JP6965892B2 - Liquid lead-acid battery, charging / discharging method of liquid lead-acid battery, and power supply system - Google Patents

Description

The present invention relates to a liquid lead-acid battery, a charging / discharging method for the liquid lead-acid battery, and a power supply system.

Lead-acid batteries are widely used in industry, for example, in automobile batteries, backup power supplies, and main power supplies for electric vehicles. In recent years, automobiles have adopted an idling stop and start system (hereinafter referred to as "ISS") that stops the engine when controlling power generation, waiting for a signal, etc., for the purpose of carbon dioxide emission regulation measures, fuel efficiency, etc. It has become so.

Since the alternator does not generate electricity during the idling stop, all the electric power to the electric equipment is supplied from the lead-acid battery, and the lead-acid battery discharges deeper than before. In addition, since the alternator's power generation is controlled even during driving, the battery becomes insufficiently charged.

When deep discharge and insufficient charging are repeated in a lead-acid battery, stratification of the electrolytic solution has become apparent as a factor for shortening the life of the lead-acid battery. Here, the stratification by repeated charge and discharge, sulfate ions in the electrolyte (SO 4 ^_2-) and hydrogen sulfate ion (HSO 4 _-) ^{(hereinafter,} these are collectively referred to as "sulfate ions") sedimentation Then, it refers to a phenomenon in which the specific gravity of the electrolytic solution differs between the upper and lower parts of the battery case. This stratification becomes more remarkable as the ratio of the remaining capacity to the fully charged capacity of the lead-acid battery (hereinafter, also simply referred to as “remaining capacity”) becomes smaller. Therefore, it is an important issue to suppress stratification in lead-acid batteries for ISS vehicles used in an intermediate charge state where it is difficult to obtain the stirring effect of the electrolytic solution, and in particular, the remaining capacity is as in the lead-acid batteries for ISS vehicles for Europe. When used under small conditions, more advanced stratification suppression technology is required.

In response to such problems, Patent Document 1 states that liquid lead can ensure liquid retention and extend the life of lead-acid batteries by forming a porous resin layer containing butyl rubber or the like on the electrode surface. The storage battery is listed.

Japanese Unexamined Patent Publication No. 2003-223890

However, the lead-acid battery as described in Patent Document 1 still has room for improvement in terms of suppressing the stratification of the electrolytic solution, especially when it is used under the condition that the remaining capacity is small.

Therefore, an object of the present invention is to suppress stratification of an electrolytic solution and improve the life of a liquid lead-acid battery used with a predetermined remaining capacity.

According to the study by the present inventors, the effect of stratification is small in the vicinity of the positive electrode because the water generated during discharge promotes the mixing of the electrolytic solution, but there is no such effect in the vicinity of the negative electrode. Stratification is likely to occur. Further, stratification occurs more remarkably as the remaining capacity of the lead-acid battery is smaller. Therefore, as a result of further studies, the present inventors have put a film body having pores having an average pore diameter of 15 μm or less between the negative electrode and the separator in a liquid lead-acid battery used with a predetermined remaining capacity. It has been found that the stratification of the electrolytic solution can be suppressed and the durability can be improved when the electrolytic solution is provided in the above.

That is, in one embodiment, the present invention comprises a positive electrode plate, a negative electrode plate, a separator arranged between the positive electrode plate and the negative electrode plate, a film body arranged between the negative electrode plate and the separator, and an electrolytic solution. A positive electrode plate, a negative electrode plate, a separator, a film body, and an electric tank for accommodating an electrolytic solution, and the film body has pores having an average pore diameter of 15 μm or less, and the ratio of the remaining capacity to the full charge capacity. It is a liquid lead-acid battery used so that the value is 90% or less.

In one aspect, the film body comprises a non-woven fabric containing inorganic fibers or a non-woven fabric containing organic fibers and inorganic fibers.

In one aspect, the separator is a bag-shaped separator, and the negative electrode plate and the film body are housed in the separator.

In one embodiment, the membrane has a thickness of 0.3 mm or less, a porosity of 20% or more and 30 g / m. ²~ 50g / m²It has a basis weight of.

