Staged flowing type vacuumizing water removal method for battery

Abstract

The invention relates to the technical field of water removal and drying of a battery, in particular to a staged flowing type vacuum-pumping water removal method for the battery, and compared with a traditional vacuum-pumping water removal mode, the method can avoid the situation that vacuum needs to be pumped again after a large number of water molecules return to the battery again during pressure relief in the baking process. Therefore, the overall drying time of the battery is shortened, the battery dewatering efficiency is improved, the drying gas consumption is reduced, and the product quality is improved.

Description

Technical Field

[0001] The invention relates to the technical field of battery dehydration and drying, and in particular to a battery staged flow-type vacuum dehydration method. Background Art

[0002] In the production process of lithium batteries, the dehydration and drying process of lithium batteries is a key step that affects the quality of lithium batteries. If the lithium battery is not fully dried, the electrolyte in the battery will react with water to generate trace amounts of harmful gases, which will have an adverse effect on the environment of the injection room. It will also affect the quality of the electrolyte itself, resulting in poor battery performance and rusting of battery rivets. For this reason, lithium batteries need to be dehydrated and dried to avoid the impact of moisture on lithium batteries and the injection environment.

[0003] In the prior art, the traditional method for dehydrating and drying batteries is to place the batteries in a vacuum chamber and heat them by convection heating, and then remove the moisture inside the vacuum chamber by vacuuming to complete the battery dehydration and drying process. When the pressure is released during the heating process, the water molecules that are about to be precipitated from the battery in the original high vacuum state return to the battery cell for a second time, which can easily lead to insufficient drying of the battery. The vacuuming process still needs to be repeated, thereby extending the overall drying time of the battery, making it difficult to achieve the ideal battery dehydration and drying efficiency, which needs to be solved urgently. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present application provides a battery staged flow-type vacuum pumping and water removal method.

[0005] The above invention objectives of the present application are achieved through the following technical solutions:

[0006] A battery staged flow vacuum dewatering method comprises the following steps:

[0007] S1, placing the battery into the vacuum chamber, and heating the battery until the battery reaches a set temperature value or a set time;

[0008] S2, evacuating the inside of the vacuum chamber by a vacuum pump, and in the process of evacuating the inside of the vacuum chamber, monitoring the vacuum degree of the inside of the vacuum chamber in real time by a detection device and calculating the rate of change of the vacuum degree in real time;

[0009] S3. Set a supplementary program. When the rate of change of the vacuum degree is less than or equal to V1, record the vacuum degree at this time as A1, maintain the vacuum state, open the air intake proportional valve, allow the dry gas to enter the vacuum chamber through the air intake proportional valve, and adjust the opening of the air intake proportional valve so that the air flow inside the vacuum chamber is maintained within the range of vacuum degree (1-x)A1 to (1+x)A1. After maintaining the time t1, close the air intake proportional valve;

[0010] S4, when the rate of change of vacuum degree is less than (V1-a n ), record the vacuum degree as A n , maintain the vacuum state, open the air intake proportional valve, let the dry gas enter the vacuum chamber through the air intake proportional valve, and adjust the opening of the air intake proportional valve so that the air flow inside the vacuum chamber is at a vacuum degree of (1-x)A n to (1+x)A n Keep flowing within the range of t n Then close the intake proportional valve, where a n Represents the value of the nth decrease in the rate of change of vacuum degree;

[0011] S5. Repeat S4 several times until the vacuum degree drops to V min And maintain time t min Finally, turn off the vacuum to complete the water removal.

