Battery monomer and preparation method thereof, battery device, electric equipment and energy storage equipment
By combining staged negative and positive pressure electrolyte injection with rotational speed control, the problem of electrolyte penetration into the cell was solved, improving the electrolyte injection efficiency and consistency of large-capacity batteries, enhancing electrode wetting, and improving battery performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-18
- Publication Date
- 2026-03-27
AI Technical Summary
When preparing large-capacity prismatic batteries using traditional liquid injection methods, the electrolyte is difficult to fully penetrate into the cell, resulting in low injection efficiency and poor consistency, especially in thick-coated systems and high-density electrodes.
Electrolyte injection is carried out in a multi-stage negative and positive pressure environment, combined with different rotation speeds, including negative pressure venting, positive pressure wetting and rotation treatment. This gradually removes gas and promotes electrolyte penetration. The wetting effect of the electrolyte is improved by gradient negative and positive pressure treatment.
It significantly improves the liquid injection and wetting effect and efficiency of large-capacity batteries, improves the penetration of high-viscosity electrolyte in high-voltage solid electrodes, avoids black spots on electrodes, and improves electrical performance and utilization efficiency of active materials.
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Figure CN121748738A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of electrochemical energy storage, in particular to a battery cell, a preparation method thereof, a battery device, an electric equipment and an energy storage equipment. BACKGROUND
[0002] At present, when a large-capacity square shell battery is prepared by using a traditional liquid injection method, the electrolyte is difficult to fully penetrate into the inside of the battery cell, the liquid injection efficiency is low and the consistency is poor, which is more prominent especially on the battery cell with a thick coating system and the battery cell with an electrode with high compaction density. This is mainly because there are two technical problems in the liquid injection link of the large-capacity square shell lithium battery: first, the electrolyte is not fully infiltrated, which will cause black spots on the electrode sheet; second, the high-viscosity electrolyte is difficult to penetrate in the high-compaction electrode sheet. SUMMARY
[0003] Therefore, it is necessary to provide a battery cell, a preparation method thereof, a battery device, an electric equipment and an energy storage equipment to solve the problem that the electrolyte is difficult to fully penetrate into the inside of the electrode during the liquid injection of the large-capacity square shell battery, resulting in low efficiency and poor consistency.
[0004] The first aspect of the present application provides a preparation method of a battery cell, and the scheme is as follows:
[0005] A preparation method of a battery cell, comprising the following steps:
[0006] The battery cell semi-finished product is subjected to electrolyte injection in multiple stages to obtain an injection cell, wherein the injection process in each stage includes: first, placing the corresponding semi-finished product in a negative pressure environment for exhaust treatment, then injecting the semi-finished product after exhaust, and placing it in a positive pressure environment for infiltration treatment of the electrolyte after injection;
[0007] The injection cell is subjected to rotation treatment at different speeds, the rotation treatment includes first rotation at a speed of 10 rpm to 14 rpm and second rotation at a speed of 18 rpm to 30 rpm, and the second rotation is performed after the first rotation.
[0008] In some embodiments, during the exhaust treatment in each stage, the negative pressure environment pressure of the next stage is lower than that of the previous stage.
[0009] In some embodiments, during the infiltration treatment in each stage, the positive pressure environment pressure of the next stage is higher than that of the previous stage.
[0010] In some embodiments, the injection is performed in two stages.
[0011] In some embodiments, the gas pressure of the negative pressure environment during the first stage of the injection process is -70kPa~-90kPa, and the injection is performed after maintaining for 5min~10min.
[0012] The gas pressure of the negative pressure environment during the second stage of the injection process is -80kPa~-100kPa, and the injection is performed after maintaining for 80s~160s.
[0013] In some embodiments, the first stage injection amount is 50%~80% of the total electrolyte amount, and the remaining electrolyte is injected in the second stage.
[0014] In some embodiments, the gas pressure of the positive pressure environment during the first stage of the injection process is +40kPa~+60kPa, and the injection is performed after maintaining for 3min or more.
[0015] The gas pressure of the positive pressure environment during the second stage of the injection process is +70kPa~+90kPa, and the injection is performed after maintaining for 30s~80s.
[0016] In some embodiments, the method further comprises a step of performing multiple alternating pressure relief treatment and pressure increase treatment on the obtained semi-finished product after the infiltration treatment in the positive pressure environment of the last stage.
[0017] In some embodiments, the gas pressure of each time of the pressure relief treatment is independently controlled to be +0kPa~+5kPa and maintained for 3s~10s.
[0018] The gas pressure of each time of the pressure increase treatment is independently controlled to be +70kPa~+90kPa and maintained for 30s~80s.
[0019] In some embodiments, the pressure relief treatment is performed at least 5 times.
[0020] In some embodiments, the rotating treatment of the injection monomer at different rotating speeds is a segmented rotating treatment at different rotating speeds, and the rotating speed of the latter segment is higher than that of the former segment.
