Apparatus for making dry electrode of rechargeable battery

Abstract

A secondary battery dry electrode forming apparatus is disclosed, comprising a frame in which rollers for forming an active material plate by receiving a composition and rollers for laminating between the active material plate and a current collector are mounted together, such that at least some of the rollers move in a specific direction, i.e., in a one-dimensional manner. In the forming apparatus of the present invention, the frame comprises a guide portion for connecting rollers or pairs of rollers for forming an active material plate to move in a one-dimensional manner, and a guide portion for connecting rollers or pairs of rollers for lamination to move in a one-dimensional manner. According to the present invention, rollers for forming an active material plate and rollers for lamination can be managed together, and since only one-dimensional travel distance is managed, management can be made easier.

Description

Technology Field

[0001] The present invention relates to an electrode forming apparatus for a secondary battery, and more specifically, to a dry electrode forming apparatus for a secondary battery. Background Technology

[0002] A secondary battery is comprised of a negative electrode, a positive electrode, and an electrolyte, and the negative or positive electrode is typically formed by stacking a negative active material or a positive active material on a metal current collector that is a conductor.

[0003] Previously, a common method for laminating active materials onto metal current collectors involved producing the active material in powder form, mixing it with a mixing medium to create a paste, coating the paste onto the current collector, and then vaporizing and removing the mixing medium.

[0004] However, this wet method had the disadvantage that a lot of heat had to be applied to vaporize and remove the mixed medium after coating the active material in the form of a paste, and a lot of time was required to make the paste or remove the mixed medium.

[0005] In addition, for the continuous process, there was a problem where the travel distance for the mixed medium vaporization process increased, leading to a greater burden on process equipment and space.

[0006] To alleviate these problems, a dry process is being developed in which, instead of forming a paste using a mixing medium when laminating an active material layer onto a current collector, a resin such as PVDF is mixed together with the active material in powder form when forming the active material layer, and then heated and pressed so that the PVDF acts as an adhesive to bind the active material to the current collector.

[0007] FIG. 1 is a conceptual diagram showing an example of a dry process for manufacturing such a secondary battery (Korean Patent Application No. 10-2022-0040063).

[0008] Here, a composition for dry electrode active material is supplied in powder form between two adjacent pairs of rollers to form a pair of active material sheets or active material plates, and these active material plates are supplied together with a separately supplied current collector sheet between two adjacent rollers of the two pairs of rollers and laminated together by heating and pressurizing to form an electrode plate.

[0009] However, in such process equipment, the process of making active material plates must be carried out while precisely adjusting the spacing between each pair of rollers and the spacing between the two rollers used for lamination; since the positions of the rollers used are interrelated, it is not easy to accurately adjust the mutual spacing between them, which can lead to various problems.

[0010] FIG. 2 is a conceptual drawing showing an example of another dry process (Korean Patent Application No. 10-2023-0052330).

[0011] Here, a composition for electrode active material is supplied between a pair of rolling rolls to form a primary active material plate, and this is supplied to another rolling roll to form a secondary active material plate, which is then wound on another roller to form an active material roll. The active material roll thus formed undergoes a lamination process together with a separately supplied current collector, as shown in FIG. 3, to form an electrode plate.

[0012] FIG. 4 discloses a secondary battery electrode forming process and apparatus or system representing another example of a conventional dry process (Korean Patent Application No. 10-2021-0165931).

[0013] Here, the part that forms the active material plate through rolling, the part that subsequently processes the formed active material plate to achieve desired thickness, density, porosity, surface roughness, etc., the part that supplies the current collector, and the part that laminates the current collector and the active material plate to form an electrode are all separate parts, and these are combined to form an electrode.

[0014] In such a system, there is a problem in that a lot of time and effort is required to combine and adjust each part.

[0015] For electrodes used in secondary batteries, it is important to uniformly control the thickness and density of the active material layer. To achieve this, the gap between rollers in the dry coating process using rollers must be precisely controlled, and the gap between rollers must be rapidly controlled in real time to respond to moment-by-moment changes in process conditions.

