Chip-type supercapacitors

Abstract

Chip-form supercapacitor. An energy storage device suitable for mounting on a printed circuit board using a solder reflow process is disclosed. In some embodiments, the device includes: a sealed shell body (e.g., a lower body with a cover attached thereto), the sealed shell body including a positive internal contact and a negative internal contact (e.g., a metal contact pad) disposed within the body, and each contact is electrically connected to a positive external contact and a negative external contact, respectively. Each of the external contacts provides electrical connectivity to the outside of the body and may be disposed on an outer surface of the body. An electric double layer capacitor (EDLC) (also referred to herein as a "supercapacitor" or "supercapacitor") energy storage unit is disposed in a cavity in the body, comprising a stack of alternating electrode layers and electrically insulating separator layers. An electrolyte is disposed in the cavity and wets the electrode layers.

Description

[0001] This application is a divisional application of the Chinese patent application entitled “Chip-Form Supercapacitor” and application number 201880077990.5. Patent application 201880077990.5 is a national application entering the Chinese national phase based on the international application (PCT / US2018 / 054231) filed on October 3, 2018 under the Patent Cooperation Treaty. The priority date of the application is October 3, 2017.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application is filed pursuant to 37 CFR §1.53(b), and further claims the benefit of previously filed provisional application 62 / 567,752, filed on October 3, 2017, entitled “Chip Supercapacitor,” pursuant to 35 USC §1.119(e), the entire contents of which are incorporated herein by reference for any purpose. Technical Field

[0004] The present invention disclosed herein relates to energy storage devices, and in particular, to a supercapacitor configured to be mounted to a circuit board. Background Art

[0005] Most devices utilize electronics with components disposed on a circuit board. As with all electronics, an efficient power source is a necessity to power the components. One technique for providing local power on a circuit board involves the use of energy storage devices such as batteries and capacitors.

[0006] Typically, conventional capacitors provide a specific energy of less than about 360 joules per kilogram, while conventional alkaline batteries have a density of about 590 kJ / kg. Supercapacitors (also called "ultracapacitors") can accept and deliver charge faster than batteries and withstand more charge and discharge cycles than rechargeable batteries. This makes the implementation of supercapacitors an attractive solution for electrical engineers.

[0007] As a first design hurdle, a typical supercapacitor may be much larger than a conventional battery for a given charge. Even with advances in power density, there is another problem that is process-oriented. That is, the assembly of the circuit requires soldering the components to the circuit board. The heat generated by this "reflow process" is large enough to degrade or damage a conventional supercapacitor. Therefore, although the use of supercapacitors may be an attractive solution for powering electronic devices mounted on circuit boards, the solution is not available for compact designs that require high power output. In addition to this, another problem with existing supercapacitor technology is the limited life of such components.

[0008] What is needed is a supercapacitor that can be used to power electronic components disposed on a circuit board. Preferably, the supercapacitor provides a compact design that is adaptable to the ever-shrinking size of components, can withstand reflow processing and provide a useful operating life. Summary of the invention

[0009] In one aspect, an energy storage device suitable for mounting on a printed circuit board using a solder reflow process is disclosed. In some embodiments, the device includes: a sealed shell body (e.g., a lower body with a cover attached thereto), the sealed shell body including a positive internal contact and a negative internal contact (e.g., a metal contact pad) disposed within the body, and each contact is electrically connected to a positive external contact and a negative external contact, respectively. Each of the external contacts provides electrical connectivity to the outside of the body and may be disposed on an outer surface of the body. An electric double layer capacitor (EDLC) (also referred to herein as a "supercapacitor" or "supercapacitor") energy storage unit is disposed in a cavity in the body, comprising a stack of alternating electrode layers and electrically insulating separator layers. An electrolyte is disposed in the cavity and wets the electrode layers. A positive lead electrically connects a first set of one or more of the electrode layers to the positive internal contact; and a negative lead electrically connects a second set of one or more of the electrode layers to the negative internal contact.

[0010] In some embodiments, each of the electrode layers comprises an energy storage medium that is substantially free of a binder and is substantially composed of a carbonaceous material. In some embodiments, the energy storage medium comprises a carbon nanotube network defining a void space; and a carbonaceous material (e.g., activated carbon) that is located in the void space and is bounded by the carbon nanotube network. In some embodiments, at least one electrode layer comprises a double-sided electrode layer having an energy storage medium disposed on opposite surfaces of a conductive current collector layer.

[0011] In some embodiments, the surface of the energy storage cell that is in physical contact with the body is constructed of an electrically insulating material (eg, a layer of separator material, or in some embodiments, an insulating envelope barrier disposed around the cell).

[0012] In some embodiments, each of the electrode layers includes a conductive tab that is attached to either the positive lead or the negative lead. For example, a set of positive electrodes may include a tab connected to the positive lead (e.g., using ultrasonic welding or other suitable techniques) (and similarly for the negative electrode).

[0013] In various embodiments, it may be desirable to prevent corrosion and other related deleterious effects by isolating electrochemically active portions of the device that might otherwise come into contact with the electrolyte during operation. Accordingly, some embodiments include one or more anti-corrosion features, for example, features located near one of the internal contacts and configured to limit electrochemical reactions between the internal contact and the electrolyte during operation. In some embodiments, the internal contact includes a first material having a relatively high electrochemical activity with the electrolyte, and the anti-corrosion feature includes a protective layer of a second material having a relatively lower electrochemical activity with the electrolyte than the first material, the protective layer being configured to prevent contact between the first material and the electrolyte. In some embodiments, the protective layer includes a sealant layer, for example, of the type described herein. In some embodiments, the protective layer includes a metal layer disposed on a surface of the first material. In some embodiments, the protective layer includes a metal layer disposed on a surface of the first material and a sealant layer disposed on the metal layer. In some embodiments, the metal layer includes a metal gasket secured or partially secured (e.g., to the internal contact) by the sealant layer. In some embodiments, the inner surface of the body includes a recessed portion configured to receive at least a portion of the anti-corrosion feature. In some embodiments, a portion of the positive or negative lead extends through the anti-corrosion feature to connect to one of the internal contacts. In some embodiments, the anti-corrosion feature comprises an aluminum metal layer. In some embodiments, the anti-corrosion feature comprises an epoxy sealant.

[0014] Some embodiments include an electrically insulating enclosure barrier enclosing the energy storage cell and the electrolyte, the electrically insulating enclosure barrier being configured to prevent the electrolyte and the energy storage cell from contacting a surface of the cavity. In some embodiments, the lead extends from the energy storage cell through the barrier to the internal contact. In some embodiments, the barrier is heat sealed to the lead to prevent leakage of the electrolyte from within the barrier enclosure.

[0015] In some embodiments, the body is a chip configured to be surface mounted on a printed circuit board (e.g., a ceramic-based microchip package), wherein when so mounted, the chip extends no more than approximately 5.0 mm, 4.0 mm, 3.5 mm, 3.0 mm, or less above the major surface of the printed circuit board.

[0016] In some embodiments, the device may have an operating voltage of at least 2.0V, 2.1V, 2.2V, 2.3V, 2.4V, 2.5V, 3.0V or higher. In some embodiments, the device may have a capacitance of at least 300mF, 400mF, 450mF, 500mF or higher. In some embodiments, the device may have an energy density of at least 4.0J / cc, 4.5J / cc, 5.0J / cc, 5.1J / cc or higher. In some embodiments, the device may have a peak power density of at least 15W / cc, at least 20W / cc, at least 22W / cc or higher. In some embodiments, the device may have an equivalent series resistance of 500mΩ or lower, an equivalent series resistance of 400mΩ or lower, an equivalent series resistance of 300mΩ or lower. In some embodiments, the device may have an operating temperature rating of at least 65°C, 75°C, 85°C, 100°C, 125°C, 150°C or higher.

[0017] In some embodiments, the device can have an operating life of at least 2,000 hours at an operating voltage of at least 2.0V (or at least 2.1V or higher) and an operating temperature of at least 65°C, while exhibiting less than 30% degradation in capacitance and less than 100% increase in equivalent series resistance. In some embodiments, the device can have an operating life of at least 1,000 hours, at least 1,500 hours, at least 2,000 hours, at least 3,000 hours, or more at an operating voltage of at least 2.0V (or at least 2.1V or higher) and an operating temperature of at least 85°C, while exhibiting less than 30% degradation in capacitance and less than 100% increase in equivalent series resistance. In some embodiments, the device can have an operating life of at least 1,000 hours, at least 1,500 hours, at least 2,000 hours, at least 3,000 hours, or more, at an operating voltage of at least 2.0V (or at least 2.1V or more) and an operating temperature of at least 100°C, while exhibiting less than 30% degradation in capacitance and less than 100% increase in equivalent series resistance. In some embodiments, the operating life occurs after soldering the device to a printed circuit board using a reflow process having at least one, two, three, four, five, six, or more temperature cycles of at least 30 seconds, 60 seconds, 120 seconds, 180 seconds, 240 seconds, 360 seconds, or more, with a peak temperature of at least 100°C, 200°C, 250°C, 300°C, or more.

[0018] In some embodiments, the energy storage unit provides power (eg, backup power) to at least one additional component (eg, a solid-state storage device) mounted to the circuit board.

[0019] In some embodiments, the electrolyte includes an ionic liquid, which in some embodiments may be mixed with a salt and / or a solvent, such as a salt and / or solvent of the type described herein.

[0020] In some embodiments, the housing body is hermetically sealed.For example, in some embodiments, a metal cover can be attached (eg, welded) to a ceramic element to form the housing body, as described in detail herein.

[0021] In some embodiments, in the cavity of the shell body that accommodates the energy storage unit, the total concentration of halogen ions is maintained at less than about 1,000ppm, 500ppm, 200ppm, 100ppm or less. In some embodiments, in the cavity of the shell body that accommodates the energy storage unit, metal species impurities are maintained at less than about 1,000ppm, 500ppm, 200ppm, 100ppm or less. In some embodiments, in the cavity of the shell body that accommodates the energy storage unit, impurities of ethyl bromide, ethyl chloride, 1-bromobutane, 1-chlorobutane, 1-methylimidazole, ethyl acetate and dichloromethane are maintained at less than about 1,000ppm, 500ppm, 200ppm, 100ppm or less. In some embodiments, in the cavity of the shell body that accommodates the energy storage unit, moisture is maintained at less than about 1,000ppm, 500ppm, 200ppm, 100ppm, 50ppm, 10ppm or less. In some embodiments, halogen impurities within the cavity of the housing body housing the energy storage unit are maintained below about 1,000 ppm, 500 ppm, 200 ppm, 100 ppm, 50 ppm, 10 ppm, or less.

[0022] In some embodiments, the device includes a single energy storage unit housed in the sealed housing body, in other words, one energy storage unit per chip. In other embodiments, each chip may include multiple energy storage units, for example, arranged together in a common cavity, or in separate cavities, or in a combination thereof.

