Electrode plate for secondary battery, battery cell comprising electrode plate for secondary battery, and method for manufacturing electrode plate for secondary battery

Abstract

Provided are an electrode plate for a secondary battery and a battery cell comprising same. The electrode plate for a secondary battery comprises: an electrode plate body which is made of a metal material and has at least one electrode tab disposed at the edge of one side; and a reinforcing member which is inserted into and coupled to the electrode plate body and has a plurality of voids, wherein at least some of the plurality of voids are filled with the metal material forming the electrode plate body.

Description

Secondary battery electrode plate, battery cell including secondary battery electrode plate, and method for manufacturing secondary battery electrode plate

[0001] The present invention relates to a secondary battery electrode plate, a battery cell including a secondary battery electrode plate, and a method for manufacturing a secondary battery electrode plate.

[0002] Unlike primary batteries, secondary batteries can be recharged and discharged, making them suitable for a wide range of applications, including digital cameras, mobile phones, laptops, hybrid vehicles, and electric vehicles. Secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-hydrogen batteries, with lithium-ion batteries becoming increasingly popular.

[0003] In the case of conventional lithium ion batteries, copper or aluminum foil, etc., is used as a metal current collector for the negative or positive electrode, and a negative or positive electrode active material is laminated on both sides to produce the negative or positive electrode.

[0004] In contrast, in the case of next-generation batteries such as lithium-sulfur batteries (Li-S batteries) or lithium metal batteries (Li-Metal batteries), the negative electrode may be composed of lithium metal itself. In this case, the lithium metal constituting the negative electrode plate has lower mechanical strength than the metal current collector of conventional negative electrodes, and thus there is a concern that it may be easily deformed or broken during the manufacturing process of the negative electrode. In particular, there was a problem that the electrode tab of the negative electrode made of lithium metal was pressed and spread out by pressure during the welding process with the lead tab, causing interference with other components of the battery cell or easily becoming stuck in the welding machine.

[0005] The present invention has been made to solve at least some of the problems of the prior art as described above, and provides a secondary battery electrode plate composed of lithium metal and having excellent mechanical strength, and a battery cell including the same.

[0006] In addition, an object of the present invention is to provide a secondary battery electrode plate capable of increasing the efficiency of a battery cell manufacturing process and a battery cell including the same.

[0007] In addition, an object of the present invention is to provide a secondary battery electrode plate and a battery cell including the same, which can significantly improve the weldability between the electrode tab and the lead tab and the tensile strength of the weld.

[0008] In order to achieve the above purpose, in embodiments of the present invention, a method for manufacturing a secondary battery electrode plate is provided, including a first fabric supply step in which a first fabric made of a metal material is supplied; a second fabric supply step in which a second fabric having a mesh structure with a plurality of pores is supplied; an alignment step in which the second fabric is aligned on one surface of the first fabric; and a pressing step in which the first fabric and the second fabric are pressed by a pressing member to insert the second fabric into the first fabric.

[0009] In embodiments, as the second fabric is inserted into the first fabric during the pressurizing step, the metal material forming the first fabric can fill at least some of the plurality of voids.

[0010] In embodiments, one side of the first fabric is divided into a first region and a second region along the width direction of the first fabric, and in the alignment step, the second fabric can be aligned on the first region so as not to overlap with the second region of the first fabric.

[0011] In embodiments, the method for manufacturing a secondary battery electrode plate further includes a tab forming step of forming an electrode tab by removing a scrap area formed on a first area of ​​a first raw material, and the tab forming step may be performed after the pressing step.

[0012] In the method for manufacturing a secondary battery electrode plate according to the embodiments, the metal material may be lithium or an alloy containing lithium.

[0013] In embodiments, a secondary battery electrode plate is provided, which comprises: a plate body portion made of a metal material, having one or more electrode tabs arranged on one edge; and a reinforcing member inserted into and joined to the plate body portion, wherein the metal material forming the plate body portion fills at least one of the plurality of voids.

[0014] In embodiments, the reinforcing member may include a tab reinforcement coupled to one or more electrode tabs.

[0015] In embodiments, one surface of the electrode body is divided into a first region formed along one edge on which one or more electrode tabs are arranged; and a second region formed along an edge opposite the one edge, and a reinforcing member can be inserted into and joined to the first region.

[0016] In embodiments, the metal material of the plate body portion can cover both one side of the reinforcing member and the other side opposite to the one side.

[0017] In embodiments, a portion of the reinforcing member may be exposed on one surface of the plate body.

[0018] In the secondary battery electrode according to the embodiments, the metal material may be lithium or an alloy containing lithium.

[0019] In embodiments, a battery cell is provided, comprising an electrode assembly including one or more positive electrode plates, one or more negative electrode plates, and one or more separators disposed between the one or more positive electrode plates and the one or more negative electrode plates; and a case in which the electrode assembly is accommodated, wherein the one or more negative electrode plates are formed of the secondary battery plates described above.

[0020] In embodiments, at least one of the one or more negative electrode plates may be formed by folding a single secondary battery electrode plate multiple times.