[0016] In addition, efforts are required to improve the working environment and reduce production costs by precisely controlling the gap between rollers while reducing the volume of the device.

[0017] However, as shown above, prior art regarding secondary battery dry electrode forming devices, including the prior art, has not made it easy to efficiently control the gap between the rollers for forming the active material plate and the rollers for lamination. Therefore, there is a demand for a dry electrode manufacturing device that can make process operation more efficient by easily adjusting the rollers for forming the active material plate and the rollers for laminating the active material plate and the current collector according to the situation when forming the secondary battery dry electrode. Prior art literature

[0018] Republic of Korea Patent Application No. 10-2022-0040063 Republic of Korea Patent Application No. 10-2023-0052330 Republic of Korea Patent Application No. 10-2021-0165931 The problem to be solved

[0019] The present invention aims to provide a secondary battery dry electrode forming device that allows for easy position adjustment of rollers for lamination and active material plates, thereby mitigating problems in the prior art.

[0020] The present invention aims to provide a secondary battery dry electrode forming device that allows rollers for forming an active material plate and rollers for lamination to be combined and managed together, and facilitates such management. means of solving the problem

[0021] The secondary battery dry electrode forming apparatus of the present invention for achieving the above objective is,

[0022] It is provided with a frame in which rollers for receiving a composition to form an active material plate and rollers for laminating between the active material plate and the current collector are mounted together, such that at least some of the rollers move in a specific direction, that is, in a one-dimensional manner.

[0023] In the forming device of the present invention, the frame has both a guide portion that combines rollers for forming an active material plate to move in one dimension and a guide portion that combines rollers for lamination to move in one dimension.

[0024] The forming device of the present invention may be provided with a transfer means capable of moving at least some of the rollers for forming an active material plate along a guide portion, and a transfer means capable of moving at least some of the rollers for lamination along a guide portion.

[0025] In the present invention, a support member may be provided to rotatably support the roller and to be coupled to the guide portion so as to be transportable in one dimension in order to transport the roller along the guide portion.

[0026] In this case, various known electrical, electronic, or mechanical linear actuators can be used as the means of transport to move the support body along the guide section. For example, to move the support body left and right along the guide section, a mechanism can be used in which a screw assembly and an electric motor are utilized such that when the electric motor rotates, one side of the screw assembly rotates while the other side of the screw assembly moves in a linear motion.

[0027] One-dimensional movement of the support body can be achieved, for example, by sliding or wheel rolling in the left-right direction on the drawing, but to prevent movement in other dimensions during transport, for example, guide parts may be installed vertically on the support body to prevent vertical movement of the support body, and more preferably, may also be installed at the front and back of the support body to prevent forward and backward movement.

[0028] The forming device of the present invention may be equipped with a spacing adjustment means capable of adjusting the spacing between the two rollers closest to each other among the rollers for forming an active material plate and the rollers for lamination.

[0029] The gap adjustment means may be provided with a first inclined section that contacts one of the two closest rollers, a second inclined section that contacts the other side and has a second inclined section that can move up and down along the first inclined surface of the first inclined section, and a gap adjustment driving unit that contacts or is coupled to at least one of these inclined sections to move the inclined section up and down along the inclined surface.

[0030] At this time, the gap adjustment drive unit may be provided with a screw moving part that moves along an inclined surface to push the inclined part to widen the gap between the two rollers, an electric motor having a rotating shaft coupled to the screw moving part to rotate the screw moving part in a first direction, and an elastic body that contracts by contacting or coupled to the inclined part when the inclined part moves, and restores itself to move along an inclined surface to narrow the gap between the two rollers when the screw moving part rotates in a second direction. Effects of the invention

[0031] According to the present invention, the positioning of rollers for forming and laminating active material plates can be easily adjusted.

