KR20200045794A - Lead-acid battery with activated carbon powder additive - Google Patents

Abstract

The present invention relates to a lead acid battery added with an activated carbon powder additive. More specifically, the present invention relates to a lead acid battery added with an activated carbon powder additive. To this end, an activated carbon powder additive is added during a positive electrode active material mixing process to support an active material structure using small porous characteristics. A plurality of pores secure a space in active material particles to allow a larger amount of electrolytic solution to penetrate, causing lead sulfate to react to produce lead oxide and improve basic performance.

Description

Lead-acid battery with activated carbon powder additive

The present invention relates to a lead acid battery in which an activated carbon powder additive is added, and more specifically, by introducing an activated carbon powder additive in a positive electrode active material mixing process, supporting a structure of an active material by using a small porosity characteristic of a small number of pores in the active material particles The present invention relates to a lead acid battery in which an activated carbon powder additive is added to improve the basic performance by securing lead and reacting with lead sulfate to generate lead oxide.

The present invention relates to an active material applied to a negative electrode plate of a lead acid battery and a method of manufacturing the same.

In general, lead acid batteries used in automobiles and the like are secondary batteries capable of charging and discharging.

Dilute sulfuric acid (H2SO4) is used as the electrolyte, and if you connect lead dioxide (PbO2) to the positive electrode (+) and sea level lead (Pb) to the negative electrode (-) as an active material of the electrode plate, connect it to an external circuit. As it flows, the active materials of the positive electrode (+) and the negative electrode (-) change (discharge) to lead sulfate (PbSO4). Conversely, when an electric current flows from the outside, the lead sulfate is again lead dioxide (+) and lead on the sea surface (-) It is to use the principle of change (charge).

Among them, the positive electrode and the negative electrode are made of an active material that generates an electrical signal, and a substrate that supports the passage and active material of the electrical signal, and the performance and capacity of the lead acid battery varies depending on the weight of the active material. Varies with size.

The active material of a conventional lead acid battery is generally based on an aqueous solution of sulfuric acid and sulfuric acid, and other additives are mixed according to the characteristics of the anode and cathode, and then mixed to make an active material.

The active material made in this way is applied to a substrate, and then subjected to a aging process and a drying process according to the positive / negative electrode properties, and then the prepared positive and negative plates are superimposed in alternating sheets, and at this time, to prevent electrical shorts between the electrode plates. In order to install a non-conductive separator, the positive electrode plate, the negative electrode plate, and the separator plate are configured to form a pole plate group.

A number of pole plates are connected in series according to the storage battery capacity, and are accommodated in the rolling tank.

The accommodated electrode plate group is subjected to a supercharged chemical conversion process so as to have electrical properties. At this time, the active material of the positive electrode plate is formed of lead dioxide (PbO2), and due to its characteristics, fine particles of oxidized lead are bound innumerably and particles are rich in porosity. The electrolyte is free to diffuse and penetrate the liver. In addition, the active material of the negative electrode plate is spongy lead (海綿 狀 鉛, Pb), which is also rich in porosity and reactivity, allowing the electrolyte to diffuse and penetrate freely.

Products made in this way can only be used in the market.

Among the above processes, the super-charging process is smoothly performed, and a separate aging and drying process is performed for each polarity in order to improve the durability of the product.

The aging process of the positive electrode plate is an important process to increase the durability of the product, and lead (Pb), which is a component of the active material, is supplied with lead oxide (Pb) as the hot temperature (about 70 to 100 ° C) of steam and moisture (at least 99% humidity). PbO) as well as the crystal structure of the active material.

The cathode plate can be aged and dried at the same time if left in a natural state without a separate process.

However, if sufficient maturation and drying are not achieved, the electrode plates and the electrode plates stick together in the assembly process of forming the electrode plate group, and moisture is present, so the durability of the active material is reduced and the active material embedded between the substrates is easily dropped even with a small impact.

As the number of charge and discharge increases, the lead-acid battery made through this process is more likely to fall off the substrate by the reaction of lead and sulfuric acid, and the fallen active materials can no longer participate in the reaction. By reducing the performance, the lead-acid battery's lifespan is usually only 1 to 2 years.

