Not Applicable
A portion of the material in this patent document is subject to copyright protection under the copyright laws of the United States and of other countries. The owner of the copyright rights has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the United States Patent and Trademark Office publicly available file or records, but otherwise reserves all copyright rights whatsoever. The copyright owner does not hereby waive any of its rights to have this patent document maintained in secrecy, including without limitation its rights pursuant to 37 C.F.R. § 1.14.
The technology of this disclosure pertains generally to batteries and methods of fabrication, and more particularly to lithium ion batteries and their packaging.
Advanced packaging technologies play an essential role in achieving high energy density batteries. This is especially important in microbatteries where >50% of the total mass can be comprised of packaging material and sealant that forms the hermetic seals, which in turn reduces the energy density. Microbatteries are typically formed through processes traditionally used in the semiconductor industry. As one example, active material may be sputtered onto a rigid substrate that is approximately 1 mm thick, and the battery layers are built up from there. Finally, another material (typically a polymer or another rigid substrate like a silicon wafer) is placed over the formed stack and sealed onto the aforementioned thick substrate. In this arrangement, the thick substrate, the polymer top sealing layer or second rigid substrate, and the adhesive form the “packaging”. Furthermore, tabs or through-holes need to be run outside the packaging to make an electrical connection. All these steps together represent the shortcomings of the current microbattery sealing process, which result in higher cost, and lower energy.
This disclosure generally describes a battery, and more particularly a “self-packaged” battery having current collectors that are sealed at their borders to encapsulate the active material without the need to use separate packaging.
This technology addresses the drawbacks of current microbattery packaging methods by using the current collectors as the packaging material, which obviates the need for additional packaging material to hermetically seal the microbattery. In addition to this, tabs are also eliminated because an electrical connection can be made directly to the current collectors, which eliminates potential regions that could fail and leak. The energy density is also increased by not using tabs because the tabs are inactive components that add mass and volume. Therefore, the manufacturing speed is significantly increased and the cost is reduced as a result of removing the traditional packaging step. This sealing technology is not limited to microbatteries, but can be applied to both very large cells (100's of Ah's) and very small cells (μAh). Taken together, this new technology increases the robustness and safety of the cell, increases the energy, and decreases cost.
In one embodiment, a battery according to the presented technology comprises a cathode current collector, an anode current collector, and an active material deposited on at least one of the current collectors, wherein the current collectors have borders sealed by an adhesive, and wherein the electrode stack (positive electrode, separator, electrolyte, and negative electrode) active material is encapsulated between the current collectors. This packaging approach is differentiated from current commercial sealing that uses either laminate pouch material or a cylindrical/prismatic metal “can” to hermetically encase the battery stack (anode, cathode, electrolyte and separator) because the sealing material is engineered to be electrically isolated from the cell stack. The technology described herein leverages the packaging being electronically connected to the cell stack, which enables a direct electrical connection right to the packaging.
In another embodiment, a “self-packaged” battery according to the presented technology comprises (a) a cathode current collector with a sealing border; (b) a cathode active material; (c) a separator; (d) an adhesive seal, (e) an anode active material; (f) an anode current collector with a sealing border; and (g) an electrolyte; (h) wherein the current collectors provide packaging for the active materials without requiring separate packaging.
In another embodiment, a “self-packaged” battery according to the presented technology comprises (a) a cathode current collector with a sealing border; (b) a cathode active material; (c) separator; (d) an adhesive seal; (e) an anode current collector with a sealing border; and (f) an electrolyte; (g) wherein the current collectors provide packaging for the active materials without requiring separate packaging.
In a still further embodiment, a “self-packaged” battery according to the presented technology comprises (a) a cathode current collector with a sealing border; (b) a cathode active material; (c) a separator; (d) an adhesive seal; (e) a porous or nonporous spacer; (f) an anode current collector; and (g) an electrolyte; (h) wherein the current collectors provide packaging for the active materials without requiring separate packaging.
In any of the foregoing embodiments, the electrolyte may be a liquid and the separator may be porous such that the liquid electrolyte flows into pores in the separator.
It will be appreciated that this technology addresses the drawbacks of current microbattery packaging methods by using the current collectors as the packaging material, which obviates the need for additional packaging material to hermetically seal the microbattery. In addition to this, tabs are also eliminated because an electrical connection can be made directly to the current collectors, which eliminates potential regions that could fail and leak. The energy density is also increased by not using tabs because the tabs are inactive components that add mass and volume. Therefore, the manufacturing speed is significantly increased and the cost is reduced as a result of removing the traditional packaging step. Taken together, this new technology, increases the robustness and safety of the cell, increases the energy, and decreases cost.
