Negative plate, positive plate, pole core, battery and carrier

Abstract

The invention relates to the field of batteries, and discloses a negative plate, a positive plate, a pole core, a battery and a carrier. The negative plate comprises a main body part which is used for being overlapped with the positive plate, and a first permeation hole is formed in the position, at least close to the edge, of the surface of the main body part; the suspended part is connected to the outer side of the edge of the main body part and exceeds the edge of the positive plate, and second permeation holes are formed in the surface of the suspended part; wherein the depth of at least one of the first permeation hole and the second permeation hole is the product of the weighted square sum of the maximum charging rate and the maximum discharging rate after square extraction and the thickness and the proportionality coefficient of the negative electrode active material layer. The first permeation holes and the second permeation holes can provide more channels for the electrolyte to enter the negative plate, especially in an overhang area, so that lithium ions can be supported by the electrolyte more timely in the migration process, and the problem that lithium ions are gathered and separated due to the fact that the migration of the lithium ions is limited due to insufficient electrolyte is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a negative electrode sheet, a positive electrode sheet, a cell core, a battery and a vehicle. Background Art

[0002] As an energy storage device, the charging speed of a battery is one of the key factors affecting the user experience. To meet people's demand for fast charging, high-rate charging technology has emerged and developed rapidly.

[0003] During high-rate charging, lithium ions rapidly migrate from the positive electrode to the negative electrode under the action of the electric field force. However, in the overhang region (i.e., the region where the edge of the negative electrode sheet protrudes relative to the edge of the positive electrode sheet), due to its unique position characteristics, the diffusion and migration path of lithium ions becomes complex, and the migration resistance increases. This makes it difficult to evenly distribute lithium ions in the overhang region, resulting in too high a concentration of lithium ions in some regions and prone to the problem of lithium deposition at the edge of the electrode sheet.

[0004] Lithium deposition not only consumes the lithium resources inside the battery, leading to a decrease in battery capacity, but also forms lithium dendrites on the surface of the electrode sheet. The growth of lithium dendrites may pierce the separator, causing an internal short circuit of the battery. Summary of the Invention

[0005] In view of this, the present invention provides a negative electrode sheet, a positive electrode sheet, a cell core, a battery and a vehicle to solve or improve the problem of easy lithium deposition at the edge of the electrode sheet.

[0006] In a first aspect, the present invention provides a negative electrode sheet for a battery, comprising:

[0007] A main body portion for being stacked and coincided with the positive electrode sheet, and at least a position near the edge on the surface of the main body portion is provided with a first penetration hole;

[0008] An overhang portion connected to the outside of the edge of the main body portion and exceeding the edge of the positive electrode sheet, and the surface of the overhang portion is provided with a second penetration hole;

[0009] Wherein, at least one of the first penetration hole and the second penetration hole has a depth of H1;

[0010]

[0011] Wherein, α is a proportionality coefficient, H2 is the thickness of a single-layer negative electrode active material layer, C1 is the maximum charging rate of the battery, C2 is the maximum discharging rate of the battery, and w1 and w2 are both weighting coefficients.

[0012] In an optional embodiment, the value range of α is 0.05 to 0.9;

[0013] And / or, w1 is greater than or less than w2.

[0014] In an alternative embodiment, the pore diameter of at least one of the first permeation holes and the second permeation holes is R1;

[0015]

[0016] Where ε1 is a proportionality coefficient, D100, D90, D50, and D10 are all particle size distribution parameter values of the particles in the negative electrode active material layer of the negative electrode sheet, and t is a positive number less than 1.

[0017] In an alternative embodiment, the total pore area S1 of the first permeation holes of the main body portion and the surface area S3 of the punching area of the negative electrode sheet satisfy: 1 / 4 * S3 ≤ S1;

[0018] And / or, the total pore area S2 of the second permeation holes of the suspended portion and the surface area S3 of the punching area of the negative electrode sheet satisfy: 1 / 5 * S3 ≤ S2.

[0019] In a second aspect, the present invention further provides a positive electrode sheet for being stacked and coincided with the main body portion of the negative electrode sheet of the battery, and at least a position near the edge of the surface of the positive electrode sheet is provided with a third permeation hole;

[0020] Wherein, the depth of the third permeation hole is H1;

[0021]

[0022] Where α is a proportionality coefficient, H2 is the thickness of a single layer of positive electrode active material layer, C1 is the maximum charge rate of the battery, C2 is the maximum discharge rate of the battery, and w1 and w2 are both weighting coefficients.

[0023] In an alternative embodiment, the value range of α is 0.05 to 0.8;

[0024] And / or, w1 is greater than or less than w2.

[0025] In an alternative embodiment, the pore diameter of the third permeation hole is R1;

[0026]

[0027] Where ε1 is a proportionality coefficient, D100, D90, D50, and D10 are all particle size distribution parameter values of the particles in the positive electrode active material layer of the positive electrode sheet, and t is a positive number less than 1.

[0028] In an alternative embodiment, the total pore area S4 of the third permeation holes and the surface area S5 of the punching area of the positive electrode sheet satisfy: 1 / 8 * S5 ≤ S4.

[0029] In a third aspect, the present invention also provides an electrode core, which includes the negative electrode sheet and / or the positive electrode sheet as described above.

[0030] In a fourth aspect, the present invention also provides a battery, which includes the electrode core as described above.

[0031] In a fifth aspect, the present invention also provides a vehicle, which includes the electrode core or the battery as described above.

[0032] For the negative electrode sheet provided by the present invention, the first penetration holes and the second penetration holes can provide more channels for the electrolyte to enter the interior of the negative electrode sheet, especially in the overhang area, so that lithium ions can obtain the support of the electrolyte more timely during the migration process, reducing the problem of lithium deposition due to the limitation of lithium ion migration caused by insufficient electrolyte. In addition, the penetration holes can accommodate the electrolyte and promote the convection and diffusion of the electrolyte, accelerating the transmission speed of lithium ions in the electrode material, enabling them to disperse to the entire surface of the negative electrode sheet faster and avoiding excessive local concentration. Description of the Drawings

[0033] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0034] Figure 1 It is a schematic structural diagram of the positive electrode sheet projected onto the negative electrode sheet provided in the embodiment of the present invention;

[0035] Figure 2 It is a schematic structural diagram of the negative electrode sheet provided in the embodiment of the present invention;

[0036] Figure 3 It is a schematic structural diagram of the positive electrode sheet provided in the embodiment of the present invention;

[0037] Figure 4 It is a graph of the fast charge cycle capacity retention rate provided in the embodiment of the present invention;

[0038] Figure 5 It is another graph of the fast charge cycle capacity retention rate provided in the embodiment of the present invention.

[0039] Description of the Reference Numerals:

[0040] 1. Negative electrode sheet; 101. Main body part; 102. Overhang part; 103. First penetration hole; 104. Second penetration hole; 105. Negative electrode current collector; 106. Negative electrode active material layer; 107. Main body punching area; 108. Negative electrode tab; 2. Positive electrode sheet; 201. Third penetration hole; 202. Positive electrode current collector; 203. Positive electrode active material layer; 204. Positive electrode punching area; 205. Positive electrode tab. Detailed implementation manners

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] In existing lithium-ion batteries, when undergoing high-rate charging, lithium ions rapidly migrate from the positive electrode to the negative electrode under the action of the electric field force. However, in the overhang region (i.e., the region where the edge of the negative electrode sheet protrudes relative to the edge of the positive electrode sheet), due to its unique position characteristics, the diffusion and migration path of lithium ions becomes complex, and the migration resistance increases. This makes it difficult to evenly distribute lithium ions in the overhang region, resulting in too high a concentration of lithium ions in some regions and prone to the problem of lithium deposition at the edge of the electrode sheet.

[0043] Lithium deposition not only consumes the lithium resources inside the battery, leading to a decrease in battery capacity, but also forms lithium dendrites on the surface of the electrode sheet. The growth of lithium dendrites may pierce the separator, causing an internal short circuit in the battery.

[0044] To solve or improve the problem of easy lithium deposition at the edge of the electrode sheet, the present invention provides a negative electrode sheet, a positive electrode sheet, a pole core, a battery, and a vehicle.

[0045] The following combines Figures 1 to 5 , to describe the negative electrode sheet 1 provided in the embodiments of the present invention.

[0046] Specifically, the negative electrode sheet 1 includes a main body part 101 and an overhang part 102.

[0047] Among them, the main body part 101 is used to overlap and coincide with the positive electrode sheet 2. Or, it can be said that the length dimension of the main body part 101 is equal to the length dimension of the positive electrode sheet 2, and the width dimension of the main body part 101 is equal to the width dimension of the positive electrode sheet 2. For example, as shown in Figure 1 , when the positive electrode sheet 2 is projected onto the surface of the negative electrode sheet 1, the edge of the positive electrode sheet 2 forms a frame A on the surface of the negative electrode sheet 1, and the edge of the frame A coincides with the edge of the main body part 101.

[0048] Further, at least at a position near the edge on the surface of the main body portion 101, a first penetration hole 103 is provided, that is, at least at a position near the frame body A on the surface of the main body portion 101. For example, the number of the first penetration holes 103 can be multiple.

