A low internal resistance electrolyte and lithium-ion battery

Abstract

This invention relates to the field of battery technology, specifically to a low internal resistance electrolyte and a lithium-ion battery. The electrolyte comprises the following components: a solvent system composed of fluorocarboxylic acid esters and asymmetric cyclic carbonates, wherein the fluorocarboxylic acid ester is ethyl 2,2-difluoroacetate, and the asymmetric cyclic carbonate is a mixture of fluoroethylene carbonate and vinylene carbonate in a 3:1 mass ratio; a lithium salt composition comprising lithium bis(fluorosulfonyl)imide and lithium difluorooxalate borate, wherein the concentration of lithium bis(fluorosulfonyl)imide is 1.2-1.8 mol / L, and the concentration of lithium difluorooxalate borate is 0.3-0.7 mol / L; a multifunctional additive comprising trithioethylene carbonate, tetrabutylammonium hexafluorophosphate, and 2,6-di-tert-butyl-p-cresol; and a nano-dispersed phase consisting of surface-hydroxylated boron nitride nanosheets with a -OH coverage ≥15%. The lithium-ion battery comprises a frame structure, battery cells, and a protective base; the battery cells adopt a lift-up mounting structure. This achieves the purpose of reducing the internal resistance of the electrolyte and minimizing the hazards caused by electrolyte leakage.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a low internal resistance electrolyte and a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries are widely used in electric vehicles, energy storage systems, consumer electronics, and aerospace due to their high energy density, long cycle life, and lightweight properties. The electrolyte, as the ion transport medium in lithium-ion batteries, directly affects the battery's power output, rate performance, and low-temperature characteristics. Traditional electrolytes typically use a combination of carbonate solvents and LiPF6 lithium salts. However, under high-rate charge / discharge or low-temperature conditions, the ionic conductivity of the electrolyte decreases significantly, leading to a sharp increase in the battery's internal resistance. Increased internal resistance not only reduces energy efficiency but also causes localized overheating, accelerates battery aging, and can even trigger thermal runaway.

[0003] Meanwhile, in battery packs, due to the influence of packaging processes or the battery usage environment, electrolyte leakage can occur in individual battery cells. A single cell's electrolyte leakage can trigger a chain reaction, severely impacting the safety and reliability of the entire system. Currently, the main causes of electrolyte leakage include mechanical abuse, thermal runaway, and long-term aging. Once electrolyte leaks, it can cause short-circuit risks, and the electrolyte itself is corrosive; organic solvents and lithium salts in the electrolyte can corrode metal components, circuit boards, or heat dissipation structures, leading to the spread of thermal runaway. Currently, the industry mainly mitigates the risk of leakage by optimizing battery packaging processes, but this cannot effectively and proactively reduce the damage caused by leakage. Summary of the Invention

[0004] The purpose of this invention is to provide a low internal resistance electrolyte and a lithium-ion battery, so as to reduce the internal resistance of the electrolyte and reduce the hazards caused by electrolyte leakage, thereby solving the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a low internal resistance electrolyte, comprising the following components:

[0006] Solvent system: composed of fluorocarboxylic acid ester and asymmetric cyclic carbonate, wherein the fluorocarboxylic acid ester is ethyl 2,2-difluoroacetate, and the asymmetric cyclic carbonate is a mixture of fluoroethylene carbonate and vinylene carbonate in a 3:1 mass ratio.

[0007] Lithium salt combination: comprising lithium bis(fluorosulfonyl)imide and lithium difluorooxalate borate, wherein the concentration of lithium bis(fluorosulfonyl)imide is 1.2-1.8 mol / L and the concentration of lithium difluorooxalate borate is 0.3-0.7 mol / L;

[0008] Multifunctional additive: Contains ethylene trithiocarbonate, tetrabutylammonium hexafluorophosphate and 2,6-di-tert-butyl-p-cresol;

[0009] Nanodispersed phase: boron nitride nanosheets with surface hydroxylation treatment, and -OH coverage ≥15%.

[0010] Preferably, in the solvent system, ethyl 2,2-difluoroacetate accounts for 30-40% of the total mass of the electrolyte, and fluoroethylene carbonate and vinylene carbonate together account for 20-30%.

