Device and method for filling and closing a battery cell

Abstract

The invention relates to a device for filling a battery cell (2) with an electrolyte and for subsequently closing the battery cell (2), having a process chamber (10) with a receiving opening (11), in which the battery cell (2) is at least partly received in such a way that a filling opening (12) of the battery cell (2) is situated in the process chamber (10), and with an opening (13), which is suitable for receiving at least one line (14) for filling the battery cell (2), the process chamber (10), together with the received battery cell (2) and the line (14), being gas-tight and liquid-tight. The process chamber (10) has a passage (15) through which laser beams can pass in order to close the filling opening (12) of the battery cell (2) such that the battery cell (2) at least partly received in the process chamber (10) can be filled with the electrolyte and then closed. The invention also relates to a method in which the battery cell (2) is first positioned in the receiving opening (11) of the process chamber (10). Subsequently, a vacuum is generated in the process chamber (10) and in the battery cell (2) situated in the receiving opening (11) such that the filling opening (12) of the battery cell (2) is gas-tight and liquid-tight in the process chamber (10), and the battery cell (2) is filled by means of the line (14). The filling opening (12) of the battery cell (2) is then welded by means of a laser beam which reaches the filling opening (12) of the battery cell (2) through the passage (15).

Description

[0001] title

[0002] Device and method for filling and sealing a battery cell

[0003] Description

[0004] The invention relates to a device for filling a battery cell with an electrolyte and subsequently sealing the battery cell. The invention further relates to a method for filling a battery cell with an electrolyte and subsequently sealing the battery cell using the aforementioned device.

[0005] Rechargeable battery cells are of great importance in many technical fields. They are frequently used in applications requiring only small rechargeable battery cells with relatively low currents, such as in mobile phones. However, there is also a significant demand for larger rechargeable battery cells for high-energy applications, with mass energy storage in the form of battery cells being of particular importance for the electric propulsion of vehicles.

[0006] Commercially available rechargeable battery cells are so-called lithium-ion battery cells. These cells use organic electrolytes (organic lithium-ion batteries), in which a conducting salt is dissolved in one or more liquid organic solvents. For example, the electrolyte LP30 consists of a 1 molar solution of lithium hexofluorophosphate (LiPFg) in a 1:1 mass mixture of the organic solvents ethylene carbonate (EC) and dimethyl carbonate (DMC).

[0007] Further developments of lithium-ion battery cells are also known from the prior art, which provide for the use of SC-based electrolytes instead of organic electrolytes for rechargeable battery cells.

[0008] For the purposes of the present invention, the term "SO2-based electrolyte" means an electrolyte that contains SO2 not only as an additive in low concentration, but in which the mobility of the ions of the conducting salt contained in the electrolyte, which effects charge transport, is at least partially, largely or even completely restricted by

[0009] 34704-P-WO Tue / sü 01.08.2025 SÜ2 is guaranteed. The SO2 thus serves as a solvent for the conducting salt. The conducting salt can form a liquid solvate complex with the gaseous SO2, whereby the SO2 is bound and the vapor pressure is significantly reduced compared to pure SO2. This results in electrolytes with a low vapor pressure. Such SO2-based electrolytes have the advantage of being non-flammable compared to the previously described organic electrolytes. Safety risks associated with the flammability of the electrolyte can therefore be eliminated.

[0010] Due to the steadily growing demand for battery cells, there will be increasing interest in manufacturing the rechargeable battery cells described above as efficiently and cost-effectively as possible.

[0011] The production of a battery cell includes filling it with the desired organic or SO2-based electrolyte and then sealing the battery. Filling and sealing are crucial process steps for product quality in the manufacture of rechargeable battery cells, directly impacting their lifespan and performance. In addition to product quality, the filling time is also important. The longer the filling step takes, the more costly it becomes.

[0012] According to the state of the art, organic lithium-ion batteries in cylindrical cells up to approximately 32 mm in diameter are typically manufactured using so-called open filling. In this manufacturing process, the battery casing, which is open (i.e., without a lid), is filled with the organic electrolyte. After the interior of the casing is completely filled with the electrolyte, the open casing of the battery cell is closed with a lid. Large cylindrical or prismatic cells are filled through openings in the lid assembly. However, in the case of open filling, complex measures are necessary to prevent contamination of the interior of the battery cell with, for example, moisture from the air. Furthermore, the known manufacturing process takes a very long time until the entire cell interior is filled with the organic electrolyte. In "Prospects for reducing the processing cost of lithium ion batteries" (David L.Wood III, Jianlin Li, Claus Daniel (Journal of Power Sources 275 (2015) 234-242) refers to the period of 2 to 3 days until the battery cell is completely wetted with the electrolyte. This leads to the following:

[0013] 34704-P-WO Tue / sü 01.08.2025 The manufacturing process is complex, time-consuming, and expensive. This is reflected in the price of the battery cell.

[0014] US Patent 000003911972 A deals with filling battery cells with aqueous electrolyte solutions, such as potassium hydroxide. It proposes an improved method compared to the prior art (immersion of the entire battery cell in the electrolyte solution) for filling battery cells with aqueous electrolyte solutions. The method describes filling battery cells with a precise quantity of liquid within a hermetically sealed chamber. In the disclosed method, the upper part of the casing is first inserted into the sealed opening of the chamber. Then, a vacuum is created in the chamber, thereby evacuating the interior of the chamber and the battery cell contained within it.After precisely measuring the amount of electrolyte required to fill each battery cell, a tight connection is established between the filling opening of the liquid supply device and the measured amount of electrolyte is filled through the filling opening of the housing under the influence of overpressure.

[0015] The document further describes a device for carrying out the method, consisting of a hermetically sealed chamber with a first, a second, and a third opening. The first opening contains the filling head, which extends into the filling chamber to seal around the filling port and supply the precise quantity of liquid. The second opening contains the upper part of the battery cell housing, including the filling port, which can be moved towards the filling head. The device also has openings for evacuation or for applying overpressure.

[0016] The sol-coil-based electrolytes form a solvate structure through the interaction of gaseous SO₂ with the conducting salt, leading to an increased vapor pressure of the electrolyte. This, in turn, causes SO₂ to escape in the open system, which promotes crystallization of the conducting salt when the sol-coil content of the electrolyte decreases, for example, when a vacuum is applied. Crystallization can occur, for example, in the lines of a filling apparatus or at a battery filling port. These problems are known, and various solutions have been proposed in the prior art.

