All-solid-state battery pressing system

Abstract

The present invention relates to an all-solid-state battery pressing system comprising: a jig for vertically pressing an all-solid-state battery; and a hydraulic press for applying uniform pressure to the jig, wherein constant pressure is applied to the jig by means of the pressure applied from the hydraulic press.

Description

All-solid-state battery pressurization system

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0164806, filed November 23, 2023, and Korean Patent Application No. 10-2024-0167560, filed November 21, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an all-solid-state battery pressurization system.

[0003] A secondary battery is a device that converts external electrical energy into chemical energy, stores it, and then generates electricity when needed. They are also called rechargeable batteries, as they can be recharged multiple times. Common secondary batteries include lead-acid batteries, nickel-cadmium (NiCd), nickel-metal hydride (NiMH), and lithium secondary batteries. Compared to disposable primary batteries, secondary batteries offer both economic and environmental benefits.

[0004] Meanwhile, with the gradual advancement of wireless communication technology, demand for lighter, thinner, and smaller portable devices and automotive components is increasing, leading to a growing demand for secondary batteries as the energy source for these devices. In particular, with the commercialization of hybrid and electric vehicles to prevent environmental pollution, research is focusing on using secondary batteries in next-generation automotive batteries to reduce manufacturing costs and weight while extending their lifespan. Among various secondary batteries, lithium secondary batteries have recently been attracting attention due to their lightweight nature, high energy density, high operating potential, and long cycle life.

[0005] In general, lithium secondary batteries are manufactured by mounting an electrode stack composed of a negative electrode, a positive electrode, and a separator inside a cylindrical or square metal can or a pouch-shaped case made of aluminum laminate sheet, and injecting an electrolyte into the electrode stack.

[0006] Conventionally, liquid electrolytes, consisting of lithium salts dissolved in non-aqueous organic solvents, have been primarily used for lithium secondary batteries. However, these liquid electrolytes not only present a high risk of electrode material degradation and organic solvent volatilization, but also pose a risk of combustion or explosion due to increased ambient and battery temperature, as well as the risk of leakage. This complicates the implementation of various safe lithium secondary batteries.

[0007] Meanwhile, all-solid-state batteries using solid electrolytes have the advantage of being able to produce electrode stacks in a safe and simple form because they exclude organic solvents.

[0008] All-solid-state batteries can be categorized into oxide, polymer, and sulfide types, depending on the raw material used for the solid electrolyte. Sulfide-based all-solid-state batteries are attracting attention for their superior lithium-ion conductivity compared to other types of batteries. However, despite these superior characteristics, they have higher ionic conductivity and electrical resistance between the anode and cathode than liquid batteries, resulting in lower lifespan and output compared to batteries utilizing conventional liquid electrolytes.

[0009] Meanwhile, secondary batteries are manufactured through a process of cell assembly and battery activation. During the battery activation stage, the battery cells are mounted on a charging / discharging device, such as a jig, and charged and discharged under the conditions necessary for activation. This process of performing the required charging / discharging using a jig to activate the battery is called the formation process.

[0010] All-solid-state batteries, like secondary batteries, also undergo a charge-discharge process. This requires applying pressure to the cells using jigs or other devices. Currently, pressurizing cells involves tightening the screws on the jigs one by one using a torque wrench. However, this method suffers from the problem of not applying uniform pressure to the cells. Furthermore, as the cell surface area increases, the pressure required increases, and the method of simply tightening the screws without press equipment has limitations.

[0011] Therefore, in order to solve the above problem, research is needed on a pressurization system for an all-solid-state battery that can apply uniform pressure to the entire cell area.

[0012] (Patent Document 1) U.S. Patent Publication No. 2023-0028855

[0013] The purpose of the present invention is to provide a pressurization system for an all-solid-state battery capable of applying uniform pressure to the entire cell area during charging and discharging of the all-solid-state battery.

