Method for setting rolling parameters in lithium battery pole piece rolling process

Abstract

The application discloses a method for setting rolling parameters in a lithium battery pole piece rolling process, which comprises the following steps: based on the process standard of the pole piece appearance and the wave edge height, rolling tests are carried out on the pole piece under different compaction densities to verify the relationship between the elongation of the material area and the elongation of the tab blank area and the tab dispensing area, and the ratio relationship between the elongation of the material area and the elongation of the tab blank area and the tab dispensing area under different compaction densities is determined; different elongation roller coating layer thicknesses and different stretching force values are set on the elongation roller to carry out elongation tests on the pole piece, the relationship between the elongation roller coating layer thickness and the stretching force value and the elongation of the pole piece blank is verified, and a fitting formula and an isogram of the elongation of the pole piece blank and the elongation roller coating layer thickness and the elongation stretching force value are obtained; based on the ratio relationship and the fitting formula, the stretching force value and the elongation roller coating layer thickness under the preset compaction density of the pole piece are calculated, and the isogram is verified.

Description

Technical Field

[0001] This invention relates to the field of battery electrode rolling technology, and in particular to a method for setting rolling parameters in the lithium battery electrode rolling process. Background Technology

[0002] With the energy density of lithium batteries soaring, the compaction density of positive electrode sheets has increased from 2.3 g / cm³ to over 2.65 g / cm³. Higher rolling line loads cause the elongation of the electrode sheet in the MD direction (longitudinal direction) to surge from 0.3% to over 1.5%. Specifically, the material zone elongates significantly due to the forced compression of the double-sided coating layer; the tab, with a thickness only equivalent to the base copper / aluminum foil and a roll gap greater than its thickness, is in a "suspended" state, its length remaining almost unchanged, creating a "length difference" between the material zone and the tab. When this difference approaches positive or negative infinity, exceeding the yield window of the electrode material, stress concentration triggers breakage; if the signs are opposite, edge wavy patterns form. A wave height > 1.5 mm results in a rejection (NG) result, a sharp drop in yield, and disruption of subsequent processes. Existing speed difference compensation technology can only be effective within ±0.3% elongation error by adjusting the speed difference of the stretching rollers. Once the batch fluctuation is too large, the defect rate will rebound to more than 5%, and it still relies on manual trial and error to adjust the machine, wasting more than 500m of electrode sheet each time.

[0003] Therefore, a technology is urgently needed to solve the above problems. Summary of the Invention

[0004] This invention addresses the issues of batch scrapping of lithium battery electrode rolling processes during the new product introduction stage due to repeated adjustments of tension parameters, and tape breakage induced by parameter mismatch during mass production. It provides a method for setting rolling parameters in the lithium battery electrode rolling process, which is an extremely precise method for controlling the tensile force value and the thickness of the extension roller coating layer, aiming to achieve a dual breakthrough of zero-scrap trial production and zero-tap-break production.

[0005] This invention is achieved through the following technical solution: A method for setting rolling parameters in a lithium battery electrode rolling process, comprising the following steps: S1. Based on the pre-set process standards for electrode appearance and wavy edge height, conduct rolling tests on the electrode under different compaction densities to verify the primary relationship between the elongation rate of the material area, the elongation rate of the blank area of ​​the electrode tab, and the elongation rate of the adhesive application area of ​​the electrode tab. S2. Based on the first relationship verification data, determine the ratio of the elongation of the tab blank area and the elongation of the tab dispensing area to the elongation of the material area under different compaction densities of the electrode sheet; S3. By setting different coating thicknesses and applying different tensile force values ​​on the stretching roller, an electrode stretching test was conducted to verify the second relationship between the coating thickness, tensile force value and the electrode blanking stretching rate. S4. Based on the verification data of the second relationship, the fitting formula of electrode blanking elongation rate with extension roller coating thickness and extension tensile force value is obtained by fitting, and the contour map of electrode tab blanking area elongation rate with extension roller coating thickness and tensile force value is drawn. S5. Based on the ratio relationship and fitting formula, calculate the required tensile force value and the thickness of the extension roller coating layer under the preset electrode compaction density, and verify them using the contour map.

