Battery crushing device, crushing method and recycling method

Abstract

The present invention relates to a battery crushing device, crushing method and recycling method. The battery crushing method according to the present invention comprises the steps of: crushing at least one battery; determining, during the crushing, the risk of fire on the basis of the concentration of an electrolyte in the air in a crushing space; and taking a predetermined action for lowering the risk of fire on the basis of the determination of the risk of fire.

Description

Battery crushing device, crushing method, and recycling method

[0001] The present invention relates to battery recycling, and more specifically to an apparatus and method for evaluating and diagnosing safety for recycling batteries.

[0002] In modern society, lithium-ion batteries are widely used in various fields, including eco-friendly vehicles, energy storage systems (ESS), and portable electronic devices. While lithium-ion batteries offer many advantages due to their high energy density and efficiency, they also pose a risk of fire or explosion. In particular, degradation occurring during normal use destabilizes the internal cell structure, which can increase the risk of fire and explosion during the recycling process. Since residual energy may remain within the battery, exposure to environmental factors such as physical impact, high temperatures, or overcharging increases the likelihood of a fire. Therefore, diagnosing and eliminating these fire risks in advance is essential for the safe recycling of batteries.

[0003] In particular, the battery recycling process requires separating or crushing cells. During this stage, rapid chemical reactions can occur within the battery, potentially leading to fires or explosions. Recycling batteries requires devices and systems capable of handling them safely, and specifically, diagnostic technology is needed to conduct the recycling process without the risk of fire. While some diagnostic technologies currently exist, there is still a lack of technology capable of comprehensively diagnosing the thermal and electrical conditions within the battery and identifying abnormalities.

[0004] According to one embodiment of the present invention, the purpose is to prevent the risk of fire that may occur during the crushing process in advance and to extinguish the fire quickly and safely in the event of a fire, thereby enabling the battery recycling process to be carried out safely and efficiently.

[0005] A battery crushing method according to the present invention for the purpose described above comprises: a step of crushing at least one battery; a step of determining a fire risk based on the concentration of electrolyte in the air of the crushing space during the crushing; and a step of taking a predetermined measure to reduce the fire risk based on the determination of the fire risk.

[0006] In addition, when leakage of two or more types of electrolytes is expected in the battery, the fire risk is determined based on the lower of the two or more minimum explosive concentrations (LEL) of each of the minimum explosive concentrations (LEL).

[0007] In addition, the fire risk is determined based on the oxygen concentration of the crushing space along with the minimum explosive concentration (LEL) of the electrolyte.

[0008] Additionally, the method further includes the step of calculating the minimum oxygen concentration (MOC) required for ignition based on the minimum explosive concentration (LEL) of the electrolyte and the oxygen concentration, and determining the fire risk based on the minimum oxygen concentration (MOC).

[0009] In addition, the fire risk is determined by further considering the temperature change spikes that occur when at least one of the batteries is crushed.

[0010] In addition, a predetermined measure to reduce the aforementioned fire risk is to introduce an inert gas into the crushing space.

[0011] In addition, a predetermined measure to reduce the aforementioned fire risk is to lower the oxygen concentration in the crushing space.

[0012] A battery crushing device according to the present invention for the above-described purpose comprises: a crusher configured to crush at least one battery; and a control unit configured to control the crushing process of the at least one battery, wherein the control unit determines a fire risk based on the electrolyte concentration in the air of the crushing space during the crushing; and takes a predetermined measure to reduce the fire risk based on the determination of the fire risk.

[0013] In addition, when leakage of two or more types of electrolytes is expected in the battery, the control unit determines the fire risk based on the lower of the minimum explosive concentrations (LEL) of each of the two or more types of electrolytes.

[0014] In addition, the control unit determines the fire risk based on the oxygen concentration of the crushing space along with the minimum explosive concentration (LEL) of the electrolyte.

[0015] In addition, the control unit calculates the minimum oxygen concentration (MOC) required for ignition based on the minimum explosive concentration (LEL) of the electrolyte and the oxygen concentration; and determines the fire risk based on the minimum oxygen concentration (MOC).

