Isostatic pressurization method and device for all-solid-state battery, and battery cell module comprising isostatic pressurization device

Abstract

An isostatic pressurization method for an all-solid-state battery of the present disclosure comprises the steps of: (a) placing a lower jig having an internal space for accommodating an isostatic pressurization fluid and a pouch cell; (b) providing and fixing a ring-shaped first plate having an opening formed at the center inside the lower jig; (c) accommodating the pouch cell in the opening of the first plate while a cup portion faces upward, downward, or in both directions; (d) stacking a second plate having a shape corresponding to the first plate on the upper surface of the first plate to press and fix a sealing portion located on the outer circumference of the pouch cell with the second plate, while continuously keeping the cup portion of the pouch cell exposed outward; and (e) stacking and fixing a plate-shaped upper jig on the upper portion of the lower jig to seal same, and then injecting fluid in the internal space to perform isostatic pressurization.

Description

Method and device for isotropic pressurization of an all-solid-state battery and battery cell module including the isotropic pressurization device

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0167871, filed November 28, 2023, and Korean Patent Application No. 10-2024-0166024, filed November 20, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a method and device for isostatic pressing of an all-solid-state battery, and a battery cell module including the isostatic pressing device.

[0003] With the explosive growth in technological development and demand for mobile devices and automobiles, more research is being conducted on secondary batteries that feature high energy density, discharge voltage, and excellent output stability. Examples of these secondary batteries include lithium-based secondary batteries, such as lithium-sulfur batteries, lithium-ion batteries, and lithium-ion polymer batteries. These secondary batteries can be categorized into cylindrical, prismatic, and pouch-type batteries based on their shape. Interest in and demand for pouch-type battery cells are steadily increasing. Pouch-type battery cells can be stacked with high density, have high energy density per unit weight, are inexpensive, and are easily modified. Therefore, pouch-type battery cells can be manufactured in shapes and sizes suitable for various mobile devices and automobiles.

[0004] Such pouch-type battery cells generally have a structure in which one or more unit cells including a positive electrode, a negative electrode, and a separator interposed therebetween are stacked (i.e., an electrode assembly or stack cell). After the electrode assembly is accommodated in a battery case, an electrolyte can be injected therein, or in the case of an all-solid-state battery, a solid electrolyte can be provided within the electrode assembly from the beginning to be manufactured.

[0005] In an embodiment of the present invention, a method and device for isostatic pressing of an all-solid-state battery, which enable applying high pressure regardless of the size of the cell and enable increasing driving pressure and improving performance of the battery, and a battery cell module including the isostatic pressing device are provided.

[0006] In an embodiment of the present invention, a method for isostatic pressurization of an all-solid-state battery is provided, including the steps of: (a) arranging a lower jig having an internal space for accommodating a fluid for isostatic pressurization and a pouch cell; (b) arranging and fixing a first plate in the shape of a ring having an opening formed in the center thereof inside the lower jig; (c) accommodating a pouch cell in the opening of the first plate with the cup portion facing upward, downward, or both directions; (d) stacking a second plate having a shape corresponding to the first plate on the upper surface of the first plate, thereby pressing and fixing a sealing portion located on the outer periphery of the pouch cell with the second plate, while the cup portion of the pouch cell continues to be exposed to the outside; and (e) stacking and fixing a plate-shaped upper jig on the upper portion of the lower jig to seal it, and then injecting a fluid therein to isostatically pressurize the upper jig.

[0007] In addition, in an embodiment of the present invention, an isostatic pressurization device for an all-solid-state battery is provided, including: an isostatic pressurization jig including a lower jig having an internal space for accommodating a fluid for isostatic pressurization and a pouch cell, and an upper jig for hermetically sealing the internal space; and first and second ring-shaped plates located inside the isostatic pressurization jig, fixing and pressurizing a sealing portion located at the outermost end of the pouch cell from the bottom and top, and exposing the remaining portion of the pouch cell excluding the sealing portion to the fluid.

[0008] In addition, in an embodiment of the present invention, a battery cell module is provided, including: an isostatic pressurization jig including a lower jig having an internal space for accommodating a fluid for isostatic pressurization and a pouch cell, and an upper jig for hermetically sealing the internal space; first and second plates in a ring shape positioned inside the isostatic pressurization jig, the first and second plates fixing and pressing a sealing portion located at the outermost end of the pouch cell from the bottom and top, and exposing the remaining portion of the pouch cell excluding the sealing portion to the fluid; and a pouch cell having a sealing portion positioned between the first and second plates and fixed and pressed through the first and second plates.

[0009] According to the isostatic pressurization method and device for an all-solid-state battery according to an embodiment of the present invention and the battery cell module including the isostatic pressurization device, it is possible to apply a relatively high pressure regardless of the size of the cell, and has the advantage of enabling an increase in driving pressure and an improvement in the performance of the battery.

[0010] The following drawings attached to this specification illustrate embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0011] Figure 1 is an image showing a pouch cell being pressed using a one-axis pressing method.

