All-solid-state battery pressurization system

Abstract

The invention relates to an all-solid-state battery pressurizing system, which comprises a clamp, a pressurizing device and a pressurizing device, wherein the clamp is used for vertically pressurizing an all-solid-state battery; and a hydraulic machine for applying a uniform pressure to the jig, wherein the uniform pressure is applied to the jig by the pressure applied by the hydraulic machine.

Description

Technical Field

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

[0002] This invention relates to a pressurization system for all-solid-state batteries. Background Technology

[0003] A secondary battery is a device that converts external electrical energy into chemical energy, stores it, and generates electricity when needed. It is also known as a rechargeable battery because it can be recharged multiple times. Common secondary batteries include lead-acid batteries, nickel-cadmium (NiCd) batteries, nickel-metal hydride (NiMH) batteries, and lithium-ion batteries. Secondary batteries offer superior economic and environmental benefits compared to primary batteries, which are discarded after a single use.

[0004] On the other hand, as wireless communication technologies become increasingly advanced, the demand for lightweight, thin, and miniaturized portable devices and automotive accessories is increasing, leading to a growing need for secondary batteries as the energy source for these devices. In particular, as hybrid and electric vehicles become more practical in terms of environmental protection, research is emerging on using secondary batteries in these next-generation automotive batteries to reduce manufacturing costs and weight while extending their lifespan. Among various secondary batteries, lithium-ion batteries have recently gained attention due to their light weight, high energy density and operating potential, and long cycle life.

[0005] Lithium-ion batteries are typically manufactured by mounting an electrode laminate consisting of a negative electrode, a positive electrode, and a separator inside a cylindrical or angular metal can or a bag-shaped housing of aluminum laminates and injecting electrolyte into the electrode laminate.

[0006] Traditionally, liquid electrolytes in which lithium salts are dissolved in non-aqueous organic solvents have been used in lithium secondary batteries. However, these liquid electrolytes are not only prone to electrode material degradation and organic solvent volatilization, but also susceptible to combustion or explosion due to increased ambient temperature and the battery's own temperature, and are prone to leakage, making it difficult to achieve highly safe lithium secondary batteries of various types.

[0007] On the other hand, all-solid-state batteries that utilize solid electrolytes have the advantage of eliminating organic solvents, which allows for safe and simple electrode laminates.

[0008] Based on the raw materials of the solid electrolyte, all-solid-state batteries can be divided into oxide-based, polymer-based, and sulfide-based batteries. Sulfide-based all-solid-state batteries have attracted attention due to their superior lithium-ion conductivity compared to other types of batteries. However, despite their excellent characteristics, they exhibit higher ionic conductivity and resistance between the positive and negative electrodes than liquid batteries, resulting in lower lifespan and output compared to batteries utilizing conventional liquid electrolytes.

[0009] On the other hand, secondary batteries are manufactured through processes of assembling battery cells and activating the batteries, in which the battery cells are mounted on a charging and discharging device such as a fixture and charged and discharged to the conditions required for activation. In this way, the process of using a fixture to perform predetermined charging and discharging to activate the battery is called formation.

[0010] Because all-solid-state batteries are rechargeable, they also undergo this charging and discharging process, which requires applying pressure to the battery using clamps. Currently, torque wrenches are used to tighten the clamp screws one by one to apply pressure to the battery, but this method does not provide uniform pressure to the battery. Furthermore, as the cell area increases, greater pressure is required. However, relying solely on screw tightening methods without a pressing device has its limitations.

[0011] Therefore, it is necessary to study an all-solid-state battery pressurization system that can apply uniform pressure to the entire area of ​​the cell in order to solve the above problems.

[0012] (Patent Reference 1) U.S. Patent Application Publication No. 2023-0028855 Summary of the Invention

[0013] Technical issues

[0014] The purpose of this invention is to provide a pressurization system for all-solid-state batteries, which can apply uniform pressure to the entire area of ​​the battery cell during the all-solid-state battery charging and discharging process.

