Manufacturing method for all-solid-state batteries

Abstract

A method for manufacturing an all-solid-state battery is disclosed, which can suppress a short circuit phenomenon that occurs at the side portion during battery operation by isostatically pressing each unit cell and then stacking them. The method for manufacturing the all-solid-state battery includes the steps of: a) manufacturing a monocell or bicell by sequentially stacking a solid electrolyte and a positive electrode on one or both sides of a negative electrode; b) isostatically pressing the manufactured monocell or bicell; and c) stacking two or more of the isostatically pressed monocells or bicells, interposing a positive electrode current collector between one cell and the other cell, and bringing both sides of the interposed positive electrode current collector into contact with the positive electrode.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0132195 dated October 14, 2022, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a method for manufacturing an all-solid-state battery, and more particularly, to a method for manufacturing an all-solid-state battery that can suppress a short circuit phenomenon that occurs at a side portion during battery operation by isostatically pressing each unit cell and then stacking the unit cells. [Background technology]

[0003] As technological development and demand for mobile devices and automobiles has explosively increased, more and more research has been conducted on secondary batteries having high energy density, discharge voltage, and excellent output stability. Examples of such secondary batteries include lithium-based secondary batteries such as lithium-sulfur batteries, lithium-ion batteries, and lithium-ion polymer batteries. In addition, such secondary batteries can be classified into cylindrical, rectangular, pouch, and other types depending on their shapes, and among them, interest in and demand for pouch-type battery cells is gradually increasing. Pouch-type battery cells can be stacked with a high degree of integration, have a high energy density per weight, are inexpensive, and are easily deformable. Therefore, pouch-type battery cells can be manufactured in shapes and sizes applicable to various mobile devices and automobiles.

[0004] Such a pouch-type battery cell generally has a structure in which a large number of unit cells, each including a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes, are stacked (i.e., an electrode assembly or stack cell). After the electrode assembly is housed in a battery case, an electrolyte solution is injected or a solid electrolyte is provided in the electrode assembly from the beginning to produce a product (i.e., an all-solid-state battery).

[0005] Among these, all-solid-state batteries are superior in terms of safety compared to other types of secondary batteries, and are attracting attention especially in the fields of electric vehicles and mobile devices. In other words, all-solid-state batteries are batteries in which the electrolyte used in normal lithium secondary batteries is replaced from liquid to solid, which significantly improves safety by eliminating the use of flammable solvents and completely eliminating the risk of fire or explosion caused by the decomposition reaction of conventional electrolytes. In addition, all-solid-state batteries have the advantage of being able to dramatically improve the energy density relative to the mass and volume of the battery, since Li metal or Li alloy can be used as the anode material.

[0006] In the manufacturing process of such solid-state batteries, a warm isostatic pressing (WIP) process is generally used to bond the interface between the electrode and solid electrolyte. If the interface between the electrode and solid electrolyte is not properly bonded and the interface between the electrode and solid electrolyte is not properly formed, it is difficult for lithium (Li) ions to move, making it impossible for the battery to operate.

[0007] FIG. 1 is a schematic cross-sectional side view showing the electrode lamination form of a conventional all-solid-state battery. Conventional all-solid-state batteries generally have a structure in which a positive electrode (20, where 20a is a positive electrode current collector) having a length shorter than that of the negative electrode (10) is located between the negative electrodes (10, where 10a is a negative electrode current collector) as shown in FIG. 1, and a solid electrolyte (30) is interposed between each of the negative electrode (10) and the positive electrode (20). In addition, in such a conventional all-solid-state battery, for example, after the negative electrode (10), the solid electrolyte (30), the positive electrode (20), the solid electrolyte (30), and the negative electrode (10) are sequentially laminated, isostatic pressing must be performed in order to bond the electrodes and the solid electrolyte at the interface when the lamination is completed.

