An electrode plate, a preparation method thereof, a battery, and an electric device

Abstract

This invention discloses an electrode sheet, its preparation method, a battery, and an electrical device. The electrode sheet includes a current collector and an active material layer disposed on its surface. The active material layer includes a central region and first to fourth corner regions arranged sequentially along its circumference. First to fourth liquid-conducting and venting grooves are provided on the active material layer. One end of each of the first to fourth liquid-conducting and venting grooves converges and connects in the central region, and the other end extends to the first to fourth corner regions respectively, collectively forming an "X"-shaped or near-"X"-shaped liquid-conducting and venting channel penetrating the center and each corner region. This structure can simultaneously promote the rapid convergence and lateral diffusion of electrolyte from the corners to the center, eliminate wetting blind spots, shorten the overall wetting time, and provide a low-resistance escape path for gas generated during circulation from the center to the edge, alleviating gas accumulation, reducing internal resistance and the risk of side reactions. It can also improve the battery's posture adaptability and cycle life, and enhance the battery's capacity utilization, rate performance, and safety.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to an electrode sheet and its preparation method, a battery, and an electrical device. Background Technology

[0002] With the rapid development of the new energy industry, lithium-ion batteries are widely used in power batteries, energy storage systems, and other fields due to their advantages such as high energy density and long cycle life. Among the many battery structures, stacked cells have become an important development direction for battery products due to their higher space utilization and energy density.

[0003] However, during the production and recycling of laminated battery cells, the core technical challenges of insufficient electrolyte wetting and difficulty in venting internal gases remain constant. After lamination, the electrodes are affected by the encapsulation pressure and the volume changes caused by the expansion / contraction of the active material during charging and discharging. The pressure in the central region of the electrode is significantly higher than that in the edge region, forming a "central high-pressure zone." Under this structure, the electrolyte needs to slowly permeate from the edge of the electrode to the center, while the gases (such as H2 and CO2) generated inside the cell (especially in the central region) during charging and discharging cycles need to escape from the center to the edge. The two create a strong "wetting-venting countercurrent effect" inside the electrode.

[0004] This counterbalancing effect makes it difficult for the electrolyte to fully wet the central area of ​​the electrode, forming a "dry zone." Simultaneously, the inability to expel gases in time leads to their accumulation in the central area, further hindering electrolyte penetration. As the number of cycles increases, these problems accumulate and worsen, and in the later stages of cell cycling, "X"-shaped or "dog bone"-shaped bright spots of failure easily appear in the central area of ​​the electrode. These bright spots are essentially areas of active material failure caused by electrolyte deficiency, leading to a sharp increase in cell internal resistance, a significant decrease in rate performance, and rapid capacity decay. In severe cases, they can even cause cell bulging and an increased risk of thermal runaway, greatly limiting the performance improvement and lifespan extension of stacked cells. Therefore, there is an urgent need to develop an electrode structure that can solve these problems. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one objective of the present invention is to provide an electrode.

[0006] A second objective of this invention is to provide a method for preparing an electrode sheet.

[0007] A third objective of this invention is to provide a battery.

[0008] The fourth objective of this invention is to provide an electrical device.

[0009] In a first aspect, the present invention provides an electrode comprising a current collector and an active material layer disposed on at least one side surface of the current collector. The active material layer has a central region and a first corner region, a second corner region, a third corner region, and a fourth corner region arranged sequentially along the circumference of the central region. The first corner region and the third corner region are disposed opposite each other, and the second corner region and the fourth corner region are disposed opposite each other. The active material layer has a first liquid-guiding and venting groove, a second liquid-guiding and venting groove, a third liquid-guiding and venting groove, and a fourth liquid-guiding and venting groove. One end of the first liquid-guiding and venting groove, the second liquid-guiding and venting groove, the third liquid-guiding and venting groove, and the fourth liquid-guiding and venting groove converge and communicate at the central region, and the other end extends to the first corner region, the second corner region, the third corner region, and the fourth corner region, respectively.

[0010] The electrode sheet according to the embodiments of the present invention has at least the following beneficial effects: This electrode features a first, second, third, and fourth liquid-conducting venting channel on the active material layer. One end of each channel converges and connects to the central region of the active material layer, while the other end extends to the first, second, third (opposite to the first), and fourth (opposite to the second) corner regions arranged sequentially along the circumference of the central region. This forms a liquid-conducting venting channel penetrating the central region and its four circumferential corner regions, creating an "X"-shaped or near-"X"-shaped full-area diffusion hub. This structure allows the electrolyte to rapidly converge from the four corner regions towards the center along the liquid-conducting venting channels, and then diffuse laterally to the surrounding active material areas via capillary action. This completely eliminates the central "wetting blind zone" in traditional edge-penetration modes, reducing initial capacity loss due to insufficient wetting, thereby improving the cell's capacity utilization rate. Furthermore, it non-linearly shortens the entire wetting time, achieving efficient and rapid full-area wetting of the electrolyte and improving production efficiency. On the other hand, the various liquid-conducting venting channels can construct a synergistic and efficient venting path. Specifically, the "X"-shaped or near-"X"-shaped liquid-conducting venting channels formed by these channels can simultaneously provide a direct, low-resistance escape path or a "shortcut" for gases produced during cell cycling. Gases can be rapidly guided and diffused from the high-voltage central region to the electrode edge along the channels, effectively alleviating gas accumulation in the central region. This fundamentally alleviates the "wetting-venting counteracting effect," reduces the peak gas pressure in the central region, reduces problems such as increased internal resistance and expansion caused by internal gas accumulation, and reduces the risk of interfacial side reactions and active layer peeling caused by gas retention, thus helping to maintain stable electrochemical performance during cell cycling. Therefore, by setting the above-mentioned liquid-conducting venting channels on the active material layer, the spatial conflict between electrolyte wetting and gas venting can be fundamentally alleviated, while simultaneously achieving efficient and uniform electrolyte wetting and rapid and smooth gas venting.

[0011] The above-mentioned electrodes can be applied to batteries. By setting the above-mentioned liquid guiding and venting grooves on the active material layer, the electrodes have a significant anti-gravity advantage, giving the battery excellent posture adaptability. Regardless of whether the battery is placed upright, on its side, or in any other posture, in the "X"-shaped or near-"X"-shaped liquid guiding and venting channel structure constructed by the above-mentioned liquid guiding and venting grooves, at least one channel can generally form effective contact with the electrolyte surface and play a liquid guiding role. The electrolyte can flow bidirectionally through gravity and capillary action, thereby improving wetting efficiency and overcoming the problem of the sudden drop in liquid guiding efficiency of traditional parallel or vertical channels under certain postures, greatly improving the reliability of the battery in different application scenarios.

[0012] Furthermore, by incorporating the aforementioned liquid-conducting and venting grooves on the active material layer, the simultaneous optimization of electrolyte wetting and venting fundamentally alleviates the core conflict between electrolyte wetting and gas venting. This ensures that the active material is fully and uniformly utilized, significantly reducing the cell's internal resistance and improving rate performance and low-temperature discharge capability. More importantly, this structure can fundamentally suppress the generation of "X"-shaped or "dog bone" shaped failure bright spots in the later stages of cycling, thereby greatly extending the cell's cycle life and improving its safety and reliability.

[0013] The openings of each liquid-guiding and venting groove on the active material layer are specifically located on the surface of the active material layer facing away from the current collector. In some embodiments, each liquid-guiding and venting groove is a strip-shaped groove; further, in some embodiments, each liquid-guiding and venting groove is a straight groove.

[0014] According to some embodiments of the present invention, there is a gap between the end of the first liquid-guiding and venting groove located in the first corner region and the edge of the active material layer; that is, the end of the first liquid-guiding and venting groove located in the first corner region does not penetrate the edge of the active material layer. In some embodiments, the length of the active material layer is a, the width is b, and the diagonal length c of the active material layer is... The distance (i.e. minimum distance) between the end of the first liquid-guiding and venting groove located in the first corner region and the edge of the active material layer is 2.5%×c~5%×c.

[0015] According to some embodiments of the present invention, there is a gap between the end of the second liquid-guiding venting groove located in the second corner region and the edge of the active material layer. In some embodiments, the gap between the end of the second liquid-guiding venting groove located in the second corner region and the edge of the active material layer is 2.5%×c to 5%×c.

[0016] According to some embodiments of the present invention, there is a gap between the end of the third liquid-guiding venting groove located in the third corner region and the edge of the active material layer. In some embodiments, the gap between the end of the third liquid-guiding venting groove located in the third corner region and the edge of the active material layer is 2.5%×c to 5%×c.

[0017] According to some embodiments of the present invention, there is a gap between the end of the fourth liquid-guiding venting groove located in the fourth corner region and the edge of the active material layer. In some embodiments, the gap between the end of the fourth liquid-guiding venting groove located in the fourth corner region and the edge of the active material layer is 2.5%×c to 5%×c.

[0018] According to some embodiments of the present invention, there is a gap between the end of each liquid-guiding and venting groove located in the corresponding corner region and the edge of the active material layer. Further, the gap between the end of each liquid-guiding and venting groove located in the corresponding corner region and the edge of the active material layer is 2.5%×c to 5%×c.

[0019] If the aforementioned liquid-conducting venting grooves directly penetrate the edge of the active material layer, it will, on the one hand, reduce the structural strength of the electrode and increase the breakage rate. This is because the bonding strength between the active material layer and the current collector is lower at the edge than in the center. If the liquid-conducting venting grooves extend to the edge of the active material layer, it's equivalent to creating a "crack" at the electrode edge. During the stacking process, the cut of the liquid-conducting venting groove at the edge will become a stress concentration point, making the electrode prone to tearing along the direction of the groove when bent. Furthermore, during the cutting process, burrs and powder are easily generated at the end of the liquid-conducting venting grooves, leading to an increased rate of active material layer shedding. On the other hand, it will increase the risk of short circuits in the battery cell. The burrs and powder generated by the liquid-conducting venting grooves extending to the edge will mix into the battery cell, becoming a "micro-short circuit hazard point." Simultaneously, edge damage will expose the current collector. During stacking, the exposed current collector may come into contact with the current collector of adjacent electrodes, causing an internal short circuit. Especially during battery charge-discharge cycles, the expansion and contraction of the electrode will exacerbate edge damage, and the short circuit risk increases exponentially with the number of cycles. Furthermore, the fact that the liquid-conducting venting groove penetrates the edge of the active material layer can easily lead to electrolyte leakage and encapsulation failure. This is because the edge of the electrode is a critical sealing area for cell encapsulation. If the liquid-conducting venting groove penetrates the edge, it will form tiny pores on the encapsulation surface. During the charging and discharging process of the cell, changes in internal pressure will push the electrolyte to leak along the pores, which will not only cause electrolyte loss and battery capacity decay, but also corrode the encapsulation structure, causing safety problems such as cell bulging and leakage.

[0020] In response, since the core function of the aforementioned liquid-conducting venting channel is to construct a "rapid electrolyte wetting path" and a "efficient gas discharge path," this function can be achieved without the liquid-conducting venting channel directly penetrating the edge of the active material layer. It can effectively connect with the electrolyte storage area at the edge of the electrode and the venting space of the casing by being close to the edge (leaving a small safety distance). Based on this, by designing a gap between the end of the liquid-conducting venting channel located in the corner area and the edge of the active material layer, thus preventing it from penetrating the edge of the active material layer, it helps to ensure the structural strength of the electrode, reduce the electrode breakage rate and the risk of cell short circuits, and also reduce the risk of electrolyte leakage and encapsulation failure.

