Lithium Iron Phosphate in EV Battery Systems

Lithium iron phosphate (LFP) cathode material for lithium-ion batteries with improved rate performance and cycle life. The LFP has a lattice distortion of 0.058-0.08% to reduce lithium ion transfer resistance. The LFP can be prepared by co-doping elements like Na, K, Mg, Ti, V, W, Nb, La, Cr, Mo, Ca, Zn into the Fe and Li sites. The co-doping expands the lattice, increases diffusion coefficients, and suppresses crystal growth. The co-doped LFP has specific surface areas of 7-13 m2/g, median particle sizes of 0.5-2.5 µm, and carbon content of 0-5 wt%. The co-doping and particle size optimizations improve LFP electrochemical properties like

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Coating a low-temperature rate type lithium iron phosphate cathode material with a thin film of yttrium titanium oxide (YTO) to improve low-temperature and rate performance. The coating process involves sol-gel synthesis of a mixed metal hydroxide precursor, followed by high-temperature sintering in air to form a uniform YTO film on the lithium iron phosphate surface. This coating reduces the lithium diffusion barrier and accelerates lithium ion transport, significantly improving low-temperature and rate characteristics compared to uncoated lithium iron phosphate.

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Battery management system to balance input/output characteristics between different types of assembled batteries like LFP and ternary batteries. The balancing is done by temperature regulation when the overall system temperature is below a reference. The regulation involves raising the temperature of LFP batteries more than ternary batteries using techniques like higher charging/discharging power, larger temperature rising ripple current, and heating. Above the reference temperature, charging/discharging power is increased for ternary batteries to match LFP. This balances calorific values and deterioration rates between battery types.

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Lithium iron phosphate (LFP) cathode material for lithium-ion batteries with improved properties like higher capacity, rate performance, and reduced moisture absorption compared to conventional LFP. The improvements come from synthesis methods using precursors like vanadium phosphate and iron phosphate with specific molar ratios, dopant levels, and particle pore structures. The synthesis reduces emissions and eliminates ammonia compared to conventional LFP production. This leads to LFP powders with optimized physical properties like smaller pore sizes and lower moisture absorption, which translate to better battery performance.

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Lithium iron phosphate (LiFePO4) cathode material for lithium-ion batteries with improved ionic conductivity and higher energy density compared to undoped LiFePO4. The cathode material has a granularity of D50 greater than or equal to 1 um. The improved ionic conductivity is achieved by adding secondary phosphate phases (LiMxPyp) near the surface of the core LiFePO4 phase. The secondary phase dopants contain transition metals or main group elements like Mn, Co, Gd, In, V, Zr, etc. The doped LiFePO4 cathode material has higher ionic conductivity and can be prepared using a precipitation process to control particle size. This allows higher loadings and bulk density compared to nanoscale LiFePO4.

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High energy density fast charging lithium iron phosphate battery with improved capacity and cycle life compared to conventional lithium iron phosphate batteries. The battery has a composite lithium iron phosphate positive electrode with lithium supplementary materials, and a negative electrode with fast charging graphite and silicon. The compositions and particle sizes of the positive and negative electrodes are optimized to increase capacity, reduce density, and improve fast charging. This allows the battery to have energy density of 200-220 Wh/kg, similar to ternary batteries, while meeting the needs of passenger vehicle fast charging and cycle life.

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Intelligent lithium battery control system that improves performance, reliability, and safety of lithium battery packs used in electric vehicles, drones, and energy storage systems. The system monitors battery status, optimizes charge/discharge strategies, predicts battery health, manages power peaks, balances energy use, provides remote monitoring, and implements short circuit protection. Algorithmic optimization, temperature management, and data analysis enhance battery performance and longevity.

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A cooling system for a battery management module used in lithium iron phosphate (LiFePO4) batteries to prevent overheating and component failure during long-term operation. The cooling system has a housing with a fan, fins, heat spreading plate, and spring-loaded clips to attach to the battery pack. The fan blows air through the fins to cool the internal electronics, and the heat spreading plate transfers heat from the components to the fins. The spring-loaded clips attach the module to the battery pack to provide mechanical stability and electrical connection. This active cooling system allows the battery management module to operate at higher power levels and longer durations without overheating components.

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Flaky lithium iron phosphate (LFP) with improved properties for batteries, and a method to synthesize it. The flaky LFP has a composition of LiFe0.3Mn0.7P04. The synthesis involves dissolving iron, manganese, and phosphorus sources in a low temperature solution, adding lithium source, adjusting pH, and hydrothermally reacting at low temperature to produce flaky LFP. The key features are using a specific ratio of iron to phosphorus, low temperature synthesis, and adjusting pH. This results in flaky LFP instead of the usual lumpy or spherical shape. The flaky LFP has higher lithium content, lower impurity content, and better cycling performance compared to conventional LFP.

