Method for manufacturing sealed battery and sealed battery manufactured using same

Abstract

The present invention relates to a method for manufacturing a sealed battery and a sealed battery manufactured using same and, more specifically, to a method for manufacturing a sealed battery including a case body having formed therein an opening and an electrode assembly accommodated in the case body, and a cap plate sealing the opening of the case body, the method comprising: arranging the inner surface of the case body and the outer surface of the cap plate to face each other; and laser-welding the boundary between a first region of the upper surface of the case body and a second region of the upper surface of the cap plate, wherein the laser welding includes performing spatial modulation welding a plurality of times, and the spatial modulation welding includes irradiating a laser beam in a direction from the first region toward the second region, while moving from the first region to the boundary.

Description

Method for manufacturing a sealed battery and a sealed battery manufactured using the same

[0001] The present invention relates to a method for manufacturing a sealed battery and a sealed battery manufactured using the same, and more specifically, to a method for manufacturing a sealed battery using a space modulation welding method.

[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] Meanwhile, lithium-ion batteries currently on the market contain electrolytes containing flammable organic dispersions, which pose a risk of overheating and fire in the event of a short circuit. Considering these issues, all-solid-state batteries, which replace the electrolyte with a solid electrolyte, are being proposed. By eliminating flammable organic dispersions, all-solid-state batteries significantly reduce the risk of fire or explosion in the event of a short circuit. Therefore, these all-solid-state batteries can significantly improve safety compared to lithium-ion batteries that use electrolytes.

[0004] The problem to be solved by the present invention is to provide a method for manufacturing a sealed battery that can prevent diffuse reflection and scattering of a laser beam when laser welding the boundary between a cap plate and a case body in the manufacture of a sealed battery.

[0005] Another problem to be solved by the present invention is to provide a sealed battery manufactured using the above manufacturing method and having uniform welding.

[0006] A method for manufacturing a sealed battery according to the concept of the present invention may include manufacturing a sealed battery including a case body having an opening formed therein, an electrode assembly accommodated within the case body; and a cap plate sealing the opening of the case body. Specifically, the method may include: arranging an inner surface of the case body and an outer surface of the cap plate so that they face each other; and laser welding a boundary between a first region of an upper surface of the case body and a second region of an upper surface of the cap plate, wherein the laser welding includes performing spatial modulation welding multiple times, and the spatial modulation welding may include irradiating a laser beam while moving from the first region to the boundary in a direction from the first region toward the second region.

[0007] A method for manufacturing a sealed battery according to another concept of the present invention may include providing an electrode assembly, a case body having an opening formed therein, a cap plate having a through hole formed therein, a connecting member, and an insulating member; arranging an insulating member in the through hole of the cap plate; passing the connecting member through the cap plate through the through hole; electrically connecting the connecting member and the electrode assembly; accommodating the electrode assembly in the opening of the case body; arranging the inner surface of the case body in which the electrode assembly is accommodated and the outer surface of the cap plate so as to face each other; and laser welding a boundary between a first region of an upper surface of the case body and a second region of an upper surface of the cap plate. The laser welding may include: irradiating the first region with a laser beam to form a molten pool; and filling a gap located at the boundary with the molten pool.

[0008] According to another concept of the present invention, a sealed battery may include: an electrode assembly; a case body having an opening formed therein, the electrode assembly being accommodated within the case body; a cap plate having a through hole formed therein; a connecting member, the connecting member being electrically connected to the electrode assembly through the through hole of the cap plate; and a plurality of welding beads provided along a boundary between an upper surface of the cap plate and an upper surface of the case body. An interval between adjacent welding beads among the plurality of welding beads may be 0.05 mm to 0.2 mm.

[0009]

[0010] The method for manufacturing a sealed battery according to the present invention prevents the diffuse reflection and dispersion of the laser beam that may occur due to the steps and gaps between the cap plate and the case body by applying a spatial modulation method during laser beam irradiation. This enables uniform welding and prevents the occurrence of bullet marks on the insulating material placed on the cap plate.

[0011] The sealed battery according to the present invention is manufactured using the above manufacturing method, so that welding is performed uniformly, and thus the sealing effect is excellent.

[0012]

[0013] FIGS. 1A to 1C are cross-sectional views of an all-solid-state battery according to one embodiment of the present invention.

[0014] Figure 2 is a perspective view of a sealed battery according to one embodiment of the present invention.

[0015] Figure 3 is an exploded view of a sealed battery according to one embodiment of the present invention.

[0016] Figure 4 is a cross-sectional view of a sealed battery according to one embodiment of the present invention.

[0017] Figures 5a and 5b are cross-sectional views illustrating a method for manufacturing a sealed battery according to a comparative example.

[0018] FIGS. 6 to 11 are cross-sectional views illustrating a method for manufacturing a sealed battery according to embodiments of the present invention.

[0019] Figures 12 to 15 illustrate the shape of a welding bead formed on the upper surface of a sealed battery according to embodiments of the present invention.

[0020] Figure 16a is an image of the bead shape of a sealed battery manufactured by the method of Example 1 of the present invention. Figure 16b is an image of the bead shape of a sealed battery manufactured by the method of Comparative Example 1.

[0021] Figure 17a is an enlarged image of Figure 16a, and Figure 17b is an enlarged image of Figure 16b.

[0022] Figure 18 is an image of an insulating member area of ​​a sealed battery manufactured by the method of Comparative Example 1.

[0023]

[0024] 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.

[0025] In this specification, when a component is referred to as being on another component, it means that it can be formed directly on the other component, or a third component may be interposed between them. Furthermore, in the drawings, the thicknesses of the components are exaggerated for the sake of clarity. Parts designated by the same reference numerals throughout the specification represent the same components.

[0026] 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.

[0027] 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.

[0028]

[0029] Figure 1a is a cross-sectional view of an all-solid-state battery (10) according to one embodiment of the present invention.

[0030] Referring to FIG. 1A, an all-solid-state battery (10) according to one embodiment includes 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 all-solid-state battery (10) 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).

[0031] The positive electrode layer (100) of one embodiment includes 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.

