Safe core battery based on system safety and preparation method thereof

Abstract

The invention belongs to the technical field of lithium ion battery safety, and discloses a safety cell battery based on system safety and a preparation method thereof.The safety cell battery based on system safety comprises a battery shell, a battery cell and a built-in static repair management system, the interior of the battery shell is divided into a battery cell bin and an equipment bin, the battery cell is installed in the battery cell bin, and the equipment bin is connected with the equipment bin; the built-in static repair management system is mounted in the equipment bin; the battery cell comprises a first coupling free energy balance film, a second coupling free energy balance film, a naked battery cell, an electrolyte, a positive pole lug and a negative pole lug; the composite lithium battery paper is obtained by sequentially laminating and combining the negative plate, the first isolating membrane and the positive plate into a whole. The method is suitable for new energy automobiles and various chemical energy storage batteries, the process is simple, materials are common, the cost is low, the cooperation function of a safety system is fully played, and the battery safety in the future is improved to the higher level in the industry using the battery.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium ion battery safety, and relates to a safe battery based on system safety and a preparation method thereof. BACKGROUND

[0002] In recent years, with the construction practice of new energy vehicles and large-scale energy storage demonstration projects, lithium ion batteries are widely used in the automobile field, and at the same time, the demand for improving the safety of the batteries is also brought.

[0003] A lithium ion battery is an energy aggregate, and 1kwh of storage capacity is equivalent to the energy of 0.86kg of TNT high explosive. If 1kwh of storage capacity is released at a high speed, the only path is combustion and explosion. In theory, the free energy of the electrochemical reaction in the charging process of a lithium ion battery is positive, that is, the electrochemical reaction naturally terminates when the charging power supply is cut off, and no combustion and explosion accident occurs. Only the free energy of the electrochemical reaction in the discharging process is negative, that is, the electrochemical reaction will spontaneously proceed until the reaction is completed even if the power supply is cut off when the discharging process is out of control. This is the reason why battery combustion and explosion accidents always occur inside.

[0004] At present, the safety measures for lithium ion batteries at home and abroad mainly include some safety valves, management systems, flame-retardant materials, sealed containers and the like. These measures are physical methods to solve chemical problems, and the internal structure of the lithium ion battery is not improved to prevent combustion and explosion. Therefore, a safe battery based on system safety is designed to control combustion and explosion from the source, which is more conducive to reducing safety risks. SUMMARY

[0005] The purpose of the present application is to provide a safe battery based on system safety to improve the safety of lithium ion batteries during use.

[0006] Another purpose of the present application is to provide a preparation method of a safe battery based on system safety.

[0007] In order to achieve the above purpose, the technical solution adopted by the present application is as follows:

[0008] A safe battery based on system safety, comprising a battery shell having a containing space inside and a battery core, the battery shell is divided into a battery core compartment and an equipment compartment, and the battery core is installed in the battery core compartment; further comprising a built-in static repair management system for static repair of the battery core after the battery core stops charging and discharging, preventing system misjudgment caused by overcharging and overdischarging, and having an electronic identity card function to perform data tracing; the built-in static repair management system is installed in the equipment compartment.

[0009] The electric core comprises a first coupling free energy balance film, a second coupling free energy balance film, a bare electric core, an electrolyte, a positive electrode tab and a negative electrode tab; the bare electric core comprises N composite lithium electric papers, N≥1, N being an integer; the composite lithium electric papers are sequentially stacked and combined into one body through a negative electrode sheet, a first isolation film and a positive electrode sheet to obtain the bare electric core;

[0010] When N=1, the bare electric core is formed by a single composite lithium electric paper; when N≥2, the bare electric core is formed by sequentially stacking each composite lithium electric paper and separating each composite lithium electric paper through a second isolation film, and the composite lithium electric papers are connected in series or in parallel; the bare electric core is arranged between the first coupling free energy balance film and the second coupling free energy balance film and is surface-bonded to the first coupling free energy balance film and the second coupling free energy balance film.

[0011] The positive electrode tab connects each positive electrode sheet of the bare electric core to a positive electrode terminal of the built-in static repair management system, and the negative electrode tab connects each negative electrode sheet of the bare electric core to a negative electrode terminal of the built-in static repair management system to form a safe bare electric core.

[0012] A first infusion tube for inputting the electrolyte and a second infusion tube for discharging and exhausting are mounted on the upper side wall of the electric core bin; a positive electrode terminal, a negative electrode terminal and a CAN communication low-voltage power supply terminal are mounted on the side wall of the equipment bin; the positive electrode terminal, the negative electrode terminal and the CAN connector of the built-in static repair management system are respectively connected to the positive electrode terminal, the negative electrode terminal and the CAN communication low-voltage power supply terminal in one-to-one correspondence.

[0013] As a limitation, the positive electrode sheet comprises a positive electrode current collector for formatting the battery energy unit and a positive electrode active film coated on the surface of the positive electrode current collector, and the negative electrode sheet comprises a negative electrode current collector for formatting the battery energy unit and a negative electrode active film coated on the surface of the negative electrode current collector.