[0021] In some embodiments, the rotating treatment is performed in 3 segments at different rotating speeds, wherein the first segment is rotated at a rotating speed of 10rpm~14rpm for 30s~60s, the second segment is rotated at a rotating speed of 14rpm~18rpm for 60s~120s, and the third segment is rotated at a rotating speed of 18rpm~30rpm for 60s~120s.
[0022] In some embodiments, the electrolyte comprises lithium salt with a mass fraction of 5%~38%, solvent with a mass fraction of 60%~90%, and additives with a mass fraction of 2%~10%.
[0023] In some embodiments, the additive includes perfluoropolyetheramine and polyethylene glycol dioleate, wherein the perfluoropolyetheramine has a mass fraction of 0.3% to 0.6% in the electrolyte and the polyethylene glycol dioleate has a mass fraction of 1% to 2% in the electrolyte.
[0024] The second aspect of this application is to provide a single battery cell, as follows:
[0025] A battery cell is obtained by the battery cell preparation method described in any of the above embodiments.
[0026] The third aspect of this application is to provide a battery device, the solution of which is as follows:
[0027] A battery device includes the aforementioned battery cell, and the battery device includes one or more of the following: battery module, battery pack, and energy storage battery.
[0028] The fourth aspect of this application is to provide an electrical appliance, the solution of which is as follows:
[0029] An electrical device includes the battery device described above, the battery device being used to provide electrical energy.
[0030] The fourth aspect of this application is to provide an energy storage device, the solution of which is as follows:
[0031] An energy storage device includes the aforementioned battery device for storing electrical energy.
[0032] Compared with traditional solutions, the above-mentioned battery cells, their preparation methods, battery devices, electrical equipment, and energy storage devices have the following advantages:
[0033] The aforementioned battery cell preparation method involves multiple stages of electrolyte injection into the battery cell precursor. In the first stage, a negative pressure environment expels gas from the macroscopic pores of the electrode. Post-injection pressurization promotes electrolyte penetration into the small pores and deep pores of the electrode surface. In subsequent stages, a negative pressure environment expels air bubbles remaining in the electrode micropores, and post-injection pressurization further promotes electrolyte wetting of the electrode. After injection, many pores in the electrode remain unabsorbed by electrolyte. Rotating the battery cell at a relatively low speed of 10-14 rpm promotes electrolyte absorption in the larger pores. As the larger pores are filled, the electrolyte effectively wets the electrode. Increasing the rotation speed to 18-30 rpm further penetrates the smaller and deeper pores of the electrode, improving the rate and uniformity of electrolyte penetration. This battery cell preparation method effectively improves the wetting effect and injection efficiency of high-capacity batteries.
[0034] The above-mentioned method for preparing battery cells can improve the penetration effect of high-viscosity electrolyte in high-voltage solid electrode sheets, improve the problem of black spots on the electrode sheets caused by insufficient electrolyte wetting, and thus improve its electrical performance. Attached Figure Description
[0035] Figure 1 This is a schematic flowchart of a method for preparing a single battery cell according to one embodiment;
[0036] Figure 2 This is a schematic diagram of a two-stage injection process in one embodiment;
[0037] Figure 3 This is a schematic diagram of a process involving three segments with different rotational speeds in one embodiment;
[0038] Figure 4 This is a graph showing the gas pressure changes during the injection process in Example 1;
[0039] Figure 5 This is a graph showing the rotational speed change during the rotational treatment in Example 1. Detailed Implementation
[0040] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein; these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.
[0041] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number or order of the indicated technical features.
[0042] 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 is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0043] In the description of this application, "+xkPa" means that the air pressure is higher than the standard atmospheric pressure by xkPa, and "-xkPa" means that the air pressure is lower than the standard atmospheric pressure by xkPa.
[0044] like Figure 1 As shown, a method for preparing a single battery cell according to one embodiment includes the following steps:
[0045] Step S1 involves injecting electrolyte into the semi-finished battery cells in multiple stages to obtain injected cells. The electrolyte injection process at each stage includes: first, placing the corresponding semi-finished product in a negative pressure environment for venting, then injecting electrolyte into the vented semi-finished product, and finally placing it in a positive pressure environment for electrolyte wetting.
[0046] Step S2 involves rotating the injection unit at different speeds. The rotation includes a first rotation at 10-14 rpm and a second rotation at 18-30 rpm. The second rotation occurs after the first rotation.
