Inductance type fiber energy storage coil suitable for wireless charging

Abstract

An inductance type fiber energy storage coil suitable for wireless charging relates to the field of wireless charging and comprises an energy storage device and at least one diode, the energy storage device comprises a tube body with tube orifices at two ends, and a current collector combination is arranged in the tube body along the axial direction of the tube body. The current collector combination is composed of a positive electrode metal current collector and a negative electrode metal current collector which are spirally wound with each other, the tube body is further filled with electrolyte, the tube openings at the two ends are sealed by sealing parts, and at least part of the two ends of the current collector combination are located outside the tube body; the anode of the diode is connected with the other end of the cathode metal current collector, the cathode of the diode is connected with one end of the anode metal current collector, and the energy storage device is wound into a circle through the diode to form an energy storage coil. An existing receiving coil and an energy storage device are integrated, the size of the charging device is reduced, meanwhile, the charging efficiency can be improved, and rapid charging is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless charging, and in particular to an inductive fiber type energy storage coil suitable for wireless charging. Background Art

[0002] Most of the current products in the consumer electronics and electric vehicle fields use planar or cylindrical lithium-ion batteries as their energy supply units. The charging and discharging of these batteries are still mainly contact DC charging. The charging power of this charging mode is limited by the applied current. For example, the charging speed of smartphones is limited by the power of the charger, and the charging current of electric vehicles is already very large, but it still takes hours to charge. In general, during wired charging, the current of all energy storage units will be aggregated at the charger end, and the current will be quite large, exceeding the rated current of the charger and unable to achieve high-power charging. The charging efficiency of wired charging is low. More importantly, the traditional charging solution relies on a rectifier bridge composed of four Schottky diodes, which increases the complexity of the system and increases energy loss.

[0003] In addition to wired charging, there is also electromagnetic induction wireless charging technology, which is a wireless charging technology that uses the principle of electromagnetic induction. However, the wireless charging system includes a transmitter device (power module, power conversion circuit, control circuit and transmitting coil) and a receiver device (receiving coil, rectifier circuit, charging management circuit and energy storage device), and still cannot get rid of the complex charging circuit structure. Taking the charging module structure of a mobile phone as an example, the transmitter is usually integrated in the wireless charging seat, and the receiver is usually integrated in the device that needs to be charged. These structures not only make the charging device larger, but also make the circuit more complicated. Summary of the invention

[0004] In view of the shortcomings of the background technology, an object of the present invention is to provide an inductive fiber type energy storage coil suitable for wireless charging.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An inductive fiber-type energy storage coil suitable for wireless charging comprises an energy storage device and at least one diode, wherein the energy storage device comprises a tube body with tube openings at both ends, a current collector combination is arranged in the tube body along its own axial direction, the current collector combination is composed of a positive metal current collector and a negative metal current collector which are spirally wound with each other, the surfaces of the positive metal current collector and the negative metal current collector are coated with active materials and at least one of the metal current collector surfaces is wound with a diaphragm, the tube body is also filled with an electrolyte, the tube openings at both ends are sealed with sealing parts, and at least part of the two ends of the current collector combination are located outside the tube body; the anode of the diode is connected to the other end of the negative metal current collector, and the cathode of the diode is connected to one end of the positive metal current collector, and the energy storage device is wound into a circle through the diode to form an energy storage coil.

[0007] Furthermore, the number of the diodes is two, the anode of another diode is connected to one end of the negative electrode metal current collector, and the cathode of the diode is connected to the other end of the positive electrode metal current collector.

[0008] Furthermore, the separator is wound around the surfaces of the positive electrode metal collector and the negative electrode metal collector.

[0009] Furthermore, the positive electrode metal current collector is made of aluminum wire, and the negative electrode current collector is made of copper wire.

[0010] Furthermore, the active material coated on the surface of the positive electrode metal current collector is one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate or nickel cobalt lithium manganese oxide.

[0011] Furthermore, the active material coated on the surface of the negative electrode metal current collector is one of graphite, silicon or lithium titanate.

[0012] Furthermore, the diaphragm is made of polyethylene or polypropylene.

[0013] Furthermore, the electrolyte is a gel electrolyte or a lithium salt solution.

[0014] Furthermore, the sealing portion is made of epoxy resin or EVA hot melt adhesive.

[0015] Furthermore, the tube body is a heat shrink tube, a polyethylene tube or a polypropylene tube.

