Battery cell with solid electrolyte interface layer and method

Abstract

A vehicle battery cell, a vehicle, and a method of forming the battery cell are provided herein. The vehicle battery cell includes an anode current collector, an anode disposed on the anode current collector, a solid electrolyte interface layer disposed on the anode, a separator disposed on the solid electrolyte interface layer, a cathode disposed on the separator, and a cathode current collector disposed on the cathode. The separator includes lithium nitride (Li3N), and the lithium nitride (Li3N) induces uniform deposition of lithium on the anode.

Description

Technical Field

[0001] This disclosure relates to a battery cell, and more specifically, to a battery cell having a solid electrolyte interface layer. Background Technology

[0002] Electric and hybrid electric vehicle technologies benefit from the development and deployment of rechargeable secondary batteries that power vehicle drivetrains. Secondary batteries include lithium-ion batteries, which typically consist of a cathode, anode, separator, and electrolyte. The cathode provides the source of lithium ions and determines the battery's capacity and average voltage. The anode stores and releases the lithium ions received from the cathode when energy is needed. The separator prevents the cathode and anode from contacting each other, avoiding short circuits, while the electrolyte provides the medium between the cathode and anode through which lithium ions move. Charging time is a critical factor in electric vehicles. High-speed charging battery cells have the potential to significantly reduce charging time.

[0003] Therefore, while current battery chemistry systems have achieved their intended purpose, new and improved battery chemistry systems are still needed to provide greater stability and better cycle performance. Summary of the Invention

[0004] According to several aspects of this disclosure, a vehicle battery cell is provided. The vehicle battery cell includes an anode current collector, an anode disposed on the anode current collector, a solid electrolyte interface layer disposed on the anode, a separator disposed on the solid electrolyte interface layer, a cathode disposed on the separator, and a cathode current collector disposed on the cathode. The separator comprises lithium nitride (Li3N), and the lithium nitride (Li3N) induces lithium to be uniformly deposited on the anode.

[0005] According to another aspect of this disclosure, the anode includes graphite, silicon carbide (SiC), or silicon oxide (SiO2). x At least one of the following.

[0006] According to another aspect of this disclosure, the cathode includes at least one of lithium cobalt oxide (LCO), lithium nickel manganese cobalt oxide (NMC), lithium nickel cobalt aluminum oxide (NCA), lithium iron phosphate (LFP), or lithium manganese oxide (LMO).

[0007] According to another aspect of this disclosure, the cathode comprises lithium iron phosphate (LFP) and the anode comprises graphite.

[0008] According to another aspect of this disclosure, the cathode comprises lithium iron phosphate (LFP), and the anode comprises a graphite and silicon-carbon composite anode.

[0009] According to several aspects of this disclosure, a vehicle is provided. The vehicle includes a plurality of battery cells assembled together. Each battery cell includes an anode current collector, an anode disposed on the anode current collector, a solid electrolyte interface layer disposed on the anode, a separator disposed on the solid electrolyte interface layer, a cathode disposed on the separator, and a cathode current collector disposed on the cathode. The separator includes lithium nitride (Li3N), and the lithium nitride (Li3N) induces lithium to be uniformly deposited on the anode.

[0010] According to another aspect of this disclosure, the anode includes graphite, silicon carbide (SiC), or silicon oxide (SiO2). x At least one of the following.

[0011] According to another aspect of this disclosure, the cathode comprises lithium iron phosphate (LFP) and the anode comprises graphite.

[0012] According to another aspect of this disclosure, the cathode comprises lithium iron phosphate (LFP), and the anode comprises a graphite and silicon-carbon composite anode.

[0013] According to another aspect of this disclosure, the battery is a pouch battery.

[0014] According to several aspects of this disclosure, a method for forming a battery cell is provided. The method includes: applying a cathode to a cathode current collector, applying an anode to an anode current collector, positioning a separator between the cathode and the anode, assembling the cathode, anode, and separator into a battery cell housing, adding an electrolyte to the battery cell housing, sealing the battery cell housing, and charging and discharging the battery cell during formation, thereby forming a uniformly deposited solid electrolyte interface (SEI) layer on the anode surface. The electrolyte is in contact with the cathode, anode, and separator, and the electrolyte includes at least one lithium-based additive, nitrate, or nitrite. At least one of the lithium-based additive, nitrate, or nitrite promotes the formation of the solid electrolyte interface (SEI) layer, and the solid electrolyte interface (SEI) layer includes lithium nitride (Li3N).