[0047] The aforementioned battery cell preparation method involves multiple stages of electrolyte injection into the battery cell precursor. In the first stage, a negative pressure environment expels gas from the macroscopic pores of the electrode. Post-injection pressurization promotes electrolyte penetration into the small pores and deep pores of the electrode surface. In subsequent stages, a negative pressure environment expels air bubbles remaining in the electrode micropores, and post-injection pressurization further promotes electrolyte wetting of the electrode. After injection, many pores in the electrode remain unabsorbed by electrolyte. Rotating the battery cell at a relatively low speed of 10-14 rpm promotes electrolyte absorption in the larger pores. As the larger pores are filled, the electrolyte effectively wets the electrode. Increasing the rotation speed to 18-30 rpm further penetrates the smaller and deeper pores of the electrode, improving the rate and uniformity of electrolyte penetration. This battery cell preparation method effectively improves the wetting effect and injection efficiency of high-capacity batteries.
[0048] The above-mentioned method for preparing battery cells can improve the penetration effect of high-viscosity electrolyte in high-voltage solid electrode sheets, improve the problem of black spots on the electrode sheets caused by insufficient electrolyte wetting, and thus improve its electrical performance.
[0049] In some examples, during the venting process at each stage, the negative pressure environment pressure in the later stage is lower than that in the earlier stage. For instance, during the first stage of liquid injection, the negative pressure environment pressure is -70 kPa to -90 kPa, specifically -70 kPa, -75 kPa, -80 kPa, -85 kPa, and -90 kPa. In subsequent stages of liquid injection, the pressure gradient of the negative pressure environment decreases by 5 kPa to 20 kPa, and further by 5 kPa to 15 kPa, specifically 5 kPa, 7 kPa, 10 kPa, 12 kPa, 15 kPa, 17 kPa, and 20 kPa.
[0050] In the example above, gradient negative pressure venting gradually removes shallow and deep gases, reducing residual air bubbles. The first stage uses a higher negative pressure to expel shallow, easily flowing air from the battery cell semi-finished product, while the second stage uses a lower negative pressure to more thoroughly expel gases from deeper areas such as electrode micropores and separator gaps. This reduces gas obstruction during electrolyte injection, allowing the electrolyte to fill all corners more quickly. Simultaneously, gradient negative pressure venting avoids damage to the internal structure of the battery cell semi-finished product caused by excessively low negative pressure before electrolyte injection, such as preventing electrode material detachment and electrode deformation.
[0051] In some examples, during the infiltration treatment at each stage, the positive pressure environment pressure in the later stage is higher than that in the earlier stage. For instance, during the first stage of liquid injection, the positive pressure environment pressure is +40 kPa to +60 kPa, specifically +40 kPa, +45 kPa, +50 kPa, +55 kPa, and +60 kPa. In subsequent stages of liquid injection, the pressure gradient of the positive pressure environment increases by 5 kPa to 20 kPa, and further by 5 kPa to 15 kPa, specifically 5 kPa, 7 kPa, 10 kPa, 12 kPa, 15 kPa, 17 kPa, and 20 kPa.
[0052] In the example above, a gradient positive pressure wetting method is used. In the initial stage, a lower positive pressure is applied to push the electrolyte to fill the macroscopic gaps inside the battery, completing the initial wetting and avoiding direct impact from high pressure that could cause electrolyte splashing or uneven distribution. As the electrolyte gradually covers the electrode surface, the higher positive pressure in the later stage generates a stronger thrust, penetrating deeper areas such as electrode micropores and separator gaps, allowing the electrolyte to fully contact the active materials. Simultaneously, gradient positive pressure wetting avoids damage to the internal structure of the battery cell semi-finished product caused by excessively high positive pressure when the initial electrolyte volume is small, such as preventing electrode material detachment or electrode deformation.
[0053] In some examples, the injection is performed in 2 to 5 stages in step S1. This achieves good injection wetting effect and injection efficiency. To obtain even higher injection efficiency, the injection is performed in 2 to 3 stages.
[0054] In some examples, in step S1, the electrolyte injection is performed in two stages. Further, the first stage injects 50% to 80% of the total electrolyte volume, specifically, for example, 50%, 55%, 60%, 65%, 70%, 75%, 80%, etc. The second stage injects the remaining electrolyte.
[0055] In some examples, during the first stage of liquid injection, the negative pressure environment is maintained at -70 kPa to -90 kPa, specifically -70 kPa, -75 kPa, -80 kPa, -85 kPa, and -90 kPa. The semi-finished battery cell is held in this negative pressure environment for 5 to 10 minutes before liquid injection, specifically for 5, 6, 7, 8, 9, and 10 minutes. By selecting these negative pressures and holding times, gas in the macroscopic pores of the electrode is effectively expelled with high efficiency.
[0056] In some examples, during the second-stage liquid injection process, the negative pressure environment is maintained at -80 kPa to -100 kPa, specifically -80 kPa, -85 kPa, -90 kPa, -95 kPa, and -100 kPa. The semi-finished battery cells are held in this negative pressure environment for 80 to 160 seconds before liquid injection, specifically 80 seconds, 100 seconds, 120 seconds, 140 seconds, and 160 seconds. By selecting these negative pressures and holding times, gas from the small pores and deep pores on the electrode surface is effectively and efficiently expelled.
