Coating apparatus for electrode substrate of rechargeable battery

Abstract

A coating apparatus for an electrode substrate of a rechargeable battery includes: a roller configured to continuously supply an electrode substrate; and a slit mold configured to form an active material coating portion on the electrode substrate. The roller and the slit mold form a first gap between each other at a center in a width direction of the electrode substrate and form a second gap larger than the first gap between each other at both ends in the width direction of the electrode substrate.

Description

Technical Field

[0001] Aspects of embodiments of the present disclosure are directed to a coating apparatus for an electrode substrate of a rechargeable battery. Background Art

[0002] Unlike primary batteries, rechargeable batteries are batteries designed to be repeatedly charged and discharged. Small-capacity rechargeable batteries can be used in portable small electronic devices such as mobile phones, laptop computers or cameras, while large-capacity rechargeable batteries can be used as a power source for driving motors of hybrid vehicles or electric vehicles.

[0003] A rechargeable battery generally includes an electrode assembly that performs charging and discharging, a package (e.g., a bag or a can) that accommodates the electrode assembly, and an electrode terminal electrically connected to the electrode assembly to lead the electrode assembly out of the package. The electrode assembly may be a wound electrode assembly in which a negative electrode plate and a positive electrode plate are wound on both sides of a separator interposed therebetween, or a stacked electrode assembly in which a negative electrode plate and a positive electrode plate are stacked on both sides of a separator interposed therebetween.

[0004] The electrode plate process for manufacturing the electrode plate generally includes a mixing step of mixing an active material slurry, a coating step of applying the active material slurry to a coating portion of an electrode substrate, a pressing step of compressing the active material slurry on the coating portion, and a slitting step of cutting the electrode substrate.

[0005] The positive electrode plate and the negative electrode plate manufactured by the electrode plate process face each other for operation. The ratio of positive electrode to negative electrode in a rechargeable battery is important to ensure safety. The capacity of the negative electrode should be greater than that of the positive electrode. In other words, if there is space for lithium ions to be embedded in the negative electrode active material, side reactions can be avoided or prevented.

[0006] However, according to the conventional slot die coating method, the amount of coating on the edge portion is relatively small. Insufficient coating may increase resistance by increasing the face-to-face distance between the positive electrode and the negative electrode, and may deteriorate safety due to phenomena caused by imbalance of face-to-face capacity (e.g., reversal phenomenon). In other words, a shape that maintains a face-to-face distance and a uniform amount of active material in all regions is required.

[0007] The flow rate can be controlled by rheological control and shape changes of the spacers inside the slot die. However, there is a difference between the sliding shape of the coating edge portion and the amount of active material. Summary of the invention

[0008] Embodiments of the present disclosure provide a coating apparatus for an electrode substrate of a rechargeable battery, which reduces or minimizes a difference in an amount of active material coated between a coating center portion and a coating edge portion by controlling a shape of the coating edge portion and an amount of active material coated.

[0009] Other embodiments of the present disclosure provide a coating apparatus for an electrode substrate of a rechargeable battery, which ensures a safe face-to-face ratio between positive and negative electrodes and maintains a constant face-to-face distance by controlling the shape of a coating edge portion and a coating amount of an active material.

[0010] According to an embodiment of the present disclosure, a coating device for an electrode substrate of a rechargeable battery includes: a roller configured to continuously supply an electrode substrate; and a slit die configured to form an active material coating portion on the electrode substrate. The roller and the slit die form a first gap between each other at the center in the width direction of the electrode substrate and form a second gap larger than the first gap between each other at both ends in the width direction of the electrode substrate.

[0011] The first gap may be between a slit in the slot die and the electrode substrate on the roller.

[0012] The roller may have a non-corresponding portion extending beyond the slot die, and the non-corresponding portion corresponding to an end portion of the slit in the slot die may have a small diameter portion.

[0013] The second gap may be formed between the end portion of the slit in the slot die and the small diameter portion of the roller.

[0014] The small diameter portion may have: a truncated conical surface inclined away from the end portion of the slit of the slot die; and a cylindrical surface extending from the truncated conical surface in an axial direction of the roller.

[0015] The small diameter portion may have: a truncated conical surface formed as a convexly curved surface gently inclined and then steeply inclined away from the end portion of the slit in the slot die; and a cylindrical surface extending from the truncated conical surface in the axial direction of the roller.

[0016] The small diameter portion may have: a truncated conical surface formed as a concave curved surface that is steeply inclined and then gently inclined away from the slit in the slot die; and a cylindrical surface extending from the truncated conical surface in the axial direction of the roller.