[0049] The overhanging portion 102 is connected to the outer side of the edge of the main body portion 101 and extends beyond the edge of the positive electrode sheet 2, that is, the overhanging portion 102 serves as the overhang region of the negative electrode sheet 1 and can extend beyond the boundary of the positive electrode sheet 2. Optionally, the overhanging portion 102 and the main body portion 101 are of an integral structure. Optionally, the overhanging portion 102 is arranged along the edge of the main body portion 101 in at least one direction, such as Figure 1 and Figure 2 As shown, an example of the overhanging portion 102 arranged along the four edges of the main body portion 101 is shown. The surface of the overhanging portion 102 is provided with a second penetration hole 104.

[0050] It can be understood that both the main body portion 101 and the overhanging portion 102 have a negative current collector 105 and a negative active material layer 106 provided on the surface of the negative current collector 105, and the negative current collectors 105 of the main body portion 101 and the overhanging portion 102 can have the same thickness and be of an integral structure, and the negative active material layers 106 of the main body portion 101 and the overhanging portion 102 can have the same thickness and be of an integral structure.

[0051] Wherein, the depth of at least one of the first penetration hole 103 and the second penetration hole 104 is determined based on at least one of the maximum charge rate and the maximum discharge rate of the battery, and the thickness of the negative active material layer 106 on one side of the negative electrode sheet 1. The maximum discharge rate of the battery refers to the ratio of the maximum current value at which the battery can safely and continuously discharge to its rated capacity, and the maximum charge rate of the battery refers to the ratio of the maximum current intensity that the battery can accept during charging to its rated capacity.

[0052] For example, at least within a certain range, the depth of at least one of the first penetration hole 103 and the second penetration hole 104 is positively correlated with at least one of the maximum charge rate and the maximum discharge rate and the thickness of the negative active material layer 106 on one side.

[0053] In this embodiment, the first penetration hole 103 and the second penetration hole 104 can provide more channels for the electrolyte to enter the inside of the negative electrode sheet 1, especially in the overhang region, so that lithium ions can obtain the support of the electrolyte more timely during the migration process, reducing the problem of lithium deposition due to the limitation of lithium ion migration caused by insufficient electrolyte.

[0054] In addition, the penetration holes can accommodate the electrolyte and can promote the convection and diffusion of the electrolyte, accelerating the transmission speed of lithium ions in the electrode material, enabling them to be dispersed on the entire surface of the negative electrode sheet 1 faster, and avoiding local over-concentration.

[0055] The position of the first penetration holes 103 near the edge of the main body 101 can guide lithium ions to migrate into the main body 101, rather than accumulating excessively in the overhang area, thereby alleviating the lithium ion accumulation situation in the overhang area caused by the complex lithium ion migration path and large resistance, and making the lithium ion distribution more uniform.

[0056] The second penetration holes 104 of the overhang 102 provide a direct diffusion channel for lithium ions in view of the special environment of the overhang area, making it easier for lithium ions to penetrate the negative active material layer 106, reducing the lithium ion migration resistance in this area, and further reducing the occurrence probability of lithium deposition.

[0057] Determining the depth of the penetration holes according to the maximum charge rate and the maximum discharge rate of the battery can accurately control the migration rate and distribution of lithium ions in the negative electrode sheet 1.

[0058] For example, during high-rate charge and discharge, appropriately deepen the depth of the penetration holes and increase the penetration amount of the electrolyte to cope with the rapidly migrating lithium ions and prevent lithium deposition due to their inability to diffuse in time.

[0059] In the case of low-rate charge and discharge, reasonably reduce the depth of the penetration holes to avoid other problems caused by excessive penetration. For example, if the penetration holes are too deep, the electrolyte may more easily penetrate into the negative electrode sheet 1. At low rates, the internal reaction of the battery is relatively slow, and the excessive penetration of the electrolyte may lead to too high a local concentration of the electrolyte in the negative electrode sheet 1, accelerating the decomposition reaction of the electrolyte and causing excessive consumption of the electrolyte.

[0060] The thickness of the negative active material layer 106 is also one of the factors for determining the depth of the penetration holes, which helps to ensure that in negative electrode sheets 1 with different thicknesses, lithium ions can migrate uniformly at a suitable concentration gradient, reducing the lithium deposition phenomenon caused by too large a concentration difference.

[0061] Furthermore, a negative active material layer 106 is provided on one side of the negative current collector 105, and the negative active material layer 106 is provided with the first penetration holes 103 and the second penetration holes 104. Or negative active material layers 106 are provided on both sides of the negative current collector 105, and at least one side of the negative active material layer 106 is provided with the first penetration holes 103 and the second penetration holes 104.

[0062] It can be understood that for each side of the negative active material layer 106, the depth of the first penetration holes 103 or the second penetration holes 104 is determined based on the thickness of the negative active material layer 106 where they are located.

[0063] In some embodiments provided by the present invention, the depth of at least one of the first penetration holes 103 and the second penetration holes 104 is determined based on the weighted sum of squares of the maximum charging rate and the maximum discharging rate, and the thickness of the negative electrode active material layer 106 on one side of the negative electrode.

[0064] The maximum charging rate and the maximum discharging rate reflect the extreme current demands of the battery under different operating scenarios. In this embodiment, by incorporating the weighted sum of squares of the two into the basis for determining the depth, it is possible to comprehensively consider the lithium-ion migration requirements of the battery under different operating conditions such as fast charging and fast discharging, making the depth of the penetration holes match the current changes in the actual operation of the battery, ensuring that lithium ions have a suitable channel and migration environment during charging or discharging conditions, and improving the overall performance and efficiency of the battery.

[0065] For example, for some electric vehicle batteries that need to be charged in a short time and have high power output capabilities, this design method can ensure that the depth of the penetration holes in the negative electrode sheet 1 is accurately matched with the high-rate charge and discharge requirements of the battery, thereby optimizing the performance of the battery.

[0066] Compared with the design method that only considers a single factor (such as only considering the charging rate or the discharging rate), this design based on the weighted sum of squares can more accurately reflect the comprehensive requirements of the battery in actual use, avoiding performance imbalance caused by only focusing on one aspect.

[0067] In addition, a thicker active material layer means that lithium ions need to travel a longer distance to reach the current collector, which will increase the migration resistance of lithium ions. By correlating the depth of the penetration holes with the thickness of the active material layer, the depth of the penetration holes can be adjusted according to the thickness of the active material layer of different thicknesses to ensure that the penetration of the electrolyte and the migration of lithium ions can be effectively guaranteed in the entire thickness direction of the negative electrode sheet 1.

[0068] In summary, comprehensively considering the charge and discharge rates and the thickness of the active material layer to determine the depth of the penetration holes can more accurately optimize the distribution and migration of lithium ions on the negative electrode sheet 1. During high-rate charge and discharge, it can effectively reduce the situation of excessive lithium-ion concentration in positions such as the overhang area, reduce the occurrence of lithium deposition phenomenon, reduce the risk of lithium dendrite growth and internal short circuit of the battery, and improve the safety of the battery.

[0069] In some embodiments provided by the present invention, the depth of at least one of the first penetration holes 103 and the second penetration holes 104, the maximum charging rate, the maximum discharging rate, and the thickness of the negative electrode active material layer 106 satisfy:

[0070]

[0071] Among them, H1 is the depth of the first penetration hole 103 or the depth of the second penetration hole 104, and its unit is μm. H2 is the thickness of the single-layer negative electrode active material layer 106, and its unit is μm.

[0072] α is a proportionality coefficient, and α can be a coefficient related to the intrinsic properties of the negative electrode active material. Its value ranges from 0.05 to 0.9. For example, the value of α can be 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, or 0.9.

[0073] C1 is the maximum charging rate, and C2 is the maximum discharging rate.

[0074] Both w1 and w2 are weighting coefficients.

[0075] In this embodiment, by introducing the weighting coefficients w1 and w1, the formula can achieve flexible adaptation to the charge and discharge scenarios.

[0076] For example, increasing w1, or making w1 greater than w2, for example, w1 is 0.8 and w2 is 0.125. In this way, the influence of the maximum charging rate C1 on the penetration hole depth can be strengthened, and the lithium-ion migration path during high-rate charging can be shortened. For example, it can be applied to occasions that require fast charging.

[0077] For example, increasing w2, or making w1 less than w2, then optimizing the weight of the maximum discharging rate C2 on the penetration hole depth to ensure that the electrolyte is fully infiltrated during high-rate discharging and suppress lithium plating.

[0078] Regarding α in the formula, it is directly related to the intrinsic properties of the negative electrode material, which can make the design of the penetration hole depth more in line with the material performance and give full play to the material advantages. For example, optionally, for a negative electrode material with a high porosity (such as a silicon-based negative electrode), α can be increased accordingly to supplement its low conductivity through deep holes; for a dense material (such as graphite), α can be decreased accordingly to avoid excessive damage to the structural stability.

[0079] Of course, the quantitative relationship between α and different material properties can also be established through a large number of experiments and data analyses to achieve a more precise design of the penetration hole depth.

[0080] In some embodiments provided by the present invention, the pore diameter of at least one of the first penetration hole 103 and the second penetration hole 104 is determined based on the particle size of the particles in the negative electrode active material layer 106 of the negative electrode sheet 1. For example, at least one of the first penetration hole 103 and the second penetration hole 104 is a round hole, and the pore diameter of the round hole is determined based on the particle size of the particles in the negative electrode active material layer 106 of the negative electrode sheet 1.