[0011] In the multifunctional additive, trithioethylene carbonate accounts for 2-4% of the total mass of the electrolyte, tetrabutylammonium hexafluorophosphate accounts for 1-3%, and 2,6-di-tert-butyl-p-cresol accounts for 0.5-1%.

[0012] The boron nitride nanosheets have a particle size of 50-200 nm, a thickness of ≤5 nm, and a dispersion concentration of 0.3-0.6 wt% in the electrolyte.

[0013] A lithium-ion battery using the low internal resistance electrolyte described above, the battery pack comprising:

[0014] The frame structure consists of a battery base plate, a base, side frames, and a top mount. The base is a frame structure and is arranged and installed on the battery base plate.

[0015] Battery cells are arranged and installed between the base and the top mount;

[0016] The protective base is fixed below the battery base plate. The protective base is equipped with a storage tank to collect leaked electrolyte and provide sinking space for the battery cells.

[0017] The battery cell adopts a lifting installation structure, and the bottom of the battery cell is equipped with a lifting seat with a base block. A support seat is installed in the storage tank through a spring guide rod. The battery cell is supported by the contact between the support seat and the base block. The support seat is kept in the supported state by a floating pin. When the electrolyte leaks, the buoyancy generated can unlock the pin.

[0018] The storage tank is equipped with a sleeve with a movable sealing ring, and the top seat is equipped with a pop-out glue box with a sealing plate. The sleeve and the glue box can be used to seal the bottom and top of the battery cell after it is sunk. After the glue box is sealed on the top of the battery cell, it can generate glue to seal the side wall of the battery cell after curing.

[0019] Preferably, the base has a conical structure, and the protective seat has a storage slot for each battery cell. Horizontal spring guide rods are provided on both sides of the storage slots, and slide blocks are slidably installed on the spring guide rods. The support seat is installed through the slide blocks. The support seat adopts an inclined block structure, and the base is supported by two support seats.

[0020] Preferably, the elastic force of the spring guide rod allows the slide and the support to move to both sides, and a vertical pin is movably installed on the slide. A limit seat is provided at the bottom of the storage slot, and the pin can be connected to the limit seat to keep the slide in the extended state. A float is provided at the bottom of the pin.

[0021] Preferably, a liquid reservoir containing a diluent or neutralizing agent is provided on the side wall of the storage tank, which can be crushed when the support moves to both sides.

[0022] Preferably, the base is a frame structure, and the battery base plate is provided with a guide groove at each base position, and the lifting seat is located in the guide groove, and the side of the guide groove is provided with a leakage hole.

[0023] Preferably, the sleeve is located below the battery cell, and the inner wall of the sleeve is provided with a slope. The sealing ring is connected to the base support. When the base block falls on the base support, it can pull down the sealing ring so that the sealing ring is in close contact with the outer wall of the battery cell.

[0024] Preferably, guide seats are fixedly installed on both sides below the top seat, and the glue box is movably installed through the guide seats. An elastic element is fixedly connected to the glue box, which allows the glue box to pop out on the guide seat. A sealing plate is installed at the bottom of the glue box.

[0025] Preferably, there are two glue boxes, one containing glue A and the other containing glue B. The two glues can be mixed and cured to seal the sidewalls of the battery cells.

[0026] Preferably, a dispensing head is installed on the side of the glue box, and an opening component is provided on the dispensing head. The opening component includes a weak point and a needle. When two glue boxes are close to each other, the opening components on them come into contact with each other, and the needle can pierce the weak point.

[0027] Preferably, the dispensing head is equipped with an inclined groove, and the bottom of the guide seat is provided with a mixing ring. The mixing ring is sleeved on the battery cell, and the mixing ring is provided with an upward-facing inlet tube and a downward-facing dispensing hole.

[0028] Preferably, the battery cell has an upper terminal and a lower terminal at both ends, and adopts a contact-type power connection method. The top base is equipped with an upper electrical connector, and the base is equipped with a lower electrical connector.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. The lithium-ion battery of the present invention has an active leakage protection mechanism. Through the lifting installation structure and buoyancy triggering device, the electrical connection of the battery cell is automatically disconnected when the electrolyte leaks, which effectively prevents short circuits and thermal runaway caused by leakage, improves the overall safety of the battery pack, and the battery cell after sinking is sealed at the bottom by the sleeve sealing ring. At the same time, the top box closes to form a sealing layer. Combined with A / B glue curing technology, the leakage points on the side wall are actively sealed to achieve all-round leakage isolation.

