Secondary battery

Abstract

The present disclosure relates to a secondary battery. The technical problem of the present invention is to be solved by providing a secondary battery for preventing shorting from occurring due to the friction between electrode plates in an electrode assembly. To this end, the disclosure provides the secondary battery comprising: an electrode assembly which includes a first electrode, a second electrode and a separator positioned between the first electrode and the second electrode, and which is wound while forming a core part; and tape which is positioned on the side of the core part and which is provided at the front end of the first electrode.

Description

secondary batteries

[0001] The present disclosure relates to a secondary battery.

[0002] Secondary batteries, unlike non-rechargeable primary batteries, are rechargeable and dischargeable. Low-capacity secondary batteries are used in small, portable electronic devices such as smartphones, feature phones, laptop computers, digital cameras, and camcorders, while large-capacity secondary batteries are widely used as power sources for motor drives and power storage in hybrid and electric vehicles. These secondary batteries include electrodes, including a positive electrode and / or a negative electrode, an electrode assembly, a case housing the electrode assembly, and electrode terminals connected to the electrode assembly.

[0003] Secondary batteries can be classified into cylindrical batteries, pouch-type batteries, square batteries, coin-type batteries, etc. depending on the shape of the case or the shape of the assembled electrodes. In this case, the cylindrical battery includes an electrode assembly wound in a jelly roll shape.

[0004] Due to the structural characteristics of the jellyroll-shaped electrode assembly, there are thickness differences at the tab attachment point, the boundary between the active material layer and the substrate, the lamination tape attachment point, and the core. These differences contribute to stress accumulation due to expansion and contraction of the electrodes as lithium ions are inserted or removed during charging and discharging. This can lead to cracks in the electrodes.

[0005] Cracks in the electrodes can lead to reduced capacity and / or increased resistance, resulting in reduced output. Furthermore, cracks in the electrodes can lead to safety issues such as short circuits, low voltage, and fire. Therefore, measures must be taken to prevent cracks in the electrodes.

[0006] In particular, when the electrode is fused with the separator due to frictional resistance during repeated expansion and contraction, the stress at the step becomes greater.

[0007] The above-described information disclosed in the background technology of this invention is only intended to improve understanding of the background of the present invention, and therefore may include information that does not constitute prior art.

[0008] The present invention relates to a secondary battery that suppresses stress occurring at a step of an electrode assembly.

[0009] The present invention relates to a secondary battery that reduces frictional resistance occurring in steps of an electrode assembly.

[0010] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0011] According to one embodiment of the present invention for solving the above technical problem, a secondary battery comprises: a first electrode; a second electrode; and a separator positioned between the first electrode and the second electrode; a wound electrode assembly forming a core; and a tape positioned on the core side and provided at the tip of the first electrode.

[0012] According to the present invention, a secondary battery can be provided in which the problem of cracks occurring in electrodes is improved.

[0013] According to the present invention, a secondary battery with improved safety can be provided.

[0014] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0015] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0016] FIG. 1 is a cross-sectional view schematically showing a cylindrical secondary battery according to one embodiment of the present invention.

[0017] Figure 2 is a drawing schematically showing the core of a secondary battery.

[0018] Figure 3 is an enlarged view of A in Figure 2.

[0019] Figure 4 is a schematic drawing of a secondary battery according to one embodiment of the present invention.

[0020] FIG. 5 is a drawing schematically showing an example of a tape according to one embodiment of the present invention.

[0021] Figure 6 is a drawing schematically showing an example of tape attachment according to one embodiment of the present invention.

[0022] Figure 7 is a cross-sectional view showing an example of a tape according to one embodiment of the present invention.

[0023] Figure 8 is a drawing schematically showing an example of tape attachment according to one embodiment of the present invention.

[0024] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms or words used in this specification and claims should not be interpreted as limited to their typical or dictionary meanings, and should be interpreted with meanings and concepts that conform to the technical spirit of the present invention based on the principle that the inventor can appropriately define the concept of a term to best explain his or her own invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as substitutes for them at the time of filing this application.

[0025] Additionally, when used herein, the terms "comprise", "include" and / or "comprising", "including" specify the presence of stated features, numbers, steps, operations, elements, elements and / or groups thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, elements, elements and / or groups thereof.

[0026] Additionally, to facilitate understanding of the invention, the attached drawings may not be drawn to scale and some components may be exaggerated in size. Furthermore, identical components may be assigned the same reference numbers in different embodiments.

[0027] The statement that two compared objects are "identical" means "substantially identical." Therefore, "substantially identical" may include deviations considered low in the art, such as deviations of less than 5%. Furthermore, uniformity of a parameter over a given region may imply uniformity on average.

[0028] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0029] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0030] Any configuration being placed "on (or under)" or "above (or below)" a component may mean not only that any configuration is placed in contact with the upper surface (or lower surface) of said component, but also that other configurations may intervene between said component and any configuration placed on (or below) said component.

[0031] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component. Furthermore, when it is said that a part is electrically coupled to another part, this includes not only cases where they are directly connected, but also cases where they are connected with another element in between.