[0023] In another aspect, a method for manufacturing an energy storage device suitable for mounting on a printed circuit board using a solder reflow process is disclosed. In some embodiments, the method includes: forming an electric double layer capacitor (EDLC) energy storage cell comprising a stack of alternating electrode layers and electrically insulating separator layers; disposing the energy storage cell in a shell body, the body comprising a positive internal contact and a negative internal contact disposed in the body; at least partially filling the body with an electrolyte to wet the electrode layers; electrically connecting a positive lead from a first set of one or more of the electrode layers to the positive internal contact; electrically connecting a negative lead from a second set of one or more of the electrode layers to the negative internal contact; and sealing the shell body, wherein the energy storage cell is disposed in the cavity. In some embodiments, sealing the shell body includes hermetically sealing the shell body (e.g., to provide low impurity conditions as described herein).

[0024] In another aspect, a method of providing energy to a device mounted on a printed circuit board is disclosed. In some embodiments, the method may include mounting a device of the type described herein on a printed circuit board using a solder reflow process; and repeatedly charging and discharging the device at an operating voltage and an operating temperature to provide energy to the device. In some embodiments, the operating voltage is at least 2.0V, 2.1V, 2.2V, 2.3V, 2.4V, 2.5V, 2.75V, 3.0V or higher. In some embodiments, the operating temperature is at least 65°C, at least 85°C, at least 100°C, at least 125°C, at least 150°C or higher. In some embodiments, the method includes repeatedly charging and discharging the device at the operating voltage and the operating temperature to provide energy to the device for at least 2,000 hours, while the device exhibits less than 30% capacitance degradation and less than 100% equivalent series resistance increase.

[0025] Various embodiments may include any of the features and elements described herein, alone or in any suitable combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0027] Figure 1 is a schematic diagram depicting aspects of an exemplary supercapacitor;

[0028] Figure 2 is an isometric view depicting an embodiment of a chip cap according to the teachings herein;

[0029] Figure 3 yes Figure 2 Exploded view of the chip cap (from a relative perspective);

[0030] Figure 4A , Figure 4B and Figure 4C , collectively referred to as Figure 4A -C is used for Figure 2 Illustration of the electrodes of the chip cap;

[0031] Figure 5 is used for Figure 2 A depiction of a stack of energy storage media used within a memory cell of a chip cap;

[0032] Figure 6 It is used to describe Figure 2 An isometric view of a memory cell of a chip cap;

[0033] Figure 7 It is used to describe Figure 2 An isometric view of the main body of the chip cap;

[0034] Figure 8 yes Figure 7 A bottom view of the subject;

[0035] Fig. 9 Is depicted in Figure 7 within the subject Figure 6 An isometric view of a storage unit;

[0036] Fig.10 is in a state of preparation for incorporation into a storage unit Figure 7 A partial schematic diagram of a cross section of a main body;

[0037] Fig.11 yes Fig. 9 A top view of a component;

[0038] Fig.12 yes Fig.11 A cross-sectional view of the assembly shown in , the cross section being taken along the axis marked “A”;

[0039] Fig.13 It is used to describe Figure 2 A time-temperature curve diagram of the reflow of the chip cap;

[0040] Figures 14 to 16 is a graph depicting aspects of performance data for an embodiment of a chip cap;

[0041] FIG. 17A to FIG. 17B is a graph depicting aspects of performance data for an embodiment of a chip cap;

[0042] FIG. 18A to FIG. 18B is a graph depicting aspects of performance data for an embodiment of a chip cap;

[0043] Fig.19 Is to describe the use Figure 2 A schematic diagram of a chip cap system; and

[0044] Fig. 20 It is used to make Figure 2 Schematic diagram of the process flow of chip cap. DETAILED DESCRIPTION

[0045] An energy storage device for providing energy to a circuit board is disclosed herein. Typically, the energy storage device, also referred to as a "chip cap," is a specialized supercapacitor configured in a form factor suitable for surface mounting to a circuit board. Advantageously, the chip cap is able to withstand the demands associated with the manufacture and assembly of board mounted circuits and subsequently deliver performance that is superior to prior art energy storage devices.

[0046] Before introducing energy storage devices, some terminology is provided to establish the context of the teachings herein.

[0047] Embodiments of energy storage devices may be referred to herein as "supercapacitors" and also as "chip caps." The term "chip cap" generally refers to embodiments of supercapacitors suitable for surface mounting on a printed circuit board (PCB). In general, the term "chip cap" refers to a conventional microchip-type component that can be mounted on a circuit board (i.e., a chip) and the supercapacitor technology included therein.

[0048] As used herein, the term "reflowable" generally refers to the ability of the energy storage device disclosed herein to withstand the manufacturing process associated with the surface mounting of the circuit board. The manufacturing process may involve welding (i.e., reflow process), wherein the process temperature includes a heating cycle, and the heating cycle heats the component to 150 degrees Celsius, in some cases to 200 degrees Celsius, and may be heated to 220 degrees Celsius or higher. Such heating cycles may last for 30, 60, 90, 120, 240, 360 seconds or longer duration. Therefore, as discussed herein, a "reflowable" component is a component that can withstand a heating cycle suitable for incorporating the component into a board mounted circuit without experiencing substantially degraded future performance. In some embodiments, the components described herein may withstand multiple such reflow cycles, for example, two, three, four, five or more such cycles.

[0049] In some embodiments, a reflowable component may actually exhibit degraded performance, however, the degradation is expected and the final installation (ie, assembled or installed component) may exhibit predicted performance levels that are considered acceptable.

[0050] Before introducing the chip cap, the following Figure 1Some general aspects of electrochemical double layer capacitors (EDLCs) are set forth. The examples presented herein are not limiting of the present technology but are merely illustrative and provided for purposes of explanation.

[0051] Figure 1 Depicted are concepts associated with an exemplary embodiment of an electrochemical double layer capacitor (EDLC) 10, also referred to as a "supercapacitor". The supercapacitor 10 includes two electrodes (a negative electrode 3 and a positive electrode 4), each electrode 3, 4 having a double layer charge at an electrolyte interface. In some embodiments, it includes a plurality of electrodes. However, for purposes of discussion and illustration, Figure 1 Only two electrodes 3, 4 are shown. In this document, as a convention, each of the electrodes 3, 4 uses a carbon-based energy storage medium 1 (as discussed further herein) to provide energy storage.

[0052] Each of the electrodes 3, 4 includes a respective current collector 2. In the supercapacitor 10, the electrodes 3, 4 are separated by a separator 5. Typically, the separator 5 is a thin structural material (usually a sheet) used to separate the electrodes 3, 4 into two or more compartments.

[0053] At least one form of electrolyte 6 is included. The electrolyte 6 fills the void space within and between the electrodes 3, 4 and the separator 5. Typically, the electrolyte 6 is a chemical compound that decomposes into charged ions. In some embodiments, a solvent that dissolves the chemical compound may be included. The resulting electrolytic solution conducts electricity through ion transport.

[0054] For convenience, the combination of electrodes 3 , 4 , separator 5 and electrolyte 6 is referred to as a “memory cell 12 ”. In some embodiments, the term “memory cell” refers only to electrodes 3 , 4 and separator 5 without electrolyte 6 .

[0055] Typically, the exemplary supercapacitor 10 is encapsulated in a housing 7 (which may be simply referred to as "housing 7") in a manner further discussed herein. Housing 7 is hermetically sealed. In various examples, the package is hermetically sealed by techniques utilizing laser, ultrasonic and / or welding techniques. Housing 7 (also referred to as "housing") includes at least one terminal 8. Each terminal 8 provides electrical access to the energy stored in the energy storage medium 1.

[0056] In the exemplary EDLC 10, the energy storage medium 1 may be provided by and include activated carbon, carbon fiber, rayon, graphene, aerogel, carbon cloth and / or carbon nanotubes. For example, an activated carbon electrode may be manufactured by the following method: a carbon substrate is manufactured by subjecting a carbon material obtained by carbonizing a carbon compound to a first activation treatment; a shaped body is manufactured by adding a binder to the carbon substrate; the shaped body is carbonized; and finally, an activated carbon electrode is manufactured by subjecting the carbonized shaped body to a second activation treatment.

[0057] Carbon fiber electrodes can be produced, for example, by using paper or cloth preforms having high surface area carbon fibers.

[0058] In a specific example, multi-walled carbon nanotubes (MWNTs) are fabricated on multiple substrates using chemical vapor deposition (CVD) for electrodes 3, 4. In one embodiment, low pressure chemical vapor deposition (LPCVD) is used. The fabrication process may use a gas mixture of acetylene, argon, and hydrogen, and an iron catalyst, which is deposited on the substrate by electron beam deposition and / or sputtering deposition.

[0059] In some embodiments, the material used to form the energy storage medium 1 may include materials other than pure carbon. For example, various material formulations for providing a binder may be included. However, typically, the energy storage medium 1 is substantially formed of carbon and is therefore referred to as a "carbonaceous material."

[0060] In short, although formed primarily of carbon, the energy storage medium 1 may include any form of carbon, as well as any additives or impurities deemed appropriate or acceptable to provide the desired functionality as the energy storage medium 1 .

[0061] The electrolyte 6 includes a plurality of pairs of cations 9 and anions 11 and, in some embodiments, may include a solvent. Various combinations of each may be used. In an exemplary EDLC 10, cation 11 may include 1-(3-cyanopropyl)-3-methylimidazolium, 1,2-dimethyl-3-propylimidazolium, 1,3-bis(3-cyanopropyl)imidazolium, 1,3-diethoxyimidazolium, 1-butyl-1-methylpiperidinium, 1-butyl-2,3-dimethylimidazolium, 1-butyl-3-methylimidazolium, 1-butyl-4-methylpyridinium, 1-butylpyridinium, 1-decyl-3-methylimidazolium, 1-ethyl-3-methylimidazolium, 3-methyl-1-propylpyridinium, and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, and combinations thereof, and other equivalents deemed appropriate.

[0062] In an exemplary EDLC 10, anions 9 may include: bis(trifluoromethanesulfonate)imide, tris(trifluoromethanesulfonate)methide, dicyanamide, tetrafluoroborate, hexafluorophosphate, trifluoromethanesulfonate, bis(pentafluoroethanesulfonate)imide, thiocyanate, trifluoro(trifluoromethyl)borate, spiro-(1,1′)-bipyrrolidinium tetrafluoroborate, another potential salt is tetraethylammonium tetrafluoroborate, and combinations thereof, as well as other equivalents deemed appropriate.

