Dormant electrochemical energy storage cells

Abstract

This invention belongs to the field of electrochemical energy storage technology and relates to a dormant electrochemical energy storage cell, comprising a positive electrode, a negative electrode, and a solvent, electrolyte, and separator located between the positive and negative electrodes. The electrochemical energy storage cell has been encapsulated, the negative electrode has not undergone initial lithium insertion and has not formed an SEI film, and the positive electrode has not undergone activation. The cell is in an inert state, lacks continuous discharge capability, and does not possess thermal runaway triggering energy. The dormant electrochemical energy storage cell of this invention does not require pre-formation processes during production and can be directly encapsulated. The cell exhibits no capacity loss during long-term storage, excellent voltage consistency, and, because it is not classified as a hazardous material, can be safely and conveniently transported and assembled, reducing the total life cycle cost. In application scenarios, it can be directly activated without generating gas, making it suitable for energy storage batteries, power batteries, and consumer electronics batteries.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage technology and relates to a dormant electrochemical energy storage cell. Background Technology

[0002] Existing electrochemical energy storage devices, such as lithium-ion batteries, must undergo a formation (i.e., pre-activation) process before leaving the factory. The first charge and discharge process forms a solid electrolyte interphase (SEI) film and imparts initial charge to the battery. After the gas generated in this process is released, the battery is sealed. However, the above formation process leaves existing lithium-ion batteries in a charged state when they leave the factory, which presents the following core problems: (1) Long-term storage leads to a decrease in battery capacity and a serious decrease in the consistency of individual cells, requiring re-screening before use, making them unsuitable for long-term storage; (2) Transportation safety risks, as activated electrochemical energy storage devices are charged and belong to Class 9 dangerous goods, posing a risk of fire and explosion during transportation; (3) Assembly costs and safety issues, as operators need to wear insulating protective equipment when assembling battery modules, battery packs, or systems.

[0003] Currently, there are no reported lithium-ion battery technologies that require no formation, are non-charged, can be stored for long periods, are more cost-effective, and are safer. Therefore, there is an urgent need to develop a new electrochemical energy storage device that can be stored for long periods with high safety, meeting the requirements of energy storage systems and power battery systems for long-term storage, safe transportation, and low-cost assembly. Summary of the Invention

[0004] The purpose of the exemplary embodiments of the present invention is to solve the storage problems of existing electrochemical energy storage devices (e.g., capacity loss in existing activated battery storage, unsafe transportation and storage, short inventory cycle, high assembly cost, etc.), and to provide a dormant electrochemical energy storage unit that achieves the goals of long-term storage of the unit without capacity loss, safe transportation and assembly, and reduced total life cycle cost.

[0005] This invention provides a dormant electrochemical energy storage cell, comprising a positive electrode, a negative electrode, and a solvent, an electrolyte, and a separator membrane located between the positive and negative electrodes; wherein the electrochemical energy storage cell has been encapsulated, the negative electrode has not undergone initial lithium insertion and has not formed an SEI film, and the positive electrode has not undergone an activation reaction; the cell is in an inert state, does not have continuous discharge capability, and does not have thermal runaway triggering energy.

[0006] In embodiments of the present invention, the short-circuit energy of the electrochemical energy storage cell is ≤0.03J, and the short-circuit current is ≤1%-3% of the nominal current. In the present invention, the electrochemical energy storage cell only performs instantaneous discharge of the double-layer capacitor, without continuous discharge energy.

[0007] In an embodiment of the present invention, the initial open-circuit voltage range of the electrochemical energy storage cell is 0.5V ± 0.49V. In this invention, the initial open-circuit voltage is essentially the potential difference between the positive and negative electrodes when they reach electrochemical equilibrium in the electrolyte environment.

[0008] In an embodiment of the present invention, the absolute degree of lithiation X of the negative electrode is less than 0.04.

[0009] In an embodiment of the present invention, the coordination energy between the solvent and lithium ions is lower than the coordination energy between anions and lithium ions in the electrolyte.

[0010] In embodiments of the present invention, the housing is selected from any one or more of aluminum-plastic film, metal shell, ceramic shell, or plastic shell.

[0011] In embodiments of the present invention, the electrolyte comprises at least one lithium salt of formula (I): (I) In equation (I), X and Y are each independently represented by C. m F 2m+1 In the formula, m≥0.

[0012] In embodiments of the present invention, the solvent is selected from one or more of sulfonamides, ethers, fluorinated alkanes, and fluorinated ethers.

[0013] In embodiments of the present invention, the sulfonamides include at least one sulfonamide compound of formula (II): , , ,

[0014] (II)

[0015] In equation (II), R 1 Each is independently selected from F, Cl, CF3, and C. n H 2n+1 and C n H 2n+1-x F x ; R 2 and R 3 Each is independently selected from CF3 and C. n H 2n+1 and C n H 2n+1-x F x Where n≥1, 1<x≤2n+1; R 4 Each was independently selected from C k H 2k-q Fq and (CH2) k-1 The ring-based structure of O, where k≥3, 0≤q≤2k.

