A method for die cutting a pole piece, a pole piece, and a battery

Abstract

The application provides a method for die cutting a pole piece, the pole piece and a battery. The method for die cutting the pole piece comprises the following steps: providing a pole piece to be die cut and a laser die cutting device, the surface of the pole piece to be die cut has a coated area and a non-coated area located on at least one side of the coated area, the pole piece to be die cut comprises an active material located in the coated area; obtaining a density feature of the active material, and determining a die cutting parameter of the pole piece to be die cut based on a correlation between the density feature of the active material and the die cutting parameter of the pole piece to be die cut; and die cutting the pole piece to be die cut in the non-coated area according to the die cutting parameter of the pole piece to be die cut. The method solves the problems of strip feeding and strip breaking in the die cutting process of the pole piece in the prior art, and improves the production efficiency and the yield of the pole piece by optimizing the relationship between the die cutting parameter and the density feature of the active material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a method for die cutting of an electrode sheet, an electrode sheet and a battery. BACKGROUND

[0002] Lithium ion batteries are widely used in electronic consumer products, energy storage devices and power systems due to their high output voltage, high energy density, high power density, long cycle life and good environmental protection characteristics.

[0003] In the production process of high energy density batteries, a laser cutting machine concentrates a laser beam to a focal point area to form a cutting focal point. In the focal point area, the laser power is the largest and the cutting effect is the best. However, when the range exceeds the cutting focal point, the laser power will decay with the increase of the distance, resulting in incomplete cutting of the foil part away from the cutting focal point, thereby causing the high specific energy battery to easily have die cutting strip or strip breaking problems during the machining process, affecting the production efficiency and product quality. SUMMARY

[0004] Embodiments of the present application provide a method for die cutting of an electrode sheet, an electrode sheet and a battery to solve or at least partially solve the deficiencies in the background art.

[0005] In a first aspect, embodiments of the present application provide a method for die cutting of an electrode sheet, comprising:

[0006] providing an electrode sheet to be die cut, the electrode sheet to be die cut having a coated area on the surface and a non-coated area on at least one side of the coated area, the electrode sheet to be die cut including an active material in the coated area;

[0007] obtaining a density characteristic of the active material, and determining a die cutting parameter of the electrode sheet to be die cut based on an association relationship 17≤(1000D+VF) / M≤20 between the density characteristic of the active material and the die cutting parameter of the electrode sheet to be die cut, wherein D is the tap density of the active material, V is the moving speed of the electrode sheet to be die cut during die cutting, F is the electrode sheet tension of the electrode sheet to be die cut during die cutting, and M is the single-sided area density of the active material;

[0008] According to the die cutting parameter of the electrode sheet to be die cut, the electrode sheet to be die cut in the non-coated area is die cut.

[0009] In an embodiment, the density characteristic of the active material includes the tap density of the active material and the single-sided area density of the active material.

[0010] The die cutting parameter of the electrode sheet to be die cut includes the moving speed of the electrode sheet to be die cut during die cutting and the electrode sheet tension of the electrode sheet to be die cut during die cutting.

[0011] In an embodiment, the tab sheet to be die-cut has a tab sheet tension during the die-cutting process greater than or equal to 100 N and less than or equal to 200 N.

[0012] In an embodiment, the active material has a single-sided area density greater than or equal to 200 g / m 2 and less than or equal to 225 g / m 2 .

[0013] In an embodiment, the active material has a compacted density greater than or equal to 2.58 g / cm 3 and less than or equal to 2.62 g / cm 3 .

[0014] In an embodiment, the tab sheet to be die-cut has a moving speed during the die-cutting process greater than or equal to 30 m / min and less than or equal to 60 m / min.

[0015] In an embodiment, the tab sheet to be die-cut has a thickness greater than or equal to 165 microns and less than or equal to 198 microns.

[0016] In an embodiment, the step of die-cutting the tab sheet to be die-cut in the non-coated area according to the die-cutting parameters of the tab sheet to be die-cut comprises:

[0017] die-cutting the tab sheet to be die-cut in the non-coated area using a laser die-cutting mechanism to form a tab;

[0018] transferring the die-cut tab sheet to a slitting mechanism, and slitting the tab sheet to be die-cut by the slitting mechanism;

[0019] transferring the slitted tab sheet to a winding mechanism, and winding the tab sheet by the winding mechanism.

