WO2025033610A1 - Heat-treatment discharging method for preventing ignition and fire of lithium ion battery using incombustible powder - Google Patents

Abstract

The present invention relates to a heat-treatment discharging method for preventing ignition and fire of a lithium ion battery using incombustible powder, wherein by comprising: a battery selecting step (S10) in which batteries are collected after use, performance indexes are diagnosed, and batteries having a charging efficiency (SOC) of 80% or less are selected and prepared; a battery cell opening step (S20) in which the outer periphery of a case of a selected battery cell is cut or perforated to form an opening; an incombustible powder mixing step (S30) in which the battery cell having an opening formed and noncombustible powder are introduced into a reactor and mixed; a heat-treatment discharging step (S40) in which the battery cell mixed with noncombustible powder is heat-treated to discharge an electrolyte through the opening while evaporating; an organic matter collecting step (S70) in which the electrolyte gas evaporated in the heat-treatment discharging step (S40) is cooled and collected and organic matter is recovered; an incombustible powder separating step (S80) in which incombustible powder is separated from the battery cell discharged through the heat-treatment discharging step (S40) and a discharged battery is obtained; and an incombustible powder circulating step (S90) in which the separated incombustible powder is fed into the incombustible powder mixing step (S30) and reused, ignition and fire of the battery after use can be prevented and heat-treatment discharge can be safely and efficiently performed.

Description

Method for heat treatment discharge of lithium ion battery to prevent ignition and fire using non-combustible powder

The present invention relates to a method for heat treatment and discharge to prevent ignition and fire of a lithium ion battery using a non-combustible powder, and more specifically, to a method for safely and efficiently performing heat treatment and discharge by differentiating the process of discharging electricity remaining in a used lithium ion battery used in an electric vehicle or energy storage system from the prior art to prevent ignition and fire of a used battery.

In general, lithium-ion batteries are secondary batteries that generate electricity according to the electrical flow of lithium ions moving through the electrolyte between the positive and negative electrodes, and are widely applied to various power devices such as electric vehicles and energy storage systems (ESS).

The battery cell, the smallest unit of a secondary battery, consists of a cathode and anode materials, an electrolyte, and a separator inside the container. The cathode materials are cathode active materials such as nickel, manganese, cobalt, and aluminum, and the anode materials are cathode active materials such as graphite and carbon. The electrolyte is a liquid with ion conductivity, and is composed of lithium salts made of lithium, phosphoric acid, and fluorine, and an organic solvent, and acts as a medium responsible for the movement of lithium ions during the charging and discharging process.

As lithium-ion batteries contain valuable metals such as lithium, nickel, manganese, and cobalt as active materials, the development of recycling technology to recover valuable metals from batteries discarded after use is actively underway.

For example, Korean Patent No. 10-1220149 discloses a method for producing a sulfuric acid solution of a valuable metal from a spent battery pack, including the steps of disassembling a spent battery pack to obtain a battery cell, cutting the battery cell to expose a cathode structure and an anode structure, discharging the battery cell with the cathode structure and the anode structure exposed, crushing and particle-separating at least a portion of the battery cell to recover valuable metals, and leaching valuable metal powder with an acid solution containing a sulfuric acid solution in a reducing atmosphere to obtain a leaching solution.

Meanwhile, used batteries are diagnosed with their usage history and internal performance indicators (SOH, SOC, SOP, etc.) to determine whether they are to be used/processed for reuse or recycling. Used batteries that have not gone through a separate discharge process after battery diagnosis still have residual electrical energy inside them. Therefore, during the recycling process (crushing, sorting, heat treatment, etc.) to process the positive electrode material (LiNixCoyMnz, LiNixCoyAlz, etc.), the negative electrode material (graphite), and some current collectors (aluminum, copper) into black mass, there is a possibility that the battery may ignite due to internal thermal runaway, resulting in a fire.

Therefore, in order to solve this problem, the recycling process of used batteries involves a discharge process to reduce the electrical energy inside the battery. The discharge process includes a method of chemically discharging the battery by immersing it in salt water, and an electrical discharge method of connecting an electric circuit and moving the electrical energy inside the battery to store or remove electricity.

