Battery cell pole piece, battery and vehicle

Abstract

The invention discloses a battery cell pole piece, a battery and a vehicle, and relates to the technical field of batteries. One end of the pole piece is connected with a tab, the pole piece comprises a positive current collector and positive active materials attached to the two sides of the positive current collector respectively, a first area and a second area are sequentially arranged on the positive active materials in the direction away from the tab, the first area is provided with a first blocking part, and the second area is provided with a second blocking part. According to the invention, the temperature distribution condition of the surface of the battery cell can be simulated, and grooves and holes with different densities are formed in different areas on the pole piece of the battery cell on the basis of the temperature distribution condition, so that the migration path of lithium ions in the charging process is reduced, the liquid phase transmission of the lithium ions is improved, and the dynamic performance of the battery cell is improved; and the performance of the lithium ion battery is more stable.

Description

Technical Field

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

[0002] As a new type of green energy, lithium-ion batteries have the characteristics of small size, light weight, high energy density, long cycle life, etc., and are mainly used in fields such as portable electronic products, power tools, electric vehicles, and energy storage systems. A lithium-ion battery mainly consists of two major parts, namely a battery cell and a protection board. The battery cell is equivalent to the heart of the battery, responsible for storing and releasing energy, and the protection board is equivalent to the brain of the lithium battery for management and protection.

[0003] In some related technologies, in lithium-ion batteries, the heat distribution and dissipation of batteries with different shapes are unevenly distributed. For example, the surface heat conduction ability of some battery materials is poor, so that more heat in the battery accumulates at the core position relative to the surface, and the current density and heat generation rate are also different at different positions of the battery; the above inconsistencies are further amplified in some large-size batteries, so that it is impossible to balance uniform high energy and high power performance in the battery cell, and there are also situations where the dynamic performance of the battery cells in different regions is different. Summary of the Invention

[0004] In order to solve at least one of the problems mentioned in the above background art, the present application provides an electrode sheet of a battery cell, a battery, and a vehicle. By simulating and analyzing the temperature distribution on the surface of the battery cell, different-density grooves and openings are set in different regions on the electrode sheet of the battery cell based on this, so as to reduce the migration path of lithium ions during charging, improve the liquid-phase transmission of lithium ions, improve the dynamic performance of the battery cell, and make the performance of the lithium-ion battery more stable.

[0005] The specific technical solutions provided by the embodiments of the present application are as follows:

[0006] In the first aspect, an electrode sheet of a battery cell is provided. One end of the electrode sheet is connected to an electrode tab. The electrode sheet includes a positive current collector and positive active materials respectively attached to both sides of the positive current collector. A first region and a second region are sequentially arranged on the positive active material along the direction away from the electrode tab. A first barrier portion is arranged in the first region, and a second barrier portion is arranged in the second region.

[0007] In a specific embodiment, the first region includes an upper region and a middle region, which are sequentially arranged along the direction away from the electrode tab, and the density parameter and depth parameter of the first barrier portion in the upper region and the middle region are different.

[0008] In a specific embodiment, the first barrier portion is provided as micropores, and the pore density of the micropores in the upper end region is 2,000 to 5,000 pores / mm 2 , and the pore depth is 30 to 50 μm.

[0009] In a specific embodiment, the pore density of the micropores in the upper end region is set to 2,000 pores / mm 2 , 2,100 pores / mm 2 , 2,200 pores / mm 2 , 2,300 pores / mm 2 , 2,400 pores / mm 2 , 2,500 pores / mm 2 , 2,600 pores / mm 2 , 2,700 pores / mm 2 , 2,800 pores / mm 2 , 2,900 pores / mm 2 , 3,000 pores / mm 2 , 3,100 pores / mm 2 , 3,200 pores / mm 2 , 3,300 pores / mm 2 , 3,400 pores / mm 2 , 3,500 pores / mm 2 , 3,600 pores / mm 2 , 3,700 pores / mm 2 , 3,800 pores / mm 2 , 3,900 pores / mm 2 , 4,000 pores / mm 2 , 4,100 pores / mm 2 , 4,200 pores / mm 2 , 4,300 pores / mm 2 , 4,400 pores / mm 2 , 4,500 pores / mm 2 , 4,600 pores / mm 2 , 4,700 pores / mm 2 , 4,900 pores / mm 2 , 4,900 pores / mm 2 or 5,000 pores / mm 2 among others.