[0020] In a second aspect, an embodiment of the present application provides a tab sheet, which is obtained by the die-cutting method of the tab sheet according to the first aspect.

[0021] In a third aspect, an embodiment of the present application provides a battery, which comprises the tab sheet according to the second aspect.

[0022] The embodiment of the present application has the beneficial effects that the embodiment of the present application provides a method for die cutting a pole piece, a pole piece and a battery. The method for die cutting the pole piece comprises the following steps: providing a pole piece to be die cut and a laser die cutting device, the surface of the pole piece to be die cut has a coated area and a non-coated area located on at least one side of the coated area, the pole piece to be die cut comprises an active material located in the coated area; obtaining a density feature of the active material, and determining a die cutting parameter of the pole piece to be die cut based on the correlation between the density feature of the active material and the die cutting parameter of the pole piece to be die cut; and die cutting the pole piece to be die cut in the non-coated area according to the die cutting parameter of the pole piece to be die cut. The method solves the problems of strip feeding and strip breaking in the die cutting process of the pole piece in the prior art, and improves the production efficiency and the yield of the pole piece by optimizing the relationship between the die cutting parameter and the density feature of the active material. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0024] Figure 1 A structure schematic diagram of the pole piece to be die cut provided by the embodiment of the present application;

[0025] Figure 2 A structure schematic diagram of the pole piece die cutting device provided by the embodiment of the present application;

[0026] Figure 3 A flowchart of the pole piece die cutting method provided by the embodiment of the present application;

[0027] Figure 4 A first kind of partial top view of the pole piece to be die cut in the die cutting process provided by the embodiment of the present application;

[0028] Figure 5 A structure schematic diagram of the pole piece provided by the embodiment of the present application;

[0029] Figure 6 A second kind of partial top view of the pole piece to be die cut in the die cutting process provided by the embodiment of the present application;

[0030] Figure 7 A third kind of partial top view of the pole piece to be die cut in the die cutting process provided by the embodiment of the present application;

[0031] Figure 8 A structure schematic diagram of the battery provided by the embodiment of the present application.

[0032] BRIEF DESCRIPTION OF DRAWINGS

[0033] 1-polar sheet to be die-cut; 100-coated area; 200-non-coated area; 11-foil; 12-active material; 13-tab; 2-polar sheet die-cutting device; 21-unwinding mechanism; 22-laser die-cutting mechanism; 23-slitting mechanism; 24-winding mechanism; 221-laser head; 241-winding roller; 3-polar sheet; 4-battery; 41-positive polar sheet; 42-negative polar sheet; 43-separator. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application. In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, the orientation words such as "upper" and "lower" generally refer to the upper and lower of the device in the actual use or working state, and specifically refer to the direction of the drawing surface in the drawings; and "inner" and "outer" refer to the contour of the device.

[0035] Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 ; wherein, Figure 1 is a structure schematic diagram of a polar sheet to be die-cut provided by the embodiments of the present application; Figure 2 is a structure schematic diagram of a polar sheet die-cutting device provided by the embodiments of the present application; Figure 3 is a flow chart of a polar sheet die-cutting method provided by the embodiments of the present application; Figure 4 is a first kind of partial top view schematic diagram of a polar sheet to be die-cut in a die-cutting process provided by the embodiments of the present application; Figure 5 is a structure schematic diagram of a polar sheet provided by the embodiments of the present application.

[0036] It should be noted that, Figure 4 shown is a top view schematic diagram in which the polar sheet to be die-cut does not appear belt breakage phenomenon and / or belt material phenomenon when the polar sheet to be die-cut is in a die-cutting process.

[0037] The embodiments of the present application provide a polar sheet die-cutting method, which comprises the following steps:

[0038] Step S10: providing a polar sheet to be die-cut 1, the surface of the polar sheet to be die-cut 1 having a coated area 100 and a non-coated area 200 located at least one side of the coated area 100, the polar sheet to be die-cut 1 comprising an active material 12 located in the coated area 100; as Figure 2as shown.

[0039] Specifically, the step S10 comprises the following steps:

[0040] Step S11: providing a foil 11, and dividing a coating area 100 and at least one non-coating area 200 on the surface of the foil 11.

[0041] In this embodiment, the surface of the foil 11 comprises two non-coating areas 200 and one coating area 100, and the coating area 100 is arranged between the two non-coating areas 200.

[0042] Step S12: coating an active substance 12 in the coating area 100 of the foil 11.

