All-solid-state batteries containing composite electrodes

Abstract

To provide an all-solid battery that has high-capacity, high-energy density characteristics by applying electrodes having a large calorific value to some electrodes of an electrode assembly and thereby raising the own battery temperature by heat generated in a normal operation environment of the battery.SOLUTION: Provided is an all-solid battery that includes an electrode assembly and a solid electrolyte. The electrode assembly has a structure in which plate-like electrodes are laminated. The electrode includes a relatively high heat-generating first electrode and a relatively low heat-generating second electrode. The first electrode is located at the center part of the electrode assembly. An all-solid battery with improved performance can be provided by increasing battery temperature without adding additional members.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 2019-0053694 filed on May 8, 2019, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to an all-solid-state battery including a composite electrode that can compensate for the poor electrochemical performance of the all-solid-state battery by disposing an electrode with a high heat generation amount at the center of the electrode assembly. [Background technology]

[0003] 2. Description of the Related Art As mobile electronic devices, including mobile phones, become more multifunctional, the demand for high-energy density lithium secondary batteries is increasing.

[0004] Furthermore, in order to use lithium secondary batteries in power storage devices and electric vehicles that require a large-capacity, high-output energy source, active research is being conducted on improving the safety and increasing the voltage of lithium secondary batteries.

[0005] Lithium ion secondary batteries, which are a type of lithium secondary battery, have the advantages of higher energy density, lower self-discharge rate, and longer life than nickel manganese batteries or nickel cadmium batteries, but have been pointed out as having disadvantages such as safety issues due to overheating.

[0006] In order to overcome the problems of the lithium-ion secondary battery, an all-solid-state battery has been proposed as an alternative. The all-solid-state battery may have a structure including an electrolyte layer including a solid electrolyte, a positive electrode layer and a negative electrode layer including the solid electrolyte and formed on both sides of the electrolyte layer, and a current collector is bonded to each of the positive electrode layer and the negative electrode layer.

[0007] The all-solid-state battery is superior in safety compared to existing lithium-ion secondary batteries, but has a problem in that performance such as capacity and output is inferior due to low ionic conductivity of the solid electrolyte.

[0008] To solve these problems, a technology that utilizes the characteristic of all-solid-state batteries, in which ionic conductivity increases significantly as temperature increases, has been proposed as an alternative.

[0009] Specifically, Patent Document 1 relates to a secondary battery in which a heat generating means insulated from the electrodes is located on an electrode current collector, and the battery is provided with a temperature control means and a current flow control means for sensing the internal temperature of the battery and controlling the flow of electricity to the heat generating means.

[0010] If a separate heating means is provided as in Patent Document 1, the overall size of the battery increases and the energy density decreases, and if a separate power source is required for the external heating means, there is a problem of energy waste.

[0011] Patent Document 2 relates to a nonaqueous electrolyte secondary battery that includes a PTC layer between a positive electrode active material layer and a positive electrode current collector, and the PTC layer is composed of an aggregate of conductive particles, thereby blocking the flow of current under heat generation conditions caused by overcharging of the battery, etc., and thereby suppressing heat generation from the battery.

[0012] Patent Document 3 relates to a non-aqueous secondary battery having a structure in which an electrode collector is covered with a conductive layer containing a crystalline thermoplastic resin having a positive temperature coefficient of resistance function in which the resistance value increases when the temperature rises, a conductive material, and an adhesive.

[0013] The above-mentioned Patent Documents 2 and 3 only disclose a technique for preventing the generation of heat by cutting off the current when the temperature of the battery increases, but do not provide a method for maintaining the heat generation state of the battery.

[0014] Patent Document 4 relates to a battery cell in which a heating element that dissipates resistance heat by interaction within the battery is located on one or both sides of a unit cell located in the center of an electrode assembly.

[0015] Patent Document 4 discloses a battery cell including a heating element that increases the internal temperature of the battery. However, the battery cell including the heating element increases in thickness or the thickness of the electrode assembly decreases relatively, resulting in a problem of reduced energy density.

[0016] Therefore, there is a strong need for a technology that can improve the function of a battery by increasing the battery temperature of an all-solid-state battery, and can prevent a decrease in energy density due to an increase in the volume of a battery cell and the need for a separate external power source. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Patent No. 5314872 [Patent Document 2] JP 2009-176599 A [Patent Document 3] JP 2001-357854 A [Patent Document 4] Korean Patent No. 1760647 Summary of the Invention [Problem to be solved by the invention]

[0018] The present invention aims to provide an all-solid-state battery having high capacity and high energy density characteristics by applying an electrode with a large heat generation amount to some of the electrodes of an electrode assembly, thereby increasing the temperature of the battery by heat generated in a normal operating environment of the battery. [Means for solving the problem]

[0019] To achieve the above object, the all-solid-state battery according to the present invention includes an electrode assembly and a solid electrolyte, the electrode assembly having a structure in which plate-shaped electrodes are stacked, the electrodes including a first electrode having a relatively high heat generation property and a second electrode having a relatively low heat generation property, and the first electrode is located at a center of the electrode assembly.

