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1. WO2020117346 - BATTERY PARTS HAVING SOLVENTLESS ACID BARRIERS AND ASSOCIATED SYSTEMS AND METHODS

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

BATTERY PARTS HAVING SOLVENTLESS ACID BARRIERS AND

ASSOCIATED SYSTEMS AND METHODS

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Patent Application No. 62/776,977, titled "BATTERY PARTS HAVING SOLVENTLESS ACID BARRIERS AND ASSOCIATED SYSTEMS AND METHODS," and filed December 7, 2018, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The following disclosure relates generally to battery parts and, more particularly, to battery terminals, battery terminal bushings, and the like having solventless acid barriers.

BACKGROUND

[0003] Battery terminals are typically cold formed or die cast from lead or lead alloys. In a conventional battery, the terminals protrude from a casing or container which carries an electrolyte, such as sulfuric acid. The container is typically formed from a moldable thermoplastic resin, such as polypropylene. During manufacture of the container, the resin flows around the base of the terminals so that the resin will secure the terminals in place once it hardens. After a terminal has been secured, a lead anode can be inserted into a central hole in the terminal and melted to fill the hole and form a mechanical and electrical connection to a battery grid positioned within the container.

[0004] The different coefficients of thermal expansion between the battery container and the lead terminals can cause these materials to separate at their interface as a result of thermal cycling. The battery terminals may also become loose in the container wall if subjected to repeated or excessive twisting or torsional loads. These factors can cause small cracks to form between the terminals and the container wall, and electrolyte can readily pass through these cracks due to the low surface tension of electrolytes. Accordingly, it can be important to establish a good seal between the lead terminals and the container to avoid migration of the electrolyte (e.g., sulfuric acid) out of the battery container and/or ingress of gases (e.g., oxygen) into the battery container. [0005] Typically, a sealant such as polyisobutylene is provided between the lead terminals and the battery container to seal the interface therebetween. However, conventional sealants must be dissolved in a solvent (to form, e.g., a solution including polyisobutylene) before being applied to the battery terminals. The commercial solvents that are capable of dissolving such sealants include hydrocarbon-based or chlorinated solvents. Such solvents, however, are intrinsically toxic, extremely flammable, air pollutants, and/or volatile organic compounds. For example, trichloroethylene (TCE) is commonly used to dissolve sealants including polyisobutylene, yet TCE is classified as a hazardous air pollutant (HAP) compound in the United States, and the use of TCE is severely restricted and being phased out in the European Union and China.

[0006] As disclosed in U.S. Patent No. 5,709,967, D-limonene— a naturally occurring product extracted from citrus fruit peels— has been proposed as a substitute for TCE. (U.S. Patent No. 5,709,967 is incorporated herein by reference in its entirety.) However, the flammability and slow evaporation of D-limonene has greatly limited its commercial applicability.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Many aspects of the present technology can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on clearly illustrating the principles of the present technology.

[0008] Figure 1 is a side view of a battery part at least partially coated with a sealant configured in accordance with an embodiment of the present technology.

[0009] Figure 2 is a side view of a battery assembly including the battery part of Figure 1 configured in accordance with an embodiment of the present technology.

[0010] Figure 3 is a partially schematic top-view of a battery part sealant application system configured in accordance with an embodiment of the present technology.

DETAILED DESCRIPTION

[0011] The following disclosure describes various embodiments of battery parts, such as battery terminals, bushings, and the like that are at least partially coated with sealant, and associated assemblies and methods of manufacture and use. In some embodiments, a battery part configured in accordance with the present disclosure includes a body having a base portion that is configured to be embedded in battery container material when the battery container is formed. The base portion can have a sealant applied to an external surface thereof. The sealant is configured to provide a seal or barrier between the battery container material and the battery part. As described in greater detail below, in some embodiments, the sealant is a non-toxic, light-curable resin. As discussed above, many existing sealants require the use of solvents that are hazardous to humans and/or the environment. In contrast, the battery parts of the present technology do not require the use of hazardous solvents while still effectively sealing the interface between the battery parts and the battery container material in which they are embedded.