[0031] 2. By incorporating a neutralizing agent or diluent within the reservoir, which is automatically released when the support moves, the corrosiveness of the leaked electrolyte is neutralized, reducing harm to metal components and the environment.

[0032] 3. The frame structure of the present invention adopts a detachable base and top mount layout, which facilitates the inspection or replacement of individual battery cells, avoids overall scrapping due to local failure, and reduces the hazards caused by electrolyte leakage from battery cells.

[0033] 4. The low internal resistance electrolyte provided by the present invention significantly improves ionic conductivity and Li⁺ transport number by using a composite solvent system of fluorocarboxylic acid ester and asymmetric cyclic carbonate, combined with double lithium salt and functional additives; the electrolyte can reduce interfacial impedance and has flame retardant properties. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure of the battery pack of the present invention.

[0035] Figure 2 This is a schematic diagram of the battery pack arrangement structure of the present invention.

[0036] Figure 3 This is a schematic diagram of the installation of the battery cell structure of the present invention.

[0037] Figure 4 This is a schematic diagram of the battery cell structure of the present invention.

[0038] Figure 5 This is a first schematic diagram of the top support structure of the present invention.

[0039] Figure 6 This is a second schematic diagram of the top support structure of the present invention.

[0040] Figure 7 This is a schematic diagram of the adhesive box structure of the present invention.

[0041] Figure 8 This is a schematic diagram of the protective base structure of the present invention.

[0042] Figure 9 This is a schematic diagram of the storage tank structure of the present invention.

[0043] Figure 10This is a schematic diagram of the support structure of the present invention.

[0044] Figure 11 This is a schematic diagram of the sleeve structure of the present invention.

[0045] In the diagram: 1. Battery base plate; 2. Base; 3. Side frame; 4. Top seat; 5. Battery cell; 6. Upper terminal; 7. Lower terminal; 8. Upper connector; 9. Lower connector; 10. Lifting seat; 11. Base block; 12. Protective seat; 13. Storage tank; 14. Spring guide rod; 15. Slide seat; 16. Support seat; 17. Pin; 18. Limiting seat; 19. Float plate; 20. Liquid reservoir; 21. Guide groove; 22. Leakage hole; 23. Sleeve; 24. Slope; 25. Sealing ring; 26. Base support; 27. Guide seat; 28. Glue box; 29. ​​Elastic element; 30. Sealing plate; 31. Glue outlet head; 32. Opening assembly; 33. Inclined groove; 34. Mixing ring; 35. Inlet pipe; 36. Glue outlet hole. Detailed Implementation

[0046] The present invention will now be further described with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. It should be understood that the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0047] Please see Figures 1 to 11 The present invention provides a technical solution: a low internal resistance electrolyte, which belongs to lithium-ion battery electrolytes, and the electrolyte comprises the following components:

[0048] Solvent system: composed of fluorocarboxylic acid ester and asymmetric cyclic carbonate, wherein the fluorocarboxylic acid ester is ethyl 2,2-difluoroacetate (EDFA), and the asymmetric cyclic carbonate is a mixture of fluoroethylene carbonate (FEC) and vinylene carbonate (VEC) in a 3:1 mass ratio;

[0049] Lithium salt combination: comprising lithium bis(fluorosulfonyl)imide (LiFSI) and lithium difluorooxalate borate (LiDFOB), wherein the concentration of LiFSI is 1.2-1.8 mol / L and the concentration of LiDFOB is 0.3-0.7 mol / L;

[0050] Multifunctional additive: Contains trithioethylene carbonate (TTS), tetrabutylammonium hexafluorophosphate (TBAPF6) and 2,6-di-tert-butyl-p-cresol (BHT).

[0051] Nanodispersed phase: surface-hydroxylated boron nitride nanosheets (BNNS) with -OH coverage ≥15%.

[0052] In the solvent system, EDFA accounts for 30-40% of the total mass of the electrolyte, and FEC and VEC together account for 20-30%.

