Device for coating a metallic substrate and its process

Abstract

Device (1) for coating a metallic substrate (2) for manufacturing electrodes for electric battery cells for electric vehicles, comprising: - a first rolling roll (3) rotating in a first direction (5) of rotation, - a second rolling roll (4) rotating in a second direction (6) of rotation opposite to the first direction (5) of rotation, the first roll (3) and the second roll (4) being arranged opposite each other and spaced apart so as to define a passage for the metallic substrate (2), - at least one first device (8) for supplying at least one solvent-free active material (9) to the first roll (3), and - at least one first means (13) for controlling the thickness of the active material (9) on the first roll (3). Figure for the abstract: Figure 1

Description

Title of the invention: Device for coating a metallic substrate and its method Technical field of the invention

[0001] The invention relates to the field of rechargeable metal-ion electric batteries for electric vehicles.

[0002] In particular, the invention relates to a device for coating a metallic substrate with at least a solvent-free active material.

[0003] The invention also relates to a method of coating a metallic substrate for the manufacture of electrodes. Technical background

[0004] Electric battery cells are formed from an assembly of electrodes of opposite polarity separated from each other by a porous separator film. The stack of electrodes is arranged in a casing or bag, filled with an electrolyte.

[0005] The electrodes are manufactured from a metallic substrate, said metallic substrate is then coated with an ink containing at least one active material and at least one solvent.

[0006] The metallic substrates are coated using a coating device. The metallic substrates are then dried to remove the solvent. Drying is carried out in a drying oven in which the electrodes are heated and continuously rotate. Drying the electrodes is energy-intensive. Solvent removal therefore has a significant financial and environmental impact. Furthermore, solvents can be carcinogenic, mutagenic, and reprotoxic, which poses a risk to operators.

[0007] In order to eliminate the use of solvents in inks, manufacturers have developed a solvent-free coating technique known as the "dry process." This coating technique consists of depositing solvent-free active material and additives onto a metallic substrate. The substrate and the active material are passed through a calender comprising two counter-rotating rollers. In what follows, the active material and the additives are simply referred to as the "active material(s)."

[0008] This solvent-free coating technique has proven particularly difficult to master. In particular, it has been observed that maintaining a consistent thickness of active material on the metallic substrate over time is challenging. Frequent irregularities in the thickness of the active material are thus observed. The techniques Current practices therefore lead to significant waste of metallic substrate and active material, which impairs the performance of production units.

[0009] The invention aims to solve the aforementioned problems. Summary of the invention

[0010] To this end, a device for coating a metallic substrate for the manufacture of electrodes intended for electric battery cells for electric vehicles is proposed first, comprising: - a first rotating calendering roller in a first direction of rotation, - a second rotating calendering roller in a second direction of rotation opposite to the first direction of rotation, the first roller and the second roller being arranged opposite each other and at a distance from each other so as to define a passage for the metallic substrate, - at least one initial feeding device for at least one solvent-free active material on the first roller, and - at least one initial means of controlling the thickness of the active material on the first roller, a coating device in which the metallic substrate continuously passes between the first roller and the second roller such that the active material deposited on the first roller is coated at a transfer point on a first face of said metallic substrate

[0011] Thus, the thickness of the active material on the metallic substrate is maintained homogeneously over time. Irregularities in the thickness of the active material on the substrate are virtually non-existent. Production waste is significantly reduced.

[0012] Other additional features may be provided alone or in combination: - This includes: - at least one second device for feeding at least one solvent-free active material onto the second roller, and - at least one second means of controlling the thickness of the active material on the second roller, coating device in which the metallic substrate passes continuously between the first roller and the second roller so that the active material deposited on the second roller is coated at the transfer point on a second face of said metallic substrate opposite to the first face; - this one comprises only two rollers and in which the first roller has a first rotational speed and the second roller has a second rotational speed substantially equal to the first rotational speed; - the first control means and the second control means are scraper devices arranged at a predetermined scraping distance respectively from the first roller and the second roller, the first control means and the second control means being capable of removing an excess of active material deposited respectively on the first roller and on the second roller; - the first control means is arranged upstream of the transfer point according to the first direction of rotation, and the second control means is arranged upstream of the transfer point according to the second direction of rotation; - the first feeding device is arranged upstream of the first control means and downstream of the transfer point in the first direction of rotation, and the second feeding device is arranged upstream of the second control means and downstream of the transfer point in the second direction of rotation; - This includes: - a first cleaning device arranged upstream of the first feeding device and downstream of the transfer point in the first direction of rotation, said first cleaning device being capable of removing a residue of active material from the first roller, - a second cleaning device arranged upstream of the second feeding device and downstream of the transfer point in the second direction of rotation, said second cleaning device being capable of removing an active material residue from the second roller; - This includes: - a first polarization means capable of polarizing the active material at the output of the first power supply device, - a second polarization means capable of polarizing the active material at the output of the second power supply device, so that the active material moves from the first and second feeding devices to the first and second rollers respectively; - the first roller and the second roller are temperature-regulated.