[0032] The cathode current collector (110) can provide a reference surface on which the cathode active material layer (120) is arranged. The cathode current collector (110) can include a plate or foil including, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof.

[0033] Meanwhile, unlike that illustrated in FIG. 1A, in one embodiment of the present invention, the positive electrode 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 collector (110) and the positive electrode active material layer (120) to increase the bonding strength between the positive electrode collector (110) and the positive electrode active material layer (120).

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

[0035] Lithium transition metal oxides include, for example, Li a A 1-b B b D2(0.90≤a≤1, 0≤b≤0.5), Li a E 1-b B b O2-c D c (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05), LiE 2-b B b O 4-c D c (0≤b≤0.5, 0≤c≤0.05), Li a Ni 1-b-c Co b B c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Co b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Mr b B c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2), Li a Ni 1-b-c Mr b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni b HAVE BEEN c G d O2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1), Li a Ni b Co c Mr d GeO2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0.001≤e≤0.1), Li a 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), Lia Mn2GbO4(0.90≤a≤1, 0.001≤b≤0.1), QO2, QS2, LiQS2, V2O5, LiV2O5, LiIO2, LiNiVO4, Li 3-f J2(PO4)3(0≤f≤2), Li 3-f A compound represented by any one of Fe2(PO4)3(0≤f≤2), LiFePO4. In these compounds, 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.

[0036] The cathode active material may include, for example, a lithium salt of a transition metal oxide having a layered rock salt type structure among the lithium transition metal oxides described above. The "layered rock salt type structure" is, for example, a cubic rock salt type structure. <111> It is a structure in which oxygen atomic layers and metal atomic layers are alternately and regularly arranged in a direction, and thereby each atomic layer forms a two-dimensional plane. The "cubic rock salt structure" refers to the sodium chloride type (NaCl type) structure, which is a type of crystal structure, and specifically refers to a structure in which the face-centered cubic lattice (fcc) formed by each cation and anion is arranged with a displacement of half of the ridge of the unit lattice. Lithium transition metal oxides having this layered rock salt structure include, for example, LiNi x Co y Al z O2(NCA) or LiNi x Co y Mn z O2(NCM) (0 <x<1,0<y<1, 0<z<1, x+y+z=1) 등의 삼원계 리튬전이금속산화물일 수 있다. 양극활물질이 층상암염형 구조를 갖는 삼원계 리튬전이금속산화물을 포함하는 경우, 전고체 전지(10)의 에너지 밀도가 커지고 열안정성이 향상될 수 있다.

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

[0038] When the cathode active material contains nickel (Ni) as a ternary lithium transition metal oxide such as NCA or NCM, for example, the capacity density of the all-solid-state battery (10) can be increased, thereby reducing metal dissolution of the cathode active material in a charged state. As a result, the cycle characteristics of the all-solid-state battery (10) in a charged state are improved. Meanwhile, the “cycle characteristics” are characteristics indicating the degree to which the all-solid-state battery (10) is deteriorated due to charge / discharge of the all-solid-state battery (10). An all-solid-state battery (10) with high cycle characteristics may have a small degree of deterioration of the all-solid-state battery (10) due to charge / discharge, and an all-solid-state battery (10) with low cycle characteristics may have a large degree of deterioration of the all-solid-state battery (10) due to charge / discharge.

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

[0040] 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 Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I x It may include at least one selected from (0≤x≤2).

[0041] Sulfide-based solid electrolytes include, for example, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I x It may be an argyrodite-type compound including at least one selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0042] Alternatively, the sulfide-based solid electrolyte is Li 7-a M a PS 6-c X c It may be an argyrodite-type compound containing (0≤a≤2, (0≤c≤2)), where X may be F, Br, Cl, or a combination thereof. M is candium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof. Can be.

[0043] 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.

[0044] 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.

[0045] The cathode active material layer (120) may include a conductive material. The conductive material may have conductivity without causing chemical changes in the all-solid-state battery (10), thereby increasing the conductivity of the cathode 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.

[0046] 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). The binder may include, for example, polyvinylidene fluoride, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0047] Based on 100 parts by weight of the total of the positive electrode active material, the solid electrolyte, the conductive material, and the binder, the positive electrode active material layer (120) may include 85 parts by weight or more and 92 parts by weight or less of the positive electrode active material. Based on 100 parts by weight of the total of the positive electrode active material, the solid electrolyte, the conductive material, and the binder, the positive electrode active material layer (120) may include 0.5 parts by weight or more and 1.5 parts by weight or less of the binder.

[0048] Based on 100 parts by weight of the solid electrolyte, the positive electrode active material layer (120) may include 1 part by weight or more and 50 parts by weight or less of a conductive material. If the conductive material is included in the positive electrode active material layer (120) in an amount of less than 1 part by weight based on 100 parts by weight of the solid electrolyte, the proportion of the conductive material may decrease, thereby lowering the electrical conductivity of the positive electrode active material layer (120). If the conductive material is included in the positive electrode active material layer (120) in an amount of more than 50 parts by weight based on 100 parts by weight of the solid electrolyte, the proportion of the conductive material may be excessively high, so that a covering layer covering the surface of the solid electrolyte may not be properly formed.

[0049] The cathode active material layer (120) may further include additives such as fillers, coating agents, dispersants, and ion conductive aids in addition to the cathode active material, solid electrolyte, conductive agent, and binder described above.

[0050] The solid electrolyte layer (300) is disposed between the positive electrode layer (100) and the negative electrode layer (200) and includes 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.

[0051] 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.

[0052] Sulfide-based solid electrolytes include, for example, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I x It may be an argyrodite-type compound including at least one selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0053] Alternatively, the sulfide-based solid electrolyte is Li 7-a M a PS 6-c X cIt may be an argyrodite-type compound containing (0≤a≤2, (0≤c≤2)), where X may be F, Br, Cl, or a combination thereof. M is candium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof. Can be.

[0054] The density of the argyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. When the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state battery is reduced, and the defect of the solid electrolyte membrane being penetrated and short-circuited due to the formation of lithium dendrites can be prevented. The elastic modulus of the solid electrolyte is, for example, 15 GPa to 35 GPa.