[0053] In the multifunctional additive, TTS accounts for 2-4% of the total mass of the electrolyte, TBAPF6 accounts for 1-3%, and BHT accounts for 0.5-1%.

[0054] BNNS has a particle size of 50-200nm, a thickness of ≤5nm, and a dispersion concentration of 0.3-0.6wt% in the electrolyte.

[0055] Preparation method of hydroxylated BNNS:

[0056] BN nanosheets (Aladdin reagent, purity >99%) were mixed with 30% hydrogen peroxide at a mass ratio of 1:10, refluxed at 80°C for 6 hours, centrifuged and washed until neutral, and then vacuum dried to obtain BNNS with -OH coverage ≥15% (as determined by XPS).

[0057] The preparation method of the above electrolyte includes the following steps:

[0058] S1. Mix EDFA, FEC and VEC under an argon atmosphere and stir for 30-60 minutes;

[0059] S2. Add LiFSI and LiDFOB sequentially, and heat at 40°C to dissolve;

[0060] S3. Add TTS, TBAPF6 and BHT, and sonicate for 20 min;

[0061] S4. After adding BNNS, ultrasonically disperse at 300W power for 30 minutes.

[0062] Example 1: Preparation of low internal resistance electrolyte

[0063] Formula composition:

[0064] Solvent system (75wt%):

[0065] Ethyl 2,2-difluoroacetate (EDFA): 35%

[0066] Fluoroethyl carbonate (FEC): 24%

[0067] Vinyl carbonate (VEC): 8%

[0068] Lithium salt (20wt%):

[0069] LiFSI: 1.5 mol / L (corresponding to 18% of the total electrolyte mass)

[0070] LiDFOB: 0.5 mol / L (corresponding to 2%)

[0071] Additives (4.5wt%):

[0072] Ethyl trithiocarbonate (TTS): 3%

[0073] Tetrabutylammonium hexafluorophosphate (TBAPF6): 1.2%

[0074] BHT: 0.3%

[0075] Nanoscale dispersed phase (0.5wt%):

[0076] Hydroxylated boron nitride nanosheets (BNNS, -OH coverage 18%, particle size ~100nm)

[0077] Preparation steps:

[0078] In an argon glove box (H2O < 1 ppm, O2 < 1 ppm), EDFA, FEC and VEC were mixed and magnetically stirred for 40 min.

[0079] LiFSI and LiDFOB were added in three batches, and the mixture was heated in a 40°C water bath until completely dissolved.

[0080] TTS, TBAPF6 and BHT were added in sequence and ultrasonically treated (40 kHz, 20 min).

[0081] Add BNNS, ultrasonically disperse for 30 minutes using a 300W probe, let stand for 12 hours, and then filter (0.22μm PTFE membrane).

[0082]

[0083] Table 1

[0084] The table above shows the performance test results of the electrolyte prepared in Example 1 and the control example, where the control example is a conventional electrolyte used in commonly available lithium-ion batteries that was randomly selected.

[0085] Example 2: Matching Battery Assembly

[0086] Electrode and battery configuration:

[0087] positive electrode:

[0088] Active material: Single crystal LiNi0.8Mn0.1Co0.1O2 (coated with 5nm Li2ZrO3)

[0089] Coating parameters: surface loading 18 mg / cm², compaction density 3.4 g / cm³

[0090] negative electrode:

[0091] Active material: 12% pre-lithiated SiOx@C (x=1.0)

[0092] Coating parameters: surface loading 8 mg / cm², compaction density 1.6 g / cm³

[0093] Membrane: PE-based ceramic composite membrane (pore size 0.1μm, porosity 45%)

[0094] Electrolyte: The electrolyte prepared in Example 1, with a dosage of 0.3 g / Ah.

[0095] Battery assembly:

[0096] The positive and negative electrode sheets were vacuum dried at 120℃ for 12 hours;

[0097] Stacking is completed in a drying room (dew point < -40℃);

[0098] After injecting electrolyte, age for 48 hours (25℃);

[0099] Formation process: constant current charging at 0.1C to 4.2V, then constant voltage charging until current ≤0.05C.