[0012] Certain details are set forth in the following description and in Figures 1-3 to provide a thorough understanding of various embodiments of the disclosure. Other details describing well-known structures and systems often associated with battery parts (e.g., lead and/or lead alloy battery parts, moldable battery containers, etc.), and methods for forming such parts (e.g., forming, casting, injection molding, etc.), as well as other battery parts and assemblies, are not set forth in the following disclosure to avoid unnecessarily obscuring the description of the various embodiments of the present technology. Moreover, many of the details and features shown in the Figures are merely illustrative of particular embodiments of the present technology. Accordingly, other embodiments can have other details and features without departing from the spirit and scope of the present technology. In addition, the various elements and features illustrated in the Figures may not be drawn to scale. Furthermore, various embodiments of the present technology can include structures other than those illustrated in the Figures and are expressly not limited to the structures shown in the Figures.

[0013] Figure 1 is a side view of a battery part 100 configured in accordance with an embodiment of the present technology. In the illustrated embodiment, the battery part 100 comprises a battery terminal or terminal bushing. The battery part 100 can be formed from lead, lead alloy, and/or other suitable materials by forming (e.g., cold forming, cold-forming with a segmented mold, hot-forming, roll-forming, stamping, etc.), casting (e.g., die casting), forging, machining, and/or other suitable methods known in the art. In the illustrated embodiment, the battery part 100 includes a body having a projecting portion or lug portion 102 that extends from a base portion 104. The lug portion 104 can be any portion of the battery part 100 configured to be connected to an external electrical connector such as, for example, a post, a flange, a projection including one or more holes, etc. The battery part 100 can also include a passage or through-hole 105 extending through the battery part 100 from a first end portion 101 to a second end portion 103 of the battery part 100. In the illustrated embodiment, the battery part 100 is generally cylindrical and rotatably symmetric, and the through-hole 105 is aligned with a longitudinal axis L of the battery part 100. In other embodiments, the battery part 100 can have other (e.g., asymmetric) shapes.

[0014] In some embodiments, the battery part 100 can include a circumferential flange 106 at an approximate midpoint of the battery part 100 between the lug portion 102 and the base portion 104. In the illustrated embodiment, the flange 106 projects radially outward beyond the base portion 104 and extends circumferentially around the battery part 100. In some embodiments, the flange 106 can have a generally circular shape while, in other embodiments, the flange 106 can have a polygonal or other shape. In the illustrated embodiment, the flange 106 includes a plurality of recesses or grooves 107 extending at least partially through the flange 106. In some embodiments, the grooves 107 can have an upside down U-shaped configuration in which the grooves open in a direction away from the lug portion 102 and toward the base portion 104. In other embodiments, the grooves 107 can be omitted, or the flange 106 can have a different arrangement of grooves. For example, the flange 106 can include a different number of grooves and/or the grooves can open in a direction toward the lug portion 102. In some embodiments, the flange 106 is configured to engage or otherwise grip battery container material (shown in Figure 2) that is molded around the flange 106 to inhibit the battery part 100 from twisting or otherwise moving in the battery container.

[0015] an exterior surface (e.g., an outward-facing surface) (e.g., in a direction away from the through-hole 105), and a plurality of recessed portions or grooves 1 12 formed therebetween.

[0016] In the illustrated embodiment, the base portion 104 includes a plurality of circumferential acid rings or sealing portions 1 10 that extend generally radially outward/away from the longitudinal axis L of the battery part 100, and a plurality of recessed portions or grooves 1 12 formed therebetween. The battery part 100 can include more or fewer than two sealing portions 1 10 in other embodiments. In the illustrated embodiment, the sealing portions 1 10 have a generally rectangular cross-sectional shape. In other embodiments, the sealing portions 1 10 can have a generally round, circular, or other cross-sectional shape or profile, and/or the sealing portions 1 10 can have different shapes from one another. As described in detail below, a battery container (shown in Figure 2) can be formed around the sealing portions 1 10. The profile of the sealing portions 1 10 forms a labyrinth or tortuous path that inhibits fluids from leaking from the battery container between the battery part 100 and the container during formation and in use.

