375results about How to "Avoid thermal runaway" patented technology

The invention provides a lithium ion battery diaphragm and a high temperature thermal-stable lithium ion battery, which relate to lithium ion batteries. The diaphragm comprises a polyolefin microporous membrane which acts as a basic layer, wherein a nano ceramic material coating is manufactured on one side surface or two side surfaces of the polyolefin microporous membrane; and compositions of the nano ceramic material coating comprise any one of a zirconium oxide, an aluminum oxide, a silicon oxide, a titanium oxide, a silicon nitride, a boron nitride and an aluminum nitride or a combination of any oxide and any nitride, and additionally comprise binders. Since a high temperature resistant nano ceramic material is led into the surface of a conventional diaphragm, an insulating property better than the insulating property of the conventional diaphragm is provided, further internal insulating property damage brought by thermal contraction of the conventional diaphragm, which leads to thermal runaway of the lithium battery, is avoided particularly at high temperatures of 130 DEG C, 150 DEG C and 180 DEG C, and thereby the high temperature thermal stability of the lithium ion battery is improved and the safe reliability of the lithium ion battery is increased.

The invention relates to a novel ceramic coating polyolefin composite film which comprises a polyolefin substrate with micro pores, wherein one side or both sides of the polyolefin substrate is / are compounded with ceramic coating(s); the ceramic coating comprises porous ceramic particles, an inorganic filler and an adhesive. The invention also relates to a method for preparing the novel ceramic coating polyolefin composite film. The method comprises the following steps: a, dissolving the adhesive in a solvent, thereby preparing an adhesive solution; b, adding the porous ceramic particles and the functional inorganic filler into the adhesion solution prepared in the step a, and performing dispersing treatment, thereby preparing coating slurry; and c, coating one or two surfaces of the polyolefin substrate with the coating slurry prepared in the step b, and drying and curing to prepare the product. The novel functional composite film has high liquid absorption and retention performance, has the functions of reducing harmful gases inside a battery, improving the performance of the battery and prolonging the service life of the battery, and has the safety characteristics of low closed pore temperature, high melting temperature and low hot-shrinkage rate.

The invention relates to the technical field of battery charging, in particular to a charging method of a lithium ion battery based on time and temperature. Polarization voltage limited maximum charging current is calculated based on lithium ion battery polarization characteristics, and under the constraint of the maximum charging current, charging temperature rise and charging time are considered comprehensively, genetic algorithm is employed to search the optimal charging current so as to balance the mutual contradictory objects of reducing charging time and lowering charging temperature rise. The result shows that the optimal charging current ensures charging rapidity, at the same time controls the polarization voltage and temperature rise of the charging process within an allowable range, and guarantees the charging capacity, charging efficiency and charging safety and battery life.

The invention specifically relates to a high-voltage lithium ion battery electrolyte, which belongs to the technical field of lithium ion battery electrolytes. The high-voltage lithium ion battery electrolyte provided by the invention comprises a non-aqueous solvent, a lithium salt and an additive, wherein the additive comprises a mixture of a fluoro-ether additive and an alkyl dinitrile additive. A lithium ion battery using the high-voltage lithium ion battery electrolyte has stable cycle performance at normal temperature, no gas generation at a high temperature condition and small changes of internal resistance. A preparation process for the high-voltage lithium ion battery electrolyte is simple and easy to implement and has good market prospects.

The invention belongs to the technical field of power batteries, and especially relates to a power battery top cover and a power battery using the top cover. The power battery top cover comprises a top cover sheet, and a firs pole pillar, a second pole pillar, a pressure release valve, a liquid injection hole, pneumatic overturning sheets and a resistor block, the first pole pillar is in insulation connection with the top cover sheet, the second pole pillar is electrically connected with the top cover sheet through the resistor block, the pneumatic overturning sheets are electrically connected with the top cover sheet, the conductive block is arranged above the pneumatic overturning sheets, a baffle plate is arranged under the pressure release valve, the pneumatic overturning sheets comprise a first pneumatic overturning sheet and a second pneumatic overturning sheet, and the thickness of the first pneumatic overturning sheet is smaller than the thickness of the second pneumatic overturning sheet; and when the pressure in the power battery increases, the pneumatic overturning sheet and the second pneumatic overturning sheet sequentially move upward in order to electrically connect the first pole pillar with the second pole pillar. Compared with power battery top covers in the prior art, the power battery top cover disclosed in the invention makes the power battery have an excellent safety protection function in overcharging, nailing, short circuit and hot box test.

