Electrodes for secondary batteries, electrode assemblies for secondary batteries including the same, and secondary batteries including the same

Abstract

According to exemplary embodiments of the present invention, an electrode for a secondary battery is provided. The electrode for the secondary battery includes an active material portion extending in a first direction and a second direction, and a tab portion adjacent to the active material portion in the second direction, wherein the tab portion may include a projection projecting in a direction intersecting the second direction.

Description

[Technical Field]

[0001] This application relates to electrodes for secondary batteries, electrodes for secondary batteries including the same, and secondary batteries including the same. This application claims the interests of Korean application No. 10-2024-0111511, filed on August 20, 2024, which is herein by reference in whole. [Background technology]

[0002] Unlike primary batteries, rechargeable batteries can be charged and discharged multiple times. Rechargeable batteries are widely used as an energy source for a variety of cordless devices such as handsets, laptops, and cordless vacuum cleaners. In recent years, improvements in energy density and economies of scale have dramatically reduced the manufacturing cost per unit capacity of rechargeable batteries, and as the driving range of battery electric vehicles (BEVs) increases to levels comparable to those of fuel-powered vehicles, the main applications of rechargeable batteries are shifting from mobile devices to mobility.

[0003] Secondary batteries are manufactured through electrode processes, assembly processes, and activation processes. The electrode process can provide an electrode assembly including a positive electrode, a negative electrode, and a separator membrane. The assembly process can enclose the electrode assembly and electrolyte in a case. In the activation process, the assembled battery cell can undergo charging, discharging, and aging steps. Through the activation process, the battery cell can be activated and stabilized by electrical energy. [Overview of the project] [Problems that the invention aims to solve]

[0004] The technical concept of this invention aims to solve the problem of providing electrodes for secondary batteries with improved performance and reliability.

[0005] The technical concept of this invention aims to solve the problem of providing an electrode assembly for a secondary battery with improved performance and reliability.

[0006] The technical concept of this invention aims to solve the problem of providing a secondary battery with improved performance and reliability.

[0007] The technical concept of this invention aims to solve the problem of providing an electrode for a secondary battery with improved safety.

[0008] The technical concept of this invention aims to solve the problem of providing an electrode assembly for a secondary battery with improved safety.

[0009] The technical concept of this invention aims to solve the problem of providing a secondary battery with improved safety. [Means for solving the problem]

[0010] According to an exemplary embodiment of the present invention for solving the above-mentioned problems, an electrode for a secondary battery is provided. The electrode for the secondary battery includes an active material portion extending in a first direction and a second direction, and a tab portion adjacent to the active material portion in the second direction, wherein the tab portion may include a projection protruding in a direction intersecting the second direction.

[0011] The tab portion may include a portion whose length in the first direction continuously decreases as it moves away from the active material portion along the second direction.

[0012] The tab portion further includes a body portion that is in contact with the active material portion, and the body portion may be trapezoidal in shape.

[0013] The tab portion further includes a body portion in contact with the active material portion, the body portion includes an upper edge extending in the first direction, a lower edge extending in the first direction and in contact with the active material portion, and a first side wall intersecting the first direction and connecting the upper edge and the lower edge, the first side wall may include the protruding portion.

[0014] The first side wall may further intersect with the second direction, and the protruding portion may protrude from the first side wall in a diagonal direction intersecting the first and second directions.

[0015] The length of the lower side of the body portion in the first direction may be the same as the length of the active material portion in the first direction, or may be smaller.

[0016] The body portion may further include a second side wall opposite to the first side wall, intersecting the first direction and connecting the upper side and the lower side, and the second side wall does not need to include the protruding portion.

[0017] The second side wall may extend in a diagonal direction intersecting the first direction and the second direction.

[0018] According to an exemplary embodiment of the present invention for solving the above-described problems, a secondary battery is provided. The secondary battery includes a first electrode including a first active material portion extending in a first direction and a second direction, and a first tab portion adjacent to the first active material portion in the second direction; a second electrode overlapping the first electrode in a third direction intersecting the first direction and the second direction; a case accommodating the first electrode and the second electrode; and a first lead connected to the first tab portion and including a portion exposed to the outside of the case, wherein the first tab portion may include a protruding portion protruding in a direction intersecting the second direction and the third direction.

[0019] The secondary battery may include a lead film between the first lead and the case, and a film layer between the protruding portion and the case, and the lead film and the film layer may contain the same substance.

[0020] The second electrode may include a second active material portion, and a second tab portion protruding in the same direction as the first tab portion of the first electrode, and the second tab portion may include a second protruding portion protruding in a direction intersecting the second direction and the third direction.

[0021] The first tab portion includes an upper edge extending in the first direction, a lower edge extending in the first direction and in contact with the active material portion, and a first side wall intersecting the first and second directions and connecting the upper edge and the lower edge, and the protruding portion may protrude from the first side wall.

[0022] The above-mentioned protrusions may protrude in diagonal directions intersecting the first direction and the second direction. [Effects of the Invention]

[0023] According to an exemplary embodiment of the present invention, the electrode for a secondary battery may include a tab portion whose width decreases as it moves away from the active material portion. This can reduce cell resistance.

[0024] According to exemplary embodiments of the present invention, the electrode for a secondary battery may include a tab portion with a protrusion. This allows for venting to be guided in one direction. Furthermore, the direction of venting can be predicted, improving the predictability of the venting direction.

[0025] According to exemplary embodiments of the present invention, electrodes for secondary batteries with improved performance and reliability can be provided.

[0026] According to exemplary embodiments of the present invention, it is possible to provide electrodes for secondary batteries with improved safety.

[0027] According to exemplary embodiments of the present invention, an electrode assembly for a secondary battery with improved performance and reliability can be provided.

[0028] According to exemplary embodiments of the present invention, an electrode assembly for a secondary battery with improved safety can be provided.

[0029] According to exemplary embodiments of the present invention, a secondary battery with improved performance and reliability can be provided.

