SYSTEM FOR SPRAYING PARTICLES ONTO A SUBSTRATE, COMPRISING A REACTOR FOR PRODUCING THE PARTICLES TO BE SPRAYED

Abstract

A system for spraying particles onto a substrate, including: at least one reactor including at least one inlet for liquid reagents, a reaction zone, and a zone for collection of the particles produced from the liquid reagents in the reaction zone; a dispensing device allowing the particles to be sprayed onto the substrate; and a mechanism guiding the particles from the collection zone towards the dispensing device.

Claims

1-11. (canceled)

12. A system for spraying particles onto a substrate, comprising: at least one reactor comprising at least one inlet for liquid reagents, a reaction zone, and a zone for collection of the particles produced from the liquid reagents in the reaction zone; a dispensing device allowing the particles to be sprayed onto the substrate; means for guiding the particles from the collection zone towards the dispensing device; a collector of the particles; a collector of additive elements; a zone for mixing the particles and the additive elements; a nozzle for spraying a mixture of the particles and the additive elements.

13. A system according to claim 12, wherein the reactor is a microfluidic reactor, comprising plates made from silica, silicon, glass, ceramic, polymer or plastic having etched channels, or comprising capillary tubes communicating with each other.

14. A system according to claim 12, wherein the dispensing device further comprises a mixing member or ultrasound probe arranged in the zone for mixing.

15. A system as claimed in claim 12, wherein a portion downstream from the zone for mixing forms a buffer zone.

16. A system as claimed in claim 12, comprising plural reactors.

17. A system as claimed in claim 12, configured to carry out at least one battery component.

18. A system as claimed in claim 12, as a machine of additive manufacturing configured to carry out via 3D printing of at least two adjacent battery components, or a collector and an electrode formed on the collector.

19. A system as claimed in claim 12, further comprising means for sintering particles.

20. A system as claimed in claim 12, configured such that the particles coming from the reactor have a shape of which a largest dimension is less than 100 m.

21. A method for spraying particles onto a substrate using a system as claimed in claim 12, comprising: supplying the reactor with liquid reagents; controlling chemical reaction in the reactor; controlling a flow rate of particles sprayed onto the substrate by the dispensing device.

22. A method of manufacturing via 3D printing of at least two adjacent components of a battery, or a collector and an electrode formed on the collector, implemented using a system according to claim 12 and comprising: two reactors respectively configured to supply first particles and second particles, with one of the two adjacent battery components being carried out using the first particles which are first deposited then sintered, to then be used as a substrate for deposition of the second particles forming, after sintering, the other of the two adjacent battery components.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] This description will be given with regards to the annexed drawings among which:

[0043] FIG. 1 diagrammatically shows a system for spraying particles according to a preferred embodiment of the invention;

[0044] FIG. 2 diagrammatically shows a portion of the microfluidic reactor provided on the system shown in the preceding figure;

[0045] FIGS. 3a to 3c show different operating configurations of the microfluidic reactor;

[0046] FIG. 4 is a perspective view of a battery of which at least some of the components can be produced using the system for spraying particles shown in the preceding figures; and

[0047] FIG. 5 is a view diagramming a step in the manufacturing of one of the components of the battery shown in the preceding figure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0048] In reference first of all to FIG. 1, a system 1 for spraying particles P is shown according to a preferred embodiment of the invention. This system 1 is also referred to as particle deposition system or particle printing system, and has the particularity of integrating a microfluidic reactor 2 for the production of these particles P.

[0049] Indeed, the reactor 2 comprises inlets E1, E2 for the intake of liquid reagents R1, R2, with these inlets being connected to reservoirs of reagents 4a, 4b provided in the system 1 itself. These reservoirs 4a, 4b can as such be accessed from the outside of the system 1, by being protected by an exterior cover 6 of this system.

[0050] FIG. 2 shows an embodiment of the microfluidic reactor 2, formed using one or several plates 8 made from silica, silicon, glass, ceramic, polymer or plastic, having etched channels 10 for the circulation of the liquid reagents R1, R2. In addition to the inlets E1, E2, the reactors optionally comprise an inlet E3 for the intake of oil.

