FILLING DEVICE, ARRANGEMENT AND PROCEDURE

Abstract

A filling device (100) for filling an accumulator cell (500) with an electrolyte (E), comprising an eccentric screw pump (200) for metering the electrolyte (E), and a filling adapter (300) connected to the eccentric screw pump (200), which can be docked to the accumulator cell (500) for filling the accumulator cell (500) with the electrolyte (E) metered by the eccentric screw pump (200), wherein the filling adapter (300) has a switchable filling valve (312), an evacuation port (333) and a docking unit (323) for docking the filling adapter (300) to the accumulator cell (500), and wherein the filling adapter (300) can be docked to the accumulator cell (500) by means of a linear displacement of the docking unit (323) relative to the filling valve (312). an evacuation state (Z1) for evacuating the accumulator cell (500) using the evacuation port (333) into a filling state (Z2) for filling the accumulator cell (500) with the electrolyte (E) and vice versa.

Description

The present invention relates to a filling device for filling an accumulator cell with an electrolyte, an arrangement with an accumulator cell and such a filling device, and a method for filling an accumulator cell with an electrolyte.Efficient energy stores are of decisive importance for the increasing spread of electromobility. Lithium-ion batteries in particular play a central role here, since these have become established as technology for energy stores of this type. As energy stores, it is possible to use, for example, cylindrical accumulator cells, prismatic accumulator cells or so-called pouch cells. Cylindrical accumulator cells will be discussed below. However, the following embodiments are applicable to prismatic accumulator cells and pouch cells.Such a cylindrical accumulator cell can comprise a pot-shaped housing in which a cell body is accommodated. The housing is closed with the aid of a cover which has a filling opening for filling the rechargeable battery cell with an electrolyte. This filling opening is closed after the battery cell is filled with the electrolyte. The cell body comprises an anode and a cathode. A separator is placed between the anode and the cathode. The anode, the cathode and the separator are arranged alternately in layers. Specifically, the anode, the cathode, and the separator are spirally wound to form the cell body.The anode, the cathode and the separator are wetted or surrounded by the electrolyte, which enables lithium ions to be transported. The anode is the negative pole during a discharging operation of the accumulator cell. The anode is made of a copper foil having a thickness of about 8 μm to 18 μm, which is coated with an active material, for example graphite, and additives. The cathode forms a pole opposite to the anode and is made of an aluminum foil with a thickness of approximately 15 μm to 25 μm, which serves as a current collector. This aluminum foil is likewise coated with an active material and additives. Lithium nickel cobalt aluminum oxide (NCA), lithium cobalt oxide (LCO), and lithium nickel manganese cobalt oxide (NMC) are the most frequently used active materials for the cathode.The separator, which is a microporous membrane, isolates the anode and the cathode from each other and thus prevents direct contact and thus short circuit. At the same time, the separator must be permeable to lithium ions in order to enable ion transport. For the separator, polyethylene (PE) and / or polypropylene (PP) can be used, for example. These materials are preferably used because of their price and chemical stability.Between the anode and the cathode is the electrolyte, the primary function of which is to allow the transport of lithium ions from the anode to the cathode during discharge of the accumulator cell or vice versa from the cathode to the anode during charging of the accumulator cell. During the charging and discharging of the rechargeable battery cell, lithium ions are incorporated or removed from the cathode and the anode by an electrochemical reaction. Lithium ions move through the electrolyte from the anode to the cathode or vice versa. The anode material is oxidized and releases electrons which pass to the cathode via an external circuit.On the foils of the cathode and the anode, there is in each case a porous layer of the respective active material with the additives used. Pores of these layers typically have sizes in the nano- or micrometer range, which vary depending on the material used and the manufacturing process. There are open and closed pores. Open pores can be wetted by the electrolyte and thus participate in the electrochemical reaction. Closed pores, on the other hand, have a negative effect on the performance of the accumulator cell. The capillary effect draws the electrolyte into open pores.For a series production of accumulator cells with cycle times that are as short as possible, it is thus desirable to wet the anode, the cathode and the separator with the electrolyte as quickly and as completely as possible, so that no air bubbles or air-filled pores remain within the accumulator cell.The electrolyte is generally a multicomponent mixture which has as components a conducting salt and one or more solvents. The exact composition of the individual components of the electrolyte varies depending on the field of application of the rechargeable battery cell. The solvent may consist of a mixture of several different solvents. As the solvent, carbonates, esters and diesters, or the like, for example, may be used. Lithium hexafluorophosphate (LiPF 6) can be used, for example, as the conducting salt.The advantages of an electrolyte composed as above are that it is highly conductive and electrochemically stable and has good compatibility with conventional cell components of the accumulator cell. However, the electrolyte is thermally unstable and very sensitive to hydrolysis. Contact of the electrolyte with water may result in the formation of hydrogen fluoride. Its aqueous solution is known as hydrofluoric acid or hydrofluoric acid. This is highly corrosive and very harmful to health.The greatest challenge with regard to filling an accumulator cell as mentioned above with the electrolyte is accordingly that highly corrosive hydrogen fluoride is formed even when the electrolyte is in contact with traces of water. However, the formation of hydrogen fluoride when filling the accumulator cell is absolutely to be prevented.US 2021 / 0344090 A1 describes an electrolyte filling system using predetermined pressure / flow cycles. The electrolyte fill system allows at least one jelly roll assembly to be filled under vacuum.Against this background, it is an object of the present invention to provide an improved filling device for filling an accumulator cell with an electrolyte.Accordingly, a filling device for filling an accumulator cell with an electrolyte is proposed. The filling device comprises an eccentric screw pump for metering the electrolyte and a filling adapter connected to the eccentric screw pump, which can be docked to the accumulator cell for filling the accumulator cell with the electrolyte that can be metered by the eccentric screw pump, wherein the filling adapter has a switchable filling valve, an evacuation connection and a docking unit for docking the filling adapter to the accumulator cell, and wherein the filling adapter can be moved with the aid of a linear displacement of the docking unit relative to the filling valve from an evacuation state for evacuating the accumulator cell with the aid of the evacuation connection into a filling state for filling the accumulator cell with the electrolyte and vice versa. In this case, the evacuation connection is in fluid communication with an interior space of the accumulator cell in the evacuation state, wherein the evacuation connection is fluidically separated from the interior space in the filling state.Because the filling device has an eccentric screw pump for metering the electrolyte, the electrolyte can be metered into the accumulator cell with high precision and with controlled metering pressure. It is also possible to reverse a direction of rotation of a rotor of the eccentric screw pump to the end of the filling of the accumulator cell. This prevents the electrolyte from dripping at the filling valve. The battery cell is hereby not contaminated with the electrolyte on the outside when the docking unit is docked off from the battery cell. A prerequisite for this is that the eccentric screw pump is tight. This can be achieved by a suitable metering geometry of a rotor and a stator of the eccentric screw pump. The metering geometry is designed such that the eccentric screw pump meters or delivers only a small volume per revolution of the rotor. In particular, this can be achieved by a narrower or shorter pitch of the rotor and / or by a smaller eccentricity of the rotor.In addition, it is also possible with the aid of such an eccentric screw pump to meter the electrolyte directly into a reduced pressure prevailing within the accumulator cell. Hydrolysis of the electrolyte cannot occur because of the absence of water vapor. Due to the construction of the eccentric screw pump explained later, uncontrolled suction of the electrolyte into the accumulator cell due to the prevailing vacuum is also prevented. This is made possible in that between the rotor and the stator of the progressive cavity pump, mutually separate delivery spaces or delivery chambers are formed, which are filled with the electrolyte during operation of the filling device. The conveying spaces each form a tight system against vacuum and / or pressure. An undesired subsequent dripping of the electrolyte is thereby prevented.Because the filling adapter can be brought from the evacuation state into the filling state in which it is displaced relative to the filling valve, the rechargeable battery cell can be evacuated first with the aid of the filling adapter and then filled with the electrolyte. In other words, the docking unit is moved or moved in order to move the filling adapter from the evacuation state to the filling state.Volumetric filling can be realized with the eccentric screw pump. The advantage of such volumetric filling is that it is ensured volumetrically that a filling volume lies in a specific process window. The advantage here is that a filling rate can be kept under a burst threshold of the accumulator cell under pressure control, but with minimized cycle time. A metering end is reached either when a maximum target volume is reached or when a maximum pressure is reached, even at a minimum metering rate. The eccentric screw pump thus has the functions of volume-controlled and metering pressure-controlled.The accumulator cell can also be referred to as an accumulator or a secondary battery. Preferably, a plurality of such accumulator cells are combined to form an accumulator cell pack or accumulator pack. The accumulator cell can be, for example, a cylindrical accumulator cell. For example, the accumulator cell may have a diameter of 21 mm or 46 mm and a length of 70 mm, 80 mm, 90 mm or 120 mm. The battery cell may be, for example, a type 18650, 21700, 4680, 4690 or 46120. However, the aforementioned values for the diameter and the length can be selected as desired. The accumulator cell can also be a prismatic accumulator cell. In this case, the accumulator cell is cubical or cuboidal. However, it is assumed below that the accumulator cell is cylindrical.The accumulator cell preferably comprises a housing, within which a cell body having an anode and a cathode is arranged, between which a separator is placed. The anode, the cathode and the separator are spirally wound. In the case where the accumulator cell is a prismatic accumulator cell, the anode, the cathode and the separator are folded many times. The housing encloses an interior space within which the cell body is arranged. The electrolyte is metered into the interior in order to wet the anode, the cathode and the separator with the electrolyte.The accumulator cell further comprises a cover which closes the housing. The cover may be caulked or welded to the housing. A filling opening is preferably provided centrally on the cover, through which opening the electrolyte can be filled into the accumulator cell with the aid of the filling valve. For this purpose, the filling valve can be pushed into the filling opening in sections, in particular a nozzle needle of the filling valve. After filling, the filling opening is closed. For this purpose, the filling opening can be welded or caulked.The eccentric screw pump preferably has an eccentric screw pump device and a drive device for driving the eccentric screw pump device. The drive device comprises a drive unit and a transmission unit. The drive unit comprises, for example, an electric motor and a controller for controlling the electric motor. The drive unit drives the gear unit. The transmission unit can comprise a planetary gear, for example.The eccentric screw pump, in particular the eccentric screw pump device, preferably comprises a stator as mentioned above and a rotor as mentioned above rotatable within the stator. The rotor is in particular part of a rotor unit of the eccentric screw pump. The rotor unit is in particular coupled to the transmission unit of the drive device. The rotor unit can thus be driven with the aid of the drive device of the eccentric screw pump. The rotor unit is placed inside a pump housing of the eccentric screw pump, in particular of the eccentric screw pump device.The stator preferably has a tubular stator outer part and a stator inner part accommodated in the stator outer part. The stator outer part can be connected, for example, fixedly to the pump housing of the eccentric screw pump. The stator inner part is preferably elastically deformable. For this purpose, the stator inner part can be manufactured from an elastomer. The stator inner part has in particular a helical or helical inner geometry or inner