Method for soaking an electrode assembly

Abstract

The present invention provides a method for wetting an electric core. The method includes: Step S1, loading the electric core on a feeding tray; Step S2, tilting the feeding tray at a first inclination angle to combine the liquid injection hole with the liquid storage cup; Step S3, returning the feeding tray to the upright position, and injecting an excessive amount of electrolyte in the liquid storage cup into the electric core through a hole provided at the bottom of the liquid storage cup; shifting the liquid injection cup above the liquid storage cup, and then supplementing the electrolyte into the liquid storage cup through the liquid injection cup; Step S4, inflating and deflating the electric core to complete the positive and negative pressure cycle; Step S5, tilting the feeding tray at a second inclination angle to discharge the excess electrolyte in the electric core into the liquid storage cup; Step S6, separating the liquid injection hole from the liquid storage cup, and returning the feeding tray to the upright position to complete wetting. Using the method of the present application helps to shorten the wetting time of the electric core and improve the wetting effect.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage, and in particular, to a method for wetting an electrode core. Background Art

[0002] As a common energy storage device, the battery is widely used in various energy storage scenarios. Liquid injection is a key step in manufacturing the battery. At present, due to the fixation of the housing and the electrode core, in order to avoid slow liquid injection, usually a two-time liquid injection method of first injection and second injection is adopted to prevent the electrolyte from flowing out of the liquid injection hole due to untimely absorption. Usually, after the first injection and the second injection, each electrode core is not filled to avoid liquid leakage during detachment. In the prior art, usually 85% of the first injection + 15% of the second injection or 90% of the first injection + 10% of the second injection is adopted. After the first liquid injection, the liquid injection level of the battery accounts for about 1 / 5 of the electrode core. Taking LFP280 as an example, the liquid injection height is 4 cm and the housing height is 20 cm. However, when injecting liquid, the electrode core is in a non-rich liquid state, and the absorption during standing can only be carried out from the lower part. The liquid level will drop after the electrode core absorbs liquid through the wound core, and then gas will be introduced during the positive and negative pressure cycle, affecting local wetting and forming large brown spots. As the capacity and compaction of the electrode core increase, the wetting becomes slower and slower, and the conventional wetting method needs to be innovated.

[0003] The wetting of the electrode sheet does not mean the wetting of the wound core. The wetting of the wound core depends on many factors such as tightness and temperature. At present, the reliable means are to measure ICP element characterization and ultrasonic testing. However, the ultrasonic probe equipment is expensive and the position cannot be determined clearly, and the distribution state of the electrolyte cannot be observed by the naked eye. In the prior art, usually the residual liquid is measured by disassembling to determine the liquid absorption amount or the dry wound core is directly used to absorb liquid to confirm the liquid absorption amount. However, the disassembly process is cumbersome, the liquid absorption amount error is large, and it is impossible to confirm whether the outer circle is wetted properly; the liquid absorption of the wound core is relatively microscopic and difficult to characterize. Bubbles introduced during disassembly cannot be confirmed whether they are original bubbles or introduced during disassembly; it can accurately characterize the liquid injection of the electrode sheet, diaphragm or wound core stack under conventional liquid injection, but there are few characterizations of the wetting of the rich liquid state of the wound core, and there is a lack of corresponding detection means. Summary of the Invention

[0004] The main purpose of the present invention is to provide a method for wetting an electrode core to solve the problems of long wetting time and poor wetting effect existing in the method for wetting an electrode core in the prior art.