[0014] The positive electrode tab connects the positive electrode current collector of each positive electrode sheet in the bare electric core to the positive electrode terminal of the built-in static repair management system, and the negative electrode tab connects the negative electrode current collector of each negative electrode sheet in the bare electric core to the negative electrode terminal of the built-in static repair management system.

[0015] As a further limitation, the material of the positive electrode current collector is graphene, graphite or carbon nanotube and is broken at 120℃-180℃ to cut off the positive electrode electron conduction;

[0016] The material of the negative electrode current collector is graphene, graphite or carbon nanotube and is broken at 120℃-180℃ to cut off the negative electrode electron conduction.

[0017] As a second limitation, the first coupling free energy balance film and the second coupling free energy balance film are of the same structure, each comprising an upper lithium ion shuttling outer sealing film, a lower lithium ion shuttling outer sealing film, and an intermediate high-elasticity fire and explosion stopping film sealed between the upper lithium ion shuttling outer sealing film and the lower lithium ion shuttling outer sealing film.

[0018] The upper lithium ion shuttling outer sealing film and the lower lithium ion shuttling outer sealing film are both anti-leakage insulation films; the intermediate high-elasticity fire and explosion stopping film is a three-dimensional porous high-elasticity film, and 0-60% of a flame retardant is adsorbed in the three-dimensional pores or on the outer surface of the three-dimensional porous high-elasticity film.

[0019] As a third limitation, the gap between the inner wall of the battery cell compartment and the battery cell is filled with a filling glue, and the liquid outlet of the first liquid delivery pipe and the liquid outlet of the second liquid delivery pipe are directly converted into a safety pressure relief valve through heat sealing.

[0020] As a further limitation, when the internal temperature of the battery shell reaches 120-180 DEG C, and the pressure reaches 0.5-1 MPa, the filling glue fails, and the battery shell opens to release the pressure.

[0021] The application also provides a preparation method of the safety battery based on system safety.

[0022] S1, sequentially stack the negative electrode sheet, the first isolation film and the positive electrode sheet to form an integrated body, and heat-composite under the condition of heating at 120-180 DEG C and pressurizing at 0.3-0.5 MPa to form a composite lithium battery paper;

[0023] S2, the N composite lithium battery papers are made into a bare battery cell; when N=1, the bare battery cell is a single composite lithium battery paper; when N is greater than or equal to 2, the composite lithium battery papers are sequentially stacked and separated by the second isolation film, then combined into an integrated body, and then connected in series or parallel to form a bare battery cell;

[0024] The bare battery cell is arranged between the first coupling free energy balance film and the second coupling free energy balance film, and is surface-bonded to the first coupling free energy balance film and the second coupling free energy balance film.

[0025] Each positive electrode sheet of the bare battery cell is connected to the positive terminal of the built-in static repair management system through the positive electrode tab, and each negative electrode sheet of the bare battery cell is connected to the negative terminal of the built-in static repair management system through the negative electrode tab, to form a safe bare battery cell.

[0026] S3, install the safety bare battery cell in the battery cell compartment of the battery shell, and set the first liquid inlet pipe and the second liquid inlet pipe; install the built-in static repair management system in the equipment compartment of the battery shell, and connect the positive terminal, the negative terminal and the CAN connector of the built-in static repair management system with the positive terminal, the negative terminal and the CAN communication low-voltage power terminal one by one respectively;

[0027] S4, fill and seal all the gaps between the inner wall of the battery cell compartment and the safety bare battery cell with filling glue, and then input the electrolyte through the first liquid inlet pipe and the second liquid inlet pipe to form the battery cell;

[0028] S5, charge and discharge the battery cell through the positive terminal, the negative terminal and the CAN communication low-voltage power terminal, and heat seal the liquid inlet of the first liquid inlet pipe and the liquid outlet of the second liquid inlet pipe to make the safety battery cell based on the system.

[0029] As a limitation, the positive sheet includes a positive current collector for formatting the battery energy unit and a positive active film coated on the surface of the positive current collector, and the negative sheet includes a negative current collector for formatting the battery energy unit and a negative active film coated on the surface of the negative current collector;

[0030] The specific process of step S2 is as follows:

[0031] N composite lithium electric papers are made into a bare battery cell; when N=1, the bare battery cell is a single composite lithium electric paper; when N≥2, the composite lithium electric papers are sequentially stacked and separated by the second isolation film, and then combined into one, and then the composite lithium electric papers are connected in series or parallel to form a bare battery cell;

[0032] The bare battery cell is arranged between the first coupling free energy balance film and the second coupling free energy balance film, and is surface-bonded with the first coupling free energy balance film and the second coupling free energy balance film;

[0033] The positive current collector of each positive sheet in the bare battery cell is connected with the positive terminal of the built-in static repair management system through the positive lug, and the negative current collector of each negative sheet in the bare battery cell is connected with the negative terminal of the built-in static repair management system through the negative lug.

[0034] As a further limitation, the material of the positive current collector is graphene, graphite or carbon nanotube, and the positive electronic conduction is cut off when the temperature is 120℃-180℃;

[0035] The material of the negative current collector is graphene, graphite or carbon nanotube, and the negative electronic conduction is cut off when the temperature is 120℃-180℃.