[0032] When reference is made throughout the specification to "A and / or B," this means A, B, or A and B, unless otherwise stated. In other words, "and / or" includes all or any combination of the listed items. When reference is made to "C through D," this means C or more and D or less, unless otherwise stated.

[0033] The terminology used herein is for the purpose of describing embodiments of the present disclosure and is not intended to be limiting of the present disclosure.

[0034]

[0035] FIG. 1 is a cross-sectional view schematically showing a cylindrical secondary battery according to one embodiment of the present invention.

[0036] As illustrated in FIG. 1, a cylindrical lithium ion secondary battery cell (100) according to an embodiment of the present invention may include a cylindrical case (50), an electrode assembly (40), and a cap assembly (90). In addition, the cylindrical lithium ion secondary battery cell (100) may, in some cases, further include a center pin (70). In addition, in the secondary battery cell (100) according to an embodiment of the present invention, the cap assembly (90) also performs a current interruption operation, and therefore, in some cases, it is also referred to as a current interrupt device.

[0037] The cylindrical case (50) may include a roughly circular bottom portion (51) and a cylindrical side wall (52) extending upwardly from the circumference of the bottom portion (51) by a certain length. The upper portion (101) of the cylindrical case (50) is open during the manufacturing process of the secondary battery. Therefore, during the assembly process of the secondary battery, the electrode assembly (40) and the center pin (70) may be inserted into the cylindrical case (50) together with an electrolyte. The cylindrical case (50) may be manufactured from, for example, but not limited to, steel, stainless steel, aluminum, an aluminum alloy, or an equivalent thereof.

[0038] In addition, the cylindrical case (50) may include a beading part (110) sunken inwardly at the lower portion centered around the cap assembly (90) to prevent the cap assembly (90) from being detached to the outside, and a crimping part (120) bent inwardly at the upper portion thereof.

[0039] The electrode assembly (40) may be accommodated inside a cylindrical case (50). The electrode assembly (40) may include a negative electrode plate (20) in which a negative electrode active material (e.g., graphite, carbon, etc.) is coated on a negative electrode collector plate, a positive electrode plate (10) in which a positive electrode active material (e.g., transition metal oxide (LiCoO2, LiNiO2, LiMn2O4, etc.)) is coated on a positive electrode collector plate, and a separator (30) positioned between the negative electrode plate (20) and the positive electrode plate (10) to prevent short circuit and allow only the movement of lithium ions. In addition, the negative electrode plate (20), the positive electrode plate (10), and the separator (30) may be wound in an approximately cylindrical shape. Here, for example and without limitation, the negative electrode collector plate may be made of copper (Cu) foil, the positive electrode collector plate may be made of aluminum (Al) foil, and the separator may be made of polyethylene (PE) or polypropylene (PP).

[0040] In addition, a negative electrode tab (not shown) that protrudes downwardly and is extended may be welded to the negative electrode plate (20), and a positive electrode tab (11) that protrudes upwardly and is extended may be welded to the positive electrode plate (10), but the opposite is also possible. In addition, for example, but not limited to, the negative electrode tab may be formed of copper (Cu) or nickel (Ni), and the positive electrode tab (11) may be formed of aluminum (Al).

[0041] Additionally, the negative tab of the electrode assembly (40) can be welded to the bottom (51) of the cylindrical case (50). Therefore, the cylindrical case (50) can operate as a negative electrode. Of course, conversely, the positive tab (11) can be welded to the bottom (51) of the cylindrical case (50), in which case the cylindrical case (50) can operate as a positive electrode.

[0042] In addition, a first insulating plate (not shown) coupled to a cylindrical case (50) and having a first lower hole (not shown) formed in the center and a second lower hole (not shown) formed on the outside thereof may be interposed between the electrode assembly (40) and the bottom portion (51). This first insulating plate serves to prevent the electrode assembly (40) from electrically contacting the bottom portion (51) of the cylindrical case (50). In particular, the first insulating plate serves to prevent the positive electrode plate (10) of the electrode assembly (40) from electrically contacting the bottom portion (51). Here, the first lower hole serves to allow the gas to quickly move upward through the center pin (70) when a large amount of gas is generated due to an abnormality in the secondary battery, and the second lower hole serves to allow the negative electrode tab to penetrate and be welded to the bottom portion (51).

[0043] In addition, a second insulating plate (80) coupled to the cylindrical case (50) and having a first upper hole (not shown) formed in the center and a plurality of second holes (not shown) formed on the outside thereof may be interposed between the electrode assembly (40) and the cap assembly (90). This second insulating plate (80) serves to prevent the electrode assembly (40) from electrically contacting the cap assembly (90). In particular, the second insulating plate (80) serves to prevent the negative plate (20) of the electrode assembly (40) from electrically contacting the cap assembly (90). Here, the first hole serves to allow the gas to quickly move to the cap assembly (90) when a large amount of gas is generated due to an abnormality in the secondary battery, and the second hole serves to allow the positive electrode tab to penetrate and be welded to the cap assembly (90). Additionally, the remaining second hole serves to allow the electrolyte to quickly flow into the electrode assembly (40) during the electrolyte injection process.

