Naslov
Battery Packs in Electric Vehicles

Autori
Peršić, Antonio

Vrsta, podvrsta i kategorija rada
Poglavlja u knjigama, znanstveni

Knjiga
Wind and Solar Energy Applications: Technological Challenges and Advances

Urednik/ci
Satish Kumar Peddapelli, Peter Virtic

Izdavač
CRC Press

Grad
Boca Raton (FL)

Godina
2023

Raspon stranica
1-366

ISBN
9781003321897

Ključne riječi
Battery Pack

Sažetak
It is a known fact that if all systems and devices that generate a substantial amount of pollution are transformed (if possible) into electrical devices (i.e., electrified), and all the electrical energy that powers those devices is generated from renewable energy sources, the result would be a significant decrease of CO2 contributors. With transportation making up 60% of the world’s carbon emission, this chapter is concentrated on the electrification process of vehicles by usage of electrical devices thus transforming them into electrical vehicles. Although the electric vehicle has become the representative of the renewable energy revolution, it has its own flaw’s. The electric vehicle’s powertrain consists of electric motors, AC/DC inverters, DC/DC converters, braking choppers, transmission, but there is one system that is considered the core of the electric vehicle, the battery package. The electric vehicle’s battery package (i.e., Battery Pack) is the main source of power for all the onboard systems. It contains the energy to power the electrical propulsion system, main systems (inverter, VCU - Vehicle Control Unit, servo system, cooling system, lights, etc.), media system (Infotainment), secondary systems (HVAC – Heating, ventilation and air conditioning, cabin lights, charger, etc.). This underscores the battery package’s importance and defines the need for it to be as efficient, reliable, safe, and environment friendly as possible. The battery cell with the efficiency of 99% is the building block of the battery pack and not only that it comes in different shapes and sizes (cylindrical, pouch, prismatic), but also in different chemical compositions (LiMn2O4, LiNiMnCoO2, etc.). The lithium-ion battery cell is the most commonly used battery cell, because when compared to other battery technologies it has the most energy density per kg. The conventional way of building a battery pack is done with a serial-parallel combination of battery cells. The number of battery cells in a battery pack depends on the battery cell specifications and the required energy of the battery pack. The number of battery cells in a serial string depends on the required battery pack voltage, and the number of battery cells connected in parallel depends on the required battery pack capacity. With all the above in mind, the lithium- ion battery cell needs to operate within certain conditions (temperature range, current discharge rate, voltage/current charging). If these conditions are not met, the battery cell’s health will degrade, and this can lead to thermal runaway. This results in damage not only the battery pack, but the entire vehicle. It is needless to say that the safety of the vehicle’s operator would be in jeopardy. The imbalance of battery cells in a serial string contributes to faster battery pack degradation, and results in a substantial amount of defective battery cells inside the battery pack. With that in and its enclosed property in mind, this leads to a high number of discarded battery packs. This results in a constant increase of discarded non- recyclable battery cells. To prevent all of this, innovations in the battery management system (i.e., BMS) are required. The BMS combined with the appropriate sensors is used for monitoring, control and diagnosis of the battery pack. The main goal of the BMS is the battery pack’s safe, uninterrupted and highly optimized electrical energy supply. The BMS contains various safety functions (interlocks, thermal runaway prevention functions, and overcurrent functions), monitoring functions (state of health estimation, current, voltage and temperature analysis) and optimization functions (battery cell balancing). This is achieved with the master-slave architecture, where the battery pack is divided in segments (modules), where the slave module controls and monitors each segment via the master module. The battery pack’s segment usually contains a number of serial- parallel connected battery cells. This may be the conventional architecture but not the economic or safest architecture. A new architecture concept achieves all the desired goals. This architecture concentrates on breaking the battery pack into even smaller segments (modules), which allow monitoring on a smaller scale. This results in higher efficiency and greater balance of the battery cells, which leads to a decrease in the battery cell degradation rate. This combined with a modular architecture of the battery pack, where the modules are exchangeable, result in a decrease of discarded battery cells. The battery cell degradation rate is decreased even further by introducing super capacitors into the architecture. With the property of high current charge/discharge rate, the super capacitor’s role is to take in any high current surge that the battery cell may experience, during regenerative braking or ramping up of the electric motor. Along with regenerative braking, auxiliary sources of energy (alternators, generators, range extenders, solar panels, etc.) are used to charge the battery pack while in operation, which results in wider usability range and a reduction in charging frequency of the electric vehicle and also extends its drive range.

Izvorni jezik
Engleski

Znanstvena područja
Elektrotehnika

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