Continuous electrode manufacturing system and associated method

Abstract

This method for continuously manufacturing an electrode (2) comprises the following steps carried out simultaneously and continuously: continuous scrolling of a current collector (4), said current collector having a first face (A) and a second face (B) opposite the first face (A), continuous deposition of an ink (9) on the first face (A) of the current collector (4) from a reservoir (10) of ink (9), said ink comprising at least one solvent and one active material, continuous deposition of ink (9) on the second face (B) of the current collector (4), continuous drying of the deposited ink (9) to remove the solvent, by a drying device (15), said deposition of ink on the second face (B) of the collector (4) being carried out by coating with ink deposited on the first face (A) of the collector (4). Figure for abstract: [Fig 1]

Description

Title of the invention: Continuous electrode manufacturing system and associated method Technical field

[0001] The present invention relates to a method for the continuous manufacture of an electrode, for example for a metal-ion battery. Previous techniques

[0002] A metal-ion battery comprises two electrodes, namely a positive electrode and a negative electrode, misused to refer to the cathode and anode respectively, separated by an electrically insulating but ionically conductive separator. The separator is impregnated with a liquid electrolyte containing lithium ions, in the case of a lithium-ion battery.

[0003] The positive and negative electrodes are conventionally manufactured by coating, by continuously depositing an ink containing an active material, a solvent, a binder and possibly an electrically conductive additive, on the current collectors.

[0004] Conventionally, a drive roller associated with a metering blade roller is used to carry out the coating on one face of the collector. Document 2002JP-0073467 discloses a method of gravity-fed ink coating using a metering blade roller, also called a "knife" or "comma bar" in English. The disadvantage of this method is that it is not possible to simultaneously coat both faces of the collector. Indeed, to obtain a coating layer on both faces, it is necessary to first carry out the coating on a first face, then repeat all the steps of the method by reversing the direction of the collector to carry out the coating on the second face.

[0005] In order to optimize the production time by simultaneously coating both sides of a collector, the most commonly used technique is the so-called slot die coating technique.

[0006] Document US 905 06 18 - B2 illustrates this technology. Although the method described in this document makes it possible to obtain a coating layer on both sides in a single step, it uses two dedicated coating sources, each arranged on an opposite side of the collector. This multiplication of dedicated coating sources increases the complexity of the manufacturing system as well as the energy expenditure necessary for its operation. Statement of the invention

[0007] The invention aims to reduce the number of dedicated coating sources used for the manufacture of electrodes while allowing continuous production and if combined with a coating layer on each of the two opposite faces of a current collector.

[0008] The subject of the invention is a method for the continuous manufacture of an electrode comprising the following steps carried out simultaneously and continuously:

[0009] - continuous scrolling of a current collector, said current collector having a first face and a second face opposite the first face,

[0010] - continuous deposition of an ink on the first face of the current collector from an ink reservoir, said ink comprising at least one solvent and one active material,

[0011] - continuous deposition of ink on the second face of the current collector,

[0012] - continuous drying of the deposited ink to remove the solvent, by a device drying.

[0013] According to this method, the deposition of ink on the second face of the collector is carried out by coating with ink deposited on the first face of the collector.

[0014] Such a method makes it possible to use the same formulation for both sides of the collector from the same ink production and the same dedicated coating source, which promotes better homogeneity of production.

[0015] Such a method makes it possible to reduce the number of dedicated coating sources, reducing the complexity of the manufacturing system as well as the energy expenditure required for its operation.

[0016] According to one characteristic, the coating of the second face B is carried out so as to transfer half of the ink deposited on the first face of a first collector segment to the second face of a second collector segment located downstream of the first segment in the direction of movement of the collector.

[0017] For example, the coating of the second face is carried out by simultaneously passing the segments of the collector between two rollers spaced apart by a distance corresponding to the sum of the thicknesses of the segments, a thickness of the dried ink layer of the first face of the second segment and half the thickness of the ink layer deposited on the first face of the first segment.

[0018] Advantageously, the two segments of the collector form an exit angle of the two rollers ranging from 5 to 45 degrees. Such an exit angle facilitates the detachment of the two segments of the collector and makes it possible to contain the spacing between the two segments with a view to their drying in the same drying device.

[0019] Advantageously, the deposition of ink on the first face of the current collector is carried out by coating using a metering blade. Such coating is energy-efficient and makes it possible to avoid ink losses caused by the use of pumping systems required by technologies such as slot die.

[0020] For example, the deposited ink layer has a thickness ranging from 50 qm to 400 qm.

[0021] According to another characteristic, the drying device is located downstream of the ink deposition zones, in the direction of movement of the collector.

