satisfying the overvoltage condition indicated as the necessary conditions will be clarified, and an example of the structure of the battery satisfying the necessary conditions will be shown by examples.

  It is necessary to clarify the characteristic conditions required for lead-acid batteries in the ISS car market, the basic parameters of the battery, the relationship between overvoltage and charge acceptance performance, and to achieve more than 1.5 times the charge acceptance performance of conventional lead-acid batteries Conditions were shown, and the battery configuration and active material conditions for satisfying the conditions were clarified. As a result, the characteristics required for VRLA in the ISS car market have been greatly improved, and it has been possible to obtain guidelines for further improving battery characteristics. Thereby, the vehicle exhaust gas countermeasure by the ISS technology is efficiently executed and contributes to the suppression of global warming.

A current-potential curve showing the relationship between the charging current and the potential of the negative electrode plate and the positive electrode plate when charging a vehicle VRLA with an open circuit voltage of about 12 V with a charging voltage of 14 V (constant). It is a schematic diagram. It is a curve figure which shows the relationship between sulfuric acid specific gravity and Pb2 ⁺ ion concentration. Current potential representing the relationship between the charging current and the potential of the negative electrode plate and the positive electrode plate when charging is performed using a single plate of VRLA for automobiles with an open circuit voltage of about 2 V with a charging voltage of 2.333 V (constant). It is a figure which shows a curve. It is a figure which shows the electrical power collector (grid body) of the electrode plate used for the JIS B type lead acid battery used for electrochemical measurement. It is a figure which shows the time change curve of a charging current. It is a figure which shows the result of having extracted the formaldehyde condensate of the bisphenol A aminobenzenesulfonic acid sodium salt added to the negative electrode from the negative electrode plate after conversion, and measuring the spectrum by NMR spectroscopy.

  The relationship between charge acceptance performance and overvoltage is clarified based on electrochemical reaction kinetics. This shows that overvoltage is a basic parameter in the kinetics of battery reaction, and clarifies the significance of focusing on overvoltage as a necessary condition based on the principle of battery reaction.

  The battery reaction is explained by an electrochemical reaction between the negative electrode and the positive electrode. The charge and discharge reactions of the negative electrode and the positive electrode each have a unique simple electrochemical reaction system. A unique simple electrochemical reaction system means that it is not a mixture of a plurality of electrochemical reactions, but only one kind of electrochemical reaction (Yota Tamamushi, “Electrochemistry (2nd edition)” p. 199, (1991), Tokyo Chemical Doujin or Allen J. Bard and Larry R. Faulkner, “ELECTROCHEMICAL METHODS” p. 7, (2001), John Wiley & Sons, Inc.). The negative electrode and positive electrode reactions of the battery reaction are each composed of one independent electrochemical reaction. The charge acceptance performance is a performance related to the charge reaction. The reaction rate of the charging reaction is related to the electric potential of the simple electrochemical reaction system of the negative electrode and the positive electrode in the electrochemical of electrochemical kinetics (Yota Tamamushi, “Electrochemistry (2nd edition)” pp. 1 235-236, (1991), Tokyo Kagaku Dojin, or Allen J. Bard and Larry R. Faulkner, “ELECTROCHEMICAL METHODS”, p. 99-107, (2001), John Wiley & Sons Inc.). In electrochemical reactions, the reaction rate is the current itself. That is, the charge reaction rate and the discharge reaction rate are equivalent to the charge current and the discharge current, respectively. When the potential of the simple electrochemical reaction system of the negative electrode and the positive electrode is the equilibrium potential of each reaction system, the sum of the absolute values of the respective equilibrium potentials corresponds to the open circuit voltage of the battery. The equilibrium potential is internationally displayed on the basis of a standard hydrogen electrode and is usually abbreviated as SHE. In a lead-acid battery, when the simple electrochemical reaction system of the negative electrode and the positive electrode is in a standard state defined by electrochemical, the potential of the negative electrode is -0.36 V vs. SHE, and the potential of the positive electrode is +1.69 V vs.. SHE. Therefore, if the lead acid battery is in a standard state defined by electrochemistry (25 ° C., ion activity 1, etc.), the open circuit voltage is 2.05V.

  When the negative and positive electrode potentials deviate from the equilibrium potential, the potential deviating from the equilibrium potential is defined as “overvoltage”. That is, the overvoltage is the difference between a certain potential of the negative electrode and the positive electrode and the equilibrium potential. The relationship between the reaction rate and the overvoltage of the simple electrochemical reaction system is related by the electrochemical reaction rate equation (Yota Tamamushi, “Electrochemistry (2nd edition)” p.236, (1991), Tokyo Chemical Dojin, or Allen J. Bard and Larry R. Faulkner, “ELECTROCHEMICAL METHODS” p. 99, (2001), John Wiley & Sons Inc.). In the present invention, the overvoltage is expressed by the usual Greek letter “η”. Unlike the relational expression between the overvoltage and the reaction rate in the general simple electrochemical reaction rate equation, the electrochemical reaction rate equation of a general battery including a lead storage battery is complicated. This is because an electrochemical reaction system is generally decomposed into several elementary reactions in which chemical reactions and several electron transfer reaction steps are mixed, and depending on which elementary reaction step the rate-determining step that determines the reaction rate is located. This is because the chemical reaction rate equation is affected. However, in any electrochemical reaction rate equation, the overvoltage is a decisive parameter that affects the reaction rate. The electrochemical reaction rate equation includes other parameters such as the concentration of the reactant, the reaction area, the rate constant or exchange current density, the diffusion coefficient of the reactant, and the gas constant. (Gas constant, Faraday constant, transient coefficient, absolute temperature, etc.) In the electrochemical reaction rate equation, the overvoltage term is based on the constant e. The change in overvoltage has a decisive influence on the electrochemical reaction rate.

  When the charging reaction proceeds, the potential of the simple electrochemical reaction system of the positive electrode shifts in the positive potential direction more than the equilibrium potential of the positive electrode. Conversely, the potential of the simple electrochemical reaction system of the negative electrode shifts in the negative potential direction with respect to the equilibrium potential of the negative electrode. Therefore, in the case of a charging reaction, the overvoltage at the positive electrode is a potential in the positive direction with respect to the equilibrium potential, and the overvoltage at the negative electrode is a potential in the negative potential direction with respect to the equilibrium potential. In the case of a charging reaction, the potential difference between the negative electrode and the positive electrode, that is, the voltage is higher than the open circuit voltage by an overvoltage.

  Charging and charging reactions are in principle as described above. In other words, the overvoltage at the negative electrode of the lead storage battery is applied from the alternator or the like as a potential in the negative direction with respect to the equilibrium potential, and the potential at the positive electrode is applied in the positive direction with respect to the positive potential. The charging voltage of the alternator varies depending on the vehicle type. For this reason, in the present invention, the charging voltage is 14V, which is also used as the charging voltage of the cycle pattern of the BATTERY ASSOCIATION OF JAPAN standard SBA S0101, which is used as one of the cycle tests of lead-acid batteries for ISS cars. The following shows how the relationship between charge acceptance performance and overvoltage is expressed mathematically.

Overvoltages applied to the negative electrode and the positive electrode with respect to a voltage of 14 V applied from the alternator are denoted as η (−) and η (+), respectively. The charging currents flowing at the negative electrode and the positive electrode with respect to each overvoltage are denoted as i (−) and i (+), respectively. The charging current flowing through the negative electrode and the positive electrode is expressed by Equations 1 and 2 with η as a function from the reaction rate equation. Here, the detailed content of the formula is not necessary, and it is only necessary to define that the electrochemical reaction rate formulas of the negative electrode and the positive electrode are different.
i (−) = f (η (−))...
i (+) = g (η (+))... Equation 2
Here, f (η (−)) and g (η (+)) each represent a function based on electrochemical reaction kinetics. In the case of the present invention, it is not necessary to obtain a purely accurate theoretical current potential curve. The rate equation in the present invention can be substituted with a charging current and potential curve or a charging current and overvoltage curve observed with a reaction active material actually used. Since the current corresponds to the reaction rate, these current-potential curves are basic data showing the relationship between the actual rate and potential (overvoltage) based on the electrochemical reaction kinetics.

Assuming that the open circuit voltage is 12V, the following relational expression is established between η (−), η (+) and the charging voltage 14V. Overvoltage is displayed in absolute value. In the case of a charging reaction, the negative voltage shifts in the negative potential direction and the positive electrode shifts in the positive potential direction. Therefore, the absolute value display is suitable for understanding the contents of the present invention.
| Η (−) | + | η (+) | + 12 = 14 Equation 3
The absolute values of the charging currents flowing in the negative electrode and the positive electrode shown in Equations 1 and 2 are equal. Therefore, the following relational expression is obtained. If the current has a direction and the charging current at the negative electrode is positive, the charging current at the positive electrode has a negative sign. Therefore, the absolute value display is suitable for understanding the contents of the present invention.
| I (−) | = | i (+) |
Or
| F (η (−)) | = | g (η (+)) |
From Equation 3, the sum of | η (−) | and | η (+) | is 2V. To what extent 2V is distributed to | η (−) | and | η (+) | solve the simultaneous equations of Equation 3 and Equation 5 with η (−) and η (+) as unknowns, respectively. Can be obtained.

