Negative electrode assembly for lithium metal battery, lithium metal battery prepared therefrom and related method

Abstract

The present invention relates to a negative electrode assembly for a lithium metal battery, a lithium metal battery prepared therefrom, and related methods. A negative electrode assembly sheet comprising a lithium metal layer sandwiched between a pair of separator layers to simplify the handling of lithium metal, thereby facilitating the assembly of a fast and efficient stacked core. In some embodiments, the separator layer is pressure laminated to the lithium metal layer without any adhesive. In some embodiments, the stacked core is manufactured by stacking the negative electrode assembly sheets alternately with the positive electrode sheets. In some embodiments, before laminating one or more separators to the lithium metal layer, a functional coating beneficial to the lithium metal layer is provided to one or more separator layers. A lithium metal battery made using a stacked core manufactured according to aspects of the present disclosure is also described.

Description

[0001] Related application data

[0002] This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 812,472, filed on March 1, 2019, entitled “NEW STACK JELLY-ROLL STRUCTURE USING LAMINATION ON LITHIUM-METAL ANODE,” and U.S. Provisional Patent Application No. 62 / 830,620, filed on April 8, 2019, entitled “NEW STACK JELLY-ROLL STRUCTURE USING LAMINATION ON LITHIUM-METAL ANODE,” and U.S. Provisional Patent Application No. 62 / 832,665, filed on April 11, 2019, entitled “NEW STACK JELLY-ROLL STRUCTURE USING LAMINATION ON LITHIUM-METAL ANODE,” each of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention generally relates to the field of electrochemical devices. In particular, the present invention relates to negative electrode assemblies for lithium metal batteries, lithium metal batteries prepared therefrom, and related methods. Background Art

[0004] Due to their high gravimetric and volumetric energy density, lithium metal batteries have the potential to become the battery of choice for many applications that require such properties, including electric vehicles and mobile electronic devices, among others. However, the manufacture of lithium metal batteries presents challenges that must be overcome to make the cost of producing lithium metal batteries economically viable. Some of the challenges stem from the inherent properties of lithium metal. Lithium metal is a pyrophoric metal that is challenging to work with due to its "stickiness," lightness, and softness, especially in large-scale production situations, and particularly when handling and processing thin layers (e.g., less than 20 microns), which may be ideal for use in commercial-grade lithium metal batteries. Summary of the invention

[0005] In some aspects, the present disclosure relates to a method for manufacturing a lithium metal battery. The method includes: assembling a stacked jellyroll, the assembling of the stacked jellyroll including: providing a plurality of negative electrode assembly sheets, each of which includes a lithium metal layer pressure-laminated between a first separator and a second separator; providing a plurality of positive electrode sheets; and alternately stacking the negative electrode assembly sheets and the plurality of positive electrode sheets with each other to form the stacked jellyroll.

[0006] In one or more embodiments of the method, a negative electrode assembly sheet is formed, wherein the forming includes: forming a laminate web including a first separator, a lithium metal layer, and a second separator; and cutting the laminate web to form the negative electrode assembly sheet.

[0007] In one or more embodiments of the method, forming the laminated web includes contacting the first separator and the second separator with lithium metal to form a multilayer structure, and applying pressure to the multilayer structure to form the laminated web.

[0008] In one or more embodiments of the method, applying pressure to the multilayer structure includes conveying the multilayer structure through nip rollers.

[0009] In one or more embodiments of the method, the first separator includes a functional coating for the lithium metal layer, and the functional coating is in contact with the lithium metal layer.

[0010] In one or more embodiments of the method, the functional coating comprises a ceramic material.

[0011] In one or more embodiments of the method, the functional coating includes lithium fluoride.

[0012] In one or more embodiments of the method, the functional coating comprises lithium carbonate.

[0013] In one or more embodiments of the method, a negative electrode assembly sheet is formed, wherein the forming comprises: forming a laminated web comprising a first separator, a lithium metal layer, and a second separator; wherein the first separator comprises a functional coating in contact with the lithium metal layer; and cutting the laminated web to form the negative electrode assembly sheet.

[0014] In one or more embodiments of the method, forming the laminated web includes contacting the first separator and the second separator with lithium metal to form a multilayer structure, and applying pressure to the multilayer structure to form the laminated web.

[0015] In one or more embodiments of the method, a functional coating is applied to a porous separator body to form a first separator.

[0016] In one or more embodiments of the method, the functional coating comprises a ceramic material.

[0017] In one or more embodiments of the method, the functional coating includes lithium fluoride.

[0018] In one or more embodiments of the method, the functional coating comprises lithium carbonate.

[0019] In one or more embodiments of the method, applying pressure to the multilayer structure includes conveying the multilayer structure through nip rollers.

[0020] In one or more embodiments of the method, the stacked cores are placed inside a housing.

