阅读说明：本技术 一种耐存储型锂锰电池正极制作方法 (Manufacturing method of storage-resistant lithium-manganese battery positive electrode ) 是由 徐剑锋 于 2021-02-03 设计创作，主要内容包括：本发明公开了一种耐存储型锂锰电池正极制作方法,涉及锂锰电池技术领域,包括如下步骤：1)二氧化锰预处理：2)粘合剂配制：3)粉体加胶：4)搅拌混合：5)压粉：6)摇摆颗粒机造粒：7)筛粉：8)压制正极片：能有效去除锂二氧化锰扣式电池正极材料中的结晶水和水分残留,提高锂锰扣式电池的存储寿命。同时粉体更加均匀,颗粒流动性也更好,制成的成品一致性也更好。使用加装了集流网冲切结构的一次成型设备,使得正极片能够一次成型,极大的提高了产能。(The invention discloses a method for manufacturing a storage-resistant lithium-manganese battery anode, which relates to the technical field of lithium-manganese batteries and comprises the following steps: 1) pretreatment of manganese dioxide: 2) preparing an adhesive: 3) adding glue into the powder: 4) stirring and mixing: 5) powder pressing: 6) granulating by a swing granulator: 7) powder sieving: 8) pressing a positive plate: the method can effectively remove crystal water and water residues in the anode material of the lithium manganese dioxide button cell, and improve the storage life of the lithium manganese dioxide button cell. Meanwhile, the powder is more uniform, the particle fluidity is better, and the consistency of the prepared finished product is better. The one-step forming equipment with the current collecting net punching structure is used, so that the positive plate can be formed at one step, and the productivity is greatly improved.)

1. A manufacturing method of a storage-resistant lithium manganese battery anode and a one-step forming device are characterized by comprising the following steps:

1) pretreatment of manganese dioxide:

and pouring manganese dioxide powder into a tray, leveling the surface of the powder by using a height limiting tool, and simultaneously enabling the powder to be consistent in height and 30-33mm in height. Putting the tray into a side heating blast oven to ensure the temperature uniformity inside the oven, and starting timing to continuously bake for 20 hours after the temperature reaches 380-400 ℃;

2) preparing an adhesive:

glue A: 2 kg of deionized water is added into 2-3 kg of the polytetrafluoroethylene emulsion, and the mixture is uniformly mixed for later use;

and (3) glue B: slowly adding 1-2 kg of battery-grade lithium hydroxide into 5 kg of deionized water, continuously stirring until the lithium hydroxide is completely dissolved, slowly adding 7-8 kg of electronic glue into the deionized water, and continuously stirring for 20 minutes for later use;

3) adding glue into the powder:

adding 120 kg of manganese dioxide, 5 kg of acetylene black and 10 kg of graphite powder into a high-speed stirrer, covering a cover, and stirring for 3 minutes; connecting a high-speed stirrer and a glue injection machine through a pipeline, arranging a spray pipe in the high-speed stirrer, spraying glue added in the glue injection machine into the high-speed stirrer by using high-pressure air, adding glue A into the glue injection machine, stirring while spraying, continuing for 20 minutes, adding glue B into the glue injection machine, stirring while spraying, continuing for 20 minutes; after stirring, filling the mixed powder into a blanking basin through a discharge hole;

4) stirring and mixing:

adding the mixed powder in the blanking basin into a groove-type stirrer, stirring for 30 minutes, barreling, sealing and curing for 24 hours after the stirring is finished, so that the wetting property of the glue is better;

5) powder pressing:

adding the cured mixed powder into a hopper of a powder pressing machine, extruding the mixed powder, and dropping the extruded mixed powder into a material receiving basin;

6) swing granulation of granules:

adding the blocky mixed powder into a swing granulator and stirring, mounting a stainless steel mesh on the swing granulator, continuously rolling and stirring the mixed powder in the granulator, extruding and crushing large particles into small particles, allowing the small particles to pass through the stainless steel mesh, and allowing the large particles to fall into a material receiving basin completely after stirring;

7) powder sieving:

after granulation is finished, adding the mixed powder into a linear vibrating screen, wherein a screen mesh is additionally arranged on the linear vibrating screen, the mixed powder is added from one end of the vibrating screen, and falls down from a discharge port at the other end through vibrating by passing through the screen mesh, the number of the discharge ports is two, and a discharge port A is arranged at the upper part of the screen mesh, so that finished powder is screened out; the lower part of the screen is a discharge hole B which is a defective product;

8) pressing a positive plate:

during adding the hopper of full-automatic tablet press with finished product powder, through the pipeline, fill in cylindrical silo, carry out the pre-compaction for the first time, install the die-cut structure of current collecting net on the tablet press additional, the pre-compaction is accomplished the back, by the die-cut diameter of die-cut structure and the unanimous stainless steel mesh piece of circular silo, during direct die-cut entering circular silo carries out the shaping suppression for the second time again.

