High-safety positive plate and hybrid capacitor

Abstract

The invention relates to the technical field of positive plates, and discloses a high-safety positive plate and a hybrid capacitor, the positive plate comprises a current collector and a positive coating arranged on the current collector, the current collector and the coating are provided with a plurality of vertically corresponding through holes, the diameter of each through hole is 10-1000 [mu] m, and the interval between every two adjacent holes is 100-5000 [mu] m; the positive electrode coating comprises the following raw materials: ternary lithium, capacitor carbon, a conductive agent and a binder. The mechanical performance of the pole piece is reduced by adopting the perforated positive pole piece, and the pole piece is easier to break and cut off short-circuit current between the positive pole and the negative pole when being needled, so that heat production is reduced, and the needling safety performance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of positive electrode sheets, and in particular to a high-safety positive electrode sheet and a hybrid capacitor. Background Art

[0002] Double-layer capacitors store energy because positive and negative ions are adsorbed on the surface between the electrode and the electrolyte, creating a potential difference between the electrodes. No electrochemical reaction occurs during the energy storage process. It is a physical energy storage method with the advantages of fast charging and discharging speed, high power density, and long cycle life. Double-layer capacitors are a widely used energy storage device.

[0003] Hybrid capacitors are supercapacitors that have both double layers and redox reactions in the positive and / or negative electrodes to achieve energy storage. Due to the introduction of redox reactions, their energy density is much higher than that of double-layer capacitors. Lithium-ion capacitors are a type of hybrid capacitor, which is a capacitor whose energy storage process includes both lithium ion insertion / extraction and double-layer adsorption, which is equivalent to introducing lithium ion materials into double-layer capacitors to improve the energy density of double-layer capacitors.

[0004] At present, the mature lithium-ion cathode materials are mainly LiCoO 4 , LiFePO 4 , ternary lithium cathode (LiMO 2 , M is three transition metal elements, usually nickel-cobalt-manganese or nickel-cobalt-aluminum). The ternary lithium positive electrode has a high energy density, but the intrinsic safety of its material is low, and there are certain safety hazards, especially the strict needle puncture safety performance cannot be passed. During the needle puncture, a short circuit occurs inside the capacitor, and the heat generated by the positive aluminum foil-negative electrode short circuit is the most, which is the main heat source leading to thermal runaway. Summary of the invention

[0005] In order to solve the above-mentioned technical problems, the present invention provides a high-safety positive electrode sheet and a hybrid capacitor, which adopts a perforated positive electrode sheet to reduce the mechanical properties of the electrode sheet, making it easier to break when punctured, cutting off the short-circuit current between the positive and negative electrodes, thereby reducing heat generation and improving the safety performance of puncture.

[0006] The purpose of the present invention is achieved through the following technical solutions: In the first aspect, the present invention provides a high-safety positive electrode sheet, which includes a current collector and a positive electrode coating provided on the current collector, and the current collector and the coating are provided with a plurality of upper and lower corresponding through holes, the diameter of the through holes is 10 to 1000 μm, and the interval between adjacent holes is 100 to 5000 μm; the raw materials of the positive electrode coating include ternary lithium, capacitor carbon, a conductive agent and a binder.

[0007] The energy density of batteries is higher than that of capacitors, and the heat generated during the acupuncture process is high. Even with a perforated positive electrode sheet, the safety performance of acupuncture cannot be effectively improved. The present invention adopts a hybrid capacitor, which has a relatively high energy density and can effectively improve the safety performance of acupuncture by using a perforated positive electrode sheet. Among them, the capacitor carbon added to the capacitor can improve the conductivity and reduce the temperature rise during the acupuncture process on the one hand, and on the other hand, no oxygen release reaction occurs during the thermal runaway of acupuncture, and the structure is stable, thereby better improving the safety performance. On this basis, the setting of the through hole on the positive electrode sheet can reduce the mechanical properties of the electrode sheet, making it easier to break when acupunctured, cutting off the short-circuit current between the positive and negative electrodes, thereby reducing heat generation and further improving the safety performance of acupuncture. The parameter setting of the through hole will affect the mechanical properties and safety performance of the positive electrode sheet at the same time. The through hole within a certain range and the buffering effect of the capacitor carbon can enable the positive electrode sheet to obtain suitable mechanical strength while having good acupuncture safety performance.

