Novel battery system based on a two-additive electrolyte system containing 2-furanone and method of its formation process

Abstract

To provide methods of preparing battery systems in which gas formation is suppressed.SOLUTION: The battery systems comprise two-additive mixtures in an electrolyte solvent. Such battery systems are prepared by assembling a positive electrode and a negative electrode in a sealed cell, removing residual water from the sealed cell, filling the sealed cell with a nonaqueous electrolyte under an inert atmosphere, vacuum-sealing the sealed cell, carrying out a formation process comprising charging and discharging the sealed cell until the sealed cell achieves an initial capacity. The nonaqueous electrolyte includes lithium ions, a first nonaqueous solvent comprising a carbonate solvent, a second nonaqueous solvent comprising methyl acetate, and an additive mixture of a first operative additive of either vinylene carbonate or fluoroethylene carbonate and a second operative additive of 2-furanone. Gas formation is suppressed in the battery systems during the formation process.SELECTED DRAWING: Figure 7A

Description

[Technical Field]

[0001] The present disclosure relates to rechargeable battery systems, and more particularly to rechargeable lithium-ion battery systems. The synthesis of such systems, including working electrolyte additives and electrodes, to improve system performance. The present disclosure also relates to the manufacture of rechargeable battery cells, and more particularly to the manufacture of post-assembly chemical This document relates to the construction and testing process of rechargeable battery cells. [Background technology]

[0002] Rechargeable batteries are used in electric vehicles and grid storage (e.g., as backup power during power outages). It is an essential component of energy storage systems (e.g., power sources, part of microgrids, etc.) Depending on the application, different characteristics are required from the energy storage system. To create a system suitable for For example, in automotive applications, especially electric vehicle applications, rapid charging and Discharge performance is a key feature of the system. Electric vehicle owners can accelerate quickly through traffic. This requires the ability to quickly discharge the system. Because charging and discharging places demands on the system, the components of the system also need to be able to withstand such motion. The thermal conductivity may need to be selected to provide sufficient longevity under operating conditions.

[0003] The initial charging and discharging of Li-ion cells is done at the factory by the manufacturer. As a result of the formation process, a solid electrolyte interface (SEI) is formed on the anode. A layer of solid-electrolyte interface is created, which is usually The use of a passivation layer is essential to mitigate the charging process This chemical charge / discharge process acts as a charge layer in the battery pack. This can be useful in identifying cells that do not meet quality standards before they are introduced. It is important to minimize gas generation during the process, which leads to process simplification. There is a possibility that

[0004] Furthermore, during the formation process, the cell capacity and open-circuit voltage (OCV) after formation were measured. cuit voltage), direct-current resistance (DCR:direct-current re resistance), and collects information about cell performance such as capacitance and impedance. , quality analysis can be performed. The spread of performance measurements is related to the formation process and upstream cell It can also indicate whether the manufacturing process is in control.

[0005] For high-throughput manufacturing, many cells are placed together in the chemical conversion process, typically on a carrier tray. Conventional mass production equipment typically uses a power module coupled to a battery contact fixture. It consists of a module and control module that holds a tray of cells and connects them to individually controlled cells. Such systems often require many cables (usually batteries) They require four or more wires per cell, take up a lot of space, and are energy inefficient. As a result, inefficiencies due to power electronics and long cables can be This can result in heat being rejected indoors, often through large ducted air cooling systems. This can lead to fluctuations in cell temperature and increase the risk of errors in the formation process. In addition, existing chemical plants typically do not have fully considered and optimized support systems. It is designed without any restrictions.

[0006] Furthermore, the electrolyte additive is operative and can be used in lithium-ion batteries. For example, Non-Patent Document 1 lists five unique Its undisclosed electrolyte additives contain no additives or only one additive. It has been shown to extend cycle life compared to electrolyte systems. As described, improved performance of electrolyte systems containing three or four additives However, researchers typically focus on the electrolyte and specific cathode and anode combinations. Understanding the interactions between various additives that allow them to work together synergistically Therefore, the identity of a particular system is often based on trial and error and cannot be predicted in advance. It is not possible.

[0007] Previous research has focused on combining lithium-ion battery systems for grid or automotive applications. We have identified a dual-additive electrolyte system that can produce a robust system with sufficient properties for this application. As described in US Patent No. 5,649,299, the two-additive system studied (e.g., 2% VC + 1% allyl methanesulfonate and 2% PES + 1% TTSPi) are usually three types and the performance was inferior to that of four additive electrolyte systems (see, for example, Table 1 of Patent Document 1). and Table 2.) Patent Document 1 discloses a method for producing a robust lithium-ion battery system. To achieve this, a third compound, often tris(tris(trimethylsilyl)methyl) is added at a concentration of 0.25% to 3% by weight. Tris(trimethylsilyl)-phosphate (TTSP) or tris(trimethylsilyl)- It is disclosed that a phosphite (TTSPi) was required (for example, Patent Document 1 (See paragraph 72 of the same document.) However, it is expensive and difficult to add to Li-ion batteries on a manufacturing scale. Because it is difficult to include additives, simpler yet effective solutions, including those with fewer additives, are being sought. There is a need for a battery system.

[0008] definition "Cell" or "battery cell" generally refers to an electrochemical cell, which produces electricity from a chemical reaction. To generate energy or to promote chemical reactions through the introduction of electrical energy A battery is a device that can store and store electricity. A battery can contain one or more cells.

[0009] A "rechargeable battery" is generally a battery that can be charged, discharged into a load, and recharged multiple times. This disclosure refers to any type of electrical battery. Some examples have been described based on lithium-ion rechargeable batteries. The disclosed embodiments are not limited to one type of rechargeable battery, but can be used with a variety of rechargeable battery technologies. It can be applied as follows. Summary of the Invention [Means for solving the problem]

[0010] This disclosure provides a method for detecting and storing energy stored in a variety of energy storage applications, such as vehicles and grid storage. This includes novel battery systems that contain less working electrolyte additives. More specifically, This disclosure reduces the amount of gas produced during the formation process, improving the performance and Improve lifespan while simultaneously reducing costs from other systems that rely more heavily on additives This disclosure also relates to the disclosed dual additive electrolyte systems. Effective positive and negative electrodes are disclosed that work together to provide further systematic improvements.