[0021] In one or more embodiments of the method, an electrolyte is added to the interior of the housing and the housing is sealed.

[0022] In one or more embodiments of the method, the lithium metal layer has a thickness of less than 20 microns.

[0023] In one or more embodiments of the method, the lithium metal layer has a thickness of less than 10 microns.

[0024] In one or more embodiments of the method, the lithium metal layer has a sheet-shaped region, and the negative electrode assembly sheet further includes a current collector layer in contact with the lithium metal layer across the sheet-shaped region.

[0025] In one or more embodiments of the method, the current collector layer is embedded in the lithium metal layer such that lithium metal is present on both sides of the current collector layer.

[0026] In some aspects, the present disclosure relates to a method of manufacturing a negative electrode assembly. The method includes providing a lithium metal layer having a first side and a second side opposite to the first side; providing a first separator having a functional coating for the lithium metal layer; contacting the functional coating and the first side of the lithium metal layer with each other; and pressure laminating the first separator and the lithium metal layer to each other to form a negative electrode assembly.

[0027] In one or more embodiments of the method, a functional coating is applied to a porous separator body to form a first separator.

[0028] In one or more embodiments of the method, pressure lamination uses nip rolls.

[0029] In one or more embodiments of the method, the method is performed in a roll-to-roll process.

[0030] In one or more embodiments of the method, the functional coating comprises a ceramic material.

[0031] In one or more embodiments of the method, the functional coating includes lithium fluoride.

[0032] In one or more embodiments of the method, the functional coating comprises lithium carbonate.

[0033] In one or more embodiments of the method, a second separator is provided; the second separator and the second side of the lithium metal layer are brought into contact with each other; and the first separator, the lithium metal layer, and the second separator are pressure laminated to each other to form a negative electrode assembly.

[0034] In one or more embodiments of the method, the lithium metal layer has a sheet-shaped region, and the negative electrode assembly sheet further includes a current collector layer in contact with the lithium metal layer across the sheet-shaped region.

[0035] In one or more embodiments of the method, the current collector layer is embedded in the lithium metal layer such that lithium metal is present on both sides of the current collector layer.

[0036] In some aspects, the present disclosure relates to a negative electrode assembly comprising a lithium metal layer having a first side and a second side opposite to the first side; and a first separator having a surface and a functional coating for the lithium metal layer on the surface, wherein the first separator is pressure laminated to the lithium metal layer on the first side of the lithium metal layer having the functional coating in contact with the lithium metal layer.

[0037] In one or more embodiments of the negative electrode, the functional coating includes a ceramic material.

[0038] In one or more embodiments of the negative electrode, the functional coating includes lithium fluoride.

[0039] In one or more embodiments of the negative electrode, the functional coating includes lithium carbonate.

[0040] In one or more embodiments of the negative electrode, the lithium metal layer has a thickness of less than 20 microns.

[0041] In one or more embodiments of the negative electrode, the lithium metal layer has a thickness of less than 10 microns.

[0042] In one or more embodiments of the negative electrode, the second separator is pressure-laminated with the lithium metal layer on the second side of the lithium metal layer.

[0043] In one or more embodiments of the negative electrode, the lithium metal layer has a sheet-shaped region, and the negative electrode assembly sheet further includes a current collector layer contacting the lithium metal layer across the sheet-shaped region.

[0044] In one or more embodiments of the negative electrode, the current collector layer is embedded in the lithium metal layer such that lithium metal is present on both sides of the current collector layer.

[0045] In some aspects, the present disclosure relates to a lithium metal battery, comprising: a magnetic core body, the magnetic core body including a plurality of negative electrode component sheets and a plurality of positive electrode sheets stacked alternately with the negative electrode component sheets; wherein each negative electrode component sheet includes: a lithium metal layer having a first side and a second side opposite to the first side; a first separator pressure-laminated to the lithium metal layer on the first side of the lithium metal layer; and a second separator pressure-laminated with the lithium metal layer on the second side of the lithium metal layer; an electrolyte solution; and a shell containing the magnetic core body and the electrolyte solution so that the electrolyte solution saturates the first separator and the second separator of the negative electrode component sheet.

[0046] In one or more embodiments of the lithium metal battery, the first separator includes a functional coating for the lithium metal layer, and the first separator layer is pressure laminated to the lithium metal layer such that the functional coating is in contact with the lithium metal layer.

[0047] In one or more embodiments of the lithium metal battery, the functional coating comprises a ceramic material.

[0048] In one or more embodiments of the lithium metal battery, the functional coating includes lithium fluoride.

[0049] In one or more embodiments of the lithium metal battery, the functional coating comprises lithium carbonate.

[0050] In one or more embodiments of the lithium metal battery, the lithium metal layer has a thickness of less than 20 microns.

[0051] In one or more embodiments of the lithium metal battery, the lithium metal layer has a thickness of less than 10 microns.