[0015] According to another aspect of this disclosure, the nitrate is lithium nitrate (LiNO3).

[0016] According to another aspect of this disclosure, the concentration of lithium nitrate (LiNO3) is between 0.2 and 2.0 wt.%.

[0017] According to another aspect of this disclosure, nitrates include potassium nitrate (KNO3), sodium nitrate (NaNO3), and tetramethylammonium nitrate ((CH3)4N). + NO3 - Tetraethylammonium nitrate ((C2H5)4N) + NO3 -), tetrapropylammonium nitrate ((C3H7)4N + NO3 - At least one of the following: ( ) or isosorbide dinitrate (C6H8N2O8).

[0018] According to another aspect of this disclosure, nitrites include at least one of lithium nitrite (LiNO2), sodium nitrite (NaNO2), or potassium nitrite (KNO2).

[0019] According to another aspect of this disclosure, the electrolyte is a suspended electrolyte comprising lithium (Li3N) nanoparticles.

[0020] According to another aspect of this disclosure, the size of the nanoparticles is between 10 and 500 nanometers (nm).

[0021] According to another aspect of this disclosure, the electrolyte comprises lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonyl)imide (LiFSI), wherein the concentration of lithium nitrate is 0.5 wt.%.

[0022] According to another aspect of this disclosure, the liquid electrolyte comprises lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonyl)imide (LiFSI), wherein the concentration of lithium nitrate is 0.6% by weight.

[0023] According to another aspect of this disclosure, charging and discharging include 100% Extreme Fast Charging (XFC).

[0024] The above-described features and advantages, as well as other features and advantages, of the systems and methods disclosed herein will become apparent from the detailed description, including the claims and embodiments, and in conjunction with the accompanying drawings. Attached Figure Description

[0025] This disclosure will be more fully understood through the following detailed description and accompanying drawings, in which:

[0026] Figure 1 The perspective view shows an example of a vehicle according to the present disclosure, which has an electric motor powered by a battery pack having a solid electrolyte interface layer that promotes uniform deposition of lithium (Li).

[0027] Figure 2 Based on this disclosure Figure 1 A schematic diagram of the cross-section of the battery cells within the battery pack of the vehicle shown.

[0028] Figure 3 A cross-sectional schematic diagram illustrating the present disclosure Figure 1 The battery cells in the battery pack of the vehicle shown include a solid electrolyte interface layer that promotes uniform deposition of lithium (Li).

[0029] Figure 4 The flowchart illustrates the formation according to this disclosure. Figure 3 The method for the battery cell shown includes a solid electrolyte interface layer that promotes uniform deposition of lithium (Li). Detailed Implementation

[0030] The following description is exemplary in nature only and is not intended to limit this disclosure, its application, or its uses. Furthermore, it is not intended to be bound by any express or implied theory set forth in the foregoing technical field, background art, summary of the invention, or the following detailed description. It should be understood that throughout the drawings, corresponding reference numerals denote the same or corresponding parts and features.

[0031] Several examples of this disclosure will now be described in detail with reference to the accompanying drawings. In the drawings and description, the same or similar reference numerals are used wherever possible to refer to the same or similar parts or steps. The drawings are presented in a simplified form and are not drawn to scale. The following description is exemplary in nature only and is not intended to limit the disclosure, its application, or its uses.

[0032] The fast-charging capability of power batteries is becoming increasingly important. Although many batteries have a single-cycle charging capacity of 8C or 10C, their performance deteriorates rapidly under 100% fast-charging conditions, at least in part due to lithium (Li) deposition. By utilizing a solid electrolyte interface layer that promotes uniform lithium (Li) deposition, the vehicle battery cell disclosed in this paper improves the reversibility of lithium (Li) deposition and overall battery cell performance under harsh charging conditions.