[0017] DE 199 118 00 CI discloses a method and a device for filling an electrochemical cell, intended to solve the aforementioned problems associated with

[0018] 34704-P-WO Tue / sü 01.08.2025 are connected to SC-based electrolytes. As a solution to the problems, DE 199 118 00 CI proposes a complicated apparatus in which a gas-tight cannula must be inserted through an inlet opening of the battery up to the electrode stack. However, this poses the risk that the end of the cannula will damage the electrode stack and cause an internal short circuit, or that the cannula will become clogged by crystallized conducting salt. For filling, the battery cell is evacuated, and after opening a valve, the electrolyte solution is drawn into the cell.

[0019] US Patent 9,209,458 B2 proposes another method for filling battery cells with SO2-based electrolyte solution. Unlike DE 199 118 00 CI, no cannula is inserted into the battery cell; instead, the filling opening is connected to the filling system in a gas-tight manner, as described, for example, in US Patent 000003911972 mentioned above. The method comprises the following steps:

[0020] 1. A cell casing containing a positive and a negative electrode is evacuated;

[0021] 2. The inside of the casing is filled with gaseous SO2;

[0022] 3. Steps 1 and 2 are repeated if necessary;

[0023] 4. The casing is evacuated;

[0024] 5. A filling opening of the housing is connected gas-tight to a vessel containing an electrolyte solution with a predetermined concentration of SO2; and

[0025] 6. The electrolyte solution is allowed to flow into the housing, driven by pressure exerted on the electrolyte and by the vacuum prevailing in the housing.

[0026] A similar procedure is proposed for battery cells cooled to -20°C. Filling is carried out via the filling tube (30). This is attached to the lid, between the two battery terminals, as can be seen in Figures 9 and 10 of US 9,209,458 B2. This has the significant disadvantage because there is limited space between the two battery terminals.

[0027] DE 10 2022 201 087 A1 relates to a method for filling and sealing a battery cell that has a housing element with a filling opening. In a first process step, a hollow body having a through-opening is guided through the filling opening and, in a first joining phase, is connected to the housing element by plastic deformation in such a way that the through-opening remains at least

[0028] 34704-P-WO Tue / sü 01.08.2025 partially remains. In a second process step, the through-opening is used for filling the battery cell housing with electrolyte and / or for degassing. In a third process step, the through-opening is completely sealed.

[0029] However, none of the methods and devices described in the prior art provide a device and a method for filling and sealing the electrolyte-filled battery cells within this single device so that a sealed battery cell, ready for use, can be removed from the device.

[0030] Starting from the prior art, the object underlying the present invention is to provide a device and a method for filling a battery cell with an electrolyte and subsequently sealing the battery cell, in which the filling and sealing take place within a single device, the filling times are reduced compared to the times in the prior art, all battery cell designs can be filled and sealed, no electrolyte or solvent escapes when the battery cell is disconnected, the crystallization of conducting salt within the device is avoided, the device allows the filling to be carried out stably and with the highest accuracy, the filling opening of the battery cell is produced simply, quickly and efficiently, and the filling opening of the battery cell is arranged in such a way that the space requirement for the electrode winding or...-The stack is not affected, the filling opening of the battery cell is arranged in such a way that the space required for the electrode connections and additional elements, e.g. the rupture disc, in the lid assembly is not affected, all components of the battery cell are completely wetted with the electrolyte after filling to ensure good performance of the battery cell, no concentration gradients occur in the battery cell during filling, reactions between electrolyte and battery cell components are minimized, special measures for water-sensitive electrolytes can be dispensed with, and the filled battery cell is immediately sealed.

[0031] 34704-P-WO Tue / sü 01.08.2025 This problem is solved by a device for filling a battery cell with an electrolyte and subsequently sealing the battery cell with the features of claim 1, and by a method for filling a battery cell with an electrolyte and subsequently sealing the battery cell with the features of claim 11. Advantageous embodiments and further developments of the device and the method are defined in claims 2 to 10 and 12 to 18.

[0032] The device according to the invention for filling a battery cell with an electrolyte and subsequently sealing the battery cell comprises a process chamber. The process chamber is provided with a receiving opening in which the battery cell is at least partially received such that a filling opening of the battery cell is arranged within the process chamber. Furthermore, the process chamber has an opening suitable for receiving at least one line for filling the battery cell. The process chamber is designed such that it is gas-tight and liquid-tight with the received battery cell and line. In addition, the process chamber has a passage through which the laser beams for sealing the filling opening of the battery cell can pass, so that the battery cell, at least partially received in the process chamber, can be filled with the electrolyte and subsequently sealed.

[0033] The terms “gas-tight” and “liquid-tight” are used in the context of the present invention to express the inability of a gas or liquid, respectively, to enter or leave a device.

[0034] The term "for sealing by means of laser beams" is to be understood, within the meaning of the present invention, as referring to laser welding, often also called laser steel welding. In laser welding, the welding process is carried out using laser energy. The laser beam is optically focused so that a high energy input melts a very small area. In laser welding, the weld pool is protected from oxidation by a shielding gas, usually argon. In the weld pool, the workpieces and the filler metal fuse to form a weld seam. Due to the focusing of the laser beam, the heat input is limited to a small part of the workpiece, causing the weld seam to cool rapidly – ​​a consequence of the high temperature gradient between the welded area and the rest of the workpiece. Alternatively, the term can also refer to an additive process.

[0035] 34704-P-WO Tue / south 01.08.2025 Welding is possible by introducing the material for welding into the process chamber near the filling opening before the welding process.

[0036] The device according to the invention has the significant advantage that both steps, namely filling and sealing the battery cell, can be carried out in a single device. This contributes to a considerably more efficient manufacturing process for the battery cells. Furthermore, the device according to the invention, due to its simple design, can be configured to accommodate battery cells of various shapes and sizes. This contributes to the device's broad applicability.

[0037] In a further advantageous embodiment of the device according to the invention, the passage is formed from a laser beam-permeable material.

[0038] The term "laser-transparent material" is to be understood, within the meaning of the present invention, as meaning that the material is permeable to laser beams. Accordingly, any material suitable for laser welding is to be understood as a laser-transparent material within the meaning of the present invention.

[0039] This design has the advantage that the process chamber, and therefore the device according to the invention, remains gas-tight and liquid-tight without additional measures, and that it ensures that the sealing of the battery cell can be carried out simply by laser welding, as described in detail above.

[0040] In a further advantageous embodiment of the device according to the invention, the laser beam-transparent material is selected from the group comprising: glass, diamond, sapphire, polymers and thin / thick film coatings and glass fiber reinforced plastics.

[0041] For the purposes of the present invention, the term "glass" is to be understood as an amorphous, inorganic solid produced from quartz sand, lime, and soda powder by melting and subsequent controlled cooling. The term encompasses all types of glass.

[0042] For the purposes of the present invention, the term "diamond" means the cubic modification of carbon and, as a naturally occurring solid, a mineral from the mineral class

[0043] 34704-P-WO Tue / south 01.08.2025 of the elements to understand. Diamond usually forms octahedral crystals, often with curved and striated faces.