[0016] The beneficial effects of the present invention are:

[0017] 1. The present invention proposes a wireless charging system based on a fiber-type energy storage coil, which breaks through the physical limitations of traditional contact charging through functional fusion design. The system is based on the principle of electromagnetic induction, and directly places the fiber-type electrode with metal wire as the current collector as the receiving coil in the wireless charging system, realizing the functional fusion of the energy storage unit and the energy transmission coil.

[0018] 2. The present invention integrates the original receiving coil and energy storage device into one by using a half-wave rectification strategy of reverse series connection of a single fast ordinary switching diode, so that the system can maintain the simplicity of the circuit while only relying on the structure of the energy storage coil itself to rectify the alternating current into a unidirectional current, which greatly simplifies the size of the wireless charging device. The system uses the principle of electromagnetic induction to dynamically adjust the induced electromotive force of the secondary coil by adjusting the input voltage of the main coil, significantly improving the charging efficiency, and accurately maintaining the cut-off voltage of the fiber-type energy storage coil near the required voltage, effectively suppressing the side reactions caused by overpotential. At the same time, since this charging mode has the ability to independently charge the fiber-type energy storage coils of each winding, the charging efficiency can be improved by configuring a number of energy storage coils on the magnetic path to achieve fast charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A schematic diagram of an inductive fiber-type energy storage coil suitable for wireless charging according to the present invention;

[0021] Figure 2 Schematic diagram of the positive metal current collector and the negative metal current collector of the present invention;

[0022] Figure 3 is a schematic diagram of an energy storage device of the present invention;

[0023] Figure 4 is an equivalent circuit diagram of the wireless charging system of the present invention;

[0024] Figure 5 This is the connection diagram of the transformer model;

[0025] Figure 6 This is a curve diagram of the change of positive and negative voltages during wireless charging;

[0026] Figure 7 This is a charging principle diagram of the energy storage coil of the present invention;

[0027] Figure 8 This is the waveform diagram of the energy storage coil of the present invention when it starts to charge

[0028] Fig. 9 This is a waveform diagram of the energy storage coil during charging of the present invention;

[0029] Fig.10 This is a waveform diagram of the energy storage coil of the present invention when charging is nearly completed;

[0030] Fig.11 The wireless charging voltage variation curve when 1-10 units of fiber-type energy storage coils are connected in parallel;

[0031] Fig.12 The wireless charging voltage variation curve when 1-10 units of fiber-type energy storage coils are connected in series;

[0032] In the figure, 10, tube body; 20, positive metal current collector; 30, negative metal current collector; 40, active material; 50, diaphragm; 60, electrolyte; 70, sealing part; 80, diode; 90, energy storage coil. DETAILED DESCRIPTION

[0033] Combine the following Figure 1-12 The present invention is described in detail.

[0034] An inductive fiber-type energy storage coil 90 suitable for wireless charging includes an energy storage device and at least one diode 80. The energy storage device includes a tube body 10 with tube openings at both ends. A current collector combination is arranged in the tube body 10 along its own axial direction. The current collector combination is composed of a positive metal current collector 20 and a negative metal current collector 30 that are spirally wound with each other. The surfaces of the positive metal current collector 20 and the negative metal current collector 30 are coated with active materials 40 and at least one metal current collector surface is wound with a diaphragm 50. The tube body 10 is also filled with an electrolyte 60. The tube openings at both ends are sealed by a sealing portion 70. At least part of the two ends of the current collector combination are located outside the tube body 10. The anode of the diode 80 is connected to the other end of the negative metal current collector 30, and the cathode of the diode 80 is connected to one end of the positive metal current collector 20. The energy storage device is wound into a circle through the diode 80 to form the energy storage coil 90.

[0035] In this embodiment, the number of the diodes 80 is two, the anode of another diode 80 is connected to one end of the negative metal current collector 30 , and the cathode of the diode 80 is connected to the other end of the positive metal current collector 20 .

[0036] In this embodiment, a separator 50 is wound around the surfaces of the positive electrode metal collector 20 and the negative electrode metal collector 30 .

[0037] In this embodiment, the positive electrode metal current collector 20 is made of aluminum wire, and the negative electrode current collector is made of copper wire.

[0038] In this embodiment, the active material coated on the surface of the positive electrode metal current collector 20 is one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate or lithium nickel cobalt manganese oxide.

[0039] In this embodiment, the active material coated on the surface of the negative electrode metal current collector 30 is one of graphite, silicon or lithium titanate.

