Coating device for secondary battery electrode base material

Abstract

To provide a coating device for a secondary battery electrode base material, capable of controlling a shape and an active material coating amount of a coating edge part, and miniaturizing a difference of the active material coating amount between a coating center part and an edge part, or capable of controlling the shape and the active material coating amount of the coating edge part, realizing a facing plane ratio of a positive electrode and a negative electrode so as to be safe, and constantly maintaining a facing plane distance.SOLUTION: The present invention provides a coating device for a secondary battery electrode base material. The coating device for the secondary battery electrode base material contains: a roll that continuously supplies an electrode base material; and a slot die that forms an active material coating part to the electrode base material. The roll and the slot die form a first gap between width direction centers of the electrode base material, and forms a second gap larger than the first gap in both ends of the width direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a coating apparatus for a secondary battery electrode substrate, which coats an electrode substrate of a secondary battery with an active material slurry. [Background technology]

[0002] A rechargeable battery is a battery that can be repeatedly charged and discharged, unlike a primary battery. Small-capacity secondary batteries are used in small, portable electronic devices such as mobile phones, laptops, and camcorders, while large-capacity secondary batteries can be used as power sources for driving the motors of hybrid and electric vehicles.

[0003] For example, a secondary battery includes an electrode assembly that charges and discharges, packaging (e.g., a pouch or can) that contains the electrode assembly, and an electrode terminal that electrically connects the electrode assembly and extends to the outside of the pouch. The electrode assembly includes a winding type in which negative and positive electrode plates are wound on both sides with a separator between them, and a stacking type in which negative and positive electrode plates are stacked on both sides with a separator between them.

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

[0005] The positive and negative electrodes thus manufactured face each other when in operation. The ratio of positive and negative electrodes in a secondary battery is very important to ensure safety. The capacity of the negative electrode must always be greater than that of the positive electrode. In other words, if there is enough room for lithium ions to be inserted into the negative electrode active material, it can operate without side reactions occurring.

[0006] However, when using a typical slot die coating method, the amount of coating is reduced at the edges. Insufficient coating amount increases the distance between the positive and negative electrodes, which increases resistance and can reduce safety due to the inversion phenomenon caused by an imbalance in the capacitance between the electrodes. In other words, it is necessary to have a shape that maintains the distance between the electrodes and a uniform amount of active material across the entire area.

[0007] To overcome this, the flow rate was controlled by controlling rheology and changing the shape of the spacer inside the slot die, but there was still a difference in the sliding shape of the coating edge and the amount of active material. Summary of the Invention [Problem to be solved by the invention]

[0008] One embodiment of the present invention provides a coating apparatus for a secondary battery electrode substrate that controls the shape of the coating edge and the amount of active material applied to minimize the difference in the amount of active material applied between the center and edge of the coating.

[0009] One embodiment of the present invention provides a coating device for a secondary battery electrode substrate that controls the shape of the coating edge portion and the amount of active material applied, ensures a safe facing ratio between the positive and negative electrodes, and maintains a constant facing distance. [Means for solving the problem]

[0010] A coating apparatus for an electrode substrate for a secondary battery according to one embodiment of the present invention includes a roll for continuously supplying an electrode substrate, and a slot die for forming an active material coating portion on the electrode substrate, the roll and the slot die forming a first gap between each other in a widthwise center of the electrode substrate, and forming second gaps larger than the first gap at both widthwise ends.

[0011] The first gap may be set between a lip of the slot die and the electrode substrate advancing onto the roll.

[0012] The roll may have a non-corresponding portion that is longer than the slot die, and may have small diameter portions at the non-corresponding portion that corresponds to both ends of the slot die lip.

[0013] The second gap may be set between an end of the slot die lip and the small diameter portion of the roll.

[0014] The small diameter portion may include a truncated cone surface that is inclined away from the end of the slot die lip, and a cylindrical surface that is connected to the truncated cone surface and is connected in the axial direction of the roll.

