RU2439752C1 - Manufacturing method of electrodes for electrochemical current source and device for method implementation - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: electrode manufacturing method is implemented by application of active material to substrate, by placing substrate between ribbons of filter materials, by the first and next drawing of substrate through rollers and subsequent cutting of substrate into electrodes. The first drawing of substrate from side of active material is carried by two ribbons made of materials with different porosity and pressed to each other by their surfaces. External ribbon that contacts active material is made of material with high porosity with pore size of 10-70 mcm, e.g. of non-woven polypropylene or polyethylene; internal ribbon is made of material with low porosity and size of pores less than 6 mcm, e.g. of paper. Pressure at the first and next drawings shall be within range of 4.5-11 kg/cm². Device for electrode production contains forwarding mechanism in the form of belt conveyor, bunker for material application, frame with installed upper and lower receiving driving rolls and feed rolls, roller for the first and next drawing and electrode cutting mechanism. Between rollers for the first and next drawing there are upper and lower filtering ribbons made of low-porosity material and located at respective rolls. Device is equipped with one or two continuous filtering ribbons made of high-porosity material, which are installed at tolls for the first drawing and directly over top of one or two ribbons with low porosity (when substrate is drawn at one or both sides). Width of continuous ribbon corresponds to width of low-porosity ribbon. Support rotating rollers with continuous ribbon are installed at frame. Axes of support rollers are installed in parallel to the first drawing rollers. The first drawing rollers for the first drawing are located inside continuous ribbon runs in the same place as support rollers. Ration of thickness for materials with high and low porosity is 1:1-1:2.1.

EFFECT: reduction of material process losses and reduction of reject rate by weight of active material in electrode.

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Description

The invention relates to the field of electrical engineering and can be used for the production of electrochemical current sources, such as batteries and supercapacitors.

A known method of manufacturing electrodes for an electrochemical current source by discrete deposition of active mass on a substrate and rolling between the rollers on which a layer of filter material is applied (patent RU No. 2140680, IPC 6 H01G 9/00, publ. 1999).

The disadvantage of this method of manufacturing electrodes is its low productivity due to the intermittent process of applying the active material to a separate substrate, laying the separator and rolling each electrode with a separator by rolls with filter material.

A device for the manufacture of electrodes for an electrochemical current source, comprising a spreading hopper, rolling rolls, two moving endless tapes covering the rolls, and devices for washing, spinning and drying tapes (USSR author's certificate No. 95278, IPC Н01М 4/20, publ. 1953 g.).

The disadvantages of this device are the receipt of defective electrodes due to the insufficient amount of the active mass in the electrode due to the adherence of the active mass to the filter cloth and tearing of the mass from the applied layer, as well as the complexity of the device due to the availability of devices for washing, pressing and drying the tapes.

A known method of manufacturing electrodes for an electrochemical current source and device for its implementation (USSR author's certificate No. 1400405, IPC 4 Н01М 4/26, publ. 1995) - adopted as a prototype.

The method includes applying an active mass to a substrate, first and subsequent rolling by rolls of a substrate located between the belts of filter material with low porosity.

A device for implementing this method comprises a transporting mechanism, a spreading hopper, a frame with receiving drive and feeding reels mounted on it, rolls of the first and subsequent rolling, tapes of filter material with low porosity, passed between the rolls from the corresponding bobbins.

The disadvantage of this method and device for the manufacture of electrodes is the increased technological loss of the active mass and the receipt of defective electrodes due to the insufficient amount of active mass in the electrode due to the sticking of the active mass to the filter cloth and tearing of the mass from the deposited layer during the first and subsequent rolling. This is caused by the use of a filter cloth made of low-porosity material (with good wetting properties), which promotes capillary absorption into the tissue of the electrolyte located in the upper layer of the active mass and promotes the adhesion (suction) of the active mass to the filter cloth.

An object of the invention is to reduce the technological loss of materials and reduce scrap by the amount of mass in the electrode.

The specified technical result is achieved by the fact that in the known method of manufacturing an electrode for an electrochemical current source, comprising applying an active mass to a substrate, first and subsequent rolling of the substrate in rolls between the tapes of the filter material with low porosity and subsequent cutting of the substrate into separate electrodes, the first rolling of the substrate from the side of the active mass, they are carried out simultaneously by two tapes, directly superimposed on each other by their surfaces, while as a material in the external tape in contact with the active mass, use a filter material with high porosity with a pore size of 10-70 μm, and as a low-porous filter material of the inner tape use a material with a pore size of not more than 6 μm, while the ratio of the thickness of the material with high porosity to thickness material with low porosity is taken equal to 1: 1-1: 2,1, and the pressure during rolling is taken in the range of 4.5-11 kg / cm ² .

