Secondary battery

Abstract

The present invention relates to a secondary battery. The secondary battery comprises: an electrode assembly including an electrode; a case for accommodating the electrode assembly therein; an electrode lead connected to one side of the electrode assembly and including an end portion extending to the outside of the case; and a hollow conductive wire electrically connected to the end portion of the electrode lead and including an outer portion and an inner portion, wherein the outer portion includes a conductive material.

Description

secondary battery

[0001] It's about secondary batteries.

[0002] The recent rapid proliferation of battery-powered electronic devices, such as mobile phones, laptops, and electric vehicles, has led to a rapid increase in demand for high-energy density and high-capacity secondary batteries. Accordingly, active research and development is underway to improve the performance of secondary batteries. These secondary batteries include an electrode assembly comprising a positive and negative electrode, a case housing the electrode assembly, and electrode terminals connected to the electrode assembly.

[0003] One embodiment provides a lithium secondary battery exhibiting excellent heat dissipation effect.

[0004] According to the concept of the present invention, a secondary battery comprises: an electrode assembly including an electrode; a case accommodating the electrode assembly therein; an electrode lead connected to one side of the electrode assembly and including an end extending to the outside of the case; and a hollow conductor electrically connected to the end of the electrode lead and including an outer end and an inner end; wherein the outer end may include a conductive material.

[0005] According to another concept of the present invention, a secondary battery comprises: a first cell including a first electrode assembly, a first case accommodating the first electrode assembly therein, and a first electrode lead connected to at least one side of the first electrode assembly and extending to the outside of the first case; a second cell including a second electrode assembly, a second case accommodating the second electrode assembly therein, and a second electrode lead connected to at least one side of the second electrode assembly and extending to the outside of the second case; and a hollow conductor electrically connected to the first electrode lead and the second electrode lead, the hollow conductor including an outer portion and an inner portion; wherein the outer portion may include a conductive material.

[0006] A secondary battery according to one embodiment can exhibit excellent heat dissipation effect by evenly cooling each electrode plate substrate included in an electrode assembly.

[0007] A secondary battery according to an embodiment of the present invention may have excellent energy density by adopting a hollow conductor as a cooling means, so that a separate cooling means may not be required.

[0008] Figure 1 is a perspective view of a secondary battery according to an embodiment.

[0009] Figure 2 is a plan view of a secondary battery according to an embodiment.

[0010] Figure 3 is a plan view of an electrode assembly according to another embodiment.

[0011] Fig. 4 is a cross-sectional view of a hollow conductor according to an embodiment of the present invention, taken along line A-A' of Fig. 1.

[0012] FIG. 5 is a cross-sectional view of a hollow conductor according to another embodiment, taken along line A-A' of FIG. 1.

[0013] Figure 6 is a perspective view of a secondary battery according to another embodiment.

[0014] Figure 7 is a plan view of a secondary battery according to another embodiment.

[0015] Figure 8 is a perspective view of a secondary battery according to another embodiment.

[0016] Figure 9 is a plan view of a secondary battery according to another embodiment.

[0017] Figure 10 is a conceptual diagram illustrating a battery pack according to another implementation example.

[0018] To fully understand the structure and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and subject to various modifications. However, the description of these embodiments is provided solely to ensure a complete disclosure of the present invention and to fully inform those skilled in the art of the invention of the scope of the invention.

[0019] In this specification, when a component is referred to as being on another component, it means that it can be formed directly on the other component, or a third component may be interposed between them. Furthermore, in the drawings, the thicknesses of the components are exaggerated for the sake of clarity. Parts designated by the same reference numerals throughout the specification represent the same components.

[0020] Embodiments described herein will be described with reference to cross-sectional and / or plan views, which are ideal illustrations of the present invention. In the drawings, the thicknesses of films and regions are exaggerated for the purpose of effectively explaining the technical contents. Accordingly, the regions illustrated in the drawings have a schematic nature, and the shapes of the regions illustrated in the drawings are intended to illustrate specific shapes of regions of the device and are not intended to limit the scope of the invention. Although terms such as first, second, and third are used to describe various components in various embodiments of the present specification, these components should not be limited by such terms. These terms are used only to distinguish one component from another. The embodiments described and illustrated herein also include complementary embodiments thereof.

[0021] Unless otherwise specified herein, the singular may also include the plural. Furthermore, unless otherwise specified, "A or B" may mean "including A, including B, or including A and B." As used herein, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components.

[0022] As used herein, “combination thereof” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the components.

[0023] Unless otherwise defined herein, the particle size may be the average particle size. In addition, the particle size refers to the average particle size (D50), which means the diameter of particles with a cumulative volume of 50% by volume in a particle size distribution. The average particle size (D50) can be measured by a method well known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope (TEM) photograph or a scanning electron microscope (SEM) photograph. Alternatively, the average particle size (D50) value can be obtained by measuring with a measuring device that utilizes dynamic light-scattering, performing data analysis to count the number of particles for each particle size range, and calculating from the counted number. Alternatively, the average particle size (D50) value can be obtained by measuring with a laser diffraction method. When measuring by laser diffraction, more specifically, after the particles to be measured are dispersed in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasonic waves of approximately 28 kHz at an output of 60 W, and the average particle size (D50) based on 50% of the particle size distribution in the measuring device can be calculated.

[0024]

[0025] FIG. 1 is a perspective view showing a secondary battery (1000) according to an embodiment of the present invention, and FIG. 2 is a plan view of a secondary battery (1000) according to an embodiment of the present invention.

[0026] Referring to FIGS. 1 and 2, a secondary battery according to one embodiment includes an electrode assembly (100) including an electrode (110), a case (200) accommodating the electrode assembly (100) therein, an electrode lead (300) connected to one side of the electrode assembly (100), the electrode lead (300) including an end (310) extending to the outside of the case (200), and a hollow conductor (400) electrically connected to the end (310) of the electrode lead (300), and including an outer portion (410) and an inner portion (420).