Disclosed is a charging machine including a main charging circuit and a charging control circuit, the main charging circuit comprises a filter circuit, a rectifier filter circuit, a pulse bleeder circuit, a half-bridge inversion circuit, a drive control circuit and a high frequency rectifier charging circuit, the charging control circuit comprises a power supply circuit, a voltage stabilizing circuit, a self-recycle circuit, a current detecting circuit, a voltage detecting circuit and a temperature detecting circuit, and the charging control circuit also comprises a control display circuit and a pulse modulation switching power supply integrating control circuit. The charging machine can effectively release the sulfation phenomenon of a battery plate by controlling a single chip microcomputer in the control display circuit to adopt multi-stage pulse type charging method, fives stages including constant current, constant voltage, floating charge I, average charge and floating charge II. Each stage in process outputs different duty cycle pulsing signal through the control of single chip microcomputer and then a half-bridge power tube is controlled to reach intermittent pulse current charge and depolarization effect.

The invention relates to a lithium ion battery composite diaphragm, a preparation method thereof and a lithium ion battery, and belongs to the technical field of lithium ion batteries. The lithium ion battery composite diaphragm comprises a diaphragm matrix, wherein the diaphragm matrix is a polyolefin microporous membrane or a polyolefin microporous membrane whose surface is coated with a ceramic layer; a surface of the diaphragm matrix is coated with a lithium supplementing layer; and the lithium supplementing layer contains lithium powder. According to the lithium ion battery composite diaphragm, the surface of the diaphragm is provided with the lithium supplementing layer, lithium required for forming an SEI (Solid Electrolyte Interface) film is filled up, supplementationis provided for lithium ions consumed by formation of the SEI film on a surface of a negative pole piece, the irreversible capacity of the lithium ion battery is reduced, and the initial efficiency, the cycle performance and the energy density of the lithium ion battery are improved.

The invention relates to a method for monitoring thermal runaway of a lithium ion battery of an electric vehicle. A voltage changing rate parameter when thermal runaway occurs in the lithium ion battery is monitored, and a battery voltage can be reduced abruptly, is maintained at a low voltage for 40-60 seconds and then is gradually raised to an initial voltage when the thermal runway occurs in the lithium ion battery; the fact that thermal runaway occurs in the battery can be judged by taking the battery voltage changing rate parameter as a monitoring object and is a first judgment method; abattery temperature rising rate changing parameter is monitored, the fact that thermal runaway occurs in the battery also can be judged when the battery temperature rising rate is larger than or equalto 10 DEG C per minute and is a second judgment method; and a battery management system (BMS) is used for monitoring, analyzing and judging the battery voltage changing parameter and the battery temperature rising rate parameter, the two methods are used as an independent condition or a logic combination condition and used as a technological basis for judgment on thermal runaway of the battery, and an early-warning signal can be given out in advance when thermal runaway occurs. By the method, the battery thermal runaway judgment time is greatly increased, and enough handling time is providedfor a person to escape and timely take a measure to prevent battery thermal runaway from being generated, propagating and being expanded.

The invention aims to solve the technical problem of fire or explosion of batteries and provides a high-safety lithium ion battery which can radically realize fire resistance and explosion prevention. The high-safety lithium ion battery comprises a positive pole piece, a diaphragm and a negative pole piece, wherein the diaphragm is positioned between the positive pole piece and the negative pole piece; the positive pole piece comprises a positive-pole current collector and positive pole pulp, and the positive pole pulp is coated on the positive-pole current collector; the negative pole piece comprises a negative-pole current collector and negative pole pulp, and the negative pole pulp is coated on the negative-pole current collector; and the positive pole pulp and / or the negative pole pulp comprises a conductive agent which is a high-polymer thermosensitive material with positive temperature coefficients. In the pole piece added with the high-polymer thermosensitive material with positive temperature coefficients, under uncommon conditions, when current or temperature rises sharply, the specific resistance follows to rise, thus a conductive network is destroyed, thermal runaway generated by batteries is prevented and a preventative effect is played on the thermal runaway of the lithium ion batteries. The invention greatly increases the safety performance of the lithium ion battery and can radically solve the safety problem of batteries.