[0005] To achieve the above object, according to one aspect of the present invention, a method for soaking an electric core is provided. The method includes: Step S1, loading the electric core on a feeding tray, with the bottom of the electric core in contact with the feeding tray and parallel to the horizontal direction; Step S2, a liquid injection hole is provided at the top of the electric core. By tilting the feeding tray at a first inclination angle, the liquid injection hole is combined with a liquid storage cup placed at the first inclination angle; Step S3, returning the feeding tray to the upright position, and injecting an excessive amount of electrolyte into the electric core through a hole provided at the bottom of the liquid storage cup; shifting the liquid injection cup above the liquid storage cup, and then supplementing the electrolyte into the liquid storage cup through the liquid injection cup; a receiving hole for receiving the electrolyte is provided on one side of the liquid storage cup away from the liquid injection hole, and an adjustable stopper is provided at the receiving hole for adjusting the opening and closing state of the receiving hole; Step S4, inflating and deflating the electric core to complete a positive and negative pressure cycle; Step S5, tilting the feeding tray at a second inclination angle to discharge the excess electrolyte in the electric core into the liquid storage cup; Step S6, separating the liquid injection hole from the liquid storage cup, returning the feeding tray to the upright position, and completing the soaking.

[0006] Further, in the above step S3, the injection amount of the electrolyte in the electric core is 20% - 50% more than the theoretical full injection amount.

[0007] Further, in the above step S4, the positive pressure of the positive and negative pressure cycle is 0.2 - 0.8 MPa; and / or, the negative pressure of the positive and negative pressure cycle is -90 - -30 kPa; and / or, the number of positive and negative pressure cycles is 3 - 8 times.

[0008] Further, in the above step S2, when the feeding tray is tilted at the first inclination angle, the included angle between the bottom of the electric core and the horizontal direction is 60° - 90°; and / or, in step S5, when the feeding tray is tilted at the second inclination angle, the included angle between the bottom of the electric core and the horizontal direction is 60° - 100°.

[0009] Further, when the feeding tray is tilted at the first inclination angle, the included angle between the bottom of the electric core and the horizontal direction is 90°.

[0010] Further, when the feeding tray is tilted at the second inclination angle, the included angle between the bottom of the electric core and the horizontal direction is determined according to the required discharge amount of the electrolyte.

[0011] Further, in the above step S3, the injection speed of the electrolyte into the electric core is 500 mL / min - 1 L / min; and / or, in step S5, the discharge speed of the excess electrolyte is 50 mL / min - 200 mL / min.

[0012] Further, the above step S6 further includes statically treating the electric core in the returned feeding tray, and the static treatment time is 12 - 16 h to complete the soaking.

[0013] Further, a simulated battery cell is selected for wettability monitoring. Before injecting an excessive amount of electrolyte into the simulated battery cell, step S3 further includes adding a fluorescent agent to the electrolyte; after the wetting is completed, the simulated winding core in the simulated battery cell is taken out and unfolded, and the simulated winding core is irradiated with a fluorescent lamp, and the wetting condition of the simulated winding core is observed through the fluorescent area. The larger the fluorescent area, the more sufficient the wetting.

[0014] Further, the concentration of the fluorescent agent in the above-mentioned electrolyte is 1.3 - 2.6 mg / mL; and / or, the type of the fluorescent agent is selected from any one or more of FITC, Cy2, Cy3, and Alexa Fluor 647.

[0015] Applying the technical solution of the present invention, in step S2, tilting the incoming material tray at a first tilt angle to combine the liquid injection hole with the liquid storage cup helps to subsequently inject the electrolyte in the liquid storage cup into the battery cell through the liquid injection hole. In step S3, the electrolyte in it is excessively injected into the battery cell through the hole provided at the bottom of the liquid storage cup, so that the electrolyte fills the entire battery cell and the entire winding core is soaked, which helps to improve the speed at which the battery cell absorbs the electrolyte and helps to reduce the risk of gas entrapment. Since the electrolyte forms a seal on the liquid level surface, it helps to reduce the risk of external gas introduction under the air flow. An adjustable stopper is provided at the receiving hole, which helps to control the time of receiving the electrolyte and facilitates the regulation of the liquid level of the electrolyte. In step S4, positive and negative pressure cycling is performed on the battery cell after injection, which helps to further improve the speed at which the battery cell absorbs the electrolyte. In step S5, tilting the incoming material tray at a second tilt angle to discharge the excess electrolyte in the battery cell into the liquid storage cup, on the one hand, makes the electrolyte perform longitudinal wetting on the battery cell and wet in the direction of the thickness of the electrode sheet, which helps to further improve the wetting efficiency; on the other hand, it helps to accelerate the discharge of the excess electrolyte, thus helping to shorten the wetting time. The liquid storage cup receives the discharged electrolyte and can use the electrolyte for the next round of liquid injection, which helps to reduce the liquid injection cost. Description of the Drawings