[0006] Preferably, in step S1, the appearance standard of the electrode sheet is as follows: after the electrode sheet is rolled out of the main roller, the blank area of ​​the electrode tab and the glue application area of ​​the electrode tab are flat and without wrinkles; after the electrode sheet passes through the rear extension roller, the blank area of ​​the electrode tab is flat and slightly extended, and the glue application area of ​​the electrode tab is flat and without wrinkles.

[0007] Preferably, in step S1, the standard for the height of the wavy edge is ≤1.5mm.

[0008] Preferably, in step S1, the rolling test of the electrode sheet under different compaction densities to verify the first relationship between the elongation of the material area and the elongation of the tab blank area and the elongation of the tab glue application area includes: The electrode thickness under different compaction densities is calculated based on the formula relating electrode surface density and electrode compaction density. After rolling the electrode to the qualified electrode thickness using the electrode thickness as the standard, adjust the wavy edge height and electrode appearance of the electrode edge so that the wavy edge height and the electrode appearance of the electrode after exiting the main roller and the post-extension roller in the tab blank area and glue dispensing area meet the preset process standards. Before rolling, the dimensions of the tab blank area and the glue dispensing area are marked with different length directions. After the electrode sheet is rolled, the dimensional changes of the marked length after the electrode sheet exits the main roller and the rear extension roller are measured, and the dimensional elongation of the tab blank area and the glue dispensing area is calculated. Before rolling, dimensions in different length directions are marked on the surface of the material zone. After rolling the electrode, the dimensional change of the marked lengths in the material zone is measured, and the dimensional elongation of the material zone is calculated.

[0009] Preferably, in step S3, the step of setting different coating thicknesses on the stretching roller and applying different tensile force values ​​to conduct an electrode stretching test to verify the second relationship between the coating thickness, tensile force value, and electrode blanking elongation rate includes: Different thicknesses of stretching roll coating layers are set on the stretching roll, and different stretching tensile force values ​​are set; Different dimensions in the length direction are marked in the blank area and glue application area of ​​the electrode tab respectively. The electrode sheet is placed under the combined conditions of the thickness of the coating layer of the stretching roller and the tensile force value to conduct an electrode tab tensile and stretching test. Measure the dimensional change of the tab in the length direction before and after the tab is stretched, and calculate the elongation rate of the tab blank area in the length direction, i.e., the electrode blank elongation rate.

[0010] Preferably, in step S4, the fitting formula for the electrode blanking elongation rate, the thickness of the stretching roller coating layer, and the elongation tensile force value includes: Where ε is the elongation rate of the tab blank area, t is the thickness of the stretching roller coating layer, s is the stretching tensile force value, and R²=0.992.

[0011] Preferably, in step S5, calculating the required tensile force and the thickness of the stretching roller coating layer under the preset electrode compaction density based on the ratio relationship and the electrode blanking extension fitting formula includes: Based on the required electrode compaction density, the electrode is rolled to the corresponding standard thickness, and the elongation of the material zone is calculated. The required electrode blank elongation is calculated based on the ratio of the electrode blank elongation / electrode tab dispensing area elongation to the self-material area elongation. Substitute the desired electrode blanking target elongation rate into the electrode blanking elongation rate fitting formula to obtain the tensile force value corresponding to different elongation roller coating layer thicknesses.

[0012] Preferably, after verification using the contour map, if the verification results are consistent, a lower thickness of the stretching roller coating layer is selected first, and then the corresponding tensile force value is matched to obtain the tensile force value and the thickness of the stretching roller coating layer in the lithium battery electrode rolling process.

[0013] Preferably, in step S5, the required tensile force value and the thickness of the extension roller coating layer under the preset electrode compaction density are calculated as a combination of multiple sets of extension roller coating layer thicknesses and corresponding different tensile force values.

