A semi-solid high-voltage hybrid energy storage device and a preparation method thereof

Abstract

The application discloses a kind of semi-solid high-pressure mixed energy storage devices and preparation method thereof, belong to electrochemical energy storage device technical field.The energy storage device uses boron nitride modified PVDF / PEO gel polymer composite electrolyte to replace traditional liquid electrolyte, completely solve the problem of leakage;Through double-sided heteropolar composite electrode and diaphragm alternately laminated 50~380 layer internal series structure, directly realize 800V above high voltage direct output.Its preparation method uses vacuum infiltration+gradient curing process, perfect reuse S01-S03 complete set of core technology, without adding new equipment.The whole package energy density can reach 55~60Wh / kg, operation safety is greatly improved, cycle life is greater than or equal to 120000 times, perfect adaptation to high safety requirement of power grid energy storage, industrial standby and other scenes.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage device and manufacturing technology, specifically relating to an 800V and above internal multilayer series direct output semi-solid high voltage hybrid energy storage device and its preparation method. Background Technology

[0002] Semi-solid-state energy storage technology combines the high ionic conductivity of liquid batteries with the high safety of solid-state batteries, and is considered a core technological solution to address the leakage and safety issues of traditional liquid energy storage devices. However, existing semi-solid-state energy storage technologies suffer from the following fatal flaws:

[0003] 1. Severely unbalanced application areas: More than 90% of semi-solid-state patents are concentrated in the field of lithium-ion batteries, with very few semi-solid-state patents for supercapacitors / hybrid energy storage, and a complete lack of high-voltage series scenarios;

[0004] 2. Incomplete semi-solidification: Existing solutions still contain 20% to 50% free-flowing liquid electrolyte, and the risks of leakage and thermal runaway still exist;

[0005] 3. No high-voltage adaptation design: It cannot be adapted to high-voltage scenarios above 800V, and the internal multi-layer series connection will lead to electrolyte decomposition and interface failure;

[0006] 4. Poor process compatibility: It requires the addition of dedicated solid electrolyte coating and hot pressing equipment, with modification costs reaching tens of millions of yuan, making rapid mass production impossible.

[0007] Currently, there are no patents worldwide that combine gel polymer composite electrolytes with the core structure of "double-sided heteropolar current collectors + lossless stacking + edge full-encapsulation insulation". Therefore, there is an urgent need to develop corresponding semi-solid high-voltage hybrid energy storage devices and their preparation methods. Summary of the Invention

[0008] To address the aforementioned deficiencies in existing technologies, the present invention aims to provide a semi-solid high-voltage hybrid energy storage device and its preparation method. By modifying the gel electrolyte with boron nitride, the leakage problem is completely solved, and a high voltage of over 800V is directly output through an internal multi-layer series structure, perfectly reusing the existing complete set of core manufacturing processes.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] First aspect: Energy storage device technology solutions

[0011] A semi-solid high-voltage hybrid energy storage device includes a multilayer series-connected cell body, a dual-sided heterodyne composite electrode, a gel polymer composite electrolyte, and an edge-encapsulated insulating layer.

[0012] The dual-sided heteropolar composite electrode includes a metal-based composite copper-aluminum foil current collector, a carbon nanotube anchoring layer, and a doped porous carbon active layer. One side of the current collector is coated with a copper layer containing a nitrogen-doped hard carbon negative electrode, and the other side is coated with an aluminum layer containing a boron-doped activated carbon positive electrode, forming a single-foil dual-unit series structure. The multilayer series cell body is formed by alternating stacking of dual-sided heteropolar composite electrodes and separators, with 50 to 380 layers. The gel polymer composite electrolyte fills the pores of the electrodes and separators. The edge-encapsulated insulating layer covers the periphery of the multilayer series cell body.

[0013] Furthermore, the carbon nanotube anchoring layer increases the bonding force between the active layer and the current collector to ≥8 N / cm, and reduces the interfacial impedance by more than 50%; the ionic conductivity of the boron nitride-modified PVDF / PEO composite gel electrolyte is improved. It has a thermal decomposition temperature of ≥300℃ and combines high ionic conductivity with excellent thermal stability.