[0017] The battery part 100 is provided by way of example only, and as those of ordinary skill in the art will appreciate, in other embodiments, battery parts configured in accordance with the present disclosure can have other suitable configurations and shapes including, for example, more or fewer flanges (e.g., torque flanges) and/or more fewer sealing portions having other shapes, arrangements, etc. For example, the battery part 100 can include one or more features that are generally similar to the features of the battery parts disclosed in (i) U.S. Patent No. 9,190,654, titled "BATTERY PARTS AND ASSOCIATED SYSTEMS AND METHODS," filed March 25, 2014; (ii) U.S. Patent No. 9,935,306, titled "BATTERY PARTS HAVING RETAINING AND SEALING FEATURES AND ASSOCIATED METHODS OF MANUFACTURE AND USE," filed July 7, 2014; and/or (iii) U.S. Patent No. 9,748,551 , titled "BATTERY PARTS HAVING RETAINING AND SEALING FEATURES AND ASSOCIATED METHODS OF MANUFACTURE AND USE," filed June 29, 2012, each of which is incorporated herein by reference in its entirety.

[0018] In another aspect of the illustrated embodiment, the battery part 100 includes a coating or sealant 1 14 that is formed over at least a portion of an exterior surface (e.g., an outward-facing surface) of the base portion 104. In some embodiments, the sealant 1 14 has a generally uniform thickness of from about 1 mm to about 2 mm (e.g., from 1.5 mm to about 2 mm). In other embodiments, the sealant 1 14 can have a different or varying thickness. As described in detail below with reference to Figure 2, the sealant 1 14 is configured to provide a seal or barrier at the interface between the battery part 100 and battery container material to inhibit fluids and gases from moving into or out off the battery container between the battery part 100 and the container during formation and in use.

[0019] The sealant 1 14 can be a solventless compound that is resistant to corrosion by electrolytes (e.g., sulfuric acid) or other battery fluids. That is, the sealant 1 14 can be applied to the battery part 100 and cured without the use of (e.g., evaporation of) a solvent, such as trichloroethylene (TCE). In some embodiments, for example, the sealant 1 14 is a light-curable material such as a resin or organic compound. More particularly, the sealant 1 14 can be a light-curable resin that includes acrylated urethanes (e.g., a light-curable acrylated urethane resin). In some embodiments, the sealant 1 14 is curable via exposure to broad spectrum ultraviolet (UV) light, narrow spectrum UV light (e.g., LED light), visible light, and/or light having other suitable wavelengths. In certain embodiments, the sealant 1 14 can be a light-curable maskant or masking resin manufactured by Dymax Corporation, of Torrington, Connecticut, such as the light-curable maskants manufactured under the trademark "SpeedMask." In some embodiments, the sealant 1 14 (identified as "Cured Material" in the chemical equation below) can be formed and cured according to the following chemical equation:

9 9 9 9

C=C C*M,VWW,VC.C=C C=C -C-~ R~C - C=C + Photoinitiator
Cured Material

Ure!hane Acrylate Qligotnsr Acrylate Monotner

[0020] Notably, because the sealant 1 14 need not be dissolved in a solvent before application, the sealant 1 14 can be non-toxic, non-flammable, and can have no negative or environmental impacts.

[0021] Figure 2 is a partial cross-sectional view of a battery assembly 220 including the battery part 100 of Figure 1 attached to a battery casing or container 222 in accordance with an embodiment of the present technology. In the illustrated embodiment, the battery assembly 220 is attached to the battery container 222 so that the lug portion 102 is exposed and accessible. The battery container 222 and the sealant 1 14 of the battery part 100 are shown in cross-section in Figure 2 for the sake of clarity. The battery container 222 can be formed from a moldable material 224, such as polypropylene, polyethylene, other plastics, thermoplastic resins, and/or other suitable materials known in the art. During manufacture of the battery assembly 220,

the material 224 can be flowed in a molten form into a mold (not shown) supporting the base portion 104 of the battery part 100 so that the sealing portions 1 10 are embedded within the material 224. The shape of the sealing portions 1 10 form a labyrinth or tortuous path that prevents or at least inhibits fluids (e.g., electrolyte, acid, water, etc.) from escaping the battery container 222. In some embodiments, as shown in Figure 2, the material 224 can also be flowed around the flange 106 so that the flange 106 is at least partially embedded in the material 224. The battery assembly 220 can also include a lead anode or conductor 226 that is mechanically and electrically connected to the battery part 100. More specifically, the conductor 226 fills the through-hole 105 and can be connected to a battery grid (not shown) positioned within the battery container 222, as is known in the art.

