A kind of air extraction device and battery formation system

Abstract

The application relates to the technical field of battery manufacturing, in particular to an air extraction device and a battery formation system. The air extraction device comprises a buffer cup and a turbulence mechanism. The buffer cup has an air inlet and an air outlet. The air inlet is used for being in communication with the inside of a battery monomer, so that the gas in the battery monomer flows to the buffer cup. The air outlet is used for being connected with a vacuum extraction device, so that the gas in the buffer cup flows out. The turbulence mechanism has an air outlet end which is located in the buffer cup and is used for blowing the gas in the buffer cup, so as to increase the probability of the gas in the buffer cup contacting the cup wall of the buffer cup, and make the electrolyte vapor condense on the surface of the cup wall. The air extraction device and the formation system provided by the application can make the electrolyte vapor extracted in the formation process condense and flow back to the battery monomer, and reduce the loss of the electrolyte.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery manufacturing, and in particular to an air extraction device and a battery formation system. BACKGROUND

[0002] Formation is an important process in the manufacturing process of lithium ion batteries, and its main purpose is to form a solid electrolyte interphase (SEI) on the surface of the electrode material during the first charging process. The performance of the SEI will directly determine the cycle performance of the battery and the consistency of the battery.

[0003] During the formation process, the battery monomer needs to be heated, and the gas in the battery monomer needs to be extracted to make the inside of the battery monomer in a negative pressure state. After the existing air extraction device extracts the gas in the battery monomer, a large amount of electrolyte is often lost, which causes the battery formation interface to be poor and directly affects the service life of the battery.

[0004] Therefore, how to reduce the loss of electrolyte during the formation process is a problem that needs to be solved. SUMMARY

[0005] In view of the above problems, the embodiments of the present application provide an air extraction device and a formation system, which can make the electrolyte vapor extracted during the formation process condense and flow back to the battery monomer, thereby reducing the loss of electrolyte.

[0006] According to an aspect of an embodiment of the present application, an air extraction device is provided, which comprises:

[0007] The buffer cup has a gas inlet and a gas outlet. The gas inlet is used to communicate with the inside of the battery monomer, so that the gas in the battery monomer flows to the buffer cup. The gas outlet is used to connect the vacuum extraction device, so that the gas in the buffer cup flows out.

[0008] The turbulence mechanism has an air outlet end located in the buffer cup, which is used to blow the gas in the buffer cup to increase the probability of contact between the gas in the buffer cup and the cup wall of the buffer cup, so that the electrolyte vapor condenses on the surface of the cup wall.

[0009] By adopting the above scheme, the vacuum device allows the high-temperature gas inside the battery cell to enter the buffer cup from the air inlet and then flow out from the air outlet. During the process of the gas flowing through the buffer cup, it is turbulent by the turbulence mechanism inside the buffer cup, changing its original flow direction. The gas travels a longer path and stays in the buffer cup for a longer time, thereby increasing the probability of the gas contacting the cup wall. When the gas contacts the cup wall, the electrolyte vapor condenses due to the temperature difference between the gas and the buffer cup. The condensate flows and collects along the cup wall. When the condensate reaches the air inlet, it flows back into the battery cell to replenish the electrolyte and reduce electrolyte loss.

[0010] In some embodiments, the orientation of the air outlet is set at an angle to the first direction, the angle being greater than 0° and less than 360°; the first direction is a straight line from the air inlet to the air outlet.

[0011] By adopting the above scheme, without the turbulence mechanism, the gas flows from the inlet to the outlet in the buffer cup via the shortest path, during which the probability of contact between the gas and the cup wall is relatively small. With the turbulence mechanism installed, the gas in the buffer cup is agitated, changing its original flow direction. This lengthens the gas's path within the buffer cup and makes it easier for the gas to contact the cup wall, accelerating the condensation of electrolyte vapor.

[0012] In some embodiments, the air inlet and air outlet are arranged opposite to each other, and the turbulence mechanism is located on the side where the air outlet is located.