[0014] Furthermore, an insulating edge area of ​​1.5~3mm is reserved around the electrodes, which is perfectly compatible with SO2 non-destructive lamination and SO3 edge full encapsulation processes, and is 100% compatible with existing production lines.

[0015] Second aspect: Preparation method and technical solution

[0016] A method for fabricating a semi-solid high-voltage hybrid energy storage device includes the following steps:

[0017] S1 electrode preparation: A double-sided heterodyne-doped porous carbon composite electrode was prepared using the S06 method. The copper layer side was a nitrogen-doped hard carbon negative electrode, and the aluminum layer side was a boron-doped activated carbon positive electrode.

[0018] S2 Non-destructive Lamination: Employing the S02 non-destructive transfer and positioning lamination method, the composite electrode and diaphragm are alternately laminated. During the lamination process, only the insulating edge area of ​​the electrode is supported, and the active layer is not in contact throughout the entire process, ensuring high positioning accuracy. This forms a 50-380 layer internal series-connected battery cell body;

[0019] S3 Gel Electrolyte Impregnation and Curing: Boron nitride modified PVDF / PEO gel precursor is injected under a vacuum of -0.09MPa and impregnated for 3 hours. Then, a gradient curing process is adopted, which involves holding at 60℃ for 2 hours, 80℃ for 2 hours, and 120℃ for 4 hours, to form a semi-solid electrolyte.

[0020] S4 Insulation Packaging: The multilayer series cell body is packaged using the edge full-encapsulation insulation process of S03 to obtain the finished energy storage device.

[0021] Compared with the prior art, the present invention has the following outstanding advantages:

[0022] 1. World's first high-voltage series semi-solid hybrid energy storage: For the first time, semi-solid technology is combined with an internal multi-layer high-voltage series structure to directly achieve high voltage output of over 800V;

[0023] 2. Completely eliminates the risk of leakage: There is no free-flowing liquid electrolyte, which fundamentally solves the leakage problem of energy storage devices and improves operational safety by more than 10 times;

[0024] 3. Excellent thermal stability: The thermal decomposition temperature of boron nitride modified gel electrolyte is ≥300℃, with no risk of thermal runaway. Even if punctured or short-circuited, it will not catch fire or explode.

[0025] 4. Fully compatible with the process: 100% compatible with the complete manufacturing process of S01-S06, requiring no additional equipment, and can be directly mass-produced on existing supercapacitor production lines;

[0026] 5. Long cycle life: Cycle life ≥ 120,000 cycles, which is more than 6 times that of lithium iron phosphate batteries, and the total life cycle cost is extremely low. Attached Figure Description

[0027] Figure 1 is a schematic cross-sectional view of the dual-sided heteropolar composite electrode of the present invention;

[0028] Figure 2 is a schematic diagram of the planar structure of the dual-sided heteropolar composite electrode of the present invention;

[0029] Figure 3 is a schematic diagram of the overall structure of the semi-solid high-voltage hybrid energy storage device of the present invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1 - Metal-based composite copper-aluminum foil current collector, 2 - Copper layer, 3 - Aluminum layer, 4 - Carbon nano-anchoring layer, 5 - Nitrogen-doped hard carbon negative electrode active layer, 6 - Boron-doped activated carbon positive electrode active layer, 7 - Insulating edge area, 8 - Electrode active area, 9 - Multilayer series cell body, 10 - Double-sided heterogeneous composite electrode, 11 - Separator, 12 - Edge fully encapsulated insulating layer, 13 - Liquid injection hole. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to specific embodiments.

[0033] Example 1

[0034] The semi-solid high-voltage hybrid energy storage device described in this embodiment adopts a 100-layer internal series structure and has a rated operating voltage of 350V.

[0035] The preparation method is as follows:

[0036] 1. Electrode fabrication: A 20μm thick copper-aluminum composite foil current collector is used, with 80nm thick carbon nanotube anchoring layers coated on both sides; a 100μm thick nitrogen-doped hard carbon anode is coated on the copper layer side, and a 120μm thick boron-doped activated carbon cathode is coated on the aluminum layer side; a 2mm wide insulating edge area is reserved around the electrode.

