Battery drying method and drying device

Abstract

The present application discloses a battery drying method and drying equipment. The battery drying method comprises: evacuating an oven; introducing carbon dioxide gas into the oven; performing a drying operation on the electrode assembly in the oven; and replacing the carbon dioxide gas in the oven after the drying operation is completed. The present application dries the battery in a closed oven filled with carbon dioxide gas. The oxygen content and nitrogen content in the oven are relatively low. The metallic lithium on the surface of the pole piece is not easy to react chemically with oxygen or nitrogen, nor with carbon dioxide gas, which reduces the consumption of lithium ions on the surface of the pole piece, facilitates more lithium ions to be embedded in the pole piece, and improves the lithium replenishment effect. After the drying operation is completed, the carbon dioxide gas in the closed oven is replaced, which can minimize the harm caused to the human body by carbon dioxide gas when opening the box to take out the electrode assembly.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular relates to a battery drying method and drying equipment. Background Art

[0002] Lithium-ion batteries have the advantages of large specific capacity, high operating voltage, long cycle life, high energy density, and low environmental pollution, and have been widely used in low-speed vehicles, power tools, energy storage and other fields. However, lithium loss will occur in the electrode materials of lithium-ion batteries during use, which limits the energy density of lithium-ion batteries and shortens the cycle life of lithium-ion batteries.

[0003] Adding metallic lithium to the surface of the battery's electrode is a feasible lithium replenishment solution. How to improve the battery's lithium replenishment effect is a research direction in the industry. Summary of the invention

[0004] The embodiments of the present application provide a battery drying method and drying equipment, which can improve the efficiency of lithium ion embedding into the electrode sheet and improve the lithium replenishment effect.

[0005] According to the first aspect of the present application, the present application provides a battery drying method, which includes: evacuating an oven; introducing carbon dioxide gas into the oven; performing a drying operation on the battery in the oven; and replacing the carbon dioxide gas in the oven after the drying operation is completed.

[0006] The embodiment of the present application dries the battery in a sealed oven filled with carbon dioxide gas. The oxygen content and nitrogen content in the oven are relatively low. The metal lithium on the surface of the pole piece is not easy to react chemically with oxygen or nitrogen, nor with carbon dioxide gas, which reduces the consumption of lithium ions on the surface of the pole piece, facilitates more lithium ions to be embedded in the pole piece, and improves the lithium replenishment effect. After the drying operation is completed, the carbon dioxide gas in the sealed oven is replaced, which can minimize the harm caused to the human body by the carbon dioxide gas when unpacking the battery.

[0007] In some embodiments, the oven is subjected to a vacuum treatment, including: extracting the air in the oven until the air pressure in the oven reaches a preset air pressure threshold; wherein the preset air pressure threshold is less than or equal to 5KPa. Thus, not only the air in the storage space of the oven can be extracted, but also the air in the pores or gaps of the battery itself can be extracted, which is beneficial to reduce the chemical reaction between the air in the pores or gaps of the battery itself and lithium, further improve the efficiency of lithium ion embedding into the pole piece, and improve the lithium replenishment effect.

[0008] In some embodiments, after stopping the vacuuming and before introducing carbon dioxide gas into the oven, the drying method further includes: obtaining the air pressure in the oven after a first preset time; if the air pressure in the oven is greater than a preset air pressure threshold, an alarm signal is issued. The alarm signal prompts relevant personnel that there is a fault in the oven, which facilitates timely maintenance and helps reduce the impact of equipment failure on the lithium replenishment effect of the electrode. After the first preset time, if the air pressure in the oven remains basically unchanged, it means that the air tightness of the oven is good and the subsequent processes can be performed normally.

[0009] In some embodiments, after carbon dioxide gas is introduced into the oven and before the drying operation is performed, the drying method further includes: obtaining the air pressure in the oven; stopping the introduction of carbon dioxide gas when the air pressure in the oven reaches atmospheric pressure. The oven can always maintain atmospheric pressure, and the accommodating space of the oven and the pores and gaps of the battery are filled with carbon dioxide gas, which is conducive to further reducing the consumption of lithium ions, improving the efficiency of lithium ion insertion, and also reducing the impact of the pressure in the oven on battery performance. Alternatively, after carbon dioxide gas is introduced into the oven and before the drying operation is performed, the drying method further includes: obtaining the concentration of carbon dioxide gas in the oven; stopping the introduction of carbon dioxide gas when the concentration of carbon dioxide gas in the oven reaches 95%. The oxygen concentration and nitrogen concentration in the oven are both lower than the lower limit value that can react chemically with metallic lithium, and the possibility of oxygen and nitrogen reacting chemically with metallic lithium is very small. At this time, stopping the introduction of carbon dioxide gas can save the amount of carbon dioxide gas, reduce costs, and reduce the possible harm caused by carbon dioxide gas.

