A current collector, battery cell and method of manufacturing a current collector

Abstract

A current collector (200) for connecting an electrode tab (108) of an electrode assembly (106) to an electrode terminal (104) of a case (102) in which the electrode assembly (106) is received. The current collector (200) comprises a tab part (202) configured to be welded to the electrode tab (108) and extending in a first plane; a terminal part (204) configured to be connected to the electrode terminal (104) and extending in a second plane perpendicular to the first plane; and a connection part (206) connecting the tab part (202) to the terminal part (204) to provide a first current path (Cl) between the electrode tab (108) and the electrode terminal (104), the connection part (206) extending in a third plane perpendicular to both the first plane and the second plane. The tab part (202) comprises a first weld region (212) and the terminal part (204) comprises a second weld region (214), the first and second weld regions (212, 214) welded together to provide a second current path (C2) between the electrode tab (108) and the electrode terminal (104).

Description

[0001] A CURRENT COLLECTOR

[0002] Technical Field

[0003] The present disclosure relates to a current collector for use in a battery cell and a method of manufacturing the current collector. In particular, the current collector is for connecting an electrode tab of an electrode assembly to an electrode terminal of a case in which the electrode assembly is received. The present disclosure also relates to a battery cell comprising the current collector and a method of manufacturing the battery cell.

[0004] Background

[0005] In addressing climate change, there is an increasing demand for rechargeable batteries, e.g. to enable electrification of transportation and to supplement renewable energy. Such batteries typically comprise a number of battery cells coupled together to provide the desired voltage and current.

[0006] Rechargeable or 'secondary' batteries find widespread use as electrical power supplies and energy storage systems. For example, in automobiles, battery packs formed of a plurality of battery modules, wherein each battery module includes a plurality of electrochemical cells, are provided as a means of effective storage and utilization of electric power.

[0007] Several different form factors exist for the electrochemical cells applied in secondary batteries depending on their intended application field. In automotive applications, the most common cell types are cylindrical, prismatic and pouch cells.

[0008] A battery cell stores electrical energy in an electrode assembly, which may be stacked, and referred to as an 'electrode stack', or rolled, and referred to as an 'electrode roll' or a 'jelly roll'. Stored electrical energy may then be collected and transferred to the terminals of the battery cell via current collectors, which may be adapted for (electrical) connection to the terminal(s) and to the electrode assembly. One current collector may connect between an anode of the electrode assembly and an anode terminal (negative electrode), while another current collector may connect between a cathode of the electrode assembly and a cathode terminal (positive electrode). The performance of a battery cell may be improved by enabling the conduction of electricity from electrode active material in the electrode assembly to the respective terminal as efficiently as possible. There is therefore a demand to reduce ohmic resistance throughout the components of the cell featuring along that current path.

[0009] Reducing the ohmic resistance in the current collectors of a battery cell without unduly increasing the cost, substantially complicating the manufacturing process or detrimentally effecting the structural characteristics of the component presents a challenge.

[0010] Summary

[0011] According to a first aspect of the disclosure we provide a current collector for connecting an electrode tab of an electrode assembly to an electrode terminal of a case in which the electrode assembly is received, the current collector comprising: a tab part configured to be welded to the electrode tab and extending in a first plane; a terminal part configured to be connected to the electrode terminal of the case and extending in a second plane perpendicular to the first plane; and a connection part connecting the tab part to the terminal part to provide a first current path between the electrode tab and the electrode terminal of the case, the connection part extending in a third plane perpendicular to both the first plane and the second plane, wherein the tab part comprises a first weld region and the terminal part comprises a second weld region, the first and second weld regions welded together to provide a second current path between the electrode tab and the electrode terminal of the case.

[0012] In one or more embodiments, the tab part, the terminal part and the connection part may be integrally formed.

[0013] In one or more embodiments, the current collector may be formed of a single sheet comprising a first bent region connecting the tab part to the connection part and a second bent region connecting the terminal part to the connection part.

