FIELD OF THE INVENTION:

The present invention generally relates to energy storage devices. More particularly, the present invention relates to a super capacitor system and method for improving energy extraction from the same.

BACKGROUND OF THE INVENTION:

A quantitative property transferred to an object in order to perform a work / task is called an energy. The requirement of energy is continuously increasing in day to day life, therefore the storage of energy plays a vital role. The different types of energy storage devices involve converting energy from difficult form to more conventionally storable form in order to store energy in the storage devices. Many developments have made in energy storage systems to store energy in an efficient way.

With the advent of increasing automotive vehicles in day to day life, results in lack of fossil fuels. To avoid such complications, automobile industries have taken few steps ahead for automotive with various kinds of energy resources through multiple technologies. Now, the fuels for vehicles have shift from hydrocarbons to multiple alternative resources and finally reaches to the stage of electric vehicle.

A pollution free electric vehicle uses electric motor for their propulsion that are powered by any energy sources like batteries in recent scenario. The charging process for batteries are based on a chemical reaction that takes place between an electrolyte and two electrodes called an anode and cathode. The capacity to store electric charge in the battery is a function of the surface area of these electrodes and the particular electrolyte used.

Common types of batteries include sealed lead acid (SLA) batteries, nickel-cadmium (Ni—Cd) batteries, and lithium-ion (Li-Ion) batteries. SLA batteries can hold a charge for up to three years and are generally used to provide backup power during emergencies. Ni—Cd batteries provide a fast charge as well as discharge and are most often used to power some appliances or audio and video equipment etc. Li-Ion batteries have the highest energy storage capacity (i.e. twice the capacity of Ni—Cd batteries) and are used to power portable computers, cellular phones, and digital cameras.

Currently, the dominating energy storage device remains the battery, particularly the lithium-ion battery. Lithium-ion batteries power nearly every portable electronic device, as well as almost every electric car. The charge and discharge process in batteries is a slow process and can degrade the chemical compounds inside the battery over time. When batteries have a low power density, it will lose their ability to retain energy throughout their lifetime due to material damage. If the batteries charge slowly then it would discharge slowly. Current demand of electric vehicles is asking for faster charging equivalent to fuel filling time in fossil fuelled vehicles.

Another type of battery known as super capacitors also called as electric double layer capacitor or ultra-capacitor that are used in the electric vehicles. Super capacitors are known to have high power density to deliver huge amount of power very quickly in seconds and can be charged in seconds.

However, when the supercapacitors discharges, it drops the terminal voltage too fast and it gives varying terminal voltage. Hence, efficient extraction of energy from very low voltage becomes impossible. There were several attempts done to draw extra power during high load requirements by placing it in parallel. The attempt was not successful due to the fact that standard battery keeps a constant voltage for long period till completely discharged. Whereas the voltage across the capacitor drops rapidly to a voltage at which energy extraction becomes impossible even if large amount of energy still available with them.

To overcome the above-mentioned problem, the present invention proposes a system and method to make the energy extraction process more efficient and helps to bring supercapacitors as mainstream energy storage device.

SUMMARY OF THE INVENTION:

The objective of the present invention is to solve the aforementioned problems and complications by proposing an effective system and method for extracting energy from supercapacitors in a shorter duration of time.

The present invention proposes a system and method that permits the dynamic arrangement and re-arrangement of supercapacitors in order to achieve a near constant voltage and enables the load to utilize most of the energy from it. The arrangement has one active switch component to put more capacitors in series in order to increase terminal voltage during discharge cycle. Also, the arrangement has one voltage stabilizer to step up and down automatically based on the input voltage in order to maintain a constant output voltage drop across the load.

In the present invention, the system has a supercapacitor bank having a non-conductive container with lot of slots to hold individual supercapacitors and wirings. By connecting more capacitors in series using a passive smart switch dynamically to attain higher voltage output. When voltage drops from V(peak) to V(threshold) a set of n number of capacitors are removed from parallel mode and re-arranged to series mode to bring back the V(peak). Hence, the voltage range is always between V(peak) to V(threshold).