[0010] In some embodiments, replacing the carbon dioxide gas in the oven includes: exhausting the carbon dioxide gas in the oven and simultaneously inputting the replacement gas into the oven; controlling the exhaust amount of the carbon dioxide gas and the input amount of the replacement gas so that the gas pressure in the oven is greater than the atmospheric pressure. In this way, the possibility of the replacement air re-entering the pores or gaps of the battery can be reduced, and the risk of at least part of the replacement gas reacting with the metallic lithium at high temperature can be reduced.

[0011] In some embodiments, the replacement gas includes air, which is harmless to the human body, easy to obtain, and low in cost.

[0012] In some embodiments, during the process of replacing the carbon dioxide gas in the oven, the gas pressure in the oven is greater than the atmospheric pressure and less than or equal to 105 KPa. Maintaining a slightly positive pressure in the oven is beneficial to reducing the risk of at least part of the replacement gas reacting with metallic lithium at high temperature, and can also improve operational safety and reduce the risk of personal injury.

[0013] In some embodiments, replacing the carbon dioxide gas in the oven includes: exhausting the carbon dioxide gas in the oven and simultaneously inputting replacement gas into the oven; detecting the concentration of the carbon dioxide gas in the oven; and stopping the replacement when the concentration of the carbon dioxide gas in the oven reaches a preset concentration threshold. In this way, the harm caused by the carbon dioxide gas to the human body when unpacking the battery can be reduced, and the risk of poisoning can be reduced.

[0014] In some embodiments, the preset concentration threshold is less than or equal to 0.04%. The concentration of carbon dioxide gas in the oven is close to the concentration of carbon dioxide gas in the external environment, which is conducive to reducing the discomfort of the human body after the oven is turned on and minimizing the impact on the human body.

[0015] In some embodiments, during the drying operation, the drying method further includes: obtaining the concentration of carbon dioxide gas in the oven; if the concentration of carbon dioxide gas in the oven is lower than the concentration before the drying operation is performed, an alarm signal is issued. If the concentration of carbon dioxide gas decreases, an alarm signal is issued in a timely manner, which can prompt relevant personnel that there is a fault in the oven, facilitate timely maintenance, and help reduce the impact of equipment failure on the lithium replenishment effect of the electrode and the physical harm to production personnel.

[0016] In some embodiments, the drying method further includes: after stopping replacing the carbon dioxide gas in the oven for a second preset time, issuing a prompt signal. After the ventilation is completed, there may still be some residual heat in the oven. Waiting for the second preset time before issuing the prompt signal is helpful to reduce the risk of residual heat in the oven being dissipated to the outside and causing harm to people.

[0017] In some embodiments, during the drying operation, the drying temperature is 60°C-100°C, which is beneficial to both increasing the rate of lithium ion embedding into the pole piece and reducing the adverse effect on the flexibility of the pole piece. And / or, the drying time is 1h-8h, which is beneficial to both increasing the amount of lithium ions embedded into the pole piece and reducing the adverse effect on the flexibility of the pole piece.

[0018] According to the second aspect of the present application, the present application also provides a drying device, which includes: an oven for accommodating batteries; a drying device for providing heat to the oven; a vacuum device for extracting gas from the oven; a ventilation duct connecting the inside and outside of the oven; a control valve provided in the ventilation duct for opening and / or blocking the ventilation duct; and a control device connected to the vacuum device and the control valve, and including a memory and a processor, the memory storing a computer program, and the processor being configured to execute the drying method provided in any embodiment of the first aspect of the present application through the computer program.

[0019] In some embodiments, the ventilation duct includes a first duct and a second duct that are separately arranged, one of which is used to circulate carbon dioxide gas, and the other is used to circulate replacement gas; the control valve is configured to selectively block the first duct and the second duct, or to conduct one of the first duct and the second duct. Carbon dioxide gas and replacement gas are two different gases, respectively. The first duct and the second duct for conveying carbon dioxide gas and replacement gas are two independent ducts, which facilitates the connection of the first duct and the second duct with other equipment, helps to simplify the drying process, and improves the drying efficiency.

[0020] In some embodiments, the drying device further includes: a first detection device for detecting the concentration of carbon dioxide gas in the oven; and / or a second detection device for detecting the gas pressure in the oven. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 A schematic flow chart of a battery drying method provided in the first embodiment of the present application.

[0023] Figure 2 A schematic flow chart of a battery drying method provided in the second embodiment of the present application.

[0024] Figure 3 A schematic flow chart of a battery drying method provided in the third embodiment of the present application.

[0025] Figure 4 A schematic flow chart of a battery drying method provided in the fourth embodiment of the present application.

[0026] Figure 5 A schematic flow chart of a battery drying method provided in the fifth embodiment of the present application.