[0012] By adopting the above technical solution, the battery is fully heated during operation, so that the water inside the battery can be continuously evaporated, preparing for the subsequent vacuum pumping process. During the vacuum pumping process, the vacuum degree inside the vacuum cavity is monitored in real time by the detection device, and the water removal condition inside the vacuum cavity can be detected. By monitoring the rate of change of the vacuum degree, the speed and state of water evaporation can be judged. When the rate of change of the vacuum degree decreases to a certain extent, it indicates that the water evaporation rate of the battery has slowed down. At this time, the dry gas is introduced by opening the air intake proportional valve, and the opening of the air intake proportional valve is adjusted to ensure that the air flow inside the vacuum cavity is maintained within a certain range of vacuum degree. That is, in the vacuum cavity, the vacuum pumping process, the battery water evaporation process and the remaining dry gas flow process are all performed simultaneously. A dynamic balance is achieved between the processes, so that the flowing dry gas can continuously take away the residual moisture on the surface and inside of the battery, and by repeating this step several times and gradually reducing the vacuum degree change rate required before opening the intake proportional valve each time, so as to adapt to the working conditions where the vacuum degree inside the vacuum chamber is lower and the vacuum pumping process is slower, the vacuum degree in the vacuum chamber can be reduced in stages, and the moisture inside the battery can be removed in a timely and continuous manner while reducing energy consumption. Compared with the traditional vacuum pumping and dehydration method, the residual moisture in the battery before pressure relief can be further reduced, thereby avoiding the situation where a large amount of water molecules return to the battery during pressure relief during baking and need to be re-vacuumed, thereby shortening the overall drying time of the battery, improving the battery dehydration efficiency, and improving product quality.

[0013] In a preferred example, the present application can be further configured as follows: the detection device includes a pressure gauge and a PLC control system, the pressure gauge is arranged in the vacuum chamber and is used to monitor the vacuum degree inside the vacuum chamber in real time, the PLC control system is used to set a program to calculate the rate of change of the vacuum degree in real time, and the PLC control system is controlled and connected to the vacuum pump, the pressure gauge and the intake proportional valve.

[0014] By adopting the above technical solution, during the vacuuming process, the pressure gauge monitors the vacuum degree inside the vacuum chamber in real time and transmits the data to the PLC control system. The PLC control system calculates the rate of change of the vacuum degree in real time based on the received pressure data using a preset program algorithm. When the rate of change of the vacuum degree decreases to a certain extent, the PLC control system triggers a preset supplementary program. At this time, the PLC control system controls the opening of the intake proportional valve to allow dry gas to enter the vacuum chamber through the intake valve. At the same time, the PLC control system adjusts the opening of the intake valve to keep the air flow inside the vacuum chamber flowing within the range of vacuum degree A±x.

[0015] In a preferred example, the present application can be further configured as follows: the value range of V1 is 0-10 Pa / s.

[0016] In a preferred example, the present application can be further configured as follows: the value range of x is 5%-20%.

[0017] By adopting the above technical solution, x adopts this numerical range to achieve a dynamic balance among the vacuum extraction process, the battery water evaporation process and the remaining dry gas flow process in the vacuum cavity, so that the flowing dry gas can continuously carry away the residual moisture on the surface and inside of the battery.

[0018] In a preferred example, the present application can be further configured as follows: t1, t n and t min The value range is 1-10min.

[0019] In a preferred example, the present application can be further configured as: V min The value range is 10-50pa.

[0020] In a preferred example, the present application may be further configured as follows: during the vacuuming process, the interior of the vacuum chamber is heated continuously or intermittently.

[0021] By adopting the above technical solution, the battery can be heated during the vacuuming process to avoid the situation where the drying efficiency is reduced due to the reduction of battery temperature after the moisture on the surface and inside of the battery is converted into steam.