[0030] According to exemplary embodiments of the present invention, a secondary battery with improved safety can be provided.

[0031] The effects obtained from exemplary embodiments of the present invention are not limited to those mentioned above, and other effects not mentioned can be clearly derived and understood by a person ordinary in the art to which the exemplary embodiments of this disclosure belong from the following description. That is, unintended effects associated with carrying out exemplary embodiments of this disclosure can also be derived by a person ordinary in the art to which the exemplary embodiments of this disclosure belong from the exemplary embodiments of this disclosure. [Brief explanation of the drawing]

[0032] [Figure 1] This figure schematically shows an electrode for a secondary battery according to an embodiment based on the technical concept of the present invention. [Figure 2] This is an enlarged view of a portion of an electrode for a secondary battery according to an embodiment based on the technical concept of the present invention. [Figure 3] This figure schematically shows an electrode for a secondary battery according to an embodiment based on the technical concept of the present invention. [Figure 4] This figure schematically shows an electrode for a secondary battery according to an embodiment based on the technical concept of the present invention. [Figure 5] This figure schematically shows an electrode for a secondary battery according to an embodiment based on the technical concept of the present invention. [Figure 6] This figure schematically shows an electrode for a secondary battery according to an embodiment based on the technical concept of the present invention. [Figure 7] This figure schematically shows an electrode assembly for a secondary battery according to an embodiment based on the technical concept of the present invention. [Figure 8] This figure schematically shows an electrode assembly for a secondary battery according to an embodiment based on the technical concept of the present invention. [Figure 9] This figure schematically shows a secondary battery according to an embodiment based on the technical concept of the present invention. [Figure 10] This is an enlarged view of a portion of a secondary battery according to an embodiment based on the technical concept of the present invention. [Modes for carrying out the invention]

[0033] Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. As a premise, terms and words used herein and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical idea of ​​the present invention, based on the principle that inventors may appropriately define the concepts of terms in order to best describe their own invention.

[0034] Therefore, the embodiments described herein and the configurations shown in the drawings represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the present invention; thus, there may be various equivalents and modifications that can substitute for them at the time of filing.

[0035] Furthermore, in describing the present invention, if it is determined that a specific description of a related known configuration or function may obscure the gist of the present invention, such detailed description will be omitted.

[0036] Since embodiments of the present invention are provided to give a more complete explanation to an ordinary person, the shapes and sizes of the components in the drawings may be exaggerated, omitted, or shown schematically for the sake of clarity. Accordingly, the sizes and proportions of each component do not fully reflect their actual sizes and proportions.

[0037] (First Embodiment) Figure 1 schematically shows an electrode 100 for a secondary battery according to an embodiment of the technical concept of the present invention.

[0038] Figure 2 is an enlarged view of a portion of an electrode for a secondary battery according to an embodiment of the technical concept of the present invention. Specifically, Figure 2 is an enlarged view of the EX1 region in Figure 1.

[0039] Referring to Figure 1, an electrode 100 for a secondary battery may include an active material portion 110 and a tab portion 120. The electrode 100 for a secondary battery illustrated in Figure 1 is a positive electrode, the active material portion 110 may be a positive electrode active material portion, and the tab portion 120 may be a positive electrode tab portion.

[0040] In the embodiment, the active material portion 110 may be formed by applying an active material onto a current collector. For example, the active material portion 110 may be formed by applying a positive electrode active material onto a positive electrode current collector.

[0041] The positive electrode active material is a substance capable of causing an electrochemical reaction. The positive electrode active material may be a lithium transition metal oxide. Examples of the positive electrode active material include layered compounds such as lithium cobalt oxide (LiCoO₂) and lithium nickel oxide (LiNiO₂) substituted with one or more transition metals, lithium manganese oxide substituted with one or more transition metals, and a lithium nickel-based oxide represented by the chemical formula LiNi 1-y M y O₂ (wherein M is any one selected from Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn and Ga, and 0.01≦y≦0.7), Li 1+z Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O₂, Li 1+z Ni 0.4 Mn 0.4 Co 0.2 O₂, such as Li 1+z Ni b Mn c Co 1-(b+c+d) M d O (2-e) A e (wherein -0.5≦z≦0.5, 0.1≦b≦0.8, 0.1≦c≦0.8, 0≦d≦0.2, 0≦e≦0.2, b+c+d<1, M is any one selected from Al, Mg, Cr, Ti, Si and Y, and A is any one selected from F, P and Cl), and a lithium nickel cobalt manganese composite oxide represented by the chemical formula Li 1+x M 1-y M’ y PO 4-z X zIt may contain one of the olivine-based lithium metal phosphates represented by the formula (wherein M is a transition metal (more specifically, one of Fe, Mn, Co, and Ni), M' is one of Al, Mg, and Ti, X is one of F, S, and N, -0.5 ≤ x ≤ +0.5, 0 ≤ y ≤ 0.5, 0 ≤ z ≤ 0.1).

[0042] The positive electrode current collector may have high conductivity without inducing chemical changes in the final manufactured secondary battery. The positive electrode current collector may include, for example, one of stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum. The positive electrode current collector may also include stainless steel surface-treated with carbon, nickel, titanium, and silver. The surface of the positive electrode current collector may include a micro-textured structure to enhance the adhesion of the active material. The shape of the positive electrode current collector may include one of film, sheet, foil, net, porous material, foam, and nonwoven fabric. The thickness of the positive electrode current collector may range from about 3 μm to about 500 μm.

[0043] In this embodiment, the active material portion 110 may further include a conductive material and a binder.

[0044] Conductive materials may be conductive without inducing chemical changes in the rechargeable battery that is ultimately manufactured. Conductive materials may include, for example, graphite such as natural graphite or artificial graphite, carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black, conductive fibers such as carbon fibers and metal fibers, metal powders such as carbon fluoride, aluminum, and nickel powder, conductive whiskers such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and polyphenylene derivatives.