[0055] The solid electrolyte layer (300) may further include a binder. The binder included 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 active material layer (220).

[0056] The negative electrode layer (200) includes a negative electrode current collector (210) and a negative electrode active material layer (220) disposed on the negative electrode current collector (210). The negative electrode active material layer (220) may include a negative electrode active material and a binder.

[0057] The negative electrode current collector (210) can provide a reference surface on which the negative electrode active material layer (220) is arranged. The negative electrode current collector (210) can include, for example, a material that does not react with lithium, i.e., does not form an alloy or compound with lithium. The material constituting the negative electrode current collector (210) is not necessarily limited to, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni), and any material that can be used as an electrode current collector can be used. The thickness of the negative electrode current collector can be 1 to 20 μm, for example, 5 to 15 μm, for example, 7 to 10 μm.

[0058] 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) is, for example, in the form of a plate or foil. Meanwhile, in one embodiment, the negative electrode current collector (210) may be omitted.

[0059] The negative electrode active material included in the negative electrode active material layer (220) may have a particle form. The median particle size average particle diameter (D50) of the negative electrode active material having a particle form may be, for example, 4 μm or less, 2 μm or less, 1 μm or less, or 900 nm or less. The median particle size average particle diameter (D50) of the negative electrode active material may be, for example, 10 nm to 4 μm, 10 nm to 2 μm, or 10 nm to 900 nm. When the negative electrode active material has a median particle size average diameter (D50) in this range, reversible absorption and / or desorption of lithium may be facilitated during charge and discharge. Meanwhile, the median particle size average diameter (D50) may be a median diameter measured using a laser particle size distribution meter.

[0060] The negative electrode active material may include, for example, at least one selected from a carbon-based negative electrode active material and a metal or metalloid negative electrode active material.

[0061] The carbon-based negative electrode active material may be amorphous carbon, in particular. Examples of amorphous carbon include, but are not limited to, carbon black (CB), acetylene black (AB), furnace black (FB), ketjen black (KB), and graphene. Amorphous carbon is carbon that has no crystallinity or very low crystallinity, and is distinguished from crystalline carbon or graphitic carbon.

[0062] The metal or metalloid negative electrode active material includes, but is not necessarily limited to, one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn), and may be a metal negative electrode active material or a metalloid negative electrode active material that forms an alloy or compound with lithium. On the other hand, nickel (Ni) does not form an alloy with lithium and therefore is not a metal negative electrode active material.

[0063] The negative electrode active material layer (220) includes one type of negative electrode active material among these negative electrode active materials, or includes a mixture of multiple different negative electrode active materials. For example, the negative electrode active material layer (220) may include only amorphous carbon, or may include one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn).

[0064] In one embodiment, the negative electrode active material layer (220) may include a mixture of amorphous carbon and one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The mixing ratio of the mixture of amorphous carbon and gold (Au), etc., may be, for example, 10:1 to 1:2, 5:1 to 1:1, or 4:1 to 2:1 by weight, but is not necessarily limited to this range and may be selected according to the required characteristics of the all-solid-state battery (10). When the negative electrode active material has this composition, the cycle characteristics of the all-solid-state battery (10) may be further improved.

[0065] The binder included in the negative electrode active material layer (220) may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., but is not necessarily limited thereto. The binder may include a single binder or a plurality of different binders.

[0066] Since the negative electrode active material layer (220) includes a binder, the negative electrode active material layer (220) can be stably formed on the negative electrode current collector (210). That is, the bonding strength between the negative electrode active material layer (220) and the negative electrode current collector (210) can be increased. In addition, cracking of the negative electrode active material layer (220) is suppressed despite changes in the volume and / or relative positions of the negative electrode active material layer (220) during the charge and discharge process. If the negative electrode active material layer (220) does not include a binder, the negative electrode active material layer (220) can be easily separated from the negative electrode current collector (210). As the negative electrode active material layer (220) is detached from the negative electrode current collector (210), the negative electrode current collector (210) can come into contact with the solid electrolyte layer at the exposed portion, thereby increasing the possibility of a short circuit occurring.

[0067] The negative electrode active material layer (220) is manufactured, for example, by providing a mixture in which the materials constituting the negative electrode active material layer (220) are dispersed onto the negative electrode current collector (210). Since a binder is included in the materials constituting the negative electrode active material layer (220), stable dispersion of the negative electrode active material in the mixture is possible. For example, when applying the mixture onto the negative electrode current collector (210) by screen printing, it is possible to suppress clogging of the screen (e.g., clogging by aggregates of the negative electrode active material) by the binder.

[0068] The negative electrode active material layer (220) may further include other additives in addition to the negative electrode active material and binder. The negative electrode active material layer (220) may further include, for example, fillers, coating agents, dispersants, ion conductive additives, etc.

[0069] The negative electrode active material layer (220) may have a smaller thickness than the positive electrode active material layer (120). The thickness of the negative electrode active material 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 active material 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 active material layer (220) is too thin, lithium dendrites formed between the negative electrode active material layer (220) and the negative electrode current collector (210) may collapse the negative electrode active material layer (220), thereby deteriorating the cycle characteristics of the all-solid-state battery (10). If the thickness of the negative electrode active material layer (220) increases excessively, the energy density of the all-solid-state battery (10) may decrease and the internal resistance of the all-solid-state battery (10) due to the negative electrode active material layer (220) may increase, thereby deteriorating the cycle characteristics of the all-solid-state battery (10).

[0070] If the thickness of the negative electrode active material layer (220) decreases, the charge capacity of the negative electrode active material layer (220) may also decrease, for example. The charge capacity of the negative electrode active material layer (220) is, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, 5% or less, or 2% or less than the charge capacity of the positive electrode active material layer (120). The charge capacity of the negative electrode active material layer (220) is, for example, 0.1% to 50%, 0.1% to 40%, 0.1% to 30%, 0.1% to 20%, 0.1% to 10%, 0.1% to 5%, or 0.1% to 2% than the charge capacity of the positive electrode active material layer (120). If the charge capacity of the negative electrode active material layer (220) is excessively small, the thickness of the negative electrode active material layer (220) becomes very thin, and the same defects as the defects described above that occur when the thickness of the negative electrode active material layer (220) becomes excessively thin may occur. If the charge capacity of the negative electrode active material layer (220) increases excessively, the same defects as the defects described above that occur when the thickness of the negative electrode active material layer (220) increases excessively may occur.

