Multi-cell monolithic thin film battery and method for manufacturing the same

Abstract

The disclosed invention consists of a multi-cell monolithic thin-film battery (0) in which two or more monolithic battery cells, each comprising a cathode current collector (20), a cathode electrode layer (21), a solid electrolyte layer (22), and an anode current collector (23), are stacked on top of each other on a single-layer substrate (1). All of the monolithic battery cells (2, 2') have a thickness of 10 nm or more and 20 μm or less and are manufactured by a thin-film technology that does not use an anode layer, and thus are referred to as monolithic anode-free battery cells (2, 2'). It is based on an implementable method for improving characteristics and joining multiple cells to form a stacked thin-film battery. The disclosed invention is achieved by stacking all of the layers of the resulting multi-cell monolithic thin-film battery (0) on top of each other on a single-layer substrate (1), and laminating a blocking layer as a layer of a material that blocks electrons and ions between the cathode current collector (20) and the anode current collector (23) of each adjacent monolithic anode-free battery cell (2, 2'), setting the stacking thickness of the blocking layer to 5 nm or more and 1 μm or less, and laminating the first layer of the next adjacent monolithic anode-free battery cell (2') on top of the last layer of the immediately preceding monolithic anode-free battery cell (2).

Description

Technical Field

[0001] The present invention describes a multi-cell monolithic thin-film battery including two or more monolithic battery cells each having one substrate on which a cathode current collector, a cathode electrode layer, a solid electrolyte layer, and an anode current collector are stacked on one another, and a method for manufacturing the same.

Background Art

[0002] There is an increasing demand for energy storage technologies for efficiently utilizing environmentally friendly and sustainable energy sources. Solid lithium-ion batteries based on non-flammable or flame-retardant solid electrolytes have attracted significant attention because of their improved safety compared to conventional Li-ion batteries. As described in "All-solid-state lithium-ion and lithium-metal batteries - paving the way to large-scale production, Journal of Power Sources, Vol. 382, April 1, 2018, pp. 160-175", thin-film multi-cell batteries based on Li metal are also known as prior art.

[0003] Currently, Li-metal-based solid cells and solid batteries are fabricated using Li metal foil or PVD-deposited Li metal. However, using Li metal in solid batteries is unrealistic from a fabrication perspective and may prevent final commercialization. Especially for Li foil, a passive film is formed on the surface of Li metal even in a dry room, making it difficult to handle and requiring an argon atmosphere to avoid high interfacial resistance. Anode-free solid batteries solve this problem by removing the anode from the manufacturing process. However, even in single-cell batteries, the non-uniform growth of Li metal at the interface between the current collector and the solid electrolyte is one of the major problems in such anode-free batteries.

[0004] Several attempts have been made to manufacture multi-cell monolithic thin-film batteries comprising a plurality of battery cells. In a stable monolithic battery cell, an anode electrode layer, a solid electrolyte layer, and a cathode electrode layer can be laminated in layers on a substrate, but it has been found that it is difficult to monolithically bond individual cells or to stably operate such a multi-cell laminate.

[0005] U.S. Patent Application Publication No. 2012 / 270114 is known, and a thin-film battery provided with an anode layer is disclosed. The substrate is considered to be optional, and it is only possible to speculate about laminating the cells of U.S. Patent Application Publication No. 2012 / 270114. For example,

[0045] describes that "the substrate 200 is optionally provided." However, the substrate is an important element for the function of the battery. Also, a conductive barrier 250 is disposed between two adjacent cells, but if this is a true conductive barrier, the battery will not function. U.S. Patent Application Publication No. 2012 / 270114 does not show an implementable method for monolithically bonding individual cells, other than the fact of using an anode layer, and this method is very important for the function of the cells.

[0006] European Patent No. 3261157 also does not introduce an anode-free cell or a method of monolithically bonding individual cells sufficiently stably and firmly.