As an example of a known technology, Korean Patent No. 10-2191858 discloses a method for recovering raw materials from a spent lithium-ion battery, including a spent lithium-ion battery brine precipitation step of precipitating a spent lithium-ion battery in a predetermined brine tank, a discharging step of performing the spent lithium-ion battery brine precipitation step for a predetermined process time to discharge the spent lithium-ion battery, a cutting step of cutting the discharged spent lithium-ion battery into a predetermined size using a cutter, a drying step of inserting the spent lithium-ion battery cut into the predetermined size into a dryer and drying it under predetermined drying process conditions, a grinding step of inserting the dried spent lithium-ion battery into a grinder and grinding it, and a sorting step of inserting the powder ground by the grinder into a sorter to sort raw materials such as cobalt (Co), nickel (Ni), manganese (Mn), carbon (C), copper (Cu), and aluminum (Al), which are active materials.

Batteries used in electric vehicles or energy storage systems according to conventional technology undergo structural and chemical changes as they are repeatedly charged and discharged with continuous use, shortening their battery life. In order to recover valuable metals such as Ni, Co, and Li from the batteries to be recycled, they undergo a recycling process such as electrical or chemical discharge, followed by crushing/pulverization and heat treatment.

As described above, conventional discharge processes include a method of chemically discharging a battery by immersing it in salt water, or an electrical discharge method of storing or removing electricity by connecting an electric circuit.

However, in the case of the chemical discharge method, there is a problem that the internal materials of the battery leak into salt water, generating a large amount of wastewater, and if a short circuit occurs internally, combustion of the electrolyte and thermal runaway may begin due to the instantaneous release of electric energy, which may lead to a risk of fire and explosion even underwater.

In addition, in the case of the electric discharge method, there is a problem that the electric energy remaining inside the battery cannot be completely removed due to unbalanced battery discharge during discharge, and a phenomenon in which the voltage is recovered by the recovery phenomenon that returns to a state of chemical equilibrium may occur.

In addition, since the flammable electrolyte inside the battery increases the possibility of ignition, safety cannot be secured, and fire caused by battery ignition not only causes safety accidents, but also causes problems such as releasing harmful gases including _CO2 , _H2 , and HF.

In the present invention, a battery selection step (S10) is provided in which a battery is collected after use, a performance index is diagnosed, and a battery having a charging efficiency (SOC) of 80% or less is selected and prepared.

A battery cell opening step (S20) of forming an opening by cutting or perforating the outer case of the selected battery cell,

A non-combustible powder mixing step (S30) in which a battery cell with the above-mentioned opening formed and a non-combustible powder are introduced into a reactor and mixed,

A heat treatment discharge step (S40) in which the battery cell mixed with the above-mentioned non-combustible powder is heat treated to discharge the electrolyte through the opening while evaporating it,

An organic matter capture step (S70) for cooling and capturing the electrolyte gas evaporated in the above heat treatment discharge step (S40) and recovering the electrolyte and organic matter,

A non-combustible powder separation step (S80) for separating non-combustible powder from a discharged battery cell through the above heat treatment discharge step (S40) and obtaining a discharged battery,

By including a non-combustible powder circulation step (S90) for reusing the separated non-combustible powder by adding it to the non-combustible powder mixing step (S30), it is possible to achieve the purpose of preventing ignition and fire of the battery after use and performing heat treatment discharge safely and efficiently.

The present invention provides a method for preventing ignition and fire of a used battery by differentiating the process of discharging electricity remaining in a used lithium ion battery used in an electric vehicle or energy storage system from the prior art.

The present invention is advantageous in that it significantly reduces the environmental burden caused by the generation of brine waste and efficiently removes remaining electric energy, unlike conventional chemical discharge methods or electrical discharge methods using brine.

In particular, the present invention has the effect of safely and efficiently performing heat treatment discharge by using a non-combustible powder to block the battery and external conditions, prevent the risk of ignition and fire, and at the same time heat-treating and evaporating and recovering the electrolyte, which is a flammable hazardous chemical substance.

In addition, the present invention has the advantage of minimizing the amount of additionally added non-combustible powder by separating the used non-combustible powder and configuring a method for reusing and circulating it, and reducing energy costs in the heat treatment process by using powder heated by heat treatment.