[0013] Secondly, a method for coating a metallic substrate is proposed, employing a coating device as previously described, this method comprising: - a step involving the rotation of a first calendering roller, in a first direction of rotation, - a step involving the rotation of a second calendering roller in a second direction of rotation opposite to the first direction of rotation, - a step of feeding at least one solvent-free active material onto the first roller, - a step to control the thickness of the active material deposited on the first roller, a process in which the metallic substrate continuously passes between the first roller and the second roller, process in which the active material deposited on the first roller is coated on one first face of the metallic substrate.

[0014] Thus, the thickness of the active material on the metallic substrate is maintained at a consistent level over time. Irregularities in the thickness of the active material on the substrate are virtually nonexistent. Production waste is significantly reduced.

[0015] Other additional features may be provided alone or in combination: - The process includes: - a step of feeding at least one solvent-free active material onto the second roller, and - a step to check the thickness of the active material deposited on the second roller, process in which said at least one active material deposited on the second roller is coated on a second face of the metallic substrate; - the rotation speed of the first roller and the rotation speed of the second roller are substantially equal, a process in which the active material is not passed between rollers to form a film of active material before the deposition of said active material on the metallic substrate; - the process includes a step of removing excess active material from the first roller and the second roller; - the step of removing excess active material is carried out before depositing active material on the metallic substrate; - the process includes a cleaning operation intended to remove residual active material on the first roller and on the second roller, this cleaning step being carried out after the coating of the metallic substrate; - the process includes a polarization step of the active material at the output of the first feeding device and the second feeding device, said polarization step being intended to polarize the active material; - the process includes a thermoregulation step of the first roller and the second roller. Brief description of the figures

[0016] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawing in which:

[0017] [Fig.1] [Fig.1] is a schematic representation of the device for coating a metallic substrate according to the invention. Detailed description of the invention

[0018] Figure [1] shows a device for coating a metallic substrate 2 for manufacturing electrodes for electric battery cells for electric propulsion vehicles.

[0019] The coating device 1 comprises a first calendering roller 3 and a second calendering roller 4. The first and second rollers 3, 4 are arranged opposite each other and at a predetermined distance from each other so as to define a passage for the metallic substrate 2.

[0020] The first roller 3 rotates in a first direction 5 of rotation. The second roller 4 rotates in a second direction 6 of rotation opposite to the first direction 5 of rotation.

[0021] Furthermore, the coating device 1 includes at least one first active material feeding device 8. The active material is solvent-free.

[0022] The coating device 1 includes a first means 13 for controlling the thickness of the active material 9 deposited on the first roller 3. The first control means 13 makes it possible to obtain a predetermined, homogeneous thickness on the first roller 3.

[0023] The active material 9 deposited on the first roller 3 is then deposited onto a first face 10 of the metallic substrate 2. The deposition is carried out at a transfer point 11. The metallic substrate 2 moves continuously between the first and second rollers.

[0024] Thus, the thickness of the active material on the metallic substrate is maintained at a consistent level over time. Irregularities in the thickness of the active material on the substrate are virtually nonexistent. Production waste is significantly reduced.

[0025] Advantageously, the coating device 1 comprises at least a first active material feeding device 8 on the second roller. The active material is solvent-free.

[0026] The coating device 1 includes a second control means 14 for controlling the thickness of the active material 9 deposited on the second roller 4. The second control means 14 makes it possible to obtain a predetermined, homogeneous thickness on the second roller 4.

[0027] The active material 9 deposited on the second roller 4 is then deposited on a second face 12 of the metallic substrate 2 opposite the first face 10. The deposition is carried out at a transfer point 11. The metallic substrate 2 passes continuously between the first and second rollers.

[0028] Thus, the thickness of the active material on the metallic substrate is maintained at a consistent level over time. Irregularities in the thickness of the active material on the substrate are virtually nonexistent. Production waste is significantly reduced.