[0027] Figure 6 A schematic diagram of the structure of a drying device provided in some embodiments of the present application.

[0028] Figure 7 A structural block diagram of a drying device provided in some embodiments of the present application.

[0029] In the attached figure:

[0030] Drying equipment 1, oven 10, drying device 20, vacuum device 30, vacuum pump 31, exhaust pipe 32, ventilation pipe 40, first pipe 41, second pipe 42, control valve 50, control device 60, memory 61, processor 62, computer program 63, second detection device 70, first detection device 80. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0032] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0033] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0034] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0036] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0037] The term “plurality” used in this application refers to two or more (including two).

[0038] In the embodiments of the present application, "parallel" includes not only the absolutely parallel situation, but also the roughly parallel situation conventionally recognized in engineering; at the same time, "vertical" includes not only the absolutely vertical situation, but also the roughly vertical situation conventionally recognized in engineering.

[0039] Lithium-ion batteries have the advantages of large specific capacity, high operating voltage, long cycle life, high energy density, and low environmental pollution, and have been widely used in low-speed vehicles, power tools, energy storage and other fields. However, the electrode material of lithium-ion batteries forms a solid electrolyte membrane (SEI membrane) during the first charge and discharge process. The resulting lithium loss limits the energy density of lithium-ion batteries, and the irreversible loss of active lithium during the cycle process will shorten the cycle life of lithium-ion batteries.

[0040] Adding metallic lithium to the surface of the electrode of a lithium-ion battery is a relatively effective lithium replenishment solution.

[0041] The whole process of lithium-ion battery manufacturing is extremely strict in controlling moisture. The moisture content inside the battery before sealing has a great impact on the electrochemical performance, life and reliability of the battery. Usually, the moisture content of the positive electrode, negative electrode and diaphragm in the battery before sealing is required to be below 200ppm to ensure good performance of the battery. At present, one of the heat transfer methods of the oven for battery baking is to transfer heat by heat conduction. The heating plate is in direct contact with the heated battery to transfer heat directly to the battery. The above-mentioned oven is used for baking. The main baking process is to use breathing baking. First, the moisture in the battery is baked out by heating, so that the moisture is freed to the cavity of the oven, and the moisture in the cavity is discharged out of the oven by vacuuming, and then the cavity is filled by introducing dry nitrogen. Repeat the above process 6 to 12 times to bake the moisture to the required range. Due to the increase of lithium metal, the traditional breathing method passes oxygen or nitrogen, and metallic lithium reacts with oxygen or nitrogen to form lithium nitride, which reduces the lithium effect and has the risk of lithium precipitation.

[0042] In view of this, the embodiment of the present application provides a technical solution, which dries the battery in a sealed oven filled with carbon dioxide gas. The oxygen content and nitrogen content in the oven are relatively low, and the metal lithium on the surface of the pole piece is not easy to react chemically with oxygen or nitrogen, nor with carbon dioxide gas, which reduces the consumption of lithium ions on the surface of the pole piece, facilitates more lithium ions to be embedded in the pole piece, and improves the lithium replenishment effect. After the drying operation is completed, the carbon dioxide gas in the sealed oven is replaced, which can minimize the harm caused by carbon dioxide gas to the human body when opening the box to take out the electrode assembly.

[0043] The technical solution provided in the embodiments of the present application is applicable to a battery drying method and drying equipment.

[0044] The battery in the embodiment of the present application is an unsealed battery, that is, the battery drying method provided in the embodiment of the present application is performed before the battery sealing liquid injection port is sealed.

[0045] The battery drying method and drying device of the present application are described below in conjunction with the accompanying drawings.

[0046] An embodiment of the present application provides a battery drying method. Figure 1 This is a schematic diagram of the process of the battery drying method provided in the first embodiment of the present application. Figure 1 , the battery drying method provided in the embodiment of the present application includes:

[0047] Step S10, vacuumizing the oven;

[0048] Step S30, introducing carbon dioxide gas into the oven;

[0049] Step S50, performing a drying operation on the batteries in the oven; and

[0050] Step S70, after the drying operation is completed, the carbon dioxide gas in the oven is replaced.

[0051] The battery in the embodiment of the present application includes an electrode assembly, the electrode assembly includes a first pole piece and a second pole piece with opposite polarities, and a diaphragm disposed between the first pole piece and the second pole piece, the diaphragm insulating the first pole piece and the second pole piece. The first pole piece includes a first current collector and a first active material layer coated on the surface of the first current collector. The second pole piece includes a second current collector and a second active material layer coated on the surface of the second current collector.

[0052] In some examples, the first pole piece and the second pole piece are wound and arranged. In other examples, there are multiple first pole pieces and multiple second pole pieces, and the multiple first pole pieces and the multiple second pole pieces are alternately stacked.