[0100] This electrolyte achieves a balance of low internal resistance, wide temperature range, long lifespan, and high safety through four-dimensional optimization of solvent, lithium salt, additives, and nanophase, making it particularly suitable for power batteries, fast charging devices, and extreme environment applications.

[0101] A lithium-ion battery using the aforementioned low internal resistance electrolyte includes a frame structure for mounting individual battery cells 5. The frame structure includes a battery base plate 1, on which bases 2 are arranged and mounted, and a top mount 4 is mounted on the battery base plate 1 via side frames 3. The battery base plate 1 is a flat structure, the bases 2 are a frame structure, the side frames 3 support the top mount 4, and the top mount 4 is composed of multiple arranged connecting frames. The bases 2 and the connecting frames correspond one-to-one. The individual battery cells 5 are mounted between the bases 2 and the connecting frames. Each end of the individual battery cell 5 is provided with an upper terminal 6 and a lower terminal 7, respectively, using a contact-type electrical connection to avoid wiring connections. At the same time, an upper connector 8 is provided on the top mount 4, and a lower connector 9 is provided on the base 2, for connecting the upper terminals 6 and lower terminals 7 of two individual battery cells 5, respectively, to complete the electrical connection of all individual battery cells 5.

[0102] In the lithium-ion battery of the present invention, the battery cell 5 adopts a lifting installation structure, which can automatically sink and disconnect in the event of electrolyte leakage. A lifting seat 10 is installed at the bottom of the battery cell 5, and a bottom block 11 is provided on the bottom surface of the lifting seat 10. The bottom block 11 has a conical structure. The battery base plate 1 is fixedly installed on a protective seat 12, which serves as a support structure. A storage tank 13 is provided for each battery cell 5. The storage tank 13 serves as an absorption structure for leaked electrolyte and also as a sinking space for the battery cell 5. Horizontal spring guide rods 14 are provided on both sides, and slide blocks 15 are slidably installed on the spring guide rods 14. Support seats 16 are installed through the slide blocks 15. The support seats 16 adopt a wedge-shaped structure. The two support seats 16 can support the bottom block 11 and lift up the battery cell 5, so that the upper terminal 6 and lower terminal 7 of the battery cell 5 are connected to the upper connector 8 and lower connector 9 respectively. When electrolyte leakage occurs, the support seats 16 can be withdrawn to both sides, the supporting effect on the bottom block 11 disappears, the battery cell 5 can fall, and its electrical connection is disconnected to avoid affecting the overall safety of the battery pack.

[0103] The elastic force of the spring guide rod 14 can act on the slide 15, causing the slide 15 to tend to move the support seat 16 to both sides. At the same time, a vertical pin 17 is movably installed on the slide 15, and a limit seat 18 is correspondingly provided at the bottom of the storage tank 13. The pin 17 can be connected to the limit seat 18, thereby keeping the slide 15 in the extended state. The spring of the spring guide rod 14 is stretched, and the support seat 16 can support the bottom block 11. A float plate 19 is provided at the bottom of the pin 17. When the electrolyte of a certain battery cell 5 leaks into the storage tank... When the battery is in tank 13, the buoyancy generated causes the float 19 to rise, thereby disengaging the pin 17 from the limit seat 18. The slide 15 then moves the support seat 16, allowing the battery cell 5 to fall. Furthermore, a liquid storage bladder 20 is provided on the side wall of the storage tank 13, which is filled with diluent or neutralizing agent. When the support seat 16 moves to both sides, it can rupture the liquid storage bladder 20, causing the agent to flow out and neutralize or dilute the electrolyte in the storage tank 13, reducing the environmental hazards caused by electrolyte leakage.

[0104] The float 19 is made of polypropylene foam board with a density lower than that of the electrolyte, with a density of 0.2 g / cm³. An inclined guide channel is set at the bottom of the storage tank so that the leaked electrolyte can be concentrated below the float 19. The pin 17 is also made of common lightweight materials, so that the float 19 can lift the pin 17 under the buoyancy of the electrolyte.

[0105] The base 2 of the present invention has a frame structure, which can prevent the electrolyte leaked from the battery cell 5 from flowing out to other locations. At the same time, the battery base plate 1 is provided with a guide groove 21 at each position of the base 2 for the passage of the battery cell 5, and the side of the guide groove 21 is provided with a leakage hole 22, which allows the electrolyte to be collected into the storage tank 13.

