Method for manufacturing electrode sheets for non-aqueous secondary batteries

Abstract

This invention provides a method for manufacturing electrode sheets for non-aqueous secondary batteries, which allows for stable measurement results and adjustment of the compression amount of the electrode sheet based on the measurement results. [Solution] A method for manufacturing an electrode sheet for a non-aqueous secondary battery includes: a coating step of coating an electrode composite paste containing an active material onto the electrode substrate of the electrode sheet for the non-aqueous secondary battery; a pressing step of compressing the electrode sheet coated with the electrode composite paste onto the electrode substrate; a slitting step of cutting the pressed electrode sheet into multiple strips along its longitudinal direction; a winding step of winding the cut electrode sheets onto different roll cores for each strip; a measurement step of measuring the winding diameter of the electrode sheet wound onto the roll core; and a calculation step of calculating the theoretical winding diameter for the production length of the electrode sheet wound onto the roll core from a correlation formula. In the pressing step, the amount of compression of the electrode sheet is adjusted based on the winding diameter measured in the measurement step and the theoretical winding diameter calculated in the calculation step.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an electrode sheet for a non-aqueous secondary battery.

Background Art

[0002] In the electrode manufacturing apparatus described in Patent Document 1, the electrode in which the electrode mixture is coated on the current collector foil is pressed to be compressed, and the pressed electrode is wound around a roll core. In such an electrode manufacturing apparatus, after the electrode is pressed, the thickness of the electrode is measured.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the electrode manufacturing apparatus described in Patent Document 1, when measuring the electrode during conveyance after the electrode is pressed, there is a possibility that the variation in the measurement result may increase according to the conveyance speed.

Means for Solving the Problems

[0005] A method for manufacturing an electrode sheet for a non-aqueous secondary battery that solves the above problems includes: a coating step of coating an electrode composite paste containing an active material onto an electrode substrate of the electrode sheet for a non-aqueous secondary battery; a pressing step of compressing the electrode sheet coated with the electrode composite paste onto the electrode substrate; a slitting step of cutting the pressed electrode sheet into multiple strips along the longitudinal direction; a winding step of winding each strip onto a different roll core; a measurement step of measuring the winding diameter of the electrode sheet wound onto the roll core; and a calculation step of calculating the theoretical winding diameter for the production length of the electrode sheet wound onto the roll core from a correlation formula, wherein in the pressing step, the amount of compression of the electrode sheet is adjusted based on the winding diameter measured in the measurement step and the theoretical winding diameter calculated in the calculation step.

[0006] According to the above method, the winding diameter of the electrode sheet wound onto the roll core is measured, and the amount of compression of the electrode sheet in the pressing process is adjusted based on the measured winding diameter and the theoretical winding diameter calculated from the correlation formula. Therefore, since the winding diameter of the electrode sheet after it has been wound, rather than the electrode sheet in transit, is measured, stable measurement results can be obtained, and the amount of compression of the electrode sheet can be adjusted based on the measurement results.

[0007] Regarding the method for manufacturing the electrode sheet of the above-mentioned non-aqueous secondary battery, it is preferable that in the pressing step, the coated electrode sheet is compressed by a compression member extending in the width direction of the coated electrode sheet, in the measurement step, the winding diameter of each of the two cut electrode sheets located at both ends in the width direction of the electrode sheet before cutting is measured, and in the pressing step, the amount of compression of the electrode sheet is adjusted so that the winding diameters of the two cut electrode sheets located at both ends measured in the measurement step are the same.

[0008] Regarding the method for manufacturing the electrode sheet of the above-mentioned non-aqueous secondary battery, in the pressing step, it is preferable to adjust the amount of compression of the electrode sheet so that the difference between the measured winding diameter and the calculated theoretical winding diameter falls within a predetermined range.