[0017] The roller may have a non-corresponding portion extending beyond the slot die, and both ends of the slit in the slot die may have expanded slits corresponding to portions of the roller adjacent to the non-corresponding portion.

[0018] The second gap may be formed between the expanded slits at the both ends of the slit in the slot die and the portion of the roller adjacent to the non-corresponding portion.

[0019] The expansion slit may have an inclined portion inclined away from the roller and a planar portion extending from the inclined portion in an axial direction of the roller.

[0020] The expansion slit may have an inclined portion formed as a convexly curved surface gently inclined away from the roller and then steeply inclined, and a flat portion extending from the inclined portion in the axial direction of the roller.

[0021] The expansion slit may have an inclined portion formed as a concave curved surface that is steeply inclined away from the roller and then gently inclined, and a flat portion extending from the inclined portion in the axial direction of the roller.

[0022] The embodiment of the present disclosure can form a first gap between the roller and the slit die at the center in the width direction of the electrode substrate, and can form a second gap larger than the first gap at both ends in the width direction of the electrode substrate, thereby controlling the shape of the coating edge portion and the coating amount of the active material. Therefore, the embodiment of the present disclosure can reduce or minimize the difference in the coating amount of the active material between the coating center portion and the coating edge portion.

[0023] An embodiment of the present disclosure may form a first gap at the center of the electrode substrate in the width direction, and may form a second gap larger than the first gap at both ends of the electrode substrate in the width direction to control the shape of the coated edge portion and the coating amount of the active material, thereby ensuring a safe face-to-face ratio between the positive electrode and the negative electrode and maintaining a constant face-to-face distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a cross-sectional view of a coating apparatus for an electrode substrate of a rechargeable battery according to an embodiment of the present disclosure.

[0025] Figure 2 Including showing the application of active substances to Figure 1 The roll-supplied electrode substrate is shown in various figures.

[0026] Figure 3 is a state diagram illustrating a first gap and a second gap between a roller and a slot die in a coating apparatus for an electrode substrate of a rechargeable battery according to another embodiment of the present disclosure.

[0027] Figure 4 is a state diagram illustrating a first gap and a second gap between a roller and a slot die in a coating apparatus for an electrode substrate of a rechargeable battery according to another embodiment of the present disclosure.

[0028] Figure 5 A diagram illustrating a state in which an active material is applied to an electrode substrate supplied by a roll using a slit die in a coating apparatus for an electrode substrate for a rechargeable battery according to another embodiment of the present disclosure.

[0029] Figure 6 is a state diagram illustrating a first gap and a second gap between a roller and a slot die in a coating apparatus for an electrode substrate of a rechargeable battery according to another embodiment of the present disclosure.

[0030] Figure 7 is a state diagram illustrating a first gap and a second gap between a roller and a slot die in a coating apparatus for an electrode substrate of a rechargeable battery according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0031] The present disclosure will be described more fully hereinafter with reference to the accompanying drawings showing embodiments of the present disclosure. As will be appreciated by those skilled in the art, the described embodiments can be modified in various ways without departing from the spirit or scope of the present disclosure. The accompanying drawings and descriptions should be considered as illustrative rather than restrictive in nature. Throughout the specification, the same reference numerals designate the same elements.

[0032] It will be understood that when an element or layer is referred to as being "on," "connected to," or "coupled to" another element or layer, it may be directly on, connected to, or coupled to the other element or layer, or there may be one or more intervening elements or layers. When an element or layer is referred to as being "directly on," "directly connected to," or "directly coupled to" another element or layer, there may be no intervening elements or layers. For example, when a first element is described as being "coupled to" or "connected to" a second element, the first element may be directly coupled to or connected to the second element, or the first element may be indirectly coupled to or connected to the second element via one or more intervening elements.

[0033] In the figures, for clear illustration, the sizes of various elements, layers, etc. can be enlarged. The same reference numerals indicate the same elements. As used herein, the term "and / or" includes any and all combinations of one or more related listed items. Further, when describing an embodiment of the present disclosure, the use of "may" relates to "one or more embodiments of the present disclosure". Statements such as "at least one of" and "any one of", when after a column of elements, modify the entire column of elements without modifying the single element in the column. For example, the statement "at least one of a, b, and c" means only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c or its variant. As used herein, the term "use" can be considered to be synonymous with the term "utilize". As used herein, the terms "substantially", "about" and similar terms are used as approximate terms rather than as degree terms, and are intended to take into account the inherent changes in measured values ​​or calculated values ​​that will be recognized by those of ordinary skill in the art.