[0014] Preferably, the stretching roller coating layer comprises Teflon tape.

[0015] The method of this invention relies on the "standard rolling tensile force value and extension roller coating layer (such as Teflon tape) thickness setting system" to establish a quantitative evaluation of the tab morphology and the process specification of the wavy edge height. It deeply couples the ratio model of the material area elongation rate - the tab blank area - the tab glue application area elongation rate, and systematically compares the mapping relationship between the multi-element extension roller coating layer thickness and the tensile force spectrum on the tab tensile behavior. Using big data condensation, graphic fitting and formula analysis as tools, it extracts the standard value of the rolling tensile force value, which solves the problem of massive scrap of electrode sheets caused by repeated adjustments of the tensile force value and extension roller coating layer thickness in new product trial production. It also completely eradicates the stubborn problem of tape breakage in production with the optimal parameter solution, and achieves zero scrap and zero tape breakage in trial production.

[0016] The method of this invention standardizes the setting of parameters such as the rolling tensile force value and the thickness of the stretching roller coating layer for electrodes, especially positive electrodes, reducing the scrap rate of electrodes due to improper parameter adjustment and improving product qualification rate and production efficiency. Simultaneously, this method can intuitively evaluate the appearance quality of the electrode tabs, ensuring the matching between the elongation rate of the material area and the blanking area of ​​the electrode sheet and the elongation rate of the electrode tab dispensing area, providing a reliable basis for optimizing process parameters, and possessing good practicality and promotional value.

[0017] This invention deeply integrates DOE experimental design, data analysis, and multi-dimensional fitting algorithms. By setting the rolling tensile force value and the thickness of the extension roller coating layer, it effectively optimizes the problems of rolling strip breakage and electrode edge wavy edges. Through DOE experimental design, it verifies the ratio relationship between the material zone elongation and the required electrode blanking and electrode tab glue dispensing zone elongation under different compaction conditions, and determines the required amount of electrode blanking and electrode tab glue dispensing zone elongation under different compaction conditions.

[0018] In summary, the method of this invention completely abandons traditional trial-and-error or experience-based tension setting, replacing it with a "standard rolling tensile force value and extension roller coating thickness setting system." It uses the material zone-tab blank area and the difference in dispensing length as the sole core variables, and establishes quantitative indicators for tab morphology and upper limits for wavy edge processes using this "standard rolling tensile force value and extension roller coating thickness setting system." It locks the material zone elongation rate, tab blank area elongation rate, and tab dispensing area elongation rate to fixed proportions. Through systematic experiments on tensile force performance under different extension roller coating thicknesses, it uses big data fitting to derive standard tensile values ​​and Teflon thickness values. This eliminates the need for repeated adjustments in new product trials, reduces waste to zero, and completely eliminates tape breakage in mass production, achieving zero defects in both debugging and production. Attached Figure Description

[0019] Figure 1 This is a flowchart of the method for setting rolling parameters in the lithium battery electrode rolling process of the present invention.

[0020] Figure 2 This is a schematic diagram of the electrode sheet provided by the present invention.

[0021] Figure 3 This is a schematic diagram of the sampling electrode in determining the wave edge height of the present invention.

[0022] Figure 4 This is a schematic diagram showing the arrangement direction of the cutting lines on the sampling electrode sheet of the present invention.

[0023] Figure 5 This is a diagram obtained from the experiment of this invention.

[0024] Figure 6 This is a contour map obtained from the experiment of this invention. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0026] In this application, the electrode sheet includes a material area 1, electrode tab dispensing areas 2 arranged opposite each other on both sides of the material area, and an electrode tab blanking area 3, wherein the electrode tab blanking area 3 is located outside the electrode tab dispensing area 2. Figure 3 as well as Figure 4 The schematic diagram of the electrode shown is consistent with... Figure 2 The structures shown are the same. Figure 3 and Figure 4 The figure shown is Figure 2 The diagram shows the result obtained after rotating the needle clockwise or counterclockwise. The dark area in the middle is the material area, and the outermost area is the blank area for the electrode tab. The dark area and the outermost blank area for the electrode tab are the electrode tab dispensing area. Figure 4 The dotted lines along the material area are the cutting lines.

