Method and line for filling containers of electrochemical cells, and cell production method

Abstract

A method of filling a container (C) of an electrochemical cell (302) with an electrolyte, the method comprising the steps of: providing a plurality of filling cells (2) and filling with an electrolyte; subsequently coupling each filling unit (2) to a respective one of said containers (C), thereby forming an integral assembly (4) for transferring electrolyte from the filling unit (2) to the container (C) to which it is coupled; the electrolyte is then transferred from the filling units (2) to the container (C) to which it is coupled, and each filling unit (2) is subsequently separated from the respective container (C) with which it has formed an integral assembly (4), wherein a step of coupling and separating between the filling unit (2) and the container (C) is carried out inside a conditioning chamber (116, 116 ') delimited by walls separating the interior environment of the conditioning chamber (116, 116') from the exterior environment of the conditioning chamber (116, 116 '), the pressure and / or humidity conditions of the interior environment of the conditioning chamber (116, 116') being different from the exterior environment, and wherein the step of transferring the electrolyte from the filling unit (2) to the container (C) to which it is coupled occurs at least partially in the environment outside the conditioning chamber (116, 116 ').

Description

[0001] The invention relates to a method and a line for filling containers of electrochemical cells with electrolyte, and to a method for producing the cells.

[0002] Although the present invention is particularly suitable for the production of batteries (primary or secondary) of the cylindrical battery cell type (such as lithium-ion batteries), the present invention is in any case applicable to the production of other electrolytic or electrochemical battery cells or other forms of battery cell packaging whose manufacture requires a dry environment, such as prismatic battery cells or pouch battery cells.

[0003] Battery production lines, such as those for producing lithium-ion batteries, require that at least some processing steps be performed in a "dry chamber", i.e. a sealed and ultra-dry chamber, i.e. with extremely low controlled humidity (typically of the order of 1% by volume) and with a dew point that may be below -40° C. This occurs in particular in cases where the electrode materials and / or the electrolyte filling the battery are humidity sensitive (i.e. they react with water).

[0004] The volume of the drying chamber housing the production line is usually of the order of 10,000-20,000 cubic meters and requires very high energy consumption (of the order of 500 kW or even more) for the generation and circulation of the airflow and its cooling, drying and heating.

[0005] Additionally, workers entering such dry environments need to take specific precautions (basically their clothing and the length of time they are allowed to remain) to prevent health issues, such as eye and skin problems.

[0006] Another disadvantage of conventional battery production lines is that certain materials (such as zinc, copper and / or nickel) cannot be used as the main material in the machine parts forming the line because their dust would interfere with the electrolyte or the electrodes. Therefore, it is necessary to design or redesign the machine, especially the machine located inside the drying chamber, so that the corresponding parts are made of materials other than the materials that cannot be used (i.e. materials compatible with the manufacture of batteries).

[0007] Another not insignificant problem is related to the cleaning of conventional drying chambers, which requires a lot of time and electricity to restore the ultra-dry state.

[0008] The object of the present invention is to provide a battery production method and a production line, as well as a related electrolyte filling method and a filling station, which are able to improve the known art in one or more of the above-mentioned aspects.

[0009] Within this aim, an object of the invention is to reduce the energy consumption resulting from the use of a drying chamber for the production of batteries.

[0010] Another object of the invention is to eliminate or in any case reduce the health risks for workers operating on a battery production line requiring a drying room.

[0011] Another aim is to reduce the complexity associated with air circulation systems and reduce the time required to restore an ultra-dry environment.

[0012] Another object is to be able to use components that are primarily made of materials that are not normally allowed in battery production machines, such as zinc, copper and / or nickel.

[0013] Furthermore, another object of the present invention is to overcome the disadvantages of the known art in a way that replaces any existing solutions.

[0014] Another object of the present invention is to provide a battery production method and production line and a filling method for a battery production line that are highly reliable, easy to implement and low in cost.

[0015] This aim and these and other objects which will become more apparent hereinafter are achieved by a method for filling a container of an electrochemical cell with an electrolyte according to claim 1 , optionally with one or more of the features of the dependent claims.

[0016] The aim and objects of the invention are likewise achieved by a method for producing a battery according to claim 14 .

[0017] The aim and objects of the invention are likewise achieved by a filling thread according to claim 15 , optionally with one or more of the features of the dependent claims.

[0018] Further features and advantages of the present invention will become more apparent from the description of a preferred but non-exclusive embodiment of the invention illustrated by way of non-limiting example in the accompanying drawings, in which:

[0019] - Figure 1 is a block diagram of a battery production line according to the present invention;

[0020] - Figure 2 It is a block diagram of the machinery of the production line in the previous figure;

[0021] - Figure 3 is a plan view of a filling device according to a first embodiment of the present invention;

[0022] - Figure 4a-4b The path of the container and the path of the filling unit in the station of the previous figure are shown respectively;

[0023] - Figure 5 is a perspective view of a filling kit for use in a filling device according to the present invention;

[0024] - Figure 6is an axial cross-sectional view of the kit of the previous figure;

[0025] - Figure 7 Corresponding to the previous figure, but the filling unit is being fixed to the puck of the receiving container;

[0026] - Figure 8 Corresponds to the previous figure, but the fixture is activated to form an integral assembly;

[0027] - Fig. 9 is a plan view of a filling device according to a second embodiment of the present invention;

[0028] - Fig.10 is a P&ID diagram of the previous figure, which can also be applied to the first embodiment of the filling device.

[0029] Referring to the accompanying drawings, a battery production line according to the present invention, generally indicated by reference numeral 1, generally includes a component 301 for manufacturing electrodes, a component 302 for assembling battery cells, and an optional component 303 for finishing battery cells, however, the component 303 can be separated from line 1.