[0044] In addition, the diameter of the first hole of the first insulating plate and the second insulating plate (80) is formed smaller than the diameter of the center pin (70), thereby preventing the center pin (70) from electrically contacting the bottom (51) of the cylindrical case (50) or the cap assembly (90) due to external impact.

[0045] The center pin (70) is a hollow, circular pipe shape and can be connected to the approximate center of the electrode assembly (40). This center pin (70) can be manufactured from, for example, but not limited to, steel, stainless steel, aluminum, an aluminum alloy, or polybutylene terepthalate. This center pin (70) suppresses deformation of the electrode assembly (40) during charging and discharging of the secondary battery and serves as a passage for gases generated inside the secondary battery. Of course, in some cases, this center pin (70) may be omitted.

[0046] The cap assembly (90) includes a cap up. The cap assembly (90) may further include at least one of a cap down, a vent, and an insulator. The cap assembly (90) is coupled to an opening of the case (50) to seal the electrode assembly (40) within the case (50).

[0047] However, the present invention is not limited thereto, and the case may be configured in various shapes, such as circular or pouch-shaped. In addition, the case may be configured of a metal such as aluminum, aluminum alloy, nickel-plated steel, or a laminate film or plastic forming a pouch.

[0048]

[0049] Meanwhile, as described above, the electrode assembly (40) includes a negative electrode formed of a negative electrode plate (20), a positive electrode formed of a positive electrode plate (10), and a separator (30) positioned between the negative electrode and the positive electrode. In addition, the electrode assembly (40) is housed in a cylindrical case (50) together with an electrolyte (not shown). Hereinafter, the electrode assembly (40) and the electrolyte will be described.

[0050] A compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound) can be used as a cathode active material. Specifically, one or more of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0051] The above composite oxide may be a lithium transition metal composite oxide, and specific examples thereof include lithium nickel-based oxide, lithium cobalt-based oxide, lithium manganese-based oxide, lithium iron phosphate-based compound, cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0052] As an example, a compound represented by any one of the following chemical formulas may be used: Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); Li a FePO4(0.90≤a≤1.8).

[0053] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; L 1 is Mn, Al or a combination thereof.

[0054] A positive electrode for a lithium secondary battery may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer includes a positive electrode active material and may further include a binder and / or a conductive material.

[0055] The content of the positive electrode active material may be 90 wt% to 99.5 wt% with respect to 100 wt% of the positive electrode active material layer, and the contents of the binder and conductive material may be 0.5 wt% to 5 wt%, respectively, with respect to 100 wt% of the positive electrode active material layer.

[0056] Al may be used as the above current collector, but is not limited thereto.

[0057] The negative active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0058] The material capable of reversibly intercalating / deintercalating the lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0059] As the material capable of doping and dedoping the lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used. The Si-based negative electrode active material can be silicon, a silicon-carbon composite, SiOx (0 < x < 2), a Si-based alloy, or a combination thereof.

[0060] The above silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles.

[0061] The silicon-carbon composite may further comprise crystalline carbon. For example, the silicon-carbon composite may comprise a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer positioned on the surface of the core.

[0062] A negative electrode for a lithium secondary battery cell (100) includes a current collector and a negative electrode active material layer positioned on the current collector. The negative electrode active material layer includes a negative electrode active material and may further include a binder and / or a conductive material.

[0063] For example, the negative electrode active material layer may include 90 to 99 wt% of the negative electrode active material, 0.5 to 5 wt% of the binder, and 0 to 5 wt% of the conductive material.

[0064] The above binder may be a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof. When an aqueous binder is used as the negative electrode binder, a cellulose-based compound capable of imparting viscosity may be further included.

[0065] The negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a combination thereof.

[0066] The electrolyte for a lithium secondary battery cell (100) includes a non-aqueous organic solvent and a lithium salt.

[0067] The above non-aqueous organic solvent acts as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0068] The above non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, an aprotic solvent, or a combination thereof, and may be used alone or in combination of two or more thereof.

[0069] Additionally, when using a carbonate solvent, a mixture of cyclic carbonate and chain carbonate can be used.

[0070] Depending on the type of lithium secondary battery cell (100), a separator may be present between the positive and negative electrodes. Such a separator may be a multilayer film of polyethylene, polypropylene, polyvinylidene fluoride, or two or more layers thereof.

[0071] The above separator (30) may include a porous substrate and a coating layer including an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0072] The above organic material may include a polyvinylidene fluoride-based antibody or a (meth)acrylic polymer.

[0073] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include inorganic particles selected from, but not limited to, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0074] The organic and inorganic substances may be mixed and present in one coating layer, or a coating layer including an organic substance and a coating layer including an inorganic substance may be present in a laminated form.

[0075]

[0076] Figure 2 is a drawing schematically showing the core of a secondary battery.

[0077] In Fig. 1, a secondary battery (100) according to one embodiment of the present invention is described. In Fig. 2, an electrode assembly included in the secondary battery (100) is described in more detail.

[0078] In FIG. 2, 200 represents an electrode assembly (e.g., including 40 described in FIG. 1). In FIG. 2, 210 represents a first electrode, and 220 represents a second electrode.