Figure 1 is a schematic process flow diagram of a heat treatment discharge method for preventing ignition and fire of a lithium ion battery using a non-combustible powder according to the present invention.

Figures 2 and 3 are images of embodiments of a heat treatment discharge method for preventing ignition and fire of a lithium ion battery using a non-combustible powder according to the present invention.

Figure 4 is a graph showing the results of measuring the voltage and weight change rate of a battery cell according to the heat treatment time of a heat treatment discharge method for preventing ignition and fire of a lithium ion battery using a non-combustible powder according to the present invention.

It is to be noted that the method for heat treatment and discharge to prevent ignition and fire of a lithium ion battery using a non-combustible powder to which the technology of the present invention is applied relates to a method for safely and efficiently performing heat treatment and discharge to prevent ignition and fire of a battery after use, differentiating the process of discharging electricity remaining in a lithium ion battery after use in an electric vehicle or energy storage system from the conventional chemical or electrical discharge technology.

The method for heat treatment and discharge for preventing ignition and fire of a lithium ion battery using the non-combustible powder of the present invention comprises a battery selection step (S10), a battery cell opening step (S20), a non-combustible powder mixing step (S30), a heat treatment and discharge step (S40), an organic matter capture step (S70), a non-combustible powder separation step (S80), and a non-combustible powder circulation step (S90), and is specifically as follows.

The above battery selection step (S10) is a step for collecting used batteries, diagnosing their performance indicators, and selecting and preparing batteries with a charging efficiency (SOC) of 80% or less.

In the above battery sorting step (S10), batteries that have been given a reuse/recycling grade are sorted based on the battery's usage history after use and battery performance indicators such as SOC (State of Charge), SOH (State of Health), and SOP (State of Power).

The above battery cell opening step (S20) is a step of forming an opening by cutting or perforating the outer surface of the case of the battery cell selected in the above battery selection step (S10).

In the above battery cell opening step (S20), the battery cell case is cut or perforated to form an opening as a passage for evaporation of the electrolyte in the heat treatment discharge step (S40) described later, thereby preventing swelling or explosion of the battery.

In the above battery cell opening step (S20), methods such as Cutting, Punching, and Crushing are applied to create an opening, and an opening is locally formed in a part of the battery cell where the electrode is not placed. This configuration is to minimize the possibility of fire or explosion due to a local short circuit occurring when a tool or fixture comes into contact with the electrode during the work process or an internal short circuit occurring due to pressure applied to the battery, and can be performed in an inert gas atmosphere such as N ₂ or Ar.

The above-mentioned non-combustible powder mixing step (S30) is a step of introducing and mixing a battery cell with the above-mentioned opening formed and a non-combustible powder into a reactor.

The above non-combustible powder mixing step (S30) uses non-combustible and non-conductive powder as a heat transfer medium to prevent ignition and spread of fire for safe battery discharge.

In the above-mentioned non-combustible powder mixing step (S30), non-combustible powder is introduced and mixed with the battery cell, heat is applied to the powder, and heat is transferred to the inside of the battery cell to evaporate the electrolyte and suppress the electrochemical characteristics of the battery, thereby preventing explosion, ignition, and current conduction.

The non-combustible powder introduced in the above non-combustible powder mixing step (S30) should have a particle size range of 10㎛ to 1mm.

When the particle size of the above-mentioned non-combustible powder is 1 mm or more, the particle size is large and the filling density is low when covering the battery cell, so the effect of preventing ignition and fire spread is low. In addition, when the particle size is 500 μm or less, the filling density is too high, which may block and hinder the passage through which the electrolyte evaporates and escapes, or the separation efficiency in the non-combustible powder separation step (S80) described later may be low, so that the remaining powder may act as an impurity in the subsequent recycling process, requiring a separate separation and removal process. Therefore, the non-combustible powder input in the non-combustible powder mixing step (S30) has a particle size of 10 μm to 1 mm, preferably 500 μm to 1 mm.

In the above non-combustible powder mixing step (S30), the non-combustible powder is added in a range of 50 to 300 wt% relative to the weight of a single battery cell, and is mixed by heating at a temperature of 90 to 180°C.