[0033] refer to Figure 1 According to this disclosure, a perspective view of a vehicle 10 having a battery pack 12 is shown. The battery pack 12 is shown together with the exemplary vehicle 10. The vehicle 10 is an electric vehicle or a hybrid vehicle having wheels 14 driven by at least one electric motor / inverter 16. The electric motor / inverter 16 receives power from the battery pack 12. Although the vehicle 10 is shown as a passenger road vehicle, it should be understood that the battery pack 12 can be used in a variety of other types of transportation. For example, the battery pack 12 can be used in marine vehicles such as boats, or aircraft such as drones or passenger planes. Furthermore, the battery pack 12 can be used as a stationary power source separate and independent of the vehicle. The battery pack 12 includes a housing 18 for carrying and supporting a plurality of battery cells 20. In one example, the battery pack 12 may have fifty or more battery cells 20.

[0034] As used herein, the term "vehicle / transportation vehicle / mount" is not limited to motor vehicles. While this article primarily describes the technology in conjunction with electric and hybrid electric vehicles, the technology is not limited to electric and hybrid electric vehicles. These concepts can be broadly applied to a variety of applications, such as those related to components used in motorcycles, mopeds, locomotives, aircraft, ships, and other vehicles, as well as other battery-powered applications, such as portable power stations, for example, power stations supplying power to remote construction sites, emergency backup power, and permanent power stations associated with buildings and equipment, all of which can be powered by, for example, solar or wind power systems, power grids, and fuel-based generators (such as gasoline, propane, kerosene, or diesel generators and Stirling engines).

[0035] Figure 2 and Figure 3 It shows Figure 1 A battery cell 20 is shown within the battery pack 12. The battery pack 12 and battery cell 20 are understood as rechargeable batteries, capable of discharging under load and charging under external power. Battery cell 20 can be, for example, a pouch cell or a prismatic cell. Alternatively, battery cell 20 can be a cylindrical cell.

[0036] Figure 1 Each battery cell 20 disposed within the battery pack 12 shown has at least one electrode stack 22, which further includes an anode 24 disposed on an anode current collector 26, a cathode 28 disposed on a cathode current collector 30, and a separator 32 separating the anode 24 and the cathode 28. Each battery cell 20 may have dozens or hundreds of electrode stacks 22.

[0037] Electrode stack 22 is placed within housing 18, which is filled with electrolyte 34. During discharge, when a load is applied to battery cell 20, lithium ions (Li... + Electrons (e) move from the anode 24 through the diaphragm 32 to the cathode 28 via the electrolyte 34. - Lithium ions (Li) move from cathode 28 to anode 24 through the battery circuit to provide energy to the battery load. During charging, when an external voltage is applied, lithium ions (Li) move from cathode 28 to anode 24 to provide energy to the battery load. + The electrolyte 34 passes through the diaphragm 32 and moves from the cathode 28 to the anode 24, and can be embedded in the anode 24.

[0038] Although the illustrated battery cell 20 includes an anode 24 (and an anode current collector 26) and a cathode 28 (and a cathode current collector 30), the battery cell 20 may also include two or more cathodes 28 (and cathode current collectors 30) and one or more anodes 24 (and anode current collectors 26). In a further alternative embodiment, the battery cell 20 may include one or more cathodes 28 (and cathode current collectors 30) and two or more anodes 24 (and anode current collectors 26).

[0039] The anode current collector 26 may be a thin metal sheet or foil disposed on one side of each electrode stack 22 and / or housing 18, typically with a thickness between 0.005 and 1 mm. The anode current collector 26 may be made of, for example, copper or aluminum and connected to the electrode stack 22 to transmit current to an external circuit (not shown). In other examples, the anode current collector 26 may comprise copper-clad aluminum, nickel, titanium, stainless steel, and / or other suitable materials. Although the anode current collector 26 is shown in foil form, it should be understood that it may take other forms, such as mesh or composite materials.