[0079] The electrode assembly (200) includes a first electrode (210); a second electrode (220); and a separator (not shown, for example, including 30 described in FIG. 1) positioned between the first electrode (210) and the second electrode (220).

[0080] The electrode assembly (200) is formed in the form of a laminate in which, for example, a first electrode (210), a second electrode (220), and a separator are laminated. The electrode assembly (200) may have a jelly-roll shape formed as the laminate is wound.

[0081] The empty area corresponding to the center of the jelly roll is called the core (200c). That is, the electrode assembly (200) is formed by winding the laminate around the core (200c).

[0082] The second electrode (210) is positioned closer to the core (200c) than the first electrode (210). Specifically, the tip of the second electrode (210) is positioned closer to the core (200c) than the tip of the first electrode (210). That is, the second electrode (220) is wound first, and then the first electrode (210) is wound.

[0083] The first electrode (210) is, for example, an anode, and the second electrode (220) is, for example, a cathode. However, conversely, the first electrode (210) may be, for example, a cathode, and the second electrode (220) may be, for example, an anode.

[0084] As the second electrode (220) is positioned closer to the core (200c), the tip of the first electrode (210) is positioned on one surface of the second electrode (220). At this time, when the electrode assembly (200) is charged or discharged, the electrode assembly (200) expands or contracts. In this case, the tip of the first electrode (210) may cause friction on one surface of the second electrode (220). Accordingly, one surface of the second electrode (220) is bent or the tip of the first electrode (210) applies stress to one surface of the second electrode (220).

[0085] In Fig. 2, A represents a region where the second electrode (220) is bent due to stress. As shown in Fig. 2, the first electrode (210) applies increasingly greater stress to the second electrode (220) as it comes into contact with the bent portion of the second electrode (220). In this case, a short circuit may occur in the second electrode (220).

[0086] This is explained in more detail in Figure 3 below.

[0087]

[0088] Figure 3 is an enlarged view of A in Figure 2.

[0089] In FIG. 3, 210 represents a first electrode (e.g., including 10 described in FIG. 1, or including 210 described in FIG. 2). In FIG. 3, 220 represents a second electrode (e.g., including 10 described in FIG. 1, or including 210 described in FIG. 2).

[0090] The first electrode (210) includes a substrate (211) and a coating layer (212) formed on at least one surface of the substrate (211).

[0091] The coating layer (212) is formed on both sides of the substrate (211), for example, as illustrated in FIG. 3. However, the coating layer (212) may also be formed on one side of the substrate (211), for example, as opposed to the case illustrated in FIG. 3.

[0092] In addition, the coating layer (212) may be formed only on a portion of the surface of the substrate (211), for example. Accordingly, one or both sides of the substrate (211) include a region covered by the coating layer (212) and a region not formed with the coating layer (212) and thus exposed to the outside. At this time, for convenience, the region where the substrate (211) is exposed to the outside is referred to as a non-coated region (e.g., n described in FIGS. 5, 6, and 8). In addition, the region where the coating layer (212) is formed on the substrate (211) is referred to as a retaining region (e.g., a described in FIGS. 5, 6, and 8).

[0093] At this time, the coating layer (212) is formed in the form of a layer, for example, of a slurry containing the active material, conductive material, and binder described in FIG. 1. Alternatively, the coating layer (212) is, for example, a freestanding film containing the active material and conductive material. At this time, the description of the active material, conductive material, and binder is the same as or similar to that described in FIG. 1.

[0094] The first electrode (210) includes, for example, an anode.

[0095] The second electrode (220) includes a substrate (221) and a coating layer (222) formed on at least one surface of the substrate (221).

[0096] The coating layer (222) is formed on both sides of the substrate (221), for example, as illustrated in FIG. 3. However, the coating layer (222) may also be formed on one side of the substrate (211), for example, as opposed to the case illustrated in FIG. 3.

[0097] In addition, the coating layer (222) may be formed only on a portion of the surface of the substrate (221), for example. Accordingly, one or both sides of the substrate (221) include a region covered by the coating layer (222) and a region not formed with the coating layer (222) and thus exposed to the outside. At this time, for convenience, the region where the substrate (221) is exposed to the outside is referred to as a non-coated region (e.g., n described in FIGS. 5, 6, and 8). In addition, the region where the coating layer (222) is formed on the substrate (221) is referred to as a retaining region (e.g., a described in FIGS. 5, 6, and 8).

[0098] At this time, the coating layer (222) is formed in the form of a layer of a slurry containing, for example, an active material, a conductive material, and a binder as described in FIG. 1. Alternatively, the coating layer (222) is, for example, a freestanding film containing an active material and a conductive material. At this time, the description of the active material, the conductive material, and the binder is the same as or similar to that described in FIG. 1.

[0099] As described in FIG. 2, the second electrode (220) is positioned closer to the core (200c) of the electrode assembly (200). Accordingly, the tip (210e) of the first electrode is positioned on one side (220s) of the second electrode.

[0100] The tip (210e) of the first electrode may apply stress to the second electrode (220) by frictionally contacting one side (220s) of the second electrode. Alternatively, for example, the second electrode (220) may be stressed by a step generated by the first electrode (210) during repeated charging and discharging. The second electrode (220) may be bent as illustrated in FIG. 3.