In the above non-combustible powder mixing step (S30), the non-combustible powder is mixed with the battery cell in the heat treatment discharge step (S40) described later through stirring and heating so that the temperature is homogeneously mixed. In order to ensure uniform heat transfer, the non-combustible powder is heated to a temperature of 90 to 180°C, and the temperature is made uniform by direct or indirect means.

In the above-described non-combustible powder mixing step (S30), a non-combustible powder is injected at a certain ratio into the opening of the battery cell formed in the above-described battery cell opening step (S20) to prevent ignition and fire spread that may occur in the heat treatment and discharge step (S40) described later. The injection ratio may vary depending on the type of non-combustible powder used, but the amount is an amount that covers all sides with a possibility of ignition with the non-combustible powder based on a single battery cell and allows the battery cells to be separated without touching each other, and can be in the range of 50 to 300 wt% based on the weight of a single battery cell, and is preferably injected in the range of 80 to 200 wt%.

The non-combustible powder introduced in the above non-combustible powder mixing step (S30) is composed of a single or composite material selected from the group including aluminum oxide powder, magnesium oxide powder, silicon oxide powder, and ceramic powder.

The above heat treatment discharge step (S40) is a step of heat treating a battery cell mixed with the non-combustible powder and discharging it while evaporating the electrolyte through the opening.

In the above heat treatment discharge step (S40), the battery cell that has gone through the non-combustible powder mixing step (S30) is discharged by evaporating the internal electrolyte that increases the possibility of fire and explosion through heat treatment, and the heated electrolyte is evaporated through the opening formed in the battery cell.

The battery cells that have gone through the above-mentioned non-combustible powder mixing step (S30) are continuously transported to the reactor of the above-mentioned heat treatment and discharge step (S40) in the form of a conveyor such as a roll, chain, or belt type. In the heating section of the above-mentioned heat treatment and discharge step (S40), a single or multiple shutter structure is installed to ensure insulation inside the reactor and airtightness of the injected inert gas, and the equipment is configured by controlling the transport speed and distance to secure a heat treatment time for sufficient evaporation of the electrolyte. In addition, a thermometer and an infrared or thermal imaging camera are installed to monitor the internal heating status of the reactor and the battery cells in real time, and a vent line is installed to prevent safety accidents in advance.

In the above heat treatment discharge step (S40), heat treatment discharge is performed by heating for 0.5 to 10 hours in a temperature range of 90 to 180°C under normal pressure conditions.

For reference, the electrolyte typically used in batteries is composed of EC (ethylene carbonate) with a boiling point of approximately 248°C and PC (propylene carbonate) with a boiling point of 242°C as basic solvents, and DMC (dimethyl carbonate) with a boiling point of 91°C, DEC (diethyl carbonate) with a boiling point of 126°C, and EMC (ethyl methyl carbonate) with a boiling point of 107°C as highly volatile auxiliary solvents, and the composition ratio of the electrolyte within the battery cell is around 10% (approximately 8 to 14%).

In the above heat treatment discharge step (S40), if the heat treatment temperature is 180℃ or higher, the thin film-shaped separator may melt and form a fused state while the cathode, separator, and anode materials are laminated inside the battery, and at a higher temperature, the Al, Cu electrode plates and binders such as PVDF may melt, so when fused, they become even more firmly fixed and sealed in a hard form, which makes crushing, grinding, and separation more difficult during the subsequent recycling process.

In addition, in the heat treatment discharge step (S40), if the heat treatment temperature is a low temperature of 90℃ or lower, some of the electrolyte does not evaporate and remains, so the discharge effect is reduced due to residual electric energy, and there is a problem that a long-term heat treatment is required for complete discharge.

Therefore, in the heat treatment discharge step (S40), the heat treatment is performed at a temperature range of 90 to 180°C, preferably 90 to 150°C, and the heat treatment discharge is performed for 0.5 to 10 hours, preferably 1 to 5 hours, to ensure sufficient evaporation of the electrolyte.

In the above heat treatment discharge step (S40), an inert gas is injected into the reactor to prevent fire or explosion and is used as a carrier gas in the organic matter capture step (S70). The inert gas may be an inert gas such as N ₂ or Ar, and the gas injected in the heat treatment discharge step (S40) may form an air current that is transferred to the organic matter capture step (S70) to be described later and may serve as a carrier gas.

