Variable resistor structure, electrode assembly including same, battery cell, battery cell assembly, and battery pack

Abstract

According to exemplary embodiments, an electrode assembly is provided. The electrode assembly comprises: a positive electrode including a positive electrode current collector, a first positive electrode active material layer on the positive electrode current collector, and a second positive electrode active material layer spaced apart from the first positive electrode active material layer with the positive electrode current collector therebetween; a negative electrode including a negative electrode current collector, a first negative electrode active material layer on the negative electrode current collector, and a second negative electrode active material layer spaced apart from the first negative electrode active material layer with the negative electrode current collector therebetween; a separator between the positive electrode and the negative electrode; and a variable resistor structure in contact with the positive electrode and the negative electrode. The variable resistor structure includes a conductive foil and a variable resistor film on the conductive foil, and the variable resistor film includes a transition metal oxide.

Description

Variable resistance structure, electrode assembly including the same, battery cell, battery cell assembly and battery pack

[0001] The present invention relates to a variable resistance structure, an electrode assembly including the same, a battery cell, a battery cell assembly, and a battery pack. This application claims the benefit of Korean Application No. 10-2024-0087564, filed July 3, 2024, which is incorporated herein by reference in its entirety.

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. They are widely used as a power source for various wireless devices, including handsets, laptops, and cordless vacuum cleaners. Recently, improved energy density and economies of scale have dramatically reduced the per-unit manufacturing cost of secondary batteries. Furthermore, as the range of battery electric vehicles (BEVs) has increased to match that of fuel-powered vehicles, the primary use of secondary batteries is shifting from mobile devices to mobility.

[0003] The trend in technological development of secondary batteries for mobility is improving energy density and safety. The safety of secondary batteries for mobility is crucial, as it directly impacts the lives of passengers. A representative method for testing the safety of secondary batteries is the internal short-circuit test.

[0004] The technical idea of ​​the present invention aims to solve a problem by providing a variable resistance structure with improved reliability, an electrode assembly including the same, a battery cell, a battery cell assembly, and a battery pack.

[0005] According to exemplary embodiments of the present invention for solving the above-described problem, an electrode assembly is provided. The electrode assembly includes a positive electrode including a positive current collector, a first positive active material layer on the positive current collector, and a second positive active material layer spaced apart from the first positive active material layer with the positive current collector interposed therebetween; a negative electrode including a negative current collector, a first negative active material layer on the negative current collector, and a second negative active material layer spaced apart from the first negative active material layer with the negative current collector interposed therebetween; a separator between the positive electrode and the negative electrode; and a variable resistance structure in contact with the positive electrode and the negative electrode, wherein the variable resistance structure includes a conductive foil and a variable resistance film on the conductive foil, and the variable resistance film includes a transition metal oxide.

[0006] The above variable resistance film includes VO2.

[0007] The above variable resistance structure has a step shape.

[0008] The positive electrode current collector includes a positive electrode tab, and the variable resistance structure includes a first portion on the positive electrode tab and a second portion between the negative electrode and the separator.

[0009] The above conductive foil is in contact with the above positive tab.

[0010] The above conductive foil is bonded to the positive tab by an adhesive.

[0011] The conductive foil is spaced apart from the second negative active material layer with the variable resistance film interposed therebetween.

[0012] The above variable resistance film is in contact with the second negative electrode active material layer.

[0013] The above variable resistance structure further includes an insulating layer interposed between the variable resistance film and the cathode.

[0014] The above conductive foil is in contact with the second negative electrode active material layer.

[0015] The conductive foil is spaced apart from the positive tab with the variable resistance film interposed therebetween.

[0016] The above variable resistance film is in contact with the above positive electrode tab.

[0017] The negative electrode current collector includes a negative electrode tab, and the variable resistance structure includes a first portion on the negative electrode tab and a second portion between the negative electrode and the separator.

[0018] The variable resistance structure includes a first portion between the anode and the separator and a second portion between the cathode and the separator.

[0019] The positive electrode collector includes a positive tab, the negative electrode collector includes a negative tab, and the variable resistance structure is spaced apart from each of the positive electrode tab and the negative electrode tab.

[0020] The above variable resistance structure has a C shape.

[0021] According to exemplary embodiments, an electrode assembly is provided. The electrode assembly includes a positive electrode including a positive current collector, a first positive active material layer on the positive current collector, and a second positive active material layer spaced apart from the first positive active material layer with the positive current collector interposed therebetween; a negative electrode including a negative current collector, a first negative active material layer on the negative current collector, and a second negative active material layer spaced apart from the first negative active material layer with the negative current collector interposed therebetween; a separator between the positive and negative electrodes; and a variable resistance structure in contact with the positive and negative electrodes, the variable resistance structure including a conductive foil and a variable resistance film on the conductive foil, and a first resistivity of the variable resistance film at a first temperature being at least twice as large as a second resistivity at a second temperature higher than the first temperature.

[0022] The first temperature is less than 341K, and the second temperature is greater than 341K.

[0023] According to exemplary embodiments of the present invention, a variable resistance structure capable of simulating an internal short circuit, an electrode assembly including the variable resistance structure, a battery cell, a battery cell assembly, and a battery pack are provided. The variable resistance structure is manufactured based on a transition metal oxide such as VO2, and can provide highly reproducible and reliable internal short circuit test results.

[0024] The effects that can be obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects resulting from practicing the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0025] FIG. 1 is a flowchart illustrating a method for manufacturing a variable resistance structure according to exemplary embodiments.

[0026] FIG. 2 is a plan view illustrating a method for manufacturing a variable resistance structure according to exemplary embodiments.

[0027] Figure 3 is a side view of the workpiece of Figure 2.

[0028] FIG. 4 is a plan view illustrating a method of manufacturing a variable resistance structure according to exemplary embodiments.

[0029] FIG. 5 is a plan view of a variable resistance structure according to exemplary embodiments.

[0030] FIG. 6 is a side view of a variable resistance structure according to exemplary embodiments.

[0031] Figure 7 is a cross-sectional view taken along the cutting line 5A-5A' of Figure 5.

[0032] FIG. 8 is a flowchart illustrating a method for manufacturing an electrode assembly according to exemplary embodiments.

[0033] Figure 9 is a plan view of the anode.

[0034] Figure 10 is a side view of the bipolar electrode.

[0035] Figure 11 is a plan view showing the anode and separator.

[0036] Figure 12 is a side view showing the anode and separator.

[0037] Figure 13 is a plan view showing the anode, separator, and variable resistor structure.

[0038] Figure 14 is a side view showing the anode, separator, and variable resistor structure.

[0039] Figure 15 is a plan view of an electrode assembly according to exemplary embodiments.

[0040] FIG. 16 is a side view of an electrode assembly according to exemplary embodiments.

[0041] Figure 17 illustrates an electrode assembly according to other exemplary embodiments.

[0042] Figure 18 illustrates an electrode assembly according to other exemplary embodiments.

[0043] Figure 19 illustrates an electrode assembly according to other exemplary embodiments.

[0044] Figure 20 is a cross-sectional view taken along the cutting line 19A-19A' of Figure 19.

[0045] Fig. 21 is a cross-sectional view taken along the cutting line 19B-19B' of Fig. 19.

[0046] Fig. 22 is a cross-sectional view showing a variable resistance structure.

[0047] FIG. 23 is a drawing showing a battery cell according to exemplary embodiments.

[0048] Figure 24 is an exploded perspective view of a battery cell according to exemplary embodiments.

[0049] FIG. 25 is an exploded perspective view of a battery cell assembly according to exemplary embodiments.

[0050] Figure 26 is a cross-sectional view taken along the cutting line 25A-25A' of Figure 25.

[0051] FIG. 27 is a plan view of a battery pack according to exemplary embodiments.

[0052] FIG. 28 is a flowchart illustrating an internal short circuit test method according to exemplary embodiments.

[0053] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that aligns with the technical spirit of the present invention.

[0054] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0055] In addition, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description is omitted.

[0056] Since the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, the shapes and sizes of components in the drawings may be exaggerated, omitted, or schematically illustrated for clearer explanation. Accordingly, the sizes and proportions of each component do not fully reflect the actual sizes or proportions.

[0057]

[0058] (Embodiments 1 and 2)

[0059] FIG. 1 is a flowchart illustrating a method for manufacturing a variable resistance structure according to exemplary embodiments.