contour. For this purpose, the stator inner part has, in particular, an aperture with a helical or helical inner geometry or inner contour. The stator inner part is connected to the stator outer part in a rotationally fixed manner. The stator inner part is replaceable in particular. The stator outer part can also be replaceable. The stator inner part is arranged in particular inside the stator outer part. The stator inner part can also be arranged at least in sections within the pump housing.The rotor unit preferably comprises a drive shaft which is driven by means of the drive device. In addition to the drive shaft, the rotor unit comprises the rotor, which has a worm-shaped or helical outer geometry or outer contour, which interacts with the worm-shaped or helical inner contour of the stator, in particular of the stator inner part of the stator, for metering the electrolyte. The rotor can be made of a metallic material, for example of stainless steel, or of a suitable plastic material.A flex shaft is arranged between the rotor and the drive shaft, which connects the rotor to the drive shaft. The flex shaft is here viewed along a longitudinal direction of the rotor unit, which is oriented from the drive shaft in the direction of the rotor and parallel to a symmetry or center axis of the rotor unit or of the eccentric screw pump device, placed between the drive shaft and the rotor.The flex shaft may also be referred to as a flex shaft. The flex shaft is preferably elastically deformable and enables an eccentric movement of the rotor in the stator, in particular in the stator inner part of the stator. The flex shaft serves to transmit torque from the drive shaft to the rotor. The flex shaft may be a wire cable which is coated or sheathed with a plastic material, for example.The flex shaft is connected to the drive shaft in a rotationally fixed manner and to the rotor in a rotationally fixed manner. When the rotor rotates in the stator, in particular in the stator inner part of the stator, the electrolyte to be metered is conveyed in the longitudinal direction away from the drive shaft according to the continuous piston principle by the interaction of the rotor with the stator, in particular with the stator inner part of the stator.In particular, the electrolyte is conveyed with the aid of the conveying spaces explained above from an inlet side of the stator, in particular of the stator inner part, in the direction of an outlet side of the stator, in particular of the stator inner part, according to the endless piston principle. On the outlet side, the eccentric screw pump is tight, since the delivery spaces each form self-contained units. A delivery volume per unit time is dependent on a rotational speed, a size, a pitch and a geometry of the rotor. With the eccentric screw pump, highly precise metering processes with a high repetition accuracy are thus possible. By reversing a direction of rotation of the rotor, the eccentric screw pump can also convey from the outlet side to the inlet side.The at least partially elastically deformable stator, in particular the stator inner part, preferably has a thread turn more than the rotor and twice the pitch length of the rotor. As a result, conveying spaces or conveying chambers remain between the stator, in particular the stator inner part, and the rotor rotating therein and additionally moving radially, which conveying spaces or conveying chambers move continuously from the inlet side to the outlet side. The electrolyte is located within these delivery spaces and is delivered from the inlet side of the stator to the outlet side thereof. Preferably, so many delivery spaces are provided that a so-called three-stage geometry of the dosing geometry is realized.The rotor is firmly connected to the drive shaft by means of the flex shaft. On the front side of the flex shaft, the rotor is arranged, which interacts with the stator, in particular with the stator inner part of the stator. The rotor is helical or helical. The fact that the rotor is "helical" or "helical" means in the present case in particular that the rotor has the previously mentioned helical or helical outer contour. The terms "helical" and "helical" are in the present case arbitrarily interchangeable. During operation of the eccentric screw pump, the rotor interacts with the stator, which in particular has the aforementioned aperture on or in the stator inner part in which the rotor is arranged.A "flex shaft" is understood in the present case to mean a shaft, in particular generally a component, which permits an eccentric movement of the rotor with respect to the drive shaft. For this purpose, the flex shaft can have, for example, a joint, in particular a universal joint or a cardan joint, or a plurality of joints. The flex shaft may also be referred to as a flex shaft or a propeller shaft. Particularly preferably, however, the flex shaft itself is elastically deformable. However, it is not absolutely necessary for the flex shaft itself to be flexibly deformable.The flex shaft can also be a bending rod, in particular a plastic bending rod, or can be referred to as such. In this case, the flex shaft may be made of, for example, a polyetheretherketone (PEEK), polyethylene (PE), or the like. In this case, the entire rotor unit can be manufactured as a single-use component from a plastic material. Particularly preferably, however, the flex shaft is made of a steel cable, in particular a plastic-coated steel cable. In particular, the steel cable can be elastomer-coated. Examples of elastomers which can be used are fluororubbers (FKM) or perfluoro rubbers (FFKM).The eccentric screw pump and the filling adapter together form the filling device. However, this does not exclude that the filling device has further assemblies or components. In particular, the filling adapter can be released from the eccentric screw pump. In other words, the filling adapter is detachably connected to the eccentric screw pump. For this purpose, the filling adapter can have, for example, a union nut or a threaded sleeve, with the aid of which the filling adapter can be detachably connected to the eccentric screw pump.The fact that the filling adapter is "dockable" to the rechargeable battery cell is to be understood in the present case in particular as meaning that the filling adapter can be connected to the rechargeable battery cell. Such a "connection" of the filling adapter to the accumulator cell can be understood in the present case to mean that the filling adapter is pressed against the aforementioned cover of the accumulator cell and seals it in a fluid-tight manner with respect to the cover. The filling adapter can be "docked" from the rechargeable battery cell in that the filling adapter is lifted off the cover of the rechargeable battery cell again.With the aid of the filling valve, the electrolyte that can be metered by the eccentric screw pump can be filled into the accumulator cell. The fact that the filling valve is "switchable" is to be understood in the present case in particular as meaning that the filling valve can be moved from a closed position or a closed state into an open position or an open state and vice versa. In other words, the filling valve can preferably be either opened or closed as desired. For this purpose, the filling valve can have a valve body, in particular a linearly displaceable valve body. The valve body is arranged in particular within a filling valve housing of the filling valve.With the aid of the evacuation connection, a vacuum or a reduced pressure can be applied to the accumulator cell. For example, a reduced pressure of up to 50 mbar absolute can be applied before the accumulator cell is filled with the electrolyte. The evacuation port is preferably attached to the docking unit. A vacuum line is connected to the evacuation connection, leading to a vacuum pump. A valve and a pressure sensor are connected in the vacuum line. With the aid of the valve, the evacuation connection can be disconnected from the vacuum pump. With the aid of the valve, it is also possible to vent the evacuation connection to the atmosphere. The pressure sensor can be used to detect or monitor the applied negative pressure.The docking unit can be linearly displaced with respect to the filling valve, in particular with respect to the previously mentioned filling valve housing, in order to move the docking unit from the evacuation state to the filling state. The evacuation state and the filling state differ from one another in that the docking unit is pushed further onto the filling valve in the filling state than in the evacuation state. That is, the filling adapter can be moved from the evacuation state into the filling state by pressing it against the cover of the accumulator cell. As a result, the docking unit is displaced with respect to the filling valve.When the docking unit abuts against the cover of the accumulator cell, the evacuation state differs from the filling state in particular in that the evacuation connection is in fluid communication with the interior of the accumulator cell in the evacuation state, whereas the evacuation connection is fluidically separated from the interior in the filling state.The filling adapter preferably comprises a distributor block through which the electrolyte is passed during operation of the filling device. Within the distributor block, the electrolyte can be diverted or deflected through 90° during operation of the filling device. The filling valve, in particular the filling valve housing, is mounted on the distributor block. The docking unit is in turn mounted linearly displaceably on the filling valve. In other words, the distributor block carries the filling valve, wherein the filling valve carries the docking unit. The filling adapter is connected to the eccentric screw pump. For this purpose, the previously mentioned threaded sleeve can be rotatably mounted on the distributor block.In order to move the filling adapter from the evacuation state into the metering state, the filling device, in particular the filling adapter, can be moved towards the accumulator cell. For this purpose, the eccentric screw pump can be mounted, for example, on a linear spindle unit, with the aid of which the eccentric screw pump together with the filling adapter can be moved linearly. Alternatively, the accumulator cell can also be moved to the filling adapter. This may be advantageous due to the lower mass to be moved. In order to be able to fill a plurality of accumulator cells in short succession, these can be accommodated, for example, in holders which are mounted on a rotary table which is rotated further in each case after the filling of an accumulator cell.The filling device can furthermore have a box-shaped safety cell, within which the eccentric screw pump, the filling adapter, the accumulator cell and, if appropriate, a linear spindle unit as mentioned above are arranged. Within the safety cell, controlled conditions, such as a defined gas pressure, a defined air humidity and / or a defined temperature, may prevail. In particular, the safety cell can be flushed with dried air in order to prevent contact of the electrolyte with water vapor in the event of possible escape of the electrolyte. Furthermore, the safety cell prevents an operator or user of the filling device from coming into contact with the moving eccentric screw pump.According to one embodiment, the docking unit is spring-biased by means of a spring element in the direction of the evacuation state.The spring element is in particular a compression spring. The spring element can be a cylinder spring or a disk spring pack. In particular, the spring element is arranged between the filling valve housing of the filling valve and the docking unit. If the docking unit is moved from the evacuation state into the filling state, the docking unit moves towards the filling valve housing, in particular towards a flange section of the filling valve housing, so that the spring element is compressed. For this purpose, a force is applied to the docking unit. If this force no longer acts on the docking unit, the docking unit moves automatically or automatically from the filling state back into the evacuation state.According to a further embodiment, the filling valve is arranged at least in sections within the docking unit.In particular, the filling valve is passed at least in sections through the docking unit. The docking unit can have, for example, a threaded sleeve into which a nozzle insert of the docking unit is screwed. The nozzle insert can be placed on the accumulator cell. In this case, an end face of the nozzle insert contacts the cover of the accumulator cell. A sealing element, in particular in the form of an O-ring, is mounted on the end face in order to be able to seal the nozzle insert in a fluid-tight manner with respect to the cover of the accumulator cell. The filling valve, in particular the filling valve housing, is passed through the threaded sleeve and the nozzle insert. In particular, the threaded sleeve bears against a securing ring which is preferably accommodated in an annular groove which is attached on the outside of the filling valve housing. The spring element presses in particular the docking unit against the securing ring. In order to move the docking unit from the evacuation state into the filling state, the docking unit is lifted from the securing ring against a spring force of the spring element. The spring element is thereby compressed. The spring element biases the docking unit against the aforementioned retaining ring.According to a further embodiment, the filling valve has a filling valve housing and a valve body arranged within the filling valve housing.The filling adapter preferably comprises the aforementioned distributor block, on which the filling valve housing is mounted. A valve bore is passed through the filling valve housing, within which the valve body is arranged. The distributor block can also have a valve bore. The valve body is also