SE2350706A1

SE2350706A1 - Apparatus and method for shaping electrode tabs

Info

Publication number: SE2350706A1
Application number: SE2350706A
Authority: SE
Inventors: Hong Hyeon Lee; Julian Alexander Sulik
Original assignee: Northvolt Ab
Priority date: 2023-06-09
Filing date: 2023-06-09
Publication date: 2024-12-10
Also published as: WO2024251949A1

Abstract

There is disclosed herein a process (400) for shaping electrode tabs (112) extending from an edge of an electrode assembly (110), comprising bending (410), in a first direction, an inner section (112b) of the electrode tabs 112 proximal the edge of the electrode assembly (110), and bending (420), in a second direction opposite the first direction, an outer section (112c) of the electrode tabs (112), the outer section (112c) being further from the edge of the electrode assembly (110) than the inner section (110b). There is further disclosed herein an electrode assembly (110) having tabs (112) shaped according to such a process (400) and a battery cell (100) comprising such an electrode assembly (110), a method for manufacturing such a battery cell (100), an apparatus (200) for performing such a process (400), and a battery cell (100) having an electrode assembly (110) with shaped tabs (112).

Description

Technical Field id="p-1" id="p-1" id="p-1"

[0001]The present disclosure relates to the manufacture of a battery cell, and an apparatus therefor. More particularly, the present disclosure relates to a process and apparatus for shaping electrode tabs, and battery cells comprising electrode assemblies with shaped electrode tabs.

Background id="p-2" id="p-2" id="p-2"

[0002]ln addressing climate change, there is an increasing demand for rechargeable batteries, e.g. to enable electrification of transportation and to supplement renewable energy. Currently, lithium-ion batteries are becoming increasingly popular. They represent a type of rechargeable battery in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging. id="p-3" id="p-3" id="p-3"

[0003]As the demand for rechargeable batteries increases, more and more focus is being placed on production speed and cost. To achieve an effective production of rechargeable batteries, the design of the batteries as well as their manufacturing process can be optimized. id="p-4" id="p-4" id="p-4"

[0004] Batteries (also referred to as 'battery cells' or 'secondary cells') may comprise electrode stacks, being a series of layers of electrode sheets (i.e., anode sheets and cathode sheets) having a separator sheet arranged therebetvveen. To connect the electrode stack to a current collector, electrode tabs protrude from corresponding sheets of the electrode stack (e.g., cathode sheets for connecting to a cathode current collector). The tabs extend from a side of the electrode stack and are compressed and/or welded together to thereby electrically interconnect the tabs as part of a pre-welding process. Thereafter, the pre-welded tabs are welded to a current collector.

Summary id="p-5" id="p-5" id="p-5"

[0005]The present disclosure aims to provide improved secondary cells and parts thereof, through improved methods of manufacture. The improvements may be in crush resistance, energy performance, manufacturing efficiency, and assembly simplification, among others. id="p-6" id="p-6" id="p-6"

[0006]ln particular, according to an aspect of the present disclosure, there is provided a process for shaping electrode tabs extending from an edge of an electrode assembly. The process comprises bending, in a first direction, an inner section of the electrode tabs proximal to the edge of the electrode assembly, and bending, in a second direction opposite the first direction, an outer section of the electrode tabs, the outer section being further from the edge of the electrode assembly than the inner section. As used herein, the term 'electrode tabs' is intended to include both notched and notchless electrode assemblies, i.e., wherein the electrode tabs are formed by extensions from electrode sheets or layers of the electrode assembly. id="p-7" id="p-7" id="p-7"

[0007]The bending in the first direction may be along a stacking direction of the electrode assembly and, in some examples, may be a substantial flattening of the electrode tabs against the edge of the electrode assembly. Preferably, the bending in the first direction results in the inner section of the electrode tabs being substantially flat against the edge of the electrode assembly. id="p-8" id="p-8" id="p-8"

[0008]The bending in the first and second directions may be applied to the entirety of the electrode tabs, or directed at only the inner or outer sections thereof (respectively), depending on the implementation. That is, viewed from one perspective, the bending in the first direction may comprise bending the electrode tabs to thereby bend the inner section in the first direction, and the bending in the second direction may comprise bending the electrode tabs to thereby bend the outer section in the second direction. id="p-9" id="p-9" id="p-9"

[0009]The bending in the second direction may be part of a laminating and/or pre-welding process, and the outer sections of the electrode tabs may be the ends of the electrode tabs, in some examples. Alternatively, the outer sections of the electrode tabs may be some intermediate portion of the electrode tabs between the inner sections of the electrode tabs and the ends of the electrode tabs. lndeed, the electrode tabs may comprise further bends formed in further intermediate sections between the inner sections of the electrode tabs and the ends of the electrode tabs. id="p-10" id="p-10" id="p-10"

