Manufacturing method of battery cell pole piece, battery cell pole piece and battery cell
By forming a cracked layer on the surface of the coating and optimizing its structure, the problem of poor wettability of the coating was solved, the wetting speed of the electrolyte and the electrochemical reaction rate were improved, and the time and energy consumption of the battery cell manufacturing were reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUNGROW POWER SUPPLY CO LTD
- Filing Date
- 2024-11-05
- Publication Date
- 2026-05-08
AI Technical Summary
In existing technologies, a thicker coating layer leads to a decrease in the wetting speed and wettability of the electrolyte in the coating layer, which increases the time and energy consumption costs of the battery cell manufacturing process.
By forming a first crack layer on the surface of the coating layer and forming a second crack layer by rolling, the structure of the coating layer is optimized to improve the wetting speed and wettability of the electrolyte and reduce the diffusion path.
It increases the contact area between the electrolyte and the coating, shortens the cell manufacturing process time, reduces energy consumption costs, and improves the electrochemical reaction rate.
Smart Images
Figure CN122000270A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery cell electrode technology, and more specifically, to a method for manufacturing a battery cell electrode and a battery cell electrode. Background Technology
[0002] A battery cell includes battery cell electrodes, which include a current collector and a coating layer on the surface of the current collector. The coating layer is a positive or negative active material that reacts electrochemically with the electrolyte to complete the storage and release of electrical energy.
[0003] In related technologies, to shorten the ion diffusion path within the coating layer, it is necessary to improve the wettability of the coating layer in the electrolyte. However, due to the thickness of the coating layer, the wetting speed and wettability of the electrolyte in the coating layer deteriorate, thereby increasing the time and energy consumption costs of the cell manufacturing process. Summary of the Invention
[0004] This application provides a method for manufacturing a battery cell electrode, a battery cell electrode, and a battery cell.
[0005] The method for manufacturing a battery cell electrode sheet provided in this application includes: providing a current collector; coating a slurry on the surface of the current collector to form a coating layer; baking the coating layer to form a first crack layer corresponding to the coating layer; and rolling the first crack layer to form a second crack layer corresponding to the first crack layer, thereby obtaining the battery cell electrode sheet.
[0006] In the method for manufacturing a battery cell electrode provided in this application embodiment, during electrode coating, a baking process is set to form a corresponding first crack layer on the coating layer of the battery cell electrode, and the electrode with the first crack layer is rolled to obtain a battery cell electrode with a second crack layer.
[0007] The second cracked layer increases the contact area between the electrolyte and the coating layer, while also reducing the diffusion path of the electrolyte within the coating layer. This facilitates the rapid penetration of the electrolyte through the coating layer into the cell electrode, and also promotes the rapid diffusion of active materials into the cell electrode, thereby increasing the electrochemical reaction rate of the cell.
[0008] In some embodiments, baking the coating layer to form a first cracked layer corresponding to the coating layer includes: adjusting the ambient temperature of the coating layer to a first preset temperature to bake the coating layer and form the first cracked layer; adjusting the ambient temperature of the first cracked layer to a second preset temperature to cool the first cracked layer, wherein the second preset temperature is lower than the first preset temperature; adjusting the ambient temperature of the coating layer to a third preset temperature to dry the coating layer, wherein the third preset temperature is higher than the second preset temperature; and adjusting the ambient temperature of the coating layer to a fourth preset temperature to cool the dried coating layer, wherein the fourth preset temperature is lower than the third preset temperature.
[0009] In the method for manufacturing the battery electrode sheet provided in this application, during the baking of the coating layer, it is necessary not only to dry the coating layer to remove the solvent and form a solid coating layer, but also to form a first crack layer on the surface of the coating layer. When moisture is present in the coating layer, the first crack layer is more likely to form due to the volume difference between the liquid and solid materials. However, when the coating layer is solid, the first crack layer is not easy to form. Therefore, the first crack layer can be formed on the surface of the coating layer first, and then the moisture in the coating layer can be removed. The ambient temperature of the coating layer can typically be set to "high temperature-low temperature-high temperature-low temperature".