2. The method as claimed in claim 1, wherein the trough mixer has a horizontal serpentine paddle, and the mixing process continuously extrudes and kneads the powder, so that the glue is more uniformly coated on the surface of the powder particles, thereby tightly bonding the three powder materials together.

3. The manufacturing method of the storage-resistant lithium-manganese battery anode according to claim 1, wherein the powder pressing machine comprises two pressing rollers which are arranged side by side from left to right, the distance between the two pressing rollers is 2mm, ten grooves with the width of 10mm and the depth of 3mm are uniformly distributed on each pressing roller, the hopper is positioned above the two pressing rollers, the mixed powder in the hopper falls between the pressing rollers, the two pressing rollers rotate inwards in opposite directions, and the mixed powder forms a block with the thickness of 2mm after being extruded.

4. The method of claim 1, wherein the lower punch has a groove with a trapezoidal cross section on its surface inside the circular trough. Depth 1mm, angle 45.

5. The method for manufacturing the storage-resistant lithium-manganese battery positive electrode according to claim 1, wherein a 50-mesh stainless steel net is mounted on the rocking granule machine.

6. The method of claim 1, wherein a 60-mesh screen is added on the linear vibrating screen.

7. The storage-resistant lithium-manganese battery positive electrode one-step forming equipment of claim 1, which comprises a full-automatic tablet press, a hopper, a feeding station, a prepressing station, a current collecting net punching station, a second press, a forming station, a rotary conveying rail, a stainless steel mesh belt conveying rail and a stainless steel mesh belt bracket, wherein the hopper is arranged on the full-automatic tablet press;

the rotary conveying track is provided with a plurality of material troughs, the hoppers, a feeding station, a prepressing station and a current collecting net punching station, forming stations are sequentially arranged on the rotary conveying track, the second press is arranged at the current collecting net punching station, and the stainless steel mesh belt conveying track passes through the current collecting net punching station;

the surface of the lower punch in the trough is provided with an inner chamfer with the depth of 1mm and the angle of 45 degrees.

Technical Field

The invention relates to a method for manufacturing a storage-resistant lithium-manganese battery anode, and belongs to the technical field of lithium-manganese batteries.

Background

A button cell of Li-Mn dioxide is a kind of primary cell which uses metal Li as negative pole, Mn dioxide as positive pole and uses button shape to carry out encapsulation. Compared with other lithium batteries, the lithium battery has relatively low material and manufacturing cost and good safety, and is one of the most widely used commercial lithium batteries. Lithium manganese button cells, while reaching high levels of power performance and capacity, have many problems with storage life. The first direction of the storage-resistant battery is to remove water and free hydrogen ions in the positive plate, so as to avoid the side reaction between the water and the metal lithium cathode in the battery system,

currently, Electrolytic Manganese Dioxide (EMD) is mostly adopted as a positive electrode material of the lithium manganese battery, and the general EMD contains quite a lot of alpha-MnO 2 and gamma-MnO 2 and a small amount of water. In the anode material of the lithium manganese dioxide button cell, the performance of alpha-Mn 02 is the worst, gamma-MnO 2 containing a small amount of moisture is poorer, and gamma/beta mixed crystal form-MnO 2 and beta-MnO 2 without crystal water are more ideal forms. In the industry, a calcination method (330-.

Disclosure of Invention

The invention aims to overcome the defects in the background technology and provide a manufacturing method of a storage-resistant lithium-manganese dioxide button cell positive electrode.

The invention is realized by the following technical scheme:

a method for manufacturing a storage-resistant lithium-manganese battery anode comprises the following steps;

1. pretreatment of manganese dioxide:

and pouring manganese dioxide powder into a tray, leveling the surface of the powder by using a height limiting tool, and simultaneously enabling the powder to be consistent in height and 30-33mm in height. And (3) placing the tray into a side heating blast oven to ensure the temperature uniformity in the oven, and starting timing to continuously bake for 20 hours after the temperature reaches 380-400 ℃.