[0008] However, because a typical solid-state battery has a structure as shown in Figure 1 (i.e., a positive electrode is interposed between negative electrodes, and the length of the positive electrode is shorter than the length of both negative electrodes), when isostatic pressure is applied to the top and bottom at the same time, both ends (or side parts) of the upper and lower negative electrodes are bent. During this process, cracks are likely to occur in the solid electrolyte layer and the negative electrode layer, and since appropriate pressure cannot be applied to these parts while the battery is running, this creates conditions that make it easy for lithium dendrites to grow, resulting in a short circuit.

[0009] In other words, in conventional solid-state batteries, isostatic pressing must be performed for interfacial bonding between the electrodes and solid electrolyte after lamination is complete, and at this time, since the positive electrode is interposed between the negative electrodes and the length of the positive electrode is shorter than the length of both negative electrodes, a short circuit is inevitably generated between the end of the negative electrode and the end side of the opposing positive electrode during operation. Therefore, it is necessary to find a method to eliminate the possibility of a short circuit occurring during battery operation while performing isostatic pressing for interfacial bonding between the electrodes and solid electrolyte. Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, an object of the present invention is to provide a method for manufacturing an all-solid-state battery that can suppress the short circuit phenomenon that occurs at the side portions during battery operation by isostatically pressing each unit cell and then stacking them. [Means for solving the problem]

[0011] In order to achieve the above object, the present invention provides a method for producing an all-solid-state battery, comprising: a) a step of producing a monocell or a bicell by sequentially stacking a solid electrolyte and a positive electrode on one or both sides of a negative electrode; b) a step of isostatically pressing the produced monocell or bicell; and c) a step of stacking two or more of the isostatically pressed monocells or bicells, in which a positive electrode current collector is interposed between one cell and another cell, and both sides of the interposed positive electrode current collector are brought into contact with the positive electrode, respectively. Effect of the Invention

[0012] According to the manufacturing method of the all-solid-state battery of the present invention, each unit cell is isostatically pressed and then stacked, so that isostatic pressing is not necessary when stacking is completed. This has the advantage of being able to suppress a short circuit phenomenon that occurs on the side surface during battery operation. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic side cross-sectional view showing an electrode lamination configuration of a typical all-solid-state battery. [Diagram 2] FIG. 2 is a schematic side cross-sectional view showing how two isostatically pressed mono-cells are stacked with a positive electrode current collector interposed therebetween in an all-solid-state battery according to one embodiment of the present invention. [Diagram 3] FIG. 11 is a schematic side cross-sectional view showing a state in which a number of isostatically pressed bi-cells are stacked with positive electrode current collectors interposed therebetween in an all-solid-state battery according to another embodiment of the present invention. [Figure 4] 4 is a graph comparing life characteristics and capacity retention rates of secondary batteries manufactured according to an embodiment of the present invention and a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will now be described in detail with reference to the accompanying drawings.

[0015] FIG. 2 is a schematic side cross-sectional view showing how two isostatically pressed mono-cells are stacked with a positive electrode current collector interposed therebetween in an all-solid-state battery according to one embodiment of the present invention, and FIG. 3 is a schematic side cross-sectional view showing how a large number of isostatically pressed bi-cells are stacked with a positive electrode current collector interposed therebetween in an all-solid-state battery according to another embodiment of the present invention.

[0016] 2 and 3, the method for manufacturing an all-solid-state battery according to the present invention includes the steps of: a) manufacturing a monocell (1000) or a bicell (2000) by sequentially stacking a solid electrolyte (300) and a positive electrode (200) on one or both sides of a negative electrode (100); b) isostatically pressing the manufactured monocell (1000) or bicell (2000); and c) stacking two or more of the isostatically pressed monocells (1000) or bicells (2000) by interposing a positive electrode current collector (220) between one cell and another cell, and contacting both sides of the interposed positive electrode current collector (220) with the positive electrode (200), respectively.