[0010] In some embodiments, the first preset temperature is 105℃~115℃, the second preset temperature is 75℃~85℃, the third preset temperature is 95℃~105℃, and the fourth preset temperature is 75℃~85℃.
[0011] In some embodiments, rolling the first cracked layer to form a second cracked layer corresponding to the first cracked layer, thereby obtaining the cell electrode sheet, includes: rolling the first cracked layer using a hot rolling process.
[0012] In the hot rolling process, setting the temperature allows for adjusting the crack width of the second crack layer according to requirements.
[0013] In some embodiments, the crack width of the second cracked layer is a1, where 0.1 mm < a1 ≤ 0.5 mm.
[0014] If the width of the cracks in the second crack layer is too small, it hinders the rapid infiltration of the electrolyte into the cell electrode, impedes the rapid diffusion of active materials into the cell electrode, and reduces the electrochemical reaction rate of the cell. When the crack width of the second crack layer is set to be greater than 0.1 mm, the rate at which the electrolyte infiltrates into the cell electrode through the cracks increases significantly, and the electrochemical reaction rate of the cell increases significantly.
[0015] If the crack width of the second crack layer is too large, active materials (such as lithium metal) can easily precipitate out from the cracks, affecting the lifespan of the battery cell electrode. Setting the crack width of the second crack layer to less than or equal to 0.5 mm can effectively prevent the precipitation of active materials (such as lithium metal) from the cracks caused by an excessively large crack width.
[0016] In some embodiments, the crack width of the first cracked layer is a2, where a1 < a2 ≤ 1 mm.
[0017] If the crack width of the first crack layer is too large, the migration of the coating layer on the surface of the battery cell electrode will be difficult to adjust, and there is a risk of coating layer peeling off. When the crack width of the first crack layer is set to less than or equal to 1 mm, the risk of coating layer peeling off due to the excessive crack width of the first crack layer can be effectively avoided.
[0018] In some embodiments, the crack depth of the second cracked layer is 30% to 70% of the coating thickness.
[0019] If the crack depth of the second crack layer is set too small, it will hinder the rapid infiltration of the electrolyte into the cell electrode through the cracks, impede the rapid diffusion of active materials into the cell electrode, and negatively impact the electrochemical reaction rate of the cell. When the crack depth of the second crack layer is set to be greater than 30% of the coating thickness, the rate at which the electrolyte infiltrates into the cell electrode through the cracks increases significantly, and the electrochemical reaction rate of the cell increases significantly.
[0020] If the crack depth of the second crack layer is set too large, fluctuations in the manufacturing process may cause the coating layer to completely crack, disrupting its continuity and preventing current from flowing smoothly through the battery electrode, thus significantly reducing the conductivity of the battery electrode. Setting the crack depth of the second crack layer to less than 70% of the coating layer thickness can effectively avoid the risk of complete cracking of the coating layer due to excessive crack depth.
[0021] In some embodiments, applying a slurry to the surface of the current collector to form the coating layer includes: applying the slurry to the upper surface of the current collector using a first adhesive to form the upper surface of the coating layer; and applying the slurry to the lower surface of the current collector using a second adhesive to form the lower surface of the coating layer, wherein the adhesive strength of the second adhesive is higher than that of the first adhesive.
[0022] In this way, a battery cell electrode sheet with cracks on the upper surface of the coating layer and almost no cracks on the lower surface of the coating layer can be obtained.
[0023] In some embodiments, applying a slurry to the surface of the current collector to form the coating layer includes: applying a first slurry to the upper surface of the current collector to form the upper surface of the coating layer; and applying a second slurry to the lower surface of the current collector to form the lower surface of the coating layer, wherein the particle size of the second slurry is larger than that of the first slurry.
[0024] In this way, a battery cell electrode sheet with cracks on the upper surface of the coating layer and almost no cracks on the lower surface of the coating layer can be obtained.
[0025] This application provides a method for manufacturing a battery cell electrode, a battery cell electrode, and a battery cell. The method for manufacturing the battery cell electrode includes: providing a current collector; coating a slurry on the surface of the current collector to form a coating layer; baking the coating layer to form a first crack layer corresponding to the coating layer; and rolling the first crack layer to form a second crack layer corresponding to the first crack layer, thereby obtaining the battery cell electrode.
