Method for manufacturing an electrochemical cell cathode and associated installation
By using a laser to partially evaporate the solvent between deposited strips in the cathode manufacturing process, the method addresses the issue of unwanted mixing and overlapping, improving the electrical insulation and reducing short circuits in electrochemical cell cathodes.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Utility models
- Current Assignee / Owner
- AUTOMOTIVE CELLS CO SE
- Filing Date
- 2024-10-09
- Publication Date
- 2026-04-10
AI Technical Summary
The deposition of fluid compositions for electrochemical cell cathodes can result in unwanted mixing or overlapping at their interface, leading to a loss of capacitance and reduced electrical insulation, which may cause short circuits.
Incorporating a step of exposing the second strip to a laser source to partially evaporate the second solvent after deposition and before complete solvent evaporation, ensuring precise control over the interface formation between the cathode and insulating layers.
This method enhances the quality of the interface between the cathode and insulating layers, reducing the risk of short circuits and maintaining optimal electrical insulation.
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Abstract
Description
Title of the invention: Method for making an electrochemical cell cathode and associated installation
[0001] The present invention relates to a method for producing an electrochemical cell cathode, of the type comprising the following steps: a) on a substrate, deposition of a first strip of a first fluid composition, said first strip extending parallel to a principal axis, the first fluid composition comprising an active cathode material and a first solvent; b) on said substrate, deposition of a second strip of a second fluid composition parallel to the principal axis, the second fluid composition comprising a first electrical insulating material and a second solvent; the first and second strips thus forming a first interface parallel to the principal axis; c) complete evaporation of the first solvent, so as to obtain a cathodic layer on the substrate; and d) complete evaporation of the second solvent, so as to obtain a first insulating layer on the substrate;step c) taking place after step a) and step d) taking place after step b). ;
[0002] The invention applies particularly to Li-NMC (lithium nickel manganese cobalt) and / or LFP (lithium iron phosphate) and / or LMFP (lithium manganese iron phosphate) type cathodes.
[0003] During their deposition on the substrate, the first and second fluid compositions sometimes undergo unwanted mixing or overlapping at their interface. This results in a loss of capacitance and a reduction in the electrical insulation of the resulting cathode, which can lead to short circuits.
[0004] The present invention aims to provide an improvement to the process described above. To this end, the invention relates to a process of the aforementioned type, further comprising, after step b) and before step d), a step e) of exposing the second strip to a first laser source, so as to at least partially evaporate the second solvent.
[0005] According to other advantageous aspects of the invention, the method comprises one or more of the following features, taken individually or in all technically possible combinations:
[0006] - the second band has a dimension perpendicular to the main axis; and a projection of the first laser source onto the second strip covers at least 90% of said dimension;
[0007] - the first laser source has a substantially constant intensity over at least 90% of the dimension of the second band perpendicular to the main axis;
[0008] - a wavelength of the first laser source is chosen in the intervals 900- 1100 nm, 400-460 nm and 350-400 nm;
[0009] - step e) is implemented after step a) and before step c);
[0010] - step e) is implemented before step a);
[0011] - steps c) and d) are carried out simultaneously, by passing the substrate through a heating oven;
[0012] - the process further comprises the following steps: f) on the substrate, deposition of a third band of a third fluid composition parallel to the main axis, the third fluid composition comprising a second electrically insulating material and a third solvent; the first and third bands thus forming a second interface parallel to the main axis; then g) exposure of the third band to a second laser source, so as to evaporate at least partially the third solvent; then h) complete evaporation of the third solvent, so as to obtain a second insulating layer on the substrate.
[0013] The invention further relates to an installation for implementing a process as described above, said installation comprising: a displacement device, capable of moving the substrate along the main axis of said substrate; a first application device, capable of depositing the first fluid composition on the moving substrate, so as to form the first strip; a second application device, capable of depositing the second fluid composition on the moving substrate, so as to form the second strip; a drying device, capable of carrying out the complete evaporation of the first solvent and optionally of the second solvent; and a pre-drying element, comprising the first laser source; said pre-drying element being disposed between the second application device and the drying device along the main axis.