[0034] It will be understood that although the terms "first", "second", "third", etc. may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Therefore, without departing from the teachings of the example embodiments, the first element, component, region, layer or section discussed below may be referred to as a second element, component, region, layer or section.

[0035] For ease of description, spatially relative terms such as "below," "below," "down," "above," "on," etc. may be used herein to describe the relationship of one element or feature to another element or feature as illustrated in the figure. It will be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is turned over, the elements described as being "below" or "below" other elements or features will then be oriented as being "above" or "on" other elements or features. Therefore, the term "below" may include both above and below orientations. The device may be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0036] The terms used herein are for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, as used herein, the singular form "a" is intended to also include the plural form. It will be further understood that the terms "include" and / or "comprise" when used in this specification specify the presence of stated features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or their groups.

[0037] Figure 1 is a cross-sectional view of a coating apparatus for an electrode substrate of a rechargeable battery according to an embodiment of the present disclosure, and Figure 2 The active substance is applied to the Figure 1 , a plan view (a) of the step of roller-supplied electrode substrate, a cross-sectional view (b) of the shape of the coated active material coating portion, and cross-sectional views (c) and (d) of the portion where the negative electrode and the positive electrode face each other.

[0038] refer to Figure 1 and Figure 2 , a coating apparatus 1 for an electrode substrate of a rechargeable battery according to an embodiment may include a roller 10 continuously supplying an electrode substrate S and a slit die 20 configured to form an active material coating portion CP at (or on) the electrode substrate S. The roller 10 may move the electrode substrate S toward the slit die 20 to coat the active material while rotating, and then may move the electrode substrate S away from the slit die 20.

[0039] For example, the slot die 20 may include a first block 21, a second block 22, and a spacer member (e.g., a spacer) installed between the first block 21 and the second block 22. The first block 21, the second block 22, and the spacer member installed between the first block 21 and the second block 22 may be fastened with a fastening member to form the slot die 20 for coating the active material slurry.

[0040] The first block 21 may include a chamber 201 that stores (e.g., temporarily stores) the supplied active material slurry to uniformly supply the stored active material slurry in the width direction. A supply portion (e.g., a supply unit) may be connected to a lower portion of the first block 21 to supply the active material slurry to the chamber 201. The first block 21 and the second block 22 coupled to each other may form a split (or opening or slit) 23 for discharging the active material slurry.

[0041] The slit die 20 may temporarily contain the active material slurry supplied through the supply portion in the chamber 201 before discharging the contained active material slurry through the slit 23, so that the slit die 20 applies a uniform or substantially uniform amount of the active material slurry to the electrode substrate S traveling in front of the slit 23 in the width direction. Therefore, a coating portion CP on which the active material slurry is coated and an uncoated portion UCP on both sides (e.g., opposite sides) of the coating portion CP on which the active material slurry is not coated and the electrode substrate S is exposed are formed at (or on) the electrode substrate S.

[0042] Based on the width direction of the electrode substrate S, in the coating portion CP, a coating center portion C1 may be formed at the center in the width direction, and coating edge portions C2 may be formed at both ends of the coating portion CP in the width direction on both sides of the coating center portion C1.

[0043] The illustrated embodiment can control the shape of the coating edge portion C2 and the coating amount of the coating edge portion C2 to reduce the difference in coating amount between the coating center portion C1 and the coating edge portion C2, thereby ensuring the stability of the rechargeable battery by making the face-to-face distance between the positive electrode and the negative electrode uniform or substantially uniform.

[0044] The roller 10 and the slot die 20 may form a first gap G1 between the roller 10 and the slot die 20 at the center in the width direction of the electrode substrate S and may form a second gap G2 greater than the first gap G1 between the roller 10 and the slot die 20 at both ends in the width direction of the electrode substrate S. The first gap G1 and the second gap G2 may be provided between the slit 23 in the slot die 20 and the electrode substrate S traveling on (or along) the roller 10.

[0045] The first gap G1 and the second gap G2 may allow the coating amount of the active material to be constant or substantially constant when the active material slurry of each of the positive electrode and the negative electrode is coated on the electrode substrate S. For example, the first gap G1 may keep the coating amount and the coating height (H) relatively constant in the coating center portion C1, and the second gap G2 may keep the coating amount of the coating edge portion C2 at the same level or substantially the same level as the coating amount of the coating center portion C1.