[0045] A binder can improve the bonding between the active material and the conductive material, as well as the bonding force to the electrode plate. Binders may include, for example, polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-dientelpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, and various copolymers.

[0046] In this embodiment, the active material portion 110 may extend in a first direction D1 and a second direction D2. The active material portion 110 may have a short side extending in the first direction D1 and a long side extending in the second direction D2. The first direction D1 and the second direction D2 may intersect each other.

[0047] In the embodiment, the tab portion 120 may be adjacent to the active material portion 110 in the second direction D2. The tab portion 120 may refer to a portion of the secondary battery electrode 100 that is not coated with the active material as illustrated above. The tab portion 120 may include a body portion 121 and a projection portion 122. The body portion 121 may be adjacent to the active material portion 110 in the second direction D2. The projection portion 122 may protrude from the body portion 121. The body portion 121 and the projection portion 122 may together constitute the tab portion 120. For example, the body portion 121 and the projection portion 122 may be made of the same material and formed at the same time.

[0048] In the embodiment, the body portion 121 may be in contact with the active material portion 110 in a second direction D2. The body portion 121 may include a portion in which the length in the first direction D1 decreases as it moves away from the active material portion 110 in the second direction D2. The body portion 121 may include a portion in which the length in the first direction D1 decreases continuously as it moves away from the active material portion 110 along the second direction D2. Specifically, the body portion 121 may decrease in length as it moves away from the active material portion 110 along the second direction D2. For example, the body portion 121 may decrease continuously in length as it moves away from the active material portion 110 along the second direction D2.

[0049] For example, the body portion 121 may have a trapezoidal shape.

[0050] For example, the body portion 121 may include an upper edge 121_U, a lower edge 121_B, and two side walls 121_S1 and 121_S2 connecting them, which are parallel to each other. The upper edge 121_U may extend in a first direction D1. The lower edge 121_B may extend in a first direction D1. The upper edge 121_U and the lower edge 121_B may be spaced apart from each other and parallel along a second direction D2. The lower edge 121_B may be in contact with the active material portion 110. For example, the body portion 121 may share the lower edge 121_B with the active material portion 110 and be in contact with each other.

[0051] The two side walls 121_S1 and 121_S2 of the body portion 121 are not parallel to each other and may intersect with the first direction D1. For example, the two side walls 121_S1 and 121_S2 of the body portion 121 may intersect with the first direction D1 and the second direction D2, respectively. For example, the first side wall 121_S1 of the body portion 121 may extend in the second diagonal direction DD2. The second side wall 121_S2 of the body portion 121 may extend in the first diagonal direction DD1. The first diagonal direction DD1 and the second diagonal direction DD2 may intersect each other.

[0052] The first diagonal direction DD1 lies on the same plane as the first direction D1 and the second direction D2, and may intersect with them. The first diagonal direction DD1 may be one direction between the first direction D1 and the second direction D2. Similarly, the second diagonal direction DD2 lies on the same plane as the first direction D1 and the second direction D2, and may intersect with the first direction D1, the second direction D2, and the first diagonal direction DD1.

[0053] The lengths of the upper edge 121_U and the lower edge 121_B of the body portion 121 may differ from each other in the first direction D1. Specifically, the length of the upper edge 121_U in the first direction D1 may be smaller than the length of the lower edge 121_B in the first direction D1. That is, the length of the upper edge 121_U of the body portion 121 that does not contact the active material portion 110 in the first direction D1 may be smaller than the length of the lower edge 121_B that contacts the active material portion 110 in the first direction D1. As a result, the body portion 121 may have a trapezoidal shape in which the length in the first direction D1 decreases as it moves away from the active material portion 110 along the second direction D2, as described above.

[0054] The length of the lower edge 121_B of the body portion 121 in the first direction D1 may be the same as the length of the active material portion 110 in the first direction D1. The length of the upper edge 121_U of the body portion 121 in the first direction D1 may be smaller than the length of the active material portion 110 in the first direction D1.

[0055] In this embodiment, the first side wall 121_S1 of the body portion 121 may include a projection 122. Specifically, the projection 122 may project in a direction intersecting the first side wall 121_S1. On the other hand, the second side wall 121_S2 of the body portion 121 does not have to include a projection 122. For example, only one of the two side walls of the body portion 121 may include a projection 122.

[0056] In the embodiment, the projection 122 may be located on the first side wall 121_S1 of the body portion 121. The projection 122 may protrude from the first side wall 121_S1 of the body portion 121.

[0057] The protruding portion 122 may project in a direction intersecting the second direction D2. That is, the protruding portion 122 may project in a direction not parallel to the second direction D2. For example, the protruding portion 122 may project in a first diagonal direction DD1 that intersects the first direction D1 and the second direction D2.

[0058] In Figure 1, the projection 122 is exemplified as having a triangular shape projecting from the first side wall 121_S1 in the first diagonal direction DD1, but the shape of the projection 122 is not limited to this. For example, the projection 122 may have a rectangular, circular, elliptical, or irregular shape projecting from the first side wall 121_S1 in the first diagonal direction DD1.

[0059] The electrode 100 for a secondary battery according to an embodiment of the technical concept of the present invention includes a tab portion 120 in which the length in the first direction D1 decreases along the second direction D2, thereby reducing cell resistance. This can improve the performance and reliability of the electrode 100 for the secondary battery.

[0060] Specifically, as shown in Figure 2, the electron bottleneck phenomenon that can occur when electrons move from the active material portion 110 to the tab portion 120 of the secondary battery electrode 100 is improved, and the cell resistance can be reduced.

[0061] By including a projection 122 that protrudes in the first diagonal direction DD1 in the secondary battery electrode 100 according to the technical concept of the present invention, venting can be induced in one direction.

[0062] By including a protrusion 122 projecting in the first diagonal direction DD1 in the secondary battery electrode 100 according to the technical concept of the present invention, the direction of venting can be predicted. Furthermore, the predictability of the venting direction can be improved. As a result, the performance and reliability of the secondary battery electrode 100 can be improved, as well as safety.