[0015] The small diameter portion may include a truncated cone surface formed of a convex curved surface that gradually slopes away from the end of the slot die lip and then steeply slopes, and a cylindrical surface connected to the truncated cone surface and connected in the axial direction of the roll.

[0016] The small diameter portion may include a truncated cone surface formed of a concave curved surface that is steeply inclined and then gently inclined as it moves away from the end of the slot die lip, and a cylindrical surface connected to the truncated cone surface and connected in the axial direction of the roll.

[0017] The roll may have a non-compliant portion longer than the slot die, and both ends of the slot die lip may have extended lips that mate with the roll adjacent the non-compliant portion.

[0018] The second gap can be set between the extension lips provided on both ends of the slot die lip and the roll adjacent to the non-corresponding portion.

[0019] The extended lip may include an inclined portion that is inclined as it moves away from the roll, and a flat portion that is connected to the inclined portion and is connected in the axial direction of the roll.

[0020] The extension lip may include an inclined portion formed of a convex curved surface that gradually inclines and then steeply inclines as it moves away from the roll, and a flat portion connected to the inclined portion and connected in the axial direction of the roll.

[0021] The extension lip may include an inclined portion formed of a concave curved surface that is steeply inclined and then gradually inclined as it moves away from the roll, and a flat portion connected to the inclined portion and connected in the axial direction of the roll. Effect of the Invention

[0022] In one embodiment, the gap between the roll and the slot die is formed as a first gap in the center of the width of the electrode substrate, and a second gap larger than the first gap is formed at both ends of the width, so that the shape of the coating edge and the amount of active material applied can be controlled. Therefore, in one embodiment, the difference in the amount of active material applied between the center and edges of the coating can be minimized.

[0023] In one embodiment, the widthwise center of the electrode substrate is formed as a first gap, and both widthwise ends are formed as second gaps larger than the first gap, thereby controlling the shape of the coating edge portion and the amount of active material applied, thereby making it possible to make the facing ratio of the positive electrode and the negative electrode safe and maintain a constant facing distance. [Brief description of the drawings]

[0024] [Figure 1] 1 is a cross-sectional view of a coating apparatus for a secondary battery electrode substrate according to a first embodiment of the present invention. [Diagram 2] 2A to 2C are a plan view of a slot die applying active material to an electrode substrate supplied by the roll in FIG. 1, a cross-sectional view of the shape of the applied active material coating portion, and a cross-sectional view of the opposing portions of a negative electrode and a positive electrode. [Diagram 3] FIG. 11 is a state diagram showing a state in which a first gap and a second gap are formed between a roll and a slot die in a coating apparatus for a secondary battery electrode substrate according to a second embodiment of the present invention. [Figure 4] FIG. 11 is a state diagram showing a state in which a first gap and a second gap are formed between a roll and a slot die in a coating apparatus for a secondary battery electrode substrate according to a third embodiment of the present invention. [Diagram 5] FIG. 13 is a plan view showing a coating apparatus for a secondary battery electrode substrate according to a fourth embodiment of the present invention, in which an active material is applied to an electrode substrate supplied by a roll using a slot die. [Figure 6] FIG. 13 is a diagram showing a state in which a first gap and a second gap are formed between a roll and a slot die in a coating apparatus for a secondary battery electrode substrate according to a fifth embodiment of the present invention. [Figure 7] FIG. 13 is a state diagram showing a state in which a first gap and a second gap are formed between a roll and a slot die in a coating apparatus for a secondary battery electrode substrate according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention can be embodied in various different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not necessary for the explanation are omitted, and the same reference numerals are used throughout the specification to refer to the same or similar components.

[0026] FIG. 1 is a cross-sectional view of a coating apparatus for a secondary battery electrode substrate according to a first embodiment of the present invention, and FIG. 2 is a plan view (a) of a slot die coating an active material onto an electrode substrate supplied by a roll in FIG. 1, a cross-sectional view (b) of the shape of the coated active material coating, and cross-sectional views (c, d) of opposing portions of a negative electrode and a positive electrode.