[0016] In embodiments of the present invention, the sulfonamide is selected from at least one of N,N-dimethylaminosulfonyl fluoride, N,N-diethylaminosulfonyl fluoride, N,N-dimethyltrifluoromethylsulfonylamine, cyclopropylsulfonamide, and chloromethylsulfonyl diethylamine.

[0017] In embodiments of the present invention, the lithium salt is selected from at least one of LiFSI and LiTFSI.

[0018] In embodiments of the present invention, after activation, the dormant electrochemical energy storage cell is used in any one of energy storage batteries, power batteries, and consumer electronics batteries. In embodiments of the present invention, the consumer electronics batteries include mobile phone batteries, tablet batteries, and laptop batteries.

[0019] In an embodiment of the present invention, the positive electrode includes a positive electrode current collector and a positive electrode active material coated on the surface of the positive electrode current collector. The positive electrode active material is selected from one or more of lithium iron phosphate, ternary materials, lithium cobalt oxide, lithium manganese oxide, and nickel manganese spinel.

[0020] In an embodiment of the present invention, the negative electrode includes a negative electrode current collector and a negative electrode active material coated on the surface of the negative electrode current collector, wherein the negative electrode active material is selected from one or more of graphite, soft carbon, and silicon-based materials.

[0021] In embodiments of the present invention, the separator is selected from one or more of polypropylene film, polyethylene film, and composite separator. In the present invention, the separator is located between the positive and negative electrodes and is used to separate the positive and negative electrodes.

[0022] In an embodiment of the present invention, the dormant electrochemical energy storage unit is assembled to form a module and / or an energy storage system, and the dormant electrochemical energy storage unit is activated by a control unit to ensure activation upon first charging.

[0023] The single-cell battery of this invention exhibits no capacity loss during long-term storage: after prolonged storage, the capacity after the first charge activation remains consistent with the factory-issued capacity, solving the capacity loss problem of existing electrochemical energy storage devices and extending the inventory period. The single-cell battery of this invention is not classified as a hazardous material, avoiding the risk of fire and explosion during ocean and long-distance transportation, and reducing transportation insurance and protection costs. The single-cell battery of this invention is safe and convenient to assemble; operators do not need to wear insulating protective equipment during assembly. Finally, the single-cell battery of this invention reduces formation processes; transportation and assembly protection costs are lowered, making it particularly suitable for large-scale energy storage and overseas export projects. Furthermore, it has strong compatibility, applicable to various chemical systems such as lithium iron phosphate and ternary lithium, and can be widely used in energy storage systems, power batteries, backup power supplies, mobile communication power devices, and other scenarios. Detailed Implementation

[0024] 1. Dormant electrochemical energy storage cells

[0025] In this invention, the dormant electrochemical energy storage cell differs from conventional energy storage cells or batteries in the prior art. It refers to a cell that remains in an inactive state after being packaged / sealed. In application scenarios, activating this dormant electrochemical energy storage cell provides electrochemical energy storage cells, batteries, and battery modules.

[0026] The dormant electrochemical energy storage cell of this invention includes a positive electrode, a negative electrode, and a solvent, electrolyte, and separator membrane located between the positive and negative electrodes. The electrochemical energy storage cell is fully encapsulated. The negative electrode has not undergone initial lithium insertion and has not formed an SEI film, and the positive electrode has not undergone an activation reaction. The cell is in an inert state (lacking continuous discharge capability) and does not possess thermal runaway triggering energy. The initial open-circuit voltage range of the electrochemical energy storage cell is 0.5V ± 0.49V, which is essentially the potential difference between the positive and negative electrodes when they reach electrochemical equilibrium in the electrolyte environment. The negative electrode is in a state where the absolute degree of lithiation X < 0.04.

[0027] The short-circuit energy of the dormant electrochemical energy storage cell described in this invention is ≤0.03J, ≤0.025J, ≤0.02J, ≤0.015J or ≤0.01J, and the short-circuit current is ≤1%-3%, 1.5%-2.5% or 2% of the nominal current.

[0028] The initial open-circuit voltage of the dormant electrochemical energy storage cell described in this invention typically satisfies 0.5V ± 0.49V. In a preferred embodiment, the initial open-circuit voltage of the cell is 0.1V-0.8V, 0.2V-0.79V, 0.3V-0.7V, or 0.4V-0.6V; more preferably, the initial open-circuit voltage of the cell is 0.3V-0.5V.

[0029] In an embodiment of the present invention, the negative electrode is in a state where the absolute degree of lithiation X<0.04, X<0.03, X<0.02, X<0.01.

[0030] In embodiments of the present invention, the electrolyte comprises lithium ions and anions, and the solvent has a water content ≤10ppm. The solvent comprises an organic solvent whose coordination energy with lithium ions is lower than that with lithium ions, i.e., there are no side reactions. In embodiments of the present invention, the electrolyte may be provided without additional additives, or film-forming additives may be added as needed, such as 0.5wt% of LiPO2F2 as a film-forming additive.