[0007] U.S. Patent No. 9543564 introduces an anode-free cell, and since the anode layer is not fabricated during the fabrication of the cell, U.S. Patent No. 9543564 represents the closest state of the art. However, the problem of stably bonding individual cells has not been fully solved. SUMMARY OF THE INVENTION

[0008] The object of the present invention is to create a multi-cell monolithic thin-film battery with improved characteristics and mechanical and electrical stability, based on an implementable method for joining a plurality of cells to form a stacked thin-film battery, where the joining and stacking formation are important for the function of the multi-cell monolithic thin-film battery.

[0009] The object of the present invention is to provide a multi-cell monolithic thin-film battery that has a custom form factor, improved discharge capacity, extremely short charge and discharge times, large discharge capacity, improved thermal management such as no need for cooling, longer cycle life, improved stability to suit high-voltage devices, and can be fabricated more economically and simply.

[0010] The device manufacturing method of the present invention and the device configured thereafter improve the prior art by providing a design for an anode-free multi-cell monolithic thin-film battery, resulting in a high-voltage device with improved discharge capacity, and simplifying the manufacturing process because there is no negative electrode layer / anode layer in the cells to be fabricated.

[0011] The manufacturing method of each cell to be fabricated is of interest to battery manufacturers specializing in Gen4 batteries and Gen5 batteries that use thin-film fabrication technology. Potential applications of Gen4 batteries and Gen5 batteries include high-performance mobile applications such as drones, robots, eVTOL, aerospace, urban transportation, medical devices, and wearables.

Brief Description of the Drawings

[0012]

Fig. 1a

Fig. 1b

Fig. 1c

Fig. 1d

Fig. 2a

Fig. 2b

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DETAILED DESCRIPTION OF THE INVENTION

[0013] By referring to the following detailed description in conjunction with the related drawings described briefly below, various aspects of the present invention can be further understood.

[0014] In embodiments where different descriptions are made, the same parts are given the same reference numerals or the same names, and the same applies to the same parts given the same reference numerals or the same names in the disclosure included in the entire description.

[0015] Preferred exemplary embodiments of the subject matter of the present invention will be described below in conjunction with the accompanying drawings.

[0016] The present invention describes a multi-cell monolithic thin-film battery 0 comprising two or more monolithic stacked anode-free battery cells 2, 2' stacked on a single-layer substrate 1. In a monolithic stacked battery, all the layers of the battery are fabricated on top of each other's upper ends on a single-layer substrate 1.

[0017] Based on the layer of one substrate 1, at least a cathode current collector 20, a cathode electrode layer 21, a solid electrolyte layer 22, and an anode current collector 23 are provided, and two or more monolithic anode-free battery cells 2, 2' without an anode layer are stacked. Using thin-film technology, all layers are stacked within the known thickness range of thin-film technology of 5 nm or more and 20 μm or less.

[0018] The anode-free multi-cell monolithic thin-film battery 0 is a battery without an anode during fabrication. When the multi-cell monolithic thin-film battery 0 is charged, the interface between the anode current collector 23 and the solid electrolyte layer 22 is plated with Li ions, and a Li metal anode is formed. In the case of the anode-free multi-cell monolithic thin-film battery 0, there is no anode during fabrication.

[0019] The stacking order of layers 20 to 23 and the interface between the anode current collector 23 layer of one monolithic anode-free battery cell 2 and the next adjacent monolithic anode-free battery cell 2' when the individual cells are electrically joined in series are shown in the schematic diagram of Fig. 1a.

[0020] In another embodiment of the multi-cell monolithic thin-film battery 0' comprising two or more adjacent monolithic anode-free battery cells 2, 2' according to Fig. 1b, a desired blocking layer B is stacked between the cathode current collector (20) and the anode current collector (23) of the adjacent monolithic anode-free battery cells (2, 2').