[0010] In a specific embodiment, the pore depth of the micropores in the upper end region is set to one of 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm, 41 μm, 42 μm, 43 μm, 44 μm, 45 μm, 46 μm, 47 μm, 48 μm, 49 μm, or 50 μm.

[0011] In a specific embodiment, the pore density of the micropores in the middle region is 300 to 2000 pores / mm 2 , and the pore depth is 1 to 30 μm.

[0012] In a specific embodiment, the pore density of the micropores in the middle region is set to 300 pores / mm 2 , 310 pores / mm 2 , 320 pores / mm 2 , 330 pores / mm 2 , 340 pores / mm 2 , 360 pores / mm 2 , 360 pores / mm 2 , 370 pores / mm 2 , 380 pores / mm 2 , 390 pores / mm 2 , 400 pores / mm 2 , 450 pores / mm 2 , 500 pores / mm 2 , 550 pores / mm 2 , 600 pores / mm 2 , 650 pores / mm 2 , 700 pores / mm 2 , 750 pores / mm 2 , 800 pores / mm 2 , 850 pores / mm 2 , 900 pores / mm 2 , 950 pores / mm 2 , 1000 pores / mm 2 , 1050 pores / mm 2 , 1100 pores / mm 2 , 1150 pores / mm 2 , 1200 pores / mm 2 , 1250 pores / mm 2 , 1300 pores / mm 2 , 1350 pores / mm 2 , 1400 pores / mm 2 , 1450 pores / mm 2 , 1500 pores / mm 2 , 1550 pores / mm 2 , 1600 pores / mm 2 , 1650 pores / mm 2 , 1700 pores / mm 2 , 1750 pores / mm 2 , 1800 pores / mm 2 , 1850 pores / mm 2 , 1900 pores / mm2 、1950 pieces / mm 2 or 2000 pieces / mm 2 either one of these.

[0013] In a specific embodiment, the pore depth of the micropores in the middle region is set to be one of 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm or 30μm.

[0014] In a specific embodiment, the micropores are formed by laser drilling, and the depth direction of the micropores is perpendicular to the plane where the positive current collector is located.

[0015] In a specific embodiment, the diameter of the micropores is 1 - 100μm.

[0016] In a specific embodiment, the diameter of the micropores is set to be one of 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm or 100μm.

[0017] In a specific embodiment, the calculation formula (1) for the setting ratio of the micropores on the positive electrode active material is as follows:[[]]

[0018]

[0019] where i is 1 or 2. When i = 1, it represents the upper region in the first region; when i = 2, it represents the middle region in the first region; R i represents the micropore ratio of the i - region of the positive electrode active material; M Li represents the mass loss of the electrode sheet after setting the micropores in the i - region compared to before setting the micropores; C w represents the single - side coating mass of the positive electrode active material; A i represents the proportion of the i - region of the positive electrode active material in the surface area of the electrode sheet;

[0020] where the mass loss of the electrode sheet before and after setting the micropores in the i - region is calculated by the calculation formula (2):

[0021] M L = σ a％ *S*a% (2)

[0022] Among them, M Li represents the mass loss of the electrode sheet after setting the micropores in the i region relative to the electrode sheet without micropores; S represents the bottom area of the electrode sheet; σ a％ represents the electrode sheet surface loading limited by a% mass loss; the value range of a% is 0.1% to 5%.

[0023] In a specific embodiment, the second barrier portion is set as a groove, and the length direction of the groove is parallel to the length direction or the width direction of the positive electrode active material.