[0016] The specification drawings constituting a part of the present application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0017] Figure 1 Shows an optical photograph of the simulated winding core in Example 1 of the present application under the irradiation of a fluorescent lamp. Detailed Embodiments

[0018] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0019] As analyzed in the background art of this application, there are problems of long soaking time and poor soaking effect of the battery cell in the prior art. To solve the above problems, this application provides a method for soaking a battery cell.

[0020] In a typical embodiment of this application, a method for soaking a battery cell is provided. The method includes: Step S1, loading the battery cell on the incoming material tray, with the bottom of the battery cell in contact with and parallel to the horizontal direction on the incoming material tray; Step S2, there is a liquid injection hole at the top of the battery cell. By tilting the incoming material tray at a first inclination angle, the liquid injection hole is combined with a liquid storage cup placed at the first inclination angle; Step S3, returning the incoming material tray to the upright position, and injecting an excessive amount of electrolyte in the liquid storage cup into the battery cell through the hole at the bottom of the liquid storage cup; shifting the liquid injection cup above the liquid storage cup, and then supplementing the electrolyte into the liquid storage cup through the liquid injection cup; there is a receiving hole for receiving the electrolyte on one side of the liquid storage cup away from the liquid injection hole, and an adjustable stopper is provided at the receiving hole for adjusting the opening and closing state of the receiving hole; Step S4, inflating and exhausting air in the battery cell to complete the positive and negative pressure cycle; Step S5, tilting the incoming material tray at a second inclination angle to drain the excess electrolyte in the battery cell into the liquid storage cup; Step S6, disengaging the liquid injection hole from the liquid storage cup, and returning the incoming material tray to the upright position to complete the soaking.

[0021] In Step S2, tilting the incoming material tray at a first inclination angle to combine the liquid injection hole with the liquid storage cup helps to inject the electrolyte in the liquid storage cup into the battery cell through the liquid injection hole subsequently. In Step S3, injecting an excessive amount of electrolyte in the liquid storage cup into the battery cell through the hole at the bottom of the liquid storage cup makes the electrolyte fill the entire battery cell, and the entire wound core is soaked, which helps to increase the speed of the battery cell absorbing the electrolyte and helps to reduce the risk of gas entrapment. Since the electrolyte forms a seal on the liquid level surface, it helps to reduce the risk of external gas introduction under the air flow. The adjustable stopper provided at the receiving hole helps to control the time of receiving the electrolyte and facilitates the regulation of the liquid level of the electrolyte. In Step S4, performing a positive and negative pressure cycle on the battery cell after injection helps to further increase the speed of the battery cell absorbing the electrolyte. In Step S5, tilting the incoming material tray at a second inclination angle to drain the excess electrolyte in the battery cell into the liquid storage cup, on the one hand, makes the electrolyte perform longitudinal soaking on the battery cell, soaking in the direction of the thickness of the electrode plate, which helps to further improve the soaking efficiency; on the other hand, it helps to accelerate the drainage of the excess electrolyte, thus helping to shorten the soaking time. The liquid storage cup receiving the drained electrolyte can use the electrolyte for the next round of injection, which helps to reduce the injection cost.

[0022] In an embodiment of the present application, in the above step S3, a manually operable cover is provided at the hole at the bottom of the liquid storage cup. A sealed rubber ring is provided between the cover and the hole. When the liquid storage cup is tilted, the cover is closed to cover the hole, preventing the electrolyte from leaking out through the hole at the bottom of the liquid storage cup. When injecting the liquid, the cover is opened to inject the electrolyte in the liquid storage cup into the battery cell.