In any of the foregoing embodiments, a solid-state electrolyte may be used for the separator and conductive media and, therefore, a liquid electrolyte is not required.
Further aspects of the technology described herein will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the technology without placing limitations thereon.
The technology described herein will be more fully understood by reference to the following drawings which are for illustrative purposes only:
In general terms the presented technology is a cell or battery construct that does not require separate packaging for containing the active materials. More specifically, in the battery technology presented herein, the current carriers also act as encapsulation layers for the active materials. The active material is coated (through slurry casting, electrodeposition or other method) on one or more of the current carriers inside a bare border area that is either patterned or formed by etching away active material. The bare borders are used for sealing the perimeters of the current carriers together such that the active material stack (anode, cathode, electrolyte and separator) is encapsulated within the current carriers.
Refer now to
In any of the embodiments, the electrolyte may be a liquid and the separator may be porous such that the liquid electrolyte flows into pores in the separator.
In any of the embodiments, a solid-state electrolyte may be used for the separator and a liquid electrolyte is not required.
In any of the embodiments, the electrolyte may be a polymer electrolyte.
In various embodiments, the sealing border may be a bare border formed using laser ablation, electrodeposition, or masked slurry coating.
In various embodiments, the sealing border may have a width preferably ranging from about 10 μm to about 1000 μm, more preferably ranging from about 1 mm to about 10 mm, and more preferably about 1 mm. Narrower sealing borders provide higher energy density whereas wider sealing borders provide a more stable seal.
In one embodiment, the active material may be located inside the bare border.
In various embodiments, the cathode current collector may be a material selected from the group consisting of aluminum foil, aluminum, aluminum alloys, stainless steel, stainless steel alloys, gold, platinum, titanium, titanium alloys, and carbon. Other materials may be used as well.
In various embodiments, the cathode current collector may have a thickness preferably ranging from about 2 μm to about 500 μm, and more preferably about 23 μm.
In one embodiment, the cathode current collector is nonporous.
In various embodiments, the anode current collector may be a material selected from the group consisting of nickel, nickel alloys, copper, copper alloys, stainless steel, stainless steel alloys, gold, platinum, titanium, titanium alloys, and carbon. Other materials may be used as well.
In various embodiments, the anode current collector preferably has a thickness ranging from about 2 μm to about 500 μm, and more preferably about 9 μm.
In one embodiment, the anode current collector is nonporous.
In various embodiments, the cathode active material may comprise a material selected from the group consisting of Xerion's DirectPlate™ LCO, NMC, NCA, LMO, LFP, LiMn1.5Ni0.5O4, LiMn2O3, LCO, LiCFx and combinations thereof. Other active materials may be used as well.
In various embodiments, the cathode active material may comprise a commercial slurry selected from the group consisting of sulfur, LCO, LiMn2O4, LiFePO4, and LiNiMnCoO2 and combinations thereof. Other active materials may be used as well.
In various embodiments, the cathode active material may have a thickness ranging from about 1 μm to about 1000 μm, and preferably ranging from about 80 μm to about 120 μm.
In various embodiments, the anode active material may comprise a material selected from the group consisting of electroplated lithium, lithium alloys, magnesium, magnesium alloys, silicon, silicon alloys, germanium, germanium alloys, tin, tin alloys and combinations thereof. Other active materials may be used as well.
In various embodiments, the anode active material may comprise a commercial slurry selected from the group consisting of commercial slurries of LTO, lithium, graphite, silicon, tin, carbon nanotubes, carbon nanofibers, Ge, and graphene and combinations thereof. Other active materials may be used as well.
In various embodiments, the anode active material may have a thickness preferably ranging from about 1 μm to about 1000 μm, and more preferably ranging from about 20 μm to about 80 μm.
In various embodiments, the cathode active material may be applied to the cathode current collector using a technique such as slurry coating or electrodeposition.
In various embodiments, the adhesive material may comprise a material selected from the group consisting of Canvera 1110 P.O.D., polyolefins, epoxies (thermally or UV-curable), Cyanoacrylate (superglue), enhanced sulphurize polymer resin (MTI tape), solventless epoxy (Hardman) (thermally or UV-curable), and Diphenylmethane diisocyanate (Gorilla glue) or combinations thereof. Other adhesive materials may be used for sealing the borders as well.
In various embodiments, the adhesive seal may be applied to the perimeter as a viscous fluid by hand or machine, or more preferably through printing.