Here, the conditions under which a battery having a charge acceptance performance 1.5 times or more that of a conventional lead storage battery is obtained are as follows. If the overvoltage and electrochemical reaction rate equations shown in Equations 1 to 5 correspond to conventional batteries, the overvoltage and electrochemical reaction rate equations must be distinguished. This is because if the composition of the active material or the like changes and the charge reaction rate becomes faster, it must be considered that the rate equation has changed. In general, it is considered that the overvoltage distribution of 2 V in total distributed in the negative electrode and the positive electrode also changes. Regarding a battery having a charge acceptance performance of 1.5 times or more that of a conventional lead-acid battery, the overvoltages applied to the negative electrode and the positive electrode are η _1.5 (−), η _1.5 (+), and the charge flowing through the negative electrode and the positive electrode, respectively. The currents are i _1.5 (−) and i _1.5 (+), respectively, and the electrochemical reaction rate equations regarding the charging reaction of the negative electrode and the positive electrode are h (η _1.5 (−)) and j (η _{1. 5} (+)), the following relational expression is established.
| Η _1.5 (−) | + | η _1.5 (+) | + 12 = 14 Expression 6
| I _1.5 (−) | ≧ 1.5 | i (−) |
| I _1.5 (−) | = | i _1.5 (+) |
| H (η _1.5 (−)) | = | j (η _1.5 (+)) |
From Equation 6, the sum of | η _1.5 (−) | and | η _1.5 (+) | is 2V, the same as the sum of | η (−) | and | η (+) |. Similarly, how 2V is distributed to | η _1.5 (−) | and | η _1.5 (+) | is similar to η _1.5 (−) and η _1.5 (+). It can be obtained by solving simultaneous equations of Equation 6 and Equation 9 as unknowns.

That is, when the charging voltage is set to a certain value, the sum of the overvoltages of the negative electrode and positive electrode charging reactions is constant regardless of the speed of the charging reaction. Even when the charge reaction rate is 1.5 times that of the conventional battery, when the 14V charge voltage is common, the sum of the absolute values of the overvoltages of the negative electrode and the positive electrode is about 2V. This value is obtained when 6 single cells are connected in series (usually a battery for automobiles is 12V), and when viewed per single cell, the total overvoltage is 0.333V / single cell. That is, when the charging current is 1.5 times, 1.5 | f (η (−)) | = | h (η _1.5 (−)) | .... Formula 10
It is. It means that the charge reaction rate equation changes from f (η (−)) to h (η _1.5 (−)) by improving the negative electrode. Here, in order to obtain a charging current of 1.5 times, it is assumed that the active material of the negative electrode is improved, and the positive electrode remains as before. In this case, the overvoltage of the improved negative electrode charging reaction, | η _1.5 (−) |, is necessarily smaller than | η (−) | before improvement. The reason is as follows. From Equation 5, the conventional positive electrode active material requires 1.5 times the reaction rate, 1.5 | g (η (+)) |, and 1.5 times the current if the overvoltage remains η (+). Can not be washed. Therefore, the overvoltage of the charge reaction of the positive electrode, which is a conventional active material, increases according to the speed equation up to the overvoltage necessary for flowing a current of 1.5 times. The constraint conditions regarding the overvoltage of the negative electrode and the positive electrode at this time are Expression 3 and Expression 6.

  For this reason, when the overvoltage of the positive electrode charging reaction increases, the overvoltage of the improved negative electrode charging reaction decreases. Then, the greater the improvement effect of the negative electrode active material, the smaller the negative electrode overvoltage and the higher the positive electrode overvoltage. The overvoltage of the negative electrode necessary for satisfying the target charge acceptance current is obtained in principle using Equations 6 to 10.

  On the other hand, the same applies to the case where the negative electrode active material is kept as it is, the positive electrode active material is improved, and the charge acceptance performance is 1.5 times that of the conventional one. In this case, it is the reverse of the case where the negative electrode is improved. That is, the overvoltage of the improved charge reaction of the positive electrode is reduced, and the overvoltage of the non-improved negative electrode is increased.

  It is clear from the above principle study that when both the negative electrode and the positive electrode are improved, the highest improvement effect is obtained as compared with the case where only the negative electrode and only the positive electrode are improved. In this case, the magnitude change of the charge reaction overvoltage of each of the negative electrode and the positive electrode is complicated. That is, when the negative electrode is improved, the absolute value of the charge reaction overvoltage of the negative electrode is lowered and the positive electrode is raised according to Equations 3 and 6. When the charge receiving performance of the positive electrode is further improved by using the improved negative electrode here, the positive voltage overvoltage of the positive electrode is decreased and the absolute value of the negative voltage of the negative electrode is increased according to Equations 3 and 6.

On the other hand, the relationship between the overvoltage and current around the equilibrium potential is generally given by the following linear relationship of Eq. 11 (Yuta Tamamushi, “Electrochemistry (2nd edition)” p. 243, (1991), Tokyo Chemical Dojin or Allen J. Bard and Larry R. Faulkner, “ELECTROCHEMICAL METHODS” p.106, (2001), John Wiley & Sons Inc.).
| Η | / | i | = (RT / nF) ((1 / I ₀ ) + (1 / | Ia |) + 1 / | Ic |) Equation 11
Where | i | is the absolute value of the current density near the equilibrium potential, R is the gas constant, T is the absolute temperature, n is the number of reaction electrons, F is the Faraday constant, I ₀ is the exchange current density, and | Ia | The absolute value of the limiting current density in the reaction, | Ic |, is the absolute value of the limiting current density in the cathode reaction. The right side of Equation 11 is a constant term unique to each electrochemical system. In the present invention, the gradient of the overvoltage and current is shown using a linear relationship appearing in the low overvoltage region obtained by the relationship between the overvoltage and current, and the condition where the charging current exceeds 1.5 times with the magnitude of the linear gradient. The same applies to the case of looking at the total current, not the current density. Even in the relationship between the current potential curve of the total current and the overvoltage, the linear relationship of Equation 11 does not change. Thus, in a pure theoretical aspect, | η | / | i | has a condition for giving a linear relationship. In the present invention, from the relationship between the initial charging current and the overvoltage of the current-potential curve, an area that can be linearly similarly set is set, and the gradient corresponding to | η | / | i | is obtained. As a result, it is possible to define the charging current related to overvoltage and current by 1.5 times and conditions exceeding 1.5 times. In the linear gradient obtained in this way, the condition shown in Equation 11 is the lower limit. The value of | η | / | i | obtained in this experiment is not smaller than the value shown in Equation 11.
FIG. 1 is a schematic diagram of a current-potential curve. That is, the relationship between the above formulas of overvoltage and charging current is visualized in the figure. In the case where a current-potential curve is obtained, FIG. 1 also includes a principle for obtaining a charging current. FIG. 1 shows the content for a 12V battery, with an open circuit voltage of 12V. In the figure, N11 shows the current potential curve of the negative electrode of the conventional lead storage battery, and P11 shows the current potential curve of the positive electrode of the conventional lead storage battery. Here, it is assumed that electrode plates having the same area are used, and the vertical axis indicates current. N22 shows the current potential curve of the negative electrode with improved charge acceptance performance, and P22 shows the current potential curve of the positive electrode with improved charge acceptance performance. Therefore, N22 has a larger charging current than N11 for the same overvoltage (potential). Similarly, P22 has a larger charging current than P11 for the same overvoltage (potential). When the charging voltage 14V is represented by the potential width shown in FIG. 1, the charging current of the conventional battery is I11. In the figure, four lines having a width corresponding to 14V are indicated by double-ended arrow lines. From Equation 3 and Equation 6, the lengths of the four lines are all the same.

  Here, as a battery configuration, it is assumed that a negative electrode having a characteristic of a current potential curve N11 is used as the negative electrode, and a positive electrode having a current potential curve P22 with improved charge acceptance performance is used as the positive electrode. Then, as is apparent from the figure, the charging current rises to I12 while keeping the charging voltage 14V as shown in equations 3 and 6. At this time, as discussed mathematically from the viewpoint of the principle, the overvoltage of the positive electrode is lowered and the absolute value of the overvoltage of the negative electrode is increased. Next, as a battery configuration, it is assumed that a positive electrode having the characteristics of the conventional current potential curve P11 is used for the positive electrode and a negative electrode having a current potential curve N22 with improved charge acceptance performance is used for the negative electrode. Then, as is apparent from the figure, the charging current rises to I21 while keeping the charging voltage 14V. At this time, as discussed so far, the overvoltage of the positive electrode increases and the absolute value of the negative electrode overvoltage decreases.

  On the other hand, a case where both the negative electrode and the positive electrode are improved as a battery configuration will be considered. That is, when the battery of the electrode plate having the current potential curves N22 and P22 is invented, the charging current rises to I22 while keeping the charging voltage 14V as shown in the equations 3 and 6. As shown in the discussion on the principle side, I22 indicates that the maximum charging current can be obtained in these examination examples.

  The linear relationship shown in Formula 11 shown in terms of basic characteristics of the electrochemical reaction is treated as a linear gradient extending from the vicinity of the equilibrium potential of the negative electrode and the positive electrode shown in FIG.

  As described above, the contents expressed by Expressions 1 to 11 are common to both liquid lead acid batteries and VRLA.

  As described above, in the discussion based on the mathematical and schematic methods, there is essential information that is overlooked in general voltage measurement. That is the overvoltage that is the essence of the present invention. As apparent from FIG. 1, in 14V constant voltage charging, as long as the relative potential difference between the negative electrode and the positive electrode is measured, the change in overvoltage between the negative electrode and the positive electrode is not visible. The reason is clear from Equation 3 and Equation 6, but FIG. 1 clearly shows this fact. In spite of the constant 14V in the voltage measurement, when the electrode plate configuration is changed, the overvoltage changes rapidly, and the charging current changes accordingly.

  Therefore, in the present invention, a measuring facility capable of separating overvoltage is required. It is an electrochemical measurement device, and it is necessary to construct an invention based on data using the electrochemical measurement device. Hereinafter, a specific configuration of the present invention based on the relationship between the overvoltage condition and the charging current will be clarified by the following procedure.

  First, the relationship between the charging current and the overvoltage of the negative electrode and the positive electrode of a conventional lead storage battery is measured. It is accurate to actually measure the current-potential curve with an electrochemical measurement facility that has both a potentiostat function and a galvanostat function. Potentiostats and galvanostats are electrochemical measuring devices that can separate overvoltages. The potentiostat can control the potential of the evaluation electrode with respect to the reference electrode, and can measure the current observed at the control potential. The galvanostat can control the current flowing through the evaluation electrode, and can measure the potential change of the evaluation electrode with respect to the reference electrode under constant current control. In terms of electrochemical measurement, it is simple and sufficient for evaluation to measure one positive electrode or one negative electrode corresponding to a single cell.