[0014] The invention further relates to an electrochemical cell cathode, comprising: a substrate; and a cathode layer and a first insulating layer, deposited on said substrate; the cathode layer having the form of a first band delimited by at least a first edge extending along a principal axis, the first insulating layer having the form of a second band extending along the principal axis along the first edge of the cathode layer, the electrochemical cell cathode being produced by a method of embodiment as described above.
[0015] The invention will be better understood upon reading the following description, given solely by way of non-limiting example and made with reference to the drawings in which:
[0016] [Fig-1] [Fig.1] is a schematic, top view of a realization installation of an electrochemical cell cathode according to a first embodiment of the invention;
[0017] [Fig.2] [Fig.2] is a detailed view of the installation of [Fig.1]; and
[0018] [Fig. 3] [Fig. 3] is a detailed, longitudinal sectional view of an installation of the realization of an electrochemical cell cathode according to a second embodiment of the invention.
[0019] Figures 1 and 3 show installations 10 and 110 for the implementation of a method for manufacturing a cathode, respectively according to a first and second embodiment of the invention.
[0020] Installations 10 and 110 will be described simultaneously below, the common elements being designated by the same reference number.
[0021] The installation 10, 110 is more specifically intended for the realization of an assembly 12 used in the manufacture of an electrochemical cell cathode.
[0022] The assembly 12 comprises: a substrate 14; a cathode layer 16; and a first 18 and a second 20 insulating layers.
[0023] The substrate 14 has the form of a first strip extending along a principal axis 21 and having a first transverse dimension 22, perpendicular to said principal axis. The substrate 14 comprises a first 23 and a second 24 opposite faces.
[0024] The substrate 14 is preferably metallic and more preferably comprises an aluminum foil.
[0025] The cathode layer 16 has the form of a second band extending over the first face 23 of the substrate 14, along the main axis 21. Said cathode layer 16 has a second transverse dimension 26, perpendicular to said main axis.
[0026] The cathode layer 16 is defined by a first 28 and a second 30 opposite edges, parallel to the main axis 21.
[0027] The first insulating layer 18 has the form of a third strip extending over the first face 23 of the substrate 14, along the main axis 21. More specifically, the first insulating layer 18 extends along the first edge 28 of the cathodic layer 16, said cathodic layer and the first insulating layer 18 being in contact with each other at said first edge.
[0028] The first insulating layer 18 has a third transverse dimension 32, perpendicular to the main axis.
[0029] The second insulating layer 20 has the form of a third strip extending over the first face 23 of the substrate 14, along the main axis 21. More specifically, the second insulating layer 20 extends along the second edge 30 of the cathodic layer 16, said cathodic layer and the second insulating layer 20 being in contact with each other at said second edge.
[0030] The second insulating layer 20 has a fourth transverse dimension 34, perpendicular to the main axis.
[0031] Preferably, the first transverse dimension 22 is greater than the sum of the second 26, third 32 and fourth 34 transverse dimensions, so that each of the first 18 and second 20 insulating layers is at a distance from an edge of the substrate 14.
[0032] Preferably, the second transverse dimension 26 is greater than the third 32 and fourth 34 transverse dimensions. Preferably, the third 32 and fourth 34 transverse dimensions are substantially equal to each other.
[0033] Preferably, as seen in [Fig.3], the cathode layer 16 has a first thickness 36; and each of the first 18 and second 20 insulating layers has a second thickness 38, less than the first thickness 36.
[0034] The installation 10, 110 comprises: a displacement device 40; a first 42, a second 44 and a third 46 application devices; a drying device 48; and a first 50 and a second 52 pre-drying elements.