[0081] The particle size in the negative electrode active material layer 106 affects the lithium ion transmission path. In this embodiment, the pore size is determined according to the particle size, which can make the size of the penetration pores adapt to the diffusion of lithium ions between the particles, reduce the resistance during lithium ion diffusion, facilitate the smooth migration of lithium ions, and improve the charge and discharge efficiency of the battery.

[0082] In addition, the adaptation of the pore size to the particle size helps to improve the wettability of the electrolyte to the negative electrode material. Good wettability can ensure that the electrolyte can fully contact each active material particle, thereby enhancing the overall performance of the battery.

[0083] A suitable pore size avoids excessive damage to the structure of the negative electrode sheet 1. If the pore size is too large, the binding force between the active material and the current collector will be weakened; if it is too small, the effect of promoting ion transmission cannot be achieved. Determining the pore size based on the particle size can improve the performance while maintaining the structural stability of the electrode and extending the battery life.

[0084] In some embodiments provided by the present invention, the pore size of at least one of the first penetration pores 103 and the second penetration pores 104 is determined based on the decimal power of D100, and the difference between D90 and D10 divided by D50. Or rather, the pore size of the round hole is determined based on the decimal power of D100, and the difference between D90 and D10 divided by D50.

[0085] Among them, D100, D90, D50, and D10 are all particle size distribution parameter values of the particles in the negative electrode active material layer 106 of the negative electrode sheet 1. For example, D90 means that 90% of the particles in the sample have a particle size smaller than this value.

[0086] In this embodiment, setting the decimal power of D100 can not only consider the limitation of the pore size by the local feature of the largest particle size particles, but also through the decimal power operation, on the basis of considering the influence of large particles, reduce the excessive influence of the largest particle size particles on the pore size, that is, avoid the problem of too large pore size caused by directly using D100, so as to optimize the limiting effect on large particles.

[0087] In addition, by dividing the difference between D90 and D10 by D50, the difference between D90 and D10 can intuitively represent the span range from the smaller particle size part to the larger particle size part in the particle size distribution. Dividing the difference between D90 and D10 by D50 is to compare this span with the average particle size of the particles to achieve normalization processing, so as to evaluate the uniformity of the particle size and ensure that the obtained pore size is closer to the characteristics of the actual material.

[0088] In summary, by adjusting the pore size of the penetration pores with these parameters, the actual distribution of the particle size and the uniformity of the particle size in the negative electrode active material layer 106 can be more accurately reflected, ensuring that the designed pore size is more in line with the characteristics of the actual material.

[0089] In some embodiments provided by the present invention, the pore diameter of at least one of the first penetration holes 103 and the second penetration holes 104 is based on:

[0090] Determined.

[0091] Wherein, R1 is the diameter of the first penetration hole 103 or the second penetration hole 104, and its unit is μm.

[0092] ε1 is a proportionality coefficient. For example, it is a coefficient related to the negative electrode design, and its value is between 0.1 and 10. For example, the value of ε1 is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 or 10.

[0093] t is a positive number less than 1. For example, t is 2 / 3, and it can also be 1 / 2 or 3 / 4.

[0094] In this embodiment, based on the above formula calculation and control, wherein, (D100) t It can ensure that the pore diameter can adapt to the largest particles, but will not cause the pore diameter to be too large due to individual large particles. By adjusting t, the relationship between the pore diameter and the maximum particle size can be balanced. For example, reducing the value of t can inhibit the growth rate of the pore diameter with D100, which is applicable to scenarios with high mechanical strength requirements. Increasing the value of t can enhance the pore diameter adaptability to large particles, which is applicable to easily blocked materials.

[0095] The particle size distribution width can be quantified. When the distribution is wide, the pore diameter is automatically increased to ensure sufficient penetration of the electrolyte in complex gaps.

[0096] By setting ε1, from the perspective of the negative electrode design, it can be flexibly adjusted according to the actual electrode structure, process, etc., so that the pore diameter design can better meet the overall electrode design requirements, providing flexibility across materials and processes. For example, for a high-porosity electrode, ε1 can be reduced. For example, ε1 is 0.5 to avoid excessive damage to the structure. For a dense electrode, ε1 can be increased. For example, ε1 is 5 to force open the ion channels.

[0097] Of course, a quantitative relationship between ε1 and the positive electrode can also be established through a large number of experiments and data analyses to achieve a more accurate design of the penetration hole depth.

[0098] In some embodiments provided by the present invention, the total pore area S1 of the first penetration holes 103 of the main body 101 and the surface area S3 of the punching area of the negative electrode sheet 1 satisfy: 1 / 4 * S3 ≤ S1.

[0099] And / or, the total orifice area S2 of the second penetration holes 104 of the overhang portion 102 and the surface area S3 of the punched area of the negative electrode sheet 1 satisfy: 1 / 5 * S3 ≤ S2.

[0100] For example, the surface area S3 of the punched area of the negative electrode sheet 1 is the sum of the area of the main punched area 107 and the area of the overhang portion 102. The total orifice area S1 of the first penetration holes 103 is the sum of the orifice areas of all the first penetration holes 103. Similarly, the total orifice area S2 of the second penetration holes 104 is the sum of the orifice areas of all the second penetration holes 104.

[0101] In this embodiment, 1 / 4 * S3 ≤ S1 can ensure that the main body portion 101 has sufficient penetration hole area, shorten the diffusion path of lithium ions, and maximize the ion channel density.

[0102] The high current density in the Overhang area requires more sufficient electrolyte penetration. By setting 1 / 5 * S3 ≤ S2 as the lower limit, local concentration polarization can be inhibited and the risk of lithium deposition can be reduced.

[0103] In summary, specifying the minimum ratio of the total orifice area can ensure sufficient space for the electrolyte to penetrate into the electrode interior, construct an efficient lithium ion transmission channel, and reduce the migration resistance of lithium ions in the electrode. Specifying the total orifice areas of the main body portion 101 and the overhang portion 102 respectively can meet the lithium ion transmission and structural requirements of different regions.

[0104] Optionally, the value of S1 is 1 / 4S3, 1 / 3S3, 1 / 2S3, 2 / 3S3, 3 / 4S3 or 4 / 5S3. Optionally, the value of S2 is 1 / 5S3, 1 / 4S3, 1 / 3S3, 1 / 2S3, 2 / 3S3, 3 / 4S3 or 4 / 5S3.

[0105] Optionally, both the first penetration holes 103 and the second penetration holes 104 are set as polygonal holes, and further satisfy at least one of 1 / 4 * S3 ≤ S1 and 1 / 5 * S3 ≤ S2.

[0106] In this embodiment, the edge angle design of the polygonal holes (such as triangles, hexagons, squares) can evenly disperse the stress in multiple directions, reducing local stress concentration compared to circular holes. In addition, the side-angle structure of the polygon forms a natural support framework, improving the overall compressive strength of the electrode. Moreover, the sharp edges at the sharp corners of the polygonal holes can enhance the capillary force of the electrolyte and promote rapid wetting.

[0107] Reference Figure 2As shown, in some embodiments provided by the present invention, the suspension part 102 is arranged along the four peripheral edges of the main body part 101, that is, the suspension part 102 forms an annular region. Specifically, the suspension part 102 has four strip-shaped regions. For example, in the X direction, there are two strip-shaped regions extending along the Z direction, and in the Z direction, there are two strip-shaped regions extending along the X direction. The negative electrode tab 108 of the negative electrode sheet 1 protrudes along the X direction.

[0108] In this embodiment, the annular suspension part 102 can disperse the edge electric field intensity, reduce the local current density, and thus significantly reduce the risk of lithium plating.

[0109] Optionally, referring to Figure 2 As shown, assuming that along the X direction, the width of at least one side of the suspension part 102 is L1, then the value range of L1 is 0.2 mm to 5 mm. For example, the value of L1 is 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm. Preferably, the value range of L1 is 1 mm to 4 mm. As Figure 2 shown, an example is that the widths of both sides of the suspension part 102 in the X direction are L1.

[0110] In this embodiment, the suspension part 102 can have a suitable width in the X direction, which is beneficial to improving the lithium ion migration in this area. For example, to avoid too small a width, the ion migration path is restricted, and uneven distribution is prone to lithium plating; also prevent too large a width, resulting in waste of active materials and long ion migration distance, affecting the charge and discharge efficiency of the battery.

[0111] Optionally, referring to Figure 2 As shown, assuming that along the Z direction, the width of at least one side of the suspension part 102 is D1, then the value range of D1 is 0.2 mm to 5 mm. For example, the value of D1 is 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm. Preferably, the value range of D1 is 1 mm to 4 mm. As Figure 2 shown, an example is that the widths of both sides of the suspension part 102 in the Z direction are D1.

[0112] In this embodiment, the suspension part 102 can have a suitable width in the Z direction, which is beneficial to improving the lithium ion migration in this area. For example, to avoid too small a width, the ion migration path is restricted, and uneven distribution is prone to lithium plating; also prevent too large a width, resulting in waste of active materials and long ion migration distance, affecting the charge and discharge efficiency of the battery.

[0113] In some embodiments provided by the present invention, first penetration holes 103 are provided at the edges around the main body portion 101, that is, the main body punching area 107 of the main body portion 101 is an annular area. For example, if a frame B is made within a frame A, the area between the frame A and the frame B is the main body punching area 107.