In another aspect, the present invention is a method for charging / discharging a liquid lead-acid battery, which charges / discharges the liquid lead-acid battery so that the ratio of the remaining capacity to the full charge capacity is 90% or less.

In another aspect, the present invention includes the above-mentioned liquid lead-acid battery and a control unit that controls charging / discharging of the liquid lead-acid battery, and the control unit is the remaining capacity with respect to the full charge capacity of the liquid lead-acid battery. It is a power supply system that controls charge / discharge so that the ratio of the above is 90% or less.

According to the present invention, in a liquid lead-acid battery used with a predetermined remaining capacity, stratification of an electrolytic solution can be suppressed and the life can be improved.

It is a perspective view which shows the whole structure and the internal structure of the lead storage battery which concerns on one Embodiment. It is a perspective view which shows the electrode group of the lead storage battery which concerns on one Embodiment. It is a schematic cross-sectional view which shows the cross section seen by the arrow along the line I-I in FIG. It is a figure which shows the component of the alternator regenerative vehicle which concerns on one Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

FIG. 1 is a perspective view showing the overall configuration and internal structure of the liquid lead-acid battery (hereinafter, also simply referred to as “lead-acid battery”) according to the embodiment. As shown in FIG. 1, the lead-acid battery 1 according to the present embodiment includes an electric tank 2 having an open upper surface and a lid 3 for closing the opening of the electric tank 2. The battery case 2 and the lid 3 are made of polypropylene, for example. The lid 3 is provided with a negative electrode terminal 4, a positive electrode terminal 5, and a liquid port plug 6 for closing the liquid injection port provided in the lid 3.

Inside the battery case 2, an electrode group 7, a negative electrode column 8 connecting the electrode group 7 to the negative electrode terminal 4, a positive electrode column (not shown) connecting the electrode group 7 to the positive electrode terminal 5, dilute sulfuric acid, etc. Electrolyte and is stored.

In one embodiment, the lead-acid battery 1 may have a width dimension of D or more in the category specified in JIS D5301. The width dimension of the lead storage battery 1 may be, for example, D, E, F, G or H in the classification defined in JIS D5301.

In one embodiment, the lead-acid battery 1 may have a width dimension of LBN0 or more or LN0 or more in the category specified in EN 50342-2. The width dimension of the lead-acid battery 1 may be, for example, LBN0 to 6 or LN0 to 6 in the classification specified in EN 50342-2.

The lead-acid battery 1 may have a width dimension of 170 mm or more in one embodiment. The width dimension of the lead storage battery 1 may be, for example, 175 mm or more or 180 mm or more, or 280 mm or less or 225 mm or less.

FIG. 2 is a perspective view showing the electrode group 7. As shown in FIG. 2, the electrode group 7 includes a plate-shaped negative electrode plate 9 containing metal lead (Pb) as an active material, a plate-shaped positive electrode _{plate 10 containing lead dioxide (PbO 2} ) as an active material, and a negative electrode. A separator 11 arranged between the plate 9 and the positive electrode plate 10 is provided. The electrode group 7 has a structure in which a plurality of negative electrode plates 9 and positive electrode plates 10 are alternately laminated in a direction substantially parallel to the opening surface of the battery case 2 via a separator 11. That is, the negative electrode plate 9 and the positive electrode plate 10 are arranged so that their main surfaces extend in the direction perpendicular to the opening surface of the battery case 2.

The ears 9a of the plurality of negative electrode plates 9 are collectively welded by the negative electrode side strap 12. Similarly, the ears 10a of the plurality of positive electrode plates 10 are collectively welded by the positive electrode side strap 13. Then, the negative electrode side strap 12 and the positive electrode side strap 13 are connected to the negative electrode terminal 4 and the positive electrode terminal 5 via the negative electrode column 8 and the positive electrode column, respectively.

FIG. 3 is a schematic cross-sectional view showing a cross section seen along the line I-I in FIG. As shown in FIG. 3, a film body 14 is provided between the negative electrode plate 9 and the separator 11.