[0009] Regarding the method for manufacturing the electrode sheet of the above-mentioned non-aqueous secondary battery, in the calculation step, it is preferable to calculate the theoretical winding diameter from the correlation formula using different correlation coefficients for each predetermined distance of the production length of the electrode sheet. [Effects of the Invention]

[0010] According to the present invention, stable measurement results can be obtained, and the amount of compression of the electrode sheet can be adjusted based on the measurement results. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view showing the schematic configuration of a cell of a non-aqueous secondary battery according to one embodiment. [Figure 2] This is a diagram showing a portion of the electrode body of the same embodiment unfolded. [Figure 3] Block diagram showing the method for manufacturing an electrode sheet according to the same embodiment. [Figure 4] This figure shows a winding device for the electrode sheet manufacturing method of the same embodiment. [Figure 5] This graph shows the winding diameter as a function of the production length of the electrode sheet in the same embodiment. [Figure 6] This is a block diagram showing a modified example of a method for manufacturing an electrode sheet. [Modes for carrying out the invention]

[0012] [This Circumstance] The following describes one embodiment of a method for manufacturing electrode sheets for a non-aqueous secondary battery, with reference to Figures 1 to 5. A lithium-ion secondary battery will be described as an example of a non-aqueous secondary battery.

[0013] [Lithium-ion rechargeable battery 10] As shown in Figure 1, the lithium-ion secondary battery 10 is a cell battery that, when combined with multiple other lithium-ion secondary batteries 10, is enclosed in a resin or metal case to form a battery pack. The battery pack is used in hybrid vehicles and electric vehicles.

[0014] The lithium-ion secondary battery 10 comprises a battery case 11 and a cover 12. The battery case 11 is rectangular in shape with an opening on its upper side. The cover 12 seals the opening of the battery case 11. The battery case 11 and the cover 12 are made of a metal such as aluminum or an aluminum alloy. The lithium-ion secondary battery 10 is formed as a sealed battery case by attaching the cover 12 to the battery case 11.

[0015] The cover 12 is provided with two positive external terminals 13A and a negative external terminal 13B. The positive external terminal 13A and the negative external terminal 13B are used for charging and discharging power. The electrode body 20 is housed inside the battery case 11. The positive electrode side current collector 20A, which is the positive electrode end of the electrode body 20, is electrically connected to the positive external terminal 13A via the positive electrode side current collector member 14A. The negative electrode side current collector 20B, which is the negative electrode end of the electrode body 20, is electrically connected to the negative external terminal 13B via the negative electrode side current collector member 14B. In addition, a non-aqueous electrolyte is injected into the battery case 11 through an injection hole (not shown). Note that the shapes of the positive external terminal 13A and the negative external terminal 13B are not limited to the shapes shown in Figure 1, but may be any shape.

[0016] [Electrode body 20] As shown in Figure 2, the electrode body 20 is a flat wound body formed by winding a laminate in which a long positive electrode sheet 21 and a negative electrode sheet 24 are laminated with a separator 27 in between. The positive electrode sheet 21, the negative electrode sheet 24, and the separator 27 are laminated so that their respective longitudinal directions coincide with the longitudinal direction D1. Before winding, the laminate is laminated in the order of positive electrode sheet 21, separator 27, negative electrode sheet 24, separator 27. The positive electrode sheet 21 and the negative electrode sheet 24 are electrode sheets.

[0017] [Positive electrode sheet 21] The positive electrode sheet 21 includes a positive electrode current collector 22 and a positive electrode composite material layer 23. The positive electrode current collector 22 is a foil-shaped positive electrode base material formed in a long shape. The positive electrode composite material layer 23 is provided on each of two opposing surfaces of the positive electrode current collector 22. The positive electrode current collector 22 includes a positive electrode side uncoated portion 22A at one end in the width direction D2 where the positive electrode current collector 22 is exposed without the formation of the positive electrode composite material layer 23.

[0018] The positive electrode current collector 22 is made of a metal foil composed of aluminum or an alloy mainly composed of aluminum. The positive electrode current collector 22 functions as a current collector in the positive electrode. The positive electrode side uncoated portion 22A included in the positive electrode current collector 22 forms a positive electrode side current collecting portion 20A with the opposing surfaces being pressed against each other in the state of the wound body.