[0031] In an embodiment of the present invention, the electrolyte comprises at least one lithium salt selected from formula (I):

[0032] (I)

[0033] Where X and Y are each independently represented by C. m F 2m+1 In the formula, m ≥ 0. In some embodiments, m ≥ 1, ≥ 2, ≥ 5, or ≥ 10. In some embodiments, m 100 50. 20 or 10. In some embodiments, the lithium salt comprises LiFSI and / or LiTFSI.

[0034] In embodiments of the present invention, the solvent is an organic solvent selected from one or more of sulfonamides, ethers, fluorinated alkanes, and fluorinated ethers.

[0035] In embodiments of the present invention, the sulfonamides include at least one sulfonamide of formula (II): , , ,

[0036] (II)

[0037] In the formula, R 1 Each is independently selected from F, Cl, CF3, and C. n H 2n+1 and C n H 2n+1-x F x ; R 2 and R 3 Each is independently selected from CF3 and C. n H 2n+1 and Cn H 2n+1-x F x Where n≥1, 1<x≤2n+1; R 4 Each was independently selected from C k H 2k-q F q and (CH2) k-1 The ring-based structure of O, where k≥3, 0≤q≤2k.

[0038] In some embodiments of the present invention, n ≥ 2, ≥ 3, ≥ 4, or ≥ 5. In some embodiments, k ≥ 4, ≥ 5, ≥ 6, ≥ 7, or ≥ 8.

[0039] In embodiments of the present invention, the sulfonamides are selected from sulfonamides represented by general formula (II), wherein R 1 It is F, R 2 and R 3 Each was independently selected from C n H 2n+1 and C n H 2n+1-x F x In a more preferred embodiment, the sulfonamide is N,N-dimethylaminosulfonyl fluoride, N,N-diethylaminosulfonyl fluoride, N,N-dimethyltrifluoromethylsulfonylamine, or cyclopropylsulfonamide (containing R...). 4 Cycloyl group) and / or chloromethylsulfonyl diethylamine (R 1 (Using Cl) to adjust its polarity and lithium salt solubility, while also taking into account ionic conductivity.

[0040] In an embodiment of the present invention, the positive electrode comprises at least one active material selected from lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium nickel cobalt aluminum oxide, lithium-rich manganese-based materials, lithium manganese oxide, and lithium manganese iron phosphate.

[0041] 2. Preparation of dormant electrochemical energy storage monomers

[0042] This invention first completes monomer preparation, then performs basic assembly (i.e., assembly of positive and negative electrode sheets, separator, and electrolyte), and directly encapsulates / seals the monomer without performing a formation process. In embodiments of this invention, the preparation method mainly includes the following preparation steps:

[0043] S1: Electrode preparation, including the preparation of a positive electrode, a negative electrode, and a separator. The positive electrode is prepared by coating a current collector with a positive active material, a conductive agent, and a binder; the negative electrode is prepared by coating a current collector with a negative active material, a conductive agent, and a binder; the separator is a porous polymer membrane with ion conductivity. Specifically, Positive electrode sheet: A positive electrode active material (e.g., 90-96 wt%), a conductive agent (e.g., 2-5 wt%), and a binder (e.g., 2-10 wt%) are dispersed in N-methylpyrrolidone (NMP) to form a positive electrode slurry, which is then coated onto the surface of an aluminum foil current collector (e.g., 12-16 μm), vacuum dried at 120°C for 12 hours, rolled to the target compaction density, and punched into a specified size (e.g., Φ19 mm round sheet). Negative electrode sheet: The negative electrode active material (e.g., 90-95wt%), conductive agent (e.g., 2-5wt%), and binder (e.g., 3-5wt%) are dispersed in deionized water to form a negative electrode slurry, which is then coated onto the surface of a copper foil current collector (e.g., 8-12μm), vacuum dried at 100°C for 12 hours, rolled to the target compaction density, and punched into a specified size (e.g., Φ20mm round sheet). Separating membrane: A polyolefin microporous membrane with the above core structural parameters is selected and punched into a specified size (such as a Φ21mm round piece).

[0044] S2: Monomer forming: The above-mentioned positive electrode sheet, negative electrode sheet and separator are assembled into a monomer body in the order of "positive electrode sheet - separator - negative electrode sheet - separator" through winding or stacking process, so that the positive and negative electrode sheets are physically isolated by the separator.

[0045] S3: In the electrolyte injection process, the molded monomer body is placed in an aluminum-plastic film or metal shell for encapsulation, and then an electrolyte is injected into the monomer under an Ar atmosphere. The electrolyte contains at least a portion of liquid electrolyte (e.g., a liquid electrolyte containing LIFSI salt and N,N-dimethylaminosulfonyl fluoride solvent), with an injection volume of 5-8 g / Ah. After injection, the mixture is allowed to stand for 30 minutes to allow the electrolyte to fully wet the electrode and the separator, ensuring the initial establishment of the ion transport channel.