[0044] For the purposes of the present invention, the term "sapphire" is to be understood as the blue, but also yellow, green, violet and white / colorless variety of the mineral corundum.

[0045] The term “polymers and thin / thick film coatings” is to be understood within the meaning of the present invention as encompassing all commercially available and laboratory-produced polymers and coatings.

[0046] The term "glass fiber reinforced plastics" is to be understood, within the meaning of the present invention, as referring to a composite material in which a plastic matrix is ​​modified by the addition of glass fibers. Glass fibers are the most commonly used reinforcing fibers in reinforced polymers. Both thermosetting plastics (e.g., polyester resin [UP] or epoxy resin) and thermoplastic plastics (e.g., polyamide) are suitable as base materials.

[0047] In an advantageous embodiment of the device according to the invention, the laser beam-permeable material is a laser beam-permeable glass, preferably a quartz glass (SiOj).

[0048] This design has the advantage that the device according to the invention can be manufactured cost-effectively.

[0049] In a further advantageous embodiment of the device according to the invention, the part of the passage facing the interior of the process chamber is provided with a movable cover.

[0050] This design has the advantage that the passage made of a laser beam-permeable material can be protected from process gases or liquids located inside the battery cell if necessary.

[0051] In a further advantageous embodiment of the device according to the invention, the laser beam strikes the filling opening of the battery cell at an angle of preferably 90°, more preferably 80°, more preferably 75°, still more preferably 70°, and particularly preferably 65°.

[0052] This design has the advantage of ensuring maximum energy transfer during closing, thus making this step efficient.

[0053] 34704-P-WO Tue / south 01.08.2025 The angled alignment of the laser beam prevents potential damage within the battery cell, e.g. to the electrode winding or electrode stack.

[0054] It is also conceivable that a spacer, preferably in ring form, could be placed inside the battery cell housing around the filling opening to protect the electrodes.

[0055] In a further advantageous embodiment of the device according to the invention, the filling opening is formed in a housing of the battery cell.

[0056] This design has the advantage that the battery cell filling opening can be made less complex than solutions known in the prior art. For example, it can be manufactured as a simple hole in the housing, which is significantly easier to produce than a complexly welded filling tube in the housing lid.

[0057] In a further advantageous embodiment of the device according to the invention, the filling opening is arranged in the bottom area of ​​the housing of the battery cell.

[0058] This design ensures that the structure of the lid assembly is independent of the filling opening, thus providing more space for the electrode winding or stack.

[0059] In a further advantageous embodiment of the device according to the invention, the filling opening has a diameter of 5000 pm, preferably 2500 pm, more preferably 1000 pm, still more preferably 750 pm, increasingly preferably 500 pm and particularly preferably 250 pm.

[0060] In a further advantageous embodiment of the device according to the invention, the filling opening is round.

[0061] In a further advantageous embodiment of the device according to the invention, the filling opening is angular, e.g. square or rectangular.

[0062] In the case of a rectangular design, the sides have a length between 100 pm and 5000 pm, more preferably between 150 pm and 2500 pm and particularly preferably between 200 pm and 1000 pm.

[0063] 34704-P-WO Tue / south 01.08.2025 In a further advantageous embodiment of the device according to the invention, the filling opening is not centrally located in the base of the battery cell.

[0064] In a further advantageous embodiment of the device according to the invention, the line is designed to be movable in such a way that it can be positioned so that the filling opening is sealed against the interior of the process chamber by means of the line.

[0065] This design has the advantage that the electrolyte does not first enter the process chamber and then the battery cell, but rather ensures that the electrolyte enters the battery cell directly through the line via the filling opening.

[0066] In a further advantageous embodiment of the device according to the invention, the process chamber has further openings in which further lines can be received in a gas-tight manner, wherein the lines are arranged movably within the openings.

[0067] This design has the advantage that while the first line is used exclusively for transporting the electrolyte, the additional lines can be used to introduce process gases such as SO2, inert gases such as N2 and Ar, or welding gases such as helium and argon, or shielding gas mixtures such as the LASAL shielding gas mixtures from Air Liquide, into the process chamber as needed, or to create a vacuum in the process chamber. A separate vacuum line also allows for faster creation of a desired vacuum. Creating a vacuum in the process chamber also results in a vacuum in the battery cell located within the process chamber. This can be advantageous for filling the battery cell with electrolyte. Gases can also be removed from the process chamber via this line, thus simplifying maintenance of the process chamber.

[0068] The device according to the invention is suitable for filling and sealing battery cells with various electrolytes.

[0069] In a further advantageous embodiment of the device according to the invention, the electrolyte is an electrolyte comprising one or more organic solvents.

[0070] Liquid organic electrolytes are widely used in commercially available lithium-ion batteries. Liquid electrolytes, in which a conducting salt is dissolved, allow for efficient ion flow and therefore exhibit better conductivity compared to solid electrolytes.

[0071] 34704-P-WO Tue / south 01.08.2025 Various conducting salts and solvents can be flexibly combined to adapt properties such as viscosity, conductivity, temperature resistance, etc. Liquid organic electrolytes also offer a low internal resistance compared to solid electrolytes.

[0072] However, electrolytes containing organic solvents also have disadvantages. They can evaporate and decompose over time. Furthermore, safety risks can arise, as some liquid electrolytes are highly flammable and can release toxic gases. Additionally, the conductivity of liquid electrolytes can decrease at extreme temperatures. The choice of electrolyte depends on the specific requirements of the battery, including performance, safety, and environmental compatibility.

[0073] Most currently used lithium-ion electrolytes employ LiPFg as the conducting salt because LiPFg solutions exhibit high ionic conductivity (8–12 mS / cm) and acceptable safety properties. Other conducting salts include, for example, LiBF4, LiN CFaSC, or lithium bis-oxalato-borate (LiBOB). The electrolytes currently in use are almost exclusively formulated with carbonate solvents. Carbonates are aprotic, polar, and have a high dielectric constant, and can therefore dissolve lithium salts in high concentrations (>1 M). They also offer compatibility with cell electrode materials over a wide potential range. Organic solvents used include, for example, propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC), either alone or, more commonly, in mixtures. Organic electrolytes, especially those using LiPFg as the conducting salt, react with water to form toxic substances such as HF fluoride.Special measures, such as working in dry rooms, are therefore necessary when working with organic lithium-ion cells that are still open.

[0074] The device according to the invention is suitable for filling battery cells with electrolytes containing organic solvents, regardless of the type of conducting salt.

[0075] In a further advantageous embodiment of the device according to the invention, the battery cell is filled with an SC-based electrolyte.