[0013] By adopting the above scheme, as the gas flows from the inlet to the outlet, the resistance from the turbulence mechanism gradually increases, thereby gradually slowing down the gas flow speed, or changing the original flow path and flowing in a more tortuous path. During this process, the probability of contact with the wall of the buffer cup is further increased, which causes more electrolyte vapor in the gas to condense on the wall of the buffer cup, reducing the amount of electrolyte vapor mixed in the gas flowing out of the outlet and reducing electrolyte loss.

[0014] In some embodiments, the turbulence mechanism includes a fan disposed within a buffer cup.

[0015] By adopting the above scheme, the airflow direction of the fan is more dispersed, the area of ​​influence on the gas in the buffer cup is also larger, and the wind speed of the fan at the same position is constantly changing, which has a better turbulence effect on the gas in the buffer cup, and further helps to accelerate the condensation of electrolyte vapor in the buffer cup.

[0016] In some embodiments, the fan is at least partially located on the line connecting the air inlet and the air outlet.

[0017] By adopting the above scheme, during the process of gas flowing from the inlet to the outlet, at least a portion of the gas is directly obstructed by the fan and cannot flow out in a straight direction, thereby changing the gas flow path. In the process of changing the path, the probability of electrolyte vapor contacting the cup wall of the buffer cup is increased.

[0018] In some embodiments, along the first direction, the projection of the fan on the cup wall where the air outlet is located completely covers the projection of the air inlet on the cup wall where the air outlet is located.

[0019] By adopting the above scheme, after the gas enters the buffer cup from the air inlet, it is immediately subjected to the resistance of the fan, which further increases the path length of the gas flow in the buffer cup and increases the probability of the gas condensing in the buffer cup.

[0020] In some embodiments, the turbulence mechanism further includes a connector located between the fan and the wall of the buffer cup for connecting the fan to the wall of the buffer cup.

[0021] By adopting the above solution, since the fan is connected to the wall of the buffer cup through a connector, the fan's position is not limited by factors such as the shape and structure of the buffer cup. Instead, it is only necessary to consider whether it has a better turbulence effect, thus making the fan's position more flexible.

[0022] In some embodiments, the turbulence mechanism further includes a wire, one end of which is connected to the motor of the fan, and the other end of which extends through the wall of the buffer cup for electrical connection to an external power source; the connector has a lead cavity, and the portion of the wire located inside the buffer cup is located inside the lead cavity to prevent gas from corroding the wire.

[0023] By adopting the above solution, the fan can be turned on or off by an external power source, making the operation of the turbulence mechanism more convenient. In addition, by placing the wires inside the lead wire cavity, the wires are less susceptible to corrosion and damage, resulting in a lower failure rate and a longer service life for the air extraction device.

[0024] In some embodiments, the turbulence mechanism includes a turbulence tube, with the air outlet of the turbulence tube located inside the buffer cup and the air inlet located outside the buffer cup, for connecting to an air blowing device.

[0025] By adopting the above scheme, the air blowing device blows air into the buffer cup through the turbulence pipe, thereby disturbing the gas in the buffer cup and increasing the probability that the gas in the buffer cup will contact the buffer cup and condense on the cup wall.

[0026] In some embodiments, the buffer cup has a condensation cavity in its wall for containing a condensing medium.

[0027] By adopting the above scheme, the temperature of the buffer cup is further reduced, the temperature difference between the cup wall and the gas inside the buffer cup is increased, and the condensation of electrolyte vapor is accelerated.

[0028] In some embodiments, the buffer cup is a hollow cone or pyramid, and the air inlet is located at the tip of the cone or pyramid to allow condensate to flow out from the air inlet.

[0029] By adopting the above scheme, when the air inlet of the buffer cup is inserted into the battery cell with the air inlet facing downwards, the condensate in the buffer cup collects on the cup wall and eventually flows into the battery cell from the air inlet. Moreover, the condensate is not easily obstructed by the structure of the buffer cup itself during the process of collecting towards the air inlet, so that it flows into the battery cell more thoroughly and replenishes the electrolyte loss in the battery cell to a greater extent.

[0030] In some embodiments, the inner wall of the buffer cup is coated with a hydrophobic coating to reduce the adhesion of condensate to the cup wall.