[0063] Solvents can include acetonitrile, amides, benzonitrile, butyrolactone, cyclic ethers, dibutyl carbonate, diethyl carbonate, diethyl ether, dimethoxyethane, dimethyl carbonate, dimethylformamide, dimethyl sulfone, dioxane, dioxolane, ethyl formate, ethylene carbonate, ethyl methyl carbonate, lactones, linear ethers, methyl formate, methyl propionate, methyltetrahydrofuran, nitrile, nitrobenzene, nitromethane, n-methylpyrrolidone, propylene carbonate, sulfolane, sulfone, tetrahydrofuran, tetramethylene sulfone, thiophene, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, carbonates, gamma-butyrolactone, nitrile, tricyanohexane, butyronitrile, ethylene carbonate, and dichloromethane, any combination thereof, or other materials exhibiting appropriate performance characteristics.

[0064] The separator 5 can be made of non-woven glass. The separator 5 can also be made of glass fiber, fluoropolymer, Teflon (PTFE) and ceramics. For example, using non-woven glass, the separator 5 may include main fibers and binder fibers, each of which has a fiber diameter smaller than that of each of the main fibers and allows the main fibers to be bonded together.

[0065] The foregoing description of concepts related to the ultracapacitor 10 provides background for the chip cap disclosed herein and discussed below.

[0066] exist Figure 2 and Figure 3 In the illustration of , the chip cap 100 includes a body 101 and a cover 102 mounted thereon. A volume 103 is provided within the body 101 and the cover 102, the volume 103 containing a chip cap storage unit 105 immersed in an electrolyte 126 or wetted by the electrolyte 126. The body 101 may also be referred to as a part of the housing 7, or as a "container" or "package" and other similar terms. In general, the chip cap storage unit 105 operates by the principles described above with respect to the supercapacitor storage unit 12. Other aspects of the chip cap storage unit 105 (hereinafter referred to as "storage unit 105") will be described below.

[0067] In some embodiments, the main body 101 and the cover 102 mounted thereon can have a size selected to be suitable for microelectronic applications. For example, in some embodiments, the main body 101 and the cover mounted thereon are configured to be surface mounted on a printed circuit board, wherein when so mounted, the main body 101 and the cover 102 extend no more than about 5.0mm, 4.0mm, 3.5mm, 3.0mm or less above the main surface of the printed circuit board. In some embodiments, the maximum lateral dimension of the main body 101 is less than about 5.0cm, 4.0cm, 3.0cm, 2.0cm, 1.0cm, 0.5cm, 0.25cm or less. In some embodiments, the main body 101 occupies a lateral surface area less than 25.0cm^2, 16.0cm^2, 9.0cm^2, 1.0cm^2, 0.25cm^2, 0.1cm^2, 0.075cm^2, 0.05cm^2 or less.

[0068] In some embodiments, the side of the cover 102 facing the interior of the body 101 may include a protective coating or layer (e.g., a polymer or plastic material such as PTFE or polyimide) to prevent undesired physical or electrical contact between the cover and the storage unit 105.

[0069] The process of building the chip cap 100 begins with the fabrication of the memory cells 105 and the preparation of the body 101 .

[0070] The first step in constructing the memory cell 105 involves the preparation of electrodes. Figure 4A An example of a double-sided electrode 600 is shown in FIG. Figure 4A As shown in FIG. 6 , each double-sided electrode 600 includes a current collector 2 with an energy storage medium 1 disposed on either side thereof.

[0071] Some embodiments of the electrode include five main components. These components include an aluminum current collector 2, a polymer primer layer (also referred to as an "active material") provided to promote adhesion of the energy storage medium 1, and a three-component active material. The active material may include, for example, activated carbon (to enhance capacitance), carbon black (to provide high conductivity and reduce equivalent series resistance (ESR)), and a polymer binder (to hold the powder together).

[0072] In some embodiments, carbon nanotubes (CNT) are used as alternative materials to provide bonding and cohesive matrix. That is, the primer can be replaced by a CNT adhesion layer (AL), and the polymer binder for active materials can also be replaced by CNT. CNT can also reduce or replace carbon black as a conductive aid. The electrode produced (i.e., an electrode that does not include a polymer or other binding material) is "adhesive-free". Such adhesive-free electrodes can advantageously operate under extreme conditions (e.g., high pressure and / or high temperature) without deteriorating due to electrochemical reactions between adhesives and surrounding materials (e.g., electrolytes). Without wishing to be bound by theory, in some embodiments, it should be understood that the electrostatic attraction (e.g., van der Waals bonds) between the carbons in the adhesive-free electrode provides sufficient adhesion and cohesion, thereby maintaining the integrity of the electrode even under harsh conditions. For example, in some embodiments, the binderless electrodes can exhibit little or no deleterious delamination even when subjected to a reflow process (as described in detail herein) or when subjected to an operating voltage of at least 2.0 V, or at least 2.1 V or more at an operating temperature of 65°C, 85°C, 100°C, 125°C, 150°C, or more.

[0073] In some embodiments of the binderless electrode, the active medium includes activated carbon (or other types of carbonaceous materials) bound together by a carbon nanotube (CNT) matrix, and the active layer is a carbon nanotube (CNT) matrix without any other fillers. Advantageously, (e.g., to reduce manufacturing costs), in some embodiments, the weight concentration of CNTs in the active layer can be relatively low, for example, less than 50%, 40%, 30%, 20%, 10%, 7.5%, 5.0%, 2.5% or less, depending on the desired performance characteristics of the electrode.

[0074] In some embodiments, activated carbon powder and / or powder containing carbon nanotubes (CNTs) are dispersed in isopropanol using ultrasonic treatment and sufficient energy to debundle the carbon nanotubes (CNTs) from each other to obtain a matrix. Successful dispersion can be characterized by material separation and appearance. For example, whether the carbon nanotube (CNT) material is separated from the solvent and whether a smooth film appears when dried.

[0075] The cohesive and adhesive strengths of the active medium and active layer, respectively, are affected by the dispersion quality of the CNTs in their slurries (as well as the CNT properties, drying time, layer thickness, substrate material, substrate structure, etc.). The dispersion of CNTs is affected by the solvent selection (and CNT properties; concentration; material purity; use of surfactants; batch size; dispersion settings, such as sonicator amplitude, duty cycle, temperature, probe depth, stirring quality; etc.).

[0076] The adhesion of the active medium to the current collector 2 can be improved by adding an adhesion layer (AL) of carbon nanotubes (CNT) to the current collector 2. This can be achieved by casting and drying a layer of active medium on a stainless steel (SS) plate, pressing a different plate with vertically aligned carbon nanotubes against a current collector 2 coated with aluminum carbide using a roll-to-roll machine to transfer the carbon nanotubes (CNT), and then pressing the plate with the active medium against the current collector 2 / carbon nanotube (CNT) layer to form an electrode.

[0077] In some embodiments, the electrode is produced by casting a thin layer of carbon nanotube (CNT) slurry directly onto the current collector 2, allowing the thin layer to dry, and then casting the active medium slurry on top.

[0078] Several techniques can be used to place all active media layers on the electrode. In one embodiment, it involves rolling, casting and drying a layer of active media on a stainless steel (SS) plate, then pressing a different plate with vertically aligned carbon nanotubes (VACNT) against an aluminum carbide coated current collector 2 to transfer the vertically aligned carbon nanotubes (VACNT), and then pressing the plate with active media against the aluminum carbide coated current collector 2 with the vertically aligned carbon nanotube (VACNT) layer to form the electrode. In another embodiment, a thin layer of carbon nanotubes (CNT) is cast directly onto the current collector 2 as a slurry, dried, and then the active media is cast as a slurry on top of the thin layer of carbon nanotubes (CNT).

[0079] The selection of activated carbon includes an assessment of capacitance versus lifetime. That is, it has been found that there is often a tradeoff between the highest capacitance material and the longest lifetime material. In general, it has been found that the quality of the activated carbon should be determined empirically. It was found that regarding the selection of the active material carbon nanotube (CNT) powder: longer carbon nanotubes (CNTs) lead to a stronger matrix; the lower number of walls in the carbon nanotubes (CNTs) is better in terms of density efficiency; the high purity of the carbon nanotubes (CNTs) avoids reactive contents; the pores can be oxidized to expose the inner surface of the carbon nanotubes (CNTs), but may lead to the addition of impurities. Regarding the selection of the adhesion layer powder, it was found that: for length, the relationship between cohesion and adhesion should be evaluated as carbon nanotubes (CNTs) that are too long will self-adhere too well and peel off the current collector 2; and thinner layers of CNTs mitigate the risk of peeling off the current collector 2. Regarding the calendaring technology: the carbon nanotube (CNT) matrix can be "activated" under pressure, and the degree of powdering becomes less after the CNTs are bonded together. Higher pressures give better density, but with diminishing returns; in some cases, starting the calendaring process at low pressure and working with added passes seems to help adhere the layers. Care should be taken to avoid overworking as this can lead to delamination. More calendering passes may increase density slightly, but the risk of overworking or wrinkling the current collector 2 will increase.

[0080] The adhesion layer may include carbon nanotubes (CNTs), carbon nanofibers, metal nanowires, and ceramic nanofibers. For active material cohesion, carbon nanotubes (CNTs) may be used, as well as carbon nanofibers, metal nanowires, and / or ceramic nanofibers. For active material energy storage: activated carbon may be used; and / or carbon black; additional carbon nanotubes (CNTs); soot; jet black; buckeye balls; fullerenes; graphite; graphene; nanohorns; nano onions, and other forms of carbon. The carbon nanotubes (CNTs) used may be single-walled, double-walled, multi-walled, of any length, diameter, purity, crystallinity, or other aspects as deemed appropriate.

[0081] In various embodiments, the size of the electrode ranges from about 20 μm to about 350 μm. In various embodiments, the thickness of the current collector ranges from about 10 μm to about 50 μm. In various embodiments, the thickness of the adhesion layer is between about 2 μm and about 10 μm or more. The thickness of the active material disposed on the adhesion layer may be between about 5 μm and about 150 μm or more. In some embodiments, the diameter of the carbon nanotubes (CNTs) used in the adhesion layer is between 1 nm and about 200 nm, the length is between about 1 μm and about 1000 μm, and the number of walls is between about 1 and 100. In some embodiments, the diameter of the carbon nanotubes (CNTs) used in the active material is between 1 nm and about 200 nm, the length is between about 1 μm and about 1000 μm, and the number of walls is between about 1 and 100. In some embodiments, the active material includes substantially spherical particles exhibiting a diameter between about 2 μm and about 30 μm.

[0082] In some embodiments, compression of the energy storage medium is applied after drying. Typically, this helps lock the carbon nanotubes (CNTs) in place. A roller press, hydraulic press, or other type of press may be used. Care should be taken to avoid damage to the current collector.

[0083] In various embodiments, the electrode layer may be formed using any of the techniques described in International Patent Publication No. WO / 2018 / 102652, published on June 7, 2018, the entire contents of which are incorporated herein by reference.