[0046] S4-S5: Skipping formation / pre-activation (this is the core difference between this invention and existing technologies), meaning that after liquid injection, traditional formation or pre-activation treatment is not performed; the monomer is directly sealed (soft-pack monomer heat-sealing, metal shell laser welding) to ensure isolation between the monomer's interior and the outside environment. The monomer is set to a dormant state where the SEI film is not activated, with an initial open-circuit voltage ≤0.5V±0.49V, preventing activation reaction at the negative electrode and the formation of a solid electrolyte interface (SEI) film on the negative electrode surface. In other words, the first charge-discharge cycle is skipped, directly obtaining a dormant electrochemical energy storage monomer.

[0047] The dormant electrochemical energy storage cell described in this invention meets one or more of the following conditions after being sealed: 1. No initial lithium insertion occurred at the negative electrode. (1) Open circuit voltage: 0.01V-0.99V, which is in the state of not being activated by charging and discharging, and the positive and negative electrode materials have not undergone redox reaction; In this invention, the initial open circuit voltage of the monomer is in the range of 0.5V±0.49V, and there is no negative electrode potential shift caused by lithium intercalation, which proves that the first lithium intercalation has not occurred.

[0048] (2) The absolute degree of lithiumization of the negative electrode X < 0.04, that is, the elemental analysis test is performed to determine the ratio of the actual lithium content of the negative electrode to the theoretical maximum lithium intercalation. The value is < 0.04, thus it is determined that the first lithium intercalation has not occurred.

[0049] 2. No SEI film formed.

[0050] (1) The initial open-circuit voltage was 0.5V±0.49V, which proves that there was no change in interface potential caused by the formation of SEI film.

[0051] (2) Solvent-lithium ion coordination energy < anion-lithium ion coordination energy, that is, the coordination energy between the solvent and lithium ion is lower than the coordination energy between the electrolyte anion and lithium ion, which is the thermodynamic condition for film formation without side reactions.

[0052] (4) No formation / pre-activation process: The preparation process skips the formation and pre-activation process and does not have the process conditions for the first charge-discharge film formation. The absence of SEI film can be quantitatively characterized from the process perspective.

[0053] (5) Microscopic observation: No SEI film was formed on the negative electrode, and the SEI film was formed by charging and activation when the monomer was used for the first time.

[0054] 3. No activation reaction occurred at the positive electrode.

[0055] (1) Initial open circuit voltage 0.5V±0.49V: The positive electrode will undergo delithiation oxidation reaction and the potential will increase significantly during activation. The initial voltage 0.5V±0.49V does not show an increasing trend, and quantitative characterization shows that the positive electrode has not undergone activation reaction.

[0056] (2) No redox reaction during the first charge and discharge: There is no redox capacity of positive electrode delithiation before the first charge, and no electrochemical reaction signal corresponding to the activation reaction.

[0057] (3) Short-circuit double-layer capacitance effect: When the positive and negative poles are short-circuited, the weak charge generated is entirely due to the double-layer capacitance effect of the positive and negative poles.

[0058] 4. The monomer is in an inert state (it does not have the ability to continuously discharge).

[0059] (1) Initial open circuit voltage 0.5V±0.49V (≤0.99V): The discharge platform without charged battery does not have a basis for continuous discharge voltage.

[0060] (2) Short-circuit energy ≤ 0.03J: It is only the instantaneous discharge of the double-layer capacitor, and there is no continuous discharge energy.

[0061] (3) Short circuit current ≤ 1%-3% of nominal current: The short circuit current is much lower than the nominal current, ≤ 1%-3% of the nominal current, and there is no continuous discharge current output.

[0062] (4) No available discharge capacity: Before the first activation of charging, there is no effective discharge capacity and it is unable to continuously supply power to the outside.

[0063] 5. Lacks thermal runaway triggering energy

[0064] (1) Temperature rise during short circuit ≤5℃: The maximum temperature during hard short circuit is ≤35℃, with no heat accumulation, and does not meet the thermal runaway temperature triggering condition; (2) The short-circuit current is ≤ 1% of the nominal current, and there is no energy basis for large current heating. (3) The initial open-circuit voltage is 0.5V±0.49V, that is, the individual cells are not charged and there is no thermal runaway energy storage basis; (4) Electrolyte does not produce gas and has a water content of ≤10ppm: When using sulfonamide-based non-gas-producing solvents, the water content of the electrolyte is ≤10ppm, and there are no factors that cause thermal runaway such as gas production or heat generation from side reactions.

[0065] In one embodiment of the present invention, the lithium-ion-containing monomer may include an outer packaging that can be used to encapsulate the aforementioned electrode assembly and electrolyte. In some embodiments, the outer packaging of the lithium-ion-containing monomer may be a rigid shell, such as a hard plastic shell, an aluminum shell, or a steel shell. In other embodiments, the outer packaging of the lithium-ion-containing monomer may be a flexible package, such as a pouch. The material of the flexible package may be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0066] The lithium-ion-containing monomer of this invention can be cylindrical, square, or any other arbitrary shape. The outer packaging may include a shell and a cover plate. The shell may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The shell has an opening communicating with the receiving cavity, and the cover plate can be placed over the opening to close the receiving cavity. A positive electrode, a negative electrode, and a separator can be formed into an electrode assembly using a winding or stacking process. This electrode assembly is encapsulated in the receiving cavity, and the electrolyte is immersed in the electrode assembly. The lithium-ion-containing monomer may contain one or more electrode assemblies.