[0026] In the method for manufacturing a battery electrode sheet provided in this application, during electrode coating, a baking process is used to form a first crack layer in the coating layer of the battery electrode sheet. The electrode sheet with the first crack layer is then rolled to obtain a battery electrode sheet with a second crack layer. The second crack layer increases the contact area between the electrolyte and the coating layer, while also reducing the diffusion path of the electrolyte within the coating layer. This facilitates the rapid penetration of the electrolyte through the coating layer into the interior of the battery electrode sheet, and also facilitates the rapid diffusion of active materials into the interior of the battery electrode sheet, thereby increasing the electrochemical reaction rate of the battery cell.
[0027] Additional aspects and advantages of embodiments of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of embodiments of this application. Attached Figure Description
[0028] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, wherein:
[0029] Figure 1 This is a schematic flowchart of the method for manufacturing the battery cell electrode sheet according to an embodiment of this application;
[0030] Figure 2 This is a schematic diagram of the cell electrode sheets of some embodiments of this application;
[0031] Figure 3 This is a schematic flowchart of a method for manufacturing battery cell electrode sheets according to certain embodiments of this application;
[0032] Figure 4 This is a schematic diagram of the cell electrode sheet of some embodiments of this application.
[0033] Explanation of key component symbols:
[0034] The battery cell electrode 100, current collector 10, coating layer 20, first crack layer 21, and second crack layer 22. Detailed Implementation
[0035] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are optional and are only used to explain the embodiments of this application, and should not be construed as limiting the embodiments of this application.
[0036] A battery cell includes battery cell electrodes, which include a current collector and a coating layer on the surface of the current collector. The coating layer is a positive or negative active material that reacts electrochemically with the electrolyte to complete the storage and release of electrical energy.
[0037] In related technologies, to shorten the ion diffusion path within the coating layer, it is necessary to improve the wettability of the coating layer in the electrolyte. However, due to the thickness of the coating layer, the wetting speed and wettability of the electrolyte in the coating layer deteriorate, thereby increasing the time and energy consumption costs of the cell manufacturing process.
[0038] To address the aforementioned technical problems, this application provides a method for manufacturing battery cell electrode sheets (e.g., ...). Figure 1 as well as Figure 3 (as shown) and cell electrodes (such as Figure 2 as well as Figure 4 As shown in the figure, this can improve the wetting speed and wettability of the electrolyte in the coating layer, thereby reducing the time and energy consumption costs of the cell manufacturing process.
[0039] Reference Figure 1 The method for manufacturing the cell electrode 100 provided in this application includes:
[0040] Step 01: Provide current collector 10;
[0041] Step 02: Apply slurry to the surface of current collector 10 to form coating layer 20;
[0042] Step 03: Bake the coating layer 20 to form a first cracked layer 21 corresponding to the coating layer 20;
[0043] Step 04: Roll the first crack layer 21 to form a second crack layer 22 corresponding to the first crack layer 21, thereby obtaining the cell electrode 100.
[0044] The cell electrode 100 of this application embodiment is manufactured by the cell electrode 100 manufacturing method provided in this application embodiment, referring to... Figure 2 The cell electrode 100 includes a current collector 10, a coating layer 20, and a second crack layer 22. The coating layer 20 is formed on the surface of the current collector 10, and the second crack layer 22 is formed on the surface of the coating layer 20.
[0045] In the method for manufacturing the battery electrode 100 provided in the embodiments of this application, during the electrode coating process, a baking process is set to form a corresponding first crack layer 21 on the coating layer 20 of the battery electrode 100, and the first crack layer 21 is rolled to obtain a battery electrode 100 having a second crack layer 22.
[0046] The second cracked layer 22 increases the contact area between the electrolyte and the coating layer 20, and also reduces the diffusion path of the electrolyte within the coating layer 20. This facilitates the rapid penetration of the electrolyte through the coating layer 20 into the cell electrode 100, and also facilitates the rapid diffusion of active materials into the cell electrode 100, thereby increasing the electrochemical reaction rate of the cell.
