Electrode piece, electrode assembly and battery

Abstract

The utility model discloses a pole piece, an electrode assembly and a battery. The pole piece comprises a current collector and at least one electrode film, wherein the current collector is provided with two opposite side surfaces; at least one electrode film is attached to one side face of the current collector, and a groove formed in a rolling mode is formed in the side, facing the current collector, of at least one electrode film. By arranging the groove, a gap can be formed between the electrode film and the current collector, so that the infiltration area of electrolyte is increased, and the ion transmission efficiency is improved. Specifically, due to the existence of the groove, when the battery is charged, electrolyte is easier to permeate into the electrode membrane, so that electrochemical reaction is more sufficient, and the energy charging efficiency of the battery is improved. Therefore, the electrode plate is beneficial to electrolyte infiltration, and the ion conduction rate can be improved, so that the battery cell capacity can be increased by adopting the electrode assembly and the battery with the electrode plate, and efficient energy charging is realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field especially relates to a pole piece, electrode assembly and battery. BACKGROUND

[0002] In the existing lithium ion battery manufacturing technology, dry process as an important production mode, because of its unique advantages and attention. Compared with wet coating process, dry process does not use any organic solvent in the preparation process of electrode material, directly mixes active material, conductive agent and binder etc. and then is pressed into a film with certain thickness through rolling or other physical methods, and then is cut into the required size and assembled into the battery structure. This method not only simplifies the production process, reduces the cost, but also avoids the use of solvent, which can realize higher material utilization and better environmental performance in theory.

[0003] However, in practical application, the electrode prepared by dry method has some inherent challenges. First, since the electrode prepared by dry method is usually thicker than the electrode prepared by wet method, and does not undergo solvent plasticization, the compaction density of active material is higher in the rolling or physical compaction process, which helps to increase the active material content in unit volume, but also brings new problems. For example, the higher compaction density makes it more difficult for electrolyte to penetrate into the interior of the electrode, especially in the middle region of the electrode or the side close to the current collector, and the transmission speed of lithium ions will be significantly reduced. This phenomenon directly leads to the fact that part of the active material cannot be fully utilized in the actual charge and discharge process, thereby affecting the actual capacity performance of the whole battery, so that it cannot reach the theoretical maximum value. In addition, due to the tight internal structure of the electrode prepared by dry method, the poor wetting of electrolyte may also lead to uneven distribution of electrochemical reaction, increase the internal resistance of the battery, reduce the energy efficiency, and even may affect the safety of the battery in extreme cases. SUMMARY

[0004] The main purpose of the utility model is to provide a pole piece, electrode assembly and battery, the pole piece of the application is beneficial to electrolyte wetting, which can improve the ion conductivity, so that the electrode assembly of the pole piece of the application can increase the battery capacity and realize efficient energy storage.

[0005] To achieve the above purpose, some embodiments of the utility model provide a pole piece, electrode assembly and battery, the pole piece comprises:

[0006] The current collector has two opposite sides;

[0007] At least one electrode film is attached to one side of the current collector, and the side of the at least one electrode film facing the current collector is provided with a groove.

[0008] In some embodiments, the side of the electrode film facing the current collector is provided with a plurality of grooves, and each of the plurality of grooves is recessed towards the side away from the electrode film.

[0009] The depth of each of the plurality of grooves ranges from 5 μm to 20 μm.

[0010] In some embodiments, the plurality of grooves are arranged at intervals, and the spacing between the plurality of grooves ranges from 0.5 mm to 3.5 mm.

[0011] In some embodiments, the roughness of the current collector ranges from 0.15 Ra to 0.5 Ra.

[0012] In some embodiments, the side of the electrode film facing the current collector and the side of the electrode film away from the current collector are both provided with grooves.

[0013] In some embodiments, along the length direction of the electrode tab, the grooves on the side of the electrode film facing the current collector and the grooves on the side of the electrode film away from the current collector are alternately arranged.

[0014] In some embodiments, the groove has a bottom wall and a side wall surrounding the bottom wall, the side wall has oppositely arranged first and second wall surfaces, and the distance from the first wall surface to the second wall surface gradually decreases in the recessed direction of the groove.

[0015] In some embodiments, the groove is a tapered groove.

[0016] Embodiments of the second aspect of the application disclose an electrode assembly comprising a separator and an electrode tab according to any one of the preceding claims.