[0043] The foil 11 can be selected from one of an aluminum foil, a copper foil, a nickel foil or an iron foil, and the active substance 12 can be one of a positive electrode active substance and / or a negative electrode active substance. The material of the foil 11 and the specific type, composition and content of the active substance 12 are not specifically required and specially limited in this embodiment.

[0044] Specifically, in the step S12, the foil 11 comprises a first surface and a second surface arranged oppositely, and the active substance 12 can be coated on the first surface and / or the second surface of the foil 11.

[0045] Step S13: sequentially drying and rolling the foil 11 coated with the active substance 12, so that the active substance can be combined with the foil 11 firmly, and the to-be-die-cut electrode sheet 1 is obtained.

[0046] When the active substance 12 is coated on the first surface and the second surface of the foil 11, the same baking and rolling process can be used to process the active substance 12, so that the double-sided area density of the active substance 12 on the first surface and the second surface of the foil 11 is the same, to ensure the structural consistency and stability of the to-be-die-cut electrode sheet 1.

[0047] Step S20: obtaining the density characteristics of the active substance 12, and determining the die-cutting parameters of the to-be-die-cut electrode sheet 1 based on the correlation relationship 17≤(1000D+VF) / M≤20 between the density characteristics of the active substance 12 and the die-cutting parameters of the to-be-die-cut electrode sheet 1, wherein D is the compacted density of the active substance, V is the moving speed of the to-be-die-cut electrode sheet in the die-cutting process, F is the electrode sheet tension of the to-be-die-cut electrode sheet in the die-cutting process, and M is the single-sided area density of the active substance.

[0048] Specifically, the density characteristics of the active material 12 include a single-side area density of the active material 12, the single-side area density of the active material 12 being greater than or equal to 200 g / m 2 and less than or equal to 225 g / m 2 ; it can be understood that when the single-side area density of the active material 12 is low, the energy storage performance of the active material 12 cannot be fully exerted; when the active material 12 is too high, it can cause the expansion of the pole piece, the increase of ion diffusion resistance, and the reduction of electrochemical performance; by limiting the range of the single-side area density of the active material 12 to 200 g / m 2 to 225 g / m 2 , the embodiment balances the relationship between high energy density and pole piece performance, and can improve the electrochemical performance of the active material 12 on the basis of ensuring the density of the active material 12.

[0049] The density characteristics of the active material 12 also include the tap density of the active material 12, the tap density of the active material 12 being greater than or equal to 2.58 g / cm 3 and less than or equal to 2.62 g / cm 3 ; it can be understood that when the tap density of the active material 12 is low, the gap between the particles in the active material 12 is large, and it is difficult to meet the demand of high energy density; when the tap density of the active material 12 is too high, the particles in the active material 12 are excessively compressed, which can easily cause the mechanical performance of the pole piece to decrease, increase the risk of cracks, and affect the cycle life; by limiting the range of the tap density of the active material 12 to 2.58 g / cm 3 to 2.62 g / cm 3 , the embodiment ensures the close contact between the particles in the active material 12, improves the material utilization rate of the active material 12, enhances the mechanical stability of the pole piece, and meets the demand of high energy density at the same time.

[0050] It can be understood that by limiting the single-side area density of the active material 12 to be greater than or equal to 200 g / m 2 and less than or equal to 225 g / m 2 , and the tap density of the active material 12 to be greater than or equal to 2.58 g / cm 3 and less than or equal to 2.62 g / cm 3 , the embodiment realizes the high area density and high tap density of the structure of the to-be-die-cut pole piece 1, can not only improve the energy storage capacity in a unit area, but also can enhance the mechanical strength while ensuring the smoothness of the ion conduction path, thereby optimizing the electrochemical performance and stability of the die-cut pole piece 3, and meeting the requirements of high energy density battery production.

[0051] Further, the thickness of the to-be-die-cut tab 1 is greater than or equal to 165 microns and less than or equal to 198 microns. It can be understood that high specific energy tab has a larger compaction density and thickness, and when the thickness range exceeds a certain value, the laser power is difficult to fully penetrate the active material 12, which may result in incomplete cutting or cutting deformation. It can be understood that by limiting the thickness range of the to-be-die-cut tab 1 to 165 microns to 198 microns, it is ensured that the power of the laser die-cutting equipment can effectively penetrate the to-be-die-cut tab 1, thereby improving the die-cutting quality.