2. Preparing an adhesive:

glue A: 2 kg of deionized water is added into 2-3 kg of the polytetrafluoroethylene emulsion, and the mixture is uniformly mixed for later use.

And (3) glue B: slowly adding 1-2 kg of battery-grade lithium hydroxide into 5 kg of deionized water, continuously stirring until the lithium hydroxide is completely dissolved, slowly adding 7-8 kg of electronic glue into the mixture, and continuously stirring for 20 minutes for later use.

3. Adding glue into the powder:

adding 120 kg of manganese dioxide, 5 kg of acetylene black and 10 kg of graphite powder into a high-speed stirrer, covering a cover, and stirring for 3 minutes. The high-speed stirring machine is connected with the glue injection machine through a pipeline, a spray pipe is arranged in the high-speed stirring machine, the glue added in the glue injection machine is sprayed into the high-speed stirring machine through high-pressure air, the glue A is added into the glue injection machine, the spraying and stirring are carried out while continuing for 20 minutes, the glue B is added into the glue injection machine, the spraying and stirring are carried out while continuing for 20 minutes. After stirring, the mixed powder is put into a blanking basin through a discharge hole.

4. Stirring and mixing:

mix the powder in the blanking basin, add the cell type mixer in, there is a horizontal snakelike stirring rake of a pair in the cell type mixer, the stirring process constantly extrudees the powder and kneads for the cladding that glue is more even is on powder granule surface, closely bonds three kinds of powder materials together, stirs 30 minutes, and the sealed curing of barrelling after the completion is 24 hours, makes the glue infiltration nature better.

5. Powder pressing:

and adding the cured mixed powder into a hopper of a powder pressing machine. The powder pressing machine consists of two left and right parallel pressing rollers, the distance between the two pressing rollers is 2mm, and ten grooves with the width of 10mm and the depth of 3mm are uniformly distributed on each pressing roller. The hopper is located two compression roller tops, and the mixed powder in the hopper falls into between the compression roller, and two opposite direction internal rotation of compression roller extrude mixed powder, and the fluting is favorable to mixed powder to pass through sooner. The mixed powder is extruded to form a block with the thickness of 2mm and falls into a material receiving basin.

6. Swing granulation of granules:

the blocky mixed powder is added into the swing granulator to be stirred, the 50-mesh stainless steel net is installed on the swing granulator, the mixed powder is continuously rolled and stirred in the granulator, large particles are extruded and crushed into small particles, the small particles penetrate through the 50-mesh stainless steel net, and the mixed powder falls into a material receiving basin completely after being stirred.

7. Powder sieving:

after granulation is finished, adding the mixed powder into a linear vibrating screen, wherein a 60-mesh screen is additionally arranged on the linear vibrating screen, the mixed powder is added from one end of the vibrating screen, and falls down from a discharge port at the other end through vibration of the screen, wherein two discharge ports are arranged, and a discharge port A is arranged at the upper part of the screen, so that finished powder is screened out; the lower part of the screen is a discharge hole B which is a defective product.

8. Pressing a positive plate:

adopting one-step forming equipment, comprising a full-automatic tablet press, a hopper, a feeding station, a pre-pressing station, a current collecting net punching station, a second press, a forming station, a rotary material conveying rail, a stainless steel mesh belt conveying rail and a stainless steel mesh belt bracket;

the rotary conveying track is provided with a plurality of material troughs, the hoppers, a feeding station, a prepressing station and a current collecting net punching station, forming stations are sequentially arranged on the rotary conveying track, the second press is arranged at the current collecting net punching station, and the stainless steel mesh belt conveying track passes through the current collecting net punching station;

adding finished product powder into a hopper of a full-automatic tablet press, filling a material groove of a rotary material conveying rail into a material loading station through a pipeline, carrying the material groove to a pre-pressing station by the rotary material conveying rail to carry out first pre-pressing, carrying the pre-pressed material groove to a current collecting net punching station by the rotary material conveying rail after the pre-pressing is finished, carrying out the press-fitting of a stainless current collecting net by a second press, and carrying out the second forming and pressing on the material groove with the press-fitted stainless current collecting net by the rotary material conveying rail to a forming station.

The surface of the lower punch in the trough is provided with an inner chamfer with the depth of 1mm and the angle of 45 degrees.