[0052] In one or more embodiments of the lithium metal battery, the lithium metal layer has a sheet-shaped region, and the negative electrode assembly sheet further includes a current collector layer in contact with the lithium metal layer across the sheet-shaped region.

[0053] In one or more embodiments of the lithium metal battery, the current collector layer is embedded in the lithium metal layer such that lithium metal is present on both sides of the current collector layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] For the purpose of illustrating embodiments of the invention, the accompanying drawings show aspects of one or more implementations of the invention. However, it should be understood that the invention is not limited to the precise arrangements and instrumentalities shown in the accompanying drawings, in which:

[0055] FIG. 1 is a diagram showing a conventional zigzag folding stacking process for preparing a zigzag folding stacked roll core for a lithium metal battery;

[0056] Figure 2Ais a diagram showing an exemplary direct stacking process for preparing a direct stacked jellyroll core for a lithium metal battery, wherein the stacking process includes alternately stacking negative electrode assembly sheets and positive electrode sheets on each other;

[0057] Figure 2B yes Figure 2A An enlarged partial cross-sectional view of one embodiment of a negative electrode assembly sheet showing a first separator layer and a second separator layer being pressure laminated to a lithium metal layer;

[0058] Figure 2C is a diagram showing an exemplary method for preparing a negative electrode assembly web, the negative electrode assembly web being Figure 2A and Figure 2B A precursor of a negative electrode component sheet;

[0059] Figure 2D yes Figure 2A A partially enlarged cross-sectional view of an embodiment of a positive electrode sheet;

[0060] Figure 2E is a partially enlarged cross-sectional view of an alternative negative electrode assembly sheet including a current collector layer according to an embodiment;

[0061] Figure 3A is an exploded side view of an exemplary negative electrode assembly sheet including a functional coating for a lithium metal layer applied to at least one separator layer prior to pressure lamination of one or more separator layers and the lithium metal layer to one another;

[0062] Figure 3B One or more separator layers and lithium metal layers are laminated to each other under pressure. Figure 3A A longitudinal cross-sectional view of a negative electrode assembly sheet;

[0063] Figure 3C The precursor negative electrode assembly web is shown as being made into Figure 3B A diagram of a method of manufacturing a negative electrode assembly sheet; and

[0064] Figure 4 is a cross-sectional view of an exemplary lithium metal battery having directly stacked jellyrolls prepared according to the present disclosure. DETAILED DESCRIPTION

[0065] In some aspects, the present disclosure relates to methods for making directly stacked rolls for lithium metal batteries, and preparing lithium metal batteries using such stacked rolls. In some aspects, the present disclosure relates to stacked rolls and the battery itself. In some aspects, the present disclosure relates to a method for preparing a negative electrode assembly having one or more functional coatings for pre-coating a lithium metal layer to one or more separators before contacting the lithium metal layer with the functional coating to prepare the negative electrode assembly. In some aspects, the present disclosure relates to such a negative electrode assembly itself. Examples of these and other methods are shown below. Note that although the embodiments presented in the present disclosure are primarily directed to lithium metal batteries having lithium metal negative electrodes, general methods, techniques, structures, etc. are applicable to other lithium metal-based electrochemical devices, such as supercapacitors. In addition, the lithium metal in any of the present embodiments and implementations may be replaced by one or more other active alkali metals, such as sodium magnesium and / or aluminum, and any suitable alloys thereof.

[0066] Embodiment of direct stacked cores

[0067] FIG1 depicts a conventional stacking process 100 for making stacked cores for lithium metal batteries. The conventional stacking process 100 includes alternately stacking positive electrode sheets 104 and negative electrode sheets 108 while feeding a continuous separator web 112 from a roll 112A to form a stacked core 116, wherein a portion of the separator web is sandwiched between each pair of positive and negative electrode sheets. Stacking is achieved by alternately adding individual positive and negative electrode sheets 104 and 108 (the additions are represented by arrows 120(1) and 120(2), respectively), and moving one, the other, or both of the growing stacked cores 116 and rolls 112A back and forth (in this embodiment, arrow 124 represents the back and forth movement of the stacked cores) so that the separator web 112 is wrapped around one side of each positive and negative electrode sheet and sandwiched between the pairs of positive and negative electrode sheets as the stacking is performed. As one would readily appreciate, due to the zig-zag shape of the continuous separator web 112 in the finished stacked core 116, this process is often referred to as a "zig-zag shape stacking process" or a "Z-fold stacking process".