[0017] All-solid-state batteries are superior to other types of secondary batteries in terms of safety, and are especially in the spotlight in the fields of electric vehicles and mobile devices. In other words, all-solid-state batteries are batteries in which the electrolyte used in conventional lithium secondary batteries is replaced from liquid to solid, which significantly improves safety by eliminating the use of flammable solvents and eliminating the risk of fire or explosion caused by the decomposition reaction of conventional electrolytes. In addition, all-solid-state batteries have the advantage of being able to dramatically improve the energy density relative to the mass and volume of the battery, as they can use Li metal or Li alloy as the anode material. In the manufacturing process of such all-solid-state batteries, a warm isostatic pressing (WIP) process is generally used to bond the interface between the electrode and solid electrolyte. If the interface between the electrode and solid electrolyte is not properly bonded and the interface between the electrode and solid electrolyte is not properly formed, it is difficult for lithium (Li) ions to move, making it impossible for the battery to operate.

[0018] Meanwhile, in a typical solid-state battery, a positive electrode (20, where 20a is a positive electrode current collector) that is shorter than the negative electrode (10) is placed between negative electrodes (10, where 10a is a negative electrode current collector) as shown in Figure 1. This is to prevent the problem of lithium (Li) being deposited at the sliding portion due to the difference in contact area between the positive and negative electrodes caused by the electrode sliding phenomenon, and this lithium deposition problem can cause a decrease in the battery life and even cause explosions and fires.

[0019] A typical all-solid-state battery has a structure in which a solid electrolyte (30) is interposed between each of the negative electrode (10) and the positive electrode (20). In addition, in such a typical all-solid-state battery, for example, the negative electrode (10), the solid electrolyte (30), the positive electrode (20), the solid electrolyte (30), and the negative electrode (10) are sequentially stacked, and then isostatic pressing must be performed in order to bond the interface between the electrodes and the solid electrolyte when the stacking is completed. However, since a typical all-solid-state battery has a structure as shown in FIG. 1 (i.e., a structure in which a positive electrode is interposed between negative electrodes and the length of the positive electrode is shorter than the length of both negative electrodes), when isostatic pressing is performed in which the same pressure is applied simultaneously to the upper and lower parts, both ends (or side parts) of the upper and lower negative electrodes are bent. During this process, cracks are likely to occur in the solid electrolyte layer and the negative electrode layer, and since appropriate pressure cannot be applied to these parts while the battery is running, this creates conditions that favor the growth of lithium dendrites, resulting in a short circuit.

[0020] That is, in conventional all-solid-state batteries, isostatic pressing must be performed for interfacial bonding between the electrodes and solid electrolyte after stacking is complete, and at this time, a positive electrode is interposed between the negative electrodes, and at the same time, the length of the positive electrode is shorter than the length of both negative electrodes, so a short circuit is inevitably generated between the end of the negative electrode and the side of the end of the positive electrode facing it during operation. However, the applicant has invented a method in which each unit cell (mono-cell or bi-cell) is isostatically pressed first and then stacked, in which case isostatic pressing is not required after stacking is complete, and therefore it is possible to suppress the short circuit that occurs at the side during battery operation.

[0021] In order to manufacture the all-solid-state battery according to the present invention, a monocell (1000) or a bicell (2000) must first be manufactured by sequentially stacking a solid electrolyte (300) and a positive electrode (or a positive electrode not including a current collector or a free-standing positive electrode, 200) on one or both sides of a negative electrode (100) (step a). This is a prerequisite process for performing isostatic pressing under conditions where there is absolutely no risk of short-circuiting between the positive and negative electrodes. In the case of a monocell (1000), it contains only one negative electrode (100) and one positive electrode (200), and isostatic pressing is performed with the longest negative electrode (100) positioned at the bottom, so there is no room for short-circuiting between the positive and negative electrodes even when they are electrically connected. In the case of the bicell (2000), the anode (100) is formed as a single layer with the anode active material layer (100b) on either side of the anode current collector (100a), and the cathode (200) is located on either side of the anode, so that even in this case, there is no room for a short circuit between the cathode and anode, even if they are electrically connected. Meanwhile, the cathode (200) included in the monocell (1000) and the cathode (200) included in the bicell (2000) must both be free-standing cathodes that do not include a cathode current collector.

