Method for heat treatment of battery, method for recovering valuable material and heat treatment device

Abstract

To heat-treat a battery at an optimal temperature by suppressing temperature rise due to thermal runaway of the battery during a heat treatment step.SOLUTION: There is provided a heat treatment method for heat-treating a battery from which a valuable material is recovered, the heat treatment method including: a battery loading step of loading a battery 1 into a heating case 10 that is blocked but not sealed; and a heat treatment step of heating the heating case 10 in a heat treatment furnace 3 and heating the battery 1 inside the case through the heating case 10 to heat-treat the battery. The heat treatment step includes a pretreatment step of forcibly exhausting internal air in the heating case 10, and a battery heating step. The pretreatment step includes: supplying extrusion water 2, which vaporizes itself and forcibly exhausts internal air, into the heating case 10 and heating the extrusion water 2 in the heating case; exhausting internal air with steam generated by heating; heating the heating case 10, from which internal air has been exhausted in the pretreatment step, in the heating step; and heat-treating a battery disposed in the heating case 10, in a state where a valuable material can be recovered.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for heat treating a battery to recover valuable materials from the battery, a method for recovering valuable materials by heat treating a battery, and a battery heat treatment device for recovering valuable materials from the battery. [Background technology]

[0002] Valuable materials can be recovered from batteries by heat treatment. Discarded batteries can be heat treated to remove the electrolyte and recover valuable materials. This recovery method can recover non-ferrous valuable materials such as lithium, cobalt, nickel, copper foil, and aluminum foil from lithium-ion secondary batteries, for example. Valuable materials can be recovered by heat treating the batteries, then crushing, pulverizing, and classifying them to separate each valuable material. The recovered valuable materials can be effectively reused as raw materials for batteries, so technology to recover valuable materials from batteries is extremely important in resource-poor Japan.

[0003] Batteries are placed in a heat treatment furnace and heated to a predetermined temperature for heat treatment. Heat treatment of batteries involves heating the batteries to a predetermined temperature and baking them to a state where valuables can be efficiently recovered from the heat-treated batteries. If the heat treatment temperature of the batteries is too high or too low, it will hinder the efficient recovery of valuables in a high-quality state. Heat treatment of batteries involves controlling the thermal energy supplied to the heat treatment furnace to maintain the battery temperature at an appropriate value. However, heated batteries can experience thermal runaway and emit high-temperature, high-pressure exhaust gases and other emissions. The high-temperature emissions emitted from the batteries rapidly increase the internal temperature of the heat treatment furnace, raising the battery heating temperature above the desired temperature. This melts or oxidizes the valuables to be recovered from the heat-treated batteries, reducing their quality and hindering the efficient recovery of high-quality valuables. Thermal runaway in batteries is believed to be caused by heat generated by Joule heat due to a short circuit current that flows when the positive and negative electrodes are shorted. Therefore, batteries that are not fully discharged, i.e., batteries with a large remaining capacity (SOC), have the problem of being prone to thermal runaway due to the large short circuit current.

[0004] Patent Document 1 discloses a technology in which, in order to suppress the adverse effects of thermal runaway, in a process of heat treating a lithium ion secondary battery with a voltage of 80% or more of its rated voltage, the lithium ion secondary battery is heated to 350°C or more and 430°C or less, and if the lithium ion secondary battery experiences thermal runaway and ignites during this heat treatment process, the thermal energy supplied to the heat treatment furnace is changed to 50% or less of the amount of heat supplied before the lithium ion secondary battery ignited. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-150282 Summary of the Invention [Problem to be solved by the invention]

[0006] Batteries are heat-treated, but the heat treatment process can cause thermal runaway in batteries. Therefore, it is impossible to completely eliminate thermal runaway in batteries during the heat treatment process. When a battery experiences thermal runaway, the internal temperature of the heat treatment furnace rises, but it is difficult to prevent the internal temperature rise due to thermal runaway. While the probability of thermal runaway can be reduced by lowering the set temperature during the heat treatment process, a low temperature range that heat-treats all batteries without causing thermal runaway does not allow for efficient recovery of valuable resources. Therefore, the adverse effect of random thermal runaway in unspecified batteries cannot be eliminated during the heat treatment process, and it is extremely difficult to prevent abnormal increases in the furnace temperature due to thermal runaway in batteries during the heat treatment process. Furthermore, in order to efficiently heat-treat a large number of discarded batteries, multiple batteries are placed in a heat treatment furnace and heat-treated simultaneously. Therefore, thermal runaway in a specific battery adversely affects the other batteries being heat-treated together, hindering the effective recovery of valuable resources.

[0007] The present disclosure was developed with the aim of eliminating the above-mentioned drawbacks, and one of the purposes of the present disclosure is to have the feature that even when the battery goes into thermal runaway during the heat treatment process and emits high-temperature, high-pressure exhaust, the rise in internal temperature due to the exhaust can be suppressed, the battery can be heat-treated within an optimal temperature range, and valuable materials can be efficiently recovered in high quality from the heat-treated battery. [Means for solving the problem]

[0008] A battery heat treatment method according to one aspect of the present disclosure is a heat treatment method for heat treating batteries from which valuables can be recovered, comprising a battery carrying-in step of placing batteries in a heating case that is closed but not sealed, and a heat treatment step of placing the heating case with the batteries placed in the carrying-in step into a heat treatment furnace, heating the heating case in the heat treatment furnace, and heating and heat-treating the internal batteries through the heating case. The heat treatment step includes a pretreatment step of forcibly discharging the internal air of the heating case, and a battery heating step. In the pretreatment step, extruded water that vaporizes itself is placed into the heating case, forcibly discharging the internal air, and the extruded water is heated in the heating case, and the internal air is discharged with the steam generated by heating. The heating case from which the internal air has been discharged in the pretreatment step is heated in the heating step, thereby heat-treating the batteries placed in the heating case to a state from which valuables can be recovered.

[0009] A method for recovering valuable materials from batteries according to another aspect of the present disclosure includes a heat treatment step of heat-treating the batteries using a heat treatment method including those described above, and a recovery step of crushing the heat-treated batteries obtained in the heat treatment step to separate and recover valuable materials.

[0010] A battery heat treatment device according to another aspect of the present disclosure includes a closed but not sealed heating case into which batteries are placed, and a heat treatment furnace that heats the heating case, the heating case having extruded water inside, and the extruded water inside the heating case being heated by heating the heating case, generating water vapor that expels the internal air, and the heating case from which the internal air has been expelled is heated by the heat treatment furnace, thereby heat-treating the batteries inside the heating case to a state in which valuables can be recovered. [Effects of the Invention]

[0011] The above method and apparatus have the advantage that they can suppress temperature rise due to thermal runaway of the battery during the heat treatment process, heat treat the battery within an optimal temperature range, and efficiently recover valuable materials from the battery in a high-quality state. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic cross-sectional view of a battery heat treatment method and a battery heat treatment apparatus according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a schematic cross-sectional view showing another example of the heating case. [Figure 3] FIG. 2 is a schematic cross-sectional view showing an example of a check valve. [Figure 4] FIG. 10 is a schematic cross-sectional view showing another example of a check valve. [Figure 5] FIG. 10 is a schematic cross-sectional view showing another example of a check valve. [Figure 6] FIG. 2 is a schematic cross-sectional view showing an example of a water container. [Figure 7] FIG. 2 is a schematic cross-sectional view showing an example of a storage section. [Figure 8] FIG. 10 is a schematic cross-sectional view showing another example of the storage section. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present disclosure will be described in detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms including these terms) will be used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meanings of these terms do not limit the technical scope of the present invention. Furthermore, parts that appear with the same reference numerals in multiple drawings indicate the same or equivalent parts or components. Furthermore, the embodiments shown below are specific examples of the technical concept of the present invention and are not intended to limit the present invention thereto. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended as examples and are not intended to limit the scope of the present invention thereto. Furthermore, the content described in one embodiment or example can also be applied to other embodiments or examples. Furthermore, the sizes and positional relationships of components shown in the drawings may be exaggerated for clarity of explanation.

[0014] A battery heat treatment method according to one embodiment of the present disclosure is a heat treatment method for heat treating batteries from which valuables can be recovered, comprising a battery carrying-in step of placing batteries in a heating case that is closed but not sealed, and a heat treatment step of placing the heating case with the batteries placed in the carrying-in step into a heat treatment furnace, heating the heating case in the heat treatment furnace, and heating and heat-treating the internal batteries through the heating case. The heat treatment step includes a pretreatment step of forcibly discharging the internal air of the heating case and a battery heating step. In the pretreatment step, extruded water that vaporizes itself is placed into the heating case, forcibly discharging the internal air, the extruded water is heated in the heating case, and the internal air is discharged with the steam generated by heating, and the heating case from which the internal air has been discharged in the pretreatment step is heated in the heating step, thereby heat-treating the batteries placed in the heating case to a state from which valuables can be recovered.

[0015] The above-described battery heat treatment method has the advantage that, in the heat treatment process, a rise in internal temperature due to thermal runaway of the battery is suppressed, and the battery is heat-treated within an optimal temperature range, allowing valuable materials to be efficiently recovered from the battery in a high-quality state. This is because the above-described battery heat treatment method includes a pretreatment process in which extruded water in a heating case is heated to generate steam, and the generated steam forcibly expels the initial air with a high oxygen concentration that is present in the heating case before heating, thereby lowering the oxygen concentration in the heating case and allowing the battery to be heat-treated. Even if the battery experiences thermal runaway and emits high-temperature, high-pressure exhaust gas or other emissions, the low-oxygen state prevents ignition and prevents or suppresses a rapid rise in internal temperature due to excessive thermal energy generated by ignition of the emissions. The battery is heat-treated within an optimal temperature range, creating a state suitable for valuable material recovery, allowing valuable materials to be efficiently recovered from the battery in a high-quality state. The above-described battery heat treatment method generates water vapor in the heating case, efficiently expels the initial internal air, and lowers the oxygen concentration, thereby enabling the battery to be heat-treated. Furthermore, in the heat treatment process, the battery is heat-treated at a temperature higher than the temperature at which water vapor is generated (100°C under atmospheric pressure). Therefore, before the temperature of the heating case heated in the heat treatment furnace rises to the battery heat treatment temperature (heating process), water vapor is generated from the extruded water in the pre-treatment process, and the internal air is forcibly expelled, thereby reliably lowering the oxygen concentration and enabling the battery to be heat-treated.

