Introduction: Quantum Battery
This instructable describes a way to be created a very high efficiency battery.
It is more theoretical because it requires high technologies and big investments, but I would like to share the idea with the hope that this work could be read by the proper person, having the ability to prove it concept and to implement it in practice.
Now I have started a project at Kickstarter, in which I want to proof the idea. Please, support it.
I would like to make an apology to the all authors, which pictures and graphs I have used, without citations of the source. The reason is that these are found in Internet a time ago and the source information is lost.
Step 1: Principle of Work
The principle of work of the Quantum battery is based on the Quantum Mechanics phenomenon of the electron tunneling. More concrete information about this process can be found here. I will summarize this phenomenon in few words: The movement and the energy of the electron is described by its wave function. It is solution of the Schrödinger equation and it predicts that in some cases the electron can tunnel through potential barriers, or in other words - it can jump from one place to another without energy loss. The modern physics claim that the quantum tunneling is the main mechanism, which allows the stars to radiate light - the photons generated inside the core of the star tunnel to its periphery and thus can be freed in the space as free energy. Some more close to us example is the EEPROM (memory used almost in each electronics device today). An EEPROM chip contain a millions / billions of special electronic devices called FGMOS (Floating gate MOS transistors), which work is based on the electron tunneling.
On the picture above is given a cross section of a FGMOS transistor. This picture is taken by electron microscope with very high magnification (x10 000). On the picture can be seen the two poly (poly-silicon) gates. The poly1 gate is the floating one. It is totally isolated from all other active areas of the device. It is surrounded from all its sides by high quality insulator. Under the right bottom part of the floating gate can be seen that this insulator layer is very thin. This region is the place where the tunneling happens. Over the floating gate of the FGMOS is placed one or multiple poly-silicon gates (poly2) which do not have any electrical contact with the floating gate. They are called control gates (one or more). The process of the electron tunneling to the floating gate is invoked in the following way (see the second picture): between the chip substrate (normally p-type monocristalline silicon) and the control gate/s relatively high voltage source is connected (in the FLASH/EEPROM chips this voltage is generated by special charge pumps). The electrons are attracted by the appeared high electric field and jump through the tunnel oxide in the floating gate, charging it in this way negatively. On the third picture can be seen how the potential of the floating gate changes with the time because of the increasing of the number of tunneled electrons inside it. Because the floating gate is perfectly isolated once charged it can keep its charge for very long periods (the normal time for FLASH and EEPROM memories is over 10 years!).
I would not get deeper inside this quantum mechanics process. I would like only to mention, that the tunneling electron flow from the substrate to the floating gate (called further tunneling current) is based on few physical parameters of the materials used, depend on the strength of the applied electric filed! and can be predicted by the Fowler – Nordheim formula.
Step 2: The Battery Structure....
Now we know what FGMOS is and how it works....
How can this give us an energy?!?
Now, let us connect N - millions /billions of FGMOS’s in parallel ( on a 32GB FLASH chip the number of FGMOS transistors can be over 70 000 000 - normally for each memory cell 2 FGMOS are used for security reasons):
1.All sources, drains and the substrate are connected together in one network. Let's call this network "Anode" or "Injector" (because it injects the electrons in the FG) and connect it to the negative pole of external battery with voltage Vprog (can be ~12-20 V)(Remark:sources and drains are current passing terminals of MOS devices) .
2.All floating gates are connected together in one network. Let's call it "Cathode"
3.All control gates are connected together - making the "Control plate"
When we apply the high voltage (Vprog) at the "Control plate" the tunneling current will start to flow.
The tunneling current IFN will be~ N*A*JFN, where A is the area of the single FGMOS and JFN is the tunelling current density per unity area calculated using the Fowler – Nordheim formula.
At very high numbers of N or big floating gate (FG) areas the tunneling current can reach very high values!
The picture used taken from Wikipedia, author Felix Kling
Step 3: How It Works...
The questions still remains....