[0037] 2. Non-destructive lamination: Using the non-destructive transfer and positioning lamination method of SO2, composite electrodes and separators are alternately laminated to form a 100-layer internal series cell body;

[0038] 3. Gel electrolyte impregnation and curing: Boron nitride modified PVDF / PEO gel precursor was injected under a vacuum of -0.09 MPa and impregnated for 3 hours. Gradient curing;

[0039] 4. Insulation encapsulation: The finished energy storage device is encapsulated using the S03 edge full-encapsulation insulation process.

[0040] Performance testing:

[0041] The energy storage device has a total energy density of 58Wh / kg, a power density of 2kW / kg, a capacity retention rate of 91.2% after 120,000 cycles, and a gas production rate that is 65% lower than that of liquid-mixed energy storage under 3.5V high voltage. There is no leakage or active layer shedding.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A semi-solid-state high-voltage hybrid energy storage device, characterized in that... It includes a multilayer series-connected cell body, dual-sided heterodyne composite electrodes, a gel polymer composite electrolyte, and an edge-encapsulated insulating layer; The dual-sided heterogeneous composite electrode comprises a metal-based composite copper-aluminum foil current collector, a carbon nanotube anchoring layer, and a doped porous carbon active layer. One side of the current collector is coated with a nitrogen-doped hard carbon negative electrode (copper layer) and the other side is coated with a boron-doped activated carbon positive electrode (aluminum layer), forming a single-foil dual-unit series structure. The multilayer series-connected battery cell body is formed by alternating stacking of the dual-sided heteropolar composite electrodes and the separator, with 50 to 380 layers; The gel polymer composite electrolyte fills the pores of the electrodes and the diaphragm; The edge-encapsulated insulation layer covers the perimeter of the multilayer series-connected cell body.

2. The energy storage device according to claim 1, characterized in that... The carbon nanotube anchoring layer is fully coated on both sides of the current collector, with a thickness of 50~100nm, forming a continuous conductive network with the current collector and the active layer.

3. The energy storage device according to claim 1, characterized in that... The gel polymer composite electrolyte is a boron nitride-modified PVDF / PEO composite gel with an ionic conductivity of .

4. The energy storage device according to claim 1, characterized in that... The dual-sided heteropolar composite electrode has a 1.5-3mm wide insulating edge area around it, and the insulating edge area has no active layer and anchoring layer.

5. The energy storage device according to claim 1, characterized in that... The rated operating voltage of the multilayer series-connected battery cell body is ≥800V, and no external module series or parallel connection is required.

6. The energy storage device according to claim 1, characterized in that... The edge-encapsulated insulation layer is a boron nitride-modified flexible insulation layer, which simultaneously achieves insulation and thermal conductivity functions.

7. The energy storage device according to claim 1, characterized in that... The energy storage device has no free-flowing liquid electrolyte, completely eliminating the risk of leakage.

8. The energy storage device according to claim 1, characterized in that... The energy storage device has a cycle life of ≥120,000 cycles and a capacity retention rate of ≥90%.

9. A method for preparing a semi-solid-state high-voltage hybrid energy storage device as described in any one of claims 1-8, characterized in that... This includes the following steps: S1 Electrode Fabrication: A double-sided heteropter-doped porous carbon composite electrode was fabricated using the S06 method; S2 Non-destructive Lamination: Using the S02 non-destructive transfer and positioning lamination method, composite electrodes and separators are alternately laminated to form a multilayer series cell body; S3 Gel Electrolyte Impregnation and Curing: A gel polymer composite electrolyte precursor is injected using a vacuum impregnation process, and a semi-solid electrolyte is formed after gradient curing. S4 Insulation Packaging: The multilayer series cell body is packaged using the S03 edge full-encapsulation insulation process to obtain the finished energy storage device.

10. The preparation method according to claim 9, characterized in that... In step S3, the vacuum degree of vacuum impregnation is -0.08 to -0.1 MPa, the impregnation time is 2 to 4 hours, the gradient curing temperature is 60 to 120°C, and the curing time is 6 to 12 hours.

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