[0063] Specifically, venting can be induced along the direction in which the protrusion 122 protrudes. For example, venting can be induced in the first diagonal direction DD1. For example, it can be predicted that venting will occur in the first diagonal direction DD1.

[0064] According to embodiments based on the technical concept of the present invention, an electrode 100 for a secondary battery with improved performance and reliability can be provided.

[0065] According to the embodiment based on the technical idea of the present invention, an electrode 100 for a secondary battery with improved safety can be provided.

[0066] (Second Embodiment) Figure 3 schematically illustrates an electrode 200 for a secondary battery according to an embodiment based on the technical idea of the present invention.

[0067] Referring to Figure 3, the electrode 200 for a secondary battery may include an active material portion 210 and a tab portion 220. The electrode 200 for a secondary battery illustrated in Figure 3 is a negative electrode, the active material portion 210 may be a negative electrode active material portion, and the tab portion 120 may be a negative electrode tab portion.

[0068] In the embodiment, the active material portion 210 may be formed by coating an active material on a current collector. For example, the active material portion 210 may be formed by coating a negative electrode active material on a negative electrode current collector.

[0069] The negative electrode active material may include, for example, carbon such as non-graphitizable carbon and graphite-based carbon. The negative electrode active material is, for example, Li x Fe₂O₃ (0≦x≦1), Li x WO₂ (0≦x≦1), Sn x Me 1-x Me’ y O z (wherein Me is any one of Mn, Fe, Pb and Ge, Me' is any one of Al, B, P, Si, Group 1 elements, Group 2 elements, Group 3 elements of the periodic table and halogen, 0<x≦1, 1≦y≦3, 1≦z≦8) and other metal composite oxides. The negative electrode active material may include, for example, any one of lithium metal, lithium alloys, silicon-based alloys, and tin-based alloys. The negative electrode active material may include, for example, metal oxides such as SnO, SnO₂, PbO, PbO₂, Pb₂O₃, Pb₃O₄, Sb₂O₃, Sb₂O₄, Sb₂O₅, GeO, GeO₂, Bi₂O₃, Bi₂O₄, and Bi₂O₅. The negative electrode active material may include, for example, a conductive polymer such as polyacetylene, a Li-Co-Ni-based material, and the like.

[0070] The negative electrode current collector may have high conductivity without inducing chemical changes in the final manufactured secondary battery. The negative electrode current collector may include one of the following: copper, stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum-cadmium alloy. The negative electrode current collector may also include stainless steel surface-treated with carbon, nickel, titanium, and silver, etc. The surface of the negative electrode current collector may include a micro-textured structure to enhance the adhesion of the active material. The shape of the negative electrode current collector may include one of the following: film, sheet, foil, net, porous material, foam, and nonwoven fabric. The thickness of the negative electrode current collector may range from approximately 3 μm to approximately 500 μm.

[0071] In this embodiment, the active material portion 210 may further include a conductive material and a binder. For details regarding the conductive material and binder of the active material portion 210, please refer to the description of the conductive material and binder of the active material portion 110 described with reference to Figure 1.

[0072] In this embodiment, the active material portion 210 may extend in a first direction D1 and a second direction D2. The active material portion 210 may have a short side extending in the first direction D1 and a long side extending in the second direction D2.

[0073] In the embodiment, the tab portion 220 may be adjacent to the active material portion 210 in the second direction D2. The tab portion 220 may include the active material portion 210, the body portion 221, and the protruding portion 222.

[0074] For details regarding the tab portion 220, body portion 221, and protrusion portion 222, refer to the description of the tab portion 120, body portion 121, and protrusion portion 222 of the secondary battery electrode 100 described with reference to Figure 1.

[0075] For example, the body portion 221 may be in contact with the active material portion 210 in a second direction D2. The body portion 221 may include a portion in which the length in the first direction D1 decreases as it moves away from the active material portion 210 along the second direction D2. For example, the length of the body portion 221 may decrease continuously as it moves away from the active material portion 210 along the second direction D2. For example, the body portion 221 may have a trapezoidal shape.

[0076] For example, the side wall of the body portion 221 includes a projection 222, and the projection 222 may project in a direction intersecting the side wall. Other side walls of the body portion 221 do not have to include the projection 222.

[0077] For example, the projection 222 may project in a direction intersecting the second direction D2. For example, the projection 222 may project in a first diagonal direction DD1 that intersects the first direction D1 and the second direction D2.

[0078] The electrode 200 for a secondary battery according to an embodiment of the technical concept of the present invention can reduce cell resistance by including a tab portion 220 in which the length in the first direction D1 decreases along the second direction D2.

[0079] By including a projection 222 that protrudes in the first diagonal direction DD1 in the secondary battery electrode 200 according to the technical concept of the present invention, venting can be induced in one direction. Furthermore, the direction of venting can be predicted, and the predictability of the venting direction can be improved.

[0080] According to embodiments based on the technical concept of the present invention, an electrode 200 for a secondary battery with improved performance and reliability can be provided.

[0081] According to embodiments based on the technical concept of the present invention, an electrode 200 for a secondary battery with improved safety can be provided.

[0082] (Third embodiment) Figure 4 schematically shows an electrode 100A for a secondary battery according to an embodiment based on the technical concept of the present invention. The following explanation will focus on the differences from the electrode 100 for a secondary battery described with reference to Figures 1 and 2.

[0083] Referring to Figure 4, the secondary battery electrode 100A may include an active material portion 110 and a tab portion 120A. The active material portion 110 of the secondary battery electrode 100A may be substantially identical to the active material portion 110 of the secondary battery electrode 100 described with reference to Figure 1.

[0084] In the embodiment, the tab portion 120A may be adjacent to the active material portion 110 in the second direction D2. The tab portion 120A may include a body portion 121A and a protruding portion 122A. The body portion 121A may be adjacent to the active material portion 110 in the second direction D2. The protruding portion 122A may protrude from the body portion 121A.