[0014] To achieve the above purpose,

[0015] The present invention provides an all-solid-state battery pressurization system comprising a jig for vertically pressurizing an all-solid-state battery; and a hydraulic press for applying uniform pressure to the jig; and in which a constant pressure is applied to the jig by the pressure applied by the hydraulic press.

[0016] In one embodiment of the present invention, the solid-state battery pressurization system includes a plurality of jigs, and the plurality of jigs may have different areas in contact with the solid-state battery.

[0017] In one embodiment of the present invention, the plurality of jigs are each pressurized by a plurality of hydraulic presses, and the plurality of hydraulic presses may be connected from one hydraulic cylinder through a plurality of hydraulic connection pipes.

[0018] In one embodiment of the present invention, the plurality of jigs include a first jig and a second jig, and the area of ​​the first jig is 6,000 mm 2 Below, the area of ​​the second jig is 6,000 mm 2 It may be excessive.

[0019] In one embodiment of the present invention, the first jig may control the pressure in units of 0.5 to 3 bar, and the second jig may control the pressure in units of more than 3 to 8 bar.

[0020] In one embodiment of the present invention, when a certain pressure is applied to the jig by the pressure applied from the hydraulic press and the thickness of the solid-state battery is reduced, the screw of the jig may be tightened to maintain the pressure.

[0021] In one embodiment of the present invention, the screw of the jig may be tightened to maintain the pressure applied to the all-solid-state battery, and then the pressure applied from the hydraulic press may be removed.

[0022] In one embodiment of the present invention, the screw of the jig may be tightened to maintain the pressure applied to the all-solid-state battery, and then the pressure applied from the hydraulic press may be removed.

[0023] In one embodiment of the present invention, the all-solid-state battery may be a sulfide-based all-solid-state battery.

[0024] The pressurization system of the all-solid-state battery of the present invention has the effect of increasing the charge / discharge efficiency of the cell, improving the rate performance of the cell, and improving the charge / discharge cycle of the cell, by applying uniform pressure to the cell even when the cell area increases.

[0025] Figure 1 is a photograph showing a pressurization system of an all-solid-state battery according to a conventional invention.

[0026] Figure 2 is a schematic diagram showing a pressurization system of an all-solid-state battery according to one embodiment of the present invention.

[0027] Figure 3 is a schematic diagram showing a pressurization system of an all-solid-state battery according to one embodiment of the present invention.

[0028] Figure 4 is a schematic diagram showing a pouch manufactured to pressurize an all-solid-state battery according to one embodiment of the present invention.

[0029] FIG. 5 is a photograph showing the results of a pressurized all-solid-state battery according to a pressurization system of an all-solid-state battery according to one embodiment of the present invention.

[0030] Hereinafter, the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily practice the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0031] In order to clearly explain the present invention, parts that are not related to the description are omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0032] In addition, 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.

[0033] Hereinafter, embodiments will be described in detail with reference to the attached drawings. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0034]

[0035] Among conventional all-solid-state batteries, all-solid-state batteries that use sulfide-based solid electrolytes go through a charge-discharge process, during which pressure must be applied to the cell using a jig or the like. Conventionally, as illustrated in Fig. 1, a method of tightening the screws of a jig one by one using a torque wrench to pressurize the cell has been used, but this method is not only cumbersome but also has the problem of not applying uniform pressure to the cell. In addition, as the cell area increases, a greater pressure must be applied, but the method of tightening the screws without a press device has limitations.

[0036] Therefore, in order to solve the above problem, research is needed on a pressurization system for an all-solid-state battery that can apply uniform pressure to the entire cell area.

[0037]

[0038] Accordingly, the inventors of the present invention have developed a method to apply uniform pressure to the entire cell area of ​​an all-solid-state battery.

[0039] The present invention has been completed by finding out that the above problem can be solved by means of an all-solid-state battery pressurization system including a jig for vertically pressurizing an all-solid-state battery and a hydraulic press for applying uniform pressure to the jig, and in which a constant pressure is applied to the jig by the pressure applied from the hydraulic press.