[0032] According to the present invention, rollers for forming an active material plate and rollers for lamination can be combined and managed together, and such management can be facilitated. Brief explanation of the drawing

[0033] FIG. 1 is a conceptual diagram showing a conceptually simplified part of a conventional secondary battery dry electrode forming device. FIG. 2 is a conceptual diagram showing a part of a conventional dry electrode forming device for other secondary batteries. FIG. 3 is a conceptual diagram showing the lamination of a current collector and an active material plate in another part of the secondary battery dry electrode forming device of FIG. 2. FIG. 4 is a conceptual diagram showing the configuration of a conventional dry electrode forming device for a secondary battery. FIGS. 5 and FIGS. 6 are conceptual diagrams illustrating the configuration of a secondary battery dry electrode forming apparatus according to an embodiment of the present invention. Specific details for implementing the invention

[0034] The present invention will be described in more detail through specific embodiments with reference to the drawings below.

[0035] FIG. 5 illustrates a secondary battery dry electrode forming apparatus constituting an embodiment of the present invention. Here, the forming apparatus comprises a pair of active material plate forming rollers (310) for forming an active material plate by receiving a dry active material composition, a pair of laminating rollers (410) for laminating between the active material plate and a current collector, an active material supply unit (510) for supplying a dry active material composition to the pair of active material plate forming rollers (310), a current collector supply unit (610) for supplying a current collector to the pair of laminating rollers (410), an active material roller support (320) for rotatably supporting a roller in at least one of the pairs of active material plate forming rollers (310), a laminating roller support (420) for rotatably supporting a roller in at least one of the pairs of laminating rollers (410), a frame (700) configured to support these roller supports and move in a one-dimensional manner, in this case, in the left and right directions, and a transfer means for moving each of these supports within the frame.

[0036] Referring to the drawing, more specifically, the frame (700) is an integral frame that forms a roughly rectangular guide space (710) on which supports are placed for each of the rollers forming the active material plate forming roller pair (310), and a roughly rectangular guide space (720) on which supports are placed for each of the rollers forming the laminating roller pair (410). In this frame, the two guide spaces are also arranged in the left-right direction relative to each other, so that the rollers are all arranged in a line relative to each other in the left-right direction.

[0037] Within this frame (700), two adjacent rollers (310a, 410a) among the two pairs of rollers also have supports, but these supports are fixed in the guide space, and the supports of the remaining rollers (310b, 410b) are configured to move only in the left and right directions along the guide space. In this sense, the upper and lower edges of the frame portion surrounding the guide space can be seen here as guide portions that guide the supports left and right, i.e., guide portions.

[0038] At this time, the one-dimensional support body transfer is carried out by sliding in the left and right directions on the drawing, but it can also be carried out by a wheel-rolling method using wheels formed on the support body and rails formed on the guide part, rather than by a sliding method.

[0039] In addition, to prevent movement in other dimensions during transport—that is, to prevent movement in the up-down and front-back directions excluding left-right movement—the guide portion may be installed at the top and bottom of the support body, as well as at the front-back positions of the support body.

[0040] In this embodiment, the transfer means is installed on the frame (700) and is configured to include a screw assembly (810) and an electric motor (820: servo motor) for rotating one side of the screw assembly to move the support body left and right along the guide portion; however, in addition to this means, various mechanical, electrical, and electronic linear actuators may be used, and since these means are well known, a description of their specific configuration and operation will be omitted.

[0041] If we examine the process of forming the active material plate and laminating it with the current collector in this embodiment,

[0042] First, a step is performed to check and adjust the gap between the two rollers in the laminating roller pair (410) and the active material plate forming roller pair (310). At this time, when the electric motor (820) rotates by a certain displacement to adjust the gap, one side of the screw assembly (810) rotates and the other side of the screw assembly is fixed, so that as a result, one side of the screw assembly moves in the direction of the screw axis and moves the support attached thereto. When the support moves, the roller supported by the support also moves in the same direction, and the other roller among the two rollers forming the roller pair is likewise fixed because the support associated with it is fixed within the guide space, and as a result, the gap between the two rollers in the roller pair can be adjusted.