[0022] Referring to Figures 1 and 2 together, the sealant 1 14 is configured to seal the interface between the battery container 222 and the battery part 100 to inhibit an electrolyte (e.g., sulfuric acid) from leaking from the battery container 222 and to inhibit the ingress of oxygen, or other gases into the battery container 222, which can diminish the capacity of the battery. In particular, the sealant 1 14 is configured to seal the interface even as the battery part 100 and the material 224 tend to pull away from each other, for example, as a result of the differing coefficients of thermal expansion of these components and thermal cycling during use of the battery assembly 220. In some embodiments, the sealant 1 14 is formed only over the exterior surfaces of the sealing portions 1 10 and the grooves 1 12. In other embodiments, the sealant 1 14 can be formed over all or a different portion of the base portion 104, the flange 106, and/or other portions of the battery part 100 that may interface with the material 224 of the battery container 222. For example, the sealant 1 14 can be formed over the entire exterior surface of the base portion 104 (e.g., over the second end portion 103, the sealing portions 1 10, and the grooves 1 12) and/or the flange 106 (e.g., including in the grooves 107). As shown, the sealant 1 14 need not be formed over the exterior surface of the lug portion 102 which projects from the battery container 222 and therefore does not interface with the container material 224.

[0023] The sealant 1 14 can be formed on or applied to the battery part 100 using a variety of suitable methods. For example, the sealant 1 14 can be sprayed or brushed onto the battery part 100, and/or the battery part 100 can be dipped and/or rolled in the sealant 1 14. Moreover, the sealant 1 14 can be applied in a single coat or in multiple coats (e.g., by dipping, rolling, spraying, and/or bushing the sealant 1 14 onto the battery part 100 multiple times). In some embodiments, the battery part 100 is rotated after or during application of the sealant 1 14 to achieve a desired (e.g., uniform) thickness of the coating of the sealant 1 14. Accordingly, the sealant 1 14 can be selected to have a desired viscosity to facilitate application via a chosen method (e.g., dipping, spraying, painting, etc.). After applying the sealant 1 14 to the battery part 100, the sealant 1 14 is cured by exposing the sealant 1 14 to light. As described above, the sealant 1 14 can be cured via exposure to narrow spectrum UV light, broad spectrum UV light, visible light, and/or light of other wavelengths. In some embodiments, the battery part 100 can be rotated relative to a suitable light source to cure the sealant 1 14 thereon. In other embodiments, the battery part 100 can be exposed to multiple light sources, or a light source can be moved relative to the battery part 100 to facilitate curing without rotation or other movement of the battery part 100. In some embodiments, the sealant 1 14 is configured to cure rapidly from exposure to light of a suitable wavelength. In some embodiments, for example, curing can take between about 1-60 seconds.

[0024] In some embodiments, because the sealant 1 14 is light-curable and can be applied without evaporating a hazardous solvent, the devices/systems for applying and curing the sealant 1 14 need not be positioned within a controlled air environment (e.g., within a ventilated enclosure). As such, the devices/systems for applying and curing the sealant 1 14 can be placed nearby to the devices/systems for manufacturing the battery part 100. Accordingly, the present technology can reduce the cost, complexity, and/or time required to manufacture a battery part as compared to, for example, conventional manufacturing techniques that utilize a solvent (e.g., trichloroethylene) to apply and cure a sealing compound.

[0025] Figure 3 is a partially schematic top-view of a battery part sealant application system 330 ("system 330") configured in accordance with an embodiment of the present technology. The system 330 can operate to apply and cure the sealant 1 14 on a plurality of the battery parts 100 (identified individually as battery parts 100a-100k). In the illustrated embodiment, the system 330 includes a rotatable support or platform 332 configured to receive a plurality of the battery parts 100 via a loading mechanism 334. The loading mechanism 334 can include a vibratory hopper and/or

accumulator/orientation loading station that is configured to receive unfished battery parts 100 and suitably orient/arrange the battery parts 100 for presentation and mounting on the rotatable platform 332. In other embodiments, the loading mechanism 334 can include a robotic arm or gripper for moving the battery parts 100 onto the rotatable platform 332. In other embodiments, the loading mechanism 334 can be omitted and the unfinished battery parts 100 can be manually loaded onto the rotatable platform 332.