[0015] Technical solution

[0016] To achieve the above objectives, the present invention provides an all-solid-state battery pressurization system, comprising:

[0017] A clamp for vertically pressurizing an all-solid-state battery; and a hydraulic press for applying uniform pressure to the clamp; wherein uniform pressure is applied to the clamp by pressure applied by the hydraulic press.

[0018] In one example of the invention, the all-solid-state battery pressurization system includes a plurality of clamps, wherein the plurality of clamps may have different areas of contact with the all-solid-state battery.

[0019] In one example of the invention, each of the plurality of clamps is pressurized by a plurality of hydraulic presses, wherein the plurality of hydraulic presses may be connected to a single hydraulic cylinder via a plurality of hydraulic connecting pipes.

[0020] In one example of the present invention, the plurality of clamps includes a first clamp and a second clamp, wherein the area of ​​the first clamp is 6000 mm². 2 Or smaller, and the area of ​​the second clamp is greater than 6000 mm². 2 .

[0021] In one example of the invention, the first clamp can adjust the pressure in units of 0.5 bar to 3 bar, and the second clamp can adjust the pressure in units of more than 3 bar to up to 8 bar.

[0022] In one example of the invention, when the thickness of the all-solid-state battery is reduced by applying a constant pressure to the clamp through the pressure applied by the hydraulic press, the pressure can be maintained by tightening the screws of the clamp.

[0023] In one example of the invention, pressure applied to the all-solid-state battery is maintained by tightening the screws of the clamp, and then the pressure applied by the hydraulic press is removed.

[0024] In one example of the invention, pressure applied to the all-solid-state battery is maintained by tightening the screws of the clamp, and then the pressure applied by the hydraulic press is removed.

[0025] In one example of the present invention, the all-solid-state battery may be a sulfide-based all-solid-state battery.

[0026] Beneficial effects

[0027] The pressurization system of the all-solid-state battery of the present invention has the effect of applying uniform pressure to the cell even when the cell area is increased, thereby improving the cell's charge and discharge efficiency, improving the cell's rate performance, and improving the cell's charge and discharge cycle. Attached Figure Description

[0028] Figure 1 The image shows a pressurization system for all-solid-state batteries based on existing technology.

[0029] Figure 2 This is a schematic diagram illustrating a pressurization system for an all-solid-state battery according to an example of the present invention.

[0030] Figure 3 This is a schematic diagram illustrating a pressurization system for an all-solid-state battery according to an example of the present invention.

[0031] Figure 4This is a schematic diagram illustrating a bag manufactured by pressurizing an all-solid-state battery according to an example of the present invention.

[0032] Figure 5 This is an image showing the result of pressurizing an all-solid-state battery according to an example of a pressurization system based on an all-solid-state battery, according to an invention. Detailed Implementation

[0033] The invention will now be described in detail with reference to the accompanying drawings, which will enable those skilled in the art to readily practice it. However, the invention can be implemented in many different forms and is not limited to the examples described herein.

[0034] To clearly illustrate the invention, parts irrelevant to the description have been omitted, and identical or similar parts are indicated by the same reference numerals in the specification.

[0035] Furthermore, the terms and words used in this specification and claims should not be interpreted in their ordinary or dictionary sense, but rather in the sense and concept consistent with the technical concept of the invention, based on the principle that the inventors may define the concepts of terms as they deem appropriate to best describe their invention.

[0036] Examples will now be described in detail with reference to the accompanying drawings. However, the invention can be implemented in many different forms and is not limited to the examples described herein.

[0037] In traditional all-solid-state batteries, all-solid-state batteries using sulfide-based solid electrolytes undergo charging and discharging processes, during which pressure must be applied to the battery via clamps. Traditionally, such as Figure 1 As shown, the method of tightening the screws of the clamp one by one with a torque wrench is used for pressurizing the battery cell. However, this method is not only cumbersome, but also has the disadvantage of not being able to apply uniform pressure to the battery cell. In addition, as the area of ​​the battery cell increases, greater pressure needs to be applied, but relying solely on the screw tightening method without a stamping device has its limitations.