[0027] 1 and 2, a coating apparatus 1 for a secondary battery electrode substrate of the first embodiment includes a roll 10 that continuously supplies an electrode substrate (S), and a slot die 20 that forms an active material coating portion (CP) on the electrode substrate (S). The roll 10 is driven to rotate and advances the electrode substrate (S) toward the slot die 20 to coat the electrode substrate (S) with an active material, and then advances the electrode substrate (S) away from the slot die 20.

[0028] As an example, the slot die 20 includes a first block 21, a second block 22, and a shim member (not shown) provided therebetween. The first and second blocks 21 and 22 and the shim member provided therebetween can be fastened with a fastening member (not shown) to form a slot die for coating the active material slurry.

[0029] The first block 21 has a chamber 201 formed to temporarily store the supplied active material slurry and supply it uniformly across the entire width. A supply unit is connected to the lower part of the first block 21 to supply the active material slurry to the chamber 201. The first and second blocks 21 and 22 coupled to each other form a rip 23 for discharging the active material slurry.

[0030] The slot die 20 temporarily stores the active material slurry supplied through the supply unit in the chamber 201 and discharges it through the lip 23, so that the active material slurry is applied in a uniform amount in the width direction to the electrode substrate (S) proceeding in front of the lip 23. Therefore, the electrode substrate (S) is formed with a coated portion (CP) where the active material slurry is applied, and uncoated portions (UCP) on both sides of the coated portion (CP) where the active material slurry is not applied and the electrode substrate (S) is exposed.

[0031] The coating part (CP) forms a coating center part (C1) in the center of the width direction of the electrode substrate (S) and forms coating edge parts (C2) on both sides of the coating center part (C1) in the width direction.

[0032] In the first embodiment, the shape of the coating edge portion (C2) and the amount of coating applied to the coating edge portion (C2) are controlled to reduce the difference in the amount of coating applied to the coating center portion (C1) and the coating edge portion (C2), thereby making the facing distance between the facing positive and negative electrodes uniform and ensuring the stability of the battery.

[0033] For this purpose, the roll 10 and the slot die 20 form a first gap (G1) between them from the center of the width direction (x-axis direction) of the electrode substrate (S) in the advancing direction of the electrode substrate (S), and form a second gap (G2) larger than the first gap (G1) at both ends in the width direction. In effect, the first gap (G1) and the second gap (G2) are set between the lip 23 of the slot die 20 and the electrode substrate (S) advanced on the roll 10.

[0034] The first and second gaps (G1, G2) are provided to ensure that the amount of active material applied is constant when the positive and negative active material slurries are respectively coated onto each electrode substrate (S). That is, the first gap (G1) relatively keeps the amount and height (H) of the coating constant at the coating center (C1), and the second gap (G2) makes the amount of the coating at the coating edge (C2) the same as that at the coating center (C1).

[0035] Therefore, the coating amount and coating height (H) of the active material slurry in the area where the positive electrode (E1) and the negative electrode (E2) face each other are uniform. That is, in the first embodiment, the coating amount and coating height (H) of the active material slurry in the area where the positive electrode (E1) and the negative electrode (E2) face each other are more uniform (d) than the coating amount and coating height (H) of the active material slurry in the area where the positive electrode (E11) and the negative electrode (E21) face each other in the conventional technology (c), so that the stability of the battery can be ensured.

[0036] More specifically, referring to FIG. 2, the roll 10 has a corresponding portion 11 that corresponds to the slot die 20 and a non-corresponding portion 12 that is longer than the slot die 20 and does not correspond to the slot die 20.

[0037] In the corresponding portion 11, the slot die 20 and the roll 10 form a first gap (G1) between them. More precisely, in the corresponding portion 11, the lip 23 of the slot die 20 and the electrode substrate (S) form a first gap (G1) between them. The first gap (G1) keeps the amount of active material slurry applied in the corresponding portion 11 constant and forms a coating center portion (C1).