[0030] The line 1 is preferably an at least partially continuous production line and is particularly suitable for producing batteries of the cylindrical cell type, such as lithium-ion batteries. However, the electrochemical cells that can be manufactured with the line 1 can also be prismatic, pouch or button cell cells.

[0031] In the following discussion, for simplicity, reference will be made to the production of a single cylindrical battery cell.

[0032] Each assembly 301, 302, 303 comprises one or more processing stations, each consisting of a device suitable for performing one or more operations on one or more elements that will constitute the final battery cell (or, in the case of an assembly 303 for finishing a battery, on the final battery cell). A dehumidification unit 400 is associated with at least one of these processing stations.

[0033] Specifically, the assembly 301 for manufacturing an electrode may include:

[0034] - a mixing station 310 adapted to perform a step of mixing raw materials of the electrode (for example, a graphite-based material for the anode and separately a lithium metal oxide-based material for the cathode) with a conductive binder to form a mixture with a solvent;

[0035] - a covering station 311 suitable for carrying out a step of covering the respective sheets of anode and cathode (whose function is to act as current collectors) with the mixture obtained from station 310;

[0036] - a drying station 312 which receives the covered sheet from the station 311 and performs evaporation of the solvent of the mixture;

[0037] - a compression station 313 suitable for carrying out a compression operation (for example by calendering) of the dried sheet arriving from the station 312;

[0038] - An optional cutting or "slitting" station 314 for cutting the electrode sheet arriving from the compression station 313 into narrower strips that will become the electrodes of the battery cells.

[0039] The components 302 for assembling a battery cell may include:

[0040] a stacking station (if the production line is for pouch-type cells) or a winding station 320 (if the production line is for cylindrical or prismatic cells) for stacking the strips of cathodes and anodes arriving from the assembly 301 for making electrodes, so as to obtain a stack (just called “stack”) or a roll (called “jelly roll”) in which a spacer layer is inserted between the cathode and anode layers;

[0041] - a station 321 for connecting contact terminals or "tabs" to the (stacked or wound) electrodes arriving from the previous station, for example using laser welding or ultrasonic welding;

[0042] - a station 322 for inserting the (stacked or wound) electrodes into corresponding casings (cylindrical or prismatic bags depending on the type of cell to be produced). For cylindrical cells, the casings are essentially cylindrical cans open at the insertion end. The casings may optionally be housed in corresponding conveyor discs in the station 322 and / or in a downstream station (as better described below);

[0043] - a station 323 for closing the housing, in which the cell housing containing the electrodes (stacked or rolled) arriving from station 322 is sealed with a cover, so as to obtain a container C. However, an access port is preferably left on the closing cover in order to allow the subsequent filling of the container C with electrolyte;

[0044] - Means 100 or 100 'for filling the container C with an electrolyte, which is usually in liquid or gel form. For example, for lithium-ion batteries, the electrolyte may consist of a lithium salt dissolved in a non-aqueous organic solvent and optional additives, or it may be another fluid or gel commonly used as an electrolyte in batteries of this type. The filling means may include means for sealing the filled container C', or followed by means for sealing the filled container C', which means are suitable for sealing (for example with a stopper) the inlet for filling the container C with the electrolyte, thereby completing the battery cell.

[0045] Finishing assembly 303, which may be optionally separate from line 1, may include:

[0046] - a formation station 330 in which the steps of charging and discharging the battery cells are carried out, in particular according to predefined voltage and current curves;

[0047] an aging station 331 in which the battery cells arriving from the forming station are stored and monitored for a period of time (optionally at different temperatures), for example by periodically measuring the open-circuit voltage;

[0048] - An end-of-line or EOL test station 332, where the battery cells stored in the burn-in station are further inspected (eg, for any losses).

[0049] According to one aspect of the invention, one or more processing stations (such as a station for filling a device) that perform steps of a production process in which an ultra-dry environment is required include walls that enclose a space to form an environmental conditioning chamber (more specifically a drying chamber), which is advantageously maintained at a higher pressure than the external environment by injecting ultra-dry air from a dehumidification unit 400 to which the environmental conditioning chamber is connected (and optionally dedicated to the environmental conditioning chamber) into the processing station.

[0050] The side walls of the conditioning chamber (or more particularly the drying chamber) are advantageously fixed to a supporting frame, footing or table of an apparatus constituting the treatment station or forming part thereof, such as a supporting frame, footing or table of a filling apparatus.

[0051] By using a dedicated drying chamber advantageously forming a single block with the corresponding filling means, the volume of the space where the humidity is significantly reduced is thus minimized and can be, for example, less than 20 cubic meters (for example between 5 and 15 cubic meters), thereby significantly saving electricity used to maintain the ultra-dry environment in such a chamber. Through this reduced volume, the operations of cleaning and restoring the ultra-dry environment are also significantly reduced and simplified.

[0052] By virtue of the higher pressure continuously maintained in such a dedicated drying chamber, contaminants or moisture can be prevented from entering the drying chamber even if there are one or more passage openings on at least one wall of the drying chamber (which passage openings are suitable for continuous or otherwise passage of products processed in the ultra-dry environment at the processing station in the inlet and / or outlet).

[0053] By defining the space where an ultra-dry environment is required, workers can operate freely along the battery production line 1 without the special design required for conventional drying rooms, and without the associated risks, because during operation of the line 1, the workers will always operate outside the station equipped with the corresponding drying room.

[0054] The device equipped with a drying chamber can optionally be designed so that parts made mainly of materials incompatible with battery production or with the processes performed by the device are left outside its drying chamber while remaining inside the device. For example, a motor with copper windings can be located outside the drying chamber and connected by a gear transmission to moving parts that manipulate or convey the product inside the drying chamber.