[0060] FIG. 2 is a plan view illustrating a method for manufacturing a variable resistance structure according to exemplary embodiments.

[0061] Figure 3 is a side view of the workpiece of Figure 2.

[0062] FIG. 4 is a plan view illustrating a method of manufacturing a variable resistance structure according to exemplary embodiments.

[0063] FIG. 5 is a plan view of a variable resistance structure (VRS) according to exemplary embodiments.

[0064] FIG. 6 is a side view of a variable resistance structure (VRS) according to exemplary embodiments.

[0065] Figure 7 is a cross-sectional view taken along the cutting line 5A-5A' of Figure 5.

[0066]

[0067] Referring to FIGS. 1 to 3, at P110, a variable resistance film (VF) can be formed on a conductive foil (CF).

[0068] The conductive foil (CF) may include a conductive material. The conductive foil (CF) may include, for example, a metal. The conductive foil (CF) may include, for example, aluminum. The conductive foil (CF) may include, for example, copper. The conductive foil (CF) may also include, for example, any one of gold, silver, nickel, tungsten, iron, bronze, brass, nickel alloys such as nickel chromium alloys, silicon steel, tungsten alloys, stainless steel, beryllium copper, and tantalum alloys.

[0069] A variable resistive film (VF) may include a variable resistive material. The variable resistive material may have resistivity characteristics (or conductance characteristics) that are temperature-dependent (i.e., change with temperature). The variable resistive material may be in an insulating state with high conductance and resistivity at temperatures below the transition temperature, and may be in a metallic state with high conductance and low resistivity at temperatures above the transition temperature.

[0070] According to exemplary embodiments, the conductance of the variable resistive material at a temperature above the transition temperature of the variable resistive material may be different from the conductance of the variable resistive material at a temperature below the transition temperature of the variable resistive material. According to exemplary embodiments, the conductance of the variable resistive material at a temperature above the transition temperature of the variable resistive material may be greater than the conductance of the variable resistive material at a temperature below the transition temperature of the variable resistive material.

[0071] According to the paper "Thermochromic VO2 thin films: A review on progress in solution processing methods" by D. Brassard, S. Fourmaux, and MA El Khakani (2010), which describes the resistance (or conductance) change of tunable materials, the change ratio of the resistance of VO2 thin films can be in the range of 2-3 times, or even up to about 100 times or more. The conductance and resistivity of these transition metal-based tunable materials can vary depending on the thickness, crystal structure, and doping state of the sample.

[0072] According to exemplary embodiments, the conductance of the variable resistive material at a temperature above the transition temperature of the variable resistive material may be at least about two times the conductance of the variable resistive material at a temperature below the transition temperature of the variable resistive material. According to exemplary embodiments, the conductance of the variable resistive material at a temperature above the transition temperature of the variable resistive material may be at least about three times the conductance of the variable resistive material at a temperature below the transition temperature of the variable resistive material. According to exemplary embodiments, the conductance of the variable resistive material at a temperature above the transition temperature of the variable resistive material may be at most about five times the conductance of the variable resistive material at a temperature below the transition temperature of the variable resistive material. According to exemplary embodiments, the conductance of the variable resistive material at a temperature above the transition temperature of the variable resistive material may be at most about four times the conductance of the variable resistive material at a temperature below the transition temperature of the variable resistive material.

[0073] According to exemplary embodiments, the conductance of the variable resistance material at a temperature exceeding the transition temperature of the variable resistance material may be several tens of times the conductance of the variable resistance material at a temperature below the transition temperature of the variable resistance material. According to exemplary embodiments, the conductance of the variable resistance material at a temperature exceeding the transition temperature of the variable resistance material may be at least one hundred times the conductance of the variable resistance material at a temperature below the transition temperature of the variable resistance material.

[0074] According to exemplary embodiments, the resistivity of the variable resistive material at a temperature below the transition temperature of the variable resistive material may be different from the resistivity of the variable resistive material at a temperature above the transition temperature of the variable resistive material. According to exemplary embodiments, the resistivity of the variable resistive material at a temperature below the transition temperature of the variable resistive material may be greater than the resistivity of the variable resistive material at a temperature above the transition temperature of the variable resistive material.

[0075] According to exemplary embodiments, the resistivity of the variable resistive material at a temperature below the transition temperature of the variable resistive material may be at least about two times the resistivity of the variable resistive material at a temperature above the transition temperature of the variable resistive material. According to exemplary embodiments, the resistivity of the variable resistive material at a temperature below the transition temperature of the variable resistive material may be at least about three times the resistivity of the variable resistive material at a temperature above the transition temperature of the variable resistive material. According to exemplary embodiments, the resistivity of the variable resistive material at a temperature below the transition temperature of the variable resistive material may be at most about five times the resistivity of the variable resistive material at a temperature above the transition temperature of the variable resistive material. According to exemplary embodiments, the resistivity of the variable resistive material at a temperature below the transition temperature of the variable resistive material may be at most about four times the resistivity of the variable resistive material at a temperature above the transition temperature of the variable resistive material.

[0076] According to exemplary embodiments, the resistivity of the variable resistivity material at a temperature below the transition temperature of the variable resistivity material may be about several tens of times greater than the resistivity of the variable resistivity material at a temperature above the transition temperature of the variable resistivity material. According to exemplary embodiments, the resistivity of the variable resistivity material at a temperature below the transition temperature of the variable resistivity material may be more than one hundred times greater than the resistivity of the variable resistivity material at a temperature above the transition temperature of the variable resistivity material.

[0077] According to exemplary embodiments, the variable resistance film (VF) may include, for example, a transition metal oxide. The variable resistance film (VF) may include, for example, a vanadium oxide such as VO2 and V2O3, a nickel oxide such as NiO, a manganese oxide such as MnO, La 1-x Ca x Mn O3It may include lanthanum calcium manganese oxides such as TiO2, titanium oxides such as Fe3O4, copper oxides such as CU2O, strontium ruthenium oxides such as SrRuO, ruthenium oxides such as RuO2, iridium oxides such as IrO2, and chromium oxides such as CR2O3.

[0078] Among these, the transition temperature of VO2 is approximately 341 K (i.e., approximately 68°C), which is relatively close to room temperature, making it easy to utilize its variable resistance characteristics. Furthermore, VO2 is advantageous for forming variable resistance films (VFs) due to its fast transition rate between metallic and insulating states, reversible state transitions, diverse tunability through doping and alloying, ease of thin film formation, and thermodynamic stability.

[0079] Unlike VO2, the transition temperature of V2O3 is about 150 K (i.e., about -123°C). Nickel oxides have a transition temperature of about 473 K or higher, manganese oxides have a transition temperature of about 391 K or higher, lanthanum calcium manganese oxides have a transition temperature in the range of about 173 K to about 473 K, iron oxides have a transition temperature of 120 K, strontium ruthenium oxides have a transition temperature of 80 K, and chromium oxides have a transition temperature of about 673 K. Pure titanium oxide does not exhibit a metal-to-insulator transition, and its transition temperature is determined by doping. Copper oxide, ruthenium oxide, and iridium oxide do not have a clear transition temperature.

[0080] A variable resistance film (VF) can be formed by liquid coating, including, for example, spin coating, slot die coating, dipping coating, spray coating, etc. Liquid coating can include applying an aqueous solution containing a variable resistance material, such as VO2, to a conductive foil (CF) and performing a drying process to remove a solvent of the aqueous solution.

[0081] The variable resistance film (VF) may be formed by CVD, such as plasma-enhanced CVD (Chemical Vapor Deposition), low-pressure CVD, or atmospheric-pressure CVD. The variable resistance film (VF) may also be formed by PVD (Physical Vapor Deposition), such as evaporation, sputtering, or ion plating. The variable resistance film (VF) may also be formed by sol-gel coating and hydrothermal processes.

[0082] A variable resistance film (VF) can partially cover a conductive foil (CF). The variable resistance film (VF) can partially overlap with the conductive foil (CF). The variable resistance film (VF) can expose a portion of the conductive foil (CF). The variable resistance film (VF) can expose an edge portion of the conductive foil (CF) in the longitudinal direction (LD). Here, the length of the conductive foil (CF) in the longitudinal direction (LD) can be greater than the length of the conductive foil (CF) in the transverse direction (TD). The longitudinal direction (LD) and the transverse direction (TD) can be substantially parallel to the conductive foil (CF). The longitudinal direction (LD) and the transverse direction (TD) can be substantially perpendicular to each other.