[0020] In one embodiment, the electrode assembly is a stack-type electrode assembly, the first electrode and the second electrode have the same active material composition, and the solid electrolyte content of the first electrode may be higher than the solid electrolyte content of the second electrode.

[0021] Alternatively, the electrode assembly may be a lamination / stack type electrode assembly or a stack / folding type electrode assembly including a plurality of unit cells, the unit cells may include a first unit cell constituted by the first electrode and a second unit cell constituted by the second electrode, the first electrode and the second electrode may have the same active material composition, and the solid electrolyte content of the first electrode may be higher than the solid electrolyte content of the second electrode.

[0022] In another embodiment, the electrode assembly is a stack type electrode assembly, and the first electrode active material and the second electrode active material may be selected from among hard carbon, soft carbon, artificial graphite, natural graphite coated with artificial graphite, natural graphite, and silicon oxide, and may be selected from a relatively high heat generating negative electrode active material and a relatively low heat generating negative electrode active material.

[0023] Alternatively, the electrode assembly may be a lamination / stack type electrode assembly or a stack / folding type electrode assembly including a plurality of unit cells, the unit cell including a first unit cell constituted by the first electrode and a second unit cell constituted by the second electrode, and the active material of the first electrode and the active material of the second electrode may be a negative electrode active material having a relatively high heat generation property and a negative electrode active material having a relatively low heat generation property selected from among hard carbon, soft carbon, artificial graphite, natural graphite coated with artificial graphite, natural graphite, and silicon oxide.

[0024] In addition, each of the first and second unit cells may include a uniform active material.

[0025] The electrodes can be positive, negative, or positive and negative.

[0026] The solid electrolyte may be a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a polymer-based solid electrolyte.

[0027] Heat from the first electrode is transferred to the second electrode, thereby increasing the temperature inside the battery.

[0028] The solid-state battery is composed of a single electrode and can have a larger capacity at sub-zero temperatures compared to a solid-state battery having the same capacity at room temperature.

[0029] The present invention provides a battery pack including the all-solid-state battery, and a device including the battery pack, The device may be one selected from the group consisting of a mobile electronic device, a wearable electronic device, a tablet computer, a notebook computer, an electric vehicle, and a power storage device. [Brief description of the drawings]

[0030] [Figure 1] FIG. 2 is a side view of a stacked electrode assembly including multiple positive and negative electrodes. [Diagram 2] FIG. 2 is a side view of a stack / folding type electrode assembly according to the present invention. [Diagram 3] FIG. 2 is a side view of a lamination / stack type electrode assembly according to the present invention. [Figure 4] 1 is a graph showing the results of Experimental Example 1. [Diagram 5] 13 is a graph showing the results of Experimental Example 2. [Figure 6] 13 is a graph showing the results of Experimental Example 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, in which a person having ordinary skill in the art to which the present invention pertains can easily carry out the present invention. However, in describing the operation principle of the preferred embodiment of the present invention in detail, detailed description of related well-known functions or configurations will be omitted if it is determined that such detailed description may unnecessarily obscure the gist of the present invention.

[0032] In addition, parts having similar functions and actions are designated by the same reference numerals throughout the drawings. Throughout the specification, when a part is said to be connected to another part, this includes not only the case where the part is directly connected to another part, but also the case where the part is indirectly connected via another element between the two parts. In addition, when a part includes a certain component, it does not mean that the other component is excluded, but that the part may further include the other component, unless otherwise specified.

[0033] The present invention relates to an all-solid-state battery including an electrode assembly and a solid electrolyte, and the electrode assembly has a structure in which plate-shaped electrodes are stacked.

[0034] In general, the structure of an electrode assembly can be classified into a stack type electrode assembly in which plate-shaped electrodes are stacked, a stack / folding type electrode assembly, a lamination / stack type electrode assembly, and a jelly roll type electrode assembly in which a long sheet-shaped electrode is wound up.

[0035] The jelly-roll type electrode assembly includes one positive electrode and one negative electrode, making it difficult to diversify the electrode configuration. On the other hand, the stack type, stack / folding type, and lamination / stack type electrode assemblies are configured by stacking a plurality of plate-shaped electrodes, making it possible to apply various types of positive electrodes and negative electrodes.

[0036] Therefore, the electrode assembly of the all-solid-state battery according to the present invention may include a first electrode having a relatively high heat generation property and a second electrode having a relatively low heat generation property, and the first electrode may be located at the center of the electrode assembly.

