Electrode manufacturing equipment

Abstract

To reduce variation in depth of a groove part at continuous production.SOLUTION: A device of manufacturing an electrode includes a first roller, a second roller, a measuring apparatus, and a control device. The first roller is opposed to the second roller. The first roller is configured to carry an electrode to a roller gap between the first and second rollers. The second roller includes a projection part. The projection part is in contact with the electrode at the roller gap, and thereby, forms a groove part on a surface of the electrode. The measuring apparatus is configured to measure a depth of the groove part. The control device is configured to adjust the length of the roller gap when the measurement value of the depth is out of a reference range.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an electrode manufacturing apparatus. [Background technology]

[0002] Japanese Patent Laid-Open Publication No. 2015-138619 (Patent Document 1) discloses transferring a concave-convex pattern to a concave-convex structure formation preparatory layer by pressing a mold having the concave-convex pattern against the concave-convex structure formation preparatory layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-138619 Summary of the Invention [Problem to be solved by the invention]

[0004] It has been proposed to form grooves (concave portions) on the surface of an electrode. The grooves can serve as flow paths for the electrolyte, for example. The formation of grooves is expected to improve battery performance. For example, grooves can be formed by pressing a convex mold against the surface of the electrode. The shape of the grooves corresponds to the shape of the convex mold.

[0005] Electrodes can be continuously produced using the roll-to-roll method. During continuous production, the convex mold is used repeatedly. Continuous use of the convex mold may cause thermal expansion of the convex mold. Fluctuations in the dimensions of the convex mold may also cause fluctuations in the depth of the groove.

[0006] An object of the present disclosure is to reduce variations in groove depth during serial production. [Means for solving the problem]

[0007] The technical configuration and effects of the present disclosure will be described below. However, the mechanism of action in this specification includes speculation. The mechanism of action does not limit the technical scope of the present disclosure.

[0008] The electrode manufacturing apparatus includes a first roll, a second roll, a measuring device, and a control device. The first roll faces the second roll. The first roll is configured to transport the electrode through a roll gap between the first roll and the second roll. The second roll includes protrusions. The protrusions are configured to form grooves on the surface of the electrode by contacting the electrode in the roll gap. The measuring device is configured to measure the depth of the grooves. The control device is configured to adjust the size of the roll gap when the measured depth is outside a reference range.

[0009] The depth of the groove can be determined by the height of the protrusions (convex shapes) and the size of the roll gap. According to the new findings of the present disclosure, the protrusions can thermally expand during continuous production. In other words, the height of the protrusions is a variable that can change over time.

[0010] The electrode manufacturing equipment includes a feedback control system. The measuring device measures the depth of the groove. The control device adjusts the size of the roll gap when the measured depth is outside the reference range. In other words, the size of the roll gap can be corrected in response to changes in the height of the protrusions. Therefore, fluctuations in the depth of the groove can be reduced during continuous production.

[0011] Hereinafter, an embodiment of the present disclosure (hereinafter may be abbreviated as "the present embodiment") will be described. However, the present embodiment does not limit the technical scope of the present disclosure. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a conceptual diagram showing an example of an electrode manufacturing apparatus according to this embodiment. [Figure 2] FIG. 2 is a top view image showing an example of a groove portion. [Figure 3] FIG. 3 is a depth profile taken along line A-A' in FIG. [Figure 4] FIG. 4 is a conceptual diagram showing an example of a method for adjusting the roll gap. [Figure 5]FIG. 5 is a first graph showing an example of the time variation of depth. [Figure 6] FIG. 6 is a second graph showing an example of the time variation of the depth. [Figure 7] FIG. 7 is a schematic flowchart of a method for producing an electrode in this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] In this specification, the terms "comprise," "include," "have," and variations thereof (e.g., "consisting of") are open-ended. Open-ended terms may or may not include additional elements in addition to the required elements. The term "consisting of" is closed-ended. However, even in closed-ended terms, additional elements that are normally incidental impurities or unrelated to the disclosed technology are not excluded. The term "consisting essentially of..." is semi-closed. Semi-closed terms allow for the addition of elements that do not substantially affect the basic and novel characteristics of the disclosed technology.