[0024] In a specific embodiment, the interval between the two grooves ranges from 10 to 2000 μm, the depth of the groove is 1 to 20 μm, and the width of the groove is 1 to 2000 μm.

[0025] In a specific embodiment, the interval between the two grooves is set to one of 10 μm, 20 μm, 30 μm, 50 μm, 100 μm, 120 μm, 150 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 1100 μm, 1200 μm, 1300 μm, 1400 μm, 1500 μm, 1600 μm, 1700 μm, 1800 μm, 1900 μm or 2000 μm.

[0026] In a specific embodiment, the depth of the groove is set to one of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm.

[0027] In a specific embodiment, the width of the groove is set to one of 1 μm, 10 μm, 20 μm, 30 μm, 50 μm, 100 μm, 120 μm, 150 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 1100 μm, 1200 μm, 1300 μm, 1400 μm, 1500 μm, 1600 μm, 1700 μm, 1800 μm, 1900 μm or 2000 μm.

[0028] In a second aspect, a battery is provided, the battery includes a positive electrode sheet, a negative electrode sheet and a tab, and the positive electrode sheet is set as the cell electrode sheet as described above.

[0029] In a third aspect, a vehicle is provided, which includes the electrode sheet or battery as described above.

[0030] The embodiments of the present application have the following beneficial effects:

[0031] 1. The solution provided by the embodiments of the present application simulates the discharge process of the battery to obtain a temperature change trend diagram of different regions on the battery electrode sheet. By setting laser drilling and roll slitting in different temperature regions, a first barrier portion is distributed in the first region of the active material layer in the positive electrode sheet, and a second barrier portion is formed in the second region. By setting the first barrier portions with different depths and densities, more lithium ion migration path points can be formed, thereby improving the charge-discharge rate performance of the lithium ion battery and making the performance of the lithium ion battery more stable.

[0032] 2. Through the setting of multiple micropores and grooves on the electrode sheet, the expansion of the electrode sheet during battery use can be alleviated, reserving space for this expansion to reduce the possibility of deformation of the battery electrode sheet.

[0033] 3. When setting the micropore density in the first region and the second region and the interval range between the grooves, it is also configured in combination with the simulation results of the current density in different regions of the battery electrode sheet, so as to improve the problem of uneven local current distribution through the setting of the grooves and micropores. Description of the Drawings

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0035] Figure 1 Showing the surface temperature distribution diagram of the electrode sheet during the discharge process of the battery according to the present application;

[0036] Figure 2 Showing the schematic diagram of the positive electrode active material on the electrode sheet according to the present application;

[0037] Figure 3 Showing the schematic diagrams of different groove shapes according to the present application;

[0038] Figure 4 Showing the schematic diagram of the slitting method according to the present application;

[0039] In the figure, 1 is the positive electrode active material; 2 is the tab; 3 is the first region; 301 is the upper region; 302 is the middle region; 4 is the second region; 5 is the first barrier portion; 6 is the second barrier portion; 7 is the first roller; 8 is the second roller; 9 is the grooved blade. Detailed implementation manner

[0040] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are only a part rather than all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without making creative efforts shall fall within the protection scope of the present application.

[0041] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation manner.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the specification of this application herein are only for the purpose of describing specific implementation manners and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0043] In the embodiments of the present application, "upper" and "lower" are both based on Figure 2 and Figure 3 the orientation shown in

[0044] In one embodiment, as shown in Figure 2 and Figure 3As shown in the figure, in the electrode sheet of this embodiment, the electrode sheet includes a positive current collector and positive active materials 1 respectively attached to both sides of the positive current collector. At the end of the electrode sheet, there are also two tabs 2, namely a positive tab and a negative tab. By simulating the discharge state during the use of the battery where the electrode sheet is located, the surface temperature distribution map of the electrode sheet during the discharge process of the battery is obtained. By combining the surface temperature distribution map of the electrode sheet, the regions with different temperatures are divided to form a first region 3 and a second region 4 arranged in sequence along the direction away from the tab 2 on the positive active material 1. And it is set that the temperature of the battery where the first region 3 is located during discharge is higher than the temperature of the battery where the second region 4 is located during discharge. A first barrier 5 is provided in the first region 3, and a second barrier 6 is provided in the second region 4. By providing the first barrier 5 and the second barrier 6, the migration path of lithium ions during the charging process is reduced, thereby improving the liquid-phase transport of lithium ions in the battery.