[0014] In one or more embodiments, the sheet comprises a metal. The metal may comprise one or more of zinc, steel, nickel, copper or aluminium. In one or more embodiments, an outer surface of the current collector may be free from protrusions at the first and second weld regions.

[0015] In one or more embodiments, one or both of the first and second weld regions may comprise a recess, cut-out, groove or bevelled edge of the tab part and / or terminal part.

[0016] The connection part may extend along the third plane in a first direction away from the tab part and in a second direction away from the terminal part. In one or more embodiments, the tab part may extend in the second direction further than the connection part.

[0017] In one or more embodiments, the current collector may be for connecting a plurality of electrode tabs to an electrode terminal of a case. The current collector may comprise a plurality of tab parts, each tab part configured to be welded to a respective electrode tab.

[0018] In one or more embodiments, the current collector may be for connecting a pair of electrode tabs to an electrode terminal of a case. In one or more embodiments, the current collector may comprise a pair of tab parts, each tab part configured to be welded to a respective electrode tab.

[0019] According to a second aspect of the disclosure we provide a battery cell comprising: an electrode assembly having an electrode tab protruding from a side of the electrode assembly; a case housing the electrode assembly such that the electrode tab protrudes towards a first side of the case; an electrode terminal extending through a second side of the case, the second side extending perpendicular to the first side; and a current collector according the first aspect of the disclosure, or any one of its embodiments, wherein the tab part is welded to the electrode tab and the terminal part is connected to the electrode terminal to provide first and second current paths between the electrode tab and the electrode terminal.

[0020] According to a third aspect of the disclosure we provide a battery cell comprising: a plurality of electrode assemblies, each electrode assembly having a respective electrode tab protruding from a side of the electrode assembly; a case housing the plurality of electrode assemblies such that the respective electrode tabs protrude towards a first side of the case; an electrode terminal extending through a second side of the case, the second side extending perpendicular to the first side; and a current collector according to the first aspect of the disclosure and comprising a plurality of tab parts. Each tab part of the plurality of tab parts is welded to a respective electrode tab and the terminal part is connected to the electrode terminal to provide first and second current paths between the plurality of electrode tabs and the electrode terminal.

[0021] According to a fourth aspect of the disclosure we provide a method of manufacturing a current collector for connecting an electrode tab of an electrode assembly to an electrode terminal of a case in which the electrode assembly is received, the method comprising: providing a sheet comprising a tab part configured to be welded to the electrode tab, a terminal part configured to be connected to the electrode terminal of the case, and a connection part connecting the tab part to the terminal part; bending the sheet between the tab part and the connection part and between the terminal part and the connection part so that the tab part extends in a first plane, the terminal part extends in s second plane perpendicular to the first plane and the connection part extends in a third plane perpendicular to both the first plane and the second plane; welding a weld region of the tab part to a weld region of the terminal part.

[0022] Prior to welding the weld region of the tab part to the weld region of the terminal part, the method may comprise removing material from one or both of the weld region of the tab part and the weld region of the terminal part such that a weld seam formed as the weld region of the tab part is welded to the weld region of the terminal part does not protrude from an outer surface of either the terminal part or the tab part.

[0023] According to a fifth aspect of the disclosure we provide a method of manufacturing a battery cell comprising: manufacturing a current collector according to the method of fourth aspect of the disclosure or one of its embodiments; connecting an electrode terminal to the terminal part of the current collector; welding an electrode tab of an electrode assembly to the tab part of the current collector; placing the electrode assembly, the current collector and the electrode terminal into an open case; closing the case with a lid, wherein the electrode terminal extends through the lid.

[0024] Connecting the electrode terminal to the terminal part of the current collector may comprise welding the electrode terminal to the terminal part. In one or more embodiments, the steps of welding the weld region of the tab part to the weld region of the terminal part and welding the electrode terminal to the terminal part may be performed using the same welding apparatus.

[0025] According to a further aspect of the disclosure we provide a vehicle including a battery system comprising the battery cells as described herein or using battery cells manufactured with use of the method as described herein. The vehicle may comprise a battery electric vehicle and the battery system may be configured to provide motive power.