[0067] Example

[0068] Table 1: Core structural parameters of the dormant electrochemical energy storage cell of this invention

[0069] The electrolyte preparation in this embodiment of the invention can refer to conventional methods in the field of lithium-ion battery manufacturing, and the main parameters are as follows: Raw material requirements: solvent water content ≤5ppm, lithium salt (LiFSI, etc.) water content ≤3ppm, and the entire process is carried out under an Ar atmosphere (oxygen content ≤10ppm, water content ≤10ppm); Preparation process: Add lithium salt to an organic solvent such as sulfonamide at a concentration of 1.0-1.2 mol / L, stir magnetically at 25°C for 2 hours (stirring rate 800 r / min), and then let stand to remove bubbles for 12 hours to obtain a clear and transparent electrolyte. The final electrolyte has an overall water content of ≤10 ppm. Additives are optional: 0.5wt% LiPO2F2, 0.3wt% VC and other film-forming additives can be added as needed. Stable film formation can still be achieved without additives.

[0070] Example 1

[0071] The lithium-ion dormant electrochemical energy storage cell, as described above, is assembled using an aluminum shell, employing a lithium iron phosphate cathode, a graphite anode, a polyethylene separator, and a non-gas-producing electrolyte, with a designed capacity of 5 Ah. In this embodiment, the formation process is omitted: conventional constant current and constant voltage formation is not performed (to avoid the formation of an SEI film and initial charge). The electrolyte is LiFSI (concentration 1.2 mol / L), and the solvent is N,N-dimethylaminosulfonyl fluoride. The water content is ≤8 ppm, and no additives are used.

[0072] Preparation process: Prepare according to the above S1-S5 steps, skip the formation process, directly seal, and dormant electrochemical energy storage monomers without any formation / pre-activation treatment after liquid injection, thus eliminating the formation process and avoiding a series of problems caused by charging after activation. The initial open-circuit voltage of a single unit is 0.4V. When the positive and negative terminals are short-circuited, the energy released during the short circuit is approximately 0.027 Joules, which is equivalent to a 1W LED working for 0.027 seconds.

[0073] Example 2

[0074] The only difference from Example 1 is that the monomer is a dormant electrochemical energy storage monomer in N,N-dimethyltrifluoromethanesulfonylamine organic solvent; the electrolyte is LiFSI (1.2 mol / L); the solvent is N,N-dimethyltrifluoromethanesulfonylamine with a water content ≤7 ppm; and no additives are used. The initial open-circuit voltage of the monomer is 0.39 V, and the energy released during short-circuiting when the positive and negative electrodes are shorted is approximately 0.025 Joules. No SEI film is formed on the negative electrode.

[0075] Example 3

[0076] The only difference from Example 1 is that the dormant electrochemical energy storage monomer contains a cyclopropyl sulfonamide organic solvent; the monomer system is the same as in Example 1 (lithium iron phosphate 5Ah monomer). The electrolyte is LiFSI (1.2mol / L), the solvent is cyclopropyl sulfonamide (R4 in formula (II) is cyclopropyl C3H6, k=3, q=0), the water content is ≤8ppm, and there are no additives. The initial open-circuit voltage of the monomer is 0.41V, and the energy released during short circuit when the positive and negative electrodes are shorted is about 0.031 Joules. No SEI film is formed on the negative electrode.

[0077] Example 4

[0078] Preparation of dormant electrochemical energy storage monomers of ternary material (NCM811).

[0079] The only difference from Example 1 is the use of a high-nickel ternary material (NCM811) positive electrode and a graphite / silicon composite negative electrode; all other parameters remain unchanged. The electrolyte is LiFSI (concentration 1.2 mol / L), and the solvent is N,N-diethylaminosulfonyl fluoride. Key parameters: initial open-circuit voltage 0.45V (≤1.0V, uncharged); energy released during short-circuiting when the positive and negative electrodes are shorted is approximately 0.028 Joules; the remaining structure and preparation process are consistent with Example 1. This demonstrates the universality of the present invention for different chemical systems.

[0080] Example 5

[0081] The only difference from Example 1 is that dimethyl ethylene glycol (DME) is used as the organic solvent, the water content is ≤7ppm, and no additives are used. The initial open-circuit voltage of the monomer is 0.3V, and the energy released during short circuit when the positive and negative electrodes are shorted is approximately 0.031 Joules. No SEI film is formed on the negative electrode.

[0082] Example 6

[0083] The only difference from Example 1 is that perfluorohexane is used as the organic solvent, the water content is ≤7ppm, and no additives are used. The initial open-circuit voltage of the monomer is 0.35V, and the energy released during short circuit when the positive and negative electrodes are shorted is approximately 0.032 Joules. No SEI film is formed on the negative electrode.

[0084] Example 7

[0085] The only difference from Example 1 is that fluoromethyl tert-butyl ether is used as the organic solvent, the water content is ≤7ppm, and no additives are used. The initial open-circuit voltage of the monomer is 0.31V, the energy released during short circuit when the positive and negative electrodes are shorted is about 0.031 Joules, and no SEI film is formed on the negative electrode.