[0014] In this specification, expressions such as "may" and "can" are used in the permissive sense of "possibly" rather than the obligatory sense of "must."

[0015] Geometric terms used in this specification (e.g., "parallel," "perpendicular," "orthogonal," etc.) should not be interpreted in a strict sense. For example, "parallel" may deviate slightly from the strict meaning of "parallel." Geometric terms used in this specification may include, for example, tolerances, errors, etc. in design, work, manufacturing, etc. The dimensional relationships in each drawing may not match the actual dimensional relationships. To facilitate understanding of the disclosed technology, the dimensional relationships (length, width, thickness, etc.) in each drawing may be changed. Furthermore, some configurations may be omitted.

[0016] In this specification, unless otherwise specified, a numerical range such as "m to n%" includes both the upper and lower limits. That is, "m to n%" indicates a numerical range of "m% or more and n% or less." Furthermore, "m% or more and n% or less" includes "more than m% and less than n%." Furthermore, a numerical value arbitrarily selected from within the numerical range may be set as a new upper or lower limit. For example, a new numerical range may be set by arbitrarily combining a numerical value within the numerical range with a numerical value described elsewhere in this specification, in a table, a figure, or the like.

[0017] In this specification, "electrode" is a general term for a positive electrode and a negative electrode. That is, an electrode may be a positive electrode or a negative electrode. In this specification, an electrode for a lithium ion battery is described as an example. However, the use of the electrode is arbitrary.

[0018] <Electrode manufacturing equipment> 1 is a conceptual diagram showing an example of an electrode manufacturing apparatus according to the present embodiment. Hereinafter, the "electrode manufacturing apparatus according to the present embodiment" may be abbreviated as "the manufacturing apparatus of the present embodiment." The manufacturing apparatus 100 includes a first roll 110, a second roll 120, a measuring device 130, and a control device 140. The manufacturing apparatus 100 may further include, for example, a coating device, a drying device, a compression device (none of which are shown), and the like.

[0019] <<First Roll>> The first roll 110 faces the second roll 120. The rotation axis of the first roll 110 is parallel to the rotation axis of the second roll 120. A roll gap 20 is formed between the first roll 110 and the second roll 120.

[0020] The first roll 110 may also be referred to as a "backup roll." The first roll 110 supports the electrode 10. The electrode 10 is transported by the rotation of the first roll 110. The first roll 110 transports the electrode 10 to the roll gap 20.

[0021] "electrode" The electrode 10 includes, for example, a substrate 1 and an active material layer 2. The active material layer 2 is disposed on the surface of the substrate 1. The substrate 1 may include, for example, a metal foil. The substrate 1 may include, for example, an aluminum foil or a copper foil. The substrate 1 may have a thickness of, for example, 5 to 50 μm. The active material layer 2 includes an active material. The active material may include, for example, lithium nickel cobalt manganese oxide, lithium iron phosphate, graphite, silicon, silicon oxide, etc. The active material layer 2 may further include, for example, a conductive material, a binder, etc. The active material layer 2 may have a thickness of, for example, 10 to 1000 μm, or 50 to 200 μm.

[0022] <<Second Roll>> The second roll 120 includes protrusions 121. The protrusions 121 are formed on the surface of the second roll 120. The second roll 120 may include a plurality of protrusions 121. The protrusions 121 may have various planar patterns. For example, the protrusions 121 may be linear, curved, or wavy. The protrusions 121 may be lattice-shaped or mesh-shaped.

[0023] The second roll 120 may also be referred to as a "concave-convex transfer roll." In the roll gap 20, the protrusions 121 come into contact with the electrode 10 (active material layer 2), thereby forming grooves 5 on the surface of the electrode 10 (active material layer 2). In other words, the concave-convex patterns are transferred to the surface of the electrode 10. The shape of the grooves 5 corresponds to the shape of the protrusions 121. In a cross section perpendicular to the rotation axis of the second roll 120, the protrusions 121 may be, for example, rectangular.