[0008] Preferably, the diameter of the through-holes is 20 to 100 μm, and the interval between adjacent holes is 500 to 2000 μm.

[0009] Preferably, the thickness of the positive electrode sheet is 50 to 200 μm.

[0010] Preferably, the current collector is carbon-coated aluminum foil, aluminum foil or corroded aluminum foil.

[0011] Preferably, the raw materials of the positive electrode coating include, by mass fraction, 50-80% ternary lithium, 5-40% capacitor carbon, 1-15% conductive agent and 3-10% binder.

[0012] Preferably, the chemical formula of the ternary lithium is LiMO 2 , wherein M is nickel, cobalt, manganese or nickel, cobalt, aluminum.

[0013] Preferably, the capacitor carbon is one or more of activated carbon, mesoporous carbon, and carbon aerogel.

[0014] Preferably, the conductive agent includes one or more of conductive carbon black, Ketjen black, carbon nanotubes, carbon nanofibers and graphene.

[0015] Preferably, the binder includes one or more of SBR, CMC, PTFE, PVDF and PAA.

[0016] In a second aspect, the present invention also provides a hybrid capacitor, comprising a positive electrode sheet and a negative electrode sheet; the positive electrode sheet is the above-mentioned high-safety positive electrode sheet; the negative electrode sheet comprises a current collector and a negative electrode coating provided on the current collector; the negative electrode coating comprises an active substance, and the active substance is soft carbon or hard carbon.

[0017] Preferably, the current collector is carbon-coated copper foil or copper foil.

[0018] Preferably, the negative electrode coating comprises an active material, capacitor carbon, a conductive agent and a binder.

[0019] Preferably, the raw materials of the negative electrode coating include, by mass fraction, 50-90% active material, 5-30% capacitor carbon, 1-10% conductive agent and 3-10% binder.

[0020] Preferably, the capacitor carbon is one or more of activated carbon, mesoporous carbon, and carbon aerogel.

[0021] Preferably, the conductive agent includes one or more of conductive carbon black, Ketjen black, carbon nanotubes, carbon nanofibers and graphene.

[0022] Preferably, the binder includes one or more of SBR, CMC, PTFE, PVDF and PAA.

[0023] Preferably, the hybrid capacitor further comprises a diaphragm and an electrolyte disposed between the positive electrode sheet and the negative electrode sheet.

[0024] Preferably, the electrolyte comprises an electrolyte salt, an organic solvent and an additive; the electrolyte salt comprises a lithium salt and a tetrafluoroborate; and the organic solvent is one or more of a carbonate solvent and an ether solvent.

[0025] Preferably, the material of the diaphragm includes one or more of PP, PE, PET, cellulose, aramid, spandex, polyester, polyimide and polyamide.

[0026] Compared with the prior art, the present invention has the following beneficial effects: (1) Hybrid capacitors, which have a relatively high energy density and can effectively improve the safety performance of needle puncture by using a perforated positive electrode; (2) The provision of through holes on the positive electrode sheet can reduce the mechanical properties of the electrode sheet, making it easier to break when punctured, thereby cutting off the short-circuit current between the positive and negative electrodes, thereby reducing heat generation and further improving the safety performance of puncture. The through holes within a certain parameter range combined with the buffering effect of the capacitor carbon can enable the positive electrode sheet to obtain suitable mechanical strength while having good safety performance of puncture. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is described below with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0028] 1. High safety positive electrode The positive electrode sheet includes a current collector and a positive electrode coating on the current collector. The current collector and the coating are provided with a plurality of corresponding through holes, the diameter of the through holes is 10 to 1000 μm, the interval between adjacent holes is 100 to 5000 μm, and the thickness of the positive electrode sheet is 50 to 200 μm.

[0029] The current collector is carbon-coated aluminum foil, aluminum foil or corroded aluminum foil.

