Apparatus for manufacturing electrode

Abstract

An apparatus for manufacturing an electrode, according to one embodiment of the present invention, comprises: a plurality of calendering rolls arranged at predetermined intervals such that electrode sheets are sequentially rolled; a plurality of rotary shafts extending from both ends of each of the plurality of calendering rolls; and a housing including openings through which the rotary shafts pass, wherein each of the rotary shafts includes a distal portion positioned on the opening and supported by the housing and a proximal portion positioned between the calendering roll and the distal portion, and the diameter of the proximal portion connected to at least one calendering roll among the plurality of calendering rolls can be different from the diameters of the proximal portions connected to the remaining calendering rolls.

Description

Electrode manufacturing device

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0107408, filed August 12, 2024, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to an electrode manufacturing device, and more particularly, to an electrode manufacturing device capable of alleviating deformation occurring in a calendaring roll and a rotating shaft connected to the calendaring roll by high pressure.

[0004] In modern society, the widespread use of portable devices like cell phones, laptops, camcorders, and digital cameras, as well as energy storage systems (ESS), has led to active development of related technologies. Furthermore, rechargeable secondary batteries are increasingly being used as power sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (P-HEVs) to address air pollution issues caused by conventional gasoline-powered vehicles. This, in turn, heightens the need for further development of these batteries.

[0005] Currently commercialized secondary batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium secondary batteries. Among these, lithium secondary batteries are receiving the most attention due to their advantages of free charging and discharging, low self-discharge rate, and high energy density.

[0006] The manufacturing process for these lithium secondary batteries is broadly divided into three stages: electrode processing, assembly processing, and formation processing. The electrode processing is further subdivided into active material mixing, electrode coating, rolling, slitting, and winding processes. Among these, the electrode coating process is divided into a wet process, which applies an active material slurry to the electrode current collector, and a dry process, which applies the active material to the current collector in a solid state.

[0007] When forming electrodes using a wet process, the solvent evaporates and is removed, potentially creating defects such as pinholes or cracks in the electrode active material layer. Furthermore, the drying process consumes significant energy to remove the large volume of solvent, and requires large, expensive drying equipment, significantly reducing the overall processability of the secondary battery.

[0008] To overcome the shortcomings of these wet processes, research has been actively conducted recently on methods for manufacturing dry electrodes for secondary batteries through a dry process that does not use solvents.

[0009] The dry electrode process is a method of manufacturing an electrode by mixing electrode active materials, binders, and conductive materials without a liquid medium such as a solvent or dispersion medium, manufacturing the powder mixture into a dry electrode sheet through a calendaring process, and laminating the manufactured dry electrode sheet onto a current collector.

[0010] This dry electrode process has the advantages of excellent electrode adhesion and life characteristics due to uniform binder distribution in the direction of electrode thickness, low interfacial reaction resistance on the surface of the active material because the binder does not directly cover the surface of the active material, favorable movement of lithium ions within the electrode, and very high electrode flexibility due to the use of a fiberizable binder.

[0011] Figure 1 is a schematic drawing of a conventional electrode manufacturing device.

[0012] Referring to FIG. 1, a conventional electrode manufacturing device (10) may include a plurality of calendaring rolls (1, 2, 3, 4). The plurality of calendaring rolls (1, 2, 3, 4) are arranged in multiple stages adjacent to each other, and a stretching process may be performed as the electrode sheet (6) runs between each of the calendaring rolls (1, 2, 3, 4) arranged in multiple stages.

[0013] That is, as the electrode sheet (6) passes between the plurality of multi-stage calendering rolls (1, 2, 3, 4), the thickness of the electrode sheet (6) can be sequentially reduced. Accordingly, since the gap between the plurality of calendering rolls (1, 2, 3, 4) may be different depending on the thickness of the electrode sheet (6), the external force applied to each of the plurality of calendering rolls (1, 2, 3, 4) may be different from each other. In general, since the gap between the plurality of calendering rolls (1, 2, 3, 4) is very small compared to the thickness of the electrode sheet (6) being input, a considerable external force may be applied to each component of the electrode manufacturing device (10), and in severe cases, this may cause equipment failure or deterioration in the quality of the electrode. However, there was no adjustment in the design of each part, particularly the rotating shaft connected to the calendering rolls (1, 2, 3, 4), according to the size of the external force applied to each of the plurality of calendaring rolls (1, 2, 3, 4), and thus there was a problem in that severe deformation occurred in the plurality of calendaring rolls (1, 2, 3, 4) and the rotating shaft connected thereto.

[0014] The problem to be solved by the present invention is to provide an electrode manufacturing device capable of alleviating deformation occurring in a calendaring roll and a rotating shaft connected to the calendaring roll due to high linear pressure.

[0015] However, the problems to be solved by the embodiments of the present invention are not limited to the problems described above and can be expanded in various ways within the scope of the technical ideas included in the present invention.