[0026] The rotatable platform 332 can include a plurality of recesses and/or fixtures (not pictured) configured to releasably grasp and secure individual ones of the battery parts 100 so that the base portion 104 is exposed. In some embodiments, the fixtures can include spindles that are rotatable (e.g., as indicated by the arrow A) to individually rotate the corresponding ones of the battery parts 100. The rotatable platform 332 can be rotated or indexed (e.g., as indicated by the arrow B) to move the battery parts 100 sequentially through a sealant application station 336, a curing station 338, and to an output mechanism 340.

[0027] The sealant application station 336 includes a sealant applicator or dispenser 342 for coating (e.g., spraying) the sealant 1 14 on some or all of the base portion 104 of a corresponding one of the battery parts 100 (e.g., the battery part 100c in Figure 3) that is positioned at the sealant application station 336. In the illustrated embodiment, the sealant dispenser 342 is a pressurized sprayer having at least one spray nozzle 343 for directing the sealant 1 14 toward the battery part 100c that is positioned at the sealant application station 336. In some embodiments, the nozzle 343 is configured to remain stationary while the battery part 100c is rotated (e.g., on a corresponding spindle) at the sealant application station 336. In other embodiments, the sealant dispenser 342 is actuatable in at least one direction (e.g., in the X-,Y-, and Z-planes) such that the nozzle 343 is movable relative to the battery part 100 to suitably apply the sealant 1 14 to the battery part 100 without rotation or with minimal rotation of the battery part 100. For example, the sealant dispenser 342 can be electromechanically actuated to vary the position of the nozzle 343. In some embodiments, the motion of the nozzle 343 can be synchronized with the specific geometry of the battery part 100c and/or the rotation speed of the battery part 100c can be varied to provide a desired pattern and/or thickness of the coating of the sealant 1 14.

The system 330 can further include one or more additional sealant dispensers (e.g., a sealant dispenser 344 shown schematically in Figure 3) that are configured to coat the battery parts 100 with the sealant 1 14 (e.g., with another coat of the sealant 1 14) or a different material. Although the sealant dispenser 342 is depicted a pressured sprayer in Figure 3, the sealant dispenser can include any suitable structure for applying the sealant 1 14 to the battery parts 100. For example, the sealant dispenser 342 can include one or more brushes, a dipping station, etc.

[0028] A light source 346 is positioned at the curing station 338 and is configured to irradiate the battery parts 100 to cure the sealant 1 14 thereon. In some embodiments, the light source 346 includes one or more UV light sources positioned within a tunnel or hood that focuses the light on the battery parts 100 positioned within the tunnel (e.g., the battery parts 10Oi, j in Figure 3). The battery parts 100 can be rotated while positioned at the curing station 338 or can remain stationary. In some embodiments, the battery parts 100 are rotated at lower speed while positioned at the curing station 338 than when positioned at the sealant application station 336 from the platform 332. The output mechanism 340 can include a hopper, bin, chute, conveyer, etc., that is configured to receive the finished, cured battery parts 100. In some embodiments, the output mechanism can further include a robotic arm configured to pick and place the finished battery parts 100— for example, to position the battery parts 100 on pallets.

[0029] Some or all of the operation of the system 330 can be controlled by an automated system controller. The system controller can include a processor (e.g., a programmable logic controller (PLC)) and a memory (e.g., a computer readable media) configured to store computer-readable instructions. The processor can be configured to execute the instructions to provide operating instructions and/or commands to the various components of the system 330 and/or to receive information therefrom as described in detail above.

[0030] Several aspects of the present technology are set forth in the following examples:

1. A battery part, comprising:

a body having a lug portion extending from a base portion, wherein the base portion is configured to be a least partially embedded in battery container material; and

a light-curable material applied to at least a portion of an exterior surface of the base portion, wherein the light-curable material is configured to seal an interface between the battery part and the battery container material when the base portion is embedded in the battery container material.

2. The battery part of example 1 wherein the base portion includes a plurality of sealing portions extending radially outward relative to a longitudinal axis of the battery part, and wherein the light-curable material is applied directly to an exterior surface of the sealing portions.

