ENERGY STORAGE DEVICE HAVING CELL WITH COATING

An energy storage device including an energy storage cell having a metal substrate or a metal sleeve. The energy storage cell includes a coating disposed on the metal substrate or metal sleeve, wherein the coating includes one of an electrolytic deposited coating, an electroless deposited coating, or an applied coating. The coating is electrically non-conductive but thermally conductive. The coated energy storage cell include an exposed positive electrode, an exposed negative electrode. A plurality of energy storage cells is located in a block having a plurality of compartments, wherein one cell of each of the plurality of energy storage cells is disposed in one of the plurality of compartments to provide an energy storage module.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to an energy storage device and more particularly to an energy storage device for an electric vehicle including a plurality of energy storage cells.

BACKGROUND

Energy storage devices, such as electric batteries in electric vehicles, may utilize active heating and/or active cooling based on desired charge and discharge currents for vehicle needs.

SUMMARY

According to an aspect of the present disclosure, an energy storage device includes at least one energy storage cell with a coating. In embodiments, the coating is an epoxy or other material coating or the coating is a modified metal surface, such as through passivation in a non-limiting example.

In one embodiment, there is provided an energy storage device including an energy storage cell including a metal substrate or a metal sleeve, wherein the energy storage cell includes a coating disposed on the metal substrate or metal sleeve, wherein the coating includes one of an electrolytic deposited coating, an electroless deposited coating, or an applied coating.

In some implementations, the energy storage device includes wherein the one of the electrolytic deposited coating, the electroless deposited coating, or the applied coating comprises a non-conductive but thermally conductive coating.

In some implementations, the energy storage device includes wherein the applied coating includes a metal sleeve, an epoxy polymer, or a ceramic coating.

In some implementations, the energy storage device includes wherein the applied coating includes a thickness of between one-tenth of a millimeter and one millimeter.

In some implementations, the energy storage device includes wherein the one of the electrolytic deposited coating or the electroless deposited coating comprises a passivation layer.

In some implementations, the energy storage device includes wherein the energy storage cell includes a positive electrode and a negative electrode, wherein the positive electrode and the negative electrode are free of passivation film.

In some implementations, the energy storage device includes wherein the passivation layer includes a thickness of between five nanometers and fifty nanometers.

In some implementations, the energy storage device includes wherein the passivation layer of the electrolytic deposited coating results from an exposure to an electrolyte.

In some implementations, the energy storage device includes wherein the passivation layer of the electrolytic deposited coating results from chemical reduction of metal ions in an aqueous solution.

In another embodiment, there is provided a method of preparing a battery cell for use in an energy storage module having a hollow block. The method includes: identifying a type of metal of a metal substrate or a metal sleeve of the battery cell; identifying a first location of a positive electrode; identifying a second location of a negative electrode; masking the first location of the positive electrode with a first mask; masking the second location of the negative electrode with a second mask; placing the battery cell in one of an electrolyte bath or an anodizing bath; immersing the battery cell in the one of the electrolyte bath or the anodizing bath to apply an electrically non-conductive but thermally conductive film layer of a predetermined thickness to the metal; removing the battery cell from the one of the electrolyte bath or the anodizing bath after the film layer includes the predetermined thickness; and removing the first mask from the positive electrode and the second mask from the negative electrode.

In some implementations, the method includes wherein the predetermined thickness is between five nanometers and fifty nanometers.

In some implementations, the method includes wherein the immersing the battery includes immersing the battery cell for a predetermined period of time to apply the film layer of the predetermined thickness.

In some implementations, the method includes wherein the predetermined period of time is based on the type of metal or the kind of the one of the electrolyte bath or the anodizing bath.

In some implementations, the method further includes exposing the metal located beneath the film layer to provide one of an electrically conductive site or an electrical welding site.

In some implementations, the method further includes agitating the one of the electrolyte bath or the anodizing bath while immersing the battery cell.

In some implementations, the method includes wherein the electrolyte bath includes a nitric acid solution.

In a further embodiment, there is provided an energy storage module including a plurality of battery cells, wherein each of the battery cells includes metal substrate, an exposed positive electrode, an exposed negative electrode, and a coating disposed on the metal substrate, wherein the coating comprises a non-conductive but thermally conductive coating. The module includes a block including a plurality of compartments, wherein one battery cell of each of the plurality of battery cells is disposed in one of the plurality of compartments.

In some implementations, the energy storage module includes wherein each of the plurality of battery cells includes one of an electrolytic deposited coating, an electroless deposited coating, or an applied coating.

In some implementations, the energy storage module includes wherein the plurality of compartments are fluidically coupled to transfer an electrically conductive fluid between each of the plurality of compartments.

In some implementations, the energy storage device includes wherein the plurality of compartments is configured to prevent the exposed positive electrode and the exposed negative electrode from being fluidically coupled to the electrically conductive fluid.

Other features and aspects will become apparent by consideration of the detailed description, claims, and accompanying drawings.

Like reference numerals are used to indicate like elements throughout the several figures.