[0019] The positive electrode composite material layer 23 is a cured body of a liquid positive electrode composite material paste. The positive electrode composite material paste includes a positive electrode active material, a positive electrode solvent, a positive electrode conductive material, and a positive electrode binder. The positive electrode composite material layer 23 is formed by drying the positive electrode composite material paste and vaporizing the positive electrode solvent. Therefore, the positive electrode composite material layer 23 includes a positive electrode active material, a positive electrode conductive material, and a positive electrode binder.

[0020] The positive electrode active material is a lithium-containing composite oxide capable of occluding and releasing lithium ions, which are charge carriers in the lithium-ion secondary battery 10. The lithium-containing composite oxide is an oxide containing lithium and other metal elements other than lithium. The other metal elements other than lithium are, for example, at least one selected from the group consisting of nickel, cobalt, manganese, vanadium, magnesium, molybdenum, niobium, titanium, tungsten, aluminum, and iron contained as iron phosphate in the lithium-containing composite oxide.

[0021] For example, lithium-containing composite oxides include lithium cobaltate (LiCoO2), lithium nickelate (LiNiO2), and lithium manganate (LiMn2O4). Another example is lithium-containing composite oxide, a ternary lithium-containing composite oxide containing nickel, cobalt, and manganese, which is lithium nickel-cobalt-manganate (LiNiCoMnO2). Yet another example is lithium iron phosphate (LiFePO4).

[0022] The positive electrode solvent is an NMP (N-methyl-2-pyrrolidone) solution, which is an example of an organic solvent. Examples of positive electrode conductive materials include carbon black such as acetylene black and Ketjenblack, carbon fibers such as carbon nanotubes and carbon nanofibers, and graphite. The positive electrode binder is an example of a resin component contained in the positive electrode composite paste. Examples of positive electrode binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), and styrene-butadiene rubber (SBR).

[0023] The positive electrode sheet 21 may have an insulating layer at the boundary between the uncoated portion 22A on the positive electrode side and the positive electrode composite layer 23. The insulating layer contains an inorganic component having insulating properties and a resin component that functions as a binder. The inorganic component is at least one selected from the group consisting of powdered boehmite, titania, and alumina. The resin component is at least one selected from the group consisting of PVDF, PVA, and acrylic.

[0024] [Negative electrode sheet 24] The negative electrode sheet 24 comprises a negative electrode current collector 25 and a negative electrode composite layer 26. The negative electrode current collector 25 is a foil-shaped negative electrode substrate formed in an elongated shape. The negative electrode composite layer 26 is provided on each of two opposing surfaces of the negative electrode current collector 25. The negative electrode current collector 25 has a negative electrode side unpainted portion 25A at one end in the width direction D2, which is located opposite the positive electrode side unpainted portion 22A, where the negative electrode composite layer 26 is not formed and the negative electrode current collector 25 is exposed.

[0025] The negative electrode current collector 25 is made of metal foil composed of copper or an alloy mainly composed of copper. The negative electrode current collector 25 functions as a current collector at the negative electrode. In the wound state, the unpainted negative electrode side portion 25A has opposing surfaces pressed against each other to form the negative electrode side current collector portion 20B.

[0026] The negative electrode composite layer 26 is a cured body of a liquid negative electrode composite paste. The negative electrode composite paste contains a negative electrode active material, a lithium salt, a negative electrode solvent, a negative electrode thickener, and a negative electrode binder. The negative electrode composite layer 26 is formed when the negative electrode composite paste is dried and the negative electrode solvent vaporizes. Therefore, the negative electrode composite layer 26 contains the negative electrode active material, a lithium salt, and further, as additives, a negative electrode thickener and a negative electrode binder. The negative electrode composite layer 26 may further contain additives such as a conductive material.

[0027] The negative electrode active material is a material capable of intercalating and releasing lithium ions. Examples of negative electrode active materials include carbon materials such as graphite, poorly graphitizable carbon, and easily graphitizable carbon. The negative electrode solvent is, for example, water. The lithium salt can be one or more lithium compounds (lithium salts) selected from LiPF6, LiBF4, LiClO4, LiAsF6, LiCF3SO3, LiC4F9SO3, LiN(CF3SO2)2, LiC(CF3SO2)3, LiI, and LiBOB (lithium bisoxalate borate). In this embodiment, LiBOB is used as the lithium salt. As an example of a negative electrode thickener, CMC (carboxymethylcellulose) can be used as a thickener containing a sodium salt. The negative electrode binder can be the same as the positive electrode binder. As an example of a negative electrode binder, SBR (styrene-butadiene copolymer) can be used as a binder containing a sodium salt.

