Lithium-sulfur battery system with constant voltage output and application thereof

Abstract

The invention discloses a lithium-sulfur battery system with constant voltage output, which comprises at least one lithium-sulfur battery pack, each lithium-sulfur battery pack is connected with a DC / DC converter for voltage stabilization and then is connected in series and / or in parallel, each lithium-sulfur battery pack comprises a box body and at least one lithium-sulfur battery soft package battery cell monomer arranged in the box body, each lithium-sulfur battery soft-package battery cell monomer is connected with the DC / DC converter for voltage stabilization, and the lithium-sulfur battery soft-package battery cell monomers are connected in series and / or in parallel to form the lithium-sulfur battery pack. The assembling method of the lithium-sulfur battery pack in the lithium-sulfur battery system is simple, the module weight is reduced, the lithium-sulfur battery pack or the lithium-sulfur battery system can be modularly designed according to actual application scenes, the output voltage of a power supply can be dynamically adjusted according to the requirements of third-party equipment, the popularization and application of lithium-sulfur battery products are effectively improved, and the application prospect is wide. Commercialized application of the lithium-sulfur battery is effectively promoted, and replacement of a traditional lithium ion battery can be realized to a certain extent.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium-sulfur batteries, and in particular relates to a lithium-sulfur battery system with constant voltage output and application thereof. Background Art

[0002] Lithium-ion batteries are a green and renewable energy source and one of the current research focuses in the battery field. However, the theoretical capacity of the positive electrode materials of traditional lithium-ion batteries is low and the cost is high, which makes it difficult to meet the demand for high-performance lithium batteries. Therefore, the lithium-sulfur battery system has attracted the attention of scientific researchers in recent years. Compared with traditional lithium-ion batteries, lithium-sulfur batteries have higher theoretical specific capacity and theoretical energy density, and with the advantages of abundant sulfur reserves and low prices, they are considered to be one of the batteries with the most development potential and can be widely used in portable electronic products, power vehicles, and drone applications.

[0003] Although lithium-sulfur batteries have many advantages, they still face many technical challenges in commercial applications, such as low life due to the polysulfide shuttle effect, low utilization of sulfur cathodes, and large volume expansion effects. In order to accelerate the industrial application of lithium-sulfur batteries, it is necessary to conduct appropriate application-level research outside the lithium-sulfur battery material layer to overcome these bottlenecks. From the application level, the voltage characteristics and discharge behavior of lithium-sulfur batteries are different from those of traditional lithium-ion batteries. The open circuit voltage of lithium-sulfur batteries can reach more than 3 V. In actual use as a power source, the voltage window of lithium-sulfur batteries is generally 1.7V~3.0 V, and its voltage-capacity curve has two platforms. During the discharge process, the first discharge platform appears at about 2.3V. The corresponding first-stage electrochemical reaction is that sulfur obtains electrons and is reduced to long-chain polysulfides. Although the conductivity of elemental sulfur and long-chain polysulfides is very low, since Li2S8, Li2S6 and Li2S4 can be dissolved in the electrolyte, they will not affect the subsequent electrochemical reactions of elemental sulfur. Therefore, the reaction rate in the first stage is very fast, and the capacity provided by this process can account for one-quarter of the theoretical capacity. The longer discharge platform at about 2.1 V corresponds to the second stage of the discharge process, in which long-chain polysulfides are converted into Li2S2 and Li2S that are insoluble in the electrolyte and deposited on the surface of the conductive material. The kinetic performance of this process is poor, mainly because the conductivity of Li2S2 and Li2S is extremely low and attached to the surface of the conductive material, which reduces the electron transport capacity and the reaction kinetics is relatively slow. At the end of the reaction, it will also cause a very large polarization, and the lithium-sulfur battery will show a very fast voltage drop. On the voltage-capacity curve, it is shown as a relatively gentle discharge curve at about 2.1 V, followed by a significant drop in voltage. The capacity provided by the second stage reaction accounts for three quarters of the theoretical capacity and is the main contributor to the capacity of lithium-sulfur batteries. It can be seen that compared with the relatively stable voltage output of lithium-ion batteries, the voltage fluctuation of lithium-sulfur batteries is large and changes rapidly, which puts high demands on the electrical equipment using lithium-sulfur batteries.