arranged within this valve bore. The two valve bores can be arranged coaxially with respect to one another. The valve body is in particular needle-shaped. The valve body can therefore also be referred to as a valve needle. The valve body is placed inside the filling valve housing, in particular inside a valve section of the filling valve housing, and inside the distributor block.According to a further embodiment, the filling valve has an actuating element which is configured to linearly displace the valve body within the filling valve housing in order to move the filling valve in the filling state from a closed state to an open state and vice versa.In other words, the valve body is displaced linearly with respect to the filling valve housing with the aid of the actuating element. The closed state may also be referred to as a closed position. The open state can also be referred to as an open position. The adjusting element is in particular a pneumatic cylinder which has a piston which can be pressurized. The piston is connected to the valve body, for example screwed to the latter. Alternatively, the piston is integrated into the valve body. The adjusting element is mounted in particular on the distributor block. The adjusting element is in particular part of a pneumatic system, with the aid of which the piston can be pressurized. The adjusting element is assigned a valve, with the aid of which it is possible to switch selectively either to the closed state or to the open state. The adjusting element can alternatively also have an electric motor or an electromagnet for displacing the valve body.According to a further embodiment, the valve body has a fluid-permeable valve body head, wherein the valve body is mounted in the filling valve housing in a linearly displaceable manner with the aid of the valve body head.In particular, the valve body head abuts on the inside of the valve bore of the filling valve housing and slides off on the inside thereof in order to move the filling valve from the closed state to the open state and vice versa. In addition to the valve body head, the valve body preferably comprises a valve body shaft which has a smaller diameter than the valve body head. The valve body shaft thus does not contact an inner surface of the valve bore. The fact that the valve body head is "fluid-permeable" is to be understood in the present case in particular as meaning that the electrolyte can flow through the valve body head. For this purpose, the valve body head can have, for example, flow openings, bores, cut-outs, channels or the like. Alternatively, the valve body head can be made at least in sections from a porous material. Porous, in particular open-pore, materials used are, for example, metal foams or ceramic foams.According to a further embodiment, the valve body head has contact sections, with the aid of which the valve body head is mounted in the filling valve housing in a linearly displaceable manner, and throughflow openings through which the electrolyte can flow.The valve body head rests in particular only with the aid of its contact sections on the filling valve housing, in particular on the inner surface of the valve bore. The flow openings are arranged between the contact sections. The contact sections and the flow openings are arranged alternately, so that a flow opening is always arranged between two contact sections and a contact section is always arranged between two flow openings. For example, four contact sections and four flow openings are provided. However, this number can be selected as desired. In addition, a geometry or shape of the contact sections and / or of the flow openings can be selected as desired. For example, three contact sections and three flow openings can also be provided. The flow openings can be designed, for example, as flattened portions attached to the valve body head.According to a further embodiment, the filling valve housing has a tubular nozzle needle which projects beyond an end face of the filling valve housing.In the filling state of the filling adapter, the end face preferably abuts the cover of the accumulator cell, so that the tubular nozzle needle protrudes into the filling opening of the accumulator cell. This simplifies the metering of the electrolyte. A sealing element, for example an O-ring, is preferably attached to the end face of the filling valve housing in order to seal the end face in a fluid-tight manner with respect to the cover of the accumulator cell.According to a further embodiment, the valve body has a needle section which can be arranged within the nozzle needle, wherein a sealing element for the fluid-tight sealing of the valve body with respect to a valve seat of the filling valve housing has on the needle section.In particular, the needle section extends at the front side out of the valve body head. The valve body head has in particular a frustoconical or conical end side which points toward the valve seat of the filling valve housing. The valve seat is preferably frustoconical or conical. In the closed state of the filling valve, the sealing element, which can be an O-ring, for example, is pressed between the valve seat and the end face of the valve body head in order to close the filling valve in a fluid-tight manner. In the closed state of the filling valve, the needle section is arranged inside the nozzle needle, whereas in the open state the needle section is arranged outside the nozzle needle.According to a further embodiment, the filling adapter has a metering pressure sensor for detecting a metering pressure of the electrolyte, wherein the metering pressure sensor projects into a valve bore of the filling valve, and wherein the valve body is arranged within the valve bore.As mentioned above, both the distributor block and the filling valve housing can each have a valve bore. Preferably, the metering pressure sensor is mounted on the manifold block and protrudes into the valve bore of the manifold block. With the aid of the metering pressure sensor, the electrolyte can be metered into the accumulator cell under metering pressure regulation. For this purpose, the drive unit can be actuated, for example, on the basis of sensor signals of the metering pressure sensor, in order to adjust a metering speed of the eccentric screw pump, for example. The metering speed can be influenced by a change in rotational speed.Furthermore, an arrangement with an accumulator cell and such a filling device is proposed, wherein the docking unit rests against a cover of the accumulator cell both in the evacuation state and in the filling state, wherein the evacuation connection is in fluid communication with an interior of the accumulator cell in the evacuation state, and wherein the evacuation connection is fluidically separated from the interior in the filling state.By moving the filling adapter from the evacuation state into the filling state, the interior of the accumulator cell is thus fluidically separated from the evacuation connection. However, the negative pressure remains present in the accumulator cell, so that metering can be effected by means of the progressive cavity pump into the interior of the accumulator cell which is under negative pressure. In the evacuation state, the docking unit is sealed at the end side with the aid of the sealing element of the nozzle insert in a fluid-tight manner with respect to the cover of the accumulator cell. In the metering state, the filling valve is additionally sealed off on its end side likewise in a fluid-tight manner with respect to the cover of the accumulator cell with the aid of the sealing element mounted there.Furthermore, a method for filling an accumulator cell with an electrolyte is proposed. The method is carried out with the aid of a filling device as mentioned above. The method comprises the following steps: a) evacuating the accumulator cell in order to generate a negative pressure within the accumulator cell, and b) metering the electrolyte into the accumulator cell with the aid of an eccentric screw pump, wherein the electrolyte is metered into the negative pressure.Because the electrolyte is metered into the reduced pressure, foaming of the electrolyte is prevented in particular during the metering into the accumulator cell. Steps a) and b) may be performed sequentially. Furthermore, it is also possible to carry out steps a) and b) alternately, as will be explained in the following. In the present case, "evacuation" is to be understood in particular as meaning that a vacuum or a reduced pressure is applied to the accumulator cell. For example, a reduced pressure of 50 mbar absolute can be achieved. However, this aforementioned value is to be understood as merely exemplary. During step a), in particular, the interior of the housing of the accumulator cell is evacuated.According to one embodiment, steps a) and b) are performed alternately.In other words, the accumulator cell is evacuated in order subsequently to meter in the electrolyte. The accumulator cell is then evacuated again and the electrolyte is metered in again. Thus, a partial amount of electrolyte is metered. Furthermore, by changing between steps a) and b), a so-called "pressure massage" of the electrolyte is possible. Air bubbles within the accumulator cell are thereby reliably expelled. Furthermore, foaming of the electrolyte is prevented. In order to carry out steps a) and b) alternately, after step b) the filling valve is first closed. The filling adapter is then moved from the filling state to the evacuation state. The accumulator cell can then be evacuated again. The filling adapter is then brought back into the filling state and the filling valve is opened again. This sequence can be repeated as many times as desired. A pressure massage is also possible by varying the metering pressure of the progressive cavity pump during the filling of the accumulator cell with the electrolyte. For example, the electrolyte is metered into the accumulator cell under pressure control up to an exemplary metering pressure of 3 bar. The eccentric screw pump then rotates back-in other words a reversal of the direction of rotation of the rotor-until a metering pressure of, for example, 1.5 bar is reached. The metering pressure is then increased again to, for example, 2 bar and then reduced to, for example, 1.5 bar and then regulated to a metering end. The aforementioned procedures for pressure massage can also be combined with one another.According to a further embodiment, step b) is carried out under pressure regulation.For this purpose, a metering pressure of the electrolyte is detected and monitored with the aid of the pressure sensor. In particular, step b) is carried out under metering pressure regulation. The metering speed of the eccentric screw pump can be adapted as a function of the metering pressure, so that the metering can be carried out under pressure regulation, in particular under metering pressure regulation. The metering pressure can be adjusted as desired during step b). In particular, any desired metering pressure profiles can be driven. Particularly preferably, the previously explained pressure massage can be carried out during or with the aid of step b).The method is carried out with the aid of a filling device as explained above, wherein the filling adapter is moved from the evacuation state into the filling state in that the docking unit is pressed against a cover of the accumulator cell or vice versa, whereby the docking unit is displaced relative to the filling valve.For this purpose, as mentioned above, either the filling device can be displaced relative to the accumulator cell or the accumulator cell can be displaced relative to the filling device. For this purpose, for example, a linear spindle unit as mentioned above can be used, on which the eccentric screw pump together with the filling adapter is mounted.The embodiments and features described for the proposed filling device apply correspondingly and vice versa to the proposed arrangement and to the proposed method."An" is not necessarily to be understood as limiting to exactly one element. Rather, a plurality of elements, such as two, three or more, can also be provided. Any other numerical word used here is also not to be understood as being limited to exactly the stated number of elements. Instead, numerical deviations upwards and downwards are possible unless indicated to the contrary.Further possible implementations of the filling device, the arrangement and / or the method also comprise combinations, not explicitly mentioned, of features or embodiments described above or below with respect to the exemplary embodiments. In this case, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic shape of the filling device, the arrangement and / or the method.Further advantageous embodiments and aspects of the filling device, the arrangement and / or the method are the subject matter of the dependent claims and of the exemplary embodiments of the filling device, the arrangement and / or the method described below. The filling device, the arrangement and / or the method will be explained in more detail below on the basis of preferred embodiments with reference to the enclosed figures. FIG. 1 shows a schematic perspective view of an embodiment of a filling device; FIG. 2 shows a schematic sectional view of the filling device according to FIG. 1 ; FIG. 3 shows the detailed view III according to FIG. 2 ; FIG. 4 shows a schematic perspective view of an embodiment of a filling adapter for the filling device according to FIG. 1 ; FIG. 5 shows a schematic sectional view of the filling adapter according to FIG. 4 ; FIG. 6 shows a schematic view of an embodiment of a valve body for the filling adapter according to FIG. 4 ; FIG. 7 shows a schematic sectional view of the valve body along the section line VII-VII of FIG. 6 ; FIG. 8 shows a schematic perspective view of an embodiment of an arrangement comprising the filling device according to FIG. 1 ; FIG. 9 shows a schematic side view of an embodiment