[0030] By mass fraction, the raw materials of the positive electrode coating include 50-80% ternary lithium, 5-40% capacitor carbon, 1-15% conductive agent and 3-10% binder. The chemical formula of ternary lithium is LiMO 2 , wherein M is nickel, cobalt, manganese or nickel, cobalt, aluminum. The capacitor carbon is one or more of activated carbon, mesoporous carbon, and carbon aerogel. The conductive agent includes one or more of conductive carbon black, Ketjen black, carbon nanotubes, carbon nanofibers, and graphene. The binder includes one or more of SBR, CMC, PTFE, PVDF, and PAA.

[0031] The method for preparing the positive electrode sheet comprises the following steps: (1) preparing a positive electrode slurry by mixing ternary lithium, capacitor carbon, a conductive agent and a binder according to a proportion; (2) coating the positive electrode slurry on the current collector to form a positive electrode sheet; (3) The coated positive electrode sheet is perforated to obtain a high-safety positive electrode sheet.

[0032] 2. Hybrid capacitor The hybrid capacitor includes a positive electrode, a separator, a negative electrode, and an electrolyte filled between them.

[0033] The positive electrode sheet is the above-mentioned high-safety positive electrode sheet.

[0034] The negative electrode sheet includes a current collector and a negative electrode coating provided on the current collector. The current collector is a carbon-coated copper foil or a copper foil. By mass fraction, the raw materials of the negative electrode coating include 50-90% active material, 5-30% capacitor carbon, 1-10% conductive agent and 3-10% binder. The active material is soft carbon or hard carbon. The capacitor carbon is one or more of activated carbon, mesoporous carbon, and carbon aerogel. The conductive agent includes one or more of conductive carbon black, Ketjen black, carbon nanotubes, carbon nanofibers and graphene. The binder includes one or more of SBR, CMC, PTFE, PVDF and PAA.

[0035] The material of the separator includes one or more of PP, PE, PET, cellulose, aramid, spandex, polyester, polyimide and polyamide.

[0036] The electrolyte includes electrolyte salt, organic solvent and additives. The electrolyte salt includes lithium salt and tetrafluoroborate. The lithium salt can be LiPF6 , LiBF 4 、LiClO 4 or LIFSI, the tetrafluoroborate can be TEABF 4 DMPBF 4 or SBPBF 4 The organic solvent is one or more of a carbonate solvent and an ether solvent. The additive is a film-forming additive (VC, FEC or VEC) or a flame retardant additive (TMP or TPP) and the like.

[0037] The preparation method of the hybrid capacitor comprises the following steps: (1) rolling and cutting the positive electrode sheet and the negative electrode sheet; (2) Assembling the positive electrode, the negative electrode and the separator; (3) After assembly, drying, liquid injection and sealing are performed to obtain a hybrid capacitor; (4) Conduct aging and electrical performance tests.

[0038] Example 1 1. High safety positive electrode The positive electrode sheet includes a current collector (aluminum foil) and a positive electrode coating on the current collector, and the current collector and the coating are provided with a plurality of corresponding through holes. By mass fraction, the raw materials of the positive electrode coating include ternary lithium (lithium nickel cobalt manganese oxide) 70%, capacitor carbon (activated carbon) 20%, conductive agent (conductive carbon black SP) 6% and binder (PVDF) 4%.

[0039] The method for preparing the positive electrode sheet comprises the following steps: (1) preparing a positive electrode slurry by mixing ternary lithium, capacitor carbon, a conductive agent and a binder according to a proportion; (2) coating the positive electrode slurry on the current collector to form a positive electrode sheet; (3) The coated positive electrode sheet is perforated, the diameter of the through hole is 20 μm, the interval between adjacent holes is 500 μm, and a high-safety positive electrode sheet is obtained. The thickness of the positive electrode sheet is 100 μm.

[0040] 2. Hybrid capacitor The hybrid capacitor includes a positive electrode, a separator (cellulose) and a negative electrode, and an electrolyte filled therebetween. The positive electrode is the above-mentioned high-safety positive electrode. The negative electrode includes a current collector (copper foil) and a negative electrode coating provided on the current collector. By mass fraction, the raw materials of the negative electrode coating include 80% active material (soft carbon), 10% capacitor carbon (activated carbon), 5% conductive agent (conductive carbon black SP) and 5% binder (CMC 1.5% and SBR 3.5%). The electrolyte includes an electrolyte salt (LiPF 6 and TEABF 4), organic solvent (ethylene carbonate) and additive (ethylene ethylene carbonate VEC), among which LiPF 6 The concentration is 1 mol / L, TEABF 4 It is 0.2 mol / L, and the amount of additive added is 7.5% of the electrolyte mass.