[0047] Specifically, in step 01, the current collector 10 is the conductive component in the cell electrode 100, connecting the electrode material and the external circuit. The conductivity of the current collector 10 affects the internal resistance of the cell; the better the conductivity of the current collector 10, the lower the internal resistance of the cell, and the higher the charging and discharging efficiency of the cell. The material selected for the current collector 10 can include metal materials (including copper, aluminum, nickel, etc.) and other metal materials with good conductivity. Aluminum current collector 10 can be used for positive electrode current collector 10 (e.g., lithium cobalt oxide positive electrode), and copper current collector 10 can be used for positive electrode current collector 10 (e.g., graphite negative electrode).
[0048] In step 02, the slurry may consist of an active material (such as lithium cobalt oxide for the positive electrode or graphite for the negative electrode), a conductive agent (such as carbon black or a conductive polymer), a binder (such as a polymer binder), and a solvent (such as water or an organic solvent). The above materials are mixed in a certain proportion using a high-shear mixer to ensure uniformity and stability of the slurry. A coating machine (such as a doctor blade coater, spray coater, or roller coater) can be used to coat the slurry onto the current collector 10. The coating methods of the coating machine may include doctor blade coating (slurry is uniformly coated by a doctor blade, suitable for large-area coating), spray coating (slurry is sprayed through a nozzle, suitable for precise control of the coating amount), and roller coating (slurry is coated by a roller, suitable for mass production). The slurry is coated on the surface of the current collector 10, forming a corresponding coating layer 20.
[0049] In step 03, the coating layer 20 can be baked at a high temperature. During the high-temperature baking process, the moisture inside the coating layer 20 is heated and evaporated, causing the volume of the coating layer 20 to shrink. The surface of the coating layer 20 will correspondingly generate tension. The increased surface tension of the coating layer 20 causes the coating layer 20 to crack, forming the first cracked layer 21. High-temperature baking also causes a temperature difference between the inside and the surface of the coating layer 20. As the temperature difference between the inside and the surface of the coating layer 20 increases, the surface of the coating layer 20 will also generate surface stress, causing the coating layer 20 to crack and forming the first cracked layer 21.
[0050] Furthermore, since the coating layer 20 is composed of multiple materials, during the baking process, each material in the coating layer 20 generates different internal stresses due to thermal shrinkage. Uneven shrinkage can also cause the coating layer 20 to crack, forming a first cracked layer 21. In some materials, baking the coating layer 20 may cause some materials to change from a liquid to a solid state or from a solid to a liquid state, resulting in corresponding volume changes in different materials, causing the coating layer 20 to crack and form the first cracked layer 21.
[0051] In step 04, after the coating and baking processes of the cell electrode 100 are completed, a rolling process is performed. The rolling process treats the cell electrode under high pressure to improve its performance. For example, the rolling process can increase the volumetric density of the cell electrode, thereby increasing the energy density of the battery. The rolling process increases the contact area between the electrode and the material, reducing interfacial resistance and thus improving conductivity. A rolling press (such as a hot press or a cold press) can be used to perform the rolling process, and the rolling parameters (time, pressure, and temperature) can be set on the rolling press according to actual needs.
[0052] Reference Figure 2 The finished product obtained in step 03 is rolled to form a second cracked layer 22 corresponding to the first cracked layer 21, thereby obtaining the battery cell electrode 100. The gap width of the second cracked layer 22 obtained after rolling is smaller than the gap width of the first cracked layer 21.
[0053] The battery cell electrode 100 provided in this embodiment has a second cracked layer 22, which is formed on the surface of the coating layer 20. When the electrolyte enters the interior of the coating layer 20, the second cracked layer 22 increases the contact area between the electrolyte and the coating layer 20, and also reduces the diffusion path of the electrolyte within the coating layer 20. This facilitates the rapid penetration of the electrolyte through the coating layer 20 into the interior of the battery cell electrode 100, and also facilitates the rapid diffusion of active materials into the interior of the battery cell electrode 100, thereby increasing the electrochemical reaction rate of the battery cell.