The separator 11 is formed in a bag shape, for example, and the negative electrode plate 9 and the film body 14 are housed in the separator 11. Examples of the material forming the separator 11 include polyethylene (PE), polypropylene (PP) and the like. The separator 11 may be one in which inorganic particles _{such as SiO 2} and Al ₂ O ₃ are attached to a woven fabric, a non-woven fabric, a porous film or the like formed of these materials.

The thickness of the separator 11 is preferably 0.1 mm to 0.5 mm, more preferably 0.2 mm to 0.3 mm. When the thickness of the separator 11 is 0.1 mm or more, the strength of the separator can be ensured. When the thickness of the separator 11 is 0.5 mm or less, an increase in the internal resistance of the battery can be suppressed.

The average pore size of the separator 11 is preferably 10 nm to 500 nm, more preferably 30 nm to 200 nm. When the average pore size of the separator 11 is 10 nm or more, sulfate ions can be suitably passed through and the diffusion rate of sulfate ions can be ensured. When the average pore diameter of the separator 11 is 500 nm or less, the growth of lead dendrites is suppressed and short circuits are less likely to occur.

In the present embodiment, the film body 14 is provided in close contact with the negative electrode plate 9 so as to cover the surface of the negative electrode plate 9. The film body 14 may be in the form of a sheet or a bag, for example. When the film body 14 is in the form of a sheet, the film body 14 covers the surface of the negative electrode plate 9 so as to be wound around the negative electrode plate 9. When the film body 14 has a bag shape, the negative electrode plate 9 is housed in the film body 14.

The film body 14 includes, for example, a non-woven fabric, preferably a non-woven fabric containing inorganic fibers. The non-woven fabric containing the inorganic fiber may be an inorganic non-woven fabric containing only the inorganic fiber as the fiber, or an organic / inorganic mixed non-woven fabric containing the organic fiber and the inorganic fiber as the fiber. Examples of the inorganic fiber include SiO ₂ fiber (glass fiber). Examples of the organic fiber include synthetic fibers such as polyethylene, polypropylene, polyester, nylon and aramid. The organic / inorganic mixed nonwoven fabric may further contain an inorganic powder formed of _{SiO 2 or the like.}

In the film body 14 having pores as described above, the average pore diameter is 15 μm or less from the viewpoint of suppressing the stratification of the electrolytic solution. The average pore diameter of the film body 14 is preferably 14 μm or less, 13 μm or less, 12 μm or less, 11 μm or less, or 10 μm or less from the viewpoint of further suppressing the stratification of the electrolytic solution. The average pore diameter of the film body 14 is preferably 0.1 μm or more, 1 μm or more, 2 μm or more, or 3 μm from the viewpoint of improving the output of the battery.

The average pore diameter of the film body is X corresponding to the median value between the minimum value and the maximum value on the Y axis (pore volume or pore specific surface area) of the distribution curve in the integrated pore diameter distribution measured by the mercury intrusion method. It is calculated as the median diameter, which is the value of the axis (pore diameter). The average pore size of the membrane can be measured by, for example, Autopore IV 9500 manufactured by Shimadzu Corporation.

By providing the film body 14 as described above between the negative electrode plate 9 and the separator 11, the accumulation of sulfate ions in the lower part of the electric tank 2 can be suppressed, and the stratification of the electrolytic solution can be suppressed. In other words, by providing the membrane body 14, the concentration of sulfate ions inside the battery case 2 can be kept uniform, and the uneven distribution of the battery reaction can be suppressed, so that the life of the lead storage battery 1 can be improved. Become. By providing such a film body 14 in the vicinity of the negative electrode plate 9 separately from the separator 11, for example, higher stratification can be achieved as compared with the case where the separator 11 is subjected to a treatment for suppressing stratification. A suppressive effect can be obtained.