[0022] In summary, the present application includes at least one of the following beneficial technical effects:

[0023] 1. During the vacuuming process, the vacuum degree inside the vacuum cavity is monitored in real time by the detection device, and the dehydration situation inside the vacuum cavity can be detected. By monitoring the change rate of the vacuum degree, the speed and state of water evaporation can be judged. When the change rate of the vacuum degree decreases to a certain degree, it means that the water evaporation rate of the battery has slowed down. At this time, by opening the air intake proportional valve, dry gas is introduced, and by adjusting the opening of the air intake proportional valve, it is ensured that the air flow inside the vacuum cavity is maintained under a certain range of vacuum degree. That is, in the vacuum cavity, a dynamic balance is achieved between the vacuuming process, the battery water evaporation process and the remaining dry gas flow process, so that the flowing dry gas can continuously take away the residual water on the surface and inside of the battery, and by repeating this step several times and gradually reducing the vacuum degree change rate required before opening the air intake proportional valve each time, so as to adapt to the lower the vacuum degree inside the vacuum cavity and the slower the vacuuming process, the vacuum degree in the vacuum cavity can be reduced in stages, and the water inside the battery can be removed in a timely and continuous manner while reducing energy consumption.

[0024] 2. Compared with the traditional vacuum dehydration method, it can further reduce the residual moisture in the battery before decompression, thereby avoiding the situation where a large amount of water molecules return to the battery during decompression during baking and need to be re-vacuumed, thereby shortening the overall drying time of the battery, improving the battery dehydration efficiency, and improving product quality.

[0025] 3. During the vacuuming process, the pressure gauge monitors the vacuum degree inside the vacuum chamber in real time and transmits the data to the PLC control system. The PLC control system calculates the rate of change of the vacuum degree in real time based on the received pressure data using a preset program algorithm. When the rate of change of the vacuum degree decreases to a certain extent, the PLC control system triggers the preset supplementary program. At this time, the PLC control system controls the opening of the intake proportional valve to allow the dry gas to enter the vacuum chamber through the intake valve. At the same time, the PLC control system adjusts the opening of the intake valve to keep the air flow inside the vacuum chamber flowing within the range of vacuum degree A±x. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of a flow chart of a battery staged flow vacuum dehydration method of the present application;

[0027] Figure 2 It is a schematic diagram of the system structure of a battery staged flow vacuum dehydration method of the present application. DETAILED DESCRIPTION

[0028] The following is a description of exemplary embodiments of the present application in conjunction with the accompanying drawings, including various details of the embodiments of the present application to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. Similarly, for the sake of clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0029] It should be noted that the terms "first", "second", etc. in the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure.

[0030] In addition, the term "and / or" in this article 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 article, unless otherwise specified, generally means that the associated objects before and after are in an "or" relationship.

[0031] A battery staged flow vacuum dehydration method of the present application is described below with reference to the accompanying drawings.

[0032] like Figure 1 and Figure 2 As shown, a battery staged flow vacuum dehydration method comprises the following steps:

[0033] S1, placing the battery into the vacuum chamber, and heating the battery until the battery reaches a set temperature value or a set time;

[0034] The vacuum chamber may be any closed environment capable of achieving high vacuum, such as a vacuum oven, a drying oven, or other equipment capable of providing an installation location and heating function for the battery. The above-mentioned set temperature value and set time shall be determined according to the model characteristics of the battery and are not limited here;

[0035] S2, evacuating the inside of the vacuum chamber by a vacuum pump, and in the process of evacuating the inside of the vacuum chamber, monitoring the vacuum degree of the inside of the vacuum chamber in real time by a detection device and calculating the rate of change of the vacuum degree in real time;

[0036] S3. Set a supplementary program. When the rate of change of the vacuum degree is less than or equal to V1, record the vacuum degree at this time as A1, maintain the vacuum state, open the air intake proportional valve, allow the dry gas to enter the vacuum chamber through the air intake proportional valve, and adjust the opening of the air intake proportional valve so that the air flow inside the vacuum chamber is maintained within the range of vacuum degree (1-x)A1 to (1+x)A1. After maintaining the time t1, close the air intake proportional valve;