In one embodiment, lithium may be used from the cathode alone, which decreases both the cost and the cell thickness thereby increasing the energy density. During the first charge lithium is plated on the bare anode current collector and during discharge this lithium is then intercalated into the cathode. This design has been tested at Xerion, and the first cycle Coulombic efficiency is about 90%, and without polarization at C/10 (10 hour charge or discharge).
In one embodiment, the separator may have a thickness of about 20 μm.
Examples of suitable separator materials include, but are not limited to, Celgard®2340, 2325, C500, C480, 2320, C300, C250, C200, C212, M825, M824, 2400, 2500, A273, 3400/3401, 3500/3501, 4550, 4560, 5550, etc., trilayer separators, monolayer separators, coated separators, and the like.
In various embodiments, liquid electrolyte may be a material selected from the group consisting of LiPF6, LiBOB, LiFOB, LiBF4, LiClO4, LiCl, LiBr and LiTFSI dissolved in a carbonate blend (EC, DEC, DMC, EMC, PC, and combinations thereof). Other materials may be used as well.
In various embodiments, the battery size, described by the length of one edge, may range from about 1 μm to about 1 mm, about 1 mm to about 10 mm, about 10 mm to about 100 mm, and about 10 cm to about 1000 cm, but can have other sizes and form factors as well (e.g., the form factor is not limited to square).
In various embodiments, the battery capacity may range from about 1 μAh to about 40 Ah. Other capacities may be used too.
In various embodiments, a battery according the presented technology can be fabricated according to the following steps or a modification thereof depending on the whether there is active material on the anode current collector or whether the spacer is used. The first step would be to coat electrode (active) material onto the substrate being used for the current collector (e.g., electroplate, or slurry cast). A next step would be to remove active material from the perimeter of the current collector to create the sealing border, by for example, laser etching. Next, the electrodes and separator are assembled and sealant is applied to the sealing borders to form a robust seal around the entire perimeter except for a small region for electrolyte filling. The assembly is then filled with electrolyte and the filling region sealed off (if a liquid electrolyte is used instead of a solid-state electrolyte separator), and the device is complete and ready for use.
The graph 600 in
Positioned below the battery 400 in
A. Canvera Preparation (this material is used on the bare edges to form a seal). Note: The resultant solution is referred to as POD solution or POD coating (PolyOlefin Dispersion).
Materials:
Table 1 sets forth materials used.
Procedure:
1. Prepare in advance approximately 250 mL of a solution of 0.3% by weight DMEA in DI water. Mix under medium stirring for 10 minutes or until thoroughly mixed. Cap and set aside. This solution is referred to as basic water.
2. Prepare in advance a 30% by weight solution of primid QM-1260 in basic water. Prepare 25-50 mL total; this is not used in large quantity. Add Primid QM-1260 slowly under moderate stirring; this takes a while to dissolve completely, but it will dissolve (30 min-1 hour). Cap and set aside. This solution is referred to as Primid solution. When not in use, cap and store in 4° C. refrigerator.
3. Measure out 44.57 g Canvera POD, 40.36 g basic water, 6.73 g 1-butanol, 6.73 g 2-butoxyethanol and 1.6 g Primid solution. Add each ingredient to a sealable, glass container under moderate stirring, in the order listed in the proceeding sentence. Cap container and continue stirring until solution is well mixed. It is important to stir the solution whenever possible to ensure everything remains well mixed for coating.
4. The prepared solution can be stored in a 4° C. refrigerator for approximately two weeks, allowing solution to come up to room temp under gentle stirring before using. Past two weeks, it is suspected based on testing that the volatile solvents react or evaporate, and end up causing bubbling in the final cured product. It is best to prepare the solution immediately before use if possible. It is also important to maintain a basic (9.5-11) pH to prevent premature crosslinking.
B. Application on to the Bare Edges:
According to the manufacturer, the intended mode of application of the POD solution is through an industrial sprayer. The goal is to apply an even coating that will dry to be 6-12 μm thick. In practice, this was achieved with a micropipette for better control. The material was deposited on bare foil surrounding the active material on patterned electrodes, being careful to leave a small gap (˜0.1-0.2 mm) between the material and the active material. The POD solution will wet the metal and spread slightly. Any excess was removed by wicking from the edge of the foils with a piece of clean aluminum foil until an even coating was achieved. It was important to carry this step out quickly to prevent the coating from curing prematurely in air. POD solution that dries in air will not cure correctly, and will likely crack or suffer poor adhesion. It also takes on a white color when improperly dried before curing. If the coat is too thick, it can bubble up and ruin the coat. Alternatives would be spray depositing the POD solution from a pneumatic sprayer.