[0076] As defined above, an SC-based electrolyte contains SO2 not just as an additive in low concentrations, but in concentrations at which the mobility of the ions of the conducting salt contained in the electrolyte, which facilitates charge transport, is at least partially, largely, or even completely ensured by the SO2. The conducting salt is in

[0077] 34704-P-WO Tue / sü 01.08.2025 dissolved in the electrolyte and exhibits good solubility. It can form a liquid solvate complex with gaseous SO2, in which the SO2 is bound. In this case, the vapor pressure of the liquid solvate complex drops significantly compared to pure SO2, resulting in electrolytes with a low vapor pressure. It is also possible that, depending on the chemical structure of the conducting salt, no vapor pressure reduction occurs during the production of the electrolyte according to the invention. The device is suitable for filling battery cells with SC-based electrolyte, regardless of the type of conducting salt.

[0078] In an advantageous embodiment of the SC-based electrolyte, the conducting salts are selected from the alkali or alkaline earth halides of Group 3A of the periodic table. Preferred 3A elements are boron, aluminum, gallium, and indium. Preferred alkali and alkaline earth metals are lithium, sodium, and calcium. Examples of preferred salts include LiAlCl₄, LiGaCl₄, LiBF₄, LiBCl₄, LilnCl₄, NaAlCl₄, NaGaCl₄, NaBF₄, NaBCl₄, NalnCl₄, Ca(AlCl₄)₂, Ca(GaCl₄)₂, Ca(BF₄)₂, Ca(BCl₄)₂, Ca(BCl₄)₂, Ca(lnCl₄)₂, Sr(AlCl₄)₂, Sr(GaCl₄)₂, Sr(BF₄)₂, Sr(BCl₄)₂, Sr(lnCl₄)₂, and mixtures thereof.

[0079] In another advantageous embodiment of the SO2-based electrolyte, the

[0080] Conductive salts selected from the conductive salts according to the following formula (I)

[0081] Formula (I) where M is a metal selected from the group consisting of alkali metals, alkaline earth metals, group 12 metals of the periodic table of elements and aluminium; x is an integer from 1 to 3; the substituents R 1 , R 2 , R 3 and R 4 are independently selected from the group consisting of C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, Cg-Ci4 aryl and C5-C14 heteroaryl; and where Z is aluminium or boron.

[0082] In a further advantageous embodiment of the SC-based electrolyte, the conducting salts are selected from the conducting salts according to the following formula (II)

[0083] 34704-P-WO Tue / south 01.08.2025

[0084] Formula (II) where M is a metal selected from the group consisting of alkali metals, alkaline earth metals, group 12 metals and aluminium; x is an integer from 1 to 3; R 1 , R 2 , R 3 and R 4 are independently selected from the group formed by a halogen atom, a hydroxyl group, a chemical group -OR 5 and a chelating ligand consisting of at least two of the substituents R 1 , R 2 , R 3 and R 4 is formed jointly and coordinated at Z; where R 1 , R 2 , R 3 and R 4 neither four halogen atoms nor four chemical groups -OR 5 , in particular alkoxy groups; wherein the substituent R 5 selected is from the group consisting of Ci-Cio alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, CB-CM aryl and C5-C14 heteroaryl; and where Z is aluminium or boron.

[0085] In another advantageous embodiment of the SO2-based electrolyte, at least two of the above-mentioned conducting salts are included.

[0086] The inventive method for filling a battery cell with an electrolyte and subsequently sealing the battery cell with the device described above comprises the following steps: a) Positioning the battery cell in the receiving opening of the process chamber so that the filling opening of the battery cell is arranged gas-tight in the process chamber, b) Generating a vacuum in the process chamber and in the battery cell arranged in the receiving opening, c) Filling the battery cell with the electrolyte by means of the line, which is arranged gas-tight in the opening and leads to the filling opening of the battery cell, d) Welding the filling opening of the battery cell by means of a laser beam, which passes through the passage to the filling opening of the battery cell, e) Removing the sealed battery cell from the receiving opening.

[0087] 34704-P-WO Tue / south 01.08.2025 The inventive method is suitable for all types of battery cells and represents an efficient and cost-effective manufacturing method.

[0088] In a further advantageous embodiment of the method according to the invention, the filling opening of the battery cell arranged in the receiving opening is formed by means of the laser beam which passes through the passage.

[0089] This measure has the advantage that, according to the inventive method, the battery cell is positioned in the receiving opening in a single device, and the filling opening, in the form of a hole, is first formed in the base of the battery cell housing by means of the laser beams passing through the laser-permeable aperture. In the subsequent steps, the battery is filled and sealed. This step further contributes to the efficiency of the inventive method.

[0090] In a further advantageous embodiment of the method according to the invention, steps b) and b.2) are provided after step b) and before step c): b) purging the process chamber and the battery cell arranged in the receiving opening with a gas, b.2) generating a vacuum in the process chamber and in the battery cell arranged in the receiving opening.

[0091] In a further advantageous embodiment of the process according to the invention, an inert gas, preferably nitrogen or argon, or SO2 is used as the gas in step bl).

[0092] In a further advantageous embodiment of the method according to the invention, the filling of the battery cell in step c) takes place several times alternately with the evacuation of the battery cell.

[0093] These steps can be repeated several times until all pores of the battery cell's interior are completely filled with electrolyte. This method is particularly suitable for electrolytes with low vapor pressure, such as organic electrolytes.

[0094] In a further advantageous embodiment of the method according to the invention, in step c) the line is positioned such that the filling opening is sealed against the interior of the process chamber by means of the line.

[0095] 34704-P-WO Tue / south 01.08.2025 This measure ensures a seal between the filling opening and the process chamber. An advantage of this design is that the electrolyte does not first enter the process chamber and then the battery cell. Instead, the electrolyte is filled directly into the battery cell via the line. This eliminates the need for an additional step in which the electrolyte solution must be removed from the process chamber.

[0096] In a further advantageous embodiment of the method according to the invention, the pressure in the process chamber is adjusted during step c) depending on the electrolytes used.

[0097] In battery cells with an SOj-based electrolyte, the pressure in the process chamber is at least 1 bar, preferably 3 bar, more preferably 5 bar and particularly preferably 7 bar.

[0098] In a further advantageous embodiment, an ablation welding pulse is performed using the laser before the actual welding process in order to laser away any crystallized electrolyte salt residues that may be present.

[0099] Further advantageous properties of the device and method according to the invention will become apparent from the following description of embodiments with reference to the drawings. The figures are not to scale, but rather schematic representations that only reveal the principle of the device and method according to the invention. In the figures, identical reference numerals denote identical or essentially equivalent elements or groups of elements. These include:

[0100] Fig. 1 shows a first embodiment of the device according to the invention as a sectional view (schematic representation) before the battery cell is placed,

[0101] Fig. 2 shows the representation of Fig. 1, with the battery cell placed in the receiving opening.