[0011] Two-acting type containing vinylene carbonate (VC) combined with 2-furanone (FN) An additive electrolyte system is disclosed, in which FN has the following formula (I): TIFF0007730871000001.tif45111

[0012] Fluoroethylene carbonate (FEC) in combination with FN is also disclosed.

[0013] VC and FEC provide similar improvements (and are believed to function similarly) Therefore, the mixture of VC and FEC can be considered as a single effective electrolyte. Another disclosed dual acting additive electrolyte system is VC and FEC combined with FN. The larger battery system (including the electrolyte, electrolyte solvent, positive electrode, and negative electrode) When used as part of a vehicle, these dual acting additive electrolyte systems This produces desirable properties for energy storage applications, including power generation.

[0014] More specifically, the cathode is made of lithium nickel manganese cobalt oxide (NMC), graphite, A lithium salt dissolved in an organic or non-aqueous solvent and two additives are used to The electrolyte solvent may be any of the following solvents, alone or in combination: Can be used in combination: ethylene carbonate (EC), ethyl methyl carbonate Carbonate (EMC), Methyl acetate, Propylene carbonate, Dimethyl carbonate, Dimethyl carbonate Ethyl carbonate, another carbonate solvent (cyclic or acyclic), another organic solvent, and / or or another non-aqueous solvent. The solvent is present at a concentration higher than the additive, usually greater than 6% by weight. The catalyst was combined with two additive pairs disclosed (VC and FN, FEC and FN, VC and and FEC blends with FN, or other combinations), with properties desirable for various applications. The cathode is made of aluminum oxide (Al2O3), dioxide (Al2O3), and It may be coated with a material such as titanium (TiO2) or another coating material. Additionally, to save costs, the anode may be made from natural graphite, but the pricing structure limits this. For example, in certain instances, synthetic graphite is cheaper than natural graphite.

[0015] The disclosure herein demonstrates the symbiotic nature of the two-additive electrolyte system and selected electrodes. This is supported by experimental data. An exemplary battery system is shown in Figure 1, in which two additives (e.g., , FEC or VC, FN, graphite anode (either naturally occurring graphite or artificial synthetic graphite) , an NMC positive electrode, a lithium electrolyte (e.g., lithium hexafluorophosphate with chemical composition LiPF6) The solvent may be an organic solvent or a non-aqueous solvent.

[0016] An exemplary embodiment of the present application is a method of making a battery system with sealed cells, , assembling the positive and negative electrodes in a sealed cell; removing residual water from the sealed cell; Filling a sealed cell with a non-aqueous electrolyte in an active atmosphere, sealing the sealed cell in a vacuum, A formation process that involves charging and discharging a closed cell until it achieves an initial specified capacity. and performing a process in which the non-aqueous electrolyte contains lithium ions and a carbonate solvent. a first non-aqueous solvent comprising methyl acetate; a second non-aqueous solvent comprising vinylene carbonate; or fluoroethylene carbonate, and a first working additive of the following formula (I): TIFF0007730871000002.tif44111 and a second action-activated additive of 2-furanone.

[0017] In some embodiments, the electrolyte formulation may be used to reduce the gas in the battery system during the formation process. Helps prevent outbreaks.

[0018] In some embodiments, substantially all of the residual water is removed. Any residual water is removed.

[0019] In some embodiments, the initial capacity is a specified upper cutoff potential.

[0020] In another exemplary embodiment, the method does not include a post-conversion outgassing step.

[0021] In another exemplary embodiment, gas generation during the conversion process is achieved by using only the first working additive. The gas generation is suppressed by at least 50% compared to that during the formation process of a battery system containing the catalyst.

[0022] In another exemplary embodiment, the formation process drives the sealed cell at 11 mA (in this case C / 20 This includes charging to 4.2V and discharging to 3.8V at a constant current (C / x). If the cell has an initial capacity, C / x is the charge or discharge time of the cell at the selected current. indicates that it is x hours.

[0023] In another exemplary embodiment, removing residual water from the sealed cells allows the sealed cells to be heat sealed. The process involves opening the container in less than 100°C and drying under vacuum at 100°C for 12 hours.

[0024] In another exemplary embodiment, gas production is completely suppressed during the conversion process.

[0025] In another exemplary embodiment, the battery system includes only the first working additive. It has a capacity retention rate comparable to that of conventional systems.

[0026] In another exemplary embodiment, the concentration of the first actuation type additive is between 0.25% and 6% by weight. The range is.

[0027] In another exemplary embodiment, the concentration of the second actuation type additive is 0.1 wt % to 5 wt %. It is a range.

[0028] In another exemplary embodiment, the concentration of the first actuating additive is 2 wt. % and the second actuating additive is 2 wt. %. The concentration of the mold additive is 0.5% by weight to 1% by weight.

[0029] In another exemplary embodiment, the first working additive is fluoroethylene carbonate. do.

[0030] In another exemplary embodiment, the first working additive is vinylene carbonate.

[0031] In another exemplary embodiment, the non-aqueous solvent is a carbonate solvent.

[0032] In another exemplary embodiment, the non-aqueous solvent is ethylene carbonate, ethyl methyl carbonate, The carboxylic acid may be at least one selected from the group consisting of carboxylic acid carbonate and dimethyl carbonate.

[0033] In another exemplary embodiment, the solvent further comprises a second non-aqueous solvent.

[0034] In another exemplary embodiment, the second non-aqueous solvent is methyl acetate.

[0035] In another exemplary embodiment, the positive electrode comprises NMC532 with coarse micrometer-sized grains; Choose from standard NMC532 and NMC622.

[0036] In another exemplary embodiment, the negative electrode is selected from synthetic graphite and natural graphite. [Brief explanation of the drawings]

[0037] [Figure 1] FIG. 1 is a schematic diagram of a vehicle equipped with the system.

[0038] [Figure 2] FIG. 1 is a schematic diagram of an exemplary battery system.

[0039] [Figure 3] FIG. 1 is a schematic diagram of a lithium-ion battery cell system.

[0040] [Figure 4] 1 illustrates an exemplary configuration of an electrical circuit module and a contact module for cell formation, according to one embodiment of the present invention.

[0041] [Figure 5] Charging profiles and gas evolution for various electrolytes are shown.