[0021] According to some embodiments of the present invention, the active material layer has a first diagonal and a second diagonal that intersect, the first diagonal connecting the diagonal between the first corner region and the third corner region, and the second diagonal connecting the diagonal between the second corner region and the fourth corner region, the first diagonal and the second diagonal intersecting at the central region. That is, the diagonal line connecting the first corner region and the third corner region opposite it on the active material layer forms the first diagonal, the diagonal line connecting the second corner region and the fourth corner region opposite it forms the second diagonal, and the first and second diagonals intersect at the central region. Further, the electrode satisfies at least one of the following conditions: Condition 1: The absolute value of the angle between the extension direction of the first liquid guiding and venting groove and the first diagonal is 0°~15°; Condition 2: The absolute value of the angle between the extension direction of the third liquid guiding and venting groove and the first diagonal is 0°~15°; Condition 3: The absolute value of the angle between the extension direction of the second liquid guiding and venting groove and the second diagonal is 0°~15°; Condition 4: The absolute value of the angle between the extension direction of the fourth liquid guiding and venting groove and the second diagonal is 0°~15°.

[0022] For example, the absolute value of the angle between the extension direction of each of the above liquid guiding and venting channels and its corresponding diagonal can be, but is not limited to, 0°, 2°, 3°, 5°, 6°, 8°, 10°, 12°, 13°, or 15°, or fall within the range of any two of the above values. The extension direction of the liquid guiding and venting channel can be based on its centerline; that is, the angle between the extension direction of the liquid guiding and venting channel and its corresponding diagonal can be understood as the angle between the extension direction of the centerline of the liquid guiding and venting channel and its corresponding diagonal.

[0023] Furthermore, if the above-mentioned liquid guiding and venting channels are straight liquid guiding and venting channels, the angle between the extending direction of the liquid guiding and venting channel and the corresponding diagonal is the angle between the liquid guiding and venting channel and the corresponding diagonal. Moreover, in some embodiments, each liquid guiding and venting channel is a straight liquid guiding and venting channel, and the absolute value of the angle between each liquid guiding and venting channel and the corresponding diagonal is 0°~15°.

[0024] According to some embodiments of the present invention, the angles between the first liquid-guiding venting channel and the third liquid-guiding venting channel and the first diagonal are both 0°; the angles between the second liquid-guiding venting channel and the fourth liquid-guiding venting channel and the second diagonal are also both 0°. That is, the first liquid-guiding venting channel and the third liquid-guiding venting channel are arranged along the first diagonal direction, and the second liquid-guiding venting channel and the fourth liquid-guiding venting channel are arranged along the second diagonal direction.

[0025] Further, in some embodiments, one end of the first liquid-guiding venting channel located in the central region is connected to one end of the third liquid-guiding venting channel located in the central region, and the connection position is located at the intersection of the first diagonal and the second diagonal. The first liquid-guiding venting channel and the third liquid-guiding venting channel are arranged along the first diagonal direction. Similarly, one end of the second liquid-guiding venting channel located in the central region is connected to one end of the fourth liquid-guiding venting channel located in the central region, and the connection position is located at the intersection of the first diagonal and the second diagonal. The second liquid-guiding venting channel and the fourth liquid-guiding venting channel are arranged along the second diagonal direction. This can also be understood as the active material layer having two liquid-guiding venting channels arranged in an "X" shape, intersecting along the diagonals of the active material layer. In some embodiments, the first liquid-guiding venting channel and the third liquid-guiding venting channel are symmetrically arranged along the intersection of the first diagonal and the second diagonal; the second liquid-guiding venting channel and the fourth liquid-guiding venting channel are symmetrically arranged along the intersection of the first diagonal and the second diagonal.

[0026] The diagonal area of ​​a battery cell (especially a square laminated cell) is usually the most difficult place for electrolyte to wet and where gas is most likely to accumulate. If the liquid-conducting venting channel only passes through the central area but does not extend to the corner area of ​​the electrode, the electrolyte can only diffuse from the center to the surrounding areas, and the four corners of the electrode or active material layer are still prone to wettability blind spots, and the gas is also difficult to be discharged to the outside quickly. In addition, if the liquid-conducting venting channel only passes through the central area but does not extend along the diagonal to the corner area of ​​the electrode, the length and coverage of the liquid-conducting venting channel designed in this way are limited, and the efficiency of the lateral diffusion of the electrolyte will be lower than that of the diagonal channel, and the liquid-conducting venting function cannot be fully utilized.

[0027] In some embodiments, the liquid guiding and venting channels are designed as an "X" shape, intersecting diagonally. This structural design creates a high-speed main channel directly reaching the traditional "wetting blind zone" and "venting dead zone" by connecting the four farthest corners of the active material layer (or electrode) to the center via the shortest path. This directly breaks through the "diagonal wetting bottleneck" of the electrode. Compared to arranging the liquid guiding and venting channels in other directions, this can more fully and efficiently guide the electrolyte to diffuse from the edge to the center, while quickly venting the gas in the diagonal area. Thus, through the simplest and most efficient structural layout, the two key and contradictory processes of electrolyte wetting and gas venting are precisely and synchronously optimized, which can effectively alleviate the "wetting-venting conflict" and simultaneously achieve efficient and rapid global diffusion of electrolyte and efficient low-pressure gas conduction. Furthermore, due to its symmetry and multidirectionality, it can ensure that the battery has at least one channel that can effectively utilize gravity for flow under any usage posture, further improving wettability, rate performance and cycle life. At the same time, it can specifically suppress the "X" or "dog bone" shaped bright spot problem caused by local drying and side reaction accumulation in the later stages of cycling.

[0028] According to some embodiments of the present invention, the width W of at least one of the first liquid guiding and venting groove, the second liquid guiding and venting groove, the third liquid guiding and venting groove, and the fourth liquid guiding and venting groove satisfies: 0.05 mm ≤ W ≤ 1 mm. For example, W may be, but is not limited to, 0.05 mm, 0.08 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.17 mm, 0.2 mm, 0.23 mm, 0.25 mm, 0.26 mm, 0.28 mm, 0.3 mm, 0.35 mm, 0.37 mm, 0.4 mm, 0.43 mm, 0.45 mm, 0.5 mm, 0.6 mm, 0.62 mm, 0.65 mm, 0.68 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.83 mm, 0.85 mm, 0.9 mm, 0.95 mm, or 1 mm, or fall within the range of any two of the above values. In some embodiments, the width W of each liquid guiding and venting groove satisfies: 0.05mm≤W≤1mm.

[0029] According to some embodiments of the present invention, the length of the active material layer is a, the width is b, and the diagonal length c of the active material layer is... The length L of at least one of the first liquid guiding and venting channel, the second liquid guiding and venting channel, the third liquid guiding and venting channel, and the fourth liquid guiding and venting channel satisfies: 90%×c / 2≤L≤95%×c / 2. In some embodiments, the length L of each of the above liquid guiding and venting channels satisfies: 90%×c / 2≤L≤95%×c / 2.

[0030] In some embodiments, one end of the first liquid-guiding venting channel and the third liquid-guiding venting channel are connected at the intersection of the first diagonal and the second diagonal of the active material layer, and the first liquid-guiding venting channel and the third liquid-guiding venting channel are arranged along the first diagonal direction. The total length L1 of the first liquid-guiding venting channel and the third liquid-guiding venting channel satisfies: 90%×c≤L1≤95%×c. One end of the second liquid-guiding venting channel and the fourth liquid-guiding venting channel are also connected at the intersection of the first diagonal and the second diagonal, and the second liquid-guiding venting channel and the fourth liquid-guiding venting channel are arranged along the second diagonal direction. The total length L2 of the second liquid-guiding venting channel and the fourth liquid-guiding venting channel satisfies: 90%×c≤L2≤95%×c. This can also be understood as the active material layer having two liquid-guiding venting channels arranged in an "X" shape, intersecting along the diagonal of the active material layer, and the length of both channels being 90%~95% of the diagonal length of the active material layer.

[0031] In some embodiments, the first liquid-guiding venting groove, the second liquid-guiding venting groove, the third liquid-guiding venting groove, and the fourth liquid-guiding venting groove are all arranged along the diagonal direction of the active material layer, and the length L of each liquid-guiding venting groove satisfies: 90%×c / 2≤L≤95%×c / 2.

[0032] According to some embodiments of the present invention, the single-sided thickness of the active material layer is H, and the depth h of at least one of the first liquid-guiding venting groove, the second liquid-guiding venting groove, the third liquid-guiding venting groove, and the fourth liquid-guiding venting groove satisfies: 1 / 5 H < h < 1 / 2 H. In some embodiments, the depth h of each liquid-guiding venting groove satisfies: 1 / 5 H < h < 1 / 2 H.

[0033] In some embodiments, the width W of each liquid guiding and venting groove is controlled to be in the range of 0.05mm to 1mm, the length L is in the range of (90% to 95%) × c / 2, and the height h is in the range of (1 / 5 to 1 / 2) × H.

[0034] The precise control over the width, length, and depth of the liquid guiding and venting channels facilitates an optimal balance between function and structure. Specifically, limiting the width of the channels within the specified range ensures sufficient capillary force for efficient electrolyte guidance while avoiding excessive use of active material area that could sacrifice battery energy density. Controlling the length of the channels allows them to extend sufficiently into most of the active material layer (or electrode), ensuring effective coverage of the "wetting blind zone" and "venting dead zone," while slightly leaving the edges open helps maintain the overall structural integrity of the electrode. Controlling the depth of the channels provides sufficiently unobstructed three-dimensional flow channels to promote fluid flow and gas expulsion while avoiding excessive weakening of the coating's mechanical strength or damage to the current collector. Through the coordinated design of the above dimensional parameters, sufficient liquid guiding and venting space is ensured, while avoiding damage to the overall structure of the electrode due to excessively wide or deep channels. This prevents the electrode from breaking or deforming during processing, assembly, and use, and balances the functionality and mechanical strength of the electrode. Together, they ensure the comprehensive performance advantages of the "X" shaped channel in terms of rapid full-area wetting, efficient venting, maintaining electrode structural stability, and adapting to different battery postures.

[0035] According to some embodiments of the present invention, at least one of the first liquid-guiding venting groove, the second liquid-guiding venting groove, the third liquid-guiding venting groove, and the fourth liquid-guiding venting groove has an electrolyte-affinity conductive coating on its inner wall surface. In some embodiments, the inner wall surface of each of the above liquid-guiding venting grooves is provided with an electrolyte-affinity conductive coating.

[0036] According to some embodiments of the present invention, the electrolyte-affinity conductive coating comprises an electrolyte-affinity material, a conductive filler, and a binder. In some embodiments, the electrolyte-affinity conductive coating comprises 30wt% to 50wt% of an electrolyte-affinity material, 40wt% to 60wt% of a conductive filler, and 5wt% to 15wt% of a binder.

[0037] According to some embodiments of the present invention, the electrophilic material comprises surface-modified nano-SiO2, wherein the surface-modified nano-SiO2 is nano-SiO2 with electrophilic groups grafted onto its surface. In some embodiments, the electrophilic groups include hydroxyl groups; that is, the surface-modified nano-SiO2 comprises surface-hydroxylated modified nano-SiO2, which, by introducing hydroxyl groups (-OH) onto the surface of nano-SiO2, can significantly enhance the hydrogen bonding between nano-SiO2 and the electrolyte, thereby achieving superelectrophilic properties. In some embodiments, the surface hydroxyl content in the surface-hydroxylated modified nano-SiO2 is ≥3.2 mmol / g. In some embodiments, the surface hydroxyl content in the surface-hydroxylated modified nano-SiO2 is 3.2 mmol / g to 5.0 mmol / g. The hydroxyl content can be determined by titration.

