A method of manufacturing a battery cell for a vehicle

Abstract

A method (100, fig. 1) of manufacturing a vehicle battery cell 1202 comprising applying an electrolyte to an electrode stack (302, fig. 5) to form a wetted electrode stack 1206, and subsequently assembling the wetted electrode stack in a battery cell case 1204 to form the battery cell 1202. The method may comprise providing an intermediate container (702, fig. 7) to which the electrode stack is added and then wetted with electrolyte using vacuum and compression. The electrodes may comprise one or more tabs, which can be ultrasonically welded to the battery cell case during assembly. During wetting, these tabs may be covered via sealing the one or more tabs to the intermediate container. The intermediate container, and an apparatus comprising the intermediate container and a battery cell assembly apparatus are also described.

Description

TECHNICAL FIELD The present disclosure relates to a method of manufacturing a battery cell for a vehicle. Aspects of the invention relate to a method of manufacturing a battery cell for a vehicle, to an intermediate container for forming a wetted electrode stack, to a manufacturing apparatus, and to a wetted electrode stack. BACKGROUND Batteries for battery electric vehicles typically comprise one or more battery cells each comprising an electrode stack in a battery cell case, wherein the electrode stack is wetted with an electrolyte. Known methods of manufacturing such battery cells include assembling the electrode stack in the battery cell case, adding electrolyte to the battery cell case, and waiting for a period of time to allow the electrode stack to imbibe the electrolyte and become wetted (and therefore functional). Incomplete wetting of the electrode stack may result in sub-optimal functioning of the battery cell. However, the waiting time may introduce a bottle neck in the manufacturing process, may impact the number of battery cells that can be produced, and may incur costs associated with the storage of the battery cells during this period. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a method of manufacturing a battery cell for a vehicle, to an intermediate container for forming a wetted electrode stack, to a manufacturing apparatus, and to a wetted electrode stack as claimed in the appended claims. According to an aspect of the present invention there is provided a method of manufacturing a battery cell for a vehicle, the method comprising: applying an electrolyte to electrodes to form wetted electrodes; and subsequently assembling the wetted electrodes in a battery cell case to form the battery cell. According to another aspect of the present invention there is provided a method of manufacturing a battery cell for a vehicle, the method comprising: applying an electrolyte to an electrode stack to form a wetted electrode stack; and subsequently assembling the wetted electrode stack in a battery cell case to form the battery cell. The waiting time associated with wetting of the electrode stack is therefore moved upstream (i.e. prior to assembly of the electrode stack in the battery cell case) relative to prior art methods. This may avoid the bottle neck and / or storage requirement associated with prior art methods. In certain embodiments, other manufacturing steps (e.g. formation of the battery cell case) may take place in parallel to the wetting of the electrode stack. Therefore, embodiments of the present invention may provide greater efficiencies and / or cost savings in the manufacture of vehicle battery cells in contrast to prior art methods. In certain embodiments, applying the electrolyte to the electrode stack to form the wetted electrode stack may comprise: providing an intermediate container; disposing the electrode stack in the intermediate container; and adding the electrolyte to the intermediate container to apply the electrolyte to the electrode stack to form the wetted electrode stack; the method comprising removing the wetted electrode stack from the intermediate container prior to assembling the wetted electrode stack in the battery cell case to form the battery cell. Such embodiments provide a particularly efficient and convenient means of wetting the electrode stack prior to assembly of the electrode stack in the battery cell case to form the battery cell. In certain embodiments, the method may comprise creating at least a partial vacuum in the intermediate container prior to or during adding the electrolyte to the intermediate container. The creation of the at least partial vacuum may facilitate efficient wetting of the electrode stack and therefore reduce the time required for the same. In certain embodiments, the method may comprise applying compression to the electrode stack prior to or during applying the electrolyte to the electrode stack to form the wetted electrode stack. Such compression may mitigate any risk of the electrodes unlinking from one another due to the flow. Additionally or alternatively, the application of pressure may enhance the wetting of the electrode stack by squeezing electrolyte into voids between electrodes and / or any other volumes electrolyte may enter to cause wetting of the electrode stack. In certain embodiments, the method may comprise applying compression to the wetted electrode stack to remove excess electrolyte prior to assembling the wetted electrode stack in the battery cell case to form the battery cell. Removal of excess electrolyte at this stage may facilitate greater control of a required volume electrolyte in the final assembled battery cell. In certain embodiments, the method may comprise covering one or more tabs of the electrode stack prior to applying the electrolyte to the