[0084] In order to provide current collection from a set of positive electrodes and from the negative electrodes, multiple left-hand side ( Figure 4B ) and right-hand side ( Figure 4C ) double-sided electrode 600. Typically, each of the left-hand side or right-hand side double-sided electrode 600 includes an energy storage medium 1 disposed on either side thereof, and includes a conductive lead 602 that is substantially free of the energy storage medium 1.

[0085] Electrodes can be punched out of a sheet of material using a suitable press. Electrodes punched out of a sheet of material exhibit appropriate dimensions for the storage cell 105. Once the sized electrodes are cut, they can be prepared. The preparation of the sized electrodes may include, for example: calendering each electrode to ensure retention of the energy storage medium 1; trimming of the edges; and heat treatment to promote migration and reduction of any impurities. After preparation, the electrodes can be transferred to a suitable environment to prepare the assembly.

[0086] Once manufactured and qualified, the double-sided electrode 600 is included in the stack assembly. For assembly of the stack, a suitable separator 5 is provided. The separator 5 may be made of a separator material.

[0087] In some embodiments, separator 5 is cut from a supply of separator material, which in one embodiment is a supply of polytetrafluoroethylene (PTFE). PTFE is a synthetic fluoropolymer of tetrafluoroethylene (commonly known as TEFLON, available from Chemours, Delaware). PTFE is a fluorocarbon solid because it is a high molecular weight compound composed entirely of carbon and fluorine. In an exemplary embodiment, separator 5 is 25 μm thick. Figure 5 An example of an active stack assembly having a single separator 5 is shown in FIG.

[0088] Figure 5 Depicted are conceptual aspects of a "z-fold" arrangement of an energy storage medium 1. In a z-fold embodiment, a layer of separator 5 is formed from a single sheet of separator material folded in a z-fold manner. The z-fold separator 5 includes opposing positive and negative electrodes 4 and 3 and associated current collectors 2 folded therein. Generally, as referred to herein, an assembly of multilayer electrodes, current collectors, and separators is referred to as a "stack 201," which may also be referred to as an "active stack" and other similar terms.

[0089] In order to manufacture the z-folded stack 201, and once the separator 5 is cut, the first of the double-sided electrodes 600 is disposed on the end of the separator 5. The separator 5 is then folded, and the opposite double-sided electrode 600 is disposed on the separator 5. The process continues until a complete stack 201 is provided. In one embodiment, the complete stack 201 includes fifteen double-sided electrodes 600. In this example, the complete stack 201 will have eight (8) layers of electrodes on the negative electrode side and seven (7) layers of electrodes on the positive electrode side. In this embodiment, each double-sided electrode 600 has an area of ​​energy storage material 1 of approximately 6 mm×8 mm. The exposed portion of the current collector 2 used as an integrated lead has a size of approximately 1.5 mm×8 mm.

[0090] Typically, stack 201 is configured to provide a desired level of electrical performance. Stack 201 need not be nor is it necessary to be provided in a z-folded arrangement. In some embodiments, each layer of stack 201 is separated by a separate separator 5. In some embodiments, each layer of stack 201 can be contained within an envelope of separator material (i.e., surrounded by it).

[0091] Similarly, the entire storage unit 105 can be arranged in an envelope of a separator material or other suitable protective barrier (e.g., electrically insulating thermoplastic or other suitable material). In some embodiments, the envelope can accommodate the electrolyte that wets the stack 201, thereby preventing the electrolyte from contacting elements outside the barrier. In some such embodiments, the conductive lead 602 can extend through the envelope to provide electrical communication between the stack 201 and the lead (123, 124). Alternatively, in some embodiments, the lead (123, 124) can extend through the envelope to connect to the lead 602. Typically, the envelope can be sealed (e.g., heat sealed) around such electrical connectors to prevent electrolyte from leaking out of the envelope.

[0092] In various embodiments, the storage unit 105 may be configured using any of the techniques described in International Patent Publication No. WO2015102716A8 published on November 26, 2015 or International Patent Publication No. WO2016057983A3 published on June 30, 3016, the entire contents of each of which are incorporated herein by reference.

[0093] In some embodiments, the stack 201 is configured by cutting (e.g., using a blade or cutting laser) or punching out electrode layers from a thin sheet of electrode material. The electrode material may include a thin sheet of material suitable for use as a current collector 2, with the energy storage material 1 disposed on either side. The alternating layers within the stack 201 constitute the negative electrode and the positive electrode. The separator material is interlaced between each layer and wrapped around the final assembly to form a complete stack 201.

[0094] Because stack 201 accommodates multiple layers of electrodes, there are multiple conductive leads 602. Multiple conductive leads 602 extend beyond energy storage medium 1 and provide electrical contact. In stack 201, conductive leads 602 are grouped according to polarity and formed into a single negative lead 123 and a single positive lead 124. Together, the assembly of stack 201 with negative lead 123 and positive lead 124 provides storage cell 105. Figure 6 An illustration of the storage unit 105 in assembled form is provided in FIG.

[0095] In some embodiments, grouping the conductive leads 602 into a corresponding one of a single negative lead 123 and a single positive lead 124 is performed by pre-bending the conductive leads before assembling the storage unit 105. When the storage unit 105 is disposed in the body 101, the group of conductive leads 602 is welded to the corresponding pads 110 ( Figure 7 ) thereby forming an integral lead (123, 124). Welding can be accomplished by, for example, ultrasonic welding or laser welding.

[0096] Figure 7 Aspects of the body 101 are depicted. The body 101 of the chip cap 100 may be made of a dielectric material such as various forms of ceramic materials. The body 101 includes electrical pads 110 therein for conducting current from the storage cell 105 once disposed therein. The electrical pads 110 may also conduct current to the storage cell 105 in order to recharge the chip cap 100.

[0097] exist Figure 7 In the illustration of FIG. 1 , the body 101 generally includes a bottom 111 and four walls 112 extending around the periphery of the bottom 111. Thus, the body 101 provides a container in which the storage unit 105 can be disposed. Figure 8 The underside of this example of the body 101 is shown in FIG.

[0098] like Figure 8 1 , the underside of the bottom 111 of the body 101 includes electrical contacts 121 separated by dielectric material 120. At least some of the contacts 121 are in electrical communication with the electrical pads 110 and enable energy to be transmitted from the chip cap storage unit 105 to a circuit board on which the chip cap 100 can be mounted. Typically, energy is transmitted from the electrical pads 110 to the contacts 121 via electrical conductors or through-holes (not shown) housed within the body 101 and surrounded by the dielectric material 121. For example, in some embodiments, the body can house one or more conductive plates (e.g., embedded within the bottom 110 of the body 101) to establish electrical communication between the electrical pads 110 and the contacts 121. These plates can be made of, for example, tungsten or other suitable conductive materials.

[0099] Therefore, for each of the double-sided electrodes 600, a conductive path is formed from the collector 2, via the conductive lead 602, via the corresponding lead (123, 124) to the corresponding electrical pad 110, and then from the electrical pad 110 via the conductive through-holes within the body 101 to one or more contacts 121 on the bottom surface of the body 101.

[0100] The internal electrical pads 110 are exposed to a volume 103 (also referred to herein as a "cavity") within the body 101. The cover 102 may include a compatible material, such as a ceramic or metallic material. During assembly of the chip cap 100, the cover 102 is hermetically sealed to the body 101 by being sealed to the sealing ring 114. The resulting hermetic seal exhibits environmental integrity by preventing environmental intrusion into the chip cap 100 and electrolyte leakage from the chip cap 100. The hermetic seal includes any type of seal that makes the chip cap 100 substantially hermetic (excluding the passage of electrolyte, air, oxygen, or other materials in gaseous form) to ensure adequate performance within the expected service interval.

[0101] Examples of devices suitable for use as body 101 include those in the surface mount device (SMD) product line commercially available from NTK Technologies of Nagoya, Japan. Other examples are available from Schott AG of Landshut, Germany and Adtech Ceramics Company of Chattanooga, Tennessee.

[0102] In some embodiments, body 101 is a high temperature co-fired ceramic device. Typically, a co-fired ceramic device is a monolithic ceramic microelectronic device in which the entire ceramic support structure and any conductive, resistive, and dielectric materials are fired simultaneously in a kiln.

[0103] Typically, co-fired ceramic devices are manufactured by processing multiple layers independently and assembling them into a device as a final step. Co-firing can be divided into low-temperature (LTCC) and high-temperature (HTCC) applications: low-temperature devices are manufactured with sintering temperatures below 1,000 degrees Celsius (1,830 degrees Fahrenheit), while high-temperature is around 1,600 degrees Celsius (2,910 degrees Fahrenheit). HTCC has a higher resistance conductive layer than LTCC.

[0104] HTCC packages typically include multiple layers of aluminum oxide (Al2O3) with tungsten (W) and molybdenum (MoMn) metallization. Advantages of HTCC include mechanical rigidity and hermeticity, both of which are important in high reliability and environmentally stressed applications. Another advantage of HTCC technology is the ability to dissipate heat.

[0105] Typical ceramic packages use alumina ceramic (Al2O3), which exists in different purities and compositions to support different applications. A typical ceramic package may be composed of 90-94% alumina, with the remainder composed of alkaline earth silicates or other binding materials, such as magnesium oxide (MgO) or silicon dioxide (SiO2), used to control the particle size and bind the alumina together.

[0106] The body 101 may be provided as a multilayer ceramic package having a metallization layer that carries power from the storage unit 105 to the external contacts 121. The metallization layer may be made of tungsten (W) or molybdenum manganese alloy (MoMn) in the case of high temperature co-fired ceramic (HTCC), or gold (Au) or copper (Cu) in the case of low temperature co-fired ceramic (LTCC).

[0107] Typically, a plating process is performed on the metallization layer to protect the metallization layer from oxidation. If a metallization process (such as the gold (Au) metallization process used in LTCC) is employed, no additional plating is required. Typically, the plating layer includes nickel (Ni) as a base, followed by a thin (about 0.3 μm) layer of gold (Au) for oxidation protection. Alternative plating metals include titanium (Ti) and palladium (Pd). The selected combination of plating metals can be about forming strong and reliable wire bonds.

[0108] It is worth noting that when the storage unit 105 is placed in the main body 101 ( Fig. 9 ), the elements of the stack 201 (i.e., the current collector 2 and the energy storage medium 1) can be separated from the body 101 (and / or the cover 102) by a layer of separator material. This embodiment is referred to as an "isolated stack" and results in substantial protection against potential failures due to short circuits of the storage cells 105. In some embodiments, the isolated stack is achieved by providing the storage cells 105 in an electrically insulating envelope (such as an envelope made of a separator material). Once the storage cells 105 have been manufactured, they can be set aside for subsequent installation into the body 101.