[0023] In an embodiment of the present application, in the above step S3, an adjustable stopper is provided at the receiving hole. A sealed rubber ring is provided between the stopper and the receiving hole. When the electrolyte does not need to be received, the stopper is pushed to cover the receiving hole. When the electrolyte needs to be received, the stopper is pushed to separate from the receiving hole.

[0024] In an embodiment of the present application, in the above step S3, the injection amount of the electrolyte in the battery cell is 20% - 50% more than the theoretical full injection amount, which helps to further improve the speed of the wound core absorbing the electrolyte, improve the wetting effect and reduce the risk of gas entrapment.

[0025] The purpose of the positive and negative pressure cycling is to accelerate the wetting of the battery cell by the electrolyte. To better exert the above-mentioned effects, in an embodiment of the present application, in the above step S4, the positive pressure of the positive and negative pressure cycling is 0.2 - 0.8 MPa; and / or, the negative pressure of the positive and negative pressure cycling is -90 - -30 kPa; and / or, the number of positive and negative pressure cycling times is 3 - 8 times.

[0026] Controlling the positive pressure of the positive and negative pressure cycling, the negative pressure of the positive and negative pressure cycling and the number of positive and negative pressure cycling times within the above ranges helps to further improve the speed of the wound core absorbing the electrolyte.

[0027] In an embodiment of the present application, in the above step S2, the incoming material tray is tilted at a first tilt angle such that the bottom of the battery cell forms an angle of 60° - 100° with the horizontal direction; and / or, in step S5, the incoming material tray is tilted at a second tilt angle such that the bottom of the battery cell forms an angle of 60° - 90° with the horizontal direction.

[0028] By controlling the angle between the bottom of the battery cell and the horizontal direction within the above range during the first tilt angle tilt, it helps to improve the efficiency and stability of the combination of the injection hole and the liquid storage cup, thus ensuring production stability. By controlling the angle between the bottom of the battery cell and the horizontal direction within the above range during the second tilt angle tilt, it helps to improve the wetting degree of the electrolyte on the battery cell and the efficiency of discharging the excess electrolyte.

[0029] To further improve the efficiency of the combination of the injection hole and the liquid storage cup, in an embodiment of the present application, the incoming material tray is tilted at a first tilt angle such that the bottom of the battery cell forms an angle of 90° with the horizontal direction.

[0030] In an embodiment of the present application, the tilting speed of the first tilting angle is 5° / min to 10° / min.

[0031] By controlling the tilting speed of the first tilting angle within the above range, it helps to shorten the time for the liquid injection hole to combine with the liquid storage cup while maintaining the overall stability of the battery cell.

[0032] In an embodiment of the present application, the incoming material tray is tilted at a second tilting angle such that the angle between the bottom of the battery cell and the horizontal direction is determined according to the required discharge amount of the electrolyte.

[0033] In order to better control the discharge amount of the electrolyte, when the discharge amount of the electrolyte is small, the angle of the second tilt is also small. Specifically, when the discharge amount of the electrolyte is A, the incoming material tray is tilted at a second tilting angle such that the angle between the bottom of the battery cell and the horizontal direction is θ. When A < 20% of the injection amount, 60° ≤ θ < 70°; when 20% ≤ A < 40% of the injection amount, 70° ≤ θ < 80°; when 40% ≤ A of the injection amount, 80° ≤ θ ≤ 90°.

[0034] In an embodiment of the present application, the tilting speed of the second tilting angle is 3° / min to 5° / min.

[0035] Controlling the tilting speed of the second tilting angle within the above range helps to improve the discharge efficiency of the excess electrolyte while ensuring the stability of the electrolyte in the battery cell. At the same time, it also plays a better role in promoting the complete infiltration of the electrolyte.