[0021] In embodiments, the battery cell may further include a lead tab that is ultrasonically welded to the electrode tab of one or more negative plates.

[0022] According to the secondary battery electrode plate of the embodiments and the battery cell including the same, an anode plate having excellent mechanical strength while being composed of lithium metal can be implemented.

[0023] In addition, according to the secondary battery electrode plate of the embodiments and the battery cell including the same, the efficiency of the manufacturing process of the battery cell can be increased.

[0024] In particular, according to the secondary battery electrode plate of the embodiments and the battery cell including the same, the weldability between the electrode tab and the lead tab and the tensile strength of the weld can be significantly improved.

[0025] Figure 1 is an exploded perspective view of a battery cell according to embodiments.

[0026] Fig. 2 is an exemplary cross-sectional view of an electrode assembly according to part II' of Fig. 1.

[0027] Figure 3 is an exploded perspective view of a secondary battery electrode plate according to an embodiment.

[0028] Figure 4 is an enlarged view of part A of Figure 3.

[0029] Fig. 5 is an exemplary cross-sectional view of a secondary battery electrode plate according to an embodiment.

[0030] Figure 6 is an exploded perspective view of a secondary battery electrode plate according to another embodiment.

[0031] Figure 7 is a reference drawing showing an electrode tab according to embodiments and an electrode tab according to a comparative example, each combined with a lead tab.

[0032] Figure 8 shows an exemplary configuration of a secondary battery electrode manufacturing device that produces secondary battery electrode plates according to embodiments.

[0033] Figure 9 shows how electrode tabs are formed in a secondary battery electrode plate according to embodiments.

[0034] Before going into the detailed description of the present invention, it should be noted that the terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted with meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term in order to explain his own invention in the best way. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical idea of ​​the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of this application.

[0035] The same reference numbers or symbols used in each drawing attached to this specification represent parts or components that perform substantially the same functions. For convenience of explanation and understanding, the same reference numbers or symbols may be used in different embodiments. In other words, even if components with the same reference numbers are depicted in multiple drawings, they do not necessarily represent a single embodiment.

[0036] In the following description, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as "comprises" or "comprises" should be understood to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0037] In addition, in the description below, expressions such as top, upper, lower, lower, side, front, and rear are expressed based on the direction shown in the drawing, and it is noted in advance that they may be expressed differently if the direction of the object in question changes.

[0038] Additionally, terms including ordinal numbers, such as "first," "second," etc., may be used in this specification and claims to distinguish between components. These ordinal numbers are used to distinguish identical or similar components from each other, and the use of these ordinal numbers should not be interpreted in a limited manner. For example, components associated with these ordinals should not be interpreted in a restricted manner, such as in the order of use or arrangement, based on their numbers. If necessary, each ordinal number may be used interchangeably.

[0039] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. However, the spirit of the present invention is not limited to the presented embodiments. For example, those skilled in the art who understand the spirit of the present invention may propose other embodiments within the spirit of the present invention by adding, modifying, or deleting components, etc., but such embodiments will also be considered to be within the spirit of the present invention. The shapes and sizes of elements in the drawings may be exaggerated for clarity.

[0040] Figure 1 is an exploded perspective view of a battery cell (1) according to embodiments.

[0041] Fig. 2 is an exemplary cross-sectional view of an electrode assembly (10) according to part II' of Fig. 1.

[0042] A battery cell (1) may include an electrode assembly (10) in which a plurality of electrode plates (11, 12) are stacked, a case (30) in which the electrode assembly (10) is accommodated, and a lead tab (20) electrically connected to the electrode assembly (10) and having a portion exposed to the outside of the case (30).

[0043] The case (30) may include an electrode receiving portion (33) in which an electrode assembly (10) is received, and a sealing portion (34) arranged along the edge of the electrode receiving portion (33). The electrode receiving portion (33) is formed by joining an upper case (30) and a lower case (30) vertically, and may have an internal space in which the electrode assembly (10) is received. The sealing portion (34) is formed by pressing or heat-welding the edges of the upper case (30) and the lower case (30) along the edge of the electrode receiving portion (33), and may block foreign substances or moisture from outside the case (30) from entering the electrode assembly (10) received inside the electrode receiving portion (33).

[0044] The case (30) may be a pouch-shaped case (30) made of a flexible material. For example, the case (30) may be made of an aluminum laminate sheet. However, the case of the battery cell (1) according to the embodiments may also be made of a can-shaped (or square) case or a cylindrical case made of a metal material such as aluminum, in addition to the above-described pouch-shaped case (30).

[0045] The electrode assembly (10) may have a structure in which one or more negative electrode plates (11) and one or more positive electrode plates (12) having opposite polarities are laminated with a separator (13) in between.