[0038] According to some embodiments of the present invention, the conductive filler may include, but is not limited to, at least one of graphene and carbon black.

[0039] According to some embodiments of the present invention, the adhesive may include, but is not limited to, polyvinylidene fluoride (PVDF).

[0040] According to some embodiments of the present invention, the contact angle of the electrolyte on the surface of the electrolyte-affinity conductive coating is less than 15°. In some embodiments, the electrolyte is a 1 mol / L LiPF6 electrolyte, wherein the solvent is ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and propyl propionate (PP) in a volume ratio of 1.2:1:4:4.

[0041] According to some embodiments of the present invention, the conductivity of the electrolyte-affinity conductive coating is 10. -3 S / cm or higher.

[0042] In some embodiments, the contact angle of the electrolyte on the surface of the electrolyte-affinity conductive coating is less than 15°, and the conductivity of the electrolyte-affinity conductive coating is less than 10. -3 S / cm or higher.

[0043] The above describes the application of an electrolyte-affinity conductive coating on the inner wall of the liquid-conducting and venting groove. This coating can be made from electrolyte-affinity materials (such as modified nano-SiO2 grafted with electrolyte-affinity groups) and conductive fillers, achieving a balance between high wettability and conductivity. It can improve wettability while reducing internal resistance. Furthermore, the conductivity of the electrolyte-affinity conductive coating can be controlled within 10-1. -3 With an S / cm or higher and an electrolyte contact angle below 15° on its surface, the electrolyte-affinity conductive coating exhibits super electrolyte affinity and high conductivity. This electrolyte-affinity conductive coating, combined with the electrolyte-conducting and venting channel structure, forms a dual-drive mechanism of "capillary action" and "material affinity," achieving an effect from "physical drainage" to "enhanced material-structure coupling." This overcomes the bottleneck of low-temperature and low-concentration electrolytes, further improving the wetting and diffusion rate of the electrolyte within the electrolyte-conducting and venting channels. Simultaneously, it reduces venting resistance, further mitigating "wetting-venting resistance." Furthermore, this electrolyte-affinity conductive coating possesses good conductivity and structural stability, does not affect electrode ion transport, is adaptable to charge-discharge cycles, reduces interfacial impedance, and promotes uniform electrochemical reactions. Its excellent conductivity and high electrolyte wettability enhance electrochemical reaction efficiency, improving battery rate performance and energy density.

[0044] According to some embodiments of the present invention, the electrolyte-affinity conductive coating comprises a modified polyolefin and a conductive agent, wherein the modified polyolefin is a polyolefin with polar groups grafted onto its molecular chain. In some embodiments, the modified polyolefin is a polyolefin grafted with maleic anhydride, including but not limited to maleic anhydride-grafted polyethylene (PE) and maleic anhydride-grafted polypropylene (PP). By modifying the polyolefin using a maleic anhydride grafting modification process, polar groups are introduced onto the polyolefin molecular chain through a grafting reaction, which can significantly improve the polarity and adhesion of the polyolefin, thereby greatly reducing the contact angle between the electrolyte and the coating surface and improving wettability. In some embodiments, the conductive agent is a composite conductive agent of conductive carbon black and carbon nanotubes (CNTs); wherein the mass ratio of conductive carbon black to CNTs can be controlled to be 10:1. In some embodiments, the electrolyte-affinity conductive coating may also contain auxiliary agents, such as leveling agents and dispersants. In some embodiments, the electrolyte-affinity conductive coating comprises modified polyolefin, conductive carbon black, CNTs, and dispersant in a mass ratio of 50:20:2:3. Furthermore, the electrolyte affinity coating can be prepared by mixing the above raw materials with solvents to form a slurry, and then by coating process; wherein, the solvent can be one or more of toluene, xylene, and butyl acetate; the solvent content in the slurry can be controlled to be 25 wt%.

[0045] According to some embodiments of the present invention, the electrolyte-affinity conductive coating comprises modified graphene and a binder, wherein the modified graphene is hydroxyl- or carboxyl-modified graphene. Specifically, a functionalization modification process can be used to modify the graphene with hydroxyl or carboxyl groups, which can improve its dispersibility in the solvent during the coating preparation process, while enhancing its compatibility with the binder, thereby improving the wettability and conductivity of the coating and avoiding the decrease in liquid conductivity and electrical conductivity caused by graphene agglomeration. In some embodiments, the binder may be at least one of modified PVDF, waterborne styrene-butadiene rubber (SBR), and polyurethane (PU); in some embodiments, the mass ratio of modified graphene to binder can be controlled at 2:1. In some embodiments, the electrolyte-affinity conductive coating further comprises a dispersant, which may include, but is not limited to, polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG); in addition, the mass ratio of modified graphene, binder, and dispersant can be controlled at 10:5:1. Furthermore, the electrolyte affinity coating can be prepared by mixing the above raw materials with a solvent to form a slurry, and then by a coating process; wherein, the solvent can be water or N-methylpyrrolidone (NMP); the solvent content in the slurry can be controlled to be 52 wt%.

[0046] According to some embodiments of the present invention, the active material layer is disposed on both sides of the current collector, specifically, the active material layer is disposed on both sides of the current collector in the thickness direction.

[0047] In some embodiments, the surface of the active material layer facing away from the current collector is square. In some embodiments, the active material layer is disposed on at least one side surface of the current collector and fully covers the surface of the current collector.

[0048] According to some embodiments of the invention, the electrode is a positive electrode, the current collector is a positive current collector, and the active material layer is a positive active material layer.

[0049] In some embodiments, the positive electrode active material layer includes a positive electrode active substance, a conductive agent, and a binder.

[0050] In some embodiments, the positive electrode active material may be one or more of lithium cobalt oxide, ternary materials, lithium-rich materials, or other positive electrode active materials.

[0051] According to some embodiments of the present invention, the electrode is a negative electrode, the current collector is a negative electrode current collector, and the active material layer is a negative electrode active material layer.

[0052] A second aspect of the present invention provides a method for preparing the aforementioned electrode sheet, comprising the following steps: S1. An active material layer is constructed on at least one side surface of the current collector; the active material layer has a central region and a first corner region, a second corner region, a third corner region and a fourth corner region arranged sequentially along the circumference of the central region; the first corner region and the third corner region are arranged opposite to each other, and the second corner region and the fourth corner region are arranged opposite to each other; S2. A first liquid-guiding and venting groove, a second liquid-guiding and venting groove, a third liquid-guiding and venting groove, and a fourth liquid-guiding and venting groove are formed on the active material layer; one end of the first liquid-guiding and venting groove, the second liquid-guiding and venting groove, the third liquid-guiding and venting groove, and the fourth liquid-guiding and venting groove converge and connect in the central region, and the other end extends to the first corner region, the second corner region, the third corner region, and the fourth corner region, respectively.

[0053] The technical solution of the electrode preparation method of the present invention has at least the following beneficial effects: The electrode preparation method of the embodiments of the present invention can produce the aforementioned electrode of the present invention. Therefore, the electrode preparation method has all the beneficial effects of the electrode, which will not be repeated here.

[0054] According to some embodiments of the present invention, on the active material layer constructed in step S1, the diagonal line connecting the first corner region and the third corner region forms a first diagonal line, and the diagonal line connecting the second corner region and the fourth corner region forms a second diagonal line, and the first diagonal line and the second diagonal line intersect at the central region. In step S2, the first and third liquid-guiding venting channels on the active material layer are connected at one end, with the connection point located at the intersection of the first and second diagonals, and the first and third liquid-guiding venting channels are arranged along the first diagonal direction. Simultaneously, the second and fourth liquid-guiding venting channels on the active material layer are connected at one end, with the connection point located at the intersection of the first and second diagonals, and the second and fourth liquid-guiding venting channels are arranged along the second diagonal direction. That is, in step S2, two liquid-guiding venting channels can be formed along the diagonals of the active material layer, and the two channels are arranged intersecting in an "X" shape.

[0055] According to some embodiments of the present invention, the method for preparing the electrode further includes: Step S3: Apply an electrolyte-affinity conductive coating to the inner wall surface of at least one of the first liquid-conducting venting groove, the second liquid-conducting venting groove, the third liquid-conducting venting groove, and the fourth liquid-conducting venting groove.

[0056] In some embodiments, step S3 specifically includes: preparing an electrolyte-affinity conductive slurry by mixing raw materials including an electrolyte-affinity material, a conductive filler, and a binder with a solvent; then coating the inner wall surface of at least one of the first liquid-conducting venting groove, the second liquid-conducting venting groove, the third liquid-conducting venting groove, and the fourth liquid-conducting venting groove with the electrolyte-affinity conductive slurry; and drying to form an electrolyte-affinity conductive coating.

[0057] In some embodiments, in step S3, the inner wall surfaces of the first liquid-conducting venting groove, the second liquid-conducting venting groove, the third liquid-conducting venting groove, and the fourth liquid-conducting venting groove are all coated with the functional conductive paste to construct an electrolyte-affinity conductive coating.

[0058] In a third aspect, the present invention provides a battery comprising any of the aforementioned electrode sheets or an electrode sheet prepared by any of the aforementioned electrode sheet preparation methods of the present invention.

[0059] The technical solution of the present invention regarding the battery has at least the following beneficial effects: The battery of the present invention includes any of the electrode sheets described above or the electrode sheets prepared by any of the electrode sheets described above. Therefore, the battery has all the beneficial effects of the electrode sheets or the electrode sheet preparation methods, which will not be repeated here.

[0060] According to some embodiments of the present invention, the battery includes a casing, a bare cell, and an electrolyte. The bare cell and the electrolyte are housed within the casing. The bare cell includes a positive electrode, a negative electrode, and a separator, with the separator sandwiched between the positive and negative electrode. The positive electrode and / or the negative electrode is any of the electrode types described above or prepared by any of the aforementioned electrode types. That is, the above-mentioned liquid-conducting and venting grooves can be disposed on the active material layer of the positive electrode or the active material layer of the negative electrode, or simultaneously on the active material layers of both electrodes. It is not limited to a single electrode type and can be flexibly adjusted according to different battery design requirements, adapting to the electrode structures of various batteries (such as lithium-ion batteries), exhibiting strong versatility and practicality. The battery includes the above electrode structure. When the electrodes and separator are stacked alternately, the liquid guiding and venting function of the liquid guiding and venting grooves on the active material layer of the electrode can act on the whole cell, accelerate the distribution of electrolyte inside the cell, and timely discharge the gas generated inside the cell. This avoids local electrolyte shortage or gas accumulation inside the cell, reduces the risk of battery bulging and thermal runaway, and ensures the long-term reliability and safety of the battery.

[0061] According to some embodiments of the present invention, the electrolyte comprises an electrolyte salt and an organic solvent. The specific types and compositions of the electrolyte salt and the organic solvent are not specifically limited. In some embodiments, the electrolyte may further comprise positive electrode film-forming additives, negative electrode film-forming additives, and functional additives to improve cycle and low-temperature performance.