[0022] For example, the ink has a viscosity ranging from 0.001 Pa.s to 10 Pa.s.

[0023] According to another aspect, the invention relates to a continuous manufacturing system of an electrode comprising:

[0024] - means for continuously scrolling a current collector, said current collector current having a first face and a second face opposite the first face,

[0025] - means for continuously depositing an ink on the first face of the collector of current from an ink reservoir, said ink comprising at least one solvent and one active material,

[0026] - means for continuously depositing ink on the second face of the collector fluent,

[0027] - a device for continuously drying the ink deposited on the current collector to remove the solvent.

[0028] The deposition of ink on the second face of the collector is carried out by coating with ink deposited on the first face of the collector.

[0029] Preferably, the drying device comprises a single oven associated with an air extraction device. Brief description of the drawings

[0030] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

[0031] [Fig-1] schematically illustrates a continuous manufacturing system of a electrode according to one embodiment of the invention;

[0032] [Fig.2] is a detail view of the system of [Fig.l]; and

[0033] [Fig.3] illustrates a flowchart of a method for continuously manufacturing an electrode according to one embodiment of the invention. Detailed description of at least one embodiment

[0034] [Fig.l] shows a system 1 for the continuous manufacture of an electrode 2 according to one embodiment of the invention.

[0035] The manufacturing system 1 includes means for continuously advancing 3 a current collector 4 from a first coil 5 located upstream to a second coil 6 located downstream.

[0036] The current collector 4 includes a first face A and a second face B opposite the first face A. The current collector 4 is made from a sheet or strip of metal. By strip, it is meant a plate or a band formed of several superimposed films or layers. For example, the current collector 4 is made of copper or aluminum. For example, the current collector 4 has a thickness ranging from 5 µm to 25 µm.

[0037] The manufacturing system 1 includes means for continuously depositing 7, 8 ink on the current collector 4.

[0038] The deposition means 7 are configured to continuously deposit an ink 9 on the first face A of the current collector 4 from an ink reservoir 10. Preferably, the deposition means 7 comprise a roller 11 equipped with a metering blade making it possible to adjust the thickness of the ink layer 9 deposited by coating. Preferably, the thickness of the ink layer 9 ranges from 50 μm to 400 μm.

[0039] The ink 9 comprises at least one solvent, one active material and one polymeric binder enabling the active material to adhere to the current collector. The solvent may be organic or aqueous. The active material may be a positive electrode or negative electrode active material. Preferably, the ink 9 further comprises an additive, in particular a carbon-based one. Alternatively, it remains possible for the ink 9 not to contain such an additive.

[0040] For example, the ink has a viscosity ranging from 0.001 Pa.s to 10 Pa.s, and preferably, a viscosity ranging from 0.01 Pa.s to 10 Pa.s.

[0041] The deposition means 8 are configured to continuously deposit ink 9 on the second face B of the current collector 4, by coating with ink 9 already deposited on the first face A of the current collector 4.

[0042] The deposition means 8 are located downstream of the deposition means 7, in the direction of movement of the collector 4.

[0043] Such a manufacturing system makes it possible to reduce the number of dedicated coating sources. Thus, in the illustrated example, there is only one dedicated coating source, namely the ink reservoir 10.

[0044] The coating of the second face B is carried out so as to transfer ink 9 deposited on the first face A of a first collector segment 12, to the second face B of a second collector segment 13 located downstream of the first segment in the direction of travel of the current collector 4. Preferably, the coating of the second face makes it possible to transfer approximately half of the ink 9 deposited on the first face A of the first collector segment 12 to the second face B of the second collector segment 13. Such a coating makes it possible to ensure deposited ink layers of equal thickness between the two faces A and B, within tolerances. Alternatively, it remains possible for the deposited ink layers to have different thicknesses between the two faces A and B of the current collector 4.

[0045] It should be noted that although the first face A of the first segment 12 participates in the coating of the second face B of the second segment 13, it does not constitute a dedicated coating source.

[0046] Preferably, the coating is carried out by simultaneously passing the collector segments 12, 13 between two associated rollers 14a, 14b. The rollers 14a, 14b are spaced apart by a distance corresponding to the sum of the thicknesses of the segments 12, 13, a thickness of the dried ink layer of the first face A of the second segment 13 and half the thickness of the ink layer deposited on the first face A of the first segment 12.

[0047] Preferably, the distance between the rollers 14a, 14b can be adjusted to take into account the manufacturing tolerances of the different elements of the manufacturing system 1, so as to control the thickness of the ink layer 9 deposited on the faces A, B of the current collector 4.