[0086] Example 8

[0087] The only difference from Example 1 is that LiTFSI lithium salt (1.2 mol / L) was used instead of LiFSI in Example 1, and the solvent was N,N-dimethylaminosulfonyl fluoride. The initial open-circuit voltage of the monomer was 0.45 V, and the energy released during short circuit when the positive and negative electrodes were shorted was approximately 0.029 Joules. No SEI film was formed on the negative electrode.

[0088] Example 9

[0089] Based on Example 1, 0.5 wt% LiPO2F2 and 0.3 wt% vinylene carbonate (VC) were added. The initial open-circuit voltage of the monomer was 0.32 V, and the energy released during short circuit when the positive and negative electrodes were shorted was approximately 0.031 Joules. No SEI film was formed on the negative electrode.

[0090] Example 10

[0091] Based on Example 1, a ceramic shell was used for encapsulation, and a polyolefin composite film was used. The initial open-circuit voltage of the monomer was 0.45V, and the energy released during short circuit when the positive and negative electrodes were shorted was approximately 0.033 Joules. No SEI film was formed on the negative electrode.

[0092] Comparative Example 1

[0093] The difference from Example 1 (lithium-ion 5Ah monomer) is that the electrolyte is a conventional carbonate electrolyte (EC:DMC:EMC=1:1:1, LiPF6 concentration 1.2mol / L), with a water content ≤20ppm; after injection, conventional formation treatment is performed (0.05C charging to 3.6V, standing for 1 hour, 0.1C discharging to 2.5V) to obtain the formed monomer; core parameters: open circuit voltage 3.3V (charged, belonging to Class 9 dangerous goods), and an SEI film has been formed on the negative electrode.

[0094] Comparative Example 2 (Improved carbonate electrolyzed into monomers with VC additive)

[0095] The difference from Example 1 is as follows: the electrolyte is EC:DMC:EMC=1:1:1+LiPF6 (1.0mol / L)+1wt% VC film-forming additive, and the water content is ≤20ppm; the monomer system is the same as in Example 1 (lithium iron phosphate 5Ah monomer); the preparation process is also the same as in Comparative Example 1; the open circuit voltage is 3.3V (charged), and an SEI film is formed on the negative electrode.

[0096] Comparative Example 3

[0097] The difference from Example 1 is that LiPF6 is used as the lithium salt.

[0098] Because lithium hexafluorophosphate has low solubility in N,N-dimethylaminosulfonyl fluoride (theoretically about 0.4–0.5 mol / L), LiPF6 is ineffective when used alone as a lithium salt, and may even be unusable as a lithium salt on its own.

[0099] Comparative Example 4

[0100] The difference from Comparative Example 1 is that no conventional formation treatment is performed after liquid injection. Activation in the application scenario generates gas, causing the shell to bulge.

[0101] Performance testing

[0102] In all performance tests, each sample size was 10 monomers, and the test data were averages. Unless otherwise specified, the test environment was 25±2℃ and normal pressure. The core performance test equipment, methods and conditions were disclosed to ensure that the experiments were repeatable and the data were verifiable.

[0103] 1. Testing Method

[0104] (1) Open circuit voltage test

[0105] Test equipment: Blue Battery Test System (CT2001A), High-precision Digital Multimeter (Fluke 87V); Test conditions: 25±2℃, normal pressure, test after the unit / module has been standing for 2 hours; Test points: individual electrode tabs, and the positive and negative terminals of the module; Test method: Direct measurement with a multimeter, with Blue Electric system for auxiliary recording, accuracy ±0.001V.

[0106] (2) Short-circuit current test

[0107] Test equipment: DC short circuit tester (RK2681N), current sensor (Hall sensor CS3000); Test conditions: 25±2℃, normal pressure, test after standing for 2 hours for individual units / modules, short circuit duration 5s (to avoid heat accumulation); Test points: Direct short-circuit at the individual electrode tab (using copper busbar connection, contact resistance ≤0.01Ω), short-circuit the positive and negative terminals of the module; Test method: The positive and negative poles are hard short-circuited using a short-circuit tester, and the maximum current value during the short circuit is recorded with an accuracy of ±0.01A.

[0108] (3) Capacity retention test

[0109] Test equipment: Blue Battery Test System (CT2001A), Constant Temperature and Humidity Chamber (SHP150). Test conditions: 25±2℃ / 45±2℃, ambient pressure, charge / discharge regime is 1C constant current charge / discharge (lithium iron phosphate: 3.2V / 2.0V, ternary lithium: 4.2V / 2.5V). Test method: Test the initial capacity C0 of the single cell, and test the capacity C1 after storage / cycle. Capacity retention rate = (C1 / C0) × 100%, with an accuracy of ±0.1%.

[0110] (4) Voltage consistency test

[0111] Test equipment: Multi-channel voltage acquisition instrument (Xinwei BTS-8000); Test conditions: 25±2℃, normal pressure, test after the unit / module has been standing for 2 hours; Test method: Simultaneously collect the open-circuit voltage of all individual cells, calculate the voltage range (maximum value - minimum value), with an accuracy of ±0.001V.

