Thermal Shutdown Separators and Ceramic Coatings for EV Battery

Battery separator with improved safety and bonding properties compared to existing separators. The separator has a porous substrate coated with a thermally responsive layer containing melting point tunable temperature-sensitive polymer microspheres. At normal operating temperatures, the microspheres do not melt. But at abnormal temperatures, like during overcharge or short circuit, the microspheres melt and seal the separator pores preventing internal shorts. This avoids thermal runaway. The melting temperature tuning allows sealing at lower temperatures than pure polymer layers. The microspheres also improve cold pressing bonding strength between the separator and electrodes.

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Separator for lithium-ion batteries with fire suppression capability to prevent battery cell thermal runaway and propagation. The separator has a microporous layer sandwiched between the electrodes, with fire suppression layers on one or both sides. The fire suppression layers contain a ceramic with interconnected pores filled with a cyclophosphazene compound. The cyclophosphazene quenches and inhibits combustion chain reactions when exposed to high temperatures, preventing thermal runaway propagation in case of battery cell failures.

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Battery separator and secondary battery with improved safety and heat resistance. The separator contains temperature sensitive microspheres that melt and seal the pores at lower temperatures compared to the main separator layers. This prevents internal short circuits at lower temperatures where the main layers haven't fully melted. The microspheres also improve heat resistance by melting and sealing the pores at higher temperatures. This reduces the risk of thermal runaway. The microspheres can be made of materials like polyoxides, polyethylene, polyvinylidene fluoride, ethylene-vinyl acetate copolymers.

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A secondary battery design to improve heat safety and prevent thermal runaway. The battery has a separator between the positive and negative electrodes with a width ratio w where w(width of separator) > width(anode active material) > width(cathode active material). This prevents shrinkage of the separator at high temps from shorting the electrodes. The positive electrode has a ceramic coating close to the tab. The ceramic coating adhesion to the separator (a) is greater than adhesion to the film (c) while the separator adhesion (b) is greater than the ceramic adhesion (d) to the current collector. This balance prevents competitive forces between the separator and film.

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Coating for batteries that improves heat resistance and prevents short circuits. The coating contains negative thermal expansion materials and/or zero thermal expansion materials, like ZrW2O8, HfW2O8, ZrMo2O8, AM2O7 (A=Th, Zr, Hf, Sn, M=P, V), along with ceramic materials and a binder. The coating is applied between the electrodes and separator to prevent fusing, piercing, and short circuits during battery operation. The negative/zero thermal expansion materials expand less than the electrodes or separator during heating, reducing thermal stress and shrinkage. The ceramic materials provide heat resistance. The binder binds the coating to the electrodes/separator.

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Diaphragm for lithium ion batteries with improved thermal stability to prevent short circuiting and explosions at high temperatures. The diaphragm has a base film coated with two ceramic layers. The first layer near the film has spherical ceramic particles with a high melting point additive (>200°C). The second layer farther from the film has flaky ceramic particles with a lower melting point additive (100-135°C). The roughness of the second layer's surface in contact with the first layer is 30-900nm. This two-stage ceramic coating provides better thermal stability compared to single-layer coatings, reducing the risk of short circuiting and explosion at high temperatures.

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Battery separator for high voltage lithium-ion batteries that can operate at 5 volts or higher without degradation. The separator is a microporous membrane with improved oxidation resistance for use in high voltage lithium batteries. It contains a novel polymer, embedded ceramic particles, and ceramic coatings to stabilize the separator at high voltages. The specific compositions and structures allow the separator to function in high energy, high voltage lithium batteries without oxidation issues or trickle charging.

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Battery separator with improved safety and quick charge capability for lithium-ion batteries. The separator has three layers: a ceramic layer, a heat-resistant polymer layer, and a glue layer. The ceramic layer contains microspheres with melting points between 90-130°C that close the separator before thermal runaway. The heat-resistant polymer prevents separator shrinking and breaking at high temperatures. The separator composition and design enables safe high-temperature sealing and prevents internal short circuits. Matching this separator with graphite anodes further improves charge times.

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A heat-resistant battery separator with improved integrity and shutdown capability for lithium-ion batteries. The separator has three layers: two microporous layers sandwiched between a heat-resistant layer. This configuration provides separation and integrity at high temperatures during thermal runaway. The heat-resistant layer can be made of a high melt integrity material like polyaramid, polyimide, or polyamideimide. The microporous layers can have functional groups on their surfaces that increase adhesion to the heat-resistant layer. This prevents curling and delamination during thermal runaway.