[0102] Fig. 3 shows a second embodiment of the device according to the invention as a sectional view (schematic representation), wherein the battery cell is placed in the receiving opening,

[0103] Fig. 4 shows discharge capacity as a function of the cycle count of four battery cells filled with SC-based electrolyte, where two of the cells are filled according to the

[0104] 34704-P-WO Tue / south 01.08.2025 State of the art and was carried out in two according to the inventive method.

[0105] Fig. 1 shows a first embodiment of the device (1) according to the invention. In the present embodiment, the device (1) has a process chamber (10). A receiving opening (11) is arranged in the lower part of the process chamber (10), in which a battery cell (2) can be at least partially received. The process chamber (10) can be designed to accommodate battery cells of various shapes. The battery cells can be, for example, round in the form of so-called wound cells (e.g., shapes 14500, 18650, 21700, 26650, 32600, or 46800) or rectangular (e.g., PHEV2 and BEV2 hardcase cell shapes) with stacked or flat-wound electrodes inside. The process chamber (10) can be adapted to battery cells of different sizes.

[0106] Furthermore, the process chamber (10) has an opening (13) suitable for accommodating at least one line (14) that transports gases, electrolyte, or the like into the process chamber (10) or directly into the battery cell (2). Gases can also be removed from the process chamber (10) and / or the battery cell (2) via the line (14) using a vacuum pump (not shown here). An optional upstream distribution unit, also not shown here, allows switching to the gases or electrolytes required for the respective process step or switching to the vacuum pump.

[0107] The housing (17) of the battery cell (2) has a filling opening (12), which is advantageously located in the base of the battery cell (2). The filling opening (12) has a diameter of 5000 pm, preferably 2500 pm, more preferably 1000 pm, still more preferably 750 pm, increasingly preferably 500 pm, and particularly preferably 250 pm.

[0108] The process chamber further comprises a passage (15) through which the laser beams can enter the process chamber (10). The passage (15) is closed with a laser-transparent material, preferably glass, as described in detail above. Optionally, the passage (15) can be protected from process gases or electrolytes within the process chamber (10) by means of a movable cover, not shown here. A laser welding device (8) is arranged above the passage (15).

[0109] 34704-P-WO Tue / south 01.08.2025 Fig. 2 shows the representation of Fig. 1, with the battery cell (2) and the line (14) being received in the process chamber. In this representation, the battery cell (2) is arranged in the receiving opening (11) such that it partially projects into the process chamber (10), so that the filling opening (12), in this embodiment located in the base of the battery cell (2), is situated in the process chamber (10).

[0110] The line (14) is movably mounted in the opening (13) so that it can be lowered into the process chamber (10) as needed. It can be lowered as far as the filling opening (12) of the battery cell (2), as shown in Fig. 2. The line (14) is designed such that it seals the filling opening (12) against the interior of the process chamber (10) when it comes into contact with the filling opening (12).

[0111] In this state, shown in Fig. 2, the battery cell (2) can be filled with a desired electrolyte. A suitable seal, e.g., at the tip of the line (14), allows the battery cell (2) to be filled through the filling opening (12) without large quantities of electrolyte entering the process chamber (10). This prevents, for example, contamination of the process chamber (10).

[0112] After filling, the filling opening (12) of the battery cell (2) is closed. In this embodiment, the line (14) is positioned so that it is near the filling opening (12). During this process step, the welding gas is supplied through the line (14). By lowering the line (14), the welding gas is directed to the filling opening (12) to be welded. The filling opening (12) is electrolyte-tightly welded by means of the laser beam (22). The laser beam (22) can be directed perpendicularly or at a suitable angle to the filling opening (12). Preferably, the laser beam (22) is not directed perpendicularly to the filling opening (12), but at a suitable angle, as this prevents potential damage to components such as electrodes or separators present in the battery cell (2).The laser beam (22) advantageously strikes the filling opening (12) of the battery cell (2) at an angle of preferably 85°, more preferably 80°, more preferably 75°, even more preferably 70°, and particularly preferably 65°, as shown schematically in Fig. 2.

[0113] The welding zone should preferably be twice the size of the filling opening (12). This ensures that sufficient material from the housing (17) of the battery cell (2) is available.

[0114] 34704-P-WO Tue / sü 01.08.2025 is used to close the filling opening (12). This method has the significant advantage that no additional material needs to be introduced into the process chamber (10) for welding the filling opening (12). The housing (17) is made of a material that can be laser-welded. For example, a housing (17) made of steel can be used.

[0115] Alternatively, additive welding is also possible by introducing the material for welding into the process chamber (10) near the filling opening (12) before the welding process.

[0116] Figure 3 shows a second embodiment of the device (1) according to the invention. The second embodiment has the same construction and the same elements as the first, with the exception of additional lines. In detail:

[0117] The second embodiment of the device according to the invention also has a process chamber (10) in which a receiving opening (11) is provided in the lower part, in which a battery cell (2) can be at least partially received. The process chamber (10) can be designed in the same way as in the first embodiment.

[0118] The process chamber (10) of the second embodiment also has a passage (15) through which the laser beams can pass. The passage (15) is designed in the same way as in the first embodiment.

[0119] Furthermore, the process chamber (10) of the second embodiment also has an opening (13) suitable for receiving at least one conduit (14). The opening (13) and the conduit (14) are designed identically to those of the first embodiment and have the same functions.

[0120] In addition to the opening (13) and the conduit (14), the process chamber (10) of the second embodiment has a further opening (18). A further conduit (19) can be received gas-tight in the opening (18). Furthermore, the conduit (19) is movably arranged in the opening (18). The process chamber (10) of the second embodiment also has a further opening (20). A further conduit (21) can be received gas-tight in the opening (20). Furthermore, the conduit (21) is movably arranged in the opening (20).

[0121] In contrast to the first embodiment, in which all gases and liquids can be transported one after the other via the single line (14), in the second embodiment the supply and / or removal of the gases and / or liquids can take place simultaneously.

[0122] 34704-P-WO Tue / south 01.08.2025 For example, the line (14) can be used to transport the electrolyte, and thus the battery cell (2) can be filled through the filling opening (12) via this line (14) after it has been lowered to the filling opening (12), in such a way that a seal against the interior of the process chamber (10) is ensured, so that no large quantities of electrolyte enter the process chamber (10). This prevents, for example, contamination of the process chamber (1).

[0123] Various gases, such as inert gases, SO2, or welding gas, can be fed into the process chamber (10) via the line (19). An optional upstream distribution unit, not shown here, allows switching to the gas required for the respective process step. The line (19) can be lowered into the process chamber (10) as needed. It can be lowered as far as the filling opening (12) of the battery cell (2). This is advantageous, for example, for laser welding, as it allows the welding gas to be delivered directly to the filling opening (12) being welded.