[0017] Embodiments of the third aspect of the application disclose a battery comprising an electrode assembly according to any one of the preceding claims.

[0018] According to the above embodiments, the application has the following beneficial effects:

[0019] The electrode tab of the application comprises a current collector, the current collector has two opposite side surfaces. At least one electrode film is attached to one of the side surfaces of the current collector, and the side of the at least one electrode film facing the current collector is provided with a roll-formed groove. By providing the groove, a gap can be formed between the electrode film and the current collector, thereby increasing the wetting area of the electrolyte and improving the ion transmission efficiency. Specifically, due to the presence of the groove, when the battery is charged, the electrolyte can more easily penetrate into the electrode film, so that the electrochemical reaction is more complete, thereby improving the charging efficiency of the battery.

[0020] Additional aspects and advantages of the application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below only constitute some of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained according to the structure shown in the drawings without creative labor.

[0022] Figure 1 The structure schematic diagram of the pole piece in an embodiment of the present application is shown in the figure.

[0023] Figure 2 The structure schematic diagram of the pole piece in an embodiment of the present application is shown in the figure. Figure 1 The structure schematic diagram of the pole piece in an embodiment of the present application is shown in the figure.

[0024] Figure 3 The structure schematic diagram of the pole piece in an embodiment of the present application is shown in the figure.

[0025] Explanation of the figure mark:

[0026] The current collector 100;

[0027] The electrode film 200;

[0028] The groove 300.

[0029] The realization, functional characteristics and advantages of the present application will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0031] It should be noted that if the present application embodiments involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement condition, etc. between the components in a certain posture, and if the certain posture changes, the directional indications also change accordingly.

[0032] In addition, if the description of "first", "second" and the like is involved in the embodiments of the present application, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can be explicitly or implicitly included at least one of the features. In addition, if "and / or", "and / or" or "and / or" appears in the whole text, it means that the three parallel schemes are included, for example, "A and / or B" includes A scheme, or B scheme, or A and B scheme. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the present application.

[0033] The following will be described with reference to Figures 1 to 3 The pole piece, the electrode assembly and the battery according to the embodiments of the present application.

[0034] Referring to Figure 1 and Figure 2 In some embodiments, the pole piece of the present application is made by dry process, including a current collector 100, the current collector 100 has opposite two side surfaces. At least one electrode film 200 is attached to one side surface of the current collector 100, and at least one of the electrode film 200 is provided with a roll-formed groove 300 on the side of the current collector 100. By setting the groove 300, a gap can be formed between the electrode film 200 and the current collector 100, thereby increasing the wetting area of the electrolyte and improving the ion transmission efficiency. Specifically, due to the existence of the groove 300, when the battery is charged, the electrolyte is more easily penetrated into the electrode film 200, so that the electrochemical reaction is more sufficient, thereby improving the charging efficiency of the battery.

[0035] It can be understood that in some embodiments, the groove 300 provided on the side of the electrode film 200 towards the current collector 100 can be formed by controlling the pressure distribution in the dry process. During the pressing process, by the specific design of the pressure distribution, the groove 300 with a certain depth can be formed on the surface of the electrode film 200. These grooves 300 not only increase the contact area of the electrolyte, but also help to improve the mechanical properties of the electrode film 200, prevent the electrode film 200 from cracking due to material expansion and contraction during repeated charging and discharging, thereby improving the overall performance and service life of the battery. In addition, the design of the groove 300 also helps to improve the density distribution uniformity of the electrode film 200, ensuring the consistency and stability of the electrochemical reaction.

[0036] In addition, the design of the grooves 300 needs to consider the impact of their depth on battery performance. Grooves 300 that are too shallow may not significantly improve the wettability of the electrolyte, while grooves 300 that are too deep can cause the electrode film 200 structure to be unstable, affecting the safety and cycle life of the battery. Therefore, the depth of the grooves 300 needs to be within a suitable range, and the depth of the grooves 300 in this application is between 5 pm and 20 pm. Such a design can not only ensure sufficient electrolyte contact area, but also will not affect the basic structural integrity of the electrode film 200.

[0037] Of course, the design of the grooves 300 in this application not only improves the charging efficiency in actual use, but also enables the electrode film 200 to better disperse the current when in contact with the current collector 100, reducing the risk of local overheating.