[0052] Specifically, the die-cutting parameters of the to-be-die-cut tab 1 include the moving speed of the to-be-die-cut tab 1 during the die-cutting process and the tab tension of the to-be-die-cut tab 1 during the die-cutting process. The moving speed of the to-be-die-cut tab 1 during the die-cutting process is greater than or equal to 30 m / min and less than or equal to 60 m / min. The tab tension of the to-be-die-cut tab 1 during the die-cutting process is greater than or equal to 100 N and less than or equal to 200 N. By reasonably controlling the moving speed and stress state of the to-be-die-cut tab 1 during the conveying and cutting process, the stability of the die-cutting process and the cutting quality can be ensured.

[0053] It can be understood that appropriate tab tension can avoid the to-be-die-cut tab 1 from being loose or too tight during the conveying process, thereby reducing the cutting deviation caused by the shaking or deviation of the to-be-die-cut tab 1. At the same time, the flatness of the surface of the to-be-die-cut tab 1 can be maintained, so that the to-be-die-cut tab 1 can be uniformly stressed during cutting, thereby reducing the cutting edge defects.

[0054] Step S30: Die-cutting the to-be-die-cut tab 1 in the non-coated area 200 according to the die-cutting parameters of the to-be-die-cut tab 1.

[0055] Specifically, in the step S30, the to-be-die-cut tab 1 is conveyed into the tab die-cutting device 2 according to the die-cutting parameters of the to-be-die-cut tab 1, and the to-be-die-cut tab 1 is die-cut by the tab die-cutting device 2 to form the tab 13 in the non-coated area 200.

[0056] In the step S30, the pole piece die-cutting device 2 comprises a unwinding mechanism 21, a laser die-cutting mechanism 22, a slitting mechanism 23 and a winding mechanism 24; the unwinding mechanism 21 is used to unwind the pole piece to be die-cut 1; the laser die-cutting mechanism 22 is used to die-cut the pole piece to be die-cut 1 to form the tab 13 in the non-coated area 200; the slitting mechanism 23 cuts the pole piece to be die-cut 1 which has been die-cut into small strips of different widths or sizes according to the requirements of pole piece design, forming individual pole pieces 3; the winding mechanism 24 is used to wind the pole pieces 3 after slitting, facilitating transportation and subsequent processing.

[0057] The pole piece die-cutting device 2 can be arranged in a production workshop with a temperature of 25±2℃, a humidity of <20% RH and a pressure of 101.3kpa. Such environmental conditions can effectively control the state of the material during the die-cutting process, avoid material deformation or performance fluctuations caused by changes in temperature and humidity, and ensure that the pole piece to be die-cut 1 remains highly stable during the die-cutting process.

[0058] Specifically, the step 30 can comprise the following steps:

[0059] Step S31: according to the die-cutting parameters of the pole piece to be die-cut 1, the laser die-cutting mechanism 22 is used to die-cut the pole piece to be die-cut 1 in the non-coated area 200 to form the tab 13.

[0060] The laser die-cutting mechanism 22 can comprise a single or two laser heads 221. When the laser die-cutting mechanism 22 comprises a single laser head 221, the laser die-cutting mechanism 22 can cut more accurately by concentrating energy at the focal point of the laser head 221. When two laser heads 221 are used to cut the pole piece to be die-cut 1 simultaneously, the processing efficiency can be greatly improved, achieving efficient cutting.

[0061] Further, the laser power of the laser die-cutting mechanism is greater than or equal to 120W and less than or equal to 240W. It should be noted that since the laser head 221 acts on the active substance 12 and the foil 11 simultaneously during the die-cutting process, accurate control of laser energy and cutting speed is crucial. If not properly controlled, it may seriously affect the die-cutting quality, causing the active substance 12 at the cutting edge to fall off, the appearance of strip material during the die-cutting process, or even causing a strip breakage failure.

[0062] It can be understood that the embodiment optimizes the laser die-cutting parameters, sets the laser power of the laser die-cuting mechanism to be greater than or equal to 120 W and less than or equal to 240 W, so as to ensure that the laser can cut through the active material 12 and the foil 11 without excessive ablation of the material; at the same time, by limiting the moving speed of the to-be-die-cut pole piece 1 to be greater than or equal to 30 m / min and less than or equal to 60 m / min, the cutting accuracy and production efficiency are balanced, and the incomplete cutting caused by the too fast moving speed of the to-be-die-cut pole piece 1 or the overheating problem caused by the too slow moving speed of the to-be-die-cut pole piece 1 is avoided, so as to effectively improve the processing stability and production yield of the to-be-die-cut pole piece 1 while ensuring the quality.