[0124] Simultaneously, the ambient pressure in the process chamber (10) can be adjusted via the additional line (21), so that electrolytes can be added and used within the process chamber (10) regardless of their respective prevailing vapor pressure, thus avoiding significant gas evolution. The line (21) can be connected to an external vacuum pump (23) to evacuate the process chamber (10) and the battery cell (2) as needed.

[0125] Another embodiment of the device according to the invention, which is not shown in the figures, provides that the process chamber (10) is designed to accommodate two or more battery cells. The filling of two or more battery cells can take place simultaneously or sequentially. Likewise, the sealing of two or more battery cells can take place simultaneously or sequentially.

[0126] The described embodiments are exemplary embodiments of the device according to the invention. The positions and number of the individual openings (13, 18, 20), lines (14, 19, 21), the receiving opening (11) and the passage (15) for the laser beams can vary and be designed in different ways.

[0127] The first embodiment according to Figs. 1 and 2 has one line (14), the second embodiment according to Fig. 3 has three separate lines (14, 19, 21). Two lines are also possible.

[0128] 34704-P-WO Tue / south 01.08.2025 Pipes or four or more pipes are used to transport gases and / or liquids into or out of the process chamber (10) and / or battery cell (2).

[0129] Upstream valves allow one or more lines to be used simultaneously for different gases and / or liquids. Two or more passages for laser beams and / or two or more laser welding devices can also be provided, for example, if the device contains two or more battery cells.

[0130] Storage tanks, buffer vessels, or backwash tanks can be connected to the line(s) and serve, for example, to supply electrolytes or to reduce pressure fluctuations. The exact fill quantity of electrolyte can also be determined outside the process chamber. In a preferred embodiment, a level control system ensures that a container is always filled and emptied to the same level, so that the volume of electrolyte for filling a battery cell remains constant. This method allows for very precise dosing quantities. In another preferred embodiment, the fill quantity is determined by a flow meter. As soon as the flow meter detects the set electrolyte flow rate, the electrolyte flow to the cell is interrupted. For example, a Coriolis mass flow meter can be used.This is a flow meter that measures the mass flow rate of liquids passing through it, and its measuring method is based on the Coriolis principle. Very precise dosing quantities can also be achieved with this method.

[0131] The filling time depends, among other things, on the flow rate. This can be accelerated, for example, by a pressure difference in the area of ​​the reservoir, resulting in faster filling of the battery cell.

[0132] The first embodiment of the inventive method for filling a battery cell with an electrolyte and subsequently sealing the battery cell with the above-described inventive device comprises the following steps: a) Positioning the battery cell in the receiving opening of the process chamber, such that the filling opening of the battery cell is arranged in the process chamber in a gas-tight and liquid-tight manner, b) Generating a vacuum in the process chamber and in the battery cell arranged in the receiving opening,

[0133] 34704-P-WO Tue / sü 01.08.2025 c) Filling the battery cell with the electrolyte using the line, which is arranged gas-tight in the opening and leads to the filling opening of the battery cell, d) Welding the filling opening of the battery cell using a laser beam that passes through the opening to the filling opening of the battery cell, e) Removing the sealed battery cell from the receiving opening.

[0134] The individual steps of the first procedure are described in more detail below.

[0135] Step a) Positioning the battery cell in the receiving opening of the process chamber (10) so that the filling opening (12) of the battery cell (2) is arranged in the process chamber (10) in a gas-tight and liquid-tight manner.

[0136] As described in detail above, the device according to the invention, in all embodiments, has a process chamber (10) with a receiving opening (11) into which a battery cell (2) can be inserted in a gas-tight and liquid-tight manner. The battery cell (2) is inserted at least partially into the process chamber (10) such that the filling opening (12) of the battery cell (2) is located within the process chamber (10). Gas and / or liquid exchange along the housing (17) of the battery cell (2) between the process chamber (10) and the environment is prevented by the seal, as can be seen particularly in Figures 2 and 3. Alternatively, the battery cell (2) is already filled with a suitable gas before being inserted into the process chamber (10). This can be, for example, an inert gas such as nitrogen or a process gas such as SO2.In a further alternative of the first embodiment of the method according to the invention, before the battery cell (2) is inserted, a battery cell barcode applied to the battery cell is scanned and / or the battery cell (2) is weighed and / or aligned for insertion into the process chamber (10), so that the filling opening (12) of the battery cell (2) is positioned such that the laser beams which pass through the passage (15) into the process chamber (10) meet the filling opening.

[0137] Step b) Creating a vacuum in the process chamber (10) and in the battery cell (2) arranged in the receiving opening (11).

[0138] To remove the gases contained in the process chamber (10) and the battery cell (2) placed in the receiving opening, e.g., air or inert gas such as nitrogen or process gas such as SO2, a vacuum is applied to the process chamber (10). This can be done via the line (14) at the

[0139] 34704-P-WO Tue / south 01.08.2025 first embodiment of the device according to the invention as shown in Fig. 1 and Fig. 2. In the second embodiment of the device according to the invention according to Fig. 3, the vacuum is generated via the line (21). The gases contained therein are extracted.

[0140] Optionally, the following steps can be carried out after step b): b) purging the process chamber (10) and the battery cell (2) arranged in the receiving opening (11) with a gas, b.2) generating a vacuum in the process chamber (10) and in the battery cell (2) arranged in the receiving opening (11).

[0141] In step bl), the process chamber (10) and the battery cell (2) arranged in the receiving opening (11) of the process chamber (10) are purged with a suitable gas, depending on the electrolyte used. For example, when filling the battery cell (2) with an SC-based electrolyte, SO2 is used as the purge gas. When filling with an organic electrolyte, purging is carried out with an inert gas, e.g., nitrogen.

[0142] Step b.2) serves to remove the purge gas from the process chamber (10) and the battery cell (2) and to facilitate the filling of the battery cell (2) with the electrolyte.

[0143] Step c) Filling the battery cell (2) with the electrolyte by means of the line (14) which is arranged gas-tight in the opening (13) and leads to the filling opening (12) of the battery cell (2).

[0144] The electrolyte for filling the battery cell (2) is introduced through the line (14). In a first advantageous embodiment of the method according to the invention, the line (14) is moved into the process chamber (10) up to the filling opening (12) of the battery cell (2). The line (14) is designed such that the filling opening (12) can be sealed against the process chamber (10). An advantage of this method is that the electrolyte does not first enter the process chamber (10) and then the battery cell (2), but is filled directly into the battery cell (2) through the line (14). This eliminates additional process steps in which the electrolyte solution has to be removed from the process chamber (10) and the chamber cleaned. Furthermore, different pressure conditions can be created in the battery cell (2) and in the process chamber (10) by sealing the filling opening (12) with the line.The pressure in the process chamber (10) can be adjusted to the electrolyte used. For example, a vacuum can be maintained or an overpressure set in the process chamber (10). This is also relevant when filling the battery cell.