[0036] Compared with the prior art, the technical progress achieved by the application is that:

[0037] (1) The system safety-based safe core battery of the present invention includes a battery shell with an internal accommodating space, a battery cell and a built-in static repair management system. The interior of the battery shell is divided into a battery cell compartment and an equipment compartment. The battery cell is installed in the battery cell compartment, and the built-in static repair management system is installed in the equipment compartment. The battery cell includes a first coupled free energy balance membrane, a second coupled free energy balance membrane, a bare battery cell, an electrolyte, a positive electrode tab and a negative electrode tab; wherein, the built-in static repair management system is used to perform static repair after the battery cell stops charging and discharging, so as to slow down the attenuation of the reversible capacity of the battery cell, thereby extending the battery life and reducing safety risks, and preventing overcharge and over-discharge problems caused by system misjudgment. The built-in static repair management system also has an electronic ID card function, which is convenient for data tracing; the bare battery cell is arranged between the first coupled free energy balance membrane and the second coupled free energy balance membrane and is bonded to their surfaces. The first coupled free energy balance membrane and the second coupled free energy balance membrane balance the free energy inside the battery cell before the battery thermal runaway, terminate the spontaneous thermal runaway chemical reaction, improve the stability and impact resistance of the battery cell, reduce the risk of short circuit and explosion, and improve the stability and safety of the battery cell;

[0038] (2) The positive electrode sheet of the Anxin battery based on system safety of the present invention includes a positive electrode collector for formatting the battery energy unit and a positive electrode active film coated on the surface of the positive electrode collector, and the negative electrode sheet includes a negative electrode collector for formatting the battery energy unit and a negative electrode active film coated on the surface of the negative electrode collector; wherein, the materials of the positive electrode collector and the negative electrode collector are both graphene, graphite or carbon nanotubes, which have a conductive effect; in addition, since the carriers of the positive electrode collector and the negative electrode collector are non-metallic, the positive and negative electrodes can be used interchangeably; according to the materials of the positive electrode collector and the negative electrode collector, when the temperature in the battery reaches 120℃~180℃, the positive electrode collector or the negative electrode collector will melt and cut off the corresponding positive electrode or negative electrode electronic conductivity to prevent the lithium ion battery from exploding. Therefore, the positive electrode collector and the negative electrode collector of the present invention can format the battery with the minimum energy unit, i.e., the composite lithium battery paper, at the set temperature to prevent thermal runaway;

[0039] (3) The first coupling free energy balance membrane and the second coupling free energy balance membrane in the safe core battery based on system safety of the present invention have the same structure, both comprising an upper lithium ion shuttling prevention outer sealing membrane, a lower lithium ion shuttling prevention outer sealing membrane, and an intermediate high-elastic flame retardant and explosion-stopping membrane sealed between the upper lithium ion shuttling prevention outer sealing membrane and the lower lithium ion shuttling prevention outer sealing membrane; while not affecting the charge and discharge performance of the lithium ion battery, it can introduce a sufficient amount of cheap flame retardant to directly destroy the chain chemical reaction chain of battery combustion, with good flame retardant and explosion-stopping effects, eradicating the safety hazards of lithium ion batteries, and being suitable for large-scale promotion and application;

[0040] (4) The preparation method of the safety core battery based on the system safety of the application is easy to produce and manufacture, has low production cost, and is suitable for enterprise scale production.

[0041] In summary, the application is suitable for new energy vehicles and various chemical energy storage batteries, has simple process, universal materials and low cost, fully plays the cooperative function of the safety system, and improves the future battery safety to the high level of the safety core application industry. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 Fig. 1 shows the structure of the safety core battery based on the system safety in embodiment 1 of the application;

[0043] Figure 2 Fig. 2 shows the method flow chart of the preparation method of the safety core battery based on the system safety in embodiment 2 of the application;

[0044] In the figure: 1, battery shell; 2, battery core compartment; 3, equipment compartment; 4, built-in static repair management system; 5, first coupled free energy balance film; 6, second coupled free energy balance film; 7, positive electrode tab; 8, negative electrode tab; 9, composite lithium battery paper; 10, positive electrode current collector; 11, positive electrode active film; 12, first isolation film; 13, negative electrode current collector; 14, negative electrode active film; 15, second isolation film; 16, first infusion tube; 17, second infusion tube; 18, positive electrode terminal; 19, negative electrode terminal; 20, CAN communication low-voltage power supply terminal. DETAILED DESCRIPTION

[0045] In order to better explain the application and facilitate understanding, the application is described in detail in combination with the drawings and specific embodiments.

[0046] Embodiment 1: a safety core battery based on system safety

[0047] As shown in the figure, the embodiment is a safety core battery based on system safety, which comprises a battery shell 1 with an accommodating space inside and a battery core. Figure 1 The battery shell 1 is internally divided into a battery core compartment 2 and an equipment compartment 3, and the battery core is installed in the battery core compartment 2; it also comprises a built-in static repair management system 4 for preventing overcharging and overdischarging caused by the reversible capacity attenuation prevention system misjudgment of the static repair of the battery core after stopping charging and discharging, and having an electronic identity card function to perform data tracing; the built-in static repair management system 4 is installed in the equipment compartment 3.