[0024] The depth of grooves 5 can be adjusted by the height of protrusions 121 and roll gap 20. Groove 5 may have a depth of, for example, 10 to 200 μm. The depth of groove 5 may be, for example, 1 to 90% of the thickness of active material layer 2.

[0025] <<Measuring Device>> The measuring device 130 measures the depth of the groove portion 5. The measuring device 130 can measure the depth of the groove portion 5 by any method. The measuring device 130 may include, for example, a laser displacement meter or the like. The measuring device 130 may include, for example, a laser displacement sensor "Model LJ-X8020" manufactured by Keyence Corporation.

[0026] FIG. 2 is a top view image showing an example of a groove. In FIG. 2, lattice-shaped grooves 5 are formed on the surface of the active material layer 2. For example, the depth of the grooves 5 is measured along line A-A'. FIG. 3 is a depth profile along line A-A' in FIG. 2. In FIG. 3, the grooves 5 have a depth of 51 μm. During continuous production, the protrusions 121 may thermally expand. When the protrusions 121 thermally expand, the depth of the grooves 5 may change. In other words, the grooves 5 may become deeper than the target value.

[0027] Control device The control device 140 performs feedback control of the roll gap 20. That is, the control device 140 adjusts the size of the roll gap 20 when the measured depth value is outside the reference range. The control device 140 acquires the measured depth value from the measuring device 130. The control device 140 compares the measured value with the reference range. For example, if the measured value is smaller than the lower limit of the reference range (if the groove 5 is shallow), the control device 140 may decrease the roll gap 20. For example, if the measured value is larger than the upper limit of the reference range (if the groove 5 is deep), the control device 140 may increase the roll gap 20. The reference range can be determined based on, for example, preliminary experiment results, dimensional tolerances, etc. The control device 140 can change the size of the roll gap 20 by any method.

[0028] FIG. 4 is a conceptual diagram showing an example of a method for adjusting the roll gap. The control device 140 may include, for example, a gap adjustment unit 145. The gap adjustment unit 145 supports the rotation shaft of the first roll 110. The gap adjustment unit 145 includes a first wedge portion 141 and a second wedge portion 142. For example, when the second wedge portion 142 shifts to the right on the paper, the first roll 110 moves slightly upward on the paper, and the roll gap 20 may become smaller. For example, when the second wedge portion 142 shifts to the left on the paper, the first roll 110 moves slightly downward on the paper, and the roll gap 20 may become larger. The second wedge portion 142 may be driven by, for example, a motor or the like.

[0029] First Modified Example The control device 140 may adjust the size of the roll gap 20 so that the difference between the measured depth and the reference value becomes smaller. The control device 140 acquires the measured depth value from the measuring device 130. The control device 140 determines the difference between the measured depth and the reference value. The size of the roll gap 20 may be corrected so that the difference becomes smaller. For example, the size of the roll gap 20 may be adjusted so that the difference becomes zero. For example, the roll gap 20 may be increased or decreased by an amount equal to the difference.

[0030] The measured depth value and the reference depth value may be, for example, moving average values. For example, a time average of the depth over a first period (first moving average value) is calculated. A time average of the depth over a second period following the first period (second moving average value) is calculated. The difference (amount of fluctuation) between the second moving average value and the first moving average value is calculated. Here, the first moving average value corresponds to the "reference depth value," and the second moving average value corresponds to the "measured depth value." The control device 140 may, for example, increase or decrease the size of the roll gap 20 by the amount of fluctuation.

[0031] FIG. 5 is a first graph showing an example of time-dependent fluctuations in depth. In FIG. 5, continuous production is carried out with a constant roll gap 20. A gradual increase in depth can be seen over time. The moving average of the depth increases by 2% overall. This is thought to be due to thermal expansion of the protrusions 121.