[0085] In the embodiment, the body portion 121A may be in contact with the active material portion 110 in the second direction D2. The body portion 121A may include a portion in which the length in the first direction D1 decreases as it moves away from the active material portion 110 along the second direction D2. The body portion 121A may include a portion in which the length in the first direction D1 decreases continuously as it moves away from the active material portion 110 along the second direction D2. Specifically, the body portion 121A may decrease in length as it moves away from the active material portion 110 along the second direction D2. For example, the body portion 121A may decrease continuously in length as it moves away from the active material portion 110 along the second direction D2.

[0086] For example, the body portion 121A may have a trapezoidal shape.

[0087] For example, the body portion 121A may include a parallel upper edge 121A_U, a lower edge 121A_B, and two side walls 121A_S1 and 121A_S2 connecting them. The upper edge 121A_U of the body portion 121A may extend in a first direction D1. The lower edge 121A_B of the body portion 121A may extend in a first direction D1. The upper edge 121A_U and the lower edge 121A_B of the body portion 121A may be separated from each other and parallel in a second direction D2. The lower edge 121A_B of the body portion 121A may be in contact with the active material portion 110.

[0088] The two side walls 121A_S1 and 121A_S2 of the body portion 121A are not parallel to each other and may intersect with the first direction D1. For example, the first side wall 121A_S1 of the body portion 121A may extend in the second diagonal direction DD2. The second side wall 121A_S2 of the body portion 121A may extend in the first diagonal direction DD1.

[0089] The lengths of the upper edge 121A_U and the lower edge 121A_B of the body portion 121A may differ from each other. Specifically, the length of the upper edge 121A_U of the body portion 121A may be shorter than the length of the lower edge 121A_B in the first direction D1. The length of the lower edge 121A_B of the body portion 121A may also be shorter than the length of the active material portion 110 in the first direction D1.

[0090] In this embodiment, the first side wall 121A_S1 of the body portion 121A may include a projection 122A. Specifically, the projection 122A may project in a direction intersecting the first side wall 121A_S1. On the other hand, the second side wall 121A_S2 of the body portion 121A does not have to include a projection 122A. For example, only one of the two side walls of the body portion 121A may include a projection 122A.

[0091] In this embodiment, the projection 122A may project in a direction intersecting the second direction D2. For example, the projection 122A may project in the first diagonal direction DD1.

[0092] (Fourth Embodiment) Figure 5 schematically shows an electrode 100B for a secondary battery according to an embodiment of the technical concept of the present invention. The following explanation will focus on the differences from the electrode 100 for a secondary battery described with reference to Figures 1 and 2.

[0093] Referring to Figure 5, the secondary battery electrode 100B may include an active material portion 110 and a tab portion 120B. The active material portion 110 of the secondary battery electrode 100B may be substantially identical to the active material portion 110 of the secondary battery electrode 100 described with reference to Figure 1.

[0094] In this embodiment, the tab portion 120B may be adjacent to the active material portion 110 in the second direction D2. The tab portion 120B may include a body portion 121B and a protruding portion 122B. The body portion 121B may be adjacent to the active material portion 110 in the second direction D2. The protruding portion 122B may protrude from the body portion 121B.

[0095] In the embodiment, the body portion 121B may be in contact with the active material portion 110 in the second direction D2. The body portion 121B may include a portion in which the length in the first direction D1 decreases as it moves away from the active material portion 110 along the second direction D2. The body portion 121B may include a portion in which the length in the first direction D1 decreases continuously as it moves away from the active material portion 110 along the second direction D2. Specifically, the body portion 121B may decrease in length as it moves away from the active material portion 110 along the second direction D2. For example, the body portion 121B may decrease continuously in length as it moves away from the active material portion 110 along the second direction D2.

[0096] For example, the body portion 121B may have a trapezoidal shape.

[0097] For example, the body portion 121B may include a mutually parallel upper edge 121B_U, a lower edge 121B_B, and two side walls 121B_S1 and 121B_S2 connecting them. The upper edge 121B_U of the body portion 121B may extend in a first direction D1. The lower edge 121B_B of the body portion 121B may extend in a first direction D1. The upper edge 121B_U and the lower edge 121B_B of the body portion 121B may be separated from each other and parallel in a second direction D2. The lower edge 121B_B of the body portion 121B may be in contact with the active material portion 110.

[0098] The two side walls 121B_S1 and 121B_S2 of the body portion 121B are not parallel to each other and may intersect with the first direction D1. For example, the first side wall 121B_S1 of the body portion 121B may extend in the second diagonal direction DD2. The second side wall 121B_S2 of the body portion 121B may extend in the second direction D2.

[0099] The lengths of the upper edge 121B_U and the lower edge 121B_B of the body portion 121B may differ from each other. Specifically, the length of the upper edge 121B_U of the body portion 121B may be smaller than the length of the lower edge 121B_B in the first direction D1. The length of the lower edge 121B_B of the body portion 121B may be smaller than the length of the active material portion 110 in the first direction D1.

[0100] In this embodiment, the first side wall 121B_S1 of the body portion 121B may include a projection 122B. Specifically, the projection 122B may project in a direction intersecting the first side wall 121B_S1. On the other hand, the second side wall 121B_S2 of the body portion 121B does not have to include a projection 122B. For example, only one of the two side walls of the body portion 121B may include a projection 122B.

[0101] In the embodiment, the projection 122B may be located on the first side wall 121B_S1 of the body portion 121B. The projection 122B may project from the first side wall 121B_S1 of the body portion 121B. The projection 122B may project in a direction intersecting the second direction D2. For example, the projection 122B may project in the first diagonal direction DD1.