  Electrochemical measurement when the charging voltage is constant is equivalent to controlling the potential with respect to the potential of the reference electrode. That is, in the case of the negative electrode, the overvoltage is applied so that the potential becomes more negative from the equilibrium potential of the negative electrode. When the potential is controlled to be constant, the charging current of the lead-acid battery is attenuated with time except in the extremely short time region of the electric double layer charging process. Therefore, when defining the charging current based on the potential control, it is necessary to define how many seconds the current value is. In the case of monitoring the time variation of overvoltage by controlling the current, the absolute value of the overvoltage increases with the measurement elapsed time. These phenomena have long been known by electrochemical reaction rate theory. Whether the current is defined by controlling the potential, or the overvoltage (potential) is defined by controlling the current, the obtained current-potential curve is obtained based on the current in the second or overvoltage data in the second. It must be defined whether it is In the present invention, these time windows are defined as the current or overvoltage at the 5th second after the start of charging. The temperature is 25 ° C.

  It is necessary to define the state of the battery. When defining battery characteristics with respect to cycle deterioration, conditions such as what cycle and what cycle pattern are necessary. In the present invention, regarding the charge acceptance condition 1.5 times that of the conventional battery, necessary conditions are defined for the relationship between the overvoltage, the current, and the current density regarding the initial state of the battery.

  Unless otherwise specified, the electrolyte specific gravity is represented by the initial specific gravity for both the liquid lead acid battery and VRLA.

  In the present invention, each active material condition regarding the current potential curve of the negative electrode and the positive electrode of the conventional battery needs to be clearly defined. This is because the current-potential curve, that is, the necessary conditions related to overvoltage and current density are all shown with reference to those of the negative electrode and the positive electrode of the conventional battery defined in the present invention. Details of the negative electrode and positive electrode conditions of the conventional battery are shown in the Examples.

  As can be seen in FIG. 1, the measured current-potential curve for one negative electrode and one positive electrode of a conventional lead-acid battery has a potential vs. horizontal axis. The reference electrode (usually SHE) is represented by the absolute value of the current on the vertical axis. The charge acceptance performance per unit cell can be obtained by using a drawing relating to the obtained current-potential curve or by calculation. When using the figure, it is nothing but the content discussed in FIG.

In the case of obtaining by calculation, for example, in the case of a conventional battery, an approximate expression representing the current potential curves of N11 and P11 shown in FIG. 1 is obtained in advance. The obtained approximate expression corresponds to Expression 5. Equation 3 corresponding to a 2V single cell is expressed by Equation 12 below. Equation 12 is 0.333 V / single cell.
(| Η (−) | + | η (+) |) / 6 = (14−12) / 6.
From the equations 5 and 12, the overvoltages relating to N11 and P11 in FIG. 1 can be obtained by solving simultaneous equations. If the overvoltage applied to the negative electrode and the positive electrode is obtained, the charge acceptance current or current density can be obtained from Equation 5.

  Next, the current-potential curve is measured in the same manner for the negative electrode active material with improved charge acceptance performance. In FIG. 1, it is a current-potential curve N22. Further, the current-potential curve of the improved positive electrode active material is measured. In FIG. 1, it corresponds to P22.

  Based on these data, the condition of the present invention is that the charge acceptance performance of a lead storage battery mounted on an ISS vehicle is 1.5 times or more that of a conventional lead storage battery. That is, referring to FIG. 1, first, I11 and I12 are compared, and it is confirmed whether I12 exceeds 1.5 times with respect to I11. Similarly, information on I21 and I22 is confirmed for I11.

  One of the facts revealed in the principle of the present invention is that, as long as a conventional negative electrode is used, no matter how much the positive electrode is improved, there is no overvoltage condition of 1.5 times the charging current. That is, it is a fact that the charge current cannot be increased 1.5 times by improving only the positive electrode. This fact is a result of clearly supporting from the overvoltage aspect the conventional idea that the improvement of the negative electrode has been regarded as the key to improving the charge acceptance performance. Therefore, the basic overvoltage requirement of 1.5 times the charging current is the negative overvoltage condition, and the combination of the improved negative electrode and the improved positive electrode has the maximum charge acceptance condition.

  In the VRLA according to the present invention, in order to improve the performance of the negative electrode plate, at least the carbonaceous conductive material and the organic compound that maintains the coarsening suppression of the negative electrode active material and the reaction surface area accompanying charge / discharge are included in the negative electrode active material. Added.

  The carbonaceous conductive material is preferably selected from a material group consisting of graphite, carbon black, activated carbon, carbon fiber, and carbon nanotube. Of these, graphite is preferable, and scaly graphite is preferably selected. When using flaky graphite, the average primary particle diameter is preferably 100 μm or more. The addition amount of the carbonaceous conductive material is preferably in the range of 0.1 to 3 parts by mass with respect to 100 parts by mass of the fully charged negative electrode active material (also referred to as porous metallic lead or spongy metallic lead). The scaly graphite refers to that described in JIS M 8601 (2005).

  In addition, by adding an organic compound that suppresses the coarsening of the negative electrode active material associated with charge / discharge to the negative electrode active material and optimizing the amount added, the charge / discharge reactivity is not impaired for a long period of time, and charging is accepted. It is possible to obtain a negative electrode plate that can maintain a state with high properties for a long period of time.

  As described above, it is possible to improve the charge acceptability of the entire battery simply by adding the carbonaceous conductive material and the organic compound that suppresses the coarsening of the negative electrode active material to the negative electrode active material to improve the performance of the negative electrode plate. However, by combining this negative electrode plate with the positive electrode plate described above, the charge acceptability of the entire battery can be further improved.

  As the organic compound that suppresses the coarsening of the negative electrode active material, it is preferable to use bisphenols, aminobenzenesulfonic acid, and formaldehyde condensates. Examples of the bisphenols include bisphenol A, bisphenol F, and bisphenol S. Of the condensates, the bisphenol A / sodium benzenebenzene / formaldehyde condensate represented by the chemical structural formula of [Chemical Formula 1] is particularly preferable.

  As described above, the charging reaction of the negative electrode active material depends on the concentration of lead ions dissolved from lead sulfate, which is a discharge product, and the charge acceptance increases as the amount of lead ions increases. Lignin is widely used as an organic compound added to the negative electrode active material in order to suppress the coarsening of the negative electrode active material associated with charge / discharge. Since lignin is adsorbed to lead ions and decreases the reactivity of lead ions, it has the side effect of inhibiting the charge reaction of the negative electrode active material and suppressing the improvement of charge acceptability. In contrast, the bisphenol A / sodium aminobenzenesulfonate / formaldehyde condensate having the chemical structural formula of [Chemical Formula 1] has a weak adsorptive power to lead ions and has a small amount of adsorption. When the condensate is used, the charge acceptability is less likely to be hindered, and the charge acceptability due to the addition of the carbonaceous conductive material can be maintained.

  The present invention does not prevent selection of sodium lignin sulfonate or the like represented by the chemical structural formula (partial structure) of [Chemical Formula 2] as an organic compound that suppresses the coarsening of the negative electrode active material associated with charge / discharge. . Although sodium lignin sulfonate is frequently used as an organic compound that suppresses the coarsening of the negative electrode active material, it has a drawback that it has a strong adsorption power to lead ions and has a strong side effect of suppressing a charging reaction. In contrast, bisphenols, aminobenzene sulfonic acid, and formaldehyde condensates have a weak adsorption capacity to lead ions and are less likely to be adsorbed by lead ions. Will not be disturbed.

  First, the present invention clarifies the condition that the charge acceptance performance is 1.5 times or more under the condition of the liquid lead-acid battery. Based on this, the condition for making the charge acceptance performance of VRLA 1.5 times or more is clarified. When the active material conditions and current collector conditions of the liquid lead acid battery and the positive and negative electrodes of VRLA are made common, the electrolyte concentration of VRLA is higher than that of the liquid lead acid battery. The relationship between the charge acceptance performance of a liquid lead-acid battery of 1.5 times or more and the condition of 1.5 times or more of the VRLA charge acceptance performance depends on the difference in sulfuric acid concentration of the electrolyte on the charge acceptance speed. Shown by quantification. In order to clarify the relationship between the condition of the liquid lead-acid battery and the condition of the VRLA with respect to the condition that the charge acceptance performance is 1.5 times or more, first, the relationship between the charge reaction rate of the negative electrode and the sulfuric acid concentration or specific gravity of the electrolyte is determined. Quantify using parameters related to the theoretical charging reaction.

Basically, it is considered that the charging reaction of the negative electrode of the lead-acid battery is composed of the following two reactions.
PbSO ₄ → Pb ²⁺ + SO ₄ ²⁻ speed k ₁ ...
Pb ²⁺ + 2e → Pb velocity k ₂ ...
Equation 13 is a dissolution reaction of Pb ²⁺ ions from lead sulfate, and Equation 14 shows a so-called charging reaction of Pb ²⁺ ions. In general, the total reaction formula 15 obtained by adding the formula 13 and the formula 14 represents the negative electrode reaction, and the negative electrode potential determination reaction is the formula 15. However, the charge reaction rate must be determined by quantifying the relationship of Equations 13 and 14.
Total reaction: PbSO ₄ + 2e → Pb + SO ₄ ² −... Formula 15
Here, k ₁ is the Pb ²⁺ ion source (Flux), and the dimension is mol / cm ² s. From Electrokinetic Kinetics (Theorem of Electrochemical Kinetics)
k ₂ = k ⁰ exp [− (2αF / RT) (E−E ⁰ )] (cm / s).
Here, k ⁰ : standard rate constant (cm / s) (Standard Rate Constant), α: transition coefficient (F), F: Faraday constant (C / mol) (Faraday Constant), R: gas constant (J / Kmol) (Gas Constant), T: Absolute temperature (K) (Ebsolute Temperature), E: Potential vs. Standard hydrogen electrode potential (NHE) (Normal Hydrogen Electrode), E ⁰ : Standard electrode potential of formula 14 (−0.126 V) vs. NHE.