[0038] Referring to Figure 1 In some embodiments, the side of the electrode film 200 facing the current collector 100 is provided with a plurality of grooves 300, and the plurality of grooves 300 are recessed away from the side of the electrode film 200. The depth of the plurality of grooves 300 is in the range of 5 pm to 20 pm, for example, 5 pm, 10 pm, 15 pm, and 20 pm. The design of the plurality of grooves 300 can further increase the contact area of the electrolyte, so that more active materials participate in the electrochemical reaction, thereby effectively improving the charging efficiency of the battery. At the same time, the uniform distribution of the grooves 300 helps to ensure the uniformity of the electrolyte distribution inside the electrode film 200, reducing the phenomenon of local reaction imbalance and improving the overall stability and consistency of the battery.

[0039] It can be understood that in some embodiments, in order to realize the design of the plurality of grooves 300, the shape of the mold in the dry preparation process can be adjusted. By designing a mold with a specific shape, the plurality of uniformly distributed grooves 300 can be formed in the electrode film 200 during the pressing process. Moreover, the depth of these grooves 300 should be controlled between 5 pm and 20 pm to ensure that the structure stability of the electrode film 200 is not affected while effectively increasing the wettability area of the electrolyte. In addition, by adjusting the size and shape of the mold, precise control of the number and distribution of the grooves 300 can be achieved, thereby optimizing the physical structure inside the battery and improving its overall performance.

[0040] In addition, the presence of the plurality of grooves 300 not only increases the contact area of the electrolyte, but also helps to improve the thermal stability of the electrode film 200. The heat generated during the operation of the battery can be quickly dissipated through these grooves 300, preventing local overheating and causing the battery to fail. In addition, by precisely controlling the size and distribution of the grooves 300, the energy density and power density of the battery can be further optimized, making it more suitable for high energy density demand application scenarios.

[0041] It can be understood that in some embodiments, by changing the geometry of the grooves 300, such as from a simple straight groove 300 to a curved or mesh structure, the mechanical strength of the electrode film 200 can be further improved without increasing the amount of material used. In some embodiments, the groove 300 has a bottom wall and a side wall surrounding the bottom wall, the side wall has a first wall surface and a second wall surface arranged opposite to each other, and the distance from the first wall surface to the second wall surface gradually decreases in the direction of the recess of the groove 300, that is, the cross section of the groove 300 is trapezoidal; in some embodiments, the groove 300 is a tapered groove. These geometric changes help to prevent film cracking caused by uneven stress during battery charging and discharging, while also ensuring the long-term stability and safety of the battery. Through these improvements, the battery can withstand more cycles in actual use without failure.

[0042] Referring to Figure 2 In some embodiments, the electrode film 200 is attached to one side of the current collector 100, and the side of the electrode film 200 facing the current collector 100 and the side facing away from the current collector 100 are both provided with roll-formed grooves 300. By providing grooves 300 on both sides of the electrode film 200, the contact area between the electrode film 200 and the electrolyte can be significantly increased, thereby improving the electrochemical activity of the electrode film 200. Specifically, because the electrode film 200 has grooves 300 on both sides, the electrolyte can more fully infiltrate the electrode film 200, which not only helps to improve the charging and discharging efficiency of the battery, but also enhances the cycle stability of the battery. In addition, the presence of the grooves 300 also promotes uniform distribution of substances inside the electrode film 200, which is beneficial to improving the overall performance of the battery.

[0043] It can be understood that in some embodiments, the grooves 300 on both sides of the electrode film 200 can be achieved by adjusting the mold in the dry preparation process. During the pressing process, through a specially designed mold, grooves 300 can be formed on both sides of the electrode film 200. These grooves 300 help to improve the mechanical properties of the electrode film 200, preventing deformation or cracking of the electrode film 200 caused by repeated charging and discharging during battery use. In addition, the design of double-sided grooves 300 can further improve the uniformity of the density distribution of the electrode film 200, ensuring the consistency and stability of the electrochemical reaction. By controlling the depth of the grooves 300 within a certain range, the capacity and energy density of the battery can be effectively improved without affecting the basic structural integrity of the electrode film 200.