[0022] Here, the structures of the monocell (1000) and the bicell (2000) will be described. The monocell (1000) has a structure in which a solid electrolyte (300) and a positive electrode (200) not including a current collector are sequentially stacked on one side of a negative electrode (100) as shown in Fig. 2. More specifically, the monocell (1000) has a structure in which a solid electrolyte (300) and a positive electrode (200) not including a current collector are sequentially stacked on one side of a negative electrode active material layer (100b) as shown in Fig. 2, and a negative electrode current collector (100a) may be attached to the other side of the negative electrode active material layer (100b). That is, the negative electrode (100) of the monocell (1000) includes a negative electrode active material layer (100b); and a negative electrode current collector (100a); attached to one side of the negative electrode active material layer (100b), and has a structure in which a solid electrolyte (300) and a positive electrode (200) are sequentially laminated on the other side of the negative electrode active material layer (100b).

[0023] As shown in FIG. 3, the bicell (2000) has a structure in which a solid electrolyte (300) and a positive electrode (200) not including a current collector are sequentially stacked on each of both sides of a negative electrode (100). More specifically, as shown in FIG. 3, the bicell (2000) has a structure in which a solid electrolyte (300) and a positive electrode (200) not including a current collector are sequentially stacked on each of negative electrode active material layers (100b) located on both sides of a negative electrode current collector (100a) so as to face each other. That is, the negative electrode (100) of the bicell (2000) includes a negative electrode current collector (100a); and negative electrode active material layers (100b); attached to both sides of the negative electrode current collector (100a), and has a structure in which a solid electrolyte (300) and a positive electrode (200) are sequentially stacked on each of the negative electrode active material layers (100b).

[0024] In addition, in both the monocell (1000) and the bicell (2000), it is preferable that the length of the negative electrode (100) is longer than the length of the positive electrode (200) based on the vertical cross section, as shown in Figures 2 and 3. This is to prevent the problem of lithium deposition at the sliding part due to the difference in contact area between the positive electrode and the negative electrode caused by the electrode sliding phenomenon, and this lithium deposition problem may cause a decrease in the battery life and even cause an explosion and a fire accident. Meanwhile, although the above description is based on Figures 2 and 3, it can be said that the monocell and the bicell can be modified into various structures and shapes as long as the object of the present invention can be achieved.

[0025] As described above, after the monocell (1000) or bicell (2000) is manufactured by sequentially stacking the solid electrolyte (300) and the positive electrode (200) not including a current collector on one or both sides of the negative electrode (100), the monocell (1000) or bicell (2000) manufactured is subjected to isostatic pressing (step b). This is a process for interfacial bonding between the electrode and the solid electrolyte, and as described above, the isostatic pressing is performed under conditions where there is no risk of short circuiting between the positive and negative electrodes. In the case of the monocell (1000), the isostatic pressing is performed in a simplified state where the positive electrode (200) is located on top of the negative electrode (100), so that sufficient pressure can be applied and there is no room for short circuiting between the positive and negative electrodes. In the case of the bicell (2000), the negative electrode (100) is also composed of a single layer with the negative electrode active material layer (100b) located on both sides of the negative electrode current collector (100a), and the positive electrode (200) is located on both sides of the negative electrode (100). Therefore, even in this case, the negative electrode is not bent even when isostatic pressure is applied, and there is no room for a short circuit between the positive and negative electrodes to occur.

[0026] The isostatic pressing may be any one selected from the group consisting of warm isostatic pressing (WIP), hot isostatic pressing (HIP) and cold isostatic pressing (CIP). It may be preferable that the isostatic pressing is performed at a temperature within an appropriate range where the interfacial contact between the electrodes is good due to the molding of the solid electrolyte and the electrode constituent materials are thermally stable. For example, the warm isostatic pressing (WIP) may be performed at 45 to 100°C.