[0042] FIG. 5A shows the charge profile of an electrolyte composition containing 2% FEC as the first electrolyte additive. and gas evolution.

[0043] FIG. 5B shows the results of the first electrolyte additive with 2% FEC and the second electrolyte additive with 0.5% FEC. 1 shows the charging profile and gassing of an electrolyte composition containing FN.

[0044] FIG. 5C shows the results of the electrolytic solution containing 2% FEC as the first electrolyte additive and 1% FN as the second electrolyte additive. 1 shows the charge profile and gassing of an electrolyte composition comprising:

[0045] [Figure 6A]1 shows the passivation effect of various electrolyte compositions in different types of cells. [Figure 6B] 1 shows the passivation effect of various electrolyte compositions in different types of cells.

[0046] Figure 6A shows the etch rate in a cell with a coated NMC532 cathode and a synthetic graphite anode. Ethylene carbonate (EC): ethyl methyl carbonate (EMC) (control) and 2% VC, 0.5%FN, 1%FN, 2%VC+1%FN, 2%FEC+1%FN and 1%L Explain the passivation effect of EC:EMC containing FO(LiPO2F2) + 1% FN do.

[0047] Figure 6B shows the ethylene carbonate (EC):ethyl methyl ester in a lithium-ion battery cell. Carbonate (EMC) (control), as well as 2% VC, 0.5% FN, 1% FN, and 2% VC Explains the passivation effect of EC:EMC including +1%FN and 2%FEC+1%FN do.

[0048] [Figure 7A] Electrochemical Impedance Spectroscopy (EIS) spectra and gas evolution for various electrolyte compositions in different types of cells. [Figure 7B] Electrochemical Impedance Spectroscopy (EIS) spectra and gas evolution for various electrolyte compositions in different types of cells.

[0049] Figure 7A shows the 2% VC, 2%FEC, 1%LFO, 0.5%FN, 1%FN, 2%VC+1%FN, 2%F EIS spectra of electrolyte compositions containing EC + 1% FN and 1% LFO + 1% FN and their This shows the gas evolution.

[0050] Figure 7B shows the results of the simulation of lithium-ion battery cells with 2% VC, 0.5% FN, 1% FN, and 2% VC+ EIS spectra of electrolyte compositions containing 1% FN and 2% FEC + 1% FN and Gas evolution is indicated.

[0051] [Figure 8A] Representative experimental data from a long-term cycling study at 40° C. is presented, C / 3CCCV, demonstrating the benefit of including FN as an additive to electrolyte systems containing VC or FEC. [Figure 8B] Representative experimental data from a long-term cycling study at 40° C. is presented, C / 3CCCV, demonstrating the benefit of including FN as an additive to electrolyte systems containing VC or FEC. [Figure 8C] Representative experimental data from a long-term cycling study at 40° C. is presented, C / 3CCCV, demonstrating the benefit of including FN as an additive to electrolyte systems containing VC or FEC. [Figure 8D] Representative experimental data from a long-term cycling study at 40° C. is presented, C / 3CCCV, demonstrating the benefit of including FN as an additive to electrolyte systems containing VC or FEC. [Figure 8E] Representative experimental data from a long-term cycling study at 40° C. is presented, C / 3CCCV, demonstrating the benefit of including FN as an additive to electrolyte systems containing VC or FEC.

[0052] Figure 8A shows the results for a cell with a coated NMC532 positive electrode and a synthetic graphite negative electrode. Discharge capacity of electrolyte systems containing 2% VC, 2% FEC, 0.5% FN, and 1% FN. Normalized capacitance and voltage hysteresis are shown.

[0053] FIG. 8B shows a 2% NMC532 positive electrode and a synthetic graphite negative electrode in a cell. Electrolyte systems containing VC, 2% FEC, 2% VC + 1% FN, and 2% FEC + 1% FN The discharge capacity, normalized capacity, and voltage hysteresis of the .

[0054] FIG. 8C shows the 1% Discharge capacity, normalized capacity and voltage of electrolyte systems containing LFO and 1% LFO + 1% FN Hysteresis is shown.

[0055] Figure 8D shows a lithium-ion battery cell containing 2% VC, 2% FEC, and 0.5% F as additives. Discharge capacity of electrolyte systems containing N and EC:EMC:DMC electrolyte with 1% FN, positive Normalized capacitance and voltage hysteresis are shown.

[0056] Figure 8E shows the results of the lithium-ion battery cell test using 2%VC+1%FN, 2%FEC+1%FN, and 2 Discharge capacity of electrolyte systems containing EC:EMC:DMC electrolyte with %VC and 2%FEC. The normalized capacitance and voltage hysteresis are shown. DETAILED DESCRIPTION OF THE INVENTION

[0057] The following description is presented to enable any person skilled in the art to make and use the embodiments, Various modifications to the disclosed embodiments are provided in connection with a particular application and its requirements. Those skilled in the art will readily appreciate that the general principles defined herein are within the spirit and scope of this disclosure. The present invention may be applied to other embodiments and applications without departing from the spirit and scope thereof. It is not intended to be limited to the embodiments shown, but to encompass the broadest scope consistent with the principles and features disclosed herein. A range should be given.

[0058] FIG. 1 shows the basic components of a battery-powered electric vehicle (EV) 100. The electric vehicle 100 includes at least one drive motor (traction motor) 402A and / or 402B, at least one motor coupled to the corresponding drive motor 402A and / or 402B; Two gearboxes 404A and / or 404B, a battery cell 406, and an electronic device 408 Generally, the battery cells 406 power and drive the electronics of the electric vehicle 100. Electric motors 402A and / or 402B are used to propel electric vehicle 100. The electric vehicle 100 may be any suitable vehicle not described herein but known to those skilled in the art. The electric vehicle 100 configuration of FIG. 1 has four wheels. Although shown as such, different electric vehicles may have fewer or more than four wheels. Additionally, motorcycles, airplanes, trucks, boats, trains, among other types of vehicles. Different types of electric vehicles 100, including engines, may be used in accordance with the inventive concepts described herein. Certain components made using embodiments of the present disclosure may be incorporated into the vehicle 100. It can be used in.

