All-solid-state battery

Abstract

The present invention relates to an all-solid-state battery, more specifically to an all-solid-state battery comprising: a first laminate including one or more first battery cells and one or more first elastic pads; a first pouch enclosing the first laminate; a first end plate on the first laminate; a second end plate under the first laminate, the first and second end plates sandwiching the first laminate; and a first metal spring pad interposed between the first and second end plates.

Description

All-solid-state batteries

[0001] The present invention relates to an all-solid-state battery.

[0002] Recent industrial demands have led to the active development of batteries with high energy density and safety. For example, lithium-ion batteries are being used not only in information and communication devices, but also in the automotive sector. Safety is particularly important in the automotive sector, as it is directly related to life.

[0003] All-solid-state batteries do not use flammable organic dispersion media, significantly reducing the risk of fire or explosion even if a short circuit occurs. Consequently, these all-solid-state batteries can boast excellent safety.

[0004] The problem to be solved by the present invention is to provide an all-solid-state battery with a long lifespan.

[0005] Another problem to be solved by the present invention is to provide an all-solid-state battery that can be used over a wide temperature range.

[0006] According to one embodiment of the present invention, an all-solid-state battery may include: a first laminate including at least one first battery cell and at least one first elastic pad; a first pouch enclosing the first laminate; a first end plate on the first laminate; a second end plate below the first laminate, the first and second end plates sandwiching the first laminate; and a first metal spring pad interposed between the first and second end plates.

[0007] The all-solid-state battery according to the present invention can be used at high and low temperatures and can have excellent life characteristics.

[0008] FIG. 1 is a plan view illustrating an all-solid-state battery according to embodiments of the present invention.

[0009] FIG. 2 is a cross-sectional view illustrating an all-solid-state battery according to embodiments of the present invention.

[0010] FIG. 3 is a cross-sectional view illustrating a battery cell according to embodiments of the present invention.

[0011] FIGS. 4A and 4B are perspective views illustrating a metal spring according to embodiments of the present invention.

[0012] Figures 5 to 10 are cross-sectional views showing all-solid-state batteries according to embodiments of the present invention.

[0013] Fig. 11 is a graph showing the usable temperature of a metal spring pad according to one embodiment of the present invention.

[0014] FIG. 12, FIG. 13a, and FIG. 13b are graphs showing the life characteristics of a metal spring pad according to one embodiment of the present invention.

[0015] 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.

[0016] 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. Also, in the drawings, the thickness of the components is exaggerated for the purpose of effectively explaining the technical contents. Parts designated by the same reference numbers throughout the specification represent the same components.

[0017] The embodiments described herein will be described with reference to cross-sectional views, plan views, and / or perspective views, which are ideal illustrations of the present invention. Although terms such as "first," "second," and "third" are used to describe various components in various embodiments of this specification, these components should not be limited by these terms. These terms are used merely to distinguish one component from another. The embodiments described and illustrated herein also include complementary embodiments.

[0018] The terminology used herein is for the purpose of describing embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise. As used herein, the words "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components.

[0019]

[0020] FIG. 1 is a plan view illustrating an all-solid-state battery according to embodiments of the present invention. FIG. 2 is a cross-sectional view taken along line A-A' of FIG. 1, illustrating an all-solid-state battery according to embodiments of the present invention.

[0021] Referring to FIGS. 1 and 2, the all-solid-state battery may include a first laminate (LAM1), a first pouch (PCH1), a first end plate (ENP1), a second end plate (ENP2), a first metal spring pad (MSP1), and a fastening portion (CPP).

[0022] The first laminate (LAM1) may include at least one first battery cell (CEL1) and at least one first elastic pad (EPD1). The first laminate (LAM1) may include a plurality of first battery cells (CEL1) and a plurality of first elastic pads (EPD1). The first laminate (LAM1) may be formed by alternately stacking the plurality of first battery cells (CEL1) and the plurality of first elastic pads (EPD1). For example, the first laminate (LAM1) may be formed by stacking the first battery cell (CEL1) on the first elastic pad (EPD1) and stacking the first elastic pad (EPD1) on the first battery cell (CEL1). However, the present invention is not limited to the described examples.