[0068] The machine (not shown) required for performing this conventional stacking process 100 is quite complex, not only because the machine needs to move the stacked core 116 and / or roll 112A of the continuous separator web 112 to form a zigzag structure, but also because the machine needs to place the positive and negative electrode sheets 104 and 108 respectively into the growing stack to coordinate this operation. For contemporary and future lithium metal batteries that utilize relatively thin lithium metal layers (e.g., on the order of 20 microns or 10 microns or less), the machine used to perform the conventional zigzag folding stacking process (e.g., the conventional stacking process 100 of Figure 1) must also be designed to handle extremely precise lithium metal negative plates. As described in the background section above, lithium metal has many physical properties that make its handling and processing extremely challenging. In fact, the brittleness of contemporary and future lithium metal negative electrodes usually requires specialized components and requires limiting the speed of mechanical operation. This fact and the complexity of the operation are accompanied by the complexity of the machine, causing the machine to spend considerable time to complete the stacking process of each stacked core it manufactures.

[0069] Figure 2A An exemplary direct stacking method 200 is shown that can be used to manufacture a direct stacked core 204. As will be apparent from reading this section, a machine (not shown) used to perform the direct stacking method 200 is far less complex than a machine used to perform the Z-folding process of the conventional stacking method 100 of FIG. 1 . This is so because the machine used for the direct stacking method 200 does not provide separators as a component for separation and differentiation during the stacking process. Therefore, no separator handling components are required, nor are actuators and / or other components / features for moving the stacked core 116 ( FIG. 1 ) and / or separator roll 112A ( FIG. 1 ). In addition, and as described below, a machine for Figure 2B The direct stacking method 200 machine does not directly process lithium metal anodes and therefore does not need to be specially designed to handle the brittleness of such anodes.

[0070] Reference Figure 2A , the exemplary direct stacking method 200 involves alternatingly adding only two types of components to a growing stacked jellyroll 204, namely, positive electrode sheets 208 and negative electrode assembly sheets 212 (the additions are represented by arrows 216(1) and 216(2), respectively). Stacking only two types of components on top of each other greatly simplifies the process of manufacturing jellyrolls for stacking batteries, particularly lithium metal batteries and other types of active metal batteries.

[0071] This highly simplified stacking process of the direct stacking method 200 can be achieved by configuring the negative electrode assembly sheet 212 as follows: Figure 2BAs shown, the negative electrode assembly sheet 212 includes a lithium metal layer 212A sandwiched between two separator layers 212B and 212C. It should be noted that for convenience, in this document and the appended claims, the two separators 212B and 212C may also be referred to as "first separator" or "first separator layer" and "second separator" or "second separator layer", respectively. In these terms, "first" and "second" have no meaning, except to provide a convenient way to identify the two, that is, to separate them from each other. Figure 2C As shown in , in some embodiments, for example, in a continuous web forming process 220, separator layers 212B and 212C are pressure laminated to lithium metal layer 212A using nip rollers, such as nip rollers 224(1) and 224(2). The nip rollers 224(1) and 224(2) and / or their corresponding supporting machinery (not shown) are adjusted to provide a certain amount of pressure sufficient to adhere separator layers 212B and 212C to lithium metal layer 212A. Typically, the adhesion is a direct adhesion of separator layers 212B and 212C to lithium metal layer 212A; no separate adhesive or other adhesive is used for direct adhesion. This direct adhesion is facilitated by the relative softness of the lithium metal in the lithium metal layer. In some embodiments, the pressure and temperature ranges for optimal results are 10°C to 60°C and 100 lbf / in (175N / cm) to 1000 lbf / inch (1750N / cm), respectively. Generally, the optimal values ​​typically depend on the material being coated.

[0072] exist Figure 2C In the continuous web forming process 220 shown, lithium metal layer 212A is paid out from lithium metal roll 212A(R), and each of first and second separator layers 212B and 212C are paid out from first separator roll 212B(R) and second separator roll 212C(R), respectively. As layers 212A, 212B, and 212C are paid out, they are brought into contact with one another and pressed by nip rolls 224(1) and 224(2), so that they are pressure laminated to one another or to one another, thereby forming a continuous negative electrode assembly web 228. Negative electrode assembly web 228 may then be cut, such as by punching, die cutting, shearing, etc., to form Figure 2A Anode assembly sheet 212 for direct stacking process 200.

[0073] refer to Figure 2B As known to those skilled in the art, each of the first and second separator layers 212B and 212C, in the stacked roll core 204, is connected between the negative electrode (herein the lithium metal layer 212A) and the positive electrode (herein one of the positive electrode sheets 208 ( Figure 2A)) provides physical and electrical separation between the negative electrode and the positive electrode while allowing ions to flow in the electrolyte (not shown) between the negative electrode and the positive electrode. Each of the separator layers 212B and 212C can be made of any suitable material, such as a mixture of polyethylene, polypropylene and / or ceramic mixed polyolefin materials, and any combination thereof, etc. Although not shown, in some embodiments, each of the separator layers 212B and 212C can have a thermal shutdown capability. In some embodiments, the thickness of each separator layer 212B, 212C can be in the range of 10 μm to 30 μm, although other thicknesses can be used to suit a particular design. As described above, a negative electrode assembly sheet such as the negative electrode assembly sheet 212 using a separator layer adhered to a lithium metal layer is particularly desirable for use with a lithium metal thin layer, such as a lithium metal layer having a thickness of 50 microns or less, 20 microns or less, or 10 microns or less. However, for other applications, the lithium metal layer 212A can be greater than 50 microns.