[0037] As used herein, a high heat generating first electrode is an electrode that generates a relatively high amount of heat and uses a high heat generating active material or has a higher content ratio of solid electrolyte than the second electrode, and a low heat generating second electrode is an electrode that generates a relatively low amount of heat compared to the first electrode and uses a low heat generating active material or has a lower content ratio of solid electrolyte than the first electrode.

[0038] Since the first electrode may be located at the center of the electrode assembly, the first electrode may be disposed at the center of an electrode assembly composed of a plurality of electrodes, or a unit cell including or composed of the first electrode may be disposed at the center of the electrode assembly. By disposing the first electrode, which has high heat generation, at the center of the electrode assembly, heat from the first electrode is transferred to the second electrode, thereby increasing the internal temperature of the battery.

[0039] Generally, a first electrode having high heat generation may have reduced life characteristics due to damage to the active material or the internal structure of the electrode caused by a high rate, whereas a second electrode having low heat generation and a relatively stable rate may have relatively excellent life characteristics due to less damage to the active material or the internal structure of the electrode.

[0040] Therefore, when the electrode assembly includes a first electrode that generates high heat due to an increase in the overall temperature and a second electrode that has stable life characteristics, the inferior parts of the first electrode and the second electrode can complement each other.

[0041] In this regard, FIG. 1 shows a side view of a stacked electrode assembly including multiple positive and negative electrodes.

[0042] Referring to FIG. 1(a), an electrode assembly 100 is a stack-type electrode assembly having a structure in which a plurality of positive electrodes 101, 101' and negative electrodes 102 are stacked with a solid electrolyte layer 103 sandwiched therebetween.

[0043] The positive electrode 101' located in the center of the electrode assembly 100 is a first positive electrode with high heat generation, and the positive electrode 101 located on the outer side of the electrode assembly 100 is a second positive electrode with low heat generation. In addition, in consideration of the performance of the battery, the two negative electrodes 102 can be simultaneously or selectively used as the first negative electrode with high heat generation or the second negative electrode with low heat generation. By disposing the positive electrode with high heat generation in the center of the electrode assembly in this manner, thermal energy can be transferred to both sides based on the stacking direction of the electrodes, so that the internal temperature of the battery can be increased uniformly.

[0044] An electrode assembly 110 shown in FIG. 1(b) is a stack-type electrode assembly having a structure in which a plurality of positive electrodes 111 and a plurality of negative electrodes 112, 112' are stacked with a solid electrolyte layer 113 sandwiched therebetween.

[0045] The negative electrode 112' located at the center of the electrode assembly 110 may be a first negative electrode having a high heat generation property, and the negative electrode 112 located on the outer side is a second negative electrode having a low heat generation property.

[0046] In addition, in consideration of the performance of the battery, the two positive electrodes 111 can be simultaneously or selectively used as a first positive electrode having high heat generation or a second positive electrode having low heat generation. By disposing a negative electrode having high heat generation in the center of the electrode assembly, thermal energy can be transferred to both electrodes based on the stacking direction of the electrodes, so that the internal temperature of the battery can be increased uniformly.

[0047] In one embodiment, the positive electrode 101 and the positive electrode 101', and the negative electrode 112 and the negative electrode 112' may have different solid electrolyte contents but may have the same active material composition.

[0048] For example, anode 112 and anode 112' can be synthetic graphite, natural graphite, synthetic graphite coated natural graphite, silicon oxide, hard carbon, or soft carbon.

[0049] Additionally, the positive electrode 101 and the positive electrode 101' can be Ni-Co-Mn oxide (LiNCMO2 (LiNCM)), lithium nickel oxide (LiNiO2 (LNO)), an oxide with an olivine structure (LFP (LiFePO4) or LiMnPO4 (LMP)), lithium cobalt oxide (LiCoO2 (LCO)), or lithium manganese oxide (LiMn2O4 (LMO)).

[0050] In another embodiment, the positive electrode 101' and the negative electrode 112' may be made of a high heat generating electrode active material, and the positive electrode 101 and the negative electrode 112 may be made of a low heat generating electrode active material.

[0051] Negative electrode active materials, ranked from most heat-generating to least heat-generating, are hard carbon > soft carbon > artificial graphite > natural graphite coated with artificial graphite > natural graphite > silicon oxide. Positive electrode active materials, ranked from most heat-generating to least heat-generating, are LMO > LCO > LiNCM > LNO > LMP, LFP.

[0052] Since the positive electrode 101' and the negative electrode 112' have a relatively higher heat generation property than the positive electrode 101 and the negative electrode 112, it is possible to selectively apply positive electrodes and negative electrodes having a relatively high heat generation property and positive electrodes and negative electrodes having a relatively low heat generation property in consideration of the magnitude of the heat generation property described above.

[0053] Alternatively, the positive and negative electrode active materials may be selected from among electrode active materials classified into a high heat generation group and a low heat generation group.