[0035] The displacement device 40 is configured to move the substrate 14 in a horizontal direction. An orthonormal basis (X, Y, Z) is considered associated with the displacement device 40, with the Z direction representing the vertical. In [Fig. 1], the displacement device 40 is configured to move the substrate 14 in the X direction, with the first face 23 of said substrate oriented upwards and the principal axis 21 of said substrate parallel to X.
[0036] In the embodiment shown, the displacement device 40 comprises rollers 54 that rotate about axes parallel to Y.
[0037] The first application device 42 is configured to apply a first fluid composition 56, precursor of the cathode layer 16, to the substrate 14. The first fluid composition 56 comprises a cathode active material and a first solvent. Preferably, the first fluid composition 56 further comprises an adhesion material.
[0038] The active cathode material is, for example, of the Li-NMC (lithium nickel manganese cobalt) type, of the LFP (lithium iron phosphate) type, and / or of the LMFP (lithium manganese iron phosphate) type. In one embodiment, the active cathode material is a mixture of at least one Li-NMC type material and at least one LFP and / or LMFP type material.
[0039] The second application device 44 is configured to apply a second fluid composition 58, a precursor of the first insulating layer 18, to the substrate 14. The second fluid composition 58 comprises a first electrical insulating material and a second solvent. Preferably, the second fluid composition 58 further comprises an adhesion material. Preferably, the first electrical insulating material is suitable for forming a first ceramic-type insulating layer 18.
[0040] The third application device 46 is configured to apply a third fluid composition 60, a precursor of the second insulating layer 20, to the substrate 14. The third fluid composition 60 comprises a second electrical insulating material and a third solvent. Preferably, the third fluid composition 60 further comprises an adhesion material. Preferably, the second electrical insulating material is suitable for forming a second ceramic-type insulating layer 20.
[0041] The first 42, second 44 and third 46 application devices are, for example, slot-die type applicators. In the installation 10, 110, the first 42, second 44 and third 46 application devices are arranged above the substrate strip 14.
[0042] According to one embodiment, the second 58 and third 60 fluid compositions are substantially identical.
[0043] Preferably, each of the first 56, second 58 and third 60 fluid compositions is in the form of a suspension or “slurry”.
[0044] According to a first variant of the invention, as in the embodiment of [Fig. 1], the first 42 and second 44 application devices and / or the first 42 and third 46 application devices are aligned along Y. According to a second variant of the invention, as in the embodiment of [Fig. 3], the second 44 and / or the third 46 application device is offset along X relative to the first application device 42, as described more precisely below.
[0045] The drying device 48 is configured for the evaporation of the first, second, and third solvents of the first 56, second 58, and third 60 fluid compositions, so as to obtain the cathodic layer 16 and the first 18 and second 20 insulating layers. The drying device 48 is, for example, a convective oven extending between two open ends along X.
[0046] In the installation 10, 110, the drying device 48 is arranged along a path X of the substrate 14, downstream of the first 42, second 44 and third 46 application devices. By "downstream", it is understood that the substrate 14 passes through the drying device 48 after having interacted with the first 42, second 44 and third 46 application devices.
[0047] According to the second variant of the invention described above, the second 44 and / or the third 46 application device is closer to or further away from the drying device 48 along X than the first application device 42. For example, in the installation 110 of [Fig.3], the first application device 42 is arranged downstream of the second 44 and / or the third 46 application device, i.e. the first application device 42 is closer to the drying device 48 than the second 44 and / or the third 46 application device.
[0048] The first 50 and second 52 pre-drying organs will now be described.
[0049] Each of the first 50 and second 52 pre-drying elements is arranged above the substrate strip 14 and includes a laser source 62, capable of directing a laser beam 64 towards the substrate 14. Said laser beam 64 extends substantially parallel to Z.
[0050] In the installation 10, 110, the first pre-drying element 50 is aligned along X with the second application device 44 and disposed downstream of said second application device; and the second pre-drying element 52 is aligned along X with the third application device 46 and disposed downstream of said third application device.