[0074] In one embodiment, each of the first and second separator layers 212B and 212C is made of an inorganic material (e.g., Al 2 O 3 ) and a porous mixture of polyethylene, providing a lithium metal layer 212A in the composite negative electrode assembly sheet 212, greatly increasing the convenience of handling the lithium metal layer. Lithium metal has an extremely low tensile modulus of 0.81 MPa, which is due to its physical softness (melting temperature is 180°C). After the lithium metal layer 212A is pressure-laminated with the first and second separator layers 212B and 212C, the tensile modulus of the composite negative electrode assembly sheet 212 is on the order of 30 MPa to 50 MPa, which is more than 2 orders of magnitude higher than the corresponding bare lithium metal negative electrode used in the conventional Z-shaped folding stacking process (e.g., the conventional stacking process 100 of FIG. 1).

[0075] In addition, bare lithium metal anodes are difficult to cut and stack due to their stickiness. During the cutting and stacking process, the bare lithium metal anodes tend to stick to the cutting and handling components of the cutting and stacking machines and are therefore easily damaged. Due to its brittleness, the cutting and handling machines need to be run at relatively low speeds to enhance the control of the very fragile lithium metal. However, when using anode component sheets, such as Figure 2A and 2B The negative electrode assembly sheet 212, the lithium metal (for example, the lithium metal layer 212A) is covered by the separator layer, where the separator layers 212B and 212C are on both sides of the lithium metal layer (for example, see Figure 2CThe first and second sides 212A(1) and 212A(2) of the negative electrode assembly sheet 212 are generally arranged across the entire sheet area. This minimizes the exposure of the lithium metal to the cutting, handling and stacking machinery, thereby minimizing harmful interactions between the lithium metal and such machinery. Combined with the robustness of the negative electrode assembly sheet 212, this allows the machinery to be operated at higher speeds than machinery that handles bare lithium metal negative electrodes, such as in conventional stacking processes. The following table shows the direct stacking process of the present disclosure (e.g. Figure 2A The benefits of higher speed operation and simplified stacking of the direct stacking process 200) are provided compared to conventional Z-fold stacking processes such as the conventional process 100 of FIG. 1.

[0076]

[0077]

[0078] It can be seen from the above table that in this embodiment, when the composite positive electrode assembly sheet of the present disclosure is used, for example Figure 2A and Figure 2B The negative electrode assembly sheet 212 of the present invention increases the speed of cutting the negative electrode structure by three times. The table also shows that when a direct stacked roll core with 23 negative electrodes and 24 positive electrodes is manufactured using the composite negative electrode assembly sheet of the present invention, the stacking speed is ten times faster than when a conventional bare lithium metal negative electrode is used.

[0079] refer to Figure 2A and 2B Each positive electrode sheet 208 may be made of any material suitable for providing a positive electrode that is compatible with the lithium metal-based negative electrode assembly sheet 212 and the particular electrolyte used in the final battery (not shown) utilizing the stacked jellyroll core 204. Figure 2D In one example shown, each positive electrode sheet 208 includes an aluminum foil layer 208A as a positive electrode substrate. Both sides of the aluminum foil layer 208A are coated with a slurry containing high nickel NMC811 (88% lithium nickel, 11% manganese and 11% cobalt), a polymer binder, (here polyvinylidene fluoride (PVDF)) and conductive carbon to provide an active positive electrode layer 208B on both sides of the foil layer. There is generally no limitation on the construction and manufacture of the positive electrode sheet 208 except for the applicability of the specific chemical substances discussed.

[0080] It should be noted that although Figure 2CA particular arrangement of a pair of nip rollers 224(1) and 224(2) is shown, and those skilled in the art will readily appreciate that other arrangements are possible, including arrangements that include more than one set of nip rollers. For example, one or more additional sets of nip rollers may be provided that sequentially increase the pressure applied to the negative electrode assembly web 228. It should also be noted that pressure lamination may be performed in a manner other than using nip rollers. For example, a fixed press (not shown) may be used to pressure laminate the lithium metal layer 212A and the first and second separator layers 212B and 212C to each other. In this embodiment, the fixed press may be configured to pressure laminate the first and second separator layers 212B and 212C to the lithium metal layer 212A in discrete lengths. For example, the embodiments and reference Figure 2C , the three layers 212A, 212B, and 212C can be released from the respective rolls 212A(R), 212B(R), and 212C(R) to form a loose stack (not shown), which can then be pressed in a stationary press to form a negative electrode assembly web 228. In some embodiments, as described above, the negative electrode assembly web 228 can then be cut to form negative electrode assembly sheets 212( Figure 2A and 2B ).