In order to facilitate supercharging of the product, product durability is deteriorated unless sufficient aging and drying are performed on the negative electrode plate. This is because the negative electrode plate is naturally aged and dried, but contains moisture in the prepared electrode plate.

Prior documents related to the present invention include 'Patent Document 1', 'Patent Document 2', and 'Patent Document 3'.

Patent Document 1 relates to a method of synthesizing nano-sized silicon particles by ultrasonic treatment of porous silicon particles.

Silicon is a material that can replace the carbon material as a negative electrode material for a lithium secondary battery.

In the case of the currently commercialized graphite material, the theoretical capacity is 372 mAh / g, but the silicon has a theoretical capacity of 4000 mAh / g or more.

However, in the case of silicon, the electrode undergoes many volume changes (310%) in the process of alloying / dealloying with lithium, and thus the electrode is deteriorated. Has solved this problem.

Patent Literature 2 contains diatomaceous earth and carbon in an active material raw material mainly composed of a metal oxide for a secondary battery, or contains diatomaceous earth, and the content of carbon is minus 4.6 x 10-1 multiplied by the content of diatomaceous earth to 4.9. It contains the value indicated by the straight line drawn by the function represented by the linear equation that adds, and does not contain the carbon content and "0", including "0", which is also determined for the range of values beyond the value indicated by the straight line. It relates to a negative electrode composition for a secondary battery, characterized in that the value "S" of the mass of diatomaceous earth is made from a mixture containing at least "S / Ax100" mass percent relative to the mass "A" of the active material raw material. .

As a conventional technique, Patent Literature 3, Patent No. 10-0483246 discloses a technology for a negative electrode active material characterized in that 'cathode active material and its manufacturing method and lead acid battery' are made by adding lignin to lead powder. have. However, the above technique can expect an effect of improving the life of the active material, but it was difficult to expect an effect of increasing the surface area and increasing the permeability of the electrolyte.

However, the problems of the prior art,

Although it is possible to improve the temporary product performance by improving the electrode of the lead acid battery, it was not a technology that can specifically increase the reaction area between the positive electrode active material and the electrolyte and provide basic performance and durability.

Republic of Korea Patent Publication No. 10-2004-0082876 (September 30, 2004) Japanese Patent Publication No. 2010-225564 (October 7, 2010) Korea Registered Patent 10-0483246 (May 16, 2002)

An object of the present invention is to provide a lead acid battery in which an activated carbon powder additive is added in order to improve the basic performance and durability of the lead acid battery.

Another object of the present invention is to provide a lead acid battery in which an active carbon powder additive having improved basic performance is increased by increasing a reaction area between an active material and an electrolyte during charging and discharging.

The present invention has been devised to supplement the above-described problems and to achieve the object.

Crushing wood (S100); and

Carbide manufacturing step (S200); and

Chemical treatment step (S300); and

Activated carbon cleaning step (S400); and

Activated carbon drying step (S500);

It is intended to provide a lead acid battery in which an activated carbon powder additive is added, characterized in that it is added after mixing with other additives at a ratio of 1 to 3 parts by weight of the activated carbon compared to 100 parts by weight of the powder.

The lead acid battery in which the activated carbon powder additive according to the present invention is added has improved basic performance and durability compared to a conventional lead acid battery.

1 is a photograph of pores formed in the wood flour.
2 is an embodiment of the activated carbon production step.
3 is a modeling diagram in which the electrolyte contacts the active material through the pores of the wood flour.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is an embodiment of the activated carbon production step.

1) Preparation of activated carbon using wood

Refers to the powder crushed by carbonizing wood at a temperature of 600 to 900 ° C. The crystal structure is amorphous and has a wide specific surface area because it has various sizes of pores.

The main raw materials used are oak, bamboo, and coconut.

(A) crushing wood (S100);

Wood may be finely divided before carbonization heat treatment, and this fine powder is crushed by a ball mill that crushes raw materials by putting wood into a rotating cylinder, and a hammer mill that is crushed by a plurality of hammers attached to a rotating shaft. , It can be performed by a method of a jet mill using an attrition mill and air flow to pulverize by rotating at a high speed with a ball.