[0016] An electrode manufacturing device according to one embodiment of the present invention comprises a plurality of calendering rolls arranged at predetermined intervals so that an electrode sheet is sequentially rolled, a plurality of rotational axes extending from both ends of each of the plurality of calendering rolls, and a housing including an opening through which the rotational axes pass, wherein each of the rotational axes includes a distal portion positioned on the opening and supported by the housing, and a proximal portion positioned between the calendering roll and the distal portion, and a diameter of the proximal portion connected to at least one of the plurality of calendering rolls may be different from a diameter of the proximal portion connected to the remaining calendering rolls.

[0017] The diameter of the proximal portion connected to at least one of the plurality of calendaring rolls can be determined based on the magnitude of the linear pressure exerted by the at least one calendaring roll.

[0018] The diameter of the proximal portion connected to the calendering roll located at the uppermost end in the direction of travel of the electrode sheet among the plurality of calendering rolls may be larger than the diameter of the proximal portion connected to the remaining calendering rolls.

[0019] The diameter of the proximal portion connected to the second-positioned calendering roll based on the direction of travel of the electrode sheet among the plurality of calendering rolls may be larger than the diameter of the proximal portion connected to the remaining calendering rolls except for the calendering roll located at the top.

[0020] The diameter of the proximal portion connected to the calendering roll located at the lowermost end in the direction of travel of the electrode sheet among the plurality of calendering rolls may be smaller than the diameter of the proximal portion connected to the remaining calendering rolls.

[0021] When the linear pressure of one of the plurality of calendaring rolls is greater than the linear pressure of another calendaring roll, the diameter of the proximal portion connected to one of the calendaring rolls may be greater than the diameter of the proximal portion connected to the other of the calendaring rolls.

[0022] The magnitude of the linear pressure exerted by the above-mentioned plurality of calendaring rolls can be reduced toward the downstream of the above-mentioned direction of movement.

[0023] The square of the diameter of the above proximal portion can have a linear relationship with the magnitude of the above pressure.

[0024] The diameters of each of the distal portions connected to the plurality of calendaring rolls may be the same.

[0025] The housing may further include a bearing portion formed on the opening to support the distal portion.

[0026] The housing may include a plurality of housings that individually support the rotational axis.

[0027] The above electrode manufacturing device may further include a connecting member disposed between two adjacent housings among the plurality of housings.

[0028] The electrode manufacturing device according to embodiments of the present invention can improve the phenomenon of increasing the gap between neighboring calendaring rolls by alleviating the deformation occurring in the calendaring roll and the rotating shaft connected to the calendaring roll due to high pre-pressure, and at the same time, can improve the deformation (i.e., distortion) occurring in the housing supporting the plurality of calendaring rolls.

[0029] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0030] Figure 1 is a schematic drawing of a conventional electrode manufacturing device.

[0031] FIG. 2 is a perspective view showing a battery manufacturing device according to one embodiment of the present invention.

[0032] Fig. 3 is a side view showing the side of the battery manufacturing device of Fig. 2.

[0033] Figure 4 is a schematic diagram showing a calendaring roll of the battery manufacturing device of Figure 2 and a rotating shaft connected to the calendaring roll.

[0034] FIG. 5 is a schematic diagram for explaining the diameter of the proximal portion of the rotational axis connected to each calendaring roll of the battery manufacturing device according to one embodiment of the present invention.

[0035] Figure 6 is a schematic diagram showing the force applied to the calendaring roll and the rotating shaft connected to the calendaring roll of the battery manufacturing device of Figure 2.

[0036] FIG. 7 is a partially enlarged view illustrating strain relief of a first calendaring roll and a first rotational axis of a battery manufacturing device according to one embodiment of the present invention.

[0037] FIG. 8 is a partially enlarged view illustrating deformation relief of a first housing of a battery manufacturing device according to one embodiment of the present invention.

[0038] FIG. 9 is a partially enlarged view illustrating stress relaxation acting at the proximal portion of the first rotation axis of a battery manufacturing device according to one embodiment of the present invention.

[0039] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0040] In order to clearly explain the present invention, parts that are not related to the description are omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0041] Furthermore, the sizes and thicknesses of each component shown in the drawings are arbitrarily indicated for convenience of explanation, and thus the present invention is not necessarily limited to the illustrated components. In the drawings, the thicknesses are enlarged to clearly represent various layers and regions. Furthermore, in the drawings, the thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0042] Furthermore, when we say that a layer, membrane, region, plate, or other part is "on" or "over" another part, this includes not only cases where it is "directly on" the other part, but also cases where there are other parts in between. Conversely, when we say that a part is "directly on" another part, it means that there are no other parts in between. Furthermore, saying that a part is "on" or "over" a reference part means that it is located above or below the reference part, and does not necessarily mean that it is located "above" or "over" the direction opposite to gravity.