[0023] Each of the first elastic pads (EPD1) can relieve stress generated due to volume change of the first battery cell (CEL1) during charge and discharge. Each of the first elastic pads (EPD1) can be composed of elastically deformable members, and more specifically, can be composed of a material having a lower elastic modulus than that of the positive electrode current collector and the negative electrode current collector. Each of the first elastic pads (EPD1) can include an insulating material. For example, the material of the first elastic pad (EPD1) can include, but is not limited to, epoxy resin, acrylic resin, polyimide resin, polyester resin, polypropylene resin, polyamide resin, polystyrene resin, polyvinyl chloride resin, polycarbonate resin, fluororesin such as PTFE, silicone rubber, etc.

[0024] The first metal spring pad (MSP1) may be interposed between the first end plate (ENP1) and the second end plate (ENP2). For example, referring to FIG. 2, the first metal spring pad (MSP1) may be positioned between the first laminate (LAM1) and the first end plate (ENP1). Alternatively, the first metal spring pad (MSP1) may be positioned between the first laminate (LAM1) and the second end plate (ENP2).

[0025] The first metal spring pad (MSP1) may include a first metal spring (SPR1) and a first metal plate (PLT1).

[0026] The first metal spring (SPR1) may include a plurality of metal springs that are two-dimensionally arranged on the first metal plate (PLT1). For example, the plurality of metal springs may be arranged at regular intervals along a first direction (D1) and a second direction (D2) intersecting the first direction (D1) (see FIG. 1). That is, the plurality of metal springs may be arranged in a checkerboard pattern. The plurality of metal springs may be arranged closely together. For example, the distance between adjacent metal springs may be 0 mm to 3 mm. The first metal spring (SPR1) may be composed of a plurality of metal spring units (SPR1a, see FIGS. 4a and 4b), which will be described in detail in FIG. 4.

[0027] The first metal plate (PLT1) may include a plurality of metal plates. The first metal spring (SPR1) may be interposed between the plurality of metal plates. For example, the first metal spring (SPR1) may be interposed between the lower metal plate and the upper metal plate.

[0028] The first metal spring pad (MSP1) can provide elasticity. When charging and discharging the all-solid-state battery, the first metal spring pad (MSP1) can minimize changes in pressure within the first battery cell (CEL1).

[0029] The thickness of the first metal spring pad (MSP1) may be 3 mm to 30 mm, specifically 10 mm to 25 mm. If the thickness of the first metal spring pad (MSP1) is less than this, it may not provide elasticity to allow the first battery cell (CEL1) to sufficiently contract. If the thickness of the first metal spring pad (MSP1) is greater than this, the energy density of the first battery cell (CEL1) may decrease.

[0030] The area of ​​the first metal spring pad (MSP1) may be equal to or greater than the area of ​​the first laminate (LAM1).

[0031] The first metal spring pad (MSP1) can be used at temperatures from -50°C to 150°C. The first metal spring pad (MSP1) can perform its original function without any change in elasticity at the appropriate temperature of the battery.

[0032] The first metal spring pad (MSP1) can be used even at high temperatures. For example, the first metal spring pad (MSP1) may not rupture even when used at temperatures above 70°C.

[0033] The first metal spring pad (MSP1) can be used even at low temperatures. For example, the first metal spring pad (MSP1) may not harden even when used at temperatures below 20°C.

[0034] The first metal spring pad (MSP1) may be heat-dissipating. For example, the thermal conductivity of the first metal spring pad (MSP1) may be 0.01 W / mK to 30 W / mK.

[0035] The first metal spring pad (MSP1) may be non-combustible.

[0036] The first pouch (PCH1) can enclose the first laminate (LAM1). For example, the first laminate (LAM1) can be placed within the first pouch (PCH1) and sealed in a vacuum by the first pouch (PCH1). For example, referring to FIG. 2, the first pouch (PCH1) can enclose the first laminate (LAM1) and the first metal spring pad (MSP1) together.

[0037] The first end plate (ENP1) may be positioned above the first laminate (LAM1). The second end plate (ENP2) may be positioned below the first laminate (LAM1). The first and second end plates (ENP1, ENP2) may sandwich the first laminate (LAM1). The first and second end plates (ENP1, ENP2) may apply a constant pressure to the first laminate (LAM1) and suppress an increase in the internal resistance of the first laminate (LAM1).

[0038] The first and second end plates (ENP1, ENP2) may have a first metal spring pad (MSP1) interposed therebetween.