[0101] In this case, in the area where the second electrode (220) is bent, the substrate (211) of the first electrode can apply force to the coating layer (222) of the second electrode as one surface (220s) of the second electrode. Accordingly, a short circuit may occur in the second electrode (220).

[0102] If a short circuit occurs in the electrode assembly (200), the secondary battery (100) may experience a decrease in charging / discharging efficiency or a decrease in capacity. Furthermore, the secondary battery (100) may cause safety issues.

[0103] Therefore, a solution is required that can solve the problem of the first electrode (210) and the second electrode (220) being stressed by friction or even causing a short circuit.

[0104]

[0105] Figure 4 is a schematic drawing of a secondary battery according to one embodiment of the present invention.

[0106] In Fig. 4, 210 represents a first electrode (e.g., including 210 described in Figs. 2 to 3). In Fig. 4, 220 represents a second electrode (e.g., including 210 described in Figs. 2 to 3).

[0107] A secondary battery (100) according to one embodiment of the present invention includes an electrode assembly (200) and a tape (300).

[0108] The electrode assembly (200) includes a first electrode (210); a second electrode (220); and a separator positioned between the first electrode (210) and the second electrode (220), and is wound while forming a core (200c).

[0109] The tape (300) is located on the side of the core (200c) and is provided at the tip (210e) of the first electrode (210).

[0110] For example, the tape (300) is formed on one side and / or the other side of the first electrode (210e) located on the tip end (210e) side of the first electrode. Accordingly, the first electrode (210) passes over one side (220s) of the second electrode (220) through the tape (300) attached to the tip end (210e) of the first electrode.

[0111] For example, the tape (300) may be attached to all or part of the area where the tip (210e) of the first electrode and one side (220s) of the second electrode can come into contact. For example, the tape (300) may be attached to one side of the first electrode (210) facing the second electrode (220). Alternatively, for example, the tape (300) may be attached to both sides of the first electrode (210).

[0112] For example, the tape (300) is attached to the tip end (210e) of the first electrode. Therefore, the tape (300) can be attached to one or both sides of the tip end (210e) of the first electrode.

[0113] The tape (300) can be attached to the tip (210e) of the first electrode to reduce the frictional force applied by the first electrode (210) to the second electrode (220).

[0114] At this time, the tape (300) includes, for example, a material having a low coefficient of friction. The low coefficient of friction includes, for example, a case where the coefficient of friction is 0.20 or less. Alternatively, the low coefficient of friction includes, for example, a case where the coefficient of friction is 0.19 or less. Alternatively, the low coefficient of friction includes, for example, a case where the coefficient of friction is 0.18 or less. Alternatively, the low coefficient of friction includes, for example, a case where the coefficient of friction is 0.17 or less. Alternatively, the low coefficient of friction includes, for example, a case where the coefficient of friction is 0.16 or less. Alternatively, the low coefficient of friction includes, for example, a case where the coefficient of friction is 0.15 or less. Alternatively, the low coefficient of friction includes, for example, a case where the coefficient of friction is 0.14 or less. Alternatively, the low coefficient of friction includes, for example, a case where the coefficient of friction is 0.13 or less. Alternatively, the low coefficient of friction includes, for example, a case where the coefficient of friction is 0.12 or less. Alternatively, a low coefficient of friction includes, for example, a coefficient of friction of 0.11 or less. Alternatively, a low coefficient of friction includes, for example, a coefficient of friction of 0.10 or less.

[0115] When the coefficient of friction exceeds 0.20, the first electrode (210) may stress the second electrode (220) due to the frictional force against the second electrode (220). However, the tape (300) may reduce the frictional force generated between the first electrode (210) and the second electrode (220) by including a material having a low coefficient of friction.

[0116] Through this, the secondary battery (100) according to one embodiment of the present invention can reduce the frictional force between electrodes and improve the problem of short circuits occurring in the electrode assembly (200). Furthermore, the secondary battery (100) can provide a secondary battery with improved safety.

[0117] Meanwhile, the width of the tape (300) may be the same as or similar to the width of the first electrode (210). For example, the width of the tape (300) is formed in a range of ±2 mm with respect to the width of the first electrode (210). Alternatively, the length of the tape (300) may be, for example, 2 to 10 mm. Through this, the tape (300) can reduce the frictional force of the first electrode (210) against the second electrode (220), while preventing the first electrode (210) and / or the second electrode (220) from being damaged by the tape (300).

[0118] Below, various examples of attaching such tape (300) to the first electrode (210) are described.

[0119]

[0120] FIG. 5 is a drawing schematically showing an example of a tape according to one embodiment of the present invention.

[0121] In Fig. 5, 210 represents a first electrode (e.g., including 210 described in Figs. 2 to 4). In Fig. 5, 300 represents a tape (e.g., including 300 described in Fig. 4).

[0122] A first electrode (210) according to one embodiment of the present invention includes a substrate (211) and a coating layer (212) provided on at least a portion of at least one surface of the substrate (211).

[0123] For example, according to one embodiment of the present invention, the tape (300) wraps around the side of the tip (210e) of the first electrode and is attached to at least a portion of one side and the other side of the tip (210e) of the first electrode. That is, the tape (300) may be formed in a U shape with respect to the tip (210e) of the first electrode.