[0040] Still refer to Figure 2 and Figure 3 The anode 24 is disposed on the anode current collector 26 and includes a material capable of reversibly inserting or embedding lithium ions at a lower electrochemical potential than that of the cathode 28, thereby creating an electrochemical potential difference between the anode 24 and the cathode 28. The anode 24 may include one or more carbon-based materials, such as graphite, activated carbon, carbon black and graphene, silicon, silicon carbide (SiC), graphite and silicon-carbon composites, silicon-based alloys, silicon oxides, silicon-based composites, tin oxides, aluminum, indium, zinc, germanium and / or titanium oxides, and any combination thereof. In one example, the anode 24 does not include lithium (Li). In some embodiments, the thickness of the anode 24 may range from 10 micrometers to 200 micrometers, including all values ​​and ranges therein.

[0041] Reference Figure 3 An example of a vehicle battery cell 20 is shown. In this example, a solid electrolyte interface (SEI) layer 36 is disposed on the anode 24. The SEI layer 36 contains Li3N components. The solid electrolyte interface layer 36 is formed during the initial charging cycle and contains decomposition products from the electrolyte 34.

[0042] Reference Figure 2 and Figure 3Electrolyte 34 provides a medium between cathode 28 and anode 24 through which lithium ions are transported. This medium can be a liquid or a gel and is capable of conducting lithium ions between cathode 28 and anode 24. Electrolyte 34 permeates the pores of porous membrane 32 and wets or otherwise contacts the surfaces of cathode 28 and anode 24, as well as membrane 32. In some embodiments, electrolyte 34 comprises one or more lithium salts dissolved in a non-aqueous organic solvent. Some examples of lithium salts may include one or more of the following: lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrachloroaluminate (LiAlCl4), lithium iodide (LiI), lithium bromide (LiBr), lithium thiocyanate (LiSCN), lithium tetrafluoroborate (LiBF4), lithium tetraphenylborate (LiB(C6H5)4), lithium bis(oxalate)borate (LiB(C2O4)2)(LiBOB), and lithium difluorooxalateborate. The electrolytes are lithium hexafluoroarsenate (LiBF2(C2O4)), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethane)sulfonylimide (LiN(CF3SO2)2), lithium bis(fluorosulfonylimide) (LiN(FSO2)2)(LiSFI), lithium bis(triethylene glycol dimethyl ether)bis(trifluoromethanesulfonylimide) (Li(G3)(TFSI)) and / or lithium bis(trifluoromethanesulfonyl)aza (LiTFSA). In one example, the electrolyte is a liquid electrolyte comprising lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonylimide) (LiFSI), wherein the concentration of lithium nitrate is 0.5 wt.%. In another example, the electrolyte is a liquid electrolyte comprising lithium hexafluorophosphate (LiPF6) and lithium bis(fluorosulfonylimide) (LiFSI), wherein the concentration of lithium nitrate is 0.6 wt.%.

[0043] The Li3N-containing SEI layer 36 can be formed by adding nitrates, nitrites, and / or lithium nitrides to the electrolyte 34, in an amount sufficient to promote the formation of a uniform bulk lithium deposition morphology on the anode 24 during fast charge cycling. Fast charge (XFC) cycling refers to the process of rapidly charging a battery, for example, aiming to charge it to 80% of its capacity in a very short time (e.g., 10-15 minutes). This is particularly important for electric vehicles (e.g., vehicle 10), as reducing charging time is crucial for convenience and wider adoption.

[0044] Some examples of nitrates suitable for addition to electrolyte 34 may include lithium nitrate (LiNO3), potassium nitrate (KNO3), sodium nitrate (NaNO3), and tetramethylammonium nitrate ((CH3)4N). + NO3 - Tetraethylammonium nitrate ((C2H5)4N) + NO3 -), tetrapropylammonium nitrate ((C3H7)4N + NO3 - And / or isosorbide dinitrate (C6H8N2O8). In an example using lithium nitrate (LiNO3), the concentration of lithium nitrate (LiNO3) is between 0.2 and 2.0 wt.%. Some examples of nitrites suitable for addition to electrolyte 34 may include lithium nitrite (LiNO2), sodium nitrite (NaNO2), and / or potassium nitrite (KNO2). When using a suspended electrolyte, the suspended electrolyte may include lithium nitride (Li3N) nanoparticles. The size of the nanoparticles may be between 10 and 500 nanometers (nm). When Li3N is generated in situ in SEI layer 36 by adding nitrates or nitrites, the generated Li3N can have a smaller size and a more uniform distribution.