[0114] In this embodiment, a continuous ion channel can be formed around the main body portion 101, significantly reducing the current density concentration phenomenon in the edge area. The main body punching area 107 covers the junction of the main reaction area and the overhanging portion 102, making it easier for lithium ions on the overhanging portion 102 to diffuse into the main body portion 101 and reducing concentration polarization. In addition, dense channels can be formed at the electrode edge to preferentially guide the electrolyte to infiltrate the edge area with high current density.

[0115] In addition, while ensuring ion transport, the annular punching area will not overly damage the structural integrity of the middle area of the main body portion 101. The middle area can maintain sufficient strength to support the connection between the active material and the current collector, preventing the shedding of the active material or damage to the electrode structure caused by large-area opening, thereby maintaining the stability and reliability of the battery during long-term use.

[0116] Optionally, assuming along the Z direction, the width of at least one side of the main body punching area 107 is D2, and the size of the negative electrode sheet 1 is D, then the ratio range of D2 to D is 1:500 to 1:2. For example, the ratio of D2 to D is 1:500, 1:400, 1:300, 1:200, 1:100, 1:90, 1:80, 1:70, 1:60, 1:50, 1:40, 1:30, 1:20, 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3 or 1:2. Preferably, the ratio range of D2 to D is 1:80 to 1:5. For example Figure 2 It represents an example where the widths of both sides of the main body punching area 107 are D2 in the Z direction.

[0117] In this embodiment, it can be ensured that the width of the punching area can not only shorten the lithium ion migration path but also avoid overly sacrificing the active material area.

[0118] For example, for a battery with high rate requirements, a larger ratio can be selected to strengthen the ion transport ability. For example, the ratio range of D2 to D is 1:20 to 1:5. For a battery with long life requirements, a smaller ratio can be selected to maintain a high energy density. For example, the ratio range of D2 to D is 1:80 to 1:20.

[0119] Optionally, assuming that along the X direction, the width of at least one side of the main body punching area 107 is L2, and the size of the negative electrode sheet 1 is L (excluding the tab), then the ratio range of L2 to L is 1:500 to 1:2. For example, the ratio of L2 to L is 1:500, 1:400, 1:300, 1:200, 1:100, 1:90, 1:80, 1:70, 1:60, 1:50, 1:40, 1:30, 1:20, 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3 or 1:2. Preferably, the ratio range of L2 to L is 1:80 to 1:20. For example Figure 2 This represents an example where the widths of both sides of the main body punching area 107 are L2 in the X direction.

[0120] In this embodiment, it can be ensured that the width of the punching area can not only shorten the lithium ion migration path but also avoid excessive sacrifice of the active material area.

[0121] For example, for a battery with high rate requirements, a larger ratio can be selected to enhance the ion transport ability. For example, the ratio range of L2 to L is 1:40 to 1:20. For a battery with long life requirements, a smaller ratio can be selected to maintain a high energy density. For example, the ratio range of L2 to L is 1:80 to 1:40.

[0122] In an embodiment of the present invention, a positive electrode sheet 2 is also provided.

[0123] Specifically, the positive electrode sheet 2 is used to be stacked and coincided with the main body portion 101 of the negative electrode sheet 1 of the battery. Or, it can be said that the length dimension of the main body portion 101 is equal to the length dimension of the positive electrode sheet 2, and the width dimension of the main body portion 101 is equal to the width dimension of the positive electrode sheet 2. Corresponding to the negative tab 108 of the negative electrode sheet 1, the positive tab 205 of the positive electrode sheet 2 protrudes along the X direction. At least near the edge position on the surface of the positive electrode sheet 2, a third penetration hole 201 is provided. The number of the third penetration holes 201 can be multiple.

[0124] It can be understood that the positive electrode sheet 2 includes a positive current collector 202 and a positive active material layer 203 provided on the surface of the positive current collector 202.

[0125] Among them, the depth of the third penetration hole 201 is determined based on at least one of the maximum charge rate and the maximum discharge rate of the battery, and the thickness of the positive active material layer 203 on one side of the positive electrode sheet 2.

[0126] In this embodiment, the provision of the third penetration holes 201 significantly shortens the migration path of lithium ions within the positive electrode sheet 2. During the charging and discharging processes, lithium ions can migrate more rapidly through these penetration holes between the positive electrode active material layer 203 and the electrolyte, thereby accelerating the charging and discharging speed of the battery, improving the power performance of the battery, and meeting the fast charging and discharging requirements of the device under high power demands.

[0127] The penetration holes can accommodate the electrolyte, and the presence of the penetration holes is conducive to better wetting of the positive electrode sheet 2 by the electrolyte. This not only helps to increase the initial capacity of the battery because more active materials can participate in the reaction, but also can maintain a high capacity retention rate during the long-term use of the battery.

[0128] Determining the depth of the penetration holes according to the maximum charging rate and the maximum discharging rate of the battery can accurately control the migration rate and distribution of lithium ions within the positive electrode sheet 2.

[0129] For example, during high-rate charging and discharging, appropriately deepen the depth of the penetration holes to increase the penetration amount of the electrolyte to cope with the rapidly migrating lithium ions and prevent lithium deposition due to insufficient diffusion time.

[0130] In the case of low-rate charging and discharging, reasonably reduce the depth of the penetration holes to avoid other problems caused by excessive penetration and maintain the structural stability of the positive electrode active material layer 203. For example, if the penetration holes are too deep, the electrolyte may more easily penetrate into the interior of the positive electrode sheet 2. At low rates, the internal reactions of the battery are relatively slow, and the excessive penetration of the electrolyte may lead to a locally high concentration of the electrolyte within the positive electrode sheet 2, accelerating the decomposition reaction of the electrolyte and causing excessive consumption of the electrolyte.

[0131] The thickness of the positive electrode active material layer 203 is also one of the factors for determining the depth of the penetration holes. The hole depth is proportional to the thickness of the active layer to avoid collapse of the positive electrode structure caused by excessive hole opening.

[0132] Furthermore, a positive electrode active material layer 203 is provided on one side of the positive electrode current collector 202, and the third penetration holes 201 are provided in the positive electrode active material layer 203. Or positive electrode active material layers 203 are provided on both sides of the positive electrode current collector 202, and the third penetration holes 201 are provided in at least one side of the positive electrode active material layer 203. It can be understood that for each side of the positive electrode active material layer 203, the depth of the third penetration holes 201 is determined based on the thickness of the positive electrode active material layer 203 where it is located.

[0133] In some embodiments provided by the present invention, the depth of the third penetration holes 201 is determined based on the weighted sum of squares of the maximum charging rate and the maximum discharging rate, as well as the thickness of the positive electrode active material layer 203 on one side of the positive electrode.

[0134] The maximum charge rate and the maximum discharge rate reflect the extreme current demands of the battery under different working scenarios. In this embodiment, by incorporating the weighted sum of squares of the two into the basis for depth determination, the lithium-ion migration requirements of the battery under different working conditions such as rapid charging and rapid discharging can be comprehensively considered, enabling the depth of the penetration pores to match the current changes in the actual operation of the battery, ensuring that lithium ions have appropriate channels and migration environments under charging or discharging conditions, and improving the overall performance and efficiency of the battery.

[0135] For example, for some electric vehicle batteries that need to be charged in a short time and have high-power output capabilities, this design method can ensure that the depth of the penetration pores of the positive electrode sheet 2 precisely matches the high-rate charge and discharge requirements of the battery, thereby optimizing the performance of the battery.

[0136] Compared with the design method that only considers a single factor (such as only considering the charge rate or the discharge rate), this design based on the weighted sum of squares can more accurately reflect the comprehensive requirements of the battery in actual use, avoiding performance imbalance caused by only focusing on one aspect.

[0137] In addition, a thicker active material layer means that lithium ions need to travel a longer distance to reach the current collector, which increases the migration resistance of lithium ions. By correlating the depth of the penetration pores with the thickness of the active material layer, the depth of the penetration pores can be adjusted according to the thickness of the active material layer of different thicknesses to ensure that the penetration of the electrolyte and the migration of lithium ions can be effectively guaranteed in the entire thickness direction of the positive electrode sheet 2.

[0138] In summary, comprehensively considering the charge and discharge rates and the thickness of the active material layer to determine the depth of the penetration pores can more precisely optimize the distribution and migration of lithium ions on the positive electrode sheet 2. By setting the third penetration pores 201 in the edge region of the positive electrode, on the one hand, the de-lithiation kinetics of the positive electrode can be improved, and the concentration polarization in the overlapping region of the positive electrode and the negative electrode can be reduced; on the other hand, the lithium intercalation kinetics of the positive electrode can be improved, the concentration polarization under high-rate discharge conditions of the battery can be reduced, and the discharge power and discharge energy retention rate of the battery can be enhanced.

[0139] In some embodiments provided by the present invention, the depth of the third penetration pores 201 satisfies the following relationship with the maximum charge rate, the maximum discharge rate, and the thickness of the positive electrode active material layer 203:

[0140]

[0141] Wherein, H1 is the depth of the third penetration pores 201, and its unit is μm. H2 is the thickness of a single layer of the positive electrode active material layer 203, and its unit is μm.

[0142] α is a proportionality coefficient, which can be a coefficient related to the intrinsic properties of the positive electrode active material, and its value ranges from 0.05 to 0.8. For example, the value of α can be 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, or 0.8.

[0143] C1 is the maximum charging rate, and C2 is the maximum discharging rate.

