Device and method for accelerating electrolyte infiltration
Patent Information
- Application Number
- CN202411076982.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-07
- Publication Date
- 2026-02-10
AI Technical Summary
The electrolyte wetting of existing lithium/sodium-ion battery cells is difficult, resulting in long injection and wetting times, which affects the cell's cycle performance and safety performance, and also increases manufacturing costs.
The bare cells are baked directly before being placed into the casing. After baking, they are placed directly into the electrolyte tank without being placed into the casing. The electrolyte wetting is accelerated by a combination of negative pressure, electrolyte circulation and vibration equipment. The negative pressure is controlled at -10 to -40 kPa, the vibration frequency is 5 to 200 kHz and the vibration time is 5 to 20 minutes, and this is repeated multiple times.
It significantly shortens the electrolyte wetting time, improves the efficiency of cell electrolyte injection, enhances the electrolyte wetting effect and cell quality, and reduces manufacturing costs.
Smart Images
Figure CN121507115A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of new energy batteries, and particularly relates to a method and device for accelerating electrolyte infiltration. BACKGROUND
[0002] Lithium / sodium ion batteries are rechargeable batteries, and the battery cell of a lithium / sodium ion battery is a secondary battery cell that can be repeatedly charged and discharged, which is composed of main components such as cathode and anode sheets, separator membranes, electrolytes, and mechanical parts. At present, the volume of the battery cell of a lithium / sodium ion battery is getting larger and larger, and the energy density requirement of the battery cell is getting higher and higher, but the test on the manufacturing process is also getting larger and larger. First, the internal theoretical residual space of the battery cell with high energy density has been compressed to the extreme, so it is difficult to inject liquid; second, the main material is a high-pressure dense material with small porosity, which is not conducive to electrolyte infiltration; third, the areal density is also inclined to higher thickness design, so the electrolyte infiltration path is lengthened.
[0003] The above three reasons combined together greatly increase the difficulty of injection and infiltration, and also lead to the problem of poor infiltration and lithium precipitation in the process, thereby affecting the cycle performance and safety performance of the battery cell.
[0004] The existing process is to cool the battery cell after high-temperature baking for a period of time, then inject liquid, and then high-temperature soak for ten or more hours. The injection and infiltration time is long, the battery cell injection efficiency is low, the production capacity is greatly reduced, and the manufacturing cost is increased.
[0005] It is hoped to provide an improved electrolyte infiltration method and device, in particular, to provide a method and device for accelerating the electrolyte infiltration process and improving the battery cell injection work efficiency. SUMMARY
[0006] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a method for accelerating electrolyte infiltration, which aims to improve the battery cell injection work efficiency of a rechargeable battery.
[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a method for accelerating electrolyte infiltration, comprising the steps of:
[0008] S1, baking a bare battery cell;
[0009] S2, after the baking is completed, the bare battery cell is cooled;
[0010] S3, placing the cooled bare battery cell into an electrolyte tank for infiltration.
[0011] The step S3 comprises:
[0012] S301, adding electrolyte into the electrolyte tank, starting electrolyte circulation function of the electrolyte tank, making electrolyte flow until the liquid level in the electrolyte tank reaches a set value;
[0013] S302, pausing electrolyte circulation, starting negative pressure, and making the electrolyte tank in a negative pressure environment;
[0014] S303, closing the negative pressure, starting a vibration device, and vibrating the electrolyte tank.
[0015] In the step S301, the electrolyte flows into the electrolyte tank from the injection port arranged at a specified position of the electrolyte tank, and the flow direction of the electrolyte is from the side to the direction parallel to the top of the tank.
[0016] The injection port is arranged in multiple.
[0017] In the step S302, the negative pressure value of the electrolyte tank is controlled at-10 to-40 kPa.
[0018] In the step S302, the duration of making the electrolyte tank in a negative pressure environment is 10 to 30 min.
[0019] In the step S303, the amplitude of vibrating the electrolyte tank is controlled at 5 to 200 kHz.
[0020] In the step S303, the vibration time of vibrating the electrolyte tank is controlled at 5 to 20 min.
[0021] The step S3 further comprises:
[0022] S304, executing the steps S301 to S303 again.
[0023] The application further provides a device for accelerating electrolyte infiltration.