[0038] Therefore, it is necessary to study an all-solid-state battery pressurization system that can apply uniform pressure to the entire area of ​​the cell in order to solve the above problems.

[0039] Therefore, the inventors of this invention discovered that an all-solid-state battery pressurization system can solve the above-mentioned problems, and thus completed this invention, the all-solid-state battery pressurization system comprising:

[0040] A clamp for vertically pressurizing an all-solid-state battery; a hydraulic press for applying uniform pressure to the clamp, wherein uniform pressure is applied to the clamp by pressure applied by the hydraulic press.

[0041] This invention relates to an all-solid-state battery pressurization system, which particularly includes:

[0042] A clamp for vertically pressurizing an all-solid-state battery; and a hydraulic press for applying uniform pressure to the clamp.

[0043] The all-solid-state battery pressurization system of the present invention can apply constant pressure to the clamp by applying pressure from a hydraulic press, thereby applying constant pressure to the top and bottom of the all-solid-state battery.

[0044] The all-solid-state battery pressurization system of the present invention includes multiple clamps, wherein the multiple clamps may have different contact areas with the all-solid-state battery, such as... Figure 2 As shown. The all-solid-state battery pressurization system of the present invention utilizes multiple clamps of different areas, so that the pressure applied to the clamps can be different.

[0045] In an all-solid-state battery pressurization system, when the thickness of the all-solid-state battery is reduced by applying constant pressure to the fixture using pressure applied by a hydraulic press, the pressure can be maintained by tightening the screws in the fixture. When the hydraulic press applies pressure to the fixture, the screws in the fixture are loosened, and the pressure applied by the hydraulic press can be maintained by tightening the loosened screws accordingly.

[0046] In the all-solid-state battery pressurization system of the present invention, the pressure applied to the all-solid-state battery is maintained by tightening the screws of the clamp, and then the pressure applied by the hydraulic press is removed. As mentioned above, when the screws are tightened, the pressure applied by the hydraulic press can be maintained, and 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 clamp can be maintained.

[0047] In this invention, each of the plurality of clamps is pressurized by a plurality of hydraulic presses, and the plurality of hydraulic presses can be connected to a single hydraulic cylinder 30 through a plurality of hydraulic connecting pipes 31, 32, such as Figure 3 As shown. For each of the clamps 11 and 12, a hydraulic press 21 or 22 is arranged, which applies pressure on one side of the clamp 11 or 12, and thus also applies pressure to the all-solid-state battery. The means for applying pressure to the hydraulic press 21 or 22 is a hydraulic cylinder 30. In this invention, the hydraulic cylinder 30 applies pressure to the multiple hydraulic presses 21 or 22 via multiple hydraulic connecting pipes 31 or 32, wherein one of the hydraulic presses 21 or 22 is connected to the multiple hydraulic connecting pipes 31 or 32, and the hydraulic connecting pipes 31 or 32 are in turn connected to the multiple hydraulic presses 21 or 22, thereby applying pressure to the multiple clamps 11 or 12.

[0048] In this invention, only one hydraulic cylinder 30 exists, but the pressure applied to the clamps 11 and 12 can vary depending on the different areas of the clamps 11 and 12 to which they are connected. Each pumping action of the hydraulic cylinder 30 causes the cylinder to move a certain amount of stroke, which is defined as the stroke distance. Thus, each pumping action has a constant stroke distance, thereby allowing a constant pressure value to be added. This stroke distance will depend on the pressure in the cylinder; for example, if the cylinder area is 71.15 cm². 2 If the cylinder travels 0.13 mm per pump stroke, then the pressure applied to the clamp with an external area of ​​7 cm x 7 cm will increase by 1 bar per pump stroke. Similarly, if the cylinder area is 33.2 cm²... 2 If the cylinder pumps forward 1.1 mm (13 bar or less) or 0.28 mm (13 bar or more) each time, the pressure on the clamp with an external area of ​​8 cm * 10 cm increases by 5 bar each time.