[0051] In the downstream direction, this reactor 2 comprises a zone for intake and mixing 12, a reaction zone 14, a heating zone 16, as well as a zone 18 for the collection of the particles P. The heating zone 16 makes it possible to heat the generated particles at high temperature, in order to favour the oxidation thereof. Alternatively, the heating zone can be offset off of the substrate in a stainless-steel coil brought to temperature.

[0052] This type of reactor 2 has the advantage of allowing for total control on the morphology of the synthesised particles P, thanks to the control unit 20 of the system 1. Indeed, the control unit 20 makes it possible to control the residence time of the mixture in the reaction zone 14, and as such have perfect control of the germination of the particles P. Their growth can then be controlled by managing the residence time and the temperature in the heating zone 16. Generally, the particles P desired at the outlet of the reactor 2 are particles of nanometric size, i.e. their largest dimension is between 1 nm and 1 m.

[0053] Controlling the reactor 2 can result in different operating modes, shown in FIGS. 3a to 3c. The first operating mode shown in FIG. 3a corresponds to a continuous flow rate mode in the zone 18 for the collection of the particles. In the operating mode in FIG. 3b, corresponding to a segmented mode, the reaction mixture is segmented into several units using an immiscible fluid. Finally, in the droplet mode of FIG. 3c, the reaction mixture is segmented into several units that do not touch the walls of the zone 18 in the form of a conduit.

[0054] In the case of use in continuous mode, there is the risk that the flow of the reaction mixture is not uniform, and therefore the particles do not all have the same residence time in the reactor. From this stems a risk that synthesised particles have different properties. As such, the two other fragmented injection modes are preferred, either by using two immiscible fluids, or by using a gas/liquid mixture.

[0055] According to the diversity of the particles P to be sprayed onto the substrate, the system 1 can be provided with several separate reactors, of, the type of the one described hereinabove. In this case, each one of the reactors 2 is designed to deliver particles of different natures, according to the liquid reagents used.

[0056] Returning to FIG. 1, the system 1 comprises a dispensing device 21 that makes it possible to spray the particles P onto a substrate 22. This device 21 comprises a collector of particles 24, connected to the collection zone 18 of the reactor by a conduit for guiding particles 26. This conduit 26 is provided with a control valve 30 to adjust the flow rate of particles P penetrating into the collector 24 of the dispensing device 21. The valve 30 is controlled by the unit 20 built into the system for spraying 1.

[0057] In this preferred embodiment, a mixture of the synthesised particles P with one or several additive elements Ai is desired, for example a polymer binder of the PVDF type, a carbon or metal compound, in order to favour conductivity. To do this, the dispensing device 21 is also provided with a collector 32 of additive elements Ai, this collector 32 being connected to a reservoir of additive elements 4c, integrated into the system 1. The flow rate of additive elements Ai introduced into the mixing zone 36 is controlled by a valve 39 controlled by the unit 20.

[0058] The particles P and the additive elements Ai are in a mixing zone 36 of the dispensing device 21, with this mixing zone 36 leading to a nozzle 38 for spraying the mixture of particles and additive elements onto the substrate 22.

[0059] In order to favour the mixing in the zone 36, the dispensing device 21 is also provided with a mixing member 40 arranged in this zone 36. The member 40 takes for example the form of an ultrasound probe, controlled by the unit 20.

[0060] The downstream portion of the mixing zone 36 forms a buffer zone, i.e. a reservoir for storing a quantity of mixture required in order to allow for the spraying of the mixture on demand by the nozzle 38. A valve 41 controlled by the unit 20 makes it possible to adjust the flow rate desired through the nozzle 38.

[0061] In this respect, it is noted that the projection of the particles P by the nozzle 38 is carried out in such a way as to implement a known printing technique, such as inkjet, screen-printing, aerosol jet printing.

[0062] Finally, the system for spraying 1 can also comprise conventional means for sintering 44, making it possible to consolidate the particles P after the deposition thereof onto the substrate 22. However, these means 44 could be offset from the system 1, without leaving the scope of the invention. In the case where they are built into the system 1, they are preferably controlled by the control unit 20.