[0059] FIG. 2 is a schematic diagram of an exemplary energy storage system 200 showing various components. The energy storage system 200 typically includes at least a base 202 and four side walls. 204 (only two shown in the figure). The module housing is generally electrically insulated from the battery cells 206 contained therein. This is due to the physical separation, the electrical insulating layer, and the insulating material as the module housing. may occur through any combination thereof, or otherwise, depending on the selection of the fee. The base 202 may be an electrically insulating layer on a metal sheet, or a layer of polypropylene, polyurethane, or polyethylene. non-conductive / non-conductive materials such as polyvinyl chloride, other plastics, non-conductive composites or insulating carbon fiber The sidewall 204 may also be provided with an insulating layer or may be made of an electrically insulating material. Polyethylene, polyurethane, polyvinyl chloride, other plastics, non-conductive composites or It may be made from a non-conductive or electrically insulating material such as insulating carbon fiber. The interconnect layer 230 can be disposed over the battery cells 206, and the top plate 210 can be disposed over the The top plate 210 may be a single plate or may be disposed on top of the interconnect layer 230. The individual battery cells 106 and 206 may be formed from multiple plates. A lithium-ion battery cell includes an electrolyte containing lithium ions and has a positive electrode and a negative electrode. This is often the case.

[0060] FIG. 3 shows a schematic diagram of a lithium-ion cell 300. Lithium ions 350 are contained in a container 3 The electrolyte 320 is dispersed throughout the container 360. The container 360 may be part of a battery cell. Lithium ions 350 move between the positive electrode 330 and the negative electrode 340. 370 separates the negative and positive terminals. Circuit 310 connects the negative and positive terminals.

[0061] FIG. 4 illustrates an electrical circuit module and contacts for cell formation according to one embodiment of the present invention. 1 shows an example configuration of a contact module 102. The electrical circuit modules 104 are arranged adjacent to each other. The cell being performed is connected to a contact in one of the receptacles of the contact module 102. The circuit modules 104 each have a cell. Several electrical circuits corresponding to receptacles on the contact module 102 for receiving Each cell's unique circuitry is appropriate for the cell housed in the receptacle. The cell can be configured to provide a controlled voltage to the cell and collect measurements of the cell. The contact module 102 and the circuit module 103 together form an interface block. This compact configuration of the roller 104 eliminates the need for large amounts of cable, as is the case with conventional forming systems. Note that this eliminates the need for large amounts of cabling, which can be expensive and space-consuming. This can take a long time to install / repair and can cause inefficiencies and reduced accuracy. This could lead to:

[0062] The contact module 102 has a plurality of pogo pins in a receptacle. The contact module 102 may be equipped with a "pogo board" Note that this is sometimes referred to as a "hardware." In one embodiment, two modules The contact modules are arranged so that the modules form a single rigid entity. The cable 102 and circuit module 104 can be mounted together with spacers 103 . In addition, the contact module 102 has 32 contacts to accommodate 32 cells at once. Receptacles may be provided. Other numbers of receptacles are possible.

[0063] Contact module / circuit module combinations for scalable and easy automated operation The combination is attached to the upper platform 108, and the cell in which the anodization is taking place is attached to the lower platform. The upper platform 108 and the lower platform 110 can be held by the Both the platform 110 and the frame 106 may be housed in the frame 106. In one embodiment, The upper platform 108 and the lower platform 110 are arranged in a "clamshell" fashion. Specifically, actuator 122 can be actuated to move vertically. can move the bottom platform 110 upward, and the actuator 124 The upper platform can be moved downwards. Thus, the frame 106 The cell is placed on a bottom platform 110, which is sometimes referred to as a "clamshell structure." After this, the top platform 108 and the bottom platform 110 are moved towards each other. The top of the cell can be actuated to move relative to the cell contact module. Each receptacle in the contact module (similar to the contact module 102) is located inside the The vertical position of the bottom platform 110 can be fixed. and then move only the upper platform 108 downward to contact the cell, or The reverse is also possible. It should be noted that the configuration has certain advantages. By using only the clamping fixture, the complexity of the clamping fixture is eliminated and the clamping fixture The overall space can be reduced by approximately one-third. In addition, the cell connection is only at the top. This configuration also eliminates the need for cables to the bottom of the cell, providing the benefits mentioned above. The modules and circuit modules are separate power electronics modules and long cables. It also helps eliminate the need for cable wiring.

[0064] In the embodiment shown in FIG. 4, the clamshell structure 106 includes eight cell interface blocks. Each of the contact modules and the circuit module can accommodate a plurality of blocks. Each block can accommodate 32 cells. The entire structure can process 32 x 8 = 256 cells simultaneously. Other numbers of cells per block and Such a tight packing of cells increases the efficiency of operation per cell (operation Operational expenditure (OPEX) and total CAP This can cause a drop in EX, as the contact board and the power and control module This cannot be achieved with conventional chemical conversion systems, which are separated into two, and connecting the two is complicated. Space-consuming cabling is required.

[0065] To further improve cell packing density, some clamshell structures such as structure 106 , can be housed in a larger rack, such as rack 112. In this embodiment, the rack The 112 can accommodate seven clamshell structures, bringing the total number of cells in formation to 1792 Other numbers of clamshell structures are possible. System Control and AC Bulky electrical components such as the DC / DC power conversion module 114 are housed in a clamshell structure. Note that a plurality of clamshell structures are provided for each clamshell structure and placed near each clamshell structure. In this form, AC / DC power conversion modules can be provided in a centralized manner for each rack. can.

[0066] New research by the inventors has revealed novel methods for use in grid and electric vehicle applications. Suitable electrolytes and battery systems were identified. These systems consisted of vinylene carbonate ( VC) and 2-furanone (FN), and fluoroethylene carbonate (F Two-additive electrolyte systems in combination with solvents and electrodes, including a combination of EC and FN These two-additive electrolyte systems are based on LNi x Mn y Co z O2 composition and paired with a positive electrode made from lithium nickel manganese cobalt oxide (generally is abbreviated as NMC or NMCxyz, where x, y, and z are nickel, manganese, and zinc, respectively. (x+y+z=1) In certain embodiments, The poles are made of NMC111, NMC532, NMC811 or NMC622. In certain embodiments, the crystal has micrometer-sized areas of continuous crystal lattice (or coarse grains). The electrodes were formed from single-crystal micrometer-sized particles of NMC532. The cathode has been shown to be particularly robust, in part due to the materials and processing conditions. This results in larger particle sizes than would be possible using conventional materials and processing conditions.