[0144] Both w1 and w2 are weighting coefficients.

[0145] In this embodiment, by introducing the weighting coefficients w1 and w1, the formula can achieve flexible adaptation to the charge and discharge scenarios.

[0146] For example, increasing w1, or making w1 greater than w2, for example, w1 is 0.6 and w2 is 0.25. In this way, the influence of the maximum charging rate C1 on the depth of the penetration pores can be strengthened, and the lithium-ion migration path during high-rate charging can be shortened. For example, it can be applied to occasions that require fast charging.

[0147] For example, increasing w2, or making w1 less than w2, then optimizing the weight of the maximum discharging rate C2 on the depth of the penetration pores to ensure that the electrolyte is fully infiltrated during high-rate discharging and suppress lithium deposition.

[0148] Regarding α in the formula, it is directly related to the intrinsic properties of the positive electrode material, which can make the design of the penetration pore depth more in line with the material performance and give full play to the material advantages. For example, optionally, for a positive electrode material with a high porosity (such as a silicon-based positive electrode), α can be increased accordingly to supplement its low conductivity through deep holes; for a dense material (such as graphite), α can be decreased accordingly to avoid excessive damage to the structural stability.

[0149] Of course, a quantitative relationship between α and different material properties can also be established through a large number of experiments and data analyses to achieve a more accurate design of the penetration pore depth.

[0150] It should be noted that for the positive electrode sheet, the value range of α is 0.05 to 0.8, while for the negative electrode sheet, the value range of α is 0.05 to 0.9, indicating that the negative electrode sheet allows a greater pore depth compared to the positive electrode sheet.

[0151] This is because the positive electrode active material usually has high hardness and brittleness. If the drilling depth is too large, it is easy to cause defects such as cracks and breakage in the material during the drilling process, affecting the structural integrity and performance of the electrode. While the negative electrode active material is relatively soft in texture, has good flexibility and ductility, and can allow a larger pore depth.

[0152] In addition, the electronic conductivity of the positive electrode active material is generally lower than that of the negative electrode active material. A shallower punching depth can reduce the damage to the conductive network, ensure the formation of a continuous electron transport path inside the positive electrode, and thus improve the rate performance. If the punching is too deep, it may cause a sudden drop in local conductivity and exacerbate polarization.

[0153] In some embodiments provided by the present invention, the aperture of the third penetration hole 201 is determined based on the particle size of the particles in the positive electrode active material layer 203 of the positive electrode sheet 2. For example, the third penetration hole 201 is a circular hole, and the aperture of the circular hole is determined based on the particle size of the particles in the positive electrode active material layer 203 of the positive electrode sheet 2.

[0154] The particle size of the particles in the positive electrode active material layer 203 affects the lithium ion transport path. In this embodiment, determining the aperture according to the particle size can make the size of the penetration hole adapt to the diffusion of lithium ions between the particles, reduce the resistance during lithium ion diffusion, facilitate the smooth migration of lithium ions, and improve the charge and discharge efficiency of the battery.

[0155] In addition, the adaptation of the aperture to the particle size helps to improve the wettability of the electrolyte to the positive electrode material. Good wettability can ensure that the electrolyte can fully contact each active material particle, thereby improving the overall performance of the battery.

[0156] An appropriate aperture can avoid excessive damage to the structure of the positive electrode sheet 2. If the aperture is too large, the binding force between the active material and the current collector will be weakened; if it is too small, the effect of promoting ion transport cannot be achieved. Determining the aperture based on the particle size can improve the performance while maintaining the structural stability of the electrode and extending the battery life.

[0157] In some embodiments provided by the present invention, the aperture of the third penetration hole 201 is determined based on the pure decimal power of D100 and the difference between D90 and D10 divided by D50. Or rather, the aperture of the circular hole is determined based on the pure decimal power of D100 and the difference between D90 and D10 divided by D50.

[0158] Among them, D100, D90, D50, and D10 are all particle size distribution parameter values of the particles in the positive electrode active material layer 203 of the positive electrode sheet 2. For example, D90 refers to the value at which 90% of the particles in the sample have a particle size smaller than this value.

[0159] In this embodiment, setting the pure decimal power of D100 can not only consider the limitation of the aperture by the local feature of the largest particle size particles, but also, through the pure decimal power operation, on the basis of considering the influence of large particles, reduce the excessive influence of the largest particle size particles on the aperture, that is, avoid the problem of too large aperture caused by directly using D100, thereby optimizing the limiting effect on large particles.

[0160] In addition, by dividing the difference between D90 and D10 by D50, the difference between D90 and D10 can intuitively represent the span range from the smaller particle size part to the larger particle size part in the particle size distribution. Dividing the difference between D90 and D10 by D50 is to compare this span with the average particle size of the particles to achieve normalization processing, so as to evaluate the uniformity of particle size and ensure that the obtained pore size is closer to the characteristics of the actual material.

[0161] In summary, by adjusting the pore size of the permeation pores through these parameters, the actual distribution of particle sizes and the uniformity of particle sizes in the positive electrode active material layer 203 can be more accurately reflected, ensuring that the designed pore size is more in line with the characteristics of the actual material.

[0162] In some embodiments provided by the present invention, the pore size of the third permeation pore 201 is based on:

[0163] Determined.

[0164] Among them, R1 is the diameter of the third permeation pore 201, and its unit is μm.

[0165] ε1 is a proportionality coefficient. For example, it is a coefficient related to the positive electrode design, and its value is between 0.1 and 10. For example, the value of ε1 is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 or 10.

[0166] t is a positive number less than 1. For example, t is 2 / 3, and it can also be 1 / 2 or 3 / 4.

[0167] In this embodiment, based on the above formula calculation and control, among them, (D100) t It can ensure that the pore size can adapt to the largest particles, but will not cause the pore size to be too large due to individual large particles. By adjusting t, the relationship between the pore size and the maximum particle size can be balanced. For example, reducing the value of t can inhibit the growth rate of the pore size with D100, which is suitable for scenarios with high mechanical strength requirements. Increasing the value of t can enhance the pore size adaptability of large particles, which is suitable for materials prone to blockage.

[0168] The width of the particle size distribution can be quantified. When the distribution is wide, the pore size is automatically increased to ensure that the electrolyte fully penetrates in the complex gaps.

[0169] By setting ε1, from the perspective of the positive electrode design, it can be flexibly adjusted according to the actual electrode structure, process, etc., so that the pore size design can better meet the overall electrode design requirements, providing flexibility across materials and processes. For example, for a high-porosity electrode, ε1 can be reduced, such as ε1 being 0.5, to avoid excessive damage to the structure. For a dense electrode, ε1 can be increased, such as ε1 being 5, to force open the ion channels.

[0170] Of course, a quantitative relationship between ε1 and the positive electrode can also be established through a large number of experiments and data analyses to achieve a more accurate design of the penetration hole depth.

[0171] In some embodiments provided by the present invention, between the total pore area S4 of the orifices of the third penetration holes 201 and the surface area S5 of the punched area of the positive electrode sheet 2, it satisfies: 1 / 8 * S5 ≤ S4. For example, the value of S4 is 1 / 8S5, 1 / 7S5, 1 / 6S5, 1 / 5S5, 1 / 4S5, 1 / 2S5, 2 / 3S5, 3 / 4S5, or 4 / 5S5.

[0172] In this embodiment, with such a setting, the distribution of the orifices can force the electrolyte to diffuse from the edge of the punched area to the center, solving the problem of uneven electrode wetting. The total pore area S4 ≥ 12.5% S5 can ensure that the electrolyte quickly wets the positive electrode active material layer 203.

[0173] Optionally, the third penetration holes 201 are set as polygonal holes.

[0174] In this embodiment, the edge angle design of the polygonal holes (such as triangular, hexagonal, square) can evenly disperse the stress in multiple directions, reducing local stress concentration compared with circular holes. In addition, the side-angle structure of the polygon forms a natural support framework, improving the overall compressive strength of the electrode. Moreover, the sharp edges at the sharp corners of the polygonal holes can enhance the capillary force of the electrolyte and promote rapid wetting.

[0175] It should be noted that for the negative electrode sheet, between the total pore area S1 of the orifices of the first penetration holes 103 of the main body 101 and the surface area S3 of the punched area of the negative electrode sheet 1, it satisfies: 1 / 4 * S3 ≤ S1. Between the total pore area S2 of the orifices of the second penetration holes 104 of the suspended part 102 and the surface area S3 of the punched area of the negative electrode sheet 1, it satisfies: 1 / 5 * S3 ≤ S2.

[0176] And for the positive electrode sheet, between the total pore area S4 of the orifices of the third penetration holes 201 and the surface area S5 of the punched area of the positive electrode sheet 2, it satisfies: 1 / 8 * S5 ≤ S4.

[0177] The above solution shows that the ratio of the orifice area of the penetration holes in the negative electrode sheet to the punching area is greater than that of the positive electrode sheet, because the negative electrode needs to ensure a sufficient effective through-hole rate through a larger orifice area ratio to compensate for the volume expansion during lithium intercalation, optimize the diffusion path of lithium ions in the negative electrode active material, and suppress the risk of local lithium deposition.

[0178] However, the volume expansion of the positive electrode active material is small, and the demand for pore buffer is low, so the orifice area ratio is lower. In addition, the conductivity of the positive electrode active material is poor, and too high porosity will damage the conductive network and reduce the electron transport efficiency. Therefore, it is necessary to reduce the orifice area ratio on the positive electrode active material.