[0031] By adopting the above solution, the amount of condensate residue in the buffer cup is reduced, allowing more condensate to flow from the air inlet to the battery cells, thus replenishing the electrolyte loss in the battery cells to a greater extent.

[0032] According to another aspect of the embodiments of this application, a battery formation system is provided, comprising:

[0033] In any of the above embodiments, the gas extraction device is used to extract gas from the battery cell, and the heating device is used to heat the battery cell.

[0034] This embodiment of the application sets up a buffer cup and a turbulence-inducing mechanism inside the buffer cup. As the gas flows through the buffer cup, it is turbulent by the turbulence-inducing mechanism, changing its original flow direction. The gas travels a longer path and stays in the buffer cup for a longer time, thereby increasing the probability of the gas contacting the cup wall. This causes the electrolyte vapor in the gas to condense to a greater extent inside the buffer cup. The condensate flows back from the air inlet into the battery cell to replenish the electrolyte and reduce electrolyte loss.

[0035] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more obvious and understandable, specific implementation methods of this application are described below. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the overall structure of the air extraction device provided in one embodiment of this application.

[0038] Figure 2 This is a cross-sectional view of the air extraction device in one embodiment of this application.

[0039] Figure 3 for Figure 2 A schematic diagram of the cross-sectional structure of the AA plane.

[0040] Figure 4 This is a schematic diagram of the turbulence mechanism in one embodiment of this application.

[0041] Figure 5 This is a cross-sectional schematic diagram of an air extraction device according to another embodiment of this application.

[0042] Explanation of reference numerals in the attached drawings: 1. Buffer cup; 2. Air inlet; 3. Air outlet; 4. Baffle mechanism; 40. Air outlet; 41. Fan; 411. Motor; 42. Connector; 421. Lead wire cavity; 43. Wire; 44. Baffle tube; 5. Condensation cavity. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0045] The terms "comprising" and "having," and any variations thereof, used in the specification, claims, and drawings of this application are intended to cover without excluding other meanings. The words "a" or "an" do not exclude the presence of multiples.

[0046] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0047] In this article, the term "and / or" 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 generally indicates that the preceding and following related objects have an "or" relationship.

[0048] The directional terms appearing in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the extraction or formation device of this application. For example, in the description of this application, terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0049] Furthermore, the terms "first," "second," etc., in the specification and claims of this application or in the aforementioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0050] In the description of this application, unless otherwise stated, "multiple" means two or more (including two), and similarly, "multiple groups" means two or more (including two groups).

[0051] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, "connection" or "linkage" in mechanical structures can refer to a physical connection, such as a fixed connection, for example, a connection fixed by fasteners, such as a connection fixed by screws, bolts, or other fasteners; a physical connection can also be a detachable connection, such as a snap-fit ​​or interlocking connection; a physical connection can also be an integral connection, such as a connection formed by welding, bonding, or integral molding. In circuit structures, "connection" or "linkage" can refer not only to a physical connection but also to an electrical connection or a signal connection. For example, it can be a direct connection, i.e., a physical connection, or an indirect connection through at least one intermediate component, as long as the circuit is connected; it can also refer to the internal connection of two components. Signal connection can refer not only to signal connection through a circuit but also to signal connection through a media, such as radio waves. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0052] Formation, a crucial step in lithium-ion battery manufacturing, aims to create a solid electrolyte interphase (SEI) film on the electrode material surface during the initial charge. The performance of the SEI film directly determines the battery's cycle performance and consistency. The formation process involves heating the battery cells and extracting gas from within them to create a negative pressure environment.

[0053] Currently, the method used is to directly extract gas from the battery cell by connecting the extraction device to the electrolyte injection port of the battery cell through a pipe. However, after extracting the gas from the battery cell using the existing extraction method, a large amount of electrolyte is often lost, resulting in poor formation interface within the battery cell and directly affecting the lifespan of the battery cell.

[0054] The inventors discovered through research that the cause of electrolyte loss is the presence of some low-boiling-point solvents in the electrolyte. During the formation process, the temperature of the battery cell is relatively high, which causes some of the solvent in the electrolyte to evaporate and form vapor. While the gas extraction device extracts the gas from the battery cell, it also extracts this part of the electrolyte vapor, resulting in electrolyte loss.