[0016] The above-described battery heat treatment method has the advantage of being able to efficiently reduce the oxygen concentration inside the heating case in a short period of time. This is because a closed heating case can limit the range in which the oxygen concentration is reduced to the required range while still housing the batteries. A heating case limited to a narrow, required range can forcibly expel the internal air, allowing for a rapid and efficient reduction in the oxygen concentration, compared to reducing the oxygen concentration throughout the entire heat treatment furnace. The above-described battery heat treatment method also has the advantage of being able to heat the entire battery in a temperature range favorable for recovering valuables. This is because the heat treatment furnace indirectly heats the internal batteries via the heating case, preventing the heat source of the heat treatment furnace from directly and locally heating the batteries. Furthermore, the internal air of the heated heating case rises along the inner surface, agitating the internal air through the convection action of the rising internal air, allowing for effective heating and heat treatment of batteries with minimal temperature variation. Furthermore, the above-described battery heat treatment method effectively utilizes the thermal energy of a heat treatment furnace to efficiently heat and heat-treat batteries, thereby reducing energy consumption and costs. This is because batteries are heated in a closed heating case and energy loss is reduced. The heat treatment furnace heats the heating case to heat the batteries and extruded water, and batteries can be heated and heat-treated continuously, continuously, or simultaneously using the heat generated by heating the heating case in the pretreatment process. Steam can be generated from the extruded water prior to the heat treatment process, allowing batteries to be heated simultaneously. Separate heating or heat source is not required for the pretreatment process, and there is no need to move the batteries or extruded water or change containers. The pretreatment process and battery heating process can be performed in the same heating case using the heat treatment furnace. Furthermore, the steam generated in the heating case is further heated to generate superheated steam, which is a gas with a large heat capacity and excellent heat transfer properties, allowing batteries to be heated and heat-treated efficiently. In addition, superheated steam has the property of preferentially condensing in low-temperature areas, which allows for the suppression of temperature variations and the effective heating of batteries. Superheated steam can also be used in a low-oxygen atmosphere.The above-mentioned battery heat treatment method ensures and improves the safety of the work by heat treating the batteries in a low-oxygen environment, and has the advantage that even in the unlikely event of an unforeseen incident, the heating case acts as a protective barrier, preventing or minimizing danger to workers and damage to the heat treatment furnace.

[0017] The above-described battery heat treatment method allows heat treatment without removing the battery's exterior case, eliminating the time, labor, and cost required for removing the exterior case and disassembling the battery, while also avoiding potential hazards. Furthermore, the above-described battery heat treatment method also allows safe heat treatment at a desired temperature by evacuating the internal air of the heating case, including the air inside the battery's exterior case. Batteries housed in an exterior case have difficulty smoothly guiding water vapor into the interior of the exterior case, making it difficult to quickly evacuate the air inside the exterior case using water vapor. However, when a battery including the exterior case is heated in a heat treatment furnace, the air inside the exterior case expands and gradually escapes from the exterior case. The air escaping from the exterior case temporarily increases the oxygen concentration inside the heating case, potentially increasing the risk of fire. However, by evacuating the internal air, including the air escaping from the exterior case, the oxygen concentration inside the heating case can be reduced. Water vapor can efficiently heat batteries by utilizing a large amount of heat retention, not only through convective heat transfer but also through condensation and radiative heat. The water vapor heats the battery, including the exterior case, through convection and radiative heat transfer caused by condensation of the water vapor on the surfaces of the battery and exterior case, followed by evaporation of the water, which promotes the outflow of air from the exterior case and the discharge of this and other internal air to the outside, thereby reducing the oxygen concentration within the heated case.The above battery heat treatment method can be used to heat treat batteries of various types in a heated case, but there is particularly high demand for the recovery and recycling of valuable materials in batteries (battery units) that house many battery cells in a metal exterior case used as a power source for hybrid cars, electric vehicles, etc., and the above features can solve important issues.

[0018] The above-described battery heat treatment method has the advantage that the amount, generation time, and generation location of the water vapor generated can be easily determined and adjusted by the amount, placement, and storage mode of the extruded water. This battery heat treatment method has the advantage of increasing the amount of water vapor generated from the extruded water and / or extending the water vapor generation time, thereby promoting the discharge of internal air and stably lowering the overall oxygen concentration. The water vapor generated from the extruded water has a lower density than the internal air, so it can displace and push out the internal air, filling the battery with water vapor. Furthermore, the highly saturated water vapor can efficiently displace and expel the initial air with a high oxygen concentration remaining before heating. Furthermore, the extruded water can efficiently fill the heating case with water vapor in a short time. Furthermore, the extruded water can continuously generate gaseous water vapor close to the battery, covering the battery with water vapor regardless of the battery's external shape, heating the battery, and promoting the discharge of air from the exterior case. The placement and amount of extruded water can be easily determined and adjusted. The extruded water can be placed in various ways. For example, it can be placed exposed, in a container, or absorbed in a water-absorbing material, and the amount and timing of water vapor generation can be adjusted.

[0019] The above-described battery heat treatment method has the advantages of reducing costs and avoiding the need for large-scale equipment through a simple structure and method of placing extruded water in a heating case. Supplying steam (or water) into a heat treatment furnace during the battery heat treatment process requires a separate heat source to generate steam and a complex or dedicated mechanism or structure for supplying the steam. This requires fire resistance and heat resistance to withstand the furnace temperatures, increasing equipment costs and the size of the equipment. In contrast, the present disclosure effectively reduces the oxygen concentration in a heating case using an extremely simple structure and method of placing extruded water in a heating case before heating. This eliminates the need for a separate heat source and the need for a complex or dedicated mechanism or structure for supplying steam into the heat treatment furnace, thereby avoiding increased equipment costs and the size of the equipment. Furthermore, the liquid used for extruded water is low-cost water, which can be easily placed and supplied into the heating case in a short time, reducing processing and running costs. Furthermore, the above-described battery heat treatment method, by placing batteries in a heating case to heat treat them, can expand the types and range of heat treatment furnaces that can be used. This is because the heat treatment furnace does not directly heat-treat the batteries, but instead indirectly heats and heat-treats the batteries and extruded water inside via the heating case, eliminating the need for a dedicated mechanism, structure, or dedicated heat treatment furnace, and the heating case prevents the heat treatment furnace from being damaged by the battery heat treatment. Furthermore, the above battery heat treatment method has the advantage that the extruded water can be safely placed in the heating case before heating. Heating can begin in the heat treatment furnace after the extruded water and batteries are placed in the heating case.

[0020] Another embodiment of the present disclosure provides a heat treatment method for a battery that uses a closed but not sealed metal case equipped with a check valve that allows gas to pass through the heating case in the direction of exhausting the internal air but prevents gas from passing in the opposite direction. The check valve prevents the inflow of external air, including backflow of the internal air once exhausted, thereby reliably reducing the oxygen concentration inside the heating case and maintaining a low-oxygen state. Metal heating cases have high thermal conductivity, allowing for efficient heating of the interior, reducing temperature variations, and reducing heating energy consumption.

[0021] In another embodiment of the present disclosure, a battery heat treatment method includes a check valve having a valve element that elastically deforms and opens under the internal pressure of the heating case. The valve element elastically closes to a valve seat and can open when the valve element is pushed away from the valve seat by the internal pressure of the heating case. The above heat treatment method provides excellent heat resistance for the check valve, allowing it to be installed in a heating case placed in a high-temperature heat treatment furnace and operate reliably to exhaust air from the heating case and prevent backflow of air within the furnace. The above heat treatment method allows the check valve opening timing to be set to an appropriate value and adjusted based on the internal pressure of the heating case. Multiple check valves can be easily opened at different times and with different time lags using different elastic deformation strengths. A check valve that opens when the internal pressure of the heating case exceeds a certain level can mitigate an increase in the internal pressure of the heating case by opening, maintaining the internal pressure within a certain range while exhausting the air from the heating case, thereby reducing and maintaining a low oxygen concentration. The above heat treatment method has the advantage of being simple in structure and low in cost.

[0022] In another embodiment of the present disclosure, a battery heat treatment method includes a check valve having a heat-resistant valve body placed on a discharge opening of a heating case, the valve body tightly contacting a valve seat under its own weight to close, and the valve body being pushed by the internal pressure of the heating case to separate from the valve seat to open. This heat treatment method allows the pressure at which the check valve opens under the weight of the valve body to be set and adjusted to an appropriate value, and also provides excellent heat resistance for the check valve, allowing it to be installed in a heating case placed in a high-temperature heat treatment furnace and operate stably and reliably. This heat treatment method also has the advantage of being simple in structure and allowing for low cost.

[0023] In another embodiment of the present disclosure, a battery heat treatment method can include placing both a battery and extruded water in a heating case during a pretreatment step, and then transporting the heating case containing the battery and extruded water into a heat treatment furnace. This heat treatment method allows the battery and extruded water to be easily and safely placed in the heating case before heating the heating case in the heat treatment furnace, which is the pretreatment step, and has the advantage of reducing running costs. Furthermore, this heat treatment method does not require a complex, large, or dedicated mechanism or structure for supplying extruded water or steam after heating begins, and therefore has the advantage of reducing equipment costs.