[0054] Thus, the battery cell electrode manufacturing method and battery cell electrode provided in this application embodiment can improve the wetting speed and wettability of the electrolyte in the coating layer 20, thereby reducing the time and energy consumption cost of the battery cell manufacturing process.
[0055] Reference Figure 3 In some embodiments, step 03: baking the coating layer 20 to form a first cracked layer 21 corresponding to the coating layer 20 includes:
[0056] Step 031: Adjust the ambient temperature of the coating layer 20 to the first preset temperature to bake the coating layer 20 and form the first cracked layer 21;
[0057] Step 032: Adjust the ambient temperature of the first cracked layer 21 to a second preset temperature to cool the first cracked layer 21. The second preset temperature is lower than the first preset temperature.
[0058] Step 033: Adjust the ambient temperature of the coating layer 20 to the third preset temperature to dry the coating layer 20. The third preset temperature is higher than the second preset temperature.
[0059] Step 034: Adjust the ambient temperature of the coating layer 20 to the fourth preset temperature to cool the dried coating layer 20. The fourth preset temperature is lower than the third preset temperature.
[0060] Specifically, in related technologies, after the slurry is applied to the surface of the current collector 10, the coating layer 20 needs to be dried to remove the solvent and form a solid coating layer 20. The drying method can be natural drying, hot air drying, vacuum drying, or baking drying.
[0061] If baking and drying are used, the drying temperature and time need to be set according to the composition and thickness of the slurry. In this case, the coating layer 20 can be heated first and then cooled. The ambient temperature of the coating layer 20 can usually be set to "low temperature-high temperature-low temperature".
[0062] In the method for manufacturing the battery cell electrode 100 provided in this application embodiment, during the baking of the coating layer 20, it is necessary not only to dry the coating layer 20 to remove solvent and form a solid coating layer 20, but also to form a first crack layer 21 on the surface of the coating layer 20. When moisture is present in the coating layer 20, the first crack layer 21 is more likely to form due to the inconsistency in volume between the liquid and solid materials. However, when the coating layer 20 is solid, the first crack layer 21 is not easy to form. Therefore, the first crack layer 21 can be formed on the surface of the coating layer 20 first, and then the moisture in the coating layer 20 can be removed. The ambient temperature of the coating layer 20 can typically be set to "high temperature-low temperature-high temperature-low temperature".
[0063] In step 03, the ambient temperatures of the coating layer 20 and the first cracked layer 21 are basically the same. An oven can be used for baking. By setting the temperature of the oven, the ambient temperatures of the coating layer 20 and the first cracked layer 21 can be set; that is, by setting the temperature of the oven, a first preset temperature, a second preset temperature, a third preset temperature, and a fourth preset temperature can be set.
[0064] In step 031, the temperature of the baking oven can be increased to raise the ambient temperature of the coating layer 20 to a first preset temperature, so as to bake the coating layer 20 and form the first cracked layer 21.
[0065] In step 32, the temperature of the oven can be lowered so that the ambient temperature of the first cracked layer 21 drops to the second preset temperature, thereby cooling the first cracked layer 21.
[0066] In step 033, the temperature of the baking oven can be increased so that the ambient temperature of the coating layer 20 rises to the third preset temperature to dry the coating layer 20.
[0067] In step 034, the temperature of the baking oven can be lowered so that the ambient temperature of the coating layer 20 drops to the fourth preset temperature, thereby cooling the dried coating layer 20.
[0068] In some embodiments, the first preset temperature is 105℃~115℃, the second preset temperature is 75℃~85℃, the third preset temperature is 95℃~105℃, and the fourth preset temperature is 75℃~85℃.
[0069] Specifically, in some embodiments, the first preset temperature is 110°C, the second preset temperature is 80°C, the third preset temperature is 100°C, and the fourth preset temperature is 80°C.
[0070] The first preset temperature can be set to a relatively large value to ensure that the coating layer 20 forms the corresponding first crack layer 21 in step 031.
[0071] In some embodiments, step 04: rolling the first cracked layer 21 to form a second cracked layer 22 corresponding to the first cracked layer 21, thereby obtaining the cell electrode 100, includes: rolling the first cracked layer 21 using a hot rolling process.