[0055] In a preferred embodiment of the invention, the conditioning chamber 116 (or 116', depending on the embodiment shown in the drawings) is a dry chamber and is integrated in a station involving filling the container C with electrolyte. The conditioning chamber 116, 116' is defined or delimited by a (humidity-tight) wall that separates the environment inside the conditioning chamber from the environment outside the conditioning chamber. The pressure and / or humidity conditions of the environment inside the conditioning chamber (116, 116') differ from those of the external environment.

[0056] The walls delimiting the regulating chamber 116, 116' (laterally, above and below) surround at least some operating parts of the filling device 100, 100' (such as those that perform the filling of the filling unit and the coupling and disconnection steps described below) so as to be able to maintain in the chamber 116, 116' a given higher pressure ΔP1 (i.e. a slight overpressure) relative to the pressure outside the environment, in particular above the atmospheric pressure. This preset higher pressure ΔP1 is suitable for preventing contaminants and moisture from entering the chamber 116, 116' and can be comprised between 10 and 20 Pascals, for example 15 Pascals.

[0057] The filling device 100, 100' comprises a first path P1 for conveying a series of containers C to be filled, which arrive from the station 322 or 323 and, as previously mentioned, are housings preferably closed by a cover and contain the electrodes of the battery, for example in the form of a roll or "roll-on". The containers C are preferably conveyed in a continuous movement from the inlet 10, 10', through which the containers C to be filled enter the device 100, 100', to the outlet 11, 11', through which the containers C already filled with a predetermined volume of electrolyte (the filled containers are also indicated here with C') leave the station.

[0058] The inlet 10, 10' and the outlet 11, 11' are preferably in the form of passages and are connected to a channel opening, which is present on the wall of the conditioning chamber 116, 116' and has an area S1, which is preferably the minimum value required to allow the transport container C or C' and the linear conveyors 10a, 10a' and 11a, 11a' for the containers (such as belt, chain, roller or screw feed conveyors) to pass through.

[0059] The inlet passage 10, 10' and / or the outlet passage 11, 11' may also be kept at an extremely low humidity level, for example because they are connected to other drying chambers in other stations or groups of stations for performing processes upstream and / or downstream of the filling device 100, 100'.

[0060] Considering that the internal volume of the container C is mostly occupied by electrodes, for example in the form of "jelly jelly", these electrodes hinder what could be a faster introduction of the electrolyte into the container C and these electrodes make it preferable to use a solution comprising a buffer station 110, 110' (which will be described below).

[0061] The container C may have a cylindrical shape with a circular base, as in the case shown in the drawings, or a prismatic, bag-shaped or button-shaped shape.

[0062] In a preferred embodiment of the invention, each container C, at least along the first path P1, is advantageously housed in a respective conveying disc 3, which is a beaker-shaped body open above its edge 31, so as to allow the container C to slide (automatically) into the disc through the edge 31, leaving its upper inlet 30 exposed, and stabilizing it during the various operations along the entire first conveying path P1' and optionally along the paths upstream and / or downstream of the filling devices 100, 100'.

[0063] The disc 3 is preferably adapted to remain integral with the container C at least along the entire first path P1 by means of an interference fit coupling and / or a form fit coupling with the outer surface of the container C, but preferably leaving at least one transverse gap 36 in order to allow the creation of a vacuum in the container C before filling it and / or in order to allow the container C to be cleaned before and / or after filling it with electrolyte. For example, the disc 3 may also have a substantially cylindrical shape. The disc 3 may be, for example, a hopper or a bucket.

[0064] The disk 3 may have a fixing surface on its lateral surface, for example in the form of at least one recess 32 which, in the embodiment shown, is coaxial with the central axis of the disk and is advantageously annular. The fixing surface 32 is preferably arranged near the upper edge 31 of the disk 3.

[0065] On the end axially opposite to the edge 31, the disc 3 has a base 33 suitable for providing internal support for the containers C and / or in any case externally providing a resting surface for conveying the disc and therefore the containers C along at least the first conveying path P1 or some sections thereof. The base 33 may have at least one through hole 34, for example in the center, to provide an optional access for cleaning the containers C after they have been filled, or to provide an optional ventilation opening during the insertion / removal of the containers C relative to the disc 3 and / or during the creation of a vacuum in the containers C before they have been filled, as described below.

[0066] The lateral surface of the disc 3 may have an enlarged radial portion 35 which substantially acts as a radial spacer when the discs are side by side, in particular on and preferably outside the buffer stations 110, 110' (described below) associated with the filling devices 100, 100'.

[0067] The filling device 100, 100' further comprises a second path P2 for conveying a series of filling units 2. The filling units 2 are generally syringe-shaped units that can be moved along the second path P2, which is preferably a closed path. The second path P2 at least partially overlaps the first conveying path P1, so that in the overlapping portion, the filling units 2 and the corresponding containers C overlap each other in the axial direction, i.e. parallel to a (vertical) direction that is substantially perpendicular to the floor on which the filling device 100 or 100' is mounted. The filling units 2 are preferably conveyed along at least some of the second paths P2 in a continuous motion.

[0068] Each filling unit 2 generally comprises a syringe-like unit provided with a reservoir 21 suitable for containing in its internal first chamber 21 a a predetermined volume of electrolyte to be transferred to the respective container C. To this end, the reservoir 21 comprises a bottom opening 20 for the passage of the electrolyte, which may (although not necessarily) have a diameter of the order of a few millimeters (e.g. 2-3 mm) and which may advantageously be connected to an upper inlet 30 of the respective container C, for example by providing the opening 20 with a spout 20 a protruding outwardly from the reservoir 21 .