[0043] Additionally, terms indicating directions such as front, back, left, right, up, and down are used, but these terms are only for convenience of explanation and may vary depending on the location of the target object or the location of the observer.

[0044] Additionally, throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0045] Additionally, throughout the specification, when we say "in plan", we mean when the target portion is viewed from above, and when we say "in cross section", we mean when the target portion is viewed from the side in a cross-section cut vertically.

[0046] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0047] Fig. 2 is a perspective view showing a battery manufacturing device according to one embodiment of the present invention. Fig. 3 is a side view showing a side of the battery manufacturing device of Fig. 2.

[0048] Referring to FIGS. 2 and 3, a battery manufacturing device (100) according to one embodiment of the present invention may include a plurality of calendaring rolls (110) arranged at predetermined intervals so that electrode sheets are sequentially rolled, a plurality of rotational axes (120) extending from both ends of each of the plurality of calendaring rolls (110), and a housing (130) including an opening through which each of the rotational axes (120) of the plurality of calendaring rolls (110) passes.

[0049] A plurality of calendaring rolls (110) are generally cylindrical members. The plurality of calendaring rolls (110) are rotatable about a rotation axis (120). A dry electrode sheet (not shown) may be stretched as it travels between the plurality of calendaring rolls (110). The thickness of the electrode sheet may be determined by the spacing between adjacent calendaring rolls, etc. That is, the narrower the spacing between the calendaring rolls, the thinner the electrode sheet may be.

[0050] Meanwhile, in the examples illustrated in FIGS. 1 and 2, the number of the plurality of calendaring rolls (111, 112, 113, 114) and their accompanying components is illustrated as four, and will be referred to as a first calendaring roll (111), a second calendaring roll (112), a third calendaring roll (113), and a fourth calendaring roll (114) from upstream to downstream based on the direction of travel of the electrode sheet. Similarly, the components accompanying the plurality of calendaring rolls (111, 112, 113, 114) will also be referred to by adding ordinal numbers based on the direction from upstream to downstream based on the direction of travel of the electrode sheet. The following description will also be based on this, but the number of the plurality of calendaring rolls and their accompanying components may be variously modified or changed depending on the environment in which the present invention is implemented.

[0051] In addition, for the convenience of explanation, the plurality of calendaring rolls and their accompanying components are distinguished by ordinal numbers such as first, second, third, and fourth from upstream to downstream in the direction of travel of the electrode sheet, but this is used for the purpose of distinguishing one of the plurality of components from the rest, and is not used to limit the components by such terms.

[0052] The rotation shaft (120) may be formed by protruding from each of the ends of the plurality of calendaring rolls (110). Meanwhile, a driving means (not shown) for rotating each of the rotation shafts (121, 122, 123, 124) may be connected. Power is transmitted from the driving means to each of the rotation shafts (121, 122, 123, 124), so that the calendaring rolls (111, 112, 113, 114) connected to the rotation shafts (121, 122, 123, 124) can rotate. At this time, each of the calendaring rolls (111, 112, 113, 114) can be rotated independently of each other. Meanwhile, a specific description of the rotation shaft (120) will be described later.

[0053] The housing (130) can support each of a plurality of calendaring rolls (110). For this purpose, an opening through which a rotation shaft (120) passes may be formed in the housing (130). The housing (130) may be formed integrally to support each of a plurality of calendaring rolls (110), and may be formed of a plurality of housings (131, 132, 133, 134) as illustrated in FIGS. 2 and 3 . Meanwhile, for the convenience of explanation, the following description will be based on the assumption that the housing (130) is a plurality of housings (131, 132, 133, 134).

[0054] The plurality of housings (130) may be formed to individually support each of the rotation shafts (120). That is, a pair of housings (130) may each support a rotation shaft (120) extending from both ends of a calendaring roll (110). For example, a pair of first housings (131) each support a first rotation shaft (121) extending from both ends of a first calendaring roll (111). In the embodiment of the present invention, the plurality of housings (130) have a roughly rectangular shape, but the shapes of the plurality of housings (130) may be variously modified or changed depending on the environment in which the present invention is implemented. Meanwhile, the following description will be made based on the case where the plurality of housings (130) have a rectangular shape.

[0055] A battery manufacturing device (100) according to one embodiment of the present invention may further include a plurality of bearing parts (140) formed on an opening of a housing (130) to support a rotation shaft (120) and a plurality of connecting members (150) arranged between two adjacent housings among the plurality of housings (130) to respectively contact the two adjacent housings.