[0012] FIG. 2 is a schematic diagram showing a pouch cell installed in an isostatic pressing device to isostatically pressurize the pouch cell according to one embodiment of the present invention.

[0013] FIG. 3 is a flowchart illustrating a method of installing a pouch cell in an isostatic pressing device to isostatically pressurize the pouch cell according to one embodiment of the present invention.

[0014] FIG. 4 is a schematic diagram illustrating a laminated structure of an electrode assembly positioned inside an isotropically pressurized pouch cell according to one embodiment of the present invention.

[0015] FIG. 5 is a schematic diagram illustrating an isotropically pressurized pouch cell according to one embodiment of the present invention.

[0016] FIG. 6 is a perspective view illustrating an automobile including a battery pack according to one embodiment of the present invention.

[0017] In some of the accompanying drawings, corresponding components are designated by the same reference numerals. Those skilled in the art will appreciate that the drawings illustrate elements simply and clearly and are not necessarily drawn to scale. For example, to facilitate understanding of various embodiments, the dimensions of some elements depicted in the drawings may be exaggerated relative to other elements. Furthermore, elements of known technology that are useful or essential in commercially feasible embodiments may often not be depicted so as not to obscure the spirit of various embodiments of the present invention.

[0018] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0019] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there are various equivalents and modified examples that can replace them at the time of filing this application.

[0020] In addition, when describing the present invention, if it is determined that the description of a related known structure or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

[0021] As used herein, the terms "about," "approximately," and "substantially" are used to mean a range of or near a numerical value or degree, taking into account inherent manufacturing and material tolerances.

[0022] Since the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, the shapes and sizes of components in the drawings may be exaggerated, omitted, or schematically illustrated for clearer explanation. Accordingly, the sizes and proportions of each component do not fully reflect the actual sizes or proportions.

[0023] All-solid-state batteries replace the liquid electrolyte used in conventional lithium secondary batteries with a solid one. They boast superior safety compared to other types of secondary batteries, and are attracting attention in areas such as electric vehicles and mobile devices. For example, all-solid-state batteries do not use flammable solvents, eliminating the risk of ignition or explosion due to electrolyte decomposition reactions, significantly improving safety. Furthermore, all-solid-state batteries can use lithium metal or lithium alloys instead of graphite as anode materials, offering the advantage of improved energy density relative to the mass and volume of the battery compared to those using liquid electrolytes.

[0024] The solid electrolytes of all-solid-state batteries can be broadly classified into organic (high molecular) solid electrolytes such as polymers and inorganic solid electrolytes, and among these, inorganic solid electrolytes can be divided into sulfide and oxide solid electrolytes. And as of now, the solid electrolyte that has undergone a lot of technological development is the sulfide solid electrolyte, which is an inorganic solid electrolyte, and has an ionic conductivity of 10 -3 S / cm to 10 -2Development has progressed to a level approaching that of organic electrolytes, with a conductivity of S / cm. Thus, sulfide-based solid electrolytes not only possess relatively high ionic conductivity among solid electrolytes, but also exhibit excellent thermal stability and interfacial compatibility due to their ductility, which facilitates good contact with interfaces and improves resistance.

[0025] To manufacture all-solid-state batteries, a pressurization process is applied to improve contact between the all-solid-state electrolyte and the electrodes. However, during the pressurization process, mainly under high-pressure conditions, the edges of the electrodes may detach, which may cause a short circuit in the battery, which may lead to battery ignition or thermal runaway. Therefore, it is necessary to manufacture all-solid-state batteries by ensuring the insulation performance of the edges of the all-solid-state batteries.

[0026] Fig. 1 is a drawing showing a process of pressurizing a pouch-type all-solid-state battery using a uniaxial pressurization method. For example, an all-solid-state battery that uses a sulfide-based solid electrolyte, which is an inorganic solid electrolyte, generally performs a pressurization process of applying high uniaxial pressure using a torque wrench, as illustrated in Fig. 1, for the purpose of minimizing the contact resistance between each layer of the cell and the empty space at the layer boundary during the process of activating or operating the cell. This is because if the interface between the electrode and the solid electrolyte is not completely in contact and the interface between the electrode and the solid electrolyte is not well formed, the movement of lithium (Li) ions is difficult, making battery operation impossible or performance deteriorating. A typical uniaxial pressurization method using a torque wrench is a method of positioning a cell (6) between an upper plate (2) and a lower plate (4), and then pressurizing the cell (6) by moving the upper plate (2) up and down using an elastic member (8) such as a spring. However, in this case, a problem arises where it is not easy or impossible to apply high pressure to the cell as the cell size increases.

[0027] The present invention provides a novel isostatic pressing method and an isostatic pressing device therefor, which do not cause the above problems even when high pressure is applied to a relatively large cell.