[0004] There are many components in electrical equipment, most of which require a stable power supply voltage. The stability of the power supply voltage is also a key factor for the smooth use of the power supply. For example, the flight control system of a drone relies on precision electronic components, including microcontrollers, sensors, and communication modules, which usually require a stable power supply. If the voltage is unstable, it may cause the system to restart, communication interruption, or even loss of control of the drone. In addition, other portable electronic devices such as tablets and wearable devices are also sensitive to voltage fluctuations. Instable voltage may cause abnormal operation of the device or even damage the hardware. At the same time, due to the limited voltage and capacity of lithium-sulfur single cells, series-parallel battery packs are required for use in many occasions. In the application of power battery packs and energy storage systems, it is common to connect hundreds of batteries in series. If any of the hundreds of batteries in series have problems, it will have serious consequences for the battery pack. Since it is difficult to achieve complete consistency between single-cell batteries in series, this will cause inconsistent voltages of single-cell batteries during charging and discharging, resulting in large changes in the output voltage of the entire battery pack, and even safety hazards. There are not many related studies on lithium-sulfur battery systems in the prior art, and most of the studies only involve the lithium-sulfur battery material side. For example, CN104054209A discloses an aqueous electrolyte lithium-sulfur battery, which has an anode structure comprising an electroactive material, a cathode comprising a solid electron transfer medium, an aqueous electrolyte in contact with the electron transfer medium, and an active sulfur species in contact with the aqueous electrolyte, wherein the anode electroactive material is separated from the aqueous electrolyte. The combined use of aqueous electrolytes and cheap sulfur as a cathode active material can be a key driver for the power and automotive industries, providing cost-effective and miniaturized solutions for load balancing, electric vehicles, and renewable energy storage. CN118100334A discloses a charging equalization control circuit for lithium-sulfur batteries. During initial charging, the charging control chip MCU first outputs a pulse signal, which is converted into a voltage signal by a driving chip and output to the charging equalization circuit. The charging circuit drives the MOSFET tube to turn on according to the voltage signal to start charging the battery. When the battery voltage exceeds a preset value, the charging control chip MCU outputs a pulse signal, which drives the MOSFET tube to turn on through the driving chip, and the equalization circuit starts to work. The charging management chip MCU collects the battery voltage signal in real time. When the battery voltage reaches the charging cut-off voltage, the charging control chip MCU changes the output pulse signal and drives the MOSFET tube to turn off, that is, the charging current does not pass through this single battery, thereby preventing the battery from being overcharged, and solving the problem of voltage inconsistency when the lithium-sulfur battery pack is charged in series, thereby increasing the overall charging capacity of the battery pack and greatly improving the service life of the battery pack.CN108551260A discloses a power management circuit and a power management board for a small and medium-sized unmanned aerial vehicle development board, wherein the power management circuit includes a toggle switch, a filter circuit, a voltage conversion module, a voltage stabilizing circuit and a resistor voltage divider circuit, wherein the toggle switch is arranged between the power input terminal and the filter circuit, and the voltage stabilizing circuit is arranged between the voltage conversion module and the resistor voltage divider circuit, and the voltage conversion module is a power converter chip having one to five pins, wherein the first pin is grounded, the fourth pin is connected to the first capacitor, the fifth pin is connected to the input voltage terminal, the third pin is a switch node for providing power to the output, the third pin is connected to the voltage stabilizing circuit and provides power output, and the second pin is connected to the resistor voltage divider circuit to detect the output voltage and adjust it. The present invention adopts a multi-channel design to centrally solve the power distribution and voltage stabilizing output problems of each development board of the unmanned aerial vehicle.