[0069] The reservoir 21 is associated with a plunger 22, and the plunger 22 can be axially moved relative to the reservoir 21 by a guide body 24 fixed to the reservoir 21 (for example, fixed to the reservoir 21 by means of a flange connection as in the illustrated embodiment). Specifically, the guide body 24 of the plunger 22 is provided with a tubular guide 242, which is coaxial with the reservoir 21 but outside the reservoir 21, and the plunger 22 is associated in the tubular guide 242 so that the plunger 22 can slide.

[0070] The plunger 22 comprises a piston 23 which is fixed to or integral with the plunger 22 and which can slide in an airtight manner along the inner side wall of the reservoir 21 and divides the inner space of the reservoir into a first chamber 21a for containing the electrolyte to be transferred to the container C and a second chamber 21b for containing a gas under pressure (e.g. air) which is suitable for moving the piston 23 in a direction of expanding the volume of the second chamber 21b of the reservoir 21 while reducing the volume of the first chamber 21a of the reservoir 21 by its expansion, in such a way that the electrolyte leaves the opening 20. To this end, the plunger 22 comprises an internal coaxial channel 25 which is connected to the second chamber 21b and which is closed at the other end along the axis of the plunger 22 by a non-return valve 28 which can only be opened mechanically in order to introduce gas into the second chamber 21b of the reservoir 21 or to discharge gas therefrom.

[0071] The kit formed by the filling unit 2 and the corresponding disc 3 also includes temporary fixing means 27 suitable for coupling together and temporarily integrating the filling unit 2 and the container C, and more specifically, the filling unit 2 and the disc 3 (if any), and thus forming, for example, Figure 8 The overall assembly 4 is shown.

[0072] Temporary fixing means 27 are preferably associated with each filling unit 2, but they may alternatively be provided on the disc 3, if present.

[0073] The temporary fixing device 27 may be provided with one or more claws 271 , for example having a gripper formed by a plurality of said claws 271 which can move towards / away from each other around the central axis of the filling unit 2 .

[0074] In other embodiments not shown, the temporary fixing means may use other snap-action coupling means to perform temporary fixing by interference or friction fit (eg, using a threaded coupling).

[0075] The mutual approach and spacing between the drive slider 274 and the guide body 24 in the axial direction respectively cause the separation and fixation between the filling unit 2 and the disk 3, that is, the hooks 272 of the claws 271 are spaced apart and approached from each other along the corresponding axial planes.

[0076] In both of its embodiments, the filling device 100, 100' comprises a filling station 13 (such as a filling turntable 130, 130') and a coupling station 14 (such as a coupling turntable 140, 140'), the filling station 13 being configured to fill the filling units 2 with electrolyte, the coupling station 14 being configured to couple each filling unit 2 to a corresponding one of the containers C to form an integral assembly 4 for transferring electrolyte from the filling unit 2 to the container C coupled thereto.

[0077] The coupling of each filling unit 2 with the corresponding container C at the coupling station 14 comprises a first sub-step of alignment between the filling unit 2 and the container C, wherein the filling unit 2 and the container C are aligned and close to each other, and a second sub-step of sealing connection, wherein a fluid-tight connection is formed between the filling unit 2 and the container C. A vacuum may be created in the container C before transferring the electrolyte.

[0078] The filling device 100, 100' further comprises a separation station 12 adapted to separate each (empty) filling unit 2 from the corresponding (filled) container C with which the filling unit 2 once formed an integral assembly 4. The separation station 12 is preferably a separation turntable 120, 120' configured to axially separate the empty filling unit 2 from the corresponding container C filled with a predetermined volume of electrolyte.

[0079] The filling station 13, the coupling station 14 and the separation station 12 are arranged inside the conditioning chambers 116, 116'. The first conveying path P1 of the container C extends along a first portion located inside the conditioning chambers 116, 116' (passing along the path from the filling station 13 to the coupling station 14) and along a second portion located at least partially outside the conditioning chambers 116, 116' (from the coupling station 14 to the separation station 12), so that the transfer of electrolyte from the filling unit 2 to the container C coupled thereto can occur at least partially in an environment outside the conditioning chambers 116, 116'.

[0080] Furthermore, as in the second embodiment, the filling device 100 ′ may include a sealing turntable 150 ′ adapted to block the inlet 30 of the container C through which the container C was filled with electrolyte.

[0081] Each of the above-mentioned turntables is rotatable (preferably in a continuous motion) about a respective central rotation axis, which for all turntables is preferably vertical.

[0082] Each turntable 120, 120', 130, 130', 140, 140' and 150' is advantageously provided with a plurality of clamping devices which are evenly arranged along its periphery and are suitable for holding at least a respective filling unit 2 and / or a respective container C or a respective disc 3 containing a container C during a rotation of the respective turntable.

[0083] Advantageously, transfer star wheels are also arranged upstream and downstream of each of the turntables 120, 120', 130, 130', 140, 140' and 150' so as to transfer the conveyed objects (filling units 2, containers C-C', integral components 4) from one turntable to another or from one turntable to a linear conveyor and vice versa.

[0084] The first conveying path P1 and the second conveying path P2 comprise a circumferential arc which is ideally followed by the gripping means of the conveyor belt and the conveying star wheel when they rotate about the respective central rotation axes. The arcs of the first path P1 and the second path P2 preferably overlap along a circumference which is ideally followed by the gripping means of the separation carousel 120, 120' and the coupling carousel 140, 140'.