[0055] Electrolyte loss not only affects the quality of individual battery cells but also wastes electrolyte. Furthermore, when electrolyte vapor condenses in the vacuum extraction device, it can corrode the device itself. Therefore, solving the problem of electrolyte loss during the formation process is urgently needed.

[0056] In view of this, embodiments of this application provide a vacuuming device and a formation system, which can condense and return the electrolyte vapor extracted during the formation process to the battery cell, thereby reducing electrolyte loss.

[0057] Figure 1 This is a schematic diagram of the overall structure of the air extraction device provided in one embodiment of this application. Figure 2 This is a cross-sectional view of the air extraction device in one embodiment of this application, as shown below. Figure 1 and Figure 2 As shown, the air extraction device includes a buffer cup 1 and a turbulence mechanism 4.

[0058] The buffer cup 1 has an air inlet 2 and an air outlet 3. The air inlet 2 is used to communicate with the inside of the battery cell so that the gas inside the battery cell can flow to the buffer cup 1. The air outlet 3 is used to connect to a vacuum device so that the gas inside the buffer cup 1 can flow out.

[0059] The turbulence mechanism 4 has an air outlet 40 located inside the buffer cup 1. It is used to blow the gas inside the buffer cup 1 to increase the probability of the gas inside the buffer cup 1 contacting the cup wall of the buffer cup 1, thereby causing the electrolyte vapor to condense on the surface of the cup wall.

[0060] It should be emphasized that, in the absence of external interference, the gas will generally choose a shorter path to flow from the inlet 2 to the outlet 3 and will not deliberately contact the wall of the buffer cup 1. As a result, a large amount of electrolyte vapor will not have time to condense and liquefy in the buffer cup 1 before flowing out from the outlet 3, causing electrolyte loss.

[0061] In some embodiments, the cross-sectional dimension of the buffer cup 1 in the direction perpendicular to the line connecting the air inlet 2 and the air outlet 3 is larger than the diameter of the air inlet 2 and / or the diameter of the air outlet 3. This reduces the flow velocity of the gas within the buffer cup 1 as it flows through it, so that the gas is disturbed by the turbulence mechanism 4 and its flow path is altered.

[0062] The turbulence-disrupting mechanism 4 can be partially or entirely located inside the buffer cup 1. Of course, to achieve the turbulence-disrupting effect, the portion located inside the buffer cup 1 must at least include the air outlet 40 of the turbulence-disrupting mechanism 4. The turbulence-disrupting mechanism 4 can increase the contact probability between the gas inside the buffer cup 1 and the cup wall of the buffer cup 1 by directly blowing the airflow inside the buffer cup 1, or it can increase the contact probability between the gas inside the buffer cup 1 and the cup wall of the buffer cup 1 by introducing external gas. This application embodiment does not limit this, but it should be noted that if the turbulence-disrupting mechanism 4 introduces external gas into the buffer cup 1, the external gas should be a dry gas that will not react with the gas inside the buffer cup 1, such as an inert gas.

[0063] It is worth noting that, since the battery cells are heated during the formation process, the temperature of the gas extracted from the battery cells is generally higher than the temperature of the external environment. When the buffer cup 1 is used in the external environment, the temperature of the cup wall of the buffer cup 1 is lower than the temperature of the gas extracted from the battery cells, so that the electrolyte vapor in the gas condenses when it comes into contact with the cup wall of the buffer cup 1.

[0064] Understandably, to prevent electrolyte leakage from the battery cells, the air inlet 2 of the evacuation device is connected to the top of the battery cell during use, meaning that the air inlet 2 is located below the buffer cup 1 in the operating state. The condensate generated on the wall of the buffer cup 1 flows downwards along the wall, and when it reaches the air inlet 2, it flows back into the battery cell.