[0027]

[0028] Electrode assembly (100)

[0029] A secondary battery (1000) of one embodiment may include an electrode assembly (100) including an electrode (110). The electrode (110) of one embodiment may include a positive electrode (110a) and a negative electrode (110b). The electrode assembly (100) according to one embodiment may include a positive electrode (110a), a negative electrode (110b) facing the positive electrode (110a), and a separator (not shown) disposed between the positive electrode (110a) and the negative electrode (110b). However, the present invention is not limited thereto, and the electrode assembly (100) may further include an additional functional layer, such as an adhesion enhancing layer, disposed between the positive electrode (110a) and the separator (not shown) or between the negative electrode (110b) and the separator (not shown).

[0030] An electrode assembly (100) according to another embodiment may include an anode (110a), a cathode (110b) facing the anode (110a), and a solid electrolyte layer (not shown) disposed between the anode (110a) and the cathode (110b). However, the present invention is not limited thereto, and the electrode assembly (100) may further include an additional functional layer, such as an adhesion enhancing layer, disposed between the anode (110a) and the solid electrolyte layer (not shown) or between the cathode (110b) and the solid electrolyte layer (not shown).

[0031] The positive electrode (110a) of one embodiment may include a positive electrode current collector and a positive electrode active material layer disposed on the positive electrode current collector. The positive electrode active material layer may include a positive electrode active material, a solid electrolyte, a conductive material, and a binder.

[0032] The cathode current collector may provide a reference surface on which the cathode active material layer is disposed. The cathode current collector may include, for example, a plate or foil comprising indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof.

[0033] In one embodiment, the positive electrode (110a) may omit the positive electrode current collector. In order to increase the bonding strength between the positive electrode current collector and the positive electrode active material layer, a carbon layer having a thickness of 0.1 μm to 4 μm may be additionally disposed between the positive electrode current collector and the positive electrode active material layer.

[0034] A cathode active material is a material that can reversibly absorb and desorb lithium ions. The cathode active material may include, but is not necessarily limited to, lithium transition metal oxides such as lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganate, and lithium iron phosphate, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, or vanadium oxide. The cathode active materials may be used alone or as a mixture of two or more.

[0035] Lithium transition metal oxides include, for example, Li a A 1-b B b D2(0.90≤a≤1, 0≤b≤0.5), Lia HAVE BEEN 1-b B b O 2-c D c (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05), LiE 2-b B b O 4-c D c (0≤b≤0.5, 0≤c≤0.05), Li a Ni 1-b-c Co b B c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Co b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Mr b B c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2), Li a Ni 1-b-c Mr b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni b HAVE BEEN c G d O2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1), Li a Ni b Co c Mr d GeO2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0.001≤e≤0.1), Li a NiGbO2(0.9≤a≤1, 0.001≤b≤0.1), Li a CoGbO2(0.90≤a≤1, 0.001≤b≤0.1), Li aMnGbO2(0.90≤a≤1, 0.001≤b≤0.1), Li a Mn2GbO4(0.90≤a≤1, 0.001≤b≤0.1), QO2, QS2, LiQS2, V2O5, LiV2O5, LiIO2, LiNiVO4, Li 3-f J2(PO4)3(0≤f≤2), Li 3-f A compound represented by any one of Fe2(PO4)3(0≤f≤2), LiFePO4. In these compounds, a capital letter “” represents Ni, Co, Mn, or a combination thereof, a capital letter “” represents Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof, a capital letter “” represents O, F, S, P, or a combination thereof, a capital letter “” represents Co, Mn, or a combination thereof, a capital letter “” represents F, S, P, or a combination thereof, a capital letter “” represents Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof, a capital letter “” represents Ti, Mo, Mn, or a combination thereof, a capital letter “” represents Cr, V, Fe, Sc, Y, or a combination thereof, and a capital letter “” represents V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0036] The cathode active material may include, for example, a lithium salt of a transition metal oxide having a layered rock salt type structure among the lithium transition metal oxides described above. The "layered rock salt type structure" is, for example, a cubic rock salt type structure. <111> It is a structure in which oxygen atomic layers and metal atomic layers are alternately and regularly arranged in a direction, and thereby each atomic layer forms a two-dimensional plane. The "cubic rock salt structure" refers to the sodium chloride type (NaCl type) structure, which is a type of crystal structure, and specifically refers to a structure in which the face-centered cubic lattice (fcc) formed by each cation and anion is arranged with a displacement of half of the ridge of the unit lattice. Lithium transition metal oxides having this layered rock salt structure include, for example, LiNi x Co y Al z O2(NCA) or LiNi x Co y Mn z O2(NCM) (0 <x<1,0<y<1, 0<z<1, x+y+z=1) 등의 삼원계 리튬전이금속산화물일 수 있다. 양극활물질이 층상암염형 구조를 갖는 삼원계 리튬전이금속산화물을 포함하는 경우, 이차 전지의 에너지 밀도가 커지고 열안정성이 향상될 수 있다.

[0037] The above-described compound included in the positive electrode active material may be covered by a coating layer (not shown). The positive electrode active material may also be a mixture of the above-described compound and a compound to which a coating layer is added. Meanwhile, the coating layer added to the surface of the positive electrode active material may include, for example, an oxide, a hydroxide, an oxyhydroxide, an oxycarbonate, or a hydroxycarbonate of the coating elements below. The compound forming the coating layer may be amorphous or crystalline. The coating elements included in the coating layer may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof. The coating layer may include, for example, Li2O-ZrO2 (LZO). The method of forming the coating layer is selected within a range that does not adversely affect the physical properties of the positive electrode active material. The method of forming the coating layer includes, for example, spray coating, dipping, etc.

[0038] When the cathode active material is a ternary lithium transition metal oxide such as NCA or NCM and contains nickel (Ni), the capacity density of the secondary battery can be increased, thereby reducing metal dissolution of the cathode active material in a charged state. As a result, the cycle characteristics of the secondary battery in a charged state are improved. Meanwhile, the “cycle characteristics” are characteristics indicating the degree to which the secondary battery is deteriorated due to charge / discharge of the secondary battery. A secondary battery with high cycle characteristics may be deteriorated less due to charge / discharge, and a secondary battery with low cycle characteristics may be deteriorated more due to charge / discharge.

