A method for removing water from a battery by fractional flow vacuuming

Abstract

The present application relates to the technical field of electric battery drying, in particular to a battery staged flow type vacuum drying method, compared with the traditional vacuum drying method, the present application can avoid the situation that a large number of water molecules return to the battery during pressure relief in the baking process, and then the overall drying time of the battery is shortened, the drying efficiency of the battery is improved, the amount of drying gas is reduced, and the product quality is improved.

Description

A staged flow-type vacuum dehydration method for batteries Technical Field

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

[0002] In the production process of lithium batteries, the dehydration and drying process is a critical step that affects the quality of lithium batteries. If the lithium battery is not dried sufficiently, the electrolyte inside the battery will react with water to generate trace amounts of harmful gases, which will have an adverse effect on the environment of the electrolyte filling room. At the same time, it will also affect the quality of the electrolyte itself, resulting in poor battery performance and causing the battery rivets to rust. Therefore, it is necessary to dehydrate and dry the lithium battery to avoid the impact of moisture on the lithium battery and the electrolyte filling environment.

[0003] In existing technologies, the traditional method of battery dehydration and drying involves placing the battery in a vacuum chamber and heating it using convection heating, and then removing the moisture inside the vacuum chamber by evacuation. However, when depressurization is applied during the heating process, water molecules that were about to precipitate from the battery under the original high vacuum state return to the cell, which can easily lead to insufficient drying of the battery. This necessitates repeated evacuation processes, thus prolonging the overall drying time of the battery and making it difficult to achieve the ideal battery dehydration and drying efficiency. This issue urgently needs to be addressed. Summary of the Invention

[0004] To address the shortcomings of the prior art, this application provides a staged flow-type vacuum dehydration method for batteries.

[0005] The above-mentioned inventive objective of this application is achieved through the following technical solutions:

[0006] A staged flow-type vacuum dehydration method for batteries includes the following steps:

[0007] S1. Place the battery inside the vacuum chamber and heat the battery until it reaches the set temperature or set time.

[0008] S2. The vacuum chamber is evacuated by a vacuum pump. During the evacuation process, the vacuum level inside the vacuum chamber is monitored in real time by a detection device, and the rate of change of the vacuum level is calculated in real time.

[0009] S3. Set up a supplementary program. When the rate of change of vacuum degree is less than or equal to V1, record the vacuum degree at this time as A1, maintain the vacuum state, open the intake proportional valve, and let the dry gas enter the vacuum chamber through the intake proportional valve. By adjusting the opening of the intake proportional valve, the airflow inside the vacuum chamber is kept flowing within the range of vacuum degree (1-x)A1 to (1+x)A1. After maintaining for a time t1, close the intake proportional valve.

[0010] S4. When the rate of change of vacuum degree is less than (V1 - a) n When the vacuum level is recorded as A, record the vacuum level at that time. n Maintain the vacuum state, open the intake proportional valve to allow dry gas to enter the vacuum chamber through the intake proportional valve, and adjust the opening of the intake proportional valve to ensure that the airflow inside the vacuum chamber is within a vacuum of (1-x)A. n To (1+x)A n Maintain flow within a certain range, for a duration of t. n Then close the intake proportional valve, where a n This represents the decrease in the rate of change of vacuum degree for the nth time;

[0011] S5. Repeat S4 several times until the vacuum level drops to V. min And maintain for time t min Then, turn off the vacuum pump to complete the water removal process.

[0012] By adopting the above technical solution, the battery is fully heated during operation, allowing for continuous evaporation of internal moisture, preparing for the subsequent vacuuming process. During vacuuming, the vacuum level inside the vacuum chamber is monitored in real time by a detection device, enabling the detection of water removal within the chamber. Furthermore, by monitoring the rate of change in vacuum level, the speed and state of moisture evaporation can be determined. When the rate of change in vacuum level decreases to a certain extent, it indicates that the battery's moisture evaporation rate has slowed down. At this point, dry gas is introduced by opening the intake proportional valve, and the opening of the intake proportional valve is adjusted to ensure airflow within the vacuum chamber under a certain vacuum level. In other words, within the vacuum chamber, the vacuuming process, the battery water evaporation process, and the flow of other dry gas are all integrated. A dynamic balance is achieved between the processes, allowing the flowing dry gas to continuously remove residual moisture from the battery surface and interior. By repeating this step several times and gradually reducing the rate of change in vacuum required before each opening of the intake proportional valve, the vacuuming process can be adapted to the condition that the lower the vacuum level inside the vacuum chamber, the slower the vacuuming process. This allows for a phased reduction of the vacuum level inside the vacuum chamber, reducing energy consumption while continuously and promptly removing moisture from the battery. Compared to traditional vacuum dehydration methods, this method further reduces the moisture remaining in the battery before depressurization, thus avoiding the situation where a large number of water molecules return to the battery during the depressurization process in the baking process, requiring re-vacuuming. This shortens the overall drying time of the battery, improves the battery dehydration efficiency, and enhances product quality.