[0029] Advantageously, the first roller 3 has a first rotational speed. The second roller 4 has a second rotational speed substantially equal to the first rotational speed. The device 1 comprises only two rollers 3, 4. In other words, there are no other rollers between which the active material is first passed to form a film before being deposited by other rollers onto the metallic substrate.

[0030] Unlike devices with different rotational speeds, the coating is not applied abruptly. Indeed, when rotational speeds differ, there is a risk of damaging the active material. These risks are virtually eliminated with this coating device 1. State-of-the-art coating devices include more than two rollers (for example, three rollers for each side of the metallic substrate). For example, a pair of rollers where the active material is first passed to form a film of active material; these rollers have different rotational speeds. These state-of-the-art devices also include additional rollers for applying the active material to the metallic substrate.These state-of-the-art devices act abruptly on the active material, which is subjected to intense mechanical stresses due to the different rotational speeds of the rollers.

[0031] Advantageously, the first active material thickness control means 13 is a scraper device. The first control means 13 is arranged at a predetermined scraping distance 15 from the first calendering roller 3.

[0032] Similarly, the second active material thickness control means 14 is a scraper device. The second control means 14 is arranged at a predetermined scraping distance 15 from the second calendering roller 4.

[0033] The first control means 13 and the second control means 14 allow the removal of excess active material 9 deposited respectively on the first roller 3 and on the second roller 4.

[0034] The first and second control means allow for the mechanical control of the thickness of the active material on the first and second rollers. By controlling the thickness of the active material directly at the first and second rollers, production rejects are significantly reduced.

[0035] In addition, the use of scraper devices as control means makes it possible to simplify the architecture of the coating device for the benefit of better robustness and longevity over time.

[0036] Advantageously, the first thickness control means 13 is arranged upstream of the transfer point 11 along the first direction 5 of rotation. The second thickness control means 14 is arranged upstream of the transfer point 11 along the second direction of rotation.

[0037] The first and second control means thus allow the thickness of the active material on the first and second rollers to be mechanically controlled. By controlling the thickness of the active material directly at the first and second rollers and before the transfer point 11, production rejects are significantly reduced.

[0038] Advantageously, the coating device 1 comprises a first feeding device 8. The first feeding device 8 is located upstream of the first control means 13 and downstream of the transfer point 11 in the first direction 5 of rotation. The second feeding device 9 is located upstream of the second control means 14 and downstream of the transfer point 11 in the second direction 6 of rotation.

[0039] This arrangement makes it possible to significantly reduce production waste.

[0040] Advantageously, the coating device 1 includes a first cleaning device 17. The first cleaning device 17 is arranged upstream of the first feeding device 8 and downstream of the transfer point 11 in the first direction 5 of rotation. The first cleaning device 17 is suitable and intended to remove a residue 9 of active material from the first roller 3.

[0041] Advantageously, the coating device 1 includes a second cleaning device 18. The second cleaning device 18 is arranged upstream of the second feeding device 9 and downstream of the transfer point 11 in the second direction 6 of rotation. The second cleaning device 18 is suitable and intended to remove a residue 9 of active material from the second roller 4.

[0042] After the transfer point 11, residues of active material may form a film on the first and second rollers 3, 4. This compressed film of active material is likely to modify the calibration of the coating device 1 on the one hand and to modify the expected performance of the electrode on the other hand.

[0043] Advantageously, the coating device 1 includes a first polarization means suitable for polarizing the active material at the output of the first feed device 8.

[0044] The coating device 1 includes a second polarization means suitable for polarizing the active material at the output of the second power supply device.

[0045] The active material then moves from the first and second feeding devices 7,8 to the first and second rollers 4,5 respectively.

[0046] These polarization means act in such a way as to create a difference in polarity between the active material to be transferred and the first and second rollers, which are, for example, connected to ground. This difference in polarity will allow the active material to be attracted to the rollers and to adhere to them up to the transfer point 11.

[0047] Advantageously, the first roller 3 and the second roller 4 are thermoregulated.

[0048] This allows the active material to be kept in optimal conditions for coating on the metallic substrate.

[0049] In what follows, a method for coating a metallic substrate implementing the coating device 1 will be described.

[0050] The method includes a step of rotating the first roller 3 in the first direction of rotation.

[0051] The method includes a step of rotating the second roller in the second direction 6 of rotation.