[0045] Compared to batteries with an SEI layer that does not contain Li3N, the uniform bulk lithium deposition morphology formed using nitrate, nitrite and / or suspended electrolytes is characterized by a reduced tendency for whisker-like lithium growth, thereby improving the reversibility of lithium deposition and stripping during XFC cycling.

[0046] like Figure 3 As shown, a separator 32 is disposed on the SEI layer 36. The separator 32 can be a porous material formed of an electrically insulating material, which prevents contact between the cathode 28 and the anode 24, thus avoiding potential short circuits in the battery circuit. The separator 32 is sandwiched between, or at least partially surrounds, the cathode 28 and the anode 24, allowing lithium ions and electrolyte 34 to pass through the pores of the separator 32. The separator 32 may comprise one or more of composite materials, polymeric materials, or nonwoven materials. In any of the above designs, one or more separators 32 are staggered between the cathode 28 and the anode 24 to prevent contact between them. In some embodiments, the separator 32 comprises at least one of polyethylene, polypropylene, polyamide, polytetrafluoroethylene, polyvinylidene fluoride, and polyvinyl chloride. Furthermore, the separator 32 may be filled, i.e., contain a filler dispersed therein, wherein the filler includes materials such as glass fiber. In additional or alternative embodiments, the separator 32 may comprise at least one of a thermally stable porous polymer coating and a ceramic coating, such as an alumina coating. The coating may be applied to one or more surfaces of a porous polymer membrane, which may include at least one of polyethylene and polypropylene. The diaphragm 32 may comprise one or more layers, each layer being formed of one or more of the aforementioned materials. The diaphragm 32 may be in the form of a thin film or a mesh, such as a woven mesh or a slit film. In some embodiments, the thickness of the diaphragm 32 is in the range of 4 micrometers to 25 micrometers, including all values ​​and ranges therein.

[0047] like Figure 2 and Figure 3 As shown, cathode 28 is disposed on diaphragm 32. Cathode 28 may include cathode active material configured to provide lithium ions (Li ions). + The cathode source allows for the reversible insertion or intercalation of lithium ions, which, for example, determines the battery's capacity and average voltage. The cathode active material may include, for example, lithium iron phosphate (LFP). In other examples, the cathode 28 may include at least one of lithium cobalt oxide (LCO), lithium nickel manganese cobalt oxide (NMC), lithium nickel cobalt aluminum oxide (NCA), or lithium manganese oxide (LMO). It should be understood that the cathode 28 may also include other commercially available materials.

[0048] like Figure 2 and Figure 3 As shown, a cathode current collector 30 is disposed on the cathode 28. The cathode current collector 30 may be a thin metal plate or foil disposed on one side of each electrode stack 22 and / or housing 18, and its thickness is typically between 0.005 and 1 mm. The cathode current collector 30 may be made of, for example, copper or aluminum, and is connected to the electrode stack 22 to transmit current to an external circuit (not shown).

[0049] Figure 4 It shows the method for forming Figure 2 and Figure 3 Method 400 for the battery cell shown. Method 400 begins at step 402.

[0050] Step 402 describes applying cathode 28 onto cathode current collector 30. The cathode material is typically a mixture of active material, binder, and conductive additives, prepared in slurry form. The slurry is then uniformly coated onto cathode current collector 30. The slurry can then be dried to remove solvents and ensure good adhesion of the cathode material to cathode current collector 30. The dried slurry forms cathode 28, which can then be calendered.

[0051] Step 404 describes applying the anode 24 onto the anode current collector 26. The anode material is typically a mixture of an active material (such as graphite), a binder, and conductive additives, prepared in slurry form. The slurry is then uniformly coated onto the anode current collector 26. The slurry can then be dried to remove the solvent and ensure good adhesion of the anode material to the anode current collector 26. The dried slurry forms the anode 24, which can then be calendered.