[0039] The shape of the cathode active material may include particle shapes such as a sphere or an ellipsoid, for example. The particle size and content of the cathode active material are not particularly limited.

[0040] An electrode assembly (100) according to one embodiment may include a positive electrode (110a), a negative electrode (110b) facing the positive electrode (110a), and a separator (not shown) disposed between the positive electrode (110a) and the negative electrode (110b). The separator may be a multilayer film of polyethylene, polypropylene, polyvinylidene fluoride, or two or more layers thereof, and a mixed multilayer film such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, or a polypropylene / polyethylene / polypropylene three-layer separator may be used.

[0041] The separator may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof, positioned on one or both sides of the porous substrate.

[0042] The porous substrate may be a polymer film formed of any one polymer selected from polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyamide, polyimide, polycarbonate, polyether ketone, polyarylether ketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylene sulfide, polyethylene naphthalate, glass fiber, Teflon, and polytetrafluoroethylene, or a copolymer or mixture of two or more thereof. The organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic polymer. The above inorganic material may include inorganic particles selected from, but not limited to, Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0043] 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.

[0044] An electrode assembly (100) according to one embodiment may include a positive electrode (110a), a negative electrode (110b) facing the positive electrode (110a), and a solid electrolyte layer (not shown) disposed between the positive electrode (110a) and the negative electrode (110b). When the electrode assembly (100) includes a solid electrolyte layer, the positive electrode active material layer according to one embodiment may include a solid electrolyte. The solid electrolyte included in the positive electrode active material layer may include a sulfide-based solid electrolyte having excellent lithium ion conductivity characteristics. Sulfide-based solid electrolytes include, for example, Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-ZmSn (m, n are positive numbers, capital letter “” is one of Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are positive numbers, capital letter “” is one of P, Si, Ge, B, Al, Ga In), Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x It may include at least one selected from Ix(0≤x≤2).

[0045] Sulfide-based solid electrolytes include, for example, Li 7-x PS 6-x Cl x(0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I x It may be an argyrodite-type compound including at least one selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0046] Alternatively, the sulfide-based solid electrolyte is Li 7-a M a PS 6-c X c It may be an argyrodite-type compound containing (0≤a≤2, (0≤c≤2)), where X may be F, Br, Cl, or a combination thereof. M is candium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof. Can be.

[0047] The density of the argyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. Since the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state battery is reduced, and the defect of the solid electrolyte membrane being penetrated and short-circuited due to the formation of lithium dendrites can be prevented. The elastic modulus of the solid electrolyte may be, for example, 15 GPa to 35 GPa.

[0048] The solid electrolyte included in the positive electrode active material layer may have a median particle size (D50) smaller than the solid electrolyte included in the solid electrolyte layer described later. For example, the median particle size (D50) of the solid electrolyte included in the positive electrode active material layer may be 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, or 20% or less of the median particle size (D50) of the solid electrolyte included in the solid electrolyte layer. Meanwhile, the median particle size (D50) may be a median diameter measured using a laser particle size distribution meter.

[0049] The cathode active material layer may include a conductive material. The conductive material may be conductive without causing chemical changes in the secondary battery, thereby enhancing the conductivity of the cathode active material and the solid electrolyte. The conductive material may include a carbon-based material. For example, the conductive material may include one or more selected from graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0050] The positive electrode active material layer may further include a binder. The binder may include a material for binding the positive electrode active material, solid electrolyte, and conductive material included in the positive electrode active material layer, and improving bonding strength with the positive electrode current collector. The binder may include, for example, polyvinylidene fluoride, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0051] Based on 100 parts by weight of the total of the positive electrode active material, solid electrolyte, conductive material, and binder, the positive electrode active material layer may include 85 parts by weight or more and 92 parts by weight or less of the positive electrode active material. Based on 100 parts by weight of the total of the positive electrode active material, solid electrolyte, conductive material, and binder, the positive electrode active material layer may include 0.5 parts by weight or more and 1.5 parts by weight or less of the binder.

[0052] Based on 100 parts by weight of the solid electrolyte, the positive electrode active material layer may contain 1 part by weight or more and 50 parts by weight or less of a conductive material. If the conductive material is included in the positive electrode active material layer in an amount less than 1 part by weight based on 100 parts by weight of the solid electrolyte, the proportion of the conductive material may decrease, which may lower the electrical conductivity of the positive electrode active material layer. If the conductive material is included in the positive electrode active material layer in an amount greater than 50 parts by weight based on 100 parts by weight of the solid electrolyte, the proportion of the conductive material may be excessively high, which may prevent a coating layer covering the surface of the solid electrolyte from being properly formed.

[0053] The cathode active material layer may further include additives such as fillers, coating agents, dispersants, and ion conductive aids in addition to the above-described cathode active material, solid electrolyte, conductive agent, and binder.

[0054] In one embodiment, the solid electrolyte layer is positioned between the positive and negative electrodes and includes a sulfide-based solid electrolyte with excellent lithium ion conductivity characteristics. The solid electrolyte included in the solid electrolyte layer may be the same as or different from any of the materials that may be included in the solid electrolyte included in the aforementioned positive electrode active material layer.

[0055] In one embodiment, the solid electrolyte layer may include a sulfide-based solid electrolyte. The sulfide-based solid electrolyte may be manufactured by treating starting materials such as Li2S and P2S5 by a melting rapid cooling method or a mechanical milling method. In addition, a heat treatment may be performed after the treatment. The solid electrolyte may be amorphous, crystalline, or a mixture thereof. In addition, the solid electrolyte may include, for example, at least sulfur (S), phosphorus (P), and lithium (Li) as constituent elements among the above-described sulfide-based solid electrolyte materials. For example, the solid electrolyte may be a material including Li2S-P2S5. When using a sulfide-based solid electrolyte material including Li2S-P2S5 to form the solid electrolyte, the mixing molar ratio of Li2S and P2S5 is, for example, in the range of Li2S:P2S5=50:50 to 90:10.