[0028] [Separator 27] The separator 27 prevents contact between the positive electrode sheet 21 and the negative electrode sheet 24, and holds the non-aqueous electrolyte between the positive electrode sheet 21 and the negative electrode sheet 24. When the electrode body 20 is immersed in the non-aqueous electrolyte, the non-aqueous electrolyte penetrates from the ends in the width direction D2 of the separator 27 toward the center.

[0029] The separator 27 is a nonwoven fabric made of polypropylene or the like. As the separator 27, for example, porous polymer membranes such as porous polyethylene membranes, porous polyolefin membranes, and porous polyvinyl chloride membranes, and ion-conductive polymer electrolyte membranes can be used.

[0030] [Nonaqueous electrolyte] A non-aqueous electrolyte is a composition containing a supporting salt in a non-aqueous solvent. As the non-aqueous solvent, one or more materials selected from the group consisting of propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, etc., can be used. In this embodiment, ethylene carbonate is used as the non-aqueous solvent. As the supporting salt, one or more lithium compounds (lithium salts) selected from LiPF6, LiBF4, LiClO4, LiAsF6, LiCF3SO3, LiC4F9SO3, LiN(CF3SO2)2, LiC(CF3SO2)3, LiI, etc., can be used.

[0031] [Manufacturing method] Next, the manufacturing method of the lithium-ion secondary battery 10 will be described with reference to Figures 3 to 5. The manufacturing method of the lithium-ion secondary battery 10 involves winding up a laminate in which a positive electrode sheet 21 and a negative electrode sheet 24 are stacked with a separator 27 in between. The wound electrode body 20 is then placed in a battery case 11. Then, a non-aqueous electrolyte is injected into the battery case 11 containing the electrode body 20, and a lid 12 is attached to the battery case 11 to seal it.

[0032] As shown in Figure 3, the manufacturing method for the electrode sheet, which is part of the manufacturing method for the lithium-ion secondary battery 10, includes a coating step, a pressing step, a slitting step, a winding step, a measurement step, and a calculation step. In the pressing step, the amount of compression is adjusted based on the results of the measurement step. This manufacturing method is performed on at least one of the electrode sheets, the positive electrode sheet 21 and the negative electrode sheet 24.

[0033] [Coating Process] In the coating process, the coating apparatus 31 coats the electrode substrate, which has been unwound from the conveyor roller, with an electrode composite paste in which the active material is dispersed in a solvent. The electrode substrate of the positive electrode sheet 21 is coated with the positive electrode composite paste, which will become the positive electrode composite layer 23. The electrode substrate of the negative electrode sheet 24 is coated with the negative electrode composite paste, which will become the negative electrode composite layer 26. The coating apparatus 31 corresponds to the coating section.

[0034] [Pressing process] In the pressing process, the electrode sheet, which has been coated with electrode composite paste onto an electrode substrate, is compressed to a predetermined thickness by the pressing device 32. In the pressing process, the coated electrode sheet is compressed by a compression member, such as a press roll (not shown), which extends in the width direction of the coated electrode sheet. Therefore, if the compression member is tilted in the width direction, the thickness of one end of the electrode sheet in the width direction will increase, and the thickness of the other end will decrease. Therefore, in the pressing process, the amount of compression of the electrode sheet is adjusted based on the winding diameter measured in the measurement process described later. The pressing device 32 adjusts the amount of compression of the electrode sheet according to the instructions of the control device 30. The pressing device 32 corresponds to the pressing section.

[0035] The control device 30 comprises a calculation unit, a communication interface unit, a volatile memory unit, and a non-volatile memory unit. The calculation unit is a computer processor that controls the press device 32 according to a control program stored in the non-volatile memory unit (storage medium). The calculation unit may implement at least a portion of the processing it performs using a circuit such as an ASIC. The control program may be executed by a single computer processor or by multiple computer processors.