[0038] The non-corresponding portion 12 of the roll 10 is provided with a small diameter portion 121 having a diameter smaller than that of the corresponding portion 11. The small diameter portion 121 is formed in the non-corresponding portion 12 corresponding to both ends of the lip 23 of the slot die 20. That is, the small diameter portion 121 starts from the connecting portion between the corresponding portion 11 and the non-corresponding portion 12 and is formed throughout the non-corresponding portion 12.

[0039] As an example, the reduced diameter portion 121 includes a frusto-conical surface 122 that is inclined as it moves away from the end of the lip 23 of the slot die 20, and a cylindrical surface 123 that is connected to the frusto-conical surface 122 and is connected in the axial direction of the roll 10.

[0040] In the non-corresponding portion 12, the slot die 20 and the roll 10 form a second gap (G2) between them. More precisely, in the small diameter portion 121 of the non-corresponding portion 12, the lip 23 of the slot die 20 and the electrode substrate (S) form a second gap (G2) between them. The second gap (G2) increases the amount of active material slurry applied in the non-corresponding portion 12 compared to the coating center portion (C1) to form a coating edge portion (C2).

[0041] The truncated cone surface 122 at the small diameter portion 121 allows the first gap (G1) to increase gradually to the second gap (G2) and prevents a sudden increase in the coating amount at the cylindrical surface 123. Thus, the truncated cone surface 122 connecting the corresponding portion 11 and the cylindrical surface 123 allows a gradual increase in the coating amount at the coating center (C1) and the coating edge (C2).

[0042] In this manner, the first and second gaps (G1, G2) formed by the small diameter portion 121, i.e., the truncated cone surface 122 and the cylindrical surface 123, allow the amount of active material slurry applied to be greater at the coating edge portion (C2) than at the coating center portion (C1).

[0043] The coating center (C1) and coating edge (C2) form the same coating amount and coating height (H), i.e., the coating amount and coating height (H) of the active material slurry become uniform in the region where the positive electrode (E1) and the negative electrode (E2) face each other.

[0044] Therefore, when the electrode substrate (S) of the first embodiment is applied, the facing distance and the facing capacity of the positive and negative electrodes in the secondary battery are kept constant, which reduces the resistance at the facing portion between the positive and negative electrodes and ensures safety.

[0045] Various embodiments of the present invention will be described below. Descriptions of configurations that are the same as those in the first embodiment and the embodiments already described will be omitted, and only configurations that are different from those in the first embodiment will be described.

[0046] 3 is a diagram showing a state where a first gap and a second gap are formed between a roll and a slot die in a coating apparatus for a secondary battery electrode substrate according to a second embodiment of the present invention. Referring to FIG. 3, in the coating apparatus 2 of the second embodiment, the small diameter portion 221 includes a convex frustum surface 222 that is gradually inclined and then steeply inclined as it moves away from the end of the lip 23 of the slot die 20, and a cylindrical surface 223 that is connected to the frustum surface 222 and is connected in the axial direction of the roll 210.

[0047] In the non-corresponding portion 212, the slot die 20 and the roll 210 form a second gap (G22) between them. More precisely, in the small diameter portion 221 of the non-corresponding portion 212, the lip 23 of the slot die 20 and the electrode substrate (S2) form a second gap (G22) between them. The second gap (G22) increases the amount of active material slurry applied in the non-corresponding portion 212 compared to the coating center portion (C1, see FIG. 2) to form a coating edge portion (C2, see FIG. 2).

[0048] The truncated cone surface 222 at the small diameter portion 221 prevents a sudden increase in the coating amount at the cylindrical surface 223 by gradually increasing the first gap (G1) to the second gap (G22) and then suddenly increasing it. Thus, the truncated cone surface 222 connecting the corresponding portion 211 and the cylindrical surface 223 allows a gradual increase in the coating amount at the coating center (C1) and the coating edge (C2).