[0039] A coupling point (CPP) may be configured to couple the first and second end plates (ENP1, ENP2) to each other. The first and second end plates (ENP1, ENP2) may be fixed to each other by the coupling point (CPP).

[0040]

[0041] FIG. 3 is a cross-sectional view illustrating a first battery cell (CEL1) according to embodiments of the present invention.

[0042] Referring to FIG. 3, each of the first battery cells (CEL1) may include a positive electrode layer (100), a negative electrode layer (200) facing the positive electrode layer (100), and a solid electrolyte layer (300) disposed between the positive electrode layer (100) and the negative electrode layer (200). However, the present invention is not limited thereto, and the first battery cell (CEL1) may further include an additional functional layer, such as an adhesion enhancing layer, disposed between the positive electrode layer (100) and the solid electrolyte layer (300) or between the negative electrode layer (200) and the solid electrolyte layer (300).

[0043] The positive electrode layer (100) may include a positive electrode current collector (110) and a positive electrode active material layer (120) disposed on the positive electrode current collector (110). The positive electrode active material layer (120) may include a positive electrode active material, a solid electrolyte, a conductive material, and a binder.

[0044] The positive electrode current collector (110) can provide a reference surface on which the positive electrode active material layer (120) is arranged. The positive electrode current collector (110) can have a plate or foil shape. For example, the positive electrode current collector (110) can include 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.

[0045] Unlike the one illustrated in FIG. 3, in one embodiment of the present invention, the positive electrode current collector (110) may be omitted. Although not illustrated, a carbon layer having a thickness of 0.1 μm to 4 μm may be additionally disposed between the positive electrode current collector (110) and the positive electrode active material layer (120) to increase the bonding strength between the positive electrode current collector (110) and the positive electrode active material layer (120).

[0046] The cathode active material may be a material that can reversibly absorb and desorb lithium ions. For example, the cathode active material may include, but is not 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 thereof.

[0047] Lithium transition metal oxides include, for example, Li a A 1-b B b D2(0.90≤a≤1, 0≤b≤0.5), Li a E 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 Mn b B c D α(0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2), Li a Nor 1-b-c Mn 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 Nor b E c G d O2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1), Li a Nor b Co c Mn 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 NiG b O2(0.9≤a≤1, 0.001≤b≤0.1), Li a CoG b O2(0.90≤a≤1, 0.001≤b≤0.1), Li a MnG b O2(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-fIt may be a compound represented by any one of Fe2(PO4)3(0≤f≤2), LiFePO4. In these compounds, the capital letter “A” is Ni, Co, Mn, or a combination thereof, the capital letter “B” is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof, the capital letter “D” is O, F, S, P, or a combination thereof, the capital letter “E” is Co, Mn, or a combination thereof, the capital letter “F” is F, S, P, or a combination thereof, the capital letter “G” is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof, the capital letter “Q” is Ti, Mo, Mn, or a combination thereof, the capital letter “I” is Cr, V, Fe, Sc, Y, or a combination thereof, and the capital letter “J” is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0048] 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 Mnz O2(NCM) (0 <x<1,0<y<1, 0<z<1, x+y+z=1) 등의 삼원계 리튬전이금속산화물일 수 있다. 양극 활물질이 층상암염형 구조를 갖는 삼원계 리튬전이금속산화물을 포함하는 경우, 제1 전지셀(CEL1)의 에너지 밀도가 커지고 열안정성이 향상될 수 있다.

[0049] 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 for forming the coating layer may be selected within a range that does not adversely affect the physical properties of the positive electrode active material. The method for forming the coating layer may include, for example, a spray coating method or an immersion method.

[0050] When the positive electrode active material includes nickel (Ni) as a ternary lithium transition metal oxide such as NCA or NCM, for example, the capacity density of the first battery cell (CEL1) can be increased, thereby reducing metal dissolution of the positive electrode active material in a charged state. As a result, the cycle characteristics of the first battery cell (CEL1) in a charged state can be improved. Meanwhile, the “cycle characteristics” are characteristics indicating the degree to which the first battery cell (CEL1) is deteriorated due to charge / discharge of the first battery cell (CEL1). A first battery cell (CEL1) with high cycle characteristics may have a small degree of deterioration of the first battery cell (CEL1) due to charge / discharge, and a first battery cell (CEL1) with low cycle characteristics may have a large degree of deterioration of the first battery cell (CEL1) due to charge / discharge.