[0067] Typical processing conditions result in nanometer-sized particles being converted into larger micrometer-sized particles. This results in an NMC electrode packed into small aggregates, creating grain boundaries at the nanometer scale. Grain boundaries are prone to defects that tend to degrade desirable properties (e.g., electrical properties). Therefore, it is generally desirable to reduce the number of coarse grains and increase the grain size. NMC electrodes can be used to create larger domains on the meter-size scale. This reduces the number of grain boundaries and improves electrical properties. Improved properties lead to a more robust battery system. In certain embodiments, other NMC electrodes are treated to form larger domains. Size (micrometer size scale or larger), e.g., NMC111, NMC811 , NMC622, or another NMC compound to create a more robust system. can.

[0068] The positive electrode can be aluminum oxide (Al2O3), titanium dioxide (TiO2), or another coating. The positive electrode may be coated with a material such as a coating material. To reduce interfacial phenomena at the positive electrode, such as charging, or other phenomena that may degrade the system. The negative electrode can be made of natural graphite, artificial graphite, graphite / SiO blend, or It may be made from metal or other materials.

[0069] The electrolyte is ethylene carbonate (EC), ethyl methyl carbonate (EMC), and acetic acid. Methyl acetate (MA), propylene carbonate, dimethyl carbonate (DMC), diethyl carbonate, another carbonate solvent (cyclic or acyclic), another organic solvent, and / or Lithium salts (Li) dissolved in a combination of organic or non-aqueous solvents with another non-aqueous solvent The solvent may be present in a concentration higher than that of the additive, typically about 5% by weight or more. are present in concentrations above about 6 wt%. Experimental data for NMC / graphite cells show that EC and EMC was generated using electrolyte solvents containing (with or without DMC and / or MA) These solvents are merely examples of other carbonate solvents, particularly other non-aqueous solvents. To understand the effect of solvents, electrodes, and solvents, EC and EMC were used in the experiments. Therefore, the electrolyte system was composed of propylene carbonate, ethylene carbonate, and Carbonate, Dimethyl Carbonate, Ethyl Methyl Carbonate, Diethyl Carbonate , other carbonate solvents (cyclic or acyclic), other organic solvents, and / or other non-aqueous solvents. Other carbonate solvents and / or other non-carbonate solvents can be used, including The solvent is present in a higher concentration than the additive, typically greater than 5% or 6% by weight.

[0070] In the two-additive mixture of FEC and FN, the concentration of FEC is preferably 0.5% by weight to 6% by weight. The concentration of VC and FN is preferably 0.25% to 5% by weight. In the two-additive mixture of N, the concentration of VC is preferentially 0.5 wt% to 6 wt%, and that of FN The concentrations are preferentially 0.1% to 5% by weight, 0.15% to 5% by weight, 0.2% to 5% by weight % by weight, and 0.25% to 5% by weight.

[0071] These particular new battery systems are expected to be used in energy storage applications as well as in automotive applications (electric vehicles). In this application, the rate of charge and discharge, as well as The life span when rapidly charging and discharging is important.

[0072] Preliminary experiment configuration Although the battery system itself may be packaged separately according to the present disclosure, the experimental setup is Typically, a machined "sealed cell" is used to contain a two-additive electrolyte system and positive and negative electrodes. Systematically evaluate battery systems using common configurations, including specific materials for electrode use. All percentages referred to within this disclosure are percentages by weight unless otherwise specified. Those skilled in the art will appreciate that the types of additives used and the concentrations employed will determine the most desirable and improved results. Improved properties, as well as other components and components used in the resulting lithium-ion battery It is understood that the present invention will be apparent from the disclosure and will not be limited to the specific embodiments described herein.

[0073] Closed Cell The NMC / graphite sealed cell used in the experimental setup contained 1M LiPF in a solvent with additives. The electrolyte was 1M of 1.2M LiPF in 30% EC and 70% EMC. The electrolyte components were modified to include MA and / or DMC. To this electrolyte, additive components were added at specific weight percentages.

[0074] The sealed lithium-ion battery cells used in the experimental configuration were EC with a volume ratio of 25:5:70; The electrolyte solvent consisted of 1.2M LiPF6 added to EMC and DMC. To the solution, additive components were added at specific weight percentages.

[0075] Closed NMC / graphite cells are filled with coarse micrometer-sized N particles unless otherwise specified. Cathode made of MC532 (sometimes called single crystal NMC532) and synthetic graphite To test the specific battery system, a standard NMC532 (Magnetoresistive) (micrometer-sized coarse particles smaller than NMC) and other positive Anodes and cathodes (containing natural graphite) were used.

[0076] Before filling the electrolyte, the sealed cells were cut open below the heat seal and heated at 100°C for 12 hours. Residual moisture was removed by vacuum drying, and the cells were then immediately transported for filling and vacuum sealing. After transferring to an argon-filled glove box, the cell was filled with electrolyte. It was sealed empty.

[0077] After sealing, the sealed cell was placed in a temperature box at 40.0 + / - 0.1°C and tested at 1.5V for 24 hours. The sealed cell was then subjected to a chemical conversion process. Unless otherwise noted, the formation process for NMC / graphite cells is performed at 11mA (C / 20) up to 4.2V. The sealed cell was charged at 1000 kJ / s and discharged to 3.8 V. C / x is the initial capacity of the cell. If there is a current, it means that the time it takes to charge or discharge the cell at the selected current is x hours. For example, C / 20 indicates that it takes 20 hours to charge or discharge. The tube was then moved to a glove box, cut open to release the gas, and vacuum sealed again. The experiment was stopped and appropriate experiments were performed.

[0078] The formation process of lithium-ion battery cells for cycling and storage experiments is a sealed cell. Charging the cell at C / 2 for 1 hour at 40°C, storing the cell at 60°C for 22 hours, The test consisted of charging the battery to 4.2V at C / 2 at 40°C and discharging it to 3.8V. After the anodization, the cell was moved to a glove box and cut open to release the generated gas. The container was then vacuum sealed again and the appropriate experiments were carried out.