The invention discloses a composite ceramic membrane for lithium ion batteries and a preparation method thereof, including a ceramic coating modification method and a ceramic lithium battery membrane. The ceramic protective layer is mainly prepared from a ceramic-adhesive mixture subjected to graft modification by a sodium-sulfonate / sodium-carboxylate-group-containing anionic surfactant. The grafting is completed by using a grafting-on process under the action of a coupling agent; the grafting ratio of the ceramic is higher; the high-temperature-resistant large-surface-area nano ceramic is introduced to the conventional PP (polypropylene) membrane surface, the insulativity and electrolyte wettability of the modified ceramic membrane are greatly enhanced; and the membrane has excellent high-temperature heat stability especially at the high temperature of 130 DEG C, 150 DEG C and 180 DEG C. The lithium battery composite membrane avoids the thermal shrinkage of the convention membrane, thereby avoids the thermorunaway in the battery due to thermal shrinkage, and further enhancing the safe reliability of the lithium ion battery.

A diaphragm is disclosed, which comprises a porous diaphragm substrate and a heat-sensitive coating coated on at least one surface of the diaphragm substrate, wherein the heat-sensitive coating comprises 10 to 90 wt.% of thermal expansion microspheres and 3 to 15 wt.% of an adhesive, and the thermal expansion microsphere comprises a blowing agent and a thermoplastic polymer shell encapsulating theblowing agent. Compared with the prior art, the diaphragm of the present invention can prevent the occurrence of thermal runaway of the battery and remarkably improve the safety of the lithium ion battery by coating the heat-sensitive coating containing thermal expansion microspheres on the surface of the diaphragm. In addition, the invention also discloses a preparation method of the diaphragm and a lithium ion battery using the diaphragm.

The invention discloses a method for charging a battery of an electric road vehicle. The method comprises the following steps of: (1) pre-charging; (2) A-period constant current charging; (3) B-period constant current charging; (4) constant voltage charging; (5) double-threshold charging; and (6) float charging, wherein the base number of the charging environment temperature is 25 DEG C, current and voltage in the whole charging process are adjusted in inverse proportion to the environment temperature, a current adjustment coefficient is 30 to 80 mA / DEG C, a voltage adjustment coefficient in the step (6) is 3 to 4 mV / monomer.DEG C, and a voltage adjustment coefficient in other steps is 5 to 6 mV / monomer.DEG C. By adjusting charging parameters under different temperature conditions, a charging effect of the battery at different temperatures is ensured, and the service life of the battery is prolonged.

The invention relates to a cylindrical battery. The cylindrical battery comprises a shell, a battery cell, a pole, a cover plate, a positive collector plate and a negative collector plate, the shell is of a cylindrical groove structure, and the battery cell, the positive collector plate and the negative collector plate are all arranged in the shell. The cover plate is connected with the notch of the shell. The pole is riveted with the shell, the pole penetrates into the shell from the bottom end face of the shell, and an insulating sealing piece is arranged between the pole and the shell. The battery cell is of a full-tab structure, the two end faces of the battery cell are connected with the positive collector plate and the negative collector plate respectively, the end, located in the shell, of the pole is electrically connected with the battery cell through the positive collector plate, and the shell is electrically connected with the negative collector plate. The invention also relates to a battery module. The battery module comprises the cylindrical battery. The invention also relates to a battery pack. The battery pack comprises the battery module.

The present invention relates to the technical field of secondary battery pack manufacturing, and provides a high specific energy battery pack internal flame-retardant cooling method. According to the method, a flame retardant agent is subjected to a microencapsulation treatment and the treated flame retardant agent is filled inside the battery pack, such that the problem that the sharp temperature change caused by the electrical core short circuit and other failures causes firing burning even explosion can be solved. According to the present invention, the method has the following effects that after the temperature in the battery pack is increased to a certain value, the shell of the microcapsule filled with the flame retardant agent is rapidly dissolved or broken to release the flame retardant agent, and oxygen is consumed or diluted through the physical pathway of the isolation film forming on the local high-temperature area and the surrounding in the battery pack and the chemical pathway of the free radical terminating so as to achieve the functions of flame retardant effect and cooling, terminate the spreading of the high temperature area, eliminate and reduce the firing risk, and improve the safety performance of the battery pack; and the method has advantages of high safety and high reliability, and with the microcapsule flame retardant agent, the installation of the larger fire extinguishing device is avoided, and the advantages of lightweight and environmental protection are provided.