electrode stack to form the wetted electrode stack. In doing so, the one or more tabs are shielded from the electrolyte and this may be beneficial for subsequent manufacturing steps involving the tabs (e.g. welding of the one or more tabs to the battery cell case). In certain embodiments, covering the one or more tabs may comprise sealing the one or more tabs to a part of the intermediate container. In such embodiments, the intermediate container itself may conveniently be used as the means for covering the one or more tabs. In certain embodiments, assembling the wetted electrode stack in the battery cell case to form the battery cell may comprise welding the one or more tabs to the battery cell case. Welding provides an effective method for fixing the wetted electrode stack in the battery cell case. In certain embodiments, welding the one or more tabs to the battery cell case may comprise ultrasonically welding the one or more tabs. Ultrasonic welding advantageously has a lower associated risk of creating sparks compared with other fixing methods. According to another aspect of the present invention there is provided a method of manufacturing a battery fora vehicle, the method comprising assembling one or more battery cells made in accordance with the method described above to form the battery. According to another aspect of the present invention, there is provided an intermediate container for forming a wetted electrode stack, comprising: a body; a lid connectable to the body so as to define a cavity for receiving an electrode stack; one or more electrolyte ports for introducing electrolyte into the cavity to apply the electrolyte to an electrode stack in the cavity to form a wetted electrode stack; the intermediate container being configured such that one or more tabs of the electrode stack may be received between the lid and the body when the lid is connected to the body, and when received, the one or more tabs are shielded from electrolyte introduced into the cavity. The intermediate container provides a particularly efficient and convenient means for wetting the electrode stack prior to assembly of the electrode stack in the battery cell case to form the battery cell. In certain embodiments, the intermediate container may comprise one or more vacuum ports for creating at least a partial vacuum in the cavity. The creation of the at least partial vacuum via the vacuum ports may facilitate efficient wetting of the electrode stack and therefore reduce the time required for the same. In certain embodiments, the intermediate container may comprise a compression element that is arranged to provide a compression to an electrode stack received in the cavity. Such compression may mitigate any risk of the electrodes unlinking from one another due to the flow. Additionally or alternatively, the application of pressure may enhance the wetting of the electrode stack by squeezing electrolyte into voids between electrodes and / or any other volumes electrolyte may enter to cause wetting of the electrode stack. In certain embodiments, the intermediate container may comprise an electrode stack in the cavity. According to another aspect of the present invention, there is provided a manufacturing apparatus comprising: an intermediate container as described above; and a battery cell assembly apparatus arranged to assemble a wetted electrode stack received from the intermediate container in a battery cell case to form a battery cell. The manufacturing apparatus may facilitate a more efficient manufacturing method compared with prior art methods. In certain embodiments, the manufacturing apparatus may comprise a battery assembly apparatus arranged to assemble one or more battery cells together to form a battery. According to another aspect of the present invention, there is provided a wetted electrode stack comprising an electrode stack wetted with an electrolyte, the wetted electrode stack being assemblable in a battery cell case to form a battery cell of a vehicle. The wetted electrode stack may facilitate a more efficient manufacturing method by virtue of being wetted prior to assembly in the battery cell case. According to another aspect of the present invention, there is provided a vehicle comprising the battery cell as described above. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIG. 1 shows a method of manufacturing a battery cell for a vehicle in accordance with an embodiment of the present invention; FIG. 2 shows a method of manufacturing a battery cell for a vehicle in accordance with another embodiment; FIG. 3 shows a side view of an electrode stack in accordance with an embodiment of the present invention; FIG. 4 shows a top-down view of the electrode stack of FIG. 3; FIG. 5 shows a detailed view of a part of the electrode stack of FIG. 3; FIG. 6 shows a detailed view of a part of the electrode stack of FIG. 3; FIG. 7 shows a perspective view of an intermediate container in accordance with an embodiment of the present invention; FIG. 8 shows a top-down view of the intermediate container of FIG. 7; FIG. 9 shows a cross-sectional view of the intermediate container of FIG. 8 taken along line A-A; FIG. 10 shows detail B of the intermediate container of FIG. 9; FIG. 11 shows a cross-sectional view of an intermediate container according to an embodiment of the present invention; FIG. 12 shows a schematic view of a battery cell in accordance with an embodiment of the present invention; and FIG. 13 shows a manufacturing apparatus in accordance with an embodiment of the present invention. DETAILED DESCRIPTION FIG. 1 shows a method 100 of manufacturing a battery cell for a vehicle in accordance with an embodiment of the present invention. In block 102 the method comprises