[0046] A separator (13) may be interposed between the negative electrode plate (11) and the positive electrode plate (12) to prevent electrical short circuits between the negative electrode plate (11) and the positive electrode plate (12) and to be configured to be impregnated with an electrolyte so that ions can pass through. The separator (13) may be formed of a porous polymer film or a porous non-woven fabric. However, in addition to the above materials, any material commonly used in lithium secondary batteries may be used as the material of the separator (13) without any special restrictions.

[0047] The negative electrode plate (11) and the positive electrode plate (12) may each be provided with electrode tabs (11a, 12a). The electrode tabs (11a, 12a) may be coupled with lead tabs (20) that serve as terminals in the battery cell (1), and thus the electrode assembly (10) and the lead tabs (20) may be electrically connected to each other. Various welding methods, including ultrasonic welding, or physical fastening methods, such as rivets, may be applied to the coupling between the electrode tabs (11a, 12a) and the lead tabs (20).

[0048] The lead tab (20) may be made of a conductive metal material. For example, the lead tab (20) may be made of nickel, copper, nickel-plated copper, aluminum, etc. An insulating member (21) may be placed between the lead tab (20) and the case (30). For example, the insulating member (21) may be made of a material having both insulating and adhesive properties, and may be bonded to the sealing portion (34) of the case (30) while wrapping a portion of the lead tab (20), thereby securing electrical insulation between the lead tab (20) and the case (30) and preventing the sealing performance between the lead tab (20) and the sealing portion (34) from being impaired.

[0049] The positive electrode plate (12) may have a structure in which a positive electrode active material layer is formed on a current collector. For example, the positive electrode plate (12) may be formed by applying a mixture of a positive electrode active material, a conductive material, and a binder to a current collector made of an aluminum alloy. In this case, any known material used in a lithium secondary battery may be used as the materials for the positive electrode active material, binder, conductive material, and current collector.

[0050] The negative electrode plate (11) of the battery cell (1) according to the embodiments may be made of a lithium metal sheet, unlike a conventional negative electrode plate.

[0051] A conventional negative electrode plate may have a structure in which a layer of negative electrode active material is formed on a current collector. For example, the negative electrode plate may be formed by applying a mixture of a negative electrode active material, a conductive agent, and a binder to a current collector made of a copper alloy material.

[0052] In contrast, the negative electrode plate (11) of the battery cell (1) according to the embodiments may have an integral electrode plate structure made of a lithium metal sheet. The lithium metal sheet is a flat sheet member made of lithium metal (i.e., lithium or an alloy material containing lithium), and the negative electrode plate (11) according to the embodiments and the negative electrode tab (11a) formed on one side of the negative electrode plate (11) can be implemented by appropriately processing the shape of the lithium metal sheet.

[0053] A battery cell (1) to which a negative electrode plate (11) made of a lithium metal sheet is applied can omit a conventional metal current collector made of nickel (Ni), aluminum (Al), copper (Cu), etc., so that not only is it advantageous in reducing the weight of the battery cell (1), but it can also have a very high energy density.

[0054] However, if the negative electrode plate (11) is made of only lithium metal without a metal current collector, the negative electrode plate (11) may be easily crumpled or broken during the manufacturing process due to the low mechanical strength of lithium, and there is a concern that the problem of lithium sticking to the manufacturing device may frequently occur, causing inefficiency in the manufacturing process.

[0055] In particular, when the electrode tab (11a) of the negative electrode plate (11) is made of lithium metal, there is a concern that the electrode tab (11a) may be pressed and spread out during the ultrasonic welding process for joining the electrode tab (11a) and the lead tab (20), causing a short circuit with other components of the battery cell (1) {e.g., the electrode tab (12a) of the positive electrode plate (12) or the case (30), etc.}, or that the lithium metal of the electrode tab (11a) may stick to the welding device.

[0056] To solve these problems, the negative electrode plate (11) according to the embodiments can be manufactured as a secondary battery plate as described through FIGS. 3 to 5. The negative electrode plate (11) thus manufactured has a structure in which a reinforcing member is combined, so that the mechanical strength, including tensile strength, can be significantly increased.

[0057] Hereinafter, with reference to FIGS. 3 to 5, a secondary battery electrode plate (100) used to manufacture an electrode assembly (10) of a battery cell (1) will be described in detail.

[0058] Figure 3 is an exploded perspective view of a secondary battery electrode plate (100) according to an embodiment.

[0059] Figure 4 is an enlarged view of part A of Figure 3.

[0060] Fig. 5 is an exemplary cross-sectional view of a secondary battery electrode plate (100) according to an embodiment.

[0061] The secondary battery electrode plate (100) according to the embodiment can be used to manufacture a negative electrode plate (11 in FIG. 2) or a positive electrode plate (12 in FIG. 2) of a battery cell (1 in FIG. 1). For example, the negative electrode plate (11) described in FIGS. 1 and 2 may be made of the secondary battery electrode plate (100) described in FIGS. 3 to 5.

[0062] The secondary battery electrode plate (100) illustrated in FIG. 3 may be a portion of a secondary battery electrode plate (100) that extends in one direction (e.g., in the X-axis direction) and is punched out.