[0016] In addition, the control unit determines the fire risk by further considering the temperature change spike that occurs when the at least one battery is crushed.

[0017] In addition, a predetermined measure to reduce the aforementioned fire risk is to introduce an inert gas into the crushing space.

[0018] In addition, a predetermined measure to reduce the aforementioned fire risk is to lower the oxygen concentration in the crushing space.

[0019] A battery recycling method according to the present invention for the purpose described above comprises: a step of crushing at least one battery; a step of determining a fire risk based on the concentration of electrolyte in the air of the crushing space during the crushing; and a step of taking a predetermined measure to reduce the fire risk based on the determination of the fire risk.

[0020] According to one embodiment of the present invention, the risk of fire that may occur during the crushing process is prevented in advance, and the fire is extinguished quickly and safely in the event of occurrence, thereby enabling the battery recycling process to be carried out safely and efficiently, which can contribute to efficient battery resource circulation in terms of environmental and economic aspects.

[0021] Figure 1 is a diagram showing the battery recycling process.

[0022] FIG. 2 is a diagram showing a control system of a battery crushing process according to one embodiment of the present invention.

[0023] FIG. 3 is a diagram showing a battery crushing control method according to one embodiment of the present invention.

[0024] Figure 4 is a diagram showing thermal images of the battery during room temperature crushing and freezing crushing.

[0025] Figure 5 is a diagram showing the spike shape when the battery is crushed at room temperature.

[0026] Figure 6 is a diagram showing the spike shape during cryogenic crushing of the battery.

[0027] The embodiments described in this document and the configurations illustrated in the drawings are merely preferred examples of the disclosed invention, and various modifications that may replace the embodiments and drawings of this specification may exist at the time of filing this application.

[0028] The terms used in this document are for the purpose of describing embodiments and are not intended to limit or restrict the disclosed invention.

[0029] For example, in this specification, singular expressions may include plural expressions unless the context clearly indicates otherwise.

[0030] In this document, each of the phrases such as "A or B", "at least one of A and B", "at least one of A or B", "A, B or C", "at least one of A, B and C", and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0031] The term "and / or" includes a combination of multiple related described components or any of the multiple related described components. For example, "A and / or B" may include only "A," only "B," or both "A and B."

[0032] Additionally, terms such as “include” or “have” are intended to express the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and do not exclude the additional existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0033] When it is said that a component is “connected,” “combined,” “supported,” or “in contact” with another component, this includes not only cases where the components are directly connected, combined, supported, or in contact, but also cases where they are indirectly connected, combined, supported, or in contact through a third component.

[0034] When it is said that a component is located “on” another component, this includes not only cases where one component is in contact with the other component, but also cases where another component exists between the two components.

[0035] Meanwhile, terms such as “front,” “rear,” “left,” “right,” “top,” and “bottom” used in the following description are defined based on the drawings; however, the shape and position of each component are not limited by these terms. For example, the front side may be defined as the +X side and the rear side as the -X side. For example, based on the drawings, the right side may be defined as the +Y side and the left side as the -Y side. For example, based on the drawings, the top side may be defined as the +Z side and the bottom side as the -Z side.

[0036] In addition, terms including ordinal numbers, such as "first," "second," etc., are used to distinguish one component from another and do not limit the components.

[0037] In addition, terms such as "~part," "~unit," "~block," "~part," and "~module" may refer to a unit that processes at least one function or operation. For example, the terms may refer to at least one piece of hardware such as an FPGA (Field-Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), at least one piece of software stored in memory, or at least one process processed by a processor.

[0038] At least one of the operations to be described below may be performed by a computing device and / or an operator.

[0039] A computing device may include a general-purpose processor such as a CPU, AP, DSP (Digital Signal Processor), a graphics-dedicated processor such as a GPU, VPU (Vision Processing Unit), or an artificial intelligence-dedicated processor such as an NPU.

[0040] A computing device may include a storage medium (e.g., memory) that stores at least one instruction for performing operations to be described below, at least one artificial intelligence model, etc.