[0028] FIG. 2 is a schematic diagram showing a pouch cell installed in an isostatic pressing device to isostatically pressurize the pouch cell according to one embodiment of the present invention. Referring to FIG. 2, the isostatic pressurization device (10) of the all-solid-state battery according to the present invention will be described. The isostatic pressurization device (10) of the all-solid-state battery includes an isostatic pressurization jig (100, 500) including a lower jig (100) having an internal space (S) for accommodating a fluid for isostatic pressurization and a pouch cell (200) and an upper jig (500) for hermetically sealing the internal space (S), and first and second plates (300, 400) in the shape of rings, which are positioned inside the isostatic pressurization jig (100, 500) and fix and pressurize a sealing portion (250) located at the outermost part of the pouch cell (200) from the bottom and top, and expose the remaining portion of the pouch cell excluding the sealing portion (250) to the fluid.

[0029] The first plate (300) and the second plate (400) having the above-described ring shape may have a shape in which one side is opened by forming a first opening (302) and a second opening (402), as illustrated in FIG. 2. Accordingly, in this case, the first and second plates (300, 400) having an open side fix and pressurize the sealing portions (250) on three sides, excluding the sealing portion on the side where the electrode terminal is located, among the four sealing portions (250) located at the outermost part of the pouch cell (200), from the bottom and top.

[0030] As illustrated in FIG. 2, a groove (120) may be further formed along the periphery of the internal space (S) of the lower jig (100) on the upper surface (102) of the lower jig (100). This serves as a means for improving watertightness and airtightness when the upper jig (500) is laminated on top of the lower jig (100) for sealing. By inserting an elastic ring such as an O-ring along the groove (120) and then covering the upper jig (500), the sealing effect can be improved. In addition, an additional description of the configuration of the isostatic pressurization device (10) will be supplemented with a description of the isostatic pressurization method of the all-solid-state battery below.

[0031] FIG. 3 is a flowchart showing a method of installing a pouch cell in an isostatic pressing device to isostatically pressurize the pouch cell, according to one embodiment of the present invention. Referring to FIGS. 2 and 3, the method for isostatic pressurization of an all-solid-state battery according to the present invention comprises the steps of (S100) arranging a lower jig (100) having an internal space for accommodating a fluid for isostatic pressurization and a pouch cell, (S110) arranging and fixing a first plate (300) in the shape of a ring having an opening formed in the center thereof inside the lower jig (100), (S120) accommodating a pouch cell (200) in the opening of the first plate (300) in a state where a cup part (240) of the pouch cell (200) faces upward, downward, or both directions, (S130) laminating a second plate (400) having a shape corresponding to the first plate (300) on the upper surface of the first plate (300) so as to form a sealing part (sealing part, located at the outermost part of the pouch cell (200) (or located at the outermost part of the pouch cell in the horizontal direction) (250) a step of pressing and fixing the second plate (400) while continuously exposing the cup portion (240) of the pouch cell (200) to the outside, and (S140) a step of sealing by stacking and fixing the upper jig (500) in the form of a plate on the upper portion of the lower jig (100), and then injecting a fluid inside to isostatically pressurize the upper portion.

[0032] Hereinafter, each step of the isotropic pressurization method of an all-solid-state battery according to an embodiment of the present invention will be described in more detail.

[0033] In order to isotropically pressurize an all-solid-state battery according to the present invention, first, a lower jig (100) having an internal space (S) for accommodating a fluid for isotropic pressurization and a pouch cell (200) (or having an outer edge portion positioned with a high step, thereby forming an internal space (S) and having an open upper portion) must be placed (S100). The internal space (S) of the lower jig (100) is provided with members for stably settling and fixing the pouch cell (200), such as the pouch cell (200), the first plate (300), and the second plate (400), within the lower jig (100).

[0034] In FIG. 2, it is illustrated that one each of a pouch cell (200), a first plate (300), and a second plate (400) are provided, but this is only for convenience of explanation, and there is no particular limitation on the number of pouch cells and plates provided inside the lower jig (100). For example, in another embodiment of the present invention, two or more pouch cells (200) may be provided in the internal space (S) of the lower jig (100) to perform isostatic pressing simultaneously. For example, a second pouch cell and a third plate (corresponding to the first plate) and a fourth plate (corresponding to the second plate) for fixing the second pouch cell may be additionally provided on the upper portion of the second plate (400) (the stacking order is the same as in FIGS. 2 and 3). That is, when two or more pouch cells are provided in the internal space (S) of the lower jig (100), plates corresponding to the first plate (300) and the second plate (400) may be paired and further provided on the upper portion of the second plate (400). In addition, the number of these may vary depending on the size of the internal space (S) of the lower jig (100).

[0035] Meanwhile, the outer edge portion of the lower jig (100) may be formed as a surface having a predetermined width at the upper portion, as illustrated in FIG. 2, so that the upper jig (500) can be stably stacked and fixed. A screw groove (110) may be formed on the upper surface (102) of the lower jig (100), as illustrated in FIG. 2, so that the upper jig (500) can be fixed with screws. However, this is merely an example, and there is no particular limitation on the method as long as the lower jig (100) and the upper jig (500) can be stably fixed. In addition, as illustrated in FIG. 2, two or more, for example, four or more, support members (104) for position adjustment and shock absorption may be provided on the lower surface of the lower jig (100).