[0044] Referring to Figure 2 and Figure 3In some embodiments, along the length direction of the pole piece, the grooves 300 on the side of the electrode film 200 facing the current collector 100 and the grooves 300 on the side of the electrode film 200 facing away from the current collector 100 are alternately arranged. This alternating arrangement can further optimize the structure of the electrode film 200 and improve the performance of the battery. On the one hand, this design avoids the corresponding arrangement of two grooves 300, which can cause the electrode film 200 to be too thin and easily broken. On the other hand, the alternating grooves 300 can effectively improve the permeability and uniformity of the electrolyte, reduce the risk of local overheating and overcharging, and thus improve the cycle stability and safety of the battery.

[0045] Referring to Figure 2 and Figure 3 In some embodiments, the roughness of the current collector 100 is in the range of 0.15 Ra to 0.5 Ra, such as 0.15 Ra, 0.25 Ra, 0.35 Ra, 0.45 Ra, or 0.5 Ra. The roughness of the current collector 100 refers to the microscopic unevenness of the surface of the current collector 100, which can be measured by a surface roughness meter. A reasonable range of roughness helps to increase the contact area between the electrode film 200 and the current collector 100. This increased contact area not only improves the adhesion strength between the electrode film 200 and the current collector 100, but also increases the effective area of the electrochemical reaction, thereby improving the capacity and cycle stability of the battery.

[0046] Embodiments of the second aspect of the application propose an electrode assembly comprising a separator and the pole piece of any of the preceding embodiments. By combining the pole piece with grooves 300 and the separator to form an electrode assembly, the performance of the battery can be further optimized. Specifically, the grooves 300 on the pole piece not only increase the contact area between the electrode film 200 and the electrolyte, but also form a small space between the electrode film 200 and the separator, which helps to evenly distribute the electrolyte. When the battery is charging and discharging, the electrolyte can better penetrate into the electrode film 200, improving the efficiency of the electrochemical reaction. In addition, by selecting a suitable separator material, the safety and cycle life of the battery can be further enhanced.

[0047] It is understood that in some embodiments, the design of the electrode assembly takes into account the interaction between the electrode film 200 and the separator. The grooves 300 on the tab help to distribute the electrolyte evenly within the electrode film 200, while the choice of separator is also crucial. The ideal separator should have good insulating properties and sufficient mechanical strength to prevent short circuits from occurring. In addition, the separator also needs to have a certain porosity so that the electrolyte can pass through smoothly without causing excessive resistance. By properly matching the electrode film 200 and the separator, the electrode assembly formed can provide higher energy density and better safety. In addition, this design also helps to improve the thermal stability of the battery, preventing excessive temperature from being generated during high-current discharge, thereby extending the service life of the battery.

[0048] The tab of the present application is pressed by a tab pressing roller, which includes at least one roller having a circumferential wall surface arranged circumferentially around its own axis. A plurality of protrusions are provided on the circumferential wall surface, and the protrusions protrude towards the direction of the circumferential wall surface away from the axis of the roller. The protrusions are designed to apply a specific pressure pattern to the electrode film 200 during the pressing process, thereby forming corresponding grooves 300 on the electrode film 200. When the tab pressing roller is in operation, the protrusions will come into contact with the electrode film 200 and press it into forming grooves 300, which help to improve the charging efficiency of the battery. Specifically, the shape and distribution of the protrusions determine the shape and distribution of the grooves 300 on the final electrode film 200, thereby affecting the working performance of the battery.

[0049] It is understood that in some embodiments, the protrusions provided on the circumferential wall surface of the roller of the tab pressing roller can be in various forms, such as cylindrical, conical or other structures suitable for forming the desired shape of the grooves 300. The size and arrangement of the protrusions directly affect the effect of the grooves 300 on the electrode film 200. By designing the size, height and spacing of the protrusions, it can be ensured that the grooves 300 of a certain shape are formed on the electrode film 200, which not only helps to improve the charging efficiency of the battery, but also improves the mechanical properties of the electrode film 200. In addition, the arrangement of the protrusions can also help to adjust the density distribution of the electrode film 200, so that the battery is more uniform during charging and discharging, reducing the possibility of local overheating.