[0063] The secondary battery electrode plate (100) according to the embodiments may include an electrode plate body part (110) made of a metal material and a reinforcing member (120) coupled to the electrode plate body part (110).

[0064] The electrode body (110) can form the outer shape of the electrode plate (100) for a secondary battery. An electrode tab (110a) can be arranged on one edge of the electrode plate body (110). For example, referring to FIG. 3, the electrode body (110) can have an integral structure in which an electrode tab (110a) protrudes from one side. When the negative electrode plate (11) of FIGS. 1 and 2 is manufactured as a secondary battery electrode plate (100), the electrode tab (110a) of the secondary battery electrode plate (100) can correspond to the electrode tab (11a) of the negative electrode plate (11).

[0065] The metal material forming the electrode body (110) may be lithium or an alloy containing lithium. When the electrode body (110) forming the outer shape of the electrode plate (100) for a secondary battery is formed of lithium or an alloy containing lithium, a negative electrode plate (11) can be implemented without a conventional metal current collector made of nickel (Ni), aluminum (Al), copper (Cu), etc., thereby greatly increasing the energy density of the battery cell (1).

[0066] However, if the secondary battery electrode plate (100) is made only of lithium metal, there is a risk that the electrode plate (100) for the secondary battery may be easily deformed or broken during the manufacturing process of the secondary battery electrode plate (100) due to the low strength of the lithium metal, which may cause process inefficiency during the roll-to-roll process.

[0067] To solve this, the secondary battery electrode plate (100) according to the embodiment may further include a reinforcing member (120) coupled to the electrode plate body (110).

[0068] The reinforcing member (120) can be inserted into and joined to the plate body (110). The reinforcing member (120) can be inserted into and joined to the inside of the plate body (110) by being pressed by external pressure while being seated on one surface of the plate body (110).

[0069] The reinforcing member (120) may be provided with a plurality of voids (122) that are open in the thickness direction of the reinforcing member (120) (e.g., the Z-axis direction of FIG. 3). At least some of the voids (122) may be filled by a metal material constituting the plate body (110) during the process of bonding the reinforcing member (120) to the plate body (110).

[0070] For example, when the plate body (110) is made of lithium or an alloy containing lithium having low hardness, when the reinforcing member (120) and the plate body (110) are pressed with a pressing member (e.g., PM of FIG. 8) while they are in contact with each other, the reinforcing member (120) can dig into the inside of the plate body (110) and be coupled to each other. In this process, the metal material (e.g., lithium or an alloy containing lithium) forming the plate body (110) can enter between the gaps (122) of the reinforcing member (120) and fill the gaps (122).

[0071] The reinforcing member (120) may be combined with the electrode plate body (110) to increase the mechanical strength of the electrode plate body (110). In particular, the reinforcing member (120) may include a tab reinforcing member (120a) combined with an electrode tab (110a) disposed on one side of the electrode plate body (110). The mechanical strength of the electrode tab (110a) may be increased by the tab reinforcing member (120), and accordingly, the ultrasonic welding process with the lead tab (20) may be performed more easily.

[0072] The reinforcing member (120) may have a mesh structure having a plurality of voids (122). For example, referring to FIG. 4, the mesh structure of the reinforcing member (120) may be formed by weaving thin and light fibers (121). A plurality of voids (122) may be formed between the fibers (121). However, the structure of the reinforcing member (120) is not limited to the woven mesh structure described above. The reinforcing member (120) may have any structure as long as it has a thickness that is thin enough to be inserted and coupled to the plate body (110) and has a plurality of voids (122) formed therein.

[0073] The fibers (121) constituting the reinforcing member (120) may be resin fibers made of polyethylene or polyamide, or metal fibers having a higher strength than lithium metal. However, the material of the fibers (121) constituting the reinforcing member (120) is not limited to those described above, and may be made of any material that has a strength sufficient to be inserted into the inside of the electrode body (110) by being pressed by the pressing member (PM).

[0074] FIG. 5 shows various cross-sectional structures of a secondary battery electrode plate (100) according to section II-II' of FIG. 3 in a state where the electrode plate body (110) and the reinforcing member (120) are combined in this manner.

[0075] Referring to (a) of FIG. 5, the reinforcing member (120) can be inserted into and joined to the inside of the plate body (110) through one surface of the plate body (110). In the process of joining the reinforcing member (120) and the plate body (110), the metal material of the plate body (110) penetrates between the gaps (122) of the reinforcing member (120) and fills the gaps (122), and the reinforcing member (120) can have a state in which a portion thereof is exposed on one surface of the plate body (110). Accordingly, since the area where the metal material of the plate body (110) is exposed on one surface of the plate body (110) is reduced, the occurrence of a sticking phenomenon at a portion where the manufacturing device for the secondary battery plate (100) and one surface of the plate body (110) are in direct contact can be suppressed.

[0076] In this case, the secondary battery electrode plate (100) may have a multilayer structure in which a first layer (L1) made of a metal material of the electrode plate body (110) and a second layer (L2) made of a metal material filling a reinforcing member (120) and a void (122) are arranged vertically.