[0056] Sulfide-based solid electrolytes include, for example, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I x It may be an argyrodite-type compound including at least one selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0057] Alternatively, the sulfide-based solid electrolyte is Li 7-a M a PS 6-c X c It may be an argyrodite-type compound containing (0≤a≤2, (0≤c≤2)), where X may be F, Br, Cl, or a combination thereof. M is candium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof. Can be.

[0058] The density of the argyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. When the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state battery is reduced, and the defect of the solid electrolyte membrane being penetrated and short-circuited due to the formation of lithium dendrites can be prevented. The elastic modulus of the solid electrolyte is, for example, 15 GPa to 35 GPa.

[0059] The solid electrolyte layer may further include a binder. The binder included in the solid electrolyte layer may include, but is not limited to, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, and the like. The binder of the solid electrolyte layer may be the same as or different from the binder included in the positive electrode active material layer or the binder included in the negative electrode active material layer.

[0060] The negative electrode (110b) of one embodiment may include a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector. The negative electrode active material layer may include a negative electrode active material and a binder.

[0061] The negative electrode current collector can provide a reference surface on which the negative electrode active material layer is arranged. The negative electrode current collector can include, for example, a material that does not react with lithium, i.e., does not form an alloy or compound with lithium. Materials constituting the negative electrode current collector include, but are not limited to, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni), and any material that can be used as an electrode current collector can be used. The thickness of the negative electrode current collector can be 1 to 20 μm, for example, 5 to 15 μm, or for example, 7 to 10 μm.

[0062] The negative electrode current collector may be composed of one of the above-described metals, or may include an alloy or coating material of two or more metals. The negative electrode current collector may be, for example, in the form of a plate or foil. Meanwhile, in one embodiment, the negative electrode current collector may be omitted.

[0063] The negative electrode active material included in the negative electrode active material layer may have a particle form. The median particle size average particle diameter (D50) of the negative electrode active material having a particle form may be, for example, 4 μm or less, 2 μm or less, 1 μm or less, or 900 nm or less. The median particle size average particle diameter (D50) of the negative electrode active material may be, for example, 10 nm to 4 μm, 10 nm to 2 μm, or 10 nm to 900 nm. When the negative electrode active material has a median particle size average diameter (D50) within this range, reversible absorption and / or desorption of lithium may be facilitated during charge and discharge. Meanwhile, the median particle size average diameter (D50) may be a median diameter measured using a laser particle size distribution meter.

[0064] The negative electrode active material may include, for example, at least one selected from a carbon-based negative electrode active material and a metal or metalloid negative electrode active material.

[0065] The carbon-based negative electrode active material may be amorphous carbon, in particular. Examples of amorphous carbon include, but are not limited to, carbon black (CB), acetylene black (AB), furnace black (FB), ketjen black (KB), and graphene. Amorphous carbon is carbon that has no crystallinity or very low crystallinity, and is distinguished from crystalline carbon or graphitic carbon.

[0066] The metal or metalloid negative electrode active material includes, but is not necessarily limited to, one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn), and may be a metal negative electrode active material or a metalloid negative electrode active material that forms an alloy or compound with lithium. On the other hand, nickel (Ni) does not form an alloy with lithium and therefore is not a metal negative electrode active material.

[0067] The negative electrode active material layer may include one type of negative electrode active material among these negative electrode active materials, or may include a mixture of multiple different negative electrode active materials. For example, the negative electrode active material layer may include only amorphous carbon, or may include one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn).

[0068] In one embodiment, the negative electrode active material layer may include a mixture of amorphous carbon and one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The mixing ratio of the mixture of amorphous carbon and gold (Au) or the like may be, for example, a weight ratio of 10:1 to 1:2, 5:1 to 1:1, or 4:1 to 2:1, but is not necessarily limited to this range and may be selected depending on the characteristics of the secondary battery required. When the negative electrode active material has such a composition, the cycle characteristics of the secondary battery can be further improved.

[0069] The binder included in the negative electrode active material layer includes, but is not necessarily limited to, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, and the like. The binder may include a single binder or a plurality of different binders.

[0070] Since the negative electrode active material layer includes a binder, the negative electrode active material layer can be stably formed on the negative electrode current collector. That is, the bonding strength between the negative electrode active material layer and the negative electrode current collector can be increased. In addition, cracking of the negative electrode active material layer is suppressed despite changes in the volume and / or relative positions of the negative electrode active material layer during the charge and discharge process. If the negative electrode active material layer does not include a binder, the negative electrode active material layer can be easily separated from the negative electrode current collector. When the negative electrode active material layer is separated from the negative electrode current collector, the negative electrode current collector can come into contact with the solid electrolyte layer at the exposed portion of the negative electrode current collector, thereby increasing the possibility of a short circuit occurring.

[0071] The negative electrode active material layer is manufactured, for example, by dispersing a mixture of materials constituting the negative electrode active material layer onto a negative electrode current collector. Since the materials constituting the negative electrode active material layer include a binder, stable dispersion of the negative electrode active material within the mixture is possible. For example, when applying the mixture onto a negative electrode current collector using a screen printing method, the binder can prevent screen clogging (e.g., clogging by aggregates of the negative electrode active material).

[0072] In addition to the negative electrode active material and binder, the negative electrode active material layer may further include other additives. For example, the negative electrode active material layer may further include fillers, coating agents, dispersants, ion conductive additives, etc.

[0073] Meanwhile, although not shown, a carbon layer may be further included to improve adhesion between the negative electrode active material layer and the solid electrolyte layer.

[0074] The negative electrode of one embodiment may not include the negative electrode active material layer described above. For example, the negative electrode may include a negative electrode current collector and a negative electrode coating layer on the negative electrode current collector. The negative electrode current collector may provide a reference surface on which the negative electrode coating layer is disposed. The negative electrode current collector may include, for example, a material that does not react with lithium, i.e., does not form both an alloy and a compound with lithium. For example, the negative electrode current collector may include at least one metal selected from the group consisting of copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni). The thickness of the negative electrode current collector may be 1 μm to 20 μm, more specifically 5 μm to 15 μm, and more specifically 7 μm to 10 μm.

