JP6597995B2 - Control valve type lead acid battery manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a control valve type lead-acid battery, and more particularly to manufacturing a paste-type electrode plate produced by filling a lattice substrate with an active material.

Lead acid batteries are secondary batteries excellent in cost, safety and reliability, and are used in various applications.
In recent years, in order to protect the global environment and suppress global warming, attempts to reduce carbon dioxide emissions have been regarded as important in various industries.

For example, in the automobile industry, when the vehicle is stopped due to traffic signals or railroad crossings, the engine is stopped once, and the engine is restarted when the accelerator is depressed to start.・ Some models have an AND-START system.
We are also considering the use of natural energy such as solar power generation and wind power generation, temporarily storing the generated energy in lead-acid batteries, and suppressing fluctuations in the generation of natural energy to supply commercial power. It has been broken.

When a lead-acid battery is operated in such a cycle application, the deterioration of the positive electrode active material proceeds, and the active material softening called mudification reduces the bonding force between the active materials, gradually losing the discharge performance and increasing the discharge capacity. The lead-acid battery has a reduced life.
In view of this, a positive electrode active material for cycle use has a method in which the active material density is increased and an active material with improved durability is used to prevent the positive electrode active material from becoming muddy.

Japanese Unexamined Patent Application Publication No. 2007-157613 (Patent Document 1) discloses that the packing density of the positive electrode active material is increased to obtain excellent cycle life characteristics. Japanese Patent Application Laid-Open No. 2005-216741 (Patent Document 2) discloses that a sealed lead-acid battery having excellent cycle life characteristics can be obtained by increasing the density of the positive electrode active material to suppress softening and dropping of the active material. ing.
In JP-A-2002-75433 (Patent Document 3), a grid substrate is filled with an active material paste, and a separator made of a nonwoven fabric is bonded to an undried electrode plate to prevent the active material from falling off and A battery that prevents the displacement of the separator is disclosed.

JP 2007-157613 A JP-A-2005-216741 JP 2002-75433 A

  However, the techniques described in Patent Documents 1 and 2 require increasing the density of the active material paste filled into the lattice substrate, that is, using a hard active material paste. A hard active material paste has a poor filling property to the lattice substrate.In particular, when the active material paste is filled into the lattice substrate, the excess active material paste is scraped with a squeegee to obtain a specified amount of active material. The active material paste may adhere to the squeegee mounted on the filling machine. When the active material paste (hereinafter referred to as “paste waste”) attached to the squeegee falls on the surface of the electrode plate, the paste is not flattened even if the electrode plate surface is compressed with a molding roller that compresses the active material paste. Waste may remain as protrusions. Since this paste scrap is attached to the squeegee, the amount of water decreases, and it gradually hardens and falls and adheres to the surface of the electrode plate. However, it is not completely embedded in the active material paste, but remains as a protrusion protruding from the surface of the electrode plate after the next step.

  Also, when filling each grid substrate with active material paste while transporting a plurality of grid substrates placed flat at intervals, the active material paste that has entered the gap between adjacent grid substrates is transported to the molding roller position as it is. In some cases, the paste scraps adhere to the forming roller as paste scraps, and the paste scraps are transferred to the back surface of the electrode plate as the forming roller rotates. Also in this case, since the moisture content of the paste waste decreases while being transported and is transferred in a hard state, the paste waste is not completely embedded in the active material paste even when pressed with a forming roller. May remain as protrusions protruding from the surface of the electrode plate.

  The protrusions caused by these paste scraps remain on the surface of the electrode plate when the battery is assembled after the electrode plate aging and drying process, and the electrode plate group in which the positive electrode plate and the negative electrode plate are alternately laminated via the separator plate is formed. When pressurizing and inserting into the battery case, pressure concentrates on the protrusions, compressing the separator and reducing the distance between the positive and negative electrodes, increasing the possibility of an infiltration short circuit. Further, when the height of the protrusion is high or the strength of the separator is low, the protrusion may break through the separator and a short circuit may occur between the electrode plates.

  Patent Document 3 discloses a technique for attaching a glass mat separator after filling with an active material paste, but it is a technique for preventing displacement of the electrode plate, and a general glass mat retainer with low strength is used. If the paste scraps adhering to the surface of the electrode plate remain as protrusions after the battery assembly process, it is difficult to prevent the penetration short circuit and the short circuit that occurs by breaking through the retainer.