[0106] A sleeve 23 is provided in the storage tank 13 to temporarily seal the bottom of the battery cell 5. The sleeve 23 is located below the battery cell 5. When the support base 16 is removed to both sides, the bottom of the battery cell 5 and the lifting base 10 can fall into the sleeve 23. The inner wall of the sleeve 23 is provided with a slope 24, and a sealing ring 25 is provided in the sleeve 23. The sealing ring 25 is connected to the base support 26. Under normal circumstances, the sealing ring 25 falls on the upper part of the slope 24 and is in a loose state to avoid affecting the entry of the battery cell 5. When the base block 11 falls on the base support 26, it can pull down the sealing ring 25, so that the sealing ring 25 moves to the lower part of the slope 24 and makes close contact with the outer wall of the battery cell 5. In the event of leakage at the bottom of the battery cell 5, it can prevent further outflow of electrolyte and confine it in the sleeve 23.

[0107] Meanwhile, the top seat 4 is also equipped with a sealing structure for temporarily sealing the top and side walls of the battery cell 5. This sealing structure includes guide seats 27 installed on both sides below the top seat 4. A glue box 28 is movably installed through the guide seats 27. An elastic element 29 is fixedly connected to the glue box 28. The elastic element 29 allows the glue box 28 to pop out on the guide seats 27. A sealing plate 30 is provided at the bottom of the glue box 28. When the battery cell 5 is in use, the glue box 28 is stuck on both sides of the battery cell 5 and cannot be closed. When the electrolyte of the battery cell 5 leaks and sinks, the two glue boxes 28 can close on the top surface of the battery cell 5. The sealing plate 30 achieves a sealing effect to prevent further leakage of electrolyte. Furthermore, there are two glue boxes 28, which contain A glue and B glue respectively. The two glues can be mixed and cured within a certain time to seal the side walls of the battery cell 5. The curing time is usually controlled at about one minute.

[0108] Both glue boxes 28 have glue dispensing heads 31 installed on their sides as glue leakage points. Each glue dispensing head 31 is equipped with an opening assembly 32, which includes a weak point and a needle. When the two glue boxes 28 are close together, the opening assemblies 32 on them come into contact with each other, and the needle punctures the weak point. The glue dispensing head 31 is also equipped with a sloping groove 33, from which the glue can flow down. At the same time, a mixing ring 34 is provided at the bottom of the guide seat 27. The mixing ring 34 is fitted onto the battery cell 5 and has an upward-facing inlet pipe 35 and a downward-facing glue dispensing hole 36. When the two glue boxes 28 are close together, the glue flows from the sloping groove 33 into the inlet pipe 35 and then into the mixing ring 34. After converging in the mixing ring 34, the glue flows out from the glue dispensing hole 36, covering the surface of the battery cell 5 and sealing the damaged points on the side wall of the battery cell 5 to prevent further leakage of electrolyte.

[0109] To ensure the sealing effect of the adhesive during curing, Glue A is made of epoxy resin with a viscosity of 200 cP and contains a delayed curing agent, while Glue B is made of amine curing agent with a viscosity of 150 cP. The inclined groove 33 is set with a width of 2 mm and an inclination angle of 30°, and the mixing ring 34 has a volume of 0.5 mL, ensuring that the adhesive completes flow and curing within 60 ± 5 seconds.

[0110] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low internal resistance electrolyte, characterized in that: Includes the following components: Solvent system: composed of fluorocarboxylic acid ester and asymmetric cyclic carbonate, wherein the fluorocarboxylic acid ester is ethyl 2,2-difluoroacetate, and the asymmetric cyclic carbonate is a mixture of fluoroethylene carbonate and vinylene carbonate in a 3:1 mass ratio. Lithium salt combination: comprising lithium bis(fluorosulfonyl)imide and lithium difluorooxalate borate, wherein the concentration of lithium bis(fluorosulfonyl)imide is 1.2-1.8 mol / L and the concentration of lithium difluorooxalate borate is 0.3-0.7 mol / L; Multifunctional additive: Contains ethylene trithiocarbonate, tetrabutylammonium hexafluorophosphate and 2,6-di-tert-butyl-p-cresol; Nanodispersed phase: boron nitride nanosheets with surface hydroxylation treatment, having a -OH coverage of ≥15%; In the solvent system, ethyl 2,2-difluoroacetate accounts for 30-40% of the total mass of the electrolyte, and fluoroethylene carbonate and vinylene carbonate together account for 20-30%. In the aforementioned multifunctional additive, trithioethylene carbonate accounts for 2-4% of the total mass of the electrolyte, tetrabutylammonium hexafluorophosphate accounts for 1-3%, and 2,6-di-tert-butyl-p-cresol accounts for 0.5-1%. The boron nitride nanosheets have a particle size of 50-200 nm, a thickness of ≤5 nm, and a dispersion concentration of 0.3-0.6 wt% in the electrolyte.