[0036] [Slitting process] In the slitting process, the pressed electrode sheet is cut into multiple strips along its longitudinal direction by the slitting device 33. In this embodiment, the electrode sheet is cut into two strips. The slitting device 33 corresponds to the slitting section.

[0037] [Winding process] In the winding process, the cut electrode sheets are wound onto different roll cores for each strip. Specifically, as shown in Figure 4, the single-strand winding device 34A winds the cut single-strand electrode sheet (positive electrode sheet 21 or negative electrode sheet 24) onto the first roll core 40A. Similarly, the double-strand winding device 34B winds the cut double-strand electrode sheet (positive electrode sheet 21 or negative electrode sheet 24) onto the second roll core 40B. The single-strand winding device 34A and the double-strand winding device 34B correspond to the winding sections.

[0038] [Measurement Process] In the measurement process, the winding diameter of the electrode sheet wound onto the roll core is measured. In the measurement process, the winding diameter of each of the two cut electrode sheets located at both ends in the width direction of the electrode sheet before cutting is measured. That is, as shown in Figure 4, the first winding diameter detection device 35A detects the winding diameter of the electrode sheet (positive electrode sheet 21 or negative electrode sheet 24) on the first roll core 40A. The first winding diameter detection device 35A is a non-contact thickness measuring device, for example, an ultrasonic sensor, which detects the winding diameter from the distance to the sensor. The first right detection device 41A and the first left detection device 41B each detect the winding diameter and output their average values ​​to the control device 30. Similarly, the second winding diameter detection device 35B detects the winding diameter of the electrode sheet (positive electrode sheet 21 or negative electrode sheet 24) on the second roll core 40B. The second winding diameter detection device 35B is a non-contact thickness measuring device, such as an ultrasonic sensor, which detects the winding diameter from the distance to the sensor. The second right detection device 42A and the second left detection device 42B each detect the winding diameter and output their average values ​​to the control device 30. The first winding diameter detection device 35A and the second winding diameter detection device 35B correspond to the measurement unit.

[0039] [Calculation process] In the calculation process, the theoretical winding diameter for the production length of the electrode sheet wound onto the roll core is calculated from a correlation formula. That is, as shown in Figure 5, the control device 30 determines the theoretical winding diameter Y [mm] for the production length X [m] from Y = AX + B. The correlation formula for calculating the theoretical winding diameter Y is prepared in advance for each specification of the electrode sheet. The intercept B is the value at the start of winding. The rate of increase of the theoretical winding diameter Y [mm] with respect to the production length X [m] gradually decreases. Therefore, as the theoretical winding diameter Y increases, the value of the slope A gradually decreases. Thus, in the calculation process, the theoretical winding diameter Y is calculated from the correlation formula using a slope A that corresponds to a different correlation coefficient for each predetermined distance of the production length X of the electrode sheet. Since changing the slope A as needed would increase the amount of calculation, the slope A is fixed for each predetermined distance of the production length X to calculate the theoretical winding diameter Y. For example, when the production length X is X1 or greater and less than X2, the theoretical winding diameter Y is calculated from Y = A1X + B1. If the production length X is between X2 and X3, the theoretical winding diameter Y is calculated from Y = A2X + B2. If the production length X is between X3 and X4, the theoretical winding diameter Y is calculated from Y = A3X + B3. The production length X may be calculated from the rotation speed of the roll core or from the rotation speed of the conveyor roller.

[0040] [Adjusting the amount of compression in the pressing process] In the pressing process, the amount of compression of the electrode sheet is adjusted so that the winding diameters of the two cut electrode sheets located at both ends in the width direction of the electrode sheet before cutting, as measured in the measurement process, are the same. That is, the control device 30 instructs the press device 32 so that the winding diameter of the first roll core 40A and the winding diameter of the second roll core 40B are the same. The press device 32 adjusts the amount of compression by correcting the inclination of the compression member in accordance with the instructions of the control device 30. In addition, in the pressing process, the amount of compression of the electrode sheet is adjusted so that the difference between the measured winding diameter and the theoretical winding diameter calculated from the correlation formula is within a predetermined range. That is, the control device 30 instructs the press device 32 so that the difference between the measured winding diameter and the theoretical winding diameter calculated from the correlation formula is within a predetermined range. The press device 32 adjusts the amount of compression by the compression member in accordance with the instructions of the control device 30.