[0041] Example 2 1. High safety positive electrode The positive electrode sheet includes a current collector (aluminum foil) and a positive electrode coating on the current collector, and the current collector and the coating are provided with a plurality of corresponding through holes. By mass fraction, the raw materials of the positive electrode coating include ternary lithium (lithium nickel cobalt manganese oxide) 75%, capacitor carbon (activated carbon) 15%, conductive agent (conductive carbon black SP) 5% and binder (PVDF) 5%.

[0042] The method for preparing the positive electrode sheet comprises the following steps: (1) preparing a positive electrode slurry by mixing ternary lithium, capacitor carbon, a conductive agent and a binder according to a proportion; (2) coating the positive electrode slurry on the current collector to form a positive electrode sheet; (3) The coated positive electrode sheet is perforated, the diameter of the through hole is 20 μm, the interval between adjacent holes is 500 μm, and a high-safety positive electrode sheet is obtained. The thickness of the positive electrode sheet is 100 μm.

[0043] 2. Hybrid capacitor The hybrid capacitor includes a positive electrode, a separator (cellulose) and a negative electrode, and an electrolyte filled therebetween. The positive electrode is the above-mentioned high-safety positive electrode. The negative electrode includes a current collector (copper foil) and a negative electrode coating provided on the current collector. By mass fraction, the raw materials of the negative electrode coating include 80% active material (soft carbon), 10% capacitor carbon (activated carbon), 5% conductive agent (conductive carbon black SP) and 5% binder (CMC 1.5% and SBR 3.5%). The electrolyte includes an electrolyte salt (LiPF 6 and TEABF 4 ), organic solvent (ethylene carbonate) and additive (ethylene ethylene carbonate VEC), among which LiPF 6 The concentration is 1 mol / L, TEABF 4 It is 0.2 mol / L, and the amount of additive added is 7.5% of the electrolyte mass.

[0044] Example 3 1. High safety positive electrode The positive electrode sheet includes a current collector (aluminum foil) and a positive electrode coating on the current collector, and the current collector and the coating are provided with a plurality of corresponding through holes. By mass fraction, the raw materials of the positive electrode coating include ternary lithium (lithium nickel cobalt manganese oxide) 70%, capacitor carbon (activated carbon) 20%, conductive agent (conductive carbon black SP) 6% and binder (PVDF) 4%.

[0045] The method for preparing the positive electrode sheet comprises the following steps: (1) preparing a positive electrode slurry by mixing ternary lithium, capacitor carbon, a conductive agent and a binder according to a proportion; (2) coating the positive electrode slurry on the current collector to form a positive electrode sheet; (3) The coated positive electrode sheet is perforated, the diameter of the through hole is 40 μm, the interval between adjacent holes is 800 μm, and a high-safety positive electrode sheet is obtained. The thickness of the positive electrode sheet is 100 μm.

[0046] 2. Hybrid capacitor The hybrid capacitor includes a positive electrode, a separator (cellulose) and a negative electrode, and an electrolyte filled therebetween. The positive electrode is the above-mentioned high-safety positive electrode. The negative electrode includes a current collector (copper foil) and a negative electrode coating provided on the current collector. By mass fraction, the raw materials of the negative electrode coating include 80% active material (soft carbon), 10% capacitor carbon (activated carbon), 5% conductive agent (conductive carbon black SP) and 5% binder (CMC 1.5% and SBR 3.5%). The electrolyte includes an electrolyte salt (LiPF 6 and TEABF 4 ), organic solvent (ethylene carbonate) and additive (ethylene ethylene carbonate VEC), among which LiPF 6 The concentration is 1 mol / L, TEABF 4 It is 0.2 mol / L, and the amount of additive added is 7.5% of the electrolyte mass.