[0021] The blocking layer B can change the electron resistance, ion resistance, or both, improve the mechanical properties, and can be removed at specific locations or stacked only at specific locations to adjust the direct electron and / or ion contact between the battery cells 2, 2'. The barrier layer B is defined as a thin layer of material provided between any two adjacent layers to prevent unwanted reactions between the layers. The barrier layer B can be designed to block ions, electrons, or both, preventing unwanted reactions and improving battery performance. The most preferred barrier layer B blocks both electrons and ions, and then it is necessary to partially remove the barrier layer B to create ion or electron contact between adjacent layers.

[0022] The barrier layer B can also be laminated between adjacent individual monolithic anode-free battery cells, or can be repeatedly provided only between a plurality of monolithically laminated battery cells.

[0023] The barrier layer B as an intermediate layer between cells 2 and 2' contains one or more transition metal oxides. The thickness of the barrier layer B is 5 nm or more and 1 μm or less and contains a transition metal oxide.

[0024] The purpose of the barrier layer is to introduce an intermediate layer that changes the electron resistance and / or ion resistance between individual multi-cell monolithic anode-free battery cells 2 and 2'. This layer can also be selectively laminated using a shadow mask, similar to photolithography, to accurately define the contact area between individual monolithic anode-free battery cells 2 and 2', and can be selectively removed by plasma etching. This can simplify the manufacture of multi-cell monolithic anode-free batteries that otherwise require the use of complex manufacturing processes.

[0025] Most preferably, it is the barrier layer B laminated by PVD or the barrier layer B laminated by atomic layer deposition (ALD), a type of chemical vapor deposition (CVD) that increases the electron resistance and / or ion resistance between individual battery cells 2 and 2', which functions as a planarizing layer to eliminate potential non-uniformities and can offset mechanical stresses that may occur during charge and discharge cycles.

[0026] In addition to adding the blocking layer B as an intermediate layer between the individual monolithic anode-free battery cells 2, 2', a blocking layer can also be introduced as an intermediate layer between any adjacent layers of the individual monolithic anode-free battery cells to change the electron resistance and / or ion resistance.

[0027] Also, in the multi-cell monolithic thin-film battery 0'' having precisely defined layers and no anode layer, the result can also be improved by introducing a desired seed layer S between the solid electrolyte layer 22 and the anode current collector 23 of each monolithic anode-free battery cell 2, 2'. This desired seed layer S is laminated by one of the same thin-film lamination techniques as the other layers. The seed layer S increases the number of Li metal nucleation sites at the interface between the anode current collector 23 and the solid electrolyte layer 22 for uniform Li metal plating and peeling. The seed layer S functions as a base for the growth of Li metal during battery charging. The seed layer S can also improve adhesion and reduce resistance between the cathode electrode layer 21 and the cathode current collector 20.

[0028] The desired seed layer S is laminated between the solid electrolyte layer 22 and the anode current collector 23 with a thickness of 1 nm or more and 500 nm or less, and most preferably has a thickness of less than 100 nm.

[0029] The seed layer S contains one or more elements selected from the group consisting of Mg, Ca, Sr, Ru, Rh, Ir, Pd, Pt, Ag, Au, Zn, Cd, Al, Ga, In, Ti, C, Si, Ge, Sn, Pb, P, As, Sb, Bi, S, Se, Te, or a compound containing one or more of these elements, or a compound obtained by adding one or more elements or compounds selected from the group consisting of H, B, N, O, F, Cl, Br, I to these elements.

[0030] The seed layer S most preferably contains one or more atoms selected from the group consisting of Au, Ag, Zn, Mg, Pt, Al, and C, and most preferably contains Au, Ag, and / or C. The seed layer S ensures a flat interface between the individual anode-free cells 2, 2', 2'' and has not been used conventionally in the context of monolithically stacked thin-film batteries 0.

[0031] In addition to increasing the number of nucleation sites by means of a seed layer between the solid electrolyte layer 22 and the anode current collector 23, the number of nucleation sites for Li metal plating in the anode-free battery cell can be increased by short pulses of high current density during pre-cycling or by increasing the current density of short current pulses during charging and discharging of the battery or cell.