[0062] According to some embodiments of the present invention, the diaphragm may include, but is not limited to, a polyethylene membrane, a polypropylene membrane, a polyvinylidene fluoride membrane, or a composite membrane thereof.

[0063] According to some embodiments of the present invention, the battery is a stacked battery, specifically, but not limited to, any one of square stacked batteries, irregularly shaped stacked batteries, stepped stacked batteries, and steel-cased stacked batteries.

[0064] In a fourth aspect, the present invention provides an electrical device comprising any of the batteries described above.

[0065] In some embodiments of the present invention, the electrical equipment includes, but is not limited to, mobile phones, smartphones, laptops, tablets, wearable devices, smartwatches, smart bracelets, smart glasses, power banks, televisions, game consoles, game controllers, digital cameras, smart speakers, headphones, keyboards, mice, monitors, drones, audio equipment, home appliances, toys, power tools, automobiles, motorcycles, electric bicycles, bicycles, robots, robot dogs, industrial robots, and android robots. Attached Figure Description

[0066] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the positive electrode sheet of Example 1 from the perspective of the positive electrode active material layer; Figure 2 This is a schematic diagram of the negative electrode sheet in Example 1 from the perspective of the negative electrode active material layer. Detailed Implementation

[0067] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0068] In the following examples and comparative examples, a battery with a positive electrode sheet length × width of 90 mm × 70 mm and a single-sided thickness H1 of 60 μm for the positive electrode active material layer, and a negative electrode sheet length × width of 91.2 mm × 70.8 mm and a single-sided thickness H2 of 50 μm for the negative electrode active material layer are used as examples for illustration.

[0069] Example 1 This embodiment proposes a positive electrode plate, such as... Figure 1As shown, the device includes a positive current collector and positive active material layers 10 disposed on both sides of the positive current collector. The positive current collector is an aluminum foil. The positive active material layers 10 include positive active material LiCoO2, conductive agent acetylene black, conductive carbon nanotubes, and binder polyvinylidene fluoride (PVDF) in a mass ratio of 97.6:0.5:0.6:1.3. The positive active material layers 10 are rectangular, with a length a1 × width b1 of 90 mm × 70 mm and a single-sided thickness H1 of 60 μm.

[0070] The positive electrode active material layer 10 has two liquid guiding and venting grooves, namely liquid guiding and venting groove one 11 and liquid guiding and venting groove two 12. The two liquid guiding and venting grooves are respectively arranged in an "X" shape along the two diagonals of the positive electrode active material layer 10, and the two liquid guiding and venting grooves are symmetrically arranged with respect to the intersection point.

[0071] Alternatively, the positive electrode active material layer 10 can be understood as having a central region, and also having a first diagonal and a second diagonal that are intersected, as well as a first corner region 13, a second corner region 14, a third corner region 15, and a fourth corner region 16 arranged sequentially along the circumference of the central region; the first corner region 13 and the third corner region 15 are arranged opposite each other, and the first diagonal connects the diagonal between the first corner region 13 and the third corner region 15; the second corner region 14 and the fourth corner region 16 are arranged opposite each other, and the second diagonal connects the diagonal between the second corner region 14 and the fourth corner region 16, and the first diagonal and the second diagonal intersect at the central region. The positive electrode active material layer 10 has a first liquid guiding and venting groove 111, a second liquid guiding and venting groove 121, a third liquid guiding and venting groove 112, and a fourth liquid guiding and venting groove 122. One end of the first liquid guiding and venting groove 111, the second liquid guiding and venting groove 121, the third liquid guiding and venting groove 112, and the fourth liquid guiding and venting groove 122 converges and connects in the central region, and the other end extends to the first corner region 13, the second corner region 14, the third corner region 15, and the fourth corner region 16, respectively. One end of the first liquid guiding and venting groove 111 located in the central region is connected to one end of the third liquid guiding and venting groove 112 located in the central region, and the connection position is located at the intersection of the first diagonal and the second diagonal. The first liquid-guiding venting channel 111 and the third liquid-guiding venting channel 112 are arranged along the first diagonal direction, and the two are connected to form a first liquid-guiding venting channel 11; one end of the second liquid-guiding venting channel 121 located in the central region is connected to one end of the fourth liquid-guiding venting channel 122 located in the central region, and the connection position is located at the intersection of the first diagonal and the second diagonal. The second liquid-guiding venting channel 121 and the fourth liquid-guiding venting channel 122 are arranged along the second diagonal direction, and the two are connected to form a second liquid-guiding venting channel 12; the first liquid-guiding venting channel 111 and the third liquid-guiding venting channel 112 are symmetrically arranged along the intersection of the first diagonal and the second diagonal; the second liquid-guiding venting channel 121 and the fourth liquid-guiding venting channel 122 are symmetrically arranged along the intersection of the first diagonal and the second diagonal.

[0072] The lengths of the two liquid guiding and venting channels (i.e., liquid guiding and venting channel 11 and liquid guiding and venting channel 212) are both 92% × =105mm, width W1 is 0.5mm, depth h1 is 2 / 5, H1=24μm. Furthermore, the inner walls of both liquid-conducting and venting channels are covered with an electrolyte-affinity conductive coating. This coating comprises 40wt% electrolyte-affinity material, 50wt% conductive filler, and 10wt% binder. The electrolyte-affinity material is surface-hydroxylated nano-SiO2, which is obtained by surface modification of nano-SiO2 with silane coupling agent KH-550, with KH-550 accounting for 5% of the nano-SiO2 mass. The surface hydroxyl content in the surface-hydroxylated nano-SiO2 is ≥3.2mmol / g. The conductive filler is graphene and conductive carbon black (SP) in a mass ratio of 4:3, and the binder is PVDF. The conductivity of this electrolyte-affinity conductive coating was measured to be 10 using the four-point probe method. -2 S / cm.

[0073] The above positive electrode sheet is prepared by the following method: S1. The positive electrode active material LiCoO2, conductive agent acetylene black, conductive carbon nanotubes, and binder PVDF are fully dispersed in an N-methylpyrrolidone (NMP) solvent system at a weight ratio of 97.6:0.5:0.6:1.3 to prepare a positive electrode slurry with a solid content of 75%. The positive electrode slurry is then uniformly coated onto both sides of the positive electrode current collector aluminum foil. After cold pressing, it is die-cut to obtain a positive electrode sheet with a single-sided thickness H1 of 60 μm and a length a1 × width b1 of 90 mm × 70 mm. Then, two intersecting "X"-shaped liquid-conducting and venting grooves are etched along two diagonals on the positive electrode active material layer using laser etching. Both grooves are symmetrically arranged with respect to the intersection of the diagonals, and both grooves have a length of 92% × [missing information - likely a value]. =105mm, width W1 is 0.5mm, depth h1 is 2 / 5, H1=24μm.

[0074] S2. Disperse nano-SiO2 in anhydrous ethanol, sonicate at 300W for 30 min, heat to 60℃, add 5% (by mass) of silane coupling agent KH-550 of nano-SiO2, stir at constant temperature for 2 h, centrifuge, and dry at 100℃ for 2 h to obtain surface-hydroxylated nano-SiO2 (surface hydroxyl content ≥3.2 mmol / g); Mix graphene and SP at a mass ratio of 4:3, then add 1 / 3 (by mass) of NMP of the total mass of graphene and SP, and then add 0.8% (by mass) of decahydrate of NMP. Dialkylphenol polyoxyethylene ether (OP-10) was first stirred at 2000 rpm for 1 hour, followed by ultrasonic dispersion for 30 minutes to form a homogeneous conductive mother liquor. PVDF was added to NMP and stirred at 70°C until completely dissolved. After cooling to room temperature, conductive mother liquor was added at a mass ratio of PVDF to conductive mother liquor of 1:1.6. Surface-hydroxylated nano-SiO2 was added at 6% of the oven-dry mass of PVDF. After stirring for 2 hours, ultrasonic degassing was performed for 15 minutes, finally yielding a final viscosity of 600 mPa. The electrolyte-affinity conductive paste is then coated onto the inner wall of the liquid-conducting and venting groove using a micro-gravure coating process. After drying, an electrolyte-affinity conductive coating with electrolyte affinity is formed, thus producing the positive electrode sheet.

[0075] A 1 mol / L LiPF6 electrolyte was prepared by mixing ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and propyl propionate (PP) in a solvent system with a volume ratio of 1.2:1:4:4 with lithium salt LiPF6. The contact angle θ of the electrolyte affinity conductive coating on the inner wall of the liquid conduction and venting groove on the positive electrode was tested using the capillary rise method.

[0076] Specifically, a conventional reverse calculation method is used to calculate the contact angle. A section of the electrolyte-conducting venting groove (length ≥ 1 cm) is cut from the electrode. Given the surface tension γ of the electrolyte (measured using the platinum plate method) and its density ρ (measured using the specific gravity bottle method), the electrode is vertically inserted into the electrolyte (channel opening downwards). A camera records the change in the capillary rise height h of the electrolyte within the venting groove over time t. After stabilization (usually within 30 seconds), the equilibrium height h is read and substituted into the formula "cosθ = hρgr / 2γ" to calculate the contact angle θ. Where: γ is the electrolyte surface tension, θ is the contact angle between the inner wall of the venting groove and the electrolyte (to be determined), ρ is the electrolyte density, g is the gravitational acceleration, and r is the equivalent radius of the channel (converted from the etching width w; since the venting groove is rectangular, the equivalent radius r ≈ w / 2).

[0077] The contact angle θ of the electrolyte affinity conductive coating on the inner wall of the liquid conduction and venting groove on the positive electrode plate was determined to be 12° using the above method.

[0078] This embodiment also proposes a negative electrode, such as... Figure 2 As shown, it includes a negative electrode current collector and a negative electrode active material layer 20 disposed on both sides of the negative electrode current collector. The negative electrode current collector is a copper foil. The negative electrode active material layer 20 includes a negative electrode active material (silicon-carbon active material with a silicon content of 40%), a conductive agent (conductive carbon black SP and carbon nanotubes CNTs in a mass ratio of 7:4), and a binder (sodium carboxymethyl cellulose CMC and polyacrylic acid PAA in a mass ratio of 6:7) in a negative electrode active material layer 20. The rectangle has a length a2 × width b2 of 91.2 mm × 70.8 mm and a single-sided thickness H2 of 50 μm. The negative electrode active material layer 20 has two liquid-conducting and venting grooves, namely liquid-conducting and venting groove three 21 and liquid-conducting and venting groove four 22. The structure of the two liquid-conducting and venting grooves is similar to that of the liquid-conducting and venting grooves on the positive electrode active material layer 10 of the positive electrode sheet in this embodiment. The two liquid-conducting and venting grooves are respectively arranged in an "X" shape along the two diagonals of the negative electrode active material layer, and the two liquid-conducting and venting grooves are symmetrically arranged with respect to the intersection point.