[0024] In another embodiment of the present disclosure, a battery heat treatment method can include placing extruded water in a water container and placing the water container in a heating case. This battery heat treatment method has the advantage that the timing at which the water container supplies extruded water or steam into the heating case can be determined and adjusted.

[0025] In a battery heat treatment method according to another embodiment of the present disclosure, the water container can be a container whose opening is closed with an openable lid that opens when the extruded water boils. The above battery heat treatment method has the advantage that boiled extruded water is supplied from the opening of the water container, and water vapor can forcibly expel the internal air in the heating case.

[0026] In another embodiment of the present disclosure, a battery heat treatment method includes a heating case having a top lid that closes an opening for inserting a battery, the top lid having a storage compartment for extruded water, and a communication opening that connects the storage compartment to the inside of the heating case. During the heat treatment process, the extruded water in the storage compartment is heated in a heat treatment furnace, and the generated steam flows into the heating case through the communication opening, allowing the internal air to be discharged. This battery heat treatment method allows the steam from the extruded water to flow from the storage compartment into the heating case through the communication opening, forcibly discharging the internal air within the heating case. This method has the advantage of efficiently discharging the internal air to the outside while expanding the area filled with high-concentration steam from the top to the bottom of the heating case. This battery heat treatment method has the advantage of allowing the top lid to close the heating case, while at the same time allowing the extruded water 2 to be easily positioned in a predetermined position.

[0027] In another embodiment of the present disclosure, a heat treatment method for a battery can be implemented by filling the entire or nearly entire bottom surface of the heating case with extruded water, which can expel internal air using vaporized water vapor. The heat treatment method described above has the advantage that extruded water is placed over the entire or nearly entire bottom surface of the heating case, and the generated water vapor envelops the battery, reducing the oxygen concentration around the battery and effectively preventing combustion or ignition of the discharged material. Note that "almost the entire bottom surface of the heating case" refers to at least 90% of the bottom surface of the heating case.

[0028] A heat treatment method for a battery according to another embodiment of the present disclosure includes introducing extruded water into multiple locations within a heating case and using vaporized water vapor to expel internal air. This heat treatment method has the advantage that water vapor is generated from the extruded water disposed in multiple locations, reducing the oxygen concentration within the heating case and effectively preventing combustion or ignition of the exhaust. This heat treatment method also has the advantage that the amount of water vapor generated can be determined and adjusted depending on the location within the heating case.

[0029] In a heat treatment method for a battery according to another embodiment of the present disclosure, in the pretreatment step, extruded water is poured into the heating case in an amount equal to or greater than the internal volume (liters) of the heating case x 0.8 cc, and the internal air can be expelled from the heating case by the water vapor generated by vaporizing the extruded water. This heat treatment method has the advantage that the internal air can be expelled from the heating case by vaporizing the extruded water and expanding it to a volume equal to or greater than the internal volume of the heating case.

[0030] In a heat treatment method for a battery according to another embodiment of the present disclosure, in the pretreatment step, extruded water is supplied to a heating case that has a battery placed therein and is carried into a heat treatment furnace, and the supplied extruded water is evaporated in the heating case to generate water vapor, which can be used to exhaust the internal air. The above heat treatment method has the advantage that extruded water is supplied to a heating case that has a battery placed therein and is carried into a heat treatment furnace, and the water vapor generated reduces the oxygen concentration inside the heating case, thereby effectively preventing ignition of exhaust materials.

[0031] A battery heat treatment method according to another embodiment of the present disclosure can convert a battery into a lithium-ion secondary battery. The above-described heat treatment method has the advantage of being able to perform heat treatment at an optimal temperature for efficiently recovering high-quality valuable materials from the heat-treated lithium-ion secondary battery.

[0032] A method for recovering valuable materials from batteries according to another embodiment of the present disclosure can recover valuable materials from batteries, including a recovery step of crushing the heat-treated batteries obtained in the heat treatment step to separate and recover the valuable materials. The above-described valuable material recovery method has the advantage of being able to efficiently recover high-quality valuable materials from heat-treated batteries.

[0033] In another embodiment of the present disclosure, a method for recovering valuables from batteries can include a separation step of crushing the heat-treated batteries and separating black mass containing valuables from the crushed material in the recovery step. The above-described method for recovering valuables has the advantage of being able to efficiently recover high-quality valuables from the heat-treated batteries by separating black mass containing valuables from the crushed material of the heat-treated batteries.

[0034] In another embodiment of the present disclosure, a method for recovering valuable resources from a battery includes the step of recovering valuable resources from the battery, wherein the black mass contains at least one non-ferrous metal selected from the group consisting of cobalt, nickel, lithium, copper, and aluminum. The method for recovering valuable resources described above has the advantage of being able to efficiently recover valuable resources containing any of cobalt, nickel, lithium, and aluminum from a heat-treated battery.

[0035] A method for recovering valuable materials from a battery according to another embodiment of the present disclosure can recover valuable materials from a battery having a copper foil or aluminum foil as an electrode core. The above-described method for recovering valuable materials has the advantage of being able to efficiently recover valuable materials from a battery having a copper foil or aluminum foil as an electrode core.

[0036] Another embodiment of a battery heat treatment device according to the present disclosure includes a closed but not sealed heating case in which batteries are placed, and a heat treatment furnace that heats the heating case, the heating case having extruded water inside, and the extruded water inside the heating case being heated by the heat treatment furnace, generating water vapor that expels the internal air, and the heating case from which the internal air has been expelled is heated by the heat treatment furnace, thereby heat-treating the batteries inside the heating case to a state in which valuables can be recovered.

[0037] The above-described battery heat treatment device has the advantage that, by heating the extruded water in the heating case and generating steam that expels internal air, it is possible to suppress an increase in internal temperature due to the discharged material, even in a state in which the battery experiences thermal runaway during the heat treatment process and emits high-temperature, high-pressure discharged material, thereby heat-treating the battery within an optimal temperature range and achieving a state in which valuable materials can be recovered with high quality and / or efficiently from the heat-treated battery. The above-described battery heat treatment device has the advantage of being able to reliably reduce the oxygen concentration in the heating case and heat-treat the battery. The above-described battery heat treatment device has the advantage of being able to efficiently reduce the oxygen concentration in the heating case in a short period of time. The above-described battery heat treatment device has the advantage of being able to prevent the adverse effects of localized heating of the battery by housing the battery in the heating case and heat-treat the entire battery within a temperature range favorable for recovering valuable materials. The above-described battery heat treatment device has the advantage of being able to effectively utilize the thermal energy of the heat treatment furnace to efficiently heat and heat-treat the battery, thereby reducing energy consumption. The above-described battery heat treatment device has the advantage of being able to efficiently heat and heat-treat batteries using superheated steam generated by further heating water vapor, and is also able to improve the safety of battery heat treatment. (Embodiment 1)

[0038] The battery heat treatment device 100 shown in the schematic diagram of Figure 1 includes a heating case 10 that is closed but not sealed and that holds batteries 1, and a heat treatment furnace 3 that heats the heating case 10. The heating case 10 contains extruded water 2, and when the heating case 10 is heated by the heat treatment furnace 3, the extruded water 2 inside the heating case 10 is heated, and the generated water vapor expels the internal air. The heating case 10 from which the internal air has been expelled is then heated by the heat treatment furnace 3, thereby heat-treating the batteries 1 inside the heating case 10 to a state where valuables can be recovered. (Battery 1)

[0039] Battery 1 is a battery containing at least valuable materials to be recovered. Battery 1 may be, for example, a used or discarded battery, including batteries that have reached the end of their service life, defective batteries that developed a malfunction during manufacture or subsequent use, batteries discarded mid-use, batteries in devices that have reached the end of their service life, batteries in defective devices that developed a malfunction during manufacture or subsequent use, and batteries in devices that have been discarded mid-use. Because the present disclosure involves heat-treating battery 1 to recover valuable materials from its constituent materials, the present disclosure does not specify the structure, shape, size, capacity, mode, or type of battery 1 to be heat-treated. For example, the battery may include a positive electrode, a negative electrode, a separator, an electrolyte, and a battery case, cover, film, or other container that accommodates these components. Furthermore, while the present disclosure does not specify the type of battery, because valuable materials can be recovered by heat-treating the battery, batteries with excellent characteristics that are currently widely used, particularly lithium-ion secondary batteries with a large charge / discharge capacity relative to their weight and volume, are suitable for battery 1. However, the present disclosure does not limit the battery 1 to a lithium ion secondary battery, as valuable materials can be recovered from any battery that can be subjected to heat treatment to recover valuable materials.

[0040] In the present disclosure, battery 1 refers to one or more batteries. Battery 1 is not limited to a single battery cell, but is used in a broad sense to include a battery unit having multiple battery cells and even multiple battery units. A battery unit is a battery used as a power supply device, in which multiple secondary batteries, such as lithium-ion secondary batteries used to power the traction motor of an electric vehicle, are placed in a metal exterior case. Valuable materials can be recovered from a battery unit by disassembling it into battery cells or by heat treating it without disassembly. By heat treating a battery unit without disassembling it into individual battery cells, the present disclosure has the advantage of reducing the cost, effort, and time required for disassembly, preventing accidents caused by battery disassembly, and allowing for safe recovery of valuable materials. Furthermore, because a battery unit contains multiple batteries inside a metal exterior case, heat treating the battery unit to recover valuable materials has the advantage of recovering the metal materials of the exterior case in addition to the constituent materials of battery 1.