[0063] It can be understood that the embodiment adjusts the die-cutting parameters such as the pole piece tension of the to-be-die-cut pole piece 1, the moving speed of the to-be-die-cut pole piece 1, the compaction density of the active material 12, and the single-sided area density of the active material 12, so that the die-cutting parameters of the to-be-die-cut pole piece 1 satisfy the relationship formula 17≤(1000D+VF) / M≤20, thereby solving the strip and breakage problems of the to-be-die-cut pole piece 1 in the die-cutting process in the related art, and further improving the production efficiency and yield of the pole piece.

[0064] Step S32: conveying the to-be-die-cut pole piece 1 after die-cutting to a slitting mechanism 23, and the slitting mechanism 23 performs slitting on the to-be-die-cut pole piece 1 to form a pole piece 3.

[0065] Step S23: conveying the pole piece 3 after slitting to a winding mechanism 24, and using the winding mechanism 24 to wind the pole piece 3.

[0066] Specifically, the winding mechanism 24 includes at least two winding rollers 241, and each winding roller 241 is used to wind the pole piece 3 after slitting and die-cutting into a roll; it can be understood that the use of at least two winding rollers 241 can make the winding process more stable and efficient, thereby improving the production efficiency and reducing the waste or defective products caused by improper winding; at the same time, the configuration of the winding mechanism 24 can adjust the winding tension according to the production demand, so as to ensure that the tension of each roll of pole piece 3 is moderate, so as to facilitate subsequent transportation, storage and further processing.

[0067] The technical solutions of the embodiments of the application will be described in conjunction with specific embodiments.

[0068] Embodiment one

[0069] Please continue to combine Figure 1 , Figure 2 , Figure 3 and Figure 4The embodiment one provides a method for die cutting of pole piece, and the specific die cutting process has been described in detail in the above embodiment, which will not be repeated here. In the embodiment one, the die cutting parameters of the pole piece 1 to be die cut and the frequency of broken strip are shown in Table 1:

[0070] Table 1

[0071] Length of the to-be-die-cut pole piece / m Tension of the pole piece / N g / m2 2 ]] Compacted density / g / cm 3 ]] Moving speed / m / min Frequency of belt breakage Frequency of the strip Optimization rate of the pole piece 10000 50 220 2.6 30 0 0 99.29％

[0072] The die cutting parameters of the pole piece 1 to be die cut in Table 1 are brought into the relationship (1000D+VF) / M for calculation, and the result is (1000*2.6+30*50) / 220=18.6, which meets the requirement of the relationship: 17<18.6<20. In the die cutting process, by using the die cutting parameters given in Table 1, through calculation and debugging, the stability of the cutting process is successfully ensured, the frequency of broken strip of the pole piece 1 to be die cut is 0, the frequency of strip material is 0, and the yield of the pole piece after die cutting is 99.29%.

[0073] Embodiment two

[0074] Please continue to combine Figure 1 , Figure 2 , Figure 3 and Figure 4 . The embodiment two provides a method for die cutting of pole piece, and the specific die cutting process has been described in detail in the above embodiment, which will not be repeated here. In the embodiment two, the die cutting parameters of the pole piece 1 to be die cut and the frequency of broken strip are shown in Table 2:

[0075] Table 2

[0076] Length of the to-be-die-cut pole piece / m Tension of the pole piece / N Single sided area density / g / m 2 ]] Compacted density / g / cm 3 ]] Moving speed / m / min Frequency of belt breakage Frequency of the strip Optimization rate of the pole piece 10000 50 220 2.62 30 0 0 99.38％

[0077] The die cutting parameters of the pole piece 1 to be die cut in Table 2 are brought into the relationship (1000D+VF) / M for calculation, and the result is (1000*2.62+30*50) / 220=18.7, which meets the requirement of the relationship: 17<18.7<20. In the die cutting process, by using the die cutting parameters given in Table 2, through calculation and debugging, the stability of the cutting process is successfully ensured, the frequency of broken strip of the pole piece 1 to be die cut is 0, the frequency of strip material is 0, and the yield of the pole piece after die cutting is 99.38%.