[0041] However, at least one instruction and at least one artificial intelligence model may be stored in a separate device outside the computing device (e.g., a cloud computing device), and the operations described below may be performed by a processor included in the separate device outside the computing device (e.g., a cloud computing device).

[0042] A computing device may include an output device (e.g., a display) and / or an input device (e.g., a mouse, a touch panel, etc.) for performing operations to be described below.

[0043] Identical reference numbers or reference symbols presented in the attached drawings may represent parts or components that perform substantially the same function.

[0044] The operating principle and embodiments of the present invention will be described below with reference to the attached drawings.

[0045] Figure 1 is a diagram showing the battery recycling process.

[0046] When a battery's State of Health (SoH) drops below 70%, performance characteristics such as charging speed, output, and duration deteriorate significantly. SoH is a value calculated by comparing the level of performance degradation caused by increased internal resistance to the initial performance. For example, if the capacity at the time of manufacture is 100 and the current effective capacity is 60, the SoH of that battery is 60%.

[0047] Batteries are recycled through reuse or recycling methods depending on their SoH. Batteries with an SoH of 60-70% are reused as energy storage systems (ESS) or uninterruptible power supply (UPS), while batteries with a SoH lower than that are recycled to extract rare metals such as lithium, nickel, cobalt, and manganese, which are then used to manufacture new batteries.

[0048] As shown in FIG. 1, the battery recycling process consists of two stages: a pretreatment process and a posttreatment process. In FIG. 1, reference numerals 110 to 140 represent the pretreatment process, and reference numerals 150 to 180 represent the posttreatment process.

[0049] The pretreatment process includes receiving (110), discharge / deactivation process (120), sorting process after dismantling (130), crushing / grinding process (140), etc.

[0050] In the discharge and deactivation process (120), the risk of explosion is eliminated by forcibly discharging the remaining energy of the battery to deactivate it. Discharge methods include saltwater discharge, electronic load discharge, and dry recovery discharge. Saltwater discharge is a method of discharging by immersing the battery in saltwater and allowing current to flow between the positive and negative electrodes. Electronic load discharge is a method of discharging by applying a load to the battery using a load device with a settable resistance value. The present invention relates to a battery safety diagnosis in an electronic load discharge method discharge process. Dry recovery discharge is a method of recovering and reusing energy consumed during the battery discharge process.

[0051] The sorting process (130) after dismantling is a step of separating the dismantled batteries according to their physical properties by material, generally based on particle size, density, magnetic properties, etc. Through this process, metals such as iron, copper, and aluminum are separated.

[0052] The crushing and grinding process (140) is a process of crushing and grinding batteries to produce black powder, and mainly two methods are used: dry and wet.

[0053] The post-processing process includes a dry process (150) and a wet process (160). The post-processing process is a process of extracting valuable metals such as lithium, nickel, and cobalt by refining the black powder obtained from the pre-processing process. This process is broadly divided into a dry process (150) and a wet process (160). In the dry process (150), the black powder is heated to a high temperature to reduce the metal. In the wet process (160), valuable metals such as lithium, nickel, and cobalt are recovered through processes such as leaching, solvent extraction, and crystallization. The dry process (150) and the wet process (160) can be operated selectively as needed.

[0054] FIG. 2 is a diagram showing a control system for a battery crushing process according to an embodiment of the present invention. The control system for a battery crushing process shown in FIG. 2 focuses on the configuration of a device for detecting a fire risk in advance in the crushing space and responding when a fire risk is detected or when a fire occurs, and the configuration of the device for crushing is simplified to a crusher (232).

[0055] As shown in FIG. 2, a shredder (232) is provided to shred waste batteries during the shredding and crushing process (140) of the battery recycling process. The shredder (232) shreds and crushes batteries during the shredding and crushing process (140) to produce black powder.

[0056] A temperature sensor (234) is provided to detect the temperature within the crushing space where the crushing and grinding process (140) of the battery is performed, the ambient temperature of the battery being crushed, and the temperature of the battery being crushed. The temperature sensor (234) transmits the detected temperature data to the control unit (210), and for this purpose, the temperature sensor (234) is electrically connected to the control unit (210) so as to be able to communicate with it.