[0065] As can be seen, in the above embodiment, the gas extraction device allows the high-temperature gas inside the battery cell to enter the buffer cup 1 from the inlet 2 and then flow out from the outlet 3. During the process of the gas flowing through the buffer cup 1, it is turbulent by the turbulence mechanism 4 inside the buffer cup 1, changing its original flow direction. The gas flows through the buffer cup 1 for a longer path and stays for a longer time, thereby increasing the probability of the gas contacting the cup wall of the buffer cup 1. When the gas contacts the cup wall of the buffer cup 1, the electrolyte vapor condenses due to the temperature difference between the gas and the buffer cup 1. The condensate flows and collects along the cup wall of the buffer cup 1. When the condensate reaches the inlet 2, it flows back into the battery cell from the inlet 2 to replenish the electrolyte and reduce electrolyte loss.

[0066] In some embodiments, the orientation of the air outlet 40 is set at an angle to the first direction P, the angle being greater than 0° and less than 360°; the first direction P is a straight line from the air inlet 2 to the air outlet 3.

[0067] In other words, the orientation of the air outlet 40 of the turbulence mechanism 4 is different from the orientation of the first direction P.

[0068] Without the flow disturbance mechanism 4, the gas will flow from the inlet 2 to the outlet 3 in the buffer cup 1 via the shortest path. During this process, the probability of the gas coming into contact with the cup wall of the buffer cup 1 is relatively small.

[0069] After the turbulence mechanism 4 is set, the turbulence mechanism 4 blows the gas in the buffer cup 1, causing the gas to change its original flow direction, thereby lengthening the flow path in the buffer cup 1, and making it easier to contact the cup wall of the buffer cup 1 during the flow process, thus accelerating the condensation of electrolyte vapor.

[0070] like Figure 2 As shown, in some embodiments, the air inlet 2 and the air outlet 3 are arranged opposite to each other, and the turbulence mechanism 4 is located on the side where the air outlet 3 is located.

[0071] By adopting the above scheme, as the gas flows from the inlet 2 to the outlet 3, the resistance from the turbulence mechanism 4 gradually increases, thereby gradually slowing down the flow speed of the gas, or changing the original flow path and flowing to the outlet 3 in a more tortuous path. During this process, the probability of contact with the wall of the buffer cup 1 is further increased, thereby causing more electrolyte vapor in the gas to condense on the wall of the buffer cup 1, reducing the amount of electrolyte vapor mixed in the gas flowing out of the outlet 3, and reducing electrolyte loss.

[0072] Figure 3 for Figure 2 A schematic diagram of the cross-sectional structure of plane AA. Figure 4 This is a schematic diagram of the turbulence mechanism in one embodiment of this application, as shown below. Figure 2 , Figure 3 and Figure 4 As shown, in some embodiments, the turbulence mechanism 4 includes a fan 41 disposed within the buffer cup 1.

[0073] The fan 41 may have an internally installed battery that drives the motor 411 to rotate, and the motor 411 drives the fan blades to rotate. Alternatively, the fan 41 may be connected to the motor 411 inside the buffer cup 1 via a wire 43, and the wire 43 may be connected to a power source outside the buffer cup 1 to drive the motor 411 to rotate the fan blades. This application embodiment does not limit the specific implementation of the fan 41.

[0074] It should be noted that during use, electrolyte vapor will inevitably condense on the surface of the fan 41. Therefore, the materials of each part of the fan 41 should be made of corrosion-resistant materials as much as possible, or a corrosion-resistant coating should be applied to the surface of each part of the fan 41 to prevent the fan 41 from being corroded and affecting its use.

[0075] In addition, since the motor 411 of the fan 41 needs to be powered during use, the motor 411 can be waterproofed to prevent condensate from entering the motor 411. For example, the surface of the motor 411 is covered with a waterproof membrane.

[0076] By adopting the above scheme, the airflow direction of the fan 41 is more dispersed, the area of ​​influence on the gas in the buffer cup 1 is also larger, and the wind speed of the fan 41 at the same position is constantly changing, which has a better turbulence effect on the gas in the buffer cup 1, and further helps to accelerate the condensation of electrolyte vapor in the buffer cup 1.

[0077] like Figure 2 and Figure 3 As shown, in some embodiments, the fan 41 is at least partially located on the line connecting the air inlet 2 and the air outlet 3.