[0049] In this manner, the first and second gaps (G1, G22) between the small diameter portion 221, i.e., the truncated cone surface 222 and the cylindrical surface 223, allow the amount of active material slurry applied to be greater at the coating edge portion (C2) than at the coating center portion (C1).

[0050] The coating center (C1) and coating edge (C2) form the same coating amount and coating height (H), i.e., the coating amount and coating height (H) of the active material slurry become uniform in the region where the positive electrode (E1) and the negative electrode (E2) face each other.

[0051] Therefore, when the electrode substrate (S2) of the second embodiment is applied, the facing distance and the facing capacity of the positive and negative electrodes in the secondary battery are kept constant, which reduces the resistance at the facing portion between the positive and negative electrodes and ensures safety.

[0052] 4 is a diagram showing a state where a first gap and a second gap are formed in a roll and a slot die in a coating apparatus for a secondary battery electrode substrate according to a third embodiment of the present invention. Referring to FIG. 4, in the coating apparatus 3 of the third embodiment, the small diameter portion 321 includes a concavely curved truncated cone surface 322 that steeply inclines and then gradually inclines as it moves away from the end of the lip 23 of the slot die 20, and a cylindrical surface 323 that is connected to the truncated cone surface 322 and is connected in the axial direction of the roll 310.

[0053] In the non-corresponding portion 312, the slot die 20 and the roll 310 form a second gap (G32) between them. More precisely, in the small diameter portion 321 of the non-corresponding portion 312, the lip 23 of the slot die 20 and the electrode substrate (S3) form a second gap (G32) between them. The second gap (G32) increases the amount of active material slurry applied in the non-corresponding portion 312 compared to the coating center portion (C1, see FIG. 2) to form a coating edge portion (C2, see FIG. 2).

[0054] The truncated cone surface 322 in the small diameter portion 321 prevents a sudden increase in the coating amount at the cylindrical surface 323 by gradually increasing the gap after the first gap (G1) suddenly increases to the second gap (G32). Thus, the truncated cone surface 322 connecting the corresponding portion 311 and the cylindrical surface 323 allows a gradual increase in the coating amount at the coating center (C1) and the coating edge (C2).

[0055] In this manner, the first and second gaps (G1, G32) formed by the small diameter portion 321, i.e., the truncated cone surface 322 and the cylindrical surface 323, allow the amount of active material slurry applied to be greater at the coating edge portion (C2) than at the coating center portion (C1).

[0056] The coating center (C1) and coating edge (C2) form the same coating amount and coating height (H), i.e., the coating amount and coating height (H) of the active material slurry become uniform in the region where the positive electrode (E1) and the negative electrode (E2) face each other.

[0057] Therefore, when the electrode substrate (S3) of the third embodiment is applied, the facing distance and the facing capacity of the positive and negative electrodes in the secondary battery are kept constant, which reduces the resistance at the facing portion between the positive and negative electrodes and ensures safety.

[0058] 5 is a plan view of a coating apparatus for a secondary battery electrode substrate according to a fourth embodiment of the present invention, in which an active material is applied to an electrode substrate supplied by a roll through a slot die. Referring to FIG. 5, in the coating apparatus 4 of the fourth embodiment, a roll 410 includes a corresponding portion 411 corresponding to the slot die 420 and a non-corresponding portion 412 that is longer than the slot die 420 and does not correspond to the slot die 420.

[0059] In the corresponding portion 411, the slot die 420 and the roll 410 form a first gap (G41) between them. More precisely, in the corresponding portion 411, the lip 403 of the slot die 420 and the electrode substrate (S4) form a first gap (G41) between them. The first gap (G41) keeps the amount of active material slurry applied constant in the corresponding portion 411 to form a coating center portion (C1, see FIG. 2).