[0036] In the embodiment of FIG. 2, the lower jig (100) is illustrated as having a hexahedral shape. However, this is merely for convenience of explanation, and as long as the pouch cell (200) and plates (300, 400) are provided on the lower jig (100) so that the pouch cell (200) can be stably and isotropically pressurized, there is no particular limitation on the shape of the lower jig (100). In addition, there is no particular limitation on the width or height of the lower jig (100) or the internal space (S) formed in the lower jig (100), and it may be variable depending on the specifications or number of pouch cells.

[0037] After the lower jig (100) is placed as described above, a step (S110) of providing and fixing a ring-shaped first plate (300) having an opening formed in the center thereof to the inside of the lower jig (100) and a step (S120) of accommodating a pouch cell in the opening of the first plate with the cup portion facing upward, downward, or both directions are sequentially performed.

[0038] The first plate (300) has a ring shape including a first opening (302), and the cup portion (240) of the pouch cell (200) can be accommodated in the first opening (302), and a sealing portion (250) located at the outermost horizontal side of the pouch cell (200) can be located on the upper surface of the first plate (300). Accordingly, in this case, the first plate (300) and the second plate (400) fix and press the sealing portion (250) of the pouch cell (200) from the lower and upper sides, and the remaining portion of the pouch cell (200) excluding the sealing portion (250) (e.g., the cup portion and the portion located on the opposite side thereof, etc.) is exposed to the fluid and isotropically pressurized.

[0039] As described above, the first plate (300) and the second plate (400) having a ring shape may have a form in which one side is opened by the first opening (302) and the second opening (402), respectively. Accordingly, in this case, the first and second plates (300, 400) having a form in which one side is opened fix and pressurize the sealing parts (250) on three sides, excluding the sealing parts on the side where the electrode terminals are located, among the four sealing parts (250) located at the outermost part of the pouch cell (200), from the bottom and top.

[0040] In addition, the first plate (300) needs to be fixed to the bottom surface of the internal space (S) of the lower jig (100) by, for example, screwing, etc., so as to support the pouch cell (200) so that it does not come off. In addition, as illustrated in FIG. 2, if the outer circumferential surface of the first plate (300) except for the first opening (302) side is provided in close contact with one end of the internal space (S) of the lower jig (100), the pouch cell (200) can be supported and fixed more stably.

[0041] FIG. 4 is a schematic diagram illustrating a stacked structure of an electrode assembly positioned inside an isotropically pressurized pouch cell (200) according to one embodiment of the present invention. The pouch cell (200) may be a mono-cell in which a solid electrolyte (230) and a positive electrode (or a positive electrode not including a current collector (222) or a free-standing positive electrode, 220) are sequentially stacked on one surface of a negative electrode (210) and a conventional pouch is covered thereon. In addition, the pouch cell (200) may be a bi-cell in which a solid electrolyte (230) and a positive electrode (or a positive electrode not including a current collector (222) or a free-standing positive electrode, 220) are sequentially stacked on each of both surfaces of a negative electrode (210), as illustrated in FIG. 4, and a conventional pouch is covered thereon. In addition, the pouch cell (200) may include a structure greater than a bi-cell, and may include cells with different laminated structures of electrodes and electrolytes.

[0042] As described above, the pouch cell (200) accommodates an electrode assembly such as a monocell or a bicell, and at this time, the edge formed by sealing the pouch covered with the electrode assembly is called a sealing part. In addition, the remaining part excluding the sealing part, that is, the part protruding compared to the sealing part, is called a cup part. Fig. 5 is a schematic diagram illustrating a pouch cell that is isotropically pressed according to an embodiment of the present invention. In the pouch cell (200) of the present invention, the sealing part (250) of the pouch (260) may be located at the outermost side based on the stacking direction of the cells (a of Fig. 5), may be located at the center (b of Fig. 5), or may be located between them, and there are no special limitations.

[0043] Referring to the above, the S120 step will be described in more detail. In terms of considering uniform pressurization, the pouch cell (200) should be accommodated in the opening of the first plate (300) with the cup portion (240) facing upward, downward, or both directions, as illustrated in FIG. 2. Here, when the cup portion (240) faces upward or downward, it corresponds to a pouch cell in which the sealing portion (250) is located at the outermost side based on the stacking direction of the cells, as illustrated in FIG. 5 a. In addition, when the cup portion (240) faces in both directions (upward and downward), it corresponds to a pouch cell in which the sealing portion (250) is located at the center or between the center and the outermost side based on the stacking direction of the cells, as illustrated in FIG. 5 b.