[0040] In this embodiment, the diaphragm 50 is made of polyethylene or polypropylene.

[0041] In this embodiment, the electrolyte 60 is a gel electrolyte or a lithium salt solution.

[0042] In this embodiment, the sealing portion 70 is made of epoxy resin or EVA hot melt adhesive.

[0043] In this embodiment, the tube body 10 is a heat shrink tube, a polyethylene tube or a polypropylene tube.

[0044] The present invention winds the fiber-type energy storage device into an inductor coil, and connects the diode 80 at the appropriate positions at the two ends of different electrodes, thereby realizing the integration of the wireless charging coil and the energy storage device. The magnetic field passing through the energy storage coil 90 will cause the voltage in the energy storage coil 90 to fluctuate when it produces periodic changes, thereby causing a potential difference between the two different ends of the two electrodes of the energy storage coil 90. When the diode 80 connects the two ends, a path will be formed. At the same time, due to the unidirectional conduction effect of the diode 80, current will only be generated when the direction of the voltage difference is along the conduction direction of the diode 80, thereby realizing the function of rectification, and the current only forms a closed loop between the two current collectors, the diode 80 and the electrolyte.

[0045] The structure of the energy storage coil 90 is based on the internal structure of a lithium-ion battery, and can also be based on the arrangement of electrochemical energy storage structures such as sodium-ion batteries and supercapacitors; in addition to being a metal wire, the metal current collector can also be a metal strip or other shape that approximates a metal wire.

[0046] The inductive fiber type energy storage coil 90 suitable for wireless charging proposed in the present invention has a manufacturing method as follows:

[0047] First make the energy storage device:

[0048] (1) First, prepare the positive and negative electrode slurries. The solid materials of the positive electrode slurry are lithium cobalt oxide: conductive carbon black: polyvinylidene fluoride = 92:3:5, solid material: N-methyl pyrrolidone in a ratio of 1:1 and stirred for 2 hours until uniform. The solid materials of the negative electrode slurry are graphite: conductive carbon black: sodium carboxymethyl cellulose: styrene butadiene rubber = 160:6:3:8, solid material: deionized water = 5:6 and stirred for 2 hours until uniform.

[0049] (2) The positive and negative electrode slurries are coated on the positive electrode current collector aluminum wire and the negative electrode current collector copper wire to make electrodes, and then placed in a vacuum drying oven for 24 hours to remove the solvent to obtain the positive and negative electrodes of the energy storage unit.

[0050] (3) Take the positive and negative electrodes, and smoothly wrap the separator 50 cut into long strips on one or both electrodes so that it completely covers the active material 40 on the surface of the current collector to prevent the two electrodes from directly contacting each other and causing a short circuit, thereby obtaining the following: Figure 2 The positive and negative electrodes are shown. The two electrodes are then twisted together to form a double helix structure, thereby reducing the distance between the electrodes and lowering the internal resistance.

[0051] (4) Next, a pre-gel electrolyte is prepared by adding lithium hexafluorophosphate as the solute to a solvent prepared by mixing ethylene carbonate (EC) and diethyl carbonate in a ratio of 1:1 to prepare a 1 mol / L liquid electrolyte, and then adding a small amount of polyethylene glycol dimethacrylate monomer thereto.

[0052] (5) Place the electrode in a heat shrink tube, fill it with electrolyte, seal the port with epoxy resin, and reserve 3-5 cm of current collector at both ends to connect the diode 80. Finally, place the packaged device on a hot table and heat it at 60°C until the electrolyte becomes gel-like. Finally, the following is obtained: Figure 3 The energy storage device shown.

[0053] Connection of energy storage device and diode 80:

[0054] One end of the positive electrode of the spiral structure of the fiber-type energy storage coil 90 is connected to the other end of the negative electrode through a diode 80, wherein the anode of the diode 80 is connected to the negative electrode of the fiber-type energy storage electrode, and the cathode of the diode 80 is connected to the positive electrode of the fiber-type energy storage electrode, so as to obtain Figure 1 The energy storage coil 90 is shown. The specific connection method is welding, and the steps of welding the diode 80 and the current collector refer to the common knowledge in the art. In addition, if the other two unconnected ends are connected with a diode 80 in the above manner, full-wave rectification can be achieved, further improving the charging power of wireless charging.