[0024] The method for accelerating electrolyte infiltration of the application directly enters an oven before the battery cell enters a shell, greatly reducing the hindering effect of the aluminum shell on the baking efficiency; after the battery cell is baked, the battery cell does not enter the shell and directly enters the electrolyte tank for infiltration, solving the problems of difficult first liquid injection, long liquid injection time, and long infiltration time, improving the battery cell liquid injection work efficiency, and improving the electrolyte infiltration effect and the battery cell quality of lithium / sodium ion batteries. BRIEF DESCRIPTION OF DRAWINGS
[0025] The present specification includes the following drawings, and the contents shown are as follows:
[0026] Figure 1 It is a flow chart of the method for accelerating electrolyte infiltration of the application;
[0027] Figure 2 is a top view of the simple device (omitting the trachea distribution map contained in the upper cover);
[0028] Figure 3 is a front view of the simple device;
[0029] Figure 4 is a capacity distribution comparison chart of Example 1 and Comparative Example 1;
[0030] Figure 5 is a resistance distribution comparison chart of Example 1 and Comparative Example 1;
[0031] In the figure, the following are marked: 1, upper cover; 2, outer groove body; 3, inner groove body; 4, integrated air extraction pipeline; 5, top cover; 6, liquid level limiting hole; 7, liquid injection port; 8, liquid level observation instrument; 9, bare battery cell; 10, electrolyte injection pipe. DETAILED DESCRIPTION
[0032] The specific embodiments of the present application will be further described below with reference to the accompanying drawings, and the purpose is to help the technical personnel in the field to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present application, and to help its implementation.
[0033] As shown in Figure 1 , the present application provides a method for accelerating electrolyte infiltration, comprising the following steps:
[0034] S1, baking the bare battery cell;
[0035] S2, after the baking is completed, the bare battery cell is cooled;
[0036] S3, the cooled bare battery cell is placed in an electrolyte tank for infiltration.
[0037] Specifically, in the present application, the bare battery cell before entering the shell (the bare battery cell lacks an outer shell body) is directly placed in an oven for baking without entering the shell, the baking process is consistent with the prior art, and the baked bare battery cell is directly placed in a sealed box filled with electrolyte. The box is subjected to one or a combination of micro-negative pressure, vibration table vibration and electrolyte circulation flow to accelerate electrolyte infiltration, thereby greatly accelerating the electrolyte infiltration effect. The well-infiltrated battery cell is entered into the shell to supplement the liquid, and then enters the next process.
[0038] By using the method of the present application, the bare battery cell is directly placed in an oven before entering the shell, thereby greatly reducing the hindering effect of the aluminum shell on the baking efficiency. After baking, the battery cell is directly placed in an electrolyte tank for infiltration without entering the shell, thereby solving the problems of difficult one-time injection, long injection time and long infiltration time, improving the electrolyte infiltration effect, and improving the battery cell quality.
[0039] In the above step S1, the bare battery cell is baked in an oven.
[0040] In the above step S2, after the baked bare battery cell is taken out from the oven, it is placed in a cooling area for temperature cooling until the temperature of the bare battery cell is reduced to 28-45℃.
[0041] The above step S3 includes:
[0042] S301, add electrolyte to the electrolyte tank, start the electrolyte circulation function of the electrolyte tank, make the electrolyte flow, until the liquid level in the electrolyte tank reaches the set value;
[0043] S302, electrolyte circulation is suspended, start negative pressure, make the electrolyte tank in a negative pressure environment;
[0044] S303, close the negative pressure, start the vibration device, and vibrate the electrolyte tank;
[0045] S304, execute steps S301-S303 again.
[0046] As shown in Figure 2 and Figure 3 , in the above step S301, it is noted that the electrolyte circulation is started first in the electrolyte tank, and the electrolyte flows in from the liquid injection port 7 provided at the specified position of the electrolyte tank (for example, the oblique upper side of the electrolyte tank, that is, the intersection of the tank top and the side wall of the electrolyte tank), and the flow direction of the electrolyte is from the side to the parallel direction of the tank top. Avoiding the electrolyte from washing the pole piece and causing the pole piece to fall off.