[0036] In an embodiment of the present application, in the above step S3, the injection speed of the electrolyte into the battery cell is 500 mL / min to 1 L / min; and / or, in step S5, the discharge speed of the excess electrolyte is 50 mL / min to 200 mL / min.

[0037] If the injection speed of the electrolyte into the battery cell is too high, it is not conducive to the discharge of gas in the battery cell. If the injection speed of the electrolyte into the battery cell is too low, it is not conducive to improving the injection efficiency of the electrolyte. Controlling the injection speed of the electrolyte into the battery cell within the above range helps to improve the injection efficiency. If the discharge speed of the excess electrolyte is too slow, it is not conducive to shortening the discharge time. If the discharge speed of the excess electrolyte is too fast, it is not conducive to the full infiltration of the electrolyte into the battery cell. Controlling the discharge speed of the excess electrolyte within the above range helps to improve the infiltration efficiency of the battery cell while shortening the discharge time.

[0038] In an embodiment of the present application, the above step S6 further includes statically treating the battery cell in the returned-to-normal incoming material tray. The static treatment time is 12 to 16 h to complete infiltration.

[0039] The static treatment helps the electrolyte to fully and evenly infiltrate the positive and negative materials and the separator of the battery cell, helps the electrolyte to form a stable solid electrolyte interface film on the electrode surface, and thus helps to improve the cycle stability and service life of the battery cell. Controlling the static treatment time within the above range helps to improve the efficiency of the static treatment.

[0040] In an embodiment of the present application, the receiving hole is a circular receiving hole. Setting it as a circular receiving hole helps to improve the efficiency of electrolyte reception.

[0041] In an embodiment of the present application, the liquid injection cup is displaced above the liquid storage cup by a manipulator; and / or, the replenishment speed of the replenished electrolyte is 100 mL / min to 500 mL / min.

[0042] The operation of displacing the liquid injection cup by a manipulator enables the hole at the bottom of the liquid injection cup to be combined with the hole at the top of the liquid storage cup to replenish the electrolyte into the liquid storage cup through the liquid injection cup, which helps to reduce labor costs. Controlling the replenishment speed of the replenished electrolyte within the above range helps to control the volume of the electrolyte in the liquid storage cup, thereby helping to control the injection amount of the electrolyte in the liquid storage cup into the battery cell, and further helping to improve the injection efficiency.

[0043] In an embodiment of the present application, an analog battery cell can also be selected for wettability monitoring (the analog battery cell can be normally arranged in the battery cell array). Before injecting an excessive amount of electrolyte into the analog battery cell, step S3 further includes adding a fluorescent agent to the electrolyte; after the infiltration is completed, the analog winding core in the analog battery cell is taken out and unfolded, and the analog winding core is irradiated with a fluorescent lamp. The wettability of the analog winding core is observed through the fluorescent area. The larger the fluorescent area, the more sufficient the infiltration. When the fluorescent area accounts for more than 95% of the analog winding core, it is considered qualified.

[0044] During the production process of the battery cell, by selecting an analog battery cell for wettability monitoring, it helps to observe the wettability of the battery cell. By adding a fluorescent agent to the electrolyte, under the irradiation of the fluorescent lamp, the fluorescent agent can emit fluorescence, and the part of the winding core infiltrated by the electrolyte can emit fluorescence under the irradiation of the fluorescent lamp. The wettability of the electrolyte in the winding core can be confirmed through the fluorescing part, thereby obtaining the wettability of the battery cell after the injection is completed. The wettability of the analog winding core can guide the adjustment of the process parameters for the infiltration of the battery cell to adjust the optimal process parameters.

[0045] In addition, the above analog battery cell can be used for adjusting process parameters before the production of the battery cell, and can also be arranged in the battery cell array during normal production for real-time monitoring of the wettability of the battery cell.