[0071] The charge capacity of the positive electrode active material layer (120) can be obtained by multiplying the charge capacity density (mAh / g) of the positive electrode active material by the mass of the positive electrode active material of the positive electrode active material layer (120). When the positive electrode active material layer (120) includes several types of positive electrode active materials, the [charge capacity density Х mass] value is calculated for each positive electrode active material, and the sum of these values ​​of the positive electrode active materials is the charge capacity of the positive electrode active material layer (120). The charge capacity of the negative electrode active material layer (220) can also be calculated in the same way. That is, the charge capacity of the negative electrode active material layer (220) is obtained by multiplying the charge capacity density (mAh / g) of the negative electrode active material by the mass of the negative electrode active material in the negative electrode active material layer (220). When the negative electrode active material layer (220) includes several types of negative electrode active materials, the [charge capacity density Х mass] value is calculated for each negative electrode active material, and the sum of these values ​​of the negative electrode active materials is the capacity of the negative electrode active material layer (220). Here, the charge capacity density of the positive electrode active material and the negative electrode active material may be an estimated capacity using an all-solid-state half-cell using lithium metal as a counter electrode. The charge capacity of the positive electrode active material layer (120) and the negative electrode active material layer (220) can be directly measured by measuring the charge capacity using the all-solid-state half-cell. The charge capacity density can be obtained by dividing the measured charge capacity by the mass of each active material. Meanwhile, in the present specification, the “charge capacity” of the positive electrode active material layer (120) and the negative electrode active material layer (220) means the initial charge capacity measured at the time of the first cycle charge.

[0072] Meanwhile, although not shown, a carbon layer may be further included to improve adhesion between the negative electrode active material layer (220) and the solid electrolyte layer (300).

[0073] Figures 1b and 1c are cross-sectional views of an all-solid-state battery (10) according to another embodiment of the present invention. Figures 1b and 1c illustrate an all-solid-state battery (10) including a different cathode layer (200) from the all-solid-state battery (10) illustrated in Figure 1a.

[0074] Referring to FIG. 1b, the negative electrode layer (200) of the all-solid-state battery (10) may further include an additional negative electrode active material layer (230) disposed between the negative electrode current collector (210) and the negative electrode active material layer (220). The additional negative electrode active material layer (230) may be a metal layer including lithium or a lithium alloy. The additional negative electrode active material layer (230) may function as, for example, a lithium reservoir. The lithium alloy may include, but is not limited to, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy, and the like, and any lithium alloy may be used. The additional negative electrode active material layer (230) may include one of these alloys, lithium, or multiple types of alloys.

[0075] The thickness of the additional negative electrode active material layer (230) is not particularly limited, but may be, for example, 1 μm to 1000 μm, 1 μm to 500 μm, 1 μm to 200 μm, 1 μm to 150 μm, 1 μm to 100 μm, or 1 μm to 50 μm. If the thickness of the additional negative electrode active material layer (230) is too thin, it is difficult for the additional negative electrode active material layer (230) to perform the role of a lithium reservoir. If the thickness of the additional negative electrode active material layer (230) is too thick, the mass and volume of the all-solid-state battery (10) may increase, and the cycle characteristics of the all-solid-state battery (10) may deteriorate. The additional negative electrode active material layer (230) may be, for example, a metal foil having a thickness within this range.

[0076] The additional negative electrode active material layer (230) may be disposed between the negative electrode current collector (210) and the negative electrode active material layer (220), for example, before assembling the all-solid-state battery (10). In one embodiment, the additional negative electrode active material layer (230) may be formed by deposition between the negative electrode current collector (210) and the negative electrode active material layer (220) by charging after assembling the all-solid-state battery (10).

[0077] When an additional negative electrode active material layer (230) is placed between the negative electrode current collector (210) and the negative electrode active material layer (220) prior to assembling the all-solid-state battery (10), the additional negative electrode active material layer (230) can function as a lithium reservoir. Accordingly, the cycle characteristics of the all-solid-state battery (10) including the additional negative electrode active material layer (230) can be further improved.

[0078] In the case where an additional negative electrode active material layer (230) is disposed by charging after assembling the all-solid-state battery (10), the all-solid-state battery (10) may be charged in excess of the charging capacity of the negative electrode active material layer (220), and lithium may be absorbed into the negative electrode active material layer (220) at the initial stage of charging. That is, the negative electrode active material included in the negative electrode active material layer (220) may form an alloy or compound with the lithium ions that have moved from the positive electrode layer (100), and thus lithium may be precipitated between the negative electrode active material layer (220) and the negative electrode current collector (210), and a metal layer corresponding to the additional negative electrode active material layer (230) may be formed by the precipitated lithium. The additional negative electrode active material layer (230) is a metal layer mainly composed of lithium (i.e., metallic lithium). During discharge, lithium in the negative electrode active material layer (220) and the additional negative electrode active material layer (230), i.e., the metal layer, can be ionized and move toward the positive electrode layer (100). Therefore, lithium can be used as the negative electrode active material in the all-solid-state battery (10). In addition, the negative electrode active material layer (220) is formed to cover the additional negative electrode active material layer (230), thereby acting as a protective layer for the additional negative electrode active material layer (230) and suppressing the precipitation and growth of lithium dendrites. Therefore, short-circuiting and capacity reduction of the all-solid-state battery (10) can be suppressed, and as a result, the cycle characteristics of the all-solid-state battery (10) can be improved.

[0079] Referring to FIG. 1c, the negative electrode layer (200) of the all-solid-state battery (10) may include a negative electrode current collector (210), a metal layer (231) disposed on the negative electrode current collector (210), and a negative electrode coating layer (221) disposed on the metal layer (231).