In accordance with the present invention, the supercapacitor bank contains a non-conductive container containing lots of individual supercapacitors and wirings. The voltage from the individual supercapacitors is transmitted to the active switch through connectors called as connecting wires where the connectors are used to support the switching of operating mode (i.e. Series mode & Parallel mode) of supercapacitors. The active switch in the circuitry controls the arrangement of capacitors either in series mode or parallel mode based on the voltage drop. Now, the output voltage from the active switch is transmitted to stabilizer via an intermediate output voltage meter. The intermediate output voltage meter measures the voltage before it reaches stabilizer unit. The DC voltage stabilizer to stabilize the DC voltage by stepping up and stepping down the received voltage to desired range and the stabilized voltage is outputted via output socket.

The objective and advantages of the present invention will become more evident from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS:

The objective of the present invention will now be described in more detail with reference to the accompanying drawings, in which:

FIG. 1 represents the block diagram of the present invention with high-level view of components with major functions;

FIG. 2 shows the graphical representation of energy extraction by putting capacitors a) in parallel b) in series;

FIG. 3 shows the graphical representation of discharging time of capacitor against voltage drop;

FIG. 4 shows the design of smart switch; and

FIG. 5 shows the design of individual series parallel controller.

REFERENCE NUMERALS:

1: Super capacitor bank
2: Individual super capacitors
3: Connecting wires
4: Active switch
5: Intermediate output voltage meter
6: DC voltage step up and stepdown stabilizer
7: Final output socket
8: Series-Parallel controller switch
9: Power MOSFET switch

DETAILED DESCRIPTION OF THE INVENTION:

The present invention discloses an improved energy extraction system and method from supercapacitors in a supercapacitor bank and charging the supercapacitors with minimal time consumption. The method involves charging and discharging of supercapacitors to a required high-power density in order to maintain the high terminal voltage as well as near constant voltage drop across the load.

The present invention describes the super capacitor bank (1) contains a non-conductive container with multiple slots to hold number of individual supercapacitors (2) separately and it permits the supercapacitors to be charged and discharged very quickly like in seconds in order to use as a power source e.g. power source for electric vehicles. By connecting more number of capacitors in series or parallel depends on the application of load requirement and duration of high current demand, higher voltage energy extraction is attained.

In the present invention, the supercapacitor bank (1) comprising: number of individual super capacitors (2), connecting wires (3), an active switch (4), an intermediate output voltage meter (5), a DC voltage step up and stepdown stabilizer (6), a final output socket (7), one or more series-parallel controller switch (8) and a power MOSFET switch (9).

According to the present invention, the supercapacitor bank (1) has a non-conductive container containing lots of individual super capacitors (2) and wirings (3). The voltage from the individual supercapacitors is transmitted to the active switch (4) through connectors (3) called connecting wires where the connectors are used to control the operating mode of supercapacitors. The active switch (4) in the circuitry controls the arrangement of capacitors either in series mode or parallel mode based on the voltage drop. Now, the output voltage from the active switch (4) is transmitted to stabilizer (6) in order to stabilize the voltage received from active switch (4) via an intermediate output voltage meter (5). The intermediate output voltage meter (5) measures the voltage before it reaches stabilizer unit. The DC voltage stabilizer (6) to stabilize the DC voltage by stepping up and stepping down the received voltage into desired range and the stabilized voltage is outputted via output socket (7).

Referring to FIG. 1, it represents the high-level view of components involved in the present invention and their functions. The improved energy extracting system of the present invention comprises: a supercapacitor bank (1) having a non-conductive container to hold number of individual supercapacitors (2) which are connected by wirings (3), where the connecting wires (3) are used to control the mode of operation, an active switch (4) to control the arrangement of capacitors either in series or parallel based on the voltage requirement from the load, an intermediate output voltage meter (5) to output the voltage before stabilization, a DC voltage step up and stepdown stabilizer (6) to automatically step up and down based on the input voltage to maintain a constant output voltage drop across the load, a final output socket (7) to deliver the output voltage from supercapacitor bank, series-parallel controller switch (8) and a power MOSFET switch (9).

