Enhanced solid state battery cell

An enhanced solid state battery cell is disclosed. The battery cell can include a first electrode, a second electrode, and a solid state electrolyte layer interposed between the first electrode and the second electrode. The battery cell can further include a resistive layer interposed between the first electrode and the second electrode. The resistive layer can be electrically conductive in order to regulate an internal current flow within the battery cell. The internal current flow can result from an internal short circuit formed between the first electrode and the second electrode. The internal short circuit can be formed from the solid state electrolyte layer being penetrated by metal dendrites formed at the first electrode and/or the second electrode.

TECHNICAL FIELD

The subject matter described herein relates generally to battery technology and more specifically to battery electrolytes.

BACKGROUND

Electrolytes are highly conductive substances that enable the movement of electrically charged ions. For example, electrolytes in a battery can provide a pathway for the transfer of charged particles and/or ions between the anode and the cathode of the battery.

SUMMARY

Systems, methods, and articles of manufacture, including batteries and battery components, are provided. In some implementations of the current subject matter, there is provided a battery cell. The battery cell can include a first electrode, a second electrode, and a solid state electrolyte layer interposed between the first electrode and the second electrode. The battery cell can further include a resistive layer interposed between the first electrode and the second electrode. The resistive layer can be electrically conductive in order to regulate an internal current flow within the battery cell. The internal current flow can result from an internal short circuit formed between the first electrode and the second electrode. The internal short circuit can be formed from the solid state electrolyte layer being penetrated by metal dendrites formed at the first electrode and/or the second electrode.

In some variations, one or more features disclosed herein including the following features can optionally be included in any feasible combination. The resistive layer can further be ionically conductive to enable a transfer of ions between the first electrode and the second electrode.

In some variations, the resistive layer can include one or more electrically conductive materials. The one or more electrically conductive materials can include carbon black, carbon nano tubes, graphene, conductive polymers, and/or conductive inorganic compounds. An amperage of the internal current flow can be proportional to a quantity of the one or more electrically conductive material.

In some variations, the resistive layer can include one or more ionically conductive materials. The one or more ionically conductive materials can include a polymer electrolyte, a polymer gel electrolyte, and/or a solid state electrolyte. A power of the battery cell can be directly proportional to a quantity of the one or more ionically conductive material.

In some variations, the resistive layer can include one or more polymer binders. The one or more polymer binders can include a polyvinylidene fluoride (PVDF), a styrene-butadiene (SBR), a carboxymethyl cellulose (CMC), a polyimide, a polyamide, and/or a polyethylene.

In some variations, the resistive layer can include one or more nano-particle fillers. The one or more nano-particle fillers can include a calcium carbonate (CaCO3), a silicon titanium oxide (SiTiO3), an aluminum oxide (Al2O3), and/or a fumed silica.

In some variations, the resistive layer can include one or more electrochemically active compounds. The one or more electrochemically active compounds can include lithium nickel cobalt (NCM), lithium iron fluorine oxide (LiFeFO2), iron fluoride (FeFx/C), and/or lithium nickel manganese cobalt oxide (NMC).

In some variations, the resistive layer can be interposed between the solid state electrolyte layer and one of the first electrode and the second electrode. The battery cell can further include a first polymer electrolyte layer. The first polymer electrolyte layer can be interposed between the first electrode and the solid state electrolyte layer. The first polymer electrolyte layer can be configured to reduce a contact impedance between the first electrode and the solid state electrolyte layer. The battery cell can further include a second polymer electrolyte layer. The second polymer electrolyte layer can be interposed between the resistive layer and the second electrode. The battery cell can further include a base film layer. The solid state electrolyte layer can be interposed between the first polymer electrolyte layer and the base film layer. The first polymer electrolyte layer and the base film layer can be configured to prevent a decomposition of the solid state electrolyte layer during a production and/or an operation of the battery cell.

In some variations, the battery cell can be a metal battery. The metal battery can be a lithium (Li) battery, a sodium (Na) battery, and/or a potassium (K) battery. The solid state electrolyte layer can be formed by vapor deposition and/or plasma deposition.

DESCRIPTION

Metal batteries, such as lithium (Li) batteries, are susceptible to internal shorts, which can lead to hazardous thermal runaway and combustion. For example, the charging and discharging of a metal battery can give rise to metal dendrites. These metal dendrites can penetrate the porous separator between the anode and the cathode of the metal battery, thereby causing an internal short. Solid state electrolytes (SSEs) are not porous and are thought to be less prone to being penetrated by metal dendrites. Nevertheless, metal dendrites may still penetrate the structural defects, such as pinholes and cracks, that are inevitably present in solid state electrolytes. Thus, a metal battery formed with solid state electrolytes may still succumb to an internal short, particularly after the metal battery is subjected to a large number of charge and discharge cycles. As such, in some implementations of the current subject matter, a battery cell having a solid state electrolyte may further include an electrical barrier against internal shorts. For example, this enhanced solid state battery cell can include a resistive layer configured to regulate internal current flow in the event of an internal short caused by a breach of the solid state electrolyte.

FIG. 1depicts a schematic diagram illustrating a battery cell100consistent with some implementations of the current subject matter. Referring toFIG. 1A, the battery cell100can include a solid state electrolyte layer110, a polymer electrolyte layer120, a base film layer130, a first electrode140A, and a second electrode140B. In some implementations of the current subject matter, the first electrode140A can be the negative electrode (e.g., anode) of the battery cell100. Meanwhile, the second electrode140B can be the positive electrode (e.g., cathode) of the battery cell100. However, it should be appreciated that the battery cell100can also be configured with an opposite electrical polarity.