The invention belongs to the technical field of charging of a lithium ion battery, and particularly relates to an optimized charging method of a vehicle-mounted energy storage lithium ion battery for rail transit. The optimized charging method comprises the steps of calculating maximum charging current and a charging cutoff voltage of a lithium ion battery within a full-life period according to cycle lifetime attenuation characteristic of the lithium ion battery; constructing an optimized charging target function under the constraint of the maximum charging current and the charging cutoff voltage by taking charging time reduction and battery charging temperature rising control as targets; and seeking an optimal charging current by a genetic algorithm so as to balance the two conflict targets of charging time reduction and the charging temperature rising reduction. A result shows that the optimal charging current is used for ensuring charging rapidness and simultaneously controlling a polarization voltage and the temperature rising during the charging process to be within allowable ranges, and the charging capacity, the charging efficiency, the charging safety and the battery lifetime are ensured.

The invention provides a lithium battery diaphragm for power vehicles. The diaphragm has four layers, the layers are respectively from bottom to top a base diaphragm, a nanometer flame retarding layer, an electrospun nanofiber layer and a thermal closed layer, wherein the base diaphragm is a PET nuclear pore membrane with a thickness of 5 microns-20 microns, the nano meter flame retardant layer is a flame retardant ceramic slurry with a thickness of 0.5 micron-10 microns, the thickness of the electrospun nano-fiber layer is 2 microns-5 microns, and the heat closed layer is a heat-resistant epoxy resin with a thickness of 5 microns-10 microns. The invention also provides a preparation method of the lithium battery diaphragm; the heat-resistance and shrinkage performance of the prepared lithium battery diaphragm can be greatly improved, the thermal stability and thermal closed property are significantly improved, and the security is very good.

The invention provides a safe and energy-saving lithium battery pack dual-mode thermal management system and method. The system comprises a battery pack, a battery pack shell, a liquid-cooling tube heat exchanger, and an external air-cooling fin with a fan. A micro heat pipe array is attached to the surface of a battery or a battery module, and a protruding portion of the micro heat pipe array isattached to the battery pack shell. The liquid-cooling tube heat exchanger is attached to the outer surface of the battery pack shell and is connected to an electric vehicle refrigeration system, anda substrate of the external air-cooling fin is attached to the outside of the liquid-cooling tube heat exchanger. According to the invention, the micro heat pipe array with high heat transfer and aircooling and liquid cooling modes are effectively combined, on one hand, the heat inside the battery can be effectively transmitted to the outside, the temperature is prevented from being too high, theuniform temperature of the battery is ensured, the heat dissipation efficiency is high, on the other hand, different systems are started in different states and temperatures, and the avoidance of thermal runaway and substantial energy savings are achieved.

The invention relates to a preheating charging loss optimization battery pack charging method in the low-temperature environment and in particular relates to a battery pack charging method. The preheating charging loss optimization battery pack charging method aims to optimize energy consumption of preheating process of the charging process and energy loss of charging process of a battery pack in the low-temperature environment. The preheating charging loss optimization battery pack charging method is characterized by comprising the following steps: preheating the battery pack in the low-temperature environment, so that the charging performance of the battery pack is recovered, and determining preheating target temperature and battery pack constant current charging current by utilizing a modern data optimization algorithm, taking battery preheating target temperature and battery charging current as solving quantity and taking minimum energy consumption of preheating and charging processes as a target according to the charging current and the working temperature range provided by a battery manufacturer. By utilizing the preheating charging loss optimization battery pack charging method, the low temperature service ability of the battery pack can be effectively improved.