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Control system and method for lithium iron phosphate battery packs used in electric motorcycles that provides improved temperature management, charge/discharge control, and overall battery health for longer life. The system has a compact layout with staggered cell arrangement in the pack to improve space utilization and heat dissipation. The control module monitors pack status, compensates for temperature, and intelligently charges/discharges to optimize battery performance.

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Lithium iron phosphate battery with improved low temperature and high rate performance for applications like vehicle starting. The battery uses a modified electrode composition and assembly method to enhance performance. It involves adding small amounts of silicon and graphite blended with oxide coating to the negative electrode, carbon coating on the positive electrode, and a porous ceramic diaphragm. This composition and assembly improves low temperature and rate performance compared to conventional lithium iron phosphate batteries.

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Preparation method for high conductivity and high density lithium iron phosphate (LiFePO4) cathode material for lithium-ion batteries. The method involves doping the iron phosphate precursor with titanium oxide during synthesis. This doping step improves the LiFePO4's electrical conductivity and compaction density. The doped iron phosphate precursor is then roasted and crushed to form the final LiFePO4 cathode material.

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Lithium iron phosphate (LiFePO4) batteries with integrated temperature control to enable operation in extreme hot and cold environments. The batteries have a battery management system (BMS) that monitors and controls heating and cooling elements inside the battery. These elements include phase change materials (PCMs), heat exchangers, fans, thermal electric devices, and coolers. The BMS activates the appropriate elements to maintain optimal battery temperature within a range of 5-40°C for uninterrupted operation in extreme temperatures. This prevents damage, decreased life, and performance degradation.

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Reducing internal current circulating between battery packs in multi-battery electric vehicles to prevent issues like lithium plating. It involves actively managing the circulating current to keep it below a limit. Techniques include feeding a preload current into the bus to balance it, selectively disconnecting weakest packs, and reducing load on high-capacity packs. This prevents imbalances that can cause plating.

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Low-temperature charge and discharge management method for iron-lithium batteries that enables charging and discharging at sub-zero temperatures without external heating devices. The method involves limiting charge and discharge currents and voltages based on initial temperature. When initial temperature is below a threshold, charging is prohibited unless the current is above the threshold. This prevents deep discharge at low temperatures. If charging is allowed, the voltage limit is set lower. During charging or discharging, if temperature rises above a threshold, the limit is relaxed. This prevents overheating.

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Hybrid battery management system for reducing cost of high-performance lithium titanate batteries by pairing them with lower-cost lithium iron phosphate batteries. The system uses a master control unit, lithium titanate slave control unit, lithium iron phosphate slave control unit, charging/discharging interface, and heating unit. The master unit coordinates charging/discharging of both battery types. The lithium titanate slave handles its own battery, while the lithium iron phosphate slave is managed by the master. This allows leveraging the advantages of both battery chemistries, like high cycle life/rate for lithium titanate and low cost/energy density for lithium iron phosphate, in a single hybrid battery pack.

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An operation and maintenance method for lithium iron phosphate batteries in electric vehicles that improves battery performance and extends life cycle. The method involves charging the battery using a three-stage process: constant power, constant current, and constant voltage. This is followed by discharging at constant power. This charging sequence helps balance cells, prevent polarization, and enable high-rate discharge. After discharge, the battery is cycled through charge-discharge steps.

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High energy density lithium iron phosphate (LFP) battery with improved cell design and manufacturing method to increase cell and pack energy density beyond 180Wh/kg. The cell design uses optimized electrode coatings with specific areal densities and compaction densities. The manufacturing method involves compressing the electrode coatings to higher densities, reducing electrolyte volume, and using thinner separators with ceramic coatings. These modifications allow higher energy density LFP cells and packs without sacrificing safety.

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Lithium secondary battery with improved power characteristics by using a specific combination of positive and negative electrode materials. The battery has a positive electrode with lithium iron phosphate (LFP) and layered lithium nickel manganese oxide (NMC) as the active material. The negative electrode has a negative electrode active material with a potential difference of 3.10V or more from LFP at 50% state of charge. This configuration allows higher power output in the discharge end region compared to traditional LFP-only batteries.

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Optimizing the performance, life, and cost of batteries in electric vehicles by controlling their operating modes. The battery management system monitors cell voltage, temperature, and state of charge. In certain conditions like charging with partial state of charge or hot ambient temperatures, it suspends charging or reduces charge rate. During driving, it maintains a higher temperature. This prevents excessive charge depths, voltage spikes, and thermal stress that degrade battery health. By dynamically adjusting operating conditions, it balances performance, longevity, and cost.

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