[0013] In a preferred embodiment, the present application may be further configured such that: the detection device includes a pressure gauge and a PLC control system, the pressure gauge is disposed in the vacuum chamber and is used to monitor the vacuum level inside the vacuum chamber in real time, the PLC control system is used to set a program to calculate the rate of change of vacuum level in real time, and the PLC control system is 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 level inside the vacuum chamber in real time and transmits the data to the PLC control system. Based on the received pressure data, the PLC control system calculates the rate of change of vacuum level in real time using a preset program algorithm. When the rate of change of vacuum level 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, allowing dry gas to enter the vacuum chamber through the intake valve. Simultaneously, the PLC control system adjusts the opening of the intake valve to ensure that the airflow inside the vacuum chamber remains within the vacuum level range of A±x.

[0015] In a preferred example, this application can be further configured such that the value of V1 ranges from 0 to 10 Pa / s.

[0016] In a preferred example, this application can be further configured such that the value of x ranges from 5% to 20%.

[0017] By adopting the above technical solution, x adopts this numerical range so that a dynamic balance is achieved between the vacuuming process, the battery water evaporation process and the other dry gas flow process in the vacuum chamber, so that the flowing dry gas can continuously remove the residual moisture on the battery surface and inside.

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

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

[0020] In a preferred embodiment, this application may be further configured to continuously or intermittently heat the interior of the vacuum chamber during the vacuuming process.

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

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

[0023] 1. During the vacuuming process, the vacuum level inside the vacuum chamber is monitored in real time by a detection device. This allows for the detection of water removal within the vacuum chamber and the assessment of the rate of change in vacuum level to determine the speed and state of water evaporation. When the rate of change in vacuum level decreases to a certain extent, it indicates that the rate of water evaporation from the battery has slowed down. At this point, the intake proportional valve is opened to introduce dry gas. By adjusting the opening of the intake proportional valve, the airflow inside the vacuum chamber is maintained within a certain vacuum level. This achieves a dynamic balance between the vacuuming process, the battery water evaporation process, and the flow of other dry gas within the vacuum chamber. This ensures that the flowing dry gas can continuously remove residual moisture from the battery surface and interior. By repeating this step several times and gradually reducing the rate of change in vacuum level required before each opening of the intake proportional valve, the vacuuming process can be adapted to the condition that the lower the vacuum level inside the vacuum chamber, the slower the vacuuming process. This allows for a phased reduction of the vacuum level inside the vacuum chamber, reducing energy consumption while continuously and promptly removing moisture from inside the battery.

[0024] 2. Compared with the traditional vacuum dehydration method, it can further reduce the moisture remaining in the battery before depressurization, thereby avoiding the situation where a large number of water molecules return to the battery during the depressurization process and need to be vacuumed again. This shortens the overall drying time of the battery, improves the battery dehydration efficiency, and improves product quality.

[0025] 3. During the vacuuming process, the pressure gauge monitors the vacuum level inside the vacuum chamber in real time and transmits the data to the PLC control system. Based on the received pressure data, the PLC control system uses a preset algorithm to calculate the rate of change of vacuum level in real time. When the rate of change of vacuum level 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, allowing dry gas to enter the vacuum chamber through the intake valve. Simultaneously, the PLC control system adjusts the opening of the intake valve to ensure that the airflow inside the vacuum chamber remains within the vacuum level range of A±x. Attached Figure Description

[0026] Figure 1 is a schematic flowchart of a staged flow-type vacuum dehydration method for batteries according to this application.