[0047] As shown in Figure 2 and Figure 3 , as a preferred, the liquid injection port 7 is provided with multiple liquid injection ports 7, which are distributed on both sides of the positive and negative poles of the bare battery cell, and the electrolyte is added into the electrolyte tank through each liquid injection port 7 at the same time, accelerating the infiltration effect.
[0048] As shown in Figure 2 and Figure 3 , in the above step S301, when the liquid level in the electrolyte tank reaches the lower end of the plastic under the top cover 5, the excess electrolyte in the inner tank body 3 will flow out of the other outer tank body 2, and then the excess electrolyte will be recycled into the electrolyte tank, reducing the loss of electrolyte. The electrolyte in the electrolyte tank is consumed by about 1 / 5 before entering the next step, which can be calculated by the liquid level of the outer tank body 2.
[0049] In the above step S301, the direction of electrolyte circulation is from top to bottom, because the upper part is always in a liquid-lean state, and needs to be continuously supplemented with electrolyte. The flow rate of the electrolyte is controlled in the range of ≤0.5L / min, and too high flow rate will generate more bubbles and will wash away the powder on the pole piece.
[0050] In the above step S302, by pumping the electrolyte tank, the negative pressure value of the electrolyte tank is controlled at -10 to -40 kPa, and the actual standard is not to suck out the electrolyte. The purpose is to remove the bubbles formed between the electrode sheets during the electrolyte circulation. The duration of the electrolyte tank in the negative pressure environment is set to 10 to 30 min, which can be determined by the bubbling behavior in the air pipe transition cup whether to enter the next process.
[0051] In the above step S303, the vibration device is a small vibration table, and the electrolyte tank is placed on the vibration device. The amplitude of the vibrating electrolyte tank is controlled at 5 to 200 kHz. Too large amplitude will cause the tab to break. Moreover, the direction of vibration is limited. The vibration direction can only be horizontal vibration in front and back and left and right when the bare cell is placed vertically. The bare cell cannot be vibrated up and down. Up and down vibration will cause the electrode sheet in the bare cell to slide up and down, resulting in that the anode cannot cover the cathode or the isolation film cannot cover the anode, thereby causing product safety hazards. The front and back and left and right vibration cannot be performed at the same time, and the sequence has no specific requirement. Moreover, the vibration time of the vibrating electrolyte tank is controlled at 5 to 20 min.
[0052] In the above step S304, steps S301 to S303 are executed again, and the number of repeated execution of steps S301 to S303 is 1 to 6 times. According to the volume of the cell, there will be some difference, and the best judgment standard is the disassembly result.
[0053] In the above step S3, the temperature control of infiltration needs to be performed: the temperature of the electrolyte tank is controlled in the range of 28 to 45 degrees. Too low temperature is not conducive to infiltration, and too high temperature will accelerate the volatilization loss of electrolyte.
[0054] In the above step S3, the bare cell is not put into the shell: the bare cell not put into the shell is immersed in the electrolyte tank, which can avoid the problem that the small space and less electrolyte in the aluminum shell disturb the electrolyte infiltration of the electrode sheet.
[0055] In the above step S3, measures such as negative pressure extraction, electrolyte circulation and vibration table vibration are taken to accelerate infiltration, which can achieve the best balance point of cost and infiltration time.
[0056] In the above step S3, negative pressure extraction: negative pressure extraction in the electrolyte pool is to remove the gas between the electrode sheet gaps and accelerate infiltration, and the micro-bubbles generated during the electrolyte circulation movement; and the negative pressure range is -10 to -40 kPa. Too small negative pressure will not completely extract the bubbles, and too large negative pressure will take away the electrolyte, causing waste of electrolyte and damage to the air pipe.
[0057] In the above step S3, electrolyte circulation and vibration table vibration: electrolyte flow and vibration table vibration can reduce the contact angle between the electrode sheet and the electrolyte, destroy the surface tension, and accelerate the infiltration.
[0058] The above-mentioned method for accelerating electrolyte wetting has the following advantages:
[0059] 1. This method is simple and easy to implement.
[0060] 2. The principle is simple and the modification time is short.
[0061] 3. It shortens the soaking time in the battery cell manufacturing process and also speeds up the baking time.
[0062] 4. Significantly improved cell interface.
[0063] 5. Costs are controllable and the operation is highly feasible.