[0075] The negative electrode current collector may be composed of one of the above-described metals, or may include an alloy or coating material of two or more metals. The negative electrode current collector may have, for example, a plate or foil shape. Meanwhile, in one embodiment, the negative electrode current collector may be omitted.

[0076] The cathode coating layer can enable lithium metal to grow between the cathode current collector and the secondary battery during charging. The cathode coating layer can act as a protective layer for the lithium metal and simultaneously suppress the precipitation and growth of lithium dendrites.

[0077] The cathode coating layer may include a metal and carbon. For example, the cathode coating layer may include at least one metal selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The cathode coating layer may include at least one carbon selected from the group consisting of carbon black, acetylene black, furnace black, ketjen black, and graphene. In one embodiment, the cathode coating layer may include a mixture of carbon black and silver (Ag).

[0078] The cathode coating layer may further include additives other than metal and carbon. For example, the cathode coating layer may further include at least one additive selected from the group consisting of a binder, a filler, a coating agent, a dispersant, and an ion-conducting aid.

[0079] Meanwhile, although not shown, a carbon layer may be further included to improve adhesion between the cathode coating layer and the solid electrolyte layer.

[0080] Referring to FIG. 3, an electrode assembly (100') of another embodiment may include a unit cell (120) in which a first cathode (120a), a first solid electrolyte layer (120b), an anode (120c), a second solid electrolyte layer (120d), and a second cathode (120e) are sequentially arranged. Although not shown, an electrode assembly of another embodiment may include a unit cell in which a first cathode, a first solid electrolyte layer, a cathode, a second solid electrolyte layer, and a first cathode are sequentially arranged. The above-described contents regarding cathodes may be applied to each of the first cathode (120a) and the second cathode (120e). The above-described contents regarding solid electrolyte layers may be applied to each of the first solid electrolyte layer (120b) and the second solid electrolyte layer (120c). The above-described anodes may each be applied to the first anode (not shown) and the second anode (not shown). Hereinafter, detailed descriptions of overlapping technical features are omitted.

[0081] Referring to FIG. 3, an electrode assembly (100') of one embodiment may have a plurality of unit cells (120) stacked. An electrode assembly (100') of one embodiment may include an elastic sheet (130) between a first cathode (120a) and a second cathode (120e) of adjacent unit cells (120). An electrode assembly (100') of one embodiment may include an elastic sheet (130) in the outermost layer of a plurality of unit cells (120). Although not shown, an electrode assembly of another embodiment may have a plurality of unit cells stacked and include an elastic sheet between a first cathode and a second cathode of an adjacent unit cell.

[0082] The elastic sheet (130) may include, but is not limited to, at least one of polyurethane, natural rubber, spandex, isobutylene isoprene rubber (IIR), fluoroelastomer, elastomer, ethylene-propylene rubber (EPR), styrene-butadiene rubber (SBR), chloroprene, elastomer, rubber epichlorohydrin, nylon, terpene, isoprene rubber, polybutadiene, nitrile rubber, thermoplastic elastomer, silicone rubber, ethylene-propylene-diene rubber (EPDM), ethylene vinyl acetate (EVA), halogenated butyl rubber, neoprene, and copolymers thereof, for example, and any material having elasticity may be used without limitation. The elastic sheet of one embodiment may be made of a urethane-based material, for example, polyurethane.

[0083] The elastic sheet (130) may be pressurized so that the thickness upon installation is 40 to 90% of the initial thickness prior to applying pressure. For example, the elastic sheet (130) may be pressurized so that the thickness upon installation is 50 to 85% of the initial thickness prior to applying pressure, specifically 60 to 80%, or 65 to 75% of the initial thickness prior to applying pressure. Within the above range, the volume change of the negative electrode can be effectively absorbed, thereby enabling smooth charging and discharging of the secondary battery.

[0084] The elastic sheet (130) can effectively suppress changes in the volume of the negative electrode of a secondary battery including the above-described negative electrode coating layer.

[0085] The thickness of the elastic sheet (130) can be determined in the range of 200 to 500% of the thickness of the negative electrode coating layer formed when charging a secondary battery including a negative electrode coating layer. In a secondary battery including a negative electrode coating layer, the thickness of the negative electrode coating layer is determined in proportion to the current density of the positive electrode. That is, the thickness of the negative electrode coating layer is determined according to the amount of lithium moving from the positive electrode to the negative electrode, and thereby a change in the volume of the negative electrode occurs. Therefore, the thickness of the elastic sheet can be determined so as to absorb such a change in the volume of the negative electrode. Accordingly, by setting the thickness of the elastic sheet to the range of 200 to 500% of the thickness of the negative electrode coating layer formed when charging a secondary battery including a negative electrode coating layer, the change in the volume of the negative electrode can be effectively absorbed. For example, the thickness of the elastic sheet (130) can be in the range of 250 to 450% of the thickness of the negative electrode coating layer formed when charging a secondary battery including a negative electrode coating layer, specifically, for example, in the range of 300 to 400%.

[0086] The thickness of the elastic sheet (130) can be set in the range of, for example, 50 μm to 300 μm, and can be selectively set in some cases, for example, 100 μm to 150 μm, 200 μm to 300 μm, or 50 μm to 100 μm.

[0087] By including an elastic sheet between the negative electrode current collectors, the volume change of the negative electrode due to the lithium deposition reaction used in the negative electrode can be absorbed, thereby suppressing the volume change of the entire cell and obtaining a stable lifespan.

[0088] It goes without saying that the electrode assembly (100') described above in one embodiment can be applied to any electrode assembly of any embodiment described herein.