The present inventors consider the reason why the stratification of the electrolytic solution is suppressed by providing the film body 14 as follows. That is, the aggregate of sulfate ions generated in the charging reaction collides with the pores of the membrane body 14, becomes high-concentration particles while diffusing, and slowly precipitates in the electrolytic solution. When the membrane body 14 having a specific average pore diameter is provided, the sedimentation rate of sulfate ions is reduced as compared with the case where the membrane body 14 is not provided, so that stratification can be suppressed. When the remaining capacity of the lead-acid battery 1 is small, the amount of sulfate ions is particularly large, and this tendency is remarkable.

When charging with a large current as in ISS vehicle applications, a large amount of sulfate ions are released from the electrode plate, so the higher the sulfate ion retention capacity of the membrane body 14, the more preferable. When the film body 14 includes a non-woven fabric, the fiber diameter of the fibers constituting the non-woven fabric is preferably 10 μm or less, more preferably 5 μm or less. When the fiber diameter is 10 μm or less, the specific surface area of the membrane body 14 becomes large and the space for holding sulfate ions can be increased, so that the sulfate ion holding capacity of the membrane body 14 can be further improved. can. The fiber diameter is preferably 1 μm or more from the viewpoint of suppressing fiber breakage, tearing of the film body, and ensuring durability.

The thickness of the film body 14 is preferably 0.3 mm or less, more preferably 0.25 mm or less, still more preferably 0.2 mm or less, and particularly preferably 0.15 mm or less, from the viewpoint of suppressing an increase in internal resistance. .. The thickness of the membrane body 14 is, for example, 0.03 mm or more from the viewpoint of the ability to prevent the precipitation of sulfate ions, the influence on the battery reaction, the strength, and the like. When the film body 14 includes the non-woven fabric, the thickness of the film body 14 is determined according to the thickness of the fibers constituting the non-woven fabric and the like.

The porosity of the membrane body 14 is preferably 20% or more, more preferably 40% or more, still more preferably 60% or more, from the viewpoint of ensuring the diffusibility of sulfate ions and increasing the space for retaining sulfate ions. , Especially preferably 80% or more. The porosity of the membrane body 14 may be, for example, 95% or less. The porosity of the membrane body is calculated from the actual volume and the apparent volume of a sample cut into a rectangular parallelepiped shape of an appropriate size from the membrane body according to the following formulas (1) to (3).
Porosity (%) = {1- (actual volume / apparent volume)} x 100 ... (1)
Actual volume (cm ³ ) = measured weight (g) / density (g / cm ³ ) ... (2)
Apparent volume (cm ³ ) = length (cm) x width (cm) x thickness (cm) ... (3)
The measured values are used for the length, width, and thickness of the sample when calculating the apparent volume.

Basis weight of the film body 14, from the viewpoint of compatibility between the suppression of stratification suppressing the internal resistance increase, preferably ^{30g / m 2 ~50g / m 2} , more preferably ^{35g / m 2 ~50g / m 2} , more preferably is a ^{40g / m 2 ~50g / m 2} . The basis weight is calculated as the mass per unit area of the film body 14.

In the above embodiment, the film body 14 covers all of the main surface (the surface facing the separator 11), the side surface, and the bottom surface of the negative electrode plate 9 and is provided so as to be in contact with the surfaces thereof (in close contact with each other). However, in another embodiment, the film body may be provided between the negative electrode plate 9 and the separator 11 so as to be separated from the negative electrode plate 9. In this case, the film body 14 may be provided, for example, on the surface of the separator 11 on the negative electrode side. From the viewpoint of further suppressing the stratification of the electrolytic solution, it is preferable that the film body 14 is provided so as to be in contact with (in close contact with) the surface of the negative electrode plate 9.

In the above embodiment, the film body 14 covers all of the main surface (the surface facing the separator 11), the side surface and the bottom surface of the negative electrode plate 9, but in other embodiments, the film body is the main surface of the negative electrode plate 9. It may be provided so as to cover only the surface (the surface facing the separator 11).

The lead-acid battery described above is used so that the ratio of the remaining capacity to the fully charged capacity (remaining capacity / fully charged capacity) is 90% or less. The ratio (remaining capacity / fully charged capacity) may be 85% or less or 80% or less, and may be 50% or more, 55% or more, or 60% or more. The lead-acid battery does not need to be used so that the ratio of the remaining capacity to the full charge capacity is constantly within the above range, and is at least temporarily (that is, the minimum value of the ratio of the remaining capacity to the full charge capacity). However, it may be used so as to be within the above range.