An object of the present invention is to provide a control valve type lead-acid battery capable of preventing a short circuit between a positive electrode plate and a negative electrode plate caused by a protrusion generated due to paste dust adhering to the electrode plate surface.
Another object of the present invention is to provide a control valve type lead-acid battery capable of suppressing a permeation short circuit caused by a protrusion generated due to paste dust adhering to the electrode plate surface.
Still another object of the present invention is to provide a control valve type lead-acid battery capable of suppressing a floating short circuit that occurs due to the active material collapsed from the electrode plate floating in the electrolyte when the electrolyte is injected. There is.

  The present invention is directed to a method of manufacturing an electrode plate through a step of pressing an active material paste with a forming roller after filling the active material paste into a lattice substrate.

  That is, a positive electrode plate and a negative electrode plate are manufactured by filling the active material paste into the lattice substrate and then pressing the active material paste from both sides of the lattice substrate with a forming roller, and using the positive and negative electrode plates, control valve type lead In the production method for assembling the storage battery, either the positive electrode plate or the negative electrode plate is filled with the active material paste on the lattice substrate and then covered with a glass nonwoven fabric mainly composed of glass fibers from both sides of the lattice substrate. It manufactures through the process pressed with the forming roller from the said glass nonwoven fabric. And the glass fiber whose tensile elasticity modulus is 72 GPa or more is selected as said glass fiber, It is characterized by the above-mentioned.

  In the present invention, after the active material paste is filled into the lattice substrate, the active material paste is pressed from both sides of the lattice substrate by passing it through a gap formed by at least a pair of forming rollers, and the front and back surfaces of the electrode plate are smoothed. To. At this time, either one of the positive electrode plate and the negative electrode plate can be prevented from adhering to the forming roller by covering the both sides of the lattice substrate with a glass nonwoven fabric. And, by adopting glass fiber with a tensile modulus of 72 GPa or more, even if the electrode plate with paste scraps attached to the electrode plate surface is passed while applying pressure between the forming rollers, the piercing strength is high and the deformation amount Because there is little, the pressure which pushes paste waste into the active material paste is high, and the electrode plate surface is made flatter than when a glass nonwoven fabric mainly composed of glass fibers having a tensile elastic modulus smaller than 72 GPa is arranged. The paste waste does not break through the glass nonwoven fabric, and a short circuit between the electrode plates can be prevented. Furthermore, since the deformation amount in the thickness direction of the glass nonwoven fabric is small, even if pressure in the thickness direction is applied to the positive electrode plate and the negative electrode plate with protrusions remaining on the surface of the electrode plate, the distance between the electrode plates is unlikely to be shortened. It becomes possible to suppress the occurrence of a short circuit.

  In the specification of the present application, covering from both sides of the lattice substrate with the glass nonwoven fabric means that the glass nonwoven fabric is biting into the active material paste as well as the state where the glass nonwoven fabric is in contact with the active material paste filled in the lattice substrate. It also includes the state.

The glass fiber is preferably ECR glass fiber (tensile elastic modulus 72.5 GPa) or S glass fiber (tensile elastic modulus 84.3 GPa) having good acid resistance. Even when the lead storage battery is used for a long period of time, the glass fiber is hardly deteriorated, and the active material that has become muddy and brittle can be prevented from falling off the lattice substrate by holding the lattice substrate. In addition, selection of E glass fiber (tensile elastic modulus 72.5 GPa) and AR glass fiber (tensile elastic modulus 73.0 GPa) is not impeded.
The tensile modulus of elasticity of the glass fiber is as described in Japanese Society for Composite Materials 2007, No. 4 It was described with reference to the description of P143.

  The apparent density of the glass nonwoven fabric is preferably 0.1 g / mL or more. The higher the apparent density, the higher the piercing strength, and the projections on the electrode plate surface caused by paste dust and the like do not break through the glass nonwoven fabric, and the effect of preventing the short circuit between the positive electrode plate and the negative electrode plate is even higher. Become. In addition, the glass nonwoven fabric whose apparent density is larger than 0.3 g / mL has high electrical resistance, and the discharge performance of a lead storage battery falls. Moreover, the produced glass nonwoven fabric is hard and becomes brittle, and handling becomes difficult.

  In addition, by covering the inner area surrounded by the frame bone of the lattice substrate with a glass nonwoven fabric including the frame bone, the active material of the frame bone part is peeled off by vibration etc. and falls between the positive electrode plate and the negative electrode plate It is possible to prevent short circuit. Furthermore, it is possible to prevent a short circuit that occurs due to the active material being peeled off due to vibration of the storage battery and falling between the positive and negative electrodes, or a floating short circuit that occurs when the active material collapses and floats in the electrolytic solution when the electrolytic solution is injected.