[0041] The valuables recovered in this disclosure are specified by the constituent materials of the battery 1. For example, valuables recovered from a lithium-ion secondary battery include copper foil, aluminum foil, cobalt, nickel, and lithium, which are constituent materials of the electrodes, as well as the metal material of the outer case. For example, copper foil and aluminum foil can be recovered as valuables from a battery 1 that uses copper foil or aluminum foil as the electrode core. Since the valuables recovered by heat treatment vary depending on the constituent materials of the battery 1, this disclosure does not specify the valuables recovered from the battery 1, but rather specifies them by the constituent materials of the battery 1 and the outer case. (Heating Case 10)

[0042] The heating case 10 is a container that houses the battery 1 and heat-treats the battery 1. The heating case 10 is heated in a heat treatment furnace 3, and the battery 1 inside the heating case 10 is heated and heat-treated. Extruded water 2 is placed in the heating case 10, and the extruded water 2 generates steam, forcibly expelling the internal air, creating a low-oxygen state (low-oxygen atmosphere) inside the heating case 10. The heating case 10 expels the internal air with steam, creating a low-oxygen state below an oxygen concentration that effectively prevents and suppresses ignition or a sudden rise in internal temperature due to ignition. The heating case 10 forms a limited, closed space, which can efficiently forcibly exhaust the internal air of the heating case 10 and efficiently create a low-oxygen state in a short period of time. Furthermore, the heating case 10 effectively prevents and suppresses ignition and a sudden rise in internal temperature in a low-oxygen state, allowing the battery 1 to be safely heat-treated. The heating case 10 has a closed, but not sealed, structure. The heating case 10 has an opening for inserting and removing the battery 1, and the battery 1 inserted through the opening is placed in a predetermined position and posture, and is closed with a closing part such as a lid or door. The heating case 10 in FIG. 1 has an exhaust opening 11 for discharging the internal air and a check valve 20, and has a non-sealed structure. The shape, size, structure, material, etc. of the heating case 10 are not specified, and any heating case that can store and place the battery 1 and extruded water 2 inside and heat-treat the battery 1 can be used. This includes heating cases that are currently in use and those that will be developed in the future.

[0043] The heating case 10 stores one or more batteries 1 (including a battery block or battery unit having multiple battery cells) in a predetermined position and posture. By storing multiple batteries 1 in the heating case 10, the efficiency of heat treatment can be improved. The heating case 10 is shaped to match the external shape of the stored batteries 1, which reduces gaps and spaces within the heating case 10, allowing for efficient and quicker exhaust of internal air, and reduces temperature variations and ensures uniform heat treatment temperatures.

[0044] The heating case 10 can be made from a material with excellent heat resistance, for example, a metal such as a heat-resistant stainless steel plate. Plate-shaped cases are easy to process and can be made low cost. A metal heating case 10 has high thermal conductivity and can efficiently conduct heat to the internal batteries 1, reducing internal temperature variations and reducing and suppressing heating energy consumption. The heating case 10 has fire resistance and heat resistance strength that allows it to heat-treat the batteries 1 by heating them in the heat treatment furnace 3, and also has pressure resistance strength that can withstand increases in internal pressure. It is also preferable that the heating case have explosion-proof strength to enable safer heat treatment.

[0045] The heating case 10 in FIG. 1 is a hollow rectangular parallelepiped formed from a plate material. The heating case 10 in FIG. 1 has a top surface 10a (top plate), side surfaces 10b, and a bottom surface 10c. The heating case 10 can be shaped other than a rectangular parallelepiped, such as a cube, a cylindrical body such as a cylinder or a rectangular tube, a cone or pyramid, a polyhedron, or a shape with curved surfaces. The heating case 10 can be shaped to suit the heat treatment, valuable resource recovery, and various processes of the present disclosure, such as heating, loading, placement, and standing of the battery 1, inserting and removing the battery 1, and venting the internal air. The heating case 10 can be formed with flat surfaces, curved surfaces, or a combination of flat and curved surfaces, and can have unevenness on the outside or inside and different thicknesses. The shape (internal shape) of the heating case 10 can be shaped to allow the internal air to escape favorably. For example, it is preferable to avoid unnecessary shapes that hinder the pushing and venting of the internal air. A simple internal shape contributes to the discharge of internal air and low costs. The heating case 10 can also be shaped to enable the smooth discharge of internal air to the exhaust opening 11. A guide or the like can be provided to direct the internal air to the exhaust opening 11. The case can also be shaped to reduce the accumulation or retention of internal air. For example, if the heating case 10 has a cone shape that tapers toward the exhaust opening 11 (check valve 20) side through which the internal air is discharged, the steam can smoothly discharge the internal air toward the exhaust opening 11, making it easier to discharge the internal air to the outside.

[0046] The heating case 10 has an exhaust opening 11 for discharging the internal air to the outside. The heating case 10 is filled with steam and the internal air, including the initial air with a high oxygen concentration, is discharged to the outside through the exhaust opening 11. The exhaust openings 11 are provided with an appropriate size, shape, number, and position so that the internal air can be discharged using the steam generated from the extruded water 2. The heating case 10 can have one or more exhaust openings 11 on the top surface 10a, side surface 10b, bottom surface 10c, upper, middle, or lower portion of the heating case 10. The multiple exhaust openings 11 allow the internal air in the heating case 10 to be discharged to the outside from multiple locations in a dispersed manner, reducing the accumulation of residual air and efficiently reducing the oxygen concentration in the heating case 10 in a short period of time.

[0047] The exhaust opening 11 can be located close to or far from the extruded water 2. For example, the exhaust opening 11 can be located away from the extruded water 2, or on the opposite side of the battery 1 from the direction of the steam generated from the extruded water 2 immediately after its generation, thereby extending the residence time of the steam, efficiently displacing the internal air, and filling the heating case 10 with steam. The location of the exhaust opening 11 is determined taking into consideration the relative positions of the exhaust opening 11 and the extruded water 2, the steam-filled area, the generation and direction of steam, etc., and is preferably located at a position where the steam can easily displace the internal air and be efficiently discharged from the exhaust opening 11. It is also preferable to locate the exhaust opening 11 at a position where the steam can easily reside inside the heating case 10 and be easily filled with steam. The exhaust opening 11 can be located above, below, or at the same height as the extruded water 2 in the heating case 10. The exhaust opening 11 in the heating case 10 can be located above the extruded water 2. For example, as shown in FIG. 1, the exhaust opening 11 can be provided at the top of the heating case 10. In this heating case 10, water vapor, which is lighter in density than the internal air, is continuously generated upward, repeatedly driving and pushing out the internal air from bottom to top, and the internal air can be discharged to the outside through the exhaust opening 11 at the top. To prevent internal air from accumulating near the exhaust opening 11, the exhaust opening 11 can be provided on the top surface 10a, the top, or a side surface of the upper part. The exhaust opening 11 in the heating case 10 can also be provided below the extruded water 2. For example, as shown in FIG. 2, the exhaust opening 11 can be provided at the bottom of the heating case 10. In this heating case 10, water vapor is continuously generated upward from the extruded water 2 arranged above the exhaust opening 11, filling the upper part with water vapor. As the water vapor concentration increases, the area filled with water vapor expands from top to bottom, driving and pushing out the internal air downward, and the internal air can be discharged to the outside through the exhaust opening 11 at the bottom. (Check valve 20)

[0048] The check valve 20 allows the internal air inside the heating case 10 to pass in the discharge direction while preventing the external air (outside air) outside the heating case 10 from passing in the opposite direction (intake direction). The check valve 20 allows the water vapor from the extrusion water 2 to pass in the direction of exhausting the internal air with a high oxygen concentration that was present inside the heating case 10. By preventing the ingress and passage of external air outside the heating case 10, the oxygen concentration inside the heating case 10 can be reliably reduced. The check valve 20 also maintains a low-oxygen state. The external air includes the discharged internal air, and the check valve 20 can prevent the backflow of internal air once discharged. The heating case 10 has one or more check valves 20 that exhaust the internal air to the outside and reduce the internal oxygen concentration. The heating case 10 has a check valve 20 connected or communicated with a discharge opening. For example, the check valve 20 can be provided directly at the discharge opening 11, eliminating the need for a communication path from the discharge opening 11. The check valve 20 may also be provided in a communication path that connects a plurality of discharge openings 11. The structure, configuration, mechanism, etc. of the check valve 20 are not specified, but examples are shown below.

[0049] The check valve 20 includes a valve element 21 and a valve seat 23. For example, the check valve 20 can be opened and closed by an elastically deformable member of the valve element 21, and the elastically deformable member may be a member of the valve element 21, a member other than the valve element 21, or the valve element 21 itself. In the check valve 20 of Figures 3 and 4, the valve element 21 is pushed by the internal pressure of the heating case 10 and moves away from the valve seat 23 to open (indicated by the solid line in the figures), and the valve element 21 comes into close contact with the valve seat 23 to close (indicated by the dashed line in the figures). 3 has a valve element 21 that opens (moves up and down in the figure) when the internal pressure in the heating case 10 rises, a valve seat 23 with a through hole 22 that opens and closes the valve element 21, a spring 24 that is an elastically deformable member that elastically presses the plate-shaped valve element 21 against the valve seat 23, a threaded rod 25 that adjusts the valve-opening pressure by moving the spring 24 (moves up and down in the figure), and a closure plate 27 with a female threaded hole 26 into which the threaded rod 25 is screwed. This check valve 20 has the advantage that the valve-opening pressure can be adjusted by rotating an adjustment knob 28 fixed to the rear end (lower end) of the threaded rod 25 to move the threaded rod 25 up and down, thereby adjusting the pressure with which the spring 24 presses the valve element 21 against the valve seat 23 via a pressure plate 29. In the figure, when the adjustment knob 28 is turned to loosen the threaded rod 25, the force with which the spring 24 presses the valve element 21 against the valve seat 23 decreases, thereby decreasing the valve opening pressure. Conversely, when the adjustment knob 28 is turned to tighten the threaded rod 25, the valve opening pressure can be increased. The valve element 21 is set to a cracking pressure at which the valve opens after steam is generated from the extruded water 2. The valve opening pressure of the valve element 21 is set to a temperature above the boiling point of the extruded water 2, at which steam fills the heating case 10, forcibly expelling the internal air and reducing the oxygen concentration; for example, the cracking pressure at which the valve opens can be set to between 10 kPa and 100 kPa.