[0055] The inductive fiber type energy storage coil 90 suitable for wireless charging proposed in the present invention has the following working principle:

[0056] Performance characteristics of inductive fiber energy storage coil 90:

[0057] like Figure 5 As shown, taking the transformer model as the carrier of magnetic flux transmission as an example, the main coil is wound with 200 turns of enameled copper wire (the main coil is in the lower right corner of the figure), and the secondary coil is composed of an inductive fiber-type energy storage coil 90 (the main coil is in the lower left corner of the figure). The main coil is connected to an adjustable voltage 50Hz AC power supply. Apart from this, no other additional circuits are required. An oscilloscope can be used to monitor its charging voltage curve. When the main coil is connected to AC power, the partial change curve of the voltage of the energy storage coil 90 itself during the charging process is shown in the figure Figure 6 As shown, the voltage between the positive and negative electrodes gradually increases, realizing wireless charging of the inductive fiber energy storage coil 90 using the principle of electromagnetic induction.

[0058] At this time, the fiber-type energy storage coil 90 itself can be used as both a receiving coil and an energy storage device to store energy, and due to the function of the diode 80, an induced current will be generated in the energy storage device only when the current direction in the energy storage coil 90 is the conduction direction of the diode 80, so that it can rectify the received alternating current into a unidirectional pulse current. In addition, during the charging process, the voltage of the device itself gradually approaches the cut-off voltage. At this time, due to the voltage self-feedback mechanism of this structural system, the peak value of the pulse voltage gradually decreases, thereby preventing the energy storage device from being in a high-current charging environment all the time, and effectively protecting the energy storage device.

[0059] The specific charging principle of the energy storage coil 90 is:

[0060] The inductive fiber type energy storage coil 90 is simplified as follows Figure 7 As shown, the inner side represents the positive electrode, the outer side represents the negative electrode, and the electrolyte is filled between the positive and negative electrodes. When there is an alternating magnetic field in the coil, an induced electromotive force will be generated on the metal current collector of the fiber-type energy storage coil 90. At a certain moment, the positive and negative induced electromotive force of the fiber-type energy storage coil 90 are as follows: Figure 7 As shown, the diode 80 is turned on and current flows through it; when the induced voltage of the fiber-type energy storage coil 90 is opposite to this situation, the diode 80 is turned off, thereby realizing the charging process.

[0061] During the charging process, the voltage waveforms of the positive and negative electrodes of the inductive fiber type energy storage coil 90 are measured in detail. Figure 8 This is a waveform diagram at the beginning of charging. It can be seen that the voltage of the energy storage coil 90 is in the form of a unidirectional sinusoidal pulse, which is the result of half-wave rectification. Fig. 9It is a waveform diagram during the charging process. It can be seen that after each charging cycle, the low point of the pulse wave gradually moves up. This is because the voltage of the energy storage coil 90 acts as a DC bias. Only when the induced electromotive force voltage difference across the diode 80 is greater than the voltage of the energy storage coil 90, the diode 80 can be turned on. Fig.10 This is a waveform diagram when charging is nearly completed. Since the energy storage coil 90 is basically fully charged, the DC bias effect is relatively strong and the sinusoidal pulse is basically shielded by the DC bias.

[0062] Under the action of unidirectional voltage, the anions and cations in the electrolyte move to the active layers of the positive and negative electrodes under the electric field, and the corresponding electrochemical reactions occur, thus realizing the charging process of the energy storage unit. The specific current loop is that the current flows from the negative electrode to the positive electrode through the diode 80, and at the same time, the anions in the electrolyte move to the positive electrode and the cations move to the negative electrode. Finally, the overall loop of the charging current is confined inside the fiber-type energy storage unit.

[0063] In summary, when the magnetic flux passing through the coil changes, voltage fluctuations will occur on the current collector of the fiber-type energy storage device. Under the action of the diode 80, it is equivalent to adding a dam in the fluctuating voltage, realizing a directional change of the electric potential in the voltage fluctuation, and finally realizing the charging of the fiber-type energy storage device.

[0064] In addition, by adjusting the input voltage of the AC power supply, the maximum cutoff voltage of the fiber-type energy storage coil 90 can be directly adjusted to prevent overcharging, without the need for additional voltage settings. In addition, the device can be used as an external energy storage device alone, or directly used by replacing the battery in electronic devices, such as mobile phones, watches, etc.

[0065] The present invention integrates the receiving coil and the energy storage device into one, and does not require a rectifier circuit. The charging cut-off voltage of the energy storage device can be correspondingly regulated by adjusting the value of the input voltage, thereby simplifying the circuit of the device and reducing its size.