[0052] Step 406 describes positioning the separator 32 between the cathode 28 and the anode 24. Step 408 describes assembling the cathode 28, anode 24, and separator 32 into the battery housing 18. The positioning and assembly steps can be performed using a stacking machine or a winding machine.

[0053] Step 410 describes adding electrolyte 34 to the battery cell housing 18. Electrolyte 34 is in contact with the cathode 28, anode 24, and separator 32. Electrolyte 34 includes at least one of lithium-based additives, nitrates, or nitrites. Electrolyte 34 can be added to the battery cell housing using an electrolyte filling machine. Step 412 describes sealing the battery cell housing 18. Battery cell housing 18 can be sealed using a sealing machine.

[0054] Step 414 describes charging and discharging the battery cell 20 during the formation process to form a uniform bulk-deposited solid electrolyte interphase (SEI) layer 36 on the surface of the anode 24. At least one of a lithium-based additive, a nitrate, or a nitrite promotes the formation of the SEI layer 36, and the SEI layer 36 comprises lithium nitride (Li3N). The charging and discharging of the battery cell 20 can be performed using a formation tester and / or a aging chamber.

[0055] The vehicle battery cell 20 and method 400 disclosed herein have advantages and benefits over the prior art. By utilizing a solid electrolyte interface layer 36 that promotes uniform deposition of lithium (Li) on the anode 24, the vehicle battery cell 20 disclosed herein improves the reversibility of lithium (Li) and the overall battery cell performance under harsh charging conditions.

[0056] This description is merely illustrative and is not intended to limit this disclosure, its application, or its use. The broad teachings of this disclosure can be implemented in many forms. Therefore, although this disclosure contains specific examples, its true scope should not be limited thereto, as other modifications will become apparent upon examination of the drawings, description, and claims.

Claims

1. A vehicle battery cell, comprising: Anode current collector; An anode, which is disposed on the anode current collector; A solid electrolyte interface layer is disposed on the anode; A separator disposed on the solid electrolyte interface layer, wherein the separator comprises lithium nitride (Li3N), wherein the lithium nitride (Li3N) induces lithium to be uniformly deposited on the anode; Cathode, which is disposed on the diaphragm; and A cathode current collector is disposed on the cathode.

2. The vehicle battery cell according to claim 1, wherein, The anode includes at least one of graphite, silicon carbide (SiC), or silicon oxide (SiOx).

3. The vehicle battery cell according to claim 1, wherein, The cathode comprises at least one of lithium cobalt oxide (LCO), lithium nickel manganese cobalt oxide (NMC), lithium nickel cobalt aluminum oxide (NCA), lithium iron phosphate (LFP), or lithium manganese oxide (LMO).

4. The vehicle battery cell according to claim 1, wherein, The cathode comprises lithium iron phosphate (LFP), and the anode comprises graphite.

5. The vehicle battery cell according to claim 1, wherein, The cathode comprises lithium iron phosphate (LFP), and the anode comprises a graphite and silicon-carbon composite anode.

6. A vehicle comprising: Multiple battery cells assembled together, each battery cell including Anode current collector; An anode, which is disposed on the anode current collector; A solid electrolyte interface layer is disposed on the anode; A separator disposed on the solid electrolyte interface layer, wherein the separator comprises lithium nitride (Li3N), wherein the lithium nitride (Li3N) induces lithium to be uniformly deposited on the anode. Cathode, which is disposed on the diaphragm; and A cathode current collector is disposed on the cathode.

7. The vehicle according to claim 6, wherein, The anode includes at least one of graphite, silicon carbide (SiC), or silicon oxide (SiOx).

8. The vehicle according to claim 6, wherein, The cathode comprises lithium iron phosphate (LFP), and the anode comprises graphite.

9. The vehicle according to claim 6, wherein, The cathode comprises lithium iron phosphate (LFP), and the anode comprises a graphite and silicon-carbon composite anode.

10. The vehicle according to claim 6, wherein, The battery is a pouch cell battery.

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