[0054] For example, the negative electrode 112 may be one or more selected from the group consisting of artificial graphite, natural graphite, natural graphite coated with artificial graphite, and silicon oxide, and the negative electrode 112' may be one or more selected from the group consisting of hard carbon and soft carbon.

[0055] The positive electrode 101 can be one or more selected from the group consisting of Ni-Co-Mn oxide with Ni content exceeding 60% (LiNCMO2, Ni>60%), lithium nickel oxide (LiNiO2(LNO)) and oxide with an olivine structure (LFP(LiFePO4) or LiMnPO4(LMP)), and the positive electrode 101' can be one or more selected from the group consisting of lithium cobalt oxide (LiCoO2(LCO)), lithium manganese oxide (LiMn2O4(LMO)) and Ni-Co-Mn oxide with Ni content of 60% or less (LiNCMO2, Ni<60%).

[0056] FIG. 2 is a side view of a stack / folding type electrode assembly according to the present invention.

[0057] Referring to FIG. 2, the electrode assembly 200 is a stack / folding type electrode assembly in which unit cells 210, 220, 230, 240, 250, 260, 270, and 280 in a bi-cell form having a structure of positive electrode / solid electrolyte layer / negative electrode / solid electrolyte layer / positive electrode or a structure of negative electrode / solid electrolyte layer / positive electrode / solid electrolyte layer / negative electrode are positioned on one side of a solid electrolyte layer 290, and the solid electrolyte layer is compressed. A fixing tape 291 is attached to an end of the solid electrolyte layer 290 to prevent the solid electrolyte layer from being separated.

[0058] The electrode assembly 200 is composed of eight unit cells. The unit cells 210, 220, 230, and 240 located in the center are first unit cells including a first electrode with high heat generation, which includes an active material with a high solid electrolyte content or high heat generation, compared to the unit cells 250, 260, 270, and 280 located on the outside, and the unit cells 250, 260, 270, and 280 are second unit cells including a second electrode with low heat generation.

[0059] Specifically, both the positive electrode and the negative electrode constituting the first unit cell may be a first positive electrode and a first negative electrode having high heat generation properties, or only one of the positive electrode and the negative electrode of the first unit cell may be a first positive electrode or a first negative electrode having high heat generation properties.

[0060] However, the positive electrode and the negative electrode constituting the second unit cell may be a second positive electrode and a second negative electrode each having low heat generation.

[0061] As described with reference to FIG. 1, the first positive electrode and the first negative electrode, and the second positive electrode and the second negative electrode may be configured in the same manner, either in the case where (i) the solid electrolyte content ratio is different and the same type of electrode active material is used, or in the case where (ii) an electrode active material having a relatively high calorific value and an electrode active material having a relatively low calorific value are used.

[0062] Unlike the example shown in FIG. 2, only two first unit cells are applied at the center, and the remaining six unit cells excluding the first unit cells may be applied as second unit cells, or the unit cells 270 and 280 located at the outermost part of the electrode assembly may be applied as second unit cells, and the remaining six unit cells excluding the first unit cells may be applied as first unit cells.

[0063] In the electrode assembly 200 of FIG. 2, the positive and negative electrodes constituting the first unit cells 210, 220, 230, and 240 may be designed to have the same electrode constituent materials, such as active materials, conductive materials, and solid electrolytes, or may be designed to selectively have different types and / or composition ratios of the electrode constituent materials while generating a higher heat value than the second unit cell.

[0064] In addition, the positive and negative electrodes constituting the second unit cells 250, 260, 270, and 280 may be designed to have the same electrode constituent materials, such as an active material, a conductive material, and a solid electrolyte, or may be designed to selectively have different types and / or composition ratios of the electrode constituent materials while generating a lower amount of heat than the first unit cell.

[0065] FIG. 3 is a side view of a lamination / stack type electrode assembly according to the present invention.

[0066] Referring to FIG. 3, the electrode assembly 300 is a lamination / stack type electrode assembly in which unit cells 310, 320, 330, 340, 350, 360, 370, and 380 in a bi-cell form having a structure of a positive electrode / solid electrolyte layer / negative electrode / solid electrolyte layer / positive electrode or a structure of a negative electrode / solid electrolyte layer / positive electrode / solid electrolyte layer / negative electrode are stacked with a solid electrolyte layer 390 sandwiched therebetween and heat-sealed.

[0067] In the electrode assembly 300, unit cells 330, 340, 350, and 360 located in the center are high-heat-generating unit cells having properties corresponding to unit cells 210, 220, 230, and 240, which are the first unit cells in FIG. 2, and unit cells 310, 320, 370, and 380 located in the outer periphery are low-heat-generating unit cells having properties corresponding to unit cells 250, 260, 270, and 280, which are the second unit cells in FIG. 2.