of a holder for the filling device according to FIG. 1 ; FIG. 10 shows a schematic sectional view of the holder according to the section line X-X of FIG. 9 ; FIG. 11 shows a schematic perspective view of an embodiment of a linear spindle unit for the filling device according to FIG. 1 ; FIG. 12 shows a schematic perspective view of an embodiment of a valve and sensor arrangement for the filling device according to FIG. 1 ; FIG. 13 shows a schematic sectional view of an embodiment of an accumulator cell; FIG. 14 shows a schematic view of an embodiment of a cell body for the accumulator cell according to FIG. 13 ; FIG. 15 shows a schematic block diagram of an embodiment of a procedure for filling the rechargeable battery cell according to FIG. 13 with an electrolyte; FIG. 16 shows a schematic detailed sectional view of the arrangement according to FIG. 8 ; FIG. 17 shows a further schematic detailed sectional view of the arrangement according to FIG. 8 ; FIG. 18 shows a further schematic detailed sectional view of the arrangement according to FIG. 8 ; FIG. 19 shows a further schematic detailed sectional view of the arrangement according to FIG. 8 ; FIG. 20 shows a further schematic detailed sectional view of the arrangement according to FIG. 8 ; FIG. 21 shows a schematic diagram of an embodiment of the procedure according to FIG. 15 ; and FIG. 22 shows a schematic block diagram of an embodiment of a method for filling the accumulator cell of the accumulator cell according to FIG. 13 with an electrolyte.In the figures, identical or functionally identical elements have been provided with the same reference numerals, unless otherwise indicated.FIG. 1 shows a schematic perspective view of an embodiment of a filling device 100. FIG. 2 shows a schematic sectional view of the filling device 100. FIG. 3 shows the detailed view III according to FIG. 2 ; FIGS. 1, 2 to 3 are simultaneously referred to below.With the aid of the filling device 100, an electrolyte E can be metered in. The electrolyte E can also be referred to as an electrolyte liquid or as an electrolyte mixture. A primary function of the electrolyte E is to transport charge from an anode to a cathode of an accumulator cell (not shown) or vice versa.The electrolyte E is a multicomponent mixture which comprises as components a conducting salt and one or more solvents. The exact composition of the individual components of the electrolyte E varies depending on the field of application of the rechargeable battery cell. The solvent may consist of a mixture of several different solvents. As the solvent, for example, carbonates, esters and diesters or the like can be used. Lithium hexafluorophosphate (LiPF 6) can be used, for example, as the conducting salt. The electrolyte E has, for example, a density of 1.1 g / cm 3 to 1.3 g / cm 3. The dynamic viscosity of the electrolyte E is preferably in the range from 1 mPas to 27.5 mPas.The advantages of an electrolyte E composed as explained above are that it is highly conductive and electrochemically stable and has good compatibility with other cell components of the rechargeable battery cell. However, the electrolyte E is thermally unstable, in particular thermal decomposition of the electrolyte E can occur starting at about 70° C., and is very sensitive to hydrolysis. Contact of the electrolyte E with water may result in the formation of hydrogen fluoride. Its aqueous solution is known as hydrofluoric acid or hydrofluoric acid. This is highly corrosive and very harmful to health.The greatest challenge with regard to filling an accumulator cell as mentioned above with the electrolyte E is accordingly that highly corrosive hydrogen fluoride is formed even when the electrolyte E is in contact with traces of water. This challenge can be overcome with the filling device 100, as will be explained below.In the following, the structural design of the filling device 100 for dosing the electrolyte E is explained first with reference to FIGS. 1, 2 to 3. The filling device 100 has an eccentric screw pump 200 and a filling adapter 300. The filling adapter 300 is detachably connected to the eccentric screw pump 200 and can therefore be exchanged. Furthermore, it is possible to connect the filling adapter 300 selectively to different eccentric screw pumps 200.The filling device 100 further comprises a cartridge 101 (FIG. 1 ). The cartridge 101 can contain, for example, a volume of 360 ml of the electrolyte E to be metered. The cartridge 101 is replaceable. A capacitive sensor unit 102 is attached, in particular clamped, to the cartridge 101. The capacitive sensor unit 102 comprises a holder and a capacitive sensor which is held by the holder. With the aid of the capacitive sensor unit 102, it is possible, for example, to detect a minimum fill level of the electrolyte E in the cartridge 101. For example, the capacitive sensor unit 102 can output a sensor signal when the minimum fill level is reached. An optical and / or acoustic signal can then be output to a user of the filling device 100, for example, in such a way that the user is requested to replace the cartridge 101.The cartridge 101 is connected to an adapter 105 by means of an adapter nipple 103 and a reducer 104. The adapter 105 is connected to an elbow 107 by means of a joint clamp 106. The curved piece 107 is connected to the eccentric screw pump 200 with the aid of a further joint clamp 108, as will be explained later. The articulated clamps 106, 108 are designed as quick-action closures and can be manually released or opened by the user.The eccentric screw pump 200 itself comprises a drive device 201 with a drive unit 202 and a gear unit 203. The drive unit 202 comprises, for example, an electric motor and a controller for controlling the electric motor. The drive unit 202 drives the gear unit 203. The transmission unit 203 may include, for example, a planetary gear.In addition to the drive device 201, the eccentric screw pump 200 comprises an eccentric screw pump device 204, which is shown in detail in FIG. 3. The eccentric screw pump device 204 is driven by the drive device 201 for metering the electrolyte E. The eccentric screw pump 200 or the eccentric screw pump device 204 is assigned a symmetry or center axis 205, with respect to which the eccentric screw pump device 204 can be constructed substantially rotationally symmetrically.The drive device 201, in particular the gear unit 203, is coupled to a bearing shaft 208 of the eccentric screw pump device 204 with the aid of a shaft coupling 206 and a coupling star 207. The coupling star 207 is made of a heat-insulating material, for example of a plastic material or of rubber. The coupling star 207 is star-shaped and can have, for example, four arms. The coupling star 207 provides for a thermal decoupling of the bearing shaft 208 from the shaft coupling 206 and vice versa. The bearing shaft 208 is rotatably mounted on or in a bearing housing 210 with the aid of a bearing 209, for example in the form of a rolling bearing. The bearing housing 210 may be made of a metallic material.Connected to the bearing shaft 208 is a rotor unit 211 of the eccentric screw pump 200 or of the eccentric screw pump device 204. The rotor unit 211 can also be referred to as a rotor train. The rotor unit 211 has a drive shaft 212 which is accommodated at least in sections in the bearing shaft 208 and is connected to the bearing shaft 208 in a rotationally fixed manner with the aid of a connecting element 213, for example in the form of a screw. The drive shaft 212 can be made of a metallic material. The central axis 205 may be associated with the rotor unit 211.In addition to the drive shaft 212, the rotor unit 211 comprises a rotor 214 which is helical or helical and thus comprises a helical or helical outer contour. The rotor 214 may be made of a metallic material, for example stainless steel, or a suitable plastic material.A flexible shaft 215 is arranged between the rotor 214 and the drive shaft 212 and connects the rotor 214 to the drive shaft 212 in a rotationally fixed manner. In this case, the flex shaft 215 is placed between the drive shaft 212 and the rotor 214 as viewed along a longitudinal direction L of the rotor unit 211, which is oriented from the drive shaft 212 in the direction of the rotor 214 and parallel to the central axis 205. The flex shaft 215 may also be referred to as a flex shaft. The flex shaft 215 is preferably elastically deformable and allows eccentric movement of the rotor 214. The flex shaft 215 is used to transmit torque from the drive shaft 212 to the rotor 214.The flex shaft 215 may be a wire rope provided with, for example, a jacket 216. The jacket 216 may be a plastic material or an elastomer. For example, the jacket 216 may be made of rubber. The flex shaft 215 may also be referred to as a flex shaft. The flex shaft 215 fixedly connects the drive shaft 212 to the rotor 214.The flex shaft 215 can alternatively have a joint, in particular a universal joint or a cardan joint, or a plurality of joints. This hinge or hinges allow the aforementioned eccentric movement of the rotor 214. The flex shaft 215 can accordingly also be referred to as a propeller shaft. The flex shaft 215 may also be a bending rod, in particular a plastic bending rod, or may be referred to as such. In this case, the flex shaft 215 may be made of, for example, polyetheretherketone (PEEK), polyethylene (PE), or the like. In the case that the flex shaft 215 is a plastic bending rod, the entire rotor unit 211 can be manufactured from a plastic material, for example as a plastic injection-molded component. In this case, the rotor unit 211 may be a disposable product.The eccentric screw pump 200 or the eccentric screw pump device 204 furthermore comprises a pump housing 217 through which the rotor unit 211 runs centrally. The pump housing 217 can be manufactured from a metallic material. The pump housing 217 can be constructed at least in sections rotationally symmetrically to the central axis 205.The pump housing 217 encloses a bore-shaped feed region 218, through which the electrolyte E is fed to the rotor 214. The flex shaft 215 extends along the central axis 205 through the feed region 218. The pump housing 217 has a feed flange 219 oriented perpendicularly to the central axis 205, which leads into the feed region 218. Through the supply flange 219, the electrolyte E is supplied to the rotor unit 211 perpendicularly to the central axis 205. A flanged pipe 220 is attached to the supply flange 219. For this purpose, a clamping connection or a screw connection can be provided. The aforementioned curved piece 107 can be connected to the flanged tube 220 by means of the joint clamp 108.In addition to the pump housing 217, the eccentric screw pump device 204 comprises an upper housing part 221. The upper housing part 221 can be manufactured from a metallic material. The upper housing part 221 is connected, for example screwed, to the pump housing 217. A plurality of sealing elements 222, 223 can be accommodated in the upper housing part 221. The sealing elements 222, 223 can have sealing lips which abut on the rotor unit 211.In particular, the sealing elements 222, 223 bear against a tubular protective sleeve 224 in which the drive shaft 212 is accommodated. The protective sleeve 224 is made of a metallic material, for example, of stainless steel. The protective sleeve 224 may also be made of hard chrome plated (HVC) stainless steel or a ceramic. The protective sleeve 224 is slid onto the drive shaft 212. The protective sleeve 224 is replaceable. Thus, the protective sleeve 224 can be replaced when it is worn out. The protective sleeve 224 can therefore also be referred to as a wear protection sleeve. The protective sleeve 224 is constructed rotationally symmetrically to the central axis 205.The bearing housing 210 is accommodated in the upper housing part 221 at least in sections. The bearing housing 210 is firmly connected to the upper housing part 221. Screwed onto the bearing housing 210 is furthermore a union nut or a threaded sleeve 225, with the aid of which a drive housing 226, within which the shaft coupling 206 is arranged, is connected to the upper housing part 221. The drive housing 226 may be made of a metallic material.The threaded sleeve 225 is rotatably mounted on the drive housing 226. The drive housing 226 together with the threaded sleeve 225 can thus be separated from the eccentric screw pump device 204. The drive housing 226 is connected, for example screwed, to the transmission unit 203. It is thus possible to connect the drive device 201 and the eccentric screw pump device 204 to one another and to disconnect them from one another with the aid of the threaded sleeve 225. This enables simple assembly and disassembly of the eccentric screw pump 200. This is advantageous, for example, for cleaning purposes.An at least partially elastically deformable stator 227 of the eccentric screw pump device 204 is attached to the pump housing 217. The stator 227 may also be referred to as a stator housing. Accordingly, in the present case, the terms "stator" and "stator housing" can be interchanged with one another as desired. The stator 227 has a tubular stator outer part 228 and a stator inner part 229 accommodated in the stator outer part 228. The stator outer part 228 can also be referred to as an end piece. Accordingly, in the present case, the terms "stator outer part" and "end piece" can be interchanged with one another as desired. The stator outer part 228 is connected to the pump housing 217 in a rotationally fixed manner. The stator 227 is detachably connected to the pump housing 217 by means of the stator outer part 228. The stator outer part 228 can be screwed, clamped or connected detachably in some other way to the pump housing 217. The stator outer part 228 can be manufactured from a metallic material, for example from stainless steel.The stator inner part 229 is mounted in the stator outer part 228 in a rotationally fixed manner. The stator inner part 229 can