[0078] Embodiment three

[0079] Please continue to combine Figure 1 , Figure 2 , Figure 3 and Figure 4Embodiment three provides a method for die cutting of the pole piece, and the specific die cutting process has been described in detail in the above embodiments, which will not be repeated here; wherein in the embodiment three, the die cutting parameters and the frequency of broken strips of the pole piece 1 to be die cut are shown in Table 3:

[0080] Table 3

[0081] Length of the to-be-die-cut pole piece / m Tension of the pole piece / N Single sided area density / g / m 2 ]]> Compacted density / g / cm 3 ]] Moving speed / m / min Frequency of belt breakage Frequency of the strip Optimization rate of the pole piece 10000 50 240 2.6 30 0 0 98.08％

[0082] The die cutting parameters of the pole piece 1 to be die cut in Table 3 are brought into the relationship formula (1000D+VF) / M for calculation, and the result is: (1000×2.6+30×50)240=17.1, and it meets the requirement of the relationship formula: 17<17.1<20; in the die cutting process, by using the die cutting parameters given in Table 3, through calculation and debugging, the stability of the cutting process is successfully ensured, the frequency of broken strips of the pole piece 1 to be die cut is 0, the frequency of strip material is 0, and the pole piece yield after die cutting is 98.08%.

[0083] Comparative example one

[0084] Please combine Figure 1 , Figure 2 , Figure 3 and Figure 6 ; wherein, Figure 6 is a second partial top view schematic diagram of the pole piece to be die cut in the die cutting process provided by the embodiments of the present application; it should be noted that, Figure 6 shown is a top view schematic diagram of the pole piece to be die cut in the die cutting process, wherein due to improper die cutting parameters or improper control, irregular cutting edges or broken phenomenon occurs in the cutting process.

[0085] Comparative example one provides a method for die cutting of the pole piece, and the specific die cutting process has been described in detail in the above embodiments, which will not be repeated here; wherein in the comparative example one, the die cutting parameters and the frequency of broken strips of the pole piece 1 to be die cut are shown in Table 4:

[0086] Table 4

[0087] Length of the to-be-die-cut pole piece / m Tension of the pole piece / N g / m2 2 ]]> Compacted density / g / cm 3 ]]> Moving speed / m / min Frequency of belt breakage Optimization rate of the pole piece 10000 80 220 2.6 30 9 96.06％

[0088] The die cutting parameters of the pole piece 1 to be die cut in Table 4 are brought into the relationship formula (1000D+VF) / M for calculation, and the result is: (1000×2.6+30×80)220=22.7, and it does not meet the requirement of the relationship formula: 20<22.7; in the die cutting process, by using the die cutting parameters given in Table 4, the frequency of broken strips of the pole piece 1 to be die cut is 9, and the pole piece yield after die cutting is 96.06%.

[0089] Comparative example two

[0090] Please continue to combine Figure 1 , Figure 2 , Figure 3 and Figure 6 ; the second comparative example provides a method for die cutting the pole piece, and the specific die cutting process has been described in detail in the above examples, which will not be repeated here; wherein in the first comparative example, the die cutting parameters of the to-be-die-cut pole piece 1 and the belt breaking frequency are shown in Table 5:

[0091] Table 5

[0092] Length of the to-be-die-cut pole piece / m Tension of the pole piece / N Single sided area density / g / m 2 ]]> Compacted density / g / cm 3 ]]> Moving speed / m / min Frequency of belt breakage Optimization rate of the pole piece 10000 50 220 2.6 60 12 95.08％

[0093] The die cutting parameters of the to-be-die-cut pole piece 1 in Table 5 are brought into the relationship formula (1000D+VF) / M for calculation, and the result is: (1000*2.6+60*50) / 220=25.5, and it does not meet the requirement of the relationship formula: 20<25.5; in the die cutting process, using the die cutting parameters given in Table 5, the belt breaking frequency of the to-be-die-cut pole piece 1 is 12, and the pole piece yield after die cutting is 95.08%.

[0094] It should be noted that in the above example one, example two, example three, comparative example one and comparative example two, the thickness of the to-be-die-cut pole piece, the width of the to-be-die-cut pole piece, the laser power of the laser die cutting mechanism and other data are the same, consistent, so as to ensure the fair comparison between the examples, and to exclude the interference of external factors on the die cutting quality, so that the effect of the pole piece die cutting method is truly and effectively verified; wherein the selection of these parameters can be determined according to the actual production process, equipment performance and operating conditions, and the relevant parameters can be adjusted according to experience and actual test results to ensure the stability of the die cutting process and the quality of the final pole piece, that is, this embodiment does not make specific limitations.