[0037] S4, when the rate of change of vacuum degree is less than (V1-a n ), record the vacuum degree as A n , maintain the vacuum state, open the air intake proportional valve, let the dry gas enter the vacuum chamber through the air intake proportional valve, and adjust the opening of the air intake proportional valve so that the air flow inside the vacuum chamber is at a vacuum degree of (1-x)A n to (1+x)A n Keep flowing within the range of t n Then close the intake proportional valve, where a n Represents the value of the nth decrease in the rate of change of vacuum degree;

[0038] In S3 and S4, the value range of x is 5%-20%. x adopts this value range to achieve a dynamic balance between the vacuuming process, the battery water evaporation process and the remaining dry gas flow process in the vacuum chamber, so that the flowing dry gas can continuously remove the residual moisture on the surface and inside of the battery. In S3 and S4, t1, t n The value range is 1-10min.

[0039] S5. Repeat S4 several times until the vacuum degree drops to V min And maintain time t min Finally, turn off the vacuum to complete the water removal.

[0040] Among them, in S5, V min The value range is 10-50pa, t min The value range is 1-10min.

[0041] It should be noted that in S4, A n Represents the vacuum degree of the vacuum chamber when the vacuum degree change rate is less than the set value for the nth time, a n Represents the value of the nth vacuum degree change rate reduction, a n It needs to be determined comprehensively based on factors such as the battery system, the performance of the vacuum pump, and the size of the vacuum chamber. After repeating S4 several times, the rate of change of vacuum degree gradually approaches 0. In S5, the number of times S4 is repeated is approximately 2-100 times, depending on factors such as the battery system, the performance of the vacuum pump, and the size of the vacuum chamber.

[0042] In addition, in S2, the detection device includes a pressure gauge and a PLC control system. The pressure gauge is arranged in the vacuum cavity and is used to monitor the vacuum degree inside the vacuum cavity in real time. The PLC control system is used to set a program to calculate the rate of change of the vacuum degree in real time. The PLC control system is connected to the vacuum pump, the pressure gauge and the intake proportional valve. During the vacuum pumping process, the pressure gauge monitors the vacuum degree inside the vacuum cavity in real time and transmits the data to the PLC control system. The PLC control system calculates the rate of change of the vacuum degree in real time based on the received pressure data using a preset program algorithm. When the rate of change of the vacuum degree decreases to a certain extent, the PLC control system triggers a preset supplementary program. At this time, the PLC control system controls the intake proportional valve to open, so that the dry gas enters the vacuum cavity through the intake valve. At the same time, the PLC control system adjusts the opening of the intake valve so that the airflow inside the vacuum cavity remains flowing within the range of the vacuum degree A±x.

[0043] During the working process, the battery is fully heated to enable the water inside the battery to evaporate continuously, preparing for the subsequent vacuum pumping process. During the vacuum pumping process, the vacuum degree inside the vacuum chamber is monitored in real time by the detection device, and the water removal inside the vacuum chamber can be detected. By monitoring the rate of change of the vacuum degree, the speed and state of water evaporation can be judged. When the rate of change of the vacuum degree decreases to a certain extent, it means that the water evaporation rate of the battery has slowed down. At this time, the dry gas is introduced by opening the air intake proportional valve, and the opening of the air intake proportional valve is adjusted to ensure that the air flow inside the vacuum chamber is maintained within a certain range of vacuum degree. That is, in the vacuum chamber, the vacuum pumping process, the battery water evaporation process and the remaining dry gas flow process are synchronized. Dynamic balance is achieved during the drying process, so that the flowing dry gas can continuously take away the residual moisture on the surface and inside of the battery, and by repeating this step several times and gradually reducing the vacuum change rate required before opening the intake proportional valve each time, so as to adapt to the working conditions where the vacuum degree inside the vacuum chamber is lower and the vacuum pumping process is slower, the vacuum degree in the vacuum chamber can be reduced in stages, and the moisture inside the battery can be removed in a timely and continuous manner while reducing energy consumption. Compared with the traditional vacuum pumping and dehydration method, the residual moisture in the battery before pressure relief can be further reduced, thereby avoiding the situation where a large amount of water molecules return to the battery during the pressure relief process and need to be re-vacuumed, thereby shortening the overall drying time of the battery, improving the battery dehydration efficiency, and improving product quality.