[0046] Therefore, the coating amount and coating height (H) of the active material slurry in the region where the positive electrode E1 and the negative electrode E2 face each other may be uniform or substantially uniform. For example, in the illustrated embodiment (d), the coating amount and coating height (H) of the active material slurry in the region where the positive electrode E1 and the negative electrode E2 face each other may be more uniform than the coating amount and coating height (H) of the active material slurry in the region where the positive electrode E11 and the negative electrode E21 face each other in the conventional example (c), thereby improving the stability of the rechargeable battery.

[0047] refer to Figure 2 For example, the roller 10 may have a corresponding portion 11 corresponding to the slot die 20 and a non-corresponding portion 12 formed longer than the slot die 20 (eg, outside or beyond the slot die 20 ) so as not to correspond to the slot die 20 .

[0048] The slit die 20 and the roller 10 may form a first gap G1 between each other in the corresponding portion 11. For example, the slit 23 in the slit die 20 and the electrode substrate S may form the first gap G1 between each other in the corresponding portion 11. The first gap G1 may form a coating center portion C1 by making the coating amount of the active material slurry constant or substantially constant in the corresponding portion 11.

[0049] The non-corresponding portion 12 of the roller 10 may have a small diameter portion 121 having a diameter smaller than that of the corresponding portion 11. The small diameter portion 121 may be formed at the non-corresponding portion 12 corresponding to both ends of the slit 23 in the slot die 20. For example, the small diameter portion 121 may start from a connection portion between the corresponding portion 11 and the non-corresponding portion 12, and may be formed throughout the non-corresponding portion 12.

[0050] As an example, the small diameter portion 121 may have a truncated conical surface 122 inclined away from the end portion of the slit 23 of the slot die 20 and a cylindrical surface 123 connected to the truncated conical surface 122 (eg, extending from the truncated conical surface 122 ) in the axial direction of the roller 10 .

[0051] The slit die 20 and the roller 10 may form a second gap G2 between each other in the non-corresponding portion 12. For example, in the small diameter portion 121 of the non-corresponding portion 12, the cleft 23 in the slit die 20 and the electrode substrate S may form the second gap G2 between each other. For example, the second gap G2 may be formed between the end portion of the cleft 23 in the slit die 20 and the small diameter portion 121 of the roller 10. The second gap G2 may be formed in the coating edge portion C2 by increasing the coating amount of the active material slurry in the non-corresponding portion 12 compared to the coating amount of the active material slurry in the coating center portion C1.

[0052] The truncated conical surface 122 in the small diameter portion 121 can gradually increase the first gap G1 to the second gap G2 to prevent a sharp increase in the coating amount on the cylindrical surface 123. Therefore, the truncated conical surface 122 connecting the corresponding portion 11 and the cylindrical surface 123 can provide (or form) a gradual increase in the coating amount in each of the coating center portion C1 and the coating edge portion C2.

[0053] Due to the first and second gaps G1 and G2 formed by the truncated conical surface 122 and the cylindrical surface 123 of the small diameter portion 121 , the coating amount of the active material slurry in the coating edge portion C2 may be increased compared to the coating center portion C1 .

[0054] The coating center portion C1 and the coating edge portion C2 may form the same level of coating amount and the same coating height (H). For example, the coating amount and coating height (H) of the active material slurry may be uniform or substantially uniform in the region where the positive electrode E1 and the negative electrode E2 face each other.

[0055] Therefore, when the electrode substrate S is used in the electrode assembly of the rechargeable battery, the face-to-face distance and face-to-face capacity between the positive electrode and the negative electrode in the rechargeable battery can be constant. Accordingly, the resistance can be reduced at the portion where the negative electrode and the positive electrode face each other, and safety can be ensured.

[0056] Hereinafter, various embodiments of the present disclosure will be described. The same description of the embodiments as those described above may be omitted, and the description of the embodiments different from those described above will be mainly described.

[0057] Figure 3 2 is a state diagram illustrating a first gap and a second gap between a roller and a slit die in a coating apparatus for an electrode substrate of a rechargeable battery according to another embodiment of the present disclosure. Figure 3 In the coating device 2 according to this embodiment, the small diameter portion 221 may have a truncated conical surface 222 and a cylindrical surface 223, the truncated conical surface 222 having a convex surface that is gently inclined and then sharply inclined away from the end portion of the slit 23 in the slit die 20, and the cylindrical surface 223 is connected to the truncated conical surface 222 in the axial direction of the roller 210 (for example, extends from the truncated conical surface 222).