[0081] Although Figure 2A and Figure 2B The exemplary negative electrode assembly sheet 212 has only a lithium metal layer 212A, and other embodiments may include one or more additional layers sandwiched between the first and second separator layers 212B and 212C. For example, Figure 2E A negative electrode assembly sheet 212' is shown, which includes a current collector layer 212D located within a lithium metal layer 212A. The current collector layer 212D can be made of any suitable conductive material, such as copper or aluminum, etc. In addition, depending on the specific design in question, the current collector can be solid or perforated. In some embodiments, an optional binder 212E ( Figure 2E ) can be used to assist in securing one or both of the separator layers 212B and 212C to the lithium metal layer 212A. The alternative negative electrode assembly sheet 212' can replace the negative electrode assembly sheet 212 in the direct stacking process 200 of FIG.

[0082] Incorporating embodiments of negative electrode assembly sheets having one or more additional layers, e.g. Figure 2E In the embodiment of the negative electrode assembly sheet, the negative electrode assembly sheet has a current collector layer 212D located between the first separator layer and the second separator layer 212B and 212C. For the sake of clarity, it is noted that various terms have specific meanings. Regarding the term "lithium metal layer", for convenience, the term should refer to the entire lithium metal present between the first separator layer and the second separator layer 212B and 212C. This Figure 2Bis straightforward in the context of an embodiment where each lithium metal layer 212A is the only layer between the first and second separator layers 212B and 212C ( Figure 2B ) or only on one side of the current collector layer 212D. However, despite the fact that when the current collector layer 212D is a solid layer, the lithium metal forms two discrete layers, one on each side of the current collector layer, the term "lithium metal layer" is considered to also apply to Figure 2E 212A, describing the total thickness of lithium metal sandwiched between the first and second separator layers 212B and 212C. In this case, each such separate lithium metal layer can be considered a sublayer and / or the current collector layer 212D can be considered embedded in the lithium metal layer 212A.

[0083] Example of an indirect functional coating for a lithium metal layer

[0084] Lithium metal and its oxide are not easily wetted by liquids having a surface tension exceeding 25 dynes / cm. Therefore, it is difficult to directly apply a functional coating beneficial to the lithium metal layer onto the lithium metal layer. Examples of functional coatings for lithium metal layers include ceramic coatings, lithium fluoride coatings, and lithium carbonate coatings. Figure 3A and 3B In order to improve this problem, the separator layer is laminated to the lithium metal layer 308 ( Figure 3A ), one or more functional coatings, such as functional coating 300, may be applied to separator layer 304. The coated separator layer 304' is then pressure laminated to lithium metal layer 308 to form negative electrode assembly 312 ( Figure 3B ), which may be a continuous mesh or sheet, depending on the situation. When in sheet form, the negative electrode assembly 312 may be used Figure 2A In the direct stacking process 200.

[0085] The process of applying a functional coating beneficial to a lithium metal layer, such as the functional coating 300 applied to the lithium metal layer 308, can be referred to as an "indirect coating process" because the functional coating is applied directly to the separator layer (here, separator layer 304), and then when the separator layer is pressure laminated onto the lithium metal layer, the functional coating ultimately contacts the lithium metal layer. Figure 3A and Figure 3B As shown, in some embodiments, the indirect coating process may include only a single (or "first") separator layer 304, which is pressure laminated to the lithium metal layer 308 on only one side of the lithium metal layer. However, as also shown, a second separator layer 316 may be optionally provided, with or without a second functional coating 320. In fact, one can easily imagine improved Figure 2CThe negative electrode assembly web forming process may include one or more coating applicators upstream of the nip rollers 224 (1) and 224 (2). Figure 3C This improved process is shown in FIG.

[0086] refer to Figure 3C , each of the first separator layer 304, the lithium metal layer 308 and the optional second separator layer 316 can be released from the corresponding rollers 304R, 308R and 316R. Prior to pressure lamination via a pair of nip rollers 324 (1) and 324 (2), one, the other or both of the first separator layer and the second separator layer 304 and 316 can be coated with at least one corresponding functional coating for the lithium metal layer 308, where one or more coating applicators are used for the functional coatings 300 and 320, respectively, and separate coating applicators 328 and 332 are used. Each coating applicator 328 and 332 can be of the same or different types. In some embodiments, where the functional coatings 300 and 320 are composed of the same material, separate applicators (not shown) can be used. Each of the coating applicators 328 and 332 can be of any suitable type, such as a sprayer, a brush applicator, a dip coater, etc., depending on the type of functional coating used as the functional coating 300 and 320, if any. For convenience only, coating applicators 328 and 332 are shown as sprayers.