  According to the present invention, it is possible to realize a control valve type lead-acid battery capable of suppressing a permeation short circuit that occurs due to paste dust adhering to the electrode plate surface and preventing a short circuit due to breaking through the separator. It becomes.

It is the schematic of the filling machine, the forming press, and glass nonwoven fabric supply position which are one Example of this invention. It is a figure which shows the relationship between the apparent density and piercing strength of an ECR glass nonwoven fabric and a C glass mat retainer.

Hereinafter, embodiments of the present invention will be described in detail.
<Production of control valve type lead acid battery>
The lattice substrate described in the present invention is manufactured by casting, expanding, or stamping lead or a lead alloy. A lead alloy can contain tin, calcium, antimony, etc., using lead as a main raw material.
The active material paste used in the present invention is prepared by mixing polyethylene terephthalate (PET) fiber, lignin (in the case of negative electrode), red lead (in the case of positive electrode), etc. with lead powder mainly composed of lead monoxide, and water and dilute. A positive electrode active material paste and a negative electrode active material paste prepared by kneading with sulfuric acid can be used.

  After the active material paste is filled into the lattice substrate 1 passing under the active material filling machine 4 including the active material charging machine 3 containing the active material paste described above, the lattice substrate is used by using a pair of molding rollers 7 and 8. 1 is pressed from both sides to produce a filled electrode plate. The filling amount of the active material paste to be filled into the lattice substrate 1 is calculated based on the design capacity of the battery and is filled so that the vertical and horizontal bones of the lattice substrate 1 are covered. After that, while the filled active material paste is soft, a molding process is performed in which pressure is applied to the active material paste by a pair of molding rollers 7 and 8 from both sides of the lattice substrate 1. Here, the pair of forming rollers 7 and 8 is configured to sandwich the charged electrode plate that is being conveyed from above and below and convey while applying pressure by rotation thereof, and form an active material layer having a substantially uniform thickness. be able to. A plurality of pairs of forming rollers are arranged and the filled electrode plate is pressed, so that the filled active material layer can be made more uniform.

  For either the positive electrode plate or the negative electrode plate, the width of the filling electrode plate from both sides of the filling electrode plate in the direction perpendicular to the conveying direction of the filling electrode plate before being pressed by the pair of forming rollers while moving the filling electrode plate by the conveying belt. A glass non-woven fabric is supplied, and the electrode plate surface is covered by applying a pressure to the glass non-woven fabric using a forming roller in a state where the filled electrode plate is sandwiched between the glass non-woven fabric. The unnecessary glass nonwoven fabric is cut along the outer periphery of the frame bone of the electrode plate using the glass nonwoven fabric cutter 9 after the molding press. Therefore, the electrode plate surface including the frame bone of the filled electrode plate is covered with the glass nonwoven fabric.

  Thereafter, a plurality of positive and negative electrode plates produced by aging and drying are alternately laminated via separators made of C glass fibers called retainers, and the ears of the laminated same polarity plates are connected with straps. Thus, the electrode plate group is configured. This electrode plate group is accommodated in the battery case by applying a predetermined pressure from the stacking direction of the positive and negative electrode plates, and the control valve type lead-acid battery is assembled by closing the opening of the battery case with a lid with a safety valve, and a predetermined amount of electrolyte To form a battery case.

When a plurality of cell chambers are provided in the battery case, electrode plate groups are accommodated in each cell chamber, and predetermined straps are provided by mutually connecting straps having opposite polarities of electrode plate groups accommodated in adjacent cell chambers. A lead-acid battery having a rated voltage and a rated capacity of is configured. In the case of a single cell battery case, terminals of a plurality of lead storage batteries can be connected in parallel or in series using a conductive plate to constitute a battery pack having a predetermined voltage and capacity.
The material of the battery case is not particularly limited, and specifically, polypropylene, ABS, modified PPE (polyphenylene ether) or the like can be used.

The lid is not particularly limited as long as it closes the opening of the battery case described above, and the same or different material can be used for the lid. However, it is preferable to use a material having a thermal expansion coefficient similar to that of the battery case so that the lid body does not fall off due to thermal deformation when heated.
The control valve is for discharging excess gas that could not be absorbed by the gas absorption reaction of the negative electrode out of the oxygen tank generated during charging. The material is preferably a material excellent in chemical resistance (acid resistance, silicon oil resistance), abrasion resistance, and heat resistance, specifically, fluororubber.
The electrolytic solution described in the present invention is not particularly limited, but is prepared by diluting sulfuric acid with purified water and preparing a concentration of about 30% by mass. This can be adjusted to an appropriate concentration in consideration of battery capacity, life, etc. (additives such as magnesium sulfate and silica gel may be added depending on the characteristics) and injected into the battery case.