[0124] Figure 5 (a) shows an example in which a tape (300) is provided on a coating layer (212).

[0125] As illustrated in (a) of FIG. 5, the coating layer (212) can be formed on the substrate (211) up to the tip end (210e) of the first electrode. In this case, for example, the tape (300) includes a first tape (301) provided on the tip end (210e) of the first electrode while covering a portion of the coating layer (212).

[0126] The first tape (301) is provided on the tip end (210e) of the first electrode and is attached to the upper surface, lower surface, and side surface of the tip end (210e) of the first electrode. At this time, the first tape (301) can be attached on the coating layer (212) of the first electrode.

[0127] Through this, the first tape (301) can be attached to the first electrode (210) even when the coating layer (212) is formed to the end of the substrate (211). In addition, the first tape (301) can be attached to both sides and the side surface of the tip (210e) of the first electrode, thereby minimizing the frictional force of the first electrode (210) against the second electrode (220).

[0128] Figure 5 (b) shows an example in which a tape (300) is provided on a substrate (211).

[0129] As illustrated in (b) of FIG. 5, the coating layer (212) may be formed on the substrate (211) but not on the tip end (210e) of the first electrode. In this case, the region where the coating layer (212) is formed on the substrate (211) is referred to as a holding region (a), and the region where the coating layer (212) is not formed on the substrate (211) and the substrate (211) is exposed is referred to as a non-coated region (n). In this case, for example, the tape (300) includes a second tape (302) provided on the tip end (210e) of the first electrode while covering a portion of the substrate (211).

[0130] The second tape (302) is provided on the tip end (210e) of the first electrode and is attached to the upper surface, lower surface, and side surface of the tip end (210e) of the first electrode. At this time, the second tape (302) can be attached to the base material (301) of the first electrode, and for example, can be attached to the uncoated portion (n) of the first electrode. However, unlike as shown in (b) of FIG. 5, the second tape (302) can also be attached to the uncoated portion (n) and a part of the holding portion (a). That is, when the second tape (302) is formed to be somewhat longer than the length of the uncoated portion (n), the second tape (302) can be further attached to the coating layer (212) as a part of the holding portion (a).

[0131] Through this, the second tape (302) can be attached even on a substrate (211) on which a coating layer (212) is not formed. In addition, the second tape (302) can be attached to both sides and the side surface of the tip (210e) of the first electrode, thereby minimizing the frictional force of the first electrode (210) against the second electrode (220).

[0132]

[0133] Figure 6 is a drawing schematically showing an example of tape attachment according to one embodiment of the present invention.

[0134] In Fig. 6, 210 represents a first electrode (e.g., including 210 described in Figs. 2 to 4). In Fig. 6, 300 represents a tape (e.g., including 300 described in Fig. 4).

[0135] A first electrode (210) according to one embodiment of the present invention includes a substrate (211) and a coating layer (212) provided on at least a portion of at least one surface of the substrate (211).

[0136] For example, the tape (300) according to one embodiment of the present invention is attached to one side and / or the other side of the tip portion (210e) of the first electrode. For example, the tape (300) includes a third tape (303) attached to one side of the tip portion (210e) of the first electrode. In this case, the tape (300) may be attached only on one side of the tip portion (210e) of the first electrode. Alternatively, for example, the tape (300) further includes a fourth tape (304) attached to the other side of the tip portion (210e) of the first electrode. In this case, the tape (300) may be formed in an 11 shape with respect to the tip portion (210e) of the first electrode.

[0137] Figure 6 (a) shows an example in which a tape (300) is provided on a coating layer (212).

[0138] As illustrated in (a) of Fig. 6, the coating layer (212) can be formed on the substrate (211) up to the tip end (210e) of the first electrode. In this case, for example, the third tape (303) and / or the fourth tape (304) are provided on the coating layer (212).

[0139] Through this, the third tape (303) and / or the fourth tape (304) can be attached to the first electrode (210) even when the coating layer (212) is formed to the end of the substrate (211). In addition, the third tape (303) and / or the fourth tape (304) can reduce friction while reducing material costs.

[0140] Fig. 6 (b) shows an example in which a tape (300) is provided on a substrate (211).

[0141] As illustrated in (b) of Fig. 6, the coating layer (212) may be formed on the substrate (211), but may not be formed on the tip portion (210e) of the first electrode. In this case, the region where the coating layer (212) is formed on the substrate (211) is referred to as a holding portion (a), and the region where the coating layer (212) is not formed on the substrate (211) and the substrate (211) is exposed is referred to as a non-coated portion (n). In this case, for example, the third tape (303) and / or the fourth tape (304) are provided on the substrate (211).

[0142] The third tape (303) and / or the fourth tape (304) are provided on the tip portion (210e) of the first electrode and are attached to the lower surface or the upper surface and the lower surface of the tip portion (210e) of the first electrode. At this time, the third tape (303) and / or the fourth tape (304) may be attached to the substrate (301) of the first electrode, and may be attached to, for example, the uncoated portion (n) of the first electrode. However, as illustrated in (b) of FIG. 5, the third tape (303) and / or the fourth tape (304) may also be attached to the uncoated portion (n) and a portion of the holding portion (a). That is, when the third tape (303) and / or the fourth tape (304) is formed to be somewhat longer than the length of the non-conductive portion (n), the third tape (303) and / or the fourth tape (304) may be further attached on the coating layer (212) as part of the retaining portion (a).