C. Curing:
Curing is performed in a gravity convection oven set to 173° C. Samples are placed carefully on alumina spacers (in this example porous spacers are used) to avoid the samples curing to the metal racks. Binder for active materials typically melts around 176-178° C. according to MTI, which is part of the reason 173° C. was chosen as a curing temp. As soon as the samples are loaded, close the door and start a timer. The oven typically dropped 10-15° C. from the loading process. Samples were left to cure for 3-3.5 min, depending on how low the temp got after loading. By 2-3 min into the curing the oven should have recovered to −170° C. The datasheet for the POD recommends a minimum cure of 170° C. for 1.5 min. Typically, by 3.5 min the temperature had recovered to 173° C., and the samples were removed and let cool in air. Copper foils seemed to cure faster (30-45 seconds less time), possibly due to their heat transfer coefficient and their being thinner than the aluminum. The coating did not appear to suffer extra time in the cure, but what was risked was the overshoot of the oven PID causing loss of adhesion of the active materials after being removed, which did happen repeatedly at 5 minutes cure time. When properly cured, the coating should appear translucent and semi-gloss.
D. Post Curing:
No post curing was recommended. Before exposing the coating to electrolyte, it is recommended the coatings undergo heated vacuum drying at 65° C. for 6-8 hours to drive off any remaining solvents or moisture, same as is recommended for porous active materials.
E. Electrolyte Interaction:
Samples were submerged in 1M LiPF6 (EC:DMC) electrolyte for 2 months. During that time, the weight loss and gain were within error of the scale (˜1.3% fluctuation). At each week for the first 4 weeks, the sample was removed, dried with kimwipes and tested for conductivity (Open circuit test) with a DMM. After 2.5 months, the coating remained visually unchanged, and no shorting was detectable through the coating with low current testing.
F. T-Peel Testing:
Samples were prepared using battery grade 20 μm aluminum foil. A single or double coat of POD solution was cast using the pipette technique described in Application. Testing samples were cut from the prepared samples after measuring the thickness and checking for consistency. Samples were cured using an impulse sealer for variable amounts of time, then set up in a homemade linear rail force measuring device. Samples were carefully clamped in aluminum screw clamps at 180° under no tension. The force gauge was zeroed, then the motor activated to pull the sample apart at a constant, slow rate. Peak force was measured at the fixed end using a DFS-50N Nextech digital force gauge. After the samples had been fully peeled apart, the final reading was recorded. Satisfactory T-peel test results were observed.
From the description herein, it will be appreciated that that the present disclosure encompasses multiple embodiments which include, but are not limited to, the following:
1. A self-packaged battery comprising current collectors and active material between the current collectors, wherein the current collectors have sealed borders that encapsulate the active material, and wherein the current collectors provide packaging for the active material without requiring separate packaging.
2. A self-packaged battery comprising: (a) a cathode current collector; (b) an anode current collector; and (c) an active material deposited on at least one of the current collectors; (d) wherein the current collectors have borders sealed by an adhesive material; and (e) wherein the active material is encapsulated between the current collectors and the current collectors provide packaging for the active materials without requiring separate packaging.
3. A self-packaged battery comprising: (a) a cathode current collector with a sealing border; (b) a cathode active material; (c) a separator; (d) an anode active material; (e) an anode current collector with a sealing border; (f) an electrolyte; and (g) an adhesive material that seals the sealing borders; (h) wherein the current collectors provide packaging for the active materials without requiring separate packaging.
4. A self-packaged battery comprising: (a) a cathode current collector with a sealing border; (b) a cathode active material; (c) a separator; (d) an anode current collector with a sealing border; (e) an electrolyte; and (f) an adhesive material that seals the sealing border; (g) wherein the current collectors provide packaging for the active materials without requiring separate packaging.
5. A self-packaged battery comprising: (a) a cathode current collector with a sealing border; (b) a cathode active material; (c) a separator; (d) a porous or nonporous spacer; (e) an anode current collector with a sealing border; (f) an electrolyte; and (g) an adhesive material that seals the sealing border; (h) wherein the current collectors provide packaging for the active materials without requiring separate packaging.
6. A method of fabricating a self-packaged battery, comprising providing the current collectors and active material of any preceding embodiment and sealing the borders of the current collectors to encapsulate the active material, wherein the current collectors provide packaging for the active material without requiring separate packaging.