[0056] The bearing part (140) is arranged in the opening of the plurality of housings (130) through which each of the rotation shafts (120) passes, and can support the weight of each of the rotation shafts (120) and the external force applied to the rotation shafts (120). At this time, the external force applied to the rotation shafts (120) may be a force generated due to the linear pressure of the calendering rolls (110) when the dry electrode sheet is stretched as it runs between the plurality of calendaring rolls (110), but the type of the external force applied to the rotation shafts (120) is not limited by the above-described. That is, the above-described external force refers to various types of forces applied to the rotation shafts (120) while the battery manufacturing device (100) is in operation. The friction between the rotation shafts (120) and the housings (130) is reduced by the bearing part (140), so that the plurality of calendaring rolls (110) can rotate smoothly. At this time, the type of bearing part (140) can be modified or changed in various ways depending on the environment in which the present invention is implemented.

[0057] The connecting member (150) is arranged between two adjacent housings among the plurality of housings (130) and comes into contact with the two adjacent housings (130), respectively. Accordingly, the connecting member (150) can adjust the gap between the two adjacent calendaring rolls (110). In addition, since the connecting member (150) is arranged between the two adjacent housings (130), it can transmit force from one housing (130) to the adjacent housing (130). Meanwhile, a groove (not shown) for accommodating the connecting member (151, 152, 153) may be formed in the plurality of housings (131, 132, 133, 134). Since the connecting member (150) transmits force to the adjacent housings (130) and maintains the gap between the plurality of calendaring rolls (110), it can be formed of a metal having excellent tensile strength, ductility, and wear resistance. For example, the connecting member (150) may be formed of a metal having a high elastic modulus, and as an example of a metal having a high elastic modulus, may be formed of carbon steel, mainly S45C.

[0058] FIG. 4 is a schematic diagram showing a calendaring roll of the battery manufacturing device of FIG. 2 and a rotary shaft connected to the calendaring roll. FIG. 5 is a schematic diagram for explaining the diameter of the proximal portion of the rotary shaft connected to the calendaring roll of the battery manufacturing device according to one embodiment of the present invention. FIG. 6 is a schematic diagram showing a force applied to the calendaring roll of the battery manufacturing device of FIG. 2 and a rotary shaft connected to the calendaring roll.

[0059] Referring to FIGS. 4 to 6, the rotation shaft (120) may include a distal portion (127) positioned on the opening of the housing (130) and supported by the housing (130), and a proximal portion (126) positioned between the calendering roll (110) and the distal portion (127). The proximal portion (126) is a portion extending parallel to the longitudinal direction of the calendering roll (110) from both ends of the calendering roll (110). In addition, the distal portion (127) may be formed to extend parallel to the longitudinal direction of the calendering roll (110) from the distal end of the proximal portion (126).

[0060] At this time, the diameter of the proximal portion (126) connected to at least one of the plurality of calendaring rolls (111, 112, 113, 114) may be different from the diameter of the proximal portion (126) connected to the remaining calendaring rolls (111, 112, 113, 114).

[0061] Specifically, the diameter of the proximal portion (126) connected to at least one of the plurality of calendaring rolls (111, 112, 113, 114) can be determined based on the magnitude of the linear pressure by the calendaring rolls (111, 112, 113, 114). In general, the plurality of calendaring rolls (111, 112, 113, 114) can roll the electrode sheet to produce it in a thin form, and the linear pressure means a value obtained by dividing the pressure (or force) applied to the electrode sheet by the plurality of calendaring rolls (111, 112, 113, 114) by the contact length (width) of the calendaring rolls (111, 112, 113, 114).

[0062] The external force applied to each of the rotation axes (121, 122, 123, 124) of the plurality of calendaring rolls (111, 112, 113, 114) is affected by the linear pressure applied to the electrode sheet by each calendaring roll (111, 112, 113, 114). Accordingly, the diameter of the proximal portion (126) of the rotation shaft (121, 122, 123, 124) is determined according to the external force (i.e., the linear pressure of the calendaring roll) applied to each of the rotation shafts (121, 122, 123, 124) of the plurality of calendaring rolls (111, 112, 113, 114), so that the deformation occurring in the calendaring rolls (111, 112, 113, 114) and the rotation shafts (121, 122, 123, 124) connected to each of the calendaring rolls (111, 112, 113, 114) due to the high linear pressure can be alleviated. Through this, the electrode manufacturing device (100) according to one embodiment of the present invention can improve the phenomenon in which the gap between neighboring calendaring rolls (111, 112, 113, 114) increases due to deformation occurring in the calendaring rolls (111, 112, 113, 114) and the rotating shafts (121, 122, 123, 124) connected to the calendaring rolls (111, 112, 113, 114), and at the same time, can improve deformation (i.e., distortion) occurring in the housing (131, 132, 133, 134) supporting the plurality of calendaring rolls (111, 112, 113, 114).