[0079] Alternatively, the negative electrode active material layer 20 can be understood as having a central region, a first diagonal and a second diagonal that are intersected, and a first corner region 23, a second corner region 24, a third corner region 25 and a fourth corner region 26 arranged sequentially along the circumference of the central region; the first corner region 23 and the third corner region 25 are arranged opposite each other, and the first diagonal connects the diagonal between the first corner region 23 and the third corner region 25; the second corner region 24 and the fourth corner region 26 are arranged opposite each other, and the second diagonal connects the diagonal between the second corner region 24 and the fourth corner region 26, and the first diagonal and the second diagonal intersect in the central region. The negative electrode active material layer 20 has a first liquid guiding and venting groove 211, a second liquid guiding and venting groove 221, a third liquid guiding and venting groove 212, and a fourth liquid guiding and venting groove 222. One end of the first liquid guiding and venting groove 211, the second liquid guiding and venting groove 221, the third liquid guiding and venting groove 212, and the fourth liquid guiding and venting groove 222 converges and connects in the central region, and the other end extends to the first corner region 23, the second corner region 24, the third corner region 25, and the fourth corner region 26, respectively. One end of the first liquid guiding and venting groove 211 located in the central region is connected to one end of the third liquid guiding and venting groove 212 located in the central region, and the connection position is located at the intersection of the first diagonal and the second diagonal. The third liquid-guiding venting channel 212 is arranged along the first diagonal direction, and the two are connected to form the third liquid-guiding venting channel 21; one end of the second liquid-guiding venting channel 221 located in the central region is connected to one end of the fourth liquid-guiding venting channel 222 located in the central region, and the connection position is located at the intersection of the first diagonal and the second diagonal. The second liquid-guiding venting channel 221 and the fourth liquid-guiding venting channel 222 are arranged along the second diagonal direction, and the two are connected to form the fourth liquid-guiding venting channel 22; the first liquid-guiding venting channel 211 and the third liquid-guiding venting channel 212 are symmetrically arranged along the intersection of the first diagonal and the second diagonal; the second liquid-guiding venting channel 221 and the fourth liquid-guiding venting channel 222 are symmetrically arranged along the intersection of the first diagonal and the second diagonal.

[0080] The lengths of the two liquid guiding and venting channels (i.e., liquid guiding and venting channel three 21 and liquid guiding and venting channel four 22) are both 92% × =106mm, width W2 is 0.5mm, depth h2 is 2 / 5, H2=20μm. Furthermore, the inner walls of both liquid-conducting and venting channels are covered with an electrolyte-affinity conductive coating, which is the same as the electrolyte-affinity conductive coating provided on the inner wall surface of the liquid-conducting and venting channels on the positive electrode active material layer of the positive electrode sheet.

[0081] The above negative electrode sheet is prepared by the following method: S1. The negative electrode active material, conductive agent, and binder are fully dispersed in a deionized water solvent system at a weight ratio of 97.6:1.1:1.3 to prepare a negative electrode slurry with a solid content of 40%. The negative electrode slurry is then uniformly coated onto both sides of the negative electrode current collector copper foil. After cold pressing, it is die-cut to obtain a negative electrode sheet with a single-sided thickness H2 of 50 μm and a length a2 × width b2 of 91.2 mm × 70.8 mm. Then, two intersecting "X"-shaped liquid guiding and venting grooves are etched on the negative electrode active material layer along two diagonals using a laser etching process. Both liquid guiding and venting grooves are symmetrically arranged with respect to the intersection point, and the length of both liquid guiding and venting grooves is 92% × =106mm, width W2 is 0.5mm, depth h2 is 2 / 5, H2=20μm.

[0082] S2. Following the same procedure as step S2 in the preparation method of the positive electrode sheet in this embodiment, an electrolyte affinity conductive coating is applied to the inner wall of the liquid-conducting and venting groove on the negative electrode active material layer to obtain the negative electrode sheet.

[0083] Using the same contact angle test method as above, the contact angle θ of the electrolyte affinity conductive coating on the inner wall of the liquid conduction and exhaust groove on the negative electrode sheet with a concentration of 1 mol / L LiPF6 electrolyte (solvents in a volume ratio of 1.2:1:4:4 EC, PC, DEC and PP) was also 12°.

[0084] This embodiment also proposes a battery, which is a stacked battery, comprising a casing, bare cells, and an electrolyte, with the bare cells and electrolyte housed within the casing. The bare cells include a positive electrode, a separator, and a negative electrode, with the positive and negative electrodes being the same as described above in this embodiment. The separator is sandwiched between the positive and negative electrodes and is specifically a PE separator with a ceramic coating on its surface. The ceramic coating material comprises 94 wt% inorganic ceramic filler (SiO2 and Al2O3 in a mass ratio of 7:3), 4 wt% aqueous binder (PVDF and CMC in a mass ratio of 5:3), and 2 wt% dispersant sodium polyacrylate, with a ceramic coating thickness of 2.5 μm. The electrolyte is a 1 mol / L LiPF6 electrolyte (solvents are EC, PC, DEC, and PP in a volume ratio of 1.2:1:4:4). Furthermore, in this embodiment of the battery, both the positive and negative electrode plates include two diagonally intersecting drainage grooves with an electrolyte-affinity conductive coating on their inner walls.

[0085] The above battery is prepared by the following steps: stacking positive electrode, separator and negative electrode to form a bare cell, placing the bare cell in the casing, injecting electrolyte into the casing, and then encapsulating to obtain the battery.

[0086] Example 2 This embodiment proposes a battery that differs from Embodiment 1 in that the negative electrode active material layer of the negative electrode sheet used in this embodiment contains only one liquid-guiding and venting groove arranged along the diagonal of the negative electrode active material layer. That is, only the number of liquid-guiding and venting grooves on the negative electrode sheet is adjusted from two in Embodiment 1 to one; everything else is the same as the battery in Embodiment 1. Furthermore, in this embodiment, the positive electrode sheet contains two liquid-guiding and venting grooves arranged diagonally and having an electrolyte-affinity conductive coating on its inner wall surface, while the negative electrode sheet contains only one liquid-guiding and venting groove arranged diagonally and having an electrolyte-affinity conductive coating on its inner wall surface.

[0087] Example 3 This embodiment proposes a battery that differs from Embodiment 1 in that the negative electrode active material layer of the negative electrode sheet used in this embodiment does not contain liquid-conducting venting grooves. That is, only the number of liquid-conducting venting grooves on the negative electrode sheet is adjusted from two in Embodiment 1 to zero. Correspondingly, the process of etching liquid-conducting venting grooves on the negative electrode active material layer and providing an electrolyte-affinity conductive coating on the inner wall of the liquid-conducting venting grooves, as in Embodiment 1, is omitted during the negative electrode sheet preparation process. Everything else is the same as in Embodiment 1. Furthermore, in this embodiment, the positive electrode sheet includes two diagonally intersecting liquid-conducting venting grooves with an electrolyte-affinity conductive coating on their inner wall, while the negative electrode sheet does not contain any liquid-conducting venting grooves.

[0088] Example 4 This embodiment proposes a battery that differs from Embodiment 1 in that the positive electrode active material layer of the positive electrode sheet used in this embodiment contains only one liquid-conducting and venting groove arranged along the diagonal of the positive electrode active material layer. That is, only the number of liquid-conducting and venting grooves on the positive electrode sheet is adjusted from two in Embodiment 1 to one; everything else is the same as the battery in Embodiment 1. Furthermore, in this embodiment, the positive electrode sheet contains only one liquid-conducting and venting groove arranged diagonally with an electrolyte-affinity conductive coating on its inner wall surface, and the negative electrode sheet contains two liquid-conducting and venting grooves arranged diagonally and intersecting each other with an electrolyte-affinity conductive coating on their inner wall surfaces.

[0089] Example 5 This embodiment proposes a battery that differs from Embodiment 1 in that the positive electrode active material layer of the positive electrode sheet used in this embodiment does not contain liquid-conducting venting grooves. That is, only the number of liquid-conducting venting grooves on the positive electrode sheet is changed from two in Embodiment 1 to zero. Correspondingly, the operations of etching liquid-conducting venting grooves on the positive electrode active material layer and providing an electrolyte-affinity conductive coating on the inner wall surface of the liquid-conducting venting grooves, as in Embodiment 1, are omitted during the positive electrode sheet preparation process. Everything else is the same as in Embodiment 1. Furthermore, in this embodiment, the positive electrode sheet does not contain liquid-conducting venting grooves, while the negative electrode sheet contains two diagonally intersecting liquid-conducting venting grooves with an electrolyte-affinity conductive coating on their inner wall surface.

[0090] Example 6 This embodiment proposes a positive electrode sheet, which differs from the positive electrode sheet in Embodiment 1 in that the depth of the liquid-conducting and venting groove on the positive electrode active material layer is adjusted from 24μm in Embodiment 1 to 12μm, while the rest is the same as the positive electrode sheet in Embodiment 1.

[0091] This embodiment also proposes a negative electrode sheet, which differs from the negative electrode sheet in Embodiment 1 in that the depth of the liquid guiding and venting groove on the negative electrode active material layer in this embodiment is adjusted from 20μm in Embodiment 1 to 10μm, while the rest is the same as the negative electrode sheet in Embodiment 1.

[0092] This embodiment also proposes a battery that differs from the battery of Embodiment 1 in that the battery of this embodiment uses the positive electrode and the negative electrode of this embodiment to replace the positive electrode and the negative electrode used in the battery of Embodiment 1, while the rest is the same as the battery of Embodiment 1.

[0093] Example 7 This embodiment proposes a positive electrode sheet, which differs from the positive electrode sheet in Embodiment 1 in that the depth of the liquid-conducting and venting groove on the positive electrode active material layer is adjusted from 24μm in Embodiment 1 to 14μm, while the rest is the same as the positive electrode sheet in Embodiment 1.

[0094] This embodiment also proposes a negative electrode sheet, which differs from the negative electrode sheet in Embodiment 1 in that the depth of the liquid guiding and venting groove on the negative electrode active material layer in this embodiment is adjusted from 20μm in Embodiment 1 to 12μm, while the rest is the same as the negative electrode sheet in Embodiment 1.

[0095] This embodiment also proposes a battery that differs from the battery of Embodiment 1 in that the battery of this embodiment uses the positive electrode and the negative electrode of this embodiment to replace the positive electrode and the negative electrode used in the battery of Embodiment 1, while the rest is the same as the battery of Embodiment 1.

[0096] Example 8 This embodiment proposes a positive electrode sheet, which differs from the positive electrode sheet in Embodiment 1 in that the depth of the liquid-conducting and venting groove on the positive electrode active material layer is adjusted from 24μm in Embodiment 1 to 28μm, while the rest is the same as the positive electrode sheet in Embodiment 1.

[0097] This embodiment also proposes a negative electrode sheet, which differs from the negative electrode sheet in Embodiment 1 in that the depth of the liquid guiding and venting groove on the negative electrode active material layer in this embodiment is adjusted from 20μm in Embodiment 1 to 24μm, while the rest is the same as the negative electrode sheet in Embodiment 1.

[0098] This embodiment also proposes a battery that differs from the battery of Embodiment 1 in that the battery of this embodiment uses the positive electrode and the negative electrode of this embodiment to replace the positive electrode and the negative electrode used in the battery of Embodiment 1, while the rest is the same as the battery of Embodiment 1.

[0099] Example 9 This embodiment proposes a positive electrode sheet, which differs from the positive electrode sheet in Embodiment 1 in that the depth of the liquid-conducting and venting groove on the positive electrode active material layer is adjusted from 24μm in Embodiment 1 to 30μm, while the rest is the same as the positive electrode sheet in Embodiment 1.

[0100] This embodiment also proposes a negative electrode sheet, which differs from the negative electrode sheet in Embodiment 1 in that the depth of the liquid guiding and venting groove on the negative electrode active material layer in this embodiment is adjusted from 20μm in Embodiment 1 to 25μm, while the rest is the same as the negative electrode sheet in Embodiment 1.