[0083]

[0084] Next, referring to FIGS. 1, 2 and 4, at P120, the laminated structure (SS) of the conductive foil (CF) and the variable resistance film (VF) can be cut so that a plurality of laminated structures (SS') having a width smaller than the laminated structure (SS) are provided. By cutting the laminated structure (SS), a plurality of laminated structures (SS') separated from each other in the transverse direction (TD) can be provided. The conductive foil (CF) of each of the plurality of laminated structures (SS') can include a portion covered by the variable resistance film (VF) and a portion not covered by the variable resistance film (VF) (i.e., an exposed portion).

[0085]

[0086] Next, referring to FIGS. 1, 5, 6 and 7, at P130, an insulating layer (IL) can be provided on a variable resistance film (VF).

[0087] The insulating layer (IL) may include an insulating material. The insulating layer (IL) may include, for example, a separator. According to exemplary embodiments, the insulating layer (IL) may include a polyolefin such as polypropylene and polyethylene. According to exemplary embodiments, the insulating layer (IL) may include a polyolefin coated with alumina (Al2O3) or silica (SiO2). According to exemplary embodiments, the insulating layer (IL) may also include a cellulose-based separator. According to exemplary embodiments, the insulating layer (IL) may include polyimide, polyethylene terephthalate, polypropylene, polycarbonate, polyvinyl chloride, Teflon, ethylene-propylene-diene-monomer, silicone, and polyethylene naphthalate, and aramid.

[0088] The insulating layer (IL) can be in contact with the conductive foil (CF). The insulating layer (IL) can surround the conductive foil (CF). The insulating layer (IL) can be in contact with the variable resistance film (VF). The insulating layer (IL) can surround the variable resistance film (VF).

[0089] An insulating layer (IL) may partially cover a conductive foil (CF). The insulating layer (IL) may include a first opening exposing a contact portion (CFC) of the conductive foil (CF). By adjusting the size of the first opening, the area of ​​the contact portion (CFC) may be adjusted. The insulating layer (IL) may be configured to prevent short circuits between other portions of the conductive foil (CF) excluding the contact portion (CFC) and elements outside the variable resistance structure (VRS).

[0090] An insulating layer (IL) may partially cover a variable resistor film (VF). The insulating layer (IL) may include a second opening that exposes a contact portion (VFC) of the variable resistor film (VF). By adjusting the size of the second opening, the area of ​​the contact portion (VFC) may be adjusted. The insulating layer (IL) may be configured to prevent short circuits between other portions of the variable resistor film (VF) excluding the contact portion (VFC) and elements outside the variable resistor structure (VRS).

[0091] According to exemplary embodiments, a variable resistor structure (VRS) can implement a temperature-dependent short circuit between a first conductive element and a second conductive element. When the temperature of the variable resistor structure rises above a transition temperature while the contact portion (CFC) of the conductive foil (CF) is in contact with the first conductive element and the contact portion (VFC) of the variable resistor structure (VRS) is in contact with the second conductive element, the first conductive element and the second conductive element can be short-circuited.

[0092]

[0093] (Examples 3 and 4)

[0094] FIG. 8 is a flowchart illustrating a method for manufacturing an electrode assembly according to exemplary embodiments.

[0095] FIGS. 9 to 16 are drawings for explaining a method of manufacturing an electrode assembly according to exemplary embodiments, more specifically, as follows.

[0096] Figure 9 is a plan view of the positive electrode (PE).

[0097] Figure 10 is a side view of the positive electrode (PE).

[0098] Figure 11 is a plan view showing the anode (PE, see Figure 10) and the separator (SRS).

[0099] Figure 12 is a side view showing the positive electrode (PE) and the separator (SRS).

[0100] Figure 13 is a plan view showing the anode (PE, see Figure 12), separator (SRS), and variable resistance structure (VRS).

[0101] Figure 14 is a side view showing the anode (PE, see Figure 12), the separator (SRS), and the variable resistance structure (VRS).

[0102] FIG. 15 is a plan view of an electrode assembly (EA) according to exemplary embodiments.

[0103] FIG. 16 is a side view of an electrode assembly (EA) according to exemplary embodiments.

[0104] Referring to FIGS. 8 to 10, a positive electrode (PE) can be provided at P210. The positive electrode (PE) can be provided by a die coating process, a drying process, a roll pressing process, a slitting process, and a notching process. The positive electrode (PE) can include a positive electrode current collector (PSB), a first positive electrode active material layer (PC1), and a first positive electrode active material layer (PC2).

[0105] The thickness of the positive current collector (PSB) may range from about 3 μm to about 500 μm. The positive current collector (PSB) may not cause chemical changes in the secondary battery to be ultimately manufactured and may have high conductivity. The positive current collector (PSB) may include, for example, any one of stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum. The positive current collector (PSB) may also include stainless steel surface-treated with carbon, nickel, titanium, silver, etc. The surface of the positive current collector (PSB) may include a micro-roughened structure to increase the adhesion of the active material. The shape of the positive current collector (PSB) may include any one of a film, a sheet, a foil, a net, a porous material, a foam, and a non-woven fabric.

[0106] The first positive electrode active material layer (PC1) may be on the first surface of the positive electrode current collector (PSB). The second positive electrode active material layer (PC2) may be on the second surface of the positive electrode current collector (PSB). The first surface of the positive electrode current collector (PSB) and the second surface of the positive electrode current collector (PSB) are opposite to each other. The first positive electrode active material layer (PC1) and the second positive electrode active material layer (PC2) may include, for example, a positive electrode active material.

[0107] A cathode active material is a material capable of causing an electrochemical reaction. The cathode active material may be a lithium transition metal oxide. Examples of the cathode 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; chemical formula LiNi 1-y M y Lithium nickel oxide expressed as O2 (wherein, M is any one of 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+zN i 0.4 Mn 0.4 Co 0.2 Li like O2 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 of Al, Mg, Cr, Ti, Si, and Y, and A is any one of F, P, and Cl) lithium nickel cobalt manganese composite oxide; and chemical formula Li 1+x M 1-y M' y PO4-z X z (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, and 0≤z≤0.1) and may include one of the olivine-based lithium metal phosphates.

[0108] A portion of the positive electrode current collector (PSB) to which the first positive electrode active material layer (PC1) and the second positive electrode active material layer (PC2) are applied (i.e., overlaps the first positive electrode active material layer (PC1) and the second positive electrode active material layer (PC2)) may be referred to as a holding portion, and a portion of the positive electrode current collector (PSB) to which the first positive electrode active material layer (PC1) and the second positive electrode active material layer (PC2) are not applied (i.e., is spaced apart from the first positive electrode active material layer (PC1) and the second positive electrode active material layer (PC2)) may be referred to as a non-conducting portion. The non-conducting portion of the positive electrode current collector (PSB) may be a positive electrode tab (PT) of the positive electrode current collector (PSB). The positive electrode tab (PT) may be an external connection terminal of the positive electrode (PE). The positive electrode tab (PT) may have a width smaller than each of the first positive electrode active material layer (PC1) and the second positive electrode active material layer (PC2).

[0109]

[0110] Next, referring to FIGS. 8, 11, and 12, a separator (SRS) may be provided on the anode (PE). According to exemplary embodiments, the separator (SRS) may include a polyolefin such as polypropylene and polyethylene. According to exemplary embodiments, the separator (SRS) may include a polyolefin coated with alumina (Al2O3) or silica (SiO2). According to exemplary embodiments, the separator (SRS) may also include a cellulose-based separator.

[0111] The separator (SRS) may cover the first positive electrode active material layer (PC1). The separator (SRS) may have a larger area than the first positive electrode active material layer (PC1) to prevent short circuiting between the positive electrode (PE) and the subsequent negative electrode (NE, see FIG. 16). The width of the separator (SRS) may be larger than the width of the first positive electrode active material layer (PC1). The length of the separator (SRS) may be larger than the length of the first positive electrode active material layer (PC1).

[0112]

[0113] Next, referring to FIGS. 7, 8, 13, and 14, a variable resistance structure (VRS) can be provided on the separator (SRS) and the anode (PE). The variable resistance structure (VRS) can be provided through the method described with reference to FIGS. 1 to 7.