From the equations (13) and (14), the following general relational expressions relating to mass transfer, initial conditions, and boundary conditions relating to the charge reactive species are established. Analysis is performed under steady-state conditions from Equation 18.
∂C _A / ∂t = D _A (∂ ² C _A / ∂x ² )... Equation 16
D _A (∂C _A / ∂x) _{x = 0} = k ₂ C _AS −k _1.
∂C _A / ∂t = 0 ........... 18
x = 0 → C _A = C _AS ... Equation 19
x = δ → C _A = C _A0 ... Equation 20
t = 0 → C _A = C _A0 ... Equation 21
Here, C _A : Pb ²⁺ ion concentration (mol / cm ³ ), D _A : Pb ²⁺ ion diffusion coefficient (cm ² / s), C _AS : Pb ²⁺ ion charge reaction interface concentration (mol / cm ³ ) , C _A0 : initial concentration before charge of Pb ²⁺ ions (mol / cm ³ ), δ: diffusion layer thickness (cm) of Pb ²⁺ ions (Diffusion Layer). The charging current i (A) is expressed by Equation 22 below.
i (A) = 2SFk ₂ C _AS Expression 22
Here, S is the total reaction area effective for the negative electrode charging reaction.

As described above, the theoretical current-potential curve relating to the negative electrode charging reaction is obtained by obtaining C _AS from Equation 16 to Equation 21 and substituting it into Equation 22. The theoretical charging current equation 22 to be obtained becomes the following equation 23.
i (A) = 2SFk ⁰ exp [− (2αF / RT) (E−E ⁰ )] [(k ₁ + (D _A / δ) C _A0 ) / (k ⁰ exp [− (2αF / RT) (E −E ⁰ )] + (D _A / δ))] Equation 23
The charging current i (A) expressed by Equation 23 is basically a function of potential, but is affected by C _A0 , which is the initial concentration of Pb ²⁺ ions before charging, at each potential. That is, if the initial concentration of Pb ²⁺ ions before charging is doubled, the charging speed is doubled. k ₁ is the smaller value is a constant. The exact value of k ₁ is currently unknown, but there is no doubt that this value is small. This is because the lead storage battery has a low charging speed. If the value of the k ₁ is greater, the lead-acid battery is a battery having a high input performance needs of the present invention will become unclear. Therefore, it is considered that the charging speed i (A) under the high-speed charging condition of the ISS car is determined by the magnitude of the initial concentration of Pb ²⁺ ions before charging, C _A0 .

Therefore, if the relationship between the specific gravity of the sulfuric acid electrolyte and the initial concentration of the Pb ²⁺ ions before charging is obtained, the conditions for increasing the charge acceptance performance of the liquid lead acid battery to 1.5 times or more and the charge acceptance performance of VRLA 1 The relationship between the conditions of 5 times or more becomes clear. As shown in Formula 13, Pb ²⁺ ions are generated by dissolution and dissociation of lead sulfate. Therefore, if the relationship between the Pb ²⁺ ion concentration under each sulfuric acid specific gravity is known, the relationship of 1.5 times or more of the charge acceptance performance of VRAL can be found using the current-potential curve of the liquid lead acid battery.

FIG. 2 shows the relationship between the concentration of Pb ²⁺ ions at 25 ° C. and the specific gravity of sulfuric acid electrolyte (Hans Board “Lead-Acid Batteries” p. 27, (1977), John Wiley & Sons Inc.). The lead storage battery basically has no Pb ²⁺ ions necessary for the charging reaction, as is apparent from Equation 13, when there is no lead sulfate. In the present invention, as shown in the first embodiment, the charge acceptance performance is evaluated under the condition that 90% of the state of charge (SOC), that is, 10% of the capacity is discharged. As shown in FIG. 2, when the capacity of the VRLA having an electrolyte specific gravity of 1.320 is discharged 10% in a fully charged state and reaches 90% in the charged state, the electrolyte specific gravity decreases to 1.292. On the other hand, in a fully charged state, a liquid lead acid battery having an electrolyte specific gravity of 1.280, when the S charge state reaches 90%, the electrolyte specific gravity decreases to 1.267. From FIG. 2, the concentration of Pb ²⁺ ions with respect to the electrolyte specific gravity of 1.292 and 1.267 can be obtained. The concentration of Pb ²⁺ ions is 1.08 (mg / liter) at an electrolyte specific gravity of 1.292 and 1.28 (mg / liter) at an electrolyte specific gravity of 1.267. Therefore, when the state of charge is 90%, the concentration of C _A0 in Formula 23, that is, Pb ²⁺ ions, is 1.19 times that of the VRAL in the liquid lead acid battery. Therefore, the charging speed of the liquid lead acid battery is considered to be 1.19 times VRAL under this condition.

The same applies when the state of charge is reduced to 80%. The initial specific gravity 1.320 of VRAL is reduced to 1.270, and the initial specific gravity 1.280 of the liquid lead acid battery is reduced to 1.254. Similarly, when the concentration of Pb ²⁺ ions at the electrolyte specific gravity of 1.270 and 1.254 is determined from FIG. 2, they are 1.25 and 1.40 (mg / liter), respectively. Therefore, when the state of charge is 80%, the concentration of C _A0 in Formula 23, that is, Pb ²⁺ ions, is 1.12 times that of the liquid lead acid battery. Therefore, the charge rate of the liquid lead-acid battery is considered to be 1.12 times VRAL under this condition.

  In the liquid lead acid battery and the VRAL, the electrolyte specific gravity changes as described above depending on the discharge state. Therefore, the electrolyte specific gravity of the lead acid battery is typically represented by a specific gravity of 100% in the charged state.

  In the present invention, as shown by Expression 11, a region that can be linearly approximated is set with respect to the relationship between the initial charging current and the overvoltage of the current-potential curve, and a gradient corresponding to | η | / | i | is obtained. Thus, first, with respect to the liquid type lead-acid battery, the charging current 1.5 times with respect to overvoltage and current, and the conditions exceeding 1.5 times are defined. Based on these, the conditions regarding VRAL will be clarified. Specifically, based on the general formulas, Formulas 7 and 8, it is achieved by developing an active material that gives a current-potential curve satisfying Formula 7 with respect to the current-potential curve of the negative electrode and the positive electrode using the conventional active material. Become. | Η | / | i | is determined from a region where the current potential curve satisfying Equation 7 can be linearly approximated.

From FIG. 2 and Expression 23, Expression 24 can be obtained from the relationship between | i (−) | _Flood and | i (−) | _VRLA . | I (−) | _Flood indicates the absolute value of the charging current of the negative electrode of the liquid lead-acid battery, and | i (−) | _VRLA indicates the absolute value of the charging current of the negative electrode of VRLA.
| I (−) | _Flood = β | i (−) | _VRLA Expression 24
Here, β is a dimensionless coefficient. From the above examination result, β = 1.19 in the charged state 90%. It means that it is 0.84 times (1 / 1.19) of VRLA with respect to the charge rate of the liquid lead-acid battery with the same active material paste and the same grid body specifications.

Here, Equation 23 assumes a steady state based on Equation 18 assuming that the initial Pb ²⁺ concentration is constant regardless of time. The validity of this assumption holds in principle especially in the initial stage of charging. This is because the consumption amount of Pb ²⁺ is still small at the initial stage of charging, and a value close to the initial concentration shown in FIG. 2 is maintained. Due to the charging reaction, Pb ²⁺ is consumed over time, and the concentration decreases. The decrease in concentration theoretically increases as the initial concentration of Pb ²⁺ increases. As shown above, β is 1.19 when the state of charge is 90%, but the concentration difference of Pb ²⁺ ions decreases with time, and β can be expected to be lower than 1.19.

Equation 23 is a charge kinetic equation derived under linear diffusion conditions for Pb ²⁺ ions. However, the reaction field in the active material of an actual lead storage battery has many pores and forms a complex reaction field. For this reason, it is difficult for the charge rate equation considering time dependency to cover all the time regions only by linear diffusion. Equation 23 holds in principle even in such a complex reaction field in a short time region after the start of the charging reaction.

  Therefore, it is necessary to confirm on the basis of actual measurement data how many seconds after the start of charging it is appropriate to handle the equation (23). At least in a short time region after the start of charging, the value of β = 1.19 in the charged state 90% should hold in principle.

As Table 2 in Example 1 shows, β in the charging state 90% is β = 1.19 ₅ in an actual measurement value 1 second after the start of charging. The value of 5 seconds after the start of charging is beta = 1.11 _1. The first second is in agreement with the value calculated from the theoretical formula and the concentration of Pb ²⁺ ions. As expected, β decreases at 5 seconds. In the present invention, as shown in Example 1, | η | / | i | evaluation is examined based on information on a current-potential curve at 5 seconds after the start of charging. The time condition of 5 seconds is a realistic time region in which the actual driving environment of the ISS vehicle and the brake regeneration time are related. In other words, the lead-acid battery continues to be charged while the brake is being depressed. In the present invention, based on the above-described principle background, the experimental value β = 1.11 at the fifth second after the start of charging is used.