[0077] Alternatively, the reinforcing member (120) may be combined in a state in which it is completely inserted into the plate body part (110), i.e., in a buried form. For example, referring to (b) of FIG. 5, the reinforcing member (120) may be combined with the plate body part (110) in a state in which the metal material of the plate body part (110) passes through the gap (122) of the reinforcing member (120) and wraps around the reinforcing member (120). Accordingly, the metal material of the plate body part (110) may cover both one side of the reinforcing member (120) and the other side opposite to the one side.

[0078] In this case, referring to (b) of FIG. 5, the secondary battery electrode plate (100) may have a multilayer structure in which a second layer (L2) made of a metal material filling a reinforcing member (120) and a void (122) is formed between a first layer (L1) made of a metal material of the electrode plate body (110) and a third layer (L3).

[0079] In this case, since the reinforcing member (120) is embedded into the interior of the electrode plate body (110), only the metal material of the electrode plate body (110) is exposed on the surface of the electrode plate (100) for a secondary battery, the change in the electrical properties of the surface of the electrode plate (100) for a secondary battery due to the reinforcing member (120) can be minimized.

[0080] The second layer (L2) illustrated in (a) or (b) of FIG. 5 can function as a reinforcing layer of the secondary battery electrode plate (100). That is, the second layer (L2) formed by laminating the electrode plate body (110) and the reinforcing member (120) in the secondary battery electrode plate (100) can prevent the secondary battery electrode plate (100) from being easily deformed or broken during the electrode assembly process, and can prevent the metal material forming the electrode plate body (110) from sticking to the electrode manufacturing device. Accordingly, the mechanical strength of the secondary battery electrode plate (100) can be dramatically increased compared to when it is made only of a soft metal material such as lithium metal, and the efficiency of the manufacturing process can be enhanced.

[0081] Alternatively, the reinforcing member (120) may be provided to have a thickness corresponding to the thickness of the plate body portion (110) (here, the thickness may mean the length in the Z-axis direction of FIG. 5). In this case, as the reinforcing member (120) is inserted and connected to the plate body portion (110), a mesh structure may be formed in which the reinforcing member (120) forms the basic skeleton of the plate (100) for a secondary battery and the metal material forming the plate body portion (110) is filled in the gap (122).

[0082] In this way, when manufacturing a negative electrode plate (11) using a secondary battery plate (100) to which a reinforcing member (120) is laminated, the mechanical strength including the tensile strength of the negative electrode plate (11) can be increased, thereby improving the manufacturing process of the electrode assembly (10). In particular, as shown in FIG. 2, when forming a negative electrode plate (11) by bending a single secondary battery plate (100) multiple times, manufacturing a negative electrode plate (11) using a secondary battery plate (100) to which a reinforcing member (120) is laminated can significantly reduce the risk of the negative electrode plate (11) being torn or cracked during the manufacturing process of the negative electrode plate (11).

[0083] Meanwhile, in another embodiment, the reinforcing member (120' of FIG. 6) may be coupled to only a portion of the electrode plate body (110). In particular, the electrode tab (110a) of the electrode plate for a secondary battery not only has a structure protruding from the edge of the electrode plate for a secondary battery, but also has a higher need for reinforcing strength than other portions of the electrode plate for a secondary battery because it is a portion coupled with the lead tab (20), and therefore, the reinforcing member may be configured to intensively reinforce the portion where the electrode tab (110a) is arranged. Hereinafter, a secondary battery electrode plate (100') according to another embodiment will be described with reference to FIG. 6.

[0084] Figure 6 is an exploded perspective view of a secondary battery electrode plate (100') according to another embodiment.

[0085] The secondary battery electrode plate (100') described in FIG. 6 is identical to the secondary battery electrode plate (100) described previously through FIGS. 3 to 5 in all other features except for the size of the reinforcing member (120') and the area where the reinforcing member (120') is joined in the electrode plate body (110), so any description overlapping with FIGS. 3 to 5 may be omitted.

[0086] Referring to FIG. 6, one side of the plate body (110) may be divided into a first region (P1) formed along one edge where the electrode tab (110a) is arranged, and a second region (P2) formed along the opposite edge of the one edge. That is, the first region (P1) of the plate body (110) may be a region including the electrode tab (110a) on one side of the plate body (110).

[0087] In an embodiment, the reinforcing member (120') may be coupled to the first region (P1) of the plate body (110). For example, during the manufacturing process of the plate (100') for a secondary battery, the reinforcing member (120') may be inserted into and coupled to the plate body (110) by being pressed by an external force while being aligned on the first region (P1) so as not to overlap with the second region (P2) of the plate body (110).

[0088] Accordingly, the mechanical strength of the electrode tab (110a) of the secondary battery electrode plate (100') can be effectively reinforced with a relatively small-sized reinforcing member (120').