[0114] According to exemplary embodiments, the conductive foil (CF) of the variable resistor structure (VRS) can face the anode (PE) (more specifically, the anode tab (PT)). According to exemplary embodiments, the contact portion (CFC) of the conductive foil (CF) of the variable resistor structure (VRS) can contact the anode (PE) (more specifically, the anode tab (PT)).

[0115] According to exemplary embodiments, a conductive foil (CF) of a variable resistance structure (VRS) may be fixed to an anode (PE) (more specifically, an anode tab (PT)) by an adhesive. The adhesive may be partially provided between the conductive foil (CF) and the anode tab (PT) so as not to prevent a short circuit between the conductive foil (CF) and the anode tab (PT). That is, an area of ​​the anode tab (PT) to which the adhesive is applied may be smaller than an area of ​​the conductive foil (CF) in contact with the anode tab (PT).

[0116] The variable resistance film (VF) may be separated from the positive electrode tab (PT) by a conductive foil (CF). The variable resistance film (VF) may not be in contact with the positive electrode tab (PT). The laminated structure of the positive electrode (PE) and the separator (SRS) may be transferred to the variable resistance structure (VRS). Accordingly, the variable resistance structure (VRS) may include a step shape.

[0117]

[0118] Next, referring to FIGS. 7, 8, 15, and 16, a negative electrode (NE) can be provided on the separator (SRS) and the variable resistance structure (VRS). The negative electrode (NE) can be provided by a die coating process, a drying process, a roll pressing process, a slitting process, and a notching process. The negative electrode (NE) can include a negative current collector (NSB), a first negative electrode active material layer (NC1), and a second negative electrode active material layer (NC2).

[0119] The thickness of the negative current collector (NSB) may be in the range of about 3 ㎛ to about 500 ㎛. The negative current collector (NSB) may not cause a chemical change in the secondary battery to be ultimately manufactured and may have high conductivity. The negative current collector (NSB) may include any one of copper, stainless steel, aluminum, nickel, titanium, sintered carbon, and an aluminum-cadmium alloy. The negative current collector (NSB) may also include stainless steel surface-treated with carbon, nickel, titanium, silver, etc. The surface of the negative current collector (NSB) may include a micro-roughened structure to increase the adhesion of the active material. The shape of the negative current collector (NSB) may include any one of a film, a sheet, a foil, a net, a porous material, a foam, and a non-woven fabric.

[0120] The first negative active material layer (NC1) may be on a first surface of a negative current collector (NSB). The second negative active material layer (NC2) may be on a second surface of the negative current collector (NSB). The first surface of the negative current collector (NSB) and the second surface of the negative current collector (NSB) are opposite to each other. The first negative active material layer (NC1) and the second negative active material layer (NC2) may include, for example, a negative active material.

[0121] The negative electrode active material may include carbon, such as non-graphitizable carbon, graphitic carbon, etc. The negative electrode active material may include, for example, Li x Fe2O3(0≤x≤1), LixWO2(0≤x≤1), Sn x Me 1-x Me' y O z (wherein Me is any one of Mn, Fe, Pb and Ge, and Me' is any one of Al, B, P, Si, elements of group 1, 2 and 3 of the periodic table and halogens; 0 <x≤1 이고; 1≤y≤3 이며; 1≤z≤8) 등의 금속 복합 산화물을 포함할 수 있다. 음극 활물질은, 예컨대, 리튬 금속; 리튬 합금; 규소계 합금; 및 주석계 합금 중 어느 하나를 포함할 수 있다. 음극 활물질은, 예컨대, SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4및 Bi2O5등의 금속 산화물을 포함할 수 있다. 음극 활물질은, 예컨대, 폴리아세틸렌 등의 도전성 고분자; Li-Co-Ni 계 재료 등을 포함할 수도 있다.

[0122] A portion of the negative current collector (NSB) to which the first negative active material layer (NC1) and the second negative active material layer (NC2) are applied (i.e., overlapping the first negative active material layer (NC1) and the second negative active material layer (NC2)) may be referred to as a holding portion, and a portion of the negative current collector (NSB) to which the first negative active material layer (NC1) and the second negative active material layer (NC2) are not applied (i.e., spaced apart from the first negative active material layer (NC1) and the second negative active material layer (NC2)) may be referred to as a non-conductive portion. The non-conductive portion of the negative current collector (NSB) may be a negative tab (NT) of the negative current collector (NSB). The negative tab (NT) may be an external connection terminal of the negative electrode (NE). The negative tab (NT) may have a width smaller than each of the first negative active material layer (NC1) and the second negative active material layer (NC2).

[0123] According to exemplary embodiments, the second negative active material layer (NC2) may face the insulating layer (IL) and the variable resistance film (VF). According to exemplary embodiments, the second negative active material layer (NC2) may be in contact with the insulating layer (IL) and the variable resistance film (VF). According to exemplary embodiments, the second negative active material layer (NC2) may be in contact with the contact portion (VFC) of the variable resistance film (VF). The variable resistance structure (VRS) may include a portion on the positive tab (PT) and a portion between the negative electrode (NE) and the separator (SRS).

[0124] The second negative electrode active material layer (NC2) can be spaced apart from the conductive foil (CF) with at least one of the insulating layer (IL) and the variable resistance film (VF) therebetween. Accordingly, a short circuit between the second negative electrode active material layer (NC2) and the conductive foil (CF) can be prevented, and insulation between the positive electrode (PE) and the negative electrode (NE) can be maintained before the temperature of the variable resistance film (VF) is increased above the transition temperature for a short circuit test. When the temperature of the variable resistance film (VF) is increased above the transition temperature, a short circuit path including the second negative electrode active material layer (NC2) - the variable resistance film (VF) - the conductive foil (CF) - the positive electrode tab (PT) can be provided.

[0125]

[0126] (Example 5)

[0127] FIG. 17 is a side view of an electrode assembly (EA') according to other exemplary embodiments.

[0128] Referring to FIGS. 7 and 17, the electrode assembly (EA') may include an anode (PE), a cathode (NE), a separator (SRS), and a variable resistance structure (VRS).

[0129] The electrode assembly (EA') is substantially the same as the electrode assembly (EA) of FIG. 16, except for the orientation of the variable resistance structure (VRS). The variable resistance structure (VRS) of the electrode assembly (EA') may include a portion on the positive electrode tab (PT) and a portion between the negative electrode (NE) and the separator (SRS). The laminated structure of the positive electrode (PE) and the separator (SRS) may be transferred to the variable resistance structure (VRS). Accordingly, the variable resistance structure (VRS) may include a step shape.

[0130] According to exemplary embodiments, the positive electrode tab (PT) may face the insulating layer (IL) and the variable resistance film (VF). According to exemplary embodiments, the positive electrode tab (PT) may be in contact with the insulating layer (IL) and the variable resistance film (VF). According to exemplary embodiments, the positive electrode tab (PT) may be in contact with the contact portion (VFC, see FIG. 5) of the variable resistance film (VF).

[0131] According to exemplary embodiments, the variable resistance film (VF) may be fixed to the positive electrode (PE) (more specifically, the positive electrode tab (PT)) by an adhesive. The adhesive may be partially provided between the variable resistance film (VF) and the positive electrode tab (PT) so as not to prevent a short circuit between the variable resistance film (VF) and the positive electrode tab (PT) when the variable resistance film (VF) is in a metallic state. That is, the area of ​​the positive electrode tab (PT) to which the adhesive is applied may be smaller than the area of ​​the variable resistance film (VF) in contact with the positive electrode tab (PT).

[0132] According to exemplary embodiments, the conductive foil (CF) of the variable resistance structure (VRS) may face the second negative active material layer (NC2). According to exemplary embodiments, the contact portion (CFC) of the conductive foil (CF) may be in contact with the second negative active material layer (NC2).

[0133] The positive electrode tab (PT) can be spaced from the conductive foil (CF) with at least one of the insulating layer (IL) and the variable resistance film (VF) interposed therebetween. Accordingly, a short circuit between the positive electrode tab (PT) and the conductive foil (CF) can be prevented, and insulation between the positive electrode (PE) and the negative electrode (NE) can be maintained before the temperature of the variable resistance film (VF) is increased above the transition temperature for a short circuit test. When the temperature of the variable resistance film (VF) is increased above the transition temperature, a short circuit path including the second negative electrode active material layer (NC2) - conductive foil (CF) - variable resistance film (VF) - positive electrode tab (PT) can be provided.