[0068] Therefore, the description of the unit cells 330, 340, 350, 360 and the unit cells 310, 320, 370, 380 of the electrode assembly 300 can be applied in the same manner as the description of the unit cells 210, 220, 230, 240 and the unit cells 250, 260, 270, 280 of the electrode assembly 200.

[0069] The solid electrolyte may be a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a polymer-based solid electrolyte.

[0070] The sulfide-based solid electrolyte preferably contains a sulfur atom (S), has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and has electrical insulation. The sulfide-based solid electrolyte preferably contains at least Li, S, and P as elements and has lithium ion conductivity, but may contain elements other than Li, S, and P depending on the purpose or circumstances.

[0071] Specific examples of sulfide-based solid electrolytes are shown below. For example, Li2S-P2S5, Li2S-P2S5-LiCl, Li2S-P2S5-H2S, Li2S-P2S5-H2S-LiCl, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2SLi2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2O5, Li2S-P2S5-SiS2, Li2S-P2S5-SiS2-LiCl, Li2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-GeS2, Li2S-GeS2-ZnS, Li2S-Ga2S3, Li2S-GeS2-Ga2S3, Li2S-GeS2-P2S5, Li2S-GeS2-Sb2S5, Li2S-GeS2-Al2S3, Li2S-SiS2, Li2 S-Al2S3, Li2S-SiS2-Al2S3, Li2S-SiS2-P2S5, Li2S-SiS2-P2S5-LiI, Li2S-SiS2-LiI, Li2S-SiS2-Li4SiO4, Li2S-SiS2-Li3PO4, and Li 10 GeP2S 12 Some examples include:

[0072] Examples of methods for synthesizing sulfide-based solid electrolyte materials include amorphization methods, such as mechanical milling, solution methods, and melt quenching methods, among which the mechanical milling method is preferred because it can be performed at room temperature (25° C.) and has the advantage of simplifying the manufacturing process.

[0073] The oxide-based solid electrolyte is preferably a compound that contains an oxygen atom (O), has the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and has electrical insulation properties.

[0074] As the oxide-based solid electrolyte, for example, Li xa La ya TiO3(xa=0.3~0.7, ya=0.3~0.7)(LLT), Li xb La yb Zr zb M bb mbO nb (M bb is at least one element selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, and Sn, xb satisfies 5≦xb≦10, yb satisfies 1≦yb≦4, zb satisfies 1≦zb≦4, mb satisfies 0≦mb≦2, and nb satisfies 5≦nb≦20), Li xc B yc M cc zc O nc (M cc is at least one element selected from the group consisting of C, S, Al, Si, Ga, Ge, In, and Sn, where xc satisfies 0≦xc≦5, yc satisfies 0≦yc≦1, zc satisfies 0≦zc≦1, and nc satisfies 0≦nc≦6), Li xd (Al, Ga) yd (Ti, Ge) zd S ad P md O nd (where 1≦xd≦3, 0≦yd≦1, 0≦zd≦2, 0≦ad≦1, 1≦md≦7, 3≦nd≦13), Li (3-2xe) M ee xe D ee O (where 0≦xe≦0.1, M ee is a divalent metal atom, D ee is a halogen atom or a combination of two or more halogen atoms), Li xf S yf O zf (1≦xf≦5, 0 <yf≦3、1≦zf≦10)、Li xg S yg O zg (1≦xg≦3, 0 <yg≦2、1≦zg≦10)、Li3BO3-Li2SO4、Li2O-B2O3-P2O5、Li2O-SiO2、Li6BaLa2Ta2O 12 , LiPO (4-3 / 2w) N w (w is w<1), Li with LISICON (Lithium super ionic conductor) type crystal structure 3.5 Zinc 0.25 GeO4, La with perovskite crystal structure 0.55 Li 0.35TiO3, LiTi2P3O with NASICON (sodium super ionic conductor) type crystal structure 12 , Li 1+xh+yh (Al, Ga) xh (Ti, Ge) 2-xh S yh P 3-yh O 12 (where 0≦xh≦1, 0≦yh≦1), and Li7La3Zr2O having a garnet-type crystal structure 12 (LLZ) and the like. Phosphorus compounds containing Li, P, and O are also preferred. For example, lithium phosphate (Li3PO4), LiPON in which part of the oxygen in lithium phosphate is replaced with nitrogen, and LiPOD 1 (D 1 can be at least one selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, Au, etc. 1 ON (A1 is at least one selected from Si, B, Ge, Al, C, Ga, etc.) can also be preferably used.

[0075] The polymer solid electrolyte may be a solid polymer electrolyte formed by adding a polymer resin to a lithium salt that has been independently solvated, or a polymer gel electrolyte formed by impregnating an organic electrolyte solution containing an organic solvent and a lithium salt in a polymer resin.