[0109] The body 101 may be manufactured according to desired specifications such as size, electrical design, environmental quality, etc. At least one pocket or well may be added to confine the sealant to the area around the electrical pad 110 .

[0110] like Fig.10 As shown in FIG. 1 , in some embodiments, the electrical pads 110 are disposed within corresponding wells 205. Each well 205 represents a depression within the top surface of the base 111. Typically, the space provided by each well 205 can be used to fold a portion of the corresponding lead (123, 124), thereby maximizing the volume available for the stack 201. Note that the term "well" can be used interchangeably with other terms, such as "recessed portion," "depression," "pocket," and other similar terms.

[0111] Each electrical pad 110 may be a homogeneous material. For example, the electrical pad 110 may be one of tungsten (W), aluminum (Al), gold (Au), or another conductive material. In some embodiments, the electrical pad 110 is plated with an optional plating material. The plating layer or simply the plating 131 may include, for example, gold (Au), nickel (Ni), or copper (Cu). In some further embodiments, the electrical pad 110 is layered. For example, the electrical pad 110 may accommodate an inner layer of tungsten (W) with a nickel (Ni) cover layer. The nickel (Ni) cover layer has a gold (Au) plating 131.

[0112] Typically, the materials used in the electrical pad 110 and any plating 131 are selected for a balance of conductivity and low reactance with the selected electrolyte 126. Limited interaction of the electrolyte is further achieved by appropriate preparation of the body 101 and bonding of the leads (123, 124). At least one sealant may be used as part of the preparation and bonding.

[0113] In particular, gold (Au), nickel (Ni) and tungsten (W) may experience corrosion in the presence of common electrolytes when under voltage potential. Corrosion generated at the coating or metallization layer will cause premature degradation of the electrolyte and solder joints, reducing the performance of the chip cap 100. Therefore, a non-reactive sealant can be used to prevent contact between the coating / metallization layer and the electrolyte. As discussed herein, the term "non-reactive" generally refers to a substance that exhibits a level of reactivity that is believed to provide a relative performance improvement.

[0114] For each of the electrical pads 110, a conductive lead 210 may be bonded to the electrical pad 110. For example, the bonding may be by welding. The welding may be laser welding, ultrasonic welding, or resistance welding. In some other embodiments, a conductive epoxy may be used to bond the conductive lead 210 to the electrical pad 110. In some embodiments, the conductive lead 210 is formed of aluminum (Al). The configuration of the conductive lead 210 may vary depending on, for example, the location of the corresponding electrode and the configuration of the body 101.

[0115] In one embodiment, the conductive lead 210 is one of the leads (123, 124) for the electrode stack 201. In these embodiments, welding may be required only to join the electrode stack 201 to the body 101. In another embodiment, the conductive lead 210 is an intermediate material that is initially separated from the corresponding lead (123, 124) and the electrical pad 110. Then, the conductive lead 210 is joined to the corresponding lead (123, 124) after applying the sealant.

[0116] Once the conductive lead 210 has been bonded to the electrical pad 110, the sealant may flow onto the area around the pad 110 and the area around the conductive lead 210. The sealant is then cured. The curing method may involve curing a suitable sealant material using heat, ultraviolet radiation, water / oxygen, evaporation, or by other techniques.

[0117] In various embodiments, other sealant technologies may be used. For example, in some embodiments, a conformal layer of sealant may be deposited over the desired portion of the package. Typically, the conformal layer comprises a thin film that "conforms" to the contours of the body 101 to account for any imperfections and limit its permeability. The conformal layer may be provided as a high viscosity component that flows easily.

[0118] Generally, for any conformal coating method used to passivate the internal electrical pads 110, care is taken to keep the conformal coating from covering external features, sealing rings, and other appropriate features. In some embodiments, the material selected for the conformal coating does not interfere with the bonding process (such as soldering).

[0119] In one embodiment, the conformal coating comprises a high temperature thermoplastic polyimide. The high temperature thermoplastic polyimide can be provided as a material that can be dispensed by a syringe, exhibiting a viscosity slightly higher than that of water. The thickness of the insulating layer of the resulting material can be between about 3-20 μm, exhibiting a strong bond with ceramics, aluminum, gold, silicone and other materials. In some embodiments, the high temperature thermoplastic polyimide can include silver or other metal flakes to make the material conductive. In one embodiment, the high temperature thermoplastic polyimide is stored at about minus 40 degrees Celsius, operates at ambient temperature, and is subjected to a curing cycle of about 10 minutes at about 150 degrees Celsius. The curing cycle will cause the high temperature thermoplastic polyimide to crystallize and release most of the excess material (NMP and H2O) in gaseous form. An additional heating cycle of about two minutes and about 250 degrees Celsius can be performed to remove the excess material. The method results in a conformal coating with high insulating properties and very low thermal expansion.

[0120] Examples of suitable materials are available from Advanced Engineered Materials (MATERION), Inc. of Buffalo, NY, and sold under the trade name BONDFLOW. BONDFLOW includes RM 1-methyl-2-pyrrolidone (CAS 872-50-4).

[0121] Once the stack 201 is positioned into the body 101 and electrically connected to the electrical pads 110 , the electrolyte 126 is added to the remaining volume 103 within the body 101 .

[0122] In some embodiments, electrolyte 126 is a combination of an ionic liquid, an ionic salt, and a solvent. Typically, the ionic liquid and the solvent are mixed together to obtain a mixture. The mixture can be a completely solvent-free ionic liquid. In some embodiments, the electrolyte is about 20 percent ionic liquid and 80 percent solvent (by volume). Mixtures within a sub-range can be used.

[0123] Typically, ionic salts can be added to the ionic liquid as an additional source of ion storage, where different cation and anion sizes are provided to increase efficiency given the surface area provided by the electrodes. The ionic salts can be added to the mixture in a range of about 0M to 2M (moles, or moles of salt per liter of solution).

[0124] Subsequently, the main body 101 and the storage unit 105 installed therein can be weighed and then filled with an appropriate amount of electrolyte. Filling can occur, for example, by using a micropipette. Once filled, the combination of the main body 101 / storage unit 105 can be placed in a low pressure environment (i.e., under vacuum). The low pressure causes the electrolyte 126 to migrate into the storage unit 105. Subsequently, the assembly can be weighed again to ensure an adequate supply of electrolyte 126. If the combined main body 101, storage unit 105 and electrolyte assembly are within the desired parameters, the assembly is sent for welding of the cover 102. The cover 102 can then be welded to the main body 101. Welding can be completed in an inert environment using, for example, a seam welder.

[0125] In various embodiments, care is taken to avoid unwanted impurities within the volume 103 housing the storage cell 105. In some embodiments, within the cavity of the shell body housing the energy storage cell, the total concentration of halogen ions is maintained below about 1,000 ppm, 500 ppm, 200 ppm, 100 ppm, or less. In some embodiments, within the cavity of the shell body housing the energy storage cell, metal species impurities are maintained below about 1,000 ppm, 500 ppm, 200 ppm, 100 ppm, or less. In some embodiments, within the cavity of the shell body housing the energy storage cell, impurities of ethyl bromide, ethyl chloride, 1-bromobutane, 1-chlorobutane, 1-methylimidazole, ethyl acetate, and dichloromethane are maintained below about 1,000 ppm, 500 ppm, 200 ppm, 100 ppm, or less. In some embodiments, the moisture in the cavity of the shell body that accommodates the energy storage unit is maintained at less than about 1,000ppm, 500ppm, 200ppm, 100ppm, 50ppm, 10ppm or less. In some embodiments, the halogen impurities in the cavity of the shell body that accommodates the energy storage unit are maintained at less than about 1,000ppm, 500ppm, 200ppm, 100ppm, 50ppm, 10ppm or less.

[0126] In various embodiments, the electrolyte may be any type described in International Patent Publication No. WO2015102716A8 published on November 26, 2015 and International Publication No. WO2016204820A2 published on December 22, 2016, the entire contents of each of which are incorporated herein by reference. For example, in some embodiments, the electrolyte may include a gel or solid electrolyte of the type described in the aforementioned references.

[0127] Fig.11 supply Fig. 9 A top view of the components. Fig.11 In the figure, the storage unit 105 and the main body 101 are bisected by an imaginary axis -A. Fig.12 1 is a cross-sectional depiction of the storage unit 105 and the main body 101 along the imaginary axis -A.

[0128] like Fig.12As shown in , the storage cell 105 includes multiple layers. Multiple conductive leads 602 extend from the multiple layers. In the cross section, multiple conductive leads 602 are gathered together to collectively provide a negative lead 123. During assembly, the negative lead 123 is formed into an appropriate shape and joined to a corresponding one of the electrical pads 110, and the same process occurs for the positive lead 124 (not shown in the cross-sectional view). Subsequently, the body 101 is filled with an embodiment of an electrolyte 126 suitable for the chip cap 100. The electrolyte 126 wets the leads (123, 124) and the contents of the storage cell 105.

[0129] In some embodiments, the energy storage unit 105 can be a symmetrical EDLC, in which equal masses of active materials are provided on the positive and negative electrodes of the capacitor. However, if the sizes of the anions and cations in the electrolyte are different, having equal electrode masses can prevent the EDLC from having the maximum possible specific capacitance because the electrodes and electrolyte may not be fully utilized. In some embodiments, the problem can be solved by mass balance by adjusting the electrode mass according to the size of the ions (e.g., increasing the EDLC specific capacitance). In some embodiments, the stack 201 can include unequal numbers of positive electrode layers and negative electrode layers to provide improved mass balance.

[0130] The resulting chip cap 100 is robust to manufacturing processes that typically damage competitive devices. An example of such a manufacturing process is "reflow". In the reflow process, the component is heated to a temperature sufficient to cause the solder to flow. Generally, efficient mass production of electronic components requires the use of a reflow process. In addition, compact designs often utilize surface mount devices to limit the space utilized by the components and are also dependent on reflow processing.

[0131] In one embodiment, chip cap 100 is mounted on a printed circuit board according to a recommended solder reflow profile. Fig.13 A graphical depiction of time versus temperature is provided in Fig.13 In the example of FIG. 1 , the temperature is increased at three (3) degrees Celsius per second to a preheat stage (referred to as a "soak"). During the preheat stage, the chip cap 100 is maintained at a temperature between about 150 degrees Celsius and about 160 degrees Celsius for about 100 seconds. The temperature is then increased at a rate of three (3) degrees Celsius per second to a reflow temperature (referred to as "reflow"). The reflow temperature may reach about 260 degrees Celsius. Typically, the time above 200 degrees Celsius should be less than about 60 seconds, after which the mounted chip cap 100 is cooled at a rate of about 6 degrees Celsius or less.