[0027] Figure 2 is a schematic diagram of the system configuration of a staged flow-type vacuum dehydration method for batteries according to this application. Detailed Implementation

[0028] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of this application, including various details to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

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

[0030] Furthermore, the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article, unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship.

[0031] The following description, with reference to the accompanying drawings, illustrates a staged flow-type vacuum dehydration method for batteries according to this application.

[0032] As shown in Figures 1 and 2, a staged flow-type vacuum dehydration method for batteries includes the following steps:

[0033] S1. Place the battery inside the vacuum chamber and heat the battery until it reaches the set temperature or set time.

[0034] The vacuum chamber can be any enclosed environment capable of achieving high vacuum, such as a vacuum oven or drying oven, which can provide an installation location and heating function for the battery. The above-mentioned set temperature and set time need to be determined according to the characteristics of the battery model, and there are no restrictions here.

[0035] S2. The vacuum chamber is evacuated by a vacuum pump. During the evacuation process, the vacuum level inside the vacuum chamber is monitored in real time by a detection device, and the rate of change of the vacuum level is calculated in real time.

[0036] S3. Set up a supplementary program. When the rate of change of vacuum degree is less than or equal to V1, record the vacuum degree at this time as A1, maintain the vacuum state, open the intake proportional valve, and let the dry gas enter the vacuum chamber through the intake proportional valve. By adjusting the opening of the intake proportional valve, the airflow inside the vacuum chamber is kept flowing within the range of vacuum degree (1-x)A1 to (1+x)A1. After maintaining for a time t1, close the intake proportional valve.

[0037] S4. When the rate of change of vacuum degree is less than (V1 - a) n When the vacuum level is recorded as A, record the vacuum level at that time. n Maintain the vacuum state, open the intake proportional valve to allow dry gas to enter the vacuum chamber through the intake proportional valve, and adjust the opening of the intake proportional valve to ensure that the airflow inside the vacuum chamber is within a vacuum of (1-x)A. n To (1+x)A n Maintain flow within a certain range, for a duration of t. n Then close the intake proportional valve, where a n This represents the decrease in the rate of change of vacuum degree for the nth time;

[0038] In S3 and S4, the value of x ranges from 5% to 20%. This range is used to achieve a dynamic balance between the vacuuming process, the battery water evaporation process, and the remaining dry gas flow process within the vacuum chamber. This ensures that the flowing dry gas can continuously remove residual moisture from the battery surface and interior. In S3 and S4, t1 and t n The value range is 1-10 min.

[0039] S5. Repeat S4 several times until the vacuum level drops to V.min And maintain for time t min Then, turn off the vacuum pump to complete the water removal process.

[0040] In S5, V min The value range is 10-50 Pa, t min The value range is 1-10 min.

[0041] It should be noted that in S4, A n a represents the vacuum level of the vacuum chamber when the rate of change of vacuum level is less than the set value for the nth time. n a represents the decrease in the rate of change of vacuum degree for the nth time. n The vacuum level 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 level gradually approaches 0. In S5, depending on factors such as the battery system, the performance of the vacuum pump, and the size of the vacuum chamber, the number of times S4 is repeated is approximately 2-100 times.

[0042] In addition, in S2, the detection device includes a pressure gauge and a PLC control system. The pressure gauge is installed in the vacuum chamber and is used to monitor the vacuum level inside the vacuum chamber in real time. The PLC control system is used to set a program to calculate the rate of change of vacuum level in real time. The PLC control system controls the connection to the vacuum pump, pressure gauge and inlet proportional valve. During the vacuuming process, the pressure gauge monitors the vacuum level 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 vacuum level in real time based on the received pressure data using a preset program algorithm. When the rate of change of vacuum level decreases to a certain extent, the PLC control system triggers a preset supplementary program. At this time, the PLC control system controls the inlet proportional valve to open, allowing dry gas to enter the vacuum chamber through the inlet valve. At the same time, the PLC control system adjusts the opening of the inlet valve to keep the airflow inside the vacuum chamber flowing within the vacuum level range of A±x.