[0051] The shape of the positive electrode active material may include particle shapes such as a sphere or an ellipsoid, for example. The particle size and content of the positive electrode active material are not particularly limited.

[0052] The solid electrolyte may include a sulfide-based solid electrolyte having excellent lithium ion conductivity characteristics. Examples of the sulfide-based solid electrolyte include 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-Z. m S n (m, n are positive numbers, capital letter “Z” represents Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are positive numbers, capital letter “M” is one of P, Si, Ge, B, Al, Ga In), Li 7-x PS 6-x Clx (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 include at least one selected from (0≤x≤2).

[0053] 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 (0≤x≤2) may be an argyrodite-type compound including at least one selected from. In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I. 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.

[0054] The solid electrolyte included in the positive electrode active material layer (120) may have a smaller median particle size (D50) than the solid electrolyte included in the solid electrolyte layer (300). For example, the median particle size (D50) of the solid electrolyte included in the positive electrode active material layer (120) 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 (300). Meanwhile, the median particle size (D50) may be a median diameter measured using a laser particle size distribution meter.

[0055] The positive electrode active material layer (120) may include a conductive material. The conductive material may have conductivity without causing a chemical change in the first battery cell (CEL1), thereby increasing the conductivity of the positive electrode active material and the solid electrolyte. The conductive material may include a carbon-based material. The conductive material may include, for example, one or more selected from graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0056] The positive electrode active material layer (120) 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 (120) and improving bonding strength with the positive electrode current collector (110). For example, the binder may include polyvinylidene fluoride, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, or polymethyl methacrylate.

[0057] When the total amount of the positive electrode active material, the solid electrolyte, the conductive material, and the binder is 100 parts by weight, the positive electrode active material layer (120) may include 85 parts by weight to 92 parts by weight of the positive electrode active material. The positive electrode active material layer (120) may include 0.5 parts by weight to 1.5 parts by weight of the binder.

[0058] Within the positive electrode active material layer (120), the conductive material may be present in an amount of 1 to 50 parts by weight relative to 100 parts by weight of the solid electrolyte. If the conductive material is present in an amount less than 1 part by weight relative to 100 parts by weight of the solid electrolyte, the electrical conductivity of the positive electrode active material layer (120) may be reduced. If the conductive material is present in an amount greater than 50 parts by weight relative to 100 parts by weight of the solid electrolyte, the conductive material ratio may be excessively high, and thus a covering layer covering the surface of the solid electrolyte may not be properly formed.

[0059] According to embodiments, the positive electrode active material layer (120) may further include at least one additive selected from the group consisting of a filler, a coating agent, a dispersant, and an ion conductive auxiliary agent in addition to the above-described positive electrode active material, solid electrolyte, conductive agent, and binder.

[0060] The solid electrolyte layer (300) is disposed between the positive electrode layer (100) and the negative electrode layer (200) and may include a sulfide-based solid electrolyte having excellent lithium ion conductivity characteristics. The solid electrolyte included in the solid electrolyte layer (300) may be the same as or different from any one of the materials that may be included in the solid electrolyte included in the positive electrode active material layer (120) described above.

[0061] The solid electrolyte layer (300) of one embodiment 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.

[0062] 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(0≤x≤2) may be an argyrodite-type compound including at least one selected from. In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I. 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 is, for example, 15 GPa to 35 GPa.

[0063] The solid electrolyte layer (300) may further include a binder. The binder in the solid electrolyte layer (300) may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited thereto. The binder of the solid electrolyte layer (300) may be the same as or different from the binder included in the positive electrode active material layer (120) or the binder included in the negative electrode coating layer (220).

[0064] The negative electrode layer (200) may include a negative electrode current collector (210) and a negative electrode coating layer (220) on the negative electrode current collector (210). The negative electrode current collector (210) may provide a reference surface on which the negative electrode coating layer (220) is disposed. The negative electrode current collector (210) may include, for example, a material that does not react with lithium, i.e., does not form an alloy or a compound with lithium. For example, the negative electrode current collector (210) 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 (210) may be 1 μm to 20 μm, more specifically 5 μm to 15 μm, and more specifically 7 μm to 10 μm.

[0065] The negative electrode current collector (210) 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 (210) may have, for example, a plate shape or a foil shape. Meanwhile, in one embodiment, the negative electrode current collector (210) may be omitted.