[0050] In some embodiments, the protrusions are configured as ribs, and the height of the ribs ranges from 5 μm to 20 μm, for example, the height of the ribs is 5 μm, 10 μm, 15 μm, or 20 μm. The design of the ribs makes the depth of the grooves 300 formed on the electrode film 200 moderate, neither too deep nor too shallow, ensuring that the electrode film 200 has sufficient space to accommodate the electrolyte while maintaining good structural stability, thereby improving the charging efficiency of the battery. Specifically, the height of the ribs determines the depth of the grooves 300 on the electrode film 200, and the groove depth of 5 μm to 20 μm can effectively increase the contact area between the electrode film 200 and the electrolyte, thereby improving the charging and discharging efficiency of the battery.

[0051] It can be understood that, in some embodiments, the height of the ribs is set to range from 5 μm to 20 μm to ensure that the grooves 300 on the electrode film 200 can significantly increase the contact area with the electrolyte, and the structural strength of the electrode film 200 will not decrease due to the excessive depth of the grooves 300. By precisely controlling the height of the ribs, the surface structure of the electrode film 200 can be optimized, the wettability of the electrolyte can be improved, and thus the overall performance of the battery can be improved. In addition, the appropriate depth of the grooves 300 also helps to improve the thermal management performance of the electrode film 200, reduce the heat generated during the operation of the battery, and improve the safety and reliability of long-term operation of the battery.

[0052] In some embodiments, a plurality of protrusions are arranged on the peripheral wall surface of the electrode tab pressing roller, and protrude away from the roller axis in the direction away from the peripheral wall surface. The protrusions are configured as ribs, and the plurality of ribs are arranged at intervals, and the spacing between the plurality of ribs ranges from 0.5 mm to 3.5 mm, for example, the spacing between the plurality of ribs is 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, or 3.5 mm. This design allows the ribs to press the electrode film 200 according to the predetermined spacing during the rolling process, forming regularly distributed grooves 300. The regularly distributed grooves 300 help to increase the contact area between the electrode film 200 and the current collector 100, thereby improving the charging efficiency and cycle life of the battery.

[0053] It can be understood that the spacing of the ribs is designed to ensure that the grooves 300 on the electrode film 200 are evenly distributed, avoiding the performance degradation of the battery due to uneven distribution of the grooves 300. The spacing between the ribs is set between 0.5mm and 3.5mm, which can make the distance between each groove 300 large enough to ensure the structural strength of the electrode film 200, while also allowing each groove 300 to effectively increase the surface area of the electrode film 200 and improve the degree of electrolyte infiltration. In addition, by controlling the spacing of the ribs, the density distribution of the electrode film 200 can also be adjusted to be more uniform, thereby improving the working efficiency and service life of the battery. At the same time, the design of the spacing also takes into account the heat effect generated during the charging and discharging process of the battery, and a reasonable spacing can help dissipate heat and prevent local temperature from being too high.

[0054] In some embodiments, the plurality of ribs are evenly spaced on the peripheral wall surface. This uniform distribution design allows the electrode film 200 to form uniformly distributed grooves 300 when it is rolled, which helps to improve the surface utilization of the electrode film 200 and allows the electrolyte to be more evenly distributed on the electrode film 200. The uniformly distributed grooves 300 can increase the contact area between the electrode film 200 and the electrolyte, thereby improving the charging efficiency of the battery. In addition, the uniformly distributed grooves 300 can also help maintain the structural stability of the electrode film 200 and prevent the electrode film 200 from breaking due to local stress concentration during battery use.

[0055] Of course, it can be understood that the uniform distribution of the ribs not only helps to form uniform grooves 300, but also improves the overall performance of the battery. By evenly distributing the ribs on the peripheral wall surface, it can be ensured that each groove 300 is formed uniformly, which avoids the electrode film 200 being too dense or sparse in some areas, thereby ensuring the consistency of the electrochemical reaction inside the battery. In addition, the uniformly distributed ribs also help to improve the mechanical properties of the electrode film 200 and prevent damage to the electrode film 200 during battery manufacturing and use. The uniform distribution design can also help optimize the distribution of substances on the electrode film 200 and improve the cycle performance and energy density of the battery. At the same time, the uniform spacing is also beneficial for the thermal management of the battery, preventing local overheating and improving the safety of the battery.