[0089]

[0090] Case (200)

[0091] A secondary battery of one embodiment may include a case (200) that houses an electrode assembly therein. The case (200) may be classified into a cylindrical shape, a square shape, a pouch shape, a coin shape, etc., depending on the shape of the secondary battery. The case (200) of one embodiment may have a cylindrical shape, a square shape, or a pouch shape.

[0092] A case (200) of one embodiment may be configured to house and seal an electrode assembly (100) therein. The case (200) may include a lower case that houses the electrode assembly (100) and an upper case that covers the electrode assembly (100) and is coupled to the lower case.

[0093] The lower case may include a receiving portion, which is a home for receiving an electrode assembly, and a sealing portion formed on the outer surface of the lower case to seal the outer surface of the lower case and the outer surface of the upper case. The sealing portion may secure an electrode lead, which will be described later, to the case.

[0094] In one embodiment, the case may include a flexible material.

[0095] In one embodiment, the case may be formed as a multilayer structure having a first insulating layer, a metal layer, and a second insulating layer.

[0096] The first insulating layer may be formed on the inner surface of the case and may be formed of a material having insulating and heat-sealing properties. The first insulating layer is formed on the first surface of the metal layer and forms the inner surface of the case facing the electrode assembly. The first insulating layer may be formed of any one selected from cast polypropylene (CPP) and its equivalents that do not react with electrolytes, but is not necessarily limited thereto. When the electrode assembly is accommodated in the receiving portion of the lower case and covered with the upper case, the first insulating layers come into contact with each other. Therefore, when the sealing portion of the case is heat-sealed, the first insulating layers are adhered to each other and the case is sealed.

[0097] The metal layer is interposed between the first and second insulating layers and serves to prevent moisture and oxygen from entering from the outside. Additionally, the metal layer maintains the mechanical strength of the case. The metal layer may be formed of, but is not necessarily limited to, aluminum, stainless steel, copper, or equivalents.

[0098] The second insulating layer is the outer surface of the case and serves to mitigate mechanical and chemical impacts from external electronic devices. The second insulating layer is formed on the second surface of the metal layer and constitutes the outer surface of the case. The second insulating layer may be formed of any one selected from nylon, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), and equivalents thereof, but is not necessarily limited thereto.

[0099]

[0100] Electrode lead (300)

[0101] Referring to FIGS. 1 and 2, a secondary battery (1000) of one embodiment may include an electrode lead (300) connected to one side of an electrode assembly (100). A secondary battery (1000) of one embodiment may include an electrode lead (300) connected to both sides of an electrode assembly (100).

[0102] Referring to FIG. 2, an electrode lead (300) of one embodiment may include an end (310) extending to the outside of the case. The electrode lead (300) may be connected to the electrode assembly (100) and may extend to the outside of the case (200) to electrically connect the electrode assembly (100) to the outside.

[0103] Referring to FIG. 2, an electrode lead (300) of one embodiment may extend in a second direction (D2). The second direction (D2) may be a direction substantially perpendicular to a first direction (D1) in which a hollow conductor (400) described later extends.

[0104] Referring to FIG. 2, an electrode lead (300) of one embodiment may include a positive electrode lead (300a) connected to a positive electrode (110a), and a negative electrode lead (300b) connected to a negative electrode (110b). The positive electrode lead (300a) may be connected to one side of the electrode assembly (100), and the negative electrode lead (300b) may be connected to the other side of the electrode assembly (100).

[0105] Referring to FIG. 2, a secondary battery (1000) of one embodiment may include a positive electrode tab (PT) electrically connecting a positive electrode (110a) and a positive electrode lead (300a). A secondary battery (1000) of one embodiment may include a negative electrode tab (NT) electrically connecting a negative electrode (110b) and a negative electrode lead (300b).

[0106]

[0107] Hollow wire (400)

[0108] Referring to FIGS. 1 and 2, a secondary battery (1000) of one embodiment may include a hollow conductor (400) electrically connected to an end (310) of an electrode lead (300). Referring to FIGS. 4 and 5, the hollow conductor (400) of one embodiment may include an outer portion (410) and an inner portion (420).

[0109] Referring to FIGS. 4 and 5, the outer portion (410) of the hollow conductive wire (400) of one embodiment may include a conductive material. The conductive material of one embodiment may be, but is not limited to, gold (Au), silver (Ag), copper (Cu), lead (Pb), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), nickel (Ni), or an alloy thereof, and any material having electrical conductivity may be used as the conductive material. In this case, the hollow conductive wire (400) may be electrically connected to the electrode lead (300). The hollow conductive wire (400) of one embodiment may include an anode conductive wire (400a) electrically connected to an anode lead (300a) and a cathode conductive wire (400b) electrically connected to an anode lead (300b).

[0110] The conductive material of one embodiment may include a material with high thermal conductivity. For example, the conductive material may be, but is not limited to, gold (Au), silver (Ag), copper (Cu), aluminum (Al), or an alloy thereof, and any material with high thermal conductivity may be used as the conductive material. Heat generated in the electrode assembly (100) may be transferred to the electrode lead (300). The heat received by the electrode lead (300) may be transferred to a hollow conductor (400) including a conductive material with high thermal conductivity.

[0111] Referring to FIGS. 4 and 5, the inner portion (420) of the hollow conductor (400) of one embodiment may be configured to allow a refrigerant (RF) to flow. The hollow conductor (400) of one embodiment may cool the surroundings by allowing the refrigerant (RF) to flow through the inner portion (420).

[0112] The hollow conductor (400) is connected to the electrode tab through the electrode lead (300) and extends to the electrode plate. The electrode plate, the electrode tab, and the electrode lead (300) are made of a metal having high thermal conductivity. Heat generated from the individual electrode plates of the electrode assembly (100) is transferred to the hollow conductor (400) through the electrode tab and the electrode lead (300), respectively, and the hollow conductor (400) can cool the surroundings by flowing a coolant (RF) in the inner part (420). In the secondary battery of the present invention, the hollow conductor (400) is directly or indirectly connected to the individual electrode plates of the electrode assembly (100) through the electrode tab and the electrode lead (300) having high thermal conductivity, thereby providing an even heat dissipation effect to the individual electrode plates of the electrode assembly (100).