[0101] This embodiment also proposes a battery that differs from the battery of Embodiment 1 in that the battery of this embodiment uses the positive electrode and the negative electrode of this embodiment to replace the positive electrode and the negative electrode used in the battery of Embodiment 1, while the rest is the same as the battery of Embodiment 1.

[0102] Example 10 This embodiment proposes a positive electrode and a negative electrode, which differ from the positive electrode and negative electrode in Embodiment 1 in that the width of the liquid guiding and venting groove on the active material layer in this embodiment is adjusted from 0.5 mm in Embodiment 1 to 0.04 mm, while the other dimensions are the same as those in the positive electrode and negative electrode in Embodiment 1.

[0103] This embodiment also proposes a battery that differs from the battery of Embodiment 1 in that the battery of this embodiment uses the positive electrode and the negative electrode of this embodiment to replace the positive electrode and the negative electrode used in the battery of Embodiment 1, while the rest is the same as the battery of Embodiment 1.

[0104] Example 11 This embodiment proposes a positive electrode and a negative electrode, which differ from the positive electrode and negative electrode in Embodiment 1 in that the width of the liquid guiding and venting groove on the active material layer in this embodiment is adjusted from 0.5 mm in Embodiment 1 to 0.05 mm, while the other dimensions are the same as those in the positive electrode and negative electrode in Embodiment 1.

[0105] This embodiment also proposes a battery that differs from the battery of Embodiment 1 in that the battery of this embodiment uses the positive electrode and the negative electrode of this embodiment to replace the positive electrode and the negative electrode used in the battery of Embodiment 1, while the rest is the same as the battery of Embodiment 1.

[0106] Example 12 This embodiment proposes a positive electrode and a negative electrode, which differ from the positive electrode and negative electrode in Embodiment 1 in that the width of the liquid guiding and venting groove on the active material layer in the positive electrode and negative electrode of this embodiment is adjusted from 0.5 mm in Embodiment 1 to 1 mm, while the other aspects are the same as the positive electrode and negative electrode in Embodiment 1.

[0107] This embodiment also proposes a battery that differs from the battery of Embodiment 1 in that the battery of this embodiment uses the positive electrode and the negative electrode of this embodiment to replace the positive electrode and the negative electrode used in the battery of Embodiment 1, while the rest is the same as the battery of Embodiment 1.

[0108] Example 13 This embodiment proposes a positive electrode and a negative electrode, which differ from the positive electrode and negative electrode in Embodiment 1 in that the width of the liquid guiding and venting groove on the active material layer in this embodiment is adjusted from 0.5 mm in Embodiment 1 to 1.2 mm, while the other dimensions are the same as those in the positive electrode and negative electrode in Embodiment 1.

[0109] This embodiment also proposes a battery that differs from the battery of Embodiment 1 in that the battery of this embodiment uses the positive electrode and the negative electrode of this embodiment to replace the positive electrode and the negative electrode used in the battery of Embodiment 1, while the rest is the same as the battery of Embodiment 1.

[0110] Example 14 This embodiment proposes a positive electrode sheet, which differs from the positive electrode sheet in Embodiment 1 in that the length of the liquid-conducting and venting groove on the positive electrode active material layer is adjusted from 105mm in Embodiment 1 to 101mm, while the rest is the same as the positive electrode sheet in Embodiment 1.

[0111] This embodiment also proposes a negative electrode sheet, which differs from the negative electrode sheet in Embodiment 1 in that: in the negative electrode sheet of this embodiment, the length of the liquid guiding and venting groove on the negative electrode active material layer is adjusted from 106mm in Embodiment 1 to 102mm, while the rest is the same as the negative electrode sheet of Embodiment 1.

[0112] This embodiment also proposes a battery that differs from the battery of Embodiment 1 in that the battery of this embodiment uses the positive electrode and the negative electrode of this embodiment to replace the positive electrode and the negative electrode used in the battery of Embodiment 1, while the rest is the same as the battery of Embodiment 1.

[0113] Example 15 This embodiment proposes a positive electrode sheet, which differs from the positive electrode sheet in Embodiment 1 in that the length of the liquid-conducting and venting groove on the positive electrode active material layer is adjusted from 105 mm in Embodiment 1 to 103 mm, while the rest is the same as the positive electrode sheet in Embodiment 1.

[0114] This embodiment also proposes a negative electrode sheet, which differs from the negative electrode sheet in Embodiment 1 in that: in the negative electrode sheet of this embodiment, the length of the liquid guiding and venting groove on the negative electrode active material layer is adjusted from 106mm in Embodiment 1 to 104mm, while the rest is the same as the negative electrode sheet of Embodiment 1.

[0115] This embodiment also proposes a battery that differs from the battery of Embodiment 1 in that the battery of this embodiment uses the positive electrode and the negative electrode of this embodiment to replace the positive electrode and the negative electrode used in the battery of Embodiment 1, while the rest is the same as the battery of Embodiment 1.

[0116] Example 16 This embodiment proposes a positive electrode sheet, which differs from the positive electrode sheet in Embodiment 1 in that the length of the liquid-conducting and venting groove on the positive electrode active material layer is adjusted from 105mm in Embodiment 1 to 108mm, while the rest is the same as the positive electrode sheet in Embodiment 1.

[0117] This embodiment also proposes a negative electrode sheet, which differs from the negative electrode sheet in Embodiment 1 in that: in the negative electrode sheet of this embodiment, the length of the liquid guiding and venting groove on the negative electrode active material layer is adjusted from 106mm in Embodiment 1 to 109mm, while the rest is the same as the negative electrode sheet of Embodiment 1.

[0118] This embodiment also proposes a battery that differs from the battery of Embodiment 1 in that the battery of this embodiment uses the positive electrode and the negative electrode of this embodiment to replace the positive electrode and the negative electrode used in the battery of Embodiment 1, while the rest is the same as the battery of Embodiment 1.

[0119] Example 17 This embodiment proposes a positive electrode sheet, which differs from the positive electrode sheet in Embodiment 1 in that the length of the liquid-conducting and venting groove on the positive electrode active material layer is adjusted from 105mm in Embodiment 1 to 114mm, while the rest is the same as the positive electrode sheet in Embodiment 1.

[0120] This embodiment also proposes a negative electrode sheet, which differs from the negative electrode sheet in Embodiment 1 in that: in the negative electrode sheet of this embodiment, the length of the liquid guiding and venting groove on the negative electrode active material layer is adjusted from 106mm in Embodiment 1 to 115mm, while the rest is the same as the negative electrode sheet of Embodiment 1.

[0121] This embodiment also proposes a battery that differs from the battery of Embodiment 1 in that the battery of this embodiment uses the positive electrode and the negative electrode of this embodiment to replace the positive electrode and the negative electrode used in the battery of Embodiment 1, while the rest is the same as the battery of Embodiment 1.

[0122] Example 18 This embodiment proposes a positive electrode and a negative electrode, which differ from the positive electrode and negative electrode in Embodiment 1 in that: in the positive electrode and negative electrode of this embodiment, the electrolyte affinity conductive coating is removed from the inner wall surface of the liquid-conducting and venting groove on the active material layer, while the rest is the same as the positive electrode and negative electrode in Embodiment 1.

[0123] Using the same contact angle testing method as in Example 1, the contact angle θ of the inner wall surface of the liquid conduction and venting groove on both the positive and negative electrode plates in this example was 30° for a 1 mol / L LiPF6 electrolyte (solvents were EC, PC, DEC and PP in a volume ratio of 1.2:1:4:4).

[0124] This embodiment also proposes a battery that differs from the battery of Embodiment 1 in that the battery of this embodiment uses the positive electrode and the negative electrode of this embodiment to replace the positive electrode and the negative electrode used in the battery of Embodiment 1, while the rest is the same as the battery of Embodiment 1.

[0125] Comparative Example 1 This comparative example presents a positive electrode sheet, which differs from the positive electrode sheet in Example 1 in that: the positive active material layer of this comparative example positive electrode sheet does not contain liquid-conducting and venting grooves. Correspondingly, the preparation process of this positive electrode sheet eliminates the operations of etching and setting liquid-conducting and venting grooves on the positive active material layer and setting an electrolyte affinity conductive coating on the inner wall surface of the liquid-conducting and venting grooves in the preparation method of the positive electrode sheet in Example 1. Otherwise, it is the same as the positive electrode sheet and its preparation method in Example 1.

[0126] This comparative example also proposes a negative electrode sheet, which differs from the negative electrode sheet of Example 1 in that: the negative electrode active material layer of this comparative example negative electrode sheet does not contain liquid-conducting and venting grooves. Correspondingly, the preparation process of this negative electrode sheet eliminates the operation of etching and setting liquid-conducting and venting grooves on the negative electrode active material layer and setting an electrolyte affinity conductive coating on the inner wall surface of the liquid-conducting and venting grooves in the preparation method of the negative electrode sheet of Example 1. Otherwise, it is the same as the negative electrode sheet of Example 1 and its preparation method.

[0127] This comparative example also proposes a battery that differs from the battery of Example 1 in that: the positive and negative electrode plates of this comparative example are used instead of those used in the battery of Example 1, while the rest are the same as those of the battery of Example 1. Furthermore, in this comparative example battery, neither the positive nor the negative electrode plate contains a liquid-conducting venting groove.

[0128] Comparative Example 2 This comparative example presents a positive electrode sheet, which differs from the positive electrode sheet in Example 1 in that: the positive electrode active material layer of this comparative example positive electrode sheet contains only one liquid guiding and venting groove arranged along the diagonal of the positive electrode active material layer. That is, only the number of liquid guiding and venting grooves on the positive electrode sheet is adjusted from two in Example 1 to one, and the rest is the same as the positive electrode sheet of Example 1.

[0129] This comparative example also proposes a battery that differs from the battery of Example 1 in that: the positive electrode of this comparative example battery is used instead of the positive electrode of the battery of Example 1, and the negative electrode of Comparative Example 1 is used instead of the negative electrode of Example 1; otherwise, it is the same as the battery of Example 1. Furthermore, in this comparative example battery, the positive electrode has only one liquid-conducting and venting groove arranged diagonally and having an electrolyte-affinity conductive coating on its inner wall surface, while the negative electrode does not have a liquid-conducting and venting groove.

[0130] Comparative Example 3 This comparative example proposes a negative electrode sheet, which differs from the negative electrode sheet in Example 1 in that: the negative electrode active material layer of this comparative example negative electrode sheet contains only one liquid guiding and venting groove arranged along the diagonal of the negative electrode active material layer. That is, only the number of liquid guiding and venting grooves on the negative electrode sheet is adjusted from two in Example 1 to one, and the rest is the same as the negative electrode sheet of Example 1.

[0131] This comparative example also proposes a battery that differs from the battery of Example 1 in that: the positive electrode sheet of Comparative Example 1 is used instead of the positive electrode sheet used in the battery of Example 1, and the negative electrode sheet of this comparative example is used instead of the negative electrode sheet used in Example 1; otherwise, it is the same as the battery of Example 1. Furthermore, in this comparative example battery, the positive electrode sheet does not contain a liquid-conducting venting groove, and the negative electrode sheet only contains one liquid-conducting venting groove arranged diagonally with an electrolyte-affinity conductive coating on its inner wall surface.