7. A method of fabricating a self-packaged battery, comprising providing current collectors having borders, placing an active material between the current collectors, and sealing the borders of the current collectors to encapsulate the active material, wherein the current collectors provide packaging for the active material without requiring separate packaging.
8. The battery or method of any preceding embodiment, wherein the electrolyte comprises a liquid that flows into pores in the separator.
9. The battery or method of any preceding embodiment, wherein the separator and electrolyte comprise a solid-state electrolyte.
10. The battery or method of any preceding embodiment, wherein the electrolyte comprises a polymer electrolyte.
11. The battery or method of any preceding embodiment, wherein the sealing border comprises a bare border formed using laser ablation, electrodeposition, or masked slurry coating.
12. The battery or method of any preceding embodiment, wherein the sealing border has a width preferably ranging from about 10 μm to about 1000 μm, more preferably ranging from about 1 mm to about 10 mm, and more preferably about 1 mm.
13. The battery or method of any preceding embodiment, wherein narrower sealing borders provide higher density and wherein wider sealing borders provide a more robust seal.
14. The battery or method of any preceding embodiment, wherein the active electrode material is located inside the bare border.
15. The battery or method of any preceding embodiment, wherein the cathode current collector comprises a material selected from the group consisting of aluminum foil, aluminum, aluminum alloys, nickel, nickel alloys, copper, copper alloys, stainless steel, stainless steel alloys, gold, platinum, titanium, titanium alloys, and carbon.
16. The battery or method of any preceding embodiment, wherein the cathode current collector has a thickness preferably ranging from about 2 μm to about 500 μm, and more preferably about 23 μm.
17. The battery or method of any preceding embodiment, wherein the cathode current collector is nonporous.
18. The battery or method of any preceding embodiment, wherein the anode current collector comprises a material selected from the group consisting of aluminum foil, aluminum, aluminum alloys, nickel, nickel alloys, copper, copper alloys, stainless steel, stainless steel alloys, gold, platinum, titanium, titanium alloys, and carbon.
19. The battery or method of any preceding embodiment, wherein the anode current collector preferably has a thickness ranging from about 2 μm to about 500 μm, and more preferably about 9 μm.
20. The battery or method of any preceding embodiment, wherein the anode current collector is nonporous.
21. The battery or method of any preceding embodiment, wherein the cathode active material comprises a material selected from the group consisting of DirectPlate LCO, NMC, NCA, LMO, LFP, LiMn1.5Ni0.5O4, LiMn2O3, LCO, LiCFx and combinations thereof. Other active materials may be used as well.
22. The battery or method of any preceding embodiment, wherein the cathode active material comprises a slurry selected from the group consisting of sulfur, LCO, LiMn2O4, LiFePO4, and LiNiMnCoO2.
23. The battery or method of any preceding embodiment, wherein the cathode active material has a thickness ranging from about 1 μm to about 1000 μm, and preferably ranging from about 80 μm to about 120 μm.
24. The battery or method of any preceding embodiment, wherein the anode active material comprises a material selected from the group consisting of DirectPlate LCO, NMC, NCA, LMO, LFP, LiMn1.5Ni0.5O4, LiMn2O3, LCO, LiCFx and combinations thereof.
25. The battery or method of any preceding embodiment, wherein the anode active material comprises a slurry selected from the group consisting of LTO, lithium, graphite, silicon, tin, carbon nanotubes, carbon nanofibers, Ge, and graphene and combinations thereof. Other active materials may be used as well.
26. The battery or method of any preceding embodiment, wherein the anode active material has a thickness preferably ranging from about 1 μm to about 1000 μm, and more preferably ranging from about 80 μm to about 120 μm.
27. The battery or method of any preceding embodiment, wherein the cathode active material is applied to the cathode current collector using a technique such as slurry coating or electrodeposition.
28. The battery or method of any preceding embodiment, wherein the current collectors have borders sealed by an adhesive material selected from the group consisting of Canvera 1110 P.O.D., polyolefins, polyimides, epoxies (thermally or UV-curable), Cyanoacrylate (superglue), enhanced sulphurize polymer resin (MTI tape), solventless epoxy (hardman) (thermally or UV-curable), and Diphenylmethane diisocyanate (gorilla glue) or combinations thereof.
29. The battery or method of any preceding embodiment, wherein the adhesive material is applied to the borders by hand, by machine, or through printing.
30. The battery or method of any preceding embodiment, wherein lithium is used from the cathode alone and plated on the bare anode current collector during charging.