[0095] It can be understood that, as can be seen from the above example one, example two, example three, comparative example one and comparative example two, when (1000D+VF) / M>20, the pole piece tension of the to-be-die-cut pole piece 1 or the moving speed of the to-be-die-cut pole piece 1 is too high, the laser cutting stress exceeds the bearing range of the to-be-die-cut pole piece 1, which is easy to cause belt breaking; by adjusting the die cutting parameters of the to-be-die-cut pole piece 1 to meet the relationship formula 17≤(1000D+VF) / M≤20, the compaction density and single-sided area density of the active substance 12 are sufficient, and the pole piece tension of the to-be-die-cut pole piece 1 and the moving speed of the to-be-die-cut pole piece 1 are within a reasonable range, avoiding excessive mechanical stress, thereby preventing the risk of belt breaking of the to-be-die-cut pole piece 1 and improving the pole piece yield.

[0096] Comparative Example Three

[0097] Please combine Figure 1 , Figure 2 , Figure 3 and Figure 7 ; wherein, Figure 7 is a third kind of partial top view schematic diagram of the to-be-die-cut pole piece in a die-cutting process provided by the embodiments of the present application; it should be noted that, Figure 7 shown is a top view schematic diagram of the to-be-die-cut pole piece appearing a strip phenomenon in the die-cutting process of the to-be-die-cut pole piece; wherein, due to improper die-cutting parameters or insufficient control, an irregular wavy edge phenomenon appears in the cutting process.

[0098] Example three provides a method for die-cutting a pole piece, and the specific die-cutting process has been described in detail in the above embodiments, which will not be repeated here; wherein, in the example three, the die-cutting parameters and the strip frequency of the to-be-die-cut pole piece 1 are shown in Table 6:

[0099] Table 6

[0100] Length of the to-be-die-cut pole piece / m Tension of the pole piece / N Single sided area density / g / m 2 ]]> Compacted density / g / cm 3 ]] Moving speed / m / min Frequency of the strip Optimization rate of the pole piece 10000 40 240 2.6 30 6 95.64％

[0101] The die-cutting parameters of the to-be-die-cut pole piece 1 in Table 6 are brought into the relationship formula (1000D+VF) / M for calculation, and the result is: (1000x2.6+30x40)240=15.8, and it does not meet the requirement of the relationship formula: 15.8<17; in the die-cutting process, using the die-cutting parameters given in Table 6, the strip frequency of the to-be-die-cut pole piece 1 is 6, and the pole piece yield after die-cutting is 95.64%.

[0102] Example four

[0103] Please continue to combine Figure 1 , Figure 2 , Figure 3 and Figure 7 ; Example four provides a method for die-cutting a pole piece, and the specific die-cutting process has been described in detail in the above embodiments, which will not be repeated here; wherein, in the example four, the die-cutting parameters and the strip frequency of the to-be-die-cut pole piece 1 are shown in Table 7:

[0104] Table 7

[0105] Length of the to-be-die-cut pole piece / m Tension of the pole piece / N g / m2 2 ]] Compacted density / g / cm 3 ]] Moving speed / m / min Frequency of the strip Optimization rate of the pole piece 10000 40 240 2.58 30 8 94.98％

[0106] The die-cutting parameters of the to-be-die-cut pole piece 1 in Table 7 are brought into the relationship formula (1000D+VF) / M for calculation, and the result is: (1000x2.58+30x40)240=15.8, and it does not meet the requirement of the relationship formula: 15.8<17; in the die-cutting process, using the die-cutting parameters given in Table 7, the strip frequency of the to-be-die-cut pole piece 1 is 8, and the pole piece yield after die-cutting is 94.98%.

[0107] It should be noted that in the above embodiment one, embodiment two, embodiment three, comparative example three and comparative example four, the thickness of the to-be-die-cut pole piece, the width of the to-be-die-cut pole piece, the laser power of the laser die-cutting mechanism and other data are the same, consistent, thereby ensuring the fair comparison between the embodiments, excluding external factors that interfere with the die-cutting quality, so that the effect of the pole piece die-cutting method is truly and effectively verified; wherein the selection of these parameters can be determined according to the actual production process, equipment performance and operating conditions, and the relevant parameters can be adjusted according to experience and actual test results to ensure the stability of the die-cutting process and the quality of the final pole piece, that is, the present embodiment does not make specific limitations.