[0052] The process includes a step of feeding at least one solvent-free active material onto the first roller 3.

[0053] The process includes a step of controlling the thickness of the active material deposited on the first roller.

[0054] In this process, the metallic substrate continuously moves between the first roller 3 and the second roller 4.

[0055] In this process, the active material deposited on the first roller is coated on the first face 10 of the metallic substrate 2.

[0056] Thus, the thickness of the active material on the metallic substrate is maintained at a consistent level over time. Irregularities in the thickness of the active material on the substrate are virtually nonexistent. Production waste is significantly reduced.

[0057] Advantageously, the process includes a step of feeding at least one solvent-free active material onto the second roller 4.

[0058] The process includes a step of controlling the thickness of active material deposited on the second roller 4.

[0059] In this process, the active material deposited on the second roller is coated on the second face 12 of the metallic substrate 2.

[0060] Thus, the thickness of the active material on the metallic substrate is maintained at a consistent level over time. Irregularities in the thickness of the active material on the substrate are virtually nonexistent. Production waste is significantly reduced.

[0061] Advantageously, the rotational speed of the first roller and the rotational speed of the second roller are substantially equal. In the process, the active material is not passed between rollers to form a film of active material before being deposited on the metallic substrate.

[0062] Unlike devices with different rotational speeds, the coating is not applied abruptly. Indeed, when rotational speeds differ, there is a risk of damaging the substrate or the active material. These risks are virtually eliminated with this coating device 1. By avoiding passing the active material between rollers with different speeds, the active material is not subjected to intense mechanical stresses that could damage it.

[0063] Advantageously, the method includes a step of removing excess active material from the first roller and the second roller. This removal step is carried out using the first control means and the second control means.

[0064] The first and second control means allow for the mechanical control of the thickness of the active material on the first and second rollers. By controlling the thickness of the active material directly at the first and second rollers, production rejects are significantly reduced.

[0065] In addition, the use of scraper devices as control means simplifies the architecture of the coating device, resulting in improved robustness and longevity over time.

[0066] Advantageously, in the process the step of removing excess active material is carried out before the active material is deposited on the metallic substrate.

[0067] By controlling the thickness of active material directly at the level of the first and second rollers and before the transfer point 11, production scrap is significantly reduced.

[0068] Advantageously, the process includes a cleaning operation for removing residual active material from the first and second rollers. The cleaning step is carried out after the metallic substrate has been coated at transfer point 11.

[0069] After the transfer point 11, residues of active material can form a film on the first and second rollers 3, 4. This compressed film of active material is likely to modify the calibration of the coating device 1 on the one hand and to modify the expected performance of the electrode on the other hand.

[0070] Advantageously, the process includes a step of polarizing the active material at the output of the first and second feed devices. During this polarization step, the active material is positively polarized.

[0071] These polarization means act in such a way as to create a difference in polarity between the active material to be transferred and the first and second rollers, which are, for example, connected to ground. This difference in polarity will allow the active material to be attracted to the rollers and to adhere to them up to the transfer point 11.

[0072] Advantageously, the process includes a thermoregulation step for the first and second rollers. During this step, the first and second rollers are maintained at a set temperature.

[0073] This allows the active material to be kept in optimal conditions for coating on the metallic substrate.

Claims

Demands

1. Device (1) for coating a metallic substrate (2) for manufacturing electrodes for electric battery cells for electric vehicles comprising: - a first rolling roll (3) rotating in a first direction (5) of rotation, - a second rolling roll (4) rotating in a second direction (6) of rotation opposite to the first direction (5) of rotation, the first rolling roll (3) and the second rolling roll (4) being arranged opposite each other and at a distance from each other so as to define a passage for the metallic substrate (2), - at least a first device (8) for supplying at least one solvent-free active material (9) onto the first rolling roll (3), and - at least a first means (13) for controlling the thickness of the active material (9) on the first rolling roll (3),coating device (1) wherein the metallic substrate (2) continuously moves between the first roller (3) and the second roller (4) such that the active material (9) deposited on the first roller (3) is coated at a transfer point (11) onto a first face (10) of said metallic substrate (2).

2. Coating device (1) according to claim 1 wherein it comprises: - at least one second device (9) for supplying at least one solvent-free active material (9) onto the second roller (4), and - at least one second means (14) for controlling the thickness of the active material (9) on the second roller (4), coating device (1) wherein the metallic substrate (2) passes continuously between the first roller (3) and the second roller (4) so ​​that the active material (9) deposited on the second roller (4) is coated at the transfer point (11) onto a second face (12) of said metallic substrate (2) opposite the first face (10).