[0058] In the non-corresponding portion 212, the slit die 20 and the roller 210 may form a second gap G22 between each other. For example, in the small diameter portion 221 of the non-corresponding portion 212, the slit 23 in the slit die 20 and the electrode substrate S2 may form a second gap G22 between each other. The second gap G22 may be formed by Figure 2 The amount of active material slurry applied in the coating center portion C1 shown in FIG. 1 is increased compared to the amount of active material slurry applied in the non-corresponding portion 212 to form Figure 2 The coated edge portion C2 is shown in FIG.

[0059] The truncated conical surface 222 in the small diameter portion 221 may gradually (e.g., gently or slowly) increase the first gap G1 toward the second gap G22, and then may sharply increase to the second gap G22 to prevent a sharp increase in the coating amount on the cylindrical surface 223. Therefore, the truncated conical surface 222 connecting the corresponding portion 211 and the cylindrical surface 223 (or extending between the corresponding portion 211 and the cylindrical surface 223) may provide a gradual increase in the coating amount in each of the coating center portion C1 and the coating edge portion C2.

[0060] Due to the first and second gaps G1 and G22 formed by the truncated conical surface 222 and the cylindrical surface 223 of the small diameter portion 221 , the coating amount of the active material slurry in the coating edge portion C2 may be increased compared to the coating center portion C1 .

[0061] The coating center portion C1 and the coating edge portion C2 may form the same level of coating amount and the same coating height (H). For example, the coating amount and coating height (H) of the active material slurry may be uniform or substantially uniform in the region where the positive electrode E1 and the negative electrode E2 face each other.

[0062] Therefore, when the electrode substrate S2 is used in the electrode assembly of the rechargeable battery, the face-to-face distance and face-to-face capacity between the positive electrode and the negative electrode in the rechargeable battery can be constantly ensured. Accordingly, the resistance can be reduced at the portion where the negative electrode and the positive electrode face each other, and safety can be ensured.

[0063] Figure 4 2 is a state diagram illustrating a first gap and a second gap between a roller and a slit die in a coating apparatus for an electrode substrate of a rechargeable battery according to another embodiment of the present disclosure. Figure 4 In the coating device 3 according to this embodiment, the small diameter portion 321 may have a truncated conical surface 322 and a cylindrical surface 323, the truncated conical surface 322 having a concave surface that is sharply inclined away from the end portion of the slit 23 in the slit die 20 and then gently inclined, and the cylindrical surface 323 is connected to the truncated conical surface 322 in the axial direction of the roller 310 (for example, extends from the truncated conical surface 322).

[0064] In the non-corresponding portion 312, the slit die 20 and the roller 310 may form a second gap G32 between each other. For example, in the small diameter portion 321 of the non-corresponding portion 312, the slit 23 in the slit die 20 and the electrode substrate S3 may form a second gap G32 between each other. The second gap G32 may be formed by Figure 2The amount of active material slurry applied in the coating center portion C1 shown in FIG. 1 is increased compared to the amount of active material slurry applied in the non-corresponding portion 312 to form Figure 2 The coated edge portion C2 is shown in FIG.

[0065] The truncated conical surface 322 in the small diameter portion 321 may sharply increase the first gap G1 toward the second gap G32, and then may gradually increase the first gap G1 to the second gap G32 to prevent a sharp increase in the coating amount on the cylindrical surface 323. Therefore, the truncated conical surface 322 connecting the corresponding portion 311 and the cylindrical surface 323 may provide a gradual increase in the coating amount in each of the coating center portion C1 and the coating edge portion C2.

[0066] Due to the first and second gaps G1 and G32 formed by the truncated conical surface 322 and the cylindrical surface 323 of the small diameter portion 321 , the coating amount of the active material slurry in the coating edge portion C2 may be increased compared to the coating center portion C1 .

[0067] The coating center portion C1 and the coating edge portion C2 may form the same level of coating amount and the same coating height (H). For example, the coating amount and coating height (H) of the active material slurry may be uniform or substantially uniform in the region where the positive electrode E1 and the negative electrode E2 face each other.

[0068] Therefore, when the electrode substrate S3 is used in the electrode assembly of the rechargeable battery, the face-to-face distance and face-to-face capacity between the positive electrode and the negative electrode in the rechargeable battery can be constantly ensured. For this reason, the resistance can be reduced at the portion where the negative electrode and the positive electrode face each other, and safety can be ensured.