[0072] Specifically, hot rolling involves applying pressure to a material while it is heated to promote its flowability and shaping. Cold rolling, on the other hand, applies pressure at or below room temperature, relying primarily on the material's mechanical properties for shaping.
[0073] Compared to cold rolling, hot rolling involves higher temperatures. The temperature of hot rolling can be adjusted, and by increasing the temperature, the viscosity of the rolled material can be reduced, promoting flow and thus improving the forming effect.
[0074] The crack width of the second cracked layer 22 can be set by adjusting the temperature of the hot rolling process. The higher the temperature of the hot rolling process, the better the fluidity of the coating layer 20 and the first cracked layer 21 during the rolling process, resulting in a smaller crack width in the second cracked layer 22.
[0075] In some embodiments, the crack width of the second cracked layer 22 is a1, where 0.1 mm < a1 ≤ 0.5 mm.
[0076] Specifically, if the width of the crack in the second crack layer 22 is too small, it will not be conducive to the electrolyte quickly penetrating into the cell electrode 100 through the crack in the second crack layer 22, nor will it be conducive to the rapid diffusion of active materials into the cell electrode 100, and thus will not be conducive to improving the electrochemical reaction rate of the cell.
[0077] When the crack width of the second crack layer 22 is set to be greater than 0.1 mm, the rate at which the electrolyte penetrates into the cell electrode 100 through the crack of the second crack layer 22 increases significantly, and the electrochemical reaction rate of the cell increases significantly.
[0078] If the crack width of the second crack layer 22 is too large, active materials (such as lithium metal) are easily precipitated from the gaps in the second crack layer 22, affecting the service life of the battery cell electrode.
[0079] When the crack width of the second crack layer 22 is set to be less than or equal to 0.5 mm, it can effectively prevent (e.g., lithium metal) from precipitating from the cracks of the second crack layer 22 due to excessive crack width.
[0080] In some embodiments, the crack width of the first cracked layer 21 is a2, where a1 < a2 ≤ 1 mm.
[0081] Specifically, the first cracked layer 21 is rolled to obtain the second cracked layer 22, so the crack width of the second cracked layer 22 is lower than that of the first cracked layer. If the crack width of the first cracked layer 21 is too large, the migration of the coating layer 20 on the surface of the cell electrode 100 is not easily adjusted, and there is a risk of the coating layer 20 falling off.
[0082] When the crack width of the first crack layer 21 is set to be less than or equal to 1 mm, the risk of coating layer 20 falling off due to excessive crack width of the first crack layer 21 can be effectively avoided.
[0083] In some embodiments, the crack depth of the second cracked layer 22 is 30% to 70% of the thickness of the coating layer 20.
[0084] Specifically, if the crack depth of the second crack layer 22 is set too small, it will not be conducive to the electrolyte quickly penetrating into the cell electrode 100 through the cracks of the second crack layer 22, nor will it be conducive to the rapid diffusion of active materials into the cell electrode 100, and thus will not be conducive to improving the electrochemical reaction rate of the cell.
[0085] When the crack depth of the second crack layer 22 is set to be greater than 30% of the thickness of the coating layer 20, the rate at which the electrolyte penetrates into the cell electrode 100 through the cracks of the second crack layer 22 increases significantly, and the electrochemical reaction rate of the cell increases significantly.
[0086] If the crack depth of the second crack layer 22 is set too large, the coating layer 20 may become completely cracked due to fluctuations in the manufacturing process, which would disrupt the continuity of the coating layer 20 and prevent the current from passing smoothly through the cell electrode 100, resulting in a significant reduction in the conductivity of the cell electrode 100.
[0087] When the crack depth of the second crack layer 22 is set to be less than 70% of the thickness of the coating layer 20, the risk of the coating layer 20 being completely cracked due to the excessive crack depth of the second crack layer 22 can be effectively avoided.
[0088] In some embodiments, step 02: applying slurry to the surface of the current collector 10 to form a coating layer 20 includes: applying slurry to the upper surface of the current collector 10 using a first adhesive to form the upper surface of the coating layer 20; and applying slurry to the lower surface of the current collector 10 using a second adhesive to form the lower surface of the coating layer 20, wherein the adhesive strength of the second adhesive is higher than that of the first adhesive.