[0050] The check valve 20 can include a valve element 21 made of an elastic metal plate that elastically deforms under the internal pressure of the heating case 10 to open, and a valve seat 23. The cross-sectional view of Figure 4 illustrates a leaf spring 21a in which the valve element 21 itself elastically deforms. This check valve 20 opens when the leaf spring 21a is pushed away from the valve seat 23 by the internal pressure of the heating case 10 (solid line in the figure), and closes when the leaf spring 21a of the valve element 21 presses against the valve seat 23 using its own elastic restoring force (dotted line in the figure). This allows for a simple structure with a small number of parts, which allows for low costs. The check valve 20 shown in the figure has a structure in which the surface of the valve seat 23 against which the leaf spring 21a presses is an inclined surface against which the flat leaf spring 21a presses against using its elastic restoring force, allowing the leaf spring 21a to press against the surface of the valve seat 23 without any gaps to close the valve. This check valve 20 opens when the leaf spring 21a is pressed by the internal pressure of the heating case 10, so the cracking pressure is determined by the thickness, elastic deformation rate, and material of the leaf spring 21a. The cracking pressure at which this check valve 20 opens can be adjusted by replacing the leaf spring 21a; for example, the cracking pressure can be lowered by making the leaf spring 21a thinner, or higher by making it thicker.

[0051] The cross-sectional view of Figure 5 illustrates a check valve 20 in which a valve element 21 closes under its own weight. This check valve 20 includes a heat-resistant valve element 21 placed on the discharge opening 11 of the heating case 10, and the valve element 21 closes by its own weight as it comes into close contact with a valve seat 23 (dotted line in the figure), and opens when it is pushed by the internal pressure of the heating case 10 away from the valve seat 23 (solid line in the figure). The check valve 20 in this figure has a spherical valve element 21b, and closes by its own weight as the spherical valve element 21 comes into close contact with a valve seat 23 of a through hole 22 that is smaller in outer diameter than the spherical valve element 21b. The cracking pressure of this check valve 20 can be adjusted by adjusting the weight of the spherical valve element 21b and the inner diameter of the through hole 22 of the valve seat 23. The cracking pressure can be increased by making the weight of the valve element 21 heavy and the through hole 22 of the valve seat 23 small, or the cracking pressure can be adjusted to be low by making the valve element 21 light and the through hole 22 of the valve seat 23 large. The check valve 20 of this structure also has the advantage of being simple in structure and operating reliably.

[0052] The check valve 20 described above opens and closes the valve element 21 using the elastic restoring force of a spring or gravity (its own weight). However, the present disclosure does not limit the check valve 20 that opens by detecting pressure to the above structure. It is also possible to use check valves 20 with any other structure in which the valve element opens and closes when a predetermined condition other than pressure is detected. The check valve 20 may be configured to open and close by detecting, for example, temperature instead of pressure. A check valve 20 that opens and closes by detecting temperature may be a valve that opens when the temperature exceeds the boiling point of the extrusion water 2. Since the internal pressure of the heating case 10 increases as the extrusion water 2 boils, a check valve 20 that opens and closes by detecting temperature may be a valve that opens when the internal pressure of the heating case 10 exceeds the external pressure. For example, the check valve 20 may include a bimetal 21c that detects the temperature of the heating case 10 and may be formed into a plate shape as shown in FIG. 4. A bimetal is made by bonding together multiple metals with different thermal expansion coefficients and has the property of deforming with temperature changes. This check valve 20 uses a bimetal 21c as the valve element 21, which deforms at a predetermined temperature (set temperature). When the set temperature is reached, the bimetal 21c deforms and separates from the valve seat 23, opening the valve. This check valve 20 allows adjustment of the valve opening pressure by adjusting the temperature characteristics of the bimetal 21c. The bimetal 21c is made by laminating metal plates with different thermal expansion coefficients, so the temperature characteristics can be adjusted by selecting the metal plates to be laminated. The temperature characteristics of the bimetal 21c are such that it deforms at or above the boiling point of the extrusion water 2, separating from the valve seat 23 and opening the valve. The check valve 20, which opens by detecting temperature, is not limited to using a bimetal as the temperature detection element or structure, and can also use any other mechanism that can open or close the valve element using temperature, such as a combination of a temperature-sensitive ferrite whose magnetic attraction decreases at the Curie temperature with a permanent magnet.

[0053] The check valve 20, which opens and closes mechanically by utilizing the elastic restoring force of a spring, gravity, or deformation due to temperature, does not require an electronic signal and has the advantage of being able to open reliably when the extrusion water 2 is boiling, avoiding stoppage of opening and closing operations or abnormal operations due to software control failure. However, the opening and closing of the check valve 20 can also be controlled electronically. (Extrusion water 2)

[0054] The extruded water 2 is water that boils to generate steam. The extruded water 2 boils to generate steam, which pushes out the internal air in the heating case 10 and is discharged to the outside. In Figures 1 and 2, the extruded water 2 is placed inside the heating case 10. When the heating case 10 is heated in the heat treatment furnace 3, the extruded water 2 boils to generate steam. The steam fills the heating case 10, pushing out the internal air and forcibly discharging it outside the heating case 10. When the extruded water 2 is placed inside the heating case 10 before heating the heating case 10, initial air exists inside the heating case 10, and the oxygen concentration is the same as that of the outside air (e.g., 21%). When heating of the heating case 10 begins, the extruded water 2 vaporizes, filling the limited space inside the heating case 10 with steam, which drives out the internal air and forcibly discharges it outside through the exhaust opening 11, thereby lowering the oxygen concentration inside the heating case 10.

[0055] The heating case 10 accommodates the extruded water 2 at a predetermined location. The extruded water 2 can be positioned above, below, or at the same height as the exhaust opening 11 within the heating case 10. For example, in FIG. 1, the extruded water 2 is positioned below the exhaust opening 11. In this heating case 10, water vapor, which is lighter in density than the internal air, is generated upward one after another. The rising water vapor drives the internal air from the bottom to the top, and is then pushed and discharged to the outside through the upper exhaust opening 11. The extruded water 2 can be positioned at the bottom of the heating case 10. The extruded water 2 can be positioned over the entire or almost entire bottom surface 10c of the heating case 10. Extruded water 2 positioned over the entire bottom surface 10c generates water vapor evenly over a wide area, filling the heating case 10 with water vapor. In FIG. 1, the extruded water 2 is positioned below the battery 1 and covers the bottom of the battery 1, generating water vapor around the battery 1. The low-density water vapor that is generated one after another rises along the bottom and sides of the battery 1, enveloping the battery 1 from the bottom side, driving upward the internal air around the battery 1, including the initial air with a high oxygen concentration, thereby reducing the oxygen concentration around the battery 1 and effectively preventing ignition of the discharged material from the battery 1. The battery 1 is preferably disposed at a distance from the bottom of the heating case 10. This is because the water vapor flows along and into the battery 1, reducing the amount of residual initial air with a high oxygen concentration around the battery 1 and enabling the battery 1 to be heated with minimal temperature variation.

[0056] In Figure 2, the extruded water 2 is placed above the discharge opening 11. In this heating case 10, steam is continuously generated upward from the extruded water 2, filling the upper part of the heating case 10 with steam, and the continuously generated steam stirs the steam, increasing the degree of steam filling. As the area filled with steam expands from top to bottom, the internal air is forced downward, and the internal air is pushed out through the discharge opening 11 at the bottom and discharged to the outside. The extruded water 2 can be sprayed or placed in a container and placed in contact with or close to the battery 1, and this extruded water 2 or container can heat the battery 1 below while filling the upper part of the heating case 10 with steam.

[0057] The heating case 10 can have extruded water 2 disposed in one or more locations. Extruded water 2 disposed in multiple locations generates steam from multiple locations, efficiently displacing internal air and filling the heating case 10 with steam. In addition, steam can be generated according to the shape of the battery 1 or heating case 10, reducing residual internal air, and further generating steam at a predetermined timing and / or in a predetermined amount at each location.

[0058] The extruded water 2 generates a predetermined amount of steam or more, forcibly expelling the air inside the heating case 10. The amount of extruded water 2 is determined so that the vaporized steam expands to a volume equal to or greater than the internal volume of the heating case 10, thereby expelling the internal air. Because water (liquid) dramatically increases in volume when vaporized into steam (gas), a small amount of water relative to the volume of the heating case 10 can fill the heating case 10 with steam. For example, the extruded water 2 is preferably equal to or greater than the internal volume (liters) of the heating case 10 multiplied by 0.8 cc, more preferably equal to or greater than the internal volume (liters) of the heating case 10 multiplied by 1.5 cc, and even more preferably equal to or greater than the internal volume (liters) of the heating case 10 multiplied by 2 cc. 0.8 cc of extruded water 2 (water) boils to produce 1 liter of steam. Therefore, when the extruded water 2 is equal to or greater than the internal volume (liters) of the heating case 10, the volume of steam generated by boiling exceeds the internal volume of the heating case 10, allowing the steam to expel the air inside the heating case 10 and lower the oxygen concentration. The heating case 10 having the check valve 20 can maintain a low oxygen concentration in the heating case 10 by using the steam generated from the extruded water 2 during the temperature range (time) of the heat treatment in which thermal runaway of the battery 1 is a concern.