[0010]|t will be appreciated that the bending in the second direction is configured to preserve the bend formed by the bending in the first direction. For example, if the bending in the second direction is a laminating of the ends of the electrode tabs together, against a first Iamination surface, then the first bending may be performed by moving a first shaping surface beyond said first Iamination surface, in the first direction - i.e., the first bend extends further in the first bending direction than the Iamination moves in the other direction, so as to preserve the bend in the electrode tabs. id="p-11" id="p-11" id="p-11"

[0011]The first bending and the second bending may be performed one after another, or at the same time, i.e., simultaneously or contemporaneousiy, depending on the implementation. lt may expedite a manufacture of the battery cell to perform steps at the same time. However, it may be preferred to perform a bending of at least the inner sections of the electrode tabs before a lamination/pre-welding such that the ends of the electrode tabs can move relative to each other to accommodate the bending before they are laminated together, otherwise there may be a risk of delamination of the ends of the electrode tabs. id="p-12" id="p-12" id="p-12"

[0012] By shaping the tabs according to such a process, the performance of the battery cell during a crush along its side can be improved. For example, bending the electrode tabs in a first direction (e.g., along the stacking direction), at a location proximal to the electrode assembly, advantageously forms a protective wall, i.e., formed of the material of the electrode tabs themselves, that is arranged at least between the current collector and the electrode assembly. Therefore, during a crush along the side of the battery cell where the current collector is arranged, the risk that the current collector penetrates the electrode assembly and causes a short-circuit is reduced. id="p-13" id="p-13" id="p-13"

[0013]The bending in the first directing is preferably a ﬂattening of the inner sections of the electrode tabs against the edge of the electrode assembly, such that a protective wall/surface is formed that is substantially orthogonal to the current collector. id="p-14" id="p-14" id="p-14"

[0014]|n some example embodiments, the protective wall formed by the bending in the first direction further comprises separator layers, these separator layers being protruding from the electrode assembly between the electrode tabs and bent along with the electrode tabs, in the first direction, during the bending in the first direction. id="p-15" id="p-15" id="p-15"

[0015]Synergistically, the bending in the second direction provides an advantageous 'spine' shape, or 'ridge' shape in the electrode tabs that increases the total length thereof in the space between the edge of the electrode assembly and the current collector. This additional length serves to reduce the tension in the electrode tabs, such that, during a crush event, the risk of the electrode tabs tearing and causing a short-circuit is reduced. id="p-16" id="p-16" id="p-16"

[0016]lt will be appreciated that further bends could be applied to the electrode tabs during the shaping process, to further increase the protection provided. id="p-17" id="p-17" id="p-17"

[0017]The process of shaping the electrode tabs may be performed by an apparatus having appropriately configured surfaces moving against the electrode tabs, or by moving the electrode tabs against the surfaces. For example, the bending of the inner section of the electrode tabs may comprise moving the electrode assembly in the second direction to bring the inner section of the electrode tabs into contact with a shaping surface, or moving a shaping surface in the first direction to bring the shaping surface into contact with the inner section of the electrode tabs. id="p-18" id="p-18" id="p-18"

[0018]According to an aspect of the present disclosure, the apparatus comprises a holder for receiving the electrode assembly, a first surface configured to bend the inner section of the electrode tabs in the first direction, and a second surface configured to bend the outer section of the electrode tabs in the second direction. id="p-19" id="p-19" id="p-19"

[0019]|n an example implementation of such an apparatus, the apparatus comprises a shaping tool comprising the first surface, and an anvil comprising the second surface. The shaping tool may be configured with a tapered edge extending perpendicular to the length of the electrode tabs, as with conventional tools used for securing electrode tabs during a pre-welding process. The shaping tool may be configured to move separately to the anvil, or may be formed as, e.g., a protruding ledge protruding from the anvil. ln the latter case, the protruding ledge may preferably protrude 1 to 5 mm from the anvil, preferably 1 to 2 mm. id="p-20" id="p-20" id="p-20"

[0020]ln an example, the apparatus further comprises a hammer, comprising a third surface configured to be brought against the second surface of the anvil. The hammer (which may also be referred to as a 'horn') and the anvil may be respectively configured to laminate the ends of the electrode tabs together and/or apply a pre-weld to the electrode tabs, e.g., via ultrasonic welding. Accordingly, the hammer and/or the anvil may comprise a surface profiling for increasing the contact surface area with the electrode tabs. id="p-21" id="p-21" id="p-21"

[0021]According to a further aspect of the present disclosure, there is provided a battery cell comprising an electrode assembly, wherein electrode tabs extending from an edge of the electrode assembly are shaped according to the shaping process substantially as described above. id="p-22" id="p-22" id="p-22"