[0102] In some other embodiments, unlike those shown, the first side wall 121B_S1 of the body portion 121B does not include the projection 122B, and the second side wall 121B_S2 of the body portion 121B may include the projection 122B. If the second side wall 121B_S2 of the body portion 121B includes the projection 122B, the projection 122B may project from the first side wall 121B_S1 in the first direction D1.

[0103] (Fifth embodiment) Figure 6 schematically shows an electrode 100C for a secondary battery according to an embodiment of the technical concept of the present invention. The following explanation will focus on the differences from the electrode 100 for a secondary battery described with reference to Figures 1 and 2.

[0104] Referring to Figure 6, the secondary battery electrode 100C may include an active material portion 110 and a tab portion 120C. The active material portion 110 of the secondary battery electrode 100C may be substantially identical to the active material portion 110 of the secondary battery electrode 100 described with reference to Figure 1.

[0105] In this embodiment, the tab portion 120C may be adjacent to the active material portion 110 in the second direction D2. The tab portion 120C may include a body portion 121C and a protruding portion 122C. The body portion 121C may be adjacent to the active material portion 110 in the second direction D2. The protruding portion 122C may protrude from the body portion 121C.

[0106] In this embodiment, the body portion 121C may be in contact with the active material portion 110 in the second direction D2. The body portion 121C may include a portion whose length in the first direction D1 is constant along the second direction D2.

[0107] For example, the body portion 121C may include a mutually parallel upper edge 121C_U, a lower edge 121C_C, and two side walls 121C_S1 and 121C_S2 connecting them. The upper edge 121C_U of the body portion 121C may extend in a first direction D1. The lower edge 121C_C of the body portion 121C may extend in a first direction D1. The lower edge 121C_C of the body portion 121C may be in contact with the active material portion 110. The two side walls 121C_S1 and 121C_S2 of the body portion 121C may extend in a second direction D2. The two side walls 121C_S1 and 121C_S2 of the body portion 121C may be parallel to each other. For example, the body portion 121C may be rectangular in shape.

[0108] In this embodiment, the first side wall 121C_S1 of the body portion 121C may include a projection 122C. Specifically, the projection 122C may project in a direction intersecting the first side wall 121C_S1. On the other hand, the second side wall 121C_S2 of the body portion 121C does not have to include a projection 122C. For example, only one of the two side walls of the body portion 121C may include a projection 122C.

[0109] In the embodiment, the projection 122C may be located on the first side wall 121C_S1 of the body portion 121C. The projection 122C may project from the first side wall 121C_S1 of the body portion 121C. The projection 122C may project in a direction intersecting the second direction D2. For example, the projection 122C may project in the first direction D1.

[0110] (Sixth Embodiment) Figure 7 schematically shows an electrode assembly 11 for a secondary battery according to an embodiment based on the technical concept of the present invention.

[0111] Referring to Figure 7, the secondary battery electrode assembly 11 may include a first electrode 300 and a second electrode 400 stacked in a third direction D3. The first electrode 300 may be similar to the secondary battery electrode 100 described with reference to Figures 1 and 2. For example, the first electrode 300 may be a positive electrode. The second electrode 400 may be similar to the secondary battery electrode 200 described with reference to Figure 3. For example, the second electrode 400 may be a negative electrode. A separation membrane (not shown) may be interposed between the first electrode 300 and the second electrode 400.

[0112] In this embodiment, the first electrode 300 may include a first active material portion 310 and a first tab portion 320. The first active material portion 310 of the first electrode 300 may be substantially identical to the active material portion 110 of the secondary battery electrode 100 described with reference to Figure 1.

[0113] The first tab portion 320 may be adjacent to the first active material portion 310 in the second direction D2. The first tab portion 320 may include a first body portion 321 and a first projection portion 322. The first body portion 321 may be adjacent to the first active material portion 310 in the second direction D2. The first projection portion 322 may project from the first body portion 321.

[0114] In the embodiment, the first body portion 321 may be in contact with the first active material portion 310 in a second direction D2. The first body portion 321 may include a portion whose length in the first direction D1 decreases as it moves away from the first active material portion 310 along the second direction D2. Specifically, the length of the first body portion 321 may decrease as it moves away from the first active material portion 310 along the second direction D2. For example, the first body portion 321 may have a trapezoidal shape.

[0115] In this embodiment, the first projection 322 may project in a direction intersecting the second direction D2. For example, the first projection 322 may project in a first diagonal direction DD1 that intersects the first direction D1 and the second direction D2.

[0116] In this embodiment, the second electrode 400 may include a second active material portion (not shown) and a second tab portion 420. The second active material portion of the second electrode 400 may be substantially identical to the active material portion 210 of the secondary battery electrode 200 described with reference to Figure 2. The second active material portion 410 may overlap the first active material portion 310 in the third direction D3.

[0117] The second tab portion 420 may be adjacent to the second active material portion in the second direction D2. The second tab portion 420 may include the second body portion 421 and the second projection portion 422. The second body portion 421 may be adjacent to the second active material portion 410 in the second direction D2. The second projection portion 422 may project from the second body portion 421.

[0118] In the embodiment, the second body portion 421 may be in contact with the second active material portion in the second direction D2. The second body portion 421 may include a portion whose length decreases in the second direction D1 as it moves away from the second active material portion along the second direction D2. Specifically, the length of the second body portion 421 may decrease in the second direction D1 as it moves away from the second active material portion along the second direction D2. For example, the second body portion 421 may have a trapezoidal shape.

[0119] In this embodiment, the second projection 422 may project in a direction intersecting the second direction D2. For example, the second projection 422 may project in a second diagonal direction DD1 that intersects the second direction D1 and the second direction D2.

[0120] In this embodiment, the first tab portion 320 of the first electrode 300 and the second tab portion 420 of the second electrode 400 may be arranged in the same direction with respect to the first active material portion 310 and the second active material portion. That is, the electrode assembly 11 for secondary batteries illustrated in Figure 7 may be an electrode assembly for a unidirectional cell.