[0027] In order to stack the isostatically pressed monocells (1000) or bicells (2000) as in the next step, two or more monocells (1000) or bicells (2000) must be prepared in an isostatically pressed state. That is, when stacking the monocells (1000) as unit cells, as shown in FIG. 2, two monocells (1000) must be prepared in an isostatically pressed state. Also, when stacking the bicells (2000) as unit cells, each of the bicells (2000) must be prepared in an isostatically pressed state in a number that matches the size of the intended all-solid-state battery. That is, when stacking the bicells (2000) as unit cells, there is no particular limit to the number of bicells (2000) to be isostatically pressed. In FIG. 3, a total of three bicells (2000) are stacked, so in this case, three isostatically pressed bicells (2000) must be prepared. However, it should be noted that FIG. 3 is only one embodiment.

[0028] Finally, after isostatically pressing the monocell (1000) or bicell (2000) as described above, two or more of the isostatically pressed monocells (1000) or bicells (2000) are stacked, with a positive electrode current collector (220) interposed between one cell and another, and both sides of the interposed positive electrode current collector (220) are brought into contact with the positive electrode (200) (not including the current collector) (step c).

[0029] Specifically, when the monocells (1000) are stacked as unit cells, as shown in Fig. 2, a positive electrode current collector (220) is stacked on one monocell (1000), and then the remaining monocell (1000) is stacked to complete the production of an all-solid-state battery (the step of housing the battery inside a storage case such as a pouch may be performed separately). At this time, the two monocells (1000) are stacked with the "positive electrode (200) not including a current collector" contained therein facing each other, and both sides of the positive electrode current collector (220) interposed between them and the "positive electrode (200) not including a current collector" are in contact with each other facing each other.

[0030] When stacking the bicells (2000) as unit cells, as shown in FIG. 3, a positive electrode current collector (220) is stacked on one bicell (2000), and then the remaining bicell (2000) is stacked on the other bicell. This process is repeated at least once to complete the manufacture of an all-solid-state battery (the process of storing the battery inside a storage case such as a pouch may be performed separately). There is no particular limit to the number of repetitions, and it may be set in various ways depending on the scale of the intended all-solid-state battery. At this time, the bicells (2000) are stacked with the "positive electrodes (200) not including a current collector" contained in each of them facing each other, and both sides of the positive electrode current collector (220) interposed between them and the "positive electrodes (200) not including a current collector" are in contact with each other in a facing state.

[0031] In addition, when stacking the bicells (2000) as unit cells, as shown in FIG. 3, a positive electrode current collector (220) may be provided not only between one cell and another cell but also at the outermost edge in the stacking direction of the battery, and may be in contact with the "positive electrode (200) not including a current collector" in a face-to-face state. In other words, when stacking two or more bicells (2000), a positive electrode current collector (220) may be provided at each of the outermost edges in the stacking direction, and may be in contact with the free-standing positive electrode (200). The positive electrode current collector (220) may be any one commonly used in the industry, for example, aluminum foil (Al foil).

[0032] Isostatic pressing is not required during or after the lamination process (step c) described above. In other words, isostatic pressing is not performed after step b) in which the isostatic pressing is performed. In step b), isostatic pressing is already performed for the interfacial bonding between the electrode and solid electrolyte of the monocell (1000) or bicell (2000), so there is no problem with lithium ion migration. During the lamination process of step c), only the bonding between the "positive electrode (200) not including a current collector" and the positive electrode current collector (220) is performed without interfacial bonding between the electrode and solid electrolyte, but this bonding between the "positive electrode (200) not including a current collector" and the positive electrode current collector (220) is sufficient for electronic conduction even with weak contact.