project at least in sections into the pump housing 217. The stator inner part 229 is manufactured in particular from an elastomer, such as rubber. The stator inner part 229 has a helical or helical inner geometry corresponding to the outer geometry of the rotor 214. For this purpose, a worm-shaped or helical aperture is provided centrally in or on the stator inner part 229. The stator outer 228 and the stator inner 229 are interchangeable.When the rotor 214 rotates in the stator 227, in particular in the stator inner part 229, about the central axis 205, the electrolyte E is conveyed by the interaction of the rotor 214 with the stator inner part 229 in the longitudinal direction L away from the drive shaft 212 from an inlet side 230 in the direction of an outlet side 231 of the stator 227, in particular of the stator inner part 229, according to the endless piston principle. A delivery volume of the eccentric screw pump 200 per unit time is dependent on a rotational speed, a size, a pitch and a geometry of the rotor 214.By reversing a direction of rotation of the rotor 214, it is possible to reverse a conveying direction of the eccentric screw pump 200 or of the eccentric screw pump device 204 from the inlet side 230 to the outlet side 231, so that conveying is effected from the outlet side 231 in the direction of the inlet side 230. As a result, it is possible, for example, to feed back or suck back the electrolyte E. This can be used, for example, to prevent droplet formation.The at least partially elastically deformable stator 227, in particular the stator inner part 229, preferably has a thread turn more than the rotor 214 and twice the pitch length of the rotor 214. As a result, between the stator 227, in particular the stator inner part 229, and the rotor 214 rotating therein and additionally moving radially, in particular mutually separate, conveying spaces are formed, which move continuously from the inlet side 230 to the outlet side 231.Valves for delimiting the delivery spaces are not required. A size of the delivery spaces and thus the theoretical delivery rate depends on the pump size. A 360 degree rotation of the rotor unit 211 with free runout yields the volumetric flow rate per revolution. A delivery quantity, in particular a delivery speed, of the eccentric screw pump 200 can thus be varied via the rotational speed of the rotor unit 211. The actual delivery rate is dependent on a back pressure of the electrolyte E which is established.The shape of the delivery spaces is constant, so that the electrolyte E is not compressed. The shear forces acting on the electrolyte E are very low. A particular advantage of such an eccentric screw pump 200 is that the eccentric screw pump 200 delivers continuously and with little pulsation. In particular, as mentioned above, the conveying direction of the eccentric screw pump 200 can be reversed by reversing the direction of rotation of the rotor unit 211, in particular of the rotor 214.FIG. 4 shows a schematic perspective view of an embodiment of a filling adapter 300 as mentioned above. FIG. 5 shows a schematic sectional view of the filling adapter 300. Reference is made simultaneously to FIGS. 4 and 5 below.The filling adapter 300 comprises a central distributor block 301. The distributor block 301 can be, for example, rectangular parallelepipedal. The manifold block 301 may be made of a metallic material. A fluid channel 302 runs through the distributor block 301, through which the electrolyte E flows during operation of the filling adapter 300. A valve bore 303 runs through the distributor block 301 perpendicularly to the fluid channel 302. The fluid channel 302 opens into the valve bore 303.A metering pressure sensor 304 protrudes into the valve bore 303. The metering pressure sensor 304 is connected to the manifold block 301 by means of a screw-in sleeve 305 which is screwed into the manifold block 301. The dosing pressure sensor 304 may be opposite the fluid passage 302. This means that the electrolyte E flows against the metering pressure sensor 304 out of the fluid channel 302. By means of the metering pressure sensor 304, for example, a metering pressure of the electrolyte E generated by the eccentric screw pump 200 can be detected. A speed of the rotor 214 may be varied or regulated based on sensor signals from the dosing pressure sensor 304.Opposite the metering pressure sensor 304, an adapter piece 306 is flanged to the distributor block 301. The adapter piece 306 can be manufactured from a metallic material. The adapter piece 306 can be cuboidal. The adapter piece 306 can be screwed to the distributor block 301, for example.A fluid channel 307 runs through the adapter piece 306. The fluid channel 307 of the adapter piece 306 is in fluid communication with the fluid channel 302 which runs through the manifold block 301. The fluid channel 307 carries out a direction deflection by 90° within the adapter piece 306. This means in particular that the fluid channel 307 runs at least in sections parallel to the fluid channel 302 and at least in sections perpendicular to the fluid channel 302.A connecting flange 308 is integrally formed on the adapter piece 306, on which the stator 227, in particular the stator outer part 228, of the eccentric screw pump 200 bears. The connecting flange 308 can receive the stator 227 at least in sections. The fluid channel 307 widens within the connecting flange 308 to an inlet bore 309. The inlet bore 309 is in fluid communication with the exit side 231 of the stator 227. The inlet bore 309 may have the same inner diameter as the exit side 231 of the stator 227.A union nut or a threaded sleeve 310 is attached to the connection flange 308, which nut or sleeve can be screwed onto the stator 227, in particular onto the stator outer part 228, in order to connect the filling adapter 300 to the eccentric screw pump 200 in a releasable manner. The threaded sleeve 310 is connected to the connecting flange 308 with the aid of a securing ring 311.The filling adapter 300 further includes a filling valve 312 that can be opened and closed. The filling valve 312 is firmly connected to the distributor block 301, for example screwed to the latter. The distributor block 301 can be at least partially part of the filling valve 312. However, this is not absolutely necessary. The fill valve 312 may also be partially disposed within the manifold block 301.The filling valve 312 has a symmetry or center axis 313, with respect to which the filling valve 312 is constructed substantially rotationally symmetrically. The central axis 205 of the eccentric screw pumping device 204 and the central axis 313 run parallel to one another and are positioned offset from one another.The fill valve 312 includes a fill valve housing 314. The filling valve housing 314 is made of a metallic material. The filling valve housing 314 is firmly connected to the distributor block 301, for example screwed to the latter, and is sealed with respect to the latter with the aid of a sealing element 315, for example in the form of an O-ring. The filling valve housing 314 includes a plate-shaped flange portion 316 that is connected to the manifold block 301 and that receives the sealing member 315.A tubular valve portion 317 extends out of the flange portion 316. The valve portion 317 may be configured rotationally symmetrically to the central axis 313. The fill valve housing 314, in particular the valve portion 317, includes a valve bore 318 in fluid communication with the valve bore 303 of the manifold block 301. The two valve bores 303, 318 can be constructed rotationally symmetrically to the central axis 313.The valve bore 318 of the filling valve housing 314 narrows to a tubular or hollow cylindrical nozzle needle 319, which on the inside has a smaller diameter than the valve bore 318. At the end of the valve bore 318, a frustoconical or conical valve seat 320 is placed, from which the nozzle needle 319 opens out centrally. At the end face, the valve section 317 has an annular end face 321. The nozzle needle 319 protrudes beyond the end face 321. The end face 321 comprises a groove in which a sealing element 322, in particular in the form of an O-ring, is accommodated.The filling adapter 300 further comprises a docking unit 323 which is linearly displaceable relative to the filling valve housing 314 along the central axis 313. The docking unit 323 may be part of the fill valve 312. However, this is not absolutely necessary. The docking unit 323 is mounted in a linearly movable manner on the filling valve 312, in particular on the filling valve housing 314. The valve section 317 is accommodated at least in sections in the docking unit 323. The docking unit 323 comprises a threaded sleeve 324 which is protected against being removed from the filling valve housing 314 with the aid of a securing ring 325 which engages in an annular groove provided on the outside of the valve section 317. The valve portion 317 is passed through the threaded sleeve 324.A spring element 326 is arranged between the threaded sleeve 324 and the flange section 316. The spring element 326 is in particular a compression spring. The spring member 326 biases the docking unit 323 to be pushed away from the flange portion 316. The spring element 326 can be compressed by moving the docking unit 323 along the central axis 313 towards the flange section 316 or towards the distributor block 301. In this case, the threaded sleeve 324 is lifted off the securing ring 325. For this purpose, a force is applied to the docking unit 323. If this force no longer acts on the docking unit 323, then this moves away from the flange section 316 due to the prestress of the spring element 326, until the threaded sleeve 324 again abuts against the securing ring 325.A nozzle insert 327 is screwed into the threaded sleeve 324. The nozzle insert 327 is part of the docking unit 323. The valve portion 317 is at least partially passed through the nozzle insert 327. The nozzle insert 327 is made of a metallic material. The nozzle insert 327 is tubular. In particular, the nozzle insert 327 has a central bore 328 in which the valve portion 317 is received.The docking unit 323 is mounted linearly displaceably on the valve section 317 with the aid of the nozzle insert 327 and sealed off with respect to the latter in a fluid-tight manner. For this purpose, a guide ring 329 is provided, which is accommodated in an annular groove provided on the outside of the valve section 317. With the aid of the guide ring 329, the nozzle insert 327 is mounted on the valve section 317 in a linearly displaceable manner. With the aid of a sealing element 330, in particular in the form of an O-ring, which is accommodated in an outer annular groove of the valve section 317, the nozzle insert 327 is sealed in a fluid-tight manner with respect to the valve section 317.The nozzle insert 327 has an end face 331 oriented downward in the orientation of FIG. 5. The end face 331 extends annularly around the central axis 313. On the end face 331, a sealing element 332, in particular in the form of an O-ring, is accommodated in a corresponding groove.A vacuum port or evacuation port 333 is attached to the nozzle insert 327. The evacuation port 333 may be connected to a vacuum pump or vacuum pump. The evacuation port 333 opens into the bore 328 to apply a negative pressure or vacuum to the bore 328.The fill valve 312 further includes a needle-shaped valve body 334. The valve body 334 may therefore also be referred to as a valve needle. The valve body 334 is arranged within the valve portion 317 and within the distributor block 301, in particular within the valve bores 303, 318. The structure of the valve body 334 will be explained later with reference to FIGS. 6 and 7.The valve body 334 can be displaced upward and downward along the central axis 313 in the orientation of FIG. 5 by means of an actuator or adjusting element 335. The actuator 335 may be a pneumatic cylinder. Alternatively, the adjusting element 335 can also be an electric motor, in particular a linear electric motor, or can have an electric motor. The actuator 335 may also include an electromagnet configured to move the valve body 334 to open and close the charge valve 312.It is assumed below that the adjusting element 335 is a pneumatic cylinder as mentioned above. The adjusting element 335 is fixedly connected, for example screwed, to the distributor block 301. The actuator 335 may include a housing 336 in which a movable piston 337 is disposed. The piston 337 is connected, for example screwed, to the valve body 334. The piston 337 is double acting. Alternatively, the piston 337 may also be single acting. In the latter case, the piston 337 is then spring-biased. The actuating element 335 comprises two pneumatic connections 338, 339, with the aid of which the actuating element 335 can be connected to a pneumatic system, in particular comprising a compressor or a compressed air bottle.Alternatively, the adjusting element 335 can also be integrated into the distributor block 301, for example (not shown). In this case, too, the adjusting element 335 is a pneumatic cylinder. The advantage is then a particularly compact design and an optimized connection and integration of a seal of a valve body shaft of the valve body 334. The integrated construction also makes it possible to realize a multiple housing, for example five times.The valve body 334 is supported within the manifold block 301 by means of guide rings 340, only one of which is designated by a reference numeral, and is sealed from the manifold block 301 by means of sealing members 341, also only one of which is designated by a reference numeral. Two such guide rings 340 and two such sealing elements 341 may be provided. Between the distributor block 301 and the housing 336 of the adjusting element 335, a sealing block 342 can be arranged which holds the guide rings 340 and the sealing elements 341 in position. The sealing block 342 may be bolted to the manifold block 301.FIG. 6 shows a schematic