[0053] The oven has a relatively closed accommodation space for accommodating the batteries to be dried. In order to maintain the airtightness of the oven during the entire drying process, infrared or other suitable heating devices may be used as heat sources to provide heat to the oven so as to perform the drying operation. Optionally, the heating device may be disposed in the oven.

[0054] Before the oven is vacuumed, the battery to be dried may be placed in the oven. It should be noted that the electrode of the battery to be dried may be a electrode that has been supplemented with lithium. Exemplarily, the electrode may be supplemented with lithium by placing a lithium belt on the surface of the electrode or by other suitable means.

[0055] Optionally, the air in the oven may be extracted by a vacuum pump or other suitable vacuum extraction device to form a vacuum environment in the oven.

[0056] In the embodiment of the present application, replacing the carbon dioxide gas in the oven refers to replacing the carbon dioxide gas in the oven with other gases.

[0057] In the embodiment of the present application, the oven is first vacuumed, and then carbon dioxide gas is introduced into the oven, which can improve the air removal efficiency in the oven, reduce the consumption of carbon dioxide gas, and improve the drying efficiency. After the oven is filled with carbon dioxide gas (the concentration of carbon dioxide gas can reach a certain level, and the concentration of carbon dioxide gas is not required to be 100%), the oxygen content and nitrogen content in the oven are relatively low. At this time, the battery in the oven is dried. During the drying process, the metallic lithium on the surface of the pole piece is not easy to react chemically with oxygen or nitrogen, nor with carbon dioxide gas, which reduces the consumption of lithium ions on the surface of the pole piece, which is conducive to more and faster embedding of lithium ions into the pole piece at high temperature, and improves the lithium replenishment effect.

[0058] After the drying operation is completed, the carbon dioxide gas in the sealed oven is replaced to minimize the harm caused to the human body by the carbon dioxide gas when unpacking the battery.

[0059] In some embodiments, the oven is subjected to a vacuum treatment, which may specifically include:

[0060] The air in the oven is extracted until the air pressure in the oven reaches a preset air pressure threshold; wherein the preset air pressure threshold is less than or equal to 5KPa.

[0061] In the embodiments of the present application, unless otherwise specified, the air pressure in the oven refers to the absolute air pressure in the oven.

[0062] Specifically, during the vacuuming process, the absolute air pressure in the oven can be obtained in real time or periodically. When the absolute air pressure in the oven reaches a preset pressure threshold, the extraction of air in the oven is stopped.

[0063] Optionally, the preset air pressure threshold may be 5 KPa, 4.5 KPa, 4 KPa, 3.5 KPa or 3 KPa, etc.

[0064] The active material layer of the electrode has a porous structure. There will be air in the pores of the active material layer and in the gaps between the electrodes after the electrodes are wound or stacked. Under high temperatures, this part of air can directly react chemically with the metallic lithium on the surface of the electrode, resulting in lithium consumption.

[0065] The embodiment of the present application pumps the air pressure in the oven to less than or equal to 5KPa, which can not only pump out the air in the storage space of the oven, but also pump out the air in the pores or gaps of the battery itself, which is beneficial to reduce the chemical reaction between the air in the pores or gaps of the battery itself and lithium, further improve the efficiency of lithium ion embedding into the electrode, and improve the lithium replenishment effect.

[0066] Figure 2 A schematic diagram of a battery drying method provided in the second embodiment of the present application. Figure 2 After stopping the vacuuming and before introducing the carbon dioxide gas into the oven, the drying method of the embodiment of the present application further includes:

[0067] Step S21, obtaining the air pressure in the oven after a first preset time period; and

[0068] Step S22, determining whether the air pressure in the oven is greater than a preset air pressure threshold; if so, proceeding to step S23; if not, proceeding to step S30;

[0069] Step S23, sending an alarm signal.

[0070] Optionally, the first preset duration may be any value between 3 minutes and 8 minutes.

[0071] Optionally, the alarm signal may include a light signal, a sound signal or other signals capable of serving as a warning.

[0072] After stopping the vacuum pumping, the pressure is maintained for the first preset time. After the first preset time, if the air pressure in the oven increases, it means that there may be air leakage in the oven. The alarm signal will remind the relevant personnel that there is a fault in the oven, which is convenient for timely maintenance and helps to reduce the impact of equipment failure on the lithium replenishment effect of the electrode. After the first preset time, if the air pressure in the oven remains basically unchanged, it means that the air tightness of the oven is good and the subsequent processes can be carried out normally.

[0073] Figure 3 A schematic diagram of a battery drying method according to the third embodiment of the present application. Figure 3After the carbon dioxide gas is introduced into the oven and before the drying operation is performed, the drying method of the embodiment of the present application further includes:

[0074] Step S41, obtaining the air pressure in the oven; and

[0075] Step S42, when the air pressure in the oven reaches atmospheric pressure, the introduction of carbon dioxide gas is stopped.