[0085] The other overlapping sections between the first path P1 and the second path P2 are along the buffer stations 110, 110' and along the feed conveyors 107, 107' for the monolithic assemblies 4 to / from the buffer stations 110, 110'. Preferably, a portion of such feed conveyors and unloading conveyors passes through passages 109, 109' connected to the side walls of the conditioning chambers 116, 116' and they pass through the walls at passage openings, each or all of which have a preset cross section S2, which is preferably minimized in order to be able to maintain a changed pressure relative to the atmospheric pressure inside the conditioning chambers 116, 116' and optionally inside the passages 109, 109'.

[0086] The monolithic assembly 4 is conveyed along a portion of the conveying path in which P1 and P2 overlap, which portion exits the conditioning chamber 116, 116' and re-enters the conditioning chamber 116, 116' before the separation operation after having traveled a certain portion outside the conditioning chamber or drying chamber 116, 116'. Such a portion of the conveying path is preferably arranged in a buffer station 110, 110'.

[0087] The buffer stations 110, 110' are arranged along the overlapping part of the paths P1 and P2 from the connecting turntables 140, 140' to the separating turntables 120, 120', and are associated with the feeding conveyor 107, 107' and the unloading conveyor 108, 108' of the integral component 4, and respectively feed the integral component 4 to the buffer stations 110, 110' at the production speed of the filling device 100, 100' with the feeding conveyor 107, 107' of the integral component 4, and unload from the buffer stations 110, 110' at the production speed of the filling device 100, 100' with the unloading conveyor 108, 108' of the integral component 4.

[0088] The buffer station 110, 110' is preferably located outside the conditioning chamber 116, 116'.

[0089] The buffer station 110, 110' is a collector of the FIFO (First In First Out) type and can be a component of a collector table or a collector conveyor, preferably arranged outside the filling device 100, 100' and outside the conditioning chamber 116, 116', for example beside or above the filling device 100, 100'. The FIFO collector can have one or more moving mats, conveyor belts, motorized roller conveyors or sliding surfaces, which are optionally arranged to form a serpentine route and in any case are suitable for accumulating a certain number (a large number) of monolithic assemblies 4 (specifically N*t monolithic assemblies, where N is the production speed of the filling device 100 or 100' in containers C' per minute, and t is the time to fill a single container C with a predetermined volume of electrolyte - in minutes), which is achieved by distributing the containers on a sufficient surface or making them travel a tortuous and / or extended path so that they stay in the buffer station 110, 110' for a period of time necessary for the containers C of the monolithic assembly 4 to be filled with the corresponding predetermined volume of electrolyte.

[0090] The monoliths 4 preferably arrive successively in neat rows at the buffer stations 110 , 110 ′ and are optionally spaced apart from one another at the same spacing as between the gripping devices of the carousels of the filling devices 100 , 100 ′ and between the reservoirs of the transfer starwheels.

[0091] The buffer stations 110, 110' are suitable for advancing monolithic assemblies 4 arriving from the feed conveyors 107, 107' towards the unloading conveyors 108, 108' at a speed and a path length defined by the time (t) required to fill a single container C with a predetermined volume of electrolyte. Such incoming monolithic assemblies 4 each comprise a filling unit 2 filled with a predetermined volume of electrolyte and containers C not yet filled with this volume.

[0092] By utilizing the pressure exerted by the gas within the second chamber 21b', this volume of electrolyte is slowly transferred to the container C of the integral assembly 4, which can continue to remain in the buffer station 110, 110' for the entire time required to complete the transfer of this volume of electrolyte from the filling unit 2 to the container C of the integral assembly 4.

[0093] By means of the buffer station 110, 110', the filling device 100, 100' can operate at a high production speed N (e.g. between 100 and 600 containers C per minute) by being able to quickly fill the filling units 2 with a carousel 130, 130' having a limited number of gripping devices and filling nozzles (e.g. in the order of several multiples of 10, e.g. between 30 and 60). Then, at the buffer station 110, 110', each filling unit 2 will autonomously fill the corresponding container C of the monolithic assembly 4 within the (longer) time t required by the internal characteristics of the container C and / or the properties of the electrolyte, by transferring the predetermined volume of electrolyte received by the filling unit 2 from the filling carousel 130, 130' in a very short time (e.g. 5 seconds) to the container C over a time t (e.g. 10 minutes). Therefore, the filling carousel 130, 130' can have a relatively small number of filling nozzles and taps (e.g. between 30 and 60).

[0094] The chambers 116, 116' are connected to the dehumidification unit 400 via transfer pipes 117, 117', which is suitable for generating and injecting an ultra-dry air flow into the chambers 116, 116', i.e., an air flow with a controlled humidity percentage of the order of several percent by volume (e.g., less than 3% by volume, more preferably less than 2% by volume or 1% by volume), and is suitable for maintaining a very low dew point, e.g., at a value of about -40°C or lower (e.g., -60°C).

[0095] Models of dehumidification units providing these performance levels are known per se, and in the case of the present invention, these dehumidification units are able to achieve a much lower energy consumption than dehumidification units used in conventional drying chambers with a volume of several thousand cubic meters. For example, for a drying chamber with a volume of around 10 cubic meters, the power required for the dehumidification unit 400 may be of the order of 30-40 kW.

[0096] The dehumidification unit 400 may include a drying or adsorption rotor (usually with a very ductile surface) impregnated with a hygroscopic material that absorbs moisture from the air, which is regenerated with a hot air flow in order to eliminate moisture accumulated on the rotor.

[0097] The flow rate of the ultra-dry air injected into the regulating chambers 116, 116' through the transfer pipes 117, 117' is based on the value of the higher pressure ΔP1 relative to the atmospheric pressure desired in the chambers 116, 116', and is determined by the range S1 and S2 of the openings for the passage of the container C and the integral assembly 4 respectively located on the walls of the regulating chambers 116, 116'.