[0059] The amount of steam generated, the time it takes to generate steam, and the amount and time it takes to be released from the container can be determined and adjusted by adjusting the amount, depth, placement, presence or absence of exposure, the degree of exposure, the contact area with the inner surface of the heating case 10, the separation distance, the presence or absence of a container, intervening member, or contact member, and their thermal conductivity and thickness. For example, a metal water container 4 can quickly heat the extruded water 2, while the addition of an insulating material can slow and gentle the heating. A storage section 13 provided in the metal heating case 10 near the heat source can quickly heat the extruded water 2. The amount of steam generated, the time it takes to generate steam, and other factors can be set within an appropriate range, taking into account the internal volume of the heating case 10, the shape of the battery 1, and other factors. First, depending on the internal volume, shape, structure, and material of the heating case 10, more steam than is needed to forcibly expel the air inside the heating case 10 and reduce and maintain the oxygen concentration in the heating case. Furthermore, the time can be appropriately determined taking into consideration the time it takes for the air inside the exterior case of the battery 1 to flow out, depending on the form of the battery 1, for example, the presence or absence, shape, structure, material, and the like of the exterior case of the battery 1. The time it takes for the air inside the exterior case of the battery 1 to flow out to the heating case 10 is determined by the internal volume of the exterior case and the thermal conductivity characteristics of the exterior case, and so, for example, the time it takes for water vapor to be generated can be made longer for a battery with a large internal volume and an exterior case with poor thermal conductivity.

[0060] The extruded water 2 can be sprayed on the bottom surface (FIG. 1) of the heating case 10, the inner surfaces such as the sides, or the surface of the battery 1, for example, or placed in an open container with the liquid (liquid surface, water droplets) exposed. This extruded water 2 can be heated to quickly generate steam. The extruded water 2 can also be placed in, for example, a closed area, a water container 4 (FIG. 6), or a storage section 13 (FIGS. 7 and 8), or absorbed in a water absorber, without exposing part or all of the liquid. By selecting and combining any of these methods, the temperature rise of the extruded water 2, the time required for temperature rise, the timing of evaporation, and the amount of water vapor generated can be varied, thereby generating water vapor at different times, adjusting the amount of water vapor generated, and lengthening or shortening the time for water vapor generation. For example, in the initial stage, a large amount of steam is generated from the extruded water 2, filling the tank with steam and discharging the internal air, and the check valve 20 is used to efficiently reduce the oxygen concentration in a short period of time. Thereafter, the amount of steam generated or released is gradually reduced or adjusted to maintain a low oxygen concentration or further reduce the oxygen concentration. (water container 4)

[0061] The extruded water 2 can be placed in the water container 4 and placed inside the heating case 10. The movable water container 4 allows for easy placement of a predetermined amount of extruded water 2 at a predetermined location. The water container 4 can be placed, for example, on the bottom surface 10c, side surface 10b, or top surface 10a of the heating case 10, in contact with or adjacent to the battery 1, or in a predetermined position and orientation via a stand, connector, or the like. The shape, size, and structure of the water container 4 are not limited as long as it can hold the extruded water 2. The water container 4 may be, for example, a storage container or tray that is always open (Figure 2), or it may have a lid 4b that closes the opening 4a, a freely openable lid 4c, or a valve (Figure 6). The water container 4 has an opening 4a. Water can be supplied or poured into the water container 4 through the opening 4a, and the resulting steam generated by boiling can be released into the heating case 10. The water container 4 in Figure 2 has a large opening area, allowing for even generation and diffusion of steam. The opening 4a in FIG. 6 is provided with a water supply port and a steam release port separately.

[0062] The water container 4 may have a lid 4b that partially or completely closes the opening 4a. The lid 4c can be opened, for example, at a predetermined internal pressure or temperature within the water container 4. The lid 4c can be opened, for example, when the extruded water 2 boils or reaches a predetermined temperature, causing the internal pressure within the water container 4 to rise and exceed the predetermined internal pressure. In the water container 4 shown in Figure 6, the opening 4a is closed by the lid 4c that opens when the extruded water 2 boils. For example, the lid 4c that opens at a predetermined internal pressure can have the same configuration and structure as the check valve 20. The open / close lid 4b can be configured to control the timing of opening and closing, the opening area, opening shape, number of openings, opening time, opening direction, etc., and can determine the direction, travel, and amount of steam release, the region in the heating case 10 where steam is filled, the region and direction where steam is filled, and the time for steam to be generated and released can be determined. It can also be guided and directed to a certain region or direction, and the time for steam generation and release can be controlled and adjusted. The openable lid 4c, which opens when the temperature of the extruded water 2 is above the boiling point, can vigorously release and diffuse steam from the opening 4a of the water container 4, stirring the steam, increasing and equalizing the steam content, and contributing to the displacement and reduction of residual air inside. For example, multiple water containers 4 can generate steam at different times, or the openable lids 4c can release steam into the heating case 10 at different times, thereby lengthening the steam generation time. Alternatively, the water container 4 can have multiple compartments inside, and the multiple openable lids 4c can open the opening 4a at different internal pressures or temperatures. The extruded water 2 can be exposed by pouring it into the water container 4 and then spraying it. The member covering the opening 4a or the lid 4b can be made of a material that melts and breaks at a predetermined temperature, allowing the extruded water 2 to be released or the extruded water 2 to be supplied into the heating case 10. can. (Storage section 13)

[0063] The heating case 10 may have a storage section 13 for storing and disposing the extruded water 2. One or more storage sections 13 may be provided on the top surface 10a, side surface 10b, or bottom surface 10c of the heating case 10. The storage section 13 may be provided on the inner and / or outer surface of the heating case 10, or may be spaced apart from either surface. For example, the storage section 13 may be provided on the top lid 12 of the heating case 10. The heating case 10 of FIG. 7 has a top lid 12 that closes an opening that opens upward, and the top lid 12 has a storage section 13 for the extruded water 2. The top lid 12 has a communication opening 14 that connects the storage section 13 to the inside of the heating case 10, and water vapor generated from the extruded water 2 can flow into the heating case 10 through the communication opening 14. This heating case 10 can be closed by closing the top lid 12 after the battery 1 is stored therein, and the extruded water 2 can be disposed in a predetermined position at the same time. The storage section 13 of the top cover 12 in Figure 8 has an upper opening storage recess 13a provided in the top cover 12, and an opening / closing lid 13b that can be freely opened and closed to close the upper opening of the storage recess 13a. A steam communication opening 14 is provided on the side of the storage recess 13a. The heating case 10 in the figure can store extruded water 2 in the storage recess 13a of the top cover 12, and the heating case 10 can be closed by closing the top cover 12. Furthermore, the top cover 12 can store and place extruded water 2 in the storage recess 13a, and the opening / closing lid 13b can be opened to supply extruded water 2 to the storage recess 13a. The storage section 13 can be integral with the heating case 10 or can be removable. The storage section 13 and the water container 4 can be filled with extruded water 2 and placed inside the heating case 10, allowing it to be positioned in a predetermined position.

[0064] The extruded water 2 can be absorbed into a water absorbent material and placed in the device. The absorbent material, which has absorbed the extruded water 2, is heated in the heating case 10 to generate steam. A hydrophilic, water-retentive water absorbent material can easily absorb the extruded water 2 when brought into contact with water. The water absorption method is not specified; for example, water can be absorbed by sprinkling water on the absorbent material, immersing the absorbent material in water, or evenly absorbing water by spraying. The water absorbent material prevents dripping, is easy to handle, and allows for easy placement of a predetermined amount of extruded water 2. The amount and duration of steam generation can be adjusted, and the absorbent material can be inexpensive and disposable. Heat-resistant materials can be reused. The absorbed water is a safe, secure, and low-cost liquid. Porous materials with water absorption and water retention properties, such as sponge, resin, paper, ceramic, and natural stone, can be used as the water absorbent material. The amount of water absorption can be adjusted and specified by the type, composition, properties, composition, particle size, size, shape, and amount. The amount of steam generation can also be adjusted and specified by the amount of water supplied to the absorbent material. The amount of water absorption can be determined by the amount of water supplied, the difference in mass between when dry before absorbing water and after absorbing water, etc. The amount and time of water vapor generation can be adjusted by the amount of water absorption, water absorption rate, particle size, size, shape, mixing ratio, etc. In the water absorbent material, the extruded water 2 on the surface boils first and turns into steam, and then the extruded water 2 in the center gradually heats up and generates steam. The time to generate water vapor can be extended by increasing the particle size and size of the water absorbent material. The amount and time of water vapor generation can also be adjusted by mixing water absorbents of different sizes, particle sizes, and shapes. The water absorbent material can also be placed inside the storage unit 13 and water container 4.

[0065] Extruded water 2 is supplied to the heating case 10 at a predetermined temperature and timing, and the supplied extruded water 2 is converted into steam and the internal air can be discharged. The method for supplying the extruded water 2 is not specified, but for example, extruded water 2 can be supplied from insulated containers placed inside and outside the heating case 10, allowing steam to be generated at different times and the time for steam generation to be extended.