[0076] When the air pressure in the oven reaches atmospheric pressure, the air pressure inside and outside the oven is balanced. During the drying process of the battery, the oven can always maintain atmospheric pressure, and the accommodating space of the oven and the pores and gaps of the battery are filled with carbon dioxide gas, which is beneficial to further reduce the consumption of lithium ions, improve the efficiency of lithium ion insertion, and reduce the impact of the pressure in the oven on battery performance.

[0077] Figure 4 This is a flow chart of a battery drying method provided in the fourth embodiment of the present application. In other embodiments, after the carbon dioxide gas is introduced into the oven and before the drying operation is performed, the drying method of the embodiment of the present application further includes:

[0078] Step S41', obtaining the concentration of carbon dioxide gas in the oven; and

[0079] Step S42', when the concentration of carbon dioxide gas in the oven reaches 95%, the introduction of carbon dioxide gas is stopped.

[0080] When the concentration of carbon dioxide gas in the oven reaches 95%, the oxygen concentration and nitrogen concentration in the oven are both lower than the lower limit that can produce chemical reactions with metallic lithium. The possibility of oxygen and nitrogen producing chemical reactions with metallic lithium is very small. At this time, stopping the introduction of carbon dioxide gas can save the amount of carbon dioxide gas, reduce costs, and reduce the possible harm caused by carbon dioxide gas.

[0081] In some embodiments, replacing carbon dioxide gas in the oven includes:

[0082] Exhausting the carbon dioxide gas in the oven and simultaneously inputting replacement gas into the oven; and

[0083] The exhaust rate of carbon dioxide gas and the input rate of replacement gas are controlled so that the gas pressure in the oven is greater than the atmospheric pressure.

[0084] Optionally, the replacement gas may be one or more of air, oxygen, nitrogen or other harmless gases.

[0085] The exhaust of carbon dioxide gas and the input of replacement gas can be carried out simultaneously to reduce the pressure change in the oven and reduce the impact on battery performance.

[0086] During the replacement process, the air pressure in the oven can be obtained in real time or periodically to adjust the exhaust amount of carbon dioxide gas and the input amount of replacement gas, so that the air pressure in the oven is dynamically maintained to be greater than the atmospheric pressure. For example, when the air pressure in the oven is greater than the atmospheric pressure, the valve opening of the carbon dioxide gas can be appropriately increased and / or the valve opening of the replacement gas can be reduced; when the air pressure in the oven is less than the atmospheric pressure, the valve opening of the replacement gas can be appropriately increased and / or the valve opening of the carbon dioxide gas can be reduced.

[0087] During the process of displacing the carbon dioxide gas in the oven, the gas pressure in the oven is always greater than the atmospheric pressure, which can reduce the possibility of the displaced air re-entering the pores or gaps of the battery and reduce the risk of at least part of the displaced gas reacting with metallic lithium at high temperature.

[0088] In some embodiments, the replacement gas includes air.

[0089] Air is harmless to the human body, easy to obtain and low in cost.

[0090] In some embodiments, during the process of replacing the carbon dioxide gas in the oven, the gas pressure in the oven is greater than the atmospheric pressure and less than or equal to 105 KPa.

[0091] Optionally, the gas pressure in the oven may be 102 KPa, 103 KPa, 104 KPa or 105 KPa, etc.

[0092] If the air pressure in the oven is too high, it is easy to injure operators or other equipment when opening the box to take out the battery. Therefore, during the process of replacing the carbon dioxide gas in the oven, the air pressure in the oven is slightly greater than the atmospheric pressure, and a slight positive pressure is maintained in the oven, which is beneficial to reduce the risk of at least part of the replaced gas reacting with metallic lithium at high temperature, and can also improve operational safety and reduce the risk of personal injury.

[0093] In some embodiments, replacing carbon dioxide gas in the oven includes:

[0094] Exhaust the carbon dioxide gas in the oven and simultaneously input replacement gas into the oven;

[0095] detecting the concentration of carbon dioxide gas in the oven; and

[0096] When the concentration of carbon dioxide gas in the oven reaches a preset concentration threshold, replacement is stopped.

[0097] Optionally, the preset concentration threshold may be a concentration that does not cause significant harm to the human body. For example, the preset concentration threshold may be less than 1%.

[0098] The embodiment of the present application detects the concentration of carbon dioxide gas in the oven and stops replacing it only after the concentration of carbon dioxide gas drops to a safe preset concentration threshold, thereby reducing the harm caused by carbon dioxide gas to the human body when unpacking the battery and reducing the risk of poisoning.

