Browse Topic: Lead-acid batteries
This paper carried out the fire failure analysis of valve-regulated lead-acid battery in communication equipment room. Through disassembly and observation of the battery and iron frame of battery cabinet in the area of fire origin, we obtained the key residual traces and used the physical and chemical analysis methods such as macroscopic/microscopic morphology, EDS, X-ray and metallographic, it was finally judged that the leakage of the battery electrolyte lead to the connection of the battery electrode plate and the iron frame and subsequently the electric heating fault caused the fire accident. Furthermore, we put forward some suggestions according to the existing problems, which may contribute to the prevention of similar failures.
Due to the expense and time commitment associated with extensive product testing, vehicle manufacturers are developing new simulation techniques to verify vehicle component performance with less testing and more confidence in the final product. Battery lifetime is of particular difficulty to predict, since each battery is different and there are many different control scenarios that could be implemented based on the specific requirements of each battery type. In order to solve this problem for a 12V auxiliary lead-acid battery, a battery durability analysis model has been previously adapted from lithium-ion applications, which is capable of verifying the impact of lead-acid battery durability in a short period of time. In this study, calibration tools for this model were developed and are presented here, and durability analysis and verification are performed for the application of new electric vehicles. New control strategies, designed specifically for the auxiliary batteries in electric vehicles, were evaluated and the durability guide standard (current specification within 6%) was met. The current simulation tools are set up based on battery unit tests, and coefficients are adjusted to account for the impact of measurement procedures on measurements in a full, end-to-end, battery lifetime simulation process that takes an engineer from raw data all the way through final lifetime prediction. The tools are built to simulate expected battery life under different environmental and charge control scenarios. EV drive cycles were run to determine whether or not flooded (FLD) or absorbed glass mat (AGM) batteries were more appropriate for the application studied here, and whether each battery type would be able to meet warranty requirements. Results show that an AGM battery would not fail in a 5 year usage interval, and that a FLD battery would not meet the minimum 3 year requirement for the control scenarios used.
The 1915 Detroit Electric Brougham was powered by lead-acid batteries, and so was the first generation of the General Motors EV1 back in 1996. The 1915 car could reportedly travel 80 miles (129 km) on a single charge, and the EV1 wasn’t much better, with a range of 70 to 100 miles (113 to 161 km).
Most industry experts cite GM's EV1 as the first EV of contemporary times. But the EV1 had a pioneering forerunner from decades prior. The production EV1 by General Motors in the 1990's gets some credit for being, technology-wise, one of the first viable EVs. The limitation was its heavy lead-acid battery storage and short range. Less known is the fact that in 1963, a full quarter century earlier, GM was working on its first EV that pioneered a state-of-the-art propulsion system that is still the basis for all EVs today.
This method covers electric outboards that are rated in terms of static thrust.
Light Electric Vehicles (LEVs) such as golf carts have been traditionally powered by lead-acid batteries. Original Equipment Manufacturers (OEMs) are transitioning to Lithium-ion (Li-ion) batteries as they offer several advantages over lead-acid batteries, such as higher power density, longer run time, and zero maintenance. However, a successful transition requires careful consideration of the differences in the cell chemistry and the battery pack behavior.
Lithium-ion batteries (LIBs) have become a focus of research interest for electric vehicles (EVs) due to their high volumetric and gravimetric energy storage capability, lower self-discharge rate, and excellent rechargeability coupled with high operational voltage as compared with the lead-acid batteries. This paper presents different machine learning approaches to predict health indicators & usable cycle life of LIBs. Here, we focus on two important battery health indicators i.e., battery discharge capacity and Internal resistance (IR). We used publicly available multi-cycled data of the Lithium Iron Phosphate (LFP), Lithium-Nickel-Manganese-Cobalt-Oxide (NMC) and Lithium Cobalt Oxide (LCO) cells. The approach proposed for predicting health indicators involves using a time-series model in the areas where the actual data i.e., from the Beginning of life (BOL) to the End of life (EOL) is not available. This methodology includes dynamically training a time-series based regression models with the last 100 cycles of information. It includes formulating the equations for individual C-Rates with discharge capacity, and internal resistance of the last ‘T’ cycles as an input to estimate the future discharge capacity and internal resistance after ‘X’ cycles. The accurate results for predicting battery health indicators have been achieved using the concept of dynamic training and timeseries model. This approach helps for quick estimation of battery State of Health (SOH). In the second approach, we have suggested a method for useful cycle life estimation using early cycle data. Here, we extracted battery voltage, current and temperature values of initial 100 cycles for training the model. This method has helped us achieve a minimum RMSE of 8.9 %, showcasing a noteworthy accuracy.
As a mechanical engineering student at Carnegie Melon, Thomas Healy wondered why passenger cars were moving toward electrification, but commercial trucks were not. That curiosity has led to one of the greenest, most innovative, trucking concepts on the planet. “I learned that there had been some electric trucks made, but at that point they were built on lead acid batteries and outdated technology by today’s standards,” he said.