[0078] By adopting the above scheme, during the process of gas flowing from the inlet 2 to the outlet 3, at least a portion of the gas is directly obstructed by the fan 41 and cannot flow out in a straight direction, thereby changing the gas flow path and increasing the probability of electrolyte vapor contacting the wall of the buffer cup 1 during the path change process.

[0079] like Figure 3 As shown, in some embodiments, along the first direction P, the projection of the fan 41 on the cup wall where the air outlet 3 is located completely covers the projection of the air inlet 2 on the cup wall where the air outlet 3 is located.

[0080] By adopting the above scheme, after the gas enters the buffer cup 1 from the air inlet 2, it is immediately resisted by the fan 41, which further increases the path length of the gas flow in the buffer cup 1 and increases the probability of the gas condensing in the buffer cup 1.

[0081] like Figure 2 As shown, in some embodiments, the air inlet 2, fan 41, and air outlet 3 are located sequentially on the same straight line. This means that the gas entering the buffer cup 1 from the air inlet 2 can only enter the outlet by bypassing the fan 41 from its edge. During the process of bypassing the fan 41, the gas flow path becomes longer, and the gas inevitably comes into contact with the inner wall of the buffer cup 1, causing the electrolyte vapor to condense.

[0082] The following comparison of the test data from Example 1 and Comparative Example 1 further illustrates the effectiveness of the vacuuming device provided in this application during the cell formation process.

[0083] Example 1:

[0084] During the formation process, select Figure 2 The vacuum pumping device shown was used to perform high-temperature vacuum formation on 15 hard-shell lithium-ion battery cells. The inlet 2 of the pumping device was connected to the electrolyte injection port of the battery cell, and the outlet 3 was connected to the vacuum pumping device. The formation temperature was 45℃, and the negative pressure was -70 kPa. The battery cells were weighed before and after formation, and the electrolyte loss after formation was calculated. Electrolyte loss = weight of the battery cell before formation - weight of the battery cell after formation. The experimental results are recorded in the left two columns of Table 1 below.

[0085] Comparative Example 1:

[0086] During formation, 15 hard-shell lithium-ion battery cells with the same specifications as those used in Example 1 were directly subjected to vacuum high-temperature formation using pipelines. One end of the pipeline was connected to the electrolyte injection port of the battery cell, and the other end was connected to the vacuum pump. The formation temperature was 45°C, and the negative pressure was -70 kPa. The battery cells were weighed before and after formation, and the electrolyte loss after formation was calculated using the same calculation method as in Example 1. The experimental results are recorded in the right columns of Table 1 below.

[0087] During the formation process, all other conditions were the same for Example 1 and Comparative Example 1.

[0088] Table 1

[0089]

[0090]

[0091] The values ​​recorded in Table 1 clearly show that, in Example 1, after using the vacuum device described in this application, the amount of electrolyte lost during the formation process is far less than the amount of electrolyte lost when the vacuum device described in this application is not used.

[0092] like Figure 2 , Figure 3 and Figure 4 As shown, in some embodiments, the turbulence mechanism 4 further includes a connector 42 located between the fan 41 and the cup wall of the buffer cup 1, for connecting the fan 41 to the cup wall of the buffer cup 1.

[0093] The connector 42 is positioned to completely avoid the air inlet 2 and the air outlet 3, or not to completely cover the air inlet 2 and / or the air outlet 3, so that the air inlet 2 and the air outlet 3 can be supplied with gas normally. In addition, the shape, structure and installation position of the connector 42 can be set according to the specific space inside the buffer cup 1 without affecting the rotation of the fan 41, and this embodiment does not limit this.

[0094] In some embodiments, the connector 42 is connected to the inner wall of the fan 41 and / or the buffer cup 1 by means of welding or adhesive bonding.

[0095] It should be noted that during use, electrolyte vapor will inevitably condense on the surface of connector 42. Therefore, the material of connector 42 should be as corrosion-resistant as possible, or a corrosion-resistant coating should be applied to the surface of connector 42 to prevent connector 42 from being corroded and aging, thus losing its supporting strength.

[0096] By adopting the above solution, since the fan 41 is connected to the cup wall of the buffer cup 1 through the connector 42, the setting position of the fan 41 is not limited by factors such as the shape and structure of the buffer cup 1, but only needs to consider whether it has a better turbulence effect, thus making the setting of the fan 41 more flexible.