From Expression 24, when | i (−) | _{Flood of} the liquid lead-acid battery is determined, | i (−) | _VRLA is determined. From these relationships, the following relationship regarding 1.5 times charging current regarding overvoltage and current is obtained. That is, when the expression 25, | η (−) | / | i (−) | _Flood for the liquid lead-acid battery is determined, the expression 26, | η (−) | / | i (−) | _{VRLA for VRLA} is determined. Here, | η (−) | indicates the absolute value of the overvoltage corresponding to the charging current of each negative electrode.
| Η (−) | / | i (−) | _Flood Expression 25
| Η (-) | / | i (-) | VRLA = β | η (-) | / | i (-) | Flood ········ formula 26
The same applies to the charging reaction of the positive electrode. Similarly to the charging reaction of the negative electrode, the lead sulfate dissolution reaction represented by the formula 13 exists as a preceding chemical reaction of the electrochemical reaction represented by the formula 27.
PbSO ₄ → Pb ²⁺ + SO ₄ ² −... Equation 13
Pb ²⁺ + 2H ₂ O → PbO ₂ + 4H ⁺ + 2e
The charge reaction rate of the positive electrode is basically the same as that of Equation 23 under the same conditions as shown in Equations 16 to 21. The relational expressions regarding the negative electrode, the relational expressions of the positive electrode corresponding to the expressions 24, 25, and 26 are defined by the following expressions 28, 29, and 30.
| I (+) | _Flood = β | i (+) | _{VRLA
| Η (+) | / |} i (+) | Flood ········· formula 29
| Η (+) | / | i (+) | VRLA = β | η (+) | / | i (+) | Flood ········ formula 30
Here, | i (+) | _Flood is the absolute value of the charging current of the liquid positive electrode, and | i (+) | _VRLA is the absolute value of the charging current of the positive electrode of VRAL. | Η (+) | indicates the absolute value of the overvoltage corresponding to the charging current of each positive electrode. The coefficients β in Equation 24 and Equation 28 are the same in terms of the charging reaction mechanism of the negative electrode and the positive electrode. Β of 5 seconds after the start of charging is β = 1.11 as in the negative electrode.

  Quantitative handling of the negative electrode and positive electrode charge kinetics is the same when the conditions for the negative electrode active material, positive electrode active material, and current collector structure are the same for both liquid lead-acid batteries and VRAL, and only the electrolyte specific gravity is changed. The above conditions are basically established. This is also clear from the results shown in Example 1 and Table 2.

First, | η (−) | / | i (−) | _Flood , | η (+) | / | i (+) | _Flood in a liquid lead-acid battery is clarified. From these values and Equations 26 and 30, the VRAL charging current is 1.5 times and the condition exceeding 1.5 times is clarified.

  The battery charge acceptance test, that is, the charge current evaluation test condition in the present invention is as follows unless otherwise specified. That is, when the charge acceptance test is performed at a temperature of 25 ° C., the charge current limit current is 200 A, 14 V constant voltage, and the state of charge (SOC) is 90%, the charge current of the fifth second after the start of constant voltage charge is Evaluate by value. The specific gravity of the electrolyte (specific gravity in the fully charged state before SOC adjustment) is 1.28 for a liquid lead acid battery.

  As a conventional liquid lead acid battery, the battery characteristics of an 80D23 type lead acid battery defined by JIS are shown. That is, the initial charge acceptance performance of the 80D23 type lead-acid battery is 33 ± 2 A level as the charge current at the start of 14 V constant voltage charge at the 5th second. The essential characteristics of this battery are revealed by the following electrochemical measurements. That is, the characteristics of the 2V single cell, which is the minimum structural unit of the battery, will be clarified by electrochemical measurement. The measurement temperature (electrolytic solution) is 25 ° C. unless otherwise specified.

  The state of the active material in the charge acceptance test is assumed to be the initial state. That is, the active material of the negative electrode and the positive electrode is applied to the current collector, and after aging, chemical conversion, and the like, the charge acceptance characteristics of the active material adjusted to a predetermined SOC or the like. It is not a charge acceptance characteristic in the middle of a cycle test or in a battery deterioration state. Except for the cycle evaluation test, the charge acceptance test evaluation such as the 1.5-fold condition in the present invention is a characteristic in a state where such deterioration is not manifested.

  The measurement conditions of the current-potential curve in the present invention are as follows. The current-potential curve is measured using a single plate, that is, one evaluation electrode plate for each of the negative electrode and the positive electrode. This is so-called electrochemical measurement of a single cell 2V system and one evaluation electrode plate. A single cell is a minimum unit of a lead storage battery corresponding to one series of 6 series 12V batteries. Electrochemical measurement must be performed with a potentiostat or galvanostat function. Electrochemical measurement uses an electrochemical measurement cell composed of a normal three-electrode system in which one evaluation electrode plate (working electrode) and one counter electrode are provided with a lugin capillary (Luggin capillary). An easy-to-handle mercuric sulfate reference electrode was placed in the Lugin capillary to serve as a reference electrode for electrochemical measurements. The standard electrode potential of the mercuric sulfate electrode was +0.615 V vs. standard hydrogen electrode potential (SHE). SHE. Therefore, the relationship between the current potential measured at the mercuric sulfate electrode can be easily converted to SHE.

  In the case of electrochemical measurement in a single cell, the voltage corresponding to the 14V charging voltage is 2.333V.

  After adjusting the SOC of the electrochemical measurement cell to 90% (discharge at a temperature of 25 ° C. and 0.2C for a capacity of 10%), after confirming that the equilibrium potential of the evaluation electrode plate is stable with respect to the reference electrode, The curve was measured. As a guideline for stabilizing the equilibrium potential, the potential fluctuation was set within ± 0.5 mV. Before the equilibrium potential measurement, the dissolved oxygen in the electrolyte was degassed with nitrogen, and the electrochemical measurement was performed in a nitrogen atmosphere without stirring the electrolyte. The current-potential curve is measured based on the current at the fifth second in the case of potential control and the potential at the fifth second in the case of current control. After the measurement of the current-potential curve of the target evaluation electrode plate is completed, the ohmic loss (IR drop) between the Luggin capillary and the evaluation electrode plate is measured, and the true current obtained by subtracting the IR loss from the obtained current-potential curve The relationship between potential and current was obtained and used as the final current-potential curve. The ohmic loss measurement conditions were a frequency of 1 kHz, and a potential fluctuation range from the equilibrium potential was 10 mV, Peak to Peak. These are the contents of measurements that are normally performed when obtaining an accurate current-potential curve in normal electrochemical measurements.

FIG. 4 shows the details of the current collector of the electrode plate for current potential curve measurement. An active material was applied to the expanded current collector shown in FIG. 4 for both the negative electrode and the positive electrode, and a current-potential curve was measured. In electrochemical measurement, an electrode plate of a B-type lead storage battery that is smaller than an electrode plate of a D-type lead storage battery defined by JIS is also preferable in terms of electrochemical measurement and the measurement capability of the electrochemical measurement equipment. The projected area of the active material application portion shown in FIG. 4 is 108 cm ² . The combined area of both sides is 216 cm ² .

  In electrochemical measurement, current density display is often used to display a current-potential curve. However, there are difficult aspects when evaluating an actual battery. That is, the reaction active material having many pores has an actual reaction area larger than the actual projected area, and the configuration of the number of the negative electrode and the positive electrode plate in the actual battery is often not the same. This makes it difficult to define the current density in the evaluation of a practical battery having a porous battery active material. In the cell configuration for electrochemical measurement in the present invention, the Lugin capillary is installed only in one direction of the electrode plate, and the opposite surface of the evaluation electrode plate is a normal electrode plate without any insulating seal. In such a state, the wraparound of the current from the evaluation electrode plate on the surface opposite to the counter electrode becomes smaller due to the solution resistance. However, it is clear that current flows from the back surface of the evaluation electrode plate. In this case, the meaning of current density is ambiguous. Also in the actual battery, in the case of a parallel configuration of 6 positive electrodes and 7 negative electrodes, there is no opposing electrode plate on the electrode plate surfaces at both ends. Again, how to evaluate the reaction area is not simple.

  In the electrochemical measurement in the present invention, from such a viewpoint, the observed current value is used as the total current value for evaluation. From the viewpoint of electrochemical reaction kinetics, the relationship between overvoltage and current shows the relationship between current density and overvoltage when the ohmic loss is corrected (Yuta Tamamushi, “Electrochemistry (2nd edition)” p. 236, (1991), Tokyo Chemical Doujin). Theoretically, in the current-potential curve, since the same current density is the same overvoltage, it can be considered that the overvoltage does not change even when evaluated with all currents that change depending on the size of the area of the electrode plate. For example, in the electrochemical measurement shown in the present embodiment, measurement is performed with one counter electrode facing one evaluation electrode plate. If two counter electrodes are installed on both sides of the evaluation electrode plate and electrochemical measurement is performed, the observed current increases. This is because the reaction area is substantially increased and the counter electrode is provided on both the front and back of the evaluation electrode plate, so that the observed current increases. However, as a result, the current increased by increasing the reaction area is the same in the case of current density display obtained by dividing the total current by the reaction area. Therefore, the electrochemical measurement conditions for obtaining the current-potential curve must be performed under the same conditions.

  FIG. 3 shows a measured current potential curve (N1, N3, P1, P3) in which the results of electrochemical measurement are arranged, and a current potential curve (N2, P2) relating to a threshold value that gives a charging current of 1.5 times or more. It is a current-potential curve obtained with one evaluation electrode plate and one counter electrode. When the current potential curve of FIG. 3 is used for one evaluation electrode plate and two counter electrodes are used on both surfaces thereof, the current value shown in FIG. 3 increases. However, since the overvoltage is theoretically related to the current density as described above, even when the current value shown in FIG. 3 changes, the overvoltage condition that is an essential parameter of the present invention is theoretically. Is considered equivalent. This is an important point, and even if the area of the electrode plate is changed, overvoltage conditions can be disclosed in principle regardless of the size of the electrode plate if the same active material is used. Therefore, in the case of the same electrochemical measurement cell configuration (one evaluation electrode plate and one counter electrode) in which the ohmic loss shown in the present invention is corrected, an equivalent overvoltage condition is shown in principle.