The solid state electrolyte layer110can be interposed between the polymer electrolyte layer120and the base film layer130. Furthermore, as shown inFIG. 1A, the polymer electrolyte layer120can be interposed between the solid state electrolyte layer110and the first electrode140A while the base film layer130can be interposed between the solid state electrolyte layer110and the second electrode140B. It should be appreciated that the solid state electrolyte layer110may be formed from solid state electrolytes that tend to be fragile and highly reactive. For example, the solid state electrolyte layer110can decompose and/or breakdown during production of the battery cell100due to reaction with common environmental elements such as water and/or oxygen. The solid state electrolyte layer110can also decompose and/or breakdown during operation of the battery cell100by reacting with the first electrode140A and the second electrode140B of the battery cell100upon contact. Thus, in some implementations of the current subject matter, the polymer electrolyte layer120and the base film layer130can be configured to isolate the solid state electrolyte layer110from environmental elements as well as both the first electrode140A and the second electrode140B, thereby preventing a decomposition and/or breakdown of the solid state electrolyte layer110during both the production and operation of the battery cell100. Furthermore, the polymer electrolyte layer120and/or the base film layer130can also mitigate the high contact impedance between the solid state electrolyte layer110and the first electrode140A and/or between the first solid state electrolyte layer110and the second electrode140B.

As noted earlier, the solid state electrolyte layer110can include physical defects (e.g., pinholes, cracks) that render the solid state electrolyte layer110susceptible to being penetrated by metal dendrites, especially after the battery cell100is subjected to a large number of charge and discharge cycles. For example, metal dendrites forming on the first electrode140A and/or the second electrode140B can penetrate the solid state electrolyte layer110, the polymer electrolyte layer120, and the base film layer130to form an internal short circuit160between the first electrode140A and the second electrode140B.FIG. 1Bdepicts a schematic diagram illustrating the internal short circuit160consistent with some implementations of the current subject matter. This internal short circuit160provides an alternative path that is less resistive than a path through an electric load150of the battery cell170. Thus, the bulk of the current170is diverted from the electric load150to the internal short circuit160. The resulting short circuit current165flowing through the battery cell100(e.g., from the second electrode140B to the first electrode140A) can be much greater than the current170still flowing through the electric load150. This short circuit current165can generate a large quantity of heat (e.g., thermal runaway) within the battery cell100that can lead to combustion of the battery cell100. No existing mechanisms are available to mitigate the effects of the internal short circuit160caused by the penetration of the solid state electrolyte layer110.

FIG. 2Adepicts a schematic diagram illustrating a battery cell200consistent with implementations of the current subject matter. Referring toFIG. 2A, the battery cell200can include a solid state electrolyte layer210, a polymer electrolyte layer220, a base film layer230, a resistive layer240, a first electrode250A, and a second electrode250B. In some implementations of the current subject matter, the first electrode250A can be the negative electrode (e.g., anode) of the battery cell200. Meanwhile, the second electrode250B can be the positive electrode (e.g., cathode) of the battery cell200.

The solid state electrolyte layer210can be interposed between the polymer electrolyte layer220and the base film layer230and/or the resistive layer240. For example, as shown inFIG. 2A, the solid state electrolyte layer210can be interposed between the polymer electrolyte layer220and the base film layer230while the polymer electrolyte layer220is interposed between the first electrode250A and the solid state electrolyte layer210. Furthermore, the polymer electrolyte layer220can be interposed between the solid state electrolyte layer210and the first electrode250A. Meanwhile the base film layer230and/or the resistive layer240can be interposed between the solid state electrolyte layer210and the second electrode250B. However, it should be appreciated that the base film layer230can be optional. In the absence of the base film layer230, the solid state electrolyte layer210can also be interposed directly between the polymer electrolyte layer220and the resistive layer240. Furthermore, the positions of the various layers of the battery cell200shown inFIG. 2Aare interchangeable. For example, the respective positions of the polymer electrolyte layer220and the base film layer230can be swapped such that the base film layer230is interposed between the first electrode250A and the solid state electrolyte layer210instead of the polymer electrolyte layer220. Alternately and/or additionally, the respective positions of the base film layer230and the resistive layer240can be swapped such that the base film layer230is interposed between the resistive layer240and the second electrode250B instead of the resistive layer240being interposed between the base layer230and the second electrode250B.

It should be appreciated that the solid state electrolyte layer210may be formed from solid state electrolytes that tend to be fragile and highly reactive. For example, the solid state electrolyte layer210can decompose and/or breakdown during production of the battery cell200due to reaction with common environmental elements such as water and/or oxygen. The solid state electrolyte layer210can also decompose and/or breakdown during operation of the battery cell200by reacting with the first electrode250A and the second electrode250B of the battery cell200upon contact. Thus, in some implementations of the current subject matter, the polymer electrolyte layer220, the base film layer230, and/or the resistive layer240can be configured to isolate the solid state electrolyte layer210from environmental elements as well as both the first electrode250A and the second electrode250B, thereby preventing a decomposition and/or breakdown of the solid state electrolyte layer210during both the production and operation of the battery cell200. Furthermore, the polymer electrolyte layer220, the base film layer230, and/or the resistive layer240can also mitigate the high contact impedance between the solid state electrolyte layer210and the electrode250A and/or between the first solid state electrolyte layer210and the second electrode250B.