[0069] Figure 5 is a plan view illustrating that an active material is applied to an electrode substrate supplied by a roll using a slit die in a coating apparatus for an electrode substrate for a rechargeable battery according to another embodiment of the present disclosure. Figure 5 , in the coating apparatus 4 according to this embodiment, the roller 410 may have a corresponding portion 411 corresponding to the slot die 420 and a non-corresponding portion 412 formed longer than the slot die 420 so as not to correspond to the slot die 420 .

[0070] In the corresponding portion 411, the slit die 420 and the roller 410 may form a first gap G41 between each other. For example, in the corresponding portion 411, the slit 403 in the slit die 420 and the electrode substrate S4 may form a first gap G41 between each other. The first gap G41 may be formed by making the coating amount of the active material slurry constant in the corresponding portion 411. Figure 2 The coated center portion C1 is shown in FIG.

[0071] Both ends of the slit 403 in the slot die 420 may have an expanded slit (e.g., an expanded or enlarged opening) 421 corresponding to a portion of the roller 410 adjacent to the non-corresponding portion 412. The expanded slit 421 may start from a connection portion between the corresponding portion 411 and the non-corresponding portion 412 to be formed at a portion of the corresponding portion 411.

[0072] The second gap G42 may be formed between the expanded slit 421 at both ends of the slit 403 provided in the slot die 420 and the corresponding portion 411 adjacent to the non-corresponding portion 412 of the roller 410. The second gap G42 may form the coating edge portion C2 by increasing the coating amount of the active material slurry at both ends of the corresponding portion 411 adjacent to the non-corresponding portion 412 compared to the coating amount of the active material slurry in the coating center portion C1.

[0073] As an example, the expansion slit 421 may have an inclined portion 422 inclined away from the roller 410 and a plane portion 423 connected to (or extending from) the inclined portion 422 in the axial direction of the roller 410. The inclined portion 422 in the expansion slit 421 may gradually increase the first gap G41 to the second gap G42 to prevent a sharp increase in the coating amount in the plane portion 423. Therefore, the inclined portion 422 connecting the slit 403 and the plane portion 423 may provide a gradual increase in the coating amount in each of the coating center portion C1 and the coating edge portion C2.

[0074] Due to the first and second gaps G41 and G42 formed by the inclined portion 422 and the planar portion 423 of the expansion slit 421 , the coating amount of the active material slurry in the coating edge portion C2 may be increased compared to the coating center portion C1 .

[0075] The coating of the central portion C1 and the coating of the edge portion C2 can form the same level of coating amount and the same coating height (H) (see, for example Figure 2 ). For example, the coating amount and coating height (H) of the active material slurry may be uniform or substantially uniform in a region where the positive electrode E1 and the negative electrode E2 face each other.

[0076] Therefore, when the electrode substrate S4 is used in the electrode assembly of the rechargeable battery, the face-to-face distance and face-to-face capacity between the positive electrode and the negative electrode in the rechargeable battery can be constantly ensured. Accordingly, the resistance can be reduced at the portion where the negative electrode and the positive electrode face each other, and safety can be ensured.

[0077] Figure 62 is a state diagram illustrating a first gap and a second gap between a roller and a slit die in a coating apparatus for an electrode substrate of a rechargeable battery according to another embodiment of the present disclosure. Figure 6 , in the coating apparatus 5 according to this embodiment, the roller 410 may have a corresponding portion 411 corresponding to the slot die 520 and a non-corresponding portion 412 formed longer than the slot die 520 so as not to correspond to the slot die 520 .

[0078] In the corresponding portion 411, the slit die 520 and the roller 410 may form a first gap G41 between each other. For example, in the corresponding portion 411, the slit 503 in the slit die 520 and the electrode substrate S5 may form a first gap G41 between each other. The first gap G41 may be formed by making the coating amount of the active material slurry constant in the corresponding portion 411. Figure 2 The coated center portion C1 is shown in FIG.

[0079] Both ends of the slit 503 in the slot die 520 may have an expanded slit 521 corresponding to a portion of the roller 410 adjacent to the non-corresponding portion 412. The expanded slit 521 may start from a connection portion between the corresponding portion 411 and the non-corresponding portion 412 to be formed at a portion of the corresponding portion 411.