It can be finely divided to a particle size (average particle size) of 0.01 to 0.6mm by grinding. By performing the carbonization heat treatment (b) and chemical activation treatment (c) of the finely divided wood powder to a particle size of 0.01 to 0.6 mm, pores of an open structure are formed homogeneously in the activated carbon to improve the specific surface area of the activated carbon.

(b) preparing a carbide by heat-treating the crushed wood (wood flour) in an inert atmosphere at 600 to 900 ° C. for 1 to 3 hours; (Carbide production step (S200));

The inert atmosphere at the time of carbonization heat treatment may mean an inert gas atmosphere, and the inert gas may include nitrogen, argon or a mixed gas thereof.

The inert atmosphere may be an atmosphere in which an inert gas flows at 100-1000 cc / min.

By performing carbonization heat treatment in an atmosphere in which an inert gas flows at 100-1000 cc / min, the gaseous product generated during heat treatment can be removed to carbonize wood powder more quickly, and oxidation by oxygen can be minimized.

The carbonization heat treatment may be performed at a temperature of 600 to 900 ° C. When the temperature is less than 600 ° C, the heat treatment is not properly performed, so the increase in physical properties is not high, and at a temperature exceeding 900 ° C, the wood powder is oxidized to reduce the final yield. However, excessive increase in production cost due to high temperature heat treatment may occur.

The time at which the carbonization heat treatment is performed may be sufficient as long as sufficient carbonization of wood powder occurs.

Carbonization heat treatment may be performed for 1 hour to 3 hours.

(c) a chemical treatment step of reacting NaOH with the carbide (carbonized wood powder) at a reaction temperature of 730 ° C. for 60 minutes; (Chemical treatment step (S300));

Chemical activation is a method of producing porous activated carbon having fine pores by dehydrating and oxidizing reaction of chemicals by heating by depositing an activator, which is a chemical, to raw materials and carbides (carbonized wood powder) to be produced from activated carbon, unlike physical activation. to be.

In the chemical activation process, the activation temperature is a very important factor and may affect the formation and adsorption performance of the pore structure.

In the reaction of NaOH and C, the reaction formula most favorable to the activation condition is as follows.

------- 식1

------- Equation 1

In Equation 1 above, the Gibbsfreeenergy change (ΔG) value has a negative value (ΔG <0) above 730 ℃, so 730 ℃ is set as the reaction temperature.

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(d) activated carbon cleaning step (S400);

Cleaning can be said to be a process for removing activators, gases, metal elements (Na), etc. remaining in the pores and surfaces of activated carbon.

The washing method is neutralized by adding 5M hydrochloric acid equivalent to 10 times the volume of activated carbon to activated carbon and shaking it once to neutralize it, and then adding a distilled water equivalent to 10 times the volume to activated carbon and shaking it with shaking 5 times. How to set

(e) activated carbon drying step (S500);

After washing, it is dried for about 12 hours at a temperature of 105 ± 5 ℃.

The specific surface area (specific surface area, specific surface, specific surface area) in the present invention means a value (cm 2 / g) obtained by dividing the surface area of a material by its weight.

(Example)

Using the activated carbon in the production method as described above,

In order to make four samples, the activated carbon, which is an electrode material, was compared to 100 parts by weight of activated carbon as 0 parts by weight (sample 1), 2 parts by weight (sample 2), 4 parts by weight (sample 3), and 6 parts by weight (sample 4), respectively. After preparing it in a mixer with water and sulfuric acid and other additives, it was collected based on 1 g and the specific surface area was measured by a gas adsorption method using a specific surface area measuring device (trade name: Macsorb1210, manufactured by Mount Tech).

100 parts by weight per year
Weight of activated carbon Sample 1
(0 parts by weight) Sample 2
(2 parts by weight) Sample 3
(4 parts by weight) Sample 4
(6 parts by weight) Specific surface area (㎠ / g) 1298 1346 1355 1367

Referring to Table 1, the specific surface area improvement rates of Samples 2, 3, and 4 compared to Sample 1 correspond to 3.7%, 4.4%, and 5.3%, respectively.