As noted earlier, the solid state electrolyte layer210can include physical defects (e.g., pinholes, cracks) that render the solid state electrolyte layer210susceptible to being penetrated by metal dendrites, especially after the battery cell200is subjected to a large number of charge and discharge cycles. For example, metal dendrites forming on the first electrode250A and/or the second electrode250B can penetrate the solid state electrolyte layer210, the polymer electrolyte layer220, the base film layer230, and the resistive layer240to form an internal short circuit270between the first electrode250A and the second electrode250B.

FIG. 2Bdepicts a schematic diagram illustrating the internal short circuit270consistent with implementations of the current subject matter. According to some implementations of the current subject matter, the resistive layer240can be configured to regulate a short circuit current275between the second electrode250B and the first electrode250A, in the event of a breach of the solid state electrolyte layer210and the formation of the internal short circuit20. The resistive layer240can be ionically conductive, electrically conductive, and/or electrochemically active. The short circuit current275that results from the internal short circuit270within the battery cell200can be controlled via the electrical conductivity and/or electrochemical activity of the resistive layer240. As shown inFIG. 2B, the resistive layer240can provide an electric resistance292. A rate (e.g., amperage) of the short circuit current275can be dependent upon the electric resistance292, which may be directly proportional to a quantity of electrically conductive material and/or electrochemically active material in the resistive layer240. Meanwhile, the resistive layer240will not interfere with the normal operation of the battery cell200because the resistive layer240is ionically conductive and/or electrochemically active, and will therefore not impede the transfer of charged particles and/or ions between the first electrode250A and the second electrode250B. However, it should be appreciated that the resistive layer240can impose some ionic resistance294. Thus, the power of the battery cell200can be dependent upon the ionic conductivity and/or the electrochemical activity of the resistive layer240. For instance, the power of the battery cell200can be directly proportional to a quantity of ionically conductive material and/or electrochemically active in the resistive layer240.

In some implementations of the current subject matter, the resistive layer240can be formed from a polymer binder such as, for example, polyvinylidene fluoride (PVDF), styrene-butadiene (SBR), carboxymethyl cellulose (CMC), polyimide, polyamide, polyethylene, and/or the like. The resistive layer240can include one or more electrically conductive additives such as, for example, carbon black, carbon nano tubes, graphene, a conductive polymer, a conductive inorganic compound, and/or the like. The resistive layer240can further include one or more ionically conductive additives such as, for example, a polymer electrolyte, a polymer gel electrolyte, a solid state electrolyte, and/or the like. Alternately and/or additionally, the resistive layer240can include nano-particle fillers such as, for example, calcium carbonate (CaCO3), silicon titanium oxide (SiTiO3), aluminum oxide (Al2O3), fumed silica, and/or the like. The resistive layer240can also be formed from one or more electrochemically active materials (e.g., lithium nickel cobalt (NCM), lithium iron fluorine oxide (LiFeFO2), lithium nickel manganese cobalt oxide (NMC), iron fluoride (FeFx/C)) and/or compounds having a negative thermal expansion coefficient. It should be appreciated that the resistive layer240can have a thickness between 0.1 to 30 microns (μm) or preferably between 1 to 10 microns. Furthermore, heat generated from electrochemical activity within the resistive layer240can provide an indication of the presence of the internal short circuit270and/or trigger one or more safety mechanisms.

It should be appreciated that the battery cell200can be any type of metal battery including, for example, a lithium (Li) battery, a sodium (Na) battery, a potassium (K) battery, and/or the like. The first electrode240A and/or the second electrode240B of the battery cell200can be formed from any material. For instance, the positive second electrode240B can be formed from lithium nickel cobalt (NCM), lithium iron fluorine oxide (LiFeFO2), lithium nickel manganese cobalt oxide (NMC), and/or the like. The solid state electrolyte layer210can be formed from one or more type of solid state electrolytes including, for example, sulfide-based solid state electrolytes (e.g., Li2S—SiS2—P2S5, Li7P3S11, Li4.34Ge0.73Ga0.24S4), garnet-type lithium ion-conducting oxides (e.g., Li5+xLa3(Zrx, A2−x)O12where 1.4<x<2), ceramic ion conductors (e.g., LISICON) containing the frame work structure SiO4, PO4, and ZnO4, and/or the like. Meanwhile, the base film layer230can be formed from any combinations of one or more solid state electrolytes, silicon oxides, alumina oxides, lithium salts, organic binders, inorganic binders, and/or the like. The base film layer230can be a separator or any combination of separators including, for example, a polyethylene separator (e.g., Asahi® D420), a tri-layer polyolefin separator (e.g., Celgard® 2300), a fiber separator, a non-woven fabric separator, a glass fiber separator, a ceramic separator, and/or the like.

In some implementations of the current subject matter, the polymer electrolyte layer220can be formed a polymers and/or a polymer composite. For example, the polymer electrolyte layer220can be formed from a crosslinked polymer (e.g., containing crosslinking agents such as polyethylene oxide, poly-(bis((methoxyethoxy)ethoxy)phosphazene) (MEEP), single ionic conductor (e.g., lithium (Li) replaced Nafion®), polyhedral oligomeric silsesquioxane (POSS), carboxymethyl cellulose (CMC), methacrylate, and/or the like), a non-crosslinked polymer, a stiff polymer (e.g., polyamide imide (PAI)), a block polymer, a composite of different polymers, and/or the like. Alternately and/or additionally, the protective layer120may be formed from a composite of one or more polymers and at least one additive including, for example, conductive and/or nonconductive ceramic particles, lithium salt particles (e.g., lithium fluoroborate (LiBF4and/or LiPF6), lithium nitrate (LiNO3), lithium bis(fluorosulfonyl)imide, lithium bis(perfluoroethanesulfonyl)imide), lithium metal stabilizers (e.g., vinyl carbonate), ether solvents, and/or the like.