[0005] Although there are many studies on lithium-ion battery modules, the electrochemical characteristics of lithium-sulfur batteries are different from those of traditional lithium-ion batteries, and the voltage platform of lithium-sulfur batteries is relatively special. Its charge and discharge cut-off voltage is completely different from that of lithium-ion batteries. The system control methods currently used in traditional lithium-ion batteries on the market are difficult to directly transfer to lithium-sulfur batteries, which has caused great obstacles to the promotion and large-scale application of lithium-sulfur batteries. Therefore, in order to effectively promote the commercial application of lithium-sulfur batteries and replace traditional lithium-ion batteries, it is necessary to develop a lithium-sulfur battery system with constant voltage output that can be suitable for a variety of application scenarios. Summary of the invention

[0006] The present invention aims to overcome the deficiencies in the prior art and provide a lithium-sulfur battery system with a constant voltage output. The lithium-sulfur battery is used as a power source and combined with a specific circuit integration scheme, so as to maintain a stable lithium-sulfur battery voltage output, effectively overcoming the problem that the existing lithium-sulfur battery has a wide output voltage range and cannot meet the demand for stable voltage electrical appliances, and can effectively promote the commercial application of lithium-sulfur batteries and realize the replacement of traditional lithium-ion batteries.

[0007] To achieve the above-mentioned purpose of the present invention, the first aspect of the present invention provides a lithium-sulfur battery system with a constant voltage output, including at least one lithium-sulfur battery group, each lithium-sulfur battery group is connected to a DC / DC converter for voltage stabilization and then connected in series and / or in parallel, the lithium-sulfur battery group includes a box and at least one lithium-sulfur battery soft-pack cell monomer arranged in the box, each lithium-sulfur battery soft-pack cell monomer is connected to a DC / DC converter for voltage stabilization, and the lithium-sulfur battery soft-pack cell monomers are connected in series and / or in parallel to form the lithium-sulfur battery group. The connection mode of the lithium-sulfur battery group or the lithium-sulfur battery soft-pack cell monomer can be adjusted according to actual needs, such as being set to series and / or parallel. The above-mentioned series or parallel connection mode is completed by connecting the cell pole ears on the lithium-sulfur battery soft-pack cell.

[0008] As a preferred technical solution, the connection mode between the lithium-sulfur battery soft-pack cells in each lithium-sulfur battery pack is the same, and each lithium-sulfur battery pack has the same output voltage.

[0009] As a preferred solution, the lithium-sulfur battery system comprises a lithium-sulfur battery group 1, and the lithium-sulfur battery group 1 is connected to a DC / DC converter 1 for voltage stabilization and serves as an input power source for an electrical device. The lithium-sulfur battery group comprises a box and two lithium-sulfur battery soft-pack cell monomers (11, 12) arranged in the box. The lithium-sulfur battery soft-pack cell monomer 11 is connected to the DC / DC converter 11 for voltage stabilization, and the lithium-sulfur battery soft-pack cell monomer 12 is connected to the DC / DC converter 12 for voltage stabilization. The lithium-sulfur battery soft-pack cell monomer 11 and the lithium-sulfur battery soft-pack cell monomer 12 are connected in series to form the lithium-sulfur battery group 1, and the output voltage of the lithium-sulfur battery system is 5V.

[0010] As a preferred solution, the lithium-sulfur battery system further includes a voltage detection unit and a battery management system. The voltage detection unit detects and obtains the voltage of each lithium-sulfur battery soft-pack cell, and stores the set standard voltage of the lithium-sulfur battery soft-pack cell. According to whether the voltage of the lithium-sulfur battery soft-pack cell is the same as the standard voltage, a signal is input to a DC / DC converter connected to the lithium-sulfur battery soft-pack cell to adjust the cell voltage.

[0011] As a preferred solution, the DC / DC converter is selected from one of a Buck-Boost converter, a Cuk converter, a Sepic converter, a Zeta converter, a Flyback converter, a Push-Pull converter, and a Forward converter.