[0112] (5) Test of absolute lithiation

[0113] Test equipment: Inductively coupled plasma optical emission spectrometer (ICP-OES), wavelength coverage of Li 670.784 nm (characteristic spectral line of lithium); Test conditions: Appendix H of GB / T 24533-2019 "Graphite Anode Materials for Lithium-ion Batteries" (Determination of Trace Metal Elements, Including Li); Calculation method: Absolute degree of lithiation X = Actual lithium content / Theoretical maximum lithium intercalation capacity (theoretically, graphite is about 372 mAh / g, corresponding to a Li mass fraction of about 8.4 wt%).

[0114] Table 2: Absolute lithiation data for Examples 1-10 and Comparative Examples 1-4.

[0115]

[0116] Test Example 1: Long-Term Storage Performance Test

[0117] 1.1 Test Method

[0118] The dormant electrochemical energy storage cells prepared in Examples 1-10 and the cells / batteries prepared in Comparative Examples 1-4 were statically stored in a constant temperature and humidity environment of 25°C and 50%RH for 6 / 12 / 24 months. The capacity retention rate, voltage consistency range, and screening pass rate (voltage deviation ≤0.05V is considered qualified) were tested according to the above test methods. It was observed whether the cells produced gas / bulged. Ten cells were tested in each group, and the average value of the data was taken (Examples 1-10 need to be activated by first controlled charging (i.e., activated in the application scenario), while Comparative Example 1 was tested directly).

[0119] Table 3: Long-term storage performance test data of Examples 1-10 and Comparative Examples 1-4

[0120] 1.3 Experimental Analysis

[0121] Experimental data shows that after 24 months of storage, the dormant electrochemical energy storage monomers of Examples 1-10 (the present invention) still maintained a capacity retention rate of over 98%, with a voltage consistency difference of only 0.02V-0.03V, a 100% screening pass rate, and no gas generation or bulging. This effectively solves the technical problems of poor post-formation storage performance, short storage cycles, and severe consistency degradation. In contrast, the capacity retention rate of Comparative Examples 1-4 (traditional formed monomers) dropped below 96% after 3 months of storage, consistency significantly decreased after 6 months, the screening pass rate was only 60% after 12 months, and the capacity loss was nearly 10% after 24 months, with obvious bulging. This demonstrates that the dormant electrochemical energy storage monomers of the present invention do not require pre-activation and do not form an SEI film, avoiding capacity loss caused by continuous SEI film consumption. Furthermore, the use of a sulfonamide-based non-gas-generating electrolyte eliminates electrolyte decomposition and gas generation during storage, ensuring monomer consistency, significantly extending the storage cycle, and reducing inventory loss costs.

[0122] Test Example 2: Transportation Safety Test

[0123] 2.1 Test Method

[0124] The individual units or modules from Examples 1-10 were placed in a vehicle transportation environment for testing. Ten units were tested in each group, and the average data was taken. Specific extreme test conditions were as follows: Collision test: 50g collision acceleration, 10ms collision duration, 3 collisions in each direction (front, back, left, and right); High temperature exposure: 60℃ constant temperature, 50%RH, exposure for 48 hours; Transportation duration: Simulated road and ocean transport, total duration 72 hours; Test the short-circuit current and maximum short-circuit temperature using the above test methods, observe the appearance integrity of the unit after transportation, and check for fire / explosion / leakage to verify the energized state and hazardous material classification.

[0125] 2.2 Experimental Results and Analysis

[0126] Experimental tests show that the dormant electrochemical energy storage cell of Example 1 of this invention is uncharged in the vehicle transportation environment, with a short-circuit current of less than 0.3A, and exhibits no abnormalities after transportation. Similarly, the cells of Examples 2-10 are all uncharged in the vehicle transportation environment, exhibit no abnormalities after transportation, and do not belong to Class 9 dangerous goods, thus avoiding the dangerous goods classification risks associated with the transportation of traditional electrochemical energy storage devices; there were no fires, explosions, or leaks during transportation, demonstrating excellent safety. The dormant electrochemical energy storage cell of this invention avoids the generation of large amounts of heat and electrolyte decomposition caused by abnormal short circuits in the transportation environment, fundamentally solving the safety hazards of transportation and storage.

[0127] 3. Effects and Advantages

[0128] By comparing the above Examples 1-10 with Comparative Examples 1-4, it can be fully verified that the technical solution of the present invention solves the core pain point caused by the formation process of existing electrochemical energy storage devices, fills the gap in the prior art, and has the following significant effects and advantages: Excellent long-term storage performance: After 24 months of storage, the capacity retention rate of the dormant electrochemical energy storage unit is ≥98.0%, the voltage consistency difference is ≤0.03V, the screening pass rate is 100%, there is no gas production / bulging, and the inventory cycle is extended from ≤3 months to more than 24 months, which greatly reduces inventory scrapping losses.