3. A coating device (1) according to any one of the preceding claims, wherein it comprises only two rollers (3, 4) and wherein the first roller (3) has a first rotational speed and the second roller (4) has a second rotation speed approximately equal to the first rotation speed.

4. Coating device (1) according to any one of the preceding claims wherein, the first control means (13) and the second control means (14) are scraper devices arranged at a predetermined scraping distance (15) respectively from the first roller (3) and the second roller (4), the first control means (13) and the second control means (14) being capable of removing an excess (16) of active material deposited respectively on the first roller (3) and on the second roller (4).

5. Coating device (1) according to any one of the preceding claims wherein the first control means (13) is arranged upstream of the transfer point (11) in the first direction (5) of rotation, and the second control means (14) is arranged upstream of the transfer point (11) in the second direction (6) of rotation.

6. Coating device (1) according to any one of claims 2 to 5 wherein, the first feeding device (8) is arranged upstream of the first control means (13) and downstream of the transfer point (11) in the first direction (5) of rotation, and the second feeding device (9) is arranged upstream of the second control means (14) and downstream of the transfer point (11) in the second direction (6) of rotation.

7. Coating device (1) according to any one of the preceding claims, wherein it comprises: - a first cleaning device (17) arranged upstream of the first feeding device (8) and downstream of the transfer point (11) in the first direction (5) of rotation, said first cleaning device (17) being capable of removing a residue (9) of active material from the first roller (3), - a second cleaning device (18) arranged upstream of the second feeding device (9) and downstream of the transfer point (11) in the second direction (6) of rotation, said second cleaning device (18) being capable of removing a residue (9) of active material from the second roller (4).

8. A device according to any one of the preceding claims, wherein it comprises: - a first polarization means suitable for polarizing the active material (9) at the output of the first feeding device (8), - a second polarization means suitable for polarizing the active material (9) at the output of the second feeding device (8), so that the active material (9) moves from the first and second feeding devices (7,8) to the first and second rollers (4,5) respectively.

9. Device according to any one of the preceding claims wherein the first roller (3) and the second roller (4) are thermoregulated.

10. A method for coating a metallic substrate (2) employing a coating device according to claim 1, said method comprising: - a step of rotating a first calendering roller (3) in a first direction (5) of rotation, - a step of rotating a second calendering roller (4) in a second direction (6) of rotation opposite to the first direction (5) of rotation, - a step of feeding at least one solvent-free active material (9) onto the first roller (3), - a step of checking the thickness of the active material (9) deposited on the first roller (3), a method in which the metallic substrate (2) continuously moves between the first roller (3) and the second roller (4), a method in which the active material (9) deposited on the first roller (3) is coated on a first face (10) of the metallic substrate (2).

11. A method according to claim 10 implementing a coating device (1) according to claim 2, said method comprising: - a step of feeding at least one solvent-free active material (9) onto the second roller (4), and - a step of checking the thickness of the active material (9) deposited on the second roller (4), a method in which said at least one active material (9) deposited on the second roller (4) is coated on a second face (12) of the metallic substrate (2).

12. A method according to any one of claims 10 or 11 implementing a device according to claim 3, wherein the speed the rotation speed of the first roller and the rotation speed of the second roller are substantially equal, a process in which the active material is not passed between rollers to form a film of active material before the deposition of said active material on the metallic substrate.

13. A method according to any one of claims 10 to 12 implementing a device according to claim 4, the method comprising a step of removing excess active material from the first roller and from the second roller.

14. A method according to any one of claims 11 to 13 implementing a device according to claim 5 or 6, wherein the step of removing excess active material is carried out before the deposition of active material on the metallic substrate.

15. A method according to any one of claims 10 to 14 implementing a device according to claim 7 wherein the latter comprises a cleaning operation intended to remove residual active material on the first roller and on the second roller, this cleaning step being carried out after the coating of the metallic substrate.

16. A method according to any one of claims 10 to 15 implementing a device according to claim 8, wherein the latter comprises a polarization step of the active material at the output of the first feed device and the second feed device, said polarization step being intended to polarize the active material.

17. A method according to any one of claims 10 to 16 implementing a device according to claim 9, the latter comprising a thermoregulation step of the first roller and the second roller.

Images