Moreover, as a material with high porosity, for example, non-woven, or woven, or sintered polyolefins, such as, for example, polypropylene or polyethylene, are taken, and, for example, paper is used as a material with low porosity.

The specified technical result is achieved by the fact that in the known device for the manufacture of electrodes for an electrochemical current source containing a conveying mechanism, a spreading hopper, a frame with receiving drive and feed reels mounted on it, rolls of the first and subsequent rolling, tapes of filter material with low porosity, passed between the rolls from their respective bobbins, and a mechanism for cutting electrodes, the device is additionally equipped with one or two endless filter belts of highly porous material placed in the rolls of the first rolling and located directly on the outer surface of one or two strips of material with low porosity, and is equipped with support rollers mounted on a frame on which an endless tape is located, while the axes of the support rollers are parallel to the axes of the bobbins the first rolling, which are located inside the branches of the endless tape and are in the same plane with the rollers, while the pore size of the highly porous material is 10-70 μm, and the pore size is low Risto material is not more than 6 microns, and the thickness ratio of a material of high porosity to the material thickness of the low porosity is 1: 1-1: 2.1.

In addition, the width of the endless ribbon of filter material with high porosity is equal to the width of the ribbon of filter material with low porosity, while non-woven, or woven, or sintered polyolefins, such as, for example, polypropylene or polyethylene, and as a material with low porosity, for example, paper is used.

In the inventive method and device for the manufacture of electrodes in the preliminary rolling of the substrate from the side of the active mass with two tapes directly applied to each other by their surfaces, while the filter material with high porosity with size is used as the material of the external endless tape in contact with the active mass pores 10-70 μm, and as a low-porous filter material of the inner tape use a material with pore sizes of not more than 6 μm, with a ratio of thickness m Therians high porosity to the material thickness of the low porosity of 1: 1-1: 2.1, and the rolling pressure equal to 4,5-11 kg / cm ^2, reduced loss of materials and process start falling marriage count mass in the electrode .

This is achieved by the fact that when rolling an active mass deposited on a substrate with an endless ribbon of filter material with high porosity with a pore size of 10-70 μm and simultaneously paired with a ribbon of material with low porosity with a pore size of not more than 6 μm, the mass does not adhere to the filter material with high porosity, which is the accumulator of the selected electrolyte, due to the low capillary rise of the electrolyte and, accordingly, due to the low value of adhesion while ensuring the required rate of removal of excess electrolyte by a low porosity tape material, which is a capillary “pump”, which helps to reduce technological losses of the active material and ensure the quality of the electrode.

The ratio of the thickness of the material of the tapes with high porosity to the thickness of the material with low porosity, equal to 1: 1-1: 2,1, provides the optimal rate of selection of the electrolyte and leaving the required amount of it in the mass, which ensures the quality of the electrode.

The value of the pressure during rolling in the range of 4.5-11 kg / cm ² allows you to get electrodes with the optimal density of the active mass and eliminates the deformation and rush of the substrate, which reduces technological losses of materials and ensures the quality of the electrode.

Equipping the device with one or two endless filter belts of highly porous material, placed in the rolls of the first rolling and located directly on the outer surface of one or two belts of material with low porosity, allows to obtain high-quality electrodes regardless of whether it is applied on one side or on both sides active mass on the substrate.

The presence of support rollers mounted on a frame on which an endless tape is located, the installation of rollers with their axes parallel to the axes of the first rolling bobbins and the location of the bobbins inside the branches of the endless ribbon ensure the connection of tapes of materials with different porosity with their surfaces in the first rolling rolls and during operation contributes high-quality electrodes.

No technical solutions coinciding with the set of essential features of the claimed invention have been identified, which allows us to conclude that it meets such a patentability condition as “novelty”.

The claimed essential features of the claimed invention, predetermining the receipt of the specified technical result, do not explicitly follow from the prior art, which allows us to conclude that they comply with such a condition of patentability as "inventive step".

The essence of the proposed method is illustrated in the drawing, where

figure 1 schematically shows a device for the manufacture of electrodes of an electrochemical current source when rolling the substrate with the applied active mass on one side;

figure 2 is the same when rolling the substrate with the applied active mass on both sides;

figure 3 - site of the first rolling.