[0044] In addition, the appearance after the pouch cell (200) is accommodated in the first opening (302) of the first plate (300) may be such that both the cup portion (240) and the sealing portion (250) of the pouch cell (200) are exposed to the outside, as illustrated in FIG. 2. At this time, the sealing portion (250) of the pouch cell (200) may be positioned in a state of being seated on the upper surface of the first plate (300) so as to be supported by the upper surface of the first plate (300). Accordingly, the height of the upper surface of the sealing portion (250) located on the outer periphery of the cup portion (240) of the pouch cell (200) may be higher than the height of the upper surface of the first plate (300). However, if the sealing portion (250) is supported by the first plate (300), the height of the upper surface of the sealing portion (250) of the pouch cell (200) may be the same as the height of the upper surface of the first plate (300). On the other hand, if the height of the upper surface of the sealing portion (250) of the pouch cell (200) is lower than the height of the upper surface of the first plate (300), it is difficult to pressurize through the second plate (400), and therefore, the height of the upper surface of the sealing portion (250) of the pouch cell (200) may be the same as or higher than the height of the upper surface of the first plate (300).

[0045] Continuing, as described above, after the first plate (300) is provided and fixed inside the lower jig (100) and the pouch cell (200) is received in the opening of the first plate (300), a step of laminating a second plate (400) having a shape corresponding to the first plate (300) on the upper surface of the first plate (300) is performed (S130).

[0046] The above second plate (400) is a member for pressing and fixing the sealing portion (250) located on the outer periphery of the pouch cell (200) (or located at the outermost horizontal side of the pouch cell).

[0047] According to one embodiment, the second plate (400) may overlap the opening of the first plate (300). As a result, the sealing portion (250) can be fixed and pressed with a uniform pressure from the top and bottom. Accordingly, the lower surface of the second plate (400) naturally comes into contact with the sealing portion (250) of the pouch cell (200), and in this state, is fastened to the first plate (300) to press the sealing portion (250). That is, the sealing portion (250) of the pouch cell (200) interposed between the upper surface of the first plate (300) and the lower surface of the second plate (400) can be pressed. The cup portion (240) of the pouch cell (200) must remain continuously exposed to the outside (for isotropic pressing in the final stage).

[0048] The second plate (400) may be attached to the upper portion of the first plate (300) by a fastening means such as a screw connection, or may be attached to the upper portion of the first plate (300) by using an adhesive that is easy to remove. However, considering the convenience of repeated work, the first plate (300) and the second plate (400) may each be formed with a screw groove (310, the screw groove formed in the second plate is not shown) and fixed by fastening using a screw and a bolt.

[0049] Meanwhile, the upper surface of the second plate (400) may be positioned on the same line as the upper surface (102) of the lower jig (100) in the vertical direction, as illustrated in FIG. 2, or may be positioned higher than the upper surface (102) of the lower jig (100). In this case, since the lower surface of the upper jig (500) and the upper surface of the second plate (400) come into contact, when the upper jig (500) is fixed to the upper surface of the lower jig (100), additional pressurization of the sealing portion (250) of the pouch cell (200) may be performed. Therefore, including this configuration, the pouch cell can be fixed more thoroughly during isostatic pressing.

[0050] As described above, after the second plate (400) is laminated on the upper surface of the first plate (300) with the sealing portion (250) interposed therebetween, the upper jig (500) in the form of a plate is finally laminated and fixed on the upper side of the lower jig (100) to seal it, and then a step of isotropically pressurizing by injecting a fluid (for isotropic pressurization) into the interior is performed (S140). Here, there is no particular limitation on the type of the fluid for isotropic pressurization.

[0051] According to one embodiment, the upper jig (500) may be coupled to the upper portion of the lower jig (100) by a fastening means such as a screw connection, or may be attached to the upper portion of the lower jig (100) by using an adhesive that is watertight and airtight while also being easy to remove. In addition, a method of tying the lower jig (100) and the upper jig (500) with a string or an elastic band is also possible, and as long as the upper jig (500) is not separated from the lower jig (100), it may be applied without any particular limitation. However, in consideration of convenience for repetitive work, a screw groove (110) may be formed in each of the lower jig (100) and the upper jig (500) so that they may be fastened by a screw / bolt. In addition, by inserting the elastic ring described above into the groove (120) that may be formed on the upper surface (102) of the lower jig (100), the watertightness and airtightness can be further improved. Meanwhile, there is no special limitation on the specifications of the upper jig (500) as long as the fluid for isostatic pressurization injected into the internal space (S) does not leak out to the outside and does not adversely affect isostatic pressurization.

[0052] The above isostatic pressing may be any one method selected from the group consisting of warm isostatic pressing (WIP), hot isostatic pressing (HIP), and cold isostatic pressing (CIP). In addition, these isostatic pressings may be performed at a temperature within an appropriate range in which the electrode constituent materials are thermally stable while ensuring good interfacial contact between electrodes through the molding of the solid electrolyte. For example, the warm isostatic pressing (WIP) may be performed at about 45°C to 100°C.