[0048] In the embodiment, the battery core comprises a first coupled free energy balance film 5, a second coupled free energy balance film 6, a bare battery core, an electrolyte, a positive electrode tab 7 and a negative electrode tab 8; the bare battery core comprises N composite lithium battery papers 9, N≥1, N is an integer; the composite lithium battery paper 9 is obtained by sequentially laminating and combining a negative electrode tab, a first isolation film 12 and a positive electrode tab into one body.

[0049] The positive electrode sheet comprises a positive electrode current collector 10 for formatting the battery energy unit and a positive electrode active film 11 coated on the surface of the positive electrode current collector 10, and the negative electrode sheet comprises a negative electrode current collector 13 for formatting the battery energy unit and a negative electrode active film 14 coated on the surface of the negative electrode current collector 13; the material of the positive electrode current collector 10 adopts graphene, graphite or carbon nanotube and breaks at a temperature of 120-180℃ to cut off the positive electrode electron conduction; the material of the negative electrode current collector 13 also adopts graphene, graphite or carbon nanotube and breaks at a temperature of 120-180℃ to cut off the negative electrode electron conduction.

[0050] The materials of the positive electrode current collector 10 and the negative electrode current collector 13 have the effect of conducting electricity because they all adopt graphene, graphite or carbon nanotube; in addition, the positive electrode current collector 10 and the negative electrode current collector 13 can be universal because their carriers are non-metals such as graphene; according to the materials of the positive electrode current collector 10 and the negative electrode current collector 13, when the temperature in the battery reaches 120-180℃, the positive electrode current collector 10 and the negative electrode current collector 13 will be fused, preventing the lithium ion battery from exploding, so the positive electrode current collector 10 and the negative electrode current collector 13 of the embodiment can format the battery into the minimum energy unit, i.e. the composite lithium battery paper 9, at a set temperature, preventing thermal runaway, i.e. the positive electrode current collector 10 and the negative electrode current collector 13 can break and cut off the electron conduction function at 120-180℃, formatting the battery into the minimum energy unit composed of a single composite lithium battery paper 9.

[0051] In the embodiment, when N=1, a bare battery cell is formed by a single composite lithium battery paper 9; when N≥2, the bare battery cell is formed by stacking each composite lithium battery paper 9 in turn and separating each composite lithium battery paper 9 by the second isolation film 15, and then combining them into one, and the bare battery cell is formed by connecting each composite lithium battery paper 9 in series or parallel; the bare battery cell is arranged between the first coupling free energy balance film 5 and the second coupling free energy balance film 6, and is attached to the surface of the first coupling free energy balance film 5 and the second coupling free energy balance film 6. The positive electrode tab 7 connects the positive electrode current collector 10 of each positive electrode sheet in the bare battery cell to the positive electrode terminal of the built-in static repair management system 4, and the negative electrode tab 8 connects the negative electrode current collector 13 of each negative electrode sheet in the bare battery cell to the negative electrode terminal of the built-in static repair management system 4, forming a safe bare battery cell.

[0052] The first coupling free energy balance membrane 5 and the second coupling free energy balance membrane 6 have identical structures, each comprising an upper lithium ion shuttling-proof outer sealing membrane, a lower lithium ion shuttling-proof outer sealing membrane, and an intermediate elastomeric flame and explosion retardant membrane sealed between the upper and lower lithium ion shuttling-proof outer sealing membranes. Both the upper and lower lithium ion shuttling-proof outer sealing membranes are leak-proof insulating membranes. The intermediate elastomeric flame and explosion retardant membrane is a three-dimensional porous elastomeric membrane, and 0-60% of a flame retardant is adsorbed within the three-dimensional pores or on the outer surface of the three-dimensional porous elastomeric membrane.

[0053] The leakage-proof insulating film is any one or two of PP, PE, and PET films. The three-dimensional porous high-elastic membrane is a sponge or SBR rubber pad, and the flame retardant adsorbed on the outer surface of the three-dimensional pores of the three-dimensional porous high-elastic membrane is any one of a phosphorus-based flame retardant, a nitrogen-based flame retardant, or an inorganic flame retardant, aluminum hydroxide. The intermediate high-elastomer flame and explosion-retardant membrane is heat-sealed between the upper and lower lithium-ion shuttling-proof outer sealing films.

[0054] By providing the first coupled free energy balancing membrane 5 and the second coupled free energy balancing membrane 6, the exothermic reaction of the battery can be coupled and the membrane can be broken in the range of 120℃ to 180℃ to activate the reverse reaction to balance the chemical reaction free energy, further preventing thermal runaway. That is, the first coupled free energy balancing membrane 5 and the second coupled free energy balancing membrane 6 can couple the heat absorption while the battery releases a large amount of polarization heat, and break the membrane in the range of 120℃ to 180℃ to activate the battery's electrochemical reaction free energy balance function, preventing thermal runaway. By balancing the free energy within the battery cell, the stability and impact resistance of the battery cell are improved, reducing the risk of short circuit and explosion.