[0022]According to a further aspect of the present disclosure, a method of manufacturing such a battery assembly comprises shaping electrode tabs extending from each of opposite sides of an electrode assembly, according to the process as described above, welding the electrode tabs to respective current collectors extending along said sides of the electrode assembly, and arranging the electrode assembly and the current collectors into an open end of a casing for the battery cell, wherein said sides of the electrode assembly are arranged perpendicular to the open end of the casing. id="p-23" id="p-23" id="p-23"

[0023]The battery cell may preferably be a prismatic cell having a length greater than its height, and a height greater than its width, wherein the electrode assembly has similar proportions. The height of the electrode assembly may be referred to as the 'short side' of the electrode assembly.

Current collectors are thus arranged along each of the short sides of the electrode assembly, from which the electrode tabs extend. The open end of the casing into which the electrode assembly and current collectors are inserted is one of the long sides of the cell. Accordingly, the height of the electrode assembly may be advantageously increased, thereby allowing for a greater energy density of the battery cell. id="p-24" id="p-24" id="p-24"

[0024]Viewed from one perspective, there is provided, according to aspects of the present disclosure, a battery cell comprising an electrode assembly having electrode tabs extending from the edge thereof that are shaped, and attached to a current collector. That is, the electrode tabs have a shaping wherein a first section of the electrode tabs proximal the edge of the electrode assembly is bent in a first direction, and a second section of the electrode tabs, further from the edge of the electrode assembly than the first section, is bent in a second direction opposite the first direction. id="p-25" id="p-25" id="p-25"

[0025]As discussed at least briefly above, the first bend advantageously flattens the parts of the electrode tabs immediately protruding from edge of the electrode assembly against said edge, thereby providing additional protection to the electrode assembly from an intrusion thereinto by the current collector. The second bend then serves to provide a low-tension connection to the current collector and thus reduces the risk of tearing of the electrode tabs during a crush event, and reduces the transfer of vibrations and/or heat during a welding of the ends of the electrode tabs. The second bend further allows for a connection/attachment of the electrode tabs along a direction that is not the first direction, e.g., along a length direction of the electrode assembly, along which a connection part of the current collector may extend. id="p-26" id="p-26" id="p-26"

[0026]The electrode assembly may typically further comprise separator layers, e.g., formed from one or more separator sheets. According to a preferred example implementation of the present disclosure, a protruding section of a plurality of the separator layers is bent in the first direction to thereby provide an insulating wall between the current collector and the electrode assembly. id="p-27" id="p-27" id="p-27"

[0027]Thus, not only a mechanical protection is provided (i.e., by the inner sections of the electrode tabs being bent over in the first direction) but also an electrical protection, thus further reducing the risk of short circuiting within the electrode assembly caused by opposing polarities of electrode layers coming into contact with one another. By bending (and preferably substantially flattening) the inner sections of the electrode tabs in the first direction, it will be appreciated that the protruding portions of the separator layers may be bent as well, thus forming the insulating wall. id="p-28" id="p-28" id="p-28"

[0028]lt will be appreciated that only some of the electrode tabs may comprise the aforementioned shaping. For example, only the electrode tabs extending from electrode layers that are in the vicinity/neighborhood of the current collector, in the stacking direction, may comprise the shaping, and electrode layers beyond the current collector in the stacking direction (in first direction) may correspond substantially to a shaping formed by prior art approaches. id="p-29" id="p-29" id="p-29"

[0029]The electrode tabs may, for example, be attached to the current collector on a first side thereof, and the shaped electrode tabs may thus extend past the first side with the first bend and be bent back on themselves with the second bend to be attached to the current collector. ln a preferred example, the first side of the current collector may be 8 to 10 mm from a top of the electrode stack (in the stacking direction), and preferably 9.3 to 9.5 mm. id="p-30" id="p-30" id="p-30"

[0030]As a result of the first bend and the second bend, the first bend and the second bend of the electrode tabs may form a substantially serpentine shape, i.e., along the length of the electrode tabs. id="p-31" id="p-31" id="p-31"

[0031]Accordingly, aspects of the present disclosure provide improvements in energy performance, manufacturing efficiency, and assembly simplification, particularly for the closing of the casings of cylindrical secondary cells, among other advantages which will be made clear through the below description of specific embodiments.