[0089] The secondary battery electrode plate (100, 100') according to the embodiments includes an electrode tab (110a) reinforced by a reinforcing member (120, 120'), thereby increasing the stability of the bonding structure and the efficiency of the bonding process when bonded to the lead tab (20). Hereinafter, with reference to FIG. 7, the advantages of such a secondary battery electrode plate (100, 100') will be described in detail.

[0090] Fig. 7 is a reference drawing showing an electrode tab (110a) according to embodiments and an electrode tab (110a) according to a comparative example, respectively, combined with a lead tab (20).

[0091] Figure 7 (a) shows an electrode tab (NM) and a lead tab (20) according to a comparative example joined by ultrasonic welding, and Figure 7 (b) shows an electrode tab (110a) and a lead tab (20) according to an embodiment joined by ultrasonic welding.

[0092] The electrode tab (110a) according to the embodiment corresponds to any one of the electrode tabs (110a) of the secondary battery electrode plates (100, 100') described above in FIGS. 3 to 6, and may be formed by combining a reinforcing member (120, 120') with lithium or an alloy containing lithium. On the other hand, the electrode tab (NM) according to the comparative example may be formed of lithium or an alloy containing lithium, similar to the electrode tab (110a) according to the embodiment, but may not be formed by combining a reinforcing member (120, 120').

[0093] Meanwhile, the lead tab (20) described in FIG. 7 may correspond to the lead tab (20) described above through FIG. 1.

[0094] In the ultrasonic welding process, the base material (i.e., the electrode tab (110a) and the lead tab (20)) is positioned between a horn and an anvil, and then vibration friction is applied to bond the base materials together. During this process, continuous pressure is applied to the electrode tab (110a). Accordingly, if the electrode tab (110a) is made of a soft metal material such as lithium or a lithium alloy, there is a risk that it may be easily deformed by the pressure applied during the ultrasonic welding process.

[0095] In particular, in the case of an electrode tab (NM) made of only lithium or a lithium alloy, as shown in (a) of Fig. 7, it was observed that the weld portion (W1) of the electrode tab (NM) was unintentionally spread out or torn due to the pressure applied during the ultrasonic welding process. In particular, if the weld portion (W1) of the electrode tab (NM) is spread out wider than the original width of the electrode tab (NM), there is a concern that it may cause interference with other components of the battery cell (1).

[0096] On the other hand, as shown in (b) of Fig. 7, the electrode tab (110a) according to the embodiments has its mechanical strength reinforced by the reinforcing member (120), so that the phenomenon of spreading due to the pressure applied in the ultrasonic welding process is significantly reduced, and accordingly, the phenomenon of the welded portion (W2) being damaged is not observed. In particular, since the welded portion (W2) of the electrode tab (110a) is not easily deformed by the pressure of the ultrasonic welding, ultrasonic welding can be performed at a higher output, so that the welding strength between the electrode tab (110a) and the lead tab (20) can be dramatically increased.

[0097] Hereinafter, with reference to FIGS. 8 and 9, a method for manufacturing a secondary battery electrode plate according to embodiments will be described in detail.

[0098] Fig. 8 shows an exemplary configuration of a secondary battery electrode manufacturing device (2) that produces secondary battery electrode plates according to embodiments.

[0099] Figure 9 shows how electrode tabs are formed in a secondary battery electrode plate according to embodiments.

[0100] A secondary battery electrode plate manufacturing device (2) may include a first roll (FR) on which a first raw material (200) is wound, and a second roll (SR) on which a second raw material (300) is wound and coupled to the first raw material (200).

[0101] The first fabric (200) may be made of a metal material. Here, the first fabric (200) may be processed into the electrode plate body (110) described above in FIGS. 3 to 6 during the manufacturing process of the electrode plate for a secondary battery (100, 100' of FIGS. 3 to 6). Therefore, the description of the material of the first fabric (200) may refer to the description of the material of the electrode plate body (110) described above in FIGS. 3 to 6. That is, the first fabric (200), like the electrode plate body (110), may be made of lithium or an alloy containing lithium.

[0102] The second fabric (300) may have a mesh structure provided with a plurality of voids (122 in FIGS. 3 to 6). The second fabric (300) may be processed into a reinforcing member (120, 120') described in FIGS. 3 to 7 during the manufacturing process of the secondary battery electrode plate (100, 100'). Therefore, for a detailed description of the mesh structure of the second fabric (300), reference may be made to the description of the mesh structure of the reinforcing member (120, 120') described in FIGS. 3 to 7.

[0103] The first fabric (200) and the second fabric (300) can be unwinded from the first roll (FR) and the second roll (SR), respectively, and supplied to the pressurizing member (PM) in a mutually aligned state.

[0104] In the pressurizing process, the first fabric (200) and the second fabric (300) are joined to each other to form the first electrode structure (ES1). For example, referring to FIG. 8, in the pressurizing process, the first fabric (200) and the second fabric (300) are pressed by the pressurizing members (PM) while passing between the pressurizing members (PM) arranged vertically side by side, and thus the second fabric (300) can be inserted into and joined to the first fabric (200).