A device for the manufacture of electrodes by the claimed method contains a conveyor mechanism in the form of a conveyor belt - 1, spreading hopper - 2, frame - 3 with upper receiving drive reels - 4 and feeding reels - 5 mounted on it, lower receiving reel - 6 and feeding reel - 7 , rolls - 8 first and rolls - 9 subsequent rolling and mechanism - 10 cutting electrodes. Between the pairs of rolls of the first and subsequent rolling, the upper filter belts - 11 and the lower filter belt - 12, made of low-porosity material, were passed. The device is equipped with one endless tape - 13 (when rolling the substrate on one side. Figure 1) or two endless filter tapes - 13 and 14 (when rolling the substrate on two sides, Figure 2) of highly porous material that are installed in the rolls of the first rolling and located directly on the outer surface of one or two tapes - 11 of a material with low porosity. The width of the endless tape corresponds to the width of the tape of low porosity material. Supporting rotating rollers - 15 are mounted on the frame, on which an endless tape is mounted. Axes - 16 support rollers are installed parallel to the axes - 17 reels of the first rolling. The first rolling bobbins are located inside the branches of the endless belt and are in the same plane with the support rollers (Figure 3). The pore size of the highly porous material is 10-70 μm, and the pore size of the low-porous material is not more than 6 μm. As a filter material with high porosity, for example, non-woven, or woven, or sintered polyolefins, such as polypropylene or polyethylene with low values of adhesion to the active mass, can be used, and as filter material of tapes with a low porosity, for example, paper. The ratio of the thickness of the material of the tape with high porosity to the thickness of the material with low porosity is 1: 1-1: 2.1. The drawing shows the substrate - 18 in the form of a continuous tape with an active mass of 19 and an electrode of 20.

A method of manufacturing electrodes for an electrochemical current source is as follows.

Made the manufacture of the electrode with the application of the active mass on one side of the substrate (Figure 1).

The substrate - 18 in the form of a tape is placed on the lower tape - 12 from a filter material with low porosity, which is placed on the conveyor - 1 and includes a mechanism for pulling the tape (not shown). At the same time include the upper - 4 and lower - 6 receiving drive bobbins. Then the spreading hopper - 2 is applied active mass - 19 on one side of the substrate. After spreading the substrates from the side of the active mass, the first rolling is carried out by rollers - 8 simultaneously with two tapes directly applied to each other by their surfaces (an endless tape and a tape paired with it - 11). When this happens, the movement of the endless tape on the supporting rotating rollers - 15, and the tape - 11 is wound from the reel - 5 to the take-up reel - 4. As a filter material of the endless tape - 13 in contact with the active mass, a material with high porosity with a pore size is used 10-70 microns, for example, non-woven polypropylene with a thickness of 70-150 microns, and as the filter material of the tapes - 11, 12 use a material with low porosity with a pore size of not more than 6 microns, for example paper with a thickness of 70 microns. As a filter material with high porosity with a pore size of 10-70 μm, for example, non-woven, or woven, or sintered polyolefins, such as polypropylene or polyethylene with low values of adhesion to the active mass, can be used. The speed of the first and subsequent rolling is chosen equal to V = 2-2.5 m / min. During the first rolling process, the active mass is densified and the electrolyte penetrates through the filter material of the endless tape - 13 without mass adhesion to the tape material due to the low wetting properties of the nonwoven polypropylene by electrolyte and the excess electrolyte is removed by the filter tape - 12 made of a material with low porosity. In the subsequent rolling of the smeared substrate in rolls - 9, the excess electrolyte is finally removed and the mass is compacted to the final electrode size in thickness without mass adhesion to the tape material due to the previous mass compaction and removal of the electrolyte excess from the upper layer of the active mass.

The thickness of the rolling strips is selected from the ratio of the thickness of the tape of the material with high porosity to the thickness of the material with low porosity in the range from 1: 1 to 1: 2.1.

The specified ratio provides the optimal rate of selection (absorption) of the electrolyte and leaving a given amount of it in the mass, necessary to reduce the internal resistance of the electrolyte and to provide the required contact between the particles of the active mass, as well as to recharge the electrode and the separator with electrolyte, which ensures the quality of the electrode.

The pressure during the first and subsequent rolling is taken in the range of 4.5-11 kg / cm ² .

After rolling by the mechanism - 10, the substrate - the tape - is cut into electrodes - 20 of the required size.