[0057] The electrolyte concentration sensor (236) is provided to detect the concentration of electrolyte vapor in the crushing space where the crushing and grinding process (140) of the battery is performed. The electrolyte concentration sensor (236) transmits the detected electrolyte concentration data to the control unit (210), and for this purpose, the electrolyte concentration sensor (236) is electrically connected to the control unit (210) so as to be able to communicate with it.

[0058] An oxygen concentration sensor (238) is provided to detect the oxygen concentration within a crushing space where the crushing and grinding process (140) of the battery is performed. The oxygen concentration sensor (238) transmits the detected oxygen concentration data to a control unit (210), and for this purpose, the oxygen concentration sensor (238) is electrically connected to the control unit (210) so as to be able to communicate with it.

[0059] An inert gas injector (252) is provided to inject (inject) inert gas into the crushing space where the crushing and grinding process (140) of the battery is performed. The injection (injection) of inert gas by the inert gas injector (252) is controlled by a control unit (210), and for this purpose, the inert gas injector (252) is electrically connected to the control unit (210) so as to be able to communicate with it.

[0060] A temperature controller (254) is provided to lower the temperature inside the crushing space where the crushing and grinding process (140) of the battery takes place. The temperature controller (254) may be an air conditioning device or a cooling device. The lowering of the temperature inside the crushing space by the temperature controller (254) is controlled by a control unit (210), and for this purpose, the temperature controller (254) is electrically connected to the control unit (210) so as to be able to communicate with it.

[0061] A fire extinguishing agent sprayer (256) is provided to spray (inject) a fire extinguishing agent for extinguishing fires inside a crushing space where the crushing and grinding process (140) of the battery is performed. The spraying (injection) of the fire extinguishing agent by the fire extinguishing agent sprayer (256) is controlled by a control unit (210), and for this purpose, the fire extinguishing agent sprayer (256) is electrically connected to the control unit (210) so as to be able to communicate with it.

[0062] The control unit (210) can determine the fire risk within the crushing space by directly referencing at least one detection value among the temperature sensor (234), the electrolyte concentration sensor (236), and the oxygen concentration sensor (238). Alternatively, the fire risk within the crushing space can be determined by comprehensively referencing at least one detection value among the temperature sensor (234), the electrolyte concentration sensor (236), and the oxygen concentration sensor (238), along with information such as the Lower Explosive Limit (LEL) and Minimum Oxygen Concentration (MOC) provided in advance for each type of electrolyte.

[0063] Data of the crushing space and LEL data by electrolyte type are input to the control unit (210). The data of the crushing space may be the volume of the crushing space. The data of the crushing space and LEL data by electrolyte type may be provided from a memory (not shown) connected to the control unit (210), or may be input from a manager (operator) through a separate input device (not shown) connected for communication.

[0064] The control unit (210) can take measures to reduce or eliminate the risk of fire within the crushing space using an inert gas injector (252) or a temperature controller (254). Additionally, if a fire occurs, the control unit (210) can take measures to extinguish the fire using a fire extinguishing agent injector (256).

[0065] The control unit (210) may be a processor capable of executing software or firmware for performing the method according to the present invention.

[0066] FIG. 3 is a diagram illustrating a battery shredding control method according to an embodiment of the present invention. The battery shredding control method shown in FIG. 3 can be implemented based on the device configuration shown in FIG. 2.

[0067] When the discharge and deactivation process (120) is completed for a battery determined to be recycled, the crushing and grinding process (140) follows (302). In the crushing and grinding process (140), the battery is disassembled to separate internal materials, and metals and useful materials are recovered through crushing and grinding. In this process, the battery is crushed and ground into small pieces by physical force.

[0068] While the battery is being crushed and ground, the control unit (210) monitors the risk of fire caused by the crushing and grinding of the battery within the crushing process (304). As the battery is crushed, the electrolyte inside the battery leaks out and evaporates, causing electrolyte vapor to accumulate within the crushing space. Since ignition in this state could potentially lead to a fire, the control unit (210) continuously monitors the risk of fire within the crushing space.