[0179] Reference Figure 3 As shown, in some embodiments provided by the present invention, the third penetration holes 201 are provided on the four peripheral edges of the positive electrode sheet 2, that is, the positive electrode punching area 204 of the positive electrode sheet 2 is an annular area. For example, a frame C is made inside the edge of the positive electrode sheet 2, and the area between the edge of the positive electrode sheet 2 and the frame C is the positive electrode punching area 204. The surface area S5 of the punching area of the positive electrode is the area between the frame C and the positive electrode edge. The total orifice area S3 of the third penetration holes 201 is the sum of the orifice areas of all the third penetration holes 201.

[0180] In this embodiment, a continuous ion channel can be formed around the main body 101, significantly reducing the current density concentration phenomenon in the edge area. In addition, a dense channel can be formed at the electrode edge to preferentially guide the electrolyte to infiltrate the edge area with a high current density.

[0181] In addition, while ensuring ion transport, the annular punching area will not overly damage the structural integrity of the middle area of the main body 101. The middle area can maintain sufficient strength to support the connection between the active material and the current collector, preventing the shedding of the active material or the damage of the electrode structure caused by large-area opening, thereby maintaining the stability and reliability of the battery during long-term use.

[0182] Optionally, reference Figure 3 As shown, assuming that along the Z direction, the width of at least one side of the positive electrode punching area 204 is W1, and the size of the positive electrode sheet 2 is W, then the ratio range of W1 to W is 1:100 to 1:2. For example, the ratio of W1 to W is 1:100, 1:90, 1:80, 1:70, 1:60, 1:50, 1:40, 1:30, 1:20, 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3 or 1:2. Preferably, the ratio range of W1 to W is 1:100 to 1:20. For example, Figure 3 As shown, in the Z direction, an example where the widths of both sides of the positive electrode punching area 204 are W1 is shown.

[0183] In this embodiment, such a setting can not only shorten the lithium-ion migration path (reduce concentration polarization), but also avoid excessive sacrifice of the active material area.

[0184] For example, for a battery with high rate requirements, a larger ratio can be selected to enhance the ion transport ability. For example, the ratio of W1 to W is 1:50 to 1:20. For a battery with long life requirements, a smaller ratio can be selected to maintain a high energy density. For example, the ratio of W1 to W is 1:100 to 1:50.

[0185] Optionally, referring to Figure 3 As shown, assuming that along the X direction, the width of at least one side of the punched area of the positive electrode is H1, and the size of the positive electrode sheet 2 is H, then the ratio range of H1 to H is 1:500 to 1:2. For example, the ratio of H1 to H is 1:500, 1:450, 1:400, 1:350, 1:300, 1:250, 1:200, 1:150, 1:100, 1:90, 1:80, 1:70, 1:60, 1:50, 1:40, 1:30, 1:20, 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3 or 1:2. Preferably, the ratio range of H1 to H is 1:100 to 1:50. For example, Figure 3 As shown, in the X direction, an example is shown where the widths of both sides of the punched area of the positive electrode are H1.

[0186] In this embodiment, such a setting can not only shorten the lithium-ion migration path (reduce concentration polarization), but also avoid excessive sacrifice of the active material area.

[0187] For example, for a battery with high rate requirements, a larger ratio can be selected to enhance the ion transport ability. For example, the ratio of W1 to W is 1:70 to 1:50. For a battery with long life requirements, a smaller ratio can be selected to maintain a high energy density. For example, the ratio of W1 to W is 1:100 to 1:70.

[0188] In some embodiments provided by the present invention, the first penetration hole 103 is set as a blind hole or a through hole. Since the first penetration hole 103 is at a certain distance from the edge area of the electrode sheet, it can be set as a through hole structure, so as to flexibly adjust the kinetic performance of the overlapping area between the negative electrode and the positive electrode.

[0189] Correspondingly, the second penetration hole 104 and the third penetration hole 201 are both blind holes. Since both the second penetration hole 104 and the third penetration hole 201 are close to the edge of the electrode sheet, the strength of the active material layer is relatively lower in the middle part, and if the punching depth of the through hole is too large, it is easy to cause the active material layer after rolling to peel off from the current collector, resulting in the phenomenon of the active material layer of the electrode sheet falling off.

[0190] In an embodiment of the present invention, a pole core is further provided.

[0191] Specifically, the pole core includes the negative electrode sheet 1 and / or the positive electrode sheet 2 as described above.

[0192] It should be noted that since the pole core includes the negative electrode sheet 1 or the positive electrode sheet 2, it also includes the corresponding technical advantages, so they will not be elaborated here. Of course, the pole core further includes a separator disposed between the negative electrode sheet 1 and the positive electrode sheet 2. This application does not involve improvements to this part, so it will not be elaborated here.

[0193] In addition, for the pole core in this embodiment, the parameters of the pore structure unit can be flexibly adjusted according to the design parameters of the battery and the charge-discharge conditions, so as to improve the kinetics of the electrode and meet the development requirements of the battery.

[0194] To illustrate the technical solutions of this application, the present invention also provides Embodiment 1 - Embodiment 5, as well as Comparative Example 1 and Comparative Example 2.

[0195] Among them, Embodiment 1:

[0196] A pole core includes a positive electrode sheet 2 and a negative electrode sheet 1 with opposite polarities. The single-sided coating weight of the positive electrode sheet 2 is 153 g / m2, and the single-sided coating weight of the negative electrode sheet 1 is 71 g / m2. After the rolling process of the positive electrode sheet 2 and the negative electrode sheet 1, a porous structure unit is manufactured on the surface of the edge region of the electrode sheet by mechanical processing. The specific pore structure parameters are as follows:

[0197] For the overhang region 102 of the negative electrode sheet 1, referring to Figure 2 as shown, both L1 and D1 are 1 m.

[0198] For the main body punching region 107, the ratio of D2 to D is 1:25; the ratio of L2 to L is 1:80.

[0199] The second penetration holes 104 in the overhang region of the negative electrode sheet are circular blind holes. The diameter of the second penetration holes 104 is 20 μm, and the depth of the holes is 40 μm. The first penetration holes 103 in the main body punching region 107 are circular holes. The diameter of the first penetration holes 103 is 20 μm, and the depth of the holes is 50 μm.

[0200] Among them, the spacing between the second penetration holes 104 in the overhang region is 50 μm, and the arrangement direction of the second penetration holes 104 is parallel to the edge of the electrode sheet. The total pore area S2 of the second penetration holes 104 accounts for 20.2% of the surface area S3 of the punching region of the negative electrode sheet 1. The spacing between the first penetration holes 103 in the main body punching region 107 is 45 μm, and the total pore area S1 of the first penetration holes 103 accounts for 25.6% of the surface area S3 of the punching region of the negative electrode sheet 1.

[0201] For the positive electrode sheet 2, referring to Figure 3 as shown, in the positive electrode punching area 204, the ratio of W1 to W is 1:30, and the ratio of H1 to H is 1:100.

[0202] The third penetration hole 201 of the positive electrode sheet 2 is a circular blind hole, the diameter of the third penetration hole 201 is 15um, and the depth of the hole is 60um.

[0203] Among them, the spacing between the third penetration holes 201 in the positive electrode punching area 204 is 40um, the third penetration holes 201 are arranged in parallel with the edge of the electrode sheet, and the ratio of the total orifice area S4 of the third penetration holes 201 to the surface area S5 of the punching area of the positive electrode sheet 2 is 14.4%.

[0204] After the mechanical hole-making process for the positive electrode sheet 2 and the negative electrode sheet 1, the electrode sheets are cut into single electrode sheets through the die-cutting process. Through the Z-shaped stacking process, the positive electrode, negative electrode, and separator are stacked in sequence to assemble a stacked electrode core; through the hot pressing process, the positive electrode, negative electrode, and separator are bonded together. Through the assembly process, the stacked electrode core is sealed into the aluminum shell body, and then through processes such as liquid injection, formation, aging, and grading, a stacked square aluminum battery cell is prepared.

[0205] Example 2:

[0206] An electrode core includes a positive electrode sheet 2 and a negative electrode sheet 1 with opposite polarities. The single-sided coating weight of the positive electrode sheet 2 is 153 g / m2, and the single-sided coating weight of the negative electrode sheet 1 is 71 g / m2. After the rolling process for the positive electrode and the negative electrode sheet 1, through mechanical processing, a porous structure unit is manufactured on the surface of the edge area of the electrode sheet. The specific hole structure parameters are as follows:

[0207] For the overhang area of the negative electrode sheet 1, that is, the suspended part 102, referring to Figure 2 as shown, both L1 and D1 are 1m.

[0208] For the main body punching area 107, the ratio of D2 to D is 1:20; the ratio of L2 to L is 1:60.

[0209] The second penetration hole 104 in the overhang area of the negative electrode sheet is a circular blind hole, the diameter of the second penetration hole 104 is 20um, and the depth of the hole is 40um; the first penetration hole 103 in the main body punching area 107 is a circular hole, the diameter of the first penetration hole 103 is 20um, and the depth of the hole is 50um.