[0057] In some examples, during the first stage of electrolyte injection, the positive pressure environment is maintained at +40 kPa to +60 kPa, specifically +40 kPa, +45 kPa, +50 kPa, +55 kPa, and +60 kPa. The semi-finished battery cells are held in this positive pressure environment for at least 3 minutes, such as 3 to 8 minutes, specifically 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, and 8 minutes. By selecting the above positive pressure and holding time, the electrolyte can enter the macroscopic pores of the electrode more effectively and efficiently.
[0058] In some examples, during the second-stage electrolyte injection process, the positive pressure environment is maintained at +70 kPa to +90 kPa, specifically +70 kPa, +75 kPa, +80 kPa, +85 kPa, and +90 kPa. The semi-finished battery cells are held in this positive pressure environment for 30 to 80 seconds, specifically 30 seconds, 40 seconds, 50 seconds, 60 seconds, 70 seconds, and 80 seconds. By selecting the above positive pressure and holding time, the electrolyte can effectively penetrate the small pores and deep pores on the electrode surface with high efficiency.
[0059] like Figure 2 As shown, in some examples, step S1 includes:
[0060] Step S11: Place the battery cell semi-finished product in a negative pressure environment of -70kPa to -90kPa for degassing treatment, and keep it for 5min to 10min.
[0061] Step S12: Inject liquid into the semi-finished product after venting, with the injection volume being 50% to 80% of the total electrolyte volume.
[0062] Step S13: Place the semi-finished product after electrolyte injection in a positive pressure environment of +40kPa to +60kPa for electrolyte immersion treatment for 3min to 8min.
[0063] Step S14: Place the semi-finished product that has undergone the first liquid injection process in a negative pressure environment of -80kPa to -100kPa for degassing treatment, and keep it for 80s to 160s.
[0064] Step S15: Inject the remaining electrolyte into the semi-finished product after venting.
[0065] Step S16: Place the semi-finished product after liquid injection in a positive pressure environment of +70kPa~+90kPa for electrolyte wetting treatment, and keep it for 30s~80s to obtain the liquid-injected monomer.
[0066] In some examples, the preparation method of the battery cell also includes the step of subjecting the obtained semi-finished product to multiple alternating depressurization and pressurization treatments after impregnation under positive pressure in the final stage.
[0067] In the example above, alternating pressure relief and pressurization generate pressure pulses. During pressurization, the electrolyte is pushed into deeper micropores, while during pressure relief, the liquid flows back, replenishing the surrounding electrolyte and forming a microcirculation. This ensures that unwetted areas are fully in contact with the electrolyte. Simultaneously, the alternating pressure promotes electrolyte flow within the battery, eliminating uneven electrolyte concentrations or distribution, and ensuring consistent wetting across all areas.
[0068] During pressure relief, the pressure for each step is independently controlled to be +0 kPa to +5 kPa, specifically +0 kPa, +1 kPa, +2 kPa, +3 kPa, +4 kPa, etc. The battery cell semi-finished product is maintained under the above pressure for 3s to 10s, specifically 3s, 4s, 5s, 6s, 7s, 8s, 9s, 10s, etc.
[0069] During pressurization, the pressure for each step is independently controlled to be +70kPa to +90kPa, specifically +70kPa, +75kPa, +80kPa, +85kPa, +90kPa, etc. The semi-finished battery cells are held under this pressure for 30s to 80s, specifically 30s, 40s, 50s, 60s, 70s, 80s, etc.
[0070] In some examples, at least five depressurization processes are performed during the alternating depressurization and pressurization steps described above. In some examples, five to eight depressurization processes are performed during the alternating depressurization and pressurization steps described above.
[0071] In some examples, during step S2, when the injection unit is rotated, the rotating shaft passes through the injection unit, for example, the injection unit rotates around its own axis. For instance, the injection unit is rotated by a turntable, with the injection unit positioned at the center of rotation of the turntable.
[0072] In some examples, in step S2, the process of rotating the injection monomer at different speeds is to perform segmented rotation at different speeds, with the speed of the later segment being higher than that of the earlier segment.
[0073] In some examples, step S2 involves three segments of rotation at different speeds. For example... Figure 3 As shown, step S2 includes:
[0074] Step S21: Rotate at a speed of 10 rpm to 14 rpm for 30 s to 60 s.
[0075] Step S22: Rotate at a speed of 14 rpm to 18 rpm for 60 s to 120 s.
[0076] Step S23: Rotate at a speed of 18 rpm to 30 rpm for 60 s to 120 s.