[0069] In an embodiment of the present invention, monitoring of fire risk by the control unit (210) is performed as follows. Due to the volatile nature of the electrolyte, which is one of the components constituting the battery, there is a risk of fire during the battery crushing process. The fire risk according to the concentration of the electrolyte and the ambient temperature within the crushing space during the crushing process can be confirmed (evaluated) in the following way.

[0070] To assess the temperature at which a fire may occur, the point where the concentration of the electrolyte in the space exceeds the Lower Explosive Limit (LEL) is identified. The LEL refers to the minimum concentration at which a flammable material can cause an explosion (fire) in air when exposed to an ignition source. The method for calculating the temperature at which the electrolyte concentration reaches the LEL is as follows.

[0071] The following are the minimum explosive concentrations (LEL) for several representative types of electrolytes.

[0072] DMC (Dimethyl Carbonate): approximately 3.22%

[0073] DEC (Diethyl Carbonate): approximately 1.35%

[0074] EMC (Ethyl Methyl Carbonate): approximately 1.7%

[0075] To determine how the electrolyte concentration changes with temperature, the ideal gas law is used to calculate the molarity C(T) of the electrolyte as follows.

[0076] (Equation 1)

[0077] Here, C(T) is the molar concentration of the electrolyte at temperature T (mol / m²) 3 ) and, P electrolyte (T) is the vapor pressure of the electrolyte at temperature T, and V is the volume of the fracture space (0.027 m²) 3 ) and R is the gas constant (8.314 J / (mol·K)).

[0078] To find the temperature at which the molar concentration of the electrolyte reaches the lowest explosive concentration (LEL), the vapor pressure P of the electrolyte electrolyte Calculate the temperature at which the electrolyte concentration exceeds the minimum explosive concentration (LEL) as (T) increases.

[0079] The following is the process of calculating the temperature at which the Minimum Explosive Level (LEL) is reached, using Dimethyl Carbonate (DMC), one of the representative electrolytes, as an example. The LEL of DMC is 3.22%, and the LEL corresponding to the molar concentration is C. LEL It is as follows.

[0080] (Equation 2)

[0081] Here, n airis the number of moles in air, approximately 44.6 mol / m³ 3 Assuming, the vapor pressure P of the electrolyte electrolyte Assuming that (T) increases exponentially with temperature, we find the point at which the minimum explosive concentration (LEL) is reached as the temperature increases.

[0082] This formula can be used to calculate the temperature at which the electrolyte reaches the minimum explosive concentration (LEL). Through this method of calculation, the minimum temperature at which a fire risk occurs for each electrolyte is determined. In the case of DMC, the temperature at which the minimum explosive concentration (LEL) is reached is approximately 60°C.

[0083] For combustion to occur, three elements are required: fuel, oxygen, and an ignition source. In the case of the present invention, the fuel is the electrolyte vapor within the crushing space, the oxygen is the oxygen in the air within the crushing space, and the ignition source is a flame or heat that may be generated during the crushing process. The Minimum Oxygen Concentration (MOC) is the minimum value of oxygen concentration required for ignition, i.e., for a fire or explosion to occur. The Minimum Oxygen Concentration (MOC) can be calculated as a specific value that varies depending on the type and concentration of the fuel (electrolyte vapor).

[0084] The minimum oxygen concentration (MOC) can be calculated as follows.

[0085] (Equation 3)

[0086] Here, LEL is the Lower Explosive Limit of the substance, and O2 concentration is the oxygen concentration in the air, which is 21%. Since the Minimum Oxygen Concentration (MOC) varies for each substance, the value is calculated for each of the various types of electrolytes through experimental data and theoretical calculations.

[0087] For example, if the minimum explosive concentration (LEL) of DMC, one of the representative electrolytes, is 3.22%, the minimum oxygen concentration (MOC) required for DMC to burn is as follows.