[0045] Furthermore, according to the temperature distribution range in the first region 3, the first region 3 is divided into an upper region 301 and a middle region 302, where the upper region 301 and the middle region 302 are arranged in sequence along the direction away from the tab 2. Since the temperature ranges of the upper region 301 and the middle region 302 are different, the density parameter and depth parameter of the first barrier 5 in the upper region 301 and the middle region 302 are set differently. As Figure 1 shown, it can be seen from the temperature distribution map of the battery where the electrode sheet is located selected in this embodiment that the temperature in the upper region 301 is higher than that in the middle region 302, that is, the density of the first barrier 5 in the upper region 301 is greater than the density of the first barrier 5 in the middle region 302, and at the same time, the depth of the first barrier 5 in the upper region 301 is greater than the depth of the first barrier 5 in the middle region 302.

[0046] In a specific embodiment, when dividing the first region 3 and the second region 4 in the electrode sheet, the current distribution of the battery where the electrode sheet is located is also simulated to obtain the current distribution map of the battery where the electrode sheet is located. Through comprehensive analysis and division by combining the current density distribution and temperature change distribution of each region in the current distribution map. At the same time, the distribution density of the second barrier 6 in the electrode sheet can be set in combination with the current density distribution in the current distribution map. By setting the second barrier 6 and the first barrier 5 with different distribution densities, the problem of uneven current distribution in the battery electrode sheet is alleviated.

[0047] Specifically, the first barrier 5 in this embodiment is set as micropores, and several micropores are evenly distributed in the first region 3. The depth direction of the micropores is perpendicular to the plane where the positive active material 1 is located. The pore density of the micropores in the upper region 301 is set to be 2000 - 5000 pieces / mm 2 , and the pore depth is 30 - 50 μm.

[0048] Among them, the pore density of the micropores in the upper region includes, but is not limited to, 2000 pores / mm 2 , 2100 pores / mm 2 , 2200 pores / mm 2 , 2300 pores / mm 2 , 2400 pores / mm 2 , 2500 pores / mm 2 , 2600 pores / mm 2 , 2700 pores / mm 2 , 2800 pores / mm 2 , 2900 pores / mm 2 , 3000 pores / mm 2 , 3100 pores / mm 2 , 3200 pores / mm 2 , 3300 pores / mm 2 , 3400 pores / mm 2 , 3500 pores / mm 2 , 3600 pores / mm 2 , 3700 pores / mm 2 , 3800 pores / mm 2 , 3900 pores / mm 2 , 4000 pores / mm 2 , 4100 pores / mm 2 , 4200 pores / mm 2 , 4300 pores / mm 2 , 4400 pores / mm 2 , 4500 pores / mm 2 , 4600 pores / mm 2 , 4700 pores / mm 2 , 4900 pores / mm 2 , 4900 pores / mm 2 or 5000 pores / mm 2 。

[0049] In a specific embodiment, the pore depth of the micropores in the upper region includes, but is not limited to, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, or 50μm.