[0066] The negative electrode coating layer (220) can allow lithium metal to grow between the first battery cell (CEL1) and the negative electrode current collector (210) when charging. The negative electrode coating layer (220) can act as a protective layer for the lithium metal and simultaneously suppress the precipitation and growth of lithium dendrites.

[0067] The cathode coating layer (220) may include a metal and carbon. For example, the cathode coating layer (220) 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 (220) 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 (220) may include a mixture of carbon black and silver (Ag).

[0068] The cathode coating layer (220) may further include additives other than metal and carbon. The cathode coating layer (220) may further include, for example, at least one additive selected from the group consisting of a binder, a filler, a coating agent, a dispersant, and an ion conductive additive.

[0069] The negative electrode coating layer (220) may have a smaller thickness than the positive electrode active material layer (120). The thickness of the negative electrode coating layer (220) may be, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the thickness of the positive electrode active material layer (120). The thickness of the negative electrode coating layer (220) may be, for example, 1 um to 20 um, 2 um to 10 um, or 3 um to 7 um. If the thickness of the negative electrode coating layer (220) is too thin, lithium dendrites formed between the negative electrode coating layer (220) and the negative electrode current collector (210) may cause the negative electrode coating layer (220) to collapse, thereby deteriorating the cycle characteristics of the first battery cell (CEL1). If the thickness of the cathode coating layer (220) increases excessively, the energy density of the first battery cell (CEL1) may decrease and the internal resistance of the first battery cell (CEL1) due to the cathode coating layer (220) may increase, thereby deteriorating the cycle characteristics of the first battery cell (CEL1).

[0070] Meanwhile, although not shown, a carbon layer may be further included to improve adhesion between the cathode coating layer (220) and the solid electrolyte layer (300).

[0071]

[0072] FIGS. 4A and 4B are perspective views illustrating a first metal spring (SPR1) according to embodiments of the present invention. FIG. 4A is a perspective view illustrating a first metal spring unit (SPR1a) constituting the first metal spring (SPR1) according to embodiments of the present invention.

[0073] The first metal spring (SPR1) of the 1 metal spring pad (MSP1) described in FIGS. 1 and 2 may include a plurality of first metal spring units (SPR1a).

[0074] The first metal spring unit (SPR1a) may be a rotating body having a central axis along the third direction (D3). In addition, the first metal spring unit (SPR1a) may have an inner diameter and an outer diameter larger than the inner diameter. That is, the first metal spring unit (SPR1a) may have a ring shape when viewed from a planar perspective.

[0075] Referring to FIG. 4A, in one embodiment of the present invention, the first metal spring unit (SPR1a) may have a height that varies in a third direction along the circumference. For example, the upper and lower surfaces of the first metal spring unit (SPR1a) may increase or decrease in height in the third direction (D3) along the circumference. For example, the first metal spring unit (SPR1a) may have a wave shape in which the height varies in the third direction along the circumference.

[0076] The diameter of the first metal spring unit (SPR1a) may be 5 mm to 50 mm based on the outer diameter.

[0077] Referring to FIG. 4b, the first metal spring (SPR1) may include a plurality of first metal spring units (SPR1a). The first metal spring (SPR1) may have a form in which the plurality of first metal spring units (SPR1a) are stacked in a third direction (D3). The plurality of stacked first metal spring units (SPR1a) may be connected to each other to form a single first metal spring (SPR1).

[0078] The first metal spring (SPR1) may include a coil spring, a leaf spring, a volute spring, a circular spring, a spiral spring, a disc spring, a washer spring, a wave spring, a snap spring, a torsion bar spring, etc., but is not limited to the described forms.

[0079] The material of the first metal spring (SPR1) may include at least one selected from the group consisting of stainless steel (steel use stainless; SUS) and hard drawn steel.

[0080]

[0081] Figures 5 to 9 are cross-sectional views illustrating all-solid-state batteries according to embodiments of the present invention. For convenience of explanation, the same details as those described with reference to Figure 2 will be omitted below, and differences will be described in detail.

[0082] Referring to FIG. 5, the all-solid-state battery may further include a second laminate (LAM2) on the first laminate (LAM1). A first spring pad (MSP1) may be interposed between the first laminate (LAM1) and the second laminate (LAM2). A first pouch (PCH1) may enclose the first laminate (LAM1), the second laminate (LAM2), and the first spring pad (MSP1) together.