[0080] The second gap G52 may be formed between the expanded slit 521 at both ends of the slit 503 provided in the slot die 520 and the corresponding portion 411 adjacent to the non-corresponding portion 412 of the roller 410. The second gap G52 may form the coating edge portion C2 by increasing the coating amount of the active material slurry at both ends of the corresponding portion 411 adjacent to the non-corresponding portion 412 compared to the coating amount of the active material slurry in the coating center portion C1.

[0081] As an example, the expansion slit 521 may have an inclined portion 522 formed as a convex curved surface that gently inclines away from the roller 410 and then steeply inclines, and a plane portion 523 connected to the inclined portion 522 (e.g., extending from the inclined portion 522) in the axial direction of the roller 410. The inclined portion 522 in the expansion slit 521 may gradually increase the first gap G41 to the second gap G52 to prevent a sharp increase in the coating amount in the plane portion 523. Accordingly, the inclined portion 522 connecting the slit 503 and the plane portion 523 may provide a gradual increase in the coating amount in each of the coating center portion C1 and the coating edge portion C2.

[0082] Due to the first and second gaps G41 and G52 formed by the inclined portion 522 and the planar portion 523 of the expansion slit 521 , the coating amount of the active material slurry in the coating edge portion C2 may be increased compared to the coating center portion C1 .

[0083] The coating of the central portion C1 and the coating of the edge portion C2 can form the same level of coating amount and the same coating height (H) (see, for example Figure 2 ). For example, the coating amount and coating height (H) of the active material slurry may be uniform or substantially uniform in a region where the positive electrode E1 and the negative electrode E2 face each other.

[0084] Therefore, when the electrode substrate S5 is used in the electrode assembly of the rechargeable battery, the face-to-face distance and face-to-face capacity between the positive electrode and the negative electrode in the rechargeable battery can be constantly ensured. Accordingly, the resistance can be reduced at the portion where the negative electrode and the positive electrode face each other, and safety can be ensured.

[0085] Figure 7 2 is a state diagram illustrating a first gap and a second gap between a roller and a slit die in a coating apparatus for an electrode substrate of a rechargeable battery according to another embodiment of the present disclosure. Figure 7 , in the coating apparatus 6 according to this embodiment, the roller 410 may have a corresponding portion 411 corresponding to the slot die 620 and a non-corresponding portion 412 formed longer than the slot die 620 so as not to correspond to the slot die 620 .

[0086] In the corresponding portion 411, the slit die 620 and the roller 410 may form a first gap G41 between each other. For example, in the corresponding portion 411, the slit 603 in the slit die 620 and the electrode substrate S6 may form a first gap G41 between each other. The first gap G41 may be formed by making the coating amount of the active material slurry constant or substantially constant in the corresponding portion 411. Figure 2 The coated center portion C1 is shown in FIG.

[0087] Both ends of the slit 603 in the slot die 620 may have an expanded slit 621 corresponding to a portion of the roller 410 adjacent to the non-corresponding portion 412. The expanded slit 621 may start from a connection portion between the corresponding portion 411 and the non-corresponding portion 412 to be formed at a portion of the corresponding portion 411.

[0088] The second gap G62 may be formed between the expanded slit 621 at both ends of the slit 603 provided in the slot die 620 and the corresponding portion 411 adjacent to the non-corresponding portion 412 of the roller 410. The second gap G62 may form the coating edge portion C2 by increasing the coating amount of the active material slurry at both ends of the corresponding portion 411 adjacent to the non-corresponding portion 412 compared to the coating amount of the active material slurry in the coating center portion C1.

[0089] As an example, the expansion slit 621 may have an inclined portion 622 formed as a concave curved surface that is steeply inclined away from the roller 410 and then gently inclined, and a plane portion 623 connected to the inclined portion 622 (e.g., extending from the inclined portion 622) in the axial direction of the roller 410. The inclined portion 622 in the expansion slit 621 may gradually increase the first gap G41 to the second gap G62 to prevent a sharp increase in the coating amount in the plane portion 623. Accordingly, the inclined portion 622 connecting the slit 603 and the plane portion 623 may provide a gradual increase in the coating amount in each of the coating center portion C1 and the coating edge portion C2.

[0090] Due to the first and second gaps G41 and G62 formed by the inclined portion 622 and the planar portion 623 of the expanded slit 621 , the coating amount of the active material slurry in the coating edge portion C2 may be increased compared to the coating amount of the active material slurry in the coating center portion C1 .

[0091] The coating of the central portion C1 and the coating of the edge portion C2 can form the same level of coating amount and the same coating height (H) (see, for example Figure 2 ). For example, the coating amount and coating height (H) of the active material slurry may be uniform or substantially uniform in a region where the positive electrode E1 and the negative electrode E2 face each other.