The invention provides an internal oxygen self-absorption safe lithium battery. The lithium battery comprises a positive electrode sheet and a negative electrode sheet. The positive electrode sheet ismade of raw materials in following parts by weight: 90to 97 parts of a positive electrode active material, 0.5 to 4 parts of a positive electrode conductive agent 0.5 to 3 parts of a positive electrode binder and 15 to 70 parts of a positive solvent; the positive electrode sheet further comprises an oxygen absorption additive, wherein the addition amount of an oxygen absorption additive is 0.01%to 10% of the total amount of the positive electrode active material, the positive electrode conductive agent and the positive electrode binder. The internal oxygen self-absorption safe lithium battery of the invention is characterized in that the oxygen absorption additive uniformly mixed in a positive electrode material, when the positive elctrode active material is decomposed and releases oxygen at high temperature, the surrounding oxygen can be quickly captured, the oxygen concentration in the lithium battery when the lithium battery is out of control is reduced, so that the lithium battery cannot meet the ignition conditions, and the lithium battery is prevented from thermal runaway fire.

The invention provides a phase change composite, a preparation method and an application. The phase change composite is prepared from paraffin powder, expanded graphite powder, polyethylene particlesand SEBS. By adopting a material system in a special ratio, the defects that the conventional phase change energy storage material is low in thermal conductivity and required to be encapsulated in practical use to prevent leakage are overcome, thermal management efficiency is increased greatly, and popularization and application range of the phase change energy storage material is expanded.

The invention discloses a phenolic resin modified ceramic diaphragm and application thereof. The diaphragm comprises porous base film, at least one side of the film is provided with a phenolic resin ceramic layer by spreading a phenolic resin ceramic slurry; at least one surface of the porous base film is coated with the ceramic layer, and the surface of the ceramic layer, the insides of pores, the insides of the pores of the porous base film and the surface which is not coated with the ceramic layer are immersed in a phenolic resin precursor solution to be subjected to the in-situ polymerization to form the phenolic resin layer. Through the mixing coating of the phenolic resin and the ceramic slurry or the in-situ polymerizing of the phenolic resin on the basis of the ceramic diaphragm, aphenolic resin ceramic mixed layer can be formed on the surface of the porous base film, the surface of the porous base film and the insides of the pores are coated with the in-situ coating phenolicresin layer, thereby improving the thermal stability of the diaphragm, the diaphragm does not shrink at 200 DEG C and still maintains strong mechanical strength, the contact of the positive and negative electrodes is effectively blocked, and the safety performance of a battery is ensured.

The invention provides a microcapsule, comprising a capsule shell portion and a capsule core portion that is selected from one or both of an organic flame retardant and an inorganic flame retardant, wherein the outer surface of the capsule shell portion has a pile structure, and the capsule shell portion is made of polymer material. The application also provides a method of preparing the microcapsule, and a lithium ion battery. The microcapsule provided by the application is applied to the lithium ion battery, which can improve the safety of the lithium ion battery without affecting the electrochemical performance of the lithium ion battery.

The invention discloses a high-temperature-resistant polymer modified ceramic diaphragm and an application thereof. The high-temperature-resistant polymer modified ceramic diaphragm comprises a porousbase membrane, and at least one surface of the porous base membrane is coated with a ceramic layer; and a high-temperature-resistant polymer layer is arranged on the surface and in the interior of pores of the ceramic layer, in the interior of pores of the porous base membrane, and on the surface not coated with the ceramic layer in an in-situ polymerization manner. The high-temperature-resistantpolymer modified ceramic diaphragm has relatively high thermal stability. Through the in-situ polymerization method of pyrrole, the thiophene and the aniline monomer, a high-temperature-resistant polymer protection layer is formed on the surface and in the interior of pores of the ceramic layer, on the surface of the porous base membrane, and in the pores in an in-situ coating manner, so that theceramic layer, the polymer layer and the base membrane form an organic integrated body; therefore, the thermal size stability of the modified ceramic diaphragm is improved, and the modified ceramic diaphragm does not contract at a high temperature of 200 DEG C; and in addition, relatively high mechanical performance is still kept, positive and negative electrode contact can be effectively obstructed, and the safety performance of the battery can be guaranteed.