[0083] The second laminate (LAM2) may include at least one second battery cell (CEL2) and at least one second elastic pad (EPD2). The second laminate (LAM2) may include a plurality of second battery cells (CEL2) and a plurality of second elastic pads (EPD2). The second laminate (LAM2) may be formed by alternately stacking the plurality of second battery cells (CEL2) and the plurality of second elastic pads (EPD2). For example, the second laminate (LAM2) may be formed by stacking the second battery cell (CEL2) on the second elastic pad (EPD2) and stacking the second elastic pad (EPD2) on the second battery cell (CEL2). However, the present invention is not limited to the described examples.

[0084] Each of the second battery cells (CEL2) may include a positive electrode layer, a negative electrode layer facing the positive electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer. However, without limitation thereto, the second battery cell (CEL2) may further include an additional functional layer, such as an adhesion enhancing layer, disposed between the positive electrode layer and the solid electrolyte layer or between the negative electrode layer and the solid electrolyte layer. The specific components of each of the second battery cells (CEL2) may be the same as or different from those of the first battery cells (CEL1).

[0085] Each of the second elastic pads (EPD2) may include an insulating material. For example, the material of the second elastic pad (EPD2) may include, but is not limited to, epoxy resin, acrylic resin, polyimide resin, polyester resin, polypropylene resin, polyamide resin, polystyrene resin, polyvinyl chloride resin, polycarbonate resin, fluororesin such as PTFE, silicone rubber, etc. The specific components of each of the second elastic pads (EPD2) may be the same as or different from those of the first elastic pads (EPD1).

[0086] Referring to FIG. 6, the all-solid-state battery may further include a second pouch (PCH2). A first metal spring pad (MSP1) may be interposed between the first pouch (PCH1) and the second pouch (PCH2).

[0087] The second pouch (PCH2) can selectively enclose only the second laminate (LAM2) excluding the first metal spring pad (MSP1). For example, the second laminate (LAM2) can be placed in the second pouch (PCH2) and sealed under vacuum.

[0088] Referring to FIG. 7, the all-solid-state battery may further include a second metal spring pad (MSP2). The second metal spring pad (MSP2) may be positioned on the first laminate (LAM1). The second metal spring pad (MSP2) may be spaced apart from the first metal spring pad (MSP1) in a vertical direction (i.e., a third direction (D3)). In other words, the first laminate (LAM1) may be positioned between the first metal spring pad (MSP1) and the second metal spring pad (MSP2). For example, the first metal spring pad (MSP1) may be interposed between the first laminate (LAM1) and the second end plate (EPD2), and the second metal spring pad (MSP2) may be interposed between the first laminate (LAM1) and the first end plate (EPD1). Alternatively, the first metal spring pad (MSP1) may be interposed between the first laminate (LAM1) and the first end plate (EPD1), and the second metal spring pad (MSP2) may be interposed between the first laminate (LAM1) and the second end plate (EPD2). The first pouch (PCH1) may wrap the first laminate (LAM1), the first metal spring pad (MSP1), and the second metal spring pad (MSP2) together.

[0089] The second metal spring pad (MSP2) may include a second metal spring (SPR2) and a first metal plate (PLT2).

[0090] The second metal spring (SPR2) may include a plurality of metal springs that are two-dimensionally arranged on the second metal plate (PLT2). For example, the plurality of metal springs may be arranged at regular intervals along a first direction (D1) and a second direction (D2) intersecting the first direction (D1). That is, the plurality of metal springs may be arranged in a checkerboard pattern. The plurality of metal springs may be arranged closely together. For example, the distance between adjacent metal springs may be 0 mm to 3 mm. The second metal spring (SPR2) may be composed of, for example, a plurality of metal spring units (SPR1a, see FIGS. 4A and 4B).

[0091] The second metal plate (PLT2) may include a plurality of metal plates, and the second metal spring (SPR2) may be interposed between the plurality of metal plates. For example, the second metal spring (SPR2) may be interposed between the lower metal plate and the upper metal plate.

[0092] Referring to FIG. 8, the first metal spring pad (MSP1) may be interposed between the first pouch (PCH1) and the second end plate (ENP2), and the second metal spring pad (MSP2) may be interposed between the first pouch (PCH1) and the first end plate (ENP1). Alternatively, the first metal spring pad (MSP1) may be interposed between the first pouch (PCH1) and the first end plate (ENP1), and the second metal spring pad (MSP2) may be interposed between the first pouch (PCH1) and the second end plate (ENP2). That is, the first and second metal spring pads (MSP1, MSP2) may be positioned outside the first pouch (PCH1).