FIG. 3depicts a schematic diagram illustrating a battery cell300consistent with some implementations of the current subject matter. Referring toFIG. 3, the battery cell300can include a first electrode350A, a second electrode350B, a solid state electrolyte layer310, a base film layer330, and a resistive layer340. The first electrode350A can be the negative electrode (e.g., anode) of the battery cell300while the second electrode350B can be the positive electrode (e.g., cathode) of the battery cell300. However, it should be appreciated that the battery cell300can also be configured with an opposite electrical polarity.

In some implementations of the current subject matter, the battery cell300can include more than one polymer electrolyte layers configured to mitigate the high contact impedance with respect to the first electrode350A and/or the second electrode350B. For example, the battery cell300can include a first polymer electrolyte layer320A that is interposed between the first electrode350A and the solid state electrolyte layer310. The battery cell300can also include a second polymer electrolyte layer320B that is interposed between the second electrode350B and the resistive layer340. It should be appreciated that one or both of the first polymer electrolyte320A and the second polymer electrolyte320B may be optional.

In some implementations of the current subject matter, the resistive layer340can be configured to regulate a short circuit current flowing through the battery cell300in the event that metal dendrites formed at the first electrode350A and/or the second electrode350B penetrates the first polymer electrolyte layer320A, the second polymer electrolyte layer320B, the solid state electrolyte layer310, and the base film layer330to form an internal short circuit within the battery cell300. The resistive layer340can be formed from one or more materials that are ionically conductive, electrically conductive, and/or electrochemically active. As such, the short circuit current resulting from the internal short circuit within the battery cell300can be controlled by the electrically conductive and/or electrochemically active material within the resistive layer340. Meanwhile, the resistive layer340will not interfere with the normal operation of the battery cell300because the resistive layer340is ionically conductive and/or electrochemically active, and will therefore not impede the transfer of charged particles and/or ions between the first electrode350A and the second electrode350B. However, it should be appreciated that the resistive layer340can impose some ionic resistance. Therefore, the power of the battery cell300can be dependent upon the ionic conductivity of the resistive layer340including, for example, the ionically conductive and/or electrochemically active material within the resistive layer340.

FIG. 4depicts a flowchart illustrating a process400for manufacturing a battery cell consistent with implementations of the current subject matter. Referring toFIGS. 1A-Band4, the process400can be performed to manufacture a battery cell such as, for example, the battery cell100.

At402, a solid state electrolyte layer can be formed. For example, the solid state electrolyte layer110of the battery cell100can be formed, for example, by vapor deposition and/or plasma deposition. In some implementations of the subject matter, forming the solid state electrolyte layer110can include dissolving, using a high speed mixer, 5 grams of polyethylene oxide (PEO) with 1,000,000 molecular weight into approximately 100 grams of deionized water, thereby forming a polyethylene oxide aqueous solution. Furthermore, 1 gram of lithium nitrate can be mixed into the polyethylene oxide aqueous solution followed by 20 grams of Li7La3Zr2O12(LLZO). The resulting slurry can be coated onto the base film layer130. The base film layer130can be a separator such as, for example, Celgard® 2300 and/or the like. Here, an automatic coating machine can be used to deposit an approximately 20 microns thick coating of the slurry onto the separator at 0.1 meter per minute. The coating of slurry can further be dried using the automatic coating machine with a first heating zone set to 60° C. and a second heating zone set to 80° C.

At404, a polymer electrolyte layer can be formed. For example, the polymer electrolyte layer120of the battery cell100can be formed. In some implementations of the current subject matter, forming the polymer electrolyte layer120can include dissolving, using a high speed mixer, 5 grams of polyethylene oxide (PEO) with 500,000 molecular weight into approximately 50 grams of deionized water, thereby forming a polyethylene oxide aqueous solution. Furthermore, 1 gram of lithium nitrate can be mixed into the polyethylene oxide aqueous solution. The solution can be coated onto the solid state electrolyte layer110formed at operation402. For instance, the coating can be performed using an automatic coating machine at 0.1 meter per minute. The coating can further be dried using the automatic coating machine with a first heating zone set to 60° C. and a second heating zone set to 80° C. It should be appreciated that the resulting polymer electrolyte layer120will interface directly with the negative first electrode140A (e.g., anode) of the battery cell100.

At406, a positive electrode can be formed. For example, the second electrode140B of the battery cell100can be formed. In some implementations of the current subject matter, forming the second electrode140B can include dissolving 10.5 grams of polyvinylidene fluoride (PVDF) into 120 grams of N-methylpyrrolidone (NMP). Furthermore, 9 grams of carbon black can be added to the mixture and mixed for 15 minutes at 6500 revolutions per minute (rpm). A flowable slurry can subsequently be formed by adding 280 grams of LiNi0.5Mn0.3Co0.2O2(NMC) (280 g) to the mixture and mixing for 30 minutes at 6500 revolutions per minute. Additional N-methylpyrrolidone (NMP) can be added to adjust the viscosity of the slurry. The resulting slurry can be coated onto a 15 micron thick layer of aluminum foil using an automatic coating machine. The coating of slurry can further be dried using the automatic coating machine with a first heat zone set to approximately 80° C. and a second heat zone set to approximately 130° C. It should be appreciated that subjecting the slurry to heat can evaporate the N-methylpyrrolidone (NMP) in the slurry. The final dried second electrode140B can have a loading of approximately 15.55 milligrams per square centimeter (mg/cm2). The second electrode140B can further be compressed to a thickness of approximately 117 microns.

