Die cutting method of pole piece, pole piece and battery

Abstract

The invention provides a die cutting method of a pole piece, the pole piece and a battery, the die cutting method of the pole piece comprises the following steps: providing a to-be-die-cut pole piece and a laser die cutting device, the surface of the to-be-die-cut pole piece is provided with a coating area and a non-coating area located on at least one side of the coating area, and the to-be-die-cut pole piece comprises an active substance located in the coating area; the density characteristic of the active substance is obtained, and the die cutting parameters of the to-be-die-cut pole piece are determined based on the incidence relation between the density characteristic of the active substance and the die cutting parameters of the to-be-die-cut pole piece; according to the die cutting parameters of the to-be-die-cut pole piece, the to-be-die-cut pole piece in the non-coating area is subjected to die cutting, the problems of material carrying and belt breakage in the die cutting process of the pole piece in the prior art are solved, and the production efficiency and the yield of the pole piece are improved by optimizing the relation between the die cutting parameters and the density characteristics of the active material.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a pole piece die-cutting method, a pole piece and a battery. Background Art

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

[0003] During the production process of high-energy-density batteries, the laser cutting machine focuses the laser beam to a focal area to form a cutting focus. In the focal area, the laser power is maximum and the cutting effect is best. Beyond the range of the cutting focus, the laser power decays with increasing distance, resulting in incomplete cutting of the foil portion far from the cutting focus. This causes high-energy-density batteries to be prone to die-cutting strips or broken strips during processing, affecting production efficiency and product quality. Summary of the invention

[0004] The embodiments of the present application provide a method for die-cutting a pole piece, a pole piece, and a battery, so as to solve or at least partially solve the deficiencies of the above-mentioned background technology.

[0005] In a first aspect, an embodiment of the present application provides a method for die-cutting a pole piece, comprising:

[0006] Providing a pole piece to be die-cut, wherein the surface of the pole piece to be die-cut has a coating area and a non-coating area located at least on one side of the coating area, and the pole piece to be die-cut includes an active material located in the coating area;

[0007] The density characteristics of the active material are obtained, and based on the correlation relationship between the density characteristics of the active material and the die-cutting parameters of the electrode piece to be die-cut 17≤(1000D+VF) / M≤20, the die-cutting parameters of the electrode piece to be die-cut are determined, wherein D is the compaction density of the active material; V is the moving speed of the electrode piece to be die-cut during the die-cutting process; F is the electrode tension of the electrode piece to be die-cut during the die-cutting process; M is the single-sided surface density of the active material;

[0008] The pole piece to be die-cut in the non-coating area is die-cut according to the die-cutting parameters of the pole piece to be die-cut.

[0009] In one embodiment, the density characteristics of the active material include the compacted density of the active material and the single-surface density of the active material;

[0010] The die-cutting parameters of the pole piece to be die-cut include the moving speed of the pole piece to be die-cut during the die-cutting process, and the pole piece tension of the pole piece to be die-cut during the die-cutting process.

[0011] In one embodiment, the pole piece tension of the pole piece 1 to be die-cut during the die-cutting process is greater than or equal to 100N and less than or equal to 200N.

[0012] In one embodiment, the single-sided surface density of the active material is greater than or equal to 200 g / m 2 , and less than or equal to 225g / m 2 .

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

[0014] In one embodiment, the moving speed of the electrode piece to be die-cut during the die-cutting process is greater than or equal to 30 m / min and less than or equal to 60 m / min.

[0015] In one embodiment, the thickness of the pole piece to be die-cut is greater than or equal to 165 microns and less than or equal to 198 microns.

[0016] In one embodiment, the step of die-cutting the electrode piece to be die-cut in the non-coating area according to the die-cutting parameters of the electrode piece to be die-cut comprises:

[0017] Using a laser die-cutting mechanism to die-cut the electrode piece to be die-cut in the non-coating area to form a pole ear;

[0018] The die-cutting electrode piece to be die-cut is transferred to a stripping mechanism, and the stripping mechanism strips the electrode piece to be die-cut;

[0019] The stripped pole piece is transferred to a winding mechanism, and the winding mechanism is used to wind up the pole piece.

[0020] In a second aspect, an embodiment of the present application provides a pole piece, which is obtained by using the pole piece die-cutting method described in the first aspect.