Next, an embodiment of a power supply system including the above-mentioned liquid lead-acid battery will be described. In one embodiment, the power supply system is mounted in the engine room of an alternator regenerative vehicle (μHEV). However, the present invention is not limited to this embodiment. The μHEV refers to a gasoline vehicle or a diesel vehicle having an ISS function, capable of accepting regenerative power supplied from an alternator, and equipped with a power storage device capable of discharging to a discharge load.

FIG. 4 is a diagram showing components of an alternator regenerative vehicle according to an embodiment. As shown in FIG. 4, the alternator regenerative vehicle 21 includes a vehicle control unit (ECU) 22, an alternator 23, a discharge load 24, and a power supply system 25.

The vehicle control unit 22 controls the operation of the entire alternator regenerative vehicle 21. The vehicle control unit 22 grasps whether the ignition switch is located at the OFF position, the ON / ACC position, or the START position, and determines the operating state of the accelerator, brake, engine, etc., and the vehicle state such as speed and acceleration. Grasp and perform running control according to the grasped state.

The vehicle control unit 22 can communicate with the control unit of the power supply system 25 (details will be described later), receives information on the state of the lead-acid batteries constituting the power supply system 25, and informs the control unit of the power supply system 25. It transmits vehicle status information (ignition switch position information, alternator operation information, etc.).

The alternator 23 is controlled by the vehicle control unit 22, and converts the rotational force of the engine into (regenerative) electric power when the alternator regenerative vehicle 21 is braking, the accelerator is off, or the like. The alternator 23 includes a power generation unit composed of a stator and a rotor, a rectifying unit that converts AC power generated by the power generation unit into DC power, and a voltage for keeping the voltage of the DC power converted by the rectifying unit constant. It is equipped with a regulator. The output voltage of the alternator 23 is set to, for example, 14V.

The discharge load 24 includes a starter (starter motor) and auxiliary equipment. Examples of auxiliary machines include lamps (lights), engine pumps (spark plugs), air conditioners, fans, radios, televisions, CD players, car navigation systems, and the like. A minimum voltage (for example, 8V) for operating is supplied to the auxiliary machine from the power supply system 25 (lead-acid battery 1). Further, when the engine of the alternator regenerative vehicle 21 is started, the ignition switch is set to the START position, power is supplied from the power supply system 25 (lead storage battery 1) to the starter, the starter rotates, and the starter rotates on the rotating shaft of the engine via the clutch mechanism. The rotational driving force of the engine is transmitted and the engine starts.

The power supply system 25 includes the lead-acid battery 1, the selector 26, the battery controller 27, the current sensor 28, and the control unit 29 described above, and constitutes, for example, a 14V system power supply system. The lead-acid battery 1 can accept the regenerative power supplied from the alternator 23 and can discharge to the discharge load 24.

The selector 26 supplies the regenerated electric power from the alternator 23 to the lead-acid battery 1, and discharges the electric power from the lead-acid battery 1 to the discharge load 24. When the power supply system 25 further includes a second storage battery (not shown) other than the lead storage battery 1, the selector 26 receives the regenerative power supplied from the alternator 23 by the power storage device, and the lead storage battery from the alternator 23. It acts as a switch that connects to either the 1st and 2nd storage batteries, and connects to the discharge load 24 from either the lead-acid battery 1 or the 2nd storage battery when discharging from the power storage device to the discharge load 24. Acts as a switch to

The battery controller 27 detects the battery state such as the temperature, voltage, and current of the lead-acid battery 1 during charging / discharging (during vehicle traveling and before vehicle traveling). Specifically, a temperature sensor attached to the lead-acid battery 1 is connected to the battery controller 27, and the battery controller 27 samples the voltage of the temperature sensor at predetermined time (for example, 10 ms) and converts the sampling result into a RAM. Store. The battery controller 27 is connected to the positive electrode terminal and the negative electrode terminal of the lead storage battery 1 and detects the voltage of the lead storage battery 1. A current sensor 28 such as a hall element and a shunt resistor is arranged between the selector 26 and the positive terminal of the lead-acid battery 1, and the battery controller 27 allows the current flowing through the lead-acid battery 1 to flow through the current sensor 28 for a predetermined time ( For example, sampling is performed every 2 ms), and the sampling result is stored in the RAM. Further, the battery controller 27 detects the open circuit voltage and temperature of the lead storage battery 1 when charging / discharging is suspended (when the vehicle is parked).