[0121] When the electrode assembly 11 for a secondary battery according to an embodiment of the technical concept of the present invention is an electrode assembly for a unidirectional cell, each tab portion may include a protrusion. For example, the first tab portion 320 of the first electrode 300 may include a first protrusion 322, and the second tab portion 420 of the second electrode 400 may include a second protrusion 422. In this case, each of the above protrusions may protrude in the same direction. For example, the first protrusion 322 of the first tab portion 320 and the second protrusion 422 of the second tab portion 420 may protrude in the same direction.

[0122] According to embodiments of the technical concept of the present invention, an electrode assembly 11 for a secondary battery with improved performance and reliability can be provided.

[0123] According to embodiments based on the technical concept of the present invention, an electrode assembly 11 for a secondary battery with improved safety can be provided.

[0124] (Seventh Embodiment) Figure 8 schematically shows an electrode assembly 12 for a secondary battery according to an embodiment based on the technical concept of the present invention.

[0125] Referring to Figure 8, the secondary battery electrode assembly 12 may include a third electrode 500 and a fourth electrode 600 stacked in a third direction D3. The third electrode 500 may be similar to the secondary battery electrode 100 described with reference to Figures 1 and 2. For example, the third electrode 500 may be a positive electrode. The fourth electrode 600 may be similar to the secondary battery electrode 200 described with reference to Figure 3. For example, the fourth electrode 600 may be a negative electrode. A separation membrane (not shown) may be interposed between the third electrode 500 and the fourth electrode 600.

[0126] In this embodiment, the third electrode 500 may include a third active material portion 510 and a third tab portion 520. The third tab portion 520 may be adjacent to the third active material portion 510 in the second direction D2. The third tab portion 520 may include a third body portion 521 and a third projection portion 522. The third body portion 521 may be adjacent to the third active material portion 510 in the second direction D2. The third projection portion 522 may project from the third body portion 521.

[0127] In the embodiment, the third body portion 521 may be in contact with the third active material portion 510 in the second direction D2. The third body portion 521 may include a portion whose length in the first direction D1 decreases as it moves away from the third active material portion 510 along the second direction D2. Specifically, the length of the third body portion 521 may decrease as it moves away from the third active material portion 510 along the second direction D2. For example, the third body portion 521 may have a trapezoidal shape.

[0128] In this embodiment, the projection 522 may project in a direction intersecting the second direction D2. For example, the projection 522 may project in a third diagonal direction DD1 that intersects the first direction D1 and the second direction D2.

[0129] In this embodiment, the fourth electrode 600 may include a fourth active material portion (not shown) and a fourth tab portion 620. The fourth tab portion 620 may be adjacent to the fourth active material portion in the second direction D2. Unlike the third tab portion 520, which includes a protrusion 522, the fourth tab portion 620 does not have to include a protrusion.

[0130] In the embodiment, the fourth body portion 621 may be in contact with the fourth active material portion in the second direction D2. The fourth body portion 621 may include a portion whose length in the fourth direction D1 decreases as it moves away from the fourth active material portion along the second direction D2. Specifically, the length of the fourth body portion 621 may decrease as it moves away from the fourth active material portion along the second direction D2. For example, the fourth body portion 621 may have a trapezoidal shape.

[0131] In this embodiment, the third tab portion 520 of the third electrode 500 and the fourth tab portion 620 of the fourth electrode 600 may be arranged in opposite directions with respect to the third active material portion 510 and the fourth active material portion. That is, the secondary battery electrode assembly 12 illustrated in Figure 8 may be an electrode assembly for a bidirectional cell.

[0132] When the electrode assembly 12 for a secondary battery according to an embodiment of the technical concept of the present invention is an electrode assembly for a bidirectional cell, only the tab portion of one electrode may include a protrusion. For example, the third tab portion 520 of the third electrode 500 includes a protrusion 522, but the fourth tab portion 620 of the fourth electrode 600 does not have to include a protrusion.

[0133] According to embodiments based on the technical concept of the present invention, an electrode assembly 12 for a secondary battery with improved performance and reliability can be provided.

[0134] According to embodiments based on the technical concept of the present invention, an electrode assembly 12 for a secondary battery with improved safety can be provided.

[0135] (Eighth embodiment) Figure 9 schematically shows a secondary battery 10 according to an embodiment based on the technical concept of the present invention.

[0136] Figure 10 is an enlarged view of a portion of the secondary battery 10 according to an embodiment based on the technical concept of the present invention. Specifically, Figure 10 is an enlarged view of the EX2 region in Figure 9.

[0137] Referring to Figure 9, the secondary battery 10 may include an electrode assembly 10EA comprising a positive electrode, a negative electrode, and a separator membrane, and a case 10C that houses the electrode assembly 10EA. For example, the electrode assembly 10EA of the secondary battery 10 may include the secondary battery electrode assemblies 11 and 12 described with reference to Figures 7 and 8. Figure 9 illustrates the case in which the secondary battery electrode assembly 12 described with reference to Figure 8 is included.

[0138] In the embodiment, case 10C may include a metal layer and an outer resin layer. An adhesive and a corrosion-preventive layer may be further provided between the metal layer and the outer resin layer.

[0139] The metal layer may include any one of the following: an alloy of iron, carbon, chromium, and manganese; an alloy of iron, chromium, and nickel; and aluminum. The metal layer may be a gas barrier. The metal layer may block the entry and exit of gas through case 10C. The outer resin layer may be a surface protection layer. The outer resin layer may include a material having abrasion resistance and heat resistance, such as nylon resin.

[0140] The positive electrode may include a positive electrode active material portion (not shown) and a positive electrode tab portion 120. For details of the positive electrode active material portion and the positive electrode tab portion 120, refer to the description of the active material portion 110 and the tab portion 120 described with reference to Figures 1 and 2. For example, the positive electrode tab portion 120 may include a body portion 121 in contact with the positive electrode active material portion and a projection portion 122 protruding from the body portion 121. The projection portion 122 may protrude in directions intersecting the first direction D1 and the second direction D2. The projection portion 122 may protrude in a direction intersecting the third direction D3. For example, the projection portion 122 may protrude in the first diagonal direction DD1.