By referring to FIG. 1, it shows the arrangements of super capacitor bank (1) contains a non-conductive container with individual super capacitors (2). They can be charged in seconds and has long life i.e. more than 1 million charging cycles. The super capacitors (2) provide spike load, battery protection and longer battery life and thus are idle candidate for any of the high-power burst applications such as audio amplifiers, UPS, LASER, forklifts. The super capacitors (2) can be charged from various energy sources not limiting to grid, solar energy and thermal energy. The dynamic arrangement and re-arrangement of supercapacitors (2) in the present invention is used to achieve a constant voltage and enables the load to utilize most of the energy from it.

The non-conductive container of the super capacitor bank (1) contains many even numbered capacitor cells (2) where the number of capacitors (2) depend on the application of load requirement and duration of high current demand. As shown in FIG. 1 the circuitry has one passive component called active switch (4) that handles arrangements to connect more capacitors (2) in series to increase terminal voltage during at discharge cycle. The output from number of the capacitors (2) are multiplexed at active switch to form a single output, where the active switch has one or more series / parallel controller (8) with a power MOSFET switch (9). The circuitry also has one active component called DC voltage stabilizer (6) to step up and step down the voltage automatically based on the input voltage to maintain a constant output voltage drop across the load through final output socket (7).

According to the present invention, each cell (2) has a terminal voltage of 2.7 volts at fully charged condition (B) as shown in FIG. 2(a). The energy extraction is possible when the voltage of single supercapacitor (2) drops linearly from fully charged condition (B) to certain voltage range (D) (example: 1.2 volts). Upon reaching the point (C) (in this case, 1.5 volts), the energy extraction is almost impossible.

To avoid this inconvenience, 18 capacitors are arranged in series in accordance with one aspect of the present invention, hence the circuit achieves maximum voltage of 48 volts at fully charged condition (B’) (in this case, may vary depending on application). Higher energy extraction occurs when the voltage drops from fully charged condition (B’) to certain range (D’) i.e. the range of 48 - 1.5 volts as shown in FIG. 2 (b). This also has the same voltage characteristics as the capacitor discharges, however the higher voltage energy extraction is much easier.

In an illustrative example, the energy calculation based on capacitors arrangement in the circuitry according to the present invention is calculated as follows:

1) Capacitors in parallel connection:
Let capacitance C = 100F
Total energy that can be extracted in the range of 2.7v to 1.5v
e = 1/2 * C (V22 – V12)
(Or) e= 0.5 * 100 (2.7*2.7 – 1*1) = 252 Joules
(Or) energy from 18 capacitors in parallel = 18*314.5=4536 Joule

2) Capacitors in series connection:
Let capacitance C = 100F
1/C = 1/C1 + 1/C2+… = 18/C = 18/100-> C=100/18
e = 1/2 * C (V22 – V12) = 0.5*(100/18) * (482-1.52) = 6393 Joules

Therefore, the energy Improvement = (6393-4536)/4536*100= ~40%

Though supercapacitors have the potential to extract good amount of extra energy when connected in series, it has a major problem of offering a very wide voltage output ranging from maximum voltage (B’) to minimum voltage (C) (in this case, 48 volts to 1.5volts). Therefore, the DC-DC voltage stabilizer (6) is used to draw very high current at low input and low current at high input voltage. This requires larger components like coils / transformers, capacitors and wiring, and clocking circuit which makes it inefficient to work in such wide range of input. If the input voltage range to the DC-DC stabilizer (6) is narrowed, the stabilizer (6) provides a lean design with higher efficiency. To attain higher voltage output (B’), more capacitors (2) are connected in series by using an active switch (passive smart switch) dynamically. When voltage drops from V(peak) (B’) to V(threshold) (E) (example: 36 volts). The n-number of capacitors (2) removed from parallel mode and re-arranged to series mode to bring back the V(peak) (B’). Hence the voltage always ranges between V(peak) (B’) to V(threshold) (E) as shown in FIG. 3.