Let us simplify the whole system by use of the capacitors. We can distinguish three main capacitors:
1)CCP-C – the capacitor between the Control plate and the Cathode
2)CINJ-C – the capacitor between the Anode and the Cathode
3)CINJ-CP – the capacitor between the Anode (Injector) and the Control plate
The schematic presentation of the simplification is presented on the picture above.
Step 4: How It Works (part 2)....
When Vprog is applied the IFN current starts to flow. It charges the Cathode plate negatively to the potential Va-c, which increases with the time (its absolute value). Because the voltage on the Ccp-c also changes with the time – a current Icp-c flows from the Vprog source.
Icp-c = Ccp-c * d(|Vprog| + |Va-c|)/dt
Step 5: How It Works (part 3)....
When the voltage Va-c reaches some desired value, let us connect between the Cathode and the Anode a tunable resistive load and adjust its resistance RL in the way that the load current IL=Va-c/RL becomes equivalent to the IFN !
Then the charge on the capacitor CINJ-C remains constant! Va-c remains constant! That means that the charge stored in the capacitor CCP-C : Q(CCP-C) also remains constant because the voltage VC-CP remains also constant !
The current from the voltage source Vprog stops flowing!!!
NO ENERGY WILL BE CONSUMED FROM THE SUPPLY – BUT ENERGY IN THE LOAD WILL BE DISSIPATED !!!
Step 6: Possible Realization and Technology Chalenges
As discussed in the previous steps: Based on the quantum mechanics process of the electron tunneling, a very high efficiency battery can be produced. It will contain 5 layers - 3 conductive (metal or semiconductor) and two insulator layers ordered in a sandwich like structure . The bottom layer called Anode (Injector) is conductive. it serves as positive pole of the quantum battery. Over this layer the second conductive layer called Cathode is placed. Both layers are isolated by the use of thin dielectric layer (the tunneling dielectric). Its is possible that this layer is vacuum - technology solution must be found. The thickness of the mentioned dielectric layer (distance between the anode i cathode) is very small (in order of few nanometers). Over the three mentioned layers another dielectric layer is placed. Its thickness can be in orders higher comparing with the first one. At the top of this whole structure is placed the fifth layer (3-rd conductive) which is used to control the process of the electron tunneling. All conductive layers can be patterned in the way that the maximum tunneling current density is achieved.
Here I want to list the possible technology challenges
:1) Main problem of the FGMOS transistors is that with the time the tunneling electrons destroy the structure of the tunneling oxide. Materials which can sustain the destructive tunneling electron flow must be found. May be the use of new nano -materials can solve the problem. If a vacuum is used - the problem will be solved. The main problem then will be how to keep the Anode and Cathode plates at the right distance.
2) The invoking of high tunneling currents will require high electric fields. Using special structures of the Anode(Injector) plate can improve the electron tunneling probability (now the tunneling current density is estimated to be~ 10A/m2) . Here also helpful can be the nanotechnology. The pictures above show surfaces created by the use of the nanotechnology and may be they can be suitable for use as injector plates. Using such kind of surfaces will lead to decrease of the Vprog voltage.
3) The optimal structure of the three electrode networks must be found in the way, that the injector electrode emits as much, as possible electrons, the Cathode plane “catches” all of them, the Control plate creates the necessary electric field to cause the tunneling, but stays only capacitive connected to the other two planes.
Step 7: Conclusion
Using the proposed approach a very high efficiency energy source can be created. Based on the nano- and micro-technologies it will be possible to implement the energy source with small dimensions but big current driving capability and efficiency. Properly designed the battery will serve lifelong without any charging (at the time now current densities 10 A/meter square are calculated, but it is not the limit).
Using multilayer structure a power source delivering 100-300A can be realized inside a volume of few liters.
All said here sounds like perpetual machine, but the trick is that before and after the tunneling the electrons don’t change their energy and their transfer doesn't require power from the external high voltage battery, which current can be zero. Using serial connected Quantum batteries the needed voltage can be reached. When a single battery is designed having multiple parallel sections and switching them ON/OF - connecting or disconnecting them the driven current can be adjusted regarding the current need of power – in this way keeping the output voltage constant and the current from the high voltage external battery near zero.
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