[0033] Therefore, according to the above-mentioned method for manufacturing an all-solid-state battery according to the present invention, each unit cell including a single layer of anode is isostatically pressed and then stacked, and no isostatic pressing is required when stacking is completed. As a result, a short circuit between the anodes does not occur during operation of the battery. In other words, during the manufacture of the all-solid-state battery, both ends of the anode (100) included in either the monocell (1000) or the bicell (2000) maintain a constant distance from each of both ends of the side surface of the cathode (200) included in the adjacent (opposing) monocell (1000) or bicell (2000), and therefore a short circuit between the cathode and anode does not occur during operation of the battery.

[0034] On the one hand, the all-solid-state battery manufactured by the method for manufacturing an all-solid-state battery according to the present invention may be housed in a storage case such as a pouch. And the all-solid-state battery has no particular limitation on its use. In the all-solid-state battery, the positive electrode may contain a positive electrode active material, a conductive material, and a binder in a granular form. Among these, as the positive electrode active material, any material that can be used as the positive electrode active material of an all-solid-state battery may be used without limitation. The positive electrode active material may be a lithium transition metal oxide containing one or more transition metals. For example, the positive electrode active material is LiCoO 2 , LiNiO 2 , LiMnO 2 , Li 2 MnO 3 , LiMn 2 O 4 , Li(Ni a Co b Mn c )O 2 (0 < a < 1, 0 < b < 1, 0 < c < 1, a + b + c = 1), LiNi 1-y Co y O 2 (0 < y < 1), LiCo 1-y Mn y O 2 (0 < y < 1), LiNi 1-y Mn y O 2 (0 < y < 1), Li(Ni a Co b Mn c )O 4 (0 < a < 2, 0 < b < 2, 0 < c < 2, a + b + c = 2), LiMn 2-z Ni z O 4 (0 < z < 2), LiMn 2-z Co z O 4 (0 < z < 2) and may be selected from the group consisting of combinations thereof.

[0035] Also, the binder is mixed with the positive electrode active material and the conductive material, which are fine particles in a powder state, to bond the respective components and assist the growth of the particles. For example, when a sulfide-based solid electrolyte comes into contact with moisture, H 2Since the binder has a moisture-sensitive property such as generating S gas, it is preferable to remove moisture as much as possible from the time of forming the granules. The binder may be an organic binder, and the organic binder means a binder that dissolves or disperses in an organic solvent, particularly N-methylpyrrolidone (NMP), and is distinguished from an aqueous binder that uses water as a solvent or dispersion medium. For example, the binder may be selected from the group consisting of polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polyimide, polyamideimide, polyethylene, polypropylene, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene-butylene rubber, and fluororubber, but is not limited thereto.

[0036] In the all-solid-state battery, the solid electrolyte may include at least one selected from a sulfide-based solid electrolyte, a polymer-based solid electrolyte, and an oxide-based solid electrolyte, and may preferably include only a sulfide-based solid electrolyte. The sulfide-based solid electrolyte may include a lithium salt, and the lithium salt may include Li as an ionizable lithium salt. + X - The anion of such a lithium salt is not particularly limited, but may be represented by F - , Cl - , Br - , I - , NO 3 - , N(CN) 2 - , B.F. 4 - , ClO 4 - , P.F. 6 - , (CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3) 4 PF 2 - 、(CF 3 ) 5 PF - 、(CF 3 ) 6 P - 、CF 3 SO 3 - 、CF 3 CF 2 SO 3 - 、(CF 3 SO 2 ) 2 N - 、(FSO 2 ) 2 N - 、CF 3 CF 2 (CF 3 ) 2 CO - 、(CF 3 SO 2 ) 2 CH - 、(SF 5 ) 3 C - 、(CF 3 SO 2 ) 3 C - 、CF 3 (CF 2 ) 7 SO 3 - 、CF 3 CO 2 - 、CH 3 CO 2 - 、SCN - 、and (CF 3 CF 2 SO 2 ) 2 N - etc. can be mentioned.