[0129] High safety during transportation and storage: individual units are ≤1V, non-electric, not classified as Class 9 dangerous goods, short-circuit current is ≤1% of nominal current, maximum short-circuit temperature is ≤35℃, and there is no fire / explosion / leakage after being subjected to a 50g impact and 60℃ exposure, completely avoiding the safety hazards of traditional electrochemical energy storage devices.

[0130] Furthermore, since the individual units described in this invention are not charged, the number of operators required is reduced, and there is no need for insulation protection and pre-charge equalization, allowing for the assembly of modules and systems.

[0131] In summary, this invention is the first to achieve the requirements of long-term storage, safe transportation, and low-cost assembly for electrochemical energy storage cells that are non-formation-required, can be stored for a long time, and are safe and efficient. The technical solution is reasonable and feasible, and has significant practicality, innovation, and industrial application value.

[0132] Although the invention has been described in conjunction with specific embodiments, those skilled in the art will understand that many modifications and variations can be made to the invention. Therefore, it is to be appreciated that the claims are intended to cover all such modifications and variations that fall within the true concept and scope of the invention.

Claims

1. A dormant electrochemical energy storage cell, comprising a positive electrode, a negative electrode, and a solvent, an electrolyte, and a separating membrane located between the positive and negative electrodes; wherein, The electrochemical energy storage cell has been encapsulated, the negative electrode has not undergone initial lithium insertion and has not formed an SEI film, and the positive electrode has not undergone an activation reaction; the cell is in an inert state, does not have continuous discharge capability, and does not have thermal runaway triggering energy.

2. The dormant electrochemical energy storage cell according to claim 1, characterized in that, The short-circuit energy of the electrochemical energy storage cell is ≤0.03J, and the short-circuit current is ≤1%-3% of the nominal current.

3. The dormant electrochemical energy storage cell according to claim 1, characterized in that, The initial open-circuit voltage range of the electrochemical energy storage cell is 0.5V ± 0.49V.

4. The dormant electrochemical energy storage cell according to claim 1, characterized in that, The absolute degree of lithiation of the negative electrode X < 0.

04.

5. The dormant electrochemical energy storage cell according to claim 4, characterized in that, The coordination energy between the solvent and lithium ions is lower than the coordination energy between anions and lithium ions in the electrolyte.

6. The dormant electrochemical energy storage cell according to claim 1, characterized in that, The housing is selected from any one or more of aluminum-plastic film, metal shell, ceramic shell or plastic shell.

7. The dormant electrochemical energy storage cell according to claim 1, characterized in that, The electrolyte comprises at least one lithium salt of formula (I): (I) In equation (I), X and Y are each independently represented by C. m F 2m+1 In the formula, m≥0.

8. The dormant electrochemical energy storage cell according to claim 1, characterized in that, The solvent is selected from one or more of sulfonamides, ethers, fluorinated alkanes, and fluorinated ethers.

9. The dormant electrochemical energy storage cell according to claim 8, characterized in that, The sulfonamides include at least one sulfonamide compound of formula (II): 、 、 、 (II) In equation (II), R 1 Each is independently selected from F, Cl, CF3, and C. n H 2n+1 and C n H 2n+1-x F x ; R 2 and R 3 Each is independently selected from CF3 and C. n H 2n+1 and C n H 2n+1-x F x Where n≥1, 1<x≤2n+1; R 4 Each was independently selected from C k H 2k-q F q and (CH2) k-1 The ring-based structure of O, where k≥3, 0≤q≤2k.

10. The dormant electrochemical energy storage cell according to claim 8, characterized in that, The sulfonamides are selected from at least one of N,N-dimethylaminosulfonyl fluoride, N,N-diethylaminosulfonyl fluoride, N,N-dimethyltrifluoromethylsulfonylamine, cyclopropylsulfonamide, and chloromethylsulfonyl diethylamine.

11. The dormant electrochemical energy storage cell according to claim 7, characterized in that, The lithium salt is selected from at least one of LiFSI and LiTFSI.

12. The dormant electrochemical energy storage cell according to claim 1, characterized in that, After activation, the dormant electrochemical energy storage cell can be used in any one of energy storage batteries, power batteries, and consumer electronics batteries.

13. The dormant electrochemical energy storage cell according to claim 1, characterized in that, The positive electrode includes a positive electrode current collector and a positive electrode active material coated on the surface of the positive electrode current collector. The positive electrode active material is selected from one or more of lithium iron phosphate, ternary materials, lithium cobalt oxide, lithium manganese oxide, and nickel manganese spinel.

14. The dormant electrochemical energy storage cell according to claim 1, characterized in that, The negative electrode includes a negative electrode current collector and a negative electrode active material coated on the surface of the negative electrode current collector. The negative electrode active material is selected from one or more of graphite, soft carbon, and silicon-based materials.

15. The dormant electrochemical energy storage cell according to claim 1, characterized in that, The separator is selected from one or more of polypropylene film, polyethylene film, and composite separator.

16. The dormant electrochemical energy storage cell according to claim 1, characterized in that, The dormant electrochemical energy storage cells are assembled into modules and / or energy storage systems, and the dormant electrochemical energy storage cells are activated by a control unit to ensure activation upon first charging.

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