[0141] The above-mentioned negative electrode may include a negative electrode active material portion (not shown) and a negative electrode tab portion 220. For details of the negative electrode active material portion and the negative electrode tab portion 220, please refer to the description of the active material portion 210 and the tab portion 220 described with reference to Figure 3.

[0142] The positive electrode and the negative electrode can be stacked in the third direction D3.

[0143] In this embodiment, the secondary battery 10 may further include a positive lead 120P connected to a positive tab portion 120 and a negative lead 220N connected to a negative tab portion 220. The positive lead 120P and the negative lead 220N may be exposed to the outside of the case 10C.

[0144] In the embodiment, a lead film 120LF may be interposed between the positive electrode lead 120P and the case 10C. Similarly, a lead film 220LF may be interposed between the negative electrode lead 220N and the case 10C. The lead films 120LF and 220LF may be heat-adhesive and may be referred to as sealant layers. The lead films 120LF and 220LF enable sealing of the case 10C. For example, the lead films 120LF and 220LF can seal the case 10C, the positive electrode lead 120P, and the negative electrode lead 120N. The lead films 120LF and 220LF may include, for example, polyolefin resins such as polypropylene (PP) and polyethylene (PE).

[0145] In the embodiment, a film layer 122F may be interposed between the protrusion 122 and the case 10C. The film layer 122F may contain the same material as the lead films 120LF and 220LF. For example, the film layer 122F may contain a material that has heat-adhesion properties. For example, the film layer 122F may seal the protrusion 122 and the case 10C. For example, the film layer 122F may contain polyolefin resins such as polypropylene (PP) and polyethylene (PE).

[0146] In this embodiment, the film layer 122F contains a heat-adhesive resin, which can induce venting in one direction. This makes the venting direction predictable.

[0147] Specifically, referring to Figure 10, when heat H is generated from the active material portion of the electrode assembly 10EA, the heat H can be transferred to the positive electrode tab portion 120. The heat H can melt the film layer 122F of the protrusion 122. In particular, since the film layer 122F is positioned more adjacent to the active material portion than the lead film 120LF, the film layer 122F can melt before the lead film 120LF. When the film layer 122F melts, a gap can be created between the protrusion 122 and the case 10C, and venting can occur through this gap. That is, gas G can be discharged along the protrusion 122 in the first diagonal direction DD1. This makes it possible to induce venting in one direction and predict the direction of venting.

[0148] According to embodiments based on the technical concept of the present invention, a secondary battery 10 with improved performance and reliability can be provided.

[0149] According to embodiments based on the technical concept of the present invention, a secondary battery 10 with improved safety can be provided.

[0150] The present invention has been described in more detail above with reference to the drawings and embodiments. However, the configurations described in the drawings or embodiments described herein are merely one embodiment of the present invention and do not represent the entire technical concept of the present invention. Therefore, at the time of filing, there may be a variety of equivalents and modifications that can substitute for them.

Claims

1. Active material portion extending in the first direction and the second direction, In the second direction, the tab portion adjacent to the active material portion, Includes, The tab portion includes a projection that protrudes in a direction intersecting the second direction, and is an electrode for a secondary battery.

2. The electrode for a secondary battery according to claim 1, wherein the tab portion includes a portion whose length in the first direction continuously decreases as it moves away from the active material portion along the second direction.

3. The tab portion further includes a body portion that is in contact with the active material portion, The electrode for a secondary battery according to claim 1, wherein the body portion is trapezoidal.

4. The tab portion further includes a body portion that is in contact with the active material portion, The aforementioned body portion is The upper edge extending in the first direction, A lower edge extending in the first direction and in contact with the active material portion, It includes a first side wall that intersects the first direction and connects the upper edge and the lower edge, The electrode for a secondary battery according to claim 1, wherein the first side wall includes the protruding portion.

5. The first side wall further intersects with the second direction, The electrode for a secondary battery according to claim 4, wherein the protruding portion protrudes from the first side wall in a diagonal direction intersecting the first direction and the second direction.

6. The electrode for a secondary battery according to claim 4, wherein the length of the lower edge of the body portion in the first direction is the same as or smaller than the length of the active material portion in the first direction.

7. The body portion further includes a second side wall opposite to the first side wall, which intersects the first direction and connects the upper edge and the lower edge. The electrode for a secondary battery according to claim 4, wherein the second side wall does not include the protruding portion.

8. The electrode for a secondary battery according to claim 7, wherein the second side wall extends in a diagonal direction intersecting the first direction and the second direction.

9. A first electrode comprising a first active material portion extending in a first direction and a second direction, and a first tab portion adjacent to the first active material portion in the second direction, The first electrode and the second electrode overlap in a third direction intersecting the first and second directions, A case for housing the first electrode and the second electrode, A first lead connected to the first tab portion and including a portion exposed to the outside of the case, Includes, A secondary battery in which the first tab portion includes a projection that protrudes in a direction intersecting the second and third directions.

10. The lead film between the first lead and the case, The film layer between the protruding portion and the case, Includes, The secondary battery according to claim 9, wherein the lead film and the film layer contain the same substance.

11. The second electrode includes a second active material portion and a second tab portion that protrudes in the same direction as the first tab portion of the first electrode. The secondary battery according to claim 9, wherein the second tab portion includes a second projection that protrudes in a direction intersecting the second direction and the third direction.

12. The first tab portion is, The upper edge extending in the first direction, A lower edge extending in the first direction and in contact with the first active material portion, A first side wall intersects the first and second directions and connects the upper edge and the lower edge, Includes, The secondary battery according to claim 9, wherein the protruding portion protrudes from the first side wall.

13. The secondary battery according to claim 12, wherein the protruding portion protrudes in a diagonal direction intersecting the first direction and the second direction.

Images