[0012] As a preferred solution, the four sides of the lithium-sulfur battery soft-pack cell are wrapped in a cell frame, and the cell frame is alternately provided with protrusions and grooves on both sides parallel to the two unwrapped sides of the lithium-sulfur battery soft-pack cell, and two adjacent cell frames are plugged and fixedly connected by one-to-one corresponding grooves and protrusions to form the box. As a further preferred solution, the lithium-sulfur battery pack also includes a cover body, which is arranged on the side where the cell pole ears of the box pass through, and the cover body is mechanically connected to the box body to protect the cell pole ears and the DC / DC converter connected to the cell pole ears. The cell frame can be made of organic materials or metal alloys with good heat dissipation and high strength, such as magnesium alloy and aluminum alloy, which can improve the mechanical strength of the module and effectively reduce weight.

[0013] As a preferred solution, a through hole is provided on the battery cell frame, a through rod is inserted into the through hole and both ends of the through rod are tightened and fixed by nuts.

[0014] As a preferred solution, the groove is in the shape of a cross, a triangle, a quadrilateral, a pentagon, a hexagon, or an ellipse, and the protrusion has a shape matching the groove.

[0015] On the other hand, the present invention provides an application of a lithium-sulfur battery system with a constant voltage output. The lithium-sulfur battery system is applied to a UAV power supply to supply power to electrical equipment on the UAV, so that the UAV can fly stably for a long time when the lithium-sulfur battery with low voltage stability is used as the power source, and the electrical equipment on the UAV can operate normally.

[0016] As a preferred solution, the weight energy density of the lithium-sulfur battery pack in the lithium-sulfur battery system is 400-700Wh / kg, and the volume energy density is 400-700Wh / L. The lithium-sulfur battery system is composed of 3-5 lithium-sulfur battery packs connected in parallel.

[0017] As a preferred solution, a lithium-sulfur battery system with a constant voltage output includes m lithium-sulfur battery groups, wherein the lithium-sulfur battery group 1 is connected to a DC / DC converter 1 for voltage stabilization, the lithium-sulfur battery group 1 includes a box and n lithium-sulfur battery soft-pack cell monomers (11, 12, 13...1n) arranged in the box, each lithium-sulfur battery soft-pack cell monomer 1n is connected to a DC / DC converter 1n for voltage stabilization, and the lithium-sulfur battery soft-pack cell monomers (11, 12, 13...1n) are connected in parallel to form the lithium-sulfur battery group 1; the lithium-sulfur battery group 2 is connected to a DC / DC converter 1 for voltage stabilization. C / DC converter 2 is connected to stabilize voltage..., lithium-sulfur battery pack m is connected to DC / DC converter m to stabilize voltage, lithium-sulfur battery pack m includes a box and n lithium-sulfur battery soft-pack cells (m1, m2...mn) arranged in the box, each lithium-sulfur battery soft-pack cell mn is respectively connected to DC / DC converter mn for voltage stabilization, and lithium-sulfur battery soft-pack cells (m1, m2...mn) are connected in parallel to form the lithium-sulfur battery pack m, and the above m lithium-sulfur battery packs are connected in series, and each lithium-sulfur battery pack has the same output voltage. The lithium-sulfur battery system also includes a voltage detection unit and a battery management system ( Figure 1 (not shown), the voltage detection unit detects and obtains the voltage of each lithium-sulfur battery soft-pack cell, and stores the set standard voltage of the lithium-sulfur battery soft-pack cell. According to whether the voltage of the lithium-sulfur battery soft-pack cell is the same as the standard voltage, a signal is input to the DC / DC converter connected to the lithium-sulfur battery soft-pack cell to adjust the voltage of the cell. The DC / DC converter is a Buck-Boost converter. The four sides of the lithium-sulfur battery soft-pack cell 1 are wrapped in the cell frame 2. The cell frame 2 is provided with a depression for accommodating the four sides or a limit column (for clamping and fixing the lithium-sulfur battery soft-pack cell) on the surface opposite to the four wrapped sides of the lithium-sulfur battery soft-pack cell 1. Figure 1The box body is not shown in the figure), which is used to better accommodate and limit and fix the lithium-sulfur battery cell monomers mn. The two sides of the cell frame 2 that are parallel to the two unwrapped sides of the lithium-sulfur battery soft-pack cell are alternately provided with cross block protrusions 4 and cross-shaped grooves 5. The two adjacent cell frames are plugged and fixedly connected by one-to-one corresponding grooves and protrusions to form the box body. The lithium-sulfur battery pack also includes a cover body, which is arranged on the side where the cell pole ears of the box body pass through. The cover body is mechanically connected to the box body and is used to protect the cell pole ears and the DC / DC converter connected to the cell pole ears. The lithium-sulfur battery system is applied to the power supply of drones to supply power to electrical equipment on drones. Wherein m and n are each independently an integer greater than or equal to 2, and m and n can be the same or different.