[0099] In some embodiments, the preset concentration threshold is less than or equal to 0.04%.

[0100] Optionally, the preset concentration threshold may be greater than or equal to the concentration of carbon dioxide gas in the air. In this case, the replacement gas may include air alone, which is beneficial to further reduce costs.

[0101] Exemplarily, the preset concentration threshold may be 0.036%, 0.037%, 0.038%, 0.039% or 0.04%, etc.

[0102] In the embodiment of the present application, the concentration of carbon dioxide gas in the oven is controlled within a range less than or equal to 0.04%. The concentration of carbon dioxide gas in the oven is close to the concentration of carbon dioxide gas in the external environment, which is beneficial to reducing the discomfort of the human body after the oven is opened and minimizing the impact on the human body.

[0103] In some embodiments, during the drying operation, the drying method of the embodiment of the present application further includes:

[0104] Obtaining the concentration of carbon dioxide gas in the oven;

[0105] If the concentration of carbon dioxide gas in the oven is lower than the concentration before the drying operation is performed, an alarm signal is issued.

[0106] If the concentration of carbon dioxide gas in the oven is lower than the concentration before the drying operation, it means that there may be a leak in the oven. During the drying operation, if the oven leaks, air will enter the oven, and the oxygen and nitrogen concentrations in the oven will increase. Oxygen and / or nitrogen may react chemically with metallic lithium, causing lithium ion consumption and affecting the lithium replenishment effect of the electrode. In addition, the carbon dioxide gas leaked from the oven will be directly emitted into the production workshop, affecting the health of the personnel in the production workshop.

[0107] To this end, the embodiment of the present application continuously monitors the concentration of carbon dioxide gas in the oven during the drying operation. If the concentration of carbon dioxide gas decreases, an alarm signal is promptly issued to prompt relevant personnel that there is a fault in the oven, which facilitates timely maintenance and helps reduce the impact of equipment failure on the lithium replenishment effect of the electrode and the physical harm to production personnel.

[0108] Optionally, the alarm signal may include a light signal, a sound signal or other signals capable of serving as a warning.

[0109] Figure 5A schematic diagram of a battery drying method provided in the fifth embodiment of the present application. Figure 5 , the drying method of the embodiment of the present application further includes:

[0110] Step S90, after stopping replacing the carbon dioxide gas in the oven for a second preset time, a prompt signal is issued.

[0111] Optionally, the second preset time length may be any value between 3 minutes and 10 minutes.

[0112] Optionally, the prompt signal may be a light signal, a sound signal or other signal that can serve as a prompt to remind relevant personnel that the drying of the batteries has been completed and the batteries can be unpacked and taken out.

[0113] The prompt signal is different from the alarm signal, so as to distinguish the two signals with different functions.

[0114] After the ventilation is completed, there may still be some residual heat in the oven. Waiting for the second preset time before issuing a reminder signal can help reduce the risk of residual heat in the oven being dissipated to the outside and causing personal injury.

[0115] In some embodiments, in the drying operation, the drying temperature is 50°C-90°C.

[0116] Optionally, the drying temperature may be 50°C, 60°C, 70°C, 80°C or 90°C, etc.

[0117] If the drying temperature is too low, the migration speed of lithium ions is limited, affecting the rate at which lithium ions are embedded in the electrode; if the drying temperature is too high, the electrode tends to become brittle and its flexibility deteriorates. In the embodiment of the present application, the drying temperature is set to 50°C-90°C, which is beneficial to both increasing the rate at which lithium ions are embedded in the electrode and reducing the adverse effect on the flexibility of the electrode.

[0118] In some embodiments, in the drying operation, the drying time is 1 hour to 7 hours.

[0119] Alternatively, the drying time may be 1 h, 2 h, 3 h, 4 h, 5 h, 6 h or 7 h.

[0120] If the drying time is too short, the time for lithium ions to be embedded in the electrode is too short, which affects the total amount of lithium ions embedded; if the drying time is too long, the electrode is subjected to high-temperature baking for a long time, which will also affect its flexibility. In the embodiment of the present application, the drying time is set to 1h-7h, which is beneficial to increase the amount of lithium ions embedded in the electrode and reduce the adverse effect on the flexibility of the electrode.

[0121] The battery drying method provided in the embodiment of the present application can be applied to drying equipment.

[0122] Figure 6A schematic diagram of the structure of a drying device provided in some embodiments of the present application, Figure 7 This is a structural block diagram of a drying device provided in some embodiments of the present application. Figure 6 and Figure 7 The drying equipment 1 provided in the embodiment of the present application includes an oven 10, a drying device 20, a vacuum device 30, a ventilation duct 40, a control valve 50 and a control device 60. The oven 10 is used to accommodate batteries. The drying device 20 is used to provide heat to the oven 10. The vacuum device 30 is used to extract gas from the oven 10. The ventilation duct 40 connects the inside and outside of the oven 10. The control valve 50 is provided in the ventilation duct 40, and is used to open and / or block the ventilation duct 40. The control device 60 is connected to the vacuum device 30 and the control valve 50. The control device 60 includes a memory 61 and a processor 62, and the memory 61 stores a computer program 63, and the processor 62 is configured to execute the drying method provided according to any embodiment of the present application through the computer program 63.