[0097] like Figure 2 , Figure 4 As shown, in some embodiments, the turbulence mechanism 4 further includes a wire 43, one end of which is connected to the motor 411 of the fan 41, and the other end extends through the cup wall of the buffer cup 1 for electrical connection with an external power source; the connector 42 has a lead cavity 421, and the portion of the wire 43 located inside the buffer cup 1 is located inside the lead cavity 421 to prevent gas from corroding the wire 43.

[0098] During the process of wire 43 passing through the cup wall of buffer cup 1, perforations are inevitably generated in the cup wall. In order to prevent air leakage from the perforations, in some embodiments, the perforations are sealed, such as by using sealing plugs, sealing rings, welding, or adhesive sealing.

[0099] By adopting the above scheme, the fan 41 can be turned on or off by an external power source, making the operation of the turbulence mechanism 4 more convenient. In addition, by placing the wire 43 inside the lead wire cavity 421, the wire 43 is less susceptible to corrosion and damage, resulting in a lower failure rate and a longer service life for the air extraction device.

[0100] Figure 5 This is a cross-sectional schematic diagram of the air extraction device in another embodiment of this application, as shown below. Figure 5 As shown, in some embodiments, the turbulence mechanism 4 includes a turbulence pipe 44, the air outlet 40 of which is located inside the buffer cup 1 and the air inlet is located outside the buffer cup 1, for connecting to the air blowing device.

[0101] The blowing device can be a component such as an air pump. The blowing device blows air into the buffer cup 1 through the turbulence pipe 44, thereby disturbing the gas in the buffer cup 1 and increasing the probability that the gas in the buffer cup 1 will contact the buffer cup 1 and condense on the cup wall of the buffer cup 1.

[0102] like Figure 2 , Figure 3 and Figure 5 As shown, in some embodiments, the wall of the buffer cup 1 has a condensation cavity 5, which is used to contain the condensation medium.

[0103] In some embodiments, the condensing medium is water, dry ice, etc.

[0104] In some embodiments, the wall of the buffer cup 1 has a multi-layer structure, and a condensation cavity 5 is formed between two adjacent layers of the wall.

[0105] The condensation chamber 5 can exist on the entire wall of the buffer cup 1, or it can exist only on a portion of the wall of the buffer cup 1.

[0106] Furthermore, the condensing medium can circulate within the condensing chamber 5. For example, the buffer cup 1 has an inlet and an outlet on its wall that connect to the condensing chamber 5. During the formation process, the condensing medium enters the condensing chamber 5 through the inlet and flows out through the outlet. Alternatively, the condensing medium can remain stationary within the condensing chamber 5. For example, the condensing chamber 5 can be closed, preventing the condensing medium from flowing within it.

[0107] By using a condensing medium, the temperature of the buffer cup 1 is further reduced, increasing the temperature difference between the cup wall of the buffer cup 1 and the gas inside the buffer cup 1, thereby accelerating the condensation of the electrolyte vapor.

[0108] like Figure 1 , Figure 2 and Figure 5 As shown, in some embodiments, the buffer cup 1 is a hollow cone or pyramid, and the air inlet 2 is located at the tip of the cone or pyramid to allow condensate to flow out from the air inlet 2.

[0109] The figure only shows an embodiment where the buffer cup 1 is a cone. Those skilled in the art should be able to reasonably imagine that the buffer cup 1 is a pyramid. No further examples are shown in the figures of the embodiments of this application.

[0110] By adopting the above scheme, when the air inlet 2 of the buffer cup 1 is inserted downwards into the battery cell, the condensate in the buffer cup 1 collects on the cup wall and eventually flows into the battery cell from the air inlet 2. Moreover, the condensate is not easily obstructed by the structure of the buffer cup 1 itself during the process of collecting towards the air inlet 2, so that it flows into the battery cell more thoroughly and replenishes the electrolyte loss in the battery cell to a greater extent.

[0111] In some embodiments, the inner wall of the buffer cup 1 is coated with a hydrophobic coating to reduce the adhesion of condensate to the cup wall of the buffer cup 1.