[0132] In some embodiments, chip cap 100 can exhibit less than 10%, 5%, 2.5% or less degradation in capacitance in response to one, two, three, four or more reflow cycles. In some embodiments, chip cap 100 can exhibit less than 10%, 5%, 2.5% or less increase in ESR in response to one, two, three, four or more reflow cycles. In some embodiments, the reflow process can even advantageously increase capacitance and / or reduce ESR of the chip cap, essentially operating as a conditioning process for the device.

[0133] Evaluations of the chip cap 100 have demonstrated superior performance. To provide some context for the evaluation, some terminology is introduced.

[0134] Circuit theory involves ideal resistors, capacitors, and inductors, assuming that each contributes only resistance, capacitance, or inductance to the circuit. However, all components have non-zero values ​​for each of these parameters. In particular, all physical devices are made of materials with finite resistance, so physical components have some resistance in addition to their other properties. The physical source of ESR depends on the device in question.

[0135] In non-electrolytic capacitors and electrolytic capacitors with solid electrolytes, the metal resistance of the leads and electrodes, as well as losses in the dielectric, contribute to the ESR. Typical quoted values ​​for the ESR of ceramic capacitors are between 0.01 and 0.1 ohms. The ESR of non-electrolytic capacitors tends to be fairly stable over time; for most purposes, true non-electrolytic capacitors can be considered ideal components.

[0136] Aluminum and tantalum electrolytic capacitors with non-solid electrolytes have much higher ESR values, up to several ohms. Prior art electrolytic capacitors with higher capacitance have lower ESR. ESR decreases with frequency, up to the self-resonant frequency of the capacitor. A serious problem, especially for aluminum electrolytics, is that ESR increases over time. ESR can increase enough to cause circuit failure or even component damage, even though the measured capacitance may remain within tolerance. Although this occurs with normal aging, high temperatures and large ripple currents exacerbate the problem. In circuits with significant ripple current, an increase in ESR will increase heat dissipation, thereby accelerating aging.

[0137] Electrolytic capacitors rated for high temperature operation and of higher quality than basic consumer-grade parts are less susceptible to becoming prematurely unusable due to increased ESR. An inexpensive electrolytic capacitor may have a rated life of less than 1000 hours at 85°C. Higher grade parts are typically rated for a few thousand hours at the maximum rated temperature. If ESR is critical, a part specification with a higher temperature rating, "low ESR," or greater capacitance than would otherwise be required may be advantageous.

[0138] This type of chip cap in this article shows excellent performance under challenging conditions. In some embodiments, the chip cap may have an operating voltage of at least 2.0V, 2.1V, 2.2V, 2.3V, 2.4V, 2.5V, 3.0V or higher. In some embodiments, the chip cap may have a capacitance of at least 300mF, 400mF, 450mF, 500mF or higher. In some embodiments, the chip cap may have an energy density of at least 4.0J / cc, 4.5J / cc, 5.0J / cc, 5.1J / cc or higher. In some embodiments, the chip cap may have a peak power density of at least 15W / cc, at least 20W / cc, at least 22W / cc or higher. In some embodiments, the device may have an equivalent series resistance of 500mΩ or less, an equivalent series resistance of 400mΩ or less, or an equivalent series resistance of 300mΩ or less. In some embodiments, the device may have an operating temperature rating of at least 65°C, 75°C, 85°C, 100°C, 125°C, 150°C, or higher. Typically, the aforementioned performance parameters can be achieved using a chip cap that accommodates a single energy storage unit. Extended performance (e.g., higher voltage operation) can be achieved by using multiple chip caps and / or chip caps that combine multiple energy storage units.

[0139] In abuse testing, a chip cap of the type described herein can exhibit an operating life of at least 1,000, at least 1,500, or at least 2,000 hours or more at an operating voltage of at least 2.0V or 2.1V or higher (e.g., 2.5V, 3.0V, or higher) and an operating temperature of at least 65°C, 85°C, 100°C, or higher, while exhibiting less than 30% degradation in capacitance and less than 100% increase in equivalent series resistance. In some embodiments, the operating life can begin after the device is soldered to a printed circuit board using a reflow process having at least one, two, three, four, five, six, or more temperature cycles of at least 30 seconds, 60 seconds, 120 seconds, 180 seconds, 240 seconds, 360 seconds, or more, with a peak temperature of at least 100°C, 200°C, 300°C, or higher. Advantageously, the aforementioned abuse test performance levels are expected to correspond to an operating life of much greater than 2,000 hours under non-abuse conditions. For example, in some typical applications (e.g., providing retention power for solid-state drives in enterprise computing environments), the chip cap can have an operating life of 5,000 hours, 7,500 hours, 10,000 hours, 12,500 hours, or more, even under conditions requiring thousands, tens of thousands, hundreds of thousands, or even millions of charge and discharge cycles.

[0140] Figures 14 to 16 Various aspects of the performance of an embodiment of chip cap 100 are depicted. Fig.14 Plotted are ESR performance data for a sample chip cap operating at 85° C. As shown in the graph, after 3800 hours at temperature, the ESR degradation of the chip cap performance was 98%. Fig.15 Comparative data is provided, which shows significantly greater ESR degradation of prior art devices. Fig.16 Additional performance data for chip caps is provided in Fig.16 In the study, after 3800 hours of testing, the capacitance degradation data at 85°C was only 72% of the initial unit performance.

[0141] FIG. 17A to FIG. 17B Various aspects of the performance of an embodiment of chip cap 100 are depicted. Fig.17A The ESR performance data of a sample chip cap operating at 85°C at a voltage of 2.1V is depicted. As shown in the figure, the ESR degradation of the chip cap performance is less than 40% over 2,500 hours at temperature and voltage. Fig. 17B Additional performance data for the chip cap is provided in Fig. 17B In the , the capacitance degradation data at 85°C at a voltage of 2.1 V after 2500 hours of testing is less than 14% of the initial cell performance. Note that the test was conducted after successfully subjecting the chip cap to a solder reflow process.

[0142] FIG. 18A to FIG. 18B Various aspects of the performance of an embodiment of chip cap 100 are depicted. Fig.18A The ESR performance data of a sample chip cap operating at 100°C at a voltage of 2.1V is depicted. As shown in the figure, the ESR degradation of the chip cap performance is less than 65% over 1,500 hours at temperature and voltage. Fig.18B Additional performance data for chip caps is provided in Fig.18B In the , the capacitance degradation data at 100°C at a voltage of 2.1 V after 1500 hours of testing is less than 14% of the initial cell performance. Note that the test was conducted after successfully subjecting the chip cap to a solder reflow process.

[0143] refer to Fig.19, an example of a computing device 500 that can utilize the chip cap 100 is shown. The computing device 500 can be any of a personal computer (PC) 501, a laptop computer 502, a tablet computer 503, a mobile device (such as a smart phone), and a server 505. Other types of computing devices may be included. Examples include controllers for automotive systems as well as industrial systems, residential systems (such as appliances, home electronics, etc.). In short, a computing device utilizing the chip cap 100 can include almost any electronic device that desires board-level power (e.g., a solid-state drive utilized in enterprise computing). In some embodiments, for example, where the chip has an operating temperature rating of 100°C, 125°C, 150°C, or higher, the chip cap can be used in extreme downhole conditions known in the field of oil and gas exploration and production.

[0144] In the illustration shown, chip cap 100 is used to power computer memory 501. Memory 510 may be any type of memory. A power converter and controller suitable for converting power from chip cap 100 are not shown, as such devices are known in the art.

[0145] refer to Fig. 20 , showing a process flow for assembling a chip cap of the type disclosed herein. In step 2001, an electrode roller is provided. The electrode roller can be a double-sided electrode roller having a carbonaceous energy storage medium on opposite sides of a metal foil current collector. In step 2002, a portion of the carbonaceous energy storage medium is removed (e.g., via scraping) to expose the strip of the current collector. In step 2003, the right-hand electrode layer and the left-hand electrode layer are punched or cut from the roller, wherein the conductive lead is formed from the exposed portion of the roller. In step 2004, the punched electrode layers are assembled with separators to form a stack of the type described in detail herein. In step 2005, any excess separators are cut, and the stack is fixed so that the conductive lead extends from the stack. In step 2006, the electrode stack is vacuum dried to remove moisture. In step 2007, the stack is transferred to the open body of the corresponding package. In step 2008, as described in detail herein, an electrical connector is made from the stack to contact the pads in the package. In step 2009, the stack is positioned in a package. In step 2010, electrolyte is dispensed to wet the electrode layers of the stack. In step 2011, a cover is placed on the package. In step 2012, the cover is welded to the package to form a hermetic seal. In step 2013, the completed chip cap is subjected to visual inspection and electrical testing. In step 2014, the chip cap is packaged, for example, by wrapping and rolling the package in a format suitable for pick-and-place mounting techniques familiar in the art.

[0146] Generally, the term "memory" as used herein refers to computer hardware integrated circuits that store information for immediate use in a computer and is synonymous with the term "primary storage." Computer memory, such as random access memory (RAM), operates at high speeds, unlike storage devices that provide slower access speeds but larger capacities.

[0147] The terms "memory", "primary storage", "main memory", "system memory" and other similar terms are often associated with addressable semiconductor memory, i.e., integrated circuits comprising silicon-based transistors, used, for example, as primary storage, but also for other purposes in computers and other digital electronic devices. There are two main types of semiconductor memory: volatile and non-volatile. Examples of non-volatile memory are flash memory (used as secondary storage) and ROM, PROM, EPROM and EEPROM memory (used to store firmware such as BIOS). Examples of volatile memory are main storage, which is typically dynamic random access memory (DRAM), and fast CPU cache memory, which is typically static random access memory (SRAM), which is fast but consumes energy and provides lower memory area density than DRAM.

[0148] Volatile memory is computer memory that requires power to maintain the stored information. Most modern semiconductor volatile memory is static RAM (SRAM) or dynamic RAM (DRAM). SRAM retains its contents as long as the power is on. Dynamic RAM is more complex to interface and control and requires regular refresh cycles to prevent losing its contents.

[0149] Nonvolatile memory is computer memory that retains stored information even when power is not supplied. Examples of nonvolatile memory include read-only memory (see ROM), flash memory, most types of magnetic computer storage devices (e.g., hard drives, floppy disks, and magnetic tape), optical disks, and early computer storage methods such as paper tape and punched cards. Upcoming nonvolatile memory technologies include FeRAM, CBRAM, PRAM, STT-RAM, SONOS, RRAM, racetrack memory, NRAM, 3D XPoint, and millipede memory.

[0150] The third category of memory is "semi-volatile." The term "semi-volatile" generally describes memory that has some limited duration of non-volatility after power is removed, but then the data is eventually lost. The typical goal when using semi-volatile memory is to provide the high performance / endurance, etc. associated with volatile memory, while providing some of the benefits of true non-volatile memory.