[0048] The manufacturing system 1 further comprises a drying device 15 intended to dry the ink 9 deposited on the current collector 4 so as to remove the solvent from the ink 9. The drying device 15 is located downstream of the ink deposition zones, in the direction of travel of the collector. The ink deposition zones correspond to the locations of the deposition means 7 and 8.

[0049] Preferably, the drying device 15 comprises a single oven 16 associated with an air extraction device (not shown). The temperature of the oven enclosure 16 is set constant and ranges from 50°C to 150°C. Alternatively, depending on the desired drying dynamics, it remains possible to provide a temperature variation inside the oven enclosure 16. Alternatively, it also remains possible to provide several ovens 16.

[0050] The two segments 12, 13 of the current collector 4 form an exit angle a of the two rollers 14a, 14b ranging from 5 to 45 degrees ([Fig.2]), in order to facilitate the detachment of the two segments of the collector and to be able to dry them in the same oven 16.

[0051] Alternatively, the manufacturing system 1 may comprise means for calendering and / or cutting (not shown) the electrode formed from the current collector and the active material.

[0052] [Fig.3] illustrates a flowchart of a method for continuously manufacturing an electrode, according to one embodiment of the invention.

[0053] Although [Fig.3] illustrates successive steps, it is understood that the steps of the method are carried out simultaneously and continuously.

[0054] The method thus comprises a step 17 of continuous scrolling of a current collector, a step 18 of continuous deposition of ink on a first face A of the collector, a step 19 of continuous deposition of ink on a second face B of the collector opposite the first face A and a step 20 of continuous drying making it possible to obtain an electrode.

[0055] In a subsequent step, the electrode may be calendered. This step reduces the porosity of the electrode to improve its operation in a battery. and increase its energy density.

[0056] The electrode formed from the current collector and the active material may be wound and / or cut to the desired dimensions. This step may be carried out in the process at any time after the active material has been deposited on the current collector and after the solvent has been removed by drying. For example, this step may be carried out before or after calendering. Preferably, the cutting and / or winding steps are carried out after the calendering step.

Claims

Claims

1. A method for continuously manufacturing an electrode (2) comprising the following steps carried out simultaneously and continuously: - continuous movement of a current collector (4), said current collector having a first face (A) and a second face (B) opposite the first face (A), - continuous deposition of an ink (9) on the first face (A) of the current collector (4) from a reservoir (10) of ink (9), said ink comprising at least one solvent and one active material, - continuous deposition of ink (9) on the second face (B) of the current collector (4), - continuous drying of the deposited ink (9) to remove the solvent, by a drying device (15), characterized in that the deposition of ink on the second face (B) of the collector (4) is carried out by coating with ink deposited on the first face (A) of the collector (4).

2. Method according to claim 1, in which the coating of the second face B is carried out so as to transfer half of the ink deposited on the first face (A) of a first collector segment (12) to the second face (B) of a second collector segment (13) located downstream of the first segment (12) in the direction of travel of the collector (4).

3. Method according to claim 2, in which the coating of the second face (B) is carried out by a simultaneous passage of said segments (12, 13) of the collector between two rollers (14a, 14b) spaced apart by a distance corresponding to the sum of the thicknesses of the segments (12, 13), of a thickness of the dried ink layer of the first face (A) of the second segment (13) and of half a thickness of the ink layer deposited on the first face (A) of the first segment (12).

4. Method according to claim 3, in which the two segments (12, 13) of the collector (4) form an exit angle (a) of the two rollers (14a, 14b) ranging from 5 to 45 degrees.

5. A method according to any preceding claim, wherein the deposition of ink on the first face (A) of the current collector (4) is carried out by coating using a dosing blade.

6. A method according to any preceding claim, wherein the deposited ink layer has a thickness ranging from 50 qm to 400 qm.

7. Method according to one of the preceding claims, in which the drying device (15) is located downstream of the ink deposition zones, in the direction of movement of the collector.

8. A method according to any preceding claim, wherein the ink (9) has a viscosity ranging from 0.001 Pa.s to 10 Pa.s.

9. System for continuously manufacturing an electrode (2) comprising: - means for continuously running (3) a current collector (4), said current collector having a first face (A) and a second face (B) opposite the first face (A), - means for continuously depositing (7) an ink (9) on the first face (A) of the current collector (4) from a reservoir (10) of ink (9), said ink comprising at least one solvent and one active material, - means for continuously depositing (8) ink (9) on the second face (B) of the current collector (4), - a device for continuously drying (15) the ink deposited on the current collector (4) to remove the solvent, characterized in that the deposition of ink on the second face (B) of the collector is carried out by coating with ink deposited on the first face (A) of the collector.

10. System according to claim 9, wherein the drying device (15) comprises a single oven (16) associated with an air extraction device.

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