[0040]

[0041] The present invention relates to an all-solid-state battery pressurization system,

[0042] Specifically, it includes a jig for pressurizing an all-solid-state battery upward and downward; and a hydraulic press for applying uniform pressure to the jig.

[0043] The all-solid-state battery pressurization system of the present invention can apply a constant pressure to the upper and lower portions of the all-solid-state battery by applying a constant pressure to the jig by the pressure applied from the hydraulic press.

[0044] The all-solid-state battery pressurization system of the present invention includes a plurality of jigs, as illustrated in FIG. 2, and the plurality of jigs may have different areas in contact with the all-solid-state battery. By using a plurality of jigs with different areas, the all-solid-state battery pressurization system of the present invention can apply different pressures to the jigs.

[0045]

[0046] The all-solid-state battery pressurization system of the present invention can maintain the pressure by tightening the screws of the jig when a certain pressure is applied to the jig by the pressure applied by the hydraulic press and the thickness of the all-solid-state battery is reduced. As the hydraulic press applies pressure to the jig, the screws of the jig become loose, and when the screws are tightened by the amount of looseness, the pressure applied by the hydraulic press can be maintained.

[0047] The all-solid-state battery pressurization system of the present invention can maintain the pressure applied to the all-solid-state battery by tightening the screw of the jig, and then remove the pressure applied by the hydraulic press. As described above, when the screw is tightened, the pressure applied by the hydraulic press can be maintained. In this case, even if the pressure applied by the hydraulic press is removed, the pressure applied to the all-solid-state battery by the jig can be maintained.

[0048] In the present invention, the plurality of jigs are each pressurized by a plurality of hydraulic presses, and the plurality of hydraulic presses can be connected from a single hydraulic cylinder (30) through a plurality of hydraulic connection pipes (31, 32), as shown in FIG. 3. One hydraulic press (21, 22) is arranged for each jig (11, 12), and as the hydraulic press (21, 22) applies pressure to one side of the jig (11, 12), pressure is also applied to the all-solid-state battery. A means for applying pressure to the hydraulic presses (21, 22) is a hydraulic cylinder (30). In the present invention, the hydraulic cylinder (30) applies pressure to a plurality of hydraulic presses (21, 22) through a plurality of hydraulic connection pipes (31, 32). Since a plurality of hydraulic connection pipes (31, 32) are connected to one hydraulic press (21, 22), it is connected to a plurality of hydraulic presses (21, 22), and through this, pressure can be applied to a plurality of jigs (11, 12).

[0049] In the present invention, although there is only one hydraulic cylinder (30), the pressure applied thereto can be changed by adjusting the area of ​​the jig (11, 12) connected thereto differently. Each time one hydraulic cylinder (30) pumps, the cylinder moves by a certain distance, which is defined as the movement distance. In this way, each pumping has a certain movement distance, and accordingly, pressure can be additionally applied at a certain value. This movement distance varies depending on the pressure of the cylinder. For example, if the area of ​​the cylinder is 71.15 cm 2 In this case, the cylinder travel distance per pumping is 0.13 mm. In this case, the pressure applied to the jig with an external area of ​​7 cm x 7 cm increases by 1 bar per pumping. Similarly, if the cylinder area is 33.2 cm 2In this case, the cylinder travel distance per pumping is 1.1 mm (if 13 bar or less) or 0.28 mm (if 13 bar or more), and in this case, the pressure applied to the jig with an external area of ​​8 cm * 10 cm increases by 5 bar per pumping.

[0050] By varying the area (outer area) of the jig in this way, the pressure applied to the jig can be varied. Accordingly, in the present invention, when the plurality of jigs include a first jig and a second jig, the area of ​​the first jig is 6,000 mm 2 Below, the area of ​​the second jig is 6,000 mm 2 It can be set to be excessive.