  The handling of the charging current is the same even when the battery is configured. The battery is an 80D23 type lead-acid battery (a single plate is composed of 6 plates of positive electrodes and 7 plates of negative electrodes), and the charging current in the 5th second at the time of 14V constant voltage charging is about 33A. If the number of electrode plates is increased or decreased to 9 positive electrodes, 10 negative electrodes, 4 positive electrodes, 5 negative electrodes, etc., the charging current increases or decreases from 33A accordingly. Alternatively, even if the B-type lead storage battery is configured with the active material of the electrode plate of the 80D23-type lead storage battery, or the battery larger than the 80D23-type lead storage battery is configured, the charging current becomes smaller or larger than 33A. . However, the overvoltage relationship shown in FIG. 3, that is, the overvoltage distribution condition for the charging voltage single cell 2.333 V, basically does not move.

  In FIG. 3, N1 and N3 are measured current-potential curves related to the negative electrode, and P1 and P3 are measured current-potential curves related to the positive electrode. The estimated current electric potential curve regarding the threshold value in which N2 and P2 give a charging current 1.5 times or more to the conventional battery is shown. N1 and P1 are current-potential curves for the conventional negative electrode and the conventional positive electrode, respectively. N3 is an example of the present invention relating to an improved negative electrode and P3 is an improved positive electrode.

  With the combination of the conventional electrode plates (N1 / P1) shown in FIG. 3, a charging current of 5.40 A is observed.

  In the present invention, the definition of overvoltage using a conventional active material is as follows. As seen in FIG. 3, the negative electrode current-potential curve N1 has a great feature as a conventional negative electrode. That is, the current-potential curve is greatly inflected (point X2 in the figure) in the low charging current region. Overvoltage rises greatly at the 7A level charging current, and shifts to hydrogen gas generation. That is, since there is not a sufficient charge reaction rate, the overvoltage suddenly increases. Thus, it can be confirmed that the conventional negative electrode is clearly different from the conventional positive electrode P1 and the improved negative electrode N3. In other words, the conventional charge acceptance performance is dominated by the negative electrode. From this, the conventional active material of a positive electrode can follow the definition of the conventional negative electrode active material.

As described above, the conventional active material in the present invention has an electrode plate with an active material application projected area of 108 cm ² as an evaluation electrode plate, and, as an electrochemical measurement condition, has one counter electrode in the form of facing one side of one evaluation electrode plate. This is an electrochemical measurement system provided with a reference electrode serving as a potential reference in the meantime, and is defined based on the measurement result of the charging current for a single cell charging voltage of 2.333 V (= 14 V / 6) and the current-potential curve for overvoltage. .

  That is, the point X1 (the overvoltage is zero and the charging current is about 1 A) at which the absolute value of the charging overvoltage with respect to the single cell charging voltage 2.333V starts to increase from zero is the origin, and the inflection point X2 ( point of inflection), that is, the current value in the region of about 7 A, and the slope of the overvoltage (η (mV)) and the charging current (A) related to Equation 11 are expressed by linear approximation. Each gradient of the active material is as follows. That is, the conventional negative electrode active material has an N1 gradient of 25.6 (mV / A) giving a current-potential curve. In the conventional positive electrode active material, the slope of P1 giving a current-potential curve is 17.7 (mV / A). The slope of the overvoltage and current plot in the present invention shown in Equation 11 is the slope related to the overvoltage and current of the current potential curve observed in the current region of the charging current of 7 A or less under the measurement conditions of the current potential curve of the present invention. FIG. 3 is a total current display.

  Hereinafter, the implementation results and conditions for obtaining a charging current 1.5 times that of the conventional battery will be clarified.

  FIG. 3 shows various current-potential curves N1, N2, N3, P1, P2, and P3, as well as the conditions for providing a charging current of 1.5 times or more and the contents regarding various overvoltages. Current-potential curves N2 and P2 are estimated current-potential curves necessary to give the conventional battery charging current 1.5 times and 1.75 times, respectively. N3 and P3 are measured current potential curves of the negative electrode and the positive electrode satisfying the actual charging current doubled and the condition exceeding the doubled shown in the present invention.

  Table 1 shows the JIS standard 80D23 type lead acid battery using the improved negative electrode active material and the improved positive electrode active material based on the measured current potential curves N3 and P3 of the negative electrode and the positive electrode that actually satisfy the charging current 1.5-fold condition. The data which measured the charge acceptance performance are shown. A side-by-side comparison with conventional batteries was made. It is thought that the characteristic result considered from the current-potential curve of FIG. 3 can be reflected. The improved battery 1 is a (N3 / P1) battery in which a current potential curve N3 with an improved negative electrode and a conventional positive electrode P1 electrode plate are combined. The improved battery 2 corresponds to a combination (N3 / P3) of electrode plates of the improved negative electrode current potential curve N3 and the improved positive electrode current potential curve P3. The electrode plate group configuration of the battery shown in Table 1 is a configuration of 6 positive electrodes and 7 negative electrodes of 80D23 type lead storage battery of JIS standard for all of the conventional product, the improved battery 1 and the improved battery 2. The current sampling time is 1, 2, 3, 5, 10 seconds, and the charging current is displayed by dividing the battery capacity 52Ah by the current 52A. Therefore, when the charging current is set to 52 A during a certain current sampling, the current display is 1.00. Looking at the current at 5 seconds, the improved battery 1, that is, the combination of N3 and P1 (N3 / P1) in FIG. 3, obtains a charging current 1.81 times that of the conventional battery. I understand. This value is close to the value estimated from the combination of N3 and P1 in FIG. The current-potential curve in FIG. 3 is obtained by correcting the ohmic loss, but various ohmic losses are included as they are in the charging voltage observed in the actual battery. For this reason, considering that the magnification estimated from the combination of N3 and P1 in FIG. 3 is nearly twice, the 1.81 times shown in the actual battery is sufficiently consistent with the relationship of the current-potential curve. Conceivable. It can be seen that the improved battery 2, that is, the combination of N3 and P3 (N3 / P3) in FIG. 3, obtained a charging current of 2.34 times in the 5th second compared to the charging current of the conventional battery. This value is also considered to be sufficiently consistent with the charge acceptance performance estimated from the relationship between N3 and P3 shown in FIG. The (N3 / P3) battery is a combination that can be expected to improve the maximum charging current, as shown in FIG.

Table 2 shows the result of measuring the charging current in the improved battery 2 (N3 / P3) under the condition of the electrolyte specific gravity of 1.28 of a normal liquid lead acid battery and the condition of the electrolyte specific gravity of 1.32 of VRLA. . The charging current at 1 second and 5 seconds after the start of charging is shown. As in Table 1, the charging current value is divided by the battery capacity 52A. The value of β defined by Equation 24 is shown based on experimental results. Β in the short time region is estimated from Equation 23 to be theoretically β = 1.19, but the value of the first second in Table 2 matches the estimated value. Furthermore, it is shown as a value at the fifth second that β decreases with time. For β at the 5th second, β = 1.11 shown in Table 2 is used, and | η (−) | / | i (−) | _VRLA and | η (+) | / | i (+) | _VRLA To clarify.

  N1 (VRLA) and P1 (VRLA) shown in FIG. 3 indicate the relationship between current and potential based on the calculation obtained by using β = 1.11 and Equations 24 and 28. N1 (VRLA) indicates the region up to the X2 inflection point.

  In the following, based on the implementation results of the present invention, the basic conditions of charging current 1.5 times, the threshold conditions, and the current-potential curves N3 and P3 in FIG. Show details. Based on these liquid lead-acid battery results, the overvoltage (mV) / charge current condition for VRLA is shown using Equation 26, Equation 30, and the value of β at 90% of SOC 90%, β = 1.11.

The following (a1) to (a6) are the equilibrium potential, open circuit voltage, total overvoltage, overvoltage distribution to the negative electrode, and overvoltage (mV) / charging current regarding the single cell negative electrode and the positive electrode of the conventional liquid lead acid battery. (Area of about 7 A or less, about 1 A (X1) or more). Hg / Hg ₂ SO ₄ is a mercuric sulfate reference electrode.
(A1) Equilibrium potential of conventional electrode Positive electrode: 1.170 V vs. Hg / Hg ₂ SO ₄ (reference electrode)
Negative electrode: -0.965 V vs. Hg / Hg ₂ SO ₄
(A2) Open circuit voltage 1.170+ | −0.965 | = 2.135V
(A3) Voltage applied to a single cell at a 14.0V charging voltage 14.0V / 6 = 2.333V
(A4) Total overvoltage applied to a single cell 2.333-2.135 = 0.198V
(A5) Overvoltage absolute value distribution to the negative and positive electrodes (from Fig. 3)
Negative electrode η (−) = 119 mV
Positive electrode η (+) = 79 mV
(A6) Overvoltage (mV) / charging current N1 current-potential curve slope (mV / ampere) = 25.6
The slope of the P1 current potential curve (mV / ampere) = 17.7
Therefore, when all the specifications of the negative electrode active material, the positive electrode active material, and the lattice are made common, and the initial specific gravity of the electrolyte is changed from the liquid lead acid battery condition 1.28 to the VRLA condition 1.32, the conventional N1, P1 The slope of the current-potential curve that gives is as follows from Equation 26, Equation 30, and β = 1.11.
(A7) VRLA overvoltage (mV) / charge current N1 (VRLA) slope of current-potential curve (mV / ampere) = 28.4
The slope of the P1 (VRLA) current-potential curve (mV / ampere) = 19.6
Hereinafter, first, the conditions satisfying the charging current of 1.5 times or more of the liquid type lead acid battery are shown. Based on the results of the liquid type lead acid battery, the charging current 1 of VRLA is obtained from the equations 26, 30 and β = 1.11. Indicates a requirement that satisfies 5 times or more. Details are as follows.

(B1) Improvement of negative electrode: 1.5-fold The combination in which only the negative electrode is improved, the positive electrode is a conventional positive electrode, and the charge acceptance performance is 1.5 times or more that of a conventional battery is shown in FIG. 3 (N2 / P1 ). That is, the gradient (improved negative electrode overvoltage / charging current) when the overvoltage and the charging current relating to a combination of these current potential curves are linearly approximated is as follows. Note that the origin of the N2 gradient is X0 where the overvoltage is zero and the charging current is zero.