[0049] The pressure applied to the clamp can be changed by altering its area (outer width). Therefore, in this invention, when multiple clamps include a first clamp and a second clamp, the first clamp can be configured to have a width of 6000 mm. 2 Or a smaller area, and the second clamp can be set to have a diameter of more than 6000 mm. 2 The area.

[0050] In this case, the first clamp in the all-solid-state battery pressurization system of the present invention can adjust the pressure in units of 0.5 to 3 bar, and the second clamp can adjust the pressure in units of more than 3 to up to 8 bar.

[0051] The pressure can be regulated using a meter 40, a manual valve 50, and a manual pump 60, and the meter, valve, and pump can be any of those commonly used in the art.

[0052] In this invention, the all-solid-state battery pressurized by the all-solid-state battery pressurization system may include a positive electrode, a negative electrode, and a solid electrolyte. It may also include a positive electrode lead and a negative electrode lead, respectively connected to the positive and negative electrodes.

[0053] All-solid-state batteries can be pouch-type battery cells, in which the positive electrode, negative electrode, and solid electrolyte are embedded in a pouch, with a portion of the positive and negative leads exposed outside the pouch. Pouch-type battery cells can be manufactured by placing the solid electrolyte between the positive and negative electrodes, pressurizing it to bond the layers, and then enclosing and sealing the electrode assembly formed by attaching the positive and negative leads within the pouch.

[0054] However, the structure of the all-solid-state battery pressurized by an all-solid-state battery pressurization system according to an example of the present invention is not limited to this configuration.

[0055] The configuration of the positive electrode, negative electrode, solid electrolyte layer, positive electrode lead, negative electrode lead and pouch included in the all-solid-state battery can be used without any specific limitations, as long as it is used in all-solid-state batteries used in the art, but preferably it can be a sulfide-based all-solid-state battery.

[0056] In this invention, the all-solid-state battery can be a sulfide-based all-solid-state battery. Therefore, the positive electrode, negative electrode, and solid electrolyte layer included in the all-solid-state battery of this invention can contain a sulfide-based solid electrolyte.

[0057] Sulfide-based solid electrolytes contain sulfur (S) and exhibit ionic conductivity belonging to Group 1 or Group 2 metals of the periodic table, and may comprise Li-PS-based glasses or Li-PS-based glass ceramics. Non-limiting examples of such sulfide-based solid electrolytes may 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, and Li₂S-GeS₂-ZnS, and may include one or more of these electrolytes. However, they are not specifically limited to these examples.

[0058] The solid electrolyte layer of the present invention can be prepared from a sulfide-based solid electrolyte. The method for forming the solid electrolyte layer is not particularly limited, as long as it is used in the art, and can be, for example, by mixing solid electrolyte powder with a binder and a solvent to prepare a slurry containing a sulfide-based solid electrolyte, then applying the slurry to a current collector on which electrodes are formed, drying, and calendering the slurry. The binders and solvents that can be used are not particularly limited, as long as they are materials that do not react with the sulfur in the solid electrolyte.

[0059] According to one example of the present invention, the positive electrode may include a positive electrode current collector, a positive electrode active material, and a solid electrolyte.

[0060] The positive electrode current collector is used to support the positive electrode active material and is not particularly limited, as long as it has good conductivity and is electrochemically stable within the voltage range of the lithium secondary battery. For example, the positive electrode current collector can be any metal selected from the group consisting of copper, aluminum, stainless steel, titanium, silver, palladium, nickel, their alloys, and combinations thereof, wherein the stainless steel can be surface-treated with carbon, nickel, titanium, or silver, and the alloy can preferably be an aluminum-cadmium alloy, but it can also be a non-conductive polymer with a surface treated with calcined carbon or a conductive material, or it can be a conductive polymer.

[0061] The positive electrode current collector can form micro-protrusions and depressions on its surface to strengthen the bonding force with the positive electrode active material, and various forms can be used, such as films, sheets, foils, grids, meshes, porous bodies, foams, non-woven fabrics, etc.