2. A lithium-ion battery using the low internal resistance electrolyte as described in claim 1, characterized in that: The lithium-ion battery includes: The frame structure consists of a battery base plate, a base, side frames, and a top mount. The base is a frame structure and is arranged and installed on the battery base plate. Battery cells, which are arranged and installed between the base and the top; The protective base is fixed below the battery base plate. The protective base is equipped with a storage tank to collect leaked electrolyte and provide sinking space for the battery cells. The battery cell adopts a lifting installation structure, and the bottom of the battery cell is provided with a lifting seat with a base block. The storage tank is equipped with a support seat that is telescopically installed through a spring guide rod. The battery cell is supported by the support seat contacting the base block. The support seat is kept in the supported state by a floating pin. When the electrolyte leaks, the buoyancy generated can unlock the pin. The storage tank is equipped with a sleeve with a movable sealing ring, and the top seat is equipped with a pop-out glue box with a sealing plate. The sleeve and the glue box can be used to seal the bottom and top of the battery cell after it sinks. After the glue box is sealed on the top of the battery cell, it can generate glue to seal the side wall of the battery cell after curing. The base has a conical structure, and the protective seat has a storage slot for each battery cell. Horizontal spring guide rods are provided on both sides of the storage slots, and slide blocks are slidably installed on the spring guide rods. The support base is installed through the slide blocks. The support base has an inclined block structure, and the base is supported by two support bases. The elastic force of the spring guide rod allows the slide and support to move to both sides, and a vertical pin is movably installed on the slide. A limit seat is provided at the bottom of the storage slot, and the pin can be connected to the limit seat to keep the slide in the extended state. A float plate is provided at the bottom of the pin. The storage tank has a liquid storage bladder on its side wall, which is filled with diluent or neutralizing agent. When the support moves to both sides, the liquid storage bladder can be crushed. Guide seats are fixedly installed on both sides below the top seat. The glue box is movably installed through the guide seats, and an elastic element is fixedly connected to the glue box. The elastic element allows the glue box to pop out on the guide seat. A sealing plate is installed at the bottom of the glue box. The adhesive box has two parts, one containing adhesive A and the other containing adhesive B. The two adhesives can be mixed and cured to seal the sidewalls of the battery cells. The glue box is equipped with a glue dispensing head on its side. The glue dispensing head is provided with an opening assembly. The opening assembly includes a weak point and a needle. When two glue boxes are close to each other, the opening assemblies on them come into contact with each other, and the needle can pierce the weak point. The dispensing head is equipped with an inclined groove, and the bottom of the guide seat is provided with a mixing ring. The mixing ring is sleeved on the battery cell, and the mixing ring is provided with an upward-facing inlet tube and a downward-facing dispensing hole.

3. A lithium-ion battery according to claim 2, characterized in that: The base is a frame structure, and the battery base plate is provided with a guide groove at each base position. The lifting seat is located in the guide groove, and the side of the guide groove is provided with a drain hole.

4. A lithium-ion battery according to claim 2, characterized in that: The sleeve is located below the battery cell, and the inner wall of the sleeve is sloped. The sealing ring is connected to a base. When the base block falls on the base, it can pull down the sealing ring, so that the sealing ring is in close contact with the outer wall of the battery cell.

5. A lithium-ion battery according to claim 2, characterized in that: The battery cell has an upper terminal and a lower terminal at both ends, and is connected by contact. The top base is equipped with an upper connector, and the base is equipped with a lower connector.

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