[0134]

[0135] (Example 6)

[0136] FIG. 18 is a side view of an electrode assembly (EA") according to other exemplary embodiments.

[0137] Referring to FIGS. 7 and 18, the electrode assembly (EA") may include an anode (PE), a cathode (NE), a separator (SRS), and a variable resistance structure (VRS).

[0138] The electrode assembly (EA") is substantially the same as the electrode assembly (EA) of FIG. 16, except for the location of the variable resistance structure (VRS). The variable resistance structure (VRS) of the electrode assembly (EA") may include a portion on the negative electrode tab (NT) and a portion between the positive electrode (PE) and the separator (SRS). The laminated structure of the negative electrode (NE) and the separator (SRS) may be transferred to the variable resistance structure (VRS). Accordingly, the variable resistance structure (VRS) may include a step shape.

[0139] According to exemplary embodiments, the first positive electrode active material layer (PC1) may face the insulating layer (IL) and the variable resistance film (VF). According to exemplary embodiments, the first positive electrode active material layer (PC1) may be in contact with the insulating layer (IL) and the variable resistance film (VF). According to exemplary embodiments, the first positive electrode active material layer (PC1) may be in contact with the contact portion (VFC) of the variable resistance film (VF).

[0140] According to exemplary embodiments, the conductive foil (CF) of the variable resistance structure (VRS) may face the cathode (NE) (more specifically, the cathode tab (NT)). According to exemplary embodiments, the contact portion (CFC) of the conductive foil (CF) may be in contact with the cathode (NE) (more specifically, the cathode tab (NT)).

[0141] According to exemplary embodiments, a conductive foil (CF) of a variable resistance structure (VRS) may be fixed to a negative electrode (NE) (more specifically, a negative tab (NT)) by an adhesive. The adhesive may be partially provided between the conductive foil (CF) and the negative tab (NT) so as not to prevent a short circuit between the conductive foil (CF) and the negative tab (NT). That is, an area of ​​the negative tab (NT) to which the adhesive is applied may be smaller than an area of ​​the conductive foil (CF) that is in contact with the negative tab (NT). A variable resistance film (VF) may be spaced apart from the negative tab (NT) with the conductive foil (CF) interposed therebetween. The variable resistance film (VF) may not be in contact with the negative tab (NT).

[0142] The first positive electrode active material layer (PC1) can be spaced apart from the conductive foil (CF) with at least one of the insulating layer (IL) and the variable resistance film (VF) therebetween. Accordingly, a short circuit between the first positive electrode active material layer (PC1) and the conductive foil (CF) can be prevented, and insulation between the positive electrode (PE) and the negative electrode (NE) can be maintained before the temperature of the variable resistance film (VF) is increased above the transition temperature for a short circuit test. When the temperature of the variable resistance film (VF) is increased above the transition temperature, a short circuit path including the first positive electrode active material layer (PC1) - the variable resistance film (VF) - the conductive foil (CF) - the negative electrode tab (NT) can be provided.

[0143]

[0144] (Example 7)

[0145] FIG. 19 is a plan view of an electrode assembly (EA"') according to exemplary embodiments.

[0146] Figure 20 is a cross-sectional view taken along the cutting line 19A-19A' of Figure 19.

[0147] Fig. 21 is a cross-sectional view taken along the cutting line 19B-19B' of Fig. 19.

[0148] FIG. 22 is a front view of a variable resistance structure according to exemplary embodiments.

[0149] Referring to FIGS. 7, 19 to 22, the electrode assembly (EA") may include an anode (PE), a cathode (NE), a separator (SRS), and a variable resistance structure (VRS).

[0150] The electrode assembly (EA") is substantially the same as the electrode assembly (EA) of FIG. 16, except for the location of the variable resistance structure (VRS). The variable resistance structure (VRS) can be spaced from the positive electrode tab (PT). The variable resistance structure (VRS) can not overlap the positive electrode tab (PT). The variable resistance structure (VRS) can overlap edges of the positive electrode (PE). The variable resistance structure (VRS) can be spaced from the negative electrode tab (NT). The variable resistance structure (VRS) can not overlap the negative electrode tab (NT). The variable resistance structure (VRS) can overlap edges of the negative electrode (NE).

[0151] That is, unlike the embodiments of FIGS. 16 to 18, where the variable resistance structure (VRS) is at the end in the longitudinal direction of the positive electrode (PE) and the negative electrode (NE) (or the protruding direction of the positive tab (PT) and the negative tab (NT)), in the example of FIG. 19, the variable resistance structure (VRS) can overlap with an edge that is parallel to the longitudinal direction of the positive electrode (PE) and the negative electrode (NE) (or the protruding direction of the positive tab (PT) and the negative tab (NT)).

[0152] According to exemplary embodiments, the variable resistance structure (VRS) can be bent in an approximately C-shape. According to exemplary embodiments, the variable resistance structure (VRS) of the electrode assembly (EA"') can include a portion between the negative electrode (NE) and the separator (SRS). The portion of the variable resistance structure (VRS) between the negative electrode (NE) and the separator (SRS) may not be separated from the negative electrode (NE) without a separate adhesive. The variable resistance structure (VRS) can include a portion on the second positive electrode active material layer (PC2). The portion of the variable resistance structure (VRS) on the second positive electrode active material layer (PC2) may be fixed to the second positive electrode active material layer (PC2) by an adhesive or may be fixed by laminating an additional separator.

[0153] According to exemplary embodiments, the conductive foil (CF) may face the second positive electrode active material layer (PC2) of the positive electrode (PE). According to exemplary embodiments, the contact portion (CFC) of the conductive foil (CF) may be in contact with the second positive electrode active material layer (PC2) of the positive electrode (PE). The insulating layer (IL) may include a portion between the conductive foil (CF) and the second positive electrode active material layer (PC2).

[0154] The conductive foil (CF) may not be in contact with the second negative electrode active material layer (NC2) of the negative electrode (NE). The conductive foil (CF) may be spaced apart from the second negative electrode active material layer (NC2) with at least one of an insulating layer (IL) and a variable resistance film (VF) interposed therebetween. The conductive foil (CF) may include a first portion that is interposed between the separator (SRS) and the negative electrode (NE) and is spaced apart from the second negative electrode active material layer (NC2) of the negative electrode (NE) with the insulating layer (IL) and the variable resistance film (VF) interposed therebetween. The conductive foil (CF) may include a second portion that is interposed between the separator (SRS) and the negative electrode (NE) and is spaced apart from the second negative electrode active material layer (NC2) of the negative electrode (NE) with only the variable resistance film (VF) interposed therebetween.

[0155] According to exemplary embodiments, the variable resistance film (VF) may face the second negative electrode active material layer (NC2) of the negative electrode (NE). According to exemplary embodiments, the contact portion (VFC) of the variable resistance film (VF) may be in contact with the second negative electrode active material layer (NC2) of the negative electrode (NE).

[0156] A short circuit between the second negative active material layer (NC2) and the conductive foil (CF) below the transition temperature can be prevented by at least one of the insulating layer (IL) and the variable resistance film (VF). When the temperature of the variable resistance film (VF) rises above the transition temperature, a short circuit path including the first positive active material layer (PC1) - conductive foil (CF) - variable resistance film (VF) - second negative active material layer (NC2) can be provided.

[0157]

[0158] (Example 8)

[0159] FIG. 23 is a side view showing a battery cell (121) according to exemplary embodiments.

[0160] Fig. 24 is an exploded perspective view of a battery cell (121) according to exemplary embodiments.

[0161] Referring to FIG. 16, FIG. 23, and FIG. 24, a battery cell (121) may include a cell case (121C), an electrode assembly (121EA), a positive terminal (121P), and a negative terminal (121N). The battery cell (121) may further include an electrolyte.

[0162] According to exemplary embodiments, the battery cell (121) may be one of a cylindrical battery cell, a prismatic battery cell, and a pouch-type battery cell. The electrode assembly of the cylindrical battery cell is housed in a cylindrical metal can. The electrode assembly of the prismatic battery cell is housed in a prismatic metal can. The electrode assembly of the pouch-type battery cell is housed in a pouch case including an aluminum laminate sheet. Hereinafter, the technical idea of ​​the present invention will be described based on an example in which the battery cell (121) is a pouch-type battery cell. However, a person skilled in the art will easily arrive at an example in which the battery cell (121) is one of a cylindrical battery cell and a prismatic battery cell based on the description herein.