FIG. 4 of the present invention represents the design of smart switch having number of series parallel controllers (8) connected with number of individual supercapacitors (2). FIG. 5 illustrates the design of individual series / parallel controller (8) with a power MOSFET switch (9). Based on the power requirement, the capacitors (2) are connected either in series mode or in parallel mode by smart switches. The output from multiple series / parallel controller (8) is given to a single series / parallel controller and produce stabilized final output voltage. By changing the switch terminals to ON or OFF, the series and parallel connection is enabled.

The present invention has functional advantages of supercapacitor over the general Lithium-ion battery is given below as a comparison table.

Function Supercapacitor Lithium-ion (general)
Charge time
Cycle life
Cell voltage
Specific energy (Wh/kg)
Specific power (W/kg)
1–10 seconds
1 million or 30,000h
2.3 to 2.75V
5 (typical)
Up to 10,000
20–60 minutes
500 and higher
3.6V nominal
120–240
1,000–3,000

Thus, the supercapacitor of the present invention is used as a power source for various load applications including, but not limited to portable electronic devices, home appliances and electric vehicles. The supercapacitor brings the capability of superfast charging and one million charging cycles. With the present proposed innovative approach, supercapacitors can overcome the challenge of inefficient energy extraction and be a main stream among energy storage device.

While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope of the invention as claimed.

Claims:

1. A system for extracting energy from super capacitor comprises:
a. a super capacitor bank (1) to hold plurality of individual supercapacitors (2) wherein said individual supercapacitors (2) is used to store high power density and deliver huge amount of power with shorter period of time;
b. one or more connectors (3) to support the switching of mode of operation;
c. an active switch (4) to control the arrangement of said individual supercapacitors (2), wherein said active switch (4) comprises:
i. one or more series-parallel controller switch (8) to make connection with said individual supercapacitors (2) based on load requirement; and
ii. A power MOSFET switch (9) to control a power output for loads.
d. an intermediate output voltage meter (5) to measure said output voltage received from said active switch (4);
e. a DC-DC voltage stabilizer (6) to stabilize said output voltage by step up or step down said voltage received from said intermediate output voltage meter (5); and
f. a final output socket (7) to deliver power to load.

2. The system as claimed in claim 1, wherein said supercapacitor bank (1) has n-number of individual supercapacitors (2) to store high power density and deliver huge amount of power with shorter period of time with respect to load requirement.

3. The system as claimed in claim 1, wherein said active switch (4) handles arrangement of supercapacitors (2) to increase the terminal voltage during discharge cycle.

4. The system as claimed in claim 1, wherein said step up and step down is performed automatically by DC-DC voltage stabilizer (6).

5. The system as claimed in claim 1 or 4, wherein said DC-DC voltage stabilizer (6) stabilizes said output voltage based on voltage to maintain a near constant output voltage across said load.

6. A method for extracting energy from supercapacitor comprising the steps of:
a. connecting more number of individual supercapacitors (2) into series by using an active switch (4) dynamically to attain higher voltage;
b. controlling the mode of operation using connectors (3) given between each of said supercapacitors (2) and said active switch (4);
c. transmitting said controlled output from active switch (4) to DC-DC voltage stabilizer (6);
d. stabilizing said received output voltage from active switch (4) by step up or step down said voltage; and
e. sending final output voltage to a final output socket (7) to deliver required power output.

7. The method as claimed in claim 6, wherein said output voltage from said active switch (4) is measured using intermediate output voltage meter (5) before entering to said DC-DC voltage stabilizer (6).

8. The method as claimed in claim 6, wherein a set of n number of individual super capacitors (2) removed from parallel and added to series to bring back to V(peak), when voltage drops from V(peak) to a V(threshold).

9. The method as claimed in claim 6, wherein said mode of operation is controlled by switching the connection between said supercapacitors either from series mode to parallel mode or parallel mode to series mode.