[0063] First, the diameter (D1) of the proximal portion (1261) connected to the calendering roll (111) located at the uppermost end in the direction of travel of the electrode sheet among the plurality of calendering rolls (111, 112, 113, 114) may be larger than the diameters (D2, D3, D4) of the proximal portions (1262, 1263, 1264) connected to the remaining calendering rolls (112, 113, 114). In general, the linear pressure by the calendering roll (111) located at the uppermost end in the direction of travel of the electrode sheet among the plurality of calendering rolls (111, 112, 113, 114) may be larger than the linear pressure by the remaining calendering rolls (112, 113, 114). Accordingly, since the diameter (D1) of the proximal portion (1261) connected to the calendering roll (111) located at the uppermost end in the direction of travel of the electrode sheet among the plurality of calendering rolls (111, 112, 113, 114) is determined to be the largest, the amount of deformation occurring in the first rotation axis (121) of the first calendering roll (111) on which the largest linear pressure is applied among the plurality of calendering rolls (111, 112, 113, 114) can be reduced.

[0064] The diameter (D2) of the proximal portion (1262) connected to the second-positioned calendering roll (112) based on the running direction of the electrode sheet among the plurality of calendering rolls (111, 112, 113, 114) may be larger than the diameters (D3, D4) of the proximal portions (1263, 1264) connected to the remaining calendering rolls (113, 114) except for the uppermost-positioned calendering roll (111). In general, the linear pressure by the second-positioned calendering roll (112) based on the running direction of the electrode sheet among the plurality of calendering rolls (111, 112, 113, 114) may be larger than the linear pressure by the remaining calendering rolls (113, 114) except for the uppermost-positioned calendering roll (111). Accordingly, by making the diameter (D2) of the proximal part (1262) connected to the second-positioned calendering roll (112) based on the traveling direction of the electrode sheet among the plurality of calendering rolls (111, 112, 113, 114) larger than that of the proximal parts (1263, 1264) connected to the remaining calendering rolls (113, 114) except for the calendering roll (111) located at the top, it is possible to reduce the amount of deformation occurring in the second rotation shaft (122) connected to the second calendering roll (112) to which a greater linear pressure is applied than that of the remaining calendering rolls (113, 114) except for the calendering roll (111) located at the top among the plurality of calendering rolls (111, 112, 113, 114).

[0065] The diameter of the proximal portion (1264) connected to the calendering roll (114) located at the lowest end in the direction of travel of the electrode sheet among the plurality of calendering rolls (111, 112, 113, 114) may be smaller than the diameter of the proximal portions (1261, 1262, 1263) connected to the remaining calendering rolls (111, 112, 113). In general, the remaining calendering rolls (111, 112, 113), excluding the calendering roll (114) located at the lowest end in the direction of travel of the electrode sheet among the plurality of calendering rolls (111, 112, 113, 114), are used for the purpose of increasing the energy density of the electrode sheet, and therefore a relatively large linear pressure may be applied. On the other hand, since the calendering roll (114) located at the lowest end in the direction of running of the electrode sheet among the plurality of calendering rolls (111, 112, 113, 114) is used for the purpose of laminating the electrode sheet onto the current collector, a relatively small linear pressure can be applied to the calendering roll (114) located at the lowest end compared to the remaining calendering rolls (111, 112, 113). Accordingly, the diameter (D4) of the proximal portion (1264) connected to the calendering roll (114) located at the lowest end in the direction of running of the electrode sheet among the plurality of calendering rolls (111, 112, 113, 114) can be made smaller than the diameters (D1, D2, D3) of the proximal portions (1261, 1262, 1263) connected to the remaining calendering rolls (111, 112, 113).

[0066] In summary, in the electrode manufacturing device (100) according to one embodiment of the present invention, when the linear pressure by one of the plurality of calendaring rolls (111, 112, 113, 114) is greater than the linear pressure by another calendaring roll (111, 112, 113, 114), the diameter of the proximal part (1261, 1262, 1263, 1264) connected to one of the plurality of calendaring rolls (111, 112, 113, 114) is greater than the diameter of the proximal part (1261, 1262, 1263, 1264) connected to the other calendaring roll (111, 112, 113, 114). It can be larger than the diameter.

[0067] For example, the magnitude of the linear pressure by the plurality of calendaring rolls (111, 112, 113, 114) may decrease toward the downstream in the direction of movement. That is, the magnitude of the linear pressure by the first calendaring roll (111) may be greater than the magnitude of the linear pressure by the second calendaring roll (112). Similarly, the magnitude of the linear pressure by the second calendaring roll (112) may be greater than the magnitude of the linear pressure by the third calendaring roll (113), and the magnitude of the linear pressure by the third calendaring roll (113) may be greater than the magnitude of the linear pressure by the fourth calendaring roll (114). Accordingly, the diameter (D1) of the proximal portion (1261) connected to the first calendaring roll (111) may be greater than the diameter (D2) of the proximal portion (1262) connected to the second calendaring roll (112). In addition, the diameter (D2) of the proximal portion (1262) connected to the second calendaring roll (112) may be larger than the diameter (D3) of the proximal portion (1263) connected to the third calendaring roll (113). Finally, the diameter (D3) of the proximal portion (1263) connected to the third calendaring roll (113) may be larger than the diameter (D4) of the proximal portion (1264) connected to the fourth calendaring roll (114). However, the relationship between the magnitudes of the linear pressures by the plurality of calendaring rolls (111, 112, 113, 114) is not limited to the above-described, and may be variously modified or changed depending on the environment in which the present invention is implemented.