[0087] In one specific example, nano-sized aluminum oxide (Al 2 O 3 , particle size D50 = 50nm) and one or more polymer binders, such as vinylidene fluoride and hexafluoropropylene copolymer (PVDF-HFP), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA) and / or carboxymethyl cellulose (CMC), etc., to prepare one, the other or both of the functional coatings 300 and 320. In some embodiments, the formulation of the aluminum oxide may be greater than 70% and less than 95%. The slurry may then be dried before further processing, such as pressure lamination as described below.

[0088] Examples of Lithium Metal Batteries Made Using Direct Stacked Jelly Rolls and / or Indirect Functional Coatings

[0089] Figure 4An exemplary lithium metal battery 400 is shown, made using a directly stacked core 404 manufactured according to aspects of the present disclosure. In this embodiment, the directly stacked core 404 is sealed in a housing (here, a pouch-type housing 408) together with a suitable electrolyte (not shown, but present at least in the separator layers 416B(1) and 416B(2)). In other embodiments, the pouch-type housing 408 may be replaced with other types of housings, such as rigid wall housings, etc. Fundamentally, the type of housing is important only to the extent that the necessary functions are provided, including providing a sealed space for accommodating the directly stacked core 404 and the electrolyte. Those skilled in the art are familiar with the techniques and materials used to construct the pouch-type housing 408 or other types of housings that a particular design may include. Therefore, it is not necessary for those skilled in the art to instantiate the lithium metal battery 400 without excessive experimentation, and further details of the housing are not required herein.

[0090] With respect to the electrolyte, since in this embodiment the battery 400 is a lithium metal battery, meaning that the negative electrode 416 comprises lithium metal, wherein lithium ions are deposited and stripped during the charge and discharge cycles, respectively, the electrolyte comprises lithium ions (not shown) that flow between the negative electrode and the positive electrode 420 within the directly stacked roll core 404 during the charge and discharge cycles. Thus, in this embodiment, the electrolyte comprises one or more lithium-based salts in a suitable form, such as a solution, a eutectic mixture, or a molten form, etc. In some embodiments, the electrolyte may comprise one or more solvents, one or more performance and / or performance enhancing additives, and / or one or more polymers, etc. The electrolyte may be in any suitable state of matter, such as a liquid, gel, or solid state. The composition of the electrolyte may be any composition suitable for the particular application in question, and may be determined by the designer of the particular instantiation of the lithium metal battery 400.

[0091] The negative electrode 416 is provided to the directly stacked jelly roll 404 in a negative electrode assembly sheet 416S, and the positive electrode is provided to the directly stacked jelly roll as a positive electrode sheet 420S. Each negative electrode assembly sheet 416S generally includes a lithium metal layer 416A (labeled in only one of the negative electrode assembly sheets 416S to avoid confusion; the others are the same) pressure-laminated between first and second separator layers 416B(1) and 416B(2), respectively. Each negative electrode assembly sheet 416S can be the same or similar to any of the negative electrode assembly sheets described above, such as the one described above in combination with the negative electrode assembly sheets 212 and 212' in any embodiment, which includes a version that includes the lithium metal layer 416A described above in combination with the negative electrode assembly sheets 212 and 212'. Figures 3A to 3C One or more functional coatings for the lithium metal layer 416A are combined. In this embodiment, each negative electrode assembly sheet 416S also includes a collector layer 416C. Each positive electrode sheet 420S can be combined with Figure 2A The positive electrode sheet 208 is the same or similar. Figure 4The direct stacking of the core 404 can be used Figure 2A Each negative electrode assembly sheet 416S can be made using any suitable pressure lamination process, such as that described above with reference to Figure 2C If one or more functional coatings (not shown) are provided for lithium metal layer 416A, the coatings may be applied to the respective separator layers 416B(1) and 416B(2) in any suitable manner, such as described above with reference to Figure 3B Combined application process. It should be noted that the number (4) of each negative electrode assembly sheet 416S and the number (5) of positive electrode sheets 420S shown are for convenience only. More or less of each of the negative electrode assembly sheet 416S and the positive electrode sheet 420S may be provided to suit a particular design.

[0092] Still reference Figure 4 , the lithium metal battery 400 also includes a positive terminal 424, which is electrically connected to each positive electrode 420 via a corresponding electrode 428 (1) to 428 (5). Similarly, the lithium metal battery also includes a negative terminal 432, which is electrically connected to each negative electrode 416 via a corresponding electrode 436 (1) to 436 (4), and is electrically connected to the collector layer 416C.