[0151] A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit components as memory to store data persistently. SSDs have no moving mechanical parts. This distinguishes them from conventional electromechanical drives (such as hard disk drives (HDDs) or floppy disks), which house a rotating disk and a removable read / write head. Compared to electromechanical drives, SSDs are typically more resistant to physical shock, operate silently, have faster access times, and lower latency.

[0152] As of 2017, most SSDs use NAND-based flash memory, a type of non-volatile memory that retains data when power is lost. For applications that require fast access but do not necessarily require data persistence after power is lost, SSDs can be configured from random access memory (RAM). Such devices may employ a battery as an integrated power source to retain data for a certain amount of time after the loss of external power.

[0153] However, all SSDs still store data in an electrical charge, which will slowly leak out over time if there is no power. This causes worn drives (which exceed their endurance ratings) to typically start losing data after a period of storage. Therefore, current SSDs are not suitable for archival purposes.

[0154] Therefore, by adding an improved power supply, the performance of an SSD can be significantly improved. Most SSDs use capacitors to provide backup power to the DRAM modules to write volatile memory to non-volatile memory. Unfortunately, the available capacitors are large and exhibit low performance.

[0155] In short, the SSD environment presents unique challenges to all capacitive energy storage devices (not just supercapacitor technology). Capacitive storage is used as an on-board power backup to transfer data stored in volatile memory (SRAM / DRAM) to non-volatile memory (NAND, FLASH). This operation is critical to ensure that no data is lost in the event of a power failure. As computational storage becomes increasingly important to almost all business sectors, the need for ultra-reliable memory backup solutions becomes a top priority.

[0156] Having thus described embodiments of an energy storage device for powering an electrical circuit, some additional aspects are now presented.

[0157] Various other components may be included and invoked to provide various aspects of the teachings herein. For example, additional materials, combinations of materials, and / or omissions of materials may be used to provide additional embodiments within the scope of the teachings herein.

[0158] A variety of modifications to the teachings herein may be implemented. Typically, modifications may be designed based on the needs of a user, designer, manufacturer, or other similar interested party. The modifications may be intended to meet specific performance criteria that the party deems important.

[0159] No appended claims or claim elements should be construed as invoking 35 USC §112(f) unless the phrase "means for" or "step for" is expressly used in a particular claim.

[0160] When introducing an element of the present invention or its (one or more) embodiments, the articles "a", "an", and "the" are intended to indicate the presence of one or more elements. Similarly, the adjective "another", when used to introduce an element, is intended to indicate one or more elements. The terms "including" and "having" are intended to be inclusive, so that there may be additional elements in addition to the listed elements. As used herein, the term "exemplary" is not intended to imply a superlative example. Rather, "exemplary" refers to an embodiment that is one of multiple possible embodiments.

[0161] Although the present invention has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present invention. In addition, it will be appreciated by those skilled in the art that a variety of modifications may be made to adapt a particular instrument, situation, or material to the teachings of the present invention without departing from the basic scope of the present invention. Therefore, it is not intended that the present invention be limited to the specific embodiments disclosed as the best mode for carrying out the present invention, but rather that the present invention will include all embodiments falling within the scope of the appended claims.

[0162] The present invention also provides the following technical solutions:

[0163] Note 1. An energy storage device suitable for mounting on a printed circuit board using a solder reflow process, the device comprising:

[0164] a sealed case body including positive and negative internal contacts, each disposed within the body and each in electrical communication with positive and negative external contacts, respectively, each of the external contacts providing electrical communication with an exterior of the body;

[0165] an electric double layer capacitor (EDLC) energy storage cell disposed in a cavity in the body and comprising a stack of alternating electrode layers and electrically insulating separator layers;

[0166] an electrolyte disposed within the cavity and wetting the electrode layer;

[0167] a positive lead electrically connecting a first set of one or more of the electrode layers to the positive internal contact; and

[0168] A negative lead electrically connects a second set of one or more of the electrode layers to the negative internal contact.

[0169] Note 2. The apparatus of Note 1, wherein each of the electrode layers comprises an energy storage medium that is substantially free of a binder and consists essentially of a carbonaceous material.

[0170] Note 3. The apparatus of Note 2, wherein the energy storage medium comprises a carbon nanotube network defining void spaces; and a carbonaceous material located in the void spaces and bounded by the carbon nanotube network.

[0171] Note 4. The device of note 3, wherein at least one electrode layer comprises a double-sided electrode layer having an energy storage medium disposed on opposing surfaces of the conductive current collector layer.

[0172] Note 5. The device according to any of the preceding notes, wherein the surface of the energy storage unit that is in physical contact with the body is composed of an electrically insulating material.

[0173] Note 6. The apparatus of any of the preceding notes, wherein each of the electrode layers comprises a conductive tab attached to one of the positive lead and the negative lead.

[0174] Note 7. The device of any of the preceding notes, comprising an anti-corrosion feature located adjacent one of the internal contacts and configured to limit electrochemical reactions between the internal contact and the electrolyte during operation of the device.

[0175] Note 8. The apparatus of Note 7, wherein:

[0176] The internal contact includes a first material having a relatively high electrochemical activity with the electrolyte;

[0177] The corrosion protection feature includes a protective layer of a second material having a relatively lower electrochemical activity with the electrolyte than the first material, the protective layer being configured to prevent contact between the first material and the electrolyte.

[0178] Note 9. The device of note 8, wherein the protective layer comprises a layer of sealant.

[0179] Note 10. The apparatus of note 8, wherein the protective layer comprises a metal layer disposed on a surface of the first material.

[0180] Supplementary note 11. The device according to supplementary note 8, wherein the protective layer includes a metal layer disposed on a surface of the first material and a sealant layer disposed on the metal layer.

[0181] Note 12. The device according to note 11, wherein a metal gasket is included in the metal layer, the metal gasket covering at least a portion of the internal contact and fixed by the sealant layer.

[0182] Note 13. The apparatus of any of Notes 7 to 12, wherein the interior surface of the body includes a recessed portion configured to receive at least a portion of the corrosion protection feature.

[0183] Note 14. The apparatus of any of Notes 7 to 13, wherein a portion of the positive or negative lead extends through the corrosion resistant feature to connect to one of the internal contacts.

[0184] Note 15. The apparatus of any of Notes 7 to 14, wherein the corrosion resistant feature comprises an aluminum metal layer.

[0185] Note 16. The apparatus of any of Notes 7 to 15, wherein the corrosion protection feature comprises an epoxy sealant.

[0186] Note 17. The apparatus according to any of the preceding notes, further comprising an electrically insulating enclosure barrier enclosing the energy storage unit and the electrolyte, the electrically insulating enclosure barrier being configured to prevent the electrolyte and the energy storage unit from contacting a surface of the cavity.

[0187] Note 18. The apparatus of note 17, wherein the lead extends from the energy storage cell through the barrier to the internal contact.

[0188] Note 19. The apparatus of note 18 wherein the barrier is heat sealed to the lead to prevent leakage of the electrolyte from within the barrier envelope.

[0189] Note 20. A device according to any of the preceding notes, wherein the body is a chip, the chip being configured to be surface mounted on a printed circuit board, wherein when so mounted, the chip extends no more than about 5.0 mm above the major surface of the printed circuit board.

[0190] Note 21. A device according to any of the preceding notes, wherein the body is a chip, the chip being configured to be surface mounted on a printed circuit board, wherein when so mounted, the chip extends no more than about 4.0 mm above the major surface of the printed circuit board.

[0191] Note 22. A device according to any of the preceding notes, wherein the body is a chip, the chip being configured to be surface mounted on a printed circuit board, wherein when so mounted, the chip extends no more than about 3.0 mm above the major surface of the printed circuit board.

[0192] Note 23. A device according to any of the preceding notes having an operating voltage of at least 2.0V.

[0193] Note 24. The device of any of the preceding notes having an operating voltage of at least 2.1V.

[0194] Note 25. A device according to any of the preceding notes having an operating voltage of at least 2.5V.

[0195] Note 26. The device of any of the preceding notes having an operating voltage of at least 3.0V.

[0196] Note 27. A device according to any of the preceding notes, having a capacitance of at least 300 mF.

[0197] Note 28. A device according to any of the preceding notes, having a capacitance of at least 400 mF.

[0198] Note 29. The apparatus of any of the preceding notes having an energy density of at least 4.0 J / cc.

[0199] Note 30. The apparatus of any of the preceding notes having a peak power density of at least 15 W / cc.

[0200] Note 31. The apparatus of any of the preceding notes having a peak power density of at least 20 W / cc.

[0201] Note 32. The apparatus of any of the preceding notes having a peak power density of at least 22 W / cc.

[0202] Note 33. A device according to any of the preceding notes, having an equivalent series resistance of 500 mΩ or less.

[0203] Note 34. A device according to any of the preceding notes, having an equivalent series resistance of 400 mΩ or less.

[0204] Note 35. A device according to any of the preceding notes, having an equivalent series resistance of 300 mΩ or less.

[0205] Note 36. A device according to any of the preceding notes having an operating life of at least 2,000 hours at an operating voltage of at least 2.0 V and an operating temperature of at least 65° C. while exhibiting less than 30% capacitance degradation and less than 100% equivalent series resistance increase.

[0206] Note 37. A device according to any of the preceding notes having an operating life of at least 2,000 hours at an operating voltage of at least 2.0 V and an operating temperature of at least 85° C. while exhibiting less than 30% capacitance degradation and less than 100% equivalent series resistance increase.

[0207] Note 38. A device according to any of the preceding notes having an operating life of at least 2,000 hours at an operating voltage of at least 2.0 V and an operating temperature of at least 100° C. while exhibiting less than 30% capacitance degradation and less than 100% equivalent series resistance increase.

[0208] Note 39. The device of any of Notes 36 to 38, wherein the operational life occurs after the device has been soldered to a printed circuit board using a reflow process having at least one temperature cycle of at least 30 seconds with a peak temperature of at least 200°C.

[0209] Note 40. The device of note 35, wherein the operational life occurs after the device has been soldered to a printed circuit board using a reflow process having at least four temperature cycles, each temperature cycle lasting at least 30 seconds, with a peak temperature of at least 200°C.

[0210] Note 41. The apparatus of any of the preceding notes, wherein the energy storage unit provides backup power to at least one additional component mounted to the circuit board.

[0211] Note 42. The device of any of the preceding notes, wherein the electrolyte comprises an ionic liquid.

[0212] Note 43. The apparatus of note 42, wherein the electrolyte further comprises a salt.

[0213] Note 44. The device of note 42 or 43, wherein the electrolyte further comprises a solvent.

[0214] Note 45. The device according to any of the preceding notes, wherein the housing body is hermetically sealed.

[0215] Note 46. The apparatus of any of the preceding notes, wherein the total concentration of halogen ions within the cavity of the housing body housing the energy storage unit is maintained below about 1,000 ppm.