[0037] The sulfide-based solid electrolyte contains sulfur (S) and has ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and may include Li-PS-based glass or Li-PS-based glass ceramic. Non-limiting examples of such sulfide-based solid electrolytes include Li 2 SP 2 S 5 , Li 2 S-LiI-P 2 S 5 , Li 2 S-LiI-Li 2 OP 2 S 5 , Li 2 S-LiBr-P 2 S 5 , Li 2 S-LiCl-P 2 S 5 , Li 2 S-Li 2 OP 2 S 5 , Li 2 S-Li 3 PO 4 -P 2 S 5 , Li 2 SP 2 S 5 -P 2 O 5 , Li 2 SP 2 S 5 -SiS 2 , Li 2 SP 2 S 5 -SnS, Li 2 SP 2 S 5 -Al 2 S 3 , Li 2 S-GeS 2 , and Li 2 S-GeS 2 -ZnS, etc., and the sulfide-based solid electrolyte may contain any one or more of these.

[0038] Such a solid electrolyte may also serve the role of a separator membrane in a general lithium secondary battery (i.e., the role of electrically insulating the negative electrode and the positive electrode while allowing lithium ions to pass through). On the other hand, the all-solid-state battery may be utilized as a semi-solid battery including a liquid electrolyte if necessary. In this case, another polymer separator membrane may be further required.

[0039] In the all-solid-state battery, the negative electrode may include a negative electrode active material that can be used in a normal all-solid-state battery. For example, the negative electrode active material may be carbon such as graphitizable carbon and graphite-based carbon; Li x Fe 2 O 3 (0≦x≦1), Li x WO 2 (0≦x≦1), Sn x Me 1-x Me’ y O z (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, elements of Group 1, Group 2, Group 3 of the periodic table, halogens; 0 < x ≦ 1; 1 ≦ y ≦ 3; 1 ≦ z ≦ 8), etc. metal composite oxides; lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; SnO, SnO 2 、PbO、PbO 2 、Pb 2 O 3 、Pb 3 O 4 、Sb 2 O 3 、Sb 2 O 4 、Sb 2 O 5 、GeO、GeO 2 、Bi 2 O 3 、Bi 2 O 4 and Bi 2 O 5 and metal oxides such as Bi

[0040] The present invention also provides a battery module including the all-solid-state battery as a unit cell, a battery pack including the battery module, and a device including the battery pack as a power source. Specific examples of the device include, but are not limited to, a power tool powered by an electric motor, electric vehicles including electric vehicles (EV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), and the like, electric two-wheeled vehicles including electric bicycles (E-bikes) and electric scooters (E-scooters), electric golf carts, and power storage systems.

[0041] Below, preferred embodiments are shown to aid in understanding the present invention. However, these are merely illustrative of the present invention, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope of the scope and technical spirit of the present invention. Naturally, these changes and modifications also fall within the scope of the appended claims.

[0042] [Example 1] Production of all-solid-state battery A monocell having a structure in which a solid electrolyte and a positive electrode (freestanding positive electrode) not including a current collector are sequentially stacked on one side of a negative electrode was subjected to warm isostatic pressing (WIP), and then a positive electrode current collector was stacked on the other side of the freestanding positive electrode not facing the solid electrolyte, and a monocell identical to the isostatically pressed monocell was further stacked on top of the positive electrode so that the freestanding positive electrode and positive electrode current collector faced each other to manufacture an all-solid-state battery. In this case, the length of the negative electrode included in the upper monocell was configured to be the same as the length of the negative electrode included in the lower monocell, and the length of the freestanding positive electrode included in the upper monocell was configured to be the same as the length of the freestanding positive electrode included in the lower monocell, but shorter than the length of the negative electrode.

[0043] Comparative Example 1: Manufacture of an all-solid-state battery An all-solid-state battery was manufactured in the same manner as in Example 1, except that, instead of performing warm isostatic pressing (WIP) in a mono-cell state, warm isostatic pressing (WIP) was performed after all laminations were completed (i.e., isostatic pressing was not performed before lamination).