[0050] In a specific embodiment, the pore density of the micropores in the middle region is 300 - 2000 pores / mm 2 . Specifically, the pore density of the micropores in the middle region includes, but is not limited to, 300 pores / mm 2, 310 per mm 2 , 320 per mm 2 , 330 per mm 2 , 340 per mm 2 , 360 per mm 2 , 360 per mm 2 , 370 per mm 2 , 380 per mm 2 , 390 per mm 2 , 400 per mm 2 , 450 per mm 2 , 500 per mm 2 , 550 per mm 2 , 600 per mm 2 , 650 per mm 2 , 700 per mm 2 , 750 per mm 2 , 800 per mm 2 , 850 per mm 2 , 900 per mm 2 , 950 per mm 2 , 1000 per mm 2 , 1050 per mm 2 , 1100 per mm 2 , 1150 per mm 2 , 1200 per mm 2 , 1250 per mm 2 , 1300 per mm 2 , 1350 per mm 2 , 1400 per mm 2 , 1450 per mm 2 , 1500 per mm 2 , 1550 per mm 2 , 1600 per mm 2 , 1650 per mm 2 , 1700 per mm 2 , 1750 per mm 2 , 1800 per mm 2 , 1850 per mm 2 , 1900 per mm 2 , 1950 per mm 2 or 2000 per mm 2 .

[0051] Specifically, the pore depth of the micro-pores in the middle region 302 is set to be 1 to 30 μm. Among them, the pore depth of the micro-pores includes, but is not limited to, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm or 30 μm.

[0052] Further, the diameter of the micro-pores 5 is set to be 1 to 100 μm. Among them, the diameter of the micro-pores 5 includes, but is not limited to, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 30 μm, 35 μm, 40 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm or 100 μm.

[0053] It should be noted that the micro-pores on the electrode sheet are obtained by laser drilling. The pores of the micro-pores formed by the laser etching method are small, while the porosity of the grooves formed by the grooving method is relatively large. Through the cooperation of the grooves and the micro-pores, not only the adhesiveness of the active material on the electrode sheet is maintained within the normal range, but also the problem of electrode sheet wettability is alleviated, further ensuring the overall performance of the battery.

[0054] In a specific embodiment, the temperature distribution in the battery is different for different types of batteries. Specifically, when the battery is a cylindrical battery, the temperature at the inner center of the cylindrical battery is higher than the surface temperature, so several micro-pores are formed by laser etching at the center position. When the battery is a soft-pack battery or a square battery, the temperature at the position where the tab 2 is located is higher than other positions, so several micro-pores are formed by laser etching in the area where the tab 2 is located.

[0055] Further, through the analysis of the temperature distribution map on the surface of the electrode sheet during the discharge process of the battery where the electrode sheet is located, it can be clearly obtained that since the resistance of the positive aluminum current collector is greater than that of the negative copper current collector, the temperature in the area of the positive tab 2 is higher than that in the area of the negative tab 2. Therefore, when laser drilling is performed on the positive electrode sheet compared to the negative electrode sheet, the distribution density of the micro-pores is greater and the etching depth is stronger.

[0056] In a specific embodiment, the setting ratio of the micro-pores on the positive active material is obtained through the calculation formula (1), specifically as follows:

[0057]

[0058] Among them, i is 1 or 2. When i is 1, it represents the upper region in the first region; when i is 2, it represents the middle region in the first region; R iThe micropore ratio of region i representing the positive electrode active material; M Li The mass loss of the electrode sheet after the micropores are set in region i relative to the electrode sheet without micropores; C w The single-sided coating mass of the positive electrode active material; A i The proportion of region i in the positive electrode active material in the surface area of the electrode sheet;

[0059] Wherein, the mass loss of the electrode sheet after the micropores are set in region i relative to the electrode sheet without micropores is calculated by the calculation formula (2):

[0060] M Li = σ a％ * S * a% (2)

[0061] Wherein, M Li represents the mass loss of the electrode sheet after the micropores are set in region i relative to the electrode sheet without micropores; S represents the bottom area of the electrode sheet; σ a％ represents the electrode sheet surface loading limited by a mass loss of a%; the value range of a% is 0.1% to 5%.

[0062] Combined with the above calculation formula, the micropore setting ratio on different electrode sheet areas is configured to reduce the migration path of lithium ions during charging, improve the liquid-phase transport of lithium ions, and improve the cell dynamics performance, making the performance of the lithium-ion battery more stable.