applying an electrolyte to an electrode stack to form a wetted electrode stack, and in block 104 the method comprises subsequently assembling the wetted electrode stack in a battery cell case to form the battery cell. FIG. 2 shows the method 100 according to a non-limiting embodiment in which applying the electrolyte to the electrode stack to form the wetted electrode stack (block 102) comprises providing an intermediate container (block 202), disposing the electrode stack in the intermediate container (block 204), and adding the electrolyte to the intermediate container to apply the electrolyte to the electrode stack to form the wetted electrode stack (block 206). In the non-limiting embodiment of FIG. 2, the method 100 comprises removing the wetted electrode stack from the intermediate container (block 208) prior to assembling the wetted electrode stack in the battery cell case (block 104). FIG. 3 shows a side view of an electrode stack 302 in accordance with embodiments of the present invention and that may be used in methods according to embodiments of the invention. FIG. 4 shows a top-down view of the electrode stack 302 of FIG. 3. FIG. 5 shows a detailed cross-sectional view of a part of the electrode stack 302 of FIG. 3 and FIG. 4. As shown in FIG. 5, the electrode stack 302 comprises a plurality of electrodes 306 arranged in a spaced stack, where ends of the plurality of electrodes 306 merge together to form tabs 304. In certain embodiments, the tabs 304 may be formed by welding or otherwise joining the ends of the electrodes 306 together. The electrode stack 302 may be any suitable arrangement of layered electrodes 306 including linearly arranged electrodes (e.g. as described below) and rolled electrodes. The tabs 304 form electrical terminals of the electrode stack 302 (i.e. one tab 304 forms a positive terminal of the electrode stack 302 whilst the other tab 304 forms a negative terminal of the electrode stack 302). FIG. 6 shows another detailed cross-sectional view of a part of the electrode stack 302 of FIG. 3 and FIG. 4 in which it is shown that the plurality of electrodes 306 comprises a plurality of cathodes 308 and a plurality of anodes 310. The cathodes 308 and anodes 310 are alternately arranged with a separator 312 between each pair of adjacent electrodes 306. The separator 312 is porous and capable of absorbing an electrolyte so that ions may be transferred between each cathode 308 and adjacent anode 310. In the non-limiting embodiment shown in FIG. 6 at least one of the separators 312 includes at least one bend so that a single separator 312 may separate multiple pairs of adjacent electrodes 306. In certain embodiments, a single separator 312 may include multiple bends and separate all pairs of adjacent electrodes 306. As shown in FIG. 6, the separators 312 extend beyond the electrodes 306 thereby defining voids 314 between adjacent separators 312 (or adjacent parts of a single separator 312). In the non-limiting embodiment shown in FIG. 6, the separator 312 (or one of multiple separators 312) envelopes the entire electrode stack 302 and protruding (parts of) separators 312. In the non-limiting embodiment depicted in FIGs. 5 and 6, each electrode 306 comprises a current collector 316 that is coated on opposing sides with an active material 318 along a portion of the current collector 316. For example, each of the plurality of cathodes 308 may comprise an aluminium current collector coated with active material. Additionally or alternatively, each of the plurality of anodes 310 may comprise a copper current collector coated with active material. In certain embodiments, the tabs 304 may comprise the merged current collectors without the active material(s). That is, all of the current collectors 316 of the plurality of anodes 310 are merged with one another to form one tab 304 of the electrode stack 302 so that all of the plurality of anodes 310 are electrically connected to one another. Similarly, all of the current collectors 316 of the plurality of cathodes 308 are merged with one another to form another tab 304 of the electrode stack 302 so that all of the plurality of cathodes 308 are electrically connected to one another. Neither tab 304 is shown in FIG. 6, although in certain embodiments, the electrode stack 302 may be arranged as shown in the image of FIG. 6 wherein all of the current collectors 316 of one of the plurality of anodes 310 or cathodes 308 extend into the page to merge with one another to form one tab 304 whilst the current collectors 316 of the other of the plurality of anodes 310 and cathodes 308 extend in the opposite direction (out of the page) to merge with one another to form the other tab 304. In certain non-limiting embodiments, the active material on the plurality of cathodes 308 may comprise NMC811 and / or the active material on the plurality of anodes 310 may comprise graphite. The skilled person will appreciate that other suitable active materials may be utilised on either of the plurality of cathodes 308 and the plurality of anodes 310. Returning to FIG. 5, it can be seen that the electrodes 306 transition through three regions before terminating at the respective tabs 304. In a first region 320, the electrodes 306 each comprise the current collectors 316 and active material 318 and are separated from one another by the separators 312. The current collectors 316 extend from the first region 320 through a second region 322 wherein the separators 312 are disposed between adjacent current collectors 316 but in which the current collectors 316 are not coated with the active material 318. The current collectors 316 extend from the second region to a third region 324 in which the separators 312 are no longer disposed