[0018] The present invention also provides an application of a lithium-sulfur battery system with a constant voltage output, and the lithium-sulfur battery system is applied to a charging power supply for a smart phone or an LED lamp.

[0019] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: 1. The assembly method of the present invention is simple, and the cost of accessories is low. The lithium-sulfur battery pack adopts a cell frame that wraps the four sides of the lithium-sulfur battery soft-pack cell monomer and is fixed by plugging with protrusions and grooves arranged on the surface thereof. While ensuring the strength of the module, the weight of the module can be effectively reduced, the overall specific energy of the power supply is improved, and the modularization degree is improved from the system, making the manufacturing more convenient.

[0020] 2. The lithium-sulfur battery system of the present invention can ensure stable voltage output under different SOCs of the lithium-sulfur battery, and can also modularly design the lithium-sulfur battery pack or lithium-sulfur battery system according to the actual use scenario, and can dynamically adjust the output voltage of the power supply according to the needs of third-party equipment, effectively improving the promotion and application of lithium-sulfur battery products, effectively promoting the commercial application of lithium-sulfur batteries, and can replace traditional lithium-ion batteries to a certain extent. At the same time, the lithium-sulfur battery system of the present invention can effectively solve the problem of poor power supply voltage stability caused by lithium-sulfur battery voltage fluctuations, so that it can adapt to the needs of more electronic equipment and provide stable power supply for these devices. Not only improve the working efficiency and stability of the equipment, but also extend the service life of the equipment to avoid damage to electronic components caused by voltage fluctuations.

[0021] 3. The lithium-sulfur battery system of the present invention has low requirements on the performance of lithium-sulfur batteries, effectively reducing the cost of the battery pack system. In addition, each battery pack is independent of each other, has good stability, a simple overall structure, is easy to implement, and has high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of a lithium-sulfur battery system with constant voltage output according to the present invention; Figure 2 It is a structural schematic diagram of the lithium-sulfur battery pack of the present invention; Explanation of the reference numerals: 1. lithium-sulfur battery soft-pack cell; 2. cell frame; 3. cell ear; 4. protrusion; 5. groove. DETAILED DESCRIPTION

[0023] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention are further described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0024] It should be noted that the reference to "embodiment" in this document means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0025] The experimental methods in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples are commercially available unless otherwise specified.

