Maintaining Consistent Performance of EV Batteries

Lithium-ion battery electrodes with a unique non-uniform porous structure that enhances performance compared to conventional electrodes. The positive electrode is made by setting the porosity of the surface layer higher with larger active material particles compared to the inner layer. This non-uniform structure improves battery rate performance and capacity retention by reducing resistance and impedance.

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Controllable lithium-ion battery design with long cycle life by precise pre-lithiation of the negative electrode. The battery includes a standard cell with positive and negative electrodes, separators, etc., and adds an independent lithium replenishing electrode or a metal lithium layer on the negative electrode. The lithium layer supplies excess lithium ions to compensate for cycle-induced lithium loss. The lithium replenishing amount is precisely controlled to optimize battery life without excessive over-lithiation.

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Enhanced lithium secondary batteries with improved capacity, cycle life and output. The batteries use positive and negative electrodes with specific properties, and a nonaqueous electrolyte containing a specific compound. The positive electrode has a conductive material content of 6-20% by mass, a density of 1.7-3.5 g/cm3, and an active material layer thickness to current collector thickness ratio of 1.6-20. The negative electrode has an average primary particle diameter of 0.1-2 μm and a tap density of 1.3-2.7 g/cm3.

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Battery pack with improved low-temperature endurance by optimizing discharge voltage plateaus of different cells. The battery pack has an outer area, middle area, and inner area inside the pack. Cells with dual voltage plateaus are arranged with lower plateau bias towards the colder outer area and higher plateau bias towards the warmer inner area. This balances discharge capacities at low temperatures.

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Battery pack structure for electric vehicles that improves temperature uniformity and heating control with a heating plate enclosed in a heating unit. The battery pack has a heating plate that surrounds the battery cells and a separate heating unit that encloses the heating plate. This provides better temperature uniformity and heating compared to directly attaching heaters to individual cells. A control unit monitors the battery temperature and operates the heating unit as needed.

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Secondary battery system with connected battery modules that each have a heating device. The system controller determines the power supplied to each module's heater so that modules with higher SOC or charge receive more heating power. This balances the charge levels between modules by consuming excess energy from higher charged modules. The controller also activates heating based on temperature, SOC, or charge levels. This reduces SOC and charge imbalances between modules while minimizing wasteful power consumption. The system can be used in electric vehicles to maintain module performance and longevity.

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Battery heating system for electric vehicles to improve battery performance in cold temperatures without impacting state of charge. The system uses a bidirectional DC-DC converter and auxiliary energy storage device connected to the vehicle battery. The converter alternates the current direction through the battery at a controlled frequency. This generates internal resistance and heating. The state of charge remains constant since current flows in and out. The frequency can be optimized based on battery temperature and age.

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Aging lithium-ion battery electrolytes before cell assembly to increase cycle life and stability. The aging process involves allowing the electrolyte to sit for several days at room temperature before using it in batteries. This aging step allows the electrolyte additives to partially decompose and transform into more effective species that protect the electrodes and stabilize the electrolyte during cycling.

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Microporous polymer separator with improved shutdown properties for lithium ion batteries. The separator has a microporous polyolefin membrane coated with a thin, uniform layer of inorganic particles to enhance heat resistance and prevent internal short circuits. The separator resists shrinking, tearing, and pinhole formation above the melting point of the base polymer, which can cause electrode exposure and shorts. The coated separator maintains shutdown properties and dimensional stability at high temperatures.

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Battery module design for improved EV battery performance and safety while reducing swelling and failure rates. The module has an elastic bead unit between the battery cells and the cover plate that applies a controlled amount of pressure to the cells. This improves performance and enables better swelling control compared to conventional modules. The module design can be used in battery packs that are used in electric vehicles.

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Battery electrode plates for improved EV battery performance. The electrode plates have a composite current collector with a thin conductive layer sandwiched between a support layer and, optionally, protective layers. This reduces weight and increases energy density compared to metal foil collectors. A conductive primer layer containing one- or two-dimensional conductive materials like nanotubes or graphene is used to connect the thin conductive layer to the electrode active material, improving conductivity.

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Battery temperature adjustment system for electric vehicles to prevent battery deterioration. The system has a battery, cooling device and control system. When the vehicle is connected to an external power source, the control system selects either the battery or external power to cool the battery based on a deterioration sensitivity map. If cooling with external power would cause more deterioration than using battery power, it cools with battery power.

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Lithium complex oxide for lithium-ion batteries that exhibits improved capacity, resistance, and lifetime. The lithium complex oxide is prepared in a way that modifies the surface of primary particles in the oxide particles. The primary particles on the outer surface of the oxide particles are coated with cobalt. This creates a graded concentration of cobalt from the coating towards the center of the primary particle. The cobalt coating alters the crystalline structure of these particles compared to the interior particles and also reduces residual lithium after washing. This improves lithium ion pathways, battery efficiency, and high temperature stability.

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Electrode layer for all-solid state batteries that improves capacity retention. The electrode layer contains an electrode active material, a sulfide solid electrolyte, and a residual liquid. The residual liquid has a low cohesion energy density (delta P < 2.9 MPa½) and a high boiling point (190°C or higher). This reduces cracking and deterioration of the sulfide electrolyte while maintaining ionic conductivity.

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Non-aqueous electrolyte solution for energy storage devices like batteries and capacitors that can improve performance at high temperatures and voltages while inhibiting unwanted gas generation. The electrolyte contains a carboxylic acid ester compound, like ethyl lactate, that forms a protective film on the electrodes to enhance stability and prevent decomposition. This improves storage characteristics and capacity retention at high temps/voltages.

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A battery pack design to improve discharge performance at low temperatures by better managing temperature differences across the pack. The pack has two types of battery cells with different internal resistances. Cells with lower resistances are placed in outer pack areas with better heat dissipation. Cells with higher resistances are placed in inner pack areas with poorer heat dissipation. This balances temperature effects across the pack to mitigate reduced performance due to cold temperatures.

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A bridging device to bypass failed cells in a battery pack to improve overall reliability and prevent complete pack failure. The device uses a bridging switch that connects two current conductors in parallel with a cell. When the cell temperature exceeds a threshold, the switch closes to create a low resistance path between the conductors. This causes current to flow, heating the conductors and melting a bridging material on them. The molten material bridges the gap between conductors, permanently bypassing the cell.

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Increasing the performance and durability of solid-state lithium-ion batteries through optimized electrode and electrolyte interfaces. Applying a lithiated ionomer electrolyte directly to the electrode layer to form an optimized electrode-electrolyte composite. This improves battery performance and stability over existing solid-state batteries by overcoming issues like limited cathode loading and solid electrolyte conductivity. The specific process involves using a lithiated ionomer electrolyte applied to a cathode layer to form an optimized electrode-electrolyte composite.

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A lead-acid battery with a separator design that reduces acid stratification without sacrificing battery performance. The separator is an envelope type that surrounds the battery plates, but with apertures along the sealed edges to allow electrolyte circulation. This provides the benefits of enveloping plates to prevent shedding and mossing shorts, while also preventing acid stratification through the apertures.

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Fuel cell power generator with a controller to optimize pressure and flow rates to maximize efficiency and performance. The fuel cell has separate hydrogen and air loops with a blower in each. The controller monitors loop pressures and adjusts blower speeds to maintain optimal conditions. It also adjusts blower speeds based on power demand to prevent over/under pressurization.

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