[0088] (Equation 4)

[0089] This value represents the oxygen concentration required for combustion, meaning that DMC burns when the oxygen concentration is 0.6762% or higher. In other words, if the oxygen concentration is less than 0.6762%, combustion of DMC does not occur, and therefore, it can be expected that no fire will occur. Conversely, if the oxygen concentration is 0.6762% or higher, combustion of DMC may occur, which can lead to a fire. The same calculation can be performed for each of the various types of electrolytes, and among them, the electrolyte with the lowest minimum oxygen concentration (MOC), that is, the electrolyte with the highest potential for combustion, can serve as the criterion for determining the overall potential for combustion within the fracture space.

[0090] Temperature spikes resulting from friction or impact during battery crushing can act as ignition sources, which are one of the causes of fire. Fig. 4 shows thermal images of a battery during room temperature crushing and cryogenic crushing. In Fig. 4, reference numeral 402 is a thermal image during room temperature crushing and reference numeral 404 is a thermal image during cryogenic crushing. Fig. 5 shows various spike shapes during the battery during room temperature crushing. Fig. 6 shows various spike shapes during the battery during cryogenic crushing. In Figs. 4 to 6, when measuring the temperature of the battery being crushed in the case of room temperature crushing, an instantaneous peak temperature is observed in the range of 60 to 80°C, and after the peak occurs, the temperature shows a pattern of decreasing relatively slowly in conjunction with a chemical reaction. In the case of cryogenic crushing, the peak temperature range is relatively low at 50°C or lower, and only an instantaneous peak is observed; it does not decrease slowly as in the case of room temperature crushing. Since the peak temperature generated during such battery crushing can act as an ignition source, the temperature of the battery being crushed or the ambient temperature of the battery can be monitored by considering the peak temperature characteristics of the batteries during room temperature crushing and cryogenic crushing, respectively, as one of the conditions for determining the fire risk in the battery crushing process.

[0091] Returning to Fig. 2, if a fire risk is identified (e.g., 306), the control unit (210) implements fire prevention measures (308) to reduce or eliminate the fire risk. The fire prevention measures may include, for example, injecting an inert gas into the crushing space when a fire risk is identified, or forcibly lowering the temperature within the crushing space to a temperature below the minimum explosive concentration (LEL).

[0092] When a fire is anticipated during the battery crushing process, the introduction of inert gas can be considered as a method to prevent the fire in advance or to extinguish it after it occurs. Inert gases generally do not react with oxygen, possessing the property of suppressing fire. Representative examples of commonly used inert gases include nitrogen (N2) and carbon dioxide (CO2).

[0093] Nitrogen (N2) does not react with oxygen and makes up about 78% of the air, but fire can be prevented by introducing it into a sealed space at a high concentration to lower the oxygen concentration. Nitrogen can be introduced into the battery crushing process in a gaseous state to prevent fire. By constructing a pipeline or piping system to supply nitrogen within the process, nitrogen is injected directly into high-risk areas, namely the place where battery crushing actually takes place, thereby lowering the oxygen concentration around the battery being crushed when a fire is expected to occur, thus preventing fire.

[0094] Carbon dioxide (CO2) replaces oxygen to induce incomplete combustion and has the effect of inhibiting combustion reactions. As an inert gas, carbon dioxide can be used for both fire suppression and fire prevention. Carbon dioxide is stored in liquid form under high pressure and can be injected in gaseous form into spaces where crushing processes are carried out. To inject carbon dioxide, it is necessary to install CO2 containers and equip a piping system capable of supplying carbon dioxide at a constant pressure to areas at risk of fire.

[0095] In addition, fires can be prevented in advance by controlling the temperature within the crushing space to be lower than the minimum explosive concentration (LEL). For example, since various types of batteries may leak electrolytes when crushed, fires caused by electrolyte vapor leakage can be prevented by lowering the temperature within the crushing space to a level lower than the electrolyte that reaches the previously calculated minimum explosive concentration (LEL) at the lowest temperature.

[0096] If no fire hazard is confirmed (No in 306), the control unit (210) proceeds to step 314 to check whether the battery has been shredded or if further shredding of the battery is required, and either completes the shredding of the battery (Yes in 314) or continues the shredding of the battery (302).