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A lithium ion battery design to improve overcharge resistance by using a porous film between the positive and negative electrodes. The porous film has an insulating ceramic containing Fe or Ni particles attached to the electrode or separator surfaces. The roughness of the ceramic particles increases their surface area and adhesion to the binder, preventing collapse of the porous film during battery shutdown. This maintains insulation between the electrodes during overcharge events and reduces temperature spikes compared to a smoother ceramic.

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Diaphragm for lithium-ion batteries that improves needling safety and prevents thermal runaway without affecting battery performance. The diaphragm is made by coating a thin layer of a high-temperature resistant polymer like polyimide on one side of the separator. This layer melts and seals the cell when punctured during needle penetration testing, preventing internal short circuits and thermal runaway. The coated separator provides high needling safety while maintaining normal battery operation.

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Integrated preparation method for lithium battery diaphragms and batteries that improves battery safety without sacrificing capacity. The method involves coating a heat-stable material on the base film of the battery separator during diaphragm preparation. This coating provides improved thermal stability compared to the base film alone. The coated separator is then used to assemble the battery. This integrated preparation enables a single-step process to enhance battery safety without adding extra steps or materials. The heat-stable coating prevents separator contraction or fusion during high-temperature conditions, reducing internal short circuits and improving battery safety.

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A separator for lithium-ion batteries that improves thermal management during charging and discharging cycles. The separator has an electrically insulating, porous support material containing an electrically insulating but thermally conductive ceramic filler. The filler is selected from carbides, nitrides, borides, or mixtures thereof. This allows the separator to conduct heat between the electrodes, preventing internal hotspots and improving thermal distribution compared to traditional separators. The coated separator is used in lithium-ion cells to reduce temperature gradients and improve heat dissipation during charging and discharging.

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Ceramic separator for lithium-ion batteries with improved performance and safety compared to conventional separators. The ceramic separator has a diaphragm with ceramic coatings on specific areas. The functional area contacting the electrodes has larger porosity ceramic coatings for ion conduction and electrode isolation. The overhang areas extending beyond the electrodes have smaller porosity ceramic coatings for better thermal stability and shrinkage resistance. This provides optimized separator properties for each region to balance electrochemical performance and safety.

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Low temperature shutdown ceramic separator for lithium batteries that prevents battery failures at low temperatures. The separator has a polymer porous base film coated with PEO and alumina layers. The PEO layer helps the ceramic seal at lower temperatures compared to ceramic alone. This allows the separator to close before violent battery reactions occur, preventing further cell damage. The coated separator improves safety by preventing battery runaway at lower temperatures.

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Lithium battery diaphragm with improved safety by preventing thermal runaway and explosions. The diaphragm has a coated separator film with multiple layers to dissipate localized heat. The layers are: 1) a ceramic coating on the base film to prevent shrinking, 2) a first heat-conducting coating on the ceramic surface, and 3) a second heat-conducting coating on the first coating. When a local hotspot occurs inside the battery, the first and second heat-conducting coatings rapidly conduct heat to the battery ends and case, preventing accumulation and mitigating risk of fire or explosion.

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Separator for lithium-ion batteries with improved heat resistance to enable high energy density and capacity lithium-ion batteries used in applications like electric vehicles. The separator has a heat-resistant layer containing inorganic oxide particles with a high heat absorption capacity. This layer prevents ignition during short circuits and thermal runaway. It also has a coating on the oxide particles to prevent side reactions with the electrolyte. The coating has a melting point above 120°C to avoid fusing with the oxide particles. The separator has a standard separator substrate with the heat-resistant layer added.

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Multilayer film for thermal stability and puncture resistance in lithium-ion battery separators. The film has a diaphragm body with ceramic coatings on each side. Non-woven fabric layers are attached to the ceramic coatings. The ceramic coatings are spaced strip shapes with staggered placement. This configuration improves thermal stability and prevents short circuits by reducing shrinking and piercing compared to traditional polymer separators.

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A lithium-ion battery separator with improved thermal resistance for preventing overheating and improving safety. The separator has a thin film made of heat-resistant material, a thin heat-conducting ceramic coating, and a thin thermally fuse layer. The film prevents electrode material diffusion, the coating disperses heat, and the fuse seals micropores to prevent electrolyte leakage if overheating occurs. The thinness of the layers balances thermal performance with battery energy density.

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Lithium-ion battery with improved safety during overcharge. The battery has a separator with a meltable polymer layer coated on one side. When overcharged, the polymer melts and forms a barrier on the cathode surface to prevent short circuiting and thermal runaway. The polymer melting temperature is optimized to match the battery's overcharge conditions. The separator is arranged with the polymer layer facing the cathode. This allows the polymer to prevent thermal runaway if the battery overcharges by melting and forming a barrier on the cathode surface. The polymer layer can also contain inorganic materials for better performance.

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