[0044] Furthermore, during the vacuuming process, the interior of the vacuum cavity is heated continuously or intermittently, so that the battery can be heated during the vacuuming process to avoid the situation where the drying efficiency is reduced due to the reduction of battery temperature after the moisture on the surface and inside of the battery is converted into steam, wherein the heating method may include but is not limited to liquid bath heating, electric heating and the like.

[0045]

[0046] Table 1

[0047] In one embodiment, Table 1 shows two experimental groups, with a volume of 5.5m 3 An experimental data table is provided in which 2835 cylindrical 40135-20AH lithium iron phosphate system batteries are placed in a vacuum oven and then dehydrated and dried using the conventional process and the process of the present invention. It can be concluded from Table 1 that the dehydration and drying method of the present invention has significantly shortened the process time compared with the conventional process, greatly saved the consumption of drying gas, and also significantly reduced the energy consumption.

[0048] The above specific implementations do not constitute a limitation on the protection scope of this application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this application should be included in the protection scope of this application.

Claims

1. A battery staged flow vacuum dehydration method, characterized in that: The following steps are involved: S1, placing the battery into the vacuum chamber, and heating the battery until the battery reaches a set temperature value or a set time; S2, evacuating the inside of the vacuum chamber by a vacuum pump, and in the process of evacuating the inside of the vacuum chamber, monitoring the vacuum degree of the inside of the vacuum chamber in real time by a detection device and calculating the rate of change of the vacuum degree in real time; S3. Set a supplementary program. When the rate of change of the vacuum degree is less than or equal to V1, record the vacuum degree at this time as A1, maintain the vacuum state, open the air intake proportional valve, allow the dry gas to enter the vacuum chamber through the air intake proportional valve, and adjust the opening of the air intake proportional valve so that the air flow inside the vacuum chamber is maintained within the range of vacuum degree (1-x)A1 to (1+x)A1. After maintaining the time t1, close the air intake proportional valve; S4, when the rate of change of vacuum degree is less than (V1-a n ), record the vacuum degree as A n , maintain the vacuum state, open the air intake proportional valve, let the dry gas enter the vacuum chamber through the air intake proportional valve, and adjust the opening of the air intake proportional valve so that the air flow inside the vacuum chamber is at a vacuum degree of (1-x)A n to (1+x)A n Keep flowing within the range of t n Then close the intake proportional valve, where a n Represents the value of the nth decrease in the rate of change of vacuum degree; S5. Repeat S4 several times until the vacuum degree drops to V min And maintain time t min Finally, turn off the vacuum to complete the water removal.

2. A battery staged flow vacuum dehydration method as claimed in claim 1, characterized in that: The detection device includes a pressure gauge and a PLC control system. The pressure gauge is arranged in the vacuum chamber and is used to monitor the vacuum degree inside the vacuum chamber in real time. The PLC control system is used to set a program to calculate the rate of change of the vacuum degree in real time. The PLC control system is controlled and connected to the vacuum pump, the pressure gauge and the intake proportional valve.

3. A battery staged flow vacuum dehydration method as claimed in claim 1, characterized in that: The value range of V1 is 0-10pa / s.

4. A battery staged flow vacuum dehydration method as claimed in claim 1, characterized in that: The value range of x is 5%-20%.

5. A battery staged flow vacuum dehydration method as claimed in claim 1, characterized in that: t1, t n and t min The value range is 1-10min.

6. A battery staged flow vacuum dehydration method as claimed in claim 1, characterized in that: V min The value range is 10-50pa.

7. A battery staged flow vacuum dehydration method as claimed in claim 1, characterized in that: During the vacuuming process, the interior of the vacuum cavity is heated continuously or intermittently.

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