[0143] Through this, the third tape (303) and / or the fourth tape (304) can be attached even on a substrate (211) on which a coating layer (212) is not formed. In addition, the third tape (303) and / or the fourth tape (304) can be attached to both sides of the tip (210e) of the first electrode, thereby reducing the frictional force of the first electrode (210) against the second electrode (220).

[0144]

[0145] Figure 7 is a cross-sectional view showing an example of a tape according to one embodiment of the present invention.

[0146] In FIG. 7, 300 represents a tape (including, for example, 300 described in FIGS. 4 to 6).

[0147] A tape (300) according to one embodiment of the present invention includes a low-friction layer (310). The low-friction layer (310) includes, for example, a material having a low coefficient of friction. For example, the material having a low coefficient of friction is a material having a coefficient of friction of 0.20 or less. Alternatively, for example, the material having a low coefficient of friction is a material having a coefficient of friction of 0.19 or less. Alternatively, for example, the material having a low coefficient of friction is a material having a coefficient of friction of 0.18 or less. Alternatively, for example, the material having a low coefficient of friction is a material having a coefficient of friction of 0.17 or less. Alternatively, for example, the material having a low coefficient of friction is a material having a coefficient of friction of 0.16 or less. Alternatively, for example, the material having a low coefficient of friction is a material having a coefficient of friction of 0.15 or less. Alternatively, for example, the material having a low coefficient of friction is a material having a coefficient of friction of 0.14 or less. Alternatively, for example, the material having a low coefficient of friction is a material having a coefficient of friction of 0.13 or less. Alternatively, for example, a material having a low coefficient of friction is a material having a coefficient of friction of 0.12 or less. Alternatively, for example, a material having a low coefficient of friction is a material having a coefficient of friction of 0.11 or less. Alternatively, for example, a material having a low coefficient of friction is a material having a coefficient of friction of 0.10 or less.

[0148] When the coefficient of friction exceeds 0.20, even when the tape (300) is attached to the tip (210e) of the first electrode, the first electrode (210) and the second electrode (220) may be stressed by each other due to frictional force.

[0149] For example, the low-friction layer (310) is a material having a low coefficient of friction and includes at least one selected from the group consisting of E-CTFE, PEEK-mod, PTFE, silicone-based polymers, and combinations thereof.

[0150] The tape (300) can reduce stress occurring between the first electrode (210) and the second electrode (220) by including a low-friction layer (310). Furthermore, the tape (300) allows the tip (210e) of the first electrode to move along one side (220s) of the second electrode without applying force to the one side (220s) of the second electrode. Through this, the tape (300) can prevent a short circuit from occurring in the second electrode (220).

[0151] Meanwhile, the tape (300) according to one embodiment of the present invention may further include an adhesive layer (320). The adhesive layer (320) is formed on one surface of the low-friction layer (310). The adhesive layer (320) is provided between the low-friction layer (310) and the first electrode (210). The adhesive layer (320) enables the low-friction layer (310) to be adhered to the first electrode (210).

[0152] To this end, the adhesive layer (320) includes a material having adhesive properties. For example, the material having adhesive properties is at least one selected from the group consisting of acrylic adhesives, rubber adhesives, silicone adhesives, hot melt adhesives, and combinations thereof. Alternatively, for example, the material having adhesive properties includes at least one selected from the group consisting of polyurethane, epoxy resin, and polyolefin.

[0153] Through this configuration, the tape (300) according to one embodiment of the present invention can be attached to the tip (210e) of the first electrode to allow the first electrode (210) to slide on one surface (220s) of the second electrode.

[0154]

[0155] Figure 8 is a drawing schematically showing an example of tape attachment according to one embodiment of the present invention.

[0156] In FIG. 8, 210 represents a first electrode (e.g., 210 described in FIGS. 2 to 7).

[0157] In FIGS. 4 to 7, examples of the tape (300) being attached to the tip end (210e) of the first electrode have been described. However, the tape (300) may be further attached not only to the tip end (210e) of the first electrode, but also to one or both sides of the first electrode (210). In this way, the tape (300) may be provided in all or part of the area where a step occurs in the electrode assembly (200). Such examples are described in FIG. 8.

[0158] A first electrode (210) according to one embodiment of the present invention includes a holding portion (a) having a coating layer (212) formed on a substrate (211); and an electrode plate including a non-coated portion (n) on which a coating layer is not formed on the substrate (211); and a tab (213) bonded to the non-coated portion (n).

[0159] The tab (213) is formed such that one side thereof is bonded to the non-conductive portion (n). In addition, the other side of the tab (213) extends outward from the non-conductive portion (n). The tab (213) is connected to the outside, for example, through a lead tab (not shown), so that the electrode assembly (200) can be electrically connected to the outside. In other words, the tab (213) can serve as a passage through which the electrode assembly (200) can be charged and discharged.