[0066] Both the battery 1 and the extruding water 2 can be placed inside the heating case 10, and the heating case 10 can be carried into the heat treatment furnace 3. The battery 1 and the extruding water 2 can be placed inside the heating case 10 at the same time, or the extruding water 2 can be placed inside the heating case 10 before and / or after the battery 1 is placed inside. The extruding water 2 can be safely and easily placed inside the heating case 10 before heating. In either case, no separate or dedicated water or steam supply device is required, which contributes to low equipment costs. Water is safe and can be procured at low cost, reducing running costs. Furthermore, placing the extruding water 2 inside the heating case 10 does not require a particularly large space, which contributes to the miniaturization of the heating case 10 and the heat treatment furnace 3.

[0067] When extruded water 2 was placed in heating case 10 and heated in heat treatment furnace 3, it was confirmed that the oxygen concentration of 21% when battery 1 was stored could be reduced to 10% or less, the combustion limit, with ample time before the heat treatment temperature of battery 1. The time it takes for the interior of heating case 10 to reach a low oxygen concentration varies depending on the heat treatment furnace 3, heating case 10, and capacity, size, and form of battery 1, but when multiple heating cases 10 measuring, for example, 110 cm in length, 170 cm in width, and 90 cm in height, were heated under different conditions, it was confirmed that the oxygen concentration reached 10% or less 3 to 8 minutes after steam generation began, and 3% or less 5 to 15 minutes later. When thermal runaway was caused in the battery 1 without the extruded water 2 (comparative example), a rapid temperature rise (from about 670°C to about 1,100°C) occurred due to thermal runaway, but when the extruded water 2 was placed in the heating case 10, it was confirmed that the temperature rise due to thermal runaway was prevented or suppressed, and heat treatment could be carried out within an appropriate heat treatment temperature range that allows high-quality valuables to be efficiently recovered. This confirmed that it is possible to prevent the melting of aluminum, for example (the melting point of aluminum is about 660°C), and improve the recovery rate of high-quality valuables. (Heat treatment furnace 3)

[0068] The heat treatment furnace 3 is not particularly limited and can be appropriately selected depending on the purpose as long as it has a heat source and can heat the heating case 10 to heat the battery 1. Any heat treatment furnace currently in use or that will be developed in the future can be used as the heat treatment furnace 3.

[0069] The heat treatment furnace 3 can heat one or more heating cases 10 placed inside. The heat treatment furnace 3 can heat-treat the batteries 1 by controlling the heating temperature to a set temperature. The heat treatment furnace 3 can, for example, detect the temperature inside the heat treatment furnace 3, the external or internal temperature of the heating case 10, and the temperature of the batteries 1 and control the temperature to a set temperature. The heat treatment furnace 3 can control the set temperature by controlling thermal energy so that the detected temperature falls within a preset temperature range. The heat treatment furnace 3 can also be provided with an exhaust treatment unit to exhaust the internal air inside the furnace and discharge the thermal energy of the batteries 1, thereby adjusting the temperature inside the heat treatment furnace and limiting temperature increases. The set temperature for heat-treating the batteries 1 is set to a temperature that allows high-quality valuables to be efficiently recovered after the batteries 1 are heated and heat-treated. If the set temperature is too low, the heat-treated batteries 1 cannot be separated into a state suitable for recovering valuables by crushing or pulverization, etc. Conversely, if the set temperature is too high, valuables cannot be recovered in a high-quality state. For example, if the set temperature is too low or the heat treatment time is too short, the separator, binder, etc. may not be sufficiently sintered, resulting in inefficient recovery of valuable materials and a lower evaluation of the recovered valuable materials. Furthermore, if the set temperature is too high, aluminum may melt at temperatures above 660°C, copper may oxidize at temperatures above 800°C to 1,000°C, and lithium may evaporate at temperatures above 900°C, potentially producing cobalt oxide. This may lower the evaluation of the recovered valuable materials and make it difficult to efficiently recover high-quality valuable materials. The heat treatment temperature at which high-quality valuable materials can be efficiently recovered is determined appropriately depending on the substances contained in the battery 1 and the valuable materials to be recovered. The set temperature at which the heat treatment furnace 3 heat-treats the battery 1 is preferably between 250°C and 550°C, for example, in the case of lithium-ion secondary batteries.

[0070] The temperature and time for heating and heat-treating the battery 1 vary depending on the type and structure of the battery 1, so the heat-treated battery 1 is crushed, pulverized, and sorted to confirm and identify a state in which valuable materials can be effectively recovered. For example, batteries with a plastic exterior film, such as lithium polymer secondary batteries, can be heat-treated with short heating times, while batteries with metal exterior cans can be heat-treated with longer heating times. Furthermore, the heat treatment time for a battery 1 that is separated into individual units differs from that for a battery unit in which multiple batteries 1 are housed in a metal exterior case. A single battery 1 can be heat-treated in a short time because the battery 1 is heated directly, but a battery 1 housed in an exterior case requires a longer heat treatment time because the battery 1 is heated through the exterior case.

[0071] A continuous furnace capable of efficiently heat-treating batteries 1 is suitable for the heat treatment furnace 3. A continuous furnace can continuously transport heating cases 10, efficiently heat-treat the batteries 1 placed in the heating cases 10, and efficiently recover valuable resources. A continuous furnace can heat-treat batteries 1 stored in heating cases 10 while transporting them, for example, on a heat-resistant belt conveyor. This continuous furnace has a closed structure that allows batteries 1 to pass through the inlet and outlet, and can maintain the internal temperature at a set temperature to continuously heat-treat batteries 1. Furthermore, a continuous furnace can also be used to heat-treat one or more heating cases 10 while transporting them in a container such as a pallet or tray. The pallet can be configured to have an opening at the top so that the batteries 1 can be exposed and heated and fired in the heat treatment furnace 3. This continuous furnace allows the pallet to be pushed and moved into the continuous furnace to heat-treat batteries 1. Furthermore, the pallet or heating case 10 can be moved by, for example, placing it on a cart, or by providing heat-resistant wheels on the bottom of the pallet or heating case 10, or by arranging multiple heat-resistant rollers in a parallel position to allow smooth movement.

[0072] The heat treatment method for heat treating batteries to recover valuable materials includes a battery carrying-in step of placing the batteries in a heating case 10, and a heat treatment step of heating the heating case 10 in a heat treatment furnace and heating the batteries inside through the heating case 10. The heat treatment step includes a pretreatment step of forcibly evacuating the air inside the heating case 10, and a heating step of heating the batteries. The method for recovering valuable materials from batteries further includes a recovery step of separating and recovering the valuable materials. [Battery 1 delivery process]

[0073] In the battery 1 loading process, the battery 1 is loaded into the heating case 10 and placed in a predetermined position. The extrusion water 2 is also loaded into the heating case 10. The extrusion water 2 is loaded into the heating case 10 at the same time as the battery 1, or before or after the battery 1 is placed. For example, after the battery 1 and extrusion water 2 are loaded into the heating case 10, the opening is closed with the top lid 12 of the heating case 10. When the top lid 12 is closed and sealed, internal air (initial air) exists within the heating case 10, and the oxygen concentration is the same as that of the outside air (e.g., 21%). The battery 1 loading process can be performed safely and securely in a short time at room temperature and normal pressure, ensuring low cost and safety. The heating case 10 containing the battery 1 and extrusion water 2 is loaded into the heat treatment furnace 3. [Heat treatment process]

[0074] In the battery 1 carrying-in step, the heating case 10 containing the battery 1 is placed in the heat treatment furnace 3, and the heating case 10 is heated in the heat treatment step. In the heat treatment step, the heating case 10 is heated in the heat treatment furnace 3, and the battery 1 contained therein is heated and heat-treated through the heating case 10. The heat treatment step includes a pretreatment step in which the air inside the heating case 10 is forcibly discharged, and a battery 1 heating step in which the battery 1 inside is heated and heat-treated through the heating case 10. The pretreatment step is an exhaust step in which the air inside is exhausted as pretreatment for the heat treatment of the battery 1. In the pretreatment step, the heating case 10 has extrusion water 2 that vaporizes itself to forcibly exhaust the air inside, and the extrusion water 2 is heated in the heating case 10, and the water vapor generated by heating exhausts the air inside. In the pretreatment process, the heated extruded water 2 vaporizes into water vapor. The low-density water vapor generated in the heating case 10 displaces the internal air. As the water vapor fills the heating case 10, it displaces the internal air through the exhaust opening 11 and is then discharged outside the heating case 10. As the internal air with a high oxygen concentration is discharged through the check valve 20, the amount of internal air remaining in the heating case 10 decreases, and the oxygen concentration drops. The pretreatment process creates and maintains a low-oxygen atmosphere within the heating case 10 below the flammability limit. In the battery 1 heating process, the battery 1 is heated and heat-treated via the heating case 10 in a state where the internal air has been discharged and the oxygen concentration has been reduced in the pretreatment process. This prevents an increase in internal temperature due to excessive thermal energy generated by the discharge ignition, even if the battery 1 heated in the heating case 10 experiences thermal runaway and ejects discharged materials. This prevents the battery 1 from being heat-treated within a set temperature range that is favorable for recovering valuable resources. In the heating process of the battery 1, the water vapor in the heating case 10 is further heated to generate superheated steam, which can efficiently heat and heat-treat the battery 1. The superheated steam can heat-treat the battery 1 even in a low-oxygen atmosphere.