[0123] A sealed accommodation space is defined in the oven 10, and the accommodation space is used to accommodate batteries.

[0124] The drying device 20 may provide heat to the oven 10 by heat radiation, heat transfer or other suitable means.

[0125] Optionally, the drying device 20 may be an infrared heating device, which releases heat and transfers the heat to the containing space of the oven 10 when powered on.

[0126] Optionally, the drying device 20 may be disposed in the accommodating space to improve heat transfer efficiency and reduce heat loss.

[0127] The vacuum device 30 is used to extract the air in the oven 10 during the vacuum operation, and to extract the carbon dioxide gas in the oven 10 during the ventilation operation.

[0128] The vacuum pump 30 may include a vacuum pump 31 and an exhaust pipe 32, wherein the vacuum pump 31 is connected to the accommodation space in the oven 10, and the exhaust pipe 32 may extend from the vacuum pump 31 to the outside of the oven 10 to transport the gas extracted by the vacuum pump 31. Optionally, the exhaust pipe 32 may extend to the external environment outside the production workshop where the drying device 1 is located.

[0129] The vacuum pump 31 may be signal-connected to the control device 60 so as to operate under the control of the control device 60 .

[0130] The ventilation duct 40 is used to transport carbon dioxide gas and replacement gas into the oven 10. The ventilation duct 40 may include one duct or a plurality of independent ducts.

[0131] The control valve 50 may be a solenoid valve, or a mechanical valve or other suitable valve structures.

[0132] The control valve 50 may be connected to the control device 60 by signal so as to be opened, closed or adjust the opening degree under the control of the control device 60. For example, during the vacuuming process, the control valve 50 is closed under the control of the control device 60 to completely block the ventilation duct 40; during the process of introducing carbon dioxide gas into the oven 10, the control valve 50 is opened under the control of the control device 60; during the ventilation process, the control device 60 dynamically adjusts the opening degree of the control valve 50 so as to maintain a slightly positive pressure environment in the oven 10.

[0133] In some embodiments, the ventilation pipe 40 includes a first pipe 41 and a second pipe 42 which are separately arranged, one of which is used to circulate carbon dioxide gas, and the other is used to circulate replacement gas. The control valve 50 is configured to selectively block the first pipe 41 and the second pipe 42, or to conduct one of the first pipe 41 and the second pipe 42.

[0134] One end of the first pipe 41 and the second pipe 42 are both connected to the accommodation space of the oven 10, and the other end can extend to different positions outside the oven 10. For example, the pipe for circulating carbon dioxide gas is connected to the carbon dioxide gas generating device, and the pipe for circulating replacement gas can be directly connected to the external environment.

[0135] In some examples, the control valve 50 may include a valve body, and the first pipeline 41 and the second pipeline 42 may be connected to different interfaces of the valve body. In other examples, the control valve 50 may also include two valve bodies, which are respectively disposed in the first pipeline 41 and the second pipeline 42.

[0136] During the vacuuming process, the control valve 50 closes both the first pipe 41 and the second pipe 42; during the introduction of carbon dioxide gas into the oven 10, the control valve 50 only opens one of the first pipe 41 and the second pipe 42; during the ventilation process, the control valve 50 only opens the other of the first pipe 41 and the second pipe 42.

[0137] For example, the control valve 50 may be a two-position three-way valve.

[0138] Carbon dioxide gas and replacement gas are two different gases. The first pipeline 41 and the second pipeline 42 for conveying carbon dioxide gas and replacement gas are two independent pipelines, which facilitates the connection of the first pipeline 41 and the second pipeline 42 with other equipment, helps to simplify the drying process and improve the drying efficiency.

[0139] In some embodiments, the drying device 1 further includes a first detection device 80 , which is used to detect the concentration of carbon dioxide gas in the oven 10 .

[0140] Optionally, the first detection device 80 may be disposed in the accommodation space within the oven 10. The first detection device 80 may include at least one gas concentration sensor.

[0141] In some embodiments, the drying device 1 further includes a second detection device 70 , and the second detection device 70 is used to detect the air pressure in the oven 10 .

[0142] Optionally, the second detection device 70 may be disposed in the accommodation space in the oven 10. The second detection device 70 may include at least one air pressure sensor.