[0077] The rotation speed of the first segment is 10 rpm to 14 rpm, specifically 10 rpm, 11 rpm, 12 rpm, 13 rpm, 14 rpm, etc. The rotation time of the first segment is 30 s to 60 s, specifically 30 s, 35 s, 40 s, 45 s, 50 s, 55 s, 60 s, etc. The rotation speed of the second segment is 14 rpm to 18 rpm, specifically 14 rpm, 15 rpm, 16 rpm, 17 rpm, 18 rpm, etc. The rotation time of the second segment is 60 s to 120 s, specifically 60 s, 70 s, 80 s, 90 s, 100 s, 110 s, 120 s, etc. The rotation speed of the third segment is 18 rpm to 30 rpm, specifically 18 rpm, 20 rpm, 22 rpm, 25 rpm, 28 rpm, 30 rpm, etc. The rotation time for the third segment is 60s to 120s, specifically 60s, 70s, 80s, 90s, 100s, 110s, and 120s. The rotation processes at different speeds can be connected by increasing the speed, or by setting rotation intervals, where the rotation is paused after the previous segment before proceeding to the next segment at a higher speed.
[0078] In some examples, the electrolyte comprises a lithium salt, a solvent, and additives. In some examples, the lithium salt has a mass fraction of 5% to 38%, specifically 5%, 10%, 15%, 20%, 25%, 30%, 35%, etc. The solvent has a mass fraction of 60% to 90%, specifically 60%, 65%, 70%, 75%, 80%, 90%, etc. The additive has a mass fraction of 2% to 10%, specifically 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, etc.
[0079] For example, lithium salts include, but are not limited to, at least one of lithium hexafluorophosphate (LiPF6), lithium bisfluorosulfonylimide (LiFSI), lithium bistrifluoromethanesulfonylimide (LiTFSI), lithium bis(oxalateborate)borate (LiBOB), lithium bis(oxalateborate)borate (LiODFB), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonylimide (LiNTf2), etc.
[0080] For example, the solvent may include, but is not limited to, at least one of ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), γ-butyrolactone (GBL), methyl acetate (MA), ethyl propionate (EP), etc.
[0081] In some examples, the additives include perfluoropolyetheramine (PFPE-NH2) and polyethylene glycol dioleate (PEG-DOA). The perfluoropolyetheramine has a mass fraction of 0.3% to 0.6% in the electrolyte, specifically, for example, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, etc. The polyethylene glycol dioleate has a mass fraction of 1% to 2% in the electrolyte, specifically, for example, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, etc.
[0082] In the examples above, the combined use of perfluoropolyetheramine and polyethylene glycol dioleate significantly reduces the surface tension of the electrolyte and the contact angle between the electrolyte and the electrode, thereby improving the wetting effect of the electrolyte. In some examples, the surface tension of the electrolyte is 23.5 mN / m to 26 mN / m, and the contact angle between the electrolyte and the electrode is 25° to 30°.
[0083] In the examples above, the additives are not limited to perfluoropolyetheramine and polyethylene glycol dioleate, but may also include other additives.
[0084] The aforementioned battery cell preparation method involves multiple stages of electrolyte injection into the battery cell precursor. In the first stage, a negative pressure environment expels gas from the macroscopic pores of the electrode. Post-injection pressurization promotes electrolyte penetration into the small pores and deep pores of the electrode surface. In subsequent stages, a negative pressure environment expels air bubbles remaining in the electrode micropores, and post-injection pressurization further promotes electrolyte wetting of the electrode. After injection, many pores in the electrode remain unabsorbed by electrolyte. Rotating the battery cell at a relatively low speed of 10-14 rpm promotes electrolyte absorption in the larger pores. As the larger pores are filled, the electrolyte effectively wets the electrode. Increasing the rotation speed to 18-30 rpm further penetrates the smaller and deeper pores of the electrode, improving the rate and uniformity of electrolyte penetration. This battery cell preparation method effectively improves the wetting effect and injection efficiency of high-capacity batteries.
[0085] The above-mentioned method for preparing battery cells can improve the penetration effect of high-viscosity electrolyte in high-voltage solid electrode sheets, improve the problem of black spots on the electrode sheets caused by insufficient electrolyte wetting, and thus improve its electrical performance.
[0086] The above-mentioned method for preparing battery cells achieves deep wetting of electrolyte and electrode active materials. For high-capacity batteries, sufficient electrolyte wetting can effectively improve the utilization efficiency of active materials, ensure sufficient and continuous electrode reaction, and help high-capacity batteries achieve stable long-term energy storage output, such as 4-hour energy storage output or 8-hour energy storage output.
[0087] Furthermore, this application also provides a single battery cell. This single battery cell is obtained using the preparation method of any of the examples described above.
[0088] Furthermore, this application also provides a battery device. The battery device includes the aforementioned battery cell. The battery device includes one or more of the following: a battery module, a battery pack, and an energy storage battery.
[0089] Furthermore, this application also provides an electrical appliance. The electrical appliance includes the aforementioned battery device. The battery device is used to provide electrical energy in the electrical appliance.
[0090] Furthermore, this application also provides an energy storage device. The energy storage device includes the aforementioned battery device. The battery device is used to store electrical energy.