[0080] The metal layer (231) may be a metal thin film containing lithium or a lithium alloy. The lithium alloy may include, but is not limited to, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy, and the like, and any lithium alloy may be used. The metal layer (231) may contain one of these alloys or lithium. Alternatively, the metal layer (231) may contain various types of alloys.

[0081] The cathode coating layer (221) is disposed on the metal layer (231), and the cathode coating layer (221) is formed to cover the metal layer (231), thereby acting as a protective layer for the metal layer (231), and at the same time, may suppress the precipitation and growth of lithium dendrites in the metal layer (231) containing lithium or a lithium alloy.

[0082] The cathode coating layer (221) may include amorphous carbon. The cathode coating layer (221) may include, for example, at least one of carbon black, acetylene black, furnace black, ketjen black, and graphene. The cathode coating layer (221) may include a metal material together with the amorphous carbon described above. For example, the cathode coating layer (221) may include at least one of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). In one embodiment, the cathode coating layer (221) may include a mixture of carbon black and silver (Ag).

[0083]

[0084] Basic configuration of a sealed battery

[0085] Before explaining the manufacturing method of a sealed battery, the basic configuration of the sealed battery of the present invention will first be explained with reference to FIGS. 2 to 4. FIGS. 2 to 4 are a perspective view, an exploded view, and a cross-sectional view, respectively, for explaining a sealed battery according to an embodiment of the present invention.

[0086] Referring to FIGS. 2 to 4, a sealed battery according to embodiments of the present invention may include an electrode assembly (CEA), a case body (CBD) having an opening (OPP) formed therein, and a cap assembly (CAA). The cap assembly (CAA) may include a cap plate (CAP), a connecting member (COM), and an insulating member (ISM).

[0087] The electrode assembly (CEA) may include an all-solid-state battery (10) described with reference to FIGS. 1A to 1C. The connecting member (COM) may be configured to electrically connect the electrode assembly (CEA) to a connection target object. The electrode assembly (CEA) may be electrically connected to the connecting member (COM). In one embodiment, the connecting member (COM) may include a first connecting member (COM1) and a second connecting member (COM2). The electrode assembly (CEA) may include a positive terminal and a negative terminal. The positive terminal of the electrode assembly (CEA) may be electrically connected to the first connecting member (COM1), and the negative terminal of the electrode assembly (CEA) may be electrically connected to the second connecting member (COM2). The first and second connecting members (COM1, COM2) may electrically connect the electrode assembly (CEA) to the connection target object.

[0088] A case body (CBD) may have an opening (OPP) formed on one side. An electrode assembly (CEA) may be accommodated in the opening (OPP). The opening (OPP) may be sealed by a cap assembly (CAA). In one embodiment, an outer surface of a cap plate (CAP) constituting the cap assembly (CAA) may be arranged to face an inner surface of the case body (CBD). The opening (OPP) of the case body (CBD) may be sealed by welding a boundary area between an upper surface of the cap plate (CAP) and an upper surface of the case body (CBD). The cap plate (CAP) and the case body (CBD) may be welded to form a case (CAS) of a sealed battery.

[0089] The cap plate (CAP) may have a through hole formed therein through which a connecting member (COM) may pass. The connecting member (COM) may be inserted into the case body (CBD) through the through hole and electrically connected to the electrode assembly (CEA).

[0090] Each of the case body (CBD) and the cap plate (CAP) may be made of a metal material. For example, they may include aluminum (Al), iron (Fe), an aluminum alloy, or an iron alloy.

[0091] At least a portion of the insulating member (ISM) may be positioned on the cap plate (CAP). The insulating member (ISM) may be positioned so as to be positioned around a connecting member (COM) that penetrates the cap plate (CAP). In one embodiment, referring to FIG. 4, the insulating member (ISM) may be positioned around a through hole of the cap plate (CAP) without penetrating the cap plate (CAP). In another embodiment, although not illustrated, the insulating member (ISM) may be positioned so as to penetrate the cap plate (CAP) together with the connecting member (COM) and surround the connecting member (COM).

[0092] Method for manufacturing sealed batteries

[0093] FIG. 5a and FIG. 5b are reference drawings for explaining problems that occur when a laser beam is irradiated directly to the boundary between a cap plate (CAP) and a case body (CBD).

[0094] Referring to FIG. 5a, when a laser beam is directly irradiated on the boundary between the cap plate (CAP) and the case body (CBD), the laser beam may be reflected randomly due to the step difference between the cap plate (CAP) and the case body (CBD), causing a bullet mark to be generated on the insulating member (ISM).

[0095] Referring to Fig. 5b, when a laser beam is irradiated directly onto the boundary between the cap plate (CAP) and the case body (CBD), the laser beam may be scattered in the gap (GAP) of the boundary area between the cap plate (CAP) and the case body (CBD). This may cause a bullet mark to be formed on the insulating member (ISM), and a molten pool may be formed unevenly, which may cause a defect in the weld.

[0096] Hereinafter, a method for manufacturing a sealed battery according to embodiments of the present invention will be described in detail with reference to FIGS. 6 to 12.

[0097] FIGS. 6 and 12 are plan views illustrating a method for manufacturing a sealed battery according to one embodiment of the present invention. FIGS. 7 to 11 are cross-sectional views illustrating a method for manufacturing a sealed battery according to one embodiment of the present invention.

[0098] Referring to FIG. 6, a method for manufacturing a sealed battery according to one embodiment of the present invention may include: arranging an outer surface of a cap plate (CAP) to face an inner surface of a case body (CBD) in which an electrode assembly (CEA) is accommodated; and sealing the case body (CBD) and the cap plate (CAP) by laser welding.

[0099] A method for manufacturing a sealed battery according to one embodiment of the present invention may further include providing an electrode assembly (CEA), a case body (CBD) having an opening (OPP) formed therein, a cap plate (CAP), a connecting member (COM), and an insulating member (ISM); arranging the connecting member (COM) through a through hole of the cap plate (CAP); arranging an insulating member (ISM) around the connecting member (COM); electrically connecting the connecting member (COM) and the electrode assembly (CEA); and accommodating the electrode assembly (CEA) in the opening (OPP) of the case body (CBD). The above-described steps may be performed before arranging the side surface of the cap plate (CAP) so as to face the inner surface of the case body (CBD) in which the electrode assembly (CEA) is accommodated.