[0160] For example, a tape (300) according to one embodiment of the present invention (e.g., including 300 described in FIGS. 4 to 7) may further include a fifth tape (305) provided on the non-woven portion (n) while covering at least a portion of the tab (213).

[0161] The fifth tape (305) covers at least a portion of one side of the tab (213). At this time, the fifth tape (305) may cover the entirety of one side of the tab (213), or may cover only a portion of one side of the tab (213). In addition, the fifth tape (305) may be attached to the uncoated portion (n) adjacent to the tab (213) while covering one side of the tab (213). Furthermore, the fifth tape (305) may also be attached to a portion of the retaining portion (a) adjacent to the uncoated portion (n).

[0162] Through this, the fifth tape (305) can prevent cracks from occurring on the substrate (211) due to the step between the tab (213) and the substrate (211). Furthermore, the fifth tape (305) can prevent cracks from occurring on the first electrode (210) due to the step between the substrate (211) and the coating layer (212).

[0163] Alternatively, for example, the tape (300) according to one embodiment of the present invention may further include a sixth tape (306) provided on at least a portion of the non-conductive portion (n) and the retaining portion (a).

[0164] The sixth tape (306) covers all or part of the uncoated portion (n) on which the tab (213) is not formed. For example, the sixth tape (306) may be attached to a surface of the substrate (211) on which the tab (213) is not formed. Furthermore, the sixth tape (306) may also be attached to a part of the retaining portion (a) adjacent to the uncoated portion (n).

[0165] Through this, the sixth tape (306) can prevent cracks from occurring on the first electrode (210) due to the step between the substrate (211) and the coating layer (212).

[0166] Furthermore, the fifth tape (305) and / or the sixth tape (306) can further prevent cracks from occurring on the first electrode (210) by reinforcing the strength of the relatively weak non-conductive portion (n).

[0167]

[0168] In this way, the tape (300) according to one embodiment of the present invention can reduce the occurrence of stress by dispersing the stress generated in the first electrode (210) or the second electrode (220) even when the electrode assembly (200) repeatedly contracts or expands due to charging and discharging. In addition, accordingly, the tape (300) can prevent cracks from occurring in the first electrode (210) or the second electrode (220).

[0169]

[0170] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0171]

[0172] 100: Secondary battery

[0173] 200: Electrode assembly

[0174] 210: First electrode

[0175] 220: Second electrode

[0176] 300: Tape

[0177]

[0178] A secondary battery according to one embodiment of the present invention has industrial applicability.

Claims

1. An electrode assembly comprising a first electrode; a second electrode; and a separator positioned between the first electrode and the second electrode; and forming a core and being wound; and A tape positioned on the side of the core and provided at the tip of the first electrode; Secondary battery.

2. In paragraph 1, A secondary battery, wherein the tip of the second electrode is located closer to the core than the tip of the first electrode.

3. In paragraph 1, A secondary battery, wherein the tape is attached to one side and the other side of the tip of the first electrode while wrapping around the side of the tip of the first electrode.

4. In paragraph 3, The first electrode comprises: a substrate; and a coating layer formed on at least one surface of the substrate; A secondary battery, wherein the tape includes a first tape provided at the tip of the first electrode while covering a portion of the coating layer.

5. In paragraph 3, The first electrode comprises: a substrate; and a coating layer formed on at least one surface of the substrate; A secondary battery, wherein the tape includes a second tape provided at the tip of the first electrode while covering a portion of the substrate.

6. In paragraph 1, A secondary battery, wherein the tape includes a third tape attached to one side of the tip of the first electrode and a fourth tape attached to the other side of the tip of the first electrode.

7. In paragraph 6, The first electrode comprises: a substrate; and a coating layer formed on at least one surface of the substrate; The third tape and the fourth tape are provided on the coating layer, a secondary battery.

8. In paragraph 6, The first electrode comprises: a substrate; and a coating layer formed on at least one surface of the substrate; A secondary battery wherein the third tape and the fourth tape are provided on a portion of the substrate on which the coating layer is not formed.

9. In paragraph 1, The above tape is a secondary battery including a low-friction layer having a friction coefficient of 0.2 or less.

10. In paragraph 9, A secondary battery, wherein the above low-friction layer is at least one selected from the group consisting of E-CTFE, PEEK-mod, PTFE, and silicone-based polymers.

11. In paragraph 10, A secondary battery, wherein the tape further includes an adhesive layer formed on one surface of the low-friction layer and adhering the low-friction layer to the first electrode.

12. In paragraph 1, The above first electrode is, A plate including a holding portion having a coating layer formed on a substrate; and a non-coating portion having no coating layer formed on the substrate; and a tab bonded to the above-mentioned non-conductive part; Secondary battery.

13. In paragraph 12, A secondary battery, wherein the tape further includes a fifth tape provided on the non-conductive portion while covering at least a portion of the tab.

14. In paragraph 12, A secondary battery, wherein the tape further includes a sixth tape provided on at least a portion of the non-conductive portion and the maintenance portion.

15. In paragraph 1, The above first electrode is a positive electrode, a secondary battery.

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