[0046] In order to improve the accuracy of wettability monitoring, in one embodiment of the present application, the concentration of the fluorescent agent in the above electrolyte is 1.3 to 2.6 mg / mL; and / or, the type of the fluorescent agent is selected from any one or more of FITC, Cy2, Cy3, and Alexa Fluor 647.

[0047] In order to make the simulated battery cell closer to the actual battery cell and reduce the cost of battery cell production, in one embodiment of the present application, the simulated wound core in the above simulated battery cell has a winding structure formed by winding a stack of separator - positive electrode - separator - negative electrode 1.5 turns around the wound core. The shape of the winding structure is the same as that of the actual wound core, both being oval. The simulated wound core is placed in a transparent plastic housing to form the simulated battery cell.

[0048] Placing the simulated wound core in the transparent plastic housing helps to observe the wetting condition of the wound core in real time, and the cost of the plastic housing is lower than that of the actual aluminum shell, making it easier to take out the simulated wound core after wetting is completed.

[0049] The beneficial effects of the present application will be further described below in conjunction with embodiments.

[0050] Embodiment 1

[0051] Load the battery cell on the incoming material tray. The bottom of the battery cell contacts and is set on the incoming material tray, and the bottom of the battery cell is parallel to the horizontal direction. There is a liquid injection hole at the top of the battery cell. By tilting the incoming material tray at a first inclination angle, the liquid injection hole is combined with the liquid storage cup. The angle between the bottom of the battery cell and the horizontal direction is 90°. The tilting speed of the first inclination angle is 5° / min. Return the incoming material tray to the upright position, and inject an excessive amount of electrolyte in it into the battery cell through the hole at the bottom of the liquid storage cup. Shift the liquid injection cup above the liquid storage cup by a manipulator, and then supplement the electrolyte in the liquid storage cup through the liquid injection cup. One side of the liquid storage cup away from the liquid injection hole has a receiving hole for receiving the electrolyte from, and an adjustable stop is provided at the receiving hole to adjust the opening and closing state of the receiving hole. Inject an electrolyte that is 20% excessive compared to the theoretical full filling amount into the battery cell through the liquid storage cup. The injection speed of the electrolyte into the battery cell is 500 mL / min, and supplement the electrolyte in the liquid storage cup through the liquid injection cup at a speed of 500 mL / min. Perform positive and negative pressure cycling on the battery cell after injection. The positive pressure of the positive and negative pressure cycling is 0.4 MPa, the negative pressure of the positive and negative pressure cycling is -60 kPa, and the number of positive and negative pressure cycling times is 5 times. After the positive and negative pressure cycling is completed, tilt the incoming material tray at a second inclination angle to drain the excess electrolyte in the battery cell into the liquid storage cup. Tilting the incoming material tray at the second inclination angle makes the angle between the bottom of the battery cell and the horizontal direction 70°. The tilting speed of the second inclination angle is 3° / min. When draining 20% of the injected amount of electrolyte in the battery cell, the drainage speed of the excess electrolyte is 50 mL / min. The liquid storage cup receives the drained electrolyte. After the excess electrolyte is drained, let the battery cell stand. The standing time is 14 h to complete infiltration. Complete the processes of liquid injection, positive and negative pressure cycling, draining excess electrolyte, and infiltration treatment in sequence according to the above process. The wound core is a simulated wound core with a wound structure formed by winding 1.5 turns in a laminated manner of separator - positive electrode - separator - negative electrode. The housing of the simulated battery cell is a transparent plastic shell. After the infiltration treatment is completed, unfold the simulated wound core and observe the infiltration situation of the simulated wound core by irradiating with a fluorescent lamp. The unfolded length of the simulated wound core is 51 cm, and the width is 18.7 cm. The observed infiltration situation is as Figure 1 shown.

[0052] Example 2

[0053] The difference from Example 1 is that the electrolyte injection amount is 50% excessive compared to the theoretical full filling amount.

[0054] Example 3

[0055] The difference from Example 1 is that the electrolyte injection amount is 10% excessive compared to the theoretical full filling amount.