[0047] Example 4 1. High safety positive electrode The positive electrode sheet includes a current collector (aluminum foil) and a positive electrode coating on the current collector, and the current collector and the coating are provided with a plurality of corresponding through holes. By mass fraction, the raw materials of the positive electrode coating include ternary lithium (lithium nickel cobalt manganese oxide) 70%, capacitor carbon (activated carbon) 20%, conductive agent (conductive carbon black SP) 6% and binder (PVDF) 4%.

[0048] The method for preparing the positive electrode sheet comprises the following steps: (1) preparing a positive electrode slurry by mixing ternary lithium, capacitor carbon, a conductive agent and a binder according to a proportion; (2) coating the positive electrode slurry on the current collector to form a positive electrode sheet; (3) The coated positive electrode sheet is perforated, the diameter of the through hole is 100 μm, the interval between adjacent holes is 1500 μm, and a high-safety positive electrode sheet is obtained. The thickness of the positive electrode sheet is 100 μm.

[0049] 2. Hybrid capacitor The hybrid capacitor includes a positive electrode, a separator (cellulose) and a negative electrode, and an electrolyte filled therebetween. The positive electrode is the above-mentioned high-safety positive electrode. The negative electrode includes a current collector (copper foil) and a negative electrode coating provided on the current collector. By mass fraction, the raw materials of the negative electrode coating include 80% active material (soft carbon), 10% capacitor carbon (activated carbon), 5% conductive agent (conductive carbon black SP) and 5% binder (CMC 1.5% and SBR 3.5%). The electrolyte includes an electrolyte salt (LiPF 6 and TEABF 4 ), organic solvent (ethylene carbonate) and additive (ethylene ethylene carbonate VEC), among which LiPF 6 The concentration is 1 mol / L, TEABF 4 It is 0.2 mol / L, and the amount of additive added is 7.5% of the electrolyte mass.

[0050] Comparative Example 1 1. Positive electrode The positive electrode sheet includes a current collector (aluminum foil) and a positive electrode coating on the current collector, and the current collector and the coating are not perforated. By mass fraction, the raw materials of the positive electrode coating include ternary lithium (lithium nickel cobalt manganese oxide) 70%, capacitor carbon (activated carbon) 20%, conductive agent (conductive carbon black SP) 6% and binder (PVDF) 4%.

[0051] The method for preparing the positive electrode sheet comprises the following steps: (1) preparing a positive electrode slurry by mixing ternary lithium, capacitor carbon, a conductive agent and a binder according to a proportion; (2) The positive electrode slurry is coated on the current collector to form a positive electrode sheet, and the thickness of the positive electrode sheet is 100 μm.

[0052] 2. Hybrid capacitor The hybrid capacitor includes a positive electrode, a separator (cellulose) and a negative electrode, and an electrolyte filled therebetween. The positive electrode is the positive electrode prepared as described above. The negative electrode includes a current collector (copper foil) and a negative electrode coating provided on the current collector. By mass fraction, the raw materials of the negative electrode coating include 80% active material (soft carbon), 10% capacitor carbon (activated carbon), 5% conductive agent (conductive carbon black SP) and 5% binder (CMC 1.5% and SBR 3.5%). The electrolyte includes an electrolyte salt (LiPF 6 and TEABF 4), organic solvent (ethylene carbonate) and additive (ethylene ethylene carbonate VEC), among which LiPF 6 The concentration is 1 mol / L, TEABF 4 It is 0.2 mol / L, and the amount of additive added is 7.5% of the electrolyte mass.

[0053] Comparative Example 2 1. Positive electrode The positive electrode sheet includes a current collector (aluminum foil) and a positive electrode coating on the current collector, and the current collector and the coating are provided with a plurality of corresponding through holes. By mass fraction, the raw materials of the positive electrode coating include ternary lithium (lithium nickel cobalt manganese oxide) 70%, capacitor carbon (activated carbon) 20%, conductive agent (conductive carbon black SP) 6% and binder (PVDF) 4%.