[0053] Meanwhile, it is preferable that the lower jig (100) and the upper jig (500) are made of materials having no or very small pores. In particular, this is because cracks may occur if there are pores in the jigs (100, 500) during the isostatic pressing process. Therefore, the lower jig (100) and the upper jig (500) may have a porosity of less than about 1%, for example, less than about 0.5%, or less than about 0.1%. In addition, for example, the lower jig (100) and the upper jig (500) may each be made of any one of steel and ceramic, but the present invention is not limited thereto. In addition, the lower jig (100) and the upper jig (500) may be made of the same material or may be made of different materials, and there is no particular limitation thereon. In addition, plate members such as the first plate (300) and the second plate (400) provided in the internal space (S) of the lower jig (100) may also be made of a material having the same porosity as above, but are not limited thereto.

[0054] Meanwhile, in the all-solid-state battery used in the present invention, the positive electrode may include a positive electrode active material, a conductive material, and a binder in the form of granules. Among these, the positive electrode active material may be used without limitation as long as it can be used as a positive electrode active material of an all-solid-state battery. 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 may be LiCoO2, LiNiO2, LiMnO2, Li2MnO3, LiMn2O4, Li(Ni a Co b Mn c )O2(0 <a<1, 0<b<1, 0<c<1, a+b+c=1), LiNi 1-y Co y O2(O <y<1), LiCo 1-y Mn y O2, LiNi 1-y Mn y O2(O <y<1), Li(Ni a Co b Mn c )O4(0 <a<2, 0<b<2, 0<c<2, a+b+c=2), LiMn 2-z Ni z O4(0 <z<2), LiMn 2-z Co z O4(0 <z<2) 및 이의 조합으로 이루어진 군으로부터 선택되는 것일 수 있다.

[0055] In addition, the binder is mixed with the positive electrode active material and conductive material, which are fine particles in a powder state, to bind each component and help the growth of the particles. For example, since a sulfide-based solid electrolyte has a moisture-sensitive characteristic such as generating H2S gas when in contact with moisture, it is desirable to exclude 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 is dissolved or dispersed 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, but is not limited to, 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 fluoroelastomer.

[0056] In the above 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 according to one embodiment, may include only a sulfide-based solid electrolyte. The sulfide-based solid electrolyte may include a lithium salt, and the lithium salt is an ionizable lithium salt such as Li + X - It can be expressed as . The anion of this lithium salt is not particularly limited, but F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 -, (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - Examples include:

[0057] In addition, the sulfide-based solid electrolyte contains sulfur (S) and has the 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 Li2S-P2S5, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-LiCl-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2O5, Li2S-P2S5-SiS2, Li2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-GeS2, and Li2S-GeS2-ZnS, and the sulfide-based solid electrolyte may include any one or more thereof.

[0058] These solid electrolytes can perform the same role as separators in conventional lithium secondary batteries (i.e., electrically insulating the anode and cathode while simultaneously allowing lithium ions to pass through). Meanwhile, the all-solid-state battery can be utilized as a semi-solid battery by including a liquid electrolyte, if necessary. In this case, a separate polymer separator may be required.

[0059] In the above all-solid-state battery, the negative electrode may include a negative electrode active material usable in a typical all-solid-state battery. For example, the negative electrode active material may include carbon such as non-graphitizable carbon, graphite carbon, etc.; Li x Fe2O3(0≤x≤1), Li x WO2(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, 2, and 3 of the periodic table, halogens; 0 <x≤1; 1≤y≤3; 1≤z≤8) 등의 금속 복합 산화물; 리튬 금속; 리튬 합금; 규소계 합금; 주석계 합금; SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4및 Bi2O5등의 금속 산화물; 폴리아세틸렌 등의 도전성 고분자; Li-Co-Ni계 재료; 티타늄 산화물; 리튬 티타늄 산화물; 등에서 선택된 어느 하나 이상을 포함한 것일 수 있다.

[0060] FIG. 6 is a schematic perspective view of a vehicle (30) including a battery pack (20) according to one embodiment of the present invention.

[0061] Referring to FIG. 6, the present invention provides a battery module including the all-solid-state battery as a unit battery, a battery pack (20) including the battery module, and a device including the battery pack as a power source.

[0062] Examples of the above devices include, but are not limited to, power tools that are powered by an electric motor; electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs); electric two-wheeled vehicles including electric bicycles (E-bikes) and electric scooters (E-scooters); electric golf carts; and power storage systems. For example, the automobile (30) may be operated by receiving power from a battery pack (20) according to an embodiment of the present invention.

[0063] In addition, the present invention also provides a battery cell module that includes an isotropic pressurizing device for an all-solid-state battery described above and a battery cell mounted thereon as an integral unit.

[0064] That is, the battery cell module includes an isostatic pressurization jig (100, 500) including a lower jig (100) having an internal space (S) for accommodating a fluid for isostatic pressurization and a pouch cell (200) and an upper jig (500) for hermetically sealing the internal space (S), a first and second plates (300, 400) in a ring shape located inside the isostatic pressurization jig (100, 500) and fixing and pressurizing a sealing portion (250) located at the outermost part of the pouch cell (200) from the bottom and top, and exposing the remaining portion of the pouch cell excluding the sealing portion (250) to the fluid, and a pouch cell (200) with the sealing portion (250) located between the first and second plates (300, 400) and being fixed and pressurized through the first and second plates (300, 400).