between adjacent current collectors 316. each current collector 316 then bends to join to an adjacent current collector 316 to form the tab 304. The tab 304 therefore increases in thickness as the current collectors 316 progressively join one another. FIGS. 7 to 9 show a perspective view, plan view and cross section of an intermediate container 702 in accordance with embodiments of the present invention and that may be used in methods according to embodiments of the invention. The intermediate container 702 comprises a body 704 and a lid 710 that is arranged to couple with the body 704 to define a cavity 716 of the intermediate container 702 in which the electrode stack 302 may be received. In certain embodiments, any number of electrode stacks 302 may be received in the cavity 716. In certain embodiments, the body 704 and / or lid 710 comprises a rigid component. The lid 710 comprises a lid flange 708 and the body 704 comprises a body flange 706. The lid flange 708 and body flange 706 are arranged such that they engage opposite sides of the tabs 304 when the electrode stack 302 is received in the cavity 716(described further below with reference to FIG. 9 and FIG. 10). The intermediate container 702 of FIG. 7 comprises a plurality of vacuum ports 712 arranged to create a vacuum (or at least lowerthe pressure - i.e. a partial vacuum) within the cavity 716 of the intermediate container 702. The intermediate container 702 of FIG. 7 comprises a plurality of electrolyte ports 714 arranged to permit the inflow and / or outflow of electrolyte in / out of the cavity 716. In certain embodiments, any or all of the vacuum ports 712 or electrolyte ports 714 may be provided on any suitable part of the intermediate container 702 (e.g. on any suitable part of the lid 710 or body 704). FIG. 8 shows a top-down view of the intermediate container 702 of FIG. 7. FIG. 9 shows a cross-sectional view of the intermediate container 702 of FIG. 8 taken along line A-A. FIG. 10 shows a detailed view of the part of the intermediate container 702 of FIG. 9 labelled B. As shown in FIG. 9 and FIG. 10 with the electrode stack 302 received in the intermediate container 702, the opposite sides of each tab 304 is engaged by the lid flange 708 and the body flange 706 respectively. Such engagement may create a fluid tight seal against the tabs 304. In certain embodiments, one or more elastomeric components may be provided to establish or enhance sealing between the tabs 304 and the intermediate container 702. In the non-limiting embodiment shown in FIG. 10, a pair of elastomeric components 720are disposed between the tab 304 and each of the lid flange 708 and the body flange 706. In use, the electrode stack 302 is placed in the body 704 and the lid 710 is assembled on the body 704 so that the tabs 304 are engaged by the lid flange 708 and the body flange 706. A vacuum may then be created in the cavity 716 (i.e. the pressure in the cavity 716 may be reduced) by evacuation through the vacuum ports 712. The vacuum ports 712 may then be closed. Electrolyte is then introduced into the cavity 716 through the electrolyte ports 714. The electrolyte ports 714 may then be closed. The electrode stack 302 is disposed in the intermediate container in a manner that does not impede or prevent operation of the vacuum ports 712 and electrolyte ports 714. Over a period of time following introduction of electrolyte into the cavity 716, the electrodes 306 of the electrode stack 302 imbibe the electrolyte. In particular, in the absence of any external force causing flow or other movement of the electrolyte relative to the electrode stack 302, the electrolyte may flow into the voids 314, pores of the separators 312, and any other volumes present in order to wet the electrodes 306 (e.g. by capillary action). After a predetermined period of time or when the electrodes 306 are sufficiently wetted, the electrode stack 302 may be termed a wetted electrode stack 1206 which may be removed from the intermediate container 702 and assembled in a battery cell case 1204 to form a battery cell 1202 (shown in FIG. 12). To facilitate removal of the lid 710 from the body 704, the pressure in the cavity 716 may first be increased (e.g. to atmospheric pressure). In certain embodiments, a gas (e.g. an inert gas) may be introduced into the cavity 716 (e.g. through the vacuum ports 712) to increase the pressure. In an alternative embodiment, the electrolyte ports 714 may be arranged to produce a dynamic vacuum in the cavity 716 wherein electrolyte is introduced into the cavity 716 whilst the pressure in the cavity 716 is changing (in contrast to the “static vacuum” arrangement described above). Such a dynamic vacuum may be established by providing a positive pressure through certain electrolyte ports 714 (e.g. on one side of the intermediate container 702) and providing a negative pressure through other electrolyte ports 714 (e.g. on another side of the intermediate container 702) for the outflow of electrolyte. In such embodiments, the vacuum ports 712 in the lid 710 may not be present or may not be used. Additionally or alternatively, one or more vacuum ports 712 may be repeatedly opened and closed to establish the dynamic vacuum. Once the dynamic vacuum is established, electrolyte may be continually introduced through the electrolyte ports 714. The electrolyte may consequently flow across the electrode stack 302 (possibly changing direction subject to the nature of the dynamic vacuum) causing the electrodes 306 of the electrode stack 302 to absorb electrolyte (e.g. by forced imbibition optionally in addition to naturally occurring capillary action). In particular, the electrolyte may flow into the voids 314, pores of the separators 312, and any other volumes present in order to wet the electrodes 306. In certain embodiments, compression may be applied to the electrode stack. 