[0064] like Figure 2 and Figure 3 As shown, the present invention also provides an apparatus for accelerating electrolyte wetting. The apparatus is applied in the above-mentioned method for accelerating electrolyte wetting. The apparatus includes a vibrating device and an electrolyte tank, with the electrolyte tank placed on the vibrating device.
[0065] like Figure 2 and Figure 3 As shown, the electrolyte tank includes an outer tank body 2, an inner tank body 3, and a top cover 1. The inner tank body 3 is installed in the inner cavity of the outer tank body 2 and is used to accommodate multiple bare battery cells. The top cover 1 is used to close the top opening of the outer tank body 2. The top cover 1 is located above the inner tank body 3. The top cover 5 of the bare battery cell can be locked onto the top of the inner tank body 3 to keep the bare battery cell in a vertical position.
[0066] like Figure 3 As shown, the top of the inner tank 3 is provided with a liquid level limiting hole 6 and a liquid injection port 7.
[0067] like Figure 3 As shown, an integrated vacuum pipe 4 is provided on the upper cover 1. The integrated vacuum pipe 4 is connected to a vacuum generator. The integrated vacuum pipe 4 has multiple vacuum ports, each of which is located above a bare battery cell inside the inner tank 3. The vacuum generator is used to create a vacuum. After the vacuum generator is started, it evacuates the electrolyte tank through the integrated vacuum pipe 4, so that the electrolyte tank is in a negative pressure state.
[0068] The electrolyte tank is connected to the main electrolyte pipeline, which is equipped with a main electrolyte valve. Opening the main electrolyte valve allows electrolyte to be poured into the electrolyte tank. For example... Figure 3As shown, a liquid level observer 8 is connected to the outer tank 2. The surface of the liquid level observer 8 has multiple scale lines and corresponding scale values. The liquid level observer 8 is made of transparent material and has a hollow interior. The lower end of the liquid level observer 8 is connected to the bottom of the outer tank 2, and the inner cavity of the liquid level observer 8 is connected to the inner cavity of the outer tank 2. The electrolyte in the outer tank 2 can enter the interior of the liquid level observer 8 through the lower opening. During the process of filling the electrolyte tank, the liquid level height inside the liquid level observer 8 can be determined in real time.
[0069] Example 1
[0070] Tooling preparation: Connect the electrolyte tank to the main electrolyte pipeline and the main air pressure pipeline. The entire device is placed in the high-temperature settling room inside the drying room of the production line. The drying room is the traditional production site used for baking, liquid injection and other processes, and its ambient temperature and humidity are strictly controlled.
[0071] Experimental verification process: 1. Prepare 50 230Ah lithium iron phosphate aluminum-cased cells to be baked. Note that the bare cells are in an uncased state, but the top cover 5 and the outer Mylar protective film are assembled. Then, put the bare cells into the baking oven for baking. During baking, the temperature inside the baking oven is set to 100±5℃ until the moisture content of the bare cells is qualified, and then the baking is stopped. Record the baking time t1.
[0072] 2. After baking, remove the bare battery cells from the baking oven and place them in the cooling area. Then record the time from when the bare battery cells are removed until their temperature drops to 28-45°C as t2.
[0073] 3. Place the electrolyte tank. The electrolyte tank has several empty slots. In this example, there are 48 empty slots, which is exactly the same as the number of battery cells in a furnace cavity.
[0074] Then start the electrolyte wetting process:
[0075] a. Open the main electrolyte valve and fill the electrolyte tank with electrolyte until the scale line of the external electrolyte observation column is 5. Then close the main electrolyte valve and start the electrolyte circulation until the electrolyte level drops to 4. Then close the electrolyte circulation.
[0076] b. Activate the negative pressure in the tank, controlling the negative pressure value between -10 and -40 kPa. In practice, the negative pressure gradually decreases to -40 kPa and then stabilizes, with a decreasing frequency of -10 kPa / min. Observe the air bubbles in the trachea until they stop escalating or after 30 minutes, then turn off the negative pressure.
[0077] c. Start the vibration table and vibrate for 5 minutes each in the forward and backward and left and right directions. The vibration frequency is 5 to 200 kHz. Note that the vibration frequency also increases in steps until it stabilizes at 200 kHz, with an increase rate of 50 kHz / min.