[0062] The solid electrolyte contained in the positive electrode of the present invention is the same as the above solid electrolyte.

[0063] The positive electrode active material can include a positive electrode active material and optionally a conductive material and a binder.

[0064] The positive electrode active material can vary according to the type of all-solid-state battery. For example, the positive electrode active material can include, but is not limited to: layered compounds, such as lithium cobalt oxide ((LiCoO2), or lithium nickel oxide (LiNiO2), or a compound substituted by one or more transition metals; lithium manganese oxide, such as Li 1+x Mn 2-x O4 (where 0 < x ≤ 0.33), LiMnO3, LiMn2O3 or LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxide, such as LiV3O8, V2O5, or Cu2V2O7; LiNi 1-x M x O2 represented Ni-site type lithium nickel compound (where M is Co, Mn, Al, Cu, Fe, Mg, B or Ga; and 0.01 ≤ x ≤ 0.3); lithium manganese composite oxide represented by LiMn 2-x M x O2 (where M is Co, Ni, Fe, Cr, Zn or Ta; and 0.01 ≤ x ≤ 0.1) or Li2Mn3MO8 (where M is Fe, Co, Ni, Cu or Zn); lithium manganese composite oxide with spinel structure represented by LiNi x Mn 2-x O4; LiCoPO4; LiFePO4; elemental sulfur (S8); sulfur-based compounds, such as Li2Sn (where n is 1), organic sulfur compounds or carbon sulfur polymers ((C2S x )n, where x is 2.5 to 50, and n is 2).

[0065] The 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, and can be used without limitation as long as it does not cause chemical changes in the lithium secondary battery and has porosity and conductivity.

[0066] For example, porous carbon-based materials can be used as conductive materials, including carbon black, graphite, graphene, activated carbon, and carbon fibers; metal fibers, such as metal mesh; metal powders, such as copper, silver, nickel, or aluminum; or organic conductive materials, such as polyphenylene derivatives. Conductive materials can be used alone or in combination.

[0067] Currently available commercially available conductive materials include acetylene black (from Chevron Chemical Company or Gulf Oil Company), Ketjen Black EC (from Armak Company), Vulcan XC-72 (from Cabot Company), and Super P (from MMM). Examples may include acetylene black, carbon black, and graphite.

[0068] Furthermore, the positive electrode may further include an adhesive, wherein the adhesive further increases the cohesive force between the components comprising the positive electrode or between the components and the current collector, and any adhesive known in the art may be used.

[0069] For example, the adhesive may be a mixture or copolymer of one or more of the following: fluoroplastic adhesives including polyvinylidene fluoride (PVdF) or polytetrafluoroethylene (PTFE); rubber-based adhesives including styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber or styrene-isoprene rubber; cellulose adhesives including carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose and regenerated cellulose; polyol adhesives; polyolefin adhesives including polyethylene or polypropylene; polyimide adhesives; polyester adhesives; and silane adhesives.

[0070] According to one example of the invention, the negative electrode may include a negative electrode current collector, a negative electrode active material, and a solid electrolyte.

[0071] Like the positive electrode, the negative electrode can contain conductive materials and binders as needed. As mentioned above, the negative electrode current collector, conductive materials, and binders can be those commonly used for negative electrodes.

[0072] According to one example of the invention, the negative electrode active material may be lithium metal, lithium alloy, or a negative electrode-free form.

[0073] The negative electrode-less form may consist only of a negative electrode current collector, or it may be a structure in which a carbon layer containing an adhesive is coated on the negative electrode current collector.

[0074] Those skilled in the art will understand that this example can be implemented in modified forms without departing from the basic features described above. Therefore, the disclosed method should be considered illustratively rather than restrictively. The scope of the invention is shown by the patent claims rather than by the foregoing description, and all differences within its scope should be construed as incorporated herein.

[0075] Mode of implementing the present invention

[0076] The following examples are provided to illustrate the invention. The invention is not limited thereto.