[0068] More specifically, referring to (a) of Fig. 6, the calendaring roll (110) is subjected to a linear pressure ( ) is acting, and an external force ( ) is applied from the housing (130) to the bearing part (140) in the distal part (127). ) is in effect. Here, the line pressure ( ) is the force applied to the calendaring roll (110) by the electrode sheet per unit length of the calendaring roll (110), and the external force ( ) is the force applied to the distal portion (127) from the housing (130) through the bearing portion (140) per unit length of the distal portion (127). is the width of the electrode sheet, and D is the diameter of the proximal portion (126).

[0069] If the linear pressure applied to the calendaring roll (110) ) is a distributed load, shear stress rather than bending stress may be applied primarily to the proximal portion (126) of the rotation axis (120). In general, the rotation axis (120) may be in the shape of a cylinder, and the maximum shear stress in the shape of a cylinder ( ) is as shown in the following mathematical formula 1. Here, the maximum shear stress ( ) refers to the yield strength of a material, that is, the stress that causes permanent deformation of the material.

[0070] [Mathematical Formula 1]

[0071]

[0072] Here, is the maximum shear stress, P is the shear load, and A is the cross-sectional area.

[0073] Referring to (b) of Fig. 6, the shear load (P) and the line pressure ( ) is as shown in the following mathematical formula 2.

[0074] [Equation 2]

[0075]

[0076] Referring to the above mathematical expressions 1 and 2, the diameter (D) and the line pressure ( ) can be derived from the following mathematical equation 3.

[0077] [Equation 3]

[0078]

[0079] At this time, the maximum shear stress ( ) can be determined depending on the type of material of the rotation axis (120), and the width of the electrode sheet ( ) may be constant. However, as described above, the types of force acting on the proximal portion (126) may include, in addition to the force due to shear deformation, the force due to bending deformation, the friction due to contact with other parts, the force due to the oil path for temperature increase, etc. Accordingly, the diameter (D) of the proximal portion (126) may be determined as in the following mathematical expression 4.

[0080] [Equation 4]

[0081]

[0082] Here, a is the maximum shear stress of the rotation axis (120). ), the width of the electrode sheet ( ) can be determined by the other force factors mentioned above.

[0083] According to the above mathematical expression 4, the square of the diameter of the proximal part (126) is the linear pressure ( ) and has a linear relationship. By determining the diameter of the proximal portion (126) based on the above mathematical expression 4, the stress acting on the proximal portion (126) can be distributed, and the deformation of the calendaring roll (110) and the rotation shaft (120) can be alleviated. However, a detailed description thereof will be described later with reference to FIGS. 7 to 9.

[0084] Meanwhile, the diameters of the respective distal portions (1271, 1272, 1273, 1274) connected to the plurality of calendaring rolls (111, 112, 113, 114) may be the same. As in the example illustrated in FIG. 5, bearing portions (141, 142, 143, 144) arranged on the openings of the plurality of housings (131, 132, 133, 134) may be coupled to the respective distal portions (1271, 1272, 1273, 1274) connected to the plurality of calendaring rolls (111, 112, 113, 114) to support the respective distal portions (1271, 1272, 1273, 1274).

[0085] If all parts of the rotary shaft (120) connected to the plurality of calendaring rolls (110) are formed with the same diameter, the diameters of the respective rotary shafts (121, 122, 123, 124) may be formed differently depending on the linear pressure applied by each calendaring roll (111, 112, 113, 114). In this case, the size of the bearing portion (141, 142, 143, 144) may vary depending on the diameter of each rotary shaft (121, 122, 123, 124), and further, the size of the opening of the housing (131, 132, 133, 134) in which the bearing portion (141, 142, 143, 144) is installed may also vary. That is, a design and manufacturing problem may arise in that the opening size of the housing (131, 132, 133, 134) must be formed differently for each calendaring roll (111, 112, 113, 114). In addition, when the electrode sheet manufactured through the electrode manufacturing device (100) is changed, a problem may arise in that the entire housing (131, 132, 133, 134) must be replaced depending on the line pressure of each calendaring roll (111, 112, 113, 114).