[0210] Among them, the spacing between the second permeation holes 104 in the overhang area is 40 μm, and the arrangement direction of the second permeation holes 104 is parallel to the edge of the electrode sheet. The total orifice area S2 of the second permeation holes 104 accounts for 20.2% of the surface area S3 of the perforated area of the negative electrode sheet 1. The spacing between the first permeation holes 103 in the main perforated area 107 is 35 μm, and the total orifice area S1 of the first permeation holes 103 accounts for 25.6% of the surface area S3 of the perforated area of the negative electrode sheet 1.

[0211] For the positive electrode sheet 2, refer to Figure 3 As shown, in the positive electrode perforated area 204, the ratio of W1 to W is 1:20, and the ratio of H1 to H is 1:70.

[0212] The third permeation hole 201 of the positive electrode sheet 2 is a circular blind hole, the diameter of the third permeation hole 201 is 25 μm, and the depth of the hole is 60 μm.

[0213] Among them, the spacing between the third permeation holes 201 in the positive electrode perforated area 204 is 40 μm, the third permeation holes 201 are arranged parallel to the edge of the electrode sheet, and the ratio of the total orifice area S4 of the third permeation holes 201 to the surface area S5 of the perforated area of the positive electrode sheet 2 is 30.7%.

[0214] After the mechanical hole-making process for the positive electrode and the negative electrode sheet 1, the electrode sheets are cut into single electrode sheets through the die-cutting process. Through the Z-shaped stacking process, the positive electrode, the negative electrode, and the separator are stacked in sequence to assemble a stacked electrode core; through the hot pressing process, the positive electrode, the negative electrode, and the separator are bonded together. Through the assembly process, the stacked electrode core is sealed into the aluminum shell body, and then through processes such as liquid injection, formation, aging, and grading, a stacked square aluminum battery cell is prepared.

[0215] Example 3:

[0216] An electrode core includes a positive electrode sheet 2 and a negative electrode sheet 1 with opposite polarities. The single-sided coating weight of the positive electrode sheet 2 is 153 g / m2, and the single-sided coating weight of the negative electrode sheet 1 is 71 g / m2. After the rolling process for the positive electrode sheet 2 and the negative electrode sheet 1, through mechanical processing, a porous structure unit is manufactured on the surface of the edge area of the electrode sheet. The specific pore structure parameters are as follows:

[0217] For the overhang area, i.e., the suspended part 102, of the negative electrode sheet 1, refer to Figure 2 As shown, both L1 and D1 are 1 m.

[0218] For the main perforated area 107, the ratio of D2 to D is 1:25; the ratio of L2 to L is 1:80.

[0219] The second penetration holes 104 in the overhang area of the negative electrode sheet are circular blind holes, with a diameter of 20 um and a depth of 30 um for the second penetration holes 104; the first penetration holes 103 in the main body punching area 107 are circular holes, with a diameter of 30 um and a depth of 55 um for the first penetration holes 103.

[0220] Among them, the spacing between the second penetration holes 104 in the overhang area is 35 um, and the arrangement direction of the second penetration holes 104 is parallel to the edge of the electrode sheet. The total orifice area S2 of the second penetration holes 104 accounts for 25.6% of the surface area S3 of the punching area of the negative electrode sheet 1. The spacing between the first penetration holes 103 in the main body punching area 107 is 45 um, and the total orifice area S1 of the first penetration holes 103 accounts for 34.8% of the surface area S3 of the punching area of the negative electrode sheet 1.

[0221] For the positive electrode sheet 2, refer to Figure 3 As shown, in the positive electrode punching area 204, the ratio of W1 to W is 1:20, and the ratio of H1 to H is 1:70.

[0222] The third penetration holes 201 of the positive electrode sheet 2 are circular blind holes, with a diameter of 35 um and a depth of 50 um for the third penetration holes 201.

[0223] Among them, the spacing between the third penetration holes 201 in the positive electrode punching area 204 is 45 um, the third penetration holes 201 are arranged parallel to the edge of the electrode sheet, and the ratio of the total orifice area S4 of the third penetration holes 201 to the surface area S5 of the punching area of the positive electrode sheet 2 is 47.4%.

[0224] After the mechanical hole-making process for the positive and negative electrode sheets 1, the electrode sheets are cut into single sheets through a die-cutting process. Through a Z-shaped stacking process, the positive electrode, negative electrode, and separator are stacked in sequence to assemble a stacked electrode core; through a hot pressing process, the positive electrode, negative electrode, and separator are bonded together. Through an assembly process, the stacked electrode core is sealed into an aluminum shell, and then through processes such as liquid injection, formation, aging, and grading, a stacked square aluminum battery cell is prepared.

[0225] Example 4:

[0226] An electrode core includes a positive electrode sheet 2 and a negative electrode sheet 1 with opposite polarities. The single-sided coating weight of the positive electrode sheet 2 is 174 g / m2, and the single-sided coating weight of the negative electrode sheet 1 is 80 g / m2. After the rolling process for the positive electrode sheet 2 and the negative electrode sheet 1, through a mechanical processing method, porous structure units are manufactured on the surface of the edge area of the electrode sheets. The specific hole structure parameters are as follows:

[0227] For the overhang area, i.e., the suspended part 102, of the negative electrode sheet 1, refer to Figure 2 As shown, both L1 and D1 are 1 m.

[0228] For the main body punching area 107, the ratio of D2 to D is 1:25; the ratio of L2 to L is 1:80.

[0229] The second penetration holes 104 in the overhang area of the negative electrode sheet are circular blind holes, the diameter of the second penetration holes 104 is 20 um, and the depth of the holes is 40 um; the first penetration holes 103 in the main body punching area 107 are circular holes, the diameter of the first penetration holes 103 is 20 um, and the depth of the holes is 50 um.

[0230] Among them, the spacing between the second penetration holes 104 in the overhang area is 50 um, and the arrangement direction of the second penetration holes 104 is parallel to the edge of the electrode sheet. The total orifice area S2 of the second penetration holes 104 accounts for 20.2% of the surface area S3 of the punching area of the negative electrode sheet 1. The spacing between the first penetration holes 103 in the main body punching area 107 is 45 um, and the total orifice area S1 of the first penetration holes 103 accounts for 25.6% of the surface area S3 of the punching area of the negative electrode sheet 1.

[0231] For the positive electrode sheet 2, refer to Figure 3 As shown, in the positive electrode punching area 204, the ratio of W1 to W is 1:30, and the ratio of H1 to H is 1:100.

[0232] The third penetration holes 201 of the positive electrode sheet 2 are circular blind holes, the diameter of the third penetration holes 201 is 25 um, and the depth of the holes is 60 um.

[0233] Among them, the spacing between the third penetration holes 201 in the positive electrode punching area 204 is 40 um, the third penetration holes 201 are arranged parallel to the edge of the electrode sheet, and the ratio of the total orifice area S4 of the third penetration holes 201 to the surface area S5 of the punching area of the positive electrode sheet 2 is 30.7%.

[0234] After the mechanical pore-forming process for the positive and negative electrode sheets 1, the electrode sheets are cut into single sheets through the die-cutting process, and through the Z-shaped stacking process, the positive electrode, negative electrode, and separator are stacked in sequence to assemble a stacked electrode core; through the hot-pressing process, the positive electrode, negative electrode, and separator are bonded together. Through the assembly process, the stacked electrode core is sealed into the aluminum shell body, and then through processes such as liquid injection, formation, aging, and grading, a stacked square aluminum battery cell is prepared.

[0235] Example 5:

[0236] An electrode core includes a positive electrode sheet 2 and a negative electrode sheet 1 with opposite polarities. The single-sided coating weight of the positive electrode sheet 2 is 174 g / m2, and the single-sided coating weight of the negative electrode sheet 1 is 80 g / m2. After the rolling process for the positive electrode sheet 2 and the negative electrode sheet 1, through mechanical processing, porous structure units are manufactured on the surface of the edge area of the electrode sheet. The specific pore structure parameters are as follows:

[0237] For the overhang region of the negative electrode sheet 1, i.e., the overhang portion 102, refer to Figure 2 As shown, both L1 and D1 are 1 m.

[0238] For the main body punching region 107, the ratio of D2 to D is 1:20; the ratio of L2 to L is 1:40.

[0239] The second penetration holes 104 in the overhang region of the negative electrode sheet are regular hexagonal blind holes. The side length of the second penetration holes 104 is 15 μm, and the depth of the holes is 40 μm; the first penetration holes 103 in the main body punching region 107 are regular hexagonal blind holes. The side length of the first penetration holes 103 is 20 μm, and the depth of the holes is 60 μm.

[0240] Among them, the distance between the second penetration holes 104 in the overhang region is 40 μm, and the arrangement direction of the second penetration holes 104 is parallel to the edge of the electrode sheet. The total orifice area S2 of the second penetration holes 104 accounts for 36.5% of the surface area S3 of the punching region of the negative electrode sheet 1. The distance between the first penetration holes 103 in the main body punching region 107 is 45 μm, and the total orifice area S1 of the first penetration holes 103 accounts for 51.3% of the surface area S3 of the punching region of the negative electrode sheet 1.

[0241] For the positive electrode sheet 2, refer to Figure 3 As shown, in the positive electrode punching region, the ratio of W1 to W is 1:20, and the ratio of H1 to H is 1:45.

[0242] The third penetration holes 201 of the positive electrode sheet 2 are regular hexagonal holes. The side length of the third penetration holes 201 is 20 μm, and the depth of the holes is 80 μm.