[0026] An additional aspect of the disclosure may comprise a battery system comprising the battery cells as described herein or using battery cells manufactured with use of the method as described herein, wherein the battery system comprises a battery energy storage system, such as grid-connected battery energy storage system. In other examples, the battery system comprises part of a trailer or roof-box for coupling to a vehicle.

[0027] While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that other embodiments, beyond the particular embodiments described, are possible as well.

[0028] The figures and Detailed Description that follow also exemplify various example embodiments. Various example embodiments may be more completely understood in consideration of the following Detailed Description in connection with the accompanying Drawings.

[0029] Brief Description of the Drawings

[0030] One or more embodiments will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 schematically shows a battery cell;

[0031] Figure 2 schematically shows a cross-sectional view of a portion of the battery cell shown in Figure 1;

[0032] Figure 3 schematically shows a current collector;

[0033] Figure 4 schematically shows the current collector of Figure 3 prior to certain manufacturing steps being carried out;

[0034] Figures 5 and 6 show close-up views of weld regions in the current collector of Figure 3 prior to being welded together;

[0035] Figures 7 and 8 show close-up views of weld regions in the current collector of Figure 3 after being welded together;

[0036] Figure 9 schematically shows another current collector;

[0037] Figure 10 schematically shows a further current collector;

[0038] Figure 11 schematically shows a method of manufacturing a current collector; and

[0039] Figure 12 schematically shows a method of manufacturing a battery cell.

[0040] Detailed Description

[0041] Figure 1 schematically shows a battery cell 100, also referred to hereinafter as 'cell 100', having a prismatic form factor. The cell 100 may have a substantially cuboidal shape, thereby having a rectangular profile, as shown in Figure 1. The cell 100 may comprise a casing 102, which may determine the general form factor of the cell 100 and may be configured (e.g., in its dimensions) for installation into a larger battery module, battery pack, or other battery assembly. The casing 102 may be rigid and resistant to external shocks or impacts, for example being made of metal such as aluminium or made of a high-density plastic.

[0042] The casing 102 may be formed from a plurality of sides joined together or may be formed of substantially one or two pieces, e.g., by extrusion, additive manufacturing (AM), or some other manufacturing technique. According to an example, the casing 102 may comprise a height (extending vertically as shown in Figure 1), a width (extending horizontally as shown in Figure 1), and a thickness (not visible).

[0043] The prismatic form factor for the cell 100, as defined substantially by the casing 102, may comprise two larger faces 102b (other larger face not visible) spaced apart by a relatively small distance in the thickness direction, and a plurality of comparatively smaller faces 102a, 102c, 102d, 102e bridging between the two larger faces 102b. The casing 102 may be formed by providing an open cuboidal shape and sealing the open face of the open cuboidal shape with a lid. For example, the lid may form the upper face 102a of the casing 102 (shown only as the top line in Figure 1).

[0044] Internal components of the cell 100 may be introduced into the casing 102 and then a lid 102a may be provided thereover and sealed in placed to thereby contain the internal components. The lid 102a may be attached in a substantially watertight fashion so as to contain liquid electrolyte in the cell 100, for example. The lid 102a may be provided with a vent, an injection port for injecting electrolyte, and / or other features, the details of which are outside the scope of the present disclosure.

[0045] In the illustrated example, provided on the casing 102 of the cell, and extending into the cell 100, are a pair of terminals 104. One of the terminals 104 may be an anode and the other may be a cathode. The terminals 104 may be riveted through the casing 102, e.g., through the lid 102a thereof, and provided with a gasket therearound to improve the watertight seal that the casing 102 may preferably provide. The terminals 104 may be made of any suitable conductive material, although the particular manufacture and installation of the terminals 104 is outside the scope of the present disclosure.

[0046] Both of the terminals 104 are shown installed at an upper face 102a of the casing 102 of the cell 100. However, it will be appreciated that either of the terminals 104 may instead be provided at any location around the casing 102 of the cell 100.

[0047] Figure 2 shows a cross-sectional view of the portion of the cell 100 indicated by the dotted box in Figure 1, revealing an internal space 103 within the casing 102. As shown in this figure, the cell 100 may comprise a terminal 104 that extends through the casing 102 and into the internal space 103 of the cell 100.