view of an embodiment of a valve body 334 as mentioned above. FIG. 7 shows a schematic sectional view of the valve body 334 along the section line VII-VII of FIG. 6 ; FIGS. 6 and 7 are simultaneously referred to below.In FIG. 7, the nozzle insert 327, the evacuation connection 333 and the valve section 317 of the filling valve housing 314 with the valve bore 318 are shown. As mentioned previously, the valve body 334 is received in the valve bores 303, 318. The valve body 334 may be made of a metallic material or a ceramic material.The valve body 334 includes a rod-shaped valve body shaft 343. The valve body shaft 343 may be circular in cross section. However, the valve body shaft 343 can have basically any desired cross-sectional geometry. The valve body shaft 343 has a smaller diameter than the valve bores 303, 318, so that this does not contact inner surfaces of the valve bores 303, 318.In the orientation of FIG. 6, a bearing section 344 is arranged on the top side of the valve body shaft 343, which bearing section has a larger diameter than the valve body shaft 343. The bearing portion 344 is supported on the guide rings 340. On the top side of the bearing section 344, a fastening section 345 extends. The fastening portion 345 may have an external thread that is screwed into a corresponding internal thread of the piston 337 of the adjusting element 335.Arranged on the end side of the valve body shaft 343 and facing away from the fastening portion 345, the valve body 334 comprises a valve body head 346. The valve body head 346 comprises a plurality of abutment portions 347, of which only one is provided with a reference sign in FIG. 7. The valve body head 346 rests with its contact portions 347 on the inside on the valve bore 318. A number of the abutment portions 347 is arbitrary. Purely by way of example, four such contact sections 347 are provided in FIG. 7. With the aid of the contact sections 347, the valve body head 346 is mounted linearly displaceably on the inside in the valve bore 318.Between the contact sections 347, flow openings 348 are provided, through which the electrolyte E can flow. The contact sections 347 and the flow openings 348 are arranged alternately, so that a flow opening 348 is always arranged between two contact sections 347 and a contact section 347 is always arranged between two flow openings 348. With the aid of the flow openings 348, the valve body head 346 is designed to be fluid-permeable.In order to make the valve body head 346 fluid-permeable, the valve body head 346 can alternatively have, as an alternative to the contact portions 347, bores, apertures, channels or the like, through which the electrolyte E can flow. Furthermore, the valve body head 346 can also be manufactured at least in sections from a porous, in particular open-pore, material, such as a metal foam or a ceramic foam. The fluid permeability of the valve body head 346 can also be achieved in this way.The valve body head 346 has a frustoconical or conical end face 349 which points toward the valve seat 320 of the valve section 317 of the filling valve housing 314. At the end face, a needle section 350 extends out of the valve body head 346. The needle section 350 is accommodated in the nozzle needle 319 of the valve section 317 of the filling valve housing 314. A sealing element 351, in particular in the form of an O-ring, is arranged on the needle section 350. With the aid of the sealing element 351, the valve body 334 can be sealed in a fluid-tight manner with respect to the valve portion 317, in particular with respect to the valve seat 320.FIG. 8 shows a schematic perspective view of an embodiment of an arrangement 400 having a filling device 100 as explained above and an accumulator cell 500.FIG. 8 shows only the filling adapter 300 of the filling device 100 explained above, on which the eccentric screw pump 200 is mounted. The eccentric screw pump 200 is not shown in FIG. 8. In FIG. 8, for the sake of simplified illustration, the individual parts of the filling adapter 300 explained above are furthermore not provided with reference numerals. The arrangement 400 comprises the filling device 100 and the accumulator cell 500. The arrangement 400 can have any number of accumulator cells 500. The accumulator cell 500 is represented purely by way of example as a cylindrical accumulator cell. However, the accumulator cell 500 may also be a prismatic accumulator cell. The battery cell 500 is a lithium ion battery cell.FIG. 9 shows a schematic view of an embodiment of a holder 109 for the accumulator cell 500. FIG. 10 shows a schematic sectional view of the holder 109 along the section line X-X of FIG. 9 ; FIGS. 9 and 10 are simultaneously referred to below.The holder 109 is part of the filling device 100. The holder 109 can be manufactured from a metallic material. The holder 109 comprises a tubular receiving piece 110 with a radial window 111. The window 111 facilitates removal of the rechargeable battery cell 500 from the holder 109 and insertion of the rechargeable battery cell 500 into the holder 109. A fastening element 113, in particular in the form of a screw, and a pin 114 can be attached to a base 112 of the receiving piece 110. By means of the fastening element 113, the holder 109 can be attached to a fixed structure. The pin 114 ensures a rotation prevention.It is also possible to mount a plurality of holders 109 on a rotatably mounted disk, in particular on a rotary table. A plurality of accumulator cells 500 can then be prepared for filling with the electrolyte E. This disk can then be driven by means of a drive, for example in the form of a stepper motor, in order to fill the prepared accumulator cells 500 successively with the electrolyte E. This allows the cycle time for filling a plurality of accumulator cells 500 to be reduced.FIG. 11 shows a schematic perspective view of an embodiment of a linear spindle unit 115 for the filling device 100.The linear spindle unit 115 is part of the filling device 100. With the aid of the linear spindle unit 115, the eccentric screw pump 200 together with the filling adapter 300 can be moved toward and away from the accumulator cell 500. However, it is also conversely possible to move the accumulator cell 500 to the fixed eccentric screw pump 200. This may be advantageous for weight reasons, since a rechargeable battery cell 500 has a significantly lower weight than the eccentric screw pump 200 with the filling adapter 300.The linear spindle unit 115 comprises a base plate 116, on which two fastening clamps 117, 118 for mounting the eccentric screw pump 200 on the linear spindle unit 115 are attached on the front side. A spindle linear table 119 is mounted on the rear side of the base plate 116. With the aid of the fastening clamps 117, 118, the eccentric screw pump 200 can be detachably connected to the linear spindle unit 115. A simple exchange of the eccentric screw pump 200 together with the filling adapter 300, for example for cleaning purposes, is thereby easily possible.A drive 120 of the linear spindle unit 115, for example an electric motor, drives a central drive spindle 121 which is mounted in the spindle linear table 119. The spindle linear table 119 may support a threaded piece or a spindle counterpart that engages with the drive spindle 121. The drive 120 is mounted on a first mounting element 122. The drive spindle 121 is also rotatably mounted in the first mounting element 122. The drive spindle 121 is furthermore additionally rotatably mounted in a second mounting element 123. The mounting elements 122, 123 are fastened, for example, to a fixed structure.Guide rails 124, 125 run between the two mounting elements. The guide rails 124, 125 are firmly connected to the mounting elements 122, 123. The linear spindle table 119 is mounted on the guide rails 124, 125 in a linearly displaceable manner. If the drive spindle 121 is now driven by means of the drive 120, the spindle linear table 119 together with the base plate 116 and the eccentric screw pump 200 fastened thereto moves upwards or downwards in the orientation of FIG. 11, as is indicated by means of a double arrow 126.FIG. 12 shows a schematic perspective view of an embodiment of a valve and sensor arrangement 127 for the filling device 100.The valve and sensor arrangement 127 is part of the filling device 100. The valve and sensor arrangement 127 comprises a pressure sensor 128 which is connected into a vacuum line leading to the evacuation connection 333. Furthermore, the valve and sensor arrangement 127 has a valve 129, which is likewise connected into the vacuum line. The valve 129 is thus associated with the evacuation port 333. The valve 129 may be a 3 / 2-way valve.In addition, the valve and sensor arrangement 127 has a further valve 130, with the aid of which the piston 337 of the actuating element 335 can be actuated. The valve 130 is thus assigned to the filling valve 312. The filling valve 312 can thus be activated, in particular opened and closed, with the aid of the valve 130. The valve 130 may be a 5 / 2 directional control valve.The filling device 100 further comprises a vacuum pump or vacuum pump 131 for applying a vacuum or vacuum to the evacuation connection 333 and thus to the accumulator cell 500, and a compressor 132 for pressurizing the piston 337 of the adjustment 335.The filling device 100 also includes a control unit 133 and a display unit 134. The control unit 133 may be a computer or may include a computer. The display unit 134 may be part of the control unit 133. The display unit 134 may be, for example, a screen or a display. The vacuum pump 131, the compressor 132, the control unit 133 and the display unit 134 are only shown very schematically in FIG. 12. The control unit 133 can be used to actuate the filling device 100, in particular the eccentric screw pump 200, the linear spindle unit 115 and / or the filling valve 312.The filling device 100 can furthermore have a box-shaped safety cell (not shown), within which the eccentric screw pump 200, the filling adapter 300, the holder 109 with the accumulator cell 500 and the linear spindle unit 115 are arranged. Within the safety cell, controlled conditions, such as a defined gas pressure, a defined air humidity and / or a defined temperature, may prevail.In particular, the safety cell can be flushed with dried air in order to prevent contact of the electrolyte E with water vapor in the event of possible escape of the electrolyte E. Furthermore, the safety cell prevents the user of the filling device 100 from being able to come into contact with the moving eccentric screw pump 200, which is moved with the aid of the linear spindle unit 115. The risk of jamming of the body parts of the user is thereby significantly reduced.FIG. 13 shows a schematic sectional view of an accumulator cell 500 as mentioned above. FIG. 14 shows a schematic view of an embodiment of a cell body 501 for the accumulator cell 500. Reference is made simultaneously to FIGS. 13 and 14.The accumulator cell 500 is a cylindrical accumulator cell in the present case. The accumulator cell 500 can, however, also be a prismatic accumulator cell, in particular a so-called hard case cell. The accumulator cell 500 can be constructed rotationally symmetrically with respect to a symmetry or center axis 502.The accumulator cell 500 comprises a pot-shaped housing 503, in which the cell body 501 is accommodated. In particular, the housing 503 encloses an interior space 504, within which the cell body 501 is arranged. In the orientation of FIG. 13, the housing 503 is closed on the top side by a cover 505. The cover 505 has a closable filling opening 506, through which the electrolyte E can be filled into the housing 503.The accumulator cell 500 can have, for example, a diameter d of 21 mm or 46 mm and a length 1 of 70 mm, 80 mm, 90 mm or 120 mm. However, the aforementioned values for the diameter d and the length 1 can be selected as desired.As FIG. 14 shows, the cell body 501 comprises an anode 507 and a cathode 508. A separator 509 is placed between the anode 507 and the cathode 508. Furthermore, a further separator 510 is placed on the outside of the cathode 508. The anode 507, the cathode 508 and the separators 509, 510 are arranged alternately in layers. Specifically, the anode 507, the cathode 508 and the separators 509, 510 are spirally wound to form the cell body 501. In FIG. 14, the cell body 501 is shown partially unrolled. In the case where the accumulator cell 500 is a prismatic accumulator cell, the cell body 501 is folded many times and is not rolled up or wound up.The anode 507, the cathode 508 and the separators 509, 510 are surrounded by the electrolyte E, which enables a transport of lithium ions. The anode 507 is the negative pole during a discharging operation of the battery cell 500, and is made of a copper foil having a thickness of about 8 μm to 18 μm coated with an active material, for example graphite, and additives. Copper foils have a high stability in the electrochemical potential range of the anode 507 and do not react with lithium or the electrolyte E. Graphite is suitable as anode material because of its low density and the low cost. In addition, graphite has a high capacity within an electrochemical working range of 0 V to 5 V.The cathode 508 functions as a counter pole to the anode 507 and is made of an aluminum foil having a thickness of about 15 μm to 25 μm, which serves as a current collector. This aluminum foil is likewise coated with an active material and additives. Lithium nickel cobalt aluminum oxides (NCA), lithium cobalt oxide (LCO), and lithium nickel manganese cobalt oxide (NMC) are the most commonly used active materials for the cathode 508.The separators 509, 510, which are microporous membranes, isolate the anode 507 and the cathode 508 from each other and thus prevent direct contact and hence short circuit. At the same time, the separators 509, 510 must be permeable to lithium ions to allow ion transport. For the separators 509, 510, polyethene (PE) and / or polypropene (PP) can be used, for example. These materials are preferably used because of their price and chemical stability. Conductivity can be increased by using a thin separator 509, 510, while a thicker separator 509, 510 increases safety.Between the anode 507 and the cathode 508 is the electrolyte E, the primary function of which is to enable the transport of lithium ions from the anode 507 to the cathode 508 during a discharge of the accumulator cell 500 or from the cathode 508 to the anode 507 during a charging of the accumulator cell 500.During charging and discharging, lithium ions are incorporated or removed from the cathode 508 and the anode 507 by an electrochemical reaction. Lithium ions move through the electrolyte E from the anode 507 to the cathode 508 or vice versa. The anode material is oxidized and releases electrons, which pass to the cathode 508 via an external circuit.On the foils of the cathode 508 and the anode 507 there is in each case a porous layer of the respective active material with the additives used. Pores of these layers typically have sizes in the nano- or micrometer range, which vary depending on the material used and the manufacturing process. There are open and closed pores. Open pores can be wetted by the electrolyte E and thus participate in the electrochemical reaction. Closed pores, on the other hand, have a negative effect on the performance of the accumulator cell 500. The capillary effect draws the electrolyte E into open pores.For a series production of rechargeable battery cells 500 with cycle times that are as short as possible, it is thus desirable to wet the anode 507, the cathode 508 and the separators 509, 510 with the electrolyte E as quickly and as completely as possible, so that no air bubbles or air-filled pores remain within the interior space 504 of the housing 503 of the rechargeable battery cell 500.FIG. 15 shows a schematic block diagram of an embodiment of a procedure for filling the rechargeable battery cell 500 with the electrolyte E. FIGS. 16, 17, 18, 19 to 20 each show a schematic detailed sectional view of the arrangement 400. In the following, reference is made simultaneously to FIGS. 15, 16, 17, 18, 19 to 20.In other words, FIGS. 15, 16, 17, 18, 19 to 20 show a filling process for filling the accumulator cell 500. FIGS. 16, 17, 18, 19 to 20 show only a part of the filling adapter 300 in each case. In FIGS. 16, 17, 18, 19 to 20, substantially only those components which are referred to in the following description are provided with a reference sign. The eccentric screw pump 200 is not shown in FIGS. 16, 17, 18, 19 to 20.As FIG. 15 shows, the procedure for filling the accumulator cell 500 can be divided into a starting process 401, a positioning process 402, an evacuation process 403, a metering process 404 and a process process 405 which are carried out successively in time.With a step S 1, the starting process 401 is started. After step S 1, a check is made in a step S 2 as to whether the safety cell of the filling device 100 is closed and whether the filling device 100 is ready for operation. If this is not the case, an error message or the like can be output in a step S 3. The error message can be output, for example, with the aid of the display unit 134 (FIG. 12 ). If the safety cell is closed and / or the filling device 100 is ready for operation, the method can continue with the positioning process 402.The positioning process 402 begins with a step S 4, in which the eccentric screw pump 200 together with the filling adapter 300 is moved into an initial position or starting position shown in FIG. 16 or is already located therein. In a step S 5, it is checked whether or not there is an accumulator cell 500 to be filled. If no battery cell 500 is present, an error message or the like can be output in a step S 6. The error message can be output, for example, with the aid of the display unit 134. If an accumulator cell 500 is present, the positioning process 402 can be continued.The docking unit 323 is arranged at a distance from the accumulator cell 500 in the initial position and does not contact it. In the initial position, the filling opening 506 of the accumulator cell 500 is aligned coaxially with the nozzle needle 319. This means in particular that the central axes 313, 502 are arranged coaxially with respect to one another. The spring element 326 presses the threaded sleeve 324 against the securing ring 325.The filling adapter 300, in particular the docking unit 323, is in an initial state or evacuation state Z 1 in FIG. 16. The nozzle needle 319 is closed since the valve body 334 blocks the nozzle needle 319 with its needle section 350 and the sealing element 351 is pressed between the valve seat 320 and the end face 349 of the valve body head 346 of the valve body 334. In other words, the filling valve 312 is thus closed and is in a closed state Z 10.In a step S 7, the eccentric screw pump 200 together with the filling adapter 300 is moved from the starting position towards the accumulator cell 500, as shown in FIG. 16 with the aid of an arrow 406. The eccentric screw pump 200 together with the filling adapter 300 is then in an evacuation position. Alternatively, the accumulator cell 500 can also be moved towards the filling adapter 300.As FIG. 17 shows, in the evacuation position, the end face 331 of the nozzle insert 327 comes into contact with the cover 505 of the accumulator cell 500, wherein the sealing element 332 seals the nozzle insert 327 in a fluid-tight manner with respect to the cover 505. The sealing element 332 is pressed between the cover 505 and the end face 331 of the nozzle insert 332. The filling adapter 300, in particular the docking unit 323, continues to remain in the evacuation state Z 1. That is, the spring element 326 is not compressed and the threaded sleeve 324 continues to abut the snap ring 325. This can be achieved by a suitable design of the spring element 326.The sealing member 351 of the valve body 334 seals against the valve portion 317. In other words, the filling valve 312 is thus still closed and is in a closed state Z 10. The sealing element 330 seals the valve section 317 in a fluid-tight manner with respect to the nozzle insert 327. A space enclosed by the bore 328 of the nozzle insert 327 and the interior space 504 of the housing 503 of the accumulator cell 500 can now be subjected to a negative pressure in a step S 8 by switching the valve 129 via the evacuation connection 333, as is shown in FIG. 17 with the aid of an arrow 407.After the step S 8 of starting evacuating the housing 503, the evacuation process 403 is started with a step S 9 of evacuating the accumulator cell 500. During the evacuation process 403, the housing 503 is evacuated until a desired negative pressure of, for example, 50 mbar absolute is reached in the housing 503. The vacuum in the housing 503 may be sensed using the pressure sensor 128. In a step S 10, it is checked whether the desired negative pressure is reached. If the desired negative pressure is not reached, step S 9 is carried out further.Once the desired negative pressure has been reached, the eccentric screw pump 200 together with the filling adapter 300 is moved in a step S 11 into a filling position shown in FIG. 18. The vacuum is detected or monitored by means of the pressure sensor 128. The filling position differs from the evacuation position in that the eccentric screw pump 200 together with the filling adapter 300 is moved closer to the accumulator cell 500 in the filling position than in the evacuation position.In step S 11, the docking unit 323 is displaced or displaced from the evacuation state Z 1 along the central axis 313 into a filling state Z 2 shown in FIG. 18, as shown with the aid of an arrow 408. As a result, the spring element 326 is compressed and the threaded sleeve 324 is lifted from the securing ring 325. In particular, the filling adapter 300 is hereby moved from the evacuation state Z 1 into the filling state Z 2.The end face 321 of the valve section 317 comes into contact with the cover 505 of the accumulator cell 500, wherein the sealing element 322 is compressed in order to seal the valve section 317 at the end face in a fluid-tight manner with respect to the cover 505. Furthermore, the nozzle needle 319 is inserted into the filling opening 506 of the accumulator cell 500. The filling valve 312 is also closed.With the aid of the sealing element 322, the space enclosed by the bore 328 is now separated from the interior space 504 of the housing 503 in a fluid-tight manner. The vacuum is maintained in the housing 503. The valve 129 can be opened to disconnect the vacuum pump 131 from the evacuation port 333. This is done in a step S 12. Filling valve 312 is still closed, since sealing element 351 is pressed between end face 349 of valve body 334 and valve seat 320 of valve section 317. In other words, the charge valve 312 is in the closed state Z 10. In the filling state Z 2, the tubular nozzle needle 319 is located in the filling opening 506 of the cover 505 of the accumulator cell 500.As FIG. 19 shows, the filling valve 312 is now opened in a step S 13 by lifting the valve body head 346 of the valve body 334 together with the sealing element 351 from the valve seat 320 along the central axis 313 with the aid of the actuating element 335, which is preferably a pneumatic cylinder. To this end, the valve 130 is operated to move the piston 337 of the actuator 335. The filling valve 312 is thereby moved from the closed state Z 10 into an open state Z 20 shown in FIG. 19. The closed state Z 10 may also be referred to as a closed position. The open state Z 20 may also be referred to as an open position.Preferably, the fill valve 312 is a pure on-off valve. In other words, the fill valve 312 may optionally be either fully closed, namely in the closed state Z 10, or fully open, namely in the open state Z 20. Intermediate positions or intermediate states between the closed state Z 10 and the open state Z 20 are preferably not provided and cannot be started up with the aid of the actuating element 335. The filling valve 312 does not serve for the metering of the electrolyte E. The metering of the electrolyte E takes place exclusively with the aid of the eccentric screw pump 200. This enables a simple construction of the filling valve 312 and of the actuating element 335.The needle section 350 of the valve body 334 is moved out of or pulled out of the tubular nozzle needle 319 of the filling valve 312 when the filling valve 312 is opened. In other words, in the closed state Z 10, the needle portion 350 is located inside the nozzle needle 319, and in the open state Z 20, the needle portion 350 is located outside the nozzle needle 319. At this time, the valve bore 318 is already filled with the electrolyte E, so that during the following dosing process 404 no air reaches the accumulator cell 500.The metering process 404 of the electrolyte E can now be started with the aid of the eccentric screw pump 200 in a step S 14, as is indicated in FIG. 19 with the aid of an arrow 409. For this purpose, the rotor 214 of the eccentric screw pump 200 is set in rotation. A metering-pressure-regulated metering takes place into the negative pressure prevailing in the accumulator cell 500. For the pressure-regulated dosing, the dosing pressure of the electrolyte E is detected with the aid of the dosing pressure sensor 304. Based on this metering pressure, the drive unit 202 can be activated to change a rotational speed of the rotor 214.In a step S 15, it is checked whether or not a desired metering volume is reached. In other words, it is checked whether or not the battery cell 500 is sufficiently filled with the electrolyte E. The dosing volume may be determined by a number of rotations performed by the rotor 214. For this purpose, the drive unit 202 has a suitable sensor system.If the desired metering volume is not reached, a check is made in a step S 16 as to whether or not the metering pressure detected with the aid of the metering pressure sensor 304 is above a predefined value. If the metering pressure is above the predetermined value, the metering speed is reduced in a step S 14.1. If the metering pressure is not above the predetermined value, the metering speed is increased in a step S 14.2. Once the desired metering volume has been reached, the pressure-regulated metering is ended in a step S 17. The dosing process 404 is complete.The process operation 405 begins with a step S 18 of checking a residual pressure in the accumulator cell 500. For this purpose, the filling valve 312 can be closed and the filling adapter 300 can be moved back into the evacuation state Z 1. The residual pressure is then checked with the aid of the pressure sensor 128. In a step S 19, a pressure reduction takes place in the accumulator cell 500 to, for example, 0 bar.As FIG. 20 shows, the filling valve 312 is then finally closed in a step S 20 by the valve body 334 being moved downward in the orientation of FIG. 20 with the aid of the actuating element 335, as is indicated with the aid of an arrow 410. The sealing elements 322, 332 still rest against the cover 505 of the accumulator cell 500. The spring element 326 remains compressed. That is, the filling adapter 300 initially remains in the filling state Z 2.Pressure compensation or vacuum compensation takes place. The vacuum line connected to the evacuation port 333 can be opened to the atmosphere. Subsequently, in a step S 21, the filling adapter 300 returns to the initial position shown in FIG. 16. As a result, the filling adapter 300 is moved back into the evacuation state Z 1. The filling process ends with a step S 22. Subsequently, the filling opening 506 may be caulked or welded to close the battery cell 500.The dosing process 404 can also be carried out with a partial quantity dosing. Such a partial quantity metering can be advantageous in the case of larger and / or very high accumulator cells 500 or a cell body 501 stacked very tightly. This