[0063] Further, as Figure 2 shown, a second barrier portion 6 is provided in the second region 4 on the positive electrode active material 1. The second barrier portion 6 is set as a groove, and the length direction of the groove is parallel to the length direction of the positive electrode active material 1 or the width direction of the positive electrode active material 1 along the length direction parallel to the groove, that is, in this embodiment, the length direction of the groove is parallel to the width direction of the positive electrode active material 1.

[0064] In this embodiment, the temperature distribution change in the battery is also adapted by setting the distance between the two grooves, as well as the depth and width of the groove. Specifically, the interval range between the two grooves is 10 to 2000 μm, including but not limited to 10 μm, 20 μm, 30 μm, 50 μm, 100 μm, 120 μm, 150 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 1100 μm, 1200 μm, 1300 μm, 1400 μm, 1500 μm, 1600 μm, 1700 μm, 1800 μm, 1900 μm or 2000 μm.

[0065] Further, the depth of the groove 6 is set to 1 to 20 μm, including but not limited to 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm; the width of the groove 6 is set to 1 to 2000 μm, including but not limited to 1 μm, 10 μm, 20 μm m, 30μm, 50μm, 100μm, 120μm, 150μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm, 1000μm, 1100μm, 1200μm, 1300μm, 1400μm, 1500μm, 1600μm, 1700μm, 1800μm, 1900μm or 2000μm.

[0066] Furthermore, the shape of the rolled groove in this embodiment is not limited, including but not limited to a triangle, a cube, a cuboid, a trapezoid, a pyramid, a spherical cap, a cylinder, a cone, a straight groove, a diagonal groove, an arc groove or a folded groove.

[0067] The grooves in the electrode sheet are cut by cutting on a roller, and then a rolling device formed by the cooperation of the blades on two rollers is used to cut grooves on the electrode sheet to form grooves, and the depth direction of the grooves is perpendicular to the plane where the positive electrode current collector is located. Figure 4 As shown, the two rollers include a first roller 7 with a raised surface and a second roller 8 with a grooved surface. The electrode sheet to be grooved is placed between the first roller 7 and the second roller 8. The groove blade 9 on the first roller 7 or the second roller 8 is a surface structure, and the needle is a point structure. The strength of the groove is higher than that of the steel needle, thereby reducing the possibility of deformation or breakage of the groove blade 9 on the roller. The first roller 7 and the second roller 8 cooperate in groove opening to achieve groove opening on the positive electrode active material 1 on the electrode sheet.

[0068] It should be noted that when the length direction of the groove blades 9 on the first roller 7 and the second roller 8 in this embodiment is parallel to the rotation direction of the roller, a vertical groove is formed on the surface of the pole piece; when the length direction of the groove blades 9 on the first roller 7 and the second roller 8 in this embodiment is perpendicular to the rotation direction of the roller, a longitudinal groove is formed on the surface of the pole piece.

[0069] Among them, in order to implement the present solution to be able to prepare grooves of different shapes, it is set that the groove blade 9 in this embodiment can be configured in different shapes, and the blade shapes include but are not limited to vertical strip shape, horizontal strip shape, inclined strip shape, arc pattern, the blade can be continuous straight line (or curve), the blade can be dotted line shape, triangular blade, trapezoidal blade or square blade, the size of the blade can also be set, the width and depth of the blade can also be configured and adjusted, and the gap of the blade can be configured and adjusted.

[0070] In this embodiment, the setting area of the groove also includes that for the wound structure battery cell, the roller pressing groove area is located at the corner position during winding; for the stacked structure battery cell, the roller pressing groove area is located at a position 1-3 mm from the edge of the electrode tab.

[0071] It should be noted that the positive electrode tab in this embodiment includes but is not limited to ternary, lithium iron phosphate, lithium manganese iron phosphate, sodium battery, lithium cobalt oxide or a positive electrode tab mixed with several materials.