Brief Description of the Drawings id="p-32" id="p-32" id="p-32"

[0032]One or more embodiments of the present disclosure will be described, by way of example only, and with reference to the following figures, in which: id="p-33" id="p-33" id="p-33"

[0033]Figure 1A schematically shows a perspective view of a battery cell according to aspects of the present disclosure; id="p-34" id="p-34" id="p-34"

[0034]Figure 1B shows a top view of the battery cell shown in figure 1A; id="p-35" id="p-35" id="p-35"

[0035]Figure 1C shows a schematic cross-sectional view of the battery cell shown in figures 1A and 1B, taken along the line A-A as shown in figure 1B; id="p-36" id="p-36" id="p-36"

[0036]Figure 1D shows a schematic cross-sectional view of the region B of the battery cell as shown in figure 1B, taken along the line C-C as shown in figure 1C; id="p-37" id="p-37" id="p-37"

[0037]Figure 2A shows a laminating of electrode tabs according to prior art approaches; id="p-38" id="p-38" id="p-38"

[0038]Figure 2B shows a shaping and laminating of electrode tabs according to aspects of the present disclosure; id="p-39" id="p-39" id="p-39"

[0039]Figure 3A schematically shows a side view of a pre-welding process being applied to electrode tabs, before shaping and laminating of the electrode tabs; id="p-40" id="p-40" id="p-40"

[0040]Figure 3B schematically shows the same side view as figure 3A, after shaping and laminating of the electrode tabs; id="p-41" id="p-41" id="p-41"

[0041]Figure 4 illustrates a two-part pre-welding process according to aspects of the present disclosure; and id="p-42" id="p-42" id="p-42"

[0042]Figures 5A to 5C show various examples of how to implement the two- part pre-welding process as shown in figures 3A and 3B and illustrated in figure 4.

Detailed Description id="p-43" id="p-43" id="p-43"

[0043]The present disclosure is described in the following by way of a number of illustrative examples. lt will be appreciated that these examples are provided for illustration and explanation only and are not intended to be limiting on the scope of the present disclosure. lnstead, the scope of the present disclosure is defined by the appended claims. id="p-44" id="p-44" id="p-44"

[0044]Furthermore, although embodiments be presented individually for the sake of focused discussion of particular features, it will be recognized that the present disclosure also encompasses combinations of the embodiments described herein. id="p-45" id="p-45" id="p-45"

[0045]Figure 1A schematically shows a battery cell 100 according to aspects of the present disclosure, also referred to herein as simply a 'cell 100". ln the illustrated example, a prismatic battery cell 100 is shown having a cuboidal casing 102 that is longer that it is tall, and taller than it is wide. The height of the cell 100 may be referred to as the 'short side' of the cell 100. id="p-46" id="p-46" id="p-46"

[0046]lt will be appreciated that the illustrated prismatic cell 100 is purely illustrative and that the presently disclosed aspects could, with appropriate adaptations, be applied to cylindrical secondary cells. id="p-47" id="p-47" id="p-47"

[0047]The cell 100 has terminals 104 on a same side, i.e., the top side of the cell 100 as illustrated, a failure vent 106 for venting gases from the cell 100, and an injection port 108 for introducing an electrolyte, also shown in figure 1B. The failure vent 106 and the injection port 108 are not discussed in detail herein and are not shown in figure 1C. id="p-48" id="p-48" id="p-48"

[0048]Figure 1C shows the connection of the terminals 104 to an electrode stack 110 (which may also be referred to as an 'electrode assembly') comprised in the cell 100, via current collectors 114. Particularly, the current collectors 114 are arranged around corners of the electrode stack 110 such that a first extension of each of the current collectors 114 extends along the top side of the electrode stack 110 (as illustrated) to connect to a terminal 104 electrically and mechanically on the top side of the cell 100. A second extension of each of the current collectors 114, angled relative to the first extension (i.e., at substantially 90 degrees), extends along the short side of the electrode stack 110 (i.e., the height) and is connected to the electrode stack 110 via electrode tabs 112 (also referred to herein as simply 'tabs 112') extending from the short sides of the electrode stack 110, as shown in more detail in figure 1D. id="p-49" id="p-49" id="p-49"

[0049]The arrangement of the current collectors 114 on the sides of the electrode stack 110, rather than, e.g., on an upper side thereof, allows for the height of the electrode stack to be increased and thus improves the energy density of the cell 100. id="p-50" id="p-50" id="p-50"

[0050]The cell 100 further comprises a number of spacers/insulators 116 configured to properly space the internal components of the cell 100 from one another and/or electrically and/or thermally insulate the internal components from the casing 102, which may be made from metal such as nickel-plated steel or aluminum, depending on the implementation of the aspects of the present disclosure. id="p-51" id="p-51" id="p-51"

[0051]During assembly of the cell 100, the upper end of the casing 102 may be a lid that is arranged to close an opening in the casing 102 after arrangement of the electrode stack 110 and the current collectors 114, welded thereto, into the opening of the casing 102. id="p-52" id="p-52" id="p-52"