ensures 100% wetting with the electrolyte E. Air inclusions in the accumulator cell 500 are also prevented. In this case, the dosing process 404 comprises steps S 9 and S 14 arranged in a row a plurality of times. In other words, a vacuum is applied multiple times to the accumulator cell 500 and subsequently metered.Furthermore, a "pressure massage" can also be carried out during the dosing process 404. For this purpose, a vacuum is first drawn at the accumulator cell 500 up to a pressure of 50 mbar absolute, with subsequent sealing. As a result, the gases, in particular air, are removed from the accumulator cell 500. The pressure-regulated metering of the bubble-free electrolyte E into the sealed accumulator cell 500 takes place. Filling in a vacuum allows the electrolyte E to foam due to the low vapor pressure in open accumulator cells (not shown).However, foaming of the electrolyte E is prevented by the rapid increase in pressure in the closed accumulator cell 500. By filling it with pressure from above into the accumulator cell 500, impregnation takes place in the form of a funnel over a wide range. The possibility of switching to vacuum drawing makes the cell bodies 501 more quickly impregnated. The metering of an exact target amount of the electrolyte E prevents gas bubbles from remaining in the accumulator cell 500. It is also possible to meter in the electrolyte E with a volume profile in order to achieve a pressure massage as mentioned above. For example, metering can be initially carried out up to, for example, 2 bar. Subsequently, the metering pressure is increased to, for example, 1 bar and a pause is set in. The mixture is then run to 2.5 bar and the metering is ended.FIG. 21 shows a schematic diagram of an embodiment of a procedure for filling the accumulator cell 500 with the electrolyte E as explained above with reference to FIG. 15.In FIG. 21, the time t is plotted on the right axis and a metering pressure p, a metering speed s and a filling volume v detected with the aid of the metering pressure sensor 304 are plotted on the vertical axis. A profile of the metering pressure p is illustrated by a solid line. A course of the metering speed s is shown with a dashed line. A course of the fill volume v is shown with a dot-dash line.The filling process begins with the evacuation of the accumulator cell 500, which leads to an initial pressure drop in the accumulator cell 500. Subsequently, the dosing is started at a predefined maximum dosing speed s in order to quickly reach a specific dosing pressure p. This metering pressure p should be kept constant for a fixed period of time. The metering speed s must thus be lowered, so that the metering pressure p remains constant, since here it is assumed in a simplified manner that the electrolyte E is constantly absorbed.In order to clarify the flexibility of different metering pressures p during the filling process, the predefined metering pressure p in FIG. 21 is increased by way of example, which is achieved by a renewed increase in the metering speed s. At the end, the metering pressure p is to be kept at a lower level. This is achieved by setting the metering speed s to zero for a short time. During this period, the fill volume v in the accumulator cell 500 does not increase.After the predetermined metering volume has been reached, the metering stops, in particular the metering speed s is equal to zero, and the filling adapter 300 remains docked until the pressure in the accumulator cell 500 has dropped to ambient pressure. The pressure drop in the accumulator cell 500 can be achieved by means of a slow reverse rotation of the rotor 214, in other words by a reversal of the direction of rotation of the rotor 214. This is carried out until the pressure has reached 0 bar. This is important so that, when the filling adapter 300 is docked off, the electrolyte E does not spray around in an uncontrolled manner and thus the contamination of components or of the housing 503 is prevented. The filling adapter 300 can then be docked off. The filling process depicted in FIG. 21 is selected purely by way of example and is used only for illustrative purposes.FIG. 22 shows a schematic block diagram of an embodiment of a method for filling the rechargeable battery cell 500 with the electrolyte E.The method according to FIG. 22 is part of the procedure explained with reference to FIG. 15 for filling the accumulator cell 500 or vice versa. In the method, as explained above with reference to FIG. 15, in a step S 100, the accumulator cell 500 is evacuated in order to generate a negative pressure within the accumulator cell 500. In a step S200, as likewise explained above with reference to FIG. 15, the electrolyte E is metered into the accumulator cell 500 with the aid of the filling device 100, in particular with the aid of the progressive cavity pump 200. In step S 200, the electrolyte E is metered into the reduced pressure prevailing in the interior 504 of the accumulator cell 500.Steps S 100 and S 200 may be performed in a time-sequential manner. It is also possible to carry out steps S 100 and S 200 alternately several times in chronological succession. For this purpose, the filling adapter 300 is moved multiple times from the evacuation state Z 1 into the filling state Z 2 and vice versa, and the filling valve 312 is opened and closed multiple times. As a result, a partial quantity metering as mentioned above and / or a "pressure massage" as mentioned above is possible. Step S 200 is in particular always carried out under pressure regulation. For this purpose, filling adapter 300 has dosing pressure sensor 304, drive unit 202 being activated on the basis of sensor data of dosing pressure sensor 304.In order to carry out steps S 100 and S 200 alternately, filling valve 312 is first closed after step S 200. The filling adapter 300 is then moved from the filling state Z 2 to the evacuation state Z 1. The accumulator cell 500 can then be evacuated again. The filling adapter 300 is then moved back into the filling state Z 2 and the filling valve 312 is opened again. This sequence can be repeated as many times as desired.Although the present invention has been described on the basis of exemplary embodiments, it can be modified in various ways.LIST OF REFERENCE CHARACTERS100 Filling device 101 cartridge 102 capacitive sensor unit 103 adapter nipple 104 reducer 105 adapter 106 joint clamp 107 curved piece 108 joint clamp 109 holder 110 receiving piece 111 window 112 base 113 fastening element 114 pin 115 linear spindle unit 116 base plate 117 fastening clamp 118 fastening clamp 119 spindle linear table 120 drive 121 drive spindle 122 mounting element 123 mounting element 124 guide rail 125 guide rail 126 double arrow 127 valve and sensor arrangement 128 pressure sensor 129 valve 130 valve 131 vacuum pump 132 compressor 133 control unit 134 display unit 200 eccentric screw pump 201 drive device 202 drive unit 203 transmission unit 204 eccentric screw pump device 205 central axis 206 shaft coupling 207 coupling star 208 bearing shaft 209 bearing 210 bearing housing 211 rotor unit 212 drive shaft 213 connecting element 214 rotor 215 flex shaft 216 casing 217 pump housing 218 feed region 219 Supply flange 220 Flange tube 221 Upper housing part 222 Sealing element 223 Sealing element 224 Protective sleeve 225 Threaded sleeve 226 Drive housing 227 Stator 228 Stator outer part 229 Stator inner part 230 Inlet side 231 Outlet side 300 Filling adapter 301 Distributor block 302 Fluid channel 303 Valve bore 304 Metering pressure sensor 305 Screw-in sleeve 306 Adapter piece 307 Fluid channel 308 Connection flange 309 Inlet bore 310 Threaded sleeve 311 Securing ring 312 Filling valve 313 Central axis 314 Filling valve housing 315 Sealing element 316 Flange section 317 Valve section 318 Valve bore 319 Nozzle needle 320 Valve seat 321 End side 322 Sealing element 323 Docking unit 324 Threaded sleeve 325 Securing ring 326 Spring element 327 Nozzle insert 328 Bore 329 Guide ring 330 Sealing element 331 End side 332 Sealing element 333 Evacuation port 334 Valve body 335 Adjusting element 336 Housing 337 Piston 338 Pneumatic port 339 Pneumatic port 340 Guide ring 341 Sealing element 342 Sealing block 343 Valve body shaft 344 Bearing section 345 Fastening section 346 Valve body head 347 Contact section 348 Throughflow opening 349 End face 350 Needle section 351 Sealing element 400 Arrangement 401 Starting process 402 Positioning process 403 Evacuation process 404 Metering process 405 Process process process process 406 Arrow 407 Arrow 408 Arrow 409 Arrow 410 Arrow 500 Accumulator cell 501 Cell body 502 Central axis 503 Housing 504 Interior space 505 Lid 506 Filling opening 507 Anode 508 Cathode 509 Separator 510 Separator d Diameter E Electrolyte l Length L Longitudinal direction p Metering pressure s Metering speed S 1 Step S 2 Step S 3 Step S 4 Step S 5 Step S 6 Step S 7 Step S 8 Step S 9 Step S 10 Step S 11 Step S 12 Step S 13 Step s 14 Step S 14.1 Step S 14.2 Step S 15 Step S 16 Step S 17 Step S 18 Step S 19 Step S 20 Step S 21 Step S 22 Step S 100 Step S 200 Step t Time v Filling volume Z 1 Evacuation state Z 2 Filling state Z 10 Closed state Z 20 Open state

Claims

Filling device (100) for filling an accumulator cell (500) with an electrolyte (E), having an eccentric screw pump (200) for metering the electrolyte (E), and a filling adapter (300) connected to the eccentric screw pump (200), which can be docked to the accumulator cell (500) for filling the accumulator cell (500) with the electrolyte (E) meterable by the eccentric screw pump (200), wherein the filling adapter (300) has a switchable filling valve (312), an evacuation connection (333) and a docking unit (323) for docking the filling adapter (300) to the accumulator cell (500), wherein the filling adapter (300) can be brought from an evacuation state (Z 1) for evacuating the accumulator cell (500) by means of the evacuation connection (333) to a filling state (Z 2) for filling the accumulator cell (500) with the electrolyte (E) and vice versa with the aid of a linear displacement of the docking unit (323) relative to the filling valve (312), wherein the evacuation connection (333) is in fluid communication with an interior space (504) of the accumulator cell (500) in the evacuation state (Z 1), and wherein the evacuation connection (333) is fluidically separated from the interior space (504) in the filling state (Z 2).Filling device (100) according to claim 1, wherein the docking unit (323) is spring-biased by means of a spring element (326) in the direction of the evacuation state (Z1).Filling device (100) according to claim 1 or 2, wherein the filling valve (312) is arranged at least in sections within the docking unit (323).Filling device (100) according to one of Claims 1-3, wherein the filling valve (312) has a filling valve housing (314) and a valve body (334) arranged within the filling valve housing (314).Filling device (100) according to claim 4, wherein the filling valve (312) comprises an adjusting element (335) which is configured to linearly displace the valve body (334) within the filling valve housing (314) in order to move the filling valve (312) in the filling state (Z2) from a closed state (Z10) into an open state (Z20) and vice versa.Filling device (100) according to claim 4 or 5, wherein the valve body (334) has a fluid-permeable valve body head (346), and wherein the valve body (334) is mounted in the filling valve housing (314) in a linearly displaceable manner with the aid of the valve body head (346).Filling device (100) according to claim 6, wherein the valve body head (346) has abutment portions (347) with the aid of which the valve body head (346) is mounted in the filling valve housing (314) in a linearly displaceable manner, and throughflow openings (348) through which the electrolyte (E) can flow.Filling device (100) according to one of Claims 4 - 7, wherein the filling valve housing (314) has a tubular nozzle needle (319), which projects beyond an end face (321) of the filling valve housing (314).Filling device (100) according to Claim 8, wherein the valve body (334) has a needle section (350) which can be arranged within the nozzle needle (319), and wherein a sealing element (351) for the fluid-tight sealing of the valve body (334) with respect to a valve seat (320) of the filling valve housing (314) has on the needle section (350).Filling device (100) according to one of claims 4 - 9, wherein the filling adapter (300) has a metering pressure sensor (304) for detecting a metering pressure (p) of the electrolyte (E), wherein the metering pressure sensor (304) projects into a valve bore (303, 318) of the filling valve (312), and wherein the valve body (334) is arranged within the valve bore (303, 318).Arrangement (400) having an accumulator cell (500) and a filling device (100) according to one of Claims 1 - 10, wherein the docking unit (323) bears against a cover (505) of the accumulator cell (500) both in the evacuation state (Z1) and in the filling state (Z2).Method for filling an accumulator cell (500) with an electrolyte (E) with the aid of a filling device (100) according to one of Claims 1 - 10, having the following steps: a) evacuating (S100) the accumulator cell (500) in order to generate a reduced pressure within the accumulator cell (500), and b) metering (S200) the electrolyte (E) into the accumulator cell (500) with the aid of an eccentric screw pump (200), wherein the electrolyte (E) is metered into the reduced pressure, and wherein the filling adapter (300) is moved from the evacuation state (Z1) into the filling state (Z2) in that the docking unit (323) is pressed against a cover (505) of the accumulator cell (500) or vice versa, whereby the docking unit (323) is linearly displaced relative to the filling valve (312).The method of claim 12, wherein steps a) and b) are performed alternately.The method of claim 12 or 13, wherein step b) is performed under pressure regulation.

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