[0043] Although not described in detail here, there is an active material supply unit (510) that supplies an active material composition to the pair of active material plate forming rollers (310). The active material composition is supplied in a powder or granular form suitable for a dry electrode and may comprise an active material, a conductive agent to smoothly transfer the charge generated from the active material to the current collector, and a binder such as PVDF to form the active material composition into a single electrode plate. Each support is equipped with a motor capable of rotating the rollers. When these motors are operated and the rollers rotate, the active material composition passing between the rollers is subjected to heat and pressure to form an active material plate having characteristics such as desired thickness, density, and porosity.

[0044] The active material plate is supplied directly between the laminating roller pair (410) and overlaps with the current collector in the supply path. This current collector is supplied from a current collector roll installed in a separate current collector supply unit (610). When the current collector and the active material plate pass between the two rollers of the laminating roller pair while overlapping, they are heated and pressurized so that the active material plate is firmly bonded to the current collector, thereby forming a dry electrode with the desired thickness and properties.

[0045] In this embodiment, in each of the laminating roller pair and the active material plate forming roller pair, the two rollers forming the pair are supported by a support, and one of the two rollers is fixed together with the support while the other moves in one direction together with the support along a guide space or guide section, and the gap between the two rollers can be easily adjusted. Therefore, properties such as the thickness and density of the active material plate, and the thickness and properties of the electrode can be easily controlled and obtained.

[0046] FIG. 6 is a conceptual diagram illustrating another embodiment of the present invention.

[0047] In the embodiment of FIG. 5, a guide space (720) for installing a laminating roller pair (410) and a guide space (710) for installing an active material plate forming roller pair (310) are arranged in a left-right direction relative to each other, and the rollers are all arranged in a line relative to each other in a left-right direction. The two guide spaces are separated by a separate wall (730), and the support body of one roller (310a, 410a) forming the roller pair is fixed in position by this wall (730), but here, instead of a wall with a constant thickness between the two guide spaces, a spacing adjustment means is provided so that the thickness is variable.

[0048] In this frame (700), the two guide spaces (710, 720) are also arranged in the left and right directions relative to each other, and the rollers are all arranged in a line relative to each other in the left and right directions.

[0049] By means of such spacing adjustment means, the spacing between two adjacent rollers (310a, 410a) in the middle of the rollers for forming the active material plate and the rollers for laminating can be adjusted.

[0050] The gap adjustment means comprises a first inclined section (910) that contacts one of the two closest rollers, a second inclined section (920) that contacts the other side and has a second inclined surface that can move up and down along the first inclined surface of the first inclined section, and a gap adjustment driving unit (930) that contacts or is coupled to at least one of the inclined sections to move the inclined section up and down along the inclined surface.

[0051] The gap adjustment drive unit is equipped with a screw moving unit (930) that moves along the inclined surface to push the inclined part (920) to widen the gap between the two rollers.

[0052] The screw moving part (930) may be manually controlled by an operator, but may also be precisely controlled by a servo motor having a rotation axis that is coupled to the screw moving part and rotates the screw moving part in a first rotation direction.

[0053] In addition, the gap adjustment drive unit may be equipped with an elastic body (not shown) that contracts by contacting or engaging with the inclined part when the inclined part moves, and restores the inclined surface to narrow the gap between the two rollers when the screw moving part rotates in a second rotational direction, thereby facilitating the smooth performance of the operation when the inclined part is restored to its original position after moving.

[0054] In the embodiment of FIG. 6, the configuration and operation of the conveying means for adjusting the gap between the two rollers in the laminating roller pair and the active material plate forming roller pair can be performed as in the embodiment of FIG. 5.

[0055] In this embodiment, the process of forming the active material plate and laminating it with the current collector can be carried out substantially the same as in the embodiment of FIG. 5. However, in the embodiment of FIG. 5, the active material plate formed by supplying the active material composition to the pair of active material plate forming rollers may be supplied directly between the pair of laminating rollers; however, the active material plate may be supplied between two rollers whose mutual spacing is adjusted by a spacing adjustment means, passed through once more to be rolled to form it with more suitable properties, and then supplied to the pair of laminating rollers to be bonded with the current collector, thereby allowing the active material plate forming process to be designed more appropriately to suit the purpose.