[0097] If a fire actually occurs despite the fire prevention measures (308) (e.g., 310), the control unit (210) takes measures to extinguish the fire (312). After a fire actually occurs during the battery crushing process, the fire can be extinguished by injecting a fire extinguishing agent. Since battery fires have characteristics different from general fires, it is desirable to use a suitable fire extinguishing agent that takes these characteristics into account. For example, potassium compounds (K-HCO) are useful fire extinguishing agents for extinguishing battery fires, particularly lithium-ion battery fires. Potassium compounds are sprayed directly onto the battery where the fire occurred, rapidly absorbing heat and blocking the flames.

[0098] When the risk of fire is reduced or eliminated or the battery is shredded through this process (e.g., 314), the control unit (210) completes the battery shredding operation. If the battery shredding is not yet complete (e.g., 314), the control unit (210) proceeds to step 320 and continues the battery shredding operation.

[0099] The above description is merely an illustrative explanation of the technical concept, and those skilled in the art will be able to make various modifications, changes, and substitutions within the scope of the essential characteristics without departing from the nature of the invention. Accordingly, the embodiments disclosed above and the attached drawings are intended to explain, not limit, the technical concept, and the scope of the technical concept is not limited by such embodiments and attached drawings. The scope of protection shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights.

Claims

1. A step of crushing at least one battery; A step of determining fire risk based on the electrolyte concentration in the air of the crushing space during the crushing process; and A battery crushing method comprising the step of taking predetermined measures to reduce the fire risk based on the fire risk assessment above.

2. In Paragraph 1, A battery crushing method for determining the fire risk based on the lower of the minimum explosive concentrations (LEL) of each of the two or more types of electrolytes when leakage of two or more types of electrolytes is expected in the battery.

3. In Paragraph 2, A battery crushing method for determining the fire risk based on the oxygen concentration of the crushing space along with the minimum explosive concentration (LEL) of the electrolyte.

4. In Paragraph 3, The method further includes the step of calculating the minimum oxygen concentration (MOC) required for ignition based on the minimum explosive concentration (LEL) of the electrolyte and the oxygen concentration. A battery crushing method for determining the fire risk based on the above minimum oxygen concentration (MOC).

5. In Paragraph 4, A battery crushing method for determining the fire risk by further considering the temperature change spikes occurring during the crushing of at least one battery.

6. In Paragraph 1, The predetermined measures to reduce the above fire risk are, A battery crushing method in which an inert gas is introduced into the crushing space.

7. In Paragraph 1, The predetermined measures to reduce the above fire risk are, A battery crushing method that lowers the oxygen concentration in the crushing space.

8. A shredder configured to shred at least one battery; It includes a control unit configured to control the crushing process of at least one battery, and The above control unit is, Determining the fire risk based on the electrolyte concentration in the air of the crushing space during the crushing process; and A battery crushing device that takes predetermined measures to reduce the fire risk based on the above fire risk assessment.

9. In claim 8, the control unit is, A battery crushing device that determines the fire risk based on the lower of the two or more types of minimum explosive concentrations (LEL) of each of the two or more types of electrolytes when leakage of two or more types of electrolytes is expected in the battery.

10. In claim 9, the control unit is, A battery crushing device that determines the fire risk based on the oxygen concentration of the crushing space along with the minimum explosive concentration (LEL) of the electrolyte.

11. In claim 10, the control unit is, Calculate the minimum oxygen concentration (MOC) required for ignition based on the minimum explosive concentration (LEL) of the above electrolyte and the above oxygen concentration; A battery crushing device that determines the fire risk based on the above minimum oxygen concentration (MOC).

12. In claim 11, the control unit is, A battery crushing device that determines the fire risk by further considering the temperature change spike occurring during the crushing of at least one battery.

13. In Paragraph 8, The predetermined measures to reduce the above fire risk are, A battery crushing device that introduces an inert gas into the crushing space.

14. In Paragraph 8, The predetermined measures to reduce the above fire risk are, A battery crushing device that lowers the oxygen concentration in the crushing space.

15. A step of crushing at least one battery; A step of determining fire risk based on the electrolyte concentration in the air of the crushing space during the crushing process; and A battery recycling method comprising the step of taking predetermined measures to reduce the fire risk based on the fire risk assessment above.

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