[0065] The isostatic pressurization device (10) of the all-solid-state battery described above can be used not only in the process of activating the battery cell in a form in which the battery cell is excluded, but also in the cell manufacturing stage prior to activation.

[0066] Meanwhile, when the pouch cell (200) is integrated into the isostatic pressurization device (10) of the all-solid-state battery described above and used in the form of a battery cell module, it can be applied not only to the process of activating the battery cell, but can also be installed in the product itself, such as an automobile, so that the battery cell can be isostatically pressed relatively easily even during the process of operating the battery. Even if isostatic pressurization is performed during the process of manufacturing or activating the battery cell, as time passes or charging and discharging are repeated, the contact resistance between each layer of the cell increases, and empty space is bound to be formed again at the layer boundary. However, when it is installed in the product in the form of a module as described above, isostatic pressurization is performed even during the charging and discharging of the battery, so that the above problems can be eliminated or minimized. In addition, since the pressure is not applied only along one axis, it has the advantage of not deteriorating the performance of the battery even if the operating pressure of the battery increases. Referring to FIG. 6, in accordance with one embodiment of the present invention, a vehicle (30) may be equipped with the battery cell module described above instead of the battery pack (20). In this case, the vehicle (30) may operate by receiving power from the battery cell module instead of the battery pack (20).

[0067] Moreover, the present invention can perform isostatic pressing simultaneously by providing two or more pouch cells (200) in the internal space (S) of the lower jig (100). At this time, for example, a second pouch cell and a third plate (corresponding to the first plate) and a fourth plate (corresponding to the second plate) for fixing the second pouch cell may be additionally provided on the upper side of the second plate (400) (the stacking order is the same as in FIGS. 2 and 3). That is, when two or more pouch cells are provided in the internal space (S) of the lower jig (100), plates corresponding to the first plate (300) and the second plate (400) may be paired and further provided on the upper side of the second plate (400). In addition, the number of these may vary depending on the size of the internal space (S) of the lower jig (100). Therefore, if a battery cell module including a plurality of cells as an integral unit together with an isostatic pressurization device is provided in a product, it also has the advantage of being able to implement a large capacity battery.

[0068] Hereinafter, examples are presented to help understand the present invention, but these are only illustrative of the present invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and technical idea of ​​the present invention, and it is also natural that such changes and modifications fall within the scope of the appended patent claims.

[0069] [Example 1] Isotropic pressurization of an all-solid-state battery

[0070] First, a lower jig having an open upper portion with a high step at the outer edge and an internal space formed thereby was placed, and then a first plate having one side opened in the shape of a pouch cell was placed and fixed inside the lower jig. Next, a pouch cell was accommodated in the opening of the first plate, and a second plate having a shape corresponding to the first plate was laminated on the upper surface of the first plate, such that the sealing portion located at the outer periphery of the pouch cell was pressed and fixed by the second plate, while the cup portion of the pouch cell was continuously exposed to the outside. Finally, a plate-shaped upper jig was laminated and fixed on the upper portion of the lower jig to seal it, and then a fluid was injected inside to perform warm isostatic pressing (WIP) while the battery was being operated (or during charge and discharge). Meanwhile, the lower jig, the first plate, the second plate, and the upper jig were all made of steel having a porosity of less than 1%.

[0071] [Example 2] Isotropic pressurization of an all-solid-state battery

[0072] The same procedure as Example 1 was followed, except that a groove was further formed on the upper surface of the lower jig, an elastic ring was inserted into it, and the upper jig was laminated.

[0073] [Comparative Example 1] Uniaxial pressurization of an all-solid-state battery

[0074] The cell was pressurized during battery operation (or during charging and discharging) using a conventional process of applying high uniaxial pressure using a torque wrench, as illustrated in Fig. 1.

[0075] [Experimental Example 1] Performance Evaluation of a Pressurized Cell

[0076] In the above Examples 1 and 2 and Comparative Example 1, the performance of the pressurized cell during battery operation (or, during charge and discharge) was evaluated. As a result, in the case of Examples 1 and 2 in which the pouch cell was isostatically pressed using the jig and plate of the present invention, there was no problem in operating the battery and the performance of the battery was not deteriorated even when high pressure was applied during battery operation or charge and discharge. On the other hand, in the case of Comparative Example 1 in which a torque wrench was used to apply high uniaxial pressure to the cell, cell rupture or cracking occurred due to the increase in pressure during battery operation or charge and discharge, making it impossible to operate the battery itself.