[0055] Figure 1 In the figure, three composite lithium battery papers 9 are stacked up and down in sequence, and each composite lithium battery paper 9 is separated by a second isolation membrane 15 and then connected in series to form a bare battery cell. The first coupling free energy balance membrane 5 is attached to the negative electrode active membrane 14 of the first composite lithium battery paper 9 above the bare battery cell, and the second coupling free energy balance membrane 6 is attached to the positive electrode active membrane 11 of the third composite lithium battery paper 9 below the bare battery cell.

[0056] In this embodiment, a first infusion tube 16 for electrolyte input and a second infusion tube 17 for electrolyte discharge and venting are installed on the upper sidewall of the battery cell compartment 2. After the battery cells are placed in the battery cell compartment 2, all gaps between the inner wall of the battery cell compartment 2 and the battery cells are filled with filler glue. The sealed inlet of the first infusion tube 16 and the outlet of the second infusion tube 17 are heat-sealed to directly convert them into safety explosion relief valves. The infusion port of the first infusion tube 16 and the outlet of the second infusion tube 17 are heat-sealed and can be punctured and self-sealed through the battery housing 1.

[0057] The battery shell 1 meets the IP68 protection standard, and the battery shell 1 can automatically heat failure and explosion relief when the internal pressure of the battery reaches a threshold, and can play a role in explosion-proof and water bubble-proof. Since the battery shell 1 is a non-closed container and must be open to the outside, after the battery cell is put into the battery cell bin 2, the filling glue must be used to fill all the gaps to achieve water-proof, air-proof and dew-proof. When the internal temperature of the battery shell 1 reaches 120℃-180℃, the pressure reaches 0.5Mpa-1Mpa, the filling glue fails, and the battery shell 1 is opened to release the explosion.

[0058] In this embodiment, the side wall of the device bin 3 is provided with a positive electrode terminal 18, a negative electrode terminal 19, and a CAN communication low-voltage power supply terminal 20; the positive electrode terminal, the negative electrode terminal, and the CAN connector of the built-in static repair management system 4 are respectively connected with the positive electrode terminal 18, the negative electrode terminal 19, and the CAN communication low-voltage power supply terminal 20 one by one.

[0059] In this step, the built-in static repair management system 4 is a product with a patent number 202222375993.3. The built-in static repair management system 4 includes a control circuit, a collection and operation circuit, and an operation power supply circuit. The operation power supply circuit is connected with the control circuit, the collection and operation circuit, and the battery or capacity unit (i.e. the composite lithium battery paper 9 in this step) in the NCE energy module; the control circuit is bidirectionally connected with the collection and operation circuit.

[0060] The positive electrode lug 7 in the battery cell connects the positive electrode current collector 10 of each positive electrode sheet in the bare battery cell with the positive electrode terminal (i.e. the charging and discharging positive electrode terminal P+) of the built-in static repair management system 4; the negative electrode lug 8 connects the negative electrode current collector 13 of each negative electrode sheet in the bare battery cell with the negative electrode terminal (i.e. the charging and discharging positive electrode terminal P+) of the built-in static repair management system 4. The specific connection relationship of the built-in static repair management system 4 is not described in detail here.

[0061] The built-in static repair management system 4 scans the voltage value of each composite lithium battery paper 9, takes the highest voltage value of the composite lithium battery paper 9 as the standard, and charges the remaining composite lithium battery papers 9 in turn to make the voltage reach the highest voltage value. In addition, the built-in static repair management system 4 has a unique code in its microprocessor MCU, left AFE chip, and right AFE chip, so it has an electronic identity card function for data tracing.

[0062] The built-in static repair management system 4 is used for static repair after the battery cell stops charging and discharging, to slow down the reversible capacity decay of the battery cell, thereby prolonging the service life of the battery and reducing the safety risk, and preventing overcharging and overdischarging caused by system misjudgment. The built-in static repair management system 4 also has an electronic identity card function, which is convenient for data tracing.

[0063] In this step, the battery casing 1, the first coupling free energy balance membrane 5, the second coupling free energy balance membrane 6 and the built-in static repair management system 4 form a complete and mutually coordinated battery safety system, so that the Anxin battery, as an energy aggregate, cannot release energy at a rapid rate and cause explosion under any circumstances.

[0064] Example 2 A method for preparing a safe core battery based on system safety

[0065] like Figure 2 As shown, this embodiment is a method for preparing a safe core battery based on system safety, comprising the following steps:

[0066] S1. The negative electrode sheet, the first separator 12 and the positive electrode sheet are sequentially stacked together, and then heat-compounded at 120° C. to 180° C. and pressurized at 0.3 MPa to 0.5 MPa to form a composite lithium battery paper 9.

[0067] S2. Make N composite lithium battery papers 9 into a bare battery cell; when N=1, the bare battery cell is a single composite lithium battery paper 9; when N≥2, stack the composite lithium battery papers 9 in sequence and separate them with a second isolation film 15 before combining them into one, and then connect the composite lithium battery papers 9 in series or in parallel to form a bare battery cell;

[0068] The bare cell is placed between the first coupling free energy balancing film 5 and the second coupling free energy balancing film 6, and is bonded to the surfaces of the first coupling free energy balancing film 5 and the second coupling free energy balancing film 6;

[0069] Each positive electrode sheet of the bare cell is connected to the positive terminal of the built-in static repair management system 4 through the positive electrode tab 7, and each negative electrode sheet of the bare cell is connected to the negative terminal of the built-in static repair management system 4 through the negative electrode tab 8 to form a safe bare cell.