At408, a battery cell can be prepared. For example, the battery cell100can be formed. In some implementations of the current subject matter, forming the battery cell100can include using an electrode tab to punch out the pieces forming the first electrode140A and/or the second electrode140B. The second electrode140B (e.g., positive electrode) can be dried at 125° C. for 10 hours. Furthermore, the first electrode140A and the second electrode140B can be laminated, in a dry room, with the solid state electrolyte layer110interposed between the first electrode140A, the polymer electrolyte layer120, the base film layer130, and the second electrode140B. It should be appreciated that in the resulting jelly-flat, the polymer electrolyte layer120will directly interface with the first electrode140A while the base film layer130will interface directly with the second electrode140B. This jelly-flat can be inserted into an aluminum (Al) composite bag, which is subsequently filled with a limited quantity of a liquid electrolyte such as, for example, a LiPF6based organic carbonate electrolyte. The aluminum composite bag can be sealed at 190° C. to form the battery cell100. The battery cell100can be aged at 45° C. for 5 hours before being subject to an initial charge and discharge cycle. For instance, the sealed battery cell100can be first charged to 4.2V at a C/20 rate for 5 hours and then to 4.2V at 0.2 C rate for 5 hours before the battery cell100is rested for 20 minutes. The rested battery cell100can subsequently be discharged to 2.8V at 0.2 C rate. In addition, the battery cell100can be punctured, while under vacuum, to release any gases before the battery cell100is resealed. At this point, the battery cell100is ready for operation and/or evaluation.

FIG. 5depicts a flowchart illustrating a process500for manufacturing a battery cell consistent with implementations of the current subject matter. Referring toFIGS. 2A-Band5, the process500can be performed to manufacture a battery cell such as, for example, the battery cell200.

At502, a solid state electrolyte layer can be formed. For example, the solid state electrolyte layer210of the battery cell200can be formed, for example, by vapor deposition and/or plasma deposition. In some implementations of the subject matter, forming the solid state electrolyte layer110can include dissolving, using a high speed mixer, 5 grams of polyethylene oxide (PEO) with 1,000,000 molecular weight into approximately 100 grams of deionized water, thereby forming a polyethylene oxide aqueous solution. Furthermore, 1 gram of lithium nitrate can be mixed into the polyethylene oxide aqueous solution followed by 20 grams of Li7La3Zr2O12(LLZO). The resulting slurry can be coated onto the base film layer230. The base film layer230can be a separator such as, for example, Celgard® 2300 and/or the like. Here, an automatic coating machine can be used to deposit an approximately 20 microns thick coating of the slurry onto the separator at 0.1 meter per minute. The coating of slurry can further be dried using the automatic coating machine with a first heating zone set to 60° C. and a second heating zone set to 80° C.

At504, a resistive layer can be formed on top of a base film. For example, the resistive layer240can be formed on top of the base film layer230. In some implementations of the current subject matter, forming the resistive layer240can include dissolving 10 grams of polyvinylidene fluoride (PVDF) LBG-1 into 100 grams of acetone and 20 grams of N-methylpyrrolidone (NMP). Furthermore, 0.5 grams of carbon black can be added to the mixture and mixed for 15 minutes at 6500 revolutions per minute. A flowable slurry can be formed by adding 1 grams of a lithium salt (e.g., lithium imide) and mixing for 30 minutes at 6500 revolutions per minute. Additional N-methylpyrrolidone (NMP) may be added to adjust the viscosity of the flowable slurry. This resulting slurry can be coated, using an automatic coating machine, onto one side of the base film layer230(e.g., Celgard® 2300) with the solid state electrolyte layer210being disposed on the opposite side of the base film layer230. The automatic coating machine can further be used to dry the slurry with a first heat zone set to approximately 60° C. and a second heat zone set to approximately 80° C. It should be appreciated that the slurry is subjected to heat in order to evaporate off the acetone and the N-methylpyrrolidone (NMP) in the slurry. The final dried resistive layer240can have a loading of approximately 2 milligrams per square centimeter.

At506, a polymer electrolyte layer can be formed. For example, the polymer electrolyte layer220of the battery cell200can be formed. In some implementations of the current subject matter, forming the polymer electrolyte layer220can include dissolving, using a high speed mixer, 5 grams of polyethylene oxide (PEO) with 500,000 molecular weight into approximately 50 grams of deionized water, thereby forming a polyethylene oxide aqueous solution. Furthermore, 1 gram of lithium nitrate can be mixed into the polyethylene oxide aqueous solution. The solution can be coated onto the solid state electrolyte layer210formed at operation502. For instance, the coating can be performed using an automatic coating machine at 0.1 meter per minute. The coating can further be dried using the automatic coating machine with a first heating zone set to 60° C. and a second heating zone set to 80° C. It should be appreciated that the resulting polymer electrolyte layer220will interface directly with the negative first electrode250A (e.g., anode) of the battery cell200.