[0091] The following specific embodiments further illustrate this application. These specific embodiments are provided to better understand this application, but are not limited to them and do not constitute a limitation on the content or scope of protection of this application.
[0092] The following examples and comparative examples use the same battery cell semi-finished products in terms of structure and materials, all of which are large-capacity square-shell battery cell semi-finished products without liquid filling.
[0093] The positive electrode slurry coated on the positive electrode sheet includes: 97 parts of active material (lithium iron phosphate), 1 part of conductive agent (SP and CNT), 2 parts of binder (PVDF), and 90 parts of solvent (NMP). The negative electrode slurry coated on the negative electrode sheet includes: 97 parts of active material (graphite), 2 parts of binder (CMC and SBR), 1 part of conductive agent (SP), and 70 parts of solvent (water).
[0094] Example 1
[0095] The method for preparing a single battery cell provided in this embodiment includes the following steps:
[0096] Step 1: Prepare the electrolyte. The electrolyte consists of 28% lithium salt (LiPF6) by mass and 72% solvent (EC, DMC, and EMC mixed in a volume ratio of 1:1:1). The surface tension of the electrolyte is 38.2 mN / m, and the contact angle with the electrode is 52°.
[0097] Step 2: Place the semi-finished battery cell in a negative pressure environment of -80 kPa for venting. After maintaining this for 5 minutes, inject electrolyte into the semi-finished battery cell, filling it to 50% of its total volume. After electrolyte injection, place the semi-finished battery cell in a positive pressure environment of +50 kPa and maintain this for 3 minutes for electrolyte immersion.
[0098] Step 3: Place the semi-finished battery cell obtained in Step 2 under a negative pressure environment of -95 kPa for venting. After maintaining this environment for 100 seconds, inject the remaining electrolyte into the semi-finished battery cell. After electrolyte injection, place the semi-finished battery cell under a positive pressure environment of +80 kPa and maintain this environment for 50 seconds for electrolyte immersion treatment.
[0099] Step 4: Depressurize the semi-finished battery cell obtained in Step 3 to +0 kPa and hold for 5 seconds, then pressurize it to +80 kPa and hold for 50 seconds. Repeat the depressurization and pressurization processes multiple times until the fifth depressurization process is completed, thus completing the liquid injection process and obtaining the liquid-injected cell.
[0100] Step 5: The injected cell is divided into three sections and rotated at different speeds. The first section is rotated at 12 rpm for 50 seconds, the second section is rotated at 16 rpm for 90 seconds, and the third section is rotated at 25 rpm for 90 seconds to obtain the battery cell.
[0101] The pressure change diagram during the injection process in this embodiment is shown below. Figure 4 As shown, the rotational speed change during rotation processing is as follows:Figure 5 As shown.
[0102] Example 2
[0103] The method for preparing a single battery cell provided in this embodiment includes the following steps:
[0104] Step 1: Prepare the electrolyte. The electrolyte consists of 28% lithium salt (LiPF6) by mass and 72% solvent (EC, DMC, and EMC mixed in a volume ratio of 1:1:1). The surface tension of the electrolyte is 38.2 mN / m, and the contact angle with the electrode is 52°.
[0105] Step 2: Place the semi-finished battery cell in a negative pressure environment of -70 kPa for venting. After maintaining this for 5 minutes, inject electrolyte into the semi-finished battery cell, filling it to 50% of its total volume. After electrolyte injection, place the semi-finished battery cell in a positive pressure environment of +40 kPa and maintain this for 8 minutes for electrolyte immersion.
[0106] Step 3: Place the semi-finished battery cell obtained in Step 2 under a negative pressure environment of -80 kPa for venting. After maintaining this environment for 100 seconds, inject the remaining electrolyte into the semi-finished battery cell. After electrolyte injection, place the semi-finished battery cell under a positive pressure environment of +70 kPa and maintain this environment for 80 seconds for electrolyte immersion treatment.
[0107] Step 4: Depressurize the semi-finished battery cell obtained in Step 3 to +0 kPa and hold for 5 seconds, then pressurize it to +70 kPa and hold for 50 seconds. Repeat the depressurization and pressurization processes multiple times until the fifth depressurization process is completed, thus completing the liquid injection process and obtaining the liquid-injected cell.
[0108] Step 5: The injected cell is divided into three sections and rotated at different speeds. The first section is rotated at 10 rpm for 60 seconds, the second section is rotated at 15 rpm for 120 seconds, and the third section is rotated at 20 rpm for 120 seconds to obtain the battery cell.
[0109] Example 3
[0110] The method for preparing a single battery cell provided in this embodiment includes the following steps:
[0111] Step 1: Prepare the electrolyte. The electrolyte consists of 28% lithium salt (LiPF6) by mass and 72% solvent (EC, DMC, and EMC mixed in a volume ratio of 1:1:1). The surface tension of the electrolyte is 38.2 mN / m, and the contact angle with the electrode is 52°.