[0060] Both ends of the lip 403 of the slot die 420 include an extended lip 421 that corresponds to the roll 410 adjacent to the non-matching portion 412. The extended lip 421 starts at the junction of the corresponding portion 411 and the non-matching portion 412 and is formed into a part of the corresponding portion 411.

[0061] A second gap (G42) is set between extended lips 421 provided at both ends of the lip 403 of the slot die 420 and the corresponding portion 411 of the roll 410 adjacent to the non-corresponding portion 412. The second gap (G42) increases the amount of active material slurry applied at both ends of the corresponding portion 411 adjacent to the non-corresponding portion 412 compared to the coating center portion (C1), thereby forming coating edge portions (C2).

[0062] As an example, the extended lip 421 includes an inclined portion 422 that is inclined as it moves away from the roll 410, and a flat portion 423 that is connected to the inclined portion 422 and connected in the axial direction of the roll 410. In the extended lip 421, the inclined portion 422 prevents a sudden increase in the coating amount at the flat portion 423 by gradually increasing the first gap (G41) to the second gap (G42). Thus, the inclined portion 422 connecting the corresponding portion 411 and the flat portion 423 allows a gradual increase in the coating amount at the coating center portion (C1) and the coating edge portion (C2).

[0063] In this manner, the extended lip 421, i.e., the first and second gaps (G41, G42) formed by the inclined portion 422 and the flat portion 423, allows the amount of active material slurry applied to be increased at the coating edge portion (C2) compared to the coating center portion (C1).

[0064] The coating center (C1) and coating edge (C2) have the same coating amount and coating height (H) (see FIG. 2). In other words, the coating amount and coating height (H) of the active material slurry become uniform in the area where the positive electrode (E1) and negative electrode (E2) face each other.

[0065] Therefore, when the electrode substrate (S4) of the fourth embodiment is applied, the facing distance and the facing capacity of the positive and negative electrodes in the secondary battery are kept constant, which reduces the resistance at the facing portion between the positive and negative electrodes and ensures safety.

[0066] 6 is a diagram showing a state where a first gap and a second gap are formed between a roll and a slot die in a coating apparatus for a secondary battery electrode substrate according to a fifth embodiment of the present invention. Referring to FIG. 6, in the coating apparatus 5 of the fifth embodiment, a roll 410 has a corresponding portion 411 corresponding to the slot die 520 and a non-corresponding portion 412 that is formed longer than the slot die 520 and does not correspond to the slot die 520.

[0067] In the corresponding portion 411, the slot die 520 and the roll 410 form a first gap (G41) between them. More precisely, in the corresponding portion 411, the lip 503 of the slot die 520 and the electrode substrate (S5) form a first gap (G41) between them. The first gap (G41) keeps the amount of active material slurry applied constant in the corresponding portion 411 to form a coating center portion (C1, see FIG. 2).

[0068] Both ends of the lip 503 of the slot die 520 include an extended lip 521 that corresponds to the roll 410 adjacent to the non-corresponding portion 412. The extended lip 521 starts at the junction of the corresponding portion 411 and the non-corresponding portion 412 and is formed into a part of the corresponding portion 411.

[0069] The second gap (G52) can be set between the extended lips 521 provided on both ends of the lip 503 of the slot die 520 and the corresponding portion 411 of the roll 410 adjacent to the non-corresponding portion 412. The second gap (G52) increases the amount of active material slurry applied at both ends of the corresponding portion 411 adjacent to the non-corresponding portion 412 compared to the coating center portion (C1), thereby forming coating edge portions (C2).

[0070] As an example, the extended lip 521 includes an inclined portion 522 formed of a convex curved surface that gradually inclines and then steeply inclines as it moves away from the roll 410, and a flat portion 523 connected to the inclined portion 522 and connected in the axial direction of the roll 410. In the extended lip 521, the inclined portion 522 allows the first gap (G41) to gradually increase to the second gap (G52) and prevents a sudden increase in the coating amount at the flat portion 523. Thus, the inclined portion 522 connecting the corresponding portion 411 and the flat portion 523 allows a gradual increase in the coating amount at the coating center portion (C1) and the coating edge portion (C2).