[0078] d. Repeat steps a, b, and c, and record the time t3 for each cycle. After each cycle, disassemble the battery cell to check the wetting effect until the wetting is qualified. The time for each cycle is t31, t32, t33, and so on.
[0079] In this example, the battery cell volume is not very large, and it is basically qualified after two cycles.
[0080] 4. A summary of all time records is shown in Table 1. Compared with Comparative Example 1, the total time saved is 6.28 hours, which is a significant saving.
[0081] 5. Insert the bare battery cell into the casing and laser weld the aluminum casing to the top cover 5.
[0082] 6. Perform normal formation, aging, sealing, and capacity testing on the battery cells. Simultaneously compare the electrical performance of the cells to prevent negative impacts from the manufacturing process. Performance comparisons are shown in the appendix. Figure 4 and 5 The data shows that the process has no negative impact on the electrical performance of the battery cells and improves the consistency of electrical performance. This phenomenon is strongly correlated with more thorough wetting.
[0083] Comparative Example 1
[0084] In the comparative example, a conventional process was used to inject electrolyte into a 230Ah lithium iron phosphate aluminum-cased battery cell. The specific process is as follows.
[0085] Experimental Verification Process: 1. Prepare 50 230Ah lithium iron phosphate aluminum-cased cells to be baked, then place them in a baking oven at a temperature set at 100±5℃ until the water content is within acceptable limits. Record the baking time as t1. 2. Remove the baked cells from the baking oven and place them in a cooling area until the cell temperature drops to 25±5℃. Record the cooling time as t2. 3. Liquid Injection: Push the cooled cells to the liquid injection position and begin the liquid injection process. Record the time from the start to the end of liquid injection as t3. 4. Transfer the cells to a high-temperature (45±5℃) settling chamber for immersion. After a period of time, disassemble the cells to confirm whether they are properly immersed. Record the time from the start to the end of immersion as t4. A summary of all time records is shown in Table 1. 5. Perform normal formation, aging, sealing, and capacity testing on the cells.
[0086] Table 1 (Comparison of Process Time):
[0087]
[0088] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.
Claims
1. A method for accelerating electrolyte wetting, characterized in that, Including the following steps: S1. Bake the bare battery cells; S2. After baking, the bare battery cells are cooled. S3. Place the cooled bare battery cell into the electrolyte tank for immersion.
2. The method for accelerating electrolyte wetting according to claim 1, characterized in that, Step S3 includes: S301. Add electrolyte to the electrolyte tank, and start the electrolyte circulation function of the electrolyte tank to make the electrolyte flow until the liquid level in the electrolyte tank reaches the set value. S302. Electrolyte circulation is paused, and negative pressure is started to put the electrolyte tank in a negative pressure environment. S303. Turn off the negative pressure and start the vibration equipment to vibrate the electrolyte tank.
3. The method for accelerating electrolyte wetting according to claim 2, characterized in that, In step S301, the electrolyte flows in from the injection port set at a designated position in the electrolyte tank, and the electrolyte flows in from the side into the tank in a direction parallel to the top of the tank.
4. The method for accelerating electrolyte wetting according to claim 3, characterized in that, The injection port is provided in multiple locations.
5. The method for accelerating electrolyte wetting according to any one of claims 2 to 4, characterized in that, In step S302, the negative pressure value of the electrolyte tank is controlled between -10 and -40 kPa.
6. The method for accelerating electrolyte wetting according to any one of claims 2 to 4, characterized in that, In step S302, the electrolyte tank is kept in a negative pressure environment for 10 to 30 minutes.
7. The method for accelerating electrolyte wetting according to any one of claims 2 to 4, characterized in that, In step S303, the amplitude of vibration when vibrating the electrolyte tank is controlled between 5 and 200 kHz.
8. The method for accelerating electrolyte wetting according to any one of claims 2 to 4, characterized in that, In step S303, the vibration time when vibrating the electrolyte tank is controlled to be between 5 and 20 minutes.
9. The method for accelerating electrolyte wetting according to any one of claims 2 to 8, characterized in that, Step S3 further includes: S304. Repeat steps S301 to S303.
10. A device for accelerating electrolyte wetting, characterized in that, The device is used in the method for accelerating electrolyte wetting as described in any one of claims 1 to 9.