[0093] Referring to FIGS. 9 and 10, the all-solid-state battery may further include a third laminate (LAM3) and a third pouch (PCH3). The third laminate (LAM3) may be interposed on the second laminate (LAM2). The second metal spring pad (MSP2) may be interposed between the first and second end plates (ENP1, ENP2). For example, the second metal spring pad (MSP2) may be positioned between the first pouch (PCH1) and the third pouch (PCH3), or between the second pouch (PCH2) and the third pouch (PCH3).

[0094] The third stack (LAM3) may include at least one third battery cell (CEL3) and at least one third elastic pad (EPD3). The third stack (LAM3) may include a plurality of third battery cells (CEL3) and a plurality of third elastic pads (EPD3). The third stack (LAM3) may be formed by alternately stacking the plurality of third battery cells (CEL3) and the plurality of third elastic pads (EPD3). For example, the third stack (LAM3) may be formed by stacking the third battery cell (CEL3) on the third elastic pad (EPD3) and stacking the third elastic pad (EPD3) on the third battery cell (CEL3). However, the present invention is not limited to the described examples.

[0095] Each of the third battery cells (CEL3) may include a positive electrode layer, a negative electrode layer facing the positive electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer. However, without limitation thereto, the third battery cell (CEL3) may further include an additional functional layer, such as an adhesion enhancing layer, disposed between the positive electrode layer and the solid electrolyte layer or between the negative electrode layer and the solid electrolyte layer. The specific components of each of the third battery cells (CEL3) may be the same as or different from those of the first battery cells (CEL1). The specific components of each of the third battery cells (CEL3) may be the same as or different from those of the second battery cells (CEL2).

[0096] Each of the third elastic pads (EPD3) may include an insulating material. For example, the material of the third elastic pad (EPD3) may include, but is not limited to, epoxy resin, acrylic resin, polyimide resin, polyester resin, polypropylene resin, polyamide resin, polystyrene resin, polyvinyl chloride resin, polycarbonate resin, fluororesin such as PTFE, silicone rubber, etc. The specific composition of each of the third elastic pads (EPD3) may be the same as or different from that of the first elastic pads (EPD1). The specific composition of each of the third elastic pads (EPD3) may be the same as or different from that of the second elastic pads (EPD2).

[0097] The third pouch (PCH3) may enclose the third laminate (LAM3). For example, the third laminate (LAM3) may be placed in the third pouch (PCH3) and sealed under vacuum.

[0098]

[0099] Hereinafter, the present invention will be described in more detail through examples. However, these examples are intended to exemplify the present invention and the scope of the present invention is not limited to these examples.

[0100]

[0101] Example

[0102] A metal spring pad comprising metal springs and metal plates was prepared. The metal springs were positioned between two metal plates and arranged in a checkerboard pattern on one metal plate. Adjacent metal springs were spaced at intervals of less than 2 mm. Each metal spring was composed of multiple metal spring units stacked together, and each metal spring unit was in the form of a wave spring. The diameter of the metal spring unit was approximately 7 mm. Each metal spring comprised stainless steel (SUS). The thickness of the metal spring pad ranged from 3 mm to 20 mm.

[0103]

[0104] Experimental Example 1: Investigation of the usable temperature of the pad

[0105] Using the pad of the example, the physical properties were investigated at different temperatures. The physical properties were investigated by pressing / releasing at a speed of 0.01 mm / s up to 7.5 MPa at a specific temperature.

[0106] The results of the example are shown in Fig. 11. Referring to Fig. 11, it was confirmed that the physical properties of the example were maintained even at high and low temperatures.

[0107]

[0108] Experimental Example 2: Investigation of the lifespan of the pad

[0109] The life of the pad of the example was investigated through a compression test. The compression test was conducted by measuring the force or pressure applied externally when the pad of the example was contracted. In the case of Fig. 12, the pad was first pressed at a speed of 0.01 mm / s to a specific pressure (MPa). Thereafter, the process of additionally pressing at a speed of 0.1 mm / s to y mm and releasing at a speed of 0.1 mm / s to y mm was repeated 1000 times. In the case of Fig. 13, the pad was first pressed at a speed of 0.01 mm / s to a specific pressure (MPa). Thereafter, the process of additionally pressing at a speed of 0.01 mm / s to b mm and releasing at a speed of 0.01 mm / s to b mm was repeated 10 times.