DETAILED DESCRIPTION

The present disclosure relates to cylindrical, pouch or prismatic cell batteries that use metal housings, sleeves, or both, designed to be electrically insulative, but thermally conductive, which can be used to prevent electrical conduction between the housing and a conductive cooling medium, such as a cooling liquid having conductive properties. Once such cooling liquid having conductive properties include oil. The electrically insulted cell batteries prevent arc propagation during a battery short, but enable efficient cooling of the cells using versatile coolant fluid options seen in the marketplace. The present disclosure provides a battery including a metal housing or sleeve material that is used for making cylindrical, prismatic or pouch form factors that are electrically insulative, but thermally conductive, such as for use in immersion cooled batteries in a non-limiting example. This metal substrate can be made of any suitable metals such as stainless steel or aluminum and treated during roll production, during roll manufacturing, or after roll manufacture to achieve the desired electrical and thermal properties. The metal substrate may be formed as a separate sleeve or casing around the cell or directly on the outer surface of the cell.

The metal substrate material can be treated in various ways to create an electrically insulative, but thermally conductive surface. For example, the metal canister material used in cylindrical cells can be passivated to create a surface layer that is electrically insulative but thermally conductive. The process of creating a passivation layer can be done electrolytically or via electroless process. The passivation process can be performed by exposing the metal substrate to a solution of nitric acid and sodium dichromate, among other electrolytes. The nature of these electrolytes will vary depending on the metal that is being treated. These electrolytes could be such strong acids as sulfuric acid, hydrochloric acid, or hydrofluoric acid, to name some non-limiting examples, or could be strong base materials or liquids as well. The thickness of the passivation layer can be between five (5) and fifty (50) nanometers and may be generally self-limiting due to losing electrical conductivity at the surface.

These layers can also be controlled with electrical current pulse parameters such as frequency, magnitude, and duration and could be anodic or cathodic. If done with electroless techniques, the layer can be controlled through optimization of electrolyte immersion duration. Since these passivation layers may be thin, a layer may be scratched off or otherwise selectively removed during manufacturing, if there is a desire to have localized conductive spots on the metal, such as for the purposes of improving electrical welding or creating necessary electrical pathways. Alternatively, the metal substrate can be coated with one or more thermally conductive, but electrically insulative materials, such as an epoxy polymer (with high dielectric properties) and/or a ceramic coating.

The coating can be applied using any suitable methods such as powder coating, dip coating, chemical vapor deposition (CVD) or electroplating. The metal prepared in this way can be used in any battery form factors and sizes such as cylindrical, prismatic or pouch cells and can be used for any electrode/electrolyte chemistries such as Lithium ion, Nickel cadmium, or Nickel metal hydride.

The metal sleeve, the coating, or both the metal sleeve and coating can be of any thickness optimized for the application to which the battery cells experience. In a non-limiting example, for instance, the thickness is in the range of one tenth (0.1) and one (1) millimeter.

FIG.1illustrates an energy storage cell10, for example a battery cell of the prior art. The cell10includes generally cylindrical shape having an outer surface defined by a metal substrate12, such as a metal sleeve. The metal sleeve12defines a cylindrical body having a positive electrode14located at a first end16of the cell10and a negative electrode18located at a second end20.

As illustrated inFIG.2, the metal sleeve12is generally rectangular in shape and includes dimensions configured to sufficiently cover the battery components located within the metal sleeve12once the cell10is formed, as is understood by one skilled in the art. The metal sleeve12includes an untreated preformed cylindrical cell, a sleeve, or a metal, which could be aluminum-based, stainless steel, or another metal in certain embodiments, each of which are electrically conductive. For instance,FIG.2illustrates any metal foil, sheet, or roll that is not passivated or otherwise treated to be electrically non-conductive.

FIG.3illustrates the battery cell10being prepared to apply a non-conductive coating to the metal sleeve12. To prevent the metal sleeve12from conducting electricity, a non-conductive coating is applied to the metal sleeve. To insure that the positive electrode14and negative electrode18remain exposed for electrically conductivity, the positive electrode14is covered with a mask22and the negative electrode18is covered with a mask24. Each of the masks22and24is used as a cover to isolate the electrodes14and18from coming into contact with a non-conductive material that is applied to or is deposited on the metal sleeve12. The masks prevent the electrodes from becoming non-conductive.

In one embodiment, the masks22and24include an adhesive tape26applied to the exposed conductive material of the electrodes. Once the non-conductive material is applied to the sleeve12, the adhesive tape is removed. In other embodiments, the masks24include a liquid adhesive applied by a brush or other applicator to the electrodes to form a removable film. In different embodiments, the applied masks cover an entirety of the electrodes or only a portion of the electrodes. If only a portion of the electrodes is covered with the mask, the masked portion includes a portion sufficient to accept an electrical connection or connector once the mask is removed. For instance, the exposed portion is localized, but is sufficiently large enough to accept a welded connection for instance.FIG.4illustrates the application of the adhesive tape26to the positive electrode14which can be peeled from the electrode when required.

FIG.5illustrates a bath30for treating the substrate12of cell10to apply a non-conductive coating or film to the metal. The bath30includes a container32configured to hold a fluid34. In different embodiments, the fluid is an aqueous electrolyte fluid, including water, or a non-aqueous electrolyte fluid, including an acid. In a non-limiting example, the fluid is a nitric acid or citric acid fluid having a temperature of around 40 degrees Centigrade.

