DESC:FIELD OF THE INVENTION
[0001] The present invention relates to a supercapacitor modules for two-wheeler electric vehicles. Specifically, the invention relates to a supercapacitor module to be used in for two-wheeler electric vehicles and having supercapacitor unit cells fabricated using graphene-polyaniline nanocomposites.

BACKGROUND OF THE INVENTION
[0002] Electric vehicles are currently in wide use. Electric vehicles generally use a battery as a power source. The battery requires significant time to recharge due to the physical and chemical properties of batteries. Further, delivering both accelerating power and long travel ranges on a single charge requires complicated electronic arrangements and systems.
[0003] Current, normally used, battery technology employs advanced primary and secondary battery architecture to achieve accelerating power, extended single charge travel distances, and improve cycle lifetime of the power pack. One of the biggest challenges of existing electric vehicles is shortage of range, limited to the battery capacity. In addition, present electric vehicles suffer from the slow recharging rate of batteries. Electric vehicles generally require several hours to recharge. Issues related to power density, internal resistance, and thermal management systems in lithium cells also present. Alternative arrangements such as using higher voltages to reduce charging time also exist, however significant reduction in the lifespan of batteries may be another challenge here to overcome. Therefore, it is desirable to use a capacitive energy storage module capable of high-power density and high energy density.
[0004] A supercapacitor is a high-capacity capacitor with a capacitance value much higher than other capacitors, but with lower voltage limits, that bridges the gap between electrolytic capacitors and rechargeable batteries. Supercapacitors are also known as ultracapacitors and typically store 10 to 100 times more energy per unit volume than electrolytic capacitors. Supercapacitors can accept and deliver charge much faster than batteries and tolerate many more charge and discharge cycles than rechargeable batteries. High specific area, mechanical and chemical stability and low cost are often required for supercapacitor materials.
[0005] Various prior art methods have been used to fabricate supercapacitor devices using composite materials. These supercapacitor devices produced are not capable enough to withstand high voltage. Moreover, their production cost is also on the higher side and their scalability in industry is currently narrowing the application options because energy efficiency is negated against cost efficiency.
SUMMARY OF THE INVENTION
[0006] This summary is provided to introduce a selection of concepts in a simple manner that is further described in the detailed description of the disclosure. This summary is not intended to identify key or essential inventive concepts of the subject matter nor is it intended for determining the scope of the disclosure.
[0007] The present disclosure relates to designing and fabrication of graphene and polyaniline nanocomposite electrodes (alternately, nanotrodes) based supercapacitor unit cells and construction of supercapacitors modules for two-wheeler electric vehicles using the supercapacitor unit cells. The supercapacitor unit cells include two identical nanotrodes and an aqueous inorganic acid-based electrolyte and a suitable polyethylene (PE) membrane separator.
[0008] The disclosure also includes development and assembling of the supercapacitor modules for using in two-wheeler electric vehicles. The development of supercapacitor module includes development of supercapacitor unit cells having nanotrodes, electrolytes and the separator.
[0009] In one aspect, the present disclosure relates to a supercapacitor module for two-wheeler electric vehicles. The supercapacitor module includes a plurality of supercapacitor units. Each supercapacitor unit includes two identical electrodes having graphene-polyaniline nanocomposites, an electrolyte having an aqueous inorganic acid, and a polyethylene membrane separator.
[0010] In another aspect, the present disclosure relates to a process for forming a supercapacitor module for two-wheeler electric vehicles. The process includes assembling 12 supercapacitor units in series. A fabrication process of a supercapacitor unit includes the steps of forming and assembling two identical electrodes comprising graphene-polyaniline nanocomposites, forming an electrolyte comprising an aqueous inorganic acid and disposing the electrolyte in between the two electrodes, and forming a polyethylene membrane separator and disposing the separator in between the two electrodes.
[0011] Further advantages and other details of the present subject matter will be apparent from a reading of the following description and a review of the associated drawings. It is to be understood that the following description is explanatory only and is not restrictive of the present disclosure.