[0100] Each of the electrode assembly (CEA), the case body (CBD) having an opening (OPP), the cap plate (CAP), the connecting member (COM), and the insulating member (ISM) may have the same configuration as described with reference to FIGS. 2 to 4.

[0101] Referring again to FIG. 6, the upper surface of the case body (CBD) may include a first region (RG1). The upper surface of the cap plate (CAP) may include a second region (RG2). The second region (RG2) may be a peripheral region of the upper surface of the cap plate (CAP). The first region (RG1) and the second region (RG2) may be adjacent to each other. Laser welding the case body (CBD) and the cap plate (CAP) may include laser welding the boundary between the first region (RG1) and the second region (RG2).

[0102] Specifically, the laser welding may include irradiating a laser beam to a first region (RG1) to form a melt pool, and irradiating a laser beam to the melt pool or the boundary between the first and second regions (RG1, RG2). In one embodiment, the laser welding may be performed using a spatial modulation method. For example, the laser beam may be irradiated while moving from the first region (RG1) to the boundary between the first region (RG1) and the second region (RG2) in a direction from the first region (RG1) to the second region (RG2).

[0103] Hereinafter, the spatial modulation method will be described in more detail with reference to FIGS. 7 to 11. First, referring to FIGS. 7 to 9, the laser unit (LAU) can start irradiating a laser beam from the outside of the case body (CBD). In one embodiment, the laser unit (LAU) can irradiate a laser beam while moving from the outside of the case body (CBD) to the second region (RG2) of the cap plate (CAP). In one embodiment, the laser unit (LAU) can irradiate a laser beam while moving from the outside of the case body (CBD) to the boundary between the first region (RG1) and the second region (RG2). The laser beam irradiation can be performed continuously without interruption to the boundary between the first region (RG1) and the second region (RG2).

[0104] Through this, the first region (RG1) of the case body (CBD) can be melted before the laser beam reaches the second region (RG2), thereby eliminating the step between the cap plate (CAP) and the case body (CBD). In addition, some of the formed molten pool (MEP) can flow into the gap (GAP) between the case body (CBD) and the cap plate (CAP) to fill the gap, thereby preventing scattering.

[0105] Referring to FIGS. 10 and 11, after the boundary between the first region (RG1) and the second region (RG2) is laser-welded, the laser unit (LAU) on the first region (RG1) and the second region (RG2) can move to the outside of the case body (CBD) through the first region (RG1). In one embodiment, the laser beam irradiation can be performed continuously without interruption while the laser unit (LAU) moves to the outside of the case body (CBD) on the second region (RG2). In another embodiment, although not illustrated, the laser beam irradiation can be interrupted while the laser unit (LAU) moves to the outside of the case body (CBD) on the second region (RG2). The laser unit (LAU) that has moved to the outside of the case body (CBD) can move to weld an unwelded area of ​​the boundary between the first region (RG1) and the second region (RG2).

[0106] Referring back to FIG. 6, the welding of the case body (CABD) and the cap plate (CAP) can be sealed by laser welding the entire boundary between the first region (RG1) and the second region (RG2). To this end, the spatial modulation welding method described with reference to FIGS. 7 to 11 can be performed multiple times. For example, the laser welding can include first modulation welding in which a laser beam is irradiated from a first position (PO1) on the first region (RG1) to a second position (PO2) on the boundary between the first region (RG1) and the second region (RG2); and second modulation welding in which a laser beam is irradiated from a third position (PO3) on the first region (RG1) to a fourth position (PO4) on the boundary between the first region (RG1) and the second region (RG2). Before the second modulation welding, the laser unit (LAU) can move from the second position (PO2) to the third position (PO3). In one embodiment, the laser unit can move from a second position (PO2) to a first position (PO1) and then from the first position (PO1) to a third position (PO3). In one embodiment, the laser beam irradiation can be performed continuously without interruption while the laser unit (LAU) moves from the second position (PO2) to the third position (PO3).

[0107] In one embodiment, a ratio of the distance from the second position (PO2) to the fourth position (PO4) to the distance from the first position (PO1) to the third position (PO3) may be 0.8 to 1.2. For example, the distance from the first position (PO1) to the third position (PO3) may be substantially equal to the distance from the second position (PO2) to the fourth position (PO4). In one embodiment, the distance from the first position (PO1) to the third position (PO3) may be 0.05 mm to 0.2 mm.

[0108] By irradiating a laser beam from a first position (PO1) to a second position (PO2), a first welding bead can be formed from a first region (RG1) to a boundary between the first region (RG1) and the second region (RG2). In addition, by irradiating a laser beam from a third position (PO3) to a fourth position (PO4), a second welding bead can be formed from the first region (RG1) to a boundary between the first region (RG1) and the second region (RG2). In one embodiment, the distance from the first position (PO1) to the third position (PO3) can be substantially equal to the distance between the first welding bead and the second welding bead.

[0109] The laser welding may further include a third modulation welding in which a laser beam is irradiated from a fifth position (PO5) on the first region (RG1) to a sixth position (PO6) on the boundary between the first region (RG1) and the second region (RG2).

[0110] In this way, first to nth modulation welding (n is an integer greater than or equal to 10) can be performed along the boundary between the first region (RG1) and the second region (RG2), thereby forming a plurality of weld beads (WBD) including the first and second weld beads (see FIGS. 12 to 15).

[0111] By first irradiating the laser beam to the first region (RG1) and then irradiating the laser beam to the boundary between the first region (RG1) and the second region (RG2), dispersion and diffuse reflection of the laser beam can be prevented. In addition, a molten pool can be formed uniformly, and then the molten pool can be solidified to form a uniform weld bead. For example, the boundary of the formed weld beads can be distinct. In addition, the gap between adjacent weld beads can be formed relatively uniformly. In one embodiment, the gap between adjacent weld beads can be 0.05 mm to 0.2 mm.