3. The battery part of example 1 or 2 wherein the light-curable material includes an acrylated urethane.

4. The battery part of any one of examples 1-3 wherein the light-curable material is a masking resin that is curable via exposure to UV light.

5. The battery part of any one of examples 1-4 wherein the light-curable material is a solventless compound that is resistant to corrosion by electrolytes.

6. The battery part of any one of examples 1-5 wherein the light-curable material is omitted from an exterior surface of the lug portion.

7. The battery part of any one of examples 1-6 wherein the body further includes a circumferential flange projecting radially outward beyond the base portion, wherein the flange is configured to be at least partially embedded in the battery container material to inhibit the battery part from twisting in the battery container material, and wherein the light-curable material is applied to at least a portion of an exterior surface of the flange.

8. A method of manufacturing a battery part including a body having a lug portion and a base portion, the method comprising:

applying a sealant to at least a portion of an exterior surface of the base portion; and

exposing the sealant to light to cure the sealant, wherein the cured sealant is configured to seal an interface between the battery part and battery container material when the base portion is embedded in the battery container material.

9. The method of example 8 wherein applying the sealant includes applying a sealant that has not been dissolved in a solvent prior to applying the sealant to the base portion.

10. The method of example 8 or 9 wherein applying the sealant includes applying a masking resin including an arcylated urethane, and wherein exposing the sealant to light includes irradiating the sealant with ultraviolet light.

1 1. The method of any one of examples 8-10, further comprising embedding the base portion of the battery part in the battery container material.

12. The method of any one of examples 8-1 1 wherein the body of the battery part includes a plurality of sealing portions extending radially outward relative to a longitudinal axis of the battery part, and wherein applying the sealant includes applying the sealant to an exterior surface of the sealing portions.

13. The method of any one of examples 8-12 wherein applying the sealant to the exterior surface of the sealing portions includes applying the sealant to have a generally uniform thickness.

14. The method of any one of examples 8-13, further comprising rotating the battery part while applying the sealant and exposing the sealant to light.

15. A battery part manufacturing system, comprising:

a support configured to receive a battery part;

a sealant applicator configured to coat at least a portion of the battery part with a sealant; and

a light source configured to irradiate the sealant on the battery part to cure the sealant on the battery part.

16. The battery part manufacturing system of example 15 wherein the platform is movable to sequentially move the battery part past the sealant applicator and the light source.

17. The battery part manufacturing system of example 15 or 16 wherein the platform includes a spindle configured to releasably grasp the battery part, and wherein the spindle is rotatable to rotate the battery part relative to the sealant applicator and the light source.

18. The battery part manufacturing system of any one examples 15-17 wherein the spindle is configured to rotate the battery part at a first speed when the battery part is positioned near the sealant applicator and to rotate the battery part at a second speed, less than the first speed, when the battery part is positioned near the light source.

19. The battery part manufacturing system of any one examples 15-18 wherein the sealant applicator includes a pressurized sprayer having a spray nozzle for directing the sealant toward the battery part.

20. The battery part manufacturing system of any one examples 15-19 wherein the sealant applicator is electromechanically actuatable to vary the position of the spray nozzle relative to the battery part

[0031] From the foregoing, it will be appreciated that specific embodiments have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the present technology. For

example, in particular embodiments, details of the disclosed battery parts or battery part manufacturing systems may be different than those shown in the foregoing Figures. For example, a battery part manufacturing system may have other suitable arrangements, such as including one or more conveyors for moving the battery parts through a plurality of stations in addition to or alternatively to including one or more or rotatable platforms. Likewise, a battery part manufacturing system may include only a sealant application station or a curing station, or may include additional stations, such as a conformal coating station, a centrifugal spin station, etc. Likewise, a light-curable sealant can be applied to the battery parts of the present technology in a myriad of different manners— via rolling, dipping, painting, etc.— in addition to or alternatively to spraying the sealant on the battery parts.

[0032] Accordingly, those skilled in the art will recognize that numerous modifications or alterations can be made to the components or systems disclosed herein. Moreover, certain aspects of the present technology described in the context of particular embodiments may be combined or eliminated in other embodiments. Further, while advantages associated with certain embodiments have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the present technology. Accordingly, the inventions are not limited except as by the appended claims.