[0051] In this case, the first jig provided in the all-solid-state battery pressurization system of the present invention can control the pressure in units of 0.5 to 3 bar, and the second jig can control the pressure in units of more than 3 to 8 bar.

[0052] The above pressure can be controlled using a gauge (Gauge, 40), a manual valve (50), a manual pump (60), etc., and the gauge, valve, and pump can be those commonly used in the industry.

[0053]

[0054] In the present invention, an all-solid-state battery pressurized by an all-solid-state battery pressurization system may include a positive electrode, a negative electrode, and a solid electrolyte. In addition, the all-solid-state battery may further include a positive electrode lead and a negative electrode lead connected to each of the positive electrode and the negative electrode, respectively.

[0055] The all-solid-state battery may be a pouch-type battery cell in which a positive electrode, a negative electrode, and a solid electrolyte are embedded in a pouch, and portions of the positive electrode lead and the negative electrode lead are exposed to the outside of the pouch. The pouch-type battery cell may be manufactured by placing a solid electrolyte between the positive electrode and the negative electrode, bonding the layers by applying pressure, and then attaching the positive electrode lead and the negative electrode lead to form an electrode assembly, which is then stored in a pouch and sealed.

[0056] However, the structure of the all-solid-state battery pressurized by the all-solid-state battery pressurization system according to one embodiment of the present invention is not limited thereto.

[0057] The configuration of the positive electrode, negative electrode, solid electrolyte layer, positive electrode lead, negative electrode lead and pouch included in the above-mentioned all-solid-state battery may be used without any special restrictions as long as it is used in an all-solid-state battery used in the relevant industry, but it may preferably be a sulfide-based all-solid-state battery.

[0058] In the present invention, the all-solid-state battery may be a sulfide-based all-solid-state battery. Accordingly, the positive electrode, negative electrode, and solid electrolyte layer included in the all-solid-state battery of the present invention may include a sulfide-based solid electrolyte.

[0059] The above 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-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2S5, Li2S-P2S5-SiS2, Li2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-GeS2, Li2S-GeS2-ZnS, etc., and may include one or more of these. However, the present invention is not particularly limited thereto.

[0060] The solid electrolyte layer of the present invention can be manufactured using the sulfide-based solid electrolyte. The method for forming the solid electrolyte layer is not particularly limited as long as it is a method used in the art. For example, the solid electrolyte layer may be manufactured by mixing solid electrolyte powder, binder, and solvent to manufacture a slurry containing a sulfide-based solid electrolyte, then applying the slurry onto a current collector on which an electrode is formed, and drying and rolling the slurry. Any material that does not react with sulfur in the binder and solvent in the solid electrolyte may be used without particular limitation.

[0061] A positive electrode according to one embodiment of the present invention may include a positive electrode current collector, a positive electrode active material, and a solid electrolyte.

[0062] The above positive electrode current collector is intended to support the positive electrode active material, and is not particularly limited as long as it has excellent conductivity and is electrochemically stable in the voltage range of the lithium secondary battery. For example, the positive electrode current collector may be any one metal selected from the group consisting of copper, aluminum, stainless steel, titanium, silver, palladium, nickel, alloys thereof, and combinations thereof. The stainless steel may be surface-treated with carbon, nickel, titanium, or silver. As the alloy, an aluminum-cadmium alloy may be preferably used. In addition, calcined carbon, a non-conductive polymer surface-treated with a conductive material, or a conductive polymer may be used.

[0063] The above positive electrode current collector can form fine irregularities on its surface to strengthen the bonding strength with the positive electrode active material, and can be used in various forms such as a film, sheet, foil, mesh, net, porous body, foam, and non-woven fabric.

[0064] The solid electrolyte included in the positive electrode of the present invention is identical to the solid electrolyte described above.

[0065] The above positive electrode active material may optionally include a conductive material and a binder.