[0041] [Effects of this embodiment] Next, the effects of this embodiment will be described. (1) The winding diameter of the electrode sheet wound onto the first roll core 40A and the second roll core 40B is measured, and the amount of compression of the electrode sheet in the pressing process is adjusted based on the measured winding diameter and the theoretical winding diameter calculated from the correlation formula. For this reason, the winding diameter of the electrode sheet after it has been wound, rather than the electrode sheet in transit, is measured, so stable measurement results can be obtained, and the amount of compression of the electrode sheet can be adjusted from the measurement results.

[0042] (2) The winding diameter of each of the two cut electrode sheets located at both ends in the width direction of the electrode sheet before cutting is measured. Therefore, even if three or more strips are cut, it is possible to determine from the two measurement points that the compression member is tilted during the pressing process and that the amount of compression differs on the left and right sides. Thus, the tilt of the compression member can be corrected.

[0043] (3) The amount of compression of the electrode sheet is adjusted so that the difference between the measured winding diameter and the calculated theoretical winding diameter is within a predetermined range. In this way, the electrode sheet can be manufactured to have the theoretical winding diameter calculated from the correlation formula.

[0044] (4) The theoretical winding diameter Y is calculated from the correlation formula using a different slope A for each predetermined distance of the production length X of the electrode sheet. Therefore, the amount of computation can be reduced compared to calculating the theoretical winding diameter Y by changing the slope A with respect to the production length X as needed.

[0045] [Other embodiments] The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0046] In the above embodiment, the first right detection device 41A and the first left detection device 41B each detected the winding diameter, and the average value was output to the control device 30. Similarly, the second right detection device 42A and the second left detection device 42B each detected the winding diameter, and the average value was output to the control device 30. However, the winding diameter of the electrode sheet wound onto a single roll core may be detected by a single detection device.

[0047] In the above embodiment, the pressed electrode sheet was cut into two strips. However, the pressed electrode sheet may be cut into three or more strips. For example, as shown in Figure 6, the pressed electrode sheet may be cut into four strips. In this case, four single-strip winding devices 34A, two-strip winding devices 34B, three-strip winding devices 34C, and four-strip winding devices 34D each wind up one of the four strips. The cut electrode sheets located at both ends in the width direction of the electrode sheet before cutting are wound up by the single-strip winding device 34A and the four-strip winding device 34D. The first winding diameter detection device 35A measures the winding diameter of the electrode sheet wound up by the single-strip winding device 34A, and the second winding diameter detection device 35B measures the winding diameter of the electrode sheet wound up by the four-strip winding device 34D. With this configuration, even if the number of winding devices increases, the first winding diameter detection device 35A and the second winding diameter detection device 35B measure only the electrode sheets wound on the winding devices at both ends, so the amount of compression of the press device 32 can be adjusted by measuring without increasing the number of winding diameter detection devices.

[0048] In the measurement process of the above embodiment, the theoretical winding diameter Y was calculated from the correlation formula with a different slope A for each predetermined distance of the production length X of the electrode sheet. However, the theoretical winding diameter Y may be calculated from the correlation formula at any time with a slope A corresponding to the production length X of the electrode sheet.

[0049] In the above embodiment, the amount of compression of the electrode sheet was adjusted so that the difference between the winding diameter measured in the pressing process and the calculated theoretical winding diameter was within a predetermined range. However, the amount of compression of the electrode sheet may also be adjusted so that the winding diameter measured in the pressing process and the calculated theoretical winding diameter are the same.

[0050] In the above embodiment, the winding diameters of the two cut electrode sheets located at both ends in the width direction of the electrode sheet before cutting were measured during the measurement process. However, multiple winding diameters may be measured in the measurement process, not limited to both ends of the cut electrode sheet, and the amount of compression of the electrode sheet may be adjusted in the pressing process so that the winding diameters of the two electrode sheets are the same.