[0112] Step 2: Place the semi-finished battery cell in a negative pressure environment of -90 kPa for venting. After maintaining this for 5 minutes, inject electrolyte into the semi-finished battery cell, filling it to 80% of its total volume. After electrolyte injection, place the semi-finished battery cell in a positive pressure environment of +60 kPa and maintain this for 8 minutes for electrolyte immersion.
[0113] Step 3: Place the semi-finished battery cell obtained in Step 2 under a negative pressure environment of -100 kPa for venting. After maintaining this environment for 100 seconds, inject the remaining electrolyte into the semi-finished battery cell. After electrolyte injection, place the semi-finished battery cell under a positive pressure environment of +90 kPa and maintain this environment for 80 seconds for electrolyte wetting treatment.
[0114] Step 4: Depressurize the semi-finished battery cell obtained in Step 3 to +0 kPa and hold for 5 seconds, then pressurize it to +90 kPa and hold for 50 seconds. Repeat the depressurization and pressurization processes multiple times until the fifth depressurization process is completed, thus completing the liquid injection process and obtaining the liquid-injected cell.
[0115] Step 5: The injected cell is divided into three sections and rotated at different speeds. The first section is rotated at 14 rpm for 30 seconds, the second section is rotated at 18 rpm for 60 seconds, and the third section is rotated at 30 rpm for 60 seconds to obtain the battery cell.
[0116] Example 4
[0117] The difference between this embodiment and Embodiment 1 is only that, in step 1, the electrolyte comprises 28% lithium salt (LiPF6) by mass, 69.7% solvent (EC, DMC, and EMC mixed in a volume ratio of 1:1:1), 0.3% perfluoropolyetheramine by mass, and 2% polyethylene glycol dioleate by mass. The surface tension of the electrolyte is 24 mN / m, and the contact angle with the electrode is 30°.
[0118] Example 5
[0119] The difference between this embodiment and Embodiment 2 is only that, in step 1, the electrolyte comprises 28% lithium salt (LiPF6) by mass, 70% solvent (EC, DMC, and EMC mixed in a volume ratio of 1:1:1), 0.5% perfluoropolyetheramine by mass, and 1.5% polyethylene glycol dioleate by mass. The surface tension of the electrolyte is 24.5 mN / m, and the contact angle with the electrode is 28°.
[0120] Example 6
[0121] The difference between this embodiment and Embodiment 3 is only that, in step 1, the electrolyte comprises 28% lithium salt (LiPF6) by mass, 69.9% solvent (EC, DMC, and EMC mixed in a volume ratio of 1:1:1), 0.4% perfluoropolyetheramine by mass, and 1.7% polyethylene glycol dioleate by mass. The surface tension of the electrolyte is 23.5 mN / m, and the contact angle with the electrode is 25°.
[0122] Comparative Example 1
[0123] The method for preparing the battery cell proposed in this comparative example includes the following steps:
[0124] Step 1: Prepare the electrolyte. The electrolyte consists of 28% lithium salt (LiPF6) by mass and 72% solvent (EC, DMC, and EMC mixed in a volume ratio of 1:1:1). The surface tension of the electrolyte is 38.2 mN / m, and the contact angle with the electrode is 52°.
[0125] Step 2: Place the semi-finished battery cell in a negative pressure environment of -80 kPa for venting. After maintaining this for 5 minutes, inject all the electrolyte into the semi-finished battery cell. The electrolyte injection process is then complete, yielding the battery cell.
[0126] Comparative Example 2
[0127] The only difference between this comparative example and Example 1 is that step 5 was not performed.
[0128] The battery cells prepared in the above embodiments and comparative examples were subjected to performance tests, including initial efficiency (first coulombic efficiency), rate performance, and cycle performance. Initial efficiency is the ratio of discharge capacity to charge capacity during the first charge and discharge cycle, reflecting the energy loss during the charge and discharge process. Rate performance is the capacity retention rate under 1C charge and discharge conditions. Cycle performance is the energy retention rate after 500 cycles under 0.5C and 1C charge and discharge conditions. The performance test results are shown in Table 1.
[0129] Table 1 Performance test results of the battery cells prepared in each embodiment and comparative example
[0130]
[0131] As shown in Table 1, compared with Comparative Examples 1-2, the battery cells prepared in Examples 1-6 all showed improvements in initial efficiency, rate performance, and cycle performance. Specifically, Example 4 outperformed Example 1, Example 5 outperformed Example 2, and Example 6 outperformed Example 3. This is attributed to the combined use of the additives perfluoropolyetheramine and polyethylene glycol dioleate, which significantly reduced the surface tension of the electrolyte and the contact angle between the electrolyte and the electrode, thus improving the wetting effect of the electrolyte.
[0132] The battery cells prepared in Examples 1-6 and Comparative Examples 1-2 were disassembled to observe whether black spots appeared on the electrodes. The results are shown in Table 2.