This paper details the design and components of a high-power density Hybrid-Electric Power generation testbed that is being built by the Eagle Flight Research Center at Embry-Riddle Aeronautical University, Florida. The system consists of a twin-rotor rotary Wankel engine, a radial flux Permanent Magnet Synchronous Machine used as the generator along with its inverter/controller, a 400 V Lead-acid battery pack, a vehicle control unit, and the associated thermal systems. The system weighs 324 lbs. (147 kg) before fuel and is estimated to achieve peak power of 134 hp (100 kW) with the High-Voltage battery and sustained power of 70 hp (52 kW) with just the hybrid-electric system. With 8 gallons of fuel, the system is estimated to realize a specific energy of 0.37 hp-h/lb. (0.61 kWh/kg), and a specific power of 0.46 hp/lb. (0.76 kW/kg). The system control was implemented on the Vehicle Control Unit using a feedforward-feedback control loop with user-defined speed and output power values.
An uninterruptible power supply (UPS) is a great way to ensure that power to important loads is not lost in the case of a power failure. When incoming power to the UPS is lost, it immediately switches into battery mode, which allows the connected loads to run off this reserve energy. But if the UPS itself fails, then any power loss will shut down the entire system. Therefore, it is important to make sure a UPS is reliable and reaches its full lifetime potential. Using the proper battery for each application and constantly monitoring the system to maximize uptime can ensure the full life of a UPS.
This document contains definitions currently used in the automotive industry as they relate to energy storage and batteries for starting, lighting, and ignition applications, as well as for hybrid electric vehicles (HEV) and electric vehicles (EVs). It is intended that this document be a resource for those writing other battery, HEV, and EV documents, specifications, standards, or recommended practices. The use of the term “battery” in this document can be assumed to be a rechargeable battery (secondary battery). The terminology may be applied to other industries if desired.
Lead-acid batteries have been widely used in automotive applications. Extending battery life and reducing battery warranty requires reducing any deteriorating to battery internals and battery electrolyte. At the end of battery life, it is required to maintain at least 50% of its initial capacity [1,2]. The rate of battery degradation increases at high battery temperatures due to increased rate of electrochemical reactions and potential loss of battery electrolyte. For Lead-Acid batteries, an electrolyte solution consists of diluted sulfuric acid. Battery electrolyte/water loss affects battery performance. Water loss is caused by high internal battery temperature and gassing off due to battery electrochemistry. High temperatures, high charging rates, and over charging can cause a loss of electrolyte in non-sealed batteries. In sealed batteries, the same factors will cause an increase in temperature and pressure which can eventually result in the release of hydrogen and oxygen gases. Any loss of electrolyte resulting in part of the plates being above the electrolyte surface will result in reduced battery performance. In this paper we present an approach for design of battery thermal protection and selection of charging voltage ranges in order to reduce electrolyte (water) loss and reduce the effects of thermal degradation. Experimental bench test data were gathered at various voltages and at various battery temperatures. A mathematical model was developed to correlate water loss to the battery voltage and temperature. In order to reduce effect of external heating of the battery, thermal simulation tools are applied to assist in selecting the optimum heat shield design. The selected design along with the developed correlations are used in a vehicle level transient thermal analysis model to predict water loss and battery temperature throughout the battery life. Thus a robust approach can be followed for an improved battery thermal management and an improved battery service life and performance.
The paper presents a trend of vehicles connected to the internet, adding connected features related to the customers and its impact inside vehicle lead-acid battery health. Lead acid battery work in internal combustion engine context as the power source to crank vehicle and allow usage of vehicle electrical features with engine off, as example: use the infotainment system with engine off. It’s not rare to observe field issues, characterized as dead battery, that customer cannot crank the vehicle, causing dissatisfaction, few cases caused by some loads kept on with engine off. This paper intent to navigate through 3 macro phases and a conclusion: First phase shows concept of battery State of Charge (SOC), define a management of key-off load (KOL) current consumption and explain battery drain calculation with main objective to align key background knowledge to understand next phases; Second phase focus on modeling a hypothetic not connected vehicle in regarding of battery design including battery size definition, expected battery performance versus vehicle KOL and baseline KOL. Third phase evaluates the growing curve of connected features versus battery demand, making few possible scenarios comparison of battery performance impact through connected features deployment in the vehicle. The summary of expected impact completes the conclusion in this paper forecasting a battery deterioration caused by connected features. Also, it’s included few potential next steps to mitigate impacts.