[0113] The above hollow conductor (400) is a conductor that electrically connects a plurality of electrode leads (300) and connects the electrode assembly (100) to an external power source, and the secondary battery of the present invention can evenly provide a heat dissipation effect to the individual electrode plates of the electrode assembly (100) without having a separate heat dissipation means.

[0114] In the case where the electrode assembly (100') including the elastic sheet (130) between the unit cells (120) illustrated in FIG. 3 is provided with a cooling means on one or both sides of the electrode assembly (100), the elastic sheet (130) acts as a thermal resistance, so that the heat dissipation efficiency of the unit cell (120) located at the center and the unit cell (120) located at the edge are different, and the more unit cells (120) are stacked, the lower the heat dissipation effect of the central unit cell (120). Even in this case where the secondary battery of the present invention includes the elastic sheet (130), it can provide a heat dissipation effect with little deviation to each unit cell (120) because it provides a heat dissipation effect for each individual electrode plate.

[0115] In one embodiment, the refrigerant (RF) may be a coolant, etc. In one embodiment, the refrigerant (RF) may be an insulated coolant. In one embodiment, the refrigerant (RF) may be an insulating oil or a special coolant (e.g., 3M's NOVEC, etc.). When an insulated coolant, insulating oil, or a special coolant is used as the refrigerant (RF), the hollow conductor (400) can be cooled without the risk of a short circuit, thereby cooling the electrode lead (300) and the electrode assembly (100).

[0116] Referring to FIG. 5, the hollow conductor (400) of another embodiment may further include a corrosion-resistant coating layer (430) disposed between the inner portion (420) and the outer portion (410). Insulating coolant, insulating oil, or special coolant can cool the hollow conductor (400) without a risk of short circuit because it is nonpolar and corrosion-resistant, but is expensive, thus increasing the manufacturing cost of the secondary battery (1000). The hollow conductor (400) according to one embodiment further includes a corrosion-resistant coating layer (430) disposed between the inner portion (420) and the outer portion (410), so that even when a low-cost general coolant that is not electrically insulated is applied, the hollow conductor (400) can be cooled to cool the electrode lead (300) and the electrode assembly (100). The above-mentioned corrosion-resistant coating layer (430) may be formed of a material that is substantially electrically insulating and has high thermal conductivity. For example, aluminum nitride (AlN), boron nitride (BN), etc. may be used, but the present invention is not necessarily limited thereto.

[0117] Although not shown, the hollow conductor (400) of one embodiment may further include a covering layer (not shown) disposed on the outer surface of the outer portion (410). The covering layer (not shown) may be electrically insulated to prevent the hollow conductor (400) from contacting external materials or other conductors. The covering layer (not shown) may protect the hollow conductor (400) from physical impact, pressure, and mechanical damage. The covering layer (not shown) may prevent the hollow conductor (400) from damage caused by external factors such as water, moisture, chemicals, and contaminants.

[0118] Referring to FIGS. 6 and 7, the hollow conductor (400) of one embodiment may extend in a first direction (D1). The first direction (D1) may be a direction substantially perpendicular to the second direction (D2), which is the direction in which the electrode lead (300) described above extends.

[0119] Referring to FIGS. 6 and 7, one anode conductor (400a) can be connected to multiple anode leads (300a) to electrically connect the anodes (110a) of multiple electrode assemblies (100).

[0120] Referring to FIGS. 6 and 7, one cathode conductor (400b) can be connected to a plurality of cathode leads (300b) to electrically connect the cathodes (110b) of a plurality of electrode assemblies (100).

[0121]

[0122] Referring to FIGS. 8 and 9, a secondary battery (2000) according to another embodiment includes a first cell (1001) including a first electrode assembly (101), a first case (201) accommodating the first electrode assembly (101) therein, and a first electrode lead (301) connected to at least one side of the first electrode assembly (101) and extending to the outside of the first case (201); a second cell (1002) including a second electrode assembly (102), a second case (202) accommodating the second electrode assembly (102) therein, and a second electrode lead (302) connected to at least one side of the second electrode assembly (102) and extending to the outside of the second case (202); And it may include a hollow conductor (400) electrically connected to the first electrode lead (301) and the second electrode lead (302), and including an outer portion (410) and an inner portion (420). The outer portion (410) may include a conductive material. The above-described contents may be applied to each configuration. Hereinafter, detailed descriptions of overlapping technical features are omitted.

[0123] In one embodiment, the first cell (1001) and the second cell (1002) may have the same or different configurations.

[0124] Referring to FIGS. 8 and 9, the first cell (1001) and the second cell (1002) can be arranged in the second direction (D2). Referring to FIG. 9, the first cell (1001) and the second cell (1002) can be arranged symmetrically with the hollow conductor (400) as the reference axis.

[0125] Referring to FIGS. 8 and 9, the first electrode lead (301) may include a first positive electrode lead (301a) and a first negative electrode lead (301b).

[0126] Referring to FIGS. 8 and 9, the second electrode lead (302) may include a second positive electrode lead (302a) and a second negative electrode lead (302b).

[0127] Referring to FIGS. 8 and 9, the first cell (1001) and the second cell (1002) may be arranged symmetrically with the anode conductor (400a) as a reference axis. In this case, the first anode lead (301a) and the second anode lead (302a) may be arranged adjacent to each other. The anode conductor (400a) may be electrically connected to the first anode lead (301a) and the second anode lead (302a). In one embodiment, the first anode lead (301a) and the second anode lead (302a) may be indirectly electrically connected through the anode conductor (400a). In one embodiment, the first anode lead (301a) and the second anode lead (302a) may be electrically connected by directly contacting each other.