[0105] In the process of inserting the second fabric (300) into the first fabric (200), the metal material forming the first fabric (200) can fill the voids (122) of the second fabric (300). In particular, when the first fabric (200) is made of lithium or an alloy containing lithium having low hardness, through a process of applying pressure with a pressure member (PM) while the first fabric (200) and the second fabric (300) are in contact with each other, the lithium or the alloy containing lithium penetrates into and fills the plurality of voids (122) of the second fabric (300), whereby the first fabric (200) and the second fabric (300) are firmly bonded to each other.

[0106] Meanwhile, the second fabric (300) may be bonded to only a portion of the first fabric (200). For example, one side of the first fabric (200) may be divided into a first region (P1) and a second region (P2) along the width direction (Y-axis direction), and the second fabric (300) may be provided to have a narrower width than the first fabric (200) so as to be bonded only to the first region (P1) of the first fabric (200). In the manufacturing process of the secondary battery electrode plate (100') after the pressurizing process, the first region (P1) of the first fabric (200) to which the second fabric (300) is bonded may be processed to form an electrode tab (110a) of the secondary battery electrode plate (100'), and the specific shape and characteristics of the secondary battery electrode plate (100') manufactured thus may refer to the description of FIG. 6.

[0107] The first electrode structure (ES1) formed through the pressurization process can be input into the tab forming process.

[0108] Although Fig. 8 illustrates that the pressing process and the tab forming process are performed continuously, this is merely an example, and the pressing process and the tab forming process may be performed in separate process lines. For example, the first electrode structure (ES1) that has completed the pressing process may be wound on a separate rewinder roll (not shown), and this rewinder roll (not shown) may be transported to another location and then unwound to supply the first electrode structure (ES1) to the tab forming process.

[0109] In the tab forming process, a first electrode structure (ES1) is processed to produce a second electrode structure (ES2) provided with an electrode tab (200a).

[0110] In the tab forming process, the electrode tab (200a) can be formed by removing the scrap area (SA) formed on the first region (P1) of the first fabric (200). For example, referring to FIG. 9, the first electrode structure (ES1) in which the first fabric (200) and the second fabric (300) are combined is conveyed in one direction and passes through the tab forming member (TM), while the scrap area (SA) is removed to form the electrode tab (200a) {the arrow at the bottom of FIG. 9 indicates the conveying direction of the first electrode structure (ES1)}. A plurality of scrap areas (SA) are set in some edge regions of the first region (P1) of the first fabric (200) in which the second fabric (300) is combined, and by removing the scrap areas (SA), the electrode tab (200a) having a shape protruding from one edge of the first fabric (200) is formed. The electrode tab (200a) formed accordingly may correspond to the electrode tab (110a) described above through FIGS. 3 to 7.

[0111] Removal of the scrap area (SA) can be accomplished by a notching method using a cutting laser or an ultrasonic notching method using an ultrasonic cutting device. However, in addition to the above-described methods, any method capable of effectively cutting a portion of the first electrode structure (ES1) can be used for cutting the scrap area.

[0112] The second electrode structure (ES2) having the electrode tab (200a) formed thereon can be input into an electrode assembly assembly process. In the electrode assembly assembly process, the second electrode structure (ES2) and a plate (e.g., 12 in FIG. 2) having an opposite polarity are laminated to manufacture an electrode assembly (e.g., 10 in FIGS. 1 and 2).

[0113] The tab forming process and the electrode assembly assembly process may be performed sequentially. Alternatively, the second electrode structure (ES2) that has passed the tab forming process may be wound onto a separate rewinder roll (not shown) and then transported to another location for use in the electrode assembly assembly process.

[0114] The manufacturing method of the secondary battery electrode plate (100, 100') according to the secondary battery electrode plate manufacturing device (2) above is summarized as follows.

[0115] First, a first fabric supply step in which a first fabric (200) is supplied and a second fabric supply step in which a second fabric (300) is supplied are performed. The supplied second fabric (300) can be supplied to a pressure member (PM) in a state of being aligned on one side of the first fabric (200) in the alignment step. If necessary, the secondary battery electrode plate manufacturing device (2) may further include one or more guide rolls (not shown) to effectively perform the alignment step.

[0116] In the pressurizing step, a pressurizing process is performed in which the second fabric (300) is inserted into the first fabric (200) and joined by a pressurizing member (PM). Accordingly, the second fabric (300) is joined to the first fabric (200) with a plurality of voids (122) filled with the metal material of the first fabric (200).

[0117] The first fabric (200) and the second fabric (300) that are joined together in the pressurizing step are fed into the tab forming step. In the tab forming step, the scrap area (SA) formed on the first area (P1) of the first fabric (200) is removed to form an electrode tab (200a).

[0118] Through the above process, a secondary battery electrode plate (100, 100') can be manufactured in which a first fabric (200) made of a metal material and a second fabric (300) having a mesh structure are joined together.

[0119] The secondary battery electrode plate (100, 100') according to the embodiments can have a significantly increased mechanical rigidity by including a reinforcing member (120, 120') coupled to the electrode plate body (110) made of lithium or a lithium alloy, and thus the structural stability of the electrode assembly (10) can be increased.