[0143] The present application provides a battery drying method, which includes:

[0144] The oven is vacuumed until the pressure inside the oven is less than or equal to 5KPa;

[0145] After stopping the vacuum pumping, the pressure is maintained for 5 minutes. If the air pressure in the oven does not change, carbon dioxide gas is introduced into the oven until the air pressure in the oven reaches the atmospheric pressure or the concentration of carbon dioxide gas reaches 95%; if the air pressure in the oven changes, an alarm signal is issued;

[0146] Perform drying operation on the batteries in the oven; during the drying operation, if the concentration of carbon dioxide gas changes, an alarm signal is issued;

[0147] After the drying operation is completed, the carbon dioxide gas in the oven is replaced by air. During the replacement process, the air pressure in the oven is maintained greater than the atmospheric pressure and less than 105KPa;

[0148] When the concentration of carbon dioxide gas in the oven is less than or equal to 0.04%, the replacement stops. After the replacement stops, a prompt signal is issued after a period of rest.

[0149] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery drying method, characterized in that: include: Evacuate the oven; introducing carbon dioxide gas into the oven; performing a drying operation on the electrode assembly in the oven; as well as After the drying operation is completed, replacing the carbon dioxide gas in the oven; After the carbon dioxide gas is introduced into the oven and before the drying operation is performed, the drying method further comprises: obtaining the gas pressure in the oven; stopping the introduction of carbon dioxide gas when the gas pressure in the oven reaches atmospheric pressure; or, Obtaining the concentration of carbon dioxide gas in the oven; and stopping the introduction of carbon dioxide gas when the concentration of carbon dioxide gas in the oven reaches 95%; The replacing of the carbon dioxide gas in the oven comprises: Exhausting the carbon dioxide gas in the oven and simultaneously inputting replacement gas into the oven; The exhaust rate of carbon dioxide gas and the input rate of replacement gas are controlled so that the gas pressure in the oven is greater than the atmospheric pressure.

2. The battery drying method according to claim 1, characterized in that: The step of vacuuming the oven comprises: Extracting air from the oven until the air pressure in the oven reaches a preset air pressure threshold; Wherein, the preset air pressure threshold is less than or equal to 5KPa.

3. The battery drying method according to claim 2, characterized in that: After stopping the vacuuming and before introducing the carbon dioxide gas into the oven, the drying method further comprises: After a first preset time period, obtaining the air pressure in the oven; If the air pressure in the oven is greater than the preset air pressure threshold, an alarm signal is issued.

4. The battery drying method according to claim 1, characterized in that: The replacement gas includes air.

5. The battery drying method according to claim 1, characterized in that: During the process of replacing the carbon dioxide gas in the oven, the gas pressure in the oven is greater than the atmospheric pressure and less than or equal to 105 KPa.

6. The battery drying method according to claim 1, characterized in that: The replacing of the carbon dioxide gas in the oven comprises: Exhausting the carbon dioxide gas in the oven and simultaneously inputting replacement gas into the oven; detecting the concentration of carbon dioxide gas in the oven; and When the concentration of the carbon dioxide gas in the oven reaches a preset concentration threshold, the replacement is stopped.

7. The battery drying method according to claim 6, characterized in that: The preset concentration threshold is less than or equal to 0.04%.

8. The battery drying method according to claim 1, characterized in that: In the drying operation, the drying method further comprises: Obtaining the concentration of carbon dioxide gas in the oven; If the concentration of the carbon dioxide gas in the oven is lower than the concentration before the drying operation is performed, an alarm signal is issued.

9. The battery drying method according to claim 1, characterized in that: Also includes: After the replacement of the carbon dioxide gas in the oven is stopped for a second preset time period, a prompt signal is issued.

10. The battery drying method according to claim 1, characterized in that: In the drying operation, the drying temperature is 50° C.-90° C., and / or the drying time is 1 h-7 h.

11. A drying device, characterized in that: include: an oven for housing the electrode assembly; A drying device for providing heat to the oven; A vacuum device for extracting gas from the oven; A ventilation duct connecting the inside and the outside of the oven; A control valve, provided in the ventilation duct, for opening or blocking the ventilation duct; as well as A control device is connected to the vacuum device and the control valve, and includes a memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the battery drying method according to any one of claims 1 to 10 through the computer program.

12. The drying device according to claim 11, characterized in that: The ventilation pipeline includes a first pipeline and a second pipeline which are separately arranged, wherein one of the first pipeline and the second pipeline is used for circulating carbon dioxide gas, and the other is used for circulating replacement gas; The control valve is configured to selectively block the first pipeline and the second pipeline, or to open one of the first pipeline and the second pipeline.

13. The drying device according to claim 11 or 12, characterized in that: The drying equipment also includes: a first detection device, used to detect the concentration of carbon dioxide gas in the oven; and / or The second detection device is used to detect the air pressure in the oven.

Images