[0051] Preferably, each pre-drying element 50, 52 is arranged as close as possible to the corresponding application device 44, 46.
[0052] In the installation 10 of [Fig.1], the first 50 and / or the second 52 pre-drying element is arranged downstream of the first application device 42. On the contrary, in the installation 110 of [Fig.3], the first 50 and / or the second 52 pre-drying element is arranged upstream of the first application device 42.
[0053] The laser source 62 of each of the first 50 and second 52 pre-drying elements is chosen to optimize the drying of the second and / or third solvent. In one embodiment, the laser source 62 is an infrared laser source, for example with a wavelength chosen in the range of 900-1100 nm. In another embodiment, said wavelength is chosen in the visible light, for example in the range of 400-460 nm for a blue laser. In yet another embodiment, said wavelength is chosen in the ultraviolet light, for example in the range of 350-400 nm.
[0054] A power of the laser source 62 is for example chosen between 20W and 200W.
[0055] Preferably, the laser source 62 has a substantially constant intensity over at least 90% of the transverse dimension 32, 34 of the corresponding insulating layer 18, 20. More preferably, the laser source 62 has a substantially constant intensity over at least 95% of said transverse dimension 32, 34. By "substantially constant," it is understood that the intensity is within a range of ±10% relative to an average value.
[0056] A local intensity of the laser source 62 is for example chosen between 1 W / cm2 and 100 W / cm2.
[0057] The laser source 62 of each of the first 50 and second 52 pre-drying members has a front face 66. [Fig.2] illustrates projections 70, 72, 74 along Z of said front face 66 onto the substrate 14.
[0058] According to a first embodiment, the front face 66 of the laser source 62 has a substantially square or rectangular contour, corresponding to the first projection 70. According to a second variant embodiment, the front face 66 has a substantially round, oval or oblong contour, corresponding to the second 72 and third 74 projections.
[0059] Preferably, the front face 66 has a dimension along Y greater than or equal to 90% of the transverse dimension 32, 34 of the corresponding insulating layer 18, 20. More preferably, the front face 66 has a dimension along Y greater than or equal to 95% of said transverse dimension 32, 34.
[0060] A method for realizing assembly 12 using installation 10, 110 will now be described.
[0061] First, the substrate 14 is set in motion by the displacement device 40. The substrate thus moves horizontally along its main axis 21, with the first face 23 oriented upwards. The speed of displacement is, for example, between 1 m per minute and 120 m per minute.
[0062] In parallel, the first application device 42 continuously deposits the first fluid composition 56 onto the first face 23 of the substrate, according to the so-called slot-die technique. A strip of the first fluid composition 56, precursor of the second strip forming the cathode layer 16, is thus deposited onto the substrate 14.
[0063] In parallel, each of the second 44 and third 46 application devices continuously deposits the second 58 or third 60 fluid composition onto the first face 23 of the substrate, also according to the slot-die technique.
[0064] A strip of a second fluid composition 58, precursor of the third strip forming the first insulating layer 18, is thus deposited on the substrate. The first 56 and second 58 fluid compositions come into contact with each other, to form a first interface 78, precursor of the first edge 28 described previously.
[0065] Similarly, a third fluid composition 60, precursor of the fourth band forming the second insulating layer 20, is deposited on the substrate. The first 56 and third 60 fluid compositions come into contact with each other, to form a second interface 80, precursor of the second edge 30 described previously.
[0066] It is considered that the first 56, second 58 and third 60 fluid compositions have the same second 26, third 32 and fourth 34 transverse dimensions as the cathode layer 16 and the first 18 and second 20 insulating layers, respectively. By way of example, the third 32 and fourth 34 transverse dimensions are on the order of 6 mm.
[0067] By way of example, the strips of first 56, second 58 and third 60 fluid compositions have thicknesses between 50 pm and 300 pm.