[0098] For example, in the case where the volume of the conditioning chamber 116' is approximately 6 cubic meters and a higher pressure ΔP1 of +15 Pa relative to atmospheric pressure is maintained, the flow rate of the transferred air can be approximately 1150 cubic meters, taking into account the necessary presence of channel openings on one or more walls of the conditioning chamber in order to allow continuous transport of the product processed by the filling devices 100, 100'.

[0099] A second higher pressure ΔP2 relative to atmospheric pressure is also optionally maintained in the inlet passage 10, 10' and is preferably higher than the higher pressure ΔP1 maintained in the regulating chamber 116, 116' in order to curb the flow rate of air exhausted from the chamber itself, which flow rate might otherwise be disturbing to the operator. A difference of a few Pascals between the two higher pressures ΔP2 and ΔP1 (e.g. ΔP2-ΔP1=5Pa) may be sufficient.

[0100] Preferably, in passages 11, 11' and / or 109, 109', a pressure lower than the pressure existing in the environment outside the conditioning chamber is maintained. In particular, a slight negative pressure is maintained relative to atmospheric pressure, which is of the order of a few Pascals (e.g., a negative pressure ΔP3 of about -5Pa relative to atmospheric pressure) in order to create an air barrier that further prevents external contaminants from entering the conditioning chamber 116, 116', while still allowing air to flow from the outside toward passages 11, 11' and / or 109, 109'. Passages 11, 11' and 109, 109' can be connected to tubes or paths 118, 118', 119, 119' to exhaust air toward the suction device 115'.

[0101] The operation of the present invention is apparent from the foregoing description.

[0102] In the following, features and possible feature combinations of embodiments of the present disclosure are described as bullet lists.

[0103] Item 1. A battery manufacturing method, comprising an electrode preparation step (301) and a battery cell assembly step (302), each of the electrode preparation step and the battery assembly step comprising a plurality of processing steps for one or more components that will constitute the manufactured battery, each of the processing steps being performed by a corresponding processing station (310-314, 320-323, 100, 100'), characterized in that at least one of the processing steps is performed in a drying chamber (116, 116') of the corresponding processing station performing the processing step.

[0104] Item 2. The method of Item 2, wherein the drying chamber is maintained at a higher pressure relative to the outside of the drying chamber.

[0105] Item 3. A method according to Item 3, wherein the drying chamber is formed by a wall including at least one opening for allowing elements processed at a processing station including the drying chamber to pass therethrough and / or for allowing elements processed at a processing station including the drying chamber to pass to the outside.

[0106] Item 4. A method according to one or more of items 1-3, wherein less than 3% by volume, preferably less than 2% by volume or 1% by volume of moisture is maintained in the drying chamber, and the dew point may be less than or equal to -40°C.

[0107] Item 5. A method according to one or more of Items 1 to 4, wherein the drying chamber (116, 116') is formed by walls of a frame, a base or a table of a processing device fixed to a processing station including the drying chamber.

[0108] Item 6. A method according to one or more of Items 1-5, wherein the processing step performed in the drying chamber is a step of filling containers (C) with electrolyte, each container (C) containing electrodes of a battery cell.

[0109] Item 7. A method according to Item 6, wherein a plurality of filling units (2), each suitable for containing a predetermined volume of electrolyte, circulates along a closed path (P2), the plurality of filling units (2) are temporarily integrated with the corresponding container (C) along a portion of the closed path (P2), and are conveyed to respective buffer stations (110, 110') to autonomously fill the container (C).

[0110] Item 8. A battery production line (1), comprising a group of electrode preparation stations (301) and a group of battery cell assembly stations (302), each of the groups (301, 302) comprising a plurality of processing stations (310-314, 320-323, 100, 100') for performing corresponding processing on one or more components that will constitute the manufactured battery, characterized in that at least one of the processing stations comprises a drying chamber (116, 116') in which the corresponding processing is performed.

[0111] Item 9. Line according to Item 8, wherein the treatment station comprises walls surrounding the station defining a space of the drying chamber, the drying chamber being connected to a dehumidification unit (400).

[0112] Item 10. The line according to Item 9, wherein the dehumidification unit (400) is suitable for maintaining less than 3% by volume (preferably less than 2% by volume or 1% by volume) of moisture and a dew point less than or equal to -40°C in the drying chamber.

[0113] Item 11. The line according to one or more of Items 8-10, wherein the drying chamber (116, 116') is maintained at an overpressure relative to the outside of the drying chamber.

[0114] Item 12. A line according to one or more of Items 8-11, wherein at least one of the walls of the drying chamber comprises at least one opening for allowing elements processed at a processing station including the drying chamber to pass through it and / or for allowing elements processed at a processing station including the drying chamber to pass to the outside of the drying chamber (116, 116').

[0115] Item 13. The line according to one or more of Items 8 to 12, wherein the wall of the drying chamber is fixed to a frame, a footing or a table of a processing device of a processing station including the drying chamber.

[0116] Item 14. The line according to one or more of Items 8 to 13, wherein the at least one processing station including the drying chamber is a device or station (100, 100') for filling a container (C) containing electrodes of a battery cell with an electrolyte.

[0117] Item 15. A line according to Item 14, wherein the filling device or filling station (100, 100') comprises a plurality of filling units (2), each of which is suitable for containing a predetermined volume of electrolyte, and a device for circulating the filling units (2) along a closed path (P2), along a portion of which the filling units are temporarily integrated with the corresponding containers (C) and are transferred to a buffer station (110, 110') separate from the filling device or filling station (100, 100') to autonomously fill the containers with the predetermined volume of electrolyte.