31. The battery or method of any preceding embodiment, wherein the separator has a thickness of about 20 μm.
32. The battery or method of any preceding embodiment, wherein the separator comprises a material with pores that hold the electrolyte.
33. The battery or method of any preceding embodiment, wherein the liquid electrolyte comprises a material selected from the group consisting of LiPF6 dissolved in a carbonate blend (EC, DEC, DMC, EMC, PC, and combinations thereof).
34. The battery or method of any preceding embodiment, wherein the battery size, described by the length of one edge, may range from about 1 μm to about 1 mm, about 1 mm to about 10 mm, about 10 mm to about 100 mm, and about 10 cm to about 1000 cm, but can have other sizes and form factors as well (e.g., the form factor is not limited to square).
35. The battery or method of any preceding embodiment, wherein the battery capacity ranges from about 1 μAh to about 40 Ah.
36. The battery of any of preceding embodiment, wherein the current collectors have borders formed by laser ablation.
37. The battery or method of any preceding embodiment, wherein the adhesive material is applied to the borders by hand, by machine, or through printing.
38. The battery or method of any preceding embodiment, wherein the borders are hermetically sealed by the adhesive material.
39. The battery or method of any preceding embodiment, wherein the battery is fabricated with current collectors that are sealed at their borders to encapsulate the active material and dispense with the need to use separate packaging.
40. The battery or method of any preceding embodiment, wherein the borders have widths ranging from about 1 μm to about 10 mm.
As used herein, the singular terms “a,” “an,” and “the” may include plural referents unless the context clearly dictates otherwise. Reference to an object in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.”
Phrasing constructs, such as “A, B and/or C”, within the present disclosure describe where either A, B, or C can be present, or any combination of items A, B and C. Phrasing constructs indicating, such as “at least one of” followed by listing group of elements, indicates that at least one of these group elements is present, which includes any possible combination of these listed elements as applicable.
References in this specification referring to “an embodiment”, “at least one embodiment” or similar embodiment wording indicates that a particular feature, structure, or characteristic described in connection with a described embodiment is included in at least one embodiment of the present disclosure. Thus, these various embodiment phrases are not necessarily all referring to the same embodiment, or to a specific embodiment which differs from all the other embodiments being described. The embodiment phrasing should be construed to mean that the particular features, structures, or characteristics of a given embodiment may be combined in any suitable manner in one or more embodiments of the disclosed apparatus, system or method.
As used herein, the term “set” refers to a collection of one or more objects. Thus, for example, a set of objects can include a single object or multiple objects.
As used herein, the terms “approximately”, “approximate”, “substantially” and “about” are used to describe and account for small variations. When used in conjunction with an event or circumstance, the terms can refer to instances in which the event or circumstance occurs precisely as well as instances in which the event or circumstance occurs to a close approximation. When used in conjunction with a numerical value, the terms can refer to a range of variation of less than or equal to ±10% of that numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. For example, “substantially” aligned can refer to a range of angular variation of less than or equal to ±10°, such as less than or equal to ±5°, less than or equal to ±4°, less than or equal to ±3°, less than or equal to ±2°, less than or equal to ±1°, less than or equal to ±0.5°, less than or equal to ±0.1°, or less than or equal to ±0.05°.
Additionally, amounts, ratios, and other numerical values may sometimes be presented herein in a range format. It is to be understood that such range format is used for convenience and brevity and should be understood flexibly to include numerical values explicitly specified as limits of a range, but also to include all individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly specified. For example, a ratio in the range of about 1 to about 200 should be understood to include the explicitly recited limits of about 1 and about 200, but also to include individual ratios such as about 2, about 3, and about 4, and sub-ranges such as about 10 to about 50, about 20 to about 100, and so forth.
Although the description herein contains many details, these should not be construed as limiting the scope of the disclosure but as merely providing illustrations of some of the presently preferred embodiments. Therefore, it will be appreciated that the scope of the disclosure fully encompasses other embodiments which may become obvious to those skilled in the art.
All structural and functional equivalents to the elements of the disclosed embodiments that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed as a “means plus function” element unless the element is expressly recited using the phrase “means for”. No claim element herein is to be construed as a “step plus function” element unless the element is expressly recited using the phrase “step for”.
This application claims priority to, and the benefit of, U.S. provisional patent application Ser. No. 62/940,102 filed on Nov. 25, 2019, incorporated herein by reference in its entirety.
Number | Date | Country | |
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62940102 | Nov 2019 | US |