Each of the energy storage cells10is immersed in the bath30for a predetermined period of time which is sufficient for the metal to oxidize and to form a layer of non-conductive film on the metal substrate12. The cells10, in one non-limiting example, are placed in the bath and remain there for between five-tenths (0.5) and three (3) hours for stainless steel-based metal housings. The type of electrolyte bath may vary based on the metal being treated. In one non-limiting example, the bath includes a citric acid solution with water at four (4) % to ten (10) %. In some embodiments, the fluid34is agitated continuously with an agitator36. In embodiments using nitric acid, a trial may be conducted to include water from five (5) % to fifty (50) % due to more hazardous conditions and/or handling precautions. In some embodiments, the process could be made electrolytically as well, such as in a typical anodization process. In other embodiments, the fluid34may be altered for surface treatment of aluminum and/or in an anodization process. In other embodiments, the substrate12is immersed in the bath30prior to being used in the manufacture of a completed energy storage cell10. In additional embodiments, the substrate12may be in the form of a strip of material, a coil of material, or other form, that once oxidized, is used to manufacture the energy storage cell10. While a submersible bath30is illustrated, other embodiments include submersible baths that receive energy storage cells10that are suspended from a moving track and which move through the bath from an entry point to an exit point.

FIG.6illustrates a coated energy storage cell40having a coating resulting from the bath process ofFIG.5. Once the passivated or otherwise treated energy storage cell40has been treated, the cylindrical cell, the sleeve, the metal foil, the sheet, or roll, includes a layer of oxidized material which is located on the aluminum, the stainless steel, and/or other metal material used in the energy cells embodiments. The masks22and24are removed for necessary or beneficial connections. As illustrated inFIG.7and as shown by a cross-hatching, a blue or other color passivating film that is electrically non-conductive, but thermally conductive, is formed on the cell, metal, and/or sleeve41. The film provides the electrical characteristics necessary to prevent electrical arc propagation from the energy storage cells and enables the use of electrically conductive fluid without creating an electrical short or generating unacceptable additional weight into the energy storage cells10, therefore keeping within any kilowatt-hours (kWh)/gram metric target.

FIG.8illustrates an energy storage module42that includes a base44having a plurality of compartments, each of which receives a single energy storage cell40which has a metal surface that has been coated with the electrically non-conducting but thermally conducting exterior surface. Once each one of a plurality of the energy storage cells30is placed in one of the plurality of compartments, a cap46is coupled to the cell40to provide an electrical connection to charge or to discharge energy to or from each of the cells40. A fluid source, not shown, is coupled to an inlet of the base44which receives the electrically conductive cooling fluid to insure a proper operating temperature of the energy storage module42. The base44includes an outlet, not shown, which transfers the cooling fluid past each of the plurality of energy storage cells from the inlet to the outlet. The temperature of the fluid is heated or cooled to maintain a predetermined operating temperature of the cells. The fluid is cooled or heated as necessary and returned to the inlet to provide a cooling effect to the energy storage cells.

Without in any way limiting the scope, interpretation, or application of the claims appearing below, a technical effect of one or more of the example embodiments disclosed herein is providing a cell and/or energy storage device that is electrically insulative but thermally conductive surfaces to enable the use of any kind of cooling fluid in larger battery modules or packs including a plurality of modules. The cooling fluid can be conductive or non-conductive or any viscosity most suitable for the application. Non-limiting examples of some conductive coolants are water, aqueous glycol, or oil-based liquids. The unique property of the coated metal prevents electrical arching and propagation during a battery short and ensures safe and efficient cooling of the battery pack. Manufacturing processes can be optimized such that the coated passivation layer can be scratched off using lasers or ultrasonic methods to provide one or more localized conductive spots for the purpose of necessary electrical pathways and for welding. In another embodiment, the metal surface can be prepared in upstream manufacturing processes before a battery specific form factor is stamped for jelly roll insertion.

As used herein, “e.g.” is utilized to non-exhaustively list examples and carries the same meaning as alternative illustrative phrases such as “including,” “including, but not limited to,” and “including without limitation.” Unless otherwise limited or modified, lists with elements that are separated by conjunctive terms (e.g., “and”) and that are also preceded by the phrase “one or more of” or “at least one of” indicate configurations or arrangements that potentially include individual elements of the list, or any combination thereof. For example, “at least one of A, B, and C” or “one or more of A, B, and C” indicates the possibilities of only A, only B, only C, or any combination of two or more of A, B, and C (e.g., A and B; B and C; A and C; or A, B, and C).

Terms of degree, such as “generally”, “substantially” or “approximately” are understood by those of ordinary skill to refer to reasonable ranges outside of a given value or orientation, for example, general tolerances or positional relationships associated with manufacturing, assembly, and use of the described embodiments.

While the above describes example embodiments of the present disclosure, these descriptions should not be viewed in a limiting sense. Rather, other variations and modifications may be made without departing from the scope and spirit of the present disclosure as defined in the appended claims.