[0044] [Experimental Example 1] Evaluation of battery charge / discharge The all-solid-state batteries prepared in Example 1 and Comparative Example 1 were charged and discharged under the following conditions, while observing the state of the batteries, and the life characteristics and capacity retention rate of the batteries were also evaluated. The evaluation temperature was 25°C.

[0045] [Charge / discharge conditions] 0.1C charge / discharge (Voltage range: 4.25V-3V, CV 0.05C)

[0046] As a result of observing the state of the batteries while charging and discharging them as described above, it was confirmed that the battery manufactured in Example 1 operated normally, while the battery manufactured in Comparative Example 1 operated imperfectly due to a short circuit during charging. FIG. 4 is a graph comparing the life characteristics and capacity retention rate of secondary batteries manufactured in an embodiment of the present invention and a comparative example. As shown in FIG. 4, the battery manufactured in Comparative Example 1 was not normally charged and discharged due to a short circuit (i.e., a short circuit occurred at the 10th cycle, and the evaluation was terminated), while the battery manufactured in Example 1 was operated without a short circuit, and was therefore capable of normal charging and discharging. [Explanation of symbols]

[0047] 10,100: Negative electrode (10a,100a: Negative electrode current collector, 100b: Negative electrode active material layer) 20: Positive electrode (20a: positive electrode current collector) 200: Freestanding positive electrode 220: Positive electrode current collector 30,300: Solid electrolyte 1000: Monocell 2000: Buysell

Claims

1. a) forming a mono- or bi-cell by sequentially stacking a solid electrolyte and a positive electrode on one or both sides of a negative electrode; b) isostatically pressing the fabricated mono- or bi-cell; c) stacking two or more of the isostatically pressed monocells or bicells, with a positive electrode current collector interposed between one cell and another cell, and bringing both sides of the interposed positive electrode current collector into contact with the positive electrode, respectively.

2. The method for manufacturing an all-solid-state battery according to claim 1, wherein the positive electrode included in the monocell and the positive electrode included in the bicell are free-standing positive electrodes that do not include a positive electrode current collector.

3. The method for manufacturing an all-solid-state battery according to claim 1 , wherein no isostatic pressing is performed after the step b).

4. The method for producing an all-solid-state battery according to claim 2, wherein during the lamination in the step c), only bonding between the free-standing positive electrode and the positive electrode current collector is performed without interfacial bonding between the electrode and the solid electrolyte.

5. The method for producing an all-solid-state battery according to claim 1 , wherein the monocell and the bicell have a negative electrode longer than a positive electrode.

6. 2. The method for producing an all-solid-state battery according to claim 1, wherein the anode of the monocell includes: an anode active material layer; and an anode current collector attached to one surface of the anode active material layer; and a solid electrolyte and a cathode are sequentially laminated on the other surface of the anode active material layer.

7. 2. The method for producing an all-solid-state battery according to claim 1, wherein the bicell negative electrode includes a negative electrode current collector and negative electrode active material layers attached to both sides of the negative electrode current collector, and a solid electrolyte and a positive electrode are sequentially laminated on each of the negative electrode active material layers.

8. 8. The method for producing an all-solid-state battery according to claim 1, wherein the isostatic pressing is selected from the group consisting of warm isostatic pressing (WIP), hot isostatic pressing (HIP) and cold isostatic pressing (CIP).

9. 3. The method for manufacturing an all-solid-state battery according to claim 2, wherein, when two or more bicells are stacked, a positive electrode current collector is provided on each of the outermost edges in the stacking direction to contact the free-standing positive electrode.

10. 8. The method for producing an all-solid-state battery according to claim 1, wherein both ends of a negative electrode included in any one of the monocells or bicells are not in contact with a positive electrode included in a monocell or bicell adjacent to any one of the monocells or bicells during production of the all-solid-state battery.

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