N2 improved negative electrode overvoltage (mV) / charging current ≦ 9.4
P1 conventional positive electrode overvoltage (mV) / charge current = 17.7
The overvoltage absolute value of the improved negative electrode, N2 in FIG. 3, is 74 mV, while the overvoltage applied to the conventional positive electrode P1 is 124 mV.

  For the conventional negative electrode, N1 conventional negative electrode overvoltage (mV / charge current (about 7 A or less, region of about 1 A (X1) or more)) = 25.6. It is necessary to reduce the slope (mV / ampere) of the potential curve from 25.6 to 9.4, and the slopes for the other current potential curves N2, P1, P2, and P3 have the same meaning.

Therefore, the conditions regarding VRLA overvoltage (mV) / charging current are as follows.
N2 (VRLA) improved negative electrode overvoltage (mV) / charging current ≦ 10.4
P1 (VRLA) Conventional positive overvoltage (mV) / charging current = 19.6
From FIG. 3, there is theoretically a condition that the conventional positive electrode is used as it is, and the charging current is more than doubled by improving only the negative electrode. That is, in the overvoltage region that the negative electrode can actually take, the relationship between the greatly improved negative electrode satisfying the double charging current shown in FIG. 3 and the overvoltage of the conventional positive electrode can be obtained. The current potential curve of the corresponding negative electrode is very close to the actually measured current potential curve N3 shown in FIG. Conditions satisfying the charging current of 2 times or more are included in the negative electrode and positive electrode overvoltage conditions shown in the necessary condition of (b1), but it is important to confirm in principle whether or not the negative electrode and positive electrode overvoltage conditions exceed twice. There is a meaning. In the present invention, an improved negative electrode satisfying a charging current of twice or more is referred to as a greatly improved negative electrode.

(B2) Improvement of negative electrode: doubling Under conditions of a charging voltage of 2.333 V with respect to a single cell 2V, the conditions for flowing twice the current when using a conventional negative electrode and positive electrode are as follows. A current value that is twice the charging current of the conventional battery shown in FIG. 3 is an overvoltage distribution condition that crosses the current-potential curve of P1 and the negative electrode. From FIG. 3, the overvoltage applied to the positive electrode is 164 mV, and the total overvoltage is constant at 198 mV. Therefore, the negative electrode condition for flowing a current more than twice is (198-164) mV = 34 mV. The negative overvoltage (mV) / charging current (area of about 7 A or less, 0 A or more) of the greatly improved negative electrode, in which the charging current becomes twice or more, overlaps with the relationship of the N3 current potential and becomes the following.
Greatly improved negative electrode overvoltage (mV) / charging current ≦ 2.8
P1 conventional positive electrode overvoltage (mV) / charge current = 17.7
Largely improved negative electrode overvoltage (mV) / charging current (approximately 7 A or less, region of 0 A or more) ≦ 2.8 is given the same gradient as the negative electrode current potential curve negative electrode indicated by the measured N3. Note that the origin of the N3 gradient is X0 where the overvoltage is zero and the charging current is zero.

Therefore, the conditions regarding VRLA overvoltage (mV) / charging current are as follows.
Greatly improved negative electrode (VRLA) overvoltage (mV) / charging current ≦ 3.1
P1 (VRLA) Conventional positive overvoltage (mV) / charging current = 19.6
(C1) Only positive electrode is improved: 1.5 times As long as the conventional negative electrode N1 is used, there is no positive electrode condition of 1.5 times by improving only the positive electrode. This is apparent from FIG. A so-called reversal is required in which the positive overvoltage of the positive electrode enters the negative electrode overvoltage region (minus), and in this case, the function of the lead storage battery is lost.

(D1) Improvement of both negative electrode and positive electrode: 1.75 times The combination giving a charging current of 1.75 times shown in FIG. 3 is (N2 / P2). 1. The gradient for N2 modified negative electrode exceeding 0.75 times (mV / ampere (about 7A or less, 0A or more region)) and the gradient for P2 modified positive electrode (mV / ampere (about 7A or less, about 1A (X1) or more region) )) Is under the following conditions. Note that the origin of the N2 gradient is X0 where the overvoltage is zero and the charging current is zero.
N2 improved negative electrode overvoltage (mV) / charging current ≦ 9.4
P2 improved positive electrode overvoltage (mV) / charging current ≦ 12.4
This fact clearly shows that there is a condition that exceeds twice the charging current shown in FIG. 3 by further reducing the overvoltage of the improved negative electrode N2 and further reducing the overvoltage of the improved positive electrode P2. Conditions exceeding twice are dramatic in improving the charging performance of lead-acid batteries mounted on ISS cars. The improved (N3 / P1) battery and the improved (N3 / P3) battery shown in Table 1 are JIS standard 80D23 type lead produced by combining the negative electrode of N3 and P3 shown in FIG. It is a storage battery. The performance of the obtained battery reproduces the above-mentioned conditions of 1.5 times, 1.75 times and more than 2 times.

Therefore, the conditions regarding the overvoltage (mV) / charge current of YRLA in this condition are as follows.
N2 (VRLA) improved negative electrode overvoltage (mV) / charging current ≦ 10.4
P2 (VRLA) improved positive overvoltage (mV) / charging current ≦ 13.7
The values of overvoltage (mV) / charging current (area of about 7 A or less, about 1 A (X1) or more)) in the measured current potential curves of N3 and P3 are as follows. Note that the origin of the N3 gradient is X0 where the overvoltage is zero and the charging current is zero.
N3 current potential curve slope (mV / Ampere) = 2.8
P3 current potential curve slope (mV / ampere) = 8.9
As is apparent from FIG. 3, the condition of N3 is included in the condition (b1), and the condition of P3 is included in the condition (d1). Each condition of (b1) to (b2) and (c1) and (d1) shown in the relationship between overvoltage and current of the present invention improves the charge acceptance performance necessary for the lead storage battery mounted on the ISS car. It is clear that essential conditions are disclosed.

Therefore, the current potential curves of N3 and P3 are as follows in VRLA.
N3 (VRLA) current potential curve slope (mV / ampere) = 3.1
P3 (VRLA) current-potential curve slope (mV / ampere) = 9.9
<Negative electrode and positive electrode active material conditions>
The electrode plate preparation contents and container formation conditions before charging (unformed) the negative electrode and positive electrode active materials that give N1, N3, P1, and P3 shown in FIG. 3 are shown below. These conditions are the same whether the electrolyte is prepared to have a specific gravity of 1.28 of a liquid lead-acid battery or to the electrolyte specific gravity of 1.32. The electrolyte specific gravity 1.32 of VRLA is a negative electrode and a positive electrode manufactured under initial conditions, and is finally prepared from 1.28 to 1.32. The data in Table 2 was obtained in this way.

  First, the production contents of the unformed negative electrode plate are shown. Kneaded by adding water to a mixture of lead oxide, cut fiber (polyethylene terephthalate short fiber, hereinafter the same), barium sulfate, carbonaceous conductive material, and organic compound that suppresses coarsening of the negative electrode active material, Then, the mixture was kneaded while dilute sulfuric acid was added little by little to prepare a negative electrode active material paste. This active material paste is filled in an expanded current collector (grid) produced by subjecting a rolled sheet made of a lead alloy to an expanding process, and aged for 24 hours in an atmosphere of 40 ° C. and 95% humidity. Then, it was dried to produce an unformed negative electrode plate. In the case of the electrode plate for electrochemical measurement, the expanded current collector (grid body) shown in FIG. 4 was filled.

  Next, the production content of the unchemically formed positive electrode plate is shown. Water was added to a mixture of lead oxide, red lead and cut fiber and kneaded, and then kneaded while adding dilute sulfuric acid little by little to produce an active material paste for positive electrode. This active material paste is filled into an expanded current collector (lattice) produced by subjecting a rolled sheet made of a lead alloy to an expanding process, and aged for 24 hours in an atmosphere of 40 ° C. and a humidity of 95%. It dried and the unchemically formed positive electrode plate was produced. In the case of the electrode plate for electrochemical measurement, the expanded current collector (grid body) shown in FIG. 4 was filled.

  Next, the seven unformed positive electrode plates and the eight unformed negative electrode plates are alternately laminated one by one via a retainer to produce an electrode plate group. The electrode plate group is inserted into the battery case to form a battery case. The retainer is a mat-like electrolyte solution holder mainly composed of short glass fibers and integrated with these. This retainer is commonly used in VRLA.

In the battery case formation, dilute sulfuric acid having a specific gravity of 1.24 was injected into the battery case, and an amount of electricity of 200% of the theoretical capacity based on the amount of active material was passed through to complete a lead storage battery. The same conditions apply for the production of an electrode plate for electrochemical measurement. Conventional negative electrode N1 in the present invention is 0.1% by mass of carbon black, lignin (sodium lignin sulfonate represented by the chemical structural formula of [Chemical Formula 2]) 0 .3% by mass, 1% by mass of barium sulfate, 0.1% by mass of cut fiber were mixed with lead powder (PbO), which is the main raw material of the active material, to make an active material with 15% by mass of lead sulfate before chemical conversion. is there. In the conventional positive electrode P1, 0.026% by mass of sulfate (Na ₂ SO ₄ ) and 0.25% by mass of cut fiber are mixed with lead powder (PbO) which is the main raw material of the active material, and the amount of lead sulfate before conversion is 16 It is a mass% active material. The difference in the active material composition that gives the current-potential curves of N3 and N1 is that the negative electrode active material that gives N1 uses 0.3% by mass of sodium lignin sulfonate represented by the chemical structural formula (partial structure) of [Chemical Formula 2]. N3 is bisphenol A / sodium aminobenzenesulfonate / formaldehyde condensate represented by the chemical structural formula of [Chemical Formula 1] (molecular weight: 10,000 to 40,000, sulfur content in the compound is 6 to 11 mass) %) Is 0.2 mass%. The difference in the active material configuration that gives the current-potential curves of P1 and P3 is that the positive electrode active material that gives P1 has a paste-like active material density of 3.85 g / cm ³ , whereas the positive electrode active material that gives P3 gives The paste-like active material density is 4.45 g / cm ³ . This difference is due to the difference in the content of lead sulfate produced when producing the paste-like active material. Therefore, the active material giving P3 has a filling amount increased by 10% or more compared to the conventional active material giving P1 even when the same volume of active material is applied.

