Sel litium ion telah digunakan dalam kebanyakan barangan di sekeliling kita seperti telefon bimbit, kamera digital komputer riba, dan lain-lain peranti elektronik dan kebelakangan ini terdapat banyak permintaan aplikasi dengan penggunaan bateri yang tinggi seperti kenderaan hybrid dan elektrik. Selari dengan penggunaan aplikasi yang semakin meluas, saiz bateri diperlukan juga semakin meningkat berserta kualiti yang tinggi. Sistem pengurusan bateri perlu menambahbaik prestasi bateri yang semakin bertambah permintaan supaya berupaya untuk menggunakan bateri secara keseluruhan. Sistem pengurusan bateri terjejas oleh tiga jenis ketidakseimbangan sel iaitu ketidakseimbangan keadaan sel, perbezaaan jumlah kapasiti dan perbezaan galangan yang mana kemudian akan mengakibatkan degradasi sel pramatang, bahaya keselamatan, penamatan caj awal kerana mengenakan caj berlebihan dan juga penamatan awal lebihan caj dilepaskan. Bagi mengelakkan ketidaksempurnaan penggunaan tenaga, bahaya keselamatan, dan kekurangan pemanjangan hayat bateri, satu cadangan mengenai imbangan sel berdasarkan jangkaan keadaan caj telah diajukan. Parameter yang terlibat dalam keadaan caj dikaji dan telah dijalankan untuk membuktikan dan membandingkan ketepatan jangkaan keadaan caj. Dalam projek ini, bateri litium ion boleh dicas semula digunakan dan data daripada pengilang digunakan sebagai rujukan untuk mendapatkan peratusan ketepatan data yang dicatat dalam eksperimen. Kajian mengenai jangkaan keadaan caj akan menumpukan pada parameter-parameter yang ketara iaitu suhu, jam ampere, voltan dan kapasiti. Kesemua parameter terlibat dalam pembelajaran sistem imbangan sistem penyimpanan tenaga bateri selari dengan garis panduan yang betul dan cadangan daripada pengilang bateri yang digunakan.
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Lithium ion (Li-ion) cells have been used in almost everything around us such as cell phones, digital cameras, laptop computers, and in many other electronic devices and nowadays there are more demanding applications with higher usage battery like Hybrid and Electric Vehicles (HEV). With bigger applications, we need bigger size of batteries as well as higher quality in their performance. Battery management system needs to improve the performance of the battery with such high demands to be able to deliver the full use of the battery. Battery management systems are affected by three types of battery cell imbalance which are state of charge (SoC) imbalance, total capacity differences and impedance differences which later results in premature cell degradation, safety hazards, early charge termination due to overcharged and also early discharge termination. To avoid on incomplete use of energy, safety hazards, and reduced longevity of battery life, an approach on cell balancing based on state of charge estimation is proposed. The parameters that affected the state of charge (SoC) are investigated and the study is carried out to prove and compare the accuracy of the state of charge (SoC) estimation. In this project, Li-ion Rechargeable Battery is used and the battery’s manufacturer data is used as reference to obtain the percentage on accuracy of the results from the experiment. The study of state of charge (SoC) estimation is focusing on the most obvious parameters which are temperature, ampere-hour, voltage and capacity. These parameters involved in the study of balancing system of battery energy storage system along with proper guidelines and suggestions by the manufacturer of the battery used.
State-of-charge estimation for balancing control in a battery energy storage system / Nur Hidayah Hashim