[0051] In the above embodiment, the winding diameter of the electrode sheet wound onto a single roll core may be measured in the measurement process, and the amount of compression of the electrode sheet may be adjusted based on the winding diameter measured in the pressing process.

[0052] In the above embodiment, the theoretical winding diameter Y for the production length X of the electrode sheet wound onto the roll core was calculated from the correlation formula in the calculation process. However, the theoretical winding diameter Y for the production length X of the electrode sheet may be calculated in advance from the correlation formula and stored, and then read out.

[0053] The above embodiment includes a slitting step in which the pressed electrode sheet is cut into multiple strips along its longitudinal direction. However, the slitting step may be omitted. In the above embodiment, the control device 30 instructed the press device 32 to adjust the amount of compression by the compression member. However, the control device 30 and the press device 32 may be integrated, and the press device 32 may directly acquire the measured winding diameter and adjust the amount of compression.

[0054] The lithium-ion secondary battery 10 may be installed in automated transport machines, special vehicles for cargo handling, electric vehicles, hybrid vehicles, etc., as well as in computers and other electronic devices, or it may constitute a system other than those mentioned above. For example, it may be installed in mobile objects such as ships and aircraft, or it may be part of a power supply system that supplies electricity from a power plant to buildings and homes where the secondary battery is installed via a substation or the like. [Explanation of symbols]

[0055] 10…Lithium-ion rechargeable battery 11…Battery case 12... Lid 13A... Positive external terminal 13B…Negative external terminal 14A... Positive electrode current collector 14B... Negative electrode current collector 20...Electrode body 20A... Positive electrode current collector 20B... Negative electrode current collector 21…Positive electrode sheet 22...Positive electrode current collector 22A...Unpainted area on the positive electrode side 23…Positive electrode composite layer 24... Negative electrode sheet 25...Negative electrode current collector 25A...Unpainted area on the negative electrode side 26…Negative electrode composite material layer 27... Separator 30...Control device 31…Coating equipment 32… Pressing device 33... Slitting device 34A...Single-strand winding device 34B...Two-strap winding device 34C...3-strand winding device 34D...4-strap winding device 35A...First winding diameter detection device 35B...Second winding diameter detection device 40A...First roll core 40B... Second roll core 41A...First right detection device 41B...First left detection device 42A...Second right detection device 42B...Second left detection device

Claims

1. A coating process in which an electrode composite paste containing an active material is applied to the electrode substrate of the electrode sheet of a non-aqueous secondary battery, A pressing step in which the electrode sheet coated with the electrode composite paste is compressed on the electrode substrate, A slitting process in which the pressed electrode sheet is cut into multiple strips along the longitudinal direction, A winding process in which the cut electrode sheets are wound onto different roll cores for each strip, A measurement step for measuring the winding diameter of the electrode sheet wound onto the aforementioned roll core, The calculation step includes calculating the theoretical winding diameter for the production length of the electrode sheet wound onto the roll core from a correlation formula, In the pressing process, the amount of compression of the electrode sheet is adjusted based on the winding diameter measured in the measurement process and the theoretical winding diameter calculated in the calculation process. A method for manufacturing electrode sheets for non-aqueous secondary batteries.

2. In the pressing process, the coated electrode sheet is compressed by a compression member that extends in the width direction of the coated electrode sheet. In the measurement process described above, the winding diameter of each of the two cut electrode sheets located at both ends in the width direction of the electrode sheet before cutting is measured. In the pressing process, the amount of compression of the electrode sheet is adjusted so that the winding diameters of the two cut electrode sheets located at both ends, as measured in the measurement process, are the same. A method for manufacturing an electrode sheet for a non-aqueous secondary battery according to claim 1.

3. In the pressing process, the amount of compression of the electrode sheet is adjusted so that the difference between the measured winding diameter and the calculated theoretical winding diameter falls within a predetermined range. A method for manufacturing an electrode sheet for a non-aqueous secondary battery according to claim 1 or 2.

4. In the calculation step described above, the theoretical winding diameter is calculated from the correlation formula using different correlation coefficients for each predetermined distance of the production length of the electrode sheet. A method for manufacturing an electrode sheet for a non-aqueous secondary battery according to claim 3.

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