The decrease in the overvoltage of P3 shown in FIG. 3 is considered to be basically due to the increase in the amount of active material. That is, it is considered that the conductive network in the active material becomes dense due to the high-density active material paste that gives P3. It is considered that lead sulfate produced by lowering of the SOC is likely to be finely dispersed with high density. When the conductive network becomes dense and lead sulfate is finely dispersed, the absolute amount of divalent lead ions generated by the dissociation equilibrium of lead sulfate increases, and it is considered that the charging current easily flows due to the effect of the conductive network. When the active material volume per one positive electrode is viewed on the electrode plate of a B-type lead acid battery defined in JIS, it is 15 to 16 cm ³ level. In the case of 15 cm ³ , the filling amount of the conventional active material that gives P1 is 57.7 g. On the other hand, the filling amount of the conventional active material that gives P3 is 66.75 g in the case of 15 cm ³ . If the coating volume of the positive electrode plate of the B-type battery is 15 cm ³ , the filling weight of 66.0 to 67.5 g should use the positive electrode active material having a paste-like active material density of 4.40 to 4.50 g / cm ^3. Can be obtained. Therefore, in order to obtain the P3 current-potential curve, the paste-like active material density is 4.40 to 4.50 g / cm ³ , the moisture content is 11.5 ± 1.0 mass%, and the penetration is 135 ± 40 (10 ^{− 1} mm) of a positive electrode paste-like active material is required, and if the coating volume is 15 cm ³ , the filling weight is 66.0 to 67.5 g. The penetration is measured with a (grease) consistency tester specified in JIS K2220.

The positive electrode active material condition of P2 showing the threshold value of the positive electrode current potential curve satisfying the charge acceptance performance of 1.75 times or more is a paste-like active material density of 3.80 to 4.40 g / cm ³ , and a moisture content of 11 to 14% by mass. The penetration is 135 ± 40 (10 ⁻¹ mm).

  FIG. 5 shows the time transition of the charging current in a liquid lead acid battery having an electrolyte specific gravity of 1.28. The battery is similarly a JIS regulated 80D23 type lead acid battery. The lowest charging current in FIG. 5 is the N1 and P1 configuration (N1 / P1) shown in FIG. 3, that is, the conventional battery. N3 and P1 configuration (N3 / P1) batteries exhibit intermediate charge acceptance currents. It is the N3 and P3 configuration (N3 / P3) batteries that show the maximum charging current. The battery evaluation results are consistent with the conditions for charging current 1.5 times as analyzed in FIG. However, the current-potential curve in FIG. 3 corresponds to the data for the fifth second in FIG.

<Analysis>
The presence of the bisphenol A / sodium aminobenzenesulfonate / formaldehyde condensate shown in [Chemical Formula 1] in the negative electrode active material of the current-potential curve N3 and the improved N3 shown in FIG. 3 is confirmed by nuclear magnetic resonance (Nuclear Magnetic). It was confirmed by Resonance (hereinafter NMR) spectroscopy. Analysis was carried out as follows using an NMR spectrometer (model: ECA-500FT-NMR) manufactured by JEOL Ltd.

  First, the lead storage battery of this example after the chemical conversion was disassembled, the negative electrode plate was taken out, washed with water, and the sulfuric acid content was washed away. The negative electrode active material after chemical conversion is porous metallic lead. In order to prevent oxidation of the negative electrode active material, the negative electrode plate was dried in an inert gas such as nitrogen. The negative electrode active material was separated from the dried negative electrode plate and pulverized, the pulverized product was put into a 10% sodium hydroxide solution, and the extracted liquid from which the generated precipitate (lead hydroxide) was removed was extracted with the above apparatus. Analyzed and measured. The measurement conditions are as shown in Table 3.

  FIG. 6 shows the spectrum measured by NMR spectroscopy. The horizontal axis represents chemical shift (ppm), and the vertical axis represents peak intensity.

  As shown in FIG. 6 with double circles, p-aminobenzene sulfone of bisphenol A / sodium benzenesulfonic acid / formaldehyde condensate shown in [Chemical Formula 1] has chemical shifts of 6.7 ppm and 7.5 ppm. A peak derived from an acid group was observed. Further, as indicated by a triangle in FIG. 6, the bisphenol A skeleton of the bisphenol A / sodium benzenesulfonate / formaldehyde condensate shown in [Chemical Formula 1] in the chemical shift range of 0.5 ppm to 2.5 ppm. A peak derived from was observed.

  From the above results, it was confirmed that the bisphenol A / sodium aminobenzenesulfonate / formaldehyde condensate represented by [Chemical Formula 1] was present in the negative electrode active material.

  As described above, the present invention makes it possible to provide a VRLA with improved charge acceptability and lifetime performance under PSOC, and the spread of micro hybrid vehicles such as ISS vehicles and power generation control vehicles. It contributes to. Therefore, the present invention is useful for solving the global problem of reducing carbon dioxide emission by improving the fuel efficiency of automobiles and suppressing global warming, and has great industrial applicability. .

Claims (10)

A battery case in which a negative electrode plate formed by filling a negative electrode current collector with a negative electrode active material and a positive electrode plate formed by filling a positive electrode active material with a positive electrode current collector through a retainer together with an electrolytic solution It is a control valve type lead acid battery having a configuration housed therein, in which charging is performed intermittently and high rate discharge to the load is performed in a partially charged state,
In a sulfuric acid electrolyte solution having a specific gravity of 1.32 at a temperature of 25 ° C., a negative electrode single plate (area 108 cm ² ) constituting the negative electrode plate and a positive electrode single plate (area 108 cm) constituting the positive electrode plate facing the negative electrode single plate. ² ) comprises an electrochemical measurement system in which a reference electrode serving as a potential reference is installed between the negative electrode single plate and the positive electrode single plate, and the negative electrode single plate and the positive electrode single plate The control valve-type lead-acid battery was charged at a charging voltage of 2.33 V, and the relationship between the negative charge overvoltage and the positive charge overvoltage applied at the time of 5 seconds from the start of charging and the corresponding charging current was plotted. Using the current-potential curve,
In the region obtained by plotting the point where the absolute value of the charge overvoltage starts to increase from 0 (zero) as an origin, approximating a straight line from the origin,
| [Negative electrode overvoltage (mV) / Charge current (Ampere)] | Negative electrode plate comprising a negative electrode active material that satisfies 10.4.
[Positive electrode charge overvoltage (mV) / Charge current (ampere)] ≦ 19.6, comprising a positive electrode plate comprising a positive electrode active material ,
The positive electrode active material, a valve-regulated lead-acid battery, characterized in der Rukoto those configured using the positive electrode paste active material prepared in density 4.4~4.5g / cm ^3.   As an organic compound in which the negative electrode active material suppresses the coarsening of the negative electrode active material due to charge / discharge, an organic compound mainly composed of bisphenols / aminobenzenesulfonic acid / formaldehyde condensate, graphite, carbon black, activated carbon, 2. The control valve-type lead-acid battery according to claim 1, comprising at least one carbonaceous conductive material selected from a material group consisting of carbon fibers and carbon nanotubes. The control valve-type lead-acid battery according to claim 2, wherein the bisphenol / aminobenzenesulfonic acid / formaldehyde condensate is represented by the following chemical structural formula:
  2. The valve-regulated lead-acid battery according to claim 1, wherein the positive electrode active material is a positive electrode active material satisfying [positive electrode charge overvoltage (mV) / charge current (ampere)] ≦ 13.7. The positive electrode active material, water content 11 to 14 wt%, a valve-regulated lead-acid battery of claim 4, wherein those constructed using the positive electrode paste active material prepared in penetration from 95 to 175. The negative electrode active material is a negative electrode active material satisfying | [negative electrode charge overvoltage (mV) / charge current (ampere)] | ≦ 3.1,
2. The valve-regulated lead-acid battery according to claim 1, wherein the positive electrode active material is a positive electrode active material satisfying [positive electrode charge overvoltage (mV) / charge current (ampere)] ≦ 19.6.   The negative electrode active material is mainly composed of bisphenols / sodium aminobenzenesulfonate / formaldehyde condensate represented by the chemical structural formula of [Chemical Formula 1] as an organic compound that suppresses the coarsening of the negative electrode active material accompanying charge / discharge. The control valve-type lead-acid battery according to claim 6, which contains an organic compound and scaly graphite as a carbonaceous conductive material.   The control valve-type lead acid battery according to claim 7, wherein an average primary particle diameter of the flake graphite is 100 µm or more.   The negative electrode active material is a negative electrode active material satisfying | [negative electrode charge overvoltage (mV) / charge current (ampere)] | ≦ 3.1, and the positive electrode active material is [positive electrode charge overvoltage (mV) / charge current]. The control valve-type lead-acid battery according to claim 1, wherein the positive-electrode active material satisfies (ampere)] ≤9.9. As the organic compound that suppresses the coarsening of the negative electrode active material due to charge and discharge, the negative electrode active material is mainly composed of a bisphenol, sodium aminobenzenesulfonate, and formaldehyde condensate represented by the chemical structural formula of [Chemical Formula 1]. An organic compound to be used, and a scale-like graphite having an average primary particle size of 100 μm or more as a carbonaceous conductive material,
The positive electrode active material, water content 10.5 to 12.5% by weight, valve-regulated according to claim 9, wherein those constructed using the positive electrode paste active material prepared in penetration from 95 to 175 Lead acid battery.