[0132] Comparative Example 4 This comparative example presents a positive electrode sheet, which differs from the positive electrode sheet in Example 1 in that: the liquid-conducting and venting grooves on the positive active material layer of this comparative example positive electrode sheet are adjusted to be arranged along the length direction parallel to the positive electrode sheet, there are two liquid-conducting and venting grooves, and the liquid-conducting and venting grooves are evenly spaced in the width direction of the positive electrode sheet (that is, the positive active material layer is evenly divided into 3 segments in the width direction), and the length of the liquid-conducting and venting grooves is adjusted from 105 mm in Example 1 to 82.8 mm (i.e., 92% a1), and the rest is the same as the positive electrode sheet in Example 1.

[0133] This comparative example also proposes a negative electrode sheet, which differs from the negative electrode sheet of Example 1 in that: the liquid guiding and venting grooves on the negative electrode active material layer of this comparative example negative electrode sheet are adjusted to be set along the length direction parallel to the negative electrode sheet, there are two liquid guiding and venting grooves, and the liquid guiding and venting grooves are evenly spaced in the width direction of the negative electrode sheet (that is, the negative electrode active material layer is evenly divided into 3 segments in the width direction), and the length of the liquid guiding and venting grooves is adjusted from 106 mm in Example 1 to 83.9 mm (i.e. 92% a2), and the rest is the same as the negative electrode sheet of Example 1 and its preparation method.

[0134] This comparative example also proposes a battery that differs from the battery of Example 1 in that: the positive and negative electrode plates used in this comparative example are replaced with those used in the battery of Example 1, while the rest is the same as the battery of Example 1. Furthermore, in this comparative example battery, both the positive and negative electrode plates contain liquid-guiding and venting grooves arranged parallel to the length direction of the electrode plates and having an electrolyte-affinity conductive coating on their inner wall surfaces.

[0135] Comparative Example 5 This comparative example presents a positive electrode sheet, which differs from the positive electrode sheet in Example 1 in that: the liquid-conducting and venting grooves on the positive active material layer of this comparative example positive electrode sheet are adjusted to be arranged along the width direction parallel to the positive electrode sheet, there are two liquid-conducting and venting grooves, and the liquid-conducting and venting grooves are evenly spaced along the length direction of the positive electrode sheet (that is, the positive active material layer is evenly divided into 3 segments along the length direction), and the length of the liquid-conducting and venting grooves is adjusted from 105 mm in Example 1 to 64.4 mm (i.e., 92%b1), and the rest is the same as the positive electrode sheet in Example 1.

[0136] This comparative example also proposes a negative electrode sheet, which differs from the negative electrode sheet of Example 1 in that: the liquid guiding and venting grooves on the negative electrode active material layer of this comparative example negative electrode sheet are adjusted to be set along the width direction parallel to the negative electrode sheet, there are two liquid guiding and venting grooves, and the liquid guiding and venting grooves are evenly spaced along the length direction of the negative electrode sheet (that is, the negative electrode active material layer is evenly divided into 3 segments along the length direction), and the length of the liquid guiding and venting grooves is adjusted from 106 mm in Example 1 to 65.1 mm (i.e. 92%b2), and the rest is the same as the negative electrode sheet of Example 1 and its preparation method.

[0137] This comparative example also proposes a battery that differs from the battery of Example 1 in that: the positive and negative electrode plates used in Comparative Example 1 are replaced with those used in the battery of Example 1, while the rest is the same as the battery of Example 1. Furthermore, in this comparative example battery, both the positive and negative electrode plates contain liquid-guiding and venting grooves arranged parallel to the width direction of the electrode plates and having an electrolyte-affinity conductive coating on their inner wall surfaces.

[0138] Comparative Example 6 This comparative example presents a positive electrode sheet, which differs from the positive electrode sheet in Example 1 in that: the positive active material layer of the positive electrode sheet in this comparative example also has two liquid-conducting and venting grooves. One of the liquid-conducting and venting grooves is set along the length direction parallel to the positive electrode sheet, and its length is 82.8 mm (i.e., 92%a1). The other liquid-conducting and venting groove is set along the width direction parallel to the positive electrode sheet, and its length is 64.4 mm (i.e., 92%b1). The two liquid-conducting and venting grooves are arranged in a cross shape, and the intersection point is located at the intersection of two diagonals in the central area of ​​the positive electrode sheet. The two liquid-conducting and venting grooves are also symmetrically arranged with respect to the intersection point. Other aspects are the same as the positive electrode sheet in Example 1.

[0139] This comparative example also proposes a negative electrode sheet, which differs from the negative electrode sheet of Example 1 in that: the negative electrode active material layer of this comparative example negative electrode sheet also has two liquid guiding and venting grooves. One of the liquid guiding and venting grooves is set along the length direction parallel to the negative electrode sheet, and the length is 83.9 mm (i.e., 92% a2). The other liquid guiding and venting groove is set along the width direction parallel to the negative electrode sheet, and the length is 65.1 mm (i.e., 92% b2). The two liquid guiding and venting grooves are arranged in a cross shape, and the intersection point is located at the intersection of the two diagonals in the central area of ​​the negative electrode sheet. The two liquid guiding and venting grooves are also symmetrically arranged with respect to the intersection point. Other aspects are the same as the negative electrode sheet in Example 1.

[0140] This comparative example also proposes a battery that differs from the battery of Example 1 in that: the positive and negative electrode plates used in this comparative example are replaced with those used in the battery of Example 1, while the rest is the same as the battery of Example 1. Furthermore, in this comparative example battery, both the positive and negative electrode plates contain liquid-guiding and venting grooves that are perpendicularly intersecting along the length and width directions of the electrode plates and have an electrolyte-affinity conductive coating on their inner walls.

[0141] Comparative Example 7 This comparative example presents a positive electrode sheet that differs from the positive electrode sheet of Example 1 in that: the positive electrode sheet of this comparative example has several liquid-conducting and venting grooves on the positive electrode active material layer, with the longest liquid-conducting and venting groove arranged along a diagonal of the positive electrode active material layer, and the other liquid-conducting and venting grooves arranged parallel to the longest liquid-conducting and venting groove. Adjacent liquid-conducting and venting grooves are evenly spaced (0.5 mm apart), and both ends of each liquid-conducting and venting groove penetrate the edge of the positive electrode active material layer. The width and depth of each liquid-conducting and venting groove on the positive electrode sheet of this comparative example are the same as those on the positive electrode sheet of Example 1; the inner wall surface of the liquid-conducting and venting grooves of this comparative example does not have the electrolyte affinity conductive coating as in Example 1. Everything else is the same as the positive electrode sheet of Example 1.

[0142] This comparative example also proposes a negative electrode sheet, which has a similar structure to the positive electrode sheet in this comparative example. The difference between this negative electrode sheet and the negative electrode sheet of Example 1 is that the negative electrode active material layer of this comparative example has several liquid-conducting and venting grooves. The longest liquid-conducting and venting groove is arranged along a diagonal of the negative electrode active material layer, while the other liquid-conducting and venting grooves are arranged parallel to the longest liquid-conducting and venting groove. Adjacent liquid-conducting and venting grooves are evenly spaced (0.5 mm apart), and both ends of each liquid-conducting and venting groove penetrate the edge of the negative electrode active material layer. The width and depth of each liquid-conducting and venting groove on the negative electrode sheet of this comparative example are the same as those on the negative electrode sheet of Example 1; however, the inner wall surface of the liquid-conducting and venting grooves in this comparative example does not have the electrolyte-affinity conductive coating as in Example 1. Everything else is the same as the negative electrode sheet of Example 1.

[0143] Using the same contact angle testing method as in Example 1, the contact angle θ of the electrolyte affinity conductive coating on the inner wall of the liquid conduction and venting groove on both the positive and negative electrodes in this comparative example was 32° for a 1 mol / L LiPF6 electrolyte (solvents were EC, PC, DEC and PP in a volume ratio of 1.2:1:4:4).

[0144] This comparative example also proposes a battery that differs from the battery of Example 1 in that: the positive electrode and negative electrode of this comparative example are used instead of the positive electrode and negative electrode used in the battery of Example 1, while the rest is the same as the battery of Example 1.

[0145] Performance testing (1) Energy density test Charge the battery at a constant current and constant voltage of 0.05C to 4.55V, with a cutoff voltage of 0.02C; then discharge it at a constant current of 0.2C to 3.0V, and record the capacity C0 and energy W0; the plateau voltage V0 = W0 / C0.

[0146] The battery's half-charge thickness was tested using a 600PPG tester, and the battery's length and width were measured using a thickness gauge. The energy density was then calculated using the formula: "Energy density ED = C0 × V0 / (length × width × thickness) × 1000, in Wh / L".

[0147] (2) Loop testing Cyclic testing was conducted at room temperature. The charge-discharge process employed a multi-stage constant current and constant voltage approach: during the charging phase, the cells were sequentially charged at a constant current of 3C to 4.25V, 2.5C to 4.35V, 2C to 4.4V, and 1.5C to 4.5V, followed by constant voltage charging until the current dropped to 1.2C, then charged at a constant current of 1.2C to 4.55V, and finally charged at a constant voltage until the current dropped to 0.26C. During the discharging phase, the cells were discharged at a constant current of 0.7C until the cutoff voltage of 3.0V. Continuous cyclic testing was performed according to this pattern, and the initial half-cell thickness (T) was recorded. initial ) and initial discharge capacity (C initial ), and the discharge capacity (C) was tested after 800 cycles. 800 ) and cell thickness (T) 800 Finally, the retention rate after 800 cycles is calculated using the formula "800-week cycle retention rate = C". 800 / C initial "×100%" and "800-cycle expansion rate = T" 800 / T initial The 800-cycle capacity retention rate and 800-cycle expansion rate are calculated using the "×100%" formula.

[0148] (3) Immersion time test In preparing the batteries of each embodiment and comparative example, bare cells were first fabricated by stacking positive electrode sheets, separators and negative electrode sheets. Then, the bare cells were immersed in a container full of electrolyte. The time required for different cells to be completely immersed in the electrolyte was compared, and the unit was min.

[0149] (4) Exhaust rate test High-voltage accelerated aging test was conducted, and charge-discharge cycles were performed at 60°C. The rate of gas (CO2, H2) released from the battery cell was monitored by in-situ gas chromatography (GC).

[0150] (5) Low-temperature discharge test The battery is fully charged and then discharged to 3.0V at room temperature to obtain the initial discharge capacity C1. The fully charged battery is then placed in a -10℃ temperature chamber and discharged at a constant current of 1C to 3.0V to obtain the discharge capacity C2 at this temperature. Finally, the low-temperature discharge remaining capacity ratio is calculated according to the formula "low-temperature discharge remaining capacity ratio = C2 / C1".

[0151] (6) Test of the proportion of "X" shaped bright spots The batteries that completed the 800-cycle test were disassembled and analyzed. Specifically, for each embodiment and comparative battery, 10 battery samples were randomly selected. After disassembly, the surface condition of the electrode plates was observed one by one to check for any abnormal bright spots in an "X" shape. The number of batteries exhibiting this bright spot was counted, and this number was divided by the total sample size of 10. The result is the proportion of "X" shaped bright spots, used to quantify the frequency of this phenomenon.

[0152] The performance of the electrodes and corresponding batteries of each embodiment and comparative example were tested according to the above method, and the results are shown in Table 1.