[0032] In addition to the above, a combination of the embodiments of FIGS. 1b and 1c was implemented, which also showed good and stable results. A blocking layer B is laminated between each of the cells 2, 2' provided with a seed layer S between the solid electrolyte layer 22 and the anode current collector 23 of the monolithic anode-free battery cells 2, 2'.

[0033] Li metal in a thin-film battery or cell is usually deposited by a PVD process. Since Li metal deposited by a PVD process is generally non-uniform, a plurality of thin-film batteries or cells cannot be stacked on top of each other's upper ends. By not having a lithium metal anode, a single monolithic anode-free battery cell 2, 2' can be stacked in a mechanically and electronically stable and reproducible manner.

[0034] An SEM image of an embodiment of a multi-cell monolithic anode-free thin-film battery 0 according to the schematic diagram of FIG. 1a is shown in FIG. 2a, and the electronic effect of such a device is shown in FIG. 2b in the form of a charge-discharge curve. This has been proven for the first time.

[0035] As shown in Fig. 3, the step of laminating individual monolithic thin-film battery cells 2 to 2' can be carried out to join the layers in parallel. In that case, adjacent battery cells share the cathode current collector 20 or the anode current collector 23. The individual anode current collectors 23 and cathode current collectors 20 are joined, for example, via tabs to electrically join the individual battery cells in parallel. Although the seed layer S and the blocking layer B are not shown here, they are laminated as described above. The seed layer S between the adjacent solid electrolyte layer 22 and the anode current collector 23 and the blocking layer B can be introduced as an intermediate layer between adjacent layers of individual monolithic anode-free battery cells, specifically as an intermediate layer between individual multi-cell monolithic anode-free battery cells 2 and 2'.

[0036] In the SEM cross-section of the 2-cell 2, 2' battery 0'', a seed layer S is disposed between the solid electrolyte layer 22 and the anode current collector 23 of each cell 2, 2'.

[0037] The latter multi-cell monolithic thin-film battery 0 can also be fabricated by a combination of series joining and parallel joining of the layers of each cell 2.

[0038] The substrate 1 to be used may have rigidity or flexibility and is made of a metal, polymer, or glassy material, and most preferably a glass material such as glass / TiN or Si / TiN.

[0039] The cathode current collector 20 includes one or more selected from the group consisting of Al, Au, stainless steel, or alloys thereof. The most preferred material for the cathode current collector 20 is aluminum, and the thickness is most preferably 50 nm or more and 1 μm or less. The Al pellet is evaporated at a rate of 1 nm / min or more and 10 nm / min or less at room temperature.

[0040] The cathode electrode layer 21 is LCO (lithium cobalt oxide), NMC (nickel manganese cobalt oxide), NCA (lithium nickel cobalt aluminum oxide), NMA (nickel manganese aluminum), LFP (lithium iron phosphate), LMO (lithium manganese dioxide), LMNO (lithium manganese nickelate), VO (vanadium oxide), It contains one or more selected from the group consisting of chalcogens, chalcogenides, halogens, and metal halides. The cathode electrode layer 21 is laminated as a thin film with a thickness of 100 nm or more and 20 μm or less, or laminated in the form of particles with a size of 0.01 μm or more and 2 μm or less embedded in a composite matrix, improving ion conductivity and / or electron conductivity and mechanical properties to offset mechanical deformation due to expansion and contraction during charge and discharge cycles.

[0041] The most preferred material for the cathode electrode layer 21 is LCO or NMC, and the thickness is most preferably 100 nm or more and 5 μm or less. In the RF sputtering of LiCoO2, power: 5 - 15 W / cm 2 , gas flow rate: Ar 24 - 60 sccm, O2 0.5 - 1 sccm, pressure: 3 mTorr, speed: 3 - 10 nm / min at room temperature, are applied.