[0056] In some embodiments, the protrusions are configured as conical stakes with a diameter ranging from 0.5mm to 3.5mm. By designing the protrusions in the form of conical stakes, specific groove 300 shapes can be formed on the electrode film 200. These grooves 300 not only help to increase the specific surface area of the electrode film 200, thereby improving the charging efficiency of the battery, but also help to improve the mechanical properties of the electrode film 200. Specifically, the design of the conical stakes causes the grooves 300 formed on the electrode film 200 to have a gradually changing cross-sectional shape with a large opening cross-section and a small bottom cross-section, which helps to improve the wettability of the electrolyte and can promote uniform distribution of substances inside the electrode film 200, thereby improving the overall performance of the battery.

[0057] It can be understood that, in some embodiments, the protrusions are configured as conical stakes with a diameter ranging from 0.5mm to 3.5mm, for example 0.5mm, 1.0mm, 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm, in order to ensure that the grooves 300 formed on the electrode film 200 can effectively increase the contact area with the electrolyte without damaging the basic structure of the electrode film 200. The design of the conical stakes causes the grooves 300 formed on the electrode film 200 to have a large opening and a narrow bottom, which helps to improve the mechanical strength of the electrode film 200 and prevent deformation or rupture during the charging and discharging process of the battery. In addition, the design of the conical stakes also helps to optimize the density distribution of the electrode film 200, making the battery more uniform during charging and discharging and reducing the possibility of local overheating. By adjusting the size of the conical stakes, the performance of the battery can be further optimized, such as increasing the energy density, prolonging the cycle life, etc.

[0058] In some embodiments, the electrode sheet pressing roller includes two said roller wheels, the axes of the two said roller wheels are parallel, and the positions of the two said roller wheels correspond to each other so that the electrode film 200 passes between the two said roller wheels. The minimum distance L between the peripheral wall surfaces of the two said roller wheels and the thickness h of the electrode film 200 satisfy the relationship: h+2μm≤L≤h+4μm, for example L is h+2μm, h+3μm, h+4μm. This design allows the electrode film 200 to pass between the two roller wheels during the rolling process, while ensuring that the electrode film 200 is subjected to appropriate pressure to form the required grooves 300. The setting of the minimum distance L between the two roller wheels ensures that the electrode film 200 is not damaged by excessive pressure when being rolled, while ensuring that the depth of the grooves 300 is moderate, neither too shallow to effectively increase the contact area of the electrolyte, nor too deep to cause the structural strength of the electrode film 200 to decrease.

[0059] In some embodiments, the peripheral wall surface of each of the two rollers is provided with grooves 300. By providing grooves 300 on the peripheral wall surface of the two rollers, uniformly distributed grooves 300 can be formed on the electrode film 200, thereby improving the charging efficiency of the electrode film 200. Specifically, when the electrode film 200 passes between the two rollers, the grooves 300 on the peripheral wall surface of the rollers will press corresponding grooves 300 on the electrode film 200, which helps to increase the surface area of the electrode film 200, so that the electrolyte can better infiltrate the electrode film 200, thereby improving the charging and discharging efficiency of the battery.

[0060] It can be understood that, in some embodiments, the design of providing grooves 300 on the peripheral wall surface of the two rollers can ensure that the grooves 300 on the electrode film 200 are uniformly distributed. By controlling the shape, size and distribution of the grooves 300, the performance of the electrode film 200 can be further optimized. Specifically, the grooves 300 on the two rollers can ensure that the upper and lower surfaces of the electrode film 200 form consistent grooves 300 when passing through, which helps to improve the structural stability and mechanical strength of the electrode film 200. In addition, the uniform distribution of the grooves 300 also helps to improve the density distribution of the electrode film 200, so that the battery is more uniform during charging and discharging, reducing the possibility of local overheating. By adjusting the size and distribution of the grooves 300, the performance of the battery can be further optimized, such as increasing the energy density, prolonging the cycle life, etc.

[0061] In some embodiments, a laser process is used to process the electrode sheet of the present application. Specifically, a laser that is suitable for processing the surface precision of the electrode film 200 is used to process the surface of the electrode film 200.

[0062] It can be understood that, according to the three aspects of the embodiments of the present application, the present application also protects a process method for preparing the electrode sheet and the electrode assembly of the present application. Specifically, the preparation method is as follows:

[0063] 1. Mixing of raw materials: mix the active material and the conductive additive uniformly according to a certain proportion. Dry method, mechanical mixing and other methods can be used for mixing to ensure the uniformity and consistency of the raw materials.