[0243] Among them, the distance between the third penetration holes 201 in the positive electrode punching region is 50 μm, the third penetration holes 201 are arranged parallel to the edge of the electrode sheet, and the ratio of the total orifice area S4 of the third penetration holes 201 to the surface area S5 of the punching region of the positive electrode sheet 2 is 41.6%.

[0244] After the mechanical hole-making process for the positive and negative electrode sheets, the electrode sheets are cut into single electrode sheets through the die-cutting process. Through the Z-shaped stacking process, the positive electrode, negative electrode, and separator are stacked in sequence to assemble a stacked electrode core; through the hot pressing process, the positive electrode, negative electrode, and separator are bonded together. Through the assembly process, the stacked electrode core is sealed into the aluminum shell body, and then through processes such as liquid injection, formation, aging, and grading, a stacked square aluminum battery cell is prepared.

[0245] Comparative Example 1:

[0246] A pole core includes a positive electrode sheet 2 and a negative electrode sheet 1 with opposite polarities. The single-sided coating weight of the positive electrode sheet 2 is 153 g / m2, and the single-sided coating weight of the negative electrode sheet 1 is 71 g / m2. After the rolling process of the positive and negative electrode sheets 1, the electrode sheets are cut into single-piece electrode sheets through a die-cutting process. Through a Z-shaped laminating process, the positive electrode, negative electrode, and separator are stacked in sequence to assemble a laminated pole core. Through a hot-pressing process, the positive electrode, negative electrode, and separator are bonded together. Through an assembly process, the laminated pole core is sealed into an aluminum shell body, and then through processes such as liquid injection, formation, aging, and grading, a laminated square aluminum battery cell is prepared.

[0247] Comparative Example 2:

[0248] A pole core includes a positive electrode sheet 2 and a negative electrode sheet 1 with opposite polarities. The single-sided coating weight of the positive electrode sheet is 174 g / m2, and the single-sided coating weight of the negative electrode sheet is 80 g / m2. After the rolling process of the positive electrode sheet and the negative electrode sheet, the electrode sheets are cut into single-piece electrode sheets through a die-cutting process. Through a Z-shaped laminating process, the positive electrode, negative electrode, and separator are stacked in sequence to assemble a laminated pole core. Through a hot-pressing process, the positive electrode, negative electrode, and separator are bonded together. Through an assembly process, the laminated pole core is sealed into an aluminum shell body, and then through processes such as liquid injection, formation, aging, and grading, a laminated square aluminum battery cell is prepared.

[0249] The batteries prepared in Examples 1, 2, 3 and Comparative Example 1 were subjected to a fast charge cycle test. The upper limit voltage (Vmax) of the cycle range was 3.65 V, and the lower limit voltage was 2.5 V. The cycle steps were as follows: At 25 °C, a 3C direct charge was used to charge to the cut-off SOC, and then left standing for 1 h; then at a 1C rate, a constant current discharge was carried out to the cut-off voltage (2.5 V), and left standing for 1 h. The above charge and discharge processes were cycled 600 times.

[0250] Furthermore, the fast charge cycle results at 25 °C are as Figure 4 shown: The cycle capacity retention rate of Comparative Example 1 was 94.3%, the capacity retention rate of Example 1 was 94.8%, the capacity retention rate of Example 2 was 94.9%, and the capacity retention rate of Example 3 was 95.4%.

[0251] The fully charged batteries after the fast charge cycle were disassembled, and the lithium deposition states in different regions of the fully charged negative electrode sheet 1 were observed as shown in Table 1 below:

[0252] Table 1 Lithium deposition degree of the negative electrode

[0253]

[0254] The definition of the lithium deposition degree at the fully charged interface of the negative electrode is as follows:

[0255] 0: No lithium deposition can be observed with the naked eye;

[0256] 1: Micro lithium deposition (the area of lithium deposition is less than 5% of the area of the active material layer in the corresponding region);

[0257] 2: Small - area lithium deposition (the area of lithium deposition is 5% - 20% of the area of the active material layer in the corresponding region);

[0258] 3: Large - area lithium deposition (the area of lithium deposition is 30% - 50% of the area of the active material layer in the corresponding region);

[0259] 4: Large - area lithium deposition (the area of lithium deposition is greater than 50% of the area of the active material layer in the corresponding region).

[0260] The batteries prepared in Examples 3 and 4 and Comparative Example 2 were fully charged to 100% SOC, and then stored and aged at 45°C for 60 days. Then, Examples 3 and 4 and Comparative Example 2 were subjected to a fast - charge cycle test. The upper - limit voltage (Vmax) of the cycle range was 3.65 V, and the lower - limit voltage was 2.5 V. The cycle steps were as follows: At 25°C, a 3C direct charge was used to charge to the cut - off SOC, and then it was left standing for 1 h; then, at a 1C rate, it was discharged at a constant current to the cut - off voltage (2.5 V) and left standing for 1 h. The above charge - discharge process was cycled 180 times. The results of the fast - charge cycle at 25°C were as Figure 5 shown: The cycle capacity retention rate of Comparative Example 2 was 95.0%, the capacity retention rate of Example 3 was 97.0%, and the capacity retention rate of Example 4 was 97.1%.

[0261] After the fast - charge - cycled batteries were fully charged and disassembled, the lithium - deposition states in different regions of the fully - charged negative electrode sheets were observed, as shown in Table 2 below:

[0262] Table 2 Degree of lithium deposition on the negative electrode

[0263]

[0264] In the embodiments of the present invention, a battery is also provided.

[0265] Specifically, the battery includes the electrode core as above.

[0266] It should be noted that since the battery includes the electrode core, it also includes all the above - mentioned advantages of the electrode core, so it will not be elaborated here.

[0267] In the embodiments of the present invention, a vehicle is also provided.

[0268] Specifically, the vehicle includes the electrode core as above or the battery as above.

[0269] It should be noted that since the vehicle includes the electrode core, it also includes all the above - mentioned advantages of the electrode core, so it will not be elaborated here.

[0270] The vehicle can be set as a vehicle or an aircraft, and the vehicle can be a pure - electric vehicle or a hybrid vehicle.

[0271] While embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A negative electrode sheet, characterized in that, For a battery, comprising: A main body portion (101) for being stacked and coincided with a positive electrode sheet (2), wherein at least a position near the edge on the surface of the main body portion (101) is provided with a first penetration hole (103); A suspended portion (102) connected to the outside of the edge of the main body portion (101) and exceeding the edge of the positive electrode sheet (2), wherein the surface of the suspended portion (102) is provided with a second penetration hole (104); Wherein, the depth of at least one of the first penetration hole (103) and the second penetration hole (104) is H1; Wherein, α is a proportionality coefficient, H2 is the thickness of a single-layer negative electrode active material layer, C1 is the maximum charge rate of the battery, C2 is the maximum discharge rate of the battery, and w1 and w2 are both weighting coefficients.

2. The negative electrode sheet according to claim 1, wherein The value range of α is 0.05 to 0.9; And / or, w1 is greater than or less than w2.

3. The negative electrode sheet according to claim 1 or 2, characterized in that, The aperture of at least one of the first penetration hole (103) and the second penetration hole (104) is R1; Wherein, ε1 is a proportionality coefficient, D100, D90, D50 and D10 are all particle size distribution parameter values in the negative electrode active material layer of the negative electrode sheet, and t is a positive number less than 1.

4. The negative electrode sheet according to claim 1 or 2, characterized in that, The total pore area S1 of the orifices of the first penetration holes (103) of the main body portion (101) and the surface area S3 of the punched area of the negative electrode sheet (1) satisfy: 1 / 4*S3 ≤ S1; And / or, the total pore area S2 of the orifices of the second penetration holes (104) of the suspended portion (102) and the surface area S3 of the punched area of the negative electrode sheet (1) satisfy: 1 / 5*S3 ≤ S2.

5. A positive electrode sheet, characterized in that, For being stacked and coincided with the main body portion (101) of the negative electrode sheet (1) of the battery, wherein at least a position near the edge on the surface of the positive electrode sheet (2) is provided with a third penetration hole (201); Wherein, the depth of the third penetration hole (201) is H1; Wherein, α is a proportionality coefficient, H2 is the thickness of a single-layer positive electrode active material layer, C1 is the maximum charge rate of the battery, C2 is the maximum discharge rate of the battery, and w1 and w2 are both weighting coefficients.

6. The positive electrode sheet according to claim 5, wherein, The value range of α is 0.05 to 0.8; And / or, w1 is greater than or less than w2.

7. The positive electrode sheet according to claim 5 or 6, characterized in that, The aperture of the third penetration hole (201) is R1; Wherein, ε1 is a proportionality coefficient, D100, D90, D50 and D10 are all particle size distribution parameter values in the positive electrode active material layer of the positive electrode sheet, and t is a positive number less than 1.

8. The positive electrode sheet according to claim 5 or 6, characterized in that, Between the total pore area S4 of the orifices of the third penetration hole (201) and the surface area S5 of the punched area of the positive electrode sheet (2), it satisfies: 1 / 8*S5 ≤ S4.

9. A pole core, characterized in that, Comprising the negative electrode sheet (1) according to any one of claims 1-4 and / or the positive electrode sheet (2) according to any one of claims 5-8.

10. A battery, characterized in that, Comprising the electrode core according to claim 9.

11. A vehicle, characterized in that, Comprising the electrode core according to claim 9 or the battery according to claim 10.

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