[0021] In a third aspect, an embodiment of the present application provides a battery, comprising the pole piece described in the second aspect.

[0022] Beneficial effects of the embodiments of the present application: The embodiments of the present application provide a pole piece die-cutting method, a pole piece and a battery, the pole piece die-cutting method comprising 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 having a coating area and a non-coating area located on at least one side of the coating area, the pole piece to be die-cut comprises an active material located in the coating area; obtaining the density characteristics of the active material, and determining the die-cutting parameters of the pole piece to be die-cut based on the correlation between the density characteristics of the active material and the die-cutting parameters of the pole piece to be die-cut; according to the die-cutting parameters of the pole piece to be die-cut, die-cutting the pole piece to be die-cut in the non-coating area, the method solves the problems of stripping and strip breaking in the pole piece die-cutting process in the prior art, and improves the production efficiency and yield rate of the pole piece by optimizing the relationship between the die-cutting parameters and the density characteristics of the active material. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution in this embodiment, the drawings required for use in the description of the embodiment will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

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

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

[0026] Figure 3 A flow chart of a pole piece die cutting method provided in an embodiment of the present application;

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

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

[0029] Figure 6 A second partial top view of the electrode to be die-cut provided in the embodiment of the present application during the die-cutting process;

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

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

[0032] Description of Reference Numerals

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

[0034] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods 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, unless otherwise stated, the directional words such as "upper" and "lower" used generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inside" and "outside" refer to the outline of the device.

[0035] Please combine Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 ;in, Figure 1 A schematic diagram of the structure of the electrode piece to be die-cut provided in the embodiment of the present application; Figure 2 A schematic diagram of the structure of a pole piece die-cutting device provided in an embodiment of the present application; Figure 3 A flow chart of a pole piece die cutting method provided in an embodiment of the present application; Figure 4 A first partial top view schematic diagram of a pole piece to be die-cut in a die-cutting process provided in an embodiment of the present application; Figure 5 A schematic diagram of the structure of the pole piece provided in an embodiment of the present application.

[0036] It should be noted that Figure 4 The figure shows a top view schematically showing that when the electrode piece to be die-cut is undergoing a die-cutting process, the electrode piece to be die-cut does not have a tape breakage phenomenon and / or a material carrying phenomenon.

[0037] This embodiment provides a die-cutting method for a pole piece, comprising the following steps:

[0038] Step S10: providing a pole piece 1 to be die-cut, wherein the surface of the pole piece 1 to be die-cut has a coating area 100 and a non-coating area 200 located at least on one side of the coating area 100, and the pole piece 1 to be die-cut includes an active material 12 located in the coating area 100; Figure 2shown.

[0039] Specifically, step S10 includes 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 a surface of the foil 11 .

[0041] In this embodiment, the technical solution of the present application is illustrated by taking the case where the surface of the foil 11 includes two non-coated areas 200 and one coated area 100 , and the coated area 100 is arranged between the two non-coated areas 200 .

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

[0043] The foil 11 can be one of aluminum foil, copper foil, nickel foil or iron foil, and the active substance 12 can be one of positive electrode active substances and / or negative electrode active substances. This embodiment does not make specific requirements or special limitations on the material of the foil 11 and the specific type, component and content of the active substance 12.

[0044] Specifically, in the step S12 , the foil 11 includes a first surface and a second surface that are opposite to each other, and the active material 12 may be coated on the first surface and / or the second surface of the foil 11 .

[0045] Step S13: drying and rolling the foil 11 coated with the active material 12 in sequence, so that the active material can be firmly combined with the foil 11, thereby obtaining the electrode piece 1 to be die-cut.

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

[0047] Step S20: Obtain the density characteristics of the active material 12, and determine the die-cutting parameters of the electrode piece 1 to be die-cut based on the correlation relationship 17≤(1000D+VF) / M≤20 between the density characteristics of the active material 12 and the die-cutting parameters of the electrode piece 1 to be die-cut, wherein D is the compaction density of the active material; V is the moving speed of the electrode piece to be die-cut during the die-cutting process; F is the electrode tension of the electrode piece to be die-cut during the die-cutting process; and M is the single-sided surface density of the active material.