[0052]Figure 1D schematically shows the connection of the electrode stack 110 to the current collector 114 in more detail, showing the region B indicated in figure 1B, taken along the cross-sectional line C-C as shown in figure 1C. id="p-53" id="p-53" id="p-53"

[0053]As shown in figure 1D, the electrode stack 110 is formed of a pair of stacks 110 having a stacking direction along the width of the cell 100. From an edge of the electrode stacks 110, a plurality of electrode tabs 112 extend. The tabs 112 may be extensions of electrode sheets in the stack 110 (e.g., cathode or anode sheets) or may be attached to the electrode sheets, depending on the implementation. id="p-54" id="p-54" id="p-54"

[0054]The tabs 112 correspond to a single polarity of the electrode stack 110, such as the cathode or the anode, such that their connection together allows for a common cathode or anode connection. For example, if the tabs 112 are extensions from cathode sheets in the electrode stacks 110, then the connection of the cathode sheets to the current collector 114 provides a 11 cathode connection point at the terminal 104 to which said current collector 114 is connected. id="p-55" id="p-55" id="p-55"

[0055]The current collector comprises an attachment plate 114a which has an extension in the length direction of the cell 100 to thereby provide a surface to which the e|ectrode tabs 112 can be welded. ln the i||ustrated example, the tabs 112 from each of the pair of e|ectrode stacks 110 are welded to the outer surfaces of the attachment plates 114a, i.e., the surfaces which face the casing 102. id="p-56" id="p-56" id="p-56"

[0056]The tabs comprise a first section 112a, which may also be referred to as a converging region, starting from the edge of the e|ectrode stacks 110. The inner section 112a is the section of the tabs 112 proximal the edge of the e|ectrode stacks 110. id="p-57" id="p-57" id="p-57"

[0057]The tabs 112 further comprise an end portion 112e which is further from the edge of the e|ectrode stack (along the length of the tabs 112) and connected to the attachment plate 114a of the current collector. The end portion 112e of the tabs 112 may be pre-welded together before attachment to the current collector, e.g., by laminating and/or pre-welding the end portion 112e of the tabs together. Laminating the end portion 112e of the e|ectrode tabs 112 may comprise compressing or otherwise flattening the end portion 112e of the tabs 112 substantially orthogonally to the stacking direction of the e|ectrode stack 110 (corresponding to the stacking direction of the tabs 112 as i||ustrated). id="p-58" id="p-58" id="p-58"

[0058]The shape of the tabs 112 is purely schematic in figure 1D. An example of attaching e|ectrode tabs 112 to the current collector 114 according to a prior art approach is shown in figure 2A, and an example of a shaping of e|ectrode tabs 112 according to aspects of the present disclosure is shown in figure 2B. id="p-59" id="p-59" id="p-59"

[0059]As shown in figure 2A, a conventional approach to attaching e|ectrode tabs 112 comprises pressing and pre-welding the ends of the e|ectrode tabs 112 together before welding the pre-welded outer/end section 112e to the 12 current collector 114 (particularly, to an attachment plate 114a of the current collector 114). id="p-60" id="p-60" id="p-60"

[0060]Such an approach may be followed, e.g., in prismatic cells having side current collectors, with a view to conserving electrode material. However, it is realized as a part of the present disclosure that this approach to attaching electrode tabs 112 to the current collector 114 leaves the electrode stack 110 more vulnerable to damage during a crush event along the side of the cell 100, or from an other side of the current collector 114 viewed from the electrode stack 110, where the current collector 114 is at risk of being pushed into the electrode stack 110. id="p-61" id="p-61" id="p-61"

[0061]According to the conventional approach shown in figure 2A, it can be seen that the inner sections 112a of the electrode tabs 112 are substantially spread out, especially in the region of the current collector 114 (and the pre- welded outer region 112e of the electrode tabs 112). As a result, when the attachment plate 114a of the current collector 114 and/or the pre-welded outer portion 112e of the tabs 112 is pushed into the electrode stack 110 during a crush event, there is little hinderance to the incursion into the electrode stack 110. id="p-62" id="p-62" id="p-62"

[0062]Figure 2B shows an example implementation of the presently disclosed technique, wherein an inner section 112b of the electrode tabs 112, proximal to the edge of the electrode stack 110 is bent in a first direction (i.e., upwards as shown in the figure), and an outer section 112c of the electrode tabs 112 is bent in a second direction opposite the first direction (i.e., downwards). ln an example process of forming this shaping, the first bend and the second bend may be formed through respective bending steps, before pre-welding of the ends 112e of the electrode tabs 112, or the second bend may be formed as part of a same step as the lamination/pre-welding of the ends 112e of the electrode tabs 112. id="p-63" id="p-63" id="p-63"