[0043] During operation, the battery is fully heated, allowing internal moisture to evaporate continuously, preparing for the subsequent vacuuming process. During vacuuming, a detection device monitors the vacuum level inside the vacuum chamber in real time, detecting the water removal process and assessing the rate of change in vacuum level to determine the speed and state of moisture evaporation. When the rate of change in vacuum level decreases to a certain extent, it indicates that the battery's moisture evaporation rate has slowed down. At this point, the intake proportional valve is opened to introduce dry gas, and the valve's opening is adjusted to maintain airflow within the vacuum chamber at a certain vacuum level. This process integrates the vacuuming process, the battery water evaporation process, and the flow of other dry gas processes within the vacuum chamber. A dynamic equilibrium is achieved, allowing the flowing dry gas to continuously remove residual moisture from the battery surface and interior. By repeating this step several times and gradually reducing the rate of vacuum change required before each opening of the intake proportional valve, the vacuum level inside the vacuum chamber decreases as the vacuum level decreases and the vacuuming process becomes slower. This allows for a phased reduction of the vacuum level inside the vacuum chamber, reducing energy consumption while continuously and promptly removing moisture from the battery. Compared to traditional vacuum dehydration methods, this further reduces the moisture remaining in the battery before depressurization, thus avoiding the need for re-vacuuming after a large number of water molecules return to the battery during depressurization. This shortens the overall drying time of the battery, improves battery dehydration efficiency, and enhances product quality.

[0044] Furthermore, during the vacuuming process, the inside of the vacuum chamber is continuously or intermittently heated. This allows the battery to be heated during the vacuuming process, thus avoiding a decrease in drying efficiency due to the battery temperature dropping after the surface and internal moisture are converted into vapor. The heating method can include, but is not limited to, liquid bath heating, electric heating, etc.

[0045]

[0046] Table 1

[0047] In one embodiment, Table 1 shows the two experimental groups used in a volume of 5.5 m³. 3 The experimental data table shows that 2835 cylindrical 40135-20AH lithium iron phosphate batteries were placed in a vacuum oven and dried using both traditional and the process of this invention. As can be seen from Table 1, the dehydration and drying method of this invention significantly shortens the process time, greatly saves the consumption of drying gas, and also significantly reduces energy consumption compared with the traditional process.

[0048] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand 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 within the scope of protection of this application.

Claims

1. A staged flow-type vacuum dehydration method for batteries, characterized in that, Includes the following steps: S1. Place the battery inside the vacuum chamber and heat it until it reaches the set temperature or a set time. S2. Evacuate the vacuum chamber using a vacuum pump. During evacuation, monitor the vacuum level inside the chamber and calculate the rate of change of vacuum level in real time using a detection device. S3. Set a supplementary program. When the rate of change of vacuum level is less than or equal to V1, record the vacuum level as A1. Maintain the evacuation state, open the intake proportional valve to allow dry gas to enter the vacuum chamber through the valve, and adjust the opening of the intake proportional valve to keep the airflow inside the vacuum chamber within a vacuum level range of (1-x)A1 to (1+x)A1. Maintain this for time t1, then close the intake proportional valve. S4. When the rate of change of vacuum level is less than (V1-a... n When the vacuum level is recorded as A, record the vacuum level at that time. n Maintain the vacuum state, open the intake proportional valve to allow dry gas to enter the vacuum chamber through the intake proportional valve, and adjust the opening of the intake proportional valve to ensure that the airflow inside the vacuum chamber is within a vacuum of (1-x)A. n To (1+x)A n Maintain flow within a certain range, for a duration of t. n Then close the intake proportional valve, where a n This represents the value representing the decrease in the rate of change of vacuum degree for the nth time; S5, repeat S4 several times until the vacuum degree decreases to V. min And maintain for time t min Then, turn off the vacuum pump to complete the water removal process.

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

3. The battery staged flow-type vacuum dehydration method as described in claim 1, characterized in that, The value of V1 ranges from 0 to 10 Pa / s.

4. The battery staged flow-type vacuum dehydration method as described in claim 1, characterized in that, The value of x ranges from 5% to 20%.

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

6. The battery staged flow-type vacuum dehydration method as described in claim 1, characterized in that, V min The value range is 10-50 Pa.

7. The battery staged flow-type vacuum dehydration method as described in claim 1, characterized in that, During the vacuuming process, the inside of the vacuum chamber is continuously heated or intermittently heated.

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