[0056] Example 4

[0057] The difference from Example 1 is that the positive pressure of the positive and negative pressure cycle is 0.8 MPa, the negative pressure of the positive and negative pressure cycle is -90 kPa, and the number of positive and negative pressure cycles is 8 times.

[0058] Example 5

[0059] The difference from Example 1 is that the positive pressure of the positive and negative pressure cycle is 0.2 MPa, the negative pressure of the positive and negative pressure cycle is -30 kPa, and the number of positive and negative pressure cycles is 3 times.

[0060] Example 6

[0061] The difference from Example 1 is that the positive pressure of the positive and negative pressure cycle is 0.6 MPa, the negative pressure of the positive and negative pressure cycle is -20 kPa, and the number of positive and negative pressure cycles is 2 times.

[0062] Example 7

[0063] The difference from Example 1 is that the standing treatment time is 16 h.

[0064] Example 8

[0065] The difference from Example 1 is that the standing treatment time is 12 h.

[0066] Example 9

[0067] The difference from Example 1 is that the standing treatment time is 10 h.

[0068] Example 10

[0069] The difference from Example 1 is that the incoming material tray is tilted at the first tilt angle so that the bottom of the battery cell makes an angle of 60° with the horizontal direction, and tilted at the second tilt angle so that the bottom of the battery cell makes an angle of 80° with the horizontal direction.

[0070] Example 11

[0071] The difference from Example 1 is that the incoming material tray is tilted at the first tilt angle so that the bottom of the battery cell makes an angle of 50° with the horizontal direction, and tilted at the second tilt angle so that the bottom of the battery cell makes an angle of 50° with the horizontal direction.

[0072] Example 12

[0073] The difference from Example 1 is that the tilting speed of the first tilt angle is 10° / min, and the tilting speed of the second tilt angle is 5° / min.

[0074] Example 13

[0075] The difference from Example 1 is that the tilting speed of the first tilting angle is 15° / min, and the tilting speed of the second tilting angle is 4° / min.

[0076] Example 14

[0077] The difference from Example 1 is that the injection speed of the electrolyte into the battery cell is 1 L / min, the discharge speed of the excess electrolyte is 200 mL / min, and the replenishment speed of the replenished electrolyte is 100 mL / min.

[0078] Example 15

[0079] The difference from Example 1 is that the injection speed of the electrolyte into the battery cell is 1.5 L / min, the discharge speed of the excess electrolyte is 300 mL / min, and the replenishment speed of the replenished electrolyte is 50 mL / min.

[0080] Comparative Example 1

[0081] The difference from Example 1 is that it is injected according to the theoretical liquid injection volume of the battery.

[0082] The simulated core wetting conditions and the saturated liquid absorption amount of the battery cells in the above examples and comparative examples are shown in Table 1.

[0083] Table 1

[0084]

[0085] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0086] In step S2, the incoming tray is tilted at a first inclination angle to combine the liquid injection hole with the liquid storage cup, which helps to inject the electrolyte in the liquid storage cup into the battery cell through the liquid injection hole in the subsequent process. In step S3, the electrolyte in the liquid storage cup is over-injected into the battery cell through the hole provided at the bottom of the liquid storage cup, so that the electrolyte fills the entire battery cell and the entire wound core is soaked, which helps to improve the speed at which the battery cell absorbs the electrolyte and helps to reduce the risk of gas entrapment. Since the electrolyte seals the liquid level surface, it helps to reduce the risk of external gas introduction under the airflow. An adjustable stopper is provided at the receiving hole, which helps to control the time of receiving the electrolyte and facilitates the regulation of the electrolyte liquid level. In step S4, the battery cell after liquid injection is subjected to positive and negative pressure cycling, which helps to further improve the speed at which the battery cell absorbs the electrolyte. In step S5, the incoming tray is tilted at a second inclination angle to discharge the excess electrolyte in the battery cell into the liquid storage cup. On the one hand, the electrolyte becomes a longitudinal infiltration of the battery cell, infiltrating in the direction of the thickness of the electrode sheet, which helps to further improve the infiltration efficiency; on the other hand, it helps to accelerate the discharge of the excess electrolyte, thus helping to shorten the infiltration time. The liquid storage cup receives the discharged electrolyte and can use the electrolyte for the next round of liquid injection, which helps to reduce the liquid injection cost.