[0077] [Explanation of symbols]

[0078] 100: Lower jig (S: inner space, 102: upper surface, 104: support member, 110: screw groove, 120: groove)

[0079] 200: Pouch cell (210: cathode, 220: anode, 230: electrolyte, 240: cup part, 250: sealing part, 260: pouch)

[0080] 300: first plate (302: first opening, 310: screw groove)

[0081] 400: Second plate (402: Second opening)

[0082] 500: Upper jig

Claims

1. (a) A step of arranging a lower jig having an internal space for accommodating a fluid for isostatic pressurization and a pouch cell; (b) a step of providing and fixing a first plate in the shape of a ring with an opening formed in the center inside the lower jig; (c) accommodating the pouch cell in the opening of the first plate with the cup portion facing upward, downward or both; (d) a step of laminating a second plate having a shape corresponding to the first plate on the upper surface of the first plate, thereby pressing and fixing the sealing portion located on the outer periphery of the pouch cell with the second plate, while continuously exposing the cup portion of the pouch cell to the outside; and (e) A method for isostatic pressurization of an all-solid-state battery, comprising the steps of: (a) sealing by stacking and fixing a plate-shaped upper jig on the upper part of the lower jig, and then injecting a fluid inside to isostatically pressurize.

2. A method for isostatic pressing of an all-solid-state battery, wherein the sealing portion of the pouch cell according to claim 1 is mounted on the upper surface of the first plate and supported by the upper surface of the first plate.

3. In claim 2, a method for isostatic pressing of an all-solid-state battery, wherein the lower surface of the second plate is in contact with the sealing portion of the pouch cell, and in this state, the sealing portion of the pouch cell is pressed between the upper surface of the first plate and the lower surface of the second plate by being fastened with the first plate.

4. A method for isostatic pressing of an all-solid-state battery, wherein the sealing portion of the pouch cell accommodated in the opening of the first plate according to claim 1 has an upper surface height that is the same as or higher than the upper surface height of the first plate.

5. A method for isotropically pressing an all-solid-state battery according to claim 1, wherein the upper surface of the second plate is positioned on the same line as the upper surface of the lower jig in the vertical direction, or is positioned higher than the upper surface of the lower jig.

6. A method for isostatic pressing of an all-solid-state battery according to claim 5, wherein the lower surface of the upper jig and the upper surface of the second plate are in contact, and when the upper jig is fixed to the upper surface of the lower jig, additional pressurization of the sealing portion of the pouch cell is performed.

7. A method for isostatic pressing of an all-solid-state battery according to claim 1, wherein one side of the first and second plates having the ring shape is opened, and three sealing portions, excluding the sealing portion on the surface where the electrode terminal is located among the four sealing portions located at the outermost horizontal direction of the pouch cell, are fixed and pressed from below and above.

8. A method for isostatic pressurization of an all-solid-state battery according to claim 1, wherein two or more pouch cells are provided in the internal space of the lower jig.

9. A method for isostatic pressing of an all-solid-state battery according to claim 8, wherein a plate corresponding to the first plate and the second plate is provided as a pair and is further provided on the upper side of the second plate.

10. A method for isostatic pressing of an all-solid-state battery according to claim 1, wherein the lower jig, the first plate, the second plate, and the lower jig are each made of one of steel and ceramic having a porosity of less than about 1%.

11. A method for isostatic pressurization of an all-solid-state battery according to claim 1, wherein the pouch cell includes a structure of more than a monocell or a bicell.

12. A method for isostatic pressurization of an all-solid-state battery according to claim 1, wherein the all-solid-state battery is a sulfide-based all-solid-state battery.

13. An isostatic pressurizing jig including a lower jig having an internal space for accommodating an isostatic pressurizing fluid and a pouch cell, and an upper jig for hermetically sealing the space; and An isostatic pressurizing device for an all-solid-state battery, comprising first and second plates in the shape of rings, which are positioned inside the isostatic pressurizing jig, fix and pressurize a sealing portion located at the outermost part of a pouch cell from the bottom and top, and expose the remaining part of the pouch cell excluding the sealing portion to a fluid.

14. An isostatic pressurizing device for an all-solid-state battery according to claim 13, wherein one side of the first and second plates having the ring shape is opened, and three sealing portions, excluding the sealing portion on the surface where the electrode terminal is located among the four sealing portions located at the outermost part of the pouch cell, are fixed and pressed from below and above.

15. An isostatic pressurizing jig including a lower jig having a space for accommodating a fluid for isostatic pressurization and a pouch cell, and an upper jig for hermetically sealing the internal space; First and second plates in the form of rings, positioned inside the above isostatic pressurizing jig, fixing and pressurizing the sealing portion located at the outermost part of the pouch cell from the bottom and top, and exposing the remaining part of the pouch cell excluding the sealing portion to the fluid; and A battery cell module comprising a pouch cell, wherein a sealing portion is positioned between the first and second plates and the pouch cell is fixed and pressurized through the first and second plates.

16. A battery cell module according to claim 15, wherein two or more pouch cells are provided in the internal space of the lower jig, and plates corresponding to the first plate and the second plate are paired and further provided on the upper portion of the second plate.

17. A battery cell module according to claim 15, characterized in that the battery cell module is applied to a process of activating a battery cell or is provided in a product, and when the battery cell module is provided in a product, isostatic pressurization is performed even during charging and discharging of the battery.

18. A vehicle comprising a battery cell module according to claim 15.

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