[0048] The cell 100 may further comprise an electrode assembly 106, which may be an electrode roll or an electrode stack, for example, comprising a plurality of sheets. The plurality of sheets may comprise an anode, a cathode, and a separator for separating the anode from the cathode, thereby providing the electrode assembly 106 with its ability to store electrical energy. The electrode assembly 106 may comprise, at a first side 106a thereof, an electrode tab 108 for electrically connecting to other components of the cell 100. In this example, the electrode assembly 106 has a substantially rectangular profile similar to that of the casing 102. Although not shown, the electrode assembly has a second side opposite to the first side 106a. There is also a third side 106b extending from the first side 106a to the second side, adjacent to the lid 102a and the terminals 104 extending through the lid 102a, and a fourth side (also not shown) opposite to the third side 106b. The electrode assembly 106 may also be considered as planar, or as extending along a plane through the cell 100.

[0049] The electrode tab 108 may be an extension from the roll or stack of one or more electrode sheets respectively, which may optionally be provided with notches, feathering, or some other processing to further facilitate the connection of the electrode tab 108 to other electrical components. In some variants, the entire length of the uncoated region of the electrode sheet forms the tab, without any notching being performed.

[0050] In some examples, the one or more electrode sheets have a plurality of sheet tabs, each sheet tab formed as an extension from the roll or stack of one or more electrode sheets. In particular, the sheet tabs may be formed from the foil that acts as a substrate in the electrode sheet. The foil may comprise, or consist of, a metal such as copper or aluminium. Typically, an anode (negative electrode) foil will comprise, or consist of, copper, whereas a cathode (positive electrode) foil will comprise, or consist of, aluminium.

[0051] All the sheet tabs of the plurality of sheet tabs may be joined together to form the electrode tab 108. In other words, the electrode tab 108 may be considered as a plurality of joined sheet tabs. The sheet tabs may be joined by a welding process or by some other suitable process which may involve the use of an electrically conductive glue, or a physical process such as clamping or crushing. For example, particularly if the terminal 104 is the positive terminal, the electrode tab 108 be formed from a plurality of aluminium foils joined together.

[0052] The cell 100 may be further provided with one or more spacers 110, some of which being electrical insulators, for appropriately spacing, retaining, etc. internal components of the cell 100 in their respective desired positions, and / or electrically insulating internal components of the cell 100 from each other or from the casing 102. It will be appreciated that the spacer 110 shown in Figure 2 is provided merely as a demonstrative example of the one or more spacers that may be included in the cell.

[0053] The electrode assembly 106 may be connected to the terminal 104 via a current collector 200. Figure 3 shows the current collector 200 in more detail. The current collector 200 comprises a tab part 202, a terminal part 204 and a connection part 206. The tab part 202 is configured to be welded to the electrode tab 108 and extends in a first plane. Meanwhile, the terminal part 204 is configured to be connected to the electrode terminal 104 and extends in a second plane perpendicular to the first plane. Lastly, the connection part connects the tab part 202 to the terminal part 204 and extends in a third plane perpendicular to both the first plane and the second plane.

[0054] When in use in a battery cell 100, as shown in Figure 2, a first current path Cl is formed between the electrode tab 108 and the electrode terminal 104 by the combination of the tab part 202, the connection part 206 and the terminal part 204. Further, the configuration of the current collector means that, in use, the first plane aligns with electrode assembly 106 such that the tab part 202 runs parallel to the electrode tab 108. Also, the second plane runs parallel to the lid 102a of the case 102 such that the electrode terminal 104 may extend through the terminal part 204 as it does the lid 102a. In this example, the terminal part 204 comprises an aperture 205 to receive the electrode terminal 104. In addition, the third plane runs parallel to a face 102e of the cell 100 such that the connecting part 206 may compliment the case 102 to provide additional protection of the electrode assembly, especially the electrode tab 108.