Rolling the substrate using a filter tape of a material with high porosity is carried out in contact with an active mass located on one or both sides of the substrate.

In the manufacture of spread electrodes, for example, for lead-acid or alkaline batteries with an active mass deposited on both sides of the substrate (perforated metal tape, foam nickel or carbon foam), the active mass is rolled by two tapes located on each of both sides of the substrate. In this case, the second lower unit is installed mirror-like to the upper node of the first rolling, which is structurally similar to the upper one (Figure 2).

In the manufacture of electrodes for a supercapacitor, where, for example, fibrous ion-conducting material is used as a substrate, and the active mass is applied on one side of the substrate, rolling through two tapes of filter material with high and low porosity is performed on one side (from the active mass side) and, on the other hand (lower), they are rolled with a tape from a material with low porosity.

Example 1

A substrate of fibrous ion-conducting material, for example, glass fiber for an electrochemical supercapacitor with a width of 145 mm, is laid on the lower ribbon of filter low-porous material in the form of paper with a pore size of not more than 6 μm, the substrate is moved with a tape and the active mass is applied to the substrate. As the active mass, a mixture of the following composition mixed with alkaline electrolyte (KOH) was used: activated carbon — 85% and soot — 15%. After spreading the substrate, the active mass layer is initially rolled with a filter tape - 13, for example, of non-woven polypropylene with a pore size of 30-35 microns, and with a tape located on it - 11 (paired with it) from a low-porous material with a pore size of no more than 3-5 microns. The thickness of the tape of highly porous material is taken equal to 70 μm, and the thickness of the tape of low-porous material is 70 μm (the ratio is 1: 1). Rolling is carried out at a speed of pulling the upper filter belts - 11, 13 and the lower belt - 12 through the rolls V = 2.2 m / min at a roll pressure of 7.8 kg / cm ² .

Subsequent rolling is performed through a tape of filtering low-porous material in the form of paper with a pore size of not more than 3-5 microns and a thickness of 70 microns to an electrode thickness of 0.8 mm.

Then the mechanism - 10 produce a segment of the substrate in the size of the electrode.

In the manufacture of electrodes, no adhesion of the active mass to the filter belts was observed, as a result of which there were no technological loss of materials, the amount of mass in the electrode, as well as the rate of selection (absorbency) of the electrolyte and the preservation of a given amount of it in the mass, met the requirements.

Example 2

The substrate with the applied active mass is rolled from the active mass side with two paired filter belts, the outer one of which is made of non-woven polypropylene with a pore size of 70 μm, a thickness of 150 μm, and a tape of low-porous material with a pore size of 6.0 μm and a thickness of 70 μm (the ratio is 1: 2.1) and rolled with a speed of pulling the filter tape through the rolls V = 2.2 m / min at a pressure of the rolls with a force of 11 kg / cm ² .

Subsequent rolling is carried out through a tape of filtering low-porous material in the form of paper with a pore size of 6 μm and a thickness of 70 μm to an electrode thickness of 0.8 mm.

In the manufacture of electrodes, no adhesion of the active mass to the filter belts was observed, as a result of which there were no technological loss of materials, the amount of mass in the electrode, as well as the rate of selection (absorbency) of the electrolyte and the preservation of a given amount of it in the mass, met the requirements.

Example 3

The substrate with the applied active mass is rolled from the active mass side with two paired filter belts, the outer one of which is made of non-woven polypropylene with a pore size of 10 μm, a thickness of 100 μm, and a tape of low-porous material with a pore size of 3-5 μm and a thickness of 70 μm (the ratio is 1: 1.4), and rolled at a speed of pulling the filter tape through the rolls V = 2.4 m / min at a pressure of the rolls with a force of 4.5 kg / cm ² .

Subsequent rolling is performed through a tape of filtering low-porous material in the form of paper with a pore size of 3-5 μm and a thickness of 70 μm to an electrode thickness of 0.8 mm.

In the manufacture of electrodes, no adhesion of the active mass to the filter belts was observed, as a result of which there were no technological loss of materials, the amount of mass in the electrode, as well as the rate of selection (absorbency) of the electrolyte and the preservation of a given amount of it in the mass, met the requirements.