At508, a positive electrode can be formed. For example, the second electrode250B of the battery cell200can be formed. In some implementations of the current subject matter, forming the second electrode250B can include dissolving 10.5 grams of polyvinylidene fluoride (PVDF) into 120 grams of N-methylpyrrolidone (NMP). Furthermore, 9 grams of carbon black can be added to the mixture and mixed for 15 minutes at 6500 revolutions per minute (rpm). A flowable slurry can subsequently be formed by adding 280 grams of LiNi0.5Mn0.3Co0.2O2(NMC) (280 g) to the mixture and mixing for 30 minutes at 6500 revolutions per minute. Additional N-methylpyrrolidone (NMP) can be added to adjust the viscosity of the slurry. The resulting slurry can be coated onto a 15 micron thick layer of aluminum foil using an automatic coating machine. This coating of slurry can further be dried using the automatic coating machine with a first heat zone set to approximately 80° C. and a second heat zone set to approximately 130° C. It should be appreciated that subjecting the slurry to heat can evaporate the N-methylpyrrolidone (NMP) in the slurry. The final dried second electrode250B can have a loading of approximately 15.55 milligrams per square centimeter (mg/cm2). The second electrode250B can further be compressed to a thickness of approximately 117 microns.

At510, a battery cell can be prepared. For example, the battery cell200can be formed. In some implementations of the current subject matter, forming the battery cell200can include using an electrode tab to punch out the pieces forming the first electrode250A and/or the second electrode250B. The second electrode250B (e.g., positive electrode) can be dried at 125° C. for 10 hours. Furthermore, the first electrode250A and the second electrode250B can be laminated, in a dry room, with the solid state electrolyte layer210interposed between the first electrode250A, the polymer electrolyte layer220, the base film layer230, the resistive layer240, and the second electrode250B. It should be appreciated that in the resulting jelly-flat, the polymer electrolyte layer220will directly interface with the first electrode250A while the resistive layer240will interface directly with the second electrode250B. This jelly-flat can be inserted into an aluminum (Al) composite bag, which is subsequently filled with a limited quantity of a liquid electrolyte such as, for example, a LiPF6based organic carbonate electrolyte. The aluminum composite bag can be sealed at 190° C. to form the battery cell200. The battery cell200can be aged at 45° C. for 5 hours before being subject to an initial charge and discharge cycle. For instance, the sealed battery cell200can be first charged to 4.2V at a C/20 rate for 5 hours and then to 4.2V at 0.2 C rate for 5 hours before the battery cell200is rested for 20 minutes. The rested battery cell200can subsequently be discharged to 2.8V at 0.2 C rate. In addition, the battery cell200can be punctured, while under vacuum, to release any gases before the battery cell200is resealed. At this point, the battery cell200is ready for operation and/or evaluation.

FIG. 6depicts a flowchart illustrating a process600for manufacturing a battery cell consistent with implementations of the current subject matter. Referring toFIGS. 2A-Band6, the process600can be performed to manufacture a battery cell such as, for example, the battery cell200.

At602, a solid state electrolyte layer can be formed. For example, the solid state electrolyte layer210of the battery cell200can be formed, for example, by vapor deposition and/or plasma deposition. In some implementations of the subject matter, forming the solid state electrolyte layer110can include dissolving, using a high speed mixer, 5 grams of polyethylene oxide (PEO) with 1,000,000 molecular weight into approximately 100 grams of deionized water, thereby forming a polyethylene oxide aqueous solution. Furthermore, 1 gram of lithium nitrate can be mixed into the polyethylene oxide aqueous solution followed by 20 grams of Li7La3Zr2O12(LLZO). The resulting slurry can be coated onto the base film layer230. The base film layer230can be a separator such as, for example, Celgard® 2300 and/or the like. Here, an automatic coating machine can be used to deposit an approximately 20 microns thick coating of the slurry onto the separator at 0.1 meter per minute. The coating of slurry can further be dried using the automatic coating machine with a first heating zone set to 60° C. and a second heating zone set to 80° C.

At604, a polymer electrolyte layer can be formed. For example, the polymer electrolyte layer220of the battery cell200can be formed. In some implementations of the current subject matter, forming the polymer electrolyte layer220can include dissolving, using a high speed mixer, 5 grams of polyethylene oxide (PEO) with 500,000 molecular weight into approximately 50 grams of deionized water, thereby forming a polyethylene oxide aqueous solution. Furthermore, 1 gram of lithium nitrate can be mixed into the polyethylene oxide aqueous solution. The solution can be coated onto the solid state electrolyte layer210formed at operation502. For instance, the coating can be performed using an automatic coating machine at 0.1 meter per minute. The coating can further be dried using the automatic coating machine with a first heating zone set to 60° C. and a second heating zone set to 80° C. It should be appreciated that the resulting polymer electrolyte layer220will interface directly with the negative first electrode250A (e.g., anode) of the battery cell200.

At606, a positive electrode can be formed. For example, the second electrode250B of the battery cell200can be formed. In some implementations of the current subject matter, forming the second electrode250B can include dissolving 10.5 grams of polyvinylidene fluoride (PVDF) into 120 grams of N-methylpyrrolidone (NMP). Furthermore, 9 grams of carbon black can be added to the mixture and mixed for 15 minutes at 6500 revolutions per minute (rpm). A flowable slurry can subsequently be formed by adding 280 grams of LiNi0.5Mn0.3Co0.2O2(NMC) (280 g) to the mixture and mixing for 30 minutes at 6500 revolutions per minute. Additional N-methylpyrrolidone (NMP) can be added to adjust the viscosity of the slurry. The resulting slurry can be coated onto a 15 micron thick layer of aluminum foil using an automatic coating machine. This coating of slurry can further be dried using the automatic coating machine with a first heat zone set to approximately 80° C. and a second heat zone set to approximately 130° C. It should be appreciated that subjecting the slurry to heat can evaporate the N-methylpyrrolidone (NMP) in the slurry. The final dried second electrode250B can have a loading of approximately 15.55 milligrams per square centimeter (mg/cm2). The second electrode250B can further be compressed to a thickness of approximately 117 microns.