[0076] For example, the solid polymer electrolyte is an ion-conductive material and is not particularly limited as long as it is a polymer material generally used as a solid electrolyte material for all-solid-state batteries. The solid polymer electrolyte may include, for example, polyether-based polymers, polycarbonate-based polymers, acrylate-based polymers, polysiloxane-based polymers, phosphagen-based polymers, polyethylene derivatives, alkylene oxide derivatives, phosphate ester polymers, polyagitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, and polymers containing ionic dissociation groups. In a specific embodiment of the present invention, the solid polymer electrolyte may include, as a polymer resin, a branched copolymer in which an amorphous polymer such as polymethyl methacrylate (PMMA), polycarbonate, polysiloxane, and / or phosphagen is copolymerized with a comonomer on a polyethylene oxide (PEO) main chain, a comb-like polymer resin, and a crosslinked polymer resin.

[0077] The polymer gel electrolyte includes an organic electrolyte solution containing a lithium salt and a polymer resin, and the organic electrolyte solution is included in an amount of 60 to 400 parts by weight based on the weight of the polymer resin. The polymer resin applied to the polymer gel electrolyte is not limited to a specific component, and may include, for example, polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), and polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP).

[0078] The lithium salt is an ionizable lithium salt, Li + X - The anion of such a lithium salt is not particularly limited, but may be F- , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - The following can be given as examples:

[0079] Hereinafter, the present invention will be described with reference to examples, which are provided for easier understanding of the present invention and are not intended to limit the scope of the present invention.

[0080] <Example 1> As shown in FIG. 3, a lamination / stack type electrode assembly including eight unit cells was manufactured.

[0081] Among the unit cells, one high heat generating unit cell was disposed in the center, and seven low heat generating unit cells were disposed on both sides of the high heat generating unit cell, thereby completing an electrode assembly including a total of eight unit cells.

[0082] The highly heat-generating unit cell uses LiNi as the positive electrode active material. 0.8 Co 0.1Mn 0.1 The positive electrode was fabricated using 75% by weight of O2, 5% by weight of Super C as a conductive material, 15% by weight of polyethylene oxide (PEO) as a solid electrolyte, and 5% by weight of polyvinylidene fluoride (PVDF) as a binder, and the negative electrode was fabricated using 71% by weight of artificial graphite as a negative electrode active material, 2% by weight of Super C as a conductive material, 23% by weight of polyethylene oxide (PEO) as a solid electrolyte, and 4% by weight of styrene butylene rubber (SBR) + carboxyl methyl cellulose (CMC) as a binder.

[0083] The low heat generating unit cell uses LiNi as a positive electrode active material. 0.8 Co 0.1 Mn 0.1 The positive electrode was fabricated using 85% by weight of O2, 3% by weight of Super C as a conductive material, 8% by weight of polyethylene oxide (PEO) as a solid electrolyte, and 4% by weight of polyvinylidene fluoride (PVDF) as a binder, and the negative electrode was fabricated using 83% by weight of artificial graphite as a negative electrode active material, 1% by weight of Super C as a conductive material, 13% by weight of polyethylene oxide (PEO) as a solid electrolyte, and 3% by weight of styrene butylene rubber (SBR) + carboxyl methyl cellulose (CMC) as a binder.

[0084] The solid electrolyte layer interposed between the positive and negative electrodes is prepared by dissolving polyethylene oxide and LiFSI in acetonitrile at a ratio of 20 mol% and 1 mol%, casting the resulting solution thinly on a glass plate, and then drying the resulting solution in a vacuum to a thickness of 100 μm.

[0085] <Example 2> An electrode assembly was manufactured in the same manner as in Example 1, except that the number of high heat-generating unit cells located in the center of the electrode assembly was two and the number of low heat-generating unit cells was six.

[0086] <Example 3> An electrode assembly was manufactured in the same manner as in Example 1, except that the number of high heat-generating unit cells located in the center of the electrode assembly was three and the number of low heat-generating unit cells was five.

[0087] <Example 4> An electrode assembly was manufactured in the same manner as in Example 1, except that the number of high heat-generating unit cells located in the center of the electrode assembly was four, and the number of low heat-generating unit cells was four.

[0088] <Comparative Example 1> As shown in FIG. 3, a lamination / stack type electrode assembly including eight unit cells was manufactured.

[0089] The unit cells all include electrodes having the same heat generating properties.

[0090] Specifically, LiNi 0.8 Co 0.1 Mn 0.1 The positive electrode was fabricated using 80% by weight of O2, 4% by weight of Super C as a conductive material, 10% by weight of polyethylene oxide (PEO) as a solid electrolyte, and 6% by weight of polyvinylidene fluoride (PVDF) as a binder, and the negative electrode was fabricated using 77% by weight of artificial graphite as a negative electrode active material, 1.5% by weight of Super C as a conductive material, 18% by weight of polyethylene oxide (PEO) as a solid electrolyte, and 3.5% by weight of styrene butylene rubber (SBR) + carboxyl methyl cellulose (CMC) as a binder.