[0089] In step 02, the adhesive can be made of materials such as polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), or styrene-butadiene rubber (SBR). In some embodiments, the second adhesive can be a high-viscosity SBR, and the first adhesive can be a conventional SBR.
[0090] The adhesive can adjust the bonding strength between the slurry and the current collector 10, that is, the bonding strength of the formed coating layer 20. Since the bonding strength of the second adhesive is higher than that of the first adhesive, the bonding strength of the upper surface of the coating layer 20 is lower than that of the lower surface of the coating layer 20.
[0091] In step 03, during the high-temperature baking process, because the bonding strength of the upper surface of the coating layer 20 is lower than that of the lower surface of the coating layer 20, the upper surface of the coating layer 20 is more prone to deformation than the lower surface of the coating layer 20. Furthermore, the various materials on the upper surface of the coating layer 20 are more susceptible to different internal stresses due to thermal shrinkage, leading to cracking and the formation of a first cracked layer 21. Therefore, by setting corresponding operating parameters, it can be ensured that the upper surface of the coating layer 20 forms the corresponding first cracked layer 21 while the lower surface of the coating layer 20 remains almost crack-free.
[0092] Reference Figure 4 The formation of a corresponding first crack layer 21 on the upper surface of the coating layer 20 ensures that the upper surface of the formed cell electrode has a corresponding second crack layer 22. The second crack layer 22 increases the contact area between the electrolyte and the coating layer 20, and also reduces the diffusion path of the electrolyte within the coating layer 20. This facilitates the rapid penetration of the electrolyte through the coating layer 20 into the cell electrode 100, and also facilitates the rapid diffusion of active materials into the cell electrode 100, thereby increasing the electrochemical reaction rate of the cell.
[0093] The lower surface of the coating layer 20 is almost free of cracks, which can ensure that the lower surface of the formed cell electrode is almost free of cracks, reduce the degree of cracking of the coating layer 20, and prevent the coating layer 20 from cracking completely.
[0094] In some embodiments, step 02: applying a slurry to the surface of the current collector 10 to form a coating layer 20 includes:
[0095] A first slurry is applied to the upper surface of the current collector 10 to form the upper surface of the coating layer 20; and a second slurry is applied to the lower surface of the current collector 10 to form the lower surface of the coating layer 20, wherein the particle size of the second slurry is higher than that of the first slurry.
[0096] In step 03, during the high-temperature baking process, because the particle size of the second slurry is larger than that of the first slurry, the particle size of the upper surface material of the coating layer 20 is smaller than that of the lower surface material. Due to the smaller particle size of the upper surface material, the lower surface material of the coating layer 20 has lower fluidity and higher surface tension. The upper surface of the coating layer 20 is more prone to deformation than the lower surface, and the various materials on the upper surface of the coating layer 20 are more likely to generate different internal stresses due to thermal shrinkage, leading to cracking and the formation of the first crack layer 21. Therefore, by setting the corresponding operating parameters, it can be ensured that the upper surface of the coating layer 20 forms the corresponding first crack layer 21 while the lower surface of the coating layer 20 hardly cracks.
[0097] Reference Figure 4The formation of a corresponding first crack layer 21 on the upper surface of the coating layer 20 ensures that the upper surface of the formed cell electrode has a corresponding second crack layer 22. The second crack layer 22 increases the contact area between the electrolyte and the coating layer 20, and also reduces the diffusion path of the electrolyte within the coating layer 20. This facilitates the rapid penetration of the electrolyte through the coating layer 20 into the cell electrode 100, and also facilitates the rapid diffusion of active materials into the cell electrode 100, thereby increasing the electrochemical reaction rate of the cell.
[0098] The lower surface of the coating layer 20 is almost free of cracks, which can ensure that the lower surface of the formed cell electrode is almost free of cracks, reduce the degree of cracking of the coating layer 20, and prevent the coating layer 20 from cracking completely.
[0099] This application also provides a battery cell, which includes the battery cell electrode 100 of the above embodiments.