[0063]lt can be seen in figure 2B that not all of the tabs 112 are shaped in this way. Of the tabs 112 that are connected to the current collector 114, it can be seen that at least the tabs 112 level with and below the current collector 114 (in the stacking direction) have this shaping. Accordingly, for 13 these shaped tabs 112, being attached to the current collector 114 on a first side thereof (i.e., an upper side of the attachment plate 114a), the shaped tabs 112 extend past the first side (in the stacking direction) with the first bend and are bent back on themselves with the second bend to be attached to the attachment plate 114a of the current collector 114. id="p-64" id="p-64" id="p-64"

[0064]ln this example at least, the shaped tabs 112 form a substantially serpentine shape. By bending the inner section 112b of the tabs 112 in a first direction, it can be seen from the zoomed portion of the figure 1B that the electrode stack 110 is not easily entered by the current collector 114 and/or pre-welded ends 112e of the tabs 112, as a protective wall has been formed by the bent inner sections 112b of the shaped tabs 112. These shaped tabs 112 present a substantially orthogonal surface to the current collector 114. id="p-65" id="p-65" id="p-65"

[0065]While a more open part of the electrode stack 110 still exists, i.e., substantially above the attachment plate 114a in the stacking direction, this is of less concern as the current collector 114 is not being pushed into this part of the electrode stack 110 during a side crush event. id="p-66" id="p-66" id="p-66"

[0066]lt can be seen that the electrode stack 110 comprises anode sheets 110a, cathode sheets 110c, and separator sheets 110s (or layers) arranged therebetvveen. ln the figures, the separator sheets 110s are shown as being individual sheets, which may be the case with a laminated electrode stack 110. However, in other example implementations, the electrode stack 110 may comprise one or more longer separator sheets 110s that are zig-zag folded to form layers between which the anode sheets 110a and cathode sheets 110c are arranged. id="p-67" id="p-67" id="p-67"

[0067]ln the illustrated example, the cathode sheets 110c extend further from the electrode stack 110 to thereby from the electrode tabs 112. However, it will be appreciated that the electrode tabs 112 may instead be additional conductive sheets attached to the ends of the cathode sheets 112c. lt will further be appreciated that the presently described arranged may be inverted such that the anode sheets 110a extend to form electrode tabs 112, and this may be the case on an opposite edge of the electrode stack 110 than that illustrated in figure 2B. 14 id="p-68" id="p-68" id="p-68"

[0068]Separator sheets 110s may conventionally extend out from the electrode stack 110 further than the anode sheets 110a. Thus, by bending the inner sections 112i of the electrode tabs 112, that is proximal the edge of the electrode stack 110, the separator sheets can also be bent and shaped in the first direction along with the bent inner sections 112i of the electrode tabs 112. id="p-69" id="p-69" id="p-69"

[0069]According|y, the separator sheets 110s can effectively block an incursion of the current collector 114 and/or pre-welded ends 112e of the tabs 112 into the electrode stack 110 during a crush event, by forming an insulating wall (i.e., mechanically and/or electrically insulating). Accordingly, a risk of short circuit during a side crush event is advantageously reduced by shaping the electrode tabs 112 according to the presently disclosed techniques. id="p-70" id="p-70" id="p-70"

[0070]The approach according to aspects of the present disclosure provides yet a further advantage, which can be readily appreciated from the illustration of figure 2B. Namely, it will be appreciated that the bending of the tabs 112 provides an additional length to the tabs 112 between the edge of the electrode stack 110 and the attachment plate 114a of the current collector 114. This additional length, formed as a first and second bend, thus provides a tolerance for accommodating motion of the current collector 114 without tearing the tabs 112. id="p-71" id="p-71" id="p-71"

[0071]lf the ends 112e of the electrode tabs 112 is to be welded using heat, then it can be seen that the increased length of the tabs 112 can allow for a lesser transfer of such heat to the electrode stack 110. Moreover, if the ends 112e of the electrode tabs 112 are to be pre-welded through, e.g., ultrasonic welding, then it can be seen that vibrations from such a process can be advantageously dampened by the first and second bends. id="p-72" id="p-72" id="p-72"

[0072]Two bends are shown in figure 2B, i.e., a bend upwards in the inner section 112b of the tabs 112, from and along the edge of the electrode stack 110, and a bend downwards in the outer section 112c of the tabs 112, back on themselves and towards an end section 112e of the tabs 112. However, it will be appreciated that, in other example implementations, more bends may be included, which may further enhance the advantageous effects described in association with the bends. id="p-73" id="p-73" id="p-73"

[0073]An example apparatus for shaping electrode tabs 112 according to aspects of the present disclosure is shown schematically in figures 3A and 3B. According to this example, the first bend is applied by a first surface 202, which may also be referred to as a "shaping surface', which is on an upper side of a shaping tool 230, which may be a shaped metal 'finger' tool or the like, according to an example. The second bend is applied by a second surface 206, which is on a lower side of a hammer 210. id="p-74" id="p-74" id="p-74"