[0163] The electrode assembly (121EA) may be provided based on the electrode assembly (EA) of FIG. 16. More specifically, the electrode assembly (121EA) may be provided by stacking additional anodes (PE, see FIG. 16), additional cathodes (PE, see FIG. 16), and additional separators (SRS, see FIG. 16) on the electrode assembly (EA). The electrode assembly (121EA) may also be provided by stacking additional anodes (PE, see FIG. 16), additional cathodes (PE, see FIG. 16), and additional separators (SRS, see FIG. 16) on the electrode assemblies (EA', EA", EA"') of FIGS. 17, 18, and 19 instead of the electrode assembly (EA) of FIG. 16.

[0164] Accordingly, the electrode assembly (121EA) may include a plurality of anodes (PE), a plurality of cathodes (NE), a plurality of separators (SRS) interposed between adjacent ones of the plurality of anodes (PE) and the plurality of cathodes (NE), and a variable resistance structure (VRS) in contact with one of the plurality of anodes (PE) and one of the plurality of cathodes (NE). The electrode assembly (121EA) may include only one variable resistance structure (VRS), or may include two or more variable resistance structures (VRS).

[0165] Each of the plurality of anodes (PE) of the electrode assembly (121EA) may include an anode tab (PT). The anode tab (PT) of each of the plurality of anodes (PE) of the electrode assembly (121EA) may be short-circuited with the anode terminal (121P). The anode tab (PT) of each of the plurality of anodes of the electrode assembly (121EA) may be welded with the anode terminal (121P).

[0166] Each of the plurality of cathodes (NE) of the electrode assembly (121EA) may include a cathode tab (NT). The cathode tab (NT) of each of the plurality of cathodes (NE) of the electrode assembly (121EA) may be short-circuited with the cathode terminal (121N). The cathode tab (NT) of each of the plurality of cathodes (NE) of the electrode assembly (121EA) may be welded with the cathode terminal (121N).

[0167] The cell case (121C) may include an inner resin layer, a metal layer, and an outer resin layer. An adhesive and a corrosion-preventing layer may further be provided between the inner resin layer and the metal layer and between the outer resin layer and the metal layer.

[0168] The inner resin layer may have heat-sealing properties and may be referred to as a sealant layer. The inner resin layer enables sealing of the cell case (121C). The inner resin layer may include a polyolefin-based resin, such as polypropylene and polyethylene. The metal layer may include one of 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 ingress and egress of gases from the cell case (121C). The outer resin layer may be a surface protection layer. The outer resin layer may include a material having wear resistance and heat resistance, such as a nylon resin.

[0169] The cell case (121C) may be provided by joining a first cell case (121C1) and a second cell case (121C2). The first cell case (121C1) may be substantially flat. The first cell case (121C1) may not include a receiving portion. The second cell case (121C2) may include a receiving portion (121R). The receiving portion (121R) may be formed by a pouch forming process. The receiving portion (121R) is a portion of the second cell case (121C2) formed into a bowl shape to receive the electrode assembly (121EA).

[0170] The terrace (121T) of the second cell case (121C2) may surround the receiving portion (121R). The terrace (121T) of the second cell case (121C2) may be joined to the edge of the first cell case (121C1), thereby providing a cell case (121C). The sealing portion (121CS) may be provided by joining the first and second cases (121C1, 121C2). That is, the sealing portion (121CS) may be a joining portion of the first and second cases (121C1, 121C2).

[0171] As in the example of Fig. 2, when the receiving portion is formed only in the second cell case (121C2) among the first and second cases (121C1, 121C2), the sealing portion (121CS) may be connected to the first main surface (121FS1). The sealing portion (121CS) may include a portion that forms a plane with the first main surface (121FS1).

[0172] The cell case (121C) may have an approximately rectangular parallelepiped shape, and the first main surface (121FS1) and the second main surface (121FS2) of the cell case (121C) may be widest surfaces of the cell case (121C). The first main surface (121FS1) and the second main surface (121FS2) may be substantially parallel to at least one of the electrode assembly (121EA) or the plurality of positive electrodes and the plurality of negative electrodes included in the electrode assembly (121EA). The first main surface (121FS1) and the second main surface (121FS2) may be opposite to each other. The first main surface (121FS1) and the second main surface (121FS2) may be substantially perpendicular to the X direction, but are not limited thereto.

[0173] An insulating tape (121I) may be applied on the positive terminal (121P) and the negative terminal (121N). The positive terminal (121P) and the negative terminal (121N) may protrude outside the cell case (121C). The positive terminal (121P) and the negative terminal (121N) may protrude in the Y direction from the cell case (121C). Accordingly, the resulting voltage and current of the battery cell (121) may be output through the positive terminal (121P) and the negative terminal (121N). The positive terminal (121P) may be a positive lead. The negative terminal (121N) may be a negative lead. The Y direction may be substantially perpendicular to the X direction.

[0174]

[0175] (Example 9)

[0176] FIG. 25 is a perspective view showing a battery cell assembly (120) according to exemplary embodiments.

[0177] Figure 26 is a cross-sectional view taken along the cutting line 25A-25A' of Figure 25.

[0178] Referring to FIGS. 25 and 26, the battery cell assembly (120) may include a plurality of battery cells (121, 121'), pads (122), a first integrated circuit assembly (123), a second integrated circuit assembly (124), and an FFC (Flexible Flat Cable) assembly (127).

[0179] The battery cell (121) is substantially the same as that described with reference to FIGS. 23 and 24. The location of the battery cell (121) can be determined according to the target internal short-circuit occurrence location scenario.

[0180] Each of the battery cells (121') is substantially the same as the battery cell (121) described with reference to FIGS. 23 and 24, except that it does not include a variable resistance structure (VRS, see FIG. 7). The plurality of battery cells (121, 121') may be arranged in the X direction. The plurality of battery cells (121, 121') may be joined by, for example, an adhesive. According to exemplary embodiments, the battery cell assembly (120) may include normal battery cells (121') and a battery cell (121) including a variable resistance structure (VRN, see FIG. 7) to simulate an internal short circuit.

[0181] A plurality of battery cells (121, 121') can form a plurality of banks (BNK1, BNK2, BNK3, BNK4, BNK5, BNK6, BNK7, BNK8, BNK9, BNK10, BNK11, BNK12, BNK13, BNK14, BNK15, BNK16). For example, some (e.g., three) battery cells (121') can be connected in parallel to each other and form a bank (BNK1). For example, some battery cells (121') can be connected in parallel to each other and form a bank (BNK2). For example, some battery cells (121') can be connected in parallel to each other and form a bank (BNK3). For example, some battery cells (121') can be connected in parallel to each other and form a bank (BNK4). For example, some battery cells (121, 121') may be connected in parallel to each other and may form a bank (BNK5). For example, some battery cells (121') may be connected in parallel to each other and may form a bank (BNK6). For example, some battery cells (121') may be connected in parallel to each other and may form a bank (BNK7). For example, some battery cells (121') may be connected in parallel to each other and may form a bank (BNK8). For example, some battery cells (121') may be connected in parallel to each other and may form a bank (BNK9). For example, some battery cells (121') may be connected in parallel to each other and may form a bank (BNK10). For example, some battery cells (121') may be connected in parallel to each other and may form a bank (BNK11). For example, some battery cells (121') may be connected in parallel with each other and may form a bank (BNK12). For example, some battery cells (121') may be connected in parallel with each other and may form a bank (BNK13). For example, some battery cells (121') may be connected in parallel with each other and may form a bank (BNK14).For example, some battery cells (121') may be connected in parallel with each other and form a bank (BNK15). For example, some battery cells (121') may be connected in parallel with each other and form a bank (BNK16). A plurality of banks (BNK1) may be connected in series.

[0182] The resulting connection configuration of the plurality of battery cells (121, 121') may be referred to as 3-parallel-16-series (3P-16S), but this is for illustrative purposes only and does not limit the technical spirit of the present invention in any way. The number of series-connected banks and the number of battery cells (121, 121') included in the plurality of banks may be determined depending on the magnitude of the voltage and current to be output from the battery cell assembly (120).