302 during flow of electrolyte across the electrodes 306. Such compression may mitigate any risk of the electrodes 306 unlinking from one another due to the flow. Additionally or alternatively, the application of pressure may enhance the wetting of the electrode stack 302 by squeezing electrolyte into the voids 314 and / or any other volumes electrolyte may enter to cause wetting of the electrode stack 302. In certain embodiments, the compression may be provided by additional components or features within the intermediate container 702 (e.g. one or more compression pads or biasing members in contact with the electrode stack 302. FIG. 11 shows a cross-sectional view of an intermediate container according to an embodiment of the present invention in which three electrode stacks 302 are disposed. Disposed top and bottom of the electrode stacks 302 are provided compression elements 718. The compression elements 718 support and compress the electrode stacks 302 in a direction perpendicular to the plane of the electrodes 306 of the electrode stacks 306 so as to mitigate any risk of the electrodes 306 unlinking from one another due to the flow electrolyte across the electrodes 306. In certain embodiments, the compression elements 718 may comprise a diaphragm. As the skilled person will appreciate, in alternative embodiments any number (i.e. one or more) of electrode stacks 302 may be disposed in the intermediate container 702. Similarly, in other embodiments, any number (i.e. one or more) compression elements 718 may be provided for applying compression to the electrode stack(s) 302 during flow of electrolyte across the electrodes 306. After a predetermined period of time or when the electrodes 306 are sufficiently wetted, the electrode stack 302 may be termed a wetted electrode stack 1206 which may be removed from the intermediate container 702 and assembled in a battery cell case 1204 to form a battery cell 1202 (shown in FIG. 12). Again, in order to facilitate removal of the lid 710 from the body 704, the pressure in the cavity 716 may first be increased (e.g. to atmospheric pressure). In certain embodiments, a gas (e.g. an inert gas) may be introduced into the cavity 716 (e.g. through the vacuum ports 712) to increase the pressure. During exposure of the electrode stack 302 to the electrolyte in the cavity 716, the tabs 304 remain covered or shielded so that the tabs 304 do not come into contact with the electrolyte. In the non-limiting depicted embodiment, the tabs 304 are sealed to the lid flange 708 and the body flange 706 and consequently do not come into contact with the electrolyte. In other embodiments, the tabs 304 may be otherwise covered or shielded from contact with the electrolyte. For example, the tabs 304 may seal to any suitable part of the intermediate container 702 (i.e. any part of the lid 710, and / or the body 704, and / or any other part or component of the intermediate container 702). In other embodiments, a mask may be applied to the tabs 304, wherein the mask may be removed following exposure to electrolyte. In certain embodiments, any or all parts of the above-described method may be undertaken in a gas-controlled (e.g. inert) environment to reduce any risk of contamination of the wetted electrode stack 1206. In certain embodiments, the intermediate container 702 is arranged and / or orientated during exposure of the electrode stack 302 to electrolyte such that the electrode stack 302 remains horizontally flat in the cavity 716 so that electrolyte is evenly distributed across the electrode stack 302. For example, the intermediate container 702 may be orientated horizontally flat. In alternative embodiments, the intermediate container 702 may be otherwise orientated in order to achieve optimal flow of electrolyte for wetting of the electrode stack 302, FIG. 12 schematically shows the battery cell 1202 following assembly of the wetted electrode stack 1206 in the battery cell case 1204. Assembly may comprise welding or otherwise joining the tabs 304 of the wetted electrode stack 1206 to the battery cell case 1204. The welding may comprise ultrasonic welding so as to minimise the generation of heat or other potential spark risks. Prior to welding in the battery cell case 1204, the tabs 304 may be cleaned to ensure that they are free of any electrolyte thereby reducing any potential spark or ignition risk during welding. Such cleaning may comprise blow drying, for example. In certain embodiments, excess electrolyte may be removed from the wetted electrode stack 1206 prior to welding or otherwise joining (e.g. by squeezing or otherwise providing a pressure to the wetted electrode stack 1206). In certain embodiments, additional electrolyte may be added to the battery cell case 1204 following joining of the tabs 304 to the battery cell case 1204 to ensure that the assembled battery cell 1202 contains the required volume of electrolyte. FIG. 13 schematically shows a manufacturing apparatus 1302 comprising the intermediate container 702, and a battery cell assembly apparatus 1304 arranged to assemble the wetted electrode stack 1206 received from the intermediate container 702 in the battery cell case 1204 to form the battery cell 1202. The transfer of the wetted electrode stack 1206 to the battery cell case 1204 and the subsequent assembly (e.g. welding) of the wetted electrode stack 1206 in the battery cell case 1204 may be undertaken in a gas-controlled (e.g. inert) environment. One or more of the battery cells 1202 may be assembled together to form a battery. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