The battery controller 27 is connected to the control unit 29, transmits information on the temperature, voltage, and current of the lead-acid battery 1 stored in the RAM to the control unit 29 during charging / discharging, and transmits the information regarding the temperature, voltage, and current of the lead-acid battery 1 stored in the RAM to the control unit 29. Information on the open circuit voltage and temperature is transmitted to the control unit 29.

The control unit 29 is configured as a microprocessor including a microcontroller, a communication IC, an I / O, an input port, an output port, and the like. In FIG. 4, details are detailed for each function in order to clarify the role of the control unit 29. Represents.

The microcontroller acts as a work area for a CPU that grasps (calculates) the battery state of the lead-acid battery 1, a basic control program, a ROM that stores program data such as a table, and a CPU, and temporarily stores various data. It consists of a RAM and an internal bus that connects them. The internal bus is connected to the external bus, and the external bus is connected to the battery controller 27 via the input port. An output port for outputting a signal to the selector 26, an I / O, and a communication IC for communicating with the vehicle control unit 22 are connected to the external bus.

Therefore, the microcontroller and input port of the control unit 29 are in the state grasping unit 30 of FIG. 4, the microcontroller and output port are in the selector control unit of FIG. 4, and the communication IC and I / O are in the communication unit 6C of FIG. handle.

The state grasping unit 30 temporarily stores the detection data transmitted from the battery controller 27 in the RAM of the microcontroller, and calculates (estimates) the battery state and the like of the lead storage battery 1. The selector control unit 31 controls the selector 26 according to the operation information of the alternator 23 received from the vehicle control unit 22 and the battery state of the lead storage battery 1 calculated by the state grasping unit 30. The communication unit 32 transmits the battery state of the lead-acid battery 1 calculated by the state grasping unit 30 to the vehicle control unit 22 at predetermined time (for example, 2 ms), and the vehicle control unit 22 transmits the vehicle state information (ignition switch position). Information, operation information of the alternator 23) is received.

The control unit 29 controls the charge / discharge of the lead storage battery 1 so that the ratio of the remaining capacity to the full charge capacity (remaining capacity / full charge capacity) of the lead storage battery 1 is 90% or less. The control unit 29 may control the charge / discharge of the lead-acid battery 1 so that the ratio (remaining capacity / fully charged capacity) is 85% or less or 80% or less, and may be 50% or more, 55% or more, or 60. The charge / discharge of the lead storage battery 1 may be controlled so as to be% or more. The control unit 29 does not need to control so that the ratio of the remaining capacity of the lead-acid battery 1 to the full charge capacity is constantly within the above range, and at least temporarily (that is, the remaining capacity with respect to the full charge capacity). The minimum value of the ratio of) may be controlled to be within the above range. As described above, one embodiment of the present invention can be said to be a charging / discharging method for the lead-acid battery 1 in which the lead-acid battery 1 is charged / discharged so that the ratio of the remaining capacity to the full charge capacity is within the above range.

<Example 1>
A paste-type plate was used in which a lead alloy lattice was filled with a paste prepared by kneading lead powder containing lead monoxide as a main component with dilute sulfuric acid. After that, an unmodified electrode plate was obtained through aging and drying steps. Incidentally, the positive electrode plate and the negative electrode plate which was not chemically converted is composed both divalent lead monoxide is lead compound (PbO), a mixture of such tribasic dilute lead sulfate _{(3PbO · PbSO 4 · H 2} O) ing. By chemical conversion, the unmodified substance of _{the positive electrode plate is oxidized to lead dioxide (PbO 2} ), and the unmodified substance of the negative electrode plate is reduced to spongy lead (Pb) to obtain an existing electrode plate (positive electrode plate, negative electrode plate). Was done.