[0075] The heat treatment process of the present disclosure includes a pretreatment process, which reduces the oxygen concentration in the heating case 10. The present disclosure has the advantage that heating (heat treatment), which may cause thermal runaway of the battery 1, is performed in the heating case 10 in a low-oxygen environment, thereby recovering high-quality valuables, improving recovery efficiency, and preventing damage to the heat treatment furnace 3 while ensuring operational safety. Heating the heating case 10 in the heat treatment furnace 3 initiates heating of the extruded water 2 and the battery 1 through the heating case 10, but the extruded water 2 vaporizes into water vapor at 100°C under atmospheric pressure. In contrast, the temperature at which thermal runaway of the battery 1 may occur is higher than this, at the heat treatment temperature at which the battery 1 is heat-treated. The pretreatment process can vaporize the extruded water 2 to generate water vapor at a low temperature range that does not cause thermal runaway of the battery 1. Therefore, the pretreatment process, which begins with the generation of water vapor and the forced exhaust of internal air as a pre-heat treatment step, creates a low-oxygen state within the heating case 10 below the combustion limit when heat-treating batteries 1 where thermal runaway is a concern. Even if the battery 1 were to experience thermal runaway and emit exhaust, the low-oxygen state prevents ignition and prevents or suppresses a rapid rise in internal temperature due to excessive thermal energy generated by ignition of the exhaust. Thermal runaway can occur irregularly from unspecified batteries 1, momentarily emitting high-temperature exhaust gases and rapidly raising the internal temperature, preventing heat treatment at a desirable temperature, including for other batteries 1 (battery cells), and inhibiting high-quality, effective, and efficient recovery of valuable resources. Thermal runaway also affects work safety and raises concerns about damage to the heat treatment furnace 3. However, the present disclosure avoids these adverse effects by including a pretreatment process in the heat treatment process, heat-treating the battery 1 within the heating case 10, and heat-treating the battery 1 in a low-oxygen state. [Recovery process]

[0076] The recovery process recovers valuable materials from the heat-treated batteries obtained by the heat treatment process. After a pretreatment process in which the internal air inside the heating case 10 is forcibly expelled, the heat-treated batteries 1 are heat-treated at an optimal temperature range to prevent abnormal temperature increases in the batteries 1 due to thermal runaway, creating a favorable recovery condition. This allows valuable materials to be recovered in a high-quality and efficient state in the recovery process. The recovery process can be appropriately selected depending on the purpose, such as the valuable materials to be recovered and the battery's configuration, form, and condition. For example, in the recovery process, after the heat treatment of the batteries 1 in the heat treatment process, the heat-treated batteries are removed from the heating case 10, and valuable materials are recovered using a dry or / and wet method. For example, specific valuable materials can be recovered from the heat-treated batteries (batteries 1) by crushing, pulverizing, sorting, separating, or classifying them, or a combination thereof. Furthermore, other processes can be added as needed, and one or more processes can be performed in stages. The present disclosure is characterized in that the heat treatment process for the battery includes a pretreatment process in which the air inside the heating case 10 is forcibly expelled with water vapor generated by extruded water 2, and does not specify a method or device for recovering valuable materials from a battery 1 that has been heat-treated by a heat treatment method, and all other methods and devices that can recover valuable materials from a heat-treated battery can be used. Not only currently used methods but also methods that will be developed in the future can be used.

[0077] The recovery process can include a crushing process and a separation process. Heat-treated batteries that have been heat-treated within the optimal temperature range are in a state suitable for crushing, separation, and recovery, and can be easily crushed and separated to recover valuable materials. This allows for high-quality valuable materials to be recovered, improving the efficiency of valuable material recovery. In the crushing process, the heat-treated batteries are crushed to obtain crushed material. The crushing process can be performed in stages, and the crushed material can be crushed into finer particles to obtain a pulverized material. In the separation process, valuable materials or materials containing valuable materials (e.g., black mass) are separated from the crushed material. In the separation process, black mass containing valuable materials or valuable materials are sorted, separated, and classified using, for example, sieves, magnetic force, wind force, centrifugal force, suction force, etc. The separation process can be performed in stages and can be appropriately selected depending on the purpose. For example, crushed materials such as coarse products and fine products can be classified according to size, and sorting can be performed using wind force, magnetic force, sieves, etc., or a combination of these, depending on the valuable materials to be recovered. The separation process can efficiently recover valuable materials from black mass containing at least one of non-ferrous metals, i.e., cobalt, nickel, lithium, copper, and aluminum, and can also efficiently recover these or any of them as valuable materials from batteries having copper foil or aluminum foil as the electrode core. [Industrial Applicability]

[0078] The present disclosure can be suitably used as a method for heat-treating a battery at an optimal temperature by suppressing a temperature rise due to thermal runaway of the battery during the heat treatment process, and as a valuable resource recovery method that can efficiently recover valuable resources in a high-quality state by heat-treating the battery using this heat treatment method. [Explanation of symbols]

[0079] 100...Battery heat treatment device 1...Battery 2...Extruded water 3...Heat treatment furnace 4…Water container 4a...Opening 4b…Lid 4c...Opening and closing lid 10...Heating case 10a…Top surface 10b...side 10c…Bottom surface 11...Exhaust opening 12...Top lid 13...Storage area 13a...Storage recess 13b…Opening / closing lid 14…Communication opening 20...Check valve 21...Valve body 21a...leaf spring 21b…spherical 21c...Bimetal 22...Valve seat 22a...Through hole 23…Discharge port 24...Spring 25...Threaded rod 26...Female screw hole 27...Blocking plate 28...Adjustment knob 29...Pressure plate

Claims

1. a battery loading step in which the batteries are placed in a closed but not sealed heated case; The heating case containing the battery in the carrying-in step is placed in a heat treatment furnace, Heating the heating case in the heat treatment furnace, a heat treatment step of heating the internal battery through the heating case, A heat treatment method for heat treating a battery from which valuables are recovered, comprising: The heat treatment step a pretreatment step of forcibly discharging the air inside the heating case and a heating step of the battery, In the pretreatment step, The heating case is provided with extrusion water that vaporizes itself and forcibly expels the internal air; The extruded water is heated in the heating case; The water vapor generated by heating expels the air inside, The heating case from which the internal air has been discharged in the pretreatment step is heated in the heating step, A battery heat treatment method for heat-treating a battery placed in the heating case to a state in which valuable materials can be recovered.

2. The method for heat treating a battery according to claim 1, The heating case includes: The internal air is passed through the exhaust direction, A check valve is provided to prevent gas from passing in the opposite direction. A method of heat treating batteries using a closed but not sealed metal case.

3. The method for heat treating a battery according to claim 2, The check valve is a valve body that is elastically deformed by the internal pressure of the heating case to open, The valve body elastically contacts the valve seat to close the valve, The method for heat treatment of a battery, wherein the valve body is pushed by the internal pressure of the heating case and separates from the valve seat to open the valve.

4. The method for heat treating a battery according to claim 2, The check valve is a heat-resistant valve body placed on the discharge opening of the heating case; The valve body comes into close contact with the valve seat by its own weight to close the valve, The method for heat treatment of a battery, wherein the valve body is pushed by the internal pressure of the heating case and separates from the valve seat to open the valve.

5. The method for heat treating a battery according to claim 1, In the pretreatment step, The battery and the extruded water are both placed inside the heating case, The battery heat treatment method includes carrying the heating case containing the battery and the extruded water into the heat treatment furnace.

6. The method for heat treating a battery according to claim 1, The heat treatment method for a battery includes placing the extruded water in a water container and placing the water container in the heating case.

7. The method for heat treating a battery according to claim 6, The water container is The heat treatment method for a battery includes a container in which the opening is closed with an openable lid that opens when the extruded water boils.

8. The method for heat treating a battery according to claim 1, the heating case has a top lid that closes an opening for inserting the battery, The top cover is A storage section for the extrusion water is provided, a communication opening is provided that communicates the storage section with the inside of the heating case, In the heat treatment step, The extrusion water in the storage section is heated in the heat treatment furnace, The method for heat treatment of a battery includes flowing the generated water vapor into the heating case through the communication opening to discharge the internal air.

9. The method for heat treating a battery according to claim 1, The extrusion water is poured onto the entire or almost entire bottom surface of the heating case, A method of heat treatment for batteries that uses evaporating water vapor to expel internal air.

10. The method for heat treating a battery according to claim 1, The extrusion water is poured into a plurality of locations in the heating case, A method of heat treatment for batteries that uses evaporating water vapor to expel internal air.

11. The method for heat treating a battery according to claim 1, In the heating case, Add the extrusion water in an amount equal to or greater than the internal volume (liters) of the heating case multiplied by 0.8 cc. The heat treatment method for a battery includes evaporating the extruded water to produce water vapor, which expels the internal air from the heating case.

12. The method for heat treating a battery according to claim 1, Supplying the extrusion water to the heating case, The method for heat treatment of a battery includes converting the supplied extruded water into steam and discharging the internal air.

13. The method for heat treating a battery according to claim 1, The method for heat treatment of a battery, wherein the battery is a lithium ion secondary battery.

14. a heat treatment step of performing heat treatment according to the heat treatment method of any one of claims 1 to 13; The heat-treated battery obtained in the heat treatment step is A method for recovering valuable materials from batteries, including a recovery step of crushing the batteries to separate and recover the valuable materials.

15. A method for recovering valuable materials from the battery according to claim 14, In the recovery step, Crushing the heat-treated battery A method for recovering valuable materials from batteries, comprising a separation step of separating black mass containing valuable materials from crushed material.

16. A method for recovering valuable materials from the battery according to claim 15, The black mass is A method for recovering valuable materials from batteries containing at least one non-ferrous metal selected from the group consisting of cobalt, nickel, and lithium.

17. A method for recovering valuable materials from the battery according to claim 14, The battery, A method for recovering valuable materials from batteries that use copper foil or aluminum foil as the electrode core.

18. A closed but not sealed heated case for the battery; a heat treatment furnace for heating the heating case, the heating case has extruded water; The extruded water in the heating case is heated by the heat treatment furnace, and the generated steam expels the internal air, The heating case from which the internal air has been discharged is heated by the heat treatment furnace, A battery heat treatment device that heat-treats the battery in the heating case to a state where valuables can be recovered.

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