[0042] The solid electrolyte layer 22 contains one or more selected from the group consisting of nitrates, oxides, sulfides, halides, phosphates, borates, hydrides, and polymers. Such a solid electrolyte layer 22 is laminated as a thin film with a thickness of 0.1 μm or more and 5 μm or less. The most preferred material for the solid electrolyte layer 22 is LiPON, an amorphous glass material known as an electrolyte material, i.e., lithium phosphonitride, and its thickness is 300 nm or more and 2 μm or less, most preferably about 1000 nm ± 10%. In the RF co - sputtering with Li2O and Li3PO4 as targets, power: 5 - 10 W / cm 2 (Li3PO4), 5 - 10 W / cm 2 (Li2O), gas flow rate: 25 - 50 sccm (N2), pressure: 3 mTorr, speed: 1 - 2.5 nm / min at room temperature, are applied.

[0043] Each anode current collector 23 contains one or more selected from the group consisting of Cu, Ni, Ti, stainless steel, and their alloys. The most preferable thickness of the anode current collector 23 is 50 nm or more and 1 μm or less. When using Cu, the thickness should be about 100 nm ± 10%.

[0044] Apply the individual layers continuously to the substrate 1 in the order described. All the individual layers are laminated by thin film technologies such as PVD, CVD, dip coating, spin coating, or screen printing.

[0045] After the lamination of the cathode electrode layer 21, the solid electrolyte layer 22, the seed layer S, and the blocking layer B, after the lamination of one monolithic thin film battery, or after the lamination of two or more multi-cell monolithic thin film batteries, if desired, the individual layers can be crystallized in an argon, nitrogen, oxygen atmosphere or in a vacuum at a material temperature of 40 °C or more and 1000 °C or less.

[0046] As disclosed and described in the drawings, the multi-cell monolithic thin film batteries 0, 0’, 0’’, 0’’’ include one substrate 1, on which two or more monolithic battery cells 2, 2’, 2’’ are laminated in order with a cathode current collector 20, a cathode electrode layer 21, a solid electrolyte layer 22, and an anode current collector 23. The order of the layers may be different and reversed, but it is not shown in detail in this specification.

Explanation of Signs

[0047] 0 Multi-cell monolithic thin film battery (More than one cell is joined in series, parallel, or a combination of both) 1 Substrate (one for each multi-cell monolithic thin film battery) 2, 2’, 2’’ Monolithic anode-free battery cells 20 Cathode current collector 21 Cathode electrode layer 22 Solid electrolyte layer S Desired seed layer (list) 23 Anode current collector B Desired blocking layer (intermediate layer)

Claims

1. A multi-cell monolithic thin-film battery (0) is formed in which two or more monolithic battery cells, each comprising a cathode current collector (20), a cathode electrode layer (21), a solid electrolyte layer (22), and an anode current collector (23), are stacked on a single-layer substrate (1), All of the aforementioned monolithic battery cells (2, 2') have a thickness of 10 nm to 20 μm and are manufactured using thin-film technology without an anode layer, and are therefore referred to as monolithic anode-free battery cells (2, 2'). On the single-layer substrate (1), all layers of the multi-cell monolithic thin-film battery (0) are fabricated on each other's upper edges. Between the cathode current collector (20) and the anode current collector (23) of the adjacent monolithic anode-free battery cells (2, 2'), a barrier layer (B) is laminated as a material layer that blocks electrons and ions. The stacking thickness of the stacked barrier layer (B) is 5 nm or more and 1 μm or less. A multi-cell monolithic thin-film battery in which the first layer of the next adjacent monolithic anode-free battery cell (2') is stacked on top of the last layer of the immediately preceding monolithic anode-free battery cell (2).

2. The multi-cell monolithic thin-film battery (0') according to claim 1, wherein the barrier layer (B) is laminated between adjacent layers of any of the adjacent monolithic anode-free battery cells (2, 2').