[0027] See Figure 1 As shown in the exemplary embodiment of this application, the method for setting rolling parameters in the lithium battery electrode rolling process includes the following steps: S1. Based on the pre-set process standards for electrode appearance and wavy edge height, conduct rolling tests on the electrode under different compaction densities to verify the primary relationship between the elongation rate of the material area, the elongation rate of the blank area of ​​the electrode tab, and the elongation rate of the adhesive application area of ​​the electrode tab. S2. Based on the first relationship verification data, determine the ratio of the elongation of the tab blank area and the elongation of the tab dispensing area to the elongation of the material area under different compaction densities of the electrode sheet; S3. By setting different coating thicknesses and applying different tensile force values ​​on the stretching roller, an electrode stretching test was conducted to verify the second relationship between the coating thickness, tensile force value and the electrode blanking stretching rate. S4. Based on the verification data of the second relationship, the fitting formula of electrode blanking elongation rate with extension roller coating thickness and extension tensile force value is obtained by fitting, and the contour map of electrode tab blanking area elongation rate with extension roller coating thickness and tensile force value is drawn. S5. Based on the ratio relationship and fitting formula, calculate the required tensile force value and the thickness of the extension roller coating layer under the preset electrode compaction density, and verify them using the contour map.

[0028] In this embodiment of the application, preferably, in step S1, the appearance standard of the electrode sheet is as follows: after the electrode sheet is rolled out of the main roller, the blank area of ​​the electrode tab and the adhesive area of ​​the electrode tab are flat and without wrinkles; after the electrode sheet passes through the rear extension roller, the blank area of ​​the electrode tab is flat and slightly extended, and the adhesive area of ​​the electrode tab is flat and without wrinkles.

[0029] In this embodiment of the application, preferably, the stretching roller coating layer includes Teflon tape, but it can also be other functional tapes, and is not limited thereto.

[0030] Preferably, in this embodiment of the application, in step S1, the standard for the wavy edge height is ≤1.5mm. The method for testing the wavy edge height is as follows: the electrode sampling length is ≥1m, such as... Figure 3 As shown, the electrode sheet must be wrinkle-free. The sampling process must maintain the original shape of the electrode sheet; damage to its original form is prohibited to avoid interfering with the measurement results. Mark the operating side and the driving side. Lay the sampled electrode sheet flat on the sampling table. Place a 1m long steel ruler horizontally and gently in the middle of the dispensing area of ​​the electrode sheet. Cut it through the middle of the dispensing area with a ceramic knife. Place the steel ruler in the middle of the material area and cut it through. Figure 4 As shown; transfer one of the electrodes to the marble countertop, use a steel ruler with a length of 10-20cm and an accuracy of 0.5mm to measure the highest distance from the edge of the side with the dotted adhesive area to the marble countertop, and record it. This gives the height of the wavy edge. Of course, other methods may also be used for measurement, but not limited to these.

[0031] In this embodiment of the application, the rolling test of the electrode sheet under different compaction densities is carried out, and the relationship between the elongation of the material area and the elongation of the blank area of ​​the electrode tab and the elongation of the adhesive application area of ​​the electrode tab is verified by DOE experiment.