Meanwhile, after the heat treatment discharge step (S40), a reduced pressure electrolyte evaporation step (S50) may be performed to additionally recover the electrolyte adsorbed on the non-combustible powder or remaining inside the battery cell by evaporating it under reduced pressure conditions.

In the above-mentioned depressurized electrolyte evaporation step (S50), the process is performed using the residual heat of the non-combustible powder and battery cell that have undergone the above-mentioned heat treatment and discharge step (S40) in a pressure range of -0.1 MPa to -0.01 MPa, more preferably -0.06 MPa to -0.02 MPa.

In the above-mentioned depressurized electrolyte evaporation step (S50), a single or multiple shutter structure is installed to secure a depressurized state, insulation, and airtightness of the injected inert gas. A pressure gauge is installed to monitor the depressurized state of the reactor within the shutter to relieve excessive depressurization, and a vent line is installed to prepare for emergency situations to prevent safety accidents in advance.

After the above heat treatment discharge step (S40) or depressurized electrolyte evaporation step (S50), a fine separation step (S60) is performed to separate and remove non-flammable powder fines and battery-derived particles contained in the evaporated electrolyte gas before transferring to the organic matter capture step (S70) to be described later.

The above-mentioned separation step (S60) separates and removes the electrolyte evaporated in the commercial heat treatment discharge step (S40) or the electrolyte gas evaporated in the depressurized electrolyte evaporation step (S50) by using a predetermined dust separation device based on the size of the particles or the difference in specific gravity due to air flow. The dust separation device may be applied as a single or multiple device such as a cyclone or particle filter.

The non-combustible powder separated in the above-mentioned fine separation step (S60) is transferred to the non-combustible powder separation step (S80) to be described later.

The above organic matter capture step (S70) is a step of cooling and capturing the electrolyte gas evaporated in the heat treatment discharge step (S40) and recovering the electrolyte and organic matter.

In the above organic matter capture step (S70), the evaporated electrolyte in a gaseous state from which dust and particles have been removed through the above fine separation step (S60) is condensed and captured by cooling due to the temperature difference. The pressure during the condensation process is lowered, and the organic matter condensed during this process is stored in a recovery tank.

The above-mentioned non-combustible powder separation step (S80) is a step of separating non-combustible powder from a battery cell discharged through the above-mentioned heat treatment discharge step (S40) and obtaining a discharged battery.

The above-mentioned non-combustible powder separation step (S80) is a step of separating the non-combustible powder and discharged battery cells that have undergone the above-mentioned heat treatment discharge step (S40) or the above-mentioned pressure-reduced electrolyte evaporation step (S50) based on the size difference.

In the above-mentioned non-combustible powder separation step (S80), discharged battery cells and non-combustible powder are transported using a porous or mesh type conveyor, and the non-combustible powder is separated according to particle size by vibration classification or air separation.

The non-combustible powder separated in the above non-combustible powder separation step (S80) is made to have a particle size range of 500㎛ to 1mm and is prepared in the same range as the non-combustible powder introduced in the above non-combustible powder mixing step (S30).

In the above-mentioned non-combustible powder separation step (S80), the battery cell from which the non-combustible powder has been separated is sent to a process for crushing and pulverizing the battery while keeping the voltage at 0.2 V or less, which significantly reduces the risk of fire and explosion.

The above-mentioned non-combustible powder circulation step (S90) is performed so that the non-combustible powder separated in the above-mentioned non-combustible powder separation step (S80) is input into the above-mentioned non-combustible powder mixing step (S30) for reuse.

In the above non-combustible powder circulation step (S90), the non-combustible powder is introduced into the non-combustible powder mixing step (S30) while still having residual heat at a temperature of 50°C to 80°C, thereby reducing the energy used for reheating.

Hereinafter, an embodiment including a lithium ion battery ignition and fire prevention heat treatment discharge method using a non-combustible powder according to the present invention having the configuration described above is configured, and the effects thereof are determined.

(1) First, prepare the battery for use through the battery selection step (S10).