[0074]ln this example, the application of the second bend is through motion of the hammer 210 against an anvil 220, which further acts to laminate the ends of the electrode tabs 112 together. ln a further example, the ends of the electrode tabs 112 may also be welded together by the hammer 210 and the anvil using, e.g., ultrasonic welding. id="p-75" id="p-75" id="p-75"

[0075]The electrode assembly 110 is received and held in a holder 240, which is arranged relative to the hammer 210, anvil 220, and shaping tool 230 in order for the bends to be properly applied. The holder 240, hammer 210, anvil 220, and shaping tool 230 may be moved relative to each other in any appropriate manner so as to bend the electrode tabs 112 in a first direction, and a second direction, i.e., such that an inner section of the electrode tabs 112 proximal to the electrode assembly 110 is bent in the first direction. id="p-76" id="p-76" id="p-76"

[0076]A process 400 for shaping the electrode tabs 112 is illustrated in figure 4 as a two-part shaping process 400, comprises a first part (step 410) wherein the electrode tabs 112 are bent such that an inner section of the electrode tabs 112 are bent in a first direction, and a second part (step 420) wherein the electrode tabs 112 are bent such that an outer section are bent in a second direction. id="p-77" id="p-77" id="p-77"

[0077]The first and second steps (steps 410 and 420) may be performed one after another (in either order) or simultaneously or contemporaneously, depending on the implementation. 16 id="p-78" id="p-78" id="p-78"

[0078] By performing the process 400, electrode tabs 112 can be shaped in such a way as to comprise a substantially serpentine or 'spine' shape between the edge of the electrode assembly 110 and a current collector 114, to which the ends of the electrode tabs 112 are attached. id="p-79" id="p-79" id="p-79"

[0079]Figures 5A to 5C schematically show three example techniques for performing the process for shaping electrode tabs 112 according to aspects of the present disclosure. ln all of the i||ustrated examples, an apparatus 200 for shaping the electrode tabs 112 comprises a shaping tool 230 having a first surface 202, a hammer 210 having a third surface 206, and a holder 240 for receiving the electrode stack 110. ln figures 5A to 5C, the electrode tabs 112 are shown schematically and not shaped. id="p-80" id="p-80" id="p-80"

[0080]According to the example shown in figure 5A, the holder 240 is moved down to bring the electrode tabs 112 into contact with the surface 202 of the shaping tool 230, and the hammer 210 (which may also be referred to as a 'horn') is brought against the surface 204 of the anvil 220, wherein said surface 204 is arranged below (in the stacking direction of the electrode stack 110) the surface 202 of the shaping tool 230. id="p-81" id="p-81" id="p-81"

[0081]ln an alternative arrangement of figure 5A, the shaping tool 230 may be an integral part of the anvil 220, such as formed as a protruding ledge that is attached to and, e.g., protrudes from a main body of the anvil 220. id="p-82" id="p-82" id="p-82"

[0082]According to the example shown in figure 5B, the holder 240 is static and the shaping tool 230 is moved, separately to the anvil 220, upwards against the electrode tabs 112 to form the first bend. The anvil 220 is moved up (in the first direction) against the hammer 210, maintaining the surface 204 of the anvil 220 below an extreme of the motion of the shaping tool 230 so as not to negate the first bend. The second bend is thus formed by the placement of the surface 206 of the hammer 210 below the extreme of the motion of the shaping tool 230. id="p-83" id="p-83" id="p-83"

[0083]According to the example shown in figure 5C, the hammer 210 is not brought against an anvil but is in effect a second shaping tool, along with the shaping tool 230, and the shaping tool 230 and the anvil 210 may be moved 17 at the same or similar time to thereby form the bends in the electrode tabs 112. After the shaping, the ends of the electrode tabs 112 may be laminated and/or pre-welded before being attached (e.g., welded) to a current collector. id="p-84" id="p-84" id="p-84"

[0084]|t will be appreciated that these three examples are merely intended to demonstrate some of the ways in which an apparatus 200 could be arranged and implemented to apply a shaping to the electrode tabs 112 that has at least two bends in opposite directions. ln further examples, additional shaping tools may be added to introduce further bends. id="p-85" id="p-85" id="p-85"

[0085]Moreover, the hammer 210 and anvil 220 may be configured to perform ultrasonic welding to thereby apply a pre-weld to the ends of the electrode tabs 112. For example, the surfaces 204 and/or 206 may be configured with a surface profiling to increase a contact surface area with the electrode tabs to perform an ultrasonic welding more effectively. id="p-86" id="p-86" id="p-86"