[0108] It can be understood that in combination with the above embodiment one, embodiment two, embodiment three, comparative example three and comparative example four, when (1000D+VF) / M<17, the compaction density of the active substance 12 is insufficient or the single-sided area density of the active substance 12 is insufficient, the pole piece tension of the to-be-die-cut pole piece 1 is too low or the moving speed of the to-be-die-cut pole piece 1 is too low, which is easy to cause the die-cutting pole piece to have obvious wavy edges, resulting in incomplete cutting and die-cutting strip phenomenon; by adjusting the die-cutting parameters of the to-be-die-cut pole piece 1, so that it satisfies the relationship 17≤(1000D+VF) / M≤20, the compaction density and single-sided area density of the active substance 12 are sufficient, and the pole piece tension of the to-be-die-cut pole piece 1 and the moving speed of the to-be-die-cut pole piece 1 are within a reasonable range, thereby reducing the wavy edges of the die-cutting pole piece and avoiding the risk of die-cutting strip, and improving the pole piece yield.

[0109] Please refer to Figure 8 The structure schematic diagram of the battery provided in the embodiments of the present application.

[0110] The embodiments also provide a battery 4, which comprises a positive pole piece 41, a negative pole piece 42 and a separator 43 arranged between the positive pole piece 41 and the negative pole piece 42; wherein at least one of the positive pole piece 41 and the negative pole piece 42 can adopt the pole piece die-cutting method described in any of the above embodiments.

[0111] Specifically, the positive pole piece 41, the negative pole piece 42 and the separator 43 can be used to construct a stacked cell or a wound cell, and the battery 4 includes but is not limited to one of a soft package battery, a square battery or a cylindrical battery.

[0112] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0113] The above describes in detail the die cutting method of the pole piece, the pole piece and the battery provided by the embodiment. The principles and implementation manners of the present application are described by using specific examples. The above embodiment is only used to help understand the method and the core idea of the present application. Meanwhile, for those skilled in the art, the specific implementation manners and application ranges will be changed according to the idea of the present application. In conclusion, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A method of die cutting a pole piece, characterized by, The application relates to a battery and a method for manufacturing a battery. Providing a to-be-die-cut electrode sheet, a surface of the to-be-die-cut electrode sheet is provided with a coated area and a non-coated area located on at least one side of the coated area, the to-be-die-cut electrode sheet comprises an active substance located in the coated area; The density characteristic of the active substance is obtained, and the die-cutting parameters of the die-cutting sheet are determined based on the correlation between the density characteristic of the active substance and the die-cutting parameters of the die-cutting sheet, 17≤(1000D+VF) / M≤20, wherein D is the compacted density of the active substance, the compacted density is greater than or equal to 2.58 g / cm 3 , and less than or equal to 2.62 g / cm 3 ; V is the moving speed of the die-cutting sheet during the die-cutting process, the moving speed is greater than or equal to 30 m / min, and less than or equal to 60 m / min; F is the sheet tension of the die-cutting sheet during the die-cutting process, the sheet tension is greater than or equal to 100 N, and less than or equal to 200 N; and M is the single-side area density of the active substance, the single-side area density is greater than or equal to 200 g / m 2 , and less than or equal to 225 g / m 2 . Die-cutting the to-be-die-cut electrode sheet in the non-coated area according to die-cutting parameters of the to-be-die-cut electrode sheet.

2. The method of die cutting pole pieces according to claim 1, wherein, The thickness of the to-be-die-cut electrode sheet is greater than or equal to 165 microns and less than or equal to 198 microns.

3. The method of die cutting a pole piece according to any one of claims 1 to 2, wherein, The step of die-cutting the to-be-die-cut electrode sheet in the non-coated area according to the die-cutting parameters of the to-be-die-cut electrode sheet comprises: Die-cutting the to-be-die-cut electrode sheet in the non-coated area by using a laser die-cutting mechanism to form an electrode lug; Conveying the die-cut to-be-die-cut electrode sheet to a slitting mechanism, and slitting the to-be-die-cut electrode sheet by using the slitting mechanism; Conveying the slitted electrode sheet to a winding mechanism, and winding the electrode sheet by using the winding mechanism.

4. A pole piece characterized by, The electrode sheet is obtained by using the die-cutting method of the electrode sheet in any one of claims 1 to 3.

5. A battery, characterized by The battery comprises the electrode sheet in claim 4.

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