[0032] In this embodiment of the application, preferably, in step S1, the rolling test of the electrode sheet under different compaction densities to verify the first relationship between the elongation of the material area and the elongation of the electrode tab blank area and the elongation of the electrode tab glue application area includes: The electrode thickness under different compaction densities is calculated based on the formula relating electrode surface density and electrode compaction density. After rolling the electrode to the qualified electrode thickness using the electrode thickness as the standard, adjust the wavy edge height and electrode appearance of the electrode edge so that the wavy edge height and the electrode appearance of the electrode after exiting the main roller and the post-extension roller in the tab blank area and glue dispensing area meet the preset process standards. Before rolling, the dimensions of the tab blank area and the glue dispensing area are marked with different length directions. After rolling the electrode sheet, the dimensional changes of the marked length after the electrode sheet exits the main roller and the rear extension roller are measured. The dimensional elongation rate of the tab blank area and the glue dispensing area are calculated, namely the elongation rate of the tab blank area and the elongation rate of the glue dispensing area. Before rolling, mark the dimensions in different length directions (such as 300mm, 400mm, 500mm) on the surface of the material area. After rolling the electrode, measure the dimensional change of the marked length of the material area and calculate the dimensional elongation of the material area, i.e., the material area elongation.

[0033] In this application, the relationship between the electrode surface density and the electrode compaction density is expressed by the formula: Electrode thickness = Surface density / Electrode compaction density + Foil thickness. Wherein, the dimensional elongation of the tab blank area and the adhesive application area = (Post-pressing dimension - Pre-pressing dimension) / Pre-pressing dimension * 100%.

[0034] Under different compaction densities of 2.3 g / cm³, 2.24 g / cm³, 2.55 g / cm³, and 2.65 g / cm³, the following summary data were obtained through the first relationship test or verification, as shown in Table 1. The ratio of the material area elongation to the (front elongation / back elongation) electrode blank / dispensing area elongation is shown in Table 1: Table 1

[0035] The final ratio of the material area elongation to the (front elongation / back elongation) electrode blank / dispensing area elongation is shown in Table 2 below: Table 2

[0036] In this embodiment of the application, different coating thicknesses and tensile force values ​​are applied to the stretching roller to conduct electrode stretching tests. The relationship between the coating thickness, tensile force value, and electrode blanking elongation rate is verified by DOE experiments.

[0037] In a preferred embodiment of this application, step S3, which involves setting different coating thicknesses on the stretching roller and applying different tensile force values ​​to perform an electrode stretching test and verifying the second relationship between the coating thickness, tensile force value, and electrode blanking elongation rate, includes: Different thicknesses of stretching roller coating layers are set on the stretching roller to achieve different differential speed effects, and different stretching tensile force values ​​are set. Different dimensions in the length direction are marked in the blank area and glue application area of ​​the electrode tab respectively. The electrode sheet is placed under the combined conditions of the thickness of the coating layer of the stretching roller and the tensile force value to conduct an electrode tab tensile and stretching test. Measure the dimensional change of the tab in the length direction before and after stretching, and calculate the elongation rate of the tab blank area in the length direction. The dimensional elongation rate is calculated as follows: (Dimension after pressing - Dimension before pressing) / Dimension before pressing * 100%), which is the electrode blank elongation rate.

[0038] It should be noted that in this application, during the second relationship verification, when selecting an electrode, such as a positive electrode, the parameters of the electrode, including foil thickness, foil tensile strength, foil elongation, tab width, adhesive thickness, and adhesive width, are statistically analyzed to ensure that the parameters of the selected electrode match those of the electrode used in the first relationship verification. Specifically, the parameters or specifications of the selected electrode, such as foil thickness, foil tensile strength, foil elongation, tab width, adhesive thickness, and adhesive width, are consistent or within the error range, ensuring that the basic material conditions for the two relationship tests are consistent. For example, an electrode with a foil thickness of 12+2μm, foil tensile strength of 230MPa, foil elongation of 3.5%, tab width of 18mm, adhesive thickness of 80μm, and adhesive width of 8mm is selected for the electrode tensile test.

[0039] If we select different thicknesses of the stretching roller coating (700μm, 840μm, 980μm, 1120μm) and different tensile force values ​​(300N, 400N, 500N, 600N), after verification of the second relationship, we can obtain the data shown in Table 3 below. Table 3

[0040] In this embodiment of the application, in step S4, different Teflon tape thicknesses and different tensile strength values ​​are fitted with the tab whitening elongation rate to analyze the main factors affecting the tab whitening elongation rate, such as... Figure 5 As shown, process contour maps can be generated using Mintab data analysis software, such as... Figure 6 As shown.