[0100] In the battery cell provided in this embodiment, a second crack layer 22 is provided on the surface of the coating layer 20 of the battery cell electrode 100. The second crack layer 22 increases the contact area between the electrolyte and the coating layer 20, and also reduces the diffusion path of the electrolyte within the coating layer 20. This facilitates the rapid penetration of the electrolyte through the coating layer 20 into the interior of the battery cell electrode 100, and also facilitates the rapid diffusion of active materials into the interior of the battery cell electrode 100, thereby increasing the electrochemical reaction rate of the battery cell.
[0101] The battery cell provided in this application also includes other beneficial effects of the battery cell electrode provided in this application, which will not be described in detail here.
[0102] In the description of this specification, the references to terms such as "some embodiments," "in one example," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0103] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the function involved, as will be understood by those skilled in the art to which embodiments of this application pertain.
[0104] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are optional and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.
Claims
1. A method for manufacturing a battery cell electrode sheet, characterized in that, include: Provide current collectors; A slurry is applied to the surface of the current collector to form a coating layer; The coating layer is baked to form a first cracked layer corresponding to the coating layer; The first cracked layer is rolled to form a second cracked layer corresponding to the first cracked layer, thereby obtaining the battery cell electrode sheet.
2. The manufacturing method according to claim 1, characterized in that, The baking of the coating layer to form a first cracked layer corresponding to the coating layer includes: The ambient temperature of the coating layer is adjusted to a first preset temperature to bake the coating layer and form the first cracked layer; Adjust the ambient temperature of the first cracked layer to a second preset temperature to cool the first cracked layer, wherein the second preset temperature is lower than the first preset temperature; The ambient temperature of the coating layer is adjusted to a third preset temperature to dry the coating layer, wherein the third preset temperature is higher than the second preset temperature; The ambient temperature of the coating layer is adjusted to a fourth preset temperature to cool the dried coating layer. The fourth preset temperature is lower than the third preset temperature.
3. The manufacturing method according to claim 2, characterized in that, The first preset temperature is 105℃~115℃, the second preset temperature is 75℃~85℃, the third preset temperature is 95℃~105℃, and the fourth preset temperature is 75℃~85℃.
4. The manufacturing method according to claim 1, characterized in that, The rolling of the first cracked layer to form a second cracked layer corresponding to the first cracked layer, thereby obtaining the battery cell electrode sheet, includes: The first cracked layer was rolled using a hot rolling process.
5. The manufacturing method according to claim 1, characterized in that, The crack width of the second cracked layer is a1, 0.1mm < a1 ≤ 0.5mm.
6. The manufacturing method according to claim 5, characterized in that, The crack width of the first cracked layer is a2, where a1 < a2 ≤ 1 mm.
7. The manufacturing method according to claim 1, characterized in that, The crack depth of the second cracked layer is 30% to 70% of the thickness of the coating layer.
8. The manufacturing method according to claim 1, characterized in that, The coating slurry is applied to the surface of the current collector to form the coating layer, comprising: A first adhesive is applied to the upper surface of the current collector to form the upper surface of the coating layer; and A second adhesive is applied to the lower surface of the current collector to form the lower surface of the coating layer. The adhesive strength of the second adhesive is higher than that of the first adhesive.
9. The manufacturing method according to claim 1, characterized in that, Applying a slurry to the surface of the current collector to form the coating layer includes: A first slurry is applied to the upper surface of the current collector to form the upper surface of the coating layer; and A second slurry is applied to the lower surface of the current collector to form the lower surface of the coating layer, wherein the particle size of the second slurry is larger than that of the first slurry.
10. A battery cell electrode, characterized in that, The battery cell electrode includes: current collector; A coating layer is formed on the surface of the current collector; A second cracked layer is formed on the surface of the coating layer.
11. The cell electrode according to claim 10, characterized in that, The gap of the second cracked layer is a1, 0.1mm < a1 ≤ 0.5mm.
12. The cell electrode sheet according to claim 10, characterized in that, The depth of the second cracked layer is 30% to 70% of the thickness of the coating layer.
13. A battery cell, characterized in that, The battery cell includes the battery cell electrode as described in any one of claims 10-12.