[0066] The above positive electrode active material may vary depending on the type of all-solid-state battery. For example, the positive electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; chemical formula Li 1+x Mn 2-x O4(0 <x≤0.33), LiMnO3, LiMn2O3, LiMnO2등의 리튬 망간 산화물; 리튬 구리 산화물(Li2CuO2); LiV3O8, V2O5, Cu2V2O7등의 바나듐 산화물; 화학식 LiNi 1-x M x Ni-site lithium nickel oxide represented by O2 (M = Co, Mn, Al, Cu, Fe, Mg, B or Ga; 0.01≤x≤0.3); chemical formula LiMn 2-x M x Lithium manganese composite oxides expressed as O2 (M = Co, Ni, Fe, Cr, Zn or Ta; 0.01≤x≤0.1) or Li2Mn3MO8 (M = Fe, Co, Ni, Cu or Zn); LiNi x Mn 2-x Lithium manganese composite oxide with spinel structure represented by O4; LiCoPO4; LiFePO4; Elemental sulfur (S8); Li2S n (n=1), organosulfur compounds or carbon-sulfur polymers (C2S x ) n : It may include sulfur series compounds such as x=2.5 ~ 50, n=2), but is not limited to these.

[0067] The above conductive material is a material that electrically connects the electrolyte and the positive electrode active material and serves as a path for electrons to move from the current collector to the positive electrode active material. Any material that does not cause chemical changes in a lithium secondary battery and has porosity and conductivity can be used without restriction.

[0068] For example, the conductive material may be a porous carbon-based material, such as carbon black, graphite, graphene, activated carbon, carbon fiber, etc.; metallic fibers such as metal mesh; metallic powders such as copper, silver, nickel, aluminum, etc.; or organic conductive materials such as polyphenylene derivatives. The conductive materials may be used alone or in combination.

[0069] Current commercially available products include acetylene black series (such as those from Chevron Chemical Company or Gulf Oil Company), Ketjen Black EC series (from Armak Company), Vulcan XC-72 (from Cabot Company), and Super P (from MMM). Examples include acetylene black, carbon black, and graphite.

[0070] In addition, the positive electrode may additionally include a binder, and the binder increases the bonding strength between the components constituting the positive electrode and between them and the current collector, and any binder known in the art may be used.

[0071] For example, the binder may be a fluororesin binder including polyvinylidenefluoride (PVdF) or polytetrafluoroethylene (PTFE); a rubber binder including styrene butadiene rubber (SBR), acrylonitrile-butidiene rubber, and styrene-isoprene rubber; a cellulose binder including carboxyl methyl cellulose (CMC), starch, hydroxy propyl cellulose, and regenerated cellulose; a polyalcohol binder; a polyolefin binder including polyethylene and polypropylene; a polyimide binder; a polyester binder; and a silane binder. One, two or more mixtures or copolymers selected from the group consisting of may be used.

[0072]

[0073] A negative electrode according to one embodiment of the present invention may include a negative electrode current collector, a negative electrode active material, and a solid electrolyte.

[0074] The above-mentioned negative electrode, like the above-mentioned positive electrode, may include a conductive material and a binder as needed. In this case, the negative electrode current collector, conductive material, and binder may be those commonly used in the negative electrode, as described above.

[0075] According to one embodiment of the present invention, the negative active material may be in the form of lithium metal, lithium alloy, or negative electrode free.

[0076] The above negative electrode-free form may be a structure including only a negative electrode collector, or a structure in which a carbon layer including a binder is coated on the negative electrode collector.

[0077]

[0078] Those skilled in the art will appreciate that the present invention can be implemented in modified forms without departing from the essential characteristics of the above-described description. Therefore, the disclosed methods should be considered illustrative rather than restrictive. The scope of the present invention is set forth in the claims, not the foregoing description, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

[0079] Hereinafter, preferred examples are presented to help understand the present invention, but the following examples are provided only to make it easier to understand the present invention and the present invention is not limited thereto.