[0086] Therefore, in order to solve the above-described problem, the rotation shaft (120) according to one embodiment of the present invention may include a distal portion (127) which is a portion positioned on the opening of the housing (130) and a proximal portion (126) positioned between the calendering roll (110) and the distal portion (127). At this time, the diameters of the respective distal portions (1271, 1272, 1273, 1274) connected to the plurality of calendering rolls (111, 112, 113, 114) may be the same, and the diameters (D1, D2, D3, D4) of the respective proximal portions (1261, 1262, 1263, 1264) may be determined according to the magnitude of the linear pressure by each of the respective calendering rolls (111, 112, 113, 114). Accordingly, the size of the opening of the housing (131, 132, 133, 134) and the bearing portion (141, 142, 143, 144) can be formed identically regardless of each calendaring roll (111, 112, 113, 114).

[0087] FIG. 7 is a partially enlarged view illustrating strain relief of a first calendaring roll and a first rotational axis of a battery manufacturing device according to one embodiment of the present invention. FIG. 8 is a partially enlarged view illustrating strain relief of a first housing of a battery manufacturing device according to one embodiment of the present invention. FIG. 9 is a partially enlarged view illustrating stress relief acting at a proximal portion of a first rotational axis of a battery manufacturing device according to one embodiment of the present invention.

[0088] In FIGS. 7 to 9, (a) shows the simulation results of deformation and / or stress occurring in the first calendaring roll (111'), the first rotational axis (121'), the first housing (131'), and the proximal portion (1261') of the first rotational axis (121') when the diameter of the proximal portion (1261', 1262', 1263', 1264') of each rotational axis (121', 122', 123', 124,) is formed to be the same regardless of the linear pressure by each calendaring roll (111', 112', 113', 114'). In addition, (b) in FIGS. 7 to 9 shows simulation results of deformation and / or stress occurring in the first calendaring roll (111), the first rotational axis (121), the first housing (131), and the proximal portion (1261) of the first rotational axis (121) when the diameter of the proximal portion (1261, 1262, 1263, 1264) of each rotational axis (121, 122, 123, 124) is determined according to the linear pressure by each calendaring roll (111, 112, 113, 114) according to one embodiment of the present invention.

[0089] As illustrated in (a) of Fig. 7, when the diameter of the proximal portion (1261') of the first calendering roll (111') on which the greatest linear pressure is applied among the plurality of calendering rolls (111', 112', 113', 114') is formed to be the same as that of the other calendering rolls (112', 113', 114'), the deformation of the first calendering roll (111') and the first rotational shaft (121') connected thereto occurs more than in the case illustrated in (b) of Fig. 7. Accordingly, as the electrode sheet runs between the first calendering roll (111') and the second calendering roll (112'), the degree of the gap between the first calendering roll (111') and the second calendering roll (112') decreases in the case of (b) of Fig. 7 compared to the case of (a) of Fig. 7.

[0090] For example, in the case of (a) of FIG. 7, the simulation result derived that the gap between the first calendaring roll (111') and the second calendaring roll (112') is 294 um at the center and 194 um at the end. On the other hand, in the case of (b) of FIG. 7, the simulation result derived that the gap between the first calendaring roll (111) and the second calendaring roll (112) is 248 um at the center and 148 um at the end. Therefore, it can be seen that in the case of the electrode manufacturing device (100) according to one embodiment of the present invention, the degree of gap between the first calendaring roll (111) and the second calendaring roll (112) is improved. In addition, the simulation results show that the maximum stress applied to the first calendaring roll (111) and the first rotation shaft (121) connected thereto is lower in the case of Fig. 7 (b) than in the case of Fig. 7 (a), and the simulation results show that the stress is distributed more overall in the case of Fig. 7 (b) than in the case of Fig. 7 (a).

[0091] The simulation results showed that the degree of deformation of the first housing (131') shown in (a) of Fig. 8 was alleviated compared to the degree of deformation of the first housing (131) shown in (b) of Fig. 8. The reason for this simulation result is that, as described above in Fig. 7, when the diameter of the proximal part (1261') connected to the first calendaring roll (111') inserted into the first housing (131') is formed to be the same as that of the proximal parts (1262', 1263', 1264') connected to the other calendaring rolls (112', 113', 114'), the deformation in the first calendaring roll (111') and the first rotation shaft (121') connected thereto occurs more than in the case shown in (b) of Fig. 7. That is, since the deformation occurring in the first rotation axis (121') affects the first housing (131') into which the first rotation axis (121') is inserted, the degree of deformation occurring in the first housing (131') illustrated in (a) of FIG. 8 may be greater than the degree of deformation occurring in the first housing (131) illustrated in (b) of FIG. 8.