[0079] Lithium-ion battery cells for charging experiments, profile experiments, and gas volume measurement experiments The formation process consisted of charging the sealed cell at 40°C for 1 hour at C / 20, then charging the cell at 60°C for 1 hour. Storing for 22 hours, charging the cell at C / 20 to 4.2V at 40°C, and 3. After the formation, the cell was transferred to a glove box and then turned off. It was opened to release any evolved gases, then resealed in vacuum and the appropriate experiment performed. Charging profile and gas amount measurement

[0080] The formation process is used to prepare cells for grid storage or energy storage in vehicles such as electric vehicles. This is done before the cells are used in their intended applications, such as storage. During formation, the cells are precisely controlled These electrodes and electrodes are subjected to a series of charge-discharge cycles to prepare them for their intended use. The purpose is to activate the electrolyte and the catalyst. Gas is generated during the formation process. A sufficient amount of gas is generated (depending on the specific tolerances and cell packaging that can be tolerated) In this case, it may be necessary to release the gas after the conversion process and before use in the application. These usually require the additional step of breaking the seal and then resealing it. As is common with many battery systems, choose a system that produces less gas if possible. It would be desirable to eliminate these steps by

[0081] The gas content experiments were carried out as follows: Ex-situ (static) gas measurements were used to measure the formation Gas production during cycling was measured using Archimedes' principle. The cell was suspended from a balance while submerged in the liquid. The change in volume before and after the experiment is directly related to the change in volume due to the change in buoyancy. The change in cell mass Δm is related to the change in cell volume Δv by Δv = -Δm / ρ. The gases generated during the voltage application and high potential holding period were analyzed by Aiken et al. (CPA iken, J.Xia, David Yaohui Wang, D.A. Stevens ,S.Trussler and JRDahn,J.Electrochem.S. oc.2014volume161,A1548-A1554) The measurements were carried out using an in-situ gas measurement device.

[0082] In certain embodiments, a two-additive electrolyte system is used in which the concentration of each additive is between about 0.25% and 6%. The system forms part of the battery system. 1 shows the charging profile and gassing of various electrolytes when tested.

[0083] As shown in Figures 5A to 5C, the charging profile of the battery cell was Furthermore, as shown in Figure 5C, the EC:EMC:DMC The charge profile for the electrolyte composition containing 80% EC:EMC:DMC+20%MA The charging profile is similar to that of an electrolyte composition containing This indicates that it is unrelated to the body.

[0084] 5A-5C also show gas evolution in various electrolyte systems. They found that, surprisingly, the presence of FN in the electrolyte composition significantly reduced the amount of FE added to the electrolyte with only 2% FE as an additive. It was found that gas generation during cell formation was significantly suppressed compared to electrolyte compositions containing C. As shown in Figures 5B and 5C, when at least 0.5% FN is present, FN The suppression of gas production observed after the addition of FN is independent of the amount of FN. an electrolyte composition containing 2% FEC + 0.5% FN as an additive (FIG. 5B); It was produced in a cell containing 2% FEC + 1% FN as an additive (Figure 5C). As shown, the suppression of gas production is independent of the main component of the electrolyte composition. The amount of gas production was not affected by the addition of 20% MA to the electrolyte composition. This prediction of FN-containing electrolyte compositions leads to a significant reduction in gas generation during the formation process. As a result of the excellent effect, the manufacturing process of the battery system is Eliminating this can be more efficient and cost effective. This outgassing process generally requires opening and resealing the battery system, which can lead to manufacturing Build time increases and efficiency decreases due to potential solvent evaporation. Passivation Effect

[0085] The passivation effect of various electrolyte compositions in different types of cells is shown in Figures 6A-6C. 6B, where the differential capacity (dQ / dV) plots against the cell voltage during formation charging. As can be seen from the data in Figures 6A-6B, FN is passive at 2.4V. The figure shows the excitation peaks from VC and EC at 2.85 V and 3 V, respectively. Figure 6A shows a battery with a coated NMC532 positive electrode and an artificial graphite negative electrode. Ethylene carbonate (EC): ethyl methyl carbonate (EMC) (control) in the same cell ), and 2%VC, 0.5%FN, 1%FN, 2%VC+1%FN, 2%FEC+1% Explain the passivation effect of FN and EC:EMC containing 1% LFO and 1% FN Figure 6B shows the behavior of ethylene carbonate (EC):ethyl methyl ester in a lithium-ion battery cell. Carbonate (EMC) (control), as well as 2% VC, 0.5% FN, 1% FN, and 2% VC Explains the passivation effect of EC:EMC including +1%FN and 2%FEC+1%FN do.

[0086] Cell Impedance The dual additive electrolyte system and novel battery system disclosed herein provide low cell yields. The cell impedance reduces the energy efficiency of the cell. It is desirable to minimize cell impedance. Conversely, low impedance Higher charging rates and greater energy efficiency.

[0087] Cell impedance was measured using electrochemical impedance spectroscopy (EIS). Sealed cells use monocrystalline NMC532 positive electrodes and artificial negative electrodes unless otherwise noted. EIS measurements were performed after the formation. Before moving to a temperature box at 10.0 + / - 0.1°C, The cell was charged or discharged to 3.80 V. The AC impedance spectrum was measured at 10.0 + / - 10.0 V. 10 points per 10 minutes from 100kHz to 10mHz with a signal amplitude of 10mV at -0.1°C In certain embodiments, the concentration of each additive was about 0.25% to 6%. An additive electrolyte system forms part of the battery system.

[0088] The effect of FN on impedance is illustrated in Figures 7A-7B, which shows Generally, the impedance is higher than that in cells that do not contain FN in the electrolyte composition. However, the gas generation during the anodization process was significantly low (Fig. 7A) or negligible (Fig. 7B). The associated benefits are that any impedance observed in cells containing FN as an additive in the electrolyte composition is eliminated. -This also exceeds the increase in dance.

[0089] Ultra-high precision cycling and storage experiments To study the effectiveness of the disclosed battery system including the working electrolyte additive and electrodes, Ultrahigh precision cycling (UHPC) The standard UHPC procedure was performed at 40°C using a current corresponding to C / 3. The data consisted of cycling the cell at 4.3 V. In this case, coulombic efficiency, charge end point capacity deviation, and other parameters are The UHPC procedure is fully detailed in this paper. Incorporated herein: TM Bond, JCBurns, DA Steven s,HMDahn,and JRDahn,Journal of the E Electrochemical Society, 160, A521 (2013) It has been done.