Example 4

The substrate with the applied active mass is rolled from the active mass side with two paired filter belts, the outer one of which is made of non-woven polypropylene with a pore size of 71 μm, a thickness of 170 μm, and a tape of low-porous material with a pore size of 7 μm and a thickness of 70 μm (ratio is 1: 2.4), and rolled at a speed of pulling the filter tape through the rolls V = 2.0 m / min at a roll pressure of 11.1 kg / cm ² .

Subsequent rolling is performed through a tape of filtering low-porous material in the form of paper with a pore size of 7 μm and a thickness of 70 μm to an electrode thickness of 0.8 mm.

In the manufacture of electrodes, adhesion of the active mass to the polypropylene filter tape was not observed, however, the active mass was torn from the substrate during subsequent rolling due to insufficient electrolyte selection during the first rolling, which necessitated a decrease in the speed of movement to 1 m / min, resulting in a decrease in the productivity of electrode manufacturing . In addition, during rolling, extrusion of the active mass at the edges of the substrate was observed, which impaired the quality of the electrodes.

Example 5

The substrate with the applied active mass is rolled from the active mass side with two paired filter belts, the outer one of which is made of non-woven polypropylene with a pore size of 9.0 μm, a thickness of 63 μm, and a tape of low-porosity material with a pore size of 2.0-3, 0 μm and a thickness of 70 μm (the ratio is 1: 0.9), and rolled at a speed of pulling the filter tape through the rolls V = 2.1 m / min at a pressure of the rolls with a force of 4.4 kg / cm ² .

Subsequent rolling is carried out through a tape of filtering low-porous material in the form of paper with a pore size of 2-3 microns and a thickness of 70 microns to an electrode thickness of 0.8 mm.

In the manufacture of electrodes, gusts of the filter tape from non-woven polypropylene were observed due to its inadmissible thickness, the adhesion of the active mass to the tape, and insufficient selection of the electrolyte by the filter material due to insufficient pressure during rolling.

Thus, the claimed method and device for the manufacture of electrodes for an electrochemical current source meets the condition of patentability "industrial applicability".

The proposed method and device compared to the prototype can reduce the technological loss of materials and reduce the marriage by the amount of active mass in the electrode.

Claims (9)

1. A method of manufacturing electrodes for an electrochemical current source by applying the active mass to the substrate, first and subsequent rolling of the substrate in the rolls between the tapes of the filter material with low porosity, and subsequent cutting of the substrate on separate electrodes, characterized in that the first rolling of the substrate from the active side the masses are carried out simultaneously by two tapes, directly applied to each other by their surfaces, while the material of the external tape in contact with the active mass, use a filter material with high porosity with a pore size of 10-70 μm, and as a low-porous filter material of the inner tape, use a material with a pore size of not more than 6 μm, while the ratio of the thickness of the material with high porosity to the thickness of the material with low porosity is taken to be 1: 1-1: 2.1, and the pressure during rolling is taken within 4.5-11 kg / cm ² . 2. The method according to claim 1, characterized in that as a material with high porosity take, for example, non-woven or woven, or sintered polyolefins. 3. The method according to claim 2, characterized in that the polyolefins are, for example, polypropylene or polyethylene. 4. The method according to claim 1, characterized in that, for example, paper is taken as a material with low porosity. 5. A device for the manufacture of electrodes for an electrochemical current source, comprising a transport mechanism, a spreading hopper, a frame with receiving drive and feed reels mounted on it, rolls for first and subsequent rolling, tapes of filter material with low porosity, passed between the rolls from their respective bobbins, and a mechanism for cutting electrodes, characterized in that the device is additionally equipped with one or two endless filter belts of highly porous material, size clipped in the rolls of the first rolling and located directly on the outer surface of one or two strips of material with low porosity, and is equipped with support rollers mounted on a frame on which an endless ribbon is located, while the axes of the rollers are parallel to the axes of the first rolling bobbins, which are located inside branches of an endless ribbon and are in the same plane with the rollers, while the pore size of the highly porous material is 10-70 μm, and the pore size of the low-porous material is not more than 6 μm, the thickness of the material with high porosity to the thickness of the material with low porosity is equal to 1: 1-1: 2.1. 6. The device according to claim 5, characterized in that, for example, non-woven or woven or sintered polyolefins are used as a material with high porosity. 7. The device according to claim 6, characterized in that, for example, polypropylene or polyethylene are used as polyolefins. 8. The device according to claim 5, characterized in that, for example, paper is used as a low porosity material. 9. The device according to claim 5, characterized in that the width of the endless ribbon of filter material with high porosity is equal to the width of the ribbon of filter material with low porosity.

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