[0026] Example 1 A lithium-sulfur battery system with a constant voltage output comprises three lithium-sulfur battery groups, wherein the lithium-sulfur battery group 1 is connected to a DC / DC converter 1 for voltage stabilization, the lithium-sulfur battery group 1 comprises a box and at least two lithium-sulfur battery soft-packed cell monomers (11, 12) arranged in the box, the lithium-sulfur battery soft-packed cell monomer 11 is connected to the DC / DC converter 11 for voltage stabilization, the lithium-sulfur battery soft-packed cell monomer 12 is connected to the DC / DC converter 12 for voltage stabilization, the lithium-sulfur battery soft-packed cell monomers 11, 12 are connected in series to form the lithium-sulfur battery group 1; the lithium-sulfur battery group 2 is connected to the DC / DC converter 2 for voltage stabilization, the lithium-sulfur battery group 2 comprises a box and two lithium-sulfur battery soft-packed cell monomers (21, 22) arranged in the box, the lithium-sulfur battery soft-packed cell monomer 21 is connected to the DC / DC converter 21 for voltage stabilization, the lithium-sulfur battery soft-packed cell monomer 22 is connected to the DC / DC converter 22 for voltage stabilization, the lithium-sulfur battery soft-packed cell monomer 21 and 22 are connected in series to form the lithium-sulfur battery group 2; the lithium-sulfur battery group 3 is connected to the DC / DC converter 3 for voltage stabilization, the lithium-sulfur battery group 3 includes a box and two lithium-sulfur battery soft-pack cell monomers (31, 32) arranged in the box, the lithium-sulfur battery soft-pack cell monomer 31 is connected to the DC / DC converter 31 for voltage stabilization, the lithium-sulfur battery soft-pack cell monomer 32 is connected to the DC / DC converter 32 for voltage stabilization, and the lithium-sulfur battery soft-pack cell monomers 31 and 32 are connected in series to form the lithium-sulfur battery group 3; the lithium-sulfur battery system also includes a voltage detection unit and a battery management system, the voltage detection unit detects and obtains the voltage of each lithium-sulfur battery soft-pack cell monomer, and stores the set lithium-sulfur battery soft-pack cell monomer standard voltage, and inputs a signal to the DC / DC converter connected to the lithium-sulfur battery soft-pack cell monomer according to whether the lithium-sulfur battery soft-pack cell monomer voltage is the same as the standard voltage, and performs cell monomer voltage stabilization adjustment. The DC / DC converter is a Buck-Boost converter. The four sides of the lithium-sulfur battery soft-pack cell 1 are wrapped in the cell frame 2. The cell frame 2 is alternately provided with triangular protrusions 4 and triangular grooves 5 on the two sides parallel to the two unwrapped sides of the lithium-sulfur battery soft-pack cell. Two adjacent cell frames are connected by plugging and fixing through one-to-one corresponding grooves and protrusions to form the box. The cell frame is provided with a through hole, and a through rod is inserted into the through hole and the two ends of the through rod are tightened and fixed by nuts. The lithium-sulfur battery system is applied to the power supply of drones to supply power to the electrical equipment on the drones. The weight energy density of the lithium-sulfur battery pack in the lithium-sulfur battery system is 500Wh / kg, and the volume energy density is 600Wh / L.

[0027] Example 2 A lithium-sulfur battery system with a constant voltage output is composed of a lithium-sulfur battery pack 1, the lithium-sulfur battery pack 1 is connected to a DC / DC converter 1 for voltage stabilization, the lithium-sulfur battery pack 1 comprises a box and three lithium-sulfur battery soft-pack cell monomers (11, 12, 13) arranged in the box, the lithium-sulfur battery soft-pack cell monomer 11 is connected to the DC / DC converter 11 for voltage stabilization, the lithium-sulfur battery soft-pack cell monomer 12 is connected to the DC / DC converter 12 for voltage stabilization, the lithium-sulfur battery soft-pack cell monomer 13 is connected to the DC / DC converter 13 for voltage stabilization, and the lithium-sulfur battery soft-pack cell monomer 14 is connected to the DC / DC converter 14 for voltage stabilization. The battery soft-pack cell monomers 11 and 12 are connected in series and connected in parallel with the lithium-sulfur battery soft-pack cell monomer 13 to form the lithium-sulfur battery group 1; the lithium-sulfur battery system also includes a voltage detection unit and a battery management system, the voltage detection unit detects and obtains the voltage of each lithium-sulfur battery soft-pack cell monomer, and stores the set standard voltage of the lithium-sulfur battery soft-pack cell monomer, and inputs a signal to the DC / DC converter connected to the lithium-sulfur battery soft-pack cell monomer according to whether the voltage of the lithium-sulfur battery soft-pack cell monomer is the same as the standard voltage, and performs voltage regulation of the cell monomer. The DC / DC converter is a Buck-Boost converter. The four sides of the lithium-sulfur battery soft-pack cell monomer 1 are wrapped in the cell frame 2, and the cell frame 2 is alternately provided with triangular protrusions 4 and triangular grooves 5 on the two side surfaces parallel to the two unwrapped surfaces of the lithium-sulfur battery soft-pack cell, and the two adjacent cell frames are plugged and fixedly connected by one-to-one corresponding grooves and protrusions to form the box, and the lithium-sulfur battery system is applied to the LED lamp power supply.