[0070] In this step, the positive electrode sheet includes a positive electrode collector 10 for formatting the battery energy unit and a positive electrode active film 11 coated on the surface of the positive electrode collector 10, and the negative electrode sheet includes a negative electrode collector 13 for formatting the battery energy unit and a negative electrode active film 14 coated on the surface of the negative electrode collector 13; the positive electrode collector 10 is made of graphene, graphite or carbon nanotubes and breaks and cuts off the positive electrode electronic conductivity at a temperature of 120°C to 180°C; the negative electrode collector 13 is made of graphene, graphite or carbon nanotubes and breaks and cuts off the negative electrode electronic conductivity at a temperature of 120°C to 180°C.

[0071] Therefore, the specific process of step S2 is:

[0072] N composite lithium electric paper 9 is made into a bare battery core; when N = 1, the bare battery core is a single composite lithium electric paper 9; when N ≥ 2, each composite lithium electric paper 9 is stacked in turn and separated by a second isolation film 15, then combined into one, and then each composite lithium electric paper 9 is connected in series or parallel to form a bare battery core;

[0073] The bare battery core is arranged between the first coupling free energy balance film 5 and the second coupling free energy balance film 6, and is attached to the surface of the first coupling free energy balance film 5 and the second coupling free energy balance film 6.

[0074] The positive electrode tab 7 connects the positive electrode current collector 10 of each positive electrode sheet in the bare battery core to the positive electrode terminal of the built-in static repair management system 4, and the negative electrode tab 8 connects the negative electrode current collector 13 of each negative electrode sheet in the bare battery core to the negative electrode terminal of the built-in static repair management system 4.

[0075] S3, the safety bare battery core is installed in the battery core compartment 2 of the battery shell 1, and the first infusion tube 16 and the second infusion tube 17 are arranged; the built-in static repair management system 4 is installed in the equipment compartment 3 of the battery shell 1, and the positive electrode terminal, the negative electrode terminal and the CAN connector of the built-in static repair management system 4 are respectively connected to the positive electrode terminal 18, the negative electrode terminal 19 and the CAN communication low-voltage power supply terminal 20 one by one.

[0076] S4, all the gaps between the inner wall of the battery core compartment 2 and the safety bare battery core are filled with filling glue, and then electrolyte is input by an external electrolyte filling machine through the first infusion tube 16 and the second infusion tube 17 to form a battery core.

[0077] During the input of the electrolyte, the infusion port of the first infusion tube 16 is connected to the electrolyte filling machine to input the electrolyte, the outlet of the second infusion tube 17 is exhausted, and the electrolyte filling machine quantitatively infuses, and when the preset liquid level is reached, the electrolyte filling machine stops infusion.

[0078] S5, the positive electrode terminal 18, the negative electrode terminal 19 and the CAN communication low-voltage power supply terminal 20 are respectively connected to the corresponding terminal of the external high-voltage charging and discharging cabinet, and then the battery core is charged and discharged to form a safety battery based on system safety.

[0079] Comparative example

[0080] In order to prove the effect of the embodiment, five groups of safety batteries based on system safety are prepared in the embodiment. Among them, the material of the positive electrode current collector 10 is graphene, and the material of the negative electrode current collector 13 is graphite.

[0081] The first group is prepared by hot compounding at 120℃ under 0.4MPa pressure to obtain the composite lithium battery paper 9; the second group is prepared by hot compounding at 135℃ under 0.5MPa pressure to obtain the composite lithium battery paper 9; the third group is prepared by hot compounding at 180℃ under 0.35MPa pressure to obtain the composite lithium battery paper 9; the fourth group is prepared by hot compounding at 165℃ under 0.3MPa pressure to obtain the composite lithium battery paper 9; and the fifth group is prepared by hot compounding at 148℃ under 0.45MPa pressure to obtain the composite lithium battery paper 9; then each group is made into a bare battery cell by connecting three composite lithium battery papers 9 in series to obtain a safety battery cell based on the system.

[0082] The five groups of safety battery cells based on the system are respectively taken as Comparative Examples 1 of each group by removing the first coupled free energy balance film 5 and the second coupled free energy balance film 6 from the batteries.

[0083] The five groups of safety battery cells based on the system are respectively taken as Comparative Examples 2 of each group by replacing the material of the positive current collector 10 with aluminum foil and the material of the negative current collector 13 with copper foil.

[0084] The five groups of safety battery cells based on the system are respectively taken as Comparative Examples 3 of each group by replacing the built-in static repair management system 4 with a LUNA2000-10KW-C1 battery management system.

[0085] The batteries prepared in M1-M5 and Comparative Examples are subjected to safety tests according to the safety requirements and test methods for lithium ion batteries GB-T31485-2015 power storage batteries for electric vehicles.