[0183] The pads (122) can absorb swelling of the plurality of battery cells (121, 121'). Each of the pads (122) can include polyurethane (PU). Each of the pads (122) can include a refractory material such as silicone. As a non-limiting example, two of the plurality of banks (BNK1 to BNK16) can be interposed between adjacent pads (122).

[0184] A first integrated circuit assembly (123) may include an insulating frame (123F), a first integrated circuit, bus bars (123P, 123N), and an insulating cover (123C). A second integrated circuit assembly (124) may include an insulating frame (124F), a second integrated circuit, and an insulating cover (124C).

[0185] The first and second integrated circuit assemblies (123, 124) may include physical and functional components for providing electrical connections between the plurality of battery cells (121, 121'), outputting a resulting voltage of the plurality of battery cells (121, 121'), and measuring voltages (or currents) of nodes within a circuit comprised of the plurality of battery cells (121, 121').

[0186] The insulating frame (123F) may include an insulating material such as plastic. The insulating frame (123F) may cover the front of a plurality of battery cells (121, 121'). The insulating frame (123F) may support the first integrated circuit, bus bars (123P, 123N), and the insulating cover (123C).

[0187] The bus bar (123P) may be short-circuited to the positive leads (121P) of one or more battery cells (121, 121') of the first bank (BNK1), and the bus bar (123N) may be short-circuited to the negative leads (121N) of one or more battery cells (121, 121') of the last bank (BNK16). The bus bar (123P) may be welded to the positive leads (121P) of one or more battery cells (121') of the first bank (BNK1), and the bus bar (123N) may be welded to the negative leads (121N) of one or more battery cells (121') of the last bank (BNK16). The resulting voltage of a plurality of battery cells (121, 121') of a battery cell assembly (120) can be output through bus bars (123P, 123N). The bus bars (123P, 123N) can be fixed to an insulating frame (123F).

[0188] The first integrated circuit may be mounted on an insulating frame (123F). The positive leads (121P) and negative leads (121N) welded to each other may constitute nodes within the battery cell assembly (120). The first integrated circuit may be electrically connected to the nodes within the battery cell assembly (120) via a sensing plate or wire, and may be configured to measure the voltage of the nodes.

[0189] The insulating cover (123C) may include an insulating material such as plastic. The insulating cover (123C) may be fitted into the insulating frame (123F). The insulating cover (123F) may cover the first integrated circuit, thereby protecting the electrical components of the first integrated circuit assembly (123).

[0190] The insulating frame (124F) may include an insulating material such as plastic. The insulating frame (124F) may cover the rear of the plurality of battery cells (121, 121'). The insulating frame (124F) may support the first integrated circuit and the insulating cover (124C).

[0191] The second integrated circuit may be mounted on an insulating frame (124F). The second integrated circuit may be electrically connected to nodes within the battery cell assembly (120) via a sensing plate or wire, and may be configured to measure voltages of the nodes.

[0192] The first integrated circuit may be configured to measure voltages of nodes formed by positive leads (121P) of odd-numbered banks (BNK1, BNK3, BNK5, BNK7, BNK9, BNK11, BNK13, BNK15) and negative leads (121N) of even-numbered banks (BNK2, BNK4, BNK6, BNK8, BNK10, BNK12, BNK14, BNK16). The first integrated circuit may be configured to measure voltages of nodes formed by negative leads (121N) of odd-numbered banks (BNK1, BNK3, BNK5, BNK7, BNK9, BNK11, BNK13, BNK15) and positive leads (121P) of even-numbered banks (BNK2, BNK4, BNK6, BNK8, BNK10, BNK12, BNK14, BNK16).

[0193] The insulating cover (124C) may include an insulating material such as plastic. The insulating cover (124C) may be fitted to the insulating frame (124F). The insulating cover (124F) may cover the second integrated circuit, thereby protecting the electrical components of the second integrated circuit assembly (124).

[0194] The FFC assembly (127) can provide an electrical connection between the first integrated circuit of the first integrated circuit assembly (123) and the second integrated circuit of the second integrated circuit assembly (124). Accordingly, measurements such as temperature and voltage collected from the second integrated circuit of the second integrated circuit assembly (124) can be transmitted to the first integrated circuit of the first integrated circuit assembly (123) via the FFC assembly (127).

[0195]

[0196] (Example 10)

[0197] FIG. 27 is a plan view showing a battery pack (100) according to exemplary embodiments.

[0198] Referring to FIGS. 25 to 27, a battery pack (100) may include a pack housing (110), a plurality of battery cell assemblies (120, 120'), and cross beams (131). The battery pack (100) may be a final product mounted in an application such as a vehicle.

[0199] The pack housing (110) can provide a space for mounting a plurality of battery cell assemblies (120, 120'). The pack housing (110) can include a base plate (111), side walls (112, 113, 114, 115), and a center beam (116).

[0200] Here, two directions substantially parallel to the mounting surface of the base plate (111) (i.e., the surface facing the battery cell assembly (120)) are defined as the X direction and the Y direction, and a direction substantially perpendicular to the mounting surface of the base plate (111) is defined as the Z direction. The X direction, the Y direction, and the Z direction may be substantially perpendicular to each other.

[0201] Each of the base plate (111) and the side walls (112, 113) may be provided by an extrusion process. The extrusion direction of each of the base plate (111) and the side walls (112, 113) may be the X direction. That is, the YZ cross-section of each of the base plate (111) and the side walls (112, 113) may be constant depending on the position in the X direction except for deformation due to additional tooling. Here, the YZ cross-section may be substantially parallel to the Y direction and the Z direction, and substantially perpendicular to the X direction. The base plate (111) and the side walls (112, 113) may be arranged in the Y direction. The side walls (114, 115) may also be provided by an extrusion process.

[0202] According to exemplary embodiments, the base plate (111) and side walls (112, 113) may be joined by friction stir welding. The base plate (111) may include a plurality of unit plates joined by friction stir welding.

[0203] The center beam (116) may extend in the X direction. The center beam (116) may be interposed between the side walls (112, 113). The center beam (116) may be included in a center plate, which is one of a plurality of unit plates that are friction stir welded to each other. Accordingly, the center beam (116) may be formed together with the center plate, and the center beam (116) may be a continuous element integrally formed with the center plate.

[0204] The base plate (111) may include a plurality of cooling channels. The plurality of cooling channels may provide passages for the movement of a coolant, such as water, for example. The plurality of cooling channels may be formed by an extrusion process. The plurality of cooling channels may extend in the X direction. The plurality of cooling channels may be spaced apart in the Y direction.

[0205] A plurality of battery cell assemblies (120, 120') may be on a base plate (111) of a pack housing (110). The base plate (111) may support the plurality of battery cell assemblies (120, 120'). Side walls (112, 113, 114, 115) may horizontally surround the plurality of battery cell assemblies (120, 120'). The side walls (112, 113, 114, 115) may protect the plurality of battery cell assemblies (120, 120').

[0206] The battery cell assembly (120) is substantially the same as that described with reference to FIGS. 25 and 26. Each of the battery cell assemblies (120') is identical to the battery cell assembly (120), but may include only normal battery cells (121'). That is, in the battery cell assemblies (120'), the battery cell (121) may be replaced with the battery cell (121'). The location of the battery cell assembly (120) may be determined according to the target internal short-circuit occurrence location scenario.

[0207] The center beam (116) and cross beams (131) can isolate the plurality of battery cell assemblies (120, 120') from each other. The plurality of battery cell assemblies (120, 120') can be spaced apart in the Y direction with the center beam (116) therebetween. The center beam (116) can be interposed between the plurality of battery cell assemblies (120, 120'). The plurality of battery cell assemblies (120, 120') can be spaced apart in the X direction with the cross beams (131) therebetween. The cross beams (131) can be interposed between the plurality of battery cell assemblies (120, 120').

[0208] In Fig. 27, the arrangement of the plurality of battery cell assemblies (120, 120') can be said to be a 3 * 2 arrangement. The arrangement of the plurality of battery cell assemblies (120, 120') disclosed in Fig. 27 is a non-limiting example and does not limit the technical idea of ​​the present invention in any sense. A person skilled in the art will be able to easily arrive at a plurality of battery cell assemblies (120, 120') arranged in M ​​* N (wherein, M and N are each integers greater than or equal to 2) based on the description herein.