[0091] The electrode assembly of Comparative Example 1 was designed to have the same capacity as the electrode assemblies of Examples 1 to 4 at room temperature.

[0092] <Experimental Example 1> In order to confirm the level of improvement in low-temperature capacity of the electrode assemblies including the highly heat-generating electrodes, the secondary batteries including the electrode assemblies prepared in Examples 1 to 4 and Comparative Example 1 were fully charged and fully discharged at -10°C, and the ratio of the improved capacity to the capacity of Comparative Example 1 is shown in FIG. 4.

[0093] Referring to FIG. 4, it can be seen that the battery capacity tends to increase as the number of highly heat-generating unit cells increases.

[0094] The above experiment was carried out under low temperature conditions, and it can be seen that the present invention has a superior effect of improving capacity at low temperatures.

[0095] <Example 5> As shown in FIG. 3, a lamination / stack type electrode assembly including eight unit cells was manufactured.

[0096] Among the unit cells, four high heat generating unit cells were arranged in the center, and two low heat generating unit cells were arranged on each side of the high heat generating unit cells, thereby completing an electrode assembly including a total of eight unit cells.

[0097] The highly heat-generating unit cell is Man-made The negative electrode was manufactured using 80% by weight of graphite, 2% by weight of Super C as a conductive material, 13% by weight of polyethylene oxide (PEO) as a solid electrolyte, and 5% by weight of styrene butylene rubber (SBR) + carboxyl methyl cellulose (CMC) as a binder, and LiNi as a positive electrode active material. 0.8 Co 0.1 Mn 0.1 The cathode was fabricated using 80% by weight of O2, 4% by weight of Super C as a conductive material, 10% by weight of polyethylene oxide (PEO) as a solid electrolyte, and 6% by weight of PVDF as a binder.

[0098] The low heat generating unit cell is the negative electrode active material used in the high heat generating unit cell. Man-made Instead of graphite naturalThe high heat generating unit cell was fabricated in the same manner as described above, except that graphite was used.

[0099] The solid electrolyte layer interposed between the positive and negative electrodes was prepared by dissolving polyethylene oxide and LiFSI in acetonitrile at a ratio of 20 mol% and 1 mol%, casting the resulting solution thinly on a glass plate, and then drying the solution in a vacuum to a thickness of 100 μm.

[0100] <Example 6> The high heat generating negative electrode used in Example 5 Man-made An electrode assembly was manufactured in the same manner as in Example 5, except that soft carbon was used instead of graphite.

[0101] <Example 7> The high heat generating negative electrode used in Example 5 Man-made An electrode assembly was manufactured in the same manner as in Example 5, except that hard carbon was used instead of graphite.

[0102] <Comparative Example 2> As shown in FIG. 3, a lamination / stack type electrode assembly including eight unit cells was manufactured.

[0103] The unit cells all include electrodes having the same heat generating properties.

[0104] Specifically, the unit cell contains a negative electrode active material natural An electrode assembly was prepared using the same positive electrode and solid electrolyte as in Example 5, except that a negative electrode containing graphite was used.

[0105] The electrode assembly of Comparative Example 2 was designed to have the same capacity as the electrode assemblies of Examples 5 to 7 at room temperature.

[0106] <Experimental Example 2> In order to confirm the level of low-temperature capacity improvement by applying negative electrode active materials having different heat generation properties, the secondary batteries including the electrode assemblies prepared in Examples 5 to 7 and Comparative Example 2 were fully charged and fully discharged at -10°C, and the ratio of the improved capacity to the capacity of Comparative Example 2 is shown in FIG. 5.

[0107] Referring to FIG. 5, it can be seen that the capacity of the battery is increased depending on the type of negative electrode active material. Artificial graphite, It was confirmed that the battery capacity increases in the order of soft carbon and hard carbon.

[0108] The above experiment was carried out under low temperature conditions, and it can be seen that the present invention has a superior effect of improving capacity at low temperatures.

[0109] <Comparative Example 3> An electrode assembly was manufactured in the same manner as in Example 1, except that two high-heat-generating unit cells manufactured in Example 1 were disposed at both ends of the electrode assembly and six low-heat-generating unit cells were disposed in the center to manufacture a lamination / stack type electrode assembly including eight unit cells as shown in FIG. 3.

[0110] <Experimental Example 3> In order to confirm the level of improvement in battery capacity depending on the position of the highly heat-generating electrode, the secondary batteries including the electrode assemblies prepared in Example 2 and Comparative Example 3 were fully charged and fully discharged at 10° C., and the ratio of the improved capacity to the capacity of Comparative Example 1 is shown in FIG. 6.