[0086] Overcharge test: the battery is charged at 1C constant current and constant voltage, and the cutoff current is 0.05C; then the battery is charged at 1C constant current to 1.5-2 times the rated voltage of the battery; the change of the surface temperature of the battery cell is observed for 1h, and whether the battery cell ignites and explodes is recorded.

[0087] Puncture test: the battery is punctured with a 5mm diameter steel needle in the direction perpendicular to the positive and negative current collectors of the composite lithium battery paper, and the temperature of the surface of the battery cell is monitored during the process, and whether the battery cell ignites and explodes is recorded.

[0088] The overcharge and puncture test results are as follows:

[0089] Table 1 Comparison of overcharge test results

[0090] Group Cell surface temperature / °C Whether the battery is swollen Whether the battery is on fire, explosion Battery pass rate M1 70 Micro-swelling No 100％ M1 Comparative Example 1 97 Swelling No 100％ M1 Comparative Example 2 88 Swelling No 100％ M1 Comparative Example 3 80 Swelling No 100％ M2 72 Micro-swelling No 100％ M2 Comparative Example 1 100 Swelling No 100％ M2 Comparative Example 2 86 Swelling No 100％ M2 Comparative Example 3 85 Swelling No 100％ M3 80 Micro-swelling No 100％ M3 Comparative Example 1 98 Swelling No 100％ M3 Comparative Example 2 77 Swelling No 100％ M3 Comparative Example 3 90 Swelling No 100％ M4 78 Micro-swelling No 100％ M4 Comparative Example 1 101 Swelling No 100％ M4 Comparative Example 2 80 Swelling No 100％ M4 Comparative Example 3 90 Swelling No 100％ M5 85 Micro-swelling No 100％ M5 Comparative Example 1 102 Swelling No 100％ M5 Comparative Example 2 77 Swelling No 100％ M5 Comparative Example 3 90 Swelling No 100％

[0091] Table 2 Puncture test results

[0092]

[0093]

[0094] From Table 1 and Table 2, it can be seen that in the safe battery system prepared in the embodiment, the battery shell 1, the first coupled free energy balance film 5, the second coupled free energy balance film 6 and the built-in static repair management system 4 form a complete and mutually cooperative battery safety system, so that the safe battery as an energy aggregate cannot release energy at a high speed to cause combustion and explosion under any circumstances.

[0095] It should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the above embodiments of the present application have been described in detail, those skilled in the art can still modify the technical solutions recorded in the above embodiments or equivalently replace some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A safe core battery based on system safety, comprising a battery housing with an internal storage space and a battery cell, wherein the interior of the battery housing is divided into a battery cell compartment and an equipment compartment, and the battery cell is installed in the battery cell compartment; characterized in that: It also includes a built-in static repair management system for statically repairing the reversible capacity attenuation of the battery cell after the battery cell stops charging and discharging, preventing the system from misjudging overcharge and over-discharge, and having an electronic ID card function for data traceability. The built-in static repair management system is installed in the equipment compartment; The battery cell comprises a first coupling free energy balancing membrane, a second coupling free energy balancing membrane, a bare battery cell, an electrolyte, a positive electrode tab, and a negative electrode tab; the bare battery cell comprises N composite lithium battery papers, N ≥ 1, and N is an integer; the composite lithium battery paper is obtained by sequentially stacking and assembling a negative electrode sheet, a first isolation membrane, and a positive electrode sheet into one body; When N=1, a bare cell is formed by a single composite lithium battery paper; when N≥2, individual composite lithium battery papers are stacked in sequence and separated by a second isolation membrane before being combined into a whole, and the composite lithium battery papers are connected in series or in parallel to form a bare cell; the bare cell is disposed between the first coupling free energy balancing membrane and the second coupling free energy balancing membrane, and is bonded to the surfaces of the first coupling free energy balancing membrane and the second coupling free energy balancing membrane; The positive electrode tab connects each positive electrode sheet of the bare cell to the positive terminal of the built-in static repair management system, and the negative electrode tab connects each negative electrode sheet of the bare cell to the negative terminal of the built-in static repair management system to form a safe bare cell; A first infusion tube for inputting electrolyte and a second infusion tube for discharging liquid and exhausting gas are installed on the upper side wall of the battery cell compartment; a positive terminal, a negative terminal, and a CAN communication low-voltage power supply terminal are installed on the side wall of the equipment compartment; the positive terminal, negative terminal, and CAN connector of the built-in static repair management system itself are respectively connected one-to-one with the positive terminal, negative terminal, and CAN communication low-voltage power supply terminal.

2. The safe-core battery based on system safety according to claim 1, characterized in that: The positive electrode sheet includes a positive electrode current collector for formatting the battery energy unit and a positive electrode active film coated on the surface of the positive electrode current collector, and the negative electrode sheet includes a negative electrode current collector for formatting the battery energy unit and a negative electrode active film coated on the surface of the negative electrode current collector; The positive electrode tab connects the positive electrode collector of each positive electrode sheet in the bare battery cell to the positive terminal of the built-in static repair management system, and the negative electrode tab connects the negative electrode collector of each negative electrode sheet in the bare battery cell to the negative terminal of the built-in static repair management system.