  Examples of the present invention will be described in detail below.

<Production of glass nonwoven fabric>
In this example, glass nonwoven fabrics with different apparent densities were prepared by adjusting the amount of glass fibers during paper making, using ECR glass fibers (tensile modulus of elasticity 72.5 GPa) as described in JIS R3410 as the main component of the glass nonwoven fabric. Thereafter, the glass binder was molded and pressed using an organic binder, and a glass nonwoven fabric having a thickness of 100 μm when pressed with a pressure of 19.6 kPa was produced. (Examples 1-4 and Comparative Example 1)
In addition, a case of using a C glass mat retainer (nonwoven fabric of C glass fiber (tensile elastic modulus 68.6 GPa)) manufactured by Nippon Sheet Glass Co., Ltd., having a thickness of 300 μm when pressed with a pressure of 19.6 kPa. It was set as Comparative Example 2.

(Measurement of apparent density of glass nonwoven fabric)
About 0.05 g of each of the glass nonwoven fabrics of Examples 1 to 4, Comparative Example 1 and Comparative Example 2 was cut out, and the apparent density was measured using AutoPore IV 9500 V1.07. Table 1 shows the measurement results of the apparent density.

(Puncture strength test)
Each glass nonwoven fabric was cut into a circle having a diameter of 4 cm, and the piercing strength was measured using REOMETER MRM-2002J manufactured by FUDOH. The shape of the measuring jig used was a spherical rod having a diameter of 3 mm fixed to the tip of a cylindrical rod having a diameter of 2 mm. The displacement speed of the measuring jig is 5 cm / min. The average value of the measured values measured three times was defined as the piercing strength. FIG. 2 shows the relationship between the apparent density and the piercing strength.

  From FIG. 2, the glass nonwoven fabric using ECR glass fibers (Comparative Example 1, Examples 1 to 4) has high piercing strength even if the apparent density is smaller than that of the glass nonwoven fabric using C glass fibers (Comparative Example 2). I understand that. Further, it can be seen that the ECR glass nonwoven fabric having the same apparent density as that of the C glass nonwoven fabric has a puncture strength of about 1/3, although the thickness is 1/3. Further, the apparent density and the piercing strength of the ECR glass nonwoven fabric are in a proportional relationship, and the piercing strength increases as the apparent density increases. However, when the apparent density increases, the electrical resistance increases and the discharge performance of the lead-acid battery decreases, or the glass nonwoven fabric becomes hard and brittle, and breakage and breakage are likely to occur during handling.

<Preparation of positive electrode plate>
A grid substrate (vertical: 144 mm × width: 145 mm × thickness: 3.2 mm) containing lead as a main raw material was filled with a positive electrode active material paste having a density of 4.6 g / cm ³ , and then A specification: Example 1 A positive electrode plate whose front and back surfaces were covered with an ECR glass nonwoven fabric before roller molding and B specification: 2000 positive electrode plates each having a paste-like active material on the front and back surfaces were prepared. The electrode plate filled with the positive electrode active material paste was made into an unformed positive electrode plate through the following aging conditions 1 to 3 and drying conditions.
Aging condition 1: temperature: 80 ° C., humidity: 98%, time: 10 hours Aging condition 2: temperature: 65 ° C., humidity: 75%, time: 13 hours Aging condition 3: temperature: 40 ° C., humidity: 65% Time: 40 hours Drying conditions: Temperature: 60 ° C, Time: 24 hours

(Comparison of electrode plate thickness variation due to paste scrap)
After aging and drying, the thickness of the unformed positive electrode plate was measured at the upper 3 points, the central 3 points, and the lower 3 points using a caliper.
As a result, the ratio of the measurement points where the thickness measurement value t of the electrode plate thickness t is 3.4 mm <t ≦ 3.5 mm with respect to the thickness design value T: 3.3 mm of the non-chemicalized positive electrode plate is A specification: 0 The ratio of measurement points of 4%, B specification: 3.5%, 3.5 mm <t ≦ 3.6 mm is A specification: 0.2%, B specification: 2.0%, 3.6 mm <t ≦ The ratio of measurement points of 3.7 mm is A specification: 0.1%, B specification: 1.2%, and A specification: the thickness variation of the unformed positive electrode plate when the active material surface is covered with ECR glass nonwoven fabric. It can be seen that the effect of reducing the effect is great. This is because paste scraps attached to the surface of the electrode plate during filling of the active material paste were pushed into the active material paste by the ECR glass nonwoven fabric during roller molding, and the protrusions on the surface of the electrode plate were reduced. This is thought to be because it was not transferred to the electrode plate and adhered to the surface of the electrode plate.