[0068] The second fluid composition strip 58 is then exposed to the laser beam 64 emitted by the first pre-drying element 50.
[0069] In the installation 10, 110, the front face 66 of the laser source 62 of the first pre-drying member 50 is arranged so that a projection along Z of said front face onto the substrate 14 covers at least 90%, preferably at least 95%, of said second fluid composition band 58 perpendicular to the main axis 21. Thus, almost the entire width of the second fluid composition band 58 is exposed to the laser beam 64.
[0070] Exposure to the laser beam 64 emitted by the first pre-drying element 50 evaporates at least partially the second solvent of the second fluid composition 58. There is therefore less risk of mixing or unintentional superposition between said second fluid composition 58 and the first fluid composition 56.
[0071] Preferably, at least 20% of the second solvent of the second fluid composition 58 is evaporated by exposure to the first pre-drying organ 50.
[0072] According to one embodiment, the laser source 62 of the first pre-drying element 50 is centered on the second fluid composition strip 58, which corresponds to the projection 70 of [Fig. 2]. According to another embodiment, said laser source is slightly off-center opposite the first fluid composition strip 56, which corresponds to the second projection 72 of [Fig. 2]. According to yet another embodiment, said laser source is slightly off-center towards the first fluid composition strip 56, which corresponds to the third projection 74 of [Fig. 2].
[0073] In the case where the first pre-drying member 50 is downstream of the first application device 42, as in [Fig.1], a laser source 62 decentered towards the band of first fluid composition 56 leads to a partial evaporation of the solvent at the first interface 78 between the first 56 and second 58 fluid compositions.
[0074] In parallel with the exposure of the second fluid composition strip 58 to the first pre-drying element 50, described above, the third fluid composition strip 60 is exposed to the laser beam 64 emitted by the second pre-drying element 52. The above description of the exposure of the second fluid composition strip 58 applies by analogy to said exposure of the third fluid composition strip 60.
[0075] According to one embodiment, a pyrometer (not shown) is coupled to each of the first 50 and second 52 pre-drying elements, so as to maintain a temperature of each laser beam 64 at a desired value. The partial evaporation of the second and / or third solvent is thus controlled.
[0076] Alternatively, the installation 10, 110 further includes a thermal camera (not shown) which monitors the surface temperature of the substrate 14, upstream of the drying device 48. Local temperature rises can thus be detected.
[0077] After the second 58 and third 60 fluid compositions have been exposed to the first 50 and second 52 pre-drying elements, respectively, the substrate 14 passes into the drying device 48. The first solvent of the first fluid composition 56 is then evaporated. Similarly, the second and third solvents of the second 58 and third 60 fluid compositions, possibly remaining after exposure to the pre-drying elements 50, 52, are completely evaporated.
[0078] Preferably, the temperature in the drying device 48 is below 180°C and more preferably between 90°C and 170°C. Indeed, it is preferable to limit the drying temperature to preserve the properties of the first fluid composition 56, precursor of the cathode layer 16.
[0079] Upon exiting the drying device 48, the first 56, second 58 and third 60 fluid compositions are hardened on the substrate 14, leading respectively to the cathodic layer 16 and the first 18 and second 20 insulating layers. The assembly 12 described above is thus obtained.
[0080] Pre-drying the first 18 and second 20 insulating layers before passing through the drying device 48 improves the quality of the interface between the cathode layer 16 and said first 18 and second 20 insulating layers.
[0081] Optionally, the process described above is then repeated by applying the first 56, second 58 and third 60 fluid compositions to the second face 24 of the substrate 14, so as to form an identical layer on both sides of said substrate
[0082] The assembly 12 is then used for example to form a cathode of an electrochemical cell.