The invention has the following beneficial effects:

(1) the manganese dioxide is pretreated by a novel calcination method, and is converted into a mixed crystal form mainly containing beta-MnO 2 without crystal water and a small amount of gamma-MnO 2 as an auxiliary after calcination, so that most of crystal water in EMD is removed, and the generation of side reactions in a battery is reduced.

In the prior art, PTFE emulsion is singly used as a binder, acetylene black is used as a conductive agent, N-methyl pyrrolidone or isopropanol is added, and mixed powder is prepared into paste. The PTFE emulsion is polytetrafluoroethylene dispersion liquid with solid content of about 60 percent. After the PTFE emulsion and the active material are mixed and dried, the PTFE can be used for coating active material particles in a net structure and mutually connecting the active material particles for achieving the adhesion purpose. And the polytetrafluoroethylene is an insulator per se, so that the internal resistance of the battery is increased. Acetylene black, as a single conductive agent, is not in close contact with active substances, so that the ion migration speed is reduced, and the internal resistance of the battery is increased. Due to the limitation of an EMD production process, the material is slightly acidic, so that the positive plate contains free hydrogen ions, and the free hydrogen ions and the metal lithium generate side reaction in a battery system, thereby influencing the storage life of the battery.

(2) The proportion of deionized water is small, so that the water residue is reduced; and lithium hydroxide as an additive is dissolved in the electronic glue to prepare glue B, and the glue B is added into the stirrer after the glue A, so that the failure of the glue A is avoided. The addition of the lithium hydroxide can neutralize hydrogen ions in the battery system and bring no new impurities to the battery system, thereby greatly reducing the side reaction of the battery. Compared with wet tabletting by using N-methyl pyrrolidone or isopropanol, the method has the advantages of greenness, environmental protection and safety. The polytetrafluoroethylene is not conductive and nonvolatile, and influences the conductivity and the liquid absorption of the anode. The addition of the electronic glue reduces the usage amount of polytetrafluoroethylene, and meanwhile, when the positive plate is baked at high temperature to remove moisture, the electronic glue can volatilize from the positive plate, so that the liquid absorption amount of the positive plate is increased.

(3) The acetylene black and the graphite powder are both granular conductive agents, but the particle diameters of the acetylene black and the graphite powder just form a state of size complementation. And the spraying type glue injection ensures that the glue and the powder are more uniform.

(4) The horizontal snake-shaped stirring paddle is used for stirring and mixing, so that the polytetrafluoroethylene can be rapidly connected into a net in an adhesive mode, and a bonding effect is achieved. After stirring, the curing process is sealed, so that the PTFE self-crosslinking is more sufficient, and the bonding requirement can be met by a small amount of proportioning.

(5) The grooves are formed in the compression roller, so that the mixed powder can pass through gaps more quickly, heat can be generated during rolling, the water content in the mixed powder is further reduced, and the storage life of the battery is prolonged.

(6) The granulation screening powder can enable the material of the finished powder to be more uniform, and the consistency of the anode finished product is ensured. The finished powder with the particle size of more than 60 meshes is selected, the compacted density of the powder is higher, the cohesive force among the components is stronger, and the internal resistance is further reduced. Meanwhile, the powder is more uniform, the particle mobility is better, the flow in the pipeline is smoother, and the consistency of the prepared finished product is better.

(7) The lower punch of the trough is provided with an inner chamfer with the depth of 1mm and the angle of 45 degrees, so that after the positive plate is formed, a chamfer exists on the edge of the black powder, and the edge of the positive plate is not easy to damage. The current collecting net punching structure additionally arranged enables the positive plate to be formed at one time, and greatly improves the productivity.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic view of a one-shot molding apparatus;

1-a rotary conveying track of a full-automatic tablet press, 2-a trough, 3-a loading station, 4-a hopper, 5-a prepressing station of the full-automatic tablet press, 6-a stainless steel mesh belt, 7-a stainless steel conveyer belt roller, 8-a second press, 9-a stainless steel mesh support, 10-a collector net punching station and 11-a forming station;

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A method for manufacturing a storage-resistant lithium-manganese battery anode comprises the following steps;

1. pretreatment of manganese dioxide:

and pouring manganese dioxide powder into a tray, leveling the surface of the powder by using a height limiting tool, and ensuring the powder to have consistent height and 30-33mm height so as to ensure the uniformity of the heated powder. And (3) placing the tray into a side heating blast oven to ensure the temperature uniformity in the oven, and starting timing to continuously bake for 20 hours after the temperature reaches 380-400 ℃.