[0055] The tab part 202 comprises a first weld region 212 and the terminal part 204 comprises a second weld region 214. The current collector 200 is configured such that the two weld regions 212, 214 are suitably close to one another to be welded together to provide a second current path C2 between the electrode tab 108 and the electrode terminal 104. The provision of the second current path C2 in addition to the first current path Cl results in a reduction in the ohmic resistance of the current collector 200. In one or more examples, the first current path Cl and the second current path C2 are distinct current paths. For example, the material of the current collector through which the first current path Cl is provided may be physically separate to the material of the current collector through which the second current path C2 is provided at least at a location spaced from where the tab part 202 connects to the electrode tab 108 and the terminal part 204 connects to the terminal 104.

[0056] In this example, the tab part 202, the terminal part 204 and the connection part 206 are integrally formed. More particularly, the current collector 200 is formed of a single sheet 220 comprising a first bent region 222 connecting the tab part 202 to the connection part 206 and a second bent region 224 connecting the terminal part 204 to the connection part 206.

[0057] Figure 4 shows the sheet 220 prior to being bent to the shape shown in Figure 3. The dashed lines represent a first bend line 226 and a second bend line 228, which are the lines along which the sheet 220 is bent to form the first and second bent regions 222, 224 respectively.

[0058] The sheet 220 may be formed from any suitable material such as one or more of zinc, steel, nickel, copper and aluminium. The specific choice of material may further depend on whether the current collector is connecting the anode side or the cathode side of the cell 100. For example, a current collector to be used on the anode side may comprise copper whereas a current collector to be used on the cathode side may comprise aluminium.

[0059] Bending the sheet 220 along the first and second bend lines 226, 228 aligns the first weld region 212 with the second weld region 214, as shown in Figures 5 and 6.

[0060] In this example, the first and second weld regions 212, 214 each comprise a respective cut-out 232, 234 resulting in the tab part 202 and the terminal part 204 having a stepped edge. The cut-outs 232, 234 combine to provide a recess below an outer surface 230 of the current collector 200.

[0061] Figure 7 shows the first and second weld regions 212, 214 after they have been welded together. The dotted lines indicate where the edges of the tab part 202 and the terminal part 204 existed prior to a weld seam 216 being formed by the welding process.

[0062] The cut-outs 232, 234 result in the weld seam 216 being recessed below the outer surface 230 of the current collector 200. Figure 8 more clearly shows the weld seam 216 recessed below the outer surface 230.

[0063] By virtue of the recessed weld seam 216, the outer surface 230 is free from protrusions at the first and second weld regions 212, 214. Providing an outer surface 230 free from protrusions avoids any such protrusions interfering with the arrangement of the current collector 200 in the battery cell 100. For example, a protruding weld seam might clash with the spacer 110 (shown in Figure 2). Such a clash could result in the protruding weld seam damaging the spacer 110. Alternatively (or additionally), the protruding weld seam might be damaged by friction with the spacer 110. Accordingly, avoiding any such protrusion may improve the performance and / or durability of the cell 100.

[0064] In other examples, only one of the first and second weld regions may comprise a cutout. Alternatively, one or both of the first and second weld regions may comprise a recess, groove or bevelled edge of the tab part and / or terminal part.

[0065] In further examples, different approaches may be employed to provide an outer surface of the current collector that is free from protrusions at the first and second weld regions. For example, the weld seam may be machined to be flush with the outer surface, although this would add an additional step to the manufacturing process.

[0066] Figure 9 shows a current collector 300 that is similar to the current collector 200 shown in preceding figures except that the tab part 302 is longer relative to the connection part 306. More particularly, if the connection part 306 is considered as extending along the third plane in a first direction away from the tab part 302 and in a second direction away from the terminal part 304, the tab part 302 extends in the second direction further than the connection part 306. In other words, the tab part 302 may be considered as comprising an extended portion 308 that extends beyond the connection part 306 in the direction away from the terminal part 304.

[0067] The increased size of the tab part 302 relative to the connection part 306 may improve the ease with which the electrode tab 108 (shown in Figure 2) may be welded to the tab part 302.