[0145] 34704-P-WO Tue / south 01.08.2025 With an SO2-based electrolyte, maintaining an overpressure in the process chamber (10) has proven advantageous. The overpressure can be achieved, for example, by introducing an inert gas such as argon. In this case, the pressure in the process chamber should be at least 1 bar, preferably 3 bar, more preferably 5 bar, and particularly preferably 7 bar. After filling the battery cell via the line (14), it is lifted again and removed from the filling opening (12). Furthermore, when filling the battery cell (2) with SO2-based electrolyte, the remaining overpressure serves to prevent SO2 from outgassing from the battery cell.

[0146] Step d) Welding the filling opening (12) of the battery cell (2) by means of a laser beam which passes through the passage (15) to the filling opening (12) of the battery cell (2).

[0147] The laser for laser welding is located outside the process chamber (10), arranged such that the laser beam (22) can enter the process chamber (10) through the laser-transparent opening (15) and strike the filling opening (12). Optionally, the filling opening (12) can first be cleaned of any crystallized conductive salt by a laser pulse. The filling opening (12) is then tightly welded by means of the laser beam (22) so that no electrolyte can escape from the battery (2). In one embodiment of the method according to the invention, the process chamber (10) can be filled with the welding gas. Preferably, in the method according to the invention, the welding gas is supplied via the line (14), as shown in Figs. 1 and 2 in the first embodiment of the device according to the invention, or via the line (19), as shown in Fig. 1.Figure 3 shows the process chamber (10) moving to the filling opening (12) of the battery cell (2). This ensures that the welding gas exits precisely at the point where the laser welding takes place.

[0148] Step e) Remove the sealed battery cell from the receiving opening.

[0149] The battery cell (2), which is tightly sealed by laser welding, is removed from the device according to the invention.

[0150] The second embodiment of the method according to the invention comprises all steps a) to e) of the method according to the first embodiment, as described in detail above. In addition, the second embodiment of the method according to the invention has, after step a), a step a) in which the filling opening (12) of the

[0151] 34704-P-WO Tue / south 01.08.2025 The receiving opening (11) of the battery cell (2) is formed by means of the laser beam (22) which passes through the aperture (15). In detail:

[0152] In order for the battery cell (2) to be filled, it must have a filling opening (12). In the second embodiment of the method according to the invention, this filling opening (12) is only created when the battery cell (2) is already located in the process chamber (2) of the device according to the invention. After step a), during which the battery cell (2) is positioned in the receiving opening (11) of the process chamber (10) so that the location where the filling opening (12) of the battery cell (2) is to be produced is arranged in the process chamber (10) in a gas-tight and liquid-tight manner, the laser beam (22), which passes through the opening (15), strikes the filling opening (12) at an angle of preferably 85°, more preferably 80°, more preferably 75°, even more preferably 70°, and particularly preferably 65°. The filling opening (12) is thereby laser-cut in the desired shape, e.g., as a round hole.To protect the components inside the housing (17) of the battery cell (2), suitable measures can be taken, such as a spacer, preferably in ring form, being installed inside the housing (17) of the battery cell (2) around the filling opening (12). If the laser process releases minute particles from the housing (17), these can be extracted by means of a lowered line (14, 19, 21).

[0153] In order to describe the invention and the inventive method in more detail, examples of possible process steps for filling a battery cell with an SC-based electrolyte with an organic electrolyte are presented below.

[0154] Examples of possible process steps for filling a battery cell with an SO2-based electrolyte:

[0155] The barcode of the battery cell (2) is scanned, the battery cell (2) is aligned and weighed, the battery cell (2) is positioned in the receiving opening (11) of the process chamber (10), the battery cell (2) and the process chamber (10) are rinsed with SO2 via the line (14) or (19), the line (14) is subsequently lowered to the filling opening (12) in a sealing manner and an overpressure is created in the process chamber (10),

[0156] 34704-P-WO Tue / sü 01.08.2025 the battery cell (2) is filled with the SOj-based electrolyte and the corresponding line (14) is raised again, the line (14) or (19) is subsequently lowered to the filling opening (12) and the welding gas is allowed to flow out through the lowered line (14) or (19) at the filling opening (12) of the battery cell (2), the filling opening (12) of the battery cell (2) is closed by means of laser welding, the filled battery cell (2) is removed from the process chamber and weighed.

[0157] Examples of possible process steps for filling a battery cell with an organic electrolyte:

[0158] The barcode of the battery cell (2) is scanned, the battery cell (2) is aligned and weighed, the battery cell (2) is positioned in the receiving opening (11) of the process chamber (10), the battery cell (2) and the process chamber (10) are connected by means of the line (14) or

[0159] (21) evacuated to remove the gases, the battery cell (2) and the process chamber (10) are purged with inert gas via line (14) or (19), line (14) is subsequently lowered to the filling opening (12) and the battery cell (2) is filled with the organic electrolyte and the corresponding line (14) is raised again, line (14) or (19) is subsequently lowered to the filling opening (12) and the welding gas is allowed to flow out through the lowered line (14) or (19) at the filling opening (12) of the battery cell (2), the filling opening (12) of the battery cell (2) is closed by laser welding, the filled battery cell (2) is removed from the process chamber and weighed.

[0160] Experiment 1 - Filling with an electrolyte based on the state of the art and with the device according to the inventive method

[0161] In this experiment, two identical battery cells were filled with SC-based electrolyte. These were battery cells with a positive electrode containing lithium nickel manganese cobalt oxide as the active material and a negative electrode made of

[0162] 34704-P-WO Di / sü 01.08.2025 Carbon and with an SOj-based electrolyte with a lithium alkoxyaluminate conducting salt according to formula (I).

[0163] Two cells were filled and sealed using the previously standard open method. According to the state of the art, the electrolyte was poured directly into the opened battery cell. It was dripped onto the electrode winding / stack, and the cell was allowed to absorb the electrolyte. This dripping process continued until the electrolyte was visible above the electrode winding / stack. Due to the open nature of the process, this must be carried out in a dry room or under a protective gas atmosphere. Depending on the size of the battery cell, this process takes 20-60 minutes. Afterward, the battery cell is placed in a welding apparatus for sealing the lid assembly to the housing. This transfer must also be carried out in a dry room or under a protective gas atmosphere.

[0164] Two further cells were filled and sealed using the device and method according to the invention as described in the first embodiment.