[0071] In this manner, the extended lip 521, ie, the first and second gaps (G41, G52) formed by the inclined portion 522 and the flat portion 523, allows the amount of active material slurry applied to be increased at the coating edge portion (C2) compared to the coating center portion (C1).

[0072] The coating center (C1) and coating edge (C2) have the same coating amount and coating height (H) (see FIG. 2). In other words, the coating amount and coating height (H) of the active material slurry become uniform in the area where the positive electrode (E1) and negative electrode (E2) face each other.

[0073] Therefore, when the electrode substrate (S5) of the fifth embodiment is applied, the facing distance and the facing capacity of the positive and negative electrodes in the secondary battery are kept constant, which reduces the resistance at the facing portion between the positive and negative electrodes and ensures safety.

[0074] 7 is a state diagram showing a state where a first gap and a second gap are formed between a roll and a slot die in a coating apparatus for a secondary battery electrode substrate according to a sixth embodiment of the present invention. Referring to FIG. 7, in the coating apparatus 6 of the sixth embodiment, a roll 410 has a corresponding portion 411 corresponding to the slot die 620 and a non-corresponding portion 412 that is formed longer than the slot die 620 and does not correspond to the slot die 620.

[0075] In the corresponding portion 411, the slot die 620 and the roll 410 form a first gap (G41) between them. More precisely, in the corresponding portion 411, the lip 603 of the slot die 620 and the electrode substrate (S6) form a first gap (G41) between them. The first gap (G41) keeps the amount of active material slurry applied constant in the corresponding portion 411 to form a coating center portion (C1, see FIG. 2).

[0076] Both ends of the lip 603 of the slot die 620 include an extended lip 621 that corresponds to the roll 410 adjacent to the non-matching portion 412. The extended lip 621 starts at the junction of the corresponding portion 411 and the non-matching portion 412 and is formed into a part of the corresponding portion 411.

[0077] The second gap (G62) can be set between the extended lips 621 provided at both ends of the lip 603 of the slot die 620 and the corresponding portion 411 of the roll 410 adjacent to the non-corresponding portion 412. The second gap (G62) increases the amount of active material slurry applied at both ends of the corresponding portion 411 adjacent to the non-corresponding portion 412 compared to the coating center portion (C1), thereby forming coating edge portions (C2).

[0078] As an example, the extended lip 621 includes an inclined portion 622 formed of a convex curved surface that gradually inclines and then steeply inclines as it moves away from the roll 410, and a flat portion 623 connected to the inclined portion 622 and connected in the axial direction of the roll 410. In the extended lip 621, the inclined portion 622 allows the first gap (G41) to gradually increase to the second gap (G62) and prevents a sudden increase in the coating amount at the flat portion 623. Thus, the inclined portion 622 connecting the corresponding portion 411 and the flat portion 623 allows a gradual increase in the coating amount at the coating center portion (C1) and the coating edge portion (C2).

[0079] In this manner, the extended lip 621, ie, the first and second gaps (G41, G62) formed by the inclined portion 622 and the flat portion 623, allows the amount of active material slurry applied to be greater at the coating edge portion (C2) than at the coating center portion (C1).

[0080] The coating center (C1) and coating edge (C2) have the same coating amount and coating height (H) (see FIG. 2). In other words, the coating amount and coating height (H) of the active material slurry become uniform in the area where the positive electrode (E1) and negative electrode (E2) face each other.

[0081] Therefore, when the electrode substrate (S6) of the sixth embodiment is applied, the facing distance and the facing capacity of the positive and negative electrodes in the secondary battery are kept constant, which reduces the resistance of the facing portions of the positive and negative electrodes and ensures safety.