[0133] Table 2. Black spots on the electrode sheets in the battery cells prepared in each embodiment and comparative example.
[0134]
[0135] No black spots appeared on the electrode in the battery cells prepared in Examples 1-6, while black spots appeared on the electrode in Comparative Examples 1-2. This shows that the battery cell preparation method of this application can effectively improve the wetting effect of electrolyte injection in large-capacity batteries and improve the problem of black spots on the electrode caused by insufficient electrolyte wetting.
[0136] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0137] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A method for preparing a single battery cell, characterized in that, Includes the following steps: The battery cell semi-finished product is injected with electrolyte in multiple stages to obtain injected cells. The process of each stage of electrolyte injection includes: first, placing the corresponding semi-finished product in a negative pressure environment for degassing, then injecting electrolyte into the degassed semi-finished product, and finally placing it in a positive pressure environment for electrolyte wetting. The injection unit is rotated at different speeds, including a first rotation at 10 rpm to 14 rpm and a second rotation at 18 rpm to 30 rpm, with the second rotation occurring after the first rotation.
2. The method for preparing a single battery cell as described in claim 1, characterized in that, During the venting process at each stage of the liquid injection process, the negative pressure environment pressure in the later stage is lower than that in the previous stage.
3. The method for preparing a single battery cell as described in claim 1, characterized in that, During the immersion treatment in each stage of the liquid injection process, the positive pressure environment pressure in the later stage is higher than that in the previous stage.
4. The method for preparing a battery cell according to any one of claims 1 to 3, characterized in that, The injection is performed in two stages.
5. The method for preparing a single battery cell as described in claim 4, characterized in that, During the first stage of liquid injection, the air pressure of the negative pressure environment is -70kPa to -90kPa, and the liquid is injected after maintaining this pressure for 5 to 10 minutes. During the second stage of liquid injection, the air pressure of the negative pressure environment is -80kPa to -100kPa, and is maintained for 80s to 160s before liquid injection.
6. The method for preparing a single battery cell as described in claim 4, characterized in that, The first stage involves injecting 50% to 80% of the total electrolyte volume, and the second stage involves injecting the remaining electrolyte.
7. The method for preparing a single battery cell as described in claim 4, characterized in that, During the first stage of injection, the pressure of the positive pressure environment is +40kPa to +60kPa and is maintained for more than 3 minutes. During the second stage of injection, the pressure of the positive pressure environment is +70kPa to +90kPa and is maintained for 30s to 80s.
8. The method for preparing a battery cell according to any one of claims 1-3 and 5-7, characterized in that, It also includes the step of repeatedly depressurizing and pressurizing the obtained semi-finished product after impregnation under positive pressure in the final stage.
9. The method for preparing a battery cell as described in claim 8, characterized in that, During the pressure relief process, the air pressure for each event is controlled independently to be +0 kPa to +5 kPa and maintained for 3 to 10 seconds. During the pressurization process, the air pressure is controlled independently at +70kPa to +90kPa and maintained for 30s to 80s.
10. The method for preparing a single battery cell as described in claim 8, characterized in that, Perform the pressure relief procedure at least five times.
11. The method for preparing a battery cell according to any one of claims 1-3, 5-7, and 9-10, characterized in that, The process of rotating the injection unit at different speeds is to perform segmented rotation at different speeds, with the speed of the later segment being higher than that of the earlier segment.
12. The method for preparing a single battery cell as described in claim 11, characterized in that, The rotation is divided into three segments with different speeds: the first segment rotates at 10 rpm to 14 rpm for 30 to 60 seconds, the second segment rotates at 14 rpm to 18 rpm for 60 to 120 seconds, and the third segment rotates at 18 rpm to 30 rpm for 60 to 120 seconds.
13. The method for preparing a battery cell according to any one of claims 1-3, 5-7, 9-10, and 12, characterized in that, The electrolyte comprises 5% to 38% lithium salt by mass, 60% to 90% solvent by mass, and 2% to 10% additives by mass.
14. The method for preparing a single battery cell as described in claim 13, characterized in that, The additives include perfluoropolyetheramine and polyethylene glycol dioleate, wherein the perfluoropolyetheramine has a mass fraction of 0.3% to 0.6% in the electrolyte and the polyethylene glycol dioleate has a mass fraction of 1% to 2% in the electrolyte.
15. A single battery cell, characterized in that, The battery cell is obtained by the preparation method of any one of claims 1 to 14.
16. A battery device, characterized in that, The battery device includes the battery cell of claim 15, and the battery device includes one or more of the following: battery module, battery pack, and energy storage battery.
17. An electrical appliance, characterized in that, Includes the battery device of claim 16, the battery device being used to provide electrical energy.
18. An energy storage device, characterized in that, The energy storage device includes the battery device of claim 16, the battery device being used to store electrical energy.