The invention provides a vehicle and a cooling method and device for a power battery of the vehicle. The method comprises the following steps of obtaining the current driving working condition of thevehicle, the currently adopted driving mode and the target state of the current environment; determining an estimated temperature coefficient of a power battery in the vehicle according to the drivingworking condition, the driving mode and the target state; obtaining the current temperature of the power battery, and obtaining the estimated temperature of the power battery according to the currenttemperature and the estimated temperature coefficient; and performing cooling control on the power battery according to the estimated temperature. According to the cooling method disclosed by the invention, the power battery can be pre-estimated by combining the driving condition, the driving mode, the current temperature and the temperature of the power battery of the vehicle, and the battery isprevented from being cooled and controlled only according to the acquired temperature, so that the battery life attenuation and the energy consumption are reduced, and the battery discharge capacityis kept optimal; and the problem of untimely cooling caused by temperature acquisition lag and the phenomenon of thermal runaway caused by heating of the battery are prevented.

The invention relates to the field of battery energy storage system security, in particular to the field of power battery security. An emergency refrigerating device for a battery energy storage system adopts liquid nitrogen phase-change refrigeration, and comprises a nitrogen generator, a liquid nitrogen container, a cooling pipe, a cooling valve, refrigerating passages and a pressure release valve. The nitrogen generator is used for nitrogen generation and cooling storage during battery charging. A rechargeable micro battery supplies power for the cooling valve, and the controller is provided with an independent signal collecting and logic processing mechanism without depending on a battery management system (BMS); and the controller comprises a vibration sensor which can sense the accidents such as collision and explosion. A closed refrigerating passage is generally mounted on a heat-dissipation module of the battery, and the heat of the battery is dissipated through the heat-dissipation module. An open refrigerating passage is mounted on the battery, and a plurality of small holes formed in the part, close to the battery, of the pipeline are used for uniformly spraying liquid nitrogen onto the battery. The emergency refrigerating device has the beneficial effects that the liquid nitrogen is used for emergency refrigeration, and can reach the effect of quick cooling, so that thermal runaway of a battery pack is prevented, and a thermal runaway chain reaction is avoided to the maximum extent.

The invention provides a preparation method of a high-conductivity graphene / carbon nanotube composite coating for lithium ion batteries, including the following steps: (1) preparing graphene oxide solution; (2) preparing nano-silicon solution; (3) preparing uniform graphene oxide / nano-silicon mixed solution; (4) preparing uniform and stable graphene oxide / nano-silicon / carbon nanotube mixed solution; (5) preparing graphene / nano-silicon / carbon nanotube mixed solution; (6) preparing coating slurry; and (7) coating a current collector with the coating slurry obtained in step (6), and drying the coating slurry to obtain a high-conductivity graphene / carbon nanotube composite coating for lithium ion batteries. The preparation method of a high-conductivity graphene / carbon nanotube composite coating for lithium ion batteries in the invention is safe, environment-friendly and stable, can significantly improve the electrochemical performance of lithium ion batteries and avoid the phenomenon of graphene agglomeration, and is conducive to the composition with carbon nanotubes.

The invention discloses a water-based conducting sizing agent for coating on the surface of the current collector of a high-safety lithium battery. The water-based conducing sizing agent is prepared from the following components in percentages by weight: 0.5% to 15% of a conducting material, 0.5% to 10% of a dispersing agent, 0.2% to 2% of cellulose, 0.1% to 1% of a wetting agent, 2% to 20% of an adhesive, 0.5% to 10% of a polyolefin microballoon emulsion and the balance of deionized water. The invention also discloses a preparation method of the water-based conducting sizing agent and a method for using the water-based conducting sizing agent on the current collector of the high-safety lithium battery. According to the water-based conducting sizing agent disclosed by the invention, thermal runaway can be effectively prevented, so that the safety of the battery is improved; the adhesive force between a positive material and an aluminum foil and the adhesive force between a negative material and a copper foil are improved, and the proportion of the positive adhesive or the negative adhesive is reduced, so that the energy density of the battery is improved, and the endurance mileage is increased; simultaneously, the internal resistance of the battery is greatly reduced, dynamic internal resistance consistency of the battery is improved, and the service life of the battery pack is prolonged; the electrical conductivity of the positive material and the aluminum foil and the electrical conductivity of the negative material and the copper foil are strengthened, and the charging capacity and discharging capacity are quickly improved.