[0080] Example

[0081] After manufacturing a cell with a pressure-sensitive paper as shown in Fig. 4, a test was conducted to apply pressure using a hydraulic press as in the present invention.

[0082] The results are shown in Fig. 5, and it was confirmed that the hand hydraulic press can be used to pressurize close to the desired pressure, and that the pressure is applied uniformly throughout the cell.

[0083] Specifically, as illustrated in Fig. 2, the hand hydraulic press comprises two jigs (a first jig and a second jig) and respective cylinders connected to the jigs. First, the cylinder connected to the first jig has an area of ​​71.15 cm. 2 , the cylinder travel distance per pumping was 0.13 mm, and 7 cm * 7 cm (4,900 mm) 2 ) the pressure applied to the first jig with an area of ​​1 bar increased by 1 bar per pumping. Similarly, the area of ​​the cylinder connected to the second jig was 33.2 cm 2 , the cylinder travel distance per pumping was 1.1 mm, and 8 cm * 10 cm (8,000 mm) 2) The pressure applied to the second jig having an external area of ​​100 mm was increased by 5 bar per pumping.

[0084] In this way, the all-solid-state battery pressurization system of the present invention can operate multiple hydraulic presses that apply different pressures by only controlling one hydraulic cylinder, by connecting the plurality of hydraulic presses through multiple hydraulic connection pipes from one hydraulic cylinder.

[0085] After this, after pressurizing the all-solid-state battery, it was confirmed that the same pressure was applied in the thickness direction of the cell through the pressure relief plates on the upper, middle, and lower surfaces, and this is shown in Fig. 5.

[0086] Through this, it was found that the all-solid-state battery pressurization system of the present invention has the effect of increasing the charge / discharge efficiency of the cell, improving the rate performance of the cell, and improving the charge / discharge cycle of the cell, by applying uniform pressure to the cell even when the cell area increases.

[0087] [Explanation of symbols]

[0088] 11: Jig

[0089] 12: Jig

[0090] 21: Hydraulic press

[0091] 22: Hydraulic press

[0092] 30: Hydraulic cylinder

[0093] 31: Hydraulic connector

[0094] 32: Hydraulic connector

[0095] 40: Gauge

[0096] 50: Manual valve

[0097] 60: Manual pump

Claims

1. A jig for pressurizing the solid-state battery up and down; and A hydraulic press for applying uniform pressure to the above jig; An all-solid-state battery pressurizing system in which a constant pressure is applied to a jig by the pressure applied from the above hydraulic press.

2. In paragraph 1, Containing a plurality of the above jigs, An all-solid-state battery pressurization system, wherein the above plurality of jigs have different areas in contact with the all-solid-state battery.

3. In paragraph 2, An all-solid-state battery pressurization system, wherein the plurality of jigs are each pressurized by a plurality of hydraulic presses, and the plurality of hydraulic presses are connected from a single hydraulic cylinder through a plurality of hydraulic connection pipes.

4. In paragraph 3, The above plurality of jigs include a first jig and a second jig, The area of ​​the above first jig is 6,000 mm 2 Below is the following, The area of ​​the above second jig is 6,000 mm 2 An all-solid-state battery pressurization system that is in excess.

5. In paragraph 4, The above first jig adjusts the pressure in units of 0.5 to 3 bar, An all-solid-state battery pressurization system, wherein the second jig controls the pressure in units of 3 to 8 bar.

6. In paragraph 1, When a certain pressure is applied to the jig by the pressure applied from the above hydraulic press, the thickness of the solid-state battery is reduced. An all-solid-state battery pressurization system that maintains pressure by tightening the screws of a jig.

7. In paragraph 6, After tightening the screw of the above jig to maintain the pressure applied to the solid-state battery, An all-solid-state battery pressurization system that removes pressure applied from a hydraulic press.

8. In paragraph 1, An all-solid-state battery pressurization system, wherein the above-mentioned all-solid-state battery is a sulfide-based all-solid-state battery.

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