[0032] Fig. 6 is a second graph showing an example of time variation of depth. In Fig. 6, feedback control of the roll gap 20 is performed. Compared to Fig. 5, in Fig. 6, the variation of depth is reduced.

[0033] Second Modified Example Shape parameters other than the depth may be measured. Feedback control may be performed based on shape parameters other than the depth. Examples of shape parameters other than the depth include the width and taper angle of the groove portion 5.

[0034] <<Coating device>> The manufacturing apparatus 100 may further include a coating device (not shown). The coating device can form the active material layer 2 on the surface of the substrate 1. The coating device can form the active material layer 2 by any method. The coating device may include, for example, a roll coater, a die coater, or the like. The coating material may be, for example, a slurry or a wet powder.

[0035] 《Drying equipment》 The manufacturing apparatus 100 may further include a drying device (not shown). The drying device may dry the active material layer 2 after the grooves 5 are formed. The drying device may dry the active material layer 2 by any method. The drying device may include, for example, a hot air drying oven, an infrared heater, or the like.

[0036] Compression device The manufacturing apparatus 100 may further include a compression device (not shown). The compression device may compress the active material layer 2 after drying the active material layer 2. The compression device may compress the active material layer 2 by any method. The compression device may include, for example, a roll press or the like.

[0037] <Electrode manufacturing method> FIG. 7 is a schematic flowchart of a method for manufacturing an electrode according to this embodiment. Hereinafter, the "method for manufacturing an electrode according to this embodiment" may be abbreviated as "the present manufacturing method." This manufacturing method includes, for example, "(a) forming an active material layer," "(b) adjusting the roll gap," "(c) forming grooves," "(d) measuring the depth," and "(e) feedback control." This manufacturing method may further include "(f) drying."

[0038] That is, the present production method includes the following steps (a) to (e). (a) An active material layer 2 is formed on the surface of a substrate 1 to form an electrode 10. (b) The size of the roll gap 20 between the first roll 110 and the second roll 120 is adjusted. (c) In the roll gap 20, grooves 5 are formed on the surface of the active material layer 2. (d) The depth of the groove 5 is measured. (e) When the measured depth is outside the standard range, adjust the size of the roll gap 20. The first roll 110 faces the second roll 120. The first roll 110 transports the electrode 10 to the roll gap 20. The second roll 120 includes protrusions 121. In the roll gap 20, the protrusions 121 come into contact with the active material layer 2, thereby forming grooves 5 on the surface of the active material layer 2.

[0039] The present production method may further include the following (f) after the above (d). (f) The active material layer 2 is dried.

[0040] The present manufacturing apparatus may include the following (e') instead of the above (e). (e') The size of the roll gap 20 is adjusted so that the difference between the measured depth and the reference value becomes small.

[0041] The present embodiment is illustrative in all respects. The present embodiment is not restrictive. The technical scope of the present disclosure encompasses all modifications within the meaning and scope equivalent to the claims. For example, it is also intended from the beginning that any configuration may be extracted from the present embodiment and arbitrarily combined. [Explanation of symbols]

[0042] 1 substrate, 2 active material layer, 5 groove portion, 10 electrode, 20 roll gap, 100 manufacturing device, 110 first roll, 120 second roll, 121 protrusion portion, 130 measuring device, 140 control device, 141 first wedge portion, 142 second wedge portion, 145 gap adjustment portion.

Claims

[Claim 1] A first roll; A second roll; a measuring device; a control device; Including, The first roll faces the second roll, the first roll is configured to transport an electrode to a roll gap between the first roll and the second roll; the second roll includes a protrusion, the protrusions are configured to contact the electrode in the roll gap to form grooves on the surface of the electrode, the measuring device is configured to measure the depth of the groove; The control device is configured to adjust the size of the roll gap when the measured depth is outside a reference range. Electrode manufacturing equipment.

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