At608, a resistive layer can be formed on top of the positive electrode. For example, the resistive layer240can be formed on top of the positive second electrode250B instead of the base film layer230as in process500. In some implementations of the current subject matter, forming the resistive layer240can include dissolving 10 grams of polyvinylidene fluoride (PVDF) LBG-1 into 100 grams of acetone and 20 grams of N-methylpyrrolidone (NMP). Furthermore, 0.5 grams of carbon black can be added to the mixture and mixed for 15 minutes at 6500 revolutions per minute. A flowable slurry can be formed by adding 1 grams of a lithium salt (e.g., lithium imide) and mixing for 30 minutes at 6500 revolutions per minute. Additional N-methylpyrrolidone (NMP) may be added to adjust the viscosity of the flowable slurry. This resulting slurry can be coated, using an automatic coating machine, onto one side of the second electrode250B (e.g., Celgard® 2300) formed at operation606. The automatic coating machine can further be used to dry this coating of slurry with a first heat zone set to approximately 60° C. and a second heat zone set to approximately 80° C. It should be appreciated that the slurry is subjected to heat in order to evaporate off the acetone and the N-methylpyrrolidone (NMP) in the slurry. The final dried resistive layer240can have a loading of approximately 2 milligrams per square centimeter.

At610, a battery cell can be prepared. For example, the battery cell200can be formed. In some implementations of the current subject matter, forming the battery cell200can include using an electrode tab to punch out the pieces forming the first electrode250A and/or the second electrode250B. The second electrode250B (e.g., positive electrode) can be dried at 125° C. for 10 hours. Furthermore, the first electrode250A and the second electrode250B can be laminated, in a dry room, with the solid state electrolyte layer210interposed between the first electrode250A, the polymer electrolyte layer220, the base film layer230, the resistive layer240, and the second electrode240B. It should be appreciated that in the resulting jelly-flat, the polymer electrolyte layer220will directly interface with the first electrode250A while the resistive layer240will interface directly with the second electrode250B. This jelly-flat can be inserted into an aluminum (Al) composite bag, which is subsequently filled with a limited quantity of a liquid electrolyte such as, for example, a LiPF6based organic carbonate electrolyte. The aluminum composite bag can be sealed at 190° C. to form the battery cell200. The battery cell200can be aged at 45° C. for 5 hours before being subject to an initial charge and discharge cycle. For instance, the sealed battery cell200can be first charged to 4.2V at a C/20 rate for 5 hours and then to 4.2V at 0.2 C rate for 5 hours before the battery cell200is rested for 20 minutes. The rested battery cell200can subsequently be discharged to 2.8V at 0.2 C rate. In addition, the battery cell200can be punctured, while under vacuum, to release any gases before the battery cell200is resealed. At this point, the battery cell200is ready for operation and/or evaluation.

FIG. 7depicts a flowchart illustrating a process700for manufacturing a battery cell consistent with implementations of the current subject matter. Referring toFIGS. 3 and 7, the process700can be performed to manufacture a battery cell such as, for example, the battery cell300.

At702, a solid state electrolyte layer can be formed. For example, the solid state electrolyte layer310of the battery cell300can be formed, for example, by vapor deposition and/or plasma deposition. In some implementations of the subject matter, forming the solid state electrolyte layer310can include dissolving, using a high speed mixer, 5 grams of polyethylene oxide (PEO) with 1,000,000 molecular weight into approximately 100 grams of deionized water, thereby forming a polyethylene oxide aqueous solution. Furthermore, 1 gram of lithium nitrate can be mixed into the polyethylene oxide aqueous solution followed by 20 grams of Li7La3Zr2O12(LLZO). The resulting slurry can be coated onto the base film layer330. The base film layer330can be a separator such as, for example, Celgard® 2300 and/or the like. Here, an automatic coating machine can be used to deposit an approximately 20 microns thick coating of the slurry onto the separator at 0.1 meter per minute. The coating of slurry can further be dried using the automatic coating machine with a first heating zone set to 60° C. and a second heating zone set to 80° C.

At704, a first polymer electrolyte layer can be formed. For example, the first polymer electrolyte layer320A of the battery cell300can be formed. In some implementations of the current subject matter, forming the first polymer electrolyte layer320can include dissolving, using a high speed mixer, 5 grams of polyethylene oxide (PEO) with 500,000 molecular weight into approximately 50 grams of deionized water, thereby forming a polyethylene oxide aqueous solution. Furthermore, 1 gram of lithium nitrate can be mixed into the polyethylene oxide aqueous solution. The solution can be coated onto the solid state electrolyte layer310formed at operation702. For instance, the coating can be performed using an automatic coating machine at 0.1 meter per minute. This coating of slurry can further be dried using the automatic coating machine with a first heating zone set to 60° C. and a second heating zone set to 80° C. It should be appreciated that the resulting first polymer electrolyte layer320A will interface directly with the negative first electrode350A (e.g., anode) of the battery cell300.