[0048] Specifically, the density characteristics of the active material 12 include the single-sided surface density of the active material 12, and the single-sided surface density of the active material 12 is greater than or equal to 200 g / m 2 , and less than or equal to 225g / m 2 It is understandable that when the single-sided surface density of the active material 12 is low, the energy storage performance of the active material 12 cannot be fully utilized; when the active material 12 is too high, it may cause the pole piece to expand, increase the ion diffusion resistance, and reduce the electrochemical performance; this embodiment limits the single-sided surface density of the active material 12 to 200g / m 2 Up to 225g / m 2 , which balances the relationship between high energy density and electrode performance, and can improve the electrochemical performance of the active material 12 while ensuring the density of the active material 12.

[0049] The density characteristic of the active material 12 is also the compaction density of the active material 12, and the compaction density of the active material 12 is greater than or equal to 2.58 g / cm 3 , and less than or equal to 2.62g / cm 3 It can be understood that when the compaction density of the active material 12 is low, the gaps between the particles in the active material 12 are large, and it is difficult to meet the requirements of high energy density; when the compaction density of the active material 12 is low, the particles in the active material 12 are over-compressed, which can easily lead to a decrease in the mechanical properties of the pole piece, increase the risk of cracks, and affect the cycle life; this embodiment limits the compaction density of the active material 12 to 2.58 g / cm 3 Up to 2.62g / cm 3 , thereby ensuring close contact between particles in the active material 12, improving the material utilization of the active material 12, enhancing the mechanical stability of the electrode, and meeting the high energy density requirements.

[0050] It is understandable that in this embodiment, the single-surface density of the active material 12 is limited to be greater than or equal to 200 g / m 2 , and less than or equal to 225g / m 2 The compacted density of the active material 12 is greater than or equal to 2.58 g / cm 3 , and less than or equal to 2.62g / cm 3 , thereby achieving a high surface density and high compactness of the structure of the electrode piece 1 to be die-cut, which can not only improve the energy storage capacity per unit area, but also enhance the mechanical strength while ensuring the smoothness of the ion conduction path, thereby optimizing the electrochemical performance and stability of the electrode piece 3 after die-cutting, and meeting the requirements of high energy density battery production.

[0051] Furthermore, the thickness of the pole piece 1 to be die-cut is greater than or equal to 165 microns and less than or equal to 198 microns. It can be understood that the high specific energy pole piece has a larger compaction density and thickness. When the thickness range exceeds a certain value, the laser power is difficult to fully penetrate the active material 12, which may cause incomplete cutting or cutting deformation; it can be understood that this embodiment limits the thickness range of the pole piece 1 to be die-cut to 165 microns to 198 microns, thereby ensuring that the power of the laser die-cutting equipment can effectively penetrate the pole piece 1 to be die-cut, thereby improving the die-cutting quality.

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

[0053] It can be understood that appropriate electrode tension can prevent the electrode 1 to be die-cut from becoming loose or too tight during the transmission process, thereby reducing the cutting deviation caused by the shaking or deviation of the electrode 1 to be die-cut; at the same time, it can maintain the flatness of the surface of the electrode 1 to be die-cut, so that the electrode 1 to be die-cut can be evenly stressed during cutting, reducing edge defects.

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

[0055] Specifically, in the step S30, according to the die-cutting parameters of the pole piece 1 to be die-cut, the pole piece 1 to be die-cut is transferred to the pole piece die-cutting device 2, and the pole piece die-cutting device 2 is used to die-cut the pole piece 1 to form the pole ear 13 located in the non-coating area 200.

[0056] In the step S30, the pole piece die-cutting device 2 includes an unwinding mechanism 21, a laser die-cutting mechanism 22, a stripping mechanism 23 and a winding mechanism 24; the unwinding mechanism 21 is used to unwind the pole piece 1 to be die-cut; the laser die-cutting mechanism 22 is used to die-cut the pole piece 1 to be die-cut to form a pole ear 13 located in the non-coating area 200; the stripping mechanism 23 cuts the pole piece 1 to be die-cut that has been die-cut into small strips of different widths or sizes according to the requirements of the pole piece design to form a separate pole piece 3; the winding mechanism 24 is used to wind up the stripped pole piece 3 to facilitate transportation and subsequent processing.