<Preparation of negative electrode plate>
A grid substrate (vertical: 145 mm × horizontal: 147 mm × thickness: 2.2 mm) containing lead as a main material was filled with a negative electrode active material paste having a density of 4.4 g / cm ³ .
The electrode plate filled with the negative electrode active material paste is
Aging condition: temperature: 40 ° C., humidity: 98%, time: 40 hours Drying condition: temperature: 60 ° C., time: 24 hours aging and drying conditions were performed to obtain an unformed negative electrode plate.

<Production of control valve type lead acid battery>
Of the prepared unformed positive electrode plates, the measured value t of the electrode plate thickness is the upper 3 points, the central 3 points, and the lower 3 points in the respective plate thickness ranges (3.4 mm <t ≦ 3.5 mm, 3 .5 mm <t ≦ 3.6 mm, 3.6 mm <t ≦ 3.7 mm) were selected. Two selected unchemically formed positive electrode plates and the above-described two negative electrode plates were alternately laminated through a retainer having a thickness of 1.5 mm when pressurized to 19.6 kPa, thereby producing an electrode plate group. The produced electrode plate group is inserted into the battery case, and after the positive electrode terminal and the negative electrode terminal are welded to the electrode plate group, the battery case is sealed. Next, an electrolyte containing dilute sulfuric acid as a main component was injected from the exhaust plug port, a control valve was attached, and a battery case was formed to produce a control valve type lead storage battery.
The battery tank formation conditions were as follows: water temperature: 40 ° C., amount of electricity applied: 250% of the theoretical amount of electricity generated by the positive electrode active material, and time: 60 hours.

(Penetration short circuit test)
The battery after the formation of the battery case was left (a) in a thermostat having an ambient temperature of 25 ° C. for 24 hours, and (b) the positive electrode and the negative electrode were short-circuited with a resistance of 1.67Ω, and constant resistance discharge was performed for 24 hours. After the constant resistance discharge, the resistance was removed and (c) left for 1 week. After being allowed to stand, (d) charging at a constant current until 245V was reached at 2A, and then charging at a constant voltage at 2.45V was performed for a total of 24 hours.
Then, said (a)-(d) was made into 1 cycle, and the cycle was repeatedly implemented until the short circuit generate | occur | produced this about said A specification and B specification.

  The results of the penetration short circuit test are shown in Table 2. From Table 2, it can be seen that a thin plate with a measured thickness t of the plate is superior in short-circuit performance compared to a thick plate. No. 1, 4 and 2, 5 are compared, No. of A specification (a positive electrode plate covered with an ECR glass nonwoven fabric). Nos. 1 and 2 are Nos. B of the B specification (positive and negative electrodes with the front and back surfaces being pasty active materials). It can be seen that the short circuit performance is superior to those of 4 and 5. This is thought to be because the active material can be prevented from collapsing during the injection by covering the surface of the electrode plate including the frame bone with the ECR glass nonwoven fabric, so that the floating short circuit caused by the active material floating can be suppressed. .

○：３サイクル以上、△：１〜２サイクル、×：１サイクル未満

○: 3 cycles or more, Δ: 1-2 cycles, ×: less than 1 cycle

DESCRIPTION OF SYMBOLS 1 Lattice substrate 2, 10 Conveyor belt 3 Active material charging machine 4 Active material filling machine 5, 6 Glass nonwoven fabric 7, 8 Forming roller 9 Glass nonwoven fabric cutting machine

Claims (3)

A positive electrode plate and a negative electrode plate are manufactured through a process of filling the active material paste into the lattice substrate and then pressing the active material paste from both sides of the lattice substrate with a forming roller. In the manufacturing method to assemble,
Either the positive electrode plate or the negative electrode plate is filled with the active material paste on the lattice substrate, and then covered with a glass nonwoven fabric mainly composed of glass fibers from both sides of the lattice substrate, and the active material paste is molded from above the glass nonwoven fabric. Manufactured through a process of pressing with a roller,
A method for producing a valve-regulated lead-acid battery, wherein a glass fiber having a tensile elastic modulus of 72 GPa or more is selected as the glass fiber, and the apparent density of the glass nonwoven fabric is 0.1 g / mL or more .   The method for manufacturing a control valve type lead-acid battery according to claim 1, wherein the glass fiber is one of ECR glass and S glass. 2. The method of manufacturing a control valve type lead-acid battery according to claim 1, wherein the glass fiber is ECR glass.

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