[0086]ln such an example, it will be appreciated that the bends provided in the electrode tabs 112 advantageously damp the vibrations taking place during ultrasonic welding and thus damage to the electrode tabs 112 and/or the electrode assembly 110 can be mitigated during an ultrasonic pre-welding of the electrode tabs 112. id="p-87" id="p-87" id="p-87"

[0087]Those skilled in the art will appreciate that the apparatus 200 may be adapted in any appropriate way, e.g., depending on the nature of the electrode assembly 110, requirements of earlier or later steps in cell assembly, etc. id="p-88" id="p-88" id="p-88"

[0088]lt will be further appreciated that the second bend should be applied in such a manner as not to (entirely) negate the first bend, else only one bend will remain as a result of the process and the benefits of the present approach may not be fully realized. id="p-89" id="p-89" id="p-89"

[0089]While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments are shown and described above by way of example in relation to the drawings, with a view to clearly explaining the various advantageous aspects of the present disclosure. lt should be understood, however, that the detailed description herein and the drawings 18 attached hereto are not intended to limit the disclosure to the particular form disclosed. Rather, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the following claims.

Claims

CLaims

1. A process (400) for shaping electrode tabs (112) extending from an edge of an electrode assembly (110), comprising: bending (410), in a first direction, an inner section (1 12b) of the electrode tabs (112) proximal to the edge of the electrode assembly (110); and bending (420), in a second direction opposite the first direction, an outer section (112c) of the electrode tabs (112), the outer section (112c) being further from the edge of the electrode assembly (110) than the inner section (112b).

2. The process according to claim 1, wherein bending in the second direction comprises laminating and/or welding the outer section of the electrode tabs together.

3. The process according to claim 1 or claim 2, wherein the bending in the first direction and the bending in the second direction are simultaneous or contemporaneous.

4. The process according to any preceding claim, wherein bending the inner section of the electrode tabs comprises: moving the electrode assembly in the second direction to bring the inner section of the electrode tabs into contact with a shaping surface; or moving a shaping surface in the first direction to bring the shaping surface into contact with the inner section of the electrode tabs.

5. A battery cell (100) comprising an electrode assembly (110), wherein electrode tabs (112) extending from an edge of the electrode assembly (110) are shaped according to the process (400) of any preceding claim.

6. A method for manufacturing the battery cell (100) according to claim 5, comprising: shaping electrode tabs (112) extending from each of opposite sides of an electrode assembly (110), according to the process (400) of any of claims 1 to 4; welding the electrode tabs (112) to respective current collectors (114) extending along said sides of the electrode assembly (110); and arranging the electrode assembly (110) and the current collectors (114) into an open end of a casing (102) for the battery cell (100), wherein said sides of the electrode assembly (110) are arranged perpendicular to the open end of the casing (102).

7. An apparatus (200) for performing the process (400) according to any of claims 1 to 4, comprising: a holder (240) for receiving the electrode assembly (110); 21 a first surface (202) configured to bend the inner section of the electrode tabs (112) in the first direction; and a second surface (206) configured to bend the outer section of the electrode tabs (112) in the second direction.

8. The apparatus according to claim 7, comprising: a shaping tool (230) comprising the first surface (202); and an anvi| (220) comprising the second surface (204).

9. The apparatus according to claim 8, wherein the shaping tool (230) is configured to move separately from the anvi| (220), or the shaping tool (230) is a protruding ledge protruding from the main body of the anvi| (220).

10. The apparatus according to any of claims 7 to 9, further comprising: a hammer comprising a third surface configured to be brought against the second surface of the anvi|.

11. The apparatus according to claim 10, wherein the second surface (204) and the third surface (206) are configured to apply a pre-weld to the electrode tabs.

12. A battery cell (100), comprising: an electrode assembly (110) having electrode tabs (112) extending from the edge thereof; and 22 a current collector (114); wherein a first section of the electrode tabs proximal the edge of the electrode assembly is bent in a first direction, and a second section of the electrode tabs, further from the edge of the electrode assembly than the first section, is bent in a second direction opposite the first direction.

13. The battery cell (100) according to claim 12, wherein the electrode assembly further comprises separator layers, and wherein a protruding section of a plurality of the separator layers is bent in the first direction to thereby provide an insulating wall between the current collector and the electrode assembly.

14. The battery cell (100) according to claim 12 or claim 13, wherein the electrode tabs (112) are attached to the current collector (114) on a first side thereof, and the shaped electrode tabs (112) extend past the first side with the first bend and are bent back on themselves with the second bend to be attached to the current collector.

15. The battery cell (100) according to any of claims 12 to 14, wherein the first bend and the second bend of the electrode tabs forms a substantially serpentine shape.