[0054] The method for preparing the positive electrode sheet comprises the following steps: (1) preparing a positive electrode slurry by mixing ternary lithium, capacitor carbon, a conductive agent and a binder according to a proportion; (2) coating the positive electrode slurry on the current collector to form a positive electrode sheet; (3) The coated positive electrode sheet is perforated, the diameter of the through hole is 5 μm, the interval between adjacent holes is 1000 μm, and the positive electrode sheet is manufactured. The thickness of the positive electrode sheet is 100 μm.

[0055] 2. Hybrid capacitor The hybrid capacitor includes a positive electrode, a separator (cellulose) and a negative electrode, and an electrolyte filled therebetween. The positive electrode is the positive electrode prepared as described above. The negative electrode includes a current collector (copper foil) and a negative electrode coating provided on the current collector. By mass fraction, the raw materials of the negative electrode coating include 80% active material (soft carbon), 10% capacitor carbon (activated carbon), 5% conductive agent (conductive carbon black SP) and 5% binder (CMC 1.5% and SBR 3.5%). The electrolyte includes an electrolyte salt (LiPF 6 and TEABF 4 ), organic solvent (ethylene carbonate) and additive (ethylene ethylene carbonate VEC), among which LiPF 6 The concentration is 1 mol / L, TEABF 4 It is 0.2 mol / L, and the amount of additive added is 7.5% of the electrolyte mass.

[0056] Comparative Example 3 1. Positive electrode The positive electrode sheet includes a current collector (aluminum foil) and a positive electrode coating on the current collector, and the current collector and the coating are provided with a plurality of corresponding through holes. By mass fraction, the raw materials of the positive electrode coating include ternary lithium (lithium nickel cobalt manganese oxide) 70%, capacitor carbon (activated carbon) 20%, conductive agent (conductive carbon black SP) 6% and binder (PVDF) 4%.

[0057] The method for preparing the positive electrode sheet comprises the following steps: (1) preparing a positive electrode slurry by mixing ternary lithium, capacitor carbon, a conductive agent and a binder according to a proportion; (2) coating the positive electrode slurry on the current collector to form a positive electrode sheet; (3) The coated positive electrode sheet was perforated, the diameter of the through hole was 2000 μm, the interval between adjacent holes was 500 μm, and the positive electrode sheet was obtained. The thickness of the positive electrode sheet was 100 μm.

[0058] 2. Hybrid capacitor The hybrid capacitor includes a positive electrode, a separator (cellulose) and a negative electrode, and an electrolyte filled therebetween. The positive electrode is the positive electrode prepared as described above. The negative electrode includes a current collector (copper foil) and a negative electrode coating provided on the current collector. By mass fraction, the raw materials of the negative electrode coating include 80% active material (soft carbon), 10% capacitor carbon (activated carbon), 5% conductive agent (conductive carbon black SP) and 5% binder (CMC 1.5% and SBR 3.5%). The electrolyte includes an electrolyte salt (LiPF 6 and TEABF 4 ), organic solvent (ethylene carbonate) and additive (ethylene ethylene carbonate VEC), among which LiPF 6 The concentration is 1 mol / L, TEABF 4 It is 0.2 mol / L, and the amount of additive added is 7.5% of the electrolyte mass.

[0059] Comparative Example 4 1. Positive electrode The positive electrode sheet includes a current collector (aluminum foil) and a positive electrode coating on the current collector, and the current collector and the coating are provided with a plurality of corresponding through holes. By mass fraction, the raw materials of the positive electrode coating include ternary lithium (lithium nickel cobalt manganese oxide) 90%, conductive agent (conductive carbon black SP) 6% and binder (PVDF) 4%.

[0060] The method for preparing the positive electrode sheet comprises the following steps: (1) preparing a positive electrode slurry by mixing ternary lithium, a conductive agent and a binder according to a ratio; (2) coating the positive electrode slurry on the current collector to form a positive electrode sheet; (3) The coated positive electrode sheet is perforated, the diameter of the through hole is 20 μm, the interval between adjacent holes is 500 μm, and the positive electrode sheet is manufactured. The thickness of the positive electrode sheet is 100 μm.