[0072] Through the solution provided by this embodiment, by simulating the discharge process of the battery, a temperature change trend diagram of different regions on the battery electrode tab is obtained. By setting laser drilling and roller pressing grooving in different temperature regions, a number of micropores are distributed in the first region 3 of the active material layer in the positive electrode tab, and a number of grooves are formed in the second region 4. By setting micropores with different depths and densities, more lithium ion migration path points can be formed, thereby improving the charge-discharge rate performance of the lithium ion battery and making the performance of the lithium ion battery more stable.

[0073] The setting of multiple micropores and grooves on the electrode tab can relieve the expansion of the electrode tab during the use of the battery, reserve space for this expansion, and reduce the possibility of deformation of the battery electrode tab. When setting the micropore density and the interval range between the grooves in the first region 3 and the second region 4, it is also configured in combination with the simulation results of the current density in different regions of the battery electrode tab, so as to improve the problem of uneven local current distribution through the setting of the first barrier part and the second barrier part.

[0074] Corresponding to the above embodiment, this embodiment proposes a battery cell electrode tab. The difference between this embodiment and the above embodiment is that, in combination with the surface temperature distribution diagram of the electrode tab of the battery during discharge, the electrode tab is divided into seven more specific regions, including the tab end region, the upper region, the upper-middle region, the middle region, the lower-middle region, the lower region and the bottom region. And different parameters such as micropore density, micropore depth, groove density and groove depth are respectively set in the above regions. By further detailed division of the upper region of the electrode tab, the improvement of the problem of uneven current distribution is strengthened, the charge-discharge rate performance of the lithium ion battery is improved, and the performance of the lithium ion battery is made more stable.

[0075] Corresponding to the above embodiments, the present application provides a battery, which includes a positive electrode tab, a negative electrode tab, and an electrode ear 2. The positive electrode tab is set as the cell electrode tab as described above.

[0076] In a specific embodiment, one end of the electrode tab is connected to the electrode ear. The electrode tab includes a positive current collector and positive active materials 1 respectively attached to both sides of the positive current collector. A first region 3 and a second region 4 are sequentially arranged on the positive active materials 1 along the direction away from the electrode ear 2. A first barrier portion 5 is arranged in the first region 3, and a second barrier portion 6 is arranged in the second region 4.

[0077] In a specific embodiment, the first region 3 includes an upper end region 301 and a middle region 302, which are sequentially arranged along the direction away from the electrode ear 2. The density parameter and depth parameter of the first barrier portion 5 in the upper end region 301 and the middle region 302 are different.

[0078] In a specific embodiment, the pore density of the micropores in the upper end region 301 is 2,000 - 5,000 pores / mm 2 , and the pore depth is 30 - 50 μm.

[0079] In a specific embodiment, the pore density of the micropores in the middle region 302 is 300 - 2,000 pores / mm 2 , and the pore depth is 1 - 30 μm.

[0080] In a specific embodiment, the micropores are formed by laser drilling, and the depth direction of the micropores is perpendicular to the plane where the positive current collector is located.

[0081] In a specific embodiment, the diameter of the micropores is 1 - 100 μm.

[0082] In a specific embodiment, the calculation formula (1) for the setting ratio of the micropores on the positive active materials 1 is:

[0083]

[0084] where i is 1 or 2. When i is 1, it represents the upper end region in the first region; when i is 2, it represents the middle region in the first region; R i represents the micropore ratio of the i region of the positive active materials; M Li represents the mass loss of the electrode tab after the micropores are set in the i region compared with the electrode tab without the micropores; C w represents the single-sided coating mass of the positive active materials; A i represents the proportion of the i region of the positive active materials in the surface area of the electrode tab;

[0085] where the mass loss of the electrode tab after the micropores are set in the i region compared with the electrode tab without the micropores is calculated by the calculation formula (2):

[0086] M Li = σ a％ *S*a% (2)

[0087] Among them, M Li represents the mass loss of the electrode sheet after setting micropores in the i region relative to the electrode sheet without micropores; S represents the bottom area of the electrode sheet; σ a％ represents the areal loading of the electrode sheet limited by a mass loss of a%; the value range of a% is 0.1% to 5%.