At706, a resistive layer can be formed on top of a base film layer. For example, the resistive layer340can be formed on top of the base film layer330. In some implementations of the current subject matter, forming the resistive layer340can include dissolving 10 grams of polyvinylidene fluoride (PVDF) LBG-1 into 100 grams of acetone and 20 grams of N-methylpyrrolidone (NMP). Furthermore, 0.5 grams of carbon black can be added to the mixture and mixed for 15 minutes at 6500 revolutions per minute. A flowable slurry can be formed by adding 1 grams of a lithium salt (e.g., lithium imide) and mixing for 30 minutes at 6500 revolutions per minute. Additional N-methylpyrrolidone (NMP) may be added to adjust the viscosity of the flowable slurry. This resulting slurry can be coated, using an automatic coating machine, onto one side of the base film layer330(e.g., Celgard® 2300) with the solid state electrolyte layer310being disposed on the opposite side of the base film layer330. The automatic coating machine can further be used to dry this coating of slurry with a first heat zone set to approximately 60° C. and a second heat zone set to approximately 80° C. It should be appreciated that the slurry is subjected to heat in order to evaporate off the acetone and the N-methylpyrrolidone (NMP) in the slurry. The final dried resistive layer340can have a loading of approximately 2 milligrams per square centimeter.

At708, a second polymer electrolyte layer can be formed on top of the resistive layer. For example, the second polymer electrolyte layer320B of the battery cell300can be formed on top of the resistive layer340. In some implementations of the current subject matter, forming the second polymer electrolyte layer320B can include dissolving, using a high speed mixer, 5 grams of polyethylene oxide (PEO) with 500,000 molecular weight into approximately 50 grams of deionized water, thereby forming a polyethylene oxide aqueous solution. Furthermore, 1 gram of lithium nitrate can be mixed into the polyethylene oxide aqueous solution. The solution can be coated onto one side of the resistive layer340formed at operation706, opposite from the base film layer330. For instance, the coating can be performed using an automatic coating machine at 0.1 meter per minute. This coating of slurry can further be dried using the automatic coating machine with a first heating zone set to 60° C. and a second heating zone set to 80° C. It should be appreciated that the resulting second polymer electrolyte layer320B will interface directly with the positive second electrode350B (e.g., cathode) of the battery cell300.

At710, a positive electrode can be formed. For example, the second electrode350B of the battery cell300can be formed. In some implementations of the current subject matter, forming the second electrode250B can include dissolving 10.5 grams of polyvinylidene fluoride (PVDF) into 120 grams of N-methylpyrrolidone (NMP). Furthermore, 9 grams of carbon black can be added to the mixture and mixed for 15 minutes at 6500 revolutions per minute (rpm). A flowable slurry can subsequently be formed by adding 280 grams of LiNi0.5Mn0.3Co0.2O2(NMC) (280 g) to the mixture and mixing for 30 minutes at 6500 revolutions per minute. Additional N-methylpyrrolidone (NMP) can be added to adjust the viscosity of the slurry. The resulting slurry can be coated onto a 15 micron thick layer of aluminum foil using an automatic coating machine. This coating of slurry can further be dried using the automatic coating machine with a first heat zone set to approximately 80° C. and a second heat zone set to approximately 130° C. It should be appreciated that subjecting the slurry to heat can evaporate the N-methylpyrrolidone (NMP) in the slurry. The final dried second electrode350B can have a loading of approximately 15.55 milligrams per square centimeter (mg/cm2). The second electrode350B can further be compressed to a thickness of approximately 117 microns.

At712, a battery cell can be prepared. For example, the battery cell300can be formed. In some implementations of the current subject matter, forming the battery cell300can include using an electrode tab to punch out the pieces forming the first electrode350A and/or the second electrode350B. The second electrode350B (e.g., positive electrode) can be dried at 125° C. for 10 hours. Furthermore, the first electrode350A and the second electrode350B can be laminated, in a dry room, with the solid state electrolyte layer310interposed between the first electrode350A, the first polymer electrolyte layer320A, the base film layer330, the resistive layer340, the second polymer electrolyte layer320B, and the second electrode350B. It should be appreciated that in the resulting jelly-flat, the first polymer electrolyte layer320A will directly interface with the first electrode350A while the second polymer electrolyte layer320B will interface directly with the second electrode350B. Meanwhile, the base film layer330is interposed between the solid state electrolyte layer310and the resistive layer340. This jelly-flat can be inserted into an aluminum (Al) composite bag, which is subsequently filled with a limited quantity of a liquid electrolyte such as, for example, a LiPF6based organic carbonate electrolyte. The aluminum composite bag can be sealed at 190° C. to form the battery cell300. The battery cell300can be aged at 45° C. for 5 hours before being subject to an initial charge and discharge cycle. For instance, the sealed battery cell300can be first charged to 4.2V at a C/20 rate for 5 hours and then to 4.2V at 0.2 C rate for 5 hours before the battery cell300is rested for 20 minutes. The rested battery cell300can subsequently be discharged to 2.8V at 0.2 C rate. In addition, the battery cell300can be punctured, while under vacuum, to release any gases before the battery cell300is resealed. At this point, the battery cell300is ready for operation and/or evaluation.

Implementations of the current subject matter can include, but are not limited to, articles of manufacture (e.g. apparatuses, systems, etc.), methods of making or use, compositions of matter, or the like consistent with the descriptions provided herein.

The subject matter described herein can be embodied in systems, apparatus, methods, and/or articles depending on the desired configuration. The implementations set forth in the foregoing description do not represent all implementations consistent with the subject matter described herein. Instead, they are merely some examples consistent with aspects related to the described subject matter. Although a few variations have been described in detail above, other modifications or additions are possible. In particular, further features and/or variations can be provided in addition to those set forth herein. For example, the implementations described above can be directed to various combinations and subcombinations of the disclosed features and/or combinations and subcombinations of several further features disclosed above. In addition, the processes depicted in the accompanying figures and/or described herein do not necessarily require the operations to be performed in the order shown, or in any sequential order, in order to achieve desirable results. For example, one or more operations from these processes may be repeated and/or omitted. Other implementations may be within the scope of the following claim.