BRIEF DESCRIPTION OF THE FIGURES
[0012] These and other features, aspects, and advantages of the exemplary embodiments can be better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
[0013] FIG. 1 illustrates a schematic representation of integration of a supercapacitor module in a two-wheeler electric vehicle, in accordance with an embodiment of the present disclosure;
[0014] FIG. 2 shows a circuit design of a supercapacitor module that can be used in a two-wheeler electric vehicle, in accordance with an embodiment of the present disclosure;
[0015] FIG. 3 shows a schematic diagram illustrating a process of forming a supercapacitor module, in accordance with an embodiment of the present disclosure;
[0016] Figure 4 shows a fabrication process of forming a supercapacitor unit, in accordance with an embodiment of the present disclosure; and
[0017] Figure 5A and 5B show the analysis of supercapacitor modules, in accordance with an embodiment of the present disclosure.
[0018] It may be noted that to the extent possible like reference numerals have been used to represent like elements in the drawings. Further, those of ordinary skilled in the art will appreciate that elements in the drawings are illustrated for simplicity and may not have been necessarily drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help to improve understanding of aspects of the disclosure. Furthermore, the one or more elements may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the disclosure so as not to obscure the drawings with details that will be readily apparent to those of ordinary skilled in the art having the benefits of the description herein.
DETAILED DESCRIPTION OF THE INVENTION:
[0019] For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Such alterations and further modifications to the disclosure, and such further applications of the principles of the disclosure as described herein being contemplated as would normally occur to one skilled in the art to which the disclosure relates are deemed to be a part of this disclosure.
[0020] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the disclosure and are not intended to be restrictive thereof.
[0021] In the present disclosure, relational terms such as first and second, and the like, may be used to distinguish one entity from the other, without necessarily implying any actual relationship or order between such entities.
[0022] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or a method. Similarly, one or more elements or structures or components preceded by "comprises... a" does not, without more constraints, preclude the existence of other elements, other structures, other components, additional devices, additional elements, additional structures, or additional components. Appearances of the phrase “in an embodiment”, “in another embodiment” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.
[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The components, methods, and examples provided herein are illustrative only and not intended to be limiting.
[0024] In some embodiments, the invention disclosed here involves a supercapacitor module configured to be used with a two-wheeler electric vehicle (EV). The supercapacitor may be used in the EV, as a stand alone energy provider or along with one or more EV battery packs.
[0025] Figure 1 illustrates a two-wheeler electric vehicle 10 with a supercapacitor module 100 and a battery system 110. The supercapacitor module 100 and the battery 110 together take care of energy management needs of the electric vehicle 10. In accordance with embodiment of the present disclosure, the supercapacitor module 100 has a plurality of supercapacitor units 110, as shown in Figure 2. In some embodiments, the supercapacitor module 100 used in the electric vehicle 10 has 12 supercapacitor units 110. Each supercapacitor unit 110 may include two identical electrodes 112 (shown in Figure 3) an electrolyte (not shown) and a separator 114. The two identical electrodes 112 may have graphene-polyaniline based nanocomposites, the electrolyte may have an aqueous inorganic acid, and the separator 114 has a polyethylene membrane.
[0026] The schematic image of two-wheeler electric vehicle supercapacitor module 100 shown in figure 2 has 12 supercapacitor units 110 with series connection to achieve the energy need of the two-wheeler electric vehicle 10. In some embodiments, the supercapacitor unit cells 110 are connected in parallel configuration to form the supercapacitor module 100. Any dimension of the supercapacitor unit 110 may be used. In some embodiments, the supercapacitor module 100 includes 12 supercapacitor units 110 with dimensions of 12.5 cm X 12.5 cm X 2 cm.