[0088] In a specific embodiment, the second barrier portion 6 is provided as a groove, and the length direction of the groove is parallel to the length direction or the width direction of the positive electrode active material 1.

[0089] In a specific embodiment, the interval between two grooves ranges from 10 to 2000 μm, the depth of the groove 6 is 1 to 20 μm, and the width of the groove is 1 to 2000 μm.

[0090] Corresponding to the above embodiment, this embodiment provides a vehicle, which includes the above battery or the above cell electrode sheet. The battery includes a positive electrode sheet, a negative electrode sheet, and an electrode tab 2, and the positive electrode sheet is provided as the above cell electrode sheet.

[0091] The above are only the preferred embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell electrode, one end of the electrode is connected to a tab (2), characterized in that, The electrode includes a positive current collector and positive active materials (1) respectively attached to both sides of the positive current collector. A first region (3) and a second region (4) are sequentially arranged on the positive active materials (1) along the direction away from the tab (2). A first barrier portion (5) is arranged in the first region (3), and a second barrier portion (6) is arranged in the second region.

2. The electrode sheet of the battery cell according to claim 1, characterized in that, The first region (3) includes an upper end region (301) and an intermediate region (302). The upper end region (301) and the intermediate region (302) are sequentially arranged along the direction away from the tab (2). The density parameter and depth parameter of the first barrier portion (5) in the upper end region (301) and the intermediate region (302) are different.

3. The electrode sheet of the battery cell according to claim 2, characterized in that, The first barrier portion (5) is provided with micropores, and the pore density of the micropores in the upper end region (301) is 2,000 to 5,000 pores / mm 2 , and the pore depth is 30 to 50 μm.

4. The electrode sheet of the battery cell according to claim 3, characterized in that The pore density of the micropores in the middle region (302) is 300 to 2000 pores / mm 2 , and the pore depth is 1 to 30 μm.

5. The electrode sheet of the battery cell according to claim 3 or 4, wherein The diameter of the micropores is 1 - 100 μm.

6. The electrode sheet of the battery cell according to claim 3 or 4, characterized in that, The calculation formula (1) for the setting ratio of the micropores on the positive active materials (1) is: where i is 1 or 2. When i is 1, it represents the upper region in the first region; when i is 2, it represents the middle region in the first region; R i represents the micropore ratio of the i-region of the positive electrode active material; M Li represents the mass loss of the electrode sheet after the micropores are provided in the i-region compared to the electrode sheet without the micropores; C w represents the single-sided coating mass of the positive electrode active material; A i represents the proportion of the i-region in the positive electrode active material in the surface area of the electrode sheet; Among them, the mass loss of the electrode after the micropores are arranged in the i region relative to the electrode without the micropores is calculated by the calculation formula (2): M Li = σ a％ * S * a% (2) Among them, M Li represents the mass loss of the electrode after setting the micropores in the i region relative to the electrode without the micropores; S represents the bottom area of the electrode; σ a％ represents the areal loading of the electrode limited by a mass loss of a%; the value range of a% is 0.1% to 5%.

7. The electrode sheet of the battery cell according to any one of claims 1 to 4, characterized in that The second barrier portion (6) is arranged as a groove, and the length direction of the groove is parallel to the length direction or the width direction of the positive active materials (1).

8. The electrode sheet of the battery cell according to claim 7, characterized in that, The interval range between the two grooves is 10 - 2000 μm, the depth of the groove is 1 - 20 μm, and the width of the groove is 1 - 2000 μm.

9. A battery, characterized in that, The battery includes a positive electrode, a negative electrode, and a tab (2), and the positive electrode is set as the battery electrode according to any one of claims 1 - 8.

10. A vehicle, characterized in that, The vehicle includes the battery electrode according to any one of claims 1 - 8 or the battery according to claim 9.

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