3. The safe core battery based on system safety according to claim 2, characterized in that: The positive electrode current collector is made of graphene, graphite or carbon nanotubes and breaks at 120°C to 180°C to cut off the positive electrode electronic conduction; The negative electrode current collector is made of graphene, graphite or carbon nanotubes and breaks at 120°C to 180°C to cut off the negative electrode electronic conduction.

4. The safe-core battery based on system safety according to claim 1, characterized in that: The first coupling free energy balance membrane and the second coupling free energy balance membrane have the same structure, and both include an upper lithium ion shuttling prevention outer sealing membrane, a lower lithium ion shuttling prevention outer sealing membrane, and an intermediate high-elastic flame-stopping and explosion-stopping membrane sealed between the upper lithium ion shuttling prevention outer sealing membrane and the lower lithium ion shuttling prevention outer sealing membrane; Among them, the upper anti-lithium ion shuttle outer sealing membrane and the lower anti-lithium ion shuttle outer sealing membrane are both leakage-proof insulating membranes; the middle elastomer flame retardant and explosion-stopping membrane is a three-dimensional porous high-elastic membrane, and 0 to 60% of the flame retardant is adsorbed in the three-dimensional pores or on the outer surface of the three-dimensional porous high-elastic membrane.

5. The safe core battery based on system safety according to claim 1, characterized in that: Filling glue is used to fill all gaps between the inner wall of the battery cell compartment and the battery cells. The infusion port of the first infusion tube and the outlet of the second infusion tube are heat-sealed and directly converted into safety explosion relief valves.

6. The safe-core battery based on system safety according to claim 5, characterized in that: When the internal temperature of the battery shell reaches 120° C. to 180° C. and the pressure reaches 0.5 MPa to 1 MPa, the filling glue fails and the battery shell opens and explodes.

7. A method for preparing a safe core battery based on system safety according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, stacking the negative electrode sheet, the first separator and the positive electrode sheet in sequence into one body, and thermally compounding them under the conditions of heating at 120°C to 180°C and pressurizing at 0.3MPa to 0.5MPa to form a composite lithium battery paper; S2. Making N composite lithium battery papers into a bare battery cell; when N=1, the bare battery cell is a single composite lithium battery paper; when N≥2, stacking the composite lithium battery papers in sequence and separating them with a second isolation film, then combining them into one, and then connecting the composite lithium battery papers in series or in parallel to form a bare battery cell; The bare battery cell is arranged between the first coupling free energy balancing membrane and the second coupling free energy balancing membrane, and is bonded to the surfaces of the first coupling free energy balancing membrane and the second coupling free energy balancing membrane; Connect each positive electrode sheet of the bare cell to the positive terminal of the built-in static repair management system through the positive electrode tab, and connect each negative electrode sheet of the bare cell to the negative terminal of the built-in static repair management system through the negative electrode tab to form a safe bare cell; S3. Install the safe bare battery cell in the battery cell compartment of the battery housing and set a first infusion tube and a second infusion tube; install the built-in static repair management system in the equipment compartment of the battery housing, and connect the positive terminal, negative terminal, and CAN connector of the built-in static repair management system to the positive terminal, negative terminal, and CAN communication low-voltage power supply terminal in a one-to-one correspondence; S4. All gaps between the inner wall of the battery cell compartment and the safety bare battery cell are sealed with filling glue, and then electrolyte is introduced through the first infusion tube and the second infusion tube to form a battery cell; S5. Charge and discharge the battery cell through the positive terminal, the negative terminal, and the CAN communication low-voltage power terminal, and heat-seal the infusion port of the first infusion tube and the outlet of the second infusion tube to manufacture a safe core battery based on system safety.

8. The method for preparing a safe core battery based on system safety according to claim 7, characterized in that: The positive electrode sheet includes a positive electrode current collector for formatting the battery energy unit and a positive electrode active film coated on the surface of the positive electrode current collector, and the negative electrode sheet includes a negative electrode current collector for formatting the battery energy unit and a negative electrode active film coated on the surface of the negative electrode current collector; The specific process of step S2 is: N composite lithium battery papers are made into a bare battery cell; when N=1, the bare battery cell is a single composite lithium battery paper; when N≥2, the composite lithium battery papers are stacked in sequence and separated by a second isolation film before being combined into a whole, and then the composite lithium battery papers are connected in series or in parallel to form a bare battery cell; The bare battery cell is arranged between the first coupling free energy balancing membrane and the second coupling free energy balancing membrane, and is bonded to the surfaces of the first coupling free energy balancing membrane and the second coupling free energy balancing membrane; The positive electrode collector of each positive electrode sheet in the bare battery cell is connected to the positive terminal of the built-in static repair management system through the positive electrode tab, and the negative electrode collector of each negative electrode sheet in the bare battery cell is connected to the negative terminal of the built-in static repair management system through the negative electrode tab.

9. The method for preparing a safe core battery based on system safety according to claim 7, characterized in that: The positive electrode current collector is made of graphene, graphite or carbon nanotubes and breaks at 120°C to 180°C to cut off the positive electrode electronic conduction; The negative electrode current collector is made of graphene, graphite or carbon nanotubes and breaks at 120°C to 180°C to cut off the negative electrode electronic conduction.

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