3. The multi-cell monolithic thin-film battery (0') according to claim 1 or 2, wherein the barrier layer (B) as an intermediate layer contains a metal oxide.

4. A multi-cell monolithic thin-film battery (0'', 0''') according to claim 1 or 2, wherein a seed layer (S) is laminated between the solid electrolyte layer (22) and the anode current collector (23) of each monolithic anode-free battery cell (2) to increase the number of nucleation sites for uniform Li metal plating and peeling.

5. The multi-cell monolithic thin-film battery (0') according to claim 4, wherein the stacking thickness of the seed layer (S) is 1 nm or more and 500 nm or less, most preferably 10 nm or more and 100 nm or less.

6. The multi-cell monolithic thin-film battery (0') according to claim 4, wherein the material of the seed layer (S) contains an atom selected from the group consisting of Au, Ag, Zn, Mg, Pt, Al, and C, most preferably containing Au, Ag, and / or C.

7. The multi-cell monolithic thin-film battery (0) according to claim 1 or 2, wherein the material of the solid electrolyte layer (22) comprises one or more selected from the group consisting of phosphates, borates, oxides, sulfides, halides, hydrides, and polymers, and is laminated as a thin film with a thickness of 0.1 μm or more and 5 μm or less.

8. The multi-cell monolithic thin-film battery (0) according to claim 1 or 2, wherein the anode current collector (23) comprises one or more selected from the group consisting of Cu, Ni, Ti, stainless steel, and alloys thereof, and has a thickness of 50 nm to 1 μm.

9. The multi-cell monolithic thin-film battery (0) according to claim 1 or 2, wherein the cathode current collector (20) contains Al and has a thickness of 50 nm or more and 1 μm or less.

10. A method for manufacturing a multi-cell monolithic thin-film battery (0) comprising two or more monolithic anode-free battery cells (2, 2') on a single-layer substrate (1), In a subsequent thin film lamination process using PVD, CVD, ALD, dip coating, spin coating, or screen printing, monolithic anode-free battery cells (2) are laminated in layers on the substrate (1) with a thickness of 5 nm to 20 μm. Each battery cell (2, 2') consists of a cathode current collector (20), a cathode electrode layer (21), a solid electrolyte layer (22), and an anode current collector (23). Without creating an anode layer, Before stacking the first layer of the next adjacent monolithic anode-free battery cell (2') on top of the last layer of the immediately preceding monolithic anode-free battery cell (2), a barrier layer (B) is stacked between the cathode current collector (20) and the anode current collector (23) of each adjacent monolithic anode-free battery cell (2, 2') as a layer of material that blocks electrons and ions. A manufacturing method wherein the stacking thickness of the barrier layer (B) is 5 nm or more and 1 μm or less.

11. The manufacturing method according to claim 10, wherein a seed layer (S) is laminated between the solid electrolyte layer (22) of each monolithic anode-free battery cell (2, 2') and the adjacent anode current collector (23) using thin-film technology such as PVD, CVD, ALD, dip coating, spin coating, or screen printing to increase the number of nucleation sites for uniform Li metal plating and peeling.

12. The manufacturing method according to claim 10 or 11, wherein the barrier layer (B) is laminated between two adjacent layers of individual monolithic anode-free battery cells (2) using thin-film technology such as PVD, CVD, ALD, dip coating, spin coating, or screen printing.

13. The manufacturing method according to claim 10 or 11, wherein the barrier layer (B) is laminated between the cathode current collector (20) and the anode current collector (23) of two adjacent monolithic anode-free battery cells (2, 2') using thin-film technology such as PVD, CVD, ALD, dip coating, spin coating, or screen printing.

14. The manufacturing method according to claim 10 or 11, wherein the contact area between two adjacent monolithic anode-free battery cells (2, 2') is precisely determined by selectively stacking the barrier layer (B) using a shadow mask or selectively removing it by plasma etching.

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