[0082] Although the preferred embodiment of the present invention has been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the description of the invention, and the accompanying drawings, which of course also fall within the scope of the present invention. [Explanation of symbols]

[0083] 1, 2, 3, 4, 5, 6 Coating equipment 10, 210, 310, 410 rolls 11, 211 Response Department 12, 212 Non-compliant parts 20 Slot Die 21 1st Block 22 2nd Block 23 Lip 121, 221, 321 Small diameter section 122, 222, 322 truncated cone surface 123, 223, 323 Cylinder surface 201 Chamber 403, 503, 603 Lip 410 rolls 411 Response Department 412 Non-compliant section 420 Slot Die 421 Extended Lip 422 Slope 423 Plane section 520 Slot Die 521 Extended Lip 522 Slope 523 Plane part 620 Slot Die 621 Extended Lip 622 Slope 623 Plane part C1 Coating center C2 Coating edge part CP, CP2, CP3 Coating Parts CP4 Coating Division CP5 Coating Section CP6 Coating Department G1 First Gap G2, G22, G32 Second Gap G41 First Gap G42 2nd Gap G52 Second Gap G62 Second Gap H Coating height S, S2, S3, S4, S5, S6 electrode base material UCP plain area W Coating width

Claims

1. A roll for continuously supplying an electrode substrate; and a slot die for forming an active material coating on the electrode substrate; The roll and the slot die are A first gap is formed between the electrode substrates at a center in a width direction of the electrode substrates, a slot die coating apparatus forming a second gap larger than the first gap at both ends in the width direction.

2. The first gap is The slot die coating apparatus according to claim 1 , wherein the slot die coating apparatus is set between a lip of the slot die and the electrode substrate advanced onto the roll.

3. The roll is A non-compliant portion is provided that is longer than the slot die; The slot die coating apparatus according to claim 2 , wherein the non-corresponding portions of the slot die lip corresponding to both ends of the slot die lip have small diameter portions.

4. The second gap is The slot die coating apparatus of claim 3 , wherein the slot die is positioned between an end of the slot die lip and the small diameter portion of the roll.

5. The small diameter portion is a frusto-conical surface that slopes away from the end of the slot die lip; and 4. The slot die coating apparatus of claim 3, further comprising a cylindrical surface connected to said frustoconical surface and axially connected to said roll.

6. The small diameter portion is A truncated cone surface that is gradually inclined away from the end of the slot die lip and then is formed by a convex curve that is steeply inclined; and 4. The slot die coating apparatus of claim 3, further comprising a cylindrical surface connected to said frustoconical surface and axially connected to said roll.

7. The small diameter portion is a truncated cone surface formed by a concave curved surface that slopes steeply away from the end of the slot die lip and then slopes gently; and 4. The slot die coating apparatus of claim 3, further comprising a cylindrical surface connected to said frustoconical surface and axially connected to said roll.

8. The roll is A non-compliant portion is provided that is longer than the slot die; Both ends of the slot die lip are The slot die coating apparatus of claim 2 , further comprising an extended lip that corresponds to the roll adjacent the non-compliant portion.

9. The second gap is The slot die coating apparatus according to claim 8, wherein the slot die coating apparatus is set between the extended lips provided at both ends of the slot die lip and the roll adjacent to the non-corresponding portion.

10. The extension lip is An inclined portion formed so as to be inclined as it moves away from the roll; and 9. The slot die coating apparatus of claim 8, further comprising a planar portion connected to the inclined portion and axially connected to the roll.

11. The extension lip is An inclined portion formed of a convex curved surface that gradually inclines and then steeply inclines as it moves away from the roll; and 9. The slot die coating apparatus of claim 8, further comprising a planar portion connected to the inclined portion and axially connected to the roll.

12. The extension lip is A sloped portion formed of a concave curved surface that slopes steeply as it moves away from the roll and then slopes gently; and 9. The slot die coating apparatus of claim 8, further comprising a planar portion connected to the inclined portion and axially connected to the roll.

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