An inorganic non-woven fabric (main component: SiO ₂ ) as shown in Table 1 was used as the film body and arranged on the negative electrode plate. As the separator, a bag-shaped polyethylene separator having a thickness of 0.25 mm and an average pore diameter of 30 nm to 200 nm was used, and the negative electrode plate and the film body were housed in the separator. Dilute sulfuric acid is used as the electrolytic solution, and D size (JIS D5301. Width: 173 mm, box height: 204 mm. Negative electrode plate width: 145 mm, negative electrode plate height (including upper frame)) that is difficult to suppress stratification. : 113 mm.) A lead-acid battery with a rated capacity of 60 Ah was produced.

(Calculation of average pore diameter)
The average pore size of the membrane was measured with Autopore IV 9500 manufactured by Shimadzu Corporation. The average pore diameter of the film body is X corresponding to the median value between the minimum value and the maximum value on the Y axis (pore volume or pore specific surface area) of the distribution curve in the integrated pore diameter distribution measured by the mercury intrusion method. It was calculated as the median diameter, which is the value of the shaft (pore diameter).

(Evaluation of internal resistance)
The internal resistance of the lead-acid battery, which had been initially charged in advance, was evaluated using a 1 kHz AC mΩ meter. The specific evaluation criteria are shown by the value of the internal resistance when the internal resistance of the lead storage battery is 100 when the film body is not provided (Comparative Example 1). The value of the internal resistance is preferably less than 125, more preferably less than 120, and even more preferably less than 110. The results are shown in Table 1.

(Life test (durability))
In Example 1, the life performance of the lead-acid battery when used so that the ratio of the remaining capacity to the fully charged capacity was 50% was measured as follows. First, a fully charged lead-acid battery that has been fully charged was placed in a water tank in which the bath temperature was set to 40 ± 2 ° C. Next, the following cycle units (a) and (b) were repeated in order. In a 60 Ah lead-acid battery, the 20-hour rate current is 3 A. In addition, this test is a cycle test simulating how the lead-acid battery is used in the ISS vehicle, and it is judged that the life of the lead-acid battery has reached the end when the voltage of the lead-acid battery falls below 10.0V. The results are shown in Table 1.
(A) Discharge for 2 hours at 15A (equivalent to 5 times the 20-hour rate current).
(B) Charge for 5 hours up to 15A (equivalent to 5 times the 20-hour rate current). The upper limit voltage for charging at that time was 15.6 ± 0.1V.

(Evaluation of stratification suppression effect)
The effect of suppressing the stratification of the electrolytic solution was evaluated. Charging and discharging were repeated in the same manner as in the life test, and the difference in the vertical specific density of the electrolytic solution between the upper part and the lower part in the electric tank at the 20th cycle was used as an index of stratification. Specifically, the region from the upper end of the electrode group (upper end of the separator) to 1 cm above was defined as the upper part of the battery case, and the region from the lower end of the electrode group to 1 cm below was defined as the lower part of the battery case. The height of the electrode group (the length from the lower end of the electrode group to the upper end of the separator) was 116 mm. Then, the vertical specific density difference was calculated with the vertical specific density difference of the case where the film body was not provided (Comparative Example 1) as 100. The difference in relative density between the top and bottom is preferably less than 70, and more preferably less than 50. When the difference between the upper and lower specific densities was less than 70, it was judged that stratification was suppressed.

<Examples 2 to 5>
In the life test and the evaluation of the stratification suppressing effect, a lead storage battery was prepared and evaluated in the same manner as in Example 1 except that the ratio of the remaining capacity to the fully charged capacity was changed as shown in Table 1.

<Examples 6 and 7>
A lead-acid battery was prepared and evaluated in the same manner as in Example 1 except that the inorganic non-woven fabric as shown in Table 1 was used as the film body.