[0153] Table 1

[0154] As shown in Table 1 above, and through Examples 1-18 and Comparative Examples 1-7, the present invention significantly improves the electrolyte wetting effect by setting diagonal liquid-conducting and venting channels on the active material layer of the positive and / or negative electrode sheets, which intersect and extend to the corner areas. The electrolyte can quickly wet towards the center along the liquid-conducting and venting channels, shortening the wetting time. Furthermore, the electrolyte can diffuse laterally from the liquid-conducting and venting channels to both sides of the active layer, greatly improving the uniformity of electrolyte distribution within the electrode sheets. This provides more favorable conditions for electrochemical reactions within the cell, effectively avoiding the problem of insufficient local reactions caused by uneven electrolyte wetting, and greatly reducing the probability of "X"-shaped or "dog bone" shaped bright spot areas. In addition, this channel becomes a "shortcut" for gas to escape to the side. When gas is generated inside the cell, it can quickly escape to the side of the cell through the channel, reducing gas accumulation inside the cell. Due to the improved electrolyte wetting effect and smoother gas venting, the lithium-ion transport path within the electrode is more unobstructed, increasing the effective contact area between the electrode active material and the electrolyte, thus significantly reducing the internal resistance of the cell. Furthermore, by applying an electrolyte-affinity conductive coating to the inner wall of the liquid-conducting and venting channel, the wetting and diffusion rate of the electrolyte within the channel can be further enhanced, while reducing venting resistance and facilitating "wetting-venting counteraction." This electrolyte-affinity conductive coating also possesses good conductivity, high electrolyte wettability, and structural stability, further reducing interfacial impedance, promoting uniform electrochemical reactions, enhancing electrochemical reaction efficiency, improving battery rate performance, and significantly reducing the probability of bright spots while maintaining similar energy densities.

[0155] Furthermore, comparing Examples 1-18 with Comparative Example 1, it can be seen that, compared to the traditional design without diagonal liquid-venting channels, the battery cell of this invention, while ensuring acceptable energy density (ED) loss, effectively reduces the probability of "X"-shaped or "dog bone"-shaped bright spot areas, significantly improving low-temperature discharge performance and cycle performance. This is mainly because the electrolyte can rapidly wet towards the center along the liquid-venting channels, while simultaneously guiding the electrolyte to diffuse laterally from the channels to the active layers on both sides. The channels also become a "shortcut" for gas to escape to the sides, directly alleviating the wetting-venting resistance at the diagonal. The "diagonal liquid-venting channel" design of the electrode, through the synergy of structural innovation and material optimization, fundamentally alleviates the core conflict between electrolyte wetting and gas venting, significantly improving the wettability of the electrolyte on the electrode and greatly reducing the internal resistance of the battery cell.

[0156] Comparing Examples 1 to 5, it can be seen that when the liquid conduction-venting channel is only set on the positive or negative electrode plate, or the number of channels is reduced, the energy density of the cell is improved to a certain extent, but other low-temperature discharge, cycle retention rate and expansion performance are reduced.

[0157] Comparing Examples 1 and 6-9, it can be seen that when the depth h of the liquid guiding and venting groove is within a certain range (i.e., 1 / 5 H < h < 1 / 2 H, where H is the thickness of the active material layer on one side), it has a significant effect on improving the electrolyte wetting effect. When it is below the lower limit or above the upper limit, various properties are affected to varying degrees. If it is too deep, the strength of the electrode structure decreases, and it is prone to breakage; if it is too shallow, the range of electrolyte inflow decreases, and the wetting effect decreases.

[0158] Comparing Examples 1 and 10-13, it can be seen that when the width W of the liquid guiding and venting groove is within a certain range (0.05mm~1mm), it has a significant effect on improving the electrolyte wetting effect. Similarly, when it is below the lower limit or above the upper limit, various performance aspects are affected to varying degrees. A width that is too large may increase the risk of active material detachment from the electrode, while a width that is too small may cause the channel to be easily blocked by electrolyte residue.

[0159] Comparing Examples 1 and 14-17, it can be seen that when the length L of the liquid guiding and venting channel is within a certain range (90%×c / 2≤L≤95%×c / 2, where c is the diagonal length of the active material layer), it has a significant effect on improving the electrolyte wetting effect. Similarly, when it is below the lower limit or above the upper limit, various performance aspects are affected to varying degrees. When the length of the liquid guiding and venting channel is insufficient, the improvement effect on cell performance is reduced, mainly because insufficient length may lead to a wetting blind zone in the center of the electrode.

[0160] Comparing Comparative Example 1 with Examples 1 and 18, it can be seen that when the liquid guiding and venting groove is not coated with a highly wettable conductive paste, although the wetting efficiency decreases, the cell performance still has a great advantage compared to when the liquid guiding and venting groove is not set, and the bright spot improvement effect is obvious.

[0161] Comparing Example 1 and Comparative Examples 4-6, it can be seen that when the electrode is arranged parallel to its width or length, all its performance characteristics are affected. This is mainly because the parallel arrangement cannot significantly improve the contradiction of "the most intense diagonal resistance," and the wetting-venting resistance at the diagonal cannot be effectively alleviated.

[0162] Comparing Example 1 and Comparative Example 7, it can be seen that when channels are arranged parallel to the diagonal, with the number diagonally increasing and the length decreasing, and without being coated with a highly wettable conductive paste, all performance characteristics are affected. This is mainly because unidirectional diagonal channel arrangement leads to an excessive number of channels, resulting in excessive capacity loss, reduced ED (expansion potential), and decreased wetting rate. Simultaneously, during fast charging, gas generation is concentrated at the center of the electrode, and the channels are easily blocked due to excessive local gas generation, making it impossible to effectively alleviate the wetting-gas resistance at the diagonal.

[0163] Therefore, the "diagonal liquid guiding-venting channel" structure of the present invention can significantly shorten the electrolyte wetting time, improve the cycle capacity retention rate, and completely suppress the generation of "X"-shaped / "dog bone" shaped bright spots.

[0164] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An electrode sheet, characterized in that, The device includes a current collector and an active material layer disposed on at least one side surface of the current collector. The active material layer has a central region and a first corner region, a second corner region, a third corner region, and a fourth corner region arranged sequentially along the circumference of the central region. The first corner region and the third corner region are disposed opposite each other, and the second corner region and the fourth corner region are disposed opposite each other. The active material layer has a first liquid guiding and venting groove, a second liquid guiding and venting groove, a third liquid guiding and venting groove, and a fourth liquid guiding and venting groove. One end of the first liquid guiding and venting groove, the second liquid guiding and venting groove, the third liquid guiding and venting groove, and the fourth liquid guiding and venting groove converge and communicate at the central region, and the other end extends to the first corner region, the second corner region, the third corner region, and the fourth corner region, respectively.

2. The electrode sheet according to claim 1, characterized in that, The electrode satisfies at least one of the following conditions: Condition A1: There is a gap between the end of the first liquid-guiding and venting groove located in the first corner region and the edge of the active material layer; Condition A2: There is a gap between the end of the second liquid-guiding and venting groove located in the second corner region and the edge of the active material layer; Condition A3: There is a gap between the end of the third liquid guiding and venting groove located in the third corner region and the edge of the active material layer; Condition A4: There is a gap between the end of the fourth liquid-guiding and venting groove located in the fourth corner region and the edge of the active material layer.

3. The electrode sheet according to claim 2, characterized in that, The active material layer has a first diagonal and a second diagonal that intersect, the first diagonal connecting the diagonal between the first corner region and the third corner region, and the second diagonal connecting the diagonal between the second corner region and the fourth corner region, the first diagonal and the second diagonal intersecting at the central region; the electrode satisfies at least one of the following conditions: Condition B1: The absolute value of the angle between the extension direction of the first liquid guiding and venting groove and the first diagonal is 0°~15°; Condition B2: The absolute value of the angle between the extension direction of the third liquid guiding and venting groove and the first diagonal is 0°~15°; Condition B3: The absolute value of the angle between the extension direction of the second liquid guiding and venting groove and the second diagonal is 0°~15°; Condition B4: The absolute value of the angle between the extension direction of the fourth liquid guiding and venting groove and the second diagonal is 0°~15°.

4. The electrode sheet according to claim 1, characterized in that, At least one of the following conditions must be met: Condition C1: The width W of at least one of the first liquid guiding and venting groove, the second liquid guiding and venting groove, the third liquid guiding and venting groove, and the fourth liquid guiding and venting groove satisfies: 0.05mm≤W≤1mm; Condition C2: The length of the active material layer is a, the width is b, and the diagonal length c of the active material layer is... The length L of at least one of the first liquid guiding and venting groove, the second liquid guiding and venting groove, the third liquid guiding and venting groove, and the fourth liquid guiding and venting groove satisfies: 90%×c / 2≤L≤95%×c / 2; Condition C3: The thickness of one side of the active material layer is H, and the depth h of at least one of the first liquid guiding and venting groove, the second liquid guiding and venting groove, the third liquid guiding and venting groove and the fourth liquid guiding and venting groove satisfies: 1 / 5 H < h < 1 / 2 H.

5. The electrode sheet according to any one of claims 1 to 4, characterized in that, At least one of the first liquid-conducting venting groove, the second liquid-conducting venting groove, the third liquid-conducting venting groove, and the fourth liquid-conducting venting groove has an electrolyte-affinity conductive coating on its inner wall surface.

6. The electrode sheet according to claim 5, characterized in that, The electrolyte-affinity conductive coating satisfies at least one of the following conditions: Condition D1: The electrolyte-affinity conductive coating comprises an electrolyte-affinity material, a conductive filler, and a binder; preferably, the electrolyte-affinity material comprises surface-modified nano-SiO2, wherein the surface-modified nano-SiO2 is nano-SiO2 with electrolyte-affinity groups grafted onto its surface; Condition D2: The contact angle of the electrolyte on the surface of the electrolyte-affinity conductive coating is less than 15°; Condition D3: The conductivity of the electrolyte-affinity conductive coating is 10. -3 S / cm or higher.

7. A method for preparing the electrode sheet according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. An active material layer is constructed on at least one side surface of the current collector; the active material layer has a central region and a first corner region, a second corner region, a third corner region and a fourth corner region arranged sequentially along the circumference of the central region; the first corner region and the third corner region are arranged opposite to each other, and the second corner region and the fourth corner region are arranged opposite to each other; S2. A first liquid-guiding and venting groove, a second liquid-guiding and venting groove, a third liquid-guiding and venting groove, and a fourth liquid-guiding and venting groove are formed on the active material layer; one end of the first liquid-guiding and venting groove, the second liquid-guiding and venting groove, the third liquid-guiding and venting groove, and the fourth liquid-guiding and venting groove converge and connect in the central region, and the other end extends to the first corner region, the second corner region, the third corner region, and the fourth corner region, respectively.

8. The method for preparing the electrode according to claim 7, characterized in that, Also includes: Step S3: An electrolyte-affinity conductive coating is provided on the inner wall surface of at least one of the first liquid-conducting venting groove, the second liquid-conducting venting groove, the third liquid-conducting venting groove, and the fourth liquid-conducting venting groove; Preferably, step S3 specifically includes: preparing an electrolyte-affinity conductive slurry by mixing raw materials including an electrolyte-affinity material, a conductive filler, and a binder with a solvent; then coating the inner wall of at least one of the first liquid-conducting venting groove, the second liquid-conducting venting groove, the third liquid-conducting venting groove, and the fourth liquid-conducting venting groove with the electrolyte-affinity conductive slurry; and drying to form an electrolyte-affinity conductive coating.

9. A battery, characterized in that, The electrode includes the electrode prepared by any one of claims 1 to 6 or the electrode prepared by any one of claims 7 to 8.

10. An electrical appliance, characterized in that, Includes the battery as described in claim 9.

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