[0064] 2. Crushing: crush the mixed raw materials to make the particle size suitable for the needs of the electrode material. The crushing methods include ball milling, shock grinding, etc.

[0065] 3. Dry powder mixing: form the final powder mixture composed of active material, binder and conductive additive.

[0066] 4. Forming from powder to thin coating: extruding and calendering the powder mixture to form a continuous self-supporting dry coating electrode film 200,

[0067] 5. The electrode film 200 is then processed by rolling or laser technology to form V-shaped grooves 300, conical dots, and other irregularly shaped grooves 300 on the side or both sides of the dry electrode film 200 where the fluid is attached.

[0068] In this process, the roll forming process uses the irregularly shaped rollers of any of the aforementioned embodiments. Specifically, a single-sided roller has raised stripes (the stripe length spans the roller surface) arranged at equal intervals on the roller surface. The equal intervals can be set to 1mm, 2mm, 3mm, etc., and the height of the raised stripes can be different heights such as 10μm, 15μm, 20μm, etc. Alternatively, conical dots can be used, with diameters of 1mm, 2mm, 3mm, etc., and heights of 10μm, 15μm, 20μm, etc. In some embodiments, double-sided rollers are used, with grooves 300 or recesses added to both sides, i.e., both sides of the rollers are irregularly shaped rollers. The distance between the two rollers is the thickness of the 200 electrode films + 2μm~4μm to prevent the electrode films from breaking if the distance is too small, or the grooves 300 or recesses from being too large. This depth is half the depth of the single-sided groove stripes.

[0069] Regarding the laser process, specifically, a laser suitable for the surface precision of the electrode film 200 is used to perform surface treatment processing on the electrode film 200.

[0070] 6. Press the processed electrode film 200 with the current collector 100. The thin electrode layer and the current collector 100 are pressed together by continuous dry rolling to form the battery electrode sheet.

[0071] 7. Battery cell manufacturing is carried out according to traditional procedures.

[0072] A third aspect of this application provides a battery including the electrode assembly of any of the foregoing embodiments. The electrode assembly used in this application includes a current collector 100 with two opposing sides. At least one electrode film 200 is attached to one side of the current collector 100, and at least one of the electrode films 200 has a roll-formed groove 300 on the side facing the current collector 100. By providing the groove 300, a gap can be formed between the electrode film 200 and the current collector 100, thereby increasing the wetting area of ​​the electrolyte and improving ion transport efficiency. Specifically, due to the presence of the groove 300, when the battery is charging, the electrolyte can more easily penetrate into the interior of the electrode film 200, making the electrochemical reaction more complete, thereby improving the battery's charging efficiency.

[0073] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the inventive concept of this utility model and the contents of this utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this utility model.

Claims

1. An electrode sheet, characterized in that, include: The current collector has two opposing sides; At least one electrode film is attached to one side of the current collector, and at least one of the electrode films has a groove on the side facing the current collector; The groove has a bottom wall and side walls surrounding the bottom wall. The side walls have a first wall surface and a second wall surface that are disposed opposite to each other. Along the concave direction of the groove, the distance between the first wall surface and the second wall surface gradually decreases.

2. The electrode sheet according to claim 1, characterized in that, The electrode membrane has a plurality of grooves on the side facing the current collector, and the plurality of grooves are recessed on the side away from the electrode membrane; The depth range of each of the grooves is 5μm to 20μm.

3. The electrode sheet according to claim 1, characterized in that, The plurality of grooves are arranged at intervals, and the spacing between the plurality of grooves ranges from 0.5mm to 3.5mm.

4. The electrode sheet according to claim 1, characterized in that, The roughness of the current collector is in the range of 0.15Ra to 0.5Ra.

5. The electrode sheet according to claim 1, characterized in that, The electrode film has grooves on both the side facing the current collector and the side away from the current collector.

6. The electrode sheet according to claim 5, characterized in that, Along the length of the electrode sheet, the grooves on the side of the electrode film facing the current collector and the grooves on the side away from the current collector are alternately distributed.

7. The electrode sheet according to claim 1, characterized in that, The groove is a conical groove.

8. An electrode assembly, characterized in that, Includes a diaphragm and an electrode as described in any one of claims 1-7.

9. A battery, characterized in that, Includes the electrode assembly as described in claim 8.

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