[0165] To determine the discharge capacities, the four battery cells were charged with a current of 50 mA up to an upper potential of 4.3 volts. This upper potential was held until the charging current dropped to 40 mA. Discharge was then carried out with a current of 50 mA down to a discharge potential of 2.5 volts.

[0166] Fig. 4 shows the measurement curves of the four cells. The discharge capacity is shown as a function of the number of cycles. For better comparison, the discharge capacities have been normalized to 1.

[0167] The battery cells filled and sealed using the device and method according to the invention exhibit improved performance compared to cells filled and sealed according to the prior art. The latter show a decrease in the normalized discharge capacity to 0.55 or 0.75 after 600 cycles. The cells filled and sealed according to the invention still show a discharge capacity of 0.8 after 750 cycles. From this, it can be concluded that with the device and method according to the invention, the electrolyte is homogeneously distributed throughout the entire battery cell.

[0168] Experiment 2 - Investigation of the filling duration according to the prior art and with the device according to the inventive method

[0169] 34704-P-WO Tue / south 01.08.2025 TI

[0170] To compare the filling time of a battery cell, data on the filling of a conventional lithium-ion cell with organic electrolyte solution of size 2170 (wound cell with 21 mm diameter and 70 mm length) were compared with the corresponding data of the inventive method using the inventive device for filling a battery cell with SC-based electrolyte.

[0171] Table 1: Filling steps and duration

[0172] Filling the battery cells with SC-based electrolyte is about 20 times faster than filling a conventional lithium-ion battery with organic electrolyte solution.

[0173] 34704-P-WO Tue / south 01.08.2025 Experiment 3 - Investigation of the filling duration according to the prior art and with the device according to the method according to the invention

[0174] To compare the filling time of a battery cell, data on the filling of a lithium-ion cell according to the prior art with an SC-based electrolyte were compared with the corresponding data of the inventive method using the inventive device for filling a battery cell also with an SOj-based electrolyte.

[0175] Table 2: Filling steps and duration

[0176] 34704-P-WO Tue / south 01.08.2025

[0177] Filling the battery cells with SC-based electrolyte using the inventive method and device is about 20 times faster than filling using the prior art method.

[0178] 34704-P-WO Tue / south 01.08.2025

Claims

Claims 1. A device for filling a battery cell (2) with an electrolyte and subsequently sealing the battery cell (2), comprising a process chamber (10) having a receiving opening (11) in which the battery cell (2) is at least partially received such that a filling opening (12) of the battery cell (2) is arranged in the process chamber (10), and having an opening (13) suitable for receiving at least one line (14) for filling the battery cell (2), wherein the process chamber (10) with the received battery cell (2) and line (14) is gas-tight and liquid-tight, characterized in that the process chamber (10) has a passage (15) through which laser beams can pass to seal the filling opening (12) of the battery cell (2), so that the battery cell (2) at least partially received in the process chamber (10) can be filled with the electrolyte and subsequently sealed.

2. The device according to claim 1, characterized in that the passage (15) is formed from a laser beam-permeable material.

3. The device according to claim 2, characterized in that the laser beam-transparent material is selected from the group comprising: glass, diamond, sapphire, polymers and thin / thick film coatings and glass fiber reinforced plastics.

4. The device according to one of the preceding claims, characterized in that the laser beam strikes the filling opening (12) of the battery cell (2) at an angle of preferably 90°, more preferably 80°, more preferably 75°, still more preferably 70°, particularly preferably 65°. 34704-P-WO Tue / south 01.08.2025 5. The device according to one of the preceding claims, characterized in that the filling opening (12) is formed in a housing (17) of the battery cell (2).

6. The device according to one of the preceding claims, characterized in that the filling opening (12) is arranged in the bottom area of ​​the housing (17) of the battery cell (2).

7. The device according to one of the preceding claims, characterized in that the filling opening (12) has a diameter of 5000 pm, preferably 2500 pm, more preferably 1000 pm, still more preferably 750 pm, increasingly preferably 500 pm and particularly preferably 250 pm.

8. The device according to one of the preceding claims, characterized in that the line (14) is designed to be movable in such a way that it can be positioned so that the filling opening (12) is sealed against the interior of the process chamber (10) by means of the line (14).

9. The device according to one of the preceding claims, characterized in that the process chamber (10) has further openings (18, 20) in which further lines (19, 21) can be received in a gas-tight manner, wherein the lines (14, 19, 21) are movably arranged within the openings (13, 18, 20).

10. The device according to one of the preceding claims, characterized in that the electrolyte is an SOj-based electrolyte.

11. Method for filling a battery cell (2) with an electrolyte and subsequently sealing the battery cell (2) with a device according to one of claims 1 to 11, comprising the following steps: a) Positioning the battery cell (2) in the receiving opening (11) of the process chamber (10), so that the filling opening (12) of the battery cell (2) is arranged in the process chamber (10) in a gas-tight and liquid-tight manner, b) generating a vacuum in the process chamber (10) and in the receiving opening (11) arranged battery cell (2), c) filling the battery cell (2) with the electrolyte by means of the line (14) which is arranged gas-tight in the opening (13) and reaches the filling opening (12) of the battery cell (2), 34704-P-WO Tue / south 01.08.2025 d) Welding the filling opening (12) of the battery cell (2) by means of a laser beam which passes through the passage (15) to the filling opening (12) of the battery cell (2), e) Removing the sealed battery cell (2) from the receiving opening (11).

12. Method according to claim 11, characterized in that the filling opening (12) of the battery cell (2) arranged in the receiving opening (11) is formed by means of the laser beam which passes through the passage (15).

13. Method according to claim 11 or 12, characterized in that it comprises, after step b) and before step c), steps bl) and b.2): bl) purging the process chamber (10) and the battery cell (2) arranged in the receiving opening (11) with a gas, b.2) generating a vacuum in the process chamber (10) and in the battery cell (2) arranged in the receiving opening (11).

14. Method according to claim 13, characterized in that in step bl) an inert gas, preferably nitrogen or argon, or SO2 is used as the gas.

15. Method according to one of claims 11 to 14, characterized in that the filling of the battery cell (2) in step c) takes place several times alternately with the vacuuming of the battery cell (2).

16. Method according to one of claims 11 to 15, characterized in that in step c) the line (14) is positioned such that the filling opening (12) is sealed by means of the line (14) against the interior of the process chamber (10).

17. Method according to one of claims 11 to 16, characterized in that during step c) the pressure in the process chamber (10) is adjusted depending on the electrolytes used.

18. Method according to claim 17, characterized in that for an SO2-based electrolyte the pressure in the process chamber (10) is at least 1 bar, preferably 3 bar, more preferably 5 bar and particularly preferably 7 bar. 34704-P-WO Tue / south 01.08.2025

Images