[0110] Figure 12 shows the results of measuring the external force applied after 1,000 repetitions of compression. Referring to Figure 12, the force of the embodiment was maintained without a significant decrease (approximately 95% decrease).

[0111] Referring to Fig. 13a, even after 10 repetitions of compression within a strain range of 30%, the embodiment did not undergo permanent deformation. Referring to Fig. 13b, even after repeated compression, the embodiment did not exhibit significant changes in response to externally applied force.

[0112] Through the above experimental results, it was confirmed that the lifespan of the example was excellent.

[0113]

[0114] While embodiments of the present invention have been described with reference to the attached drawings, the present invention may be implemented in other specific forms without altering the technical spirit or essential features thereof. Therefore, it should be understood that the embodiments described above are exemplary in all respects and are not limiting.

Claims

1. A first laminate comprising at least one first battery cell and at least one first elastic pad; A first pouch enclosing the first laminate; A first end plate on the first laminate; a second end plate below the first laminate, the first and second end plates sandwiching the first laminate; and A first metal spring pad interposed between the first and second end plates; All-solid-state battery.

2. In paragraph 1, Further comprising a second laminate on the first laminate, The second laminate comprises at least one second battery cell and at least one second elastic pad. All-solid-state battery.

3. In paragraph 2, The above first spring pad is interposed between the first laminate and the second laminate. All-solid-state battery.

4. In paragraph 2, Further comprising a second pouch surrounding the second laminate, The above first metal spring pad is interposed between the first pouch and the second pouch. All-solid-state battery.

5. In paragraph 1, Further comprising a second metal spring pad on the first laminate, The above two metal spring pads are spaced apart in the vertical direction from the above first metal spring pad. All-solid-state battery.

6. In paragraph 5, The first pouch wraps the first laminate, the first metal spring pad, and the second metal spring pad together. All-solid-state battery.

7. In paragraph 5, The above first metal spring pad is interposed between the first pouch and the second end plate, The second metal spring pad is interposed between the first pouch and the first end plate. All-solid-state battery.

8. In paragraph 2, A third laminate on the second laminate; A third pouch wrapping the third laminate; and Further comprising a second metal spring pad interposed between the first and second end plates; The third laminate comprises at least one third battery cell and at least one third elastic pad. All-solid-state battery.

9. In paragraph 1, The above first metal spring pad includes a first metal spring and a first metal plate. All-solid-state battery.

10. In paragraph 9, The above first metal spring includes a plurality of metal springs arranged two-dimensionally on the first metal plate. All-solid-state battery.

11. In paragraph 10, The above plurality of metal springs are arranged at regular intervals along a first direction and a second direction intersecting the first direction. All-solid-state battery.

12. In paragraph 9, The above first metal spring comprises at least one selected from the group consisting of a coil spring, a plate spring, a volute spring, a cylindrical spring, a spiral spring, a disc spring, a washer spring, a wave spring, a snap spring, and a torsion bar spring. All-solid-state battery.

13. In paragraph 9, The material of the first metal spring includes at least one selected from the group consisting of stainless steel and hard steel wire. All-solid-state battery.

14. In paragraph 1, The thickness of the above first metal spring pad is 3 mm to 30 mm. All-solid-state battery.

15. In paragraph 1, The above first metal spring pad can be used at -50℃ to 150℃. All-solid-state battery.

16. In paragraph 1, The thermal conductivity of the first metal spring pad is 0.01 W / mK to 15 W / mK. All-solid-state battery.

17. In paragraph 1, The above first metal spring pad is non-combustible, All-solid-state battery.

18. In paragraph 1, The above battery cell comprises a cathode layer, a cathode layer, and a solid electrolyte layer between the cathode layer and the anode layer. All-solid-state battery.

19. In paragraph 1, The above positive electrode layer includes a positive electrode current collector and a positive electrode active material layer, The above cathode layer comprises a cathode current collector and a cathode coating layer. All-solid-state battery.

20. In paragraph 1, The above elastic pad has a lower elasticity than each of the positive electrode layer and the negative electrode layer. All-solid-state battery.

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