[0027] A process of forming the supercapacitor module includes assembling of two electrodes 112 in a unit cell 110 of a supercapacitor. The graphene - polyaniline based nanocomposite may alternately referred as a “nanotrode”. The electrode morphology has graphene sheet structures with polyaniline fibers. In the nanotrodes, both the graphene and polyaniline are in the nano size having length dimensions in a range from around 20 nm to 50 nm. In some embodiments, the two electrodes i.e., nanotrodes used herein are identical. As used herein, the identical electrodes have the same composition, dimension, design, porosity, surface area etc.
[0028] The development of the nanotrode relates to designing the thickness of the nanotrode, magnitude of graphene - polyaniline polymer composite coating on the nanotrode, the loading percentage of graphene in the nanocomposite, the loading percentage of polymer, the type of graphene and the nanocomposite process parameters. A typical process for nanotrode preparation and designing may be as disclosed in the US patent number 16055195. In some embodiments, the two electrodes individually have a thickness in a range from 0.1 mm to 2mm. In some embodiments, the graphene - polymer composite electrodes (nanotrode technology-based electrodes) have high surface area and tunable porosity.
[0029] Aqueous inorganic electrolytes are developed to meet the required properties of super capacitor cell 110. In some embodiments, an aqueous inorganic electrolyte that can be used along with the nanotrode technology-based electrodes in the unit cell of the supercapacitor involves designing concentration of inorganic acid in the aqueous solution and specific preparation process parameters such as temperature and mixing time.
[0030] In some embodiments, the aqueous inorganic electrolyte includes one or more acids. In some embodiments, a concentration of acid in the aqueous solution is in a range from 0.1 molar to 1 molar. In some embodiments, the aqueous acid in the electrolyte includes 0.1 molar to 1 molar PVA gelled H2SO4. In some embodiments, forming the electrolyte includes dissolving H2SO4 in Poly Vinyl Alcohol (PVA) in a concentration in a range from 0.1 molar to 1 molar at a temperature in a range from 60 degrees Celsius to 70 degree Celsius along with stirring. The aqueous inorganic electrolyte has good ionic conductivity. In some embodiments, the ionic conductivity of the aqueous inorganic electrolyte is in a range from 1 to 5 S-cm2.
[0031] In some embodiments, a separator is developed to be used in the unit cell. The developed separator has specification such that the type of separator, thickness and porosity of the separator works well with the selected electrodes and the electrolyte. In some embodiments, polyethylene battery grade separators are used in the supercapacitor unit. In some embodiments, the separator has a thickness in a range from 0.1 mm to 1mm.
[0032] In some embodiments, development of a fabrication process 300 for the supercapacitor modules 100 is disclosed. Figure 3 illustrates a schematic diagram of the fabrication process of the supercapacitor module 100 and figure 4 illustrates an example fabrication process of the supercapacitor unit 110. In a first step of the process 300, the electrodes 112, electrolyte and the separator 114 are formed and the assembly of these constituents for fabricating the supercapacitor unit 110 is carried out in a second step of the process 300. The supercapacitor module is formed by assembling the units 110 in the third step and sealed to obtain the supercapacitor module in the 4th step. In some embodiments, the assembling of supercapacitor units 110 includes a process of pouch making and sealing under dry atmosphere. The process parameters are developed to enhance final performance of the unit supercapacitor. The fabrication process 400 of the supercapacitor unit 110 includes the steps of preparing the electrolyte gel and coating the electrodes with the electrolyte gel as shown in figure 4. In some embodiments, forming a polyethylene membrane separator includes the step of coating a polyethylene membrane with PVA gelled electrolyte and drying in vacuum. The separator 114 is placed between the electrolyte coated electrodes and the current collectors are attached to the electrolyte coated electrodes to form the unit cell 110.
[0033] Further, the present disclosure includes method of development of supercapacitor packs based on the voltage and power demands of a two-wheeler electric vehicle and integration of supercapacitor packs for the two-wheeler electric vehicle and it’s testing to increase the performance of the existing battery packs by tuning the required voltage and power density.