[0112] The output of the laser beam can be appropriately selected depending on the materials of the case body (CBD) and cap plate (CAP). For example, it can be from 1.0 kW to 15 kW, but is not limited thereto.

[0113] The moving speed of the laser beam can be appropriately selected depending on the output of the laser beam. For example, it can be from 1 mm / sec to 500 mm / sec, but is not limited thereto.

[0114] FIGS. 12 to 15 are cross-sectional views illustrating a laser welding path and the shape of welding beads formed through the path according to embodiments of the present invention.

[0115] Referring to Fig. 12, a laser beam (LB) that is initiated from the outside of the case body (CBD) can move in a straight line. For example, the laser beam (LB) can sequentially move along paths 1 to 6. For example, the laser beam (LB) can perform a first modulation welding by moving through the first region to the boundary between the first region and the second region, and then moving again toward the outside of the case body (CBD). Then, the laser beam (LB) can move along the longitudinal direction of the boundary between the first region (RG1) and the second region (RG2). Then, the laser beam (LB) can perform a second modulation welding by moving through the first region again to the boundary between the first region and the second region, and then moving again toward the outside of the case body (CBD).

[0116] The weld beads (WBD) can be formed in a shape extending from the first region (RG1) to the boundary between the first region (RG1) and the second region (RG2). Specifically, when the laser beam (LB) is circular, a square weld bead (WBD) with rounded corners can be formed through the above welding. The weld bead (WBD) can include a plurality of weld beads (WBD). Adjacent weld beads (WBD) can overlap each other.

[0117] Referring to FIG. 13, a laser beam (LB) that is started to be irradiated from the outside of the case body (CBD) can move in a straight line. For example, the laser beam (LB) can move in paths 1 to 6. In one embodiment, the laser beam (LB) can be continuously irradiated without interruption in paths 1 to 6. In another embodiment, the laser beam (LB) may not be irradiated in a path moving from the second region (RG2) to the first region (RG1). For example, the laser beam (LB) may be irradiated in paths 1, 3, and 5, which are paths moving from the first region (RG1) to the second region (RG2), and the laser beam (LB) may not be irradiated in paths 2, 4, and 6, which are paths moving from the second region (RG2) to the first region (RG1).

[0118] The weld beads (WBD) can be formed in a shape extending from the first region (RG1) to the boundary between the first region (RG1) and the second region (RG2). Specifically, when the laser beam (LB) is circular, the welding as described above can form square weld beads (WBD) with rounded corners.

[0119] Referring to Fig. 14, a laser beam (LB) that is initiated from the outside of the case body (CBD) can rotate. For example, the laser beam (LB) can rotate counterclockwise. While rotating, the laser beam (LB) can move in the longitudinal direction of the boundary between the first region (RG1) and the second region (RG2). In one embodiment, the laser beam (LB) can be continuously irradiated without interruption. In another embodiment, the laser beam (LB) may not be irradiated along a path in which the laser beam (LB) moves from the second region (RG2) to the first region (RG1).

[0120] The weld beads (WBD) can be formed in a shape extending from the first region (RG1) to the boundary between the first region (RG1) and the second region (RG2). Specifically, when the laser beam (LB) is circular, weld beads (WBD) in an elliptical or truncated elliptical shape can be formed through the above welding.

[0121] According to embodiments of the present invention, a cap plate (CAP) and a case body (CBD) can seal a battery case (CAS) by performing laser welding using the method described above. FIG. 15 illustrates the shape of weld beads (WBD) after laser welding is completed using the method described with reference to FIG. 14.

[0122] The method for manufacturing a sealed battery according to embodiments of the present invention first forms a molten pool (MEP) by irradiating a laser beam on the upper surface of a case body (CBD), and then irradiates the laser beam on the boundary between a cap plate (CAP) and the case body (CBD), thereby preventing scattering and diffuse reflection of the laser beam. This prevents the occurrence of bullet marks on the insulating member (ISM) and defects in the weld.

[0123]

[0124] A sealed battery according to one embodiment of the present invention can be manufactured by the sealed battery manufacturing method described above.

[0125] The sealed battery configuration described above with reference to FIGS. 2 to 4 may be included. For example, the sealed battery of the present invention may include an electrode assembly (CEA), a case body (CBD) having an opening (OPP) formed therein, and a cap assembly (CAA). The cap assembly (CAA) may include a cap plate (CAP), a connecting member (COM), and an insulating member (ISM).

[0126] In one embodiment, a sealed battery may be arranged such that the inner surface of a case body (CBD) containing an electrode assembly (CEA) and a side surface of a cap plate (CAP) face each other. The upper surface of the case body (CBD) and the upper surface of the cap plate (CAP) may together form the upper surface of the sealed battery.

[0127] The upper surface of the sealed battery may include a plurality of weld beads (WBD). The spacing between adjacent weld beads (WBD) may be formed at a constant level. In one embodiment, the spacing between adjacent weld beads may be 0.05 mm to 0.2 mm.

[0128]

[0129] Hereinafter, examples and comparative examples of the present invention will be described. However, the following examples are merely examples of the present invention, and the present invention is not limited to the following examples.

[0130]

[0131] Example 1

[0132] An insulating member, an all-solid-state battery, an aluminum can (case body), and a cap plate were prepared.

[0133] An all-solid-state battery was housed in an aluminum can, and an insulating material was placed on the upper surface of the cap plate. The side surface of the cap plate was placed so that it faced the inner surface of the aluminum can. Laser welding was performed on the boundary between the upper surface of the aluminum can and the upper surface of the cap plate.

[0134] Laser welding was performed by spatially modulating welding, starting with laser beam irradiation from the outside of the aluminum can and moving the laser beam to the upper surface boundary area of ​​the aluminum can and the cap plate, as described with reference to FIGS. 6 to 11 and FIG. 15. The spatially modulated welding was repeatedly performed along the boundary between the aluminum can and the cap plate, thereby completely sealing the aluminum can and the cap plate.

[0135]

[0136] Comparative Example 1

[0137] The aluminum can and cap plate were completely sealed in the same manner as in the example except that laser welding was performed as follows.