2. Preparing an adhesive:

glue A: 2 kg of deionized water is added into 2-3 kg of the polytetrafluoroethylene emulsion, and the mixture is uniformly mixed for later use.

And (3) glue B: slowly adding 1-2 kg of battery-grade lithium hydroxide into 5 kg of deionized water, continuously stirring until the lithium hydroxide is completely dissolved, slowly adding 7-8 kg of electronic glue into the mixture, and continuously stirring for 20 minutes for later use.

3. Adding glue into the powder:

adding 120 kg of manganese dioxide, 5 kg of acetylene black and 10 kg of graphite powder into a high-speed stirrer, covering a cover, and stirring for 3 minutes. The high-speed stirring machine is connected with the glue injection machine through a pipeline, a spray pipe is arranged in the high-speed stirring machine, the glue added in the glue injection machine is sprayed into the high-speed stirring machine through high-pressure air, the glue A is added into the glue injection machine, the spraying and stirring are carried out while continuing for 20 minutes, the glue B is added into the glue injection machine, the spraying and stirring are carried out while continuing for 20 minutes. After stirring, the mixed powder is put into a blanking basin through a discharge hole.

4. Stirring and mixing:

mix the powder in the blanking basin, add the cell type mixer in, there is a horizontal snakelike stirring rake of a pair in the cell type mixer, the stirring process constantly extrudees the powder and kneads for the cladding that glue is more even is on powder granule surface, closely bonds three kinds of powder materials together, stirs 30 minutes, and the sealed curing of barrelling after the completion is 24 hours, makes the glue infiltration nature better.

5. Powder pressing:

and adding the cured mixed powder into a hopper of a powder pressing machine. The powder pressing machine consists of two left and right parallel pressing rollers, the distance between the two pressing rollers is 2mm, and ten grooves with the width of 10mm and the depth of 3mm are uniformly distributed on each pressing roller. The hopper is located two compression roller tops, and the mixed powder in the hopper falls into between the compression roller, and two opposite direction internal rotation of compression roller extrude mixed powder, and the fluting is favorable to mixed powder to pass through sooner. The mixed powder is extruded to form blocks with the thickness of 2mm, and the blocks fall into a material receiving basin

6. Swing granulation of granules:

the blocky mixed powder is added into the swing granulator to be stirred, the 50-mesh stainless steel net is installed on the swing granulator, the mixed powder is continuously rolled and stirred in the granulator, large particles are extruded and crushed into small particles, the small particles penetrate through the 50-mesh stainless steel net, and the mixed powder falls into a material receiving basin completely after being stirred.

7. Powder sieving:

after granulation is finished, adding the mixed powder into a linear vibrating screen, wherein a 60-mesh screen is additionally arranged on the linear vibrating screen, the mixed powder is added from one end of the vibrating screen, and falls down from a discharge port at the other end through vibration of the screen, wherein two discharge ports are arranged, and a discharge port A is arranged at the upper part of the screen, so that finished powder is screened out; the lower part of the screen is a discharge hole B which is a defective product.

8. Pressing a positive plate:

adopting one-step forming equipment, and referring to the attached figure 1;

a plurality of material troughs 2, a hopper 4, a feeding station 3, a prepressing station 5 and a current collecting net punching station 10 are arranged on a rotary material conveying rail 1 of the full-automatic tablet press in sequence, a forming station 11 is arranged on the rotary material conveying rail in sequence, a second press 8 is arranged on the current collecting net punching station, and a stainless steel mesh belt conveying rail passes through the current collecting net punching station;

adding finished product powder into a hopper of a full-automatic tablet press, filling a material groove of a rotary material conveying rail into a material loading station through a pipeline, carrying the material groove to a pre-pressing station by the rotary material conveying rail to carry out first pre-pressing, carrying the pre-pressed material groove to a current collecting net punching station by the rotary material conveying rail after the pre-pressing is finished, carrying out the press-fitting of a stainless current collecting net by a second press, and carrying out the second forming and pressing on the material groove with the press-fitted stainless current collecting net by the rotary material conveying rail to a forming station.

The surface of the lower punch in the trough is provided with an inner chamfer with the depth of 1mm and the angle of 45 degrees.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.