[0128] Referring to FIGS. 8 and 9, the first cell (1001) and the second cell (1002) may be arranged symmetrically with the negative electrode lead (400b) as a reference axis. In this case, the first negative electrode lead (301b) and the second negative electrode lead (302b) may be arranged adjacent to each other. The negative electrode lead (400b) may be electrically connected to the first negative electrode lead (301b) and the second negative electrode lead (302b). In one embodiment, the first negative electrode lead (301b) and the second negative electrode lead (302b) may be indirectly electrically connected through the negative electrode lead (400b). In one embodiment, the first negative electrode lead (301b) and the second negative electrode lead (302b) may be electrically connected by directly contacting each other.

[0129] Referring to FIGS. 8 and 9, the first cell (1001) and the second cell (1002) can be arranged in the order of first negative electrode lead (301a) / first case (201) / first positive electrode lead (301a) / second positive electrode lead (302a) / second case (202) / second negative electrode lead (302b) in the second direction (D2).

[0130] Referring to FIGS. 8 and 9, the first cell (1001) may include a plurality of first cells (1001) aligned in a first direction (D1). The second cell (1002) may include a plurality of second cells (1002) aligned in the first direction (D1).

[0131]

[0132] Referring to FIG. 10, one embodiment may provide a battery pack (BP) including the first cell (1001) and the second cell (1002) described above. The battery pack (BP) may accommodate the first cell (1001) and the second cell (1002) therein. The battery pack (BP) may include a cooling means (F) connected to a positive conductor (400a). The battery pack (BP) may include a cooling means (F) connected to a negative conductor (400b). The battery pack (BP) may individually include the cooling means (F) connected to the positive conductor (400a) and the cooling means (F) connected to the negative conductor (400b). The battery pack (BP) may include a cooling means (F) connected to the positive conductor (400a) and the negative conductor (400b) simultaneously.

[0133] The above cooling means (F) may be connected to a hollow conductor (400) and configured to allow refrigerant to flow and exchange heat of the refrigerant.

[0134] For example, the cooling means (F) may include a heat exchanger and a pump.

[0135] The above heat exchanger may be configured to discharge heat of heated refrigerant supplied from the hollow conductor (400).

[0136] The above pump may be configured to discharge the cooled refrigerant from the heat exchanger into the hollow conductor (400).

[0137]

[0138] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the patent claims, the detailed description of the invention, and the attached drawings, and it is obvious that this also falls within the scope of the present invention.

Claims

1. An electrode assembly including an electrode; A case that houses the electrode assembly therein; An electrode lead connected to at least one side of the electrode assembly and including an end extending outside the case; and A hollow conductor electrically connected to the end of the electrode lead and including an outer side and an inner side; A secondary battery wherein the outer portion includes a conductive material.

2. In paragraph 1, A secondary battery in which the inner portion is configured to allow refrigerant to flow.

3. In paragraph 2, The above refrigerant comprises at least one of insulating coolant, insulating oil, and special coolant.

4. In paragraph 1, The above hollow conductor is a secondary battery extending in the first direction.

5. In paragraph 1, A secondary battery further comprising a corrosion-resistant coating layer disposed between the inner portion and the outer portion.

6. In paragraph 1, The above electrode includes an anode and a cathode, A secondary battery comprising a positive electrode lead connected to the positive electrode, and a negative electrode lead connected to the negative electrode.

7. In paragraph 6, an anode tab electrically connecting the anode and the anode lead to each other; and A secondary battery further comprising a negative tab electrically connecting the negative electrode and the negative electrode lead to each other.

8. In paragraph 6, The above hollow conductor, a positive conductor electrically connected to the positive lead; and A secondary battery comprising a negative electrode conductor electrically connected to the negative electrode lead.

9. In paragraph 1, The above electrode assembly, A unit cell in which a first cathode, a first solid electrolyte layer, an anode, a second solid electrolyte layer, and a second cathode are sequentially arranged; and A secondary battery in which a plurality of the above unit cells are stacked and an elastic sheet is included between the first negative electrode and the second negative electrode of adjacent unit cells.

10. In paragraph 1, A secondary battery further comprising a cooling means connected to the hollow conductor and configured to allow a refrigerant to flow and exchange heat of the refrigerant.

11. A first cell including a first electrode assembly, a first case accommodating the first electrode assembly therein, and a first electrode lead connected to at least one side of the first electrode assembly and extending to the outside of the first case; A second cell comprising a second electrode assembly, a second case housing the second electrode assembly therein, and a second electrode lead connected to at least one side of the second electrode assembly and extending to the outside of the second case; and A hollow conductor electrically connected to the first electrode lead and the second electrode lead, the hollow conductor including an outer portion and an inner portion; A secondary battery wherein the outer portion includes a conductive material.

12. In paragraph 11, A secondary battery in which the inner portion is configured to allow refrigerant to flow.

13. In paragraph 12, The above refrigerant comprises at least one of insulating coolant, insulating oil, and special coolant.

14. In paragraph 11, The above hollow conductor is a secondary battery extending in the first direction.

15. In paragraph 11, A secondary battery further comprising a corrosion-resistant coating layer disposed between the inner portion and the outer portion.

16. In paragraph 11, The above secondary battery, A plurality of said first cells aligned in a first direction; A secondary battery comprising a plurality of said second cells aligned in a first direction.

17. In paragraph 11, The first electrode lead includes a first positive electrode lead and a first negative electrode lead, A secondary battery wherein the second electrode lead includes a second positive electrode lead and a second negative electrode lead.

18. In paragraph 17, The above hollow conductor, An anode lead electrically connected to the first anode lead and the second anode lead; and A secondary battery comprising a negative electrode lead electrically connected to the first negative electrode lead and the second negative electrode lead.

19. In paragraph 11, Each of the first electrode assembly and the second electrode assembly, A unit cell in which a first cathode, a first solid electrolyte layer, an anode, a second solid electrolyte layer, and a second cathode are sequentially arranged; and A secondary battery in which a plurality of the above unit cells are stacked and an elastic sheet is included between the first negative electrode and the second negative electrode of adjacent unit cells.

20. In paragraph 11, A secondary battery further comprising a cooling means connected to the hollow conductor and configured to allow a refrigerant to flow and exchange heat of the refrigerant.

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