[0118] Item 16. A line according to one or more of items 8-15, wherein the processing station including a drying chamber is selected from one or more of the following stations: a mixing station (310), a coating station (311), a drying station (312), a compression station (313), a slitting station (314), a stacking or rolling station (320), a terminal connection station (321), a station for inserting electrodes into corresponding shells (322), a station (323) for closing shells, filling devices or stations (100, 100'), a forming station (330), an aging station (331), and an end-of-line testing station (332).

[0119] Item 17. A method for filling a container (C) containing electrodes with an electrolyte to manufacture a corresponding battery cell, characterized in that the filling is performed in a dedicated drying chamber (116, 116'), which is included in the filling device or station (100, 100') performing the filling.

[0120] Item 18. The method of Item 17, wherein the drying chamber is maintained at an overpressure relative to the exterior of the drying chamber.

[0121] Item 19. A method according to Item 17, wherein the drying chamber is formed by a wall comprising at least one opening for a container (C) to be filled and / or already filled with the electrolyte to pass through, and / or for a container (C) to be filled and / or already filled with the electrolyte to lead to the outside of the filling device or station.

[0122] Item 20. A method according to one or more of Items 17-19, wherein less than 3% by volume (preferably less than 2% by volume or 1% by volume) of moisture and a dew point less than or equal to -40°C are maintained in the drying chamber.

[0123] Item 21. A method according to one or more of Items 17-20, wherein the drying chamber (116, 116') is formed by walls fixed to a frame, a base or a workbench of a filling device, and the walls of the frame, the base or the workbench of the filling device constitute the filling device including the drying chamber.

[0124] Item 22. A method according to one or more of Items 17-21, wherein a plurality of filling units (2), each suitable for containing a predetermined volume of electrolyte, circulate along a closed path (P2), and along a portion of the closed path (P2), the filling units (2) are temporarily integrated with the corresponding containers (C) and are conveyed to respective buffer stations (110, 110') to autonomously fill the containers (C).

[0125] Item 23. A station for filling containers (C) with electrolyte for use in batteries, comprising an inlet (10, 10') for empty containers (C), an outlet (11, 11') for containers (C) filled with electrolyte, and a first path (P1) for conveying containers between the inlet (10, 10') and the outlet (11, 11'), characterized in that the filling device or filling station comprises a drying chamber (116, 116') in which the corresponding process is performed.

[0126] Item 24. A filling device or filling station according to Item 23, comprising a wall surrounding the space of the station forming the drying chamber connected to a dehumidifying unit (400).

[0127] Item 25. A filling device or a filling station according to Item 24, wherein the dehumidification unit (400) is suitable for maintaining less than 3% volume (preferably less than 2% volume fraction or 1% volume fraction) of moisture and a dew point less than or equal to -40°C in the drying chamber.

[0128] Item 26. A filling device or filling station according to one or more of Items 23 to 25, wherein the drying chamber (116, 116') is maintained under an overpressure relative to the outside of the drying chamber.

[0129] Item 27. A filling device or a filling station according to one or more of Items 23 to 26, wherein at least one of the walls of the drying chamber comprises at least the inlet (10, 10') and the outlet (11, 11').

[0130] Item 28. Filling device or filling station according to one or more of Items 23 to 27, wherein the wall of the drying chamber is fixed to a frame, a footing or a table of a handling device constituting the filling device.

[0131] Item 29. A filling device or filling station according to one or more of Items 23-28, characterized in that the filling device or filling station also includes:

[0132] - a second path (P2) for conveying a series of filling units (2), said first path (P1) and second path (P2) at least partially overlapping each other;

[0133] - a separation turntable (120, 120'), a filling turntable (130, 130') of the filling unit (2), and a connecting turntable (140, 140');

[0134] wherein the buffer station (110) preferably located outside the drying chamber intersects the first path (P1) from the coupling turntable to the separation turntable,

[0135] wherein the filling turntable (130) is adapted to introduce a predetermined volume of electrolyte to be injected into the container (C) into each of the filling units (2);

[0136] wherein the coupling turntable (14) is adapted to temporarily fix a corresponding one of the filling units (2) arriving from the filling turntable (130) to each of the containers (C) so as to form an integral assembly (4) in which the filling unit (2) and the corresponding container (C) are in fluid communication;

[0137] - each of said filling units is suitable for autonomously transferring said predetermined volume of electrolyte to said container of the corresponding integral assembly (4);

[0138] The separation carousel (120, 120') is suitable for disassembling the monoblocks (4) leaving the buffer station (110, 110'), separating the emptied filling units (2) of each monoblock (4) from the corresponding filled containers (C).

[0139] In practice, it has been found that the invention fully achieves the intended aim and objects.

[0140] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. Furthermore, all the details may be replaced by other, technically equivalent elements.

[0141] In practice, the materials used (as long as they are compatible with the specific use) and the possible dimensions and shapes may be any according to requirements and the state of the art.

[0142] The disclosures in Italian Patent Application No. 102022000021240 from which this application claims priority are incorporated herein by reference.

[0143] In case technical features mentioned in any claim are followed by reference signs, such reference signs are inserted for the sole purpose of increasing the intelligibility of the claim and therefore do not have any limiting effect on the interpretation of each element represented by such reference signs by way of example.