A battery cell is composed of a cathode material (LiNixCoyMnz, LiNixCoyAlz, _LiCoO2 ), an anode material (graphite), a current collector (aluminum, copper), a separator to prevent internal short circuits, an electrolyte that acts as a path for lithium ions, and a binder for adhesion. The representative types of battery cells include pouch type, cylindrical type, and square type.

Used batteries that have been graded for reuse/recycling based on their usage history and condition indicators such as SOC, SOH, and SOP generally contain residual electric energy with an average voltage of approximately 3.0 to 4.0 V per battery cell.

(2) In order to confirm the specifications of the battery cells after the battery selection step (S10), the voltage and weight of the pouch-type battery cells removed from the battery pack installed in the vehicle of Company H were measured, and the measured data is as shown in Table 1 below.

division Initial voltage (V) Initial weight (g) Battery cell 1 3.067 881.1 Battery cell 2 3.082 883.5 Battery cell 3 3.033 881.8 Battery cell 4 3.027 882.6 average 3.052 882.3

As described in Table 1, the initial voltage was 3.052 V on average, with a deviation of ±0.03 V, indicating that there was no significant difference between battery cells. The weight of the battery cells was also confirmed to have little difference, with an average of 882.3±1.03 g. (3) As shown in Fig. 2, in order to allow smooth evaporation of the internal electrolyte in the pouch-type battery cell, approximately 26.5 cm was cut off at both ends of the battery cell (S20), and after going through the non-combustible powder mixing step (S30), heat treatment was performed by injecting _N2 gas at a rate of 40 L/min to create a temperature condition of 150°C at a heating rate of 5°C/min at normal pressure and an inert gas atmosphere (S40). The voltage and weight change rate of the battery cell according to the heat treatment time were measured, and the results are as shown in the graph of Fig. 4.

As shown in the graph of Fig. 4, the weight and voltage showed a tendency to decrease according to the heat treatment time, and it was confirmed that the initial average voltage of the battery cell during the heat treatment rapidly decreased from about 3.052 V to about 2.5 V, and after the heat treatment, the voltage was discharged to 0.141 V, which was a decrease of about 95.4% compared to the initial voltage.

The weight of the battery cell decreased as the heat treatment time increased, and compared to the average initial weight of 882.3 g of the battery cell, it decreased by a total of 83 g to 799.3 g at the end, showing a change rate of approximately 9.4%. There was no additional weight loss after the end point, and the electrolyte composition ratio in the battery cell varied depending on the cell, but was generally similar to 8 to 14%. Based on the results of the experiment, it is believed that the electrolyte evaporated through the low-temperature heat treatment. In addition, the evaporated electrolyte could be recovered through cooling capture (S70).

In addition, when measuring the voltage at room temperature from the time of completion of the normal pressure discharge heat treatment, the voltage decreased continuously, and when measuring the voltage after 24 hours, it decreased slightly to 0.089 V compared to the time of completion of the heat treatment, and the recovery phenomenon that occurs in the conventional electrical discharge was not found, confirming that complete discharge had occurred.

The method for heat treatment and discharge of a lithium ion battery to prevent ignition and fire using a non-combustible powder according to the present invention as described above provides a method for preventing ignition and fire of a battery after use by differentiating the process of discharging electricity remaining in the battery after use from the conventional chemical discharge or electrical discharge technology.

In particular, the present invention has the effect of enabling safer and more efficient heat treatment discharge by using a non-combustible powder to block the battery and external conditions, prevent the risk of ignition and fire, and at the same time heat-treating and evaporating and recovering the electrolyte, which is a flammable hazardous chemical substance.

The present invention has various advantages, such as minimizing the amount of additionally added non-combustible powder by separating the used non-combustible powder and configuring a method for reusing and circulating it, and reducing energy costs in the heat treatment process by using powder heated by heat treatment.