[0057] The pole piece die-cutting device 2 can be set in a production workshop with a temperature of 25±2°C, 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 1 to be die-cut maintains a high degree of stability during the die-cutting process.

[0058] Specifically, the step 30 may include the following steps:

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

[0060] The laser die-cutting mechanism 22 may include a single or two laser heads 221. When the laser die-cutting mechanism 22 includes a single laser head 221, the laser die-cutting mechanism 22 can concentrate energy at the focus of the laser head 221 for cutting, and can process the electrode piece 1 to be die-cut more accurately; when two laser heads 221 are used to cut the electrode piece 1 to be die-cut at the same time, the processing efficiency can be greatly improved to achieve efficient cutting.

[0061] Furthermore, 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 material 12 and the foil 11 simultaneously during the die-cutting process, precise control of the laser energy and the cutting movement speed is crucial. If improperly controlled, the die-cutting quality may be seriously affected, resulting in the active material 12 at the cutting edge falling off, the occurrence of material carrying during the die-cutting process, and even causing a broken tape failure.

[0062] It can be understood that this embodiment optimizes the laser die-cutting parameters and sets the laser power of the laser die-cutting mechanism to be greater than or equal to 120W and less than or equal to 240W, thereby ensuring that the laser can cut through the active material 12 and the foil 11 and will not excessively ablate the material; at the same time, by limiting the moving speed of the electrode piece 1 to be die-cut to be greater than or equal to 30m / min and less than or equal to 60m / min, the cutting accuracy and production efficiency are balanced to avoid incomplete cutting due to the excessively fast moving speed of the electrode piece 1 to be die-cut, or overheating due to the excessively slow moving speed of the electrode piece 1 to be die-cut, thereby effectively improving the processing stability and production yield of the electrode piece 1 to be die-cut while ensuring the quality.

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

[0064] Step S32: The die-cutting-completed electrode piece 1 is transferred to the slitting mechanism 23 , and the slitting mechanism 23 slits the electrode piece 1 to be die-cut to form electrode pieces 3 .

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

[0066] Specifically, the winding mechanism 24 includes at least two winding rollers 241, each of which is used to wind the pole piece 3 that has been stripped and die-cut into a roll; it can be understood that in this embodiment, by using at least two winding rollers 241, the winding process can be carried out more smoothly and efficiently, thereby improving production efficiency and reducing 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 production needs, ensuring 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 solution of the embodiment of the present application is now described in conjunction with specific embodiments.

[0068] Embodiment 1

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

[0070] Table 1

[0071] Length of the electrode to be die-cut / m Pole tension / N <![CDATA[Grammage per single side / g / m 2 > <![CDATA[Compaction density / g / cm 3 > Moving speed / m / min Belt break frequency Frequency of bringing materials Pole superiority rate 10000 50 220 2.6 30 0 0 99.29％

[0072] The die-cutting parameters of the electrode piece 1 to be die-cut in Table 1 are substituted into the relationship (1000D+VF) / M for calculation, and the result is: (1000×2.6+30×50)220=18.6, and it meets the requirements of the relationship: 17<18.6<20; in the die-cutting process, the die-cutting parameters given in Table 1 are used. After calculation and debugging, the stability of the cutting process is successfully guaranteed, ensuring that the tape break frequency of the electrode piece 1 to be die-cut is 0, the material carrying frequency is 0, and the excellent rate of the electrode piece after die-cutting is 99.29%.

[0073] Embodiment 2

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

[0075] Table 2

[0076] Length of the electrode to be die-cut / m Pole tension / N <![CDATA[Single-sided areal density / g / m 2 > <![CDATA[Compaction density / g / cm 3 > Moving speed / m / min Belt break frequency Frequency of bringing materials Pole superiority rate 10000 50 220 2.62 30 0 0 99.38％

[0077] The die-cutting parameters of the electrode piece 1 to be die-cut in Table 2 are substituted into the relationship (1000D+VF) / M for calculation, and the result is: (1000×2.62+30×50)220=18.7, and it meets the requirements of the relationship: 17<18.7<20; in the die-cutting process, the die-cutting parameters given in Table 2 are used. After calculation and debugging, the stability of the cutting process is successfully guaranteed, ensuring that the tape break frequency of the electrode piece 1 to be die-cut is 0, the material carrying frequency is 0, and the excellent rate of the electrode piece after die-cutting is 99.38%.