[0041] In this embodiment of the application, the fitting formula for the electrode blanking elongation rate, the thickness of the stretching roller coating layer, and the stretching tensile force value in step S4 includes: Where ε is the elongation rate of the tab blank area, t is the thickness of the stretching roller coating layer, s is the stretching tensile force value, R²=0.992, and R² approaching 1 indicates that the measurement data is accurate.

[0042] In this embodiment, after obtaining the ratio relationship and the fitting formula, given the known relationship between the elongation rate of the material area and the elongation rate requirements of the tab blank area and the glue application area, as well as the tensile force value required for tab elongation, the standard value of the tensile force value for the rolling process can be obtained by combining the two through data lookup and formula calculation. In one embodiment, step S5, calculating the required tensile force and the thickness of the stretching roller coating layer under the preset electrode compaction density based on the ratio relationship and the electrode blanking extension fitting formula, includes: Based on the required electrode compaction density, the electrode is rolled to the corresponding standard thickness, and the dimensional elongation test in the length direction of the material area is carried out to calculate the elongation rate of the material area. The required electrode blank elongation is calculated based on the ratio of the electrode blank elongation / electrode tab dispensing area elongation to the self-material area elongation. Substitute the desired electrode blanking target elongation rate into the electrode blanking elongation rate fitting formula to obtain the tensile force value corresponding to different elongation roller coating layer thicknesses.

[0043] In this application, as mentioned above, the electrode blanking area elongation rate is divided into the pre-extension electrode blanking area elongation rate and the post-extension electrode blanking area elongation rate, and the dispensing area elongation rate is divided into the pre-extension dispensing area elongation rate and the post-extension dispensing area elongation rate. Specifically, during the electrode rolling process, the electrode blanking / dispensing area elongation rates of the pre-extension / post-extension processes are processed according to the pre-extension / post-extension electrode blanking / dispensing area elongation rates, and the required tensile force value and the thickness of the extension roller coating layer under the corresponding preset electrode compaction density under the pre-extension / post-extension processes are calculated.

[0044] In this embodiment, step S5 calculates the required tensile force and the thickness of the stretching roller coating layer under the preset electrode compaction density as a combination of multiple sets of stretching roller coating layer thicknesses and corresponding different tensile force values. Assuming the required electrode blank elongation rate is 0.7%, the required tensile force and Teflon tape thickness are as shown in Figure 4: Table 4

[0045] After calculating the elongation rate, based on the required elongation rate, in Figure 6 Find the corresponding area and verify the accuracy of the calculated values.

[0046] In this embodiment of the application, preferably, after verification using the contour map, if the inspection results are consistent, a lower thickness of the stretching roller coating layer is selected first, and then the corresponding tensile force value is matched to obtain the tensile force value and the thickness of the stretching roller coating layer in the lithium battery electrode rolling process. Specifically, since the thickness of the Teflon tape is affected by the thickness of a single layer of tape and cannot be precisely controlled, the thickness of the Teflon tape is selected first, and then a lower Teflon tape thickness is preferably selected based on the appearance of the electrode tab, and then the stretching tensile force value is selected. After determining the tensile force value and the thickness of the extension roller coating layer in the lithium battery electrode rolling process according to the method of the present invention, and selecting the target parameter value, the obtained tensile force value and extension roller coating layer thickness result value are used to perform positive electrode rolling adjustment. The appearance and wavy edge of the rolled electrode meet the process standards.

[0047] This invention establishes appearance process standards for the blank area and glue application area of ​​the electrode sheet. It requires that after the electrode sheet is rolled out by the main roller, the blank area of ​​the electrode ear and the glue application area are flat and wrinkle-free; after passing through the extension roller, the blank area of ​​the electrode ear is flat and slightly extended; and the glue application area is flat and wrinkle-free. The standard is used to judge whether the trial-produced electrode sheet meets the process requirements and achieves standard unification. It also establishes a process standard that the height of the wavy edge of the electrode sheet is ≤1.5mm.