[0066] The daily charging methods (wired and existing wireless) require that the corresponding charging current or voltage and the volume of the charging module be increased when the capacity of the energy storage device is expanded. However, the present invention can easily achieve the capacity increase by simply configuring multiple groups of fiber-type energy storage devices together on the magnetic flux line. According to the principle of electromagnetic induction, the charging between each group is completely independent, so there is no need to increase the input current or voltage and additional charging modules, so the parameters of the single group charging can be maintained, and its volume is not greatly increased. Since the charging is carried out simultaneously, the time required for charging is also the same as that of the single group, and the pulse current has a certain relaxation effect, thereby achieving the effect of increasing the charging power.

[0067] Specifically, the voltage and capacity expansion of the inductive fiber type energy storage coil 90: By connecting the two terminals of the energy storage coil 90 in series or in parallel, the voltage (series) or capacity (parallel) expansion can be achieved. The charging waveform after expansion is as follows Fig.11 (in parallel) and Fig.12 (in series), it can be clearly seen that although multiple units have been expanded, the charging time is basically the same as that of a single unit, and the charging loop is limited to a single energy storage coil 90. This shows that this charging mode can enable multiple charging units to be charged simultaneously and independently. If factors such as mutual inductance and flux loss are not considered, an infinite number of energy storage coils 90 can be integrated on the flux line and charged at the same time, while only affecting the current of the main coil (in mature transformer technology, the current of the main coil can be very large, which is different from the current in DC charging), and will not cause heat generation due to excessive current, thereby causing damage to the energy storage device. Therefore, compared with the defect of large terminal current in DC charging, the present invention has greater potential for high-power charging.

[0068] Fiber-type energy storage devices have good mechanical properties. They can not only replace the charging and energy storage modules in electronic devices such as mobile phones, but also when there are flexible components in electronic devices, the coil can serve as an energy storage module and replace the position of the component to play the original role of the component (such as watch straps, etc.).

[0069] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. An inductive fiber type energy storage coil suitable for wireless charging, characterized in that: The invention comprises an energy storage device and at least one diode, wherein the energy storage device comprises a tube body with tube openings at both ends, a current collector combination is arranged in the tube body along its own axial direction, the current collector combination is composed of a positive metal current collector and a negative metal current collector which are spirally wound with each other, the surfaces of the positive metal current collector and the negative metal current collector are coated with active materials, and at least one of the metal current collectors is wound with a diaphragm, the tube body is also filled with an electrolyte, the tube openings at both ends are sealed by sealing parts, and at least part of the two ends of the current collector combination are located outside the tube body; the anode of the diode is connected to the other end of the negative metal current collector, and the cathode of the diode is connected to one end of the positive metal current collector, and the energy storage device is wound into a circle through the diode to form an energy storage coil.

2. An inductive fiber type energy storage coil suitable for wireless charging as claimed in claim 1, characterized in that: The number of the diodes is two, the anode of another diode is connected to one end of the negative metal current collector, and the cathode of the diode is connected to the other end of the positive metal current collector.

3. The inductive fiber type energy storage coil suitable for wireless charging according to claim 1, characterized in that: The separator is wound around the surfaces of the positive electrode metal collector and the negative electrode metal collector.

4. The inductive fiber type energy storage coil suitable for wireless charging according to claim 1, characterized in that: The positive electrode metal current collector is made of aluminum wire, and the negative electrode current collector is made of copper wire.

5. The inductive fiber type energy storage coil suitable for wireless charging according to claim 1, characterized in that: The active material coated on the surface of the positive electrode metal current collector is one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate or nickel cobalt lithium manganese oxide.

6. The inductive fiber type energy storage coil suitable for wireless charging according to claim 1, characterized in that: The active material coated on the surface of the negative electrode metal current collector is one of graphite, silicon or lithium titanate.

7. The inductive fiber type energy storage coil suitable for wireless charging according to claim 1, characterized in that: The diaphragm is made of polyethylene or polypropylene.

8. The inductive fiber type energy storage coil suitable for wireless charging according to claim 1, characterized in that: The electrolyte is a gel electrolyte or a lithium salt solution.

9. The inductive fiber type energy storage coil suitable for wireless charging according to claim 1, characterized in that: The sealing part is made of epoxy resin or EVA hot melt adhesive.

10. The inductive fiber type energy storage coil suitable for wireless charging according to claim 1, characterized in that: The tube body is a heat shrink tube, a polyethylene tube or a polypropylene tube.

Images