When too much activated carbon is added, the viscosity of the active material decreases, and the possibility of separation from the positive electrode increases.

Therefore, in view of such a point, values between 3% and 4% were considered to be the most appropriate in the present invention.

Therefore, it is judged that 4 parts by weight or more compared to 100 parts by weight of lead is not appropriate.

In the present invention, values between 3% and 4% were considered to be the most appropriate.

Therefore, the range of 1 part by weight to 3 parts by weight compared to 100 parts by weight of lead is most suitable as a mixing ratio of activated carbon.

(Low temperature starting test)

A storage battery was prepared for each sample of the activated carbon and buffered.

After charging is completed, stabilize for more than 24 hours to be -18 ± 1 ° C.

After 10 seconds of discharge at 608 A, discharge at 365 A is continued until the discharge end voltage reaches 6.0 V. The discharge time at this time is compared.

As a result of evaluating the low-temperature starting performance, the discharge voltage was changed over time for each activated carbon content.

After leaving 24Hr in a chamber at -18 ° C, it was discharged for 10 seconds at 608 A, and discharge was performed until 6.0 V reached 365 A, which is 60% of the discharge current, and the results were compared.

Table 2 shows the discharge time to 365A, and it can be seen that the low-temperature start-up characteristics are improved as the content is increased.

The low-temperature starting performance of Case 1 without activated carbon was 130.1 seconds, and Samples 2 to 4 showed a slightly improved result.

Cathode active material sample Sample 1 Sample 2 Sample 3 Sample 4 365 A, 6.0 V arrival time (sec) 130.1 142.5 143.2 144.2

Table 2 is a table showing the discharge time at low temperature start-up for each sample.

Looking at Table 2, it can be seen that as the specific surface area increased, the basic performance also improved.

3 is a modeling diagram in which the electrolyte contacts the active material through the pores of the wood flour.

3, it can be seen that the aqueous sulfuric acid solution flows through the pores.

Among the above-mentioned contents, contents not indicated in the drawings are contents that can be sufficiently understood by those skilled in the art based on the above-described contents and should be included in the rights of the present invention even if not shown in the drawings.

Those skilled in the art to which the present invention pertains as described above may understand that the present invention may be implemented in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplified in all respects and are not limiting.

The scope of the present invention is indicated by the following claims rather than the above detailed description, and all modifications or variations derived from the meaning of the claims and their equivalent concepts should be interpreted to be included in the scope of the present invention. .

S100: Step of crushing wood
S200: carbide manufacturing step
S300: chemical treatment step
S400: activated carbon cleaning step
S500: activated carbon drying step

Claims (6)

A lead acid battery in which an activated carbon powder additive is added, which is added after mixing with other additives at a ratio of 100 parts by weight or more of activated carbon to 1 part by weight.
According to claim 1,
The activated carbon is crushed wood (S100); and
Carbide manufacturing step (S200); and
Chemical treatment step (S300); and
Activated carbon cleaning step (S400); a lead acid battery containing an activated carbon powder additive, characterized in that produced by.
According to claim 1,
The activated carbon is crushed wood (S100); and
Carbide manufacturing step (S200); and
Chemical treatment step (S300); and
Activated carbon cleaning step (S400); and
Activated carbon drying step (S500); a lead acid battery containing an activated carbon powder additive, characterized in that produced by.
According to claim 2,
A lead acid battery in which an activated carbon powder additive is added, characterized in that NaOH and the carbide (carbonized wood powder) are reacted at a reaction temperature of 730 ° C. for 60 minutes in the chemical treatment step.
According to claim 2,
The wood is a lead acid battery containing an activated carbon powder additive, characterized in that the oak, bamboo, coconut.
According to claim 2,
The carbide manufacturing step,
A lead acid battery in which an activated carbon powder additive is added, wherein the crushed wood (wood flour) is heat-treated in an inert atmosphere at 600 to 900 ° C. for 1 to 3 hours to produce carbide.

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