[0068] Figure 10 shows a current collector 400 for connecting a pair of electrode tabs to an electrode terminal of a case. Rather than a single tab part (as provided in the current collectors 200, 300 shown in preceding figures) the current collector 400 comprises a pair of tab parts 402a, 402b. Each tab part 402a, 402b is configured to be welded to a respective electrode tab. (The tab part 402b is largely hidden in Figure 10 but, in this example, it is symmetrical to the other tab part 402a.)

[0069] In other examples, a current collector may be configured for connecting to more than two electrode tabs to an electrode terminal of a case. In such examples, the current collector would comprise a plurality of tab parts equal to the number of electrode tabs so that each electrode tab may be welded to a respective tab part. Figure 11 shows a method 500 of manufacturing a current collector, such as the current collector 200 shown in preceding figures. Accordingly, the method 500 is described with reference to the current collector 200 and the battery cell 100 (shown in Figures 1 to 8).

[0070] The method 500 comprises providing 502 a sheet 220 comprising a tab part 202 configured to be welded to an electrode tab 108, a terminal part 204 configured to be connected to an electrode terminal 104 of a case 102, and a connection part 206 connecting the tab part 202 to the terminal part 204. Next, the method 500 comprises bending 504 the sheet 220 between the tab part 202 and the connection part 206 and between the terminal part 204 and the connection part 206 so that the tab part 202 extends in a first plane, the terminal part 204 extends in s second plane perpendicular to the first plane and the connection part 206 extends in a third plane perpendicular to both the first plane and the second plane. The method 500 comprises a further step of welding 506 a weld region 212 of the tab part 202 to a weld region 214 of the terminal part 204.

[0071] Any suitable method and means may be used for bending 504 the sheet 220. For example, a progressive die stamping apparatus and related stamping method may be used.

[0072] Similarly, any suitable method and means may be user for welding 506 the weld regions 212, 214 together. Optionally, a laser welding process and apparatus may be used. A suitable laser welding technique is laser beam welding (LBW). Other suitable welding techniques may include tungsten inert gas (TIG) welding and metal inert gas (MIG) welding.

[0073] Prior to welding 506 the weld region 212 of the tab part 202 to the weld region 214 of the terminal part 204, the method may additionally comprise removing material from one or both of the weld region 212 of the tab part 202 and the weld region 214 of the terminal part 204 such that a weld seam 216 formed as the weld region 212 of the tab part 202 is welded to the weld region 214 of the terminal part 204 does not protrude from an outer surface 230 of either the terminal part 204 or the tab part 202. The removal of material may form a recess, cut-out, groove or bevelled edge of the tab part and / or terminal part.

[0074] The method 500 may form part of a method 600 of manufacturing a battery cell 100, as shown in Figure 12. The method 600 comprises: manufacturing 500 the current collector 200; welding 602 an electrode terminal 104 to the terminal part 204 of the current collector 200; welding 604 an electrode tab 108 of an electrode assembly 106 to the tab part 202 of the current collector 200; placing 606 the electrode assembly 106, the current collector 200 and the electrode terminal 104 into an open case 102; and closing the case 102 with a lid 102a, wherein the electrode terminal 104 extends through the lid 104.

[0075] In some examples of the method 600, connecting 602 the electrode terminal 104 to the terminal part 204 of the current collector 200 comprises welding the electrode terminal 104 to the terminal part 104. In such examples, welding 506 the weld region 212 of the tab part 202 to the weld region 214 of the terminal part 214 and welding the electrode terminal 104 to the terminal part 204 may be performed using the same welding apparatus. This means that both welding steps can be performed at the same station in the manufacturing line, streamlining the process and reducing the cost of the manufacturing line.

[0076] Connecting 602 the electrode terminal 104 to the terminal part 204 may additionally or alternatively comprise physically fixing the electrode terminal 104 to the terminal part, such as by providing a riveted connection. Other suitable connecting means may include the use of an electrically conductive glue, for example.

[0077] In one example, one or more instructions or steps discussed herein are automated. Thus, performing the method may include controlled operation of an apparatus, system, and / or process using computers and / or mechanical / electrical devices without the necessity of human intervention, observation, effort and / or decision.