[0083] Reference numbers: 10, 110 Cathode fabrication setup 12 Cathode fabrication assembly 14 Substrate 16 Cathode layer 18 First insulating layer 20 Second insulating layer 21 Main axis 22 First transverse dimension 23 First substrate face 24 Second substrate face 26 Second transverse dimension 28 First edge 30 Second edge 32 Third transverse dimension 34 Fourth transverse dimension 36 First thickness 38 Second thickness 40 Displacement device 42 First application device 44 Second application device 46 Third application device 48 Drying device 50 First pre-drying element 52 Second pre-drying element 54 Roller 56 First fluid composition 58 Second fluid composition 60 Third fluid composition 62 Laser source 64 Laser beam 66 Front face 70 First projection 72 Second projection 74 Third projection 78 First interface 80 Second interface
Claims
Demands
1. A method for making an electrochemical cell cathode (12), comprising the following steps: a) on a substrate (14), deposition of a first strip of a first fluid composition (56), said first strip extending parallel to a principal axis (21), the first fluid composition comprising a cathode active material and a first solvent; b) on said substrate, deposition of a second strip of a second fluid composition (58) parallel to the principal axis, the second fluid composition comprising a first electrical insulating material and a second solvent; the first and second strips thus forming a first interface (78) parallel to the principal axis; c) complete evaporation of the first solvent, so as to obtain a cathodic layer (16) on the substrate; and d) complete evaporation of the second solvent, so as to obtain a first insulating layer (18) on the substrate;step c) taking place after step a) and step d) taking place after step b); the process being characterized in that it further comprises, after step b) and before step d), a step e) of exposing the second band to a first laser source (50, 62), so as to evaporate at least partially the second solvent.
2. A method according to claim 1, wherein: the second strip has a dimension (32) perpendicular to the principal axis; and a projection (70, 72, 74) of the first laser source onto the second strip covers at least 90% of said dimension.
3. A method according to claim 2, wherein the first laser source (62) has a substantially constant intensity over at least 90% of the dimension (32) of the second band perpendicular to the main axis.
4. A method according to any one of the preceding claims, wherein a wavelength of the first laser source (62) is chosen in the ranges 900-1100 nm, 400-460 nm and 350-400 nm.
5. A method according to any one of the preceding claims, wherein step e) is carried out after step a) and before step c).
6. A method according to any one of claims 1 to 4, wherein step e) is carried out before step a).
7. A method according to any one of the preceding claims, wherein steps c) and d) are carried out simultaneously, by passing the substrate (14) through a heated oven (48).
8. A method according to any one of the preceding claims, further comprising the following steps: f) on the substrate, deposition of a third band of a third fluid composition (60) parallel to the main axis, the third fluid composition comprising a second electrically insulating material and a third solvent; the first and third bands thus forming a second interface (80) parallel to the main axis; then g) exposure of the third band to a second laser source (52, 62), so as to evaporate at least partially the third solvent; then h) complete evaporation of the third solvent, so as to obtain a second insulating layer (20) on the substrate.
9. An installation (10, 110) for carrying out a process according to any one of the preceding claims, said installation comprising: - a displacement device (40), capable of moving the substrate (14) along the principal axis (21) of said substrate; - a first application device (42), capable of depositing the first fluid composition (56) onto the moving substrate, so as to form the first band; - a second application device (44), capable of depositing the second fluid composition (58) onto the moving substrate, so as to form the second band; - a drying device (48), capable of carrying out the complete evaporation of the first solvent and optionally of the second solvent; and - a pre-drying element (50), comprising the first laser source (62); said pre-drying element being disposed between the second application device (44) and the drying device (48) along the principal axis (21).
10. Cathode (12) of an electrochemical cell, comprising: a substrate (14); and a cathode layer (16) and a first insulating layer (18), deposited on said substrate; the cathode layer having the form of a first band delimited by at least one first edge (28) extending along a principal axis (21), the first insulating layer having the form of a second band extending along the principal axis along the first edge of the cathode layer, the electrochemical cell cathode being produced by a method of embodiment according to any one of claims 1 to 8.