1. A method of manufacturing a battery cell for a vehicle, the method comprising: applying an electrolyte to an electrode stack, to form a wetted electrode stack; and subsequently assembling the wetted electrode stack in a battery cell case to form the battery cell.

2. The method of claim 1, wherein applying the electrolyte to the electrode stack to form the wetted electrode stack comprises:providing an intermediate container;disposing the electrode stack in the intermediate container; andadding the electrolyte to the intermediate container to apply the electrolyte to the electrode stack to form the wetted electrode stack;the method comprising removing the wetted electrode stack from the intermediate container prior to assembling the wetted electrode stack in the battery cell case to form the battery cell.

3. The method of claim 2, comprising creating at least a partial vacuum in the intermediate container prior to or during adding the electrolyte to the intermediate container.

4. The method of any one of claims 1 to 3, comprising applying compression to the electrode stack prior to or during applying the electrolyte to the electrode stack to form the wetted electrode stack.

5. The method of any one of claims 1 to 4, comprising applying compression to the wetted electrode stack to remove excess electrolyte prior to assembling the wetted electrode stack in the battery cell case to form the battery cell.

6. The method of any one of claims 1 to 5, comprising covering one or more tabs of the electrode stack prior to applying the electrolyte to the electrode stack to form the wetted electrode stack.

7. The method of claim 6 when dependent on claim 2, wherein covering the one or more tabs comprises sealing the one or more tabs to a part of the intermediate container.

8. The method of claim 6 or 7, wherein assembling the wetted electrode stack in the battery cell case to form the battery cell comprises welding the one or more tabs to the battery cell case.

9. The method of claim 8, wherein welding the one or more tabs to the battery cell case comprises ultrasonically welding the one or more tabs.

10. An intermediate container for forming a wetted electrode stack, comprising:a body;a lid connectable to the body so as to define a cavity for receiving an electrode stack;one or more electrolyte ports for introducing electrolyte into the cavity to apply the electrolyte to an electrode stack in the cavity to form a wetted electrode stack;the intermediate container being configured such that one or more tabs of the electrode stack may be received between the lid and the body when the lid is connected to the body, and when received, the one or more tabs are shielded from electrolyte introduced into the cavity.

11. The intermediate container of claim 10, comprising one or more vacuum ports for creating at least a partial vacuum in the cavity.

12. The intermediate container of claim 10 or 11, comprising a compression element that is arranged toprovide a compression to an electrode stack received in the cavity.

13. The intermediate container of any one of claims 10 to 12, comprising an electrode stack in the cavity.

14. A manufacturing apparatus comprising:an intermediate container according to any one of claims 10 to 13; anda battery cell assembly apparatus arranged to assemble a wetted electrode stack received from the intermediate container in a battery cell case to form a battery cell.

15. A wetted electrode stack comprising an electrode stack wetted with an electrolyte, the wetted electrode stack being assemblable in a battery cell case to form a battery cell of a vehicle.

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