Claims (11)

The battery selection step (S10) is to collect used batteries, diagnose their performance indicators, and select and prepare batteries with a charging efficiency (SOC) of 80% or less. A battery cell opening step (S20) of forming an opening by cutting or perforating the outer case of the selected battery cell, A non-combustible powder mixing step (S30) in which a battery cell with the above-mentioned opening formed and a non-combustible powder are introduced into a reactor and mixed, A heat treatment discharge step (S40) in which the battery cell mixed with the above-mentioned non-combustible powder is heat treated to discharge the electrolyte through the opening while evaporating it, An organic matter capturing step (S70) for cooling and capturing the electrolyte gas evaporated in the above heat treatment discharge step (S40) and recovering the electrolyte and organic matter, A non-combustible powder separation step (S80) for separating non-combustible powder from a discharged battery cell through the above heat treatment discharge step (S40) and obtaining a discharged battery, A lithium ion battery ignition and fire prevention heat treatment discharge method using a non-combustible powder, characterized in that it includes a non-combustible powder circulation step (S90) of introducing the separated non-combustible powder into the non-combustible powder mixing step (S30) and reusing it. In paragraph 1, In the above battery cell opening step (S20), A lithium ion battery ignition and fire prevention heat treatment discharge method using a non-combustible powder, characterized in that an opening is locally formed in a portion of a battery cell where an electrode is not placed to secure a passage for evaporation of an electrolyte. In paragraph 1, A method for heat treatment discharge for preventing ignition and fire of a lithium ion battery using non-combustible powder, characterized in that the non-combustible powder introduced in the above non-combustible powder mixing step (S30) has a particle size range of 10㎛ to 1mm. In paragraph 1, A method for heat treatment discharge for preventing ignition and fire of a lithium ion battery using a non-combustible powder, characterized in that in the non-combustible powder mixing step (S30), the non-combustible powder is added in a range of 50 to 300 wt% relative to the weight of a single battery cell, and is mixed by heating at a temperature of 90 to 180°C. In paragraph 1, A method for heat treatment discharge for preventing ignition and fire of a lithium ion battery using a non-combustible powder, characterized in that the non-combustible powder introduced in the above non-combustible powder mixing step (S30) is composed of a single or composite material selected from the group including aluminum oxide-based powder, magnesium oxide-based powder, silicon oxide-based powder, and ceramic powder. In paragraph 1, In the above heat treatment discharge step (S40), A method for heat treatment discharge for preventing ignition and fire of a lithium ion battery using a non-combustible powder, characterized in that the heat treatment discharge is performed by heating in a temperature range of 90 to 180℃ under normal pressure conditions for 0.5 to 10 hours. In paragraph 1, In the above heat treatment discharge step (S40), A lithium ion battery ignition and fire prevention heat treatment discharge method using a non-combustible powder, characterized in that an inert gas is injected into the inside of a reactor to prevent fire or explosion and is used as a carrier gas in the organic matter capture step (S70). In paragraph 1, After the above heat treatment discharge step (S40), It further includes a depressurized electrolyte evaporation step (S50) for additionally recovering the electrolyte adsorbed on the non-combustible powder or remaining inside the battery cell by evaporating it under reduced pressure conditions. In the above depressurized electrolyte evaporation step (S50), A method for preventing ignition and fire of a lithium ion battery using a non-combustible powder, characterized in that the method is performed by utilizing the residual heat of the non-combustible powder and the battery cell that have undergone the heat treatment discharge step (S40) in a pressure range of -0.1 MPa to -0.01 MPa. In paragraph 1, Before the above organic matter capture step (S70), A method for heat treatment discharge for preventing ignition and fire of a lithium ion battery using a non-combustible powder, characterized in that it further includes a fine separation step (S60) for separating and removing non-combustible powder fines and battery-derived particles contained in evaporated electrolyte gas. In paragraph 1, In the above non-combustible powder separation step (S80), Discharged battery cells and non-combustible powder are transported using a porous or mesh type conveyor, and non-combustible powder is separated by vibration classification or airflow separation. A method for heat treatment discharge for preventing ignition and fire of a lithium ion battery using a non-combustible powder, characterized in that the separated non-combustible powder has a particle size range of 500㎛ to 1mm. In paragraph 1, A method for heat treatment discharge for preventing ignition and fire of a lithium ion battery using a non-combustible powder, characterized in that in the non-combustible powder circulation step (S90), the non-combustible powder is introduced into the non-combustible powder mixing step (S30) while having residual heat at a temperature of 50°C to 80°C.

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