[0087] The above are only embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for soaking an electric core, characterized in that, The method includes: Step S1, loading the battery cell on the incoming material tray, with the bottom of the battery cell in contact with and parallel to the horizontal direction on the incoming material tray; Step S2, there is a liquid injection hole at the top of the battery cell. By tilting the incoming material tray at a first inclination angle, the liquid injection hole is combined with a liquid storage cup placed at the first inclination angle; Step S3, straightening the incoming material tray, and injecting an excessive amount of electrolyte into the battery cell through a hole at the bottom of the liquid storage cup; shifting the liquid injection cup above the liquid storage cup, and then supplementing the electrolyte into the liquid storage cup through the liquid injection cup; one side of the liquid storage cup away from the liquid injection hole has a receiving hole for receiving the electrolyte, and an adjustable stopper is provided at the receiving hole for adjusting the opening and closing state of the receiving hole; Step S4, inflating and deflating the battery cell to complete the positive and negative pressure cycle; Step S5, by tilting the incoming material tray at a second inclination angle, discharging the excess electrolyte in the battery cell into the liquid storage cup; Step S6, separating the liquid injection hole from the liquid storage cup, straightening the incoming material tray, and completing the infiltration; The injection amount of the electrolyte in the battery cell is 20% - 50% more than the theoretical full injection amount.

2. The method according to claim 1, characterized in that, In step S4, the positive pressure of the positive and negative pressure cycle is 0.2 - 0.8 MPa; and / or, the negative pressure of the positive and negative pressure cycle is -90 - -30 kPa; and / or, the number of positive and negative pressure cycles is 3 - 8 times.

3. The method according to claim 1, wherein In step S2, when the incoming material tray is tilted at the first inclination angle, the included angle between the bottom of the battery cell and the horizontal direction is 60° - 100°; and / or, in step S5, when the incoming material tray is tilted at the second inclination angle, the included angle between the bottom of the battery cell and the horizontal direction is 60° - 90°.

4. The method according to claim 3, wherein When the incoming material tray is tilted at the first inclination angle, the included angle between the bottom of the battery cell and the horizontal direction is 90°.

5. The method according to claim 3, characterized in that, When the incoming material tray is tilted at the second inclination angle, the included angle between the bottom of the battery cell and the horizontal direction is determined according to the discharge amount required for the electrolyte.

6. The method according to any one of claims 1 to 5, characterized in that, In step S3, the injection speed of the electrolyte into the battery cell is 500 mL / min - 1 L / min; and / or, in step S5, the discharge speed of the excess electrolyte is 50 mL / min - 200 mL / min.

7. The method according to any one of claims 1 to 5, characterized in that Step S6 further includes statically treating the battery cell in the straightened incoming material tray, and the static treatment time is 12 - 16 h to complete the infiltration.

8. The method according to any one of claims 1 to 5, characterized in that Select a simulated battery cell for infiltration monitoring. Before injecting an excessive amount of electrolyte into the simulated battery cell, step S3 further includes adding a fluorescent agent to the electrolyte; After the infiltration is completed, take out and unfold the simulated wound core in the simulated battery cell, irradiate the simulated wound core with a fluorescent lamp, and observe the infiltration situation of the simulated wound core through the fluorescent area. The larger the fluorescent area, the more sufficient the infiltration.

9. The method according to claim 8, characterized in that, The concentration of the fluorescent agent in the electrolyte is 1.3 to 2.6 mg / mL; and / or, the model of the fluorescent agent is selected from any one or more of FITC, Cy2, Cy3, and Alexa Fluor 647.

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