[0034] In some embodiments, the supercapacitor module 100 has a voltage of 12 volts, capacitance of 200F, energy of 4.3Wh, power of 3kw, and weight of 1.15 kilograms. These may be packed in a pouch having dimensions of 25 cm X 5 cm X 15 cm.
[0035] A number of iterations are carried out to check the performance and to obtain parameters to attempt the final commercialization of supercapacitor prototypes and its specifications. The iterations include assembling and fabrication of different capacities of supercapacitors, optimization of electrolytes and its testing.
[0036] Analyses of an example supercapacitor module 100 is shown in figure 5. Figure 5A illustrates a cyclic voltammetry graph of the module. This curve shows good capacity and high energy storage ability of supercapacitor modules 100. Figure 5B illustrates Galvanostatic charge discharge cyclic stability. The charge discharge curves of FIG. 5B show that the module has good cyclic stability up to 2000 cycles. The supercapacitors module 100 has an area of 12.5 cm X 12.5 cm and have a pack of 12. A current of 50mA was used in the experiments.
[0037] The enhanced performance of the fabricated supercapacitor is more than the existing battery systems leading to increased lifetime. The innovation leads to simple process and cost-effective method of fabrication to make a commercially viable supercapacitor pack for 2-wheeler EVs.
[0038] The fabrication process used herein for the construction of supercapacitors is a simplified process and cost effective as it does not have the need for sophisticated equipment and can be fabricated at room conditions. These supercapacitors developed herein may be used for application in a two-wheeler electric vehicle in place of or in auxiliary with the existing battery system to enhance the performance and life. The performance of the electric vehicles will be enhanced with low running cost and increased life of the battery system.
The foregoing description gives examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, orders of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts necessarily need to be performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples. Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible. The scope of embodiments is at least as broad as given by the following claims. ,CLAIMS:1. A supercapacitor module (100) for two-wheeler electric vehicles (10), the supercapacitor module (100) comprising:
a plurality of supercapacitor units (110), wherein each supercapacitor unit (110) comprising:
two identical electrodes (112) comprising graphene-polyaniline nanocomposites;
an electrolyte comprising an aqueous inorganic acid; and
a polyethylene membrane separator (114).
2. The supercapacitor module (100) as claimed in claim 1, wherein the two electrodes (112) individually have a thickness in a range from 0.1 mm to 2mm.
3. The supercapacitor module (100) as claimed in claim 1, wherein the aqueous acid in the electrolyte comprises 0.1 molar to 1 molar PVA gelled H2SO4.
4. The supercapacitor module (100) as claimed in claim 1, wherein the separator (1140) has a thickness in a range from 0.1 mm to 1mm.
5. The supercapacitor module (100) as claimed in claim 1, wherein the supercapacitor module (100) comprises 12 supercapacitor units (110) with dimensions of 12.5 cm X 12.5 cm X 2 cm.
6. The supercapacitor module (100) as claimed in claim 1, wherein the supercapacitor module (100) has a voltage of 12 volts, capacitance of 200F, energy of 4.3Wh, power of 3kw, and weight of 1.15 kilograms.
7. A process for forming a supercapacitor module (100) for two-wheeler electric vehicles (10), the process comprising:
assembling 12 supercapacitor units (110) in series, wherein forming each of the supercapacitor unit (110) comprises:
forming and assembling two identical electrodes (112) comprising graphene-polyaniline nanocomposites;
forming an electrolyte comprising an aqueous inorganic acid and disposing the electrolyte in between the two electrodes;
and forming a polyethylene membrane separator (114) and disposing the separator (114) in between the two electrodes (112).
8. The process as claimed in claim 7, wherein forming the electrolyte comprises dissolving H2SO4 in poly vinyl alcohol (PVA) in a concentration in a range from 0.1 molar to 1 molar at a temperature in a range from 60 degrees Celsius to 70 degrees Celsius along with stirring.
9. The process as claimed in claim 7, wherein forming a polyethylene membrane separator (114) comprises coating a polyethylene membrane with PVA gelled electrolyte and drying in vacuum.