[0111] Referring to FIG. 6, it can be seen that the secondary battery including the electrode assembly of Example 2 has a capacity improvement effect of about 3.5% compared to the secondary battery including the electrode assembly of Comparative Example 1 composed only of electrodes having a uniform heat generation amount.

[0112] However, it was confirmed that the secondary battery including the electrode assembly of Comparative Example 3, in which highly heat-generating unit cells were arranged only at both ends of the electrode assembly, had a lower battery capacity than the secondary battery including the electrode assembly of Comparative Example 1.

[0113] Therefore, when the number of highly heat-generating electrodes is the same, the capacity is significantly increased when the electrodes are arranged at the center of the electrode assembly compared to when the electrodes are arranged at both ends.

[0114] Those skilled in the art will appreciate that various applications and modifications within the scope of the present invention are possible based on the above content. [Industrial Applicability]

[0115] As described above, since the all-solid-state battery including the composite electrode according to the present invention partially includes an electrode having a high heat generation amount, it is possible to obtain an effect that the overall temperature of the battery increases due to the thermal energy generated during normal use of the battery.

[0116] In addition, by applying an electrode assembly including both high heat generation electrodes and low heat generation electrodes, it is possible to obtain not only the effect of temperature increase due to the high heat generation electrodes, but also the effect of improving the life span due to the low heat generation electrodes.

[0117] In addition, since no separate heat generating member is added for heat generation, an additional external power source is not required, and therefore an increase in the volume of the battery due to the provision of an external power source can be prevented. [Explanation of symbols]

[0118] 100, 110, 200, 300 electrode assemblies 101, 101', 111 positive electrode 102, 112, 112' negative pole 103, 113, 290, 390 solid electrolyte layer 210, 220, 230, 240, 250, 260, 270, 280, 310, 320, 330, 340, 350, 360, 370, 380 unit cell 291 Fixing Tape

Claims

1. An all-solid-state battery including an electrode assembly and a solid electrolyte, The electrode assembly has a structure in which plate-shaped electrodes are stacked, the electrodes include one or more first electrodes and a plurality of second electrodes; the first electrode has a higher heat generation amount than the second electrode; the first electrode is located at a center of the electrode assembly, When the all-solid-state battery is charged and discharged at a predetermined current in a normal operating environment, the amount of heat generated by the first electrode is greater than the amount of heat generated by the second electrode; the electrode assembly is a stacked electrode assembly, The first electrodes have the same active material composition, The second electrodes have the same active material composition, When the magnitude of the calorific value of the negative electrode active material is in the order of hard carbon>soft carbon>artificial graphite>natural graphite coated with artificial graphite>natural graphite>silicon oxide, the first electrode active material is a negative electrode active material having a relatively high calorific value, and the second electrode active material is a negative electrode active material having a relatively low calorific value, The all-solid-state battery, wherein the first electrode and the second electrode are negative electrodes.

2. An all-solid-state battery comprising an electrode assembly and a solid electrolyte, The electrode assembly has a structure in which plate-shaped electrodes are stacked, the electrodes include one or more first electrodes and a plurality of second electrodes; the first electrode has a higher heat generation amount than the second electrode; the first electrode is located at a center of the electrode assembly, When the all-solid-state battery is charged and discharged at a predetermined current in a normal operating environment, the amount of heat generated by the first electrode is greater than the amount of heat generated by the second electrode; The electrode assembly is a lamination / stack type electrode assembly or a stack / folding type electrode assembly including a plurality of unit cells, the unit cell includes a first unit cell configured with the first electrode and a second unit cell configured with the second electrode, The first electrodes have the same active material composition, The second electrodes have the same active material composition, When the magnitude of the calorific value of the negative electrode active material is in the order of hard carbon>soft carbon>artificial graphite>natural graphite coated with artificial graphite>natural graphite>silicon oxide, the first electrode active material is a negative electrode active material having a relatively high calorific value, and the second electrode active material is a negative electrode active material having a relatively low calorific value, The all-solid-state battery, wherein the first electrode and the second electrode are negative electrodes.

3. The all-solid-state battery according to claim 2 , wherein each of the first unit cell and the second unit cell contains the same active material.

4. 3. The all-solid-state battery according to claim 1, wherein the solid electrolyte is a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a polymer-based solid electrolyte.

5. The all-solid-state battery according to claim 1 or 2, wherein heat from the first electrode is transferred to the second electrode, thereby increasing a temperature inside the battery.

6. A battery pack comprising the all-solid-state battery according to any one of claims 1 to 5.

7. A device including the battery pack of claim 6, The device is one selected from the group consisting of a mobile electronic device, a wearable electronic device, a tablet computer, a notebook computer, an electric vehicle, and a power storage device.

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