[0120] In addition, since the secondary battery electrode plate (100, 100') to which the reinforcing member (120, 120') is combined has excellent mechanical strength, handling is easy in the manufacturing process of the battery cell (1), so that the manufacturing efficiency of the battery cell (1) can be increased. In particular, the secondary battery electrode plate (100, 100') to which the reinforcing member (120, 120') is combined can effectively prevent the occurrence of a sticking problem between the electrode tab (110a) made of lithium metal and the welding device during the ultrasonic welding process with the lead tab (20), and accordingly, not only the welding processability is increased, but also the maintenance of the welding device is easy, so that the manufacturing cost can be reduced.

[0121] In addition, since the mechanical strength of the secondary battery electrode plate (100, 100') is increased by the reinforcing member (120, 120'), the roll-to-roll process can be stably performed during the manufacturing process of the battery cell (1), and thus the manufacturing efficiency of the electrode assembly (10) and the battery cell (1) can be greatly increased.

[0122] While various embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be apparent to those skilled in the art that various modifications and variations are possible without departing from the technical spirit of the present invention as set forth in the claims. Furthermore, the embodiments described above may be implemented by deleting some components, and the embodiments may be implemented in combination with each other.

[0123] [Explanation of symbols]

[0124] 1... battery cell 10... electrode assembly

[0125] 11... negative plate 12... positive plate

[0126] 13... Separator 20... Lead tab

[0127] 21... Insulating member 30... Case

[0128] 100, 100'... Secondary battery electrode plate 110... Electrode body

[0129] 110a... Electrode tab 120, 120'... Reinforcing member

[0130] 120a... tab reinforcement 122... gap

[0131] 200... 1st fabric 300... 2nd fabric

[0132] FR... 1st roll SR... 2nd roll

[0133] PM... Pressing member TM... Tab forming member

[0134] ES1... first electrode structure ES2... second electrode structure

Claims

1. A first fabric supply step in which a first fabric made of a metal material is supplied; A second fabric supply step in which a second fabric having a mesh structure with multiple voids is supplied; An alignment step of aligning the second fabric on one side of the first fabric; and A method for manufacturing a secondary battery electrode plate, comprising a pressing step of pressing the first and second fabrics with a pressing member and inserting the second fabric into the first fabric.

2. In paragraph 1, A method for manufacturing a secondary battery electrode plate, wherein, in the pressurizing step, the metal material forming the first fabric fills at least a portion of the plurality of voids as the second fabric is inserted into the first fabric.

3. In paragraph 1, The above-mentioned one side of the above-mentioned first fabric is divided into a first region and a second region along the width direction of the above-mentioned first fabric, A method for manufacturing a secondary battery electrode plate, wherein, in the alignment step, the second fabric is aligned on the first area so as not to overlap with the second area of ​​the first fabric.

4. In paragraph 3, Further comprising a tab forming step of forming an electrode tab by removing a scrap area formed on the first area of ​​the first fabric, A method for manufacturing a secondary battery electrode plate, wherein the tab forming step is performed after the pressing step.

5. In paragraph 1, A method for manufacturing a secondary battery electrode plate, wherein the metal material is lithium or an alloy containing lithium.

6. A body of a plate made of a metal material, with one or more electrode tabs arranged on one edge; and It includes a reinforcing member having a plurality of voids and being inserted into and joined to the above-mentioned plate body part, A secondary battery electrode plate in which the metal material forming the above electrode body fills at least a portion of the plurality of voids.

7. In paragraph 6, A secondary battery electrode plate, wherein the reinforcing member includes a tab reinforcing portion coupled to one or more electrode tabs.

8. In paragraph 6, One side of the above-mentioned plate body a first region formed along the one edge on which the one or more electrode tabs are arranged; and It is divided into a second region formed along the opposite edge of the above one edge, The above reinforcing member is a secondary battery electrode plate inserted and joined into the first region.

9. In paragraph 6, A secondary battery electrode plate in which the metal material of the above electrode plate body covers both one side of the reinforcing member and the other side opposite to the one side.

10. In paragraph 6, A secondary battery electrode plate having a portion of the above reinforcing member exposed on one surface of the electrode plate body.

11. In paragraph 6, The above metal material is a secondary battery electrode plate which is lithium or an alloy containing lithium.

12. An electrode assembly comprising one or more positive electrode plates, one or more negative electrode plates, and one or more separators disposed between the one or more positive electrode plates and the one or more negative electrode plates; and A case in which the electrode assembly is accommodated is included, A battery cell comprising at least one negative electrode plate as a secondary battery electrode plate according to claim 6.

13. In paragraph 12, A battery cell in which at least one of the above one or more negative electrode plates is formed by bending one of the above secondary battery electrode plates multiple times.

14. In paragraph 12, A battery cell further comprising a lead tab joined by ultrasonic welding to the electrode tab of the one or more negative plates.

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