[0092] As shown in (a) of Fig. 9, when the diameter of the first proximal portion (1261') of the first calendaring roll (111') on which the greatest linear pressure is applied among the plurality of calendaring rolls (111', 112', 113', 114') is formed to be the same as that of the other calendaring rolls (112', 113', 114'), the simulation results show that a relatively large stress is applied to the area adjacent to the first calendaring roll (111') of the first proximal portion (1261'). On the other hand, as shown in (b) of FIG. 7, when the diameter of the first proximal portion (1261) of the first calendaring roll (111) on which the greatest linear pressure is applied among the plurality of calendaring rolls (111, 112, 113, 114) is formed to be larger than that of the other calendaring rolls (112, 113, 114), the simulation results show that the magnitude of the stress applied to the area adjacent to the first calendaring roll (111) in the first proximal portion (1261) is reduced compared to the case of (a) of FIG. 9.

[0093] For example, when comparing the magnitude of the maximum stress acting on the first proximal portion (1261') illustrated in (a) of FIG. 9 with the magnitude of the maximum stress acting on the proximal portion (1261) illustrated in (b) of FIG. 9, it can be seen that the maximum stress is reduced by about 30 MPa in the case illustrated in (b) of FIG. 9. Accordingly, in the case of the electrode manufacturing apparatus (100) according to one embodiment of the present invention, it can be seen that the magnitude of the maximum stress acting on the first proximal portion (1261) connected to the first calendering roll (111) is reduced. Accordingly, the electrode manufacturing apparatus (100) according to one embodiment of the present invention can improve the durability of the plurality of calendering rolls (111, 112, 113, 114) and each component accompanying them, and thus, the lifespan of each component can be expected to increase.

[0094] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

[0095] [Explanation of symbols]

[0096] 100: Electrode manufacturing device

[0097] 110 (111, 112, 113, 114): Multiple calendaring rolls

[0098] 120 (121, 122, 123, 124): Multiple axes of rotation

[0099] 126 (1261, 1262, 1263, 1264): Guards

[0100] 127 (1271, 1272, 1273, 1274): Distal

[0101] 130 (131, 132, 133, 134): Multiple housings

[0102] 140 (141, 142, 143, 144): Multiple bearing parts

[0103] 150(151, 152, 153): Multiple connecting elements

Claims

1. A plurality of calendaring rolls arranged at predetermined intervals so that electrode sheets are rolled sequentially; a plurality of rotating shafts extending from both ends of each of the plurality of calendaring rolls; and A housing including an opening through which the rotation axis passes, Each of the above rotation axes has a distal portion positioned on the opening and supported by the housing; and Including a proximal portion located between the above calendaring roll and the distal portion, An electrode manufacturing device, wherein the diameter of the proximal portion connected to at least one of the plurality of calendaring rolls is different from the diameter of the proximal portion connected to the remaining calendaring rolls.

2. In paragraph 1, An electrode manufacturing device, wherein the diameter of the proximal portion connected to at least one of the plurality of calendaring rolls is determined based on the magnitude of the linear pressure exerted by the at least one calendaring roll.

3. In paragraph 2, An electrode manufacturing device, wherein the diameter of the proximal portion connected to the calendering roll located at the uppermost end in the direction of travel of the electrode sheet among the plurality of calendering rolls is larger than the diameter of the proximal portion connected to the remaining calendering rolls.

4. In paragraph 2, An electrode manufacturing device, wherein the diameter of the proximal part connected to the second-positioned calendering roll based on the direction of travel of the electrode sheet among the plurality of calendering rolls is larger than the diameter of the proximal part connected to the remaining calendering rolls except for the calendering roll located at the top.

5. In paragraph 2, An electrode manufacturing device, wherein the diameter of the proximal portion connected to the calendering roll located at the lowermost end in the direction of travel of the electrode sheet among the plurality of calendering rolls is smaller than the diameter of the proximal portion connected to the remaining calendering rolls.

6. In paragraph 2, An electrode manufacturing device, wherein when the linear pressure of one of the plurality of calendaring rolls is greater than the linear pressure of another calendaring roll, the diameter of the proximal portion connected to one of the calendaring rolls is greater than the diameter of the proximal portion connected to the other calendaring roll.

7. In paragraph 6, An electrode manufacturing device, wherein the magnitude of the linear pressure applied by the plurality of calendaring rolls decreases toward the downstream of the moving direction.

8. In paragraph 6, An electrode manufacturing device in which the square of the diameter of the above-mentioned proximal portion has a linear relationship with the magnitude of the above-mentioned pressure.

9. In paragraph 1, An electrode manufacturing device, wherein each of the distal portions connected to the plurality of calendaring rolls has the same diameter.

10. In paragraph 1, An electrode manufacturing device, wherein the housing further includes a bearing portion formed on the opening portion to support the distal portion.

11. In paragraph 1, An electrode manufacturing device, wherein the housing includes a plurality of housings that individually support the rotational axis.

12. In paragraph 11, An electrode manufacturing device further comprising a connecting member disposed between two adjacent housings among the plurality of housings.

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