[0216] Note 47. The apparatus of any of the preceding notes, wherein within the cavity of the housing body housing the energy storage unit, metallic species impurities are maintained below about 1,000 ppm.

[0217] Note 48. The apparatus according to any of the preceding notes, wherein impurities of ethyl bromide, ethyl chloride, 1-bromobutane, 1-chlorobutane, 1-methylimidazole, ethyl acetate and dichloromethane are maintained below about 1,000 ppm within the cavity of the shell body that accommodates the energy storage unit.

[0218] Note 49. The apparatus of any of the preceding notes, wherein moisture within the cavity of the housing body housing the energy storage unit is maintained below about 100 ppm.

[0219] Note 50. The apparatus according to any of the preceding notes, wherein halogen impurities are maintained below about 200 ppm within the cavity of the housing body housing the energy storage unit.

[0220] Note 51. The device according to any of the preceding notes, wherein the device comprises a single energy storage unit housed in the sealed housing body.

[0221] Note 52. The device of any of the preceding notes having an operating temperature of at least 65°C at an operating voltage of 2.1V.

[0222] Note 53. The device of any of the preceding notes having an operating temperature of at least 85°C at an operating voltage of 2.1V.

[0223] Note 54. The device of any of the preceding notes having an operating temperature of at least 100° C. at an operating voltage of 2.1V.

[0224] Note 55. The apparatus of any of the preceding notes, wherein the electrolyte comprises a cation selected from the list consisting of 1-(3-cyanopropyl)-3-methylimidazolium, 1,2-dimethyl-3-propylimidazolium, 1,3-bis(3-cyanopropyl)imidazolium, 1,3-diethoxyimidazolium, 1-butyl-1-methylpiperidinium, 1-butyl-2,3-dimethylimidazolium, 1-butyl-3-methylimidazolium, 1-butyl-4-methylpyridinium, 1-butylpyridinium, 1-decyl-3-methylimidazolium, 1-ethyl-3-methylimidazolium, 3-methyl-1-propylpyridinium, and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide.

[0225] Note 56. An apparatus according to any of the preceding notes, wherein the electrolyte comprises an anion selected from the list consisting of bis(trifluoromethanesulfonate)imide, tris(trifluoromethanesulfonate)methide, dicyanamide, tetrafluoroborate, hexafluorophosphate, trifluoromethanesulfonate, bis(pentafluoroethanesulfonate)imide, thiocyanate, trifluoro(trifluoromethyl)borate, spiro-(1,1′)-bipyrrolidinium tetrafluoroborate, another potential salt is tetraethylammonium tetrafluoroborate, and combinations thereof, and other equivalents deemed appropriate.

[0226] Note 57. The apparatus of any of the preceding notes, wherein the electrolyte comprises a solvent selected from the list consisting of acetonitrile, amides, benzonitrile, butyrolactone, cyclic ethers, dibutyl carbonate, diethyl carbonate, diethyl ether, dimethoxyethane, dimethyl carbonate, dimethylformamide, dimethyl sulfone, dioxane, dioxolane, ethyl formate, ethylene carbonate, ethyl methyl carbonate, lactones, linear ethers, methyl formate, methyl propionate, methyltetrahydrofuran, nitrile, nitrobenzene, nitromethane, n-methylpyrrolidone, propylene carbonate, cyclopentane, sulfone, tetrahydrofuran, tetramethylene sulfone, thiophene, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, carbonates, gamma-butyrolactone, nitrile, tricyanohexane, butyronitrile, ethylene carbonate, and dichloromethane.

[0227] Note 58. The device of any of the preceding notes, wherein the electrolyte comprises a gel.

[0228] Note 59. The apparatus of any of the preceding notes, wherein the electrolyte comprises a solid electrolyte.

[0229] Note 60. An apparatus according to any of the preceding notes, wherein the stack accommodates unequal numbers of positive electrode layers and negative electrode layers, and the positive electrode layers and the negative electrode layers are configured to promote mass balance of the stack based on the relative sizes of cations and anions in the electrolyte.

[0230] Note 61. A method of manufacturing an energy storage device suitable for mounting on a printed circuit board using a solder reflow process, the method comprising:

[0231] forming an electric double layer capacitor (EDLC) energy storage cell comprising a stack of alternating electrode layers and electrically insulating separator layers;

[0232] The energy storage unit is disposed in a shell body, wherein the body includes a positive electrode internal contact and a negative electrode internal contact disposed in the body;

[0233] at least partially filling the body with an electrolyte to wet the electrode layer;

[0234] electrically connecting a positive lead from a first set of one or more of the electrode layers to the positive internal contact;

[0235] electrically connecting a negative lead from a second set of one or more of the electrode layers to the negative internal contact; and

[0236] The housing body is sealed, wherein the energy storage unit is disposed therein.

[0237] Note 62. The method of note 61, wherein sealing the shell body comprises hermetically sealing the shell body.

[0238] Note 63. A method of providing energy to a device mounted on a printed circuit board, the method comprising:

[0239] mounting the device of any one of Notes 1 to 60 to the printed circuit board using a solder reflow process; and

[0240] repeatedly charging and discharging the device at an operating voltage and an operating temperature to provide energy to the apparatus;

[0241] wherein the operating voltage is at least 2V and the operating temperature is at least 65°C.

[0242] Note 64. The method of note 63, wherein the operating temperature is at least 85°C.

[0243] Note 65. The method of any of Notes 63 to 64, comprising repeatedly charging and discharging the device at an operating voltage and operating temperature to provide energy to the device for at least 2,000 hours while the device exhibits less than 30% degradation in capacitance and less than 100% increase in equivalent series resistance.

Claims

1. An energy storage device suitable for mounting on a printed circuit board using a solder reflow process, the device comprising: a sealed case body including positive and negative internal contacts, each disposed within the body and each in electrical communication with positive and negative external contacts, respectively, each of the external contacts providing electrical communication with an exterior of the body; an electric double layer capacitor (EDLC) energy storage cell disposed within a cavity in the body and comprising a stack of alternating electrode layers and electrically insulating separator layers; an electrolyte disposed within the cavity and wetting the electrode layer; a positive lead electrically connecting a first set of one or more of the electrode layers to the positive internal contact; and A negative lead electrically connects a second set of one or more of the electrode layers to the negative internal contact; wherein each of the electrode layers comprises an energy storage medium comprising a carbonaceous material disposed in void spaces defined by a carbon nanotube network.

2. The device of claim 1, wherein at least one electrode layer comprises a double-sided electrode layer having an energy storage medium disposed on opposite surfaces of a conductive current collector layer.

3. The apparatus of claim 1, wherein a surface of the energy storage cell that is in physical contact with the sealed housing body comprises an electrically insulating material. 4 . The apparatus of claim 1 , wherein each of the electrode layers comprises a conductive tab attached to one of the positive lead and the negative lead.

5. The device of claim 1, further comprising an anti-corrosion feature located proximate one of the internal contacts and configured to limit an electrochemical reaction between the internal contact and the electrolyte during operation of the device.

6. The apparatus according to claim 5, wherein: The internal contact includes a first material having a relatively high electrochemical activity with the electrolyte; The corrosion protection feature includes a protective layer of a second material having a relatively lower electrochemical activity with the electrolyte than the first material, the protective layer being configured to prevent contact between the first material and the electrolyte. The device of claim 6 , wherein the protective layer comprises a sealant layer.

8. The apparatus of claim 6, wherein the protective layer comprises a metal layer disposed on a surface of the first material. 9 . The apparatus of claim 6 , wherein the protective layer comprises a metal layer disposed on a surface of the first material and a sealant layer disposed on the metal layer. 10 . The device of claim 9 , wherein a metal gasket is included in the metal layer, the metal gasket covering at least a portion of the inner contact and secured by the sealant layer.

11. The apparatus of claim 5, wherein an interior surface of the body includes a recessed portion configured to receive at least a portion of the corrosion protection feature.

12. The apparatus of claim 5, wherein a portion of the positive or negative lead extends through the corrosion resistant feature to connect to one of the internal contacts.

13. The apparatus of claim 5, wherein the corrosion resistant feature comprises an aluminum metal layer.

14. The apparatus of claim 5, wherein the corrosion resistant feature comprises an epoxy sealant.

15. A method of manufacturing an energy storage device suitable for mounting on a printed circuit board using a solder reflow process, the method comprising: forming an electric double layer capacitor (EDLC) energy storage cell comprising a stack of alternating electrode layers and electrically insulating separator layers; The energy storage unit is disposed in a shell body, wherein the body includes a positive electrode internal contact and a negative electrode internal contact disposed in the body; at least partially filling the body with an electrolyte to wet the electrode layer; electrically connecting a positive lead from a first set of one or more of the electrode layers to the positive internal contact; electrically connecting a negative lead from a second set of one or more of the electrode layers to the negative internal contact; wherein each of the electrode layers comprises an energy storage medium comprising a carbonaceous material disposed in void spaces defined by a carbon nanotube network; and The housing body in which the energy storage unit is disposed is sealed. The method of claim 15 , wherein sealing the housing body comprises hermetically sealing the housing body.

17. A method of providing energy to a device mounted on a printed circuit board, the method comprising: mounting the device of claim 1 to the printed circuit board using a solder reflow process; as well as repeatedly charging and discharging the device at an operating voltage and an operating temperature to provide energy to the apparatus; wherein the operating voltage is at least 2V and the operating temperature is at least 65°C.

18. The method of claim 17, comprising repeatedly charging and discharging the device at an operating voltage and operating temperature to provide energy to the device for at least 2,000 hours while the device exhibits less than 30% capacitance degradation and less than 100% equivalent series resistance increase.

19. An energy storage device suitable for mounting on a printed circuit board using a solder reflow process, the device comprising: a sealed case body including positive and negative internal contacts, each disposed within the body and each in electrical communication with positive and negative external contacts, respectively, each of the external contacts providing electrical communication with an exterior of the body; an electric double layer capacitor (EDLC) energy storage cell disposed within a cavity in the body, comprising a stack of alternating electrode layers and electrically insulating separator layers; wherein each of the electrode layers comprises an energy storage medium comprising a carbonaceous material disposed in void spaces defined by a carbon nanotube network; an electrolyte disposed within the cavity and wetting the electrode layer; a positive lead electrically connecting a first set of one or more of the electrode layers to the positive internal contact; a negative lead electrically connecting a second set of one or more of the electrode layers to the negative internal contact; as well as An anti-corrosion feature is located adjacent one of the internal contacts and is configured to limit an electrochemical reaction between the internal contact and the electrolyte during operation of the device.

20. The apparatus of claim 19, wherein: The internal contact includes a first material having a relatively high electrochemical activity with the electrolyte; The corrosion protection feature includes a protective layer of a second material having a relatively lower electrochemical activity with the electrolyte than the first material, the protective layer being configured to prevent contact between the first material and the electrolyte.

Images