Claims

1. A method for filling a container (C) of an electrochemical cell (302) with an electrolyte, the method comprising the following steps: - providing a plurality of filling cells (2), each filling cell being adapted to contain a predetermined volume of electrolyte; - filling each filling unit (2) with said electrolyte; Afterwards - coupling each filling unit (2) to a respective one of the containers (C) so as to form an integral assembly (4) for transferring the electrolyte from the filling unit (2) to the container (C) to which the filling unit (2) is coupled; then - transferring the electrolyte from the filling unit (2) to the container (C) to which the filling unit (2) is connected, and subsequently - separating each filling unit (2) from the corresponding container (C) with which it has formed said integral assembly (4), It is characterized in that the connecting step and the separating step are performed inside the regulating chamber (116, 116') defined by a wall separating the environment inside the regulating chamber (116, 116') from the environment outside the regulating chamber (116, 116'), the pressure and / or humidity conditions of the environment inside the regulating chamber (116, 116') are different from those of the external environment, and the step of transferring the electrolyte from the filling unit (2) to the container (C) to which the filling unit (2) is connected occurs at least partially in the environment outside the regulating chamber (116, 116').

2. The method according to claim 1, wherein: After the coupling step, the integral assembly (4) is conveyed along a conveying path away from the conditioning chamber (116, 116') and, after having traveled outside the conditioning chamber (116, 116'), re-enters the conditioning chamber (116, 116') before the separation step.

3. The method according to claim 1 or 2, wherein: During the step of transferring the electrolyte from the filling unit (2) to the container (C) to which the filling unit (2) is connected, the monolithic assembly (4) is conveyed to a buffer station (110, 110') outside the conditioning chamber (116, 116').

4. A method according to any one of the preceding claims, wherein: The wall of the conditioning chamber (116, 116') is provided with an inlet and an outlet, which are constructed and dimensioned to allow the container (C) to be filled to enter and the container (C) filled with electrolyte to leave, respectively.

5. A method according to any one of the preceding claims, wherein: The container (C) to be filled enters the regulating chamber (116, 116') by passing through an inlet passage (10, 10') which is maintained at a higher pressure than the pressure maintained in the regulating chamber (116, 116').

6. A method according to any one of the preceding claims, wherein: The regulating chamber (116, 116') is maintained at a higher pressure than the external environment.

7. A method according to any one of the preceding claims, wherein: A relative humidity of less than 3%, preferably less than 2%, more preferably less than 1% is maintained inside the conditioning chamber (116, 116').

8. A method according to any one of the preceding claims, wherein: A dew point of less than or equal to -40°C is maintained inside the conditioning chamber (116, 116').

9. A method according to any one of the preceding claims, wherein: The step of connecting each filling unit (2) to a corresponding one of the containers (C) comprises a first sub-step of alignment between the filling unit (2) and the container (C) and a second sub-step of sealing connection, in which the filling unit (2) and the container (C) are aligned with each other, in which a fluid-tight connection is established between the filling unit (2) and the container (C), and wherein after the first sub-step of alignment and before the second sub-step of sealing connection, a vacuum is generated in the container (C), and the vacuum is further generated before the step of transferring the electrolyte.

10. A method according to any one of the preceding claims, wherein: The filled container (C) passes through an outlet passage (11, 11') when leaving the regulating chamber (116, 116'), the outlet passage (11, 11') being maintained at a pressure lower than the pressure existing in the environment outside the regulating chamber (116, 116').

11. A method according to any one of the preceding claims, wherein: The step of filling each filling unit (2) with the electrolyte is performed inside the regulating chamber (116, 116').

12. A method according to any one of the preceding claims, wherein: Each filling unit (2) comprises a syringe-like unit having a reservoir (21, 21') having an opening (20) for the passage of the electrolyte, the opening (20) being connectable to an inlet (30) of the container (C), and wherein a piston (23, 23') movable in the reservoir (21, 21') is configured to transfer the electrolyte from the reservoir (21, 21') into the container (C).

13. Method according to any of the preceding claims, further comprising the step of housing each of the containers (C) in a respective conveyor disc (3) before the step of coupling each filling unit (2) to each container (C).

14. A method for producing a battery, comprising the steps of manufacturing an electrode (301) and assembling a battery cell (302), wherein the step of assembling the battery cell (302) comprises a plurality of processing steps, characterized in that: One of the processing steps comprises a filling method according to any one of the preceding claims.

15. A line for filling a container (C) of an electrochemical cell (302) with an electrolyte, comprising: - a conveying path (P1) of said containers (C); - a filling station (13) configured to fill the filling unit (2) with the electrolyte; a coupling station (14) configured to couple each filling unit (2) to a respective one of the containers (C), thereby forming an integral assembly (4) for transferring the electrolyte from the filling unit (2) to the container (C) to which the filling unit (2) is coupled; a separation station (12) configured to separate each filling unit (2) from the corresponding container (C) after transferring the electrolyte to said container (C), Characterized in that the line further comprises a conditioning chamber (116, 116'), the conditioning chamber (116, 116') being delimited by a wall separating an environment inside the conditioning chamber (116, 116') from an environment outside the conditioning chamber (116, 116'), the pressure and / or humidity conditions of the environment inside the conditioning chamber (116, 116') being different from those of the external environment, wherein the filling station (13), the coupling station (14) and the separation station (12) are arranged inside the conditioning chamber (116, 116'), And it is characterized in that the conveying path (P1) of the container (C) extends along a first part located inside the regulating chamber (116, 116') from the filling station (13) to the connecting station (14) and along a second part located at least partially outside the regulating chamber (116, 116') from the connecting station (14) to the separation station (12), so that the transfer of the electrolyte from the filling unit (2) to the container (C) to which the filling unit (2) is connected can at least partially occur in an environment outside the regulating chamber (116, 116').

16. Filling line according to claim 15, further comprising a buffer station (110) arranged outside the conditioning chamber (116, 116') and crossed by the second portion of the conveying path (P1) of the containers (C).

Images