[0138] Laser welding was performed by irradiating a laser beam along the boundary between the aluminum can and the cap plate without spatial modulation from the outside of the aluminum can to the upper boundary area of ​​the aluminum can and the cap plate.

[0139]

[0140] Bead shape

[0141] Fig. 16a is an image of a bead shape formed through the above Example 1, and Fig. 16b is an image of a bead shape formed through the above Comparative Example 1. Figs. 17a and 17b are enlarged views of Figs. 16a and 16b, respectively. Fig. 18 is an enlarged view of an insulating member of a sealed battery manufactured through Comparative Example 1.

[0142] Referring to FIGS. 16A and 17A, it can be seen that the beads formed according to Example 1 have distinct boundaries and that the distance between adjacent beads is about 0.1 mm. On the other hand, referring to FIGS. 16B and 17B, it can be seen that the beads formed according to Comparative Example 1 have unclear boundaries and that the distance between adjacent beads is so close that it is difficult to measure. Through this, it can be seen that when the space modulation welding of the present invention is not applied, a uniform molten pool is not formed, and thus the quality of the welding is significantly reduced. In addition, referring to FIG. 18, it can be seen that the sealed battery manufactured through Comparative Example 1 has a bullet mark on the insulating member.

Claims

1. A method for manufacturing a sealed battery, comprising: a case body having an opening formed therein; an electrode assembly housed within the case body; and a cap plate sealing the opening of the case body; Arranging the inner surface of the case body and the outer surface of the cap plate so that they face each other; and Including laser welding the boundary between the first area of ​​the upper surface of the case body and the second area of ​​the upper surface of the cap plate, The above laser welding includes performing spatial modulation welding multiple times, A method for manufacturing a sealed battery, wherein the above-mentioned space modulation welding includes irradiating a laser beam while moving from the first region to the boundary in a direction from the first region toward the second region.

2. In paragraph 1, A method for manufacturing a sealed battery, wherein the above-mentioned space modulation welding further includes forming a molten pool by irradiating the laser beam to the first area.

3. In paragraph 1, The above laser welding: A first modulation welding process that irradiates a laser beam from a first position on the first area to a second position on the boundary; and A method for manufacturing a sealed battery, comprising a second modulation welding that irradiates a laser beam from a third position on the first region to a fourth position on the boundary.

4. In paragraph 3, A method for manufacturing a sealed battery, wherein the distance from the first position to the third position is 0.05 mm to 0.2 mm.

5. In paragraph 1, A method for manufacturing a sealed battery, wherein welding beads are formed along the above boundary.

6. In paragraph 5, A method for manufacturing a sealed battery, wherein each of the above welding beads is in the shape of an oval, a truncated oval or a square with rounded corners.

7. In paragraph 5, A method for manufacturing a sealed battery, wherein the gap between adjacent welding beads among the above welding beads is 0.05 mm to 0.2 mm.

8. In paragraph 1, The above laser welding: A method for manufacturing a sealed battery, which is performed by irradiating a laser beam in a direction perpendicular to the upper surface of the cap plate and the case body.

9. In paragraph 1, A method for manufacturing a sealed battery, wherein an insulating member is arranged on the upper surface of the cap plate.

10. In paragraph 1, The above electrode assembly: Comprising at least one all-solid-state battery, A method for manufacturing a sealed battery, wherein the all-solid-state battery comprises a cathode layer; a solid electrolyte layer on the cathode layer; and a cathode layer on the solid electrolyte layer.

11. Providing an electrode assembly, a case body having an opening formed therein, a cap plate having a through hole formed therein, a connecting member, and an insulating member; Placing an insulating member in the through hole of the cap plate; Penetrating the connecting member into the cap plate through the through hole; Electrically connecting the connecting member and the electrode assembly; Accommodating an electrode assembly in an opening of the case body; Positioning the inner surface of the case body containing the electrode assembly and the outer surface of the cap plate so that they face each other; and Including laser welding the boundary between the first area of ​​the upper surface of the case body and the second area of ​​the upper surface of the cap plate, The above laser welding: Forming a molten pool by irradiating a laser beam to the first region; and A method for manufacturing a sealed battery, comprising filling a gap located at the boundary with the molten pool.

12. In paragraph 11, The above laser welding: A first modulation welding process that irradiates a laser beam from a first position on the first area to a second position on the boundary; and A method for manufacturing a sealed battery, comprising a second modulation welding that irradiates a laser beam from a third position on the first region to a fourth position on the boundary.

13. In paragraph 11, A method for manufacturing a sealed battery, wherein welding beads are formed along the above boundary.

14. In paragraph 13, A method for manufacturing a sealed battery, wherein each of the above welding beads is in the shape of an oval, a truncated oval or a square with rounded corners.

15. In paragraph 13, A method for manufacturing a sealed battery, wherein the gap between adjacent welding beads among the above welding beads is 0.05 mm to 0.2 mm.

16. In paragraph 11, The above electrode assembly: Comprising at least one all-solid-state battery, A method for manufacturing a sealed battery, wherein the all-solid-state battery comprises a cathode layer; a solid electrolyte layer on the cathode layer; and a cathode layer on the solid electrolyte layer.

17. Electrode assembly; A case body having an opening formed therein, wherein the electrode assembly is accommodated within the case body; A cap plate with a through hole formed therein; a connecting member, said connecting member being electrically connected to said electrode assembly through a through hole of said cap plate; and Including a plurality of weld beads provided along the boundary between the upper surface of the cap plate and the upper surface of the case body, A sealed battery, wherein the gap between adjacent welding beads among the plurality of welding beads is 0.05 mm to 0.2 mm.

18. In paragraph 17, A sealed battery further comprising an insulating member, wherein the insulating member is disposed on the upper surface of the cap plate.

19. In paragraph 17, The shape of the above welding beads is an oval, a truncated oval or a square shape with rounded corners, a sealed battery.

20. In paragraph 17, The above electrode assembly: Comprising at least one all-solid-state battery, The above all-solid-state battery is a sealed battery comprising a cathode layer; a solid electrolyte layer on the cathode layer; and a cathode layer on the solid electrolyte layer.

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