[0056] In any of the above cases, in this embodiment, the rollers can all move in only one direction, here in the left and right direction, along the guide portion (guide section) within the guide space, and thus the spacing between the rollers through which the active material plate passes needs to be adjusted in only one direction, making the adjustment very simple and easy. Therefore, properties such as the thickness and density of the active material plate, and the thickness and properties of the electrode can be easily adjusted and obtained.

[0057] Meanwhile, in the above embodiments, the servo motor responsible for rotating the rollers within the support and controlling the rotational speed adjusts the rotation radius and linear speed of each roller so that they become an appropriate speed when the active material plate passes, and so as to match the linear speed of the corresponding roller of the roller pair through which the active material plate passes.

[0058] Although the present invention has been described above through limited embodiments, this is merely illustrative to aid in understanding the invention, and the present invention is not limited to these specific embodiments. Accordingly, a person skilled in the art may make various modifications or applications based on the present invention, and such modifications or applications are naturally included within the scope of the appended claims. Explanation of the symbols

[0059] 310: Pair of active material plate forming rollers 320: Support (active material roller support) 410: Laminating roller pair 420: Support (Laminating roller support) 510: Active material supply unit 610: Current collector supply unit 700: Frame 710, 720: Guide space 810: Screw assembly 820: Motor 910: 1st Slope 920: 2nd Slope 930: Screw moving part

Claims

Claim 1 A pair of active material plate forming rollers for forming an active material plate by receiving a dry active material composition; a pair of laminating rollers for laminating between an active material plate and a current collector; an active material supply unit for supplying a dry active material composition to the pair of active material plate forming rollers; a current collector supply unit for supplying a current collector to the pair of laminating rollers; an active material roller support member rotatably supporting at least one roller among the pair of active material plate forming rollers; a laminating roller support member rotatably supporting at least one roller among the pair of laminating rollers; a frame in which the active material roller support member and the laminating roller support member are installed, wherein a guide space for the pair of active material plate forming rollers and a guide space for the pair of laminating rollers are separated by a gap adjustment means, and a first roller, which is one of the rollers of the pair of active material plate forming rollers, and a second roller adjacent to the first roller among the rollers of the pair of laminating rollers move in one direction by means of the gap adjustment means, thereby enabling adjustment of the gap between the two rollers. A secondary battery dry electrode forming apparatus comprising: a transfer means for moving the active material roller support and the laminating roller support, respectively, within the frame; wherein the transfer means is installed in the frame and comprises a screw coupling, an electric motor for rotating one side of the screw coupling, and a linear actuator to move the support left and right along a guide portion. Claim 2 A secondary battery dry electrode forming apparatus according to claim 1, wherein the frame is an integral frame forming a guide space in which supports are placed for each of the rollers forming the active material plate forming roller pair, and a guide space in which supports are placed for each of the rollers forming the laminating roller pair, wherein the supports for two adjacent rollers of the active material plate forming roller pair and the laminating roller pair are fixed to the respective guide space, and the supports for the remaining two rollers are configured to move only in the left and right directions along the respective guide space. Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 A secondary battery dry electrode forming device according to claim 1, wherein the gap adjustment means comprises a first inclined part that contacts one of the first roller and the second roller, a second inclined part having a second inclined surface that can move up and down along the first inclined surface of the first inclined part while contacting the other side, and a gap adjustment driving part that contacts or is coupled to at least one of the first inclined part and the second inclined part to cause the inclined part of one side to move up and down along the inclined surface of the inclined part of the other side. Claim 7 A secondary battery dry electrode forming device according to claim 6, wherein the gap adjustment driving unit comprises a screw moving part (screw coupling part) that moves along an inclined surface to push one inclined part to widen the gap between the first roller and the second roller, an electric motor having a rotating shaft coupled to the screw moving part to rotate the screw moving part in a first rotational direction, and an elastic body that contracts or stretches when the one inclined part moves by contacting or coupling with the one inclined part, and restores to move along an inclined surface to narrow the gap between the first roller and the second roller when the screw moving part rotates in a second rotational direction.

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