[0090] Metrics measured and / or determined from UHPC measurements of particular interest include Coulomb efficiency rate, normalized coulombic efficiency, normalized charge endpoint capacity deviation, normalized discharge capacity (or fade rate), and delta-V. Coulombic efficiency is the discharge capacity of the previous cycle. (Q d ) to the charging capacity (Q c ) Coulombic efficiency is the efficiency that occurs in a Li-ion cell. It tracks the parasitic reactions occurring in the cell and includes contributions from both the positive and negative electrodes. This indicates that the deterioration of the electrolyte is small. The coulomb efficiency per hour (CIE / h) is (1 is the normalized coulombic efficiency (per unit time), where the coulombic efficiency is defined as 1-CE. CIE / h is calculated by taking 1-CE and dividing by the cycle time for which CE is measured. The movement (or deviation) of the charging endpoint capacity is due to the parasitic reactions occurring at the positive electrode and If the cathode material is in a low-temperature state, the mass loss of the cathode material is tracked. The less movement the better, and the less oxidation of the electrolyte occurs. Normalized discharge capacity, or fade rate, is another important metric. A lower fade rate is desirable and typically indicates a longer battery system life. ΔV is calculated as the difference between the average charge voltage and the average discharge voltage. The change in ΔV is the growth of polarization. is closely related to the ΔV, and the change in ΔV becomes smaller as cycling occurs. PC measurements can accurately track metrics with greater precision and differentiate between different degradation mechanisms. The rapidity of the evaluation makes it particularly suitable for comparing electrolyte compositions.

[0091] In certain embodiments, a two-additive electrolyte system is used in which the concentration of each additive is between about 0.25% and 6%. The battery system also includes NMC111, NMC5 32, NMC811, NMC622, or other NMC compositions (NMCxyz) In certain embodiments, the positive electrode may comprise a micrometer-scale coarse-grained NMC. The cathodes made from 532 are, in part, due to the processing conditions producing a higher ionic strength than typical processing conditions would produce. It has been shown to be particularly robust for producing large grain sizes.

[0092] Typical processing conditions result in nanometer-sized particles being converted into larger micrometer-sized particles. This results in an NMC electrode packed into small aggregates, creating grain boundaries at the nanometer scale. Grain boundaries are prone to defects that tend to degrade desirable properties (e.g., electrical properties). Therefore, it is generally desirable to reduce the number of coarse grains and increase the grain size. NMC allows for the creation of larger domains on the micrometer-sized scale. The number of grain boundaries in the electrodes is reduced, improving electrical properties. These improved properties lead to a more robust battery system. In certain embodiments, other NMC electrodes can be processed to provide larger domains. In-size (micrometer size scale or larger), e.g., NMC111, NMC8 11, NMC622, or another NMC compound to create a more robust system. This can be done.

[0093] In a particular embodiment, a lithium-ion battery cell containing a graphite-SiO electrode was used.

[0094] Long-term cycling The lifespan of a battery system is an important characteristic of the battery system. The rate of charging and discharging affects the lifespan. Long-term cycling experiments can be used to assess resilience under expected operating conditions. It helps determine the aging of a battery system. The choice of system is important.

[0095] Embodiments of the present disclosure provide desirable long-term storage for a variety of applications, including grid and vehicle storage. Shows cycling.

[0096] Specifically, the two-additive electrolyte systems of VC+FN and FEC+FN have EC as the solvent. They are used in automotive applications (especially electric vehicles) where charge and discharge rates are typically higher than in grid storage applications. Related to energy storage in automobiles.

[0097] For long-term cycling experiments, single crystal NMC532 was typically used as the cathode (unless otherwise specified). In another embodiment, graphite was used as the negative electrode, and artificial graphite was used as the negative electrode (unless otherwise specified). used lithium-ion battery cells. Before the long-term cycling experiment, as described above, The sealed cell was subjected to a formation process. Generally, the cell was placed in a glove box after the formation process. It is moved and cut open to release gases produced during the conversion process. However, since gas generation during the cell formation is negligible, For cells containing FN as an additive, this additional step was not necessary. The cells were cycled in a Neware charging system. The cells were charged at 40°C + / - 0.2°C or 20°C. The temperature was controlled in a temperature controlled box at + / - 0.2°C. The temperature was 3.0V and C / 3 (3-hour half cycle). ) current at the start of charging (top of charge) (4.2V or 4.3V) During the constant voltage step at the beginning of charge, the cell was cycled until the current fell below C / 20. For every 0 cycle, the cell underwent one complete cycle at C / 20.

[0098] In certain embodiments, a two-additive electrolyte system is used in which the concentration of each additive is between about 0.25% and 6%. The system forms part of the battery system. Figures 8A-8E show typical experimental data from a long-term cycling study at 40°C. C / 3CCCV uses FN as an additive to electrolyte systems containing VC or FEC. Demonstrate the benefits of inclusion. Long-term cycling using coated NMC532 as the positive electrode and artificial graphite as the negative electrode The results of the test are shown in Figures 8A to 8C. The results of the icing are shown in Figures 8D to 8E. As shown in these figures, the electrolyte composition The addition of FN to the composition does not significantly affect the long-term cycling properties of the battery system. Combined with a significant reduction in gas generation during the formation process, batteries containing FN as an additive The system may have unexpectedly superior performance compared to standard battery systems. (See Figure 8C).

[0099] The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. Therefore, whether expressly stated or implied herein, Nevertheless, various alternative embodiments and / or modifications to the present disclosure may be made in light of the present disclosure. Although the embodiments of the present disclosure have been described in this manner, those skilled in the art will be able to It will be understood that changes can be made in form and detail without departing from the scope of the present disclosure. Accordingly, the present disclosure is limited only by the claims. References to additives in the specification generally refer to active agents unless otherwise specified herein. Refers to additives.