[0093] The above is a detailed description of an illustrative embodiment of the present invention. It should be noted that in this specification and the appended claims, conjunctions used in phrases such as "at least one of X, Y and Z" and "one or more of X, Y and Z", unless otherwise specified or indicated, will indicate that each item in the connected list can exist in any quantity in addition to all other items in the list, or in any quantity connected to all other items in the connected list, and each of all other items in the connected list may also exist in any quantity. Applying this general rule, in the embodiment where the aforementioned connected list consists of X, Y and Z, the conjunction phrase should include: one or more X; one or more Y; one or more Z; one or more X and one or more Y; one or more Y and one or more Z; one or more X and one or more Z; one or more X, one or more Y and one or more Z.

[0094] Without departing from the spirit and scope of the present invention, various modifications and additions may be made. The features of each of the various embodiments described above may be appropriately combined with the features of other described embodiments so as to provide a variety of feature combinations in associated new embodiments. In addition, although a plurality of separate embodiments have been described above, what is described herein is merely an illustration of the application of the principles of the present invention. In addition, although the specific methods herein may be shown and / or described as being performed in a particular order, within the ordinary skill of implementing aspects of the present disclosure, the order is highly variable. Therefore, this description is meant to be exemplary only and does not otherwise limit the scope of the present invention.

[0095] Exemplary embodiments have been disclosed above and shown in the accompanying drawings. It will be appreciated by those skilled in the art that various changes, omissions and additions may be made to the specific disclosure herein without departing from the spirit and scope of the present invention.

Claims

1. A method for manufacturing a lithium metal battery, the method comprising: Assembling the stacked winding cores, the assembling of the stacked winding cores comprising: Providing a plurality of negative electrode assembly sheets, each of the negative electrode assembly sheets comprising a lithium metal negative electrode laminated between a first separator and a second separator under pressure; in: The lithium metal negative electrode includes lithium metal having a melting temperature and exhibiting natural softness at a temperature below the melting temperature; and The first separator and the second separator are respectively pressure-laminated onto the lithium metal of the lithium metal negative electrode at a temperature lower than the melting temperature of the lithium metal, so that the first separator and the second separator are directly adhered to the lithium metal by the natural softness without using an adhesive; providing a plurality of positive electrode sheets; and The negative electrode assembly sheets and the plurality of positive electrode sheets are alternately stacked on each other to form the stacked jelly roll.

2. The method according to claim 1, further comprising forming the negative electrode assembly sheet, wherein: The forming includes: forming a laminated web including the first separator, the lithium metal layer, and the second separator, wherein forming the laminated web includes bringing the first separator and the second separator into direct contact with the lithium metal of the lithium metal negative electrode to form a multilayer structure, and applying pressure to the multilayer structure to form the laminated web; and The laminated web is cut to form the negative electrode assembly sheets.

3. The method according to claim 2, wherein: Applying pressure to the multilayer structure includes applying pressure only at a temperature of 60°C or below.

4. The method according to claim 3, wherein: Applying pressure to the multilayer structure includes conveying the multilayer structure through a nip roller, the nip roller applying a pressure in a range of 175 N / cm to 1750 N / cm.

5. The method according to claim 1, wherein: The first separator includes a functional coating layer for the lithium metal of the lithium metal negative electrode, and the functional coating layer is in direct contact with the lithium metal layer.

6. The method according to claim 5, wherein: The functional coating includes a ceramic material.

7. The method according to claim 5, wherein: The functional coating includes lithium fluoride.

8. The method according to claim 5, wherein: The functional coating includes lithium carbonate.

9. The method according to claim 1, further comprising forming the negative electrode assembly sheet, wherein the forming comprises: forming a laminated web comprising the first separator, the lithium metal layer, and the second separator, wherein the first separator comprises a functional coating in direct contact with the lithium metal of the lithium metal negative electrode without any adhesive between the functional coating and the lithium metal; and The laminated web is cut to form the negative electrode assembly sheets.

10. The method according to claim 9, wherein: Forming the laminated web includes contacting the first separator and the second separator with the lithium metal to form a multilayer structure, and applying pressure to the multilayer structure to form the laminated web.

11. The method of claim 10, further comprising applying the functional coating to a porous separator body to form the first separator.

12. The method according to claim 11, wherein: The functional coating includes a ceramic material.

13. The method according to claim 11, wherein: The functional coating includes lithium fluoride.

14. The method according to claim 11, wherein: The functional coating includes lithium carbonate.

15. The method according to claim 10, wherein: Applying pressure to the multilayer structure includes conveying the multilayer structure through nip rollers.

16. The method of claim 1, further comprising placing the stacked cores inside a housing.

17. The method of claim 16, further comprising adding an electrolyte to the interior of the housing and sealing the housing.

18. The method according to claim 1, wherein: The portion of the lithium metal directly adhered to the first separator has a thickness of less than 20 micrometers.

19. The method according to claim 18, wherein: The portion of the lithium metal of the lithium metal negative electrode has a thickness of less than 10 microns.

20. The method according to claim 1, wherein: A current collector layer is embedded in the lithium metal such that the lithium metal exists on both sides of the current collector layer.

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