<Examples 8 and 9>
As the film body, the same as in Examples 3 and 4, except that an organic / inorganic mixed non-woven fabric (porous sheet. Non-woven fabric composed of mixed fibers containing pulp, glass fiber and silica powder) was used instead of the inorganic non-woven fabric. The lead storage battery was prepared and evaluated.

<Example 10>
The size of the lead-acid battery is LN1 size, which is common in Europe (EN 50342-2. Width: 175 mm, box height: 190 mm. Negative electrode plate width: 143 mm, negative electrode plate height (including upper frame): 100 mm.) A lead-acid battery was prepared and evaluated in the same manner as in Example 4 except that the lead-acid battery was changed to.

<Comparative example 1>
A lead-acid battery was produced and evaluated in the same manner as in Example 1 except that the film body was not provided on the negative electrode plate.

<Comparative example 2>
A lead-acid battery was produced and evaluated in the same manner as in Example 1 except that the film body was not provided on the negative electrode plate and the positive electrode plate was housed in the separator instead of the negative electrode plate.

<Comparative example 3>
A lead-acid battery was produced in the same manner as in Example 1 except that the film body was provided on the positive electrode plate without providing the film body on the negative electrode plate, and the positive electrode plate and the film body were housed in the separator instead of the negative electrode plate. And evaluation was performed.

<Comparative example 4>
A lead-acid battery was prepared and evaluated in the same manner as in Example 4 except that the inorganic non-woven fabric as shown in Table 1 was used as the film body.

<Reference Examples 1 and 2>
In the life test and the evaluation of the stratification suppressing effect, the lead-acid batteries were prepared and evaluated in the same manner as in Example 4 and Comparative Example 4, except that the ratio of the remaining capacity to the fully charged capacity was changed as shown in Table 1. went.

From the above results, in the lead-acid battery used so that the ratio of the remaining capacity to the full charge capacity is 90% or less, stratification is suppressed in the example in which the film body is provided between the negative electrode and the separator. On the other hand, it was found that stratification was not suppressed in Comparative Examples 1 and 2 in which the film body was not provided and in Comparative Example 3 in which the film body was provided between the positive electrode and the separator. On the other hand, in the lead-acid batteries (Reference Examples 1 and 2) used so that the ratio of the remaining capacity to the full charge capacity exceeds 90%, there was no difference in the degree of suppression of stratification depending on the average pore size of the film body. ..

The present invention is not limited to the above examples, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to the embodiment including all the described configurations.

1 ... Lead-acid battery, 2 ... Electric tank, 9 ... Negative electrode plate, 10 ... Positive electrode plate, 11 ... Separator, 14 ... Membrane body, 25 ... Power supply system, 29 ... Control unit.

Claims (5)

With the positive electrode plate
With the negative electrode plate
A separator arranged between the positive electrode plate and the negative electrode plate,
A film body arranged between the negative electrode plate and the separator,
With electrolyte
A positive electrode plate, a negative electrode plate, a separator, a film body, and an electric tank for accommodating the electrolytic solution are provided.
The film body is an inorganic non-woven fabric having pores having an average pore diameter of 15 μm or less and containing only inorganic fibers as fibers.
A liquid lead-acid battery used so that the ratio of the remaining capacity to the fully charged capacity is 90% or less. The liquid lead-acid battery according to claim 1, wherein the separator is a bag-shaped separator, and the negative electrode plate and the film body are housed in the separator. The film body, 0.3 mm or less thick, has more than 20% porosity and ^30g / ^{m 2 ~50g} / m 2 basis weight, a liquid type lead-acid battery according to claim 1 or 2. A method for charging / discharging a liquid lead-acid battery according to any one of claims 1 to 3 , wherein the liquid lead-acid battery is charged / discharged so that the ratio of the remaining capacity to the full charge capacity is 90% or less. The liquid lead-acid battery according to any one of claims 1 to 3 and
A control unit that controls charging / discharging of the liquid lead-acid battery is provided.
The control unit is a power supply system that controls charge / discharge so that the ratio of the remaining capacity to the full charge capacity of the liquid lead-acid battery is 90% or less.

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