[0100] In the foregoing specification, the present disclosure has been described with reference to specific embodiments. As will be appreciated by those skilled in the art, the various embodiments disclosed herein are intended to be illustrative and not restrictive, and are not intended to be limiting unless otherwise specified. It may be modified or implemented in various other ways without departing from the spirit and scope of the present invention. The description should be considered exemplary and should not be construed as limiting the scope of the invention. The present disclosure is intended to teach those skilled in the art how to make and use the embodiments. It is understood that the forms of the disclosure shown and described are to be taken as exemplary embodiments. It is to be understood that equivalent elements or materials may be used in place of those typically illustrated and described herein. Furthermore, certain features of the present disclosure may be used independently of the use of other features. any of which will be apparent to those skilled in the art after having the benefit of this description of the present disclosure. The term "including" is used to describe and claim this disclosure. ), "comprising", "incorporating" "ing", "consisting of", "have", etc. The expressions should be construed in a non-exclusive manner, i.e., not expressly stated. There may be more items, components or elements. Reference to the singular also relates to the plural. References to "about" or "approximately" should be construed as plus or minus 10%. %. Similarly, any reference to any percentage of an additive is interpreted to mean plus or minus 10%.

[0101] Furthermore, the various embodiments disclosed herein are intended to be illustrative and explanatory. and should not be construed as limiting the disclosure in any way. References (e.g., attached, pasted, joined, connected, etc.) are intended to aid the reader in understanding this disclosure. and is intended to be used only in connection with the position, orientation, or use of the systems and / or methods specifically disclosed herein. Therefore, binding references, if any, are to be interpreted broadly. Furthermore, such join references do not necessarily mean that the two elements are directly connected to one another. It is not something to speculate about.

[0102] Additionally, without limitation, terms such as "first," "second," "third," "primary," and "secondary" are used. All absolute numbers, such as "secondary," "primary," or other conventional terms and / or numerical values, are used throughout this disclosure. Identifiers to assist the reader in understanding the various elements, embodiments, variations and / or modifications and shall be taken solely as a general rule and shall not be construed as limiting the scope of any particular element, embodiment, variation and / or modification. No limitations can be placed on the order or priority of the elements, embodiments, variations and / or modifications. stomach.

[0103] Also, one or more elements shown in the drawings / diagrams may be useful depending on the particular application. may also be implemented in a more separate or integrated manner, or even in certain cases It is understood that the content may be deleted or disabled. [Prior art documents] [Patent documents]

[0104] [Patent Document 1] U.S. Patent Application Publication No. 2017 / 0025706 [Non-patent literature]

[0105] [Non-Patent Document 1] J.C. Burns et al., Journal of the Electrochemical Society, 160, A1451 (2013)

Claims

1. 1. An energy storage device, comprising: A positive electrode and a negative electrode; A non-aqueous electrolyte solution, A lithium salt, a first non-aqueous solvent comprising a carbonate solvent; a second non-aqueous solvent comprising methyl acetate; an additive mixture comprising a first working type additive and a second working type additive; the first working additive comprises either vinylene carbonate, fluoroethylene carbonate, or any combination thereof; The second working additive is represented by the following formula (I): and 2-furanones having the formula: the concentration of the first non-aqueous solvent and the second non-aqueous solvent is greater than 6% by weight; The concentration of the first working additive is in the range of 0.25% to 6% by weight; A non-aqueous electrolyte solution in which the concentration of the second working additive is in the range of 0.1 wt % to 5 wt %; 1. An energy storage device comprising:

2. 10. The energy storage device of claim 1, wherein the energy storage device has a capacity retention rate comparable to an energy storage device containing only the first working type additive.

3. 10. The energy storage device of claim 1, wherein the non-aqueous electrolyte is configured to suppress gas generation compared to gas generation during a formation process of an energy storage device including only the first working-type additive.

4. 2. The energy storage device of claim 1, wherein the concentration of the first working type additive is 2% by weight, and the concentration of the second working type additive is 0.5% to 1% by weight.

5. 5. The energy storage device of claim 1, wherein the first actuating additive comprises fluoroethylene carbonate.

6. 5. The energy storage device of claim 1, wherein the first actuating additive comprises vinylene carbonate.

7. 5. The energy storage device of claim 1, wherein the first non-aqueous solvent is a carbonate solvent.

8. 8. The energy storage device of claim 7, wherein the first non-aqueous solvent is at least one selected from ethylene carbonate, ethyl methyl carbonate, propylene carbonate, dimethyl carbonate, and diethyl carbonate.

9. 5. The energy storage device of claim 1, wherein the lithium salt comprises lithium hexafluorophosphate.

10. 5. The energy storage device of claim 1, wherein the second non-aqueous solvent is methyl acetate.

11. 5. The energy storage device of claim 1, wherein the positive electrode comprises lithium nickel manganese cobalt oxide (NMC).

12. 12. The energy storage device of claim 11, wherein the NMC is selected from the group consisting of NMC111, NMC532, NMC811, and NMC622.

13. 5. The energy storage device of claim 1, wherein the negative electrode comprises an anode active material selected from the group consisting of artificial graphite, natural graphite, and graphite / SiO blends.

14. 5. The energy storage device of claim 1, wherein the non-aqueous electrolyte is configured to produce at least 50% less gas during a formation process compared to gas produced during a formation process of an energy storage device including only the first working-type additive.

15. The energy storage device of claim 1 , wherein the energy storage device is a battery.

16. An electric vehicle equipped with a rechargeable battery, A drive motor; The gearbox and Electronic devices and The energy storage device according to any one of claims 1 to 4.

17. 17. The electric vehicle of claim 16, wherein the first working additive comprises fluoroethylene carbonate.

18. 18. The electric vehicle of claim 17, wherein the first working additive further comprises vinylene carbonate.

19. 1. An energy storage device, comprising: A positive electrode and a negative electrode; A non-aqueous electrolyte solution, A lithium salt, a first non-aqueous solvent comprising a carbonate solvent; a second non-aqueous solvent comprising methyl acetate; an additive mixture comprising a first working type additive and a second working type additive; the first working additive comprises vinylene carbonate; The second working additive is represented by the following formula (I): and 2-furanones having the formula: the concentration of the first non-aqueous solvent and the second non-aqueous solvent is greater than 6% by weight; The concentration of the first working additive is in the range of 0.25% to 6% by weight; A non-aqueous electrolyte solution in which the concentration of the second working additive is in the range of 0.1 wt % to 5 wt %; 1. An energy storage device comprising:

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