Design And Construction A Lithium Battery Charger

1.0 INTRUDUCTION
1.1 BACKGROUND OF THE PROJECT
A lithium-ion battery or Li-ion battery is a type of rechargeable battery in which lithium ions move from the negative electrode through an electrolyte to the positive electrode during discharge, and back when charging. Li-ion batteries use an intercalated lithium compound as the material at the positive electrode and typically graphite at the negative electrode.
Li-ion batteries have a high energy density, no memory effect and low self-discharge. Cells can be manufactured to either prioritize energy or power density (Lain et al. 2019). They can however be a safety hazard since they contain flammable electrolytes, and if damaged or incorrectly charged can lead to explosions and fires. Samsung was forced to recall Galaxy Note 7 handsets following lithium-ion fires (Kwon et al, 2016) and there have been several incidents involving batteries on Boeing 787s.
A prototype Li-ion battery was developed by Akira Yoshino in 1985, based on earlier research by John Goodenough, M. Stanley Whittingham, Rachid Yazami and Koichi Mizushima during the 1970s–1980s, and then a commercial Li-ion battery was developed by a Sony and Asahi Kasei team led by Yoshio Nishi in 1991.[Ballon et al, 2008]
Lithium-ion batteries are commonly used for portable electronics and electric vehicles and are growing in popularity for military and aerospace applications [Ballon et al, 2008].
This work is aimed at building an automatic charger for “lithium-ion battery”.

1.2 PROBLEM STATEMENT
In the last decade battery charger built then only charge and keep charging the battery even when the battery is fully charged, and this exposes the battery to overcharge and explosion, this can also cause a lot of headaches and prevent us from getting the life expectancy out of the batteries we purchase. To solve this problem, an auto-turn of charger was built. A battery will never get overcharged with an Auto turn off battery charger.

1.3 AIM AND OBJECTIVES OF THE PROJECT
Depending on the design and chemical compounds used, lithium cells can produce voltages from 1.5 V to about 3.7 V. the main aim of this work is to build an automatic charger for lithium batteries. The objectives are:
i. To build a low cost lithium battery charger.
ii. To protect the charger from overcharge
iii. To have a good charging system for mobile devices.

1.4 SIGNIFICANCE OF THE PROJECT
Working on this topic will expose us to all the benefit of building charger for mobile devices that contain lithium batteries. This charger provides the full life expectancy out of the batteries we purchase.
ii. Easy to use.
iii. Simple circuit.
iv. components are easily available and low cost.
v. User friendly product.

1.5 APPLICATIONS OF THE PROJECT
This battery charger with little modifications can charge any battery ranging from 0 to 15V. Some of the applications are:
i. Rechargeable Cells
ii. Motorcycle Batteries
iii. Mobile phone charger and other mobile devices

1.6 LIMITATION OF THE PROJECT
The charger has adjustable voltage function that makes it compactable with different lithium batteries.

1.7 SCOPE OF THE PROJECT
The scope of the project covers building a charger that charges lithium cells and also automatically shut off the charging process when battery attains full charge. This prevents the deep charge of the battery. If the battery voltage is below the set value, then circuit automatically charges the battery.

1.8 METHODOLOGY
To achieve the aim and objectives of this work, the following are the steps involved:
i. Study of the previous work on the project so as to improve it efficiency.
ii. Draw a block diagram.
iii. Test for continuity of components and devices,
iv. Design and calculation for the device was carried out.
v. Studying of various component used in circuit.
vi. Construction of the circuit was carried out.
vii. Finally, the whole device was cased and final test was carried out.

1.9 PROJECT ORGANISATION
The work is organized as follows: chapter one discuses the introductory part of the work, chapter two presents the literature review of the study, chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.