[0048] In summary, the standard tensile force setting method and standard Teflon tape thickness setting method of the present invention provide a technically reasonable standard tensile force value and standard Teflon tape thickness for the rolling mill, which meet the rolling process requirements, solve the problem of a large number of electrode scraps caused by frequent adjustment of tension parameters, and optimize the rolling tape breakage problem by making the parameter settings more reasonable.

[0049] As can be seen from the above, this invention, through a closed-loop process of "process standard setting → product information statistics → DOE verification of the relationship between compaction density and electrode blank area and dispensing area → differential speed / tensile force value DOE test → data fitting," determines the required Teflon tape thickness and tensile force value. Through DOE experimental design, it quantifies the fixed ratio between the electrode material area elongation and the electrode tab blank area and dispensing area elongation, determining the required elongation of the electrode blank area and dispensing area under different compaction densities. Through DOE experimental design, it verifies the electrode tab elongation under different Teflon tape thicknesses and tensile force values, deriving the primary and secondary factors affecting the electrode tab, contour maps, and establishing a contour map fitting formula for Teflon tape thickness, tensile force value, and electrode tab elongation. This allows for the determination of the required tensile force value for different elongation rates, enabling rapid reproduction of the optimal differential speed and tension combination under different compaction densities and foil specifications, reducing electrode scrap rate and improving battery consistency.

[0050] Compared with the existing method of setting rolling parameters based solely on experience, this standard setting method achieves the following: it sets clear targets for ≤1.5mm wavy edge height and zero wrinkles on the tabs / application, unifying process judgment; it shortens the machine setup time by ≥50% by replacing trial and error with mathematical models; and it can quickly reproduce the optimal combination of differential speed and tension under different compaction densities and foil specifications, reducing electrode scrap rate and improving battery consistency, which is of great significance.

[0051] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of the equivalents of the claims be included within the invention.

[0052] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for setting rolling parameters in the lithium battery electrode rolling process, characterized in that, Including the following steps: S1. Based on the pre-set process standards for electrode appearance and wavy edge height, conduct rolling tests on the electrode under different compaction densities to verify the primary relationship between the elongation rate of the material area, the elongation rate of the blank area of ​​the electrode tab, and the elongation rate of the adhesive application area of ​​the electrode tab. S2. Based on the first relationship verification data, determine the ratio of the elongation of the tab blank area and the elongation of the tab dispensing area to the elongation of the material area under different compaction densities of the electrode sheet; S3. By setting different coating thicknesses and applying different tensile force values ​​on the stretching roller, an electrode stretching test was conducted to verify the second relationship between the coating thickness, tensile force value and the electrode blanking stretching rate. S4. Based on the verification data of the second relationship, fit the fitting formula of electrode blanking elongation rate with extension roller coating thickness and extension tensile force value, and draw the contour map of electrode tab blanking area elongation rate with extension roller coating thickness and tensile force value. S5. Based on the ratio relationship and fitting formula, calculate the required tensile force value and the thickness of the extension roller coating layer under the preset electrode compaction density, and verify them using the contour map.

2. The method for setting rolling parameters in the lithium battery electrode rolling process according to claim 1, characterized in that, In step S1, the appearance standard of the electrode sheet is as follows: after the electrode sheet is rolled out of the main roller, the blank area of ​​the electrode tab and the glue application area of ​​the electrode tab are flat and without wrinkles; after the electrode sheet passes through the rear extension roller, the blank area of ​​the electrode tab is flat and slightly extended, and the glue application area of ​​the electrode tab is flat and without wrinkles.

3. The method for setting rolling parameters in the lithium battery electrode rolling process according to claim 1, characterized in that, In step S1, the standard for the height of the wavy edge is ≤1.5mm.