[0078] Embodiment 3

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

[0080] Table 3

[0081] Length of the electrode to be die-cut / m Pole tension / N <![CDATA[Grammage per side / g / m 2 > <![CDATA[Compaction density / g / cm 3 > Moving speed / m / min Belt break frequency Frequency of bringing materials Pole superiority rate 10000 50 240 2.6 30 0 0 98.08％

[0082] The die-cutting parameters of the electrode piece 1 to be die-cut in Table 3 are substituted into the relationship (1000D+VF) / M for calculation, and the result is: (1000×2.6+30×50)240=17.1, and it meets the requirements of the relationship: 17<17.1<20; in the die-cutting process, the die-cutting parameters given in Table 3 are adopted. After calculation and debugging, the stability of the cutting process is successfully guaranteed, ensuring that the tape break frequency of the electrode piece 1 to be die-cut is 0, the material carrying frequency is 0, and the excellent rate of the electrode piece after die-cutting is 98.08%.

[0083] Comparative Example 1

[0084] Please combine Figure 1 , Figure 2 , Figure 3 and Figure 6 ;in, Figure 6 The second partial top view schematic diagram of the electrode to be die-cut in the die-cutting process provided in the embodiment of the present application; it should be noted that, Figure 6 The figure shows a top view schematic diagram of a broken strip of the electrode piece to be die-cut during the die-cutting process; wherein, due to improper die-cutting parameters or lax control, irregular cutting edges or breaks occur during the cutting process.

[0085] Comparative Example 1 provides a method for die-cutting a pole piece. The specific die-cutting process has been described in detail in the above embodiment and will not be repeated here. In the comparative example 1, the die-cutting parameters and the frequency of tape breakage of the pole piece 1 to be die-cut are shown in Table 4:

[0086] Table 4

[0087] Length of the electrode to be die-cut / m Pole tension / N <![CDATA[Grammage per side / g / m 2 > <![CDATA[Compaction density / g / cm 3 > Moving speed / m / min Belt break frequency Pole superiority rate 10000 80 220 2.6 30 9 96.06％

[0088] The die-cutting parameters of the electrode piece 1 to be die-cut in Table 4 are substituted into the relationship (1000D+VF) / M for calculation, and the result is: (1000×2.6+30×80)220=22.7, which does not meet the requirement of the relationship: 20<22.7; During the die-cutting process, the die-cutting parameters given in Table 4 are used, the tape breakage frequency of the electrode piece 1 to be die-cut is 9, and the electrode piece quality rate after die-cutting is 96.06%.

[0089] Comparative Example 2

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

[0091] Table 5

[0092] Length of the electrode to be die-cut / m Pole tension / N <![CDATA[Single-sided areal density / g / m 2 > <![CDATA[Compaction density / g / cm 3 > Moving speed / m / min Belt break frequency Pole superiority rate 10000 50 220 2.6 60 12 95.08％

[0093] The die-cutting parameters of the electrode piece 1 to be die-cut in Table 5 are substituted into the relationship (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: 20<25.5; during the die-cutting process, the die-cutting parameters given in Table 5 are used, the tape breakage frequency of the electrode piece 1 to be die-cut is 12, and the electrode piece quality rate after die-cutting is 95.08%.

[0094] It should be noted that in the above-mentioned Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2, the thickness of the pole piece to be die-cut, the width of the pole piece to be die-cut, the laser power of the laser die-cutting mechanism and other data are the same and remain consistent, thereby ensuring a fair comparison between the various embodiments, eliminating the interference of external factors on the die-cutting quality, and making the effect of the die-cutting method of the pole piece 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 according to different production requirements, 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 restrictions on this.

[0095] It can be understood that, in combination with the above-mentioned Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2, it can be known that when (1000D+VF) / M>20, the pole piece tension of the pole piece 1 to be die-cut or the moving speed of the pole piece 1 to be die-cut is too high, and the laser cutting stress exceeds the bearing range of the pole piece 1 to be die-cut, which easily leads to tape breakage; by adjusting the die-cutting parameters of the pole piece 1 to be die-cut so that it satisfies the relationship 17≤(1000D+VF) / M≤20, the compaction density and single-sided surface density of the active material 12 are sufficient, the pole piece tension of the pole piece 1 to be die-cut and the moving speed of the pole piece 1 to be die-cut are within a reasonable range, and excessive mechanical stress is avoided, thereby preventing the risk of tape breakage of the pole piece 1 to be die-cut and improving the quality rate of the pole piece.