This paper deals with the concept design of a mini tractor which is suitable for mild ploughing operations with 5 kW electric motor. The low cost battery driven mini tractor operates on a lead acid batteries. The design principles and calculations of electric tractor powertrain are studied and delineated in details. By using these calculations, parameters of the major powertrain components like drive motor, battery and transmission are obtained. The powertrain model of an electric tractor is modelled with MATLAB/Simulink to estimate the traction and battery performance. The CAD model of tractor is prepared in Solidworks and CAE analysis of chassis is performed using ANSYS Workbench to ensure safety and reliability. Calculations are performed for tractor subsystems such as steering system and braking system. The analysis results confer the design as safe and satisfactory in terms of performance.
This SAE Recommended Practice provides for common test and verification methods to determine lead acid and nickel metal hydride electric vehicle battery module performance. The document creates the necessary performance tests to determine (a) what the basic performance of EV battery modules is, and (b) if battery modules meet minimum performance specification established by vehicle manufacturers or other purchasers. Specific values for these minimum performance specifications are not a part of this document.
The battery is a central part of the vehicle’s electrical system and has to undergo cycling in a wide variety of conditions while providing an acceptable service life. Within a typical distribution chain, automotive lead-acid batteries can sit in storage for months before delivery to the consumer. During storage, batteries are subjected to a wide variety of temperature profiles depending on facility-specific characteristics. Additionally, batteries typically do not receive any type of maintenance charge before delivery. Effects of storage time, temperature, and maintenance charging are explored. Flooded lead-acid batteries were examined immediately after storage and after installation in vehicles subjected to normal drive patterns. While phase composition is a major consideration, additional differences in positive active material (PAM) were observed with respect to storage parameters. Batteries stored in a hot environment and kept at constant float voltage for a significant duration exhibited favorable PAM characteristics relative to other storage environments. In all cases, batteries kept on float charge throughout storage exhibited favorable PAM characteristics relative to batteries stored under equivalent conditions on open-circuit charge.
ABSTRACT Saft has continued to develop lithium-ion replacement batteries for the traditional lead-acid batteries for use in military vehicles. Saft’s 24 volt Xcelion 6T® delivers power at high rate that surpasses the delivered capacity of two lead-acid batteries. The battery design is tailored to support high rates, even at extreme cold temperatures, to support the mission needs for silent watch and starting for military vehicles. An additional design variant is now available, the Xcelion 6T Energy, to provide 30% more energy while still delivering excellent cranking capability. Both products are industrialized and in use in large new vehicle programs. Additionally, development continues on a MIL-PRF-32565 compliant version with release to market expected in 2019.
The use of Hybrid Electric Vehicles (HEV) will become imperative to meet the emission challenges. HEV have two power sources-fossil fuels driven I.C. Engine and the battery based drive. Battery technologies have seen a tremendous development, and therefore HEV’s have been benefited. Even as the battery capacities have improved, maintaining and monitoring their health has been a challenge. This research paper uses open-source platform to build a BMS. The flexibility in the implementation of the system has helped in the rapid prototyping of the system. The BMS system was evaluated on a scaled-down electric toy car for its performance and sustainability. The BMS was evaluated for reverse polarity, protection against overcharge, short-circuit, deep discharge and overload on lead acid battery. It also includes temperature monitoring of the batteries. This proposed system is evaluated on the in-house HEV two-wheeler. The initial results are promising. A dedicated android smartphone application is developed for BMS which continuously monitors battery voltage, current, battery temperature, battery state of charge (SOC) and battery health. The system measures current, voltage and temperature accurately up to 1.5%, 1% and ±0.5 °C respectively. The result of state of charge given by BMS at particular voltage is in agreement with the standards of Battery Council International with maximum error of 0.5%.
The 12 V advanced start stop systems can offer 5-8% fuel economy improvement over a conventional vehicle. Although the fuel economy is not as high as those of mild to full hybrids, its low implementation cost makes it an attractive electrification solutions for vehicles. As a result, the 12 V advanced start stop technology has been evolving fast in recent years. On one hand, battery suppliers are offering a variety of energy storage solutions such as stand-alone lead acid, stand-alone LFP/Graphite, dual batteries of lead acid parallel with NMC/LTO, LMO/LTO, NMC/Graphite, and capacitors, etc. For dual battery solutions, the architecture also varies from passive parallel connection to active switching. On the other hand, OEM are considering to leverage a lot more use out of traditional 12 V SLI (start, light, and ignition) for functions such as power steering, air conditioning, heater, etc. Depending on battery architecture and vehicle functioning design, the energy management strategy can easily become complicated. Since many variables are involved in the design of 12 V advanced start stop systems, an integrated simulation tool with a couple of modularized models including vehicle, batteries, and performance characterization have been developed. The modularized tool would help to evaluate many aspects of the design from motor size selection, power network management, battery evaluation, testing standardization. As a specific demonstration, in this work, we use the tool to compare three chemistries: stand-alone AGM, stand-alone LFP, and dual batteries of lead acid and LTO for different driving cycles including NEDC, WLTP, FTP72, and HWFET as function of motor size.
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