[0061] 2. Lithium-ion battery The lithium-ion battery includes a positive electrode sheet, a separator (cellulose) and a negative electrode sheet, and an electrolyte filled therebetween. The positive electrode sheet is the positive electrode sheet prepared as described above. The negative electrode sheet includes a current collector (copper foil) and a negative electrode coating provided on the current collector. By mass fraction, the raw materials of the negative electrode coating include 90% active material (graphite), 5% conductive agent (conductive carbon black SP) and 5% binder (CMC 1.5% and SBR 3.5%). The electrolyte includes an electrolyte salt (LiPF 6 ), organic solvent (ethylene carbonate) and additive (ethylene ethylene carbonate VEC), among which LiPF 6 The concentration is 1 mol / L, and the amount of additive added is 7.5% of the electrolyte mass.

[0062] The positive and negative electrodes in Examples 1-4 and Comparative Examples 1-4 were rolled and cut, and the positive and negative electrodes and cellulose separators were wound, assembled, dried, injected, and sealed to produce cylindrical hybrid capacitor / lithium ion batteries with a diameter of 60 mm and a height of 138 mm. The monomers were aged and then subjected to electrical performance tests and needle puncture performance tests.

[0063] Table 1 Performance test results As shown in Table 1, comparing Example 1 with Comparative Example 1, the perforated electrode can improve the acupuncture safety performance of the hybrid capacitor without affecting the energy density. Comparing Example 1 with Comparative Examples 2 and 3, the aperture and spacing of the perforated electrode must be within an appropriate range. If the aperture is too small, it will have no significant effect on improving the acupuncture safety performance. If the aperture is too large, the strength of the electrode will be weakened, affecting the process, while causing material waste and reducing energy density. Comparing Example 1 with Comparative Example 4, Comparative Example 4 is a lithium-ion battery with a high energy density. The heat generated during the acupuncture process is large, and the punching method cannot effectively improve its acupuncture safety performance.

[0064] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the specification of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A high-safety positive electrode sheet, characterized in that: The positive electrode sheet includes a current collector and a positive electrode coating provided on the current collector. The current collector and the coating are provided with a plurality of through holes corresponding to each other from top to bottom. The diameter of the through holes is 10-1000 μm, and the interval between adjacent holes is 100-5000 μm. The raw materials of the positive electrode coating include ternary lithium, capacitor carbon, conductive agent and binder.

2. The high-safety positive electrode sheet according to claim 1, characterized in that: The thickness of the positive electrode sheet is 50-200 μm.

3. The high-safety positive electrode sheet according to claim 1, characterized in that: Calculated by mass fraction, the raw materials of the positive electrode coating include 50-80% ternary lithium, 5-40% capacitor carbon, 1-15% conductive agent and 3-10% binder.

4. The high-safety positive electrode sheet according to claim 1, characterized in that: The chemical formula of the ternary lithium is LiMO2, wherein M is nickel, cobalt, manganese or nickel, cobalt, aluminum.

5. The high-safety positive electrode sheet according to any one of claims 1 to 4, characterized in that: The capacitor carbon is one or more of activated carbon, mesoporous carbon and carbon aerogel.

6. A hybrid capacitor, characterized in that: It comprises a positive electrode sheet and a negative electrode sheet; the positive electrode sheet is a high-safety positive electrode sheet as described in any one of claims 1 to 5; the negative electrode sheet comprises a current collector and a negative electrode coating provided on the current collector; the negative electrode coating comprises an active substance, and the active substance is soft carbon or hard carbon.

7. The hybrid capacitor according to claim 6, characterized in that: The negative electrode coating comprises active material, capacitor carbon, conductive agent and binder.

8. The hybrid capacitor according to claim 7, characterized in that: Calculated by mass fraction, the raw materials of the negative electrode coating include 50-90% active material, 5-30% capacitor carbon, 1-10% conductive agent and 3-10% binder.

9. The hybrid capacitor according to any one of claims 6 to 8, characterized in that: The hybrid capacitor also includes a diaphragm and an electrolyte disposed between the positive electrode sheet and the negative electrode sheet.

10. The hybrid capacitor according to claim 9, characterized in that: The electrolyte includes electrolyte salt, organic solvent and additives; the electrolyte salt includes lithium salt and tetrafluoroborate; the organic solvent is one or more of carbonate solvent and ether solvent.

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