[0096] Comparative Example 3

[0097] Please combine Figure 1 , Figure 2 , Figure 3 and Figure 7 ;in, Figure 7 The third partial top view of the electrode to be die-cut in the die-cutting process provided in the embodiment of the present application; it should be noted that, Figure 7 The figure shows a schematic top view of the pole piece to be die-cut having a material carrying phenomenon during the die-cutting process of the pole piece to be die-cut; wherein, due to improper die-cutting parameters or lax control, irregular wavy edges appear during the cutting process.

[0098] Comparative Example 3 provides a method for die-cutting a pole piece. The specific die-cutting process has been described in detail in the above embodiment and will not be repeated here. In the comparative example 3, the die-cutting parameters and the frequency of the stripping of the pole piece 1 to be die-cut are shown in Table 6:

[0099] Table 6

[0100] Length of the electrode to be die-cut / m Pole tension / N <![CDATA[Grammage per side / g / m 2 > <![CDATA[Compaction density / g / cm 3 > Moving speed / m / min Frequency of bringing materials Pole superiority rate 10000 40 240 2.6 30 6 95.64％

[0101] The die-cutting parameters of the electrode piece 1 to be die-cut in Table 6 are substituted into the relationship (1000D+VF) / M for calculation, and the result is: (1000×2.6+30×40)240=15.8, and it does not meet the requirement of the relationship: 15.8<17; During the die-cutting process, the die-cutting parameters given in Table 6 are used, the material frequency of the electrode piece 1 to be die-cut is 6, and the electrode piece quality rate after die-cutting is 95.64%.

[0102] Comparative Example 4

[0103] Please continue to combine Figure 1 , Figure 2 , Figure 3 and Figure 7 ; Comparative Example 4 provides a method for die-cutting a pole piece, and the specific die-cutting process has been described in detail in the above embodiment, and will not be repeated here; wherein, in the comparative example 4, the die-cutting parameters and the frequency of the stripping of the pole piece 1 to be die-cut are shown in Table 7:

[0104] Table 7

[0105] Length of the electrode to be die-cut / m Pole tension / N <![CDATA[Grammage per side / g / m 2 > <![CDATA[Compaction density / g / cm 3 > Moving speed / m / min Frequency of bringing materials Pole superiority rate 10000 40 240 2.58 30 8 94.98％

[0106] The die-cutting parameters of the electrode piece 1 to be die-cut in Table 7 are substituted into the relationship (1000D+VF) / M for calculation, and the result is: (1000×2.58+30×40)240=15.8, and it does not meet the requirement of the relationship: 15.8<17; during the die-cutting process, the die-cutting parameters given in Table 7 are used, the material frequency of the electrode piece 1 to be die-cut is 8, and the electrode piece quality rate after die-cutting is 94.98%.

[0107] It should be noted that in the above-mentioned Example 1, Example 2, Example 3, Comparative Example 3 and Comparative Example 4, the thickness of the pole piece to be die-cut, the width of the pole piece to be die-cut, the laser power of the laser die-cutting mechanism and other data are the same and remain consistent, thereby ensuring a fair comparison between the embodiments, eliminating the interference of external factors on the die-cutting quality, and making the effect of the die-cutting method of the pole piece 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 according to different production requirements, 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 restrictions on this.

[0108] It can be understood that, in combination with the above-mentioned Example 1, Example 2, Example 3, Comparative Example 3 and Comparative Example 4, when (1000D+VF) / M<17, the compaction density of the active substance 12 is insufficient or the single-sided surface density of the active substance 12 is insufficient, the pole piece tension of the pole piece 1 to be die-cut is low or the moving speed of the pole piece 1 to be die-cut is low, which easily causes obvious wavy edges of the pole piece after die-cutting, resulting in incomplete cutting and die-cutting stripping; by adjusting the die-cutting parameters of the pole piece 1 to be die-cut so that it satisfies the relationship of 17≤(1000D+VF) / M≤20, the compaction density and single-sided surface density of the active substance 12 are sufficient, the pole piece tension of the pole piece 1 to be die-cut and the moving speed of the pole piece 1 to be die-cut are within a reasonable range, thereby reducing the wavy edges of the pole piece after die-cutting, avoiding the risk of die-cutting stripping, and improving the quality rate of the pole piece.