[0209] The battery pack (100) may further include leads coupled to side walls (112, 113, 114, 115) of the pack housing (110). The leads may cover elements mounted inside the battery pack (100), such as a plurality of battery cell assemblies (120, 120') and electrical components. The leads may be secured to the pack housing (110) by mechanical fastening means, such as bolting.

[0210] The battery pack (100) may further include exhaust devices coupled to the side walls (114, 115). Either of the side walls (114, 115) may include exhaust holes connected to the exhaust devices. The exhaust devices may be configured to delay thermal propagation by releasing high-temperature gas within the battery pack (100) to the outside when a thermal runway event occurs in a plurality of battery cell assemblies (120, 120').

[0211] Here, thermal runaway of the plurality of battery cell assemblies (120, 120') is a state in which temperature changes of the plurality of battery cell assemblies (120, 120') further accelerate the temperature change, which is an uncontrollable positive feedback. The plurality of battery cell assemblies (120, 120') in a state of thermal runaway exhibit a rapid temperature increase and emit a large amount of high-pressure gas and combustion debris.

[0212] The battery pack (100) may further include a Battery Management System (BMS). The BMS may be configured to monitor, balance, and control the battery pack (100). Monitoring of the battery pack (100) may include measuring voltage and current of specific nodes within a plurality of battery cell assemblies (120, 120') and measuring temperature of set locations within the battery pack (100). The battery pack (100) may include measuring instruments for measuring the voltage, current, and temperature described above.

[0213] Balancing of the battery pack (100) is an operation to reduce the deviation between the plurality of battery cell assemblies (120, 120'). Control of the battery pack (100) includes preventing the occurrence of overcharge, overdischarge, and overcurrent. Through monitoring, balancing, and control, the battery pack (100) can operate under optimal conditions, thereby preventing shortening of the lifespan of each of the plurality of battery cell assemblies (120, 120').

[0214] The battery pack (100) may further include additional electrical components, such as a cooling device, a PRA (Power Relay Assembly), and a safety plug. The cooling device may include a cooling fan. The cooling fan may prevent overheating of each of the plurality of battery cell assemblies (120, 120') by circulating air inside the battery pack (100). The PRA may be configured to supply or cut off power from the high-voltage battery to an external load (e.g., a vehicle motor). The PRA may protect the plurality of battery cell assemblies (120, 120') and the external load (e.g., a vehicle motor) by cutting off power supply to the external load (e.g., a vehicle motor) in a situation where an abnormal voltage, such as a voltage surge, occurs. Additional electrical components may be interposed between the plurality of battery cell assemblies (120, 120') and the side wall (115). The space between the plurality of battery cell assemblies (120, 120') and the side wall (115) may be referred to as a component mounting area.

[0215] The battery pack (100) may further include a plurality of inter-busbars configured to electrically connect a plurality of battery cell assemblies (120, 120'). The plurality of battery cell assemblies (120, 120') may be connected in series by the plurality of inter-busbars. Accordingly, the battery pack (100) may be configured to output a high voltage to an external load (e.g., a motor of a vehicle).

[0216]

[0217] (Example 11)

[0218] FIG. 28 is a flowchart illustrating an internal short circuit test method according to exemplary embodiments.

[0219] Referring to FIG. 16 and FIGS. 23 to 28, a test item may be provided at P110. According to exemplary embodiments, the test item may include a variable resistance structure (VRS). The test item may be any one of the battery cell (121) of FIG. 23, the battery cell assembly (120) of FIG. 25, and the battery pack (100) of FIG. 27.

[0220] Next, at P120, the temperature of the test item can be raised above the transition temperature of the variable resistance film (VF). This can cause the test item to be in an internal short-circuit state, and an internal short-circuit test can be performed. An internal short-circuit refers to a state in which the positive and negative electrodes within the battery are in direct contact and electrically connected, which can result in severe thermal runaway, fire, or explosion.

[0221] During the internal short circuit test, temperature changes in the battery cells (121, 121'), voltage and current changes in the battery cells (121, 121'), physical changes in the battery cells (121, 121') such as expansion, contraction and leakage, and gas emission from the battery cells (121, 121') can be monitored.

[0222] Internal short-circuit test results can be used for safety assessments, design improvements, and regulatory compliance reporting. Internal short-circuit testing is a process designed to ensure the safety and reliability of battery cells (121, 121'). By assessing the response of battery cells (121, 121') under various scenarios and stress conditions, it can contribute to preventing potential risks to battery cells (121, 121').

[0223] A variable resistance structure (VRS) according to exemplary embodiments includes a transition metal oxide such as VO2, which can provide internal short-circuit test results with high reproducibility, precision, and accuracy, thereby improving the reliability of the internal short-circuit test and the reliability of a product designed based on the results of the internal short-circuit test.

[0224]

[0225] The present invention has been described in more detail through drawings and examples. However, the configurations described in the drawings or examples described in this specification are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

Claims

1. A positive electrode including a positive electrode current collector, a first positive electrode active material layer on the positive electrode current collector, and a second positive electrode active material layer spaced apart from the first positive electrode active material layer with the positive electrode current collector interposed therebetween; A negative electrode comprising a negative current collector, a first negative active material layer on the negative current collector, and a second negative active material layer spaced apart from the first negative active material layer with the negative current collector interposed therebetween; a separator between the anode and cathode; and It includes a variable resistance structure in contact with the positive electrode and the negative electrode, The above variable resistance structure includes a conductive foil and a variable resistance film on the conductive foil, and An electrode assembly characterized in that the variable resistance film comprises a transition metal oxide.

2. In paragraph 1, An electrode assembly characterized in that the variable resistance film comprises VO2.

3. In paragraph 1, An electrode assembly characterized in that the above variable resistance structure has a step shape.

4. In paragraph 1, The above positive electrode current collector includes a positive tab, and An electrode assembly characterized in that the variable resistance structure includes a first portion on the positive electrode tab and a second portion between the negative electrode and the separator.

5. In paragraph 4, An electrode assembly characterized in that the conductive foil is in contact with the positive electrode tab.

6. In paragraph 4, An electrode assembly characterized in that the conductive foil is bonded to the positive electrode tab by an adhesive.

7. In paragraph 4, An electrode assembly characterized in that the conductive foil is spaced apart from the second negative active material layer with the variable resistance film interposed therebetween.

8. In paragraph 4, An electrode assembly characterized in that the variable resistance film is in contact with the second negative electrode active material layer.

9. In paragraph 8, An electrode assembly characterized in that the variable resistance structure further includes an insulating layer interposed between the variable resistance film and the cathode.

10. In paragraph 4, An electrode assembly characterized in that the conductive foil is in contact with the second negative electrode active material layer.

11. In paragraph 4, An electrode assembly characterized in that the conductive foil is spaced apart from the positive electrode tab with the variable resistance film interposed therebetween.

12. In paragraph 4, An electrode assembly characterized in that the variable resistance film is in contact with the positive electrode tab.

13. In paragraph 1, The above negative electrode current collector includes a negative electrode tab, and An electrode assembly characterized in that the variable resistance structure includes a first portion on the cathode tab and a second portion between the cathode and the separator.

14. In paragraph 1, An electrode assembly characterized in that the variable resistance structure includes a first portion between the anode and the separator and a second portion between the cathode and the separator.

15. In paragraph 14, The above positive electrode current collector includes a positive electrode tab, The above negative current collector includes a negative tab, and An electrode assembly characterized in that the variable resistance structure is spaced apart from each of the positive and negative tabs.

16. In paragraph 14, An electrode assembly characterized in that the above variable resistance structure has a C shape.

17. A positive electrode including a positive electrode current collector, a first positive electrode active material layer on the positive electrode current collector, and a second positive electrode active material layer spaced apart from the first positive electrode active material layer with the positive electrode current collector interposed therebetween; A negative electrode comprising a negative current collector, a first negative active material layer on the negative current collector, and a second negative active material layer spaced apart from the first negative active material layer with the negative current collector interposed therebetween; a separator between the anode and cathode; and It includes a variable resistance structure in contact with the positive electrode and the negative electrode, The above variable resistance structure includes a conductive foil and a variable resistance film on the conductive foil, and An electrode assembly, characterized in that the first resistivity of the variable resistance film at the first temperature is at least twice the second resistivity at the second temperature higher than the first temperature.

18. In paragraph 17, The above first temperature is less than 341K, and An electrode assembly characterized in that the second temperature is greater than 341K.

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