[0063] According to a first application example of the invention, the system for spraying 1 is dedicated to the production of a battery component, preferably an electrode for lithium battery.

[0064] To do this, particles P are sprayed onto a scrolling sheet of aluminium, forming the substrate 22. The particles P deposited by the system 1 are then sintered in order to ensure the consolidation thereof. By way of example, the particles P are of the nanoparticles of oxides type, and are obtained using reagents. In this respect, it is noted that the precursors of nanoparticles are of the dissolved metal salt type, precipitators of the carbonate type, etc., and other elements known to those skilled in the art.

[0065] The method implemented for the continuous obtaining of the electrode 50 onto the substrate 22, comprises the supply of the reactor 2 by the operator, with liquid reagents R1, R2. Then, the other steps are controlled by the control unit 20. They include controlling the chemical reaction in the reactor 2, controlling the flow rate of particles P introduced into the dispensing device 21, controlling any flow rate of additive elements Ai introduced into the device 21, controlling the mixing probe 40, as well as controlling the flow rate of particles P sprayed onto the substrate 22 by the nozzle 38.

[0066] FIG. 4 shows a lithium battery 100 of known design, comprising the stacking of the following elements: a cathode 56, an electrolyte 58, an anode 60, a current collector 62, a cathode 56, etc.

[0067] The first example of application described hereinabove can as such allow for the production of the cathode 56 by spraying of particles onto a collector 62 in the form of a sheet of aluminium, and/or the production of the anode 60 by spraying of particles onto this collector 62.

[0068] A second example of application still relates to the batteries, but for the successive production of at least two adjacent components by 3D printing. Preferably, this is the production via 3D printing of the collector 62 and of the cathode 56 superimposed on the collector. To do this, the system 1 takes the form of an additive manufacturing machine that allows for the implementing of a method shown in FIG. 5. The machine 1 is then identical or similar to the system described hereinabove, with the particularity of having two microfluidic reactors 2, 2, each one intended to be supplied with liquid reagents R1, R2; R1, R2. The two reactors are connected to the same dispensing device 21, or to separate devices built into the machine 1.

[0069] First of all, the current collector 62 is formed by spraying of particles P coming from the reactor 2, these particles being of the metal nanoparticle type, preferably nanoparticles of aluminium. These particles P, referred to as first particles, are obtained using the following reagents R1, R2: aluminium salt, copper salt. They are sprayed onto a substrate (not shown), which can be another component of the battery 100.

[0070] After spraying, these first particles P are sintered by the dedicated means 44. The step of manufacturing of the collector 62 can be carried out in several successive layers, stacked according to the direction of stacking of the elements comprising the battery 100. Each layer of particles P is first deposited, then sintered. The, the collector 62 formed as such can be used as a substrate for the deposition of the cathode 56. The latter is indeed carried out by spraying of particles P coming from the reactor 2, with these particles being of the nanoparticles of oxides type, preferably nanoparticles of metal oxides. These particles P, referred to as second particles, are obtained using the following reagents R1, R2: Nickel salt, Manganese salt, cobalt salt, lithium salt as well as a solution that allows for the precipitation of the metallic solution such as NaOH, KOH, LiOH, Na2CO3, etc.

[0071] After spraying, these second particles P are sintered by the dedicated means 44. This step of manufacturing of the cathode 56 can be carried out in several successive layers, stacked according to the direction of stacking of the elements comprising the battery 100. Here too, each layer of particles P is first deposited, then sintered.

[0072] This series of steps is carried out as many times as necessary for integrating the battery components desired in the final part, produced by 3D printing. This part could for example integrate an electrolyte, an anode, etc.

[0073] Finally, it is noted that in this method of manufacturing, each one of the components of the battery 100 can itself by carried out using several types of particles, without leaving the scope of the invention.

[0074] Of course, various modifications can be made by those skilled in the art to the invention that has just been described, solely as non-limiting examples.