[0109] See also Figure 8 , is a schematic diagram of the structure of the battery provided in an embodiment of the present application.

[0110] This embodiment also provides a battery 4, which includes a positive electrode sheet 41, a negative electrode sheet 42 and a separator 43 arranged between the positive electrode sheet 41 and the negative electrode sheet 42; wherein at least one of the positive electrode sheet 41 and the negative electrode sheet 42 can be obtained by the electrode sheet die-cutting method described in any of the above embodiments.

[0111] Specifically, the positive electrode sheet 41, the negative electrode sheet 42 and the separator 43 can be used to construct a laminated battery cell or a wound battery cell. The battery 4 includes but is not limited to one of a soft-pack battery, a square battery or a cylindrical battery.

[0112] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0113] The above is a detailed introduction to the electrode die-cutting method, electrode and battery provided in this embodiment. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A die-cutting method for a pole piece, characterized in that: include: Providing a pole piece to be die-cut, wherein the surface of the pole piece to be die-cut has a coating area and a non-coating area located at least on one side of the coating area, and the pole piece to be die-cut includes an active material located in the coating area; The density characteristics of the active material are obtained, and based on the correlation relationship between the density characteristics of the active material and the die-cutting parameters of the electrode piece to be die-cut 17≤(1000D+VF) / M≤20, the die-cutting parameters of the electrode piece to be die-cut are determined, wherein D is the compaction density of the active material; V is the moving speed of the electrode piece to be die-cut during the die-cutting process; F is the electrode tension of the electrode piece to be die-cut during the die-cutting process; M is the single-sided surface density of the active material; The pole piece to be die-cut in the non-coating area is die-cut according to the die-cutting parameters of the pole piece to be die-cut.

2. The die-cutting method of the pole piece according to claim 1, characterized in that: The density characteristics of the active material include the compacted density of the active material and the single-surface density of the active material; The die-cutting parameters of the pole piece to be die-cut include the moving speed of the pole piece to be die-cut during the die-cutting process, and the pole piece tension of the pole piece to be die-cut during the die-cutting process.

3. The die-cutting method of the pole piece according to claim 2, characterized in that: The pole piece tension of the pole piece 1 to be die-cut during the die-cutting process is greater than or equal to 100N and less than or equal to 200N.

4. The die-cutting method of the pole piece according to claim 2, characterized in that: The single-sided surface density of the active material is greater than or equal to 200 g / m 2 , and less than or equal to 225g / m 2 .

5. The die-cutting method of the pole piece according to claim 2, characterized in that: The compacted density of the active material is greater than or equal to 2.58 g / cm 3 , and less than or equal to 2.62g / cm 3 .

6. The die-cutting method of the pole piece according to claim 2, characterized in that: The moving speed of the electrode to be die-cut during the die-cutting process is greater than or equal to 30 m / min and less than or equal to 60 m / min.

7. The die-cutting method of the pole piece according to claim 2, characterized in that: The thickness of the electrode piece to be die-cut is greater than or equal to 165 microns and less than or equal to 198 microns.

8. The die-cutting method of a pole piece according to any one of claims 1 to 7, characterized in that: The step of die-cutting the electrode piece to be die-cut in the non-coating area according to the die-cutting parameters of the electrode piece to be die-cut comprises: Using a laser die-cutting mechanism to die-cut the electrode piece to be die-cut in the non-coating area to form a pole ear; The die-cutting electrode piece to be die-cut is transferred to a stripping mechanism, and the stripping mechanism strips the electrode piece to be die-cut; The stripped pole piece is transferred to a winding mechanism, and the winding mechanism is used to wind up the pole piece.

9. A pole piece, characterized in that: The pole piece is obtained by the pole piece die-cutting method according to any one of claims 1 to 8.

10. A battery, characterized in that: The battery comprises the pole piece according to claim 9.

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