[0078] In this specification, example embodiments have been presented in terms of a selected set of details. However, a person of ordinary skill in the art would understand that many other example embodiments may be practiced which include a different selected set of these details. It is intended that the following claims cover all possible example embodiments.

Claims

CLAIMS1. A current collector (200) for connecting an electrode tab (108) of an electrode assembly (106) to an electrode terminal (104) of a case (102) in which the electrode assembly (106) is received, the current collector (200) comprising: a tab part (202) configured to be welded to the electrode tab (108) and extending in a first plane; a terminal part (204) configured to be connected to the electrode terminal (104) of the case (102) and extending in a second plane perpendicular to the first plane; and a connection part (206) connecting the tab part (202) to the terminal part (204) to provide a first current path between the electrode tab (108) and the electrode terminal (104) of the case (102), the connection part (206) extending in a third plane perpendicular to both the first plane and the second plane, wherein the tab part (202) comprises a first weld region (212) and the terminal part (204) comprises a second weld region (214), the first and second weld regions (212, 214) welded together to provide a second current path between the electrode tab (108) and the electrode terminal (104) of the case (102).

2. The current collector (200) of claim 1, wherein the tab part (202), the terminal part (204) and the connection part (206) are integrally formed.

3. The current collector (200) of claim 2, wherein the current collector (200) is formed of a single sheet (220) comprising a first bent region (222) connecting the tab part (202) to the connection part (206) and a second bent region (224) connecting the terminal part (204) to the connection part (206).

4. The current collector (200) of claim 3, wherein the sheet (220) comprises a metal, the metal optionally comprising one or more of zinc, steel, nickel, copper or aluminium.

5. The current collector (200) of any preceding claim, wherein an outer surface (230) of the current collector (200) is free from protrusions at the first and second weld regions (212, 214).

6. The current collector (200) of any preceding claim, wherein one or both of the first and second weld regions (212, 214) comprises a recess, cut-out (232, 234), groove or bevelled edge of the tab part (202) and / or terminal part (204).

7. The current collector (300) of any preceding claim, wherein the connection part (306) extends along the third plane in a first direction away from the tab part (302) and in a second direction away from the terminal part (304), and wherein the tab part (302) extends in the second direction further than the connection part (306).

8. The current collector (400) of any preceding claim, wherein the current collector (400) is for connecting a plurality of electrode tabs to an electrode terminal (104) of a case (102), and wherein the current collector (400) comprises a plurality of tab parts (402a, 402b), each tab part configured to be welded to a respective electrode tab.

9. A battery cell (100) comprising: an electrode assembly (106) having an electrode tab (108) protruding from a side (106a) of the electrode assembly (106); a case (102) housing the electrode assembly (106) such that the electrode tab (108) protrudes towards a first side (102e) of the case (102); an electrode terminal (104) extending through a second side (102a) of the case (102), the second side (102a) extending perpendicular to the first side (102e); and a current collector (200) according to any of claims 1 to 7, wherein the tab part (202) is welded to the electrode tab (108) and the terminal part (204) is connected to the electrode terminal (104) to provide first and second current paths between the electrode tab (108) and the electrode terminal (104).

10. A method of manufacturing a current collector (200) for connecting an electrode tab (108) of an electrode assembly (106) to an electrode terminal (104) of a case (102) in which the electrode assembly (106) is received, the method comprising: providing a sheet (220) comprising a tab part (202) configured to be welded to the electrode tab (108), a terminal part (204) configured to be connected to the electrode terminal (104) of the case (102), and a connection part (206) connecting the tab part (202) to the terminal part (204); bending the sheet (220) between the tab part (202) and the connection part (206) and between the terminal part (204) and the connection part (206) so that the tab part (202) extends in a first plane, the terminal part (204) extends in a second plane perpendicular to the first plane and the connection part (206) extends in a third plane perpendicular to both the first plane and the second plane; welding a weld region (212) of the tab part (202) to a weld region (214) of the terminal part (204).

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