[0028] The above is a detailed introduction to a lithium-sulfur battery system with a constant voltage output and its application. The above content is a further detailed description of the present invention in combination with a specific preferred embodiment, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, its architecture can be flexible and can derive a series of products. Just making a few simple deductions or substitutions should be regarded as belonging to the scope of patent protection of the present invention determined by the submitted claims.

Claims

1. A lithium-sulfur battery system with constant voltage output, comprising at least one lithium-sulfur battery pack, each lithium-sulfur battery pack being connected to a DC / DC converter for voltage stabilization and then connected in series and / or in parallel, characterized in that: The lithium-sulfur battery pack includes a box body and at least one lithium-sulfur battery soft-pack cell monomer arranged in the box body, each lithium-sulfur battery soft-pack cell monomer is connected to a DC / DC converter for voltage stabilization, and the lithium-sulfur battery soft-pack cell monomers are connected in series and / or in parallel to form the lithium-sulfur battery pack.

2. The lithium-sulfur battery system with constant voltage output according to claim 1, characterized in that: The connection mode between the lithium-sulfur battery soft-pack cell monomers in each lithium-sulfur battery pack is the same, and each lithium-sulfur battery pack has the same output voltage.

3. The lithium-sulfur battery system with constant voltage output according to claim 1, characterized in that: The lithium-sulfur battery system also includes a voltage detection unit and a battery management system. The voltage detection unit detects and obtains the voltage of each lithium-sulfur battery soft-pack cell monomer, and stores the set standard voltage of the lithium-sulfur battery soft-pack cell monomer. According to whether the voltage of the lithium-sulfur battery soft-pack cell monomer is the same as the standard voltage, a signal is input to a DC / DC converter connected to the lithium-sulfur battery soft-pack cell monomer to perform voltage regulation and adjustment of the cell monomer voltage.

4. The lithium-sulfur battery system with constant voltage output according to claim 1, characterized in that: The DC / DC converter is selected from one of a Buck-Boost converter, a Cuk converter, a Sepic converter, a Zeta converter, a Flyback converter, a Push-Pull converter, and a Forward converter.

5. The lithium-sulfur battery system with constant voltage output according to claim 1, characterized in that: The four side surfaces of the lithium-sulfur battery soft-pack cell monomer are wrapped in a cell frame, and protrusions and grooves are alternately arranged on two side surfaces of the cell frame parallel to the two unwrapped surfaces of the lithium-sulfur battery soft-pack cell, and two adjacent cell frames are plugged and fixedly connected by one-to-one corresponding grooves and protrusions to form the box body.

6. The lithium-sulfur battery system with constant voltage output according to claim 5, characterized in that: A through hole is arranged on the battery core frame, a through rod is inserted into the through hole and the two ends of the through rod are tightened and fixed by nuts.

7. The lithium-sulfur battery system with constant voltage output according to claim 5, characterized in that: The groove is in the shape of a cross, a triangle, a quadrilateral, a pentagon, a hexagon, or an ellipse, and the protrusion has a shape matching the groove.

8. An application of a lithium-sulfur battery system with constant voltage output according to any one of claims 1 to 7, characterized in that: The lithium-sulfur battery system is used in drone power supply to supply power to the electrical equipment on the drone.

9. The use according to claim 8, characterized in that: The weight energy density of the lithium-sulfur battery group in the lithium-sulfur battery system is 400-700Wh / kg, and the volume energy density is 400-700Wh / L. The lithium-sulfur battery system is composed of 3-5 lithium-sulfur battery groups connected in parallel.

10. An application of a lithium-sulfur battery system with constant voltage output according to any one of claims 1 to 7, characterized in that: The lithium-sulfur battery system is used as a charging power source for smartphones or LED lights.

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