[0077] Example

[0078] In such Figure 4 After the battery cell with pressure-sensitive paper is manufactured as shown, it is tested by applying pressure using a hydraulic press as described in this invention.

[0079] The result is Figure 5 As shown, and confirmed, the use of a manual hydraulic press allows for the precise application of the desired pressure and ensures uniform pressure throughout the cell.

[0080] Specifically, such as Figure 2 As shown, the manual hydraulic press includes two clamps (a first clamp and a second clamp) and corresponding cylinders connected to the respective clamps. Firstly, the cylinder connected to the first clamp has an area of ​​71.15 cm². 2 The pumping stroke distance of the cylinder is 0.13mm per stroke, and the area of ​​the cylinder connected to the first clamp is 7cm*7cm (4900mm). 2 Each pumping operation increases the pressure applied to the first clamp by 1 bar. Similarly, the area of ​​the cylinder connected to the second clamp is 33.2 cm². 2 Furthermore, the pumping stroke distance of the cylinder is 1.1mm per stroke, and the area of ​​the cylinder connected to the second clamp is 8cm*10cm (8000mm²). 2 Each pumping operation increases the pressure applied to the second clamp by 5 bar.

[0081] In this way, the multiple hydraulic presses of the all-solid-state battery pressurization system of the present invention are connected to a single hydraulic cylinder through multiple hydraulic connecting pipes, so that multiple hydraulic presses applying different pressures can be operated by simply adjusting a single hydraulic cylinder.

[0082] After pressurizing the all-solid-state battery, it was found that applying the same pressure in the thickness direction of the battery through pressure-sensitive paper at the top, middle, and bottom resulted in the following effect: Figure 5 As shown.

[0083] It can be seen that even with a larger cell area, the all-solid-state battery pressurization system of the present invention can still apply uniform pressure to the cell, thereby improving the cell's charge and discharge efficiency, rate performance, and charge and discharge cycle performance.

[0084] [Figure Label] 11: Fixture

[0085] 12: Fixture

[0086] 21: Hydraulic Press

[0087] 22: Hydraulic press

[0088] 30: Hydraulic cylinder

[0089] 31: Hydraulic connecting pipe; 32: Hydraulic connecting pipe; 40: Measuring device

[0090] 50: Manual valve

[0091] 60: Manual pump

Claims

1. A solid-state battery pressurization system, the solid-state battery pressurization system comprising: A clamp that applies vertical pressure to the all-solid-state battery; as well as A hydraulic press, used to apply uniform pressure to the clamp; A constant pressure is applied to the clamp by pressure applied by the hydraulic press.

2. The all-solid-state battery pressurization system according to claim 1, The all-solid-state battery pressurization system includes multiple clamps. in, The contact areas between the multiple clamps and the all-solid-state battery are different.

3. The all-solid-state battery pressurization system according to claim 2, in, Each of the plurality of clamps is pressurized by a plurality of hydraulic presses. The plurality of hydraulic presses are connected to a single hydraulic cylinder via a plurality of hydraulic connecting pipes.

4. The all-solid-state battery pressurization system according to claim 3, in, The plurality of clamps includes a first clamp and a second clamp. The area of ​​the first fixture is 6000 mm². 2 or smaller, and The area of ​​the second fixture exceeds 6000 mm². 2 .

5. The all-solid-state battery pressurization system according to claim 4, in, The first clamp adjusts the pressure in units of 0.5 bar to 3 bar, and the second clamp adjusts the pressure in units of more than 3 bar to up to 8 bar.

6. The all-solid-state battery pressurization system according to claim 1, in, When reducing the thickness of the all-solid-state battery by applying a constant pressure to the clamp through the pressure applied by the hydraulic press, the pressure is maintained by tightening the screws of the clamp.

7. The all-solid-state battery pressurization system according to claim 6, in, The pressure applied to the all-solid-state battery is maintained by tightening the screws of the clamp, and then the pressure applied by the hydraulic press is removed.

8. The all-solid-state battery pressurization system according to claim 1, in, The all-solid-state battery is a sulfide-based all-solid-state battery.

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