[0112] A hydrophobic coating is a coating on which the static contact angle of water with the coating surface is greater than 90°. For example, the coating material of a hydrophobic coating may include one or more of polytetrafluoroethylene, polyolefin, polycarbonate, polyamide, polyacrylonitrile, and polyester. The hydrophobic coating can reduce the adhesion and residue of condensate in the buffer cup 1, thereby allowing more condensate to flow from the air inlet 2 to the battery cells, thus replenishing the electrolyte loss within the battery cells to a greater extent.

[0113] In summary, the gas extraction device provided in this application embodiment, by setting a buffer cup 1 and a turbulence mechanism 4 inside the buffer cup 1, causes the gas to change its original flow direction during the process of flowing through the buffer cup 1 due to the turbulence effect of the turbulence mechanism 4. The gas flows through the buffer cup 1 for a longer path and stays for a longer time, thereby increasing the probability of the gas contacting the cup wall of the buffer cup 1. As a result, the electrolyte vapor in the gas is condensed to a greater extent inside the buffer cup 1. The condensate flows back from the air inlet 2 into the battery cell to replenish the electrolyte and reduce electrolyte loss.

[0114] According to another aspect of the embodiments of this application, a battery formation system is provided, including a gas extraction device and a heating device as described in any of the above embodiments. The gas extraction device is used to extract gas from the battery cell, and the heating device is used to heat the battery cell.

[0115] Those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0116] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A vacuum device, characterized in that, include: A buffer cup has an air inlet and an air outlet. The air inlet is used to communicate with the component to be vacuumed so that the gas in the battery cell can flow into the buffer cup. The air outlet is used to connect to a vacuum pump so that the gas in the buffer cup can flow out. A turbulence mechanism has an air outlet located inside the buffer cup, which is used to blow the gas inside the buffer cup to increase the probability of the gas inside the buffer cup contacting the cup wall, thereby causing the electrolyte vapor to condense on the cup wall surface. The air inlet and the air outlet are arranged opposite to each other, and the turbulence mechanism is located on the side where the air outlet is located; The buffer cup is a hollow cone or pyramid, and the air inlet is located at the tip of the cone or pyramid to allow condensate to flow out from the air inlet.

2. The air extraction device according to claim 1, characterized in that, The air outlet is oriented at an angle to the first direction; The first direction is a straight line from the air inlet to the air outlet.

3. The air extraction device according to claim 2, characterized in that, The turbulence-disrupting mechanism includes a fan, which is disposed within the buffer cup.

4. The air extraction device according to claim 3, characterized in that, The fan is at least partially located on the line connecting the air inlet and the air outlet.

5. The air extraction device according to claim 3, characterized in that, Along the first direction, the projection of the fan onto the cup wall where the air outlet is located completely covers the projection of the air inlet onto the cup wall where the air outlet is located.

6. The air extraction device according to claim 3, characterized in that, The turbulence mechanism also includes a connector located between the fan and the wall of the buffer cup, for connecting the fan to the wall of the buffer cup.

7. The air extraction device according to claim 6, characterized in that, The turbulence-disrupting mechanism also includes a wire, one end of which is connected to the motor of the fan, and the other end of which passes through the wall of the buffer cup for electrical connection to an external power source. The connector has a lead cavity, and the portion of the wire located inside the buffer cup is located inside the lead cavity to prevent gas from corroding the wire.

8. The air extraction device according to any one of claims 1-7, characterized in that, The airflow disturbance mechanism includes an airflow disturbance tube, the air outlet of which is located inside the buffer cup and the air inlet of which is located outside the buffer cup, for connecting to an air blowing device.

9. The air extraction device according to any one of claims 1-7, characterized in that, The buffer cup has a condensation cavity in its wall for containing the condensing medium.

10. The air extraction device according to any one of claims 1-7, characterized in that, The inner wall of the buffer cup is coated with a hydrophobic coating to reduce the adhesion of condensate to the cup wall.

11. A battery formation system, characterized in that, The device includes the gas extraction device and the heating device as described in any one of claims 1-10, wherein the gas extraction device is used to extract gas from the battery cell and the heating device is used to heat the battery cell.

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