4. The method for setting rolling parameters in the lithium battery electrode rolling process according to claim 1, characterized in that, In step S1, the rolling test of the electrode sheet under different compaction densities to verify the first relationship between the elongation of the material area and the elongation of the tab blank area and the elongation of the tab glue application area includes: The electrode thickness under different compaction densities is calculated based on the formula relating electrode surface density and electrode compaction density. After rolling the electrode to the qualified electrode thickness using the electrode thickness as the standard, adjust the wavy edge height and electrode appearance of the electrode edge so that the wavy edge height and the electrode appearance of the electrode after exiting the main roller and the post-extension roller in the tab blank area and glue dispensing area meet the preset process standards. Before rolling, the dimensions of the tab blank area and the glue dispensing area are marked with different length directions. After the electrode sheet is rolled, the dimensional changes of the marked length after the electrode sheet exits the main roller and the rear extension roller are measured, and the dimensional elongation of the tab blank area and the glue dispensing area is calculated. Before rolling, dimensions in different length directions are marked on the surface of the material zone. After rolling the electrode, the dimensional change of the marked lengths in the material zone is measured, and the dimensional elongation of the material zone is calculated.

5. The method for setting rolling parameters in the lithium battery electrode rolling process according to claim 1, characterized in that, In step S3, the step of setting different coating thicknesses and applying different tensile force values ​​on the stretching roller to conduct an electrode stretching test, and verifying the second relationship between the coating thickness, tensile force value, and electrode blanking elongation rate, includes: Different thicknesses of stretching roll coating layers are set on the stretching roll, and different stretching tensile force values ​​are set; Different dimensions in the length direction are marked in the blank area and glue application area of ​​the electrode tab respectively. The electrode sheet is placed under the combined conditions of the thickness of the coating layer of the stretching roller and the tensile force value to conduct an electrode tab tensile and stretching test. Measure the dimensional change of the tab in the length direction before and after the tab is stretched, and calculate the elongation rate of the tab blank area in the length direction, i.e., the electrode blank elongation rate.

6. The method for setting rolling parameters in the lithium battery electrode rolling process according to claim 1, characterized in that, In step S4, the fitting formula for the electrode blanking elongation rate, the thickness of the stretching roller coating layer, and the stretching tensile force value includes: Where ε is the elongation rate of the tab blank area, t is the thickness of the stretching roller coating layer, s is the stretching tensile force value, and R²=0.

992.

7. The method for setting rolling parameters in the lithium battery electrode rolling process according to claim 1, characterized in that, In step S5, the step of calculating the required tensile force and the thickness of the stretching roller coating layer under the preset electrode compaction density based on the ratio relationship and the electrode blanking extension fitting formula includes: Based on the required electrode compaction density, the electrode is rolled to the corresponding standard thickness, and the elongation of the material zone is calculated. The required electrode blank elongation is calculated based on the ratio of the electrode blank elongation / electrode tab dispensing area elongation to the self-material area elongation. Substitute the desired electrode blanking target elongation rate into the electrode blanking elongation rate fitting formula to obtain the tensile force value corresponding to different elongation roller coating layer thicknesses.

8. The method for setting rolling parameters in the lithium battery electrode rolling process according to claim 1, characterized in that, After verification using the contour map, if the test results are consistent, a lower thickness of the stretching roller coating layer is selected first, and then the corresponding tensile force value is matched to obtain the tensile force value and the thickness of the stretching roller coating layer in the lithium battery electrode rolling process.

9. The method for setting rolling parameters in the lithium battery electrode rolling process according to claim 8, characterized in that, In step S5, the calculated tensile force value and the thickness of the extension roller coating layer under the preset electrode compaction density are multiple sets of combined data of extension roller coating layer thickness and corresponding different tensile force values.

10. The method for setting rolling parameters in the lithium battery electrode rolling process according to claim 1, characterized in that, The coating layer of the stretching roller includes Teflon tape.

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