[0092] Therefore, when the electrode substrate S6 is used in the electrode assembly of the rechargeable battery, the face-to-face distance and face-to-face capacity between the positive electrode and the negative electrode in the rechargeable battery can be constantly ensured. Accordingly, the resistance can be reduced at the portion where the negative electrode and the positive electrode face each other, and safety can be ensured.

[0093] While the disclosure has been described in connection with what are presently considered to be practical embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0094] Description of some reference numerals:

[0095] 1, 2, 3, 4, 5, 6: coating device 10, 210, 310, 410: roller

[0096] 11, 211: corresponding part

[0097] 12, 212: Non-corresponding parts

[0098] 20: Slit die 21: First piece

[0099] 22: The second piece 23: The rift

[0100] 121, 221, 321: Small diameter part

[0101] 122, 222, 322: frustoconical surface

[0102] 123, 223, 323: cylindrical surface 201: chamber

[0103] 403, 503, 603: slit 410: roller

[0104] 411: corresponding part 412: non-corresponding part

[0105] 420: Slit die 421: Expanded slit

[0106] 422: inclined part 423: flat part

[0107] 520: Slit die 521: Expanded slit

[0108] 522: inclined part 523: flat part

[0109] 620: Slit die 621: Expanded slit

[0110] 622: inclined part 623: flat part

[0111] C1: Coating the center part C2: Coating the edge part

[0112] CP, CP2, CP3: coated part CP4: coated part

[0113] CP5: Coating part CP6: Coating part

[0114] G1: First gap G2, G22, G32: Second gap

[0115] G41: First gap G42: Second gap

[0116] G52: Second gap G62: Second gap

[0117] H: coating height S, S2, S3, S4, S5, S6: electrode substrate

[0118] UCP: Uncoated part W: Coated width

Claims

1. A coating device for an electrode substrate of a rechargeable battery, comprising: a roller configured to continuously supply an electrode substrate; as well as a slit die configured to form an active material coating portion on the electrode substrate, The roller and the slot die form a first gap between each other at the center in the width direction of the electrode substrate and form a second gap larger than the first gap between each other at both ends in the width direction of the electrode substrate. 2 . The coating apparatus according to claim 1 , wherein the first gap is between a slit in the slot die and the electrode substrate on the roller.

3. The coating apparatus according to claim 2, wherein the roller has a non-corresponding portion extending beyond the slot die, and wherein the non-corresponding portion corresponding to an end portion of the slit in the slot die has a small diameter portion. 4 . The coating apparatus according to claim 3 , wherein the second gap is formed between the end portion of the slit in the slot die and the small diameter portion of the roller.

5. The coating device according to claim 3, wherein the small diameter portion has: a frustoconical surface, tapering away from said end portion of said slit of said slot die; and A cylindrical surface extends from the frustoconical surface in the axial direction of the roller.

6. The coating device according to claim 3, wherein the small diameter portion has: a frustoconical surface formed as a convex curved surface which slopes gently and then steeply at the end portion away from the slit in the slot die; and A cylindrical surface extends from the frustoconical surface in the axial direction of the roller.

7. The coating device according to claim 3, wherein the small diameter portion has: a frustoconical surface formed as a concave curved surface that slopes sharply and then gently away from the end portion of the slit in the slot die; and A cylindrical surface extends from the frustoconical surface in the axial direction of the roller.

8. The coating apparatus of claim 2, wherein the roller has a non-corresponding portion extending beyond the slot die, and wherein both ends of the slit in the slot die have expanded slits corresponding to portions of the roller adjacent to the non-corresponding portions. 9 . The coating apparatus according to claim 8 , wherein the second gap is formed between the expanded slits at the both ends of the slit in the slot die and the portion of the roller adjacent to the non-corresponding portion.

10. The coating device according to claim 8, wherein the expansion slit has: an inclined portion inclined away from the roller; and A planar portion extends from the inclined portion in the axial direction of the roller.

11. The coating device according to claim 8, wherein the expansion slit has: an inclined portion formed as a convexly curved surface that gently inclines away from the roller and then steeply inclines; and A planar portion extends from the inclined portion in the axial direction of the roller.

12. The coating